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IntroductionThe modern automobile industry is developing very rapidly. Take car keys for example, the traditional mechanical keys are basically replaced now. Because our remote control keys and even smart keys are already very common. However, this also brings some troubles to many consumers-what should I do if the key is out of power or the battery is damaged? How to replace the battery? What type of battery should I choose?For example, in most cases, temperatures too high or too low still compromise their ability to store and release energy. Put simply, cold weather will decrease the lifespan of your battery because it will require charging more often. Here will give you some basic ideas of car key batteries comparison in modern life.CatalogIntroductionⅠ What Are CR Batteries?1.1 CR×××× Definition1.2 CR Button Battery ExamplesⅡ SummeryⅠ What Are CR Batteries?1.1 CR×××× DefinitionGenerally speaking, the batteries of car keys are button batteries, which have a relatively long service life. Conventionally, a battery can be used for more than 3 years. To replace the battery of the car key, you must buy the right model. Not all car keys use CR2032, while CR2450, CR2025, and CR2016 are also optional. Here, what models are CR2032 and CR2025? What does CR stand for in battery? According to IEC rules, in Lithium batteries, Chromium is also used in it that is why it's also called CR batteries. Most of the people related CR with the button or coin batteries but it's a chemical designation of Chromium.C-denotes Lithium Manganese Dioxide.R-after another letter denotes a round cell with the chemistry shown by the first letter.Digit-The next four digits indicate the size, the first two digits indicate the diameter, and the last two digits indicate the thickness.All the batteries who have this chemical substance in their batteries they can use this abbreviation CR.1.2 CR Button Battery Examples🚩CR2032 BatteryMax Size: 20.0×3.2mmNominal Capacity: 240mAhNominal Voltage: 3.0VOperating Temperature: -20°C ~+60°CRef.Weight: 3.0gCR2032 batteries is the most common battery coin providing long-lasting, reliable power for various devices. They are used to power small electronics devices such as calculators, wrist watches, various medical devices, fitness appliances, toys etc. As for CR2032 run time, that is, how long should a 2032 battery last? For example, a typical LED uses about 20mA and the capacity of a CR2032 Coin Cell is 200mAh. 🚩CR2016 BatteryMax Size: 20.0×1.6mmNominal Capacity: 90mAhNominal Voltage: 3.0VStandard Current: 0.1mAMax Continuous Current: 1.0mAMax Pulse Current: 15mARef.Weight: 1.8gCR2016 batteries are commonly used in calculators, digital watches, memory back-up, laser pens, car key remotes, calculator, toys, fitness appliances and medical devices like a clinical thermometer and a tensiometer. It has a proven track record for appliances where conventional batteries cannot be used. 🚩CR2025 BatteryMax Size: 20.0×2.5mmNominal Capacity: 170mAhNominal Voltage: 3.0VMax Continuous Current: 2.0mAMax Pulse Current: 20mARef.Weight: 2.5gCR2025 batteries provide long-lasting reliable power in various devices. This battery is frequently used in car key remotes, medical devices, digital watches, fitness devices and other electronics. 🚩CR1632 BatteryMax Size: 16.0×3.2mmNominal Capacity: 120mAhNominal Voltage: 3.0VMax Continuous Current: 1.0mAMax Pulse Current: 15mARef.Weight: 1.8gCR1632 batteries mainly used for low power consumption electronic products, generally its output current from 0.001mA to 5mA. For example, CR1632 batteries are often used in car key remotes, watches, toys and other electronic appliances. Also it provides long-lasting reliable power. Store in room temperature, ventilated, dry environment (humidity not more than 60%), having period of validity up to 2 years. 🚩CR2450 BatteryMax Size: 24.0×5.0mmNominal Capacity: 520mAhNominal Voltage: 3.0VOperating Temperature: -30°C ~+60°CMax Continuous Current: 3.0mAMax Pulse Current: 20mARef.Weight: 5.8gVery high weight-to-power ratioNo mercury addedHigh leak protectionCR2450 batteries have certain accomplishments for applications where traditions where traditional cannot be used. Use them for calculators, digital watches, laser pens, car keys, medical devices like a clinical thermometer and a tensionmeter and fitness appliances. Store in room temperature, ventilated, dry environment (humidity not more than 60%), having period of validity up to 3-5 years.🚩Recommended Readingcr2025 vs cr2032cr2016 vs cr2032Ⅱ SummeryThey are not rechargeable, and are all lithium primary batteries. That is, they are very similar to each other. The shelf life of lithium coin cells stored at normal room temperature and relative humidity is 10 years. If the manufacturing level is not high or the quality control is not good, their life will be greatly shortened. What’s more, if the use environment is ideal, their life span can reach 10 years or more. They are often used on computer motherboard CMOS batteries, memory functions or power-off protection modules, electronic scales, calculators, electronic dictionaries and other products, and can also be used on car remote control keys. With the requirements of new industries, there are also specially improved with very different capacities, mainly to improve their high-current output capabilities, such as those used in flashing lights or RF products.From the above, we can see the difference between them. As for interchangeable batteries, if you are a consumer, replace the battery with the same one that was originally intended, as the holder was designed to fit either one or the other.A derivative problem, what happens to old lithium batteries? Since they cannot be recharged, they has to be disposed of properly. For proper disposal of large numbers of lithium batteries at the same time, they can be disposed of by scattering them in different directions so that they will not touch one another. In short, you can't throw away lithium-ion batteries with your regular trash or even in your blue recycling bin. What you should do is dropping them off at a battery recycling center or battery drop-off, or requesting a battery pick-up through your local government's website. Frequently Asked Questions about Difference between Cr2032 and CR2025, CR2016, CR24501. Can I replace a CR2016 battery with a CR2032?They are not the same in thickness, the cr2016 is thinner then the cr2032 although if you stack two of the cr2016 batteries then it will then be the same thickness as the cr2032 battery and they both worked for the car stereo remote and key fob. That is, if it fits in the device's battery slot and makes a good electrical connection, a CR2016 can substitute for a CR2032. However, it will have less than half the CR2032's lifetime. 2. Can I use a CR2032 in place of a CR2025?2032 and 2025 are literally the dimensions of the battery. For as long as either fits in the battery compartment, the CR2025 and CR2032 may be used interchangeably with minimal effect although the CR2032 would probably last slightly longer simply because it has a higher capacity (mAh). 3. Are CR1632 and CR2032 interchangeable?The CR1632 battery is very similar to CR2032 or CR2025 but they are not interchangeable because of their dimensions. The name CR1632 indicates that the battery is 16mm wide and 3.2mm thick. It is rated for 3V and 130mAh capacity. 4. Is CR2450 the same as CR2032?CR2450 vs CR2032CR2450 is often compared with a very popular lithium 3.0 volts CR2032 battery. Output voltages of these batteries are the same for the same chemistry types. However, due to the larger volume of CR2450, it features a larger capacity - 600-620 mAh (CR2450) vs 210-230 mAh (CR2032). 5. What battery is equivalent to CR2032?

Ⅰ IntroductionThe energy storage units of several devices we come across every day are batteries; they are available in various shapes, sizes, parameters, and shapes. They can usually be found in vehicles, emergency power sources, mobile devices, tablets, iPads, and many other portable electronic devices. But not all devices will use the same type of battery; each device has its own specifications and power supply requirements, and to choose the right battery for your application, you will need a battery selection guide. So, the considerations to consider when choosing a battery for your next electronic product design will be investigated in this post. If you are completely new to batteries, then it is recommended that you read this article on battery types and their applications before continuing further to understand the fundamentals of batteries selection.CatalogⅠ IntroductionⅡ Some Factors to ConsiderⅢ Rechargeable / Non-Rechargeable BatteriesⅣ Availability of SpaceⅤ System Operating VoltageⅥ Operating TemperatureⅦ Capacity-Power & EnergyⅧ ChemistryⅨ CostⅩ Shelf LifeⅪ How to Choose a BatteryⅫ FAQⅡ Some Factors to ConsiderYou must be aware of the important parameters involved in its activity when selecting a battery for your application. The truth of the battery is that, because no battery is ideal, there is no common form of battery for all applications. You should be able to manage the exhaustion of other parameters when you choose to use one parameter of the battery.  For example, if you want your battery to provide a lot of energy for your application, the internal resistance of the cell should be reduced, which can only be accomplished by increasing the surface area of the electrode. Inactive components such as current collectors and conductive aid are also improved by this because energy density is traded off to gain power. You must give up anything to get the other in a battery in order to get exactly what you want in your application. In the following picture, the important battery parameters are given.Now, to understand its significance and effect on battery efficiency during service, let's briefly look at each battery parameter.Ⅲ Rechargeable / Non-Rechargeable BatteriesIn deciding between a main and secondary battery, there might not be much uncertainty, you only have to decide whether you want the battery to be used once or several times. The primary (non-rechargeable) battery can be used for occasional applications such as toys, flashlights, smoke detectors, etc. They are also used in products such as pacemakers, wristwatches and hearing aids where charging is not feasible. The secondary (rechargeable) batteries can be used in applications where a standard power source such as cell phones, computers, cars, etc. is needed. Compared to primary batteries, secondary batteries often have a higher self-discharge rate because of their ability to recharge, which is an ignorant fact.Ⅳ Availability of SpaceThe batteries, including button cells, cylindrical cells, pouch cells and prismatic cells, are available in different shapes and sizes. In order to make your computer comfortably portable, the battery size really matters. AA, AAA and 9V batteries suitable for portable devices are the standard sizes available. In applications where there is less room but more power needed, lithium batteries (pouch type) are widely preferred. If the power demand is lower since they are very lightweight and the smallest of battery types, coin cells may also be considered.Ⅴ System Operating VoltageOne of the most significant characteristics of the battery, which is calculated based on the electrode & electrolyte used, is the battery voltage (Chemical Reaction). There is a common misconception that in any device, it is not the case that a fully discharged battery would have 0V. In fact, if the battery reads 0V, it's probably dead. A battery's output voltage should always be read from its nominal voltage level. Water is used as an electrolyte by the zinc-carbon battery and nickel-metal hydride battery and provides a nominal voltage of 1.2V to 2V, while the lithium-based batteries use organic electrolytes that can provide a nominal voltage of 3.2 to 4V. Most of the equipment's electronic parts run in the 3V voltage range. A single cell battery would be enough to power the equipment if you use a lithium-based battery. Note that the battery voltage will not be constant and will differ between the minimum value and the maximum value, depending on the battery power available. This is the minimum and maximum value shown below for each battery. Your nominal voltage would only be 3.2V to 4V if your circuit is running at 5V and you are charging it with a lithium battery. Boost converter circuits are used in these cases to convert the battery voltage required for the circuit to 5V. If your operating voltage is very high, like 24V or 12V, you can either use a 12V lead-acid battery or combine more than one lithium cell in series to increase the resulting output voltage if you need high power density.Ⅵ Operating TemperatureFor example, the battery operating with aqueous electrolytes can not be used in temperature conditions below 0 ° C as the aqueous electrolyte could be frozen below 0 ° C, in the same way,  the lithium-based batteries could work up to -40 ° C, but the efficiency could be reduced. The battery performance can be drastically modified by the temperature. The optimum charging rate for the lithium-ion batteries is between the temperature ranges of 20 ° C to 45 ° C. If you want to use a lower current/voltage outside this temperature range, this will result in a longer charge time. Lithium dendrite plating can be produced in the electrolyte if the temperature drops below 5 ° C or 10 ° C, which must be avoided by trickle charging.Ⅶ Capacity-Power & EnergyThe battery's strength determines the battery's runtime. Battery power/capacity is expressed in watt-hours (Wh). By multiplying the battery voltage (V) by the amount of current a battery can produce over a given amount of time, the watt-hour is determined. The battery voltage is almost set and the current that can be supplied by a battery is written on the battery, expressed in the Ampere-hour rating (Ah or mAh). Consider a 5V battery with a capacity of 2 amp-hours (Ah), so it has a power of 10Wh. The 2Ah battery will produce 2 Amps for 1 hour or 0.2A for 10 hours or 0.02A (20mA) for 100 hours. At a given discharge rate, temperature, and cut-off voltage, battery manufacturers often specify the power, where the capacity always depends on all three variables. A battery's capacity can tell us how much energy it can supply to an application. For instance, consider a 12V, 10Ah car battery, the battery's actual capacity is 120Wh (12V x 10Ah), but it will have a capacity of 36Wh in a 3.6V laptop battery that has the same 10Ah dissipation (3.6Vx 10Ah). You can see from the example that the amount of power a car battery can hold is three times higher than a laptop battery, even though they have the same Ah.High-power batteries always have quick discharge capabilities at high drain speeds, such as power tools or applications for vehicle starter batteries, with poor energy capacity for most high-power batteries.Ⅷ ChemistryYou would have learned by this time that all the characteristics of a battery are often dependent on the chemistry involved in the battery, so when selecting the type of battery, you should be more conscious. Batteries are known as Lead Acid Batteries, Alkaline Batteries, Ni-Cad Batteries (Nickel Cadmium), Ni- MH Batteries (Nickel Metal Hydride), Li-Ion (Lithium-Ion) and LiPoly (Lithium Polymer) Batteries based on the chemistry used in the process.Ⅸ CostThe battery will be one of the costly things in the Bill of Materials (BOM) for most portable electronic devices, so it will impact the total cost of your electronic applications most of the time. Therefore, you should know your product specifications and budget and then pick the right battery for your product.Ⅹ Shelf LifeNot all batteries are used directly after development, but they remain on the shelf for a long time before they are used. A battery's shelf life informs you how long it is possible to keep a battery unused. In primary batteries, the shelf life is largely known as a reality only because the secondary batteries can be recharged once they are used. The battery could sit idle there for years, for example, in a fire alarm siren device, until it detects a fire and activates the alarm. The battery maintains its output even if it is left unused for a long time, so care should be taken.Ⅺ How to Choose a BatteryNow that we've looked at the criteria that you should consider before selecting the battery for a portable electronic application, let's look at the common battery selection cases. Bear in mind that these are just tips and not difficult written guidelines.• You can use lead-acid batteries for items that consume more electricity, including projectors, large sound systems, and motorized projects. You can go for 'Sea deep cycle' batteries if you're going to have heavy battery use.• You can go for the lithium coin cells or small lithium polymer cells if your electronics need to be very small, about an inch on either side.• If you are going to manufacture the part, use inexpensive alkaline batteries of common sizes in large quantities. So the client considers it easy to replace them.• If you want the product to be user-serviceable, the battery can be adjusted by the customers themselves for batteries of 9V or AA capacity.• Use 3 Alkaline (4.5V) or 4NiMH (4.8V) cells if the circuit needs an input of approximately 5V.• Use a battery holder from your local shop to build a rechargeable battery pack and stick it with NiMH batteries and then begin recharging your battery.• If you want to replace any of the rechargeable batteries with your alkaline battery, test your system to make sure it will work at a lower voltage without any problems.• Always use a high-quality charger with sensors to ensure proper charging and trickle charging if you want your battery to have a longer life span since using a cheap charger would destroy your cells in the battery pack.How To Buy the Right Battery for Your CarⅫ FAQ1. How do I choose a battery?Factors to be considered while choosing a BatteryRechargeable / Non-Rechargeable batteriesAvailability of SpaceSystem Operating VoltageOperating TemperatureCapacity of the battery - Power & EnergyBattery ChemistryCost of Battery 2. What size battery does my car take?Your car's battery group size can be found in the battery section of the owner's manual. If you no longer have access to your original owner's manual, you may also consult the reference guides provided by battery retailers to determine the appropriate battery group size for your car. 3. How many Ah battery do I need for home?The battery you need will have to be powerful enough to provide the required power for at least 2 hours. As battery voltage is generally taken at 12 Volts, here is how you calculate the battery capacity. So, a battery with capacity equal to or higher than 140 Ah will suffice for your home. 4. How do I choose the right battery?To get the right battery power for your vehicle, you need to consider the cold cranking amps (CCA) and reserve capacity (RC). Cranking amps is the measure of your battery's starting power and should always match the standard requirements of your vehicle. Check the owner's manual for these specifications. 5. What brand of car battery lasts the longest?Best Rated Car Batteries for Long Lasting Performance 2020Optima RedTopExide Edge AGM Sealed BatteryOdyssey PC680ACDelco 94RAGM Professional

I OverviewValve regulated lead acid battery (VRLA battery) is generally divided into gel battery and AGM battery. Figure 1. Classification of VRLA BatteryGel battery is a valve regulated lead acid battery made by gel technology which not only refers to whether the battery contains gel electrolyte, but also includes the battery design ideas, structural characteristics, manufacturing technology and other technical measures to ensure the corresponding performance of the battery.Figure 2. Gel BatterySimilarly, for AGM battery, it also refers to valve regulated lead acid batteries manufactured by AGM technology. To hold the sulfuric acid in the battery with AGM separator is only one of the technical features of AGM battery.Figure 3. AGM BatteryBecause the two technologies are completely different, there is a great difference in performance between gel battery and AGM battery. In order to better understand the performance difference between gel battery and AGM battery, this article deeply discusses their differences in terms of battery design.Sealed Lead Acid Battery Recovery(The man in the vedio shows how to clean, open, refill, desulfate and test a totally dead sealed lead acid battery.)CatalogI OverviewII AGM vs. Gel Batteries: Electrolyte Fixation TechnologyIII AGM vs. Gel Batteries: ElectrolyteIV AGM vs. Gel Batteries: Polar Group4.1 AGM Battery has Excellent LargeCurrent Discharge Performance4.2 Make Full Use of Active Substances4.3 Conducive to the Transmission of Oxygen4.4 Prevent the Battery from Entering the Life Decline Period RrematurelyV AGM vs. Gel Batteries: Oxygen CycleVI AGM vs. Gel Batteries: CostVII ConclusionVIII AGM vs.Gel Batteries QuizII AGM vs. Gel Batteries: Electrolyte Fixation TechnologyBecause both gel battery and AGM battery adopt cathodic absorption maintenance-free technology based on internal oxygen cycle, there is no essential difference in maintenance-free technology, only in the way of fixing electrolyte.For the AGM battery, the AGM manufacturing technology is adopted, and the electrolyte in the battery, which is dilute sulfuric acid, can be held in the glass separator. The electrolyte is fixed by making use of the porosity of the glass separator, which has a strong adsorption, allowing the electrolyte to become immobilized. Its principle is similar to the principle of water absorbing sponge.Figure 4. Water Absorbing SpongeBecause dilute sulfuric acid is made of pure sulfuric acid and water, the density of pure sulfuric acid is 1.84g/cm3, and the density of pure water is 1.0g/cm3. In the backup battery, the storage battery is kept stationary for a long time. Due to the effect of gravity, the dilute sulfuric acid electrolyte will stratify, that is, the sulfuric acid density at the bottom is high, while the sulfuric acid density at the top is low. In high-type batteries, this delamination phenomenon is particularly evident. Therefore, in conventional batteries, the height of the battery generally does not exceed 400 mm.Figure 5. Delamination of ElectrolyteThe layering of the electrolyte will make the active material on the top of the electrode plate unable to release the capacity it should have because of insufficient acid, and it will be overcharged during charging. And the bottom will be difficult to charge because the sulfuric acid concentration is too high. At the same time, due to the delamination of the acid, concentration polarization back-EMF will also be generated in the upper and lower parts of the electrode plate, which ultimately reduces the operating voltage and capacity of the battery. Furthermore, excessively high sulfuric acid at the bottom will also accelerate the corrosion of the bottom grid and the sulfation of the plates, thereby shortening the battery life.For gel battery, it adopts gel manufacturing technology, and the electrolyte in the battery is fixed in the silicon gel. The fixation of the electrolyte is due to the silicone space network structure formed by the polymerization of gel gel particles to effectively fix the sulfuric acid electrolyte. The principle is similar to the use of jelly to fix the sulfuric acid electrolyte. In the space network, the silica gel is the skeleton supporting the entire network, and the sulfate ion can move freely at a certain level, which can ensure the smooth progress of the battery chemical reaction, that is, the smooth charge and discharge of the battery.Figure 6. Gel Battery ElectrolyteBecause the spatial network structure of silica gel is rich in a large number of silicon oxidation bonds, it can form hydrogen bonds with hydrogen in the sulfuric acid molecule. Due to this weak chemical action, the silica gel easily adsorbs and releases sulfuric acid molecules. Even if the electrolyte is not moved for a long time, due to the existence of this effect, it can basically offset the effect of gravity, so that the diluted sulfuric acid electrolyte is evenly distributed up and down, and it is not easy to cause delamination. Furthermore, the average pore size of the gel itself is about 100 times smaller than the average pore size of the AGM separator, and the comparative area of the gel itself is much larger than the specific surface area of the AGM separator. The small pores or micropores can be better keep sulfuric acid electrolyte. In the gel battery, since the electrolyte is not layered, the active materials on the upper and lower parts of the inner electrode plate of the battery can be fully utilized, so the battery has a long life span and can also be manufactured as a high-type battery.Figure 7. NO Delamination of ElectrolyteIII AGM vs. Gel Batteries: ElectrolyteThe AGM battery uses an AGM separator to fix the sulfuric acid electrolyte. In order to make the oxygen generated in the positive electrode in the later stage of charging easy to pass through the separator to the negative electrode and be absorbed by the negative electrode, a lean liquid design must be adopted to ensure the smooth progress of the internal oxygen cycle. The so-called lean electrolyte design takes the sponge's liquid absorption as an example. Under normal conditions, a sponge can be 100g of water. The actual design is only to allow the sponge to absorb 80~90g of water. This design is a lean electrolyte design. Therefore, the amount of sulfuric acid electrolyte in the AGM battery is relatively small. In lead-acid batteries, the sulfuric acid electrolyte is involved in the electrochemical reaction of the battery. In order to ensure the discharge performance of the battery (the amount of sulfuric acid needs to be sufficient), it can only be achieved by increasing the sulfuric acid concentration. Therefore, AGM batteries generally use higher density/concentration sulfuric acid.Due to the small amount of electrolyte in the AGM battery, the high concentration of sulfuric acid has a series of adverse effects on the battery itself. Since the amount of electrolyte in the AGM battery is relatively small and the heat capacity of the battery is also small, the AGM battery is sensitive to temperature. For batteries with the same capacity that can be fully charged, if the same amount of electricity is charged, the temperature rise of the AGM battery is significantly greater than that of the gel battery.For AGM batteries, due to the use of higher concentration of sulfuric acid, the grid corrosion is faster, and it is easier to produce inert lead sulfate, which makes the battery's charge acceptance worse, and the battery is more difficult to charge. That is, AGM batteries are more prone to early capacity decay. With the extension of battery life, the AGM battery continuously loses water due to overcharging, and the sulfuric acid concentration in the battery rises slowly, which is more serious. In batteries, the sulfuric acid saturation of the AGM separator is usually 95% to 85%. Compared with a fully saturated separator, when the saturation is 85%, the effective internal resistance of the battery increases by 90%. When the sulfuric acid saturation of the separator in the battery is less than 85%, the battery life will quickly end due to excessive tail current, lack of acid and excessive internal resistance. Therefore, for AGM batteries, the battery loses 10% of its water, and the life of the battery is reduced by more than 50%.Figure 8. Influence of AGM Battery Lean Liquid Design on Battery PerformanceThe development of the gel battery itself is based on the improvement of the flooded battery. Because the sulfuric acid electrolyte is fixed by silicon gel, the gas transmission inside the gel battery is completed through the channel formed by the cracks generated by the gel cracking. The amount of electrolyte does not affect the gas transmission channel. Therefore, there is no strict limit on the amount of electrolyte, and the liquid-rich design is usually adopted to ensure that the battery has better performance. Therefore, the amount of electrolyte in the gel battery is relatively large. For large-density batteries, the amount of rich liquid is about 20%, and for medium-density batteries, the amount of rich liquid is about 15%. Gel batteries generally use a lower concentration of acid than AGM batteries. At a lower acid density, the corrosion rate of the grid is lower, and the battery's charge acceptance is also significantly improved, thereby extending the battery's life span. Secondly, the gel battery has more electrolyte. The more electrolyte, the greater the heat capacity of the battery, so the gel battery is not very sensitive to temperature. The high temperature has relatively little effect on the performance and life span of the gel battery. In addition, due to the high voltage or maintenance operations such as equalizing or overcharging the battery during long-term use, the battery may lose water. The gel battery has more electrolyte and a small amount of water loss, which has little effect on the life of the battery. Therefore, the life span is longer and the battery stability is better.How a lead-acid battery works(The man in this vedio explains the essential principles of a lead-acid battery. )IV AGM vs. Gel Batteries: Polar Group In AGM batteries, the assembly compression ratio of the pole group has a very important impact on the battery performance and battery life.Appropriately increasing the pole group assembly pressure of the battery has the following benefits:4.1 AGM Battery has Excellent LargeCurrent Discharge PerformanceThe AGM battery adopts a tight assembly structure, so that the distance between the positive and negative plates is smaller, and the distance of ion conduction in the battery is shorter. Thereby reducing the internal resistance of the battery. Furthermore, with the tight assembly structure, the electrode plate and the separator maintain good contact, and the contact resistance between the separator and the electrode plate is also reduced. These make AGM batteries more conducive to large current discharge.4.2 Make Full Use of Active SubstancesBecause the AGM separator not only plays the role of isolating the positive and negative plates, but also plays the role of storing and maintaining the electrolyte. Adopting a tight assembly structure, the polar plate is close to the AGM separator, which allows the electrolyte to impregnate the entire polar plate, so that the active material is fully utilized, and the use capacity of the battery is increased.4.3 Conducive to the Transmission of OxygenWith a tight assembly structure, the polar plate is in close contact with the AGM separator, which is conducive to the smooth diffusion of oxygen through the separator to the negative electrode. Because the polar plate is under a large pressure, the AGM separator is compressed, and the micropores in the AGM separator perpendicular to the direction of the separator become larger, making oxygen easily penetrate the separator from the positive electrode to the negative electrode.On the other hand, because the AGM separator is compressed, the pores parallel to the direction of the separator plate become smaller, thereby suppressing the escape of oxygen generated in the positive electrode along the plane direction of the separator.4.4 Prevent the Battery from Entering the Life Decline Period RrematurelyTo prevent the battery from entering the life decline period prematurely, AGM separator has a strong liquid absorption performance and a high porosity. It is a separator made of hydrophilic glass fibers and does not contain a binder. The separator itself has poor strength. The material of the AGM separator is shown in Figure 9 below.Figure 9. Glass Fibers Put the AGM separator in boiling water for 1 hour, the AGM separator may disintegrate into pure glass fiber. If the AGM battery is loosely assembled, the escape of oxygen generated at the end of the battery charge may change the microstructure of the AGM separator, making the battery prone to early capacity decay. The tight assembly structure can effectively suppress the softening and shedding of the positive electrode active material, thereby greatly extending the life span of the AGM battery. Therefore, the AGM battery must adopt a tight assembly design. This structure not only makes the oxygen circulation in the battery more smoothly, but also ensures that the AGM battery has excellent large current discharge performance and better life span.In a gel battery, the viscosity of the gel electrolyte is much greater than that of dilute sulfuric acid, so if the assembly is too tight, it is not conducive to the gel electrolyte entering the pole group. Therefore, the assembly of the pole group is relatively loose. The separator used is usually a microporous plastic separator containing ribs to facilitate the gel electrolyte to enter the pole group and the inside of the separator. The separator of the gel battery mainly serves to isolate the positive and negative plates. The gel battery itself is developed on the basis of the rich liquid battery, and basically maintains the characteristics of the original rich liquid battery, and there is no strict requirement for the assembly pressure of the battery pole group. In the gel battery, due to the loose requirements for the assembly of the pole group, the distance between the positive and negative plates is relatively large, and the ion conduction distance in the battery is long, so the internal resistance of the gel battery is usually large, which is more suitable for medium current and small. When the current is discharged, the large current performance of the battery is relatively poor. V AGM vs. Gel Batteries: Oxygen Cycle In VRLA batteries, oxygen is transferred from the positive electrode to the negative electrode, where it is compounded. According to the principle of oxygen circulation, the recombination of oxygen at the negative electrode mainly occurs at this three-phase interface.There are two ways of oxygen transmission: one is vertical transmission, that is, the oxygen generated by the positive electrode first moves to the periphery of the pole group, and then reaches the negative electrode plate. The second is horizontal transmission, that is, the oxygen generated by the positive plate directly penetrates the separator to reach the negative electrode.In VRLA batteries, the gas channel that generates oxygen circulation not only occurs in the separator between the positive and negative plates, but also occurs in the outer space of the pole group. In AGM sealed batteries, the gas generated from the positive electrode needs to grow from small bubbles to larger bubbles at the end of charging or during the float charging process. As the bubbles continue to grow, they expand into the AGM separator, and the sulfuric acid electrolyte in the large pores in the separator is discharged to form a gas channel, and oxygen is transferred from the positive electrode to the negative electrode.Figure 10. VRLA BatteryTherefore, only when the oxygen pressure generated by the positive electrode reaches a certain level, a number of oxygen channels will be formed in the AGM separator. After the gas is transferred to the negative electrode, it is absorbed by the negative electrode, and the discharged sulfuric acid liquid will reoccupy the gas channel in the AGM separator until the bubbles generated on the surface of the positive electrode grow again to form a gas channel. Therefore, in the AGM battery, the gas passage from the positive electrode through the separator to the negative electrode may be unstable or discontinuous.In the AGM battery, due to the fact that after the sulfuric acid electrolyte is added to the separator, the assembly pressure is greatly reduced, and the surface of the electrode plate and the separator is uneven, so that there is always a relatively large gap between the electrode plate and the separator. The direct transmission of oxygen from the positive electrode to the negative electrode is difficult, so in AGM batteries, a considerable amount of oxygen is transferred vertically. Since the pore size of the polar plate is smaller than that of the AGM separator, more electrolyte is retained in the polar plate. The lead and negative electrodes on the side plates of the battery pole group are not covered with colloids, etc., and it is easy to form a three-phase interface of gas, liquid, and solid. In the AGM battery, the reaction between lead and anode and oxygen not only occurs on the surface between the positive and negative plates, but a considerable amount of oxygen circulation also occurs on the negative plates outside the pole group. The rapid recombination of oxygen on the side panel of the pole group also makes the total pressure of the gas chamber inside the battery lower than that of the gel battery. It is reported that stiffening strips on the inner wall of the battery tank can greatly increase the efficiency of oxygen circulation.Figure 11. AGM BatteryIn the study of the gel battery, it was found that in the gel battery, with the extension of the use time and the formation of micro-cracks in the colloid, the total gas chamber pressure in the gel battery is higher than the total gas chamber pressure of the AGM battery at equilibrium, vertical oxygen transmission in the direction is suppressed. In the gel battery, with the extension of use time, the silicone gel will dry crack, forming fine cracks, thereby forming a channel for oxygen to be transferred from the positive electrode to the negative electrode. In a gel battery in normal operation, since both the positive and negative plates are covered with gel, the oxygen compound reaction rate on the negative plate on the side of the pole group is extremely low. The compound reaction of oxygen on the negative electrode mainly occurs on the negative electrode plate corresponding to the positive electrode plate. That is, horizontal transmission is mainly used. Furthermore, in the gel battery, the electrolyte saturation has an important influence on the oxygen transmission mode. When the saturation is higher than 91.5%, the transmission mode is mainly vertical transmission; when the saturation is lower than 91.5%, mainly horizontal transmission. In the oxygen cycle of the gel battery, the transmission of oxygen in the vertical direction is slower than in the AGM battery; Compared with the AGM battery, the gel battery is more conducive to the horizontal transmission of oxygen. In the gel battery, since it is a gas channel formed by dry cracking of the gel, the gas transmission channel is basically stable. VI AGM vs. Gel Batteries: CostThe cost of gel batteries is higher than that of AGM batteries in terms of equipment, separators, and materials:First, the cost of equippment. In the production of gel batteries, not only the equipment for glue distribution but also the special equipment for glue filling is needed. Due to the use of gel electrolyte, the gelation phenomenon may occur due to the high viscosity of the gel electrolyte, so the production process control requirements are completely different from the production process of the AGM battery, the process is more complicated, and the technology is difficult to master.Second, the cost of separators. The gel battery uses a microporous plastic separator, which requires high porosity, good strength, and thin thickness. The cost of a high-quality microporous separator is relatively high. For AGM batteries, the separator is made of ultra-fine glass fiber, and the manufacturing process is relatively simple and the cost is low.Third, the cost of materials. The design margin of the electrolyte of the gel battery is generally larger. Not only does it increase the silicone gel material, it also requires more sulfuric acid electrolyte. The total weight of sulfuric acid electrolyte and silica gel is heavier and the material cost is higher.Therefore, the overall cost of the gel battery is high. As for AGM battery, the production process is relatively simple, the process is better controlled, and the battery is lighter, so the cost is lower than gel battery.Figure 12. AGM vs. Gel Batteries: CostVII ConclusionFrom the foregoing comparative analysis, it can be seen that AGM batteries and gel batteries are two types of batteries manufactured using different design ideas.For AGM batteries, AGM separators are used to fix the electrolyte, which is generally designed with a lean electrolyte and a tight assembly structure, which makes the battery lighter and has better large current discharge performance. Due to the low amount of acid, high-density sulfuric acid is required. The life span of AGM batteries is relatively short, and the manufacturing cost is relatively low.For the gel battery, it adopts a rich-liquid design, the amount of sulfuric acid electrolyte used is large, the density of sulfuric acid is relatively rare, the battery performance is more stable, the life span is longer, and the manufacturing cost is higher. VIII AGM vs.Gel Batteries QuizFigure 13. Quiz1. What is a gel battery?A gel battery (often referred to as a gel cell battery) is a lead-acid battery that is valve regulated. When the electrolyte is mixed with sulphuric acid and silica, it becomes a relatively stationary gel substance. 2. What is better AGM or gel battery?AGM batteries are comparably cheaper than Gel batteries, but they present a longer life span and offer bigger bursts of amps when needed. These batteries work best in high-power usage, such as sports vehicles. 3. What are the advantages of a gel battery?These types of batteries will operate effectively between an incredible -40 degrees Fahrenheit and 140 degrees Fahrenheit. Additionally, their gel make-up makes them better able to withstand corrosion, shock, and vibration. Slower discharging for a longer lifespan. 4. Is AGM a gel battery?AGM (Absorbed Glass Mat) and gel batteries are both examples of VRLA (Valve Regulated Lead-Acid) batteries. ... In common parlance, the term gel battery is used to indicate both AGM and Gel batteries. AGM batteries may also be called “membrane”, “starved electrolyte” or “dry” batteries. 5. Is an AGM battery worth the extra money?Definitely worth the price. The biggest perk is they hold their charge. You can charge it in the fall, come spring it's still 100% charged. I know mine has lasted quite a bit longer than my old lead batteries…that said, I never spent the money on lead then I now do on AGMS.

Ⅰ IntroductionLithium batteries are a type of battery that uses lithium metal or lithium alloy as the cathode material and use a non-aqueous electrolyte solution. Lithium battery is an ambiguous term. In 1912, lithium metal batteries were first proposed and studied by Gilbert N. Lewis. In the 1970s, M. S. Whittingham proposed and began researching lithium-ion batteries. Due to the very active chemical properties of lithium metal, the processing, storage, and use of lithium metal require very high environmental requirements. With the development of science and technology, lithium batteries (broadly speaking) have now become mainstream. CatalogⅠ IntroductionⅡ HistoryⅢ Li & Li-ion Battery Features3.1 Advantages3.2 DisadvantagesⅣ Lithium Battery VS Lithium Ion Battery4.1 Lithium Batteries4.2 Li-ion BatteryⅤ ApplicationⅥ Battery Security6.1 Battery Storage6.2 Charging Rules6.3 Battery ExplosionⅦ Development ProspectsⅧ One Question Related to lithium metal & lithium ion Battery and Going Further8.1 Question8.2 AnswerⅡ HistoryIn the 1970s, M.S. Whittingham used titanium sulfide as the positive electrode material and metallic lithium as the negative electrode material to make the first lithium battery.In 1980, J. Goodenough discovered that lithium cobaltate could be used as a cathode material for lithium-ion batteries.In 1982, R.R.Agarwal and J.R.Selman of the Illinois Institute of Technology discovered that lithium ions can be embedded into the graphite, which is fast and reversible. At that time, lithium batteries made of metal lithium have attracted much attention because of their safety issues. Therefore, people tried to embed lithium ions to graphite to make rechargeable batteries. Finally, first available lithium-ion graphite electrode was successfully trial-produced by Bell Labs.In 1983, M. Thackeray, J. Goodenough, and others found that manganese spinel is an excellent cathode material, which has good properties of low cost, stability, and excellent electrical and lithium conduction. Its decomposition temperature is high, and its oxidizing property is far lower than that of lithium cobaltate. Even if having a short circuit or overcharge, combustion and explosion can be avoided as far as possible.In 1989, A. Manthiram and J. Goodenough discovered that a positive electrode using a polymeric anion would generate a higher voltage.In 1991 Sony released the first commercial Li-ion battery. Subsequently, lithium-ion batteries revolutionized the development of consumer electronics. For example, the weight and volume of portable electronic devices such as mobile phones, notebooks, and calculators has greatly reduced.In 1996, Padhi and Goodenough discovered that phosphates with an olivine structure, such as lithium iron phosphate (LiFePO4), are more superior than traditional cathode materials, and  become the mainstream cathode materials gradually.Lithium batteries were first used in pacemakers. Lithium batteries have the advantages of low self-discharge rate and gentle discharge voltage, so that the pacemaker implanted in the human body can operate for a long time without recharging. Lithium batteries generally have a nominal voltage higher than 3.0V, making them more suitable as integrated circuit power supplies.To develop a new better lithium battery, various materials have been researched and tested. Ⅲ Li & Li-ion Battery Features3.1 Advantages1) High energy density. With high storage power density, it has reached 460-600Wh / kg, which is about 6-7 times that of lead-acid batteries. It is one of the major advantages of lithium ion battery technology. For example, high energy-dense 18650 cells can deliver over 3,000mAh and the costs have dropped further today.2) Long cycle life, the service life can reach more than 6 years. For example, the battery 1C (100% DOD) with lithium ferrous phosphate as the positive electrode is charged and discharged about 10,000 times.3) High rated voltage, a single battery working voltage is 3.7V or 3.2V, which is approximately equal to the series voltage of 3 Ni-Cad or Ni-MH rechargeable batteries, in addition, it is convenient to form a battery power pack. What’s more, lithium batteries can use a new type of voltage regulation technology to adjust the voltage to 3.0V to suit the use of small appliances.4) High power resistance capacity. For example, phosphate lithium-ion battery for electric vehicles can reach 15-30C charge and discharge capacity, which is convenient for high-intensity startup acceleration.5) Low self-discharge rate. It is one of the most outstanding performances of the battery, which can generally be less than 1% per month, and it is much lower than that of other rechargeable cells such as Ni-Cad and NiMH batteries.6) Light weight, about 1 / 6 to 1 / 5 of lead acid products under the same volume.7) Good performance at high and low temperature. For example, the battery can be used in the environment of -20 ℃ ~ 60 ℃, after processing, it can be used in the environment of -45 ℃.8) Less harm to environment. Regardless of production, use and scrap, it does not contain or produce any toxic and harmful heavy metal substances, such as lead, mercury, cadmium.9) There are several types available. It means that the right technology can be used for the special application required. 3.2 Disadvantages1) Lithium primary batteries have poor safety and risk of explosion.2) Li-ion batteries (lithium cobaltate) cannot be discharged at high currents.3) Li-ion batteries need protecting circuit to prevent the battery from being overcharged and over discharged.4) Li-ion batteries will only last two or three years from the date of manufacture whether you use them or not.5) High production requirements and costs.6) Limited use conditions, because they are extremely sensitive to temperature.7) As for air transportation/travel, many airlines limit the number of lithium ion batteries they take.Ⅳ Lithium Battery VS Lithium Ion Battery4.1 Lithium Batteries4.1.1 ChemistriesLithium batteries are primary batteries that have metallic lithium as an anode, and metallic lithium or other alloy metals used as cathode, regarded PP or PE film as the the separator.Note: Discharge reaction: Li+MnO2=LiMnO2They have low self-discharge rate, annual self-discharge can be ≤1%. The service life of fully sealed (metal welded, lazer seal) batteries up to 10 years, and semi-sealed batteries are generally 5 years.Lithium metal is used as the negative electrode, and the positive electrode and the electrolyte are thionyl chloride (sulfoxide). Cylindrical batteries have electricity after assembly. The voltage is 3.6V, which is one of the most stable types of batteries. It is suitable for use on electronic instruments and equipment that cannot be maintained frequently, providing subtle current. 4.1.2 Battery StructureLithium batteries usually come in two shapes: cylindrical and square. The inside of the battery is a spiral winding structure, and a very fine and highly permeable polyethylene film separator is used to separate the positive and negative electrodes. The positive electrode contains a current collector composed of lithium cobaltate (or nickel-cobalt lithium manganate, lithium manganate, lithium ferrous phosphate, etc.) and the aluminum foil. The negative electrode consists of a current collector composed of graphitized carbon material and the copper foil. The battery is filled with an organic electrolyte solution. It is also equipped with a safety valve and a PTC element (partially cylindrical) to protect the battery from damage during abnormal conditions and output short circuits. 4.1.3 Battery Material AnodeThere are many choices of anode materials, for example, LiFePO4 is mostly used as mainstream products.  Chemistry ReactionThe lithium ion is embedded when discharge, and de-embedded in the charge.On Charge：LiFePO4 → Li1-xFePO4 + xLi+ + xe-On Discharge：Li1-xFePO4 + xLi+ + xe- → LiFePO4 CathodeGraphite is commonly used, and new research has found that titanate may be a better material. Chemistry ReactionThe lithium ion is de-embedded when discharge, and embedded in the charge.On Charge：xLi+ + xe- + 6C → LixC6On Discharge：LixC6→ xLi+ + xe- + 6C Conductive CoatingThe conductive coating is also called pre-coating. In industry, it usually refers to a layer of conductive coating applied to the surface of the positive electrode current collector-aluminum foil. The earliest experiments on aluminum foil in batteries can be traced back to the 1970s. With the development of new energy industry, especially the development of LiFePO4 batteries, it has become a hot new technology in the industry.The conductive coating can effectively improve the adhesion of the pole pieces in the lithium battery, reduce the amount of binder used, and also significantly improve the battery's electrical performance:1) Contact resistance decreases 40%2) Adhesive reduces 50%3) Battery voltage increases 20%at the same magnification.Material and current collector adhesion increases 30%, and no delamination after long-term cycling.In addition, carbon coated aluminum foil is another coating which made of conductive carbon-based composite paste and high-purity electronic aluminum foil by transfer coating process. 4.1.4 Shell CharacteristicsTo improve safety and voltage, scientists have invented materials such as graphite and lithium cobaltate to store lithium atoms. The molecular structure of these materials forms nano-scale small storage lattices that can be used to storage. In this way, even if the battery case is broken and oxygen enters, the oxygen molecules will be too large to enter these small storage cells, so that lithium atoms will not react with the oxygen to avoid explosion.  4.2 Li-ion Battery4.2.1 TerminologyLithium-ion battery is a type of batteries with non-aqueous electrolyte that uses lithium alloy metal oxides as anode material, graphite as cathode material.Li-ion batteries currently include liquid lithium-ion batteries (LIB) and polymer lithium-ion batteries (PLB). Among them, the liquid lithium ion battery refers to a secondary battery whose Li + is compound. The positive electrode uses lithium cobaltate and lithium manganate, and the negative electrode uses a lithium-carbon interlayer compound. Li-ion batteries have advantages of high operating voltage, small size, light weight, high energy, no memory effect, no pollution, small self-discharge, and long cycle life. Note:Reaction on anode: LiCoO2==Li(1-x)CoO2+XLi++Xe-(electron)Reaction on cathode: 6C+XLi++Xe- = LixC6Total reaction: LiCoO2+6C = Li(1-x)CoO2+LixC6Its practicality has greatly reduced the weight and volume of portable electronic devices such as mobile phones and notebook computers, and the using time is greatly extended. Because lithium-ion batteries do not contain heavy metal cadmium, compared with nickel-cadmium batteries, the environmental pollution is greatly reduced. 4.2.2 Li-ion Battery Characteristics High energy densityThe weight of a Li-ion battery is half that of a nickel-cadmium or nickel-hydrogen battery of the same capacity, and the volume is 20-30% of a nickel-cadmium battery and 35-50% of a nickel-hydrogen battery. High voltageThe operating voltage of a lithium-ion battery cell is 3.7V (average value), which is equivalent to three nickel-cadmium or nickel-metal hydride batteries connected in series. Small pollutionLi-ion batteries do not contain harmful metal substances such as cadmium, lead, and mercury. No lithium metalLi-ion batteries do not contain metallic lithium, so they are not subject to the ban imposed by airlines of carrying lithium batteries in passenger aircraft. Long cycle lifeUnder normal conditions, the charge-discharge cycle of a lithium-ion battery can exceed 500 times, and a iron phosphate battery can reach 2000 times. No memory effectThe memory effect refers to the phenomenon that the capacity of the battery decreases during the charge and discharge cycle of the nickel-cadmium battery. Lithium-ion batteries do not have this effect. Quick chargeUsing a constant current & voltage charger with a rated voltage of 4.2V, the lithium-ion battery can be fully charged in 1.5 ~ 2.5 hours; and the newly developed lithium iron phosphate battery can be fully charged in 35 minutes. 4.2.3 Matters of UseKeeping lithium-ion batteries regularly charged and discharged can extend battery life. Lithium-ion battery power is maintained at 10% ~ 90% is better for the battery. This means that you don't need to reach 100% when charging batteries for digital products such as mobile phones and laptops. Under normal circumstances, 50% of the power is best for lithium-ion battery storage.When digital products equipped with lithium-ion batteries are exposed to sunlight or stored in hot cars, it is best to turn these products off because lithium-ion batteries will age faster if the operating temperature exceeds 60℃. 4.2.4 Li-ion Battery SelectionLi-ion batteries are divided into liquid lithium-ion batteries and polymer lithium-ion batteries. The electrolyte of a lithium-ion battery is fluid, so it is more unstable than a lithium polymer battery, and it may explode if it is hit by an external force or if a non-compliant charger is used. And now that the popularization of portable electronic products such as smart phones, e-books, tablets, and laptops uses batteries as a power source, battery hidden troubles will break out at any time. To prevent these, we must pay attention to the following:1) The capacity is clearly marked. Batteries without a clearly marked capacity (such as 1000mAh) are likely to be inferior or recycled.2) Standby time. It is the continuous use time from the time the battery is loaded to the next charge.3) Safety protection circuit board. Without it, the lithium battery is at risk of deformation, leakage, and explosion.Lithium Ion Vs Lithium Polymer BatteriesⅤ ApplicationWith the development of microelectronic technology, more and more miniaturized devices have been put forward, which places high requirements on power sources. Lithium batteries have subsequently entered a large-scale practical stage.The earliest application was lithium sub primary battery, used in pacemakers. Due to the low self-discharge rate and gentle the discharge voltage, this makes it possible to implant the pacemaker into the human body for long-term use.Lithium manganese batteries generally have a nominal voltage higher than 3.0V, which is more suitable for integrated circuit power supplies and is widely used in computers, calculators, and watches.Li-ion batteries are widely used in mobile phones, notebook computers, power tools, electric vehicles, street light backup power supplies, navigation lights, and small household appliances, which can be said to be the most popular type.Ⅵ Battery Security6.1 Battery Storage6.1.1 Lithium BatteryPrimary lithium battery can be discharged continuously or intermittently. Once the power is exhausted, it can no longer be used, and it is widely used in electronic products with low power consumption such as cameras. It has a low self-discharge rate and can be stored for up to 3 years. In addition, it is good to store lithium primary batteries in low temperature to get better storage.Note: Lithium primary batteries are different from lithium ion batteries, the former cannot be charged. 6.1.2 Li-ion BatteryAlso called secondary lithium battery. It can be stored for more than half a year at 20°C. This is due to its low self-discharge rate and most of its capacity can be recovered.The self-discharge phenomenon e4xists in lithium batteries. If the battery is stored below 3.6V for a long time, it will cause the battery to over-discharge and damage the internal structure of the battery, reducing the battery service life. Therefore, long-term storage of lithium batteries should be recharged every 3 to 6 months, that is, keeping the battery voltage at 3.8 ~ 3.9V, and it is appropriate to maintain the discharge depth at 40% ~ 60%. The battery should be stored in a dry environment at 4 ℃ ~ 35 ℃ or in a moisture-proof packaging. In addition, Keep away from heat sources and sunlight.Storage requirements: In the environment with a temperature of 20 ± 5℃ and a humidity of no more than 50%, the air and water vapor must be prevented from contacting the aluminum foil during transportation. 6.2 Charging Rules Charging voltageGenerally, the battery voltage of a mobile phone is 3.7V, but the voltage of a general charger is 5V, but it will not affect the use. Shallow charge and dischargeThis is more beneficial for lithium batteries. Only when the power module of the product is calibrated for lithium batteries, it is necessary to deepen and deep charge. Therefore, lithium-ion-powered products do not have to be constrained by the process. Overcharge and overdischargeThe rated voltage of a lithium-ion battery is generally 3.7V. Depending on different materials, the positive electrode of lithium iron phosphate is 3.2V. The international standard for termination charge voltage when fully charged is 4.2V, and iron phosphate is 3.6V. Overdischarge or self-discharge reaction at low voltage will cause decomposition and destruction of lithium active material, and may not be recovered. And any kind of overcharging of lithium-ion battery will cause severe damage to the battery performance and even cause explosion. Therefore, the lithium-ion battery must avoid overcharging during the charging process.6.3 Battery Explosion6.3.1 Explosions ExpressThe type of battery cell explosion can be summarized into three types: external short circuit, internal short circuit, and overcharge. Here, the “external” refers to the outside of the battery cell and includes short circuits caused by poor internal insulation design of the battery pack. When a short circuit occurs outside the battery cell and the electronic component fails to cut off the circuit loop, high heat will be generated inside the battery cell, causing some of the electrolyte to vaporize, which will expand the battery case.When the internal temperature of the battery reaches 135 degrees Celsius, a good quality separator paper will close the pores, the electrochemical reaction will be terminated almost, the current will drop suddenly, and the temperature will decrease slowly, avoiding the explosion. However, if the pore closing rate is too poor, or the separator paper with poor quality, the battery temperature will continue to increase, causing more electrolyte vaporize, and finally the battery case will be broken, even be exploded.The internal short circuit is mainly caused by piercing diaphragm by the burrs of copper foil and aluminum foil piercing the diaphragm, or dendritic crystals of lithium atoms.These tiny needle-like metals can cause micro-short circuits. The copper and aluminum foil burrs are caused during the production process, and the observed phenomenon is that the battery leaks too quickly, and most of them can be detected by the cell plant or assembly plant. Moreover, because the burr is small, it is sometimes blown out, which makes the battery return to normal. Therefore, this kind of explosion is less happened. Therefore, the explosion caused by the internal short circuit is mainly caused by overcharge.After overcharging, needle-shaped lithium metal crystals are everywhere on the pole pieces, piercing points are everywhere to make micro short circuits. Therefore, the temperature of the battery will gradually increase, and finally the electrolyte is vaporized at high temperature. In this case, whether the temperature is too high to damage electrode materials and the battery housing burns and explodes, both situations will cause an explosion.Based on the above types of explosions, we can focus on batteries protection in three aspects: overcharge, external short circuits, and improvement of battery safety.When designing a battery system, two electronic protections must be provided for overcharge, overdischarge, and overcurrent. Final protection method, the safety level of batteries, which can be roughly differentiated according to the ability to withstand short circuit and overcharge. In addition, before the battery explodes, if lithium atoms accumulate on the surface of the battery, the explosion power will be greater. Comparing the performance of aluminum shell cells with steel shell cells, aluminum shells have high safety advantages. Moreover, consumers use inferior chargers. Thus the ability of cells to resist overcharge is more important than the ability to withstand external short circuits. 6.3.2 Explosion Causes1) Large internal polarization2) The pole piece absorbs water and reacts with the electrolyte.3) The quality and performance of the electrolyte.4) The amount of injection does not meet the process requirements.5) Poor sealing performance during laser welding in assembly process.6) Manufacturing dust is easy to cause micro short circuit.7) The positive and negative plates are thicker according to technological requirements, and it is difficult to insert the case.8) Sealing problem of liquid injection, for example, poor sealing of steel ball causes air drum.9) The shell is too thick, and the deformation of the shell will affect the thickness.10) High external ambient temperature. 6.3.3 Protection MeasuresTo avoid over-discharging or over-charging due to improper use, a triple protection mechanism is provided in the single-cell lithium-ion battery. The first is the use of switching elements. When the temperature in the battery rises, its resistance value rises, if the temperature is too high, the power supply will automatically stop. The second is to choose an appropriate separator material. When the temperature rises to a certain value, micron-sized micropores on the separator will automatically dissolve, so that lithium ions cannot pass through, and the internal reaction of the battery stops. The third is to set a safety valve (that is, the vent hole on the top of the battery). When the internal pressure of the battery rises to a certain value, the safety valve will automatically open to ensure the safety of battery.Sometimes, although the battery itself has safety control measures, due to some reasons, for example, security control fails, or the lack of a safety valve, or the gas is too slowly to release through the safety valve, therefore, the internal pressure of the battery will rise sharply and cause an explosion.In general, the total energy stored in a lithium-ion battery is inversely proportional to its safety. As the battery capacity increases, the battery volume also increases, its heat dissipation performance becomes poor, and the possibility of accidents will increase significantly. For Li-ion batteries for mobile phones, the basic requirement is that the probability of a safety accident is less than one in a million. For large-capacity lithium-ion batteries, especially electric vehicles, the use of forced heat dissipation is particularly important.Choose a safer electrode material, for example lithium manganate material, to ensure that the molecular structure is fully charged, the lithium ions of the positive electrode have been completely embedded in the carbon pores of the negative electrode to avoid the generation of dendrites is fundamentally. At the same time, the stable structure of lithium manganate makes its oxidation performance much lower than that of lithium cobaltate, and the decomposition temperature exceeds 100 °C of lithium cobaltate. The danger of burning and explosion caused by the precipitation of metallic lithium is avoided when having short circuit or overcharge.After the lithium battery cell is overcharged to a voltage higher than 4.2V, side effects will begin to occur. The higher the overcharge voltage, the higher the danger. Because the number of lithium atoms remaining in the positive electrode material is less than half, at this time, the storage cell collapses, causing the battery capacity to permanently decrease. If you continue to charge, since the storage cell of the negative electrode is already filled with lithium atoms, subsequent lithium metal will accumulate on the surface of the negative electrode material. These lithium atoms will grow dendritic crystals from the surface of the negative electrode toward the lithium ions. These lithium metal crystals will pass through the separator paper, making the positive and negative electrodes short-circuit. Sometimes the battery explodes before a short circuit occurs.When at a  overcharge process, materials such as the electrolyte will vaporize, which will cause the battery case or pressure valve to swell and rupture, allowing oxygen to enter and react with the lithium atoms accumulated on the negative electrode surface.Therefore, when charging a lithium battery, the upper limit of the voltage must be set to guarantee the battery life, capacity, and safety. The optimal charging voltage limit is 4.2V. There is also a lower voltage limit when the lithium battery is discharged. When the cell voltage is lower than 2.4V, some materials will start to be destroyed. In addition, when the lithium battery is discharged from 3.0V to 2.4V, the released energy accounts for only about 3% of the battery capacity. Therefore, 3.0V is an ideal discharge cutoff voltage. When charging and discharging, the limitation of current is also necessary. If the current is too large, lithium ions have no time to enter the storage cell, and will collect on the surface of the material, which will affect the battery performance.After these lithium ions have obtained electrons, lithium atom crystals will be generated on the surface of the material, which will cause danger, like overcharge. Therefore, the protection of lithium-ion batteries must include: the upper limit of the charging voltage, the lower limit of the discharge voltage, and the upper limit of the current. In general, except the lithium battery cell, there is a protective plate in the lithium battery pack.Ⅶ Development ProspectsTo develop more excellent batteries, various materials have been studied. For example, lithium sulfur dioxide batteries and lithium thionyl chloride batteries are very characteristic. Their positive electrode active materials are solvents for the electrolyte. This structure made only in non-aqueous electrochemical systems. Therefore, the research of lithium batteries has also promoted the development of electrochemical theory of non-aqueous systems. Except the use of various non-aqueous solvents, polymer thin film batteries has also been studied.Lithium batteries are widely used in energy storage systems such as hydropower, thermal power, wind power and solar power, telecommunications, electric vehicles, military equipment, aerospace and other fields.Lithium-ion batteries have been widely used in portable appliances such as laptop computers, video cameras, and mobile communications due to their unique performance advantages. With the shortage of energy and environmental protection, lithium battery is widely used in the electric vehicle industry, especially the emergence of lithium iron phosphate material batteries, which has promoted the development and application of the lithium battery industry. Ⅷ Questions Related to Lithium & Lithium-ion Batteries1. Is a lithium battery the same as a lithium ion battery?Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again. 2. Do lithium-ion batteries need a special charger?Ultimately, using a battery charger with a specific Lithium charge algorithm is the best option for maximum performance and lifespan of any lithium battery. 3. Can you overcharge a lithium battery?In a lithium-ion battery, overcharging can create unstable conditions inside the battery, increase pressure, and cause thermal runaway. ... At best, this will lead to reduced capacity and shortened life cycle, and at worst this could cause thermal runaway. 4. Which is better lithium ion or lithium polymer battery?High powerBoth lithium-ion and lithium-poly batteries are suitable with high and robust power usages. However, lithium-ion batteries are more efficient and popular than lithium-polymer. They have higher energy levels and powers and are more suitable for heavy usages. 5. What is the difference between a lithium battery and a lithium-ion battery?Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again.

Ⅰ AbstractIn portable electronic devices such as mobile phones, notebook computers, and small video cameras, lithium-ion batteries have developed rapidly due to their sound performance, such as high working voltage, large specific energy, long cycle life, low self-discharge rate, no memory effect and so on, which are compared with traditional NiCd batteries and NiMH batteries.Figure 1. Lithium-ion Movement in Li-ion BatteryCatalogⅠ AbstractⅡ Charging Characteristics of Lithium BatteriesⅢ Performance Description of Several Different Charging States3.1 On Standby3.2 Precharging3.3 Constant Current3.4 Constant VoltageⅣ Charging Process Analysis4.1 High Voltage Constant Current Mode4.2 Low Voltage High Current Mode4.3 High Voltage High Current ModeⅤ Li-ion Battery Charging Security5.1 Common Sense in the Daily Use of Batteries5.2 Charging RulesⅥ One Question Related to Lithium-ion Battery and Going Further6.1 Question6.2 AnswerThe charge and discharge of lithium-ion batteries do not transfer electrons through traditional methods, but energy changes occur through the entry and exit of lithium ions in the crystals of layered materials. Under normal charge and discharge conditions, the in and out of lithium ions cause changes in the interlayer spacing, but will not cause damage to the crystal structure, so lithium-ion batteries can be regarded as an ideal reversible battery. During charging and discharging, lithium ions come and go between the positive and negative electrodes of the battery, and they shake between the positive and negative electrodes like a rocking chair.Lithium-ion Battery Charging BasicCharging batteries is common for people's daily life, as we all know, Li-ion batteries play a very important role in our social life with their excellent performance, in order to get longest service life, proper charging of Li-ion batteries is essential. Li-ion battery charging mode is voltage limit and constant current, which is controlled by IC chip. The typical charging method is: detect the voltage of the battery to be charged firstly, if its voltage is lower than 3V, pre-charge is required necessarily, and the the charging current is 1 ≤ 10 of the set current. After the voltage rises to 3V, then transferring into the standard charging process. The standard charging process is: having constant current charging with set current. When the battery voltage rises to 4.20V, it is changed to constant voltage charging mode, and the charging voltage is kept at 4.20V. At this time, the charging current gradually decreases till the current drops to 1/10 of the set charging current, the charging ends.The charging process of a Li-ion battery can be divided into three processes: trickle charging (low voltage precharging), constant current charge, and constant voltage charge. Ⅱ Charging Characteristics of Lithium BatteriesFigure 2. Typical Charge ProfileAs can be seen from the above figure, the charging current and voltage of the lithium battery are dynamically changed, which is determined by the chemical content of the lithium battery itself. Therefore, it is necessary to configure the performance of the charging IC according to the charging characteristics of the lithium battery itself to achieve a correct, safe and efficient use of the lithium battery. The "lithium-ion battery charging current" in the daily expression is for the charging current of fast charging. As a dynamic process, the optimal charging current of the lithium battery is actually divided into three stages. Ⅲ Performance Description of Several Different Charging StatesFigure 3. Li-ion Battery Process3.1 On StandbyThe standby state is handled in the following cases:1) The input voltage is lower than the minimum operating voltage of the circuit.2) After the battery voltage is approach to the limit.3) Using external switch to turn offmanagement IC to stop charge.Voltage and current characteristics in standby mode: The charging IC has no charging voltage output, and the IC input current is in the uA level, which can reduce power loss. 3.2 PrechargingAs shown in above figure. Optimal current during precharging: that is, when the initial/no-load voltage of the lithium battery is lower than the prechargeing threshold, it needs a pre-charging stage. For a single lithium-ion battery, this threshold is generally 3.0V, in the phase, the precharge current is about 10% of the current in the constant current charging phase. 3.3 Constant CurrentAs shown in the figure above, when the battery voltage is greater than the preset voltage threshold and less than the maximum voltage of 4.2V, the IC will charge the battery with the maximum charging current set by the external resistor. When the battery voltage is equal to the maximum charging voltage (near 4.2V), the charge stop.The best current for constant current charging: when stay in constant current stage, the voltage gradually rises, then enter the fast charging phase. Most of the constant current charging current is set between 0.5 and 1.0C, and the best set is 0.8C, because the battery can be full charged about two hours without consider other factors. The case is a good balance between charging time and charging safety.Several problems that should be paid attention to when batteries at constant current charging:1) In this state, the IC is in the state of maximum charging current, and the loss at this time is also the largest. The linear voltage drop loss calculation is L = (Vin-Vout) × Iout, it is necessary to pay attention to the maximum operating temperature of the IC.2) The increasing temperature due to the highest charging current, the IC will automatically reduce the maximum charge current, and this is why the charging current drops during overheating. 3.4 Constant VoltageThe maximum charging voltage portion shown in the above figure, when it is detected that the battery voltage is equal to or close to the battery charging voltage, at this time, the charging mode will be stepped down with a constant charging voltage of 4.2V. When it is detected that the charging current is less than 1/10 of the maximum set current, charging will stop. Charging current during constant voltage charging: In the case of a single-cell lithium-ion battery, as the battery voltage rises to 4.2 V, the constant current charging ends and the constant voltage charging stage begins. In order to achieve the best performance, the voltage stabilizer tolerance should be better than +1%.At this stage, the voltage is keeping constant and the current is reduced, and this current reduction is a sequential decrement process. Most lithium battery protection selects 0.1C as the termination current, which means that the charging process enters the end state. Once charging is finished, the charging current drops to zero. The problem to be noted in this state is that the battery can be automatically turned off when the battery is charged to the highest setting voltage. At the same time, when the overvoltage protection of the IC is in the abnormal battery state, it can be automatically locked. Unlike nickel batteries, continuous trickle charging is not recommended. Because it will cause plate plating effect to the lithium metal, making batteries failure.The core of the best charging current of lithium battery is the current design of constant current charging. It should be emphasized that most portable lithium batteries should be designed to charge 0.5C~0.8C. For example 1400mAh capacity of iPhone battery(capacity mAh= current mA × time /h), choosing 0.7C, that is, Apple’s charging current is about 1A, so that most of the batteries between 0.5C~0.8C you can choose.When charging, the voltage of the battery should be detected first. If the voltage is lower than 3V, pre-charging should be performed first. When the charging current is 1/10 of the set current, 0.05C is selected generally. After the voltage rises to 3V, it enters the standard charging process. The standard charging process is constant current charging with set current. Till the battery voltage rises to 4.20V, it is changed to constant voltage charging, and the charging voltage is kept at 4.20V. At this time, the charging current gradually decreases, and when the current drops to 1/10 of the set charging current, the charging ends.Generally, the charging current of the lithium battery is set between 0.2C and 1C. The larger the current, the faster the charging, and the greater the heat of the battery. Moreover, when lies in excessive current charging, the capacity is not full, because the electro-chemical reaction inside the battery takes time. Ⅳ Charging Process Analysis Figure 4. Charging Characteristics of Lithium-ion Battery 4.1 High Voltage Constant Current ModeIn general, the charging process of the mobile phone is to first reduce the 220V charging voltage to the 5V charger voltage, and the 5V charger voltage reduce to the 4.2V battery voltage. During the entire charging process, if the voltage is increased, heat is generated, therefore, the charger will heat up and the phone will heat up. Moreover, the greater the power consumption, the greater the damage to the battery. 4.2 Low Voltage High Current ModeWhen the voltage is constant, the current can be increased by using a parallel circuit. Under this situation, the smaller the volume shared by each circuit after parallel shunting, each circuit has the smaller load damage, so as to the phones charging process. 4.3 High Voltage High Current ModeThis method increases the current and voltage at the same time, so that from the previous formula P=UI, we can know that this method is the best way to increase the power, but it will generate more heat when the voltage is increased. In this way, the more energy is consumed, but the voltage and current are not freely increased without limitation.The maximum charging current of a lithium battery is strictly determined by the structure of the battery. Therefore, the specifications of the lithium battery manufacturers are not consistent, some are set to 0.6C, and the highest current specification for portable lithium batteries is 1C.  Of course, the current design of pre-charging and constant voltage charging cannot be ignored. In the two processes, if the initial voltage is not lower than the pre-charging threshold of 3.0V, there is no pre-charging process. In general, there is a process to check batteries charging voltage that is beneficial to keep the long-term use of lithium batteriess.Ⅴ Li-ion Battery Charging Security5.1 Common Sense in the Daily Use of BatteriesMisunderstanding: “Battery activation”, charging for more than 12 hours in the first three times.For the “activation” problem of lithium batteries, many sayings are: charging time must be more than 12 hours, and repeat three times in order to activate the battery. This statement that “the first three charges have to be charged for more than 12 hours” is obviously a continuation of nickel batteries (such as nickel cadmium and nickel hydride), in other words, this kind of statement can be said to be misinformation of the other batteries. After a sample survey, it conformed that a considerable number of people have confused the charging methods of the two batteries. Lithium-ion battery activation does not require a special method, they will be activated naturally in the normal use.The charge and discharge characteristics of lithium and nickel batteries are very different. All the professional technical data reviewed emphasize that overcharge and overdischarge can cause huge damage to lithium batteries, especially liquid Li-ion batteries. Therefore, charging is preferably performed in accordance with standard methods, especially for ultra-long charging of more than 12 hours. For example, the charging method described in the mobile phone manual is a standard charging method suitable for the mobile phone. It is not suitable to charge for a long time, also the battery is completely dischargedand thenThe lithium battery phone or charger will automatically stop charging when the battery is fully charged. There is no so-called “turbulent” charging over 10 hours for nickel battery chargers. If the lithium battery is fully charged, it will not be charged anymore continuously.Over-time charging and power off completely will cause over-charging and over-discharging, which will cause permanent damage to the positive and negative electrodes of lithium-ion batteries. At the molecular level, over-discharge will cause the anode carbon to release lithium ions excessively causing the layer structure collapses, and overcharging will hardly plug too much lithium ions into the negative carbon structure, and some of the lithium ions will no longer be released. Regular deep charge and discharge for battery calibrationLi-ion batteries generally have a management IC and a charge control IC. The management IC has a series of registers, which contain values such as capacity, temperature, ID, state of charge, and discharge times. These values will gradually change during use, so the main function of the “The batteries should be fully charged and discharged when used once a month or so” is to correct the improper values in these registers. 5.2 Charging RulesThe following rules should be noted when charging and discharging lithium ion batteries:Figure 5. Typical Li-ion Battery Discharging DiagramCharge currentItmust limited for li-ion batteries. Typically the maximum value is 0.8C, but lower values are more usually set to give some margin. Charge temperature  Itshould be monitored. The cell or battery must not be charged when the temperature is lower than 0°C or greater than 45°C. Short circuit protectionItis required to prevent damage or explosion as a result of short circuits. Over-voltage protectionItis required to prevent a voltage that is too high being applied across the battery terminals. Over-charge protectionItis required to stop the Li-ion charging process when voltage per cell rises above 4.30 volts. Reverse polarity protectionItis needed to make sure the battery is not charged in the wrong direction as this could lead to serious damage or even explosion. Over-discharge protectionItis required to prevent the battery voltage falling below about 2.3V dependent upon the manufacturer, when battery voltage less than 2.3V will make battery damage irreversibly. Over temperature protectionIt is necessary to prevent the battery operating in a high temperature, because heating will age batteries and reduce their service life. if the temperature rises too high. Temperatures above 100°C can cause irreparable damage.Ⅵ Questions Related to Lithium-ion Batteries1. How many years does a lithium ion battery last?three yearsThe typical estimated life of a Lithium-Ion battery is about two to three years or 300 to 500 charge cycles, whichever occurs first. One charge cycle is a period of use from fully charged, to fully discharged, and fully recharged again. 2. What is the difference between a lithium battery and a lithium ion battery?Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again. 3. Why are lithium ion batteries bad for the environment?Recycling Lithium-IonUnwanted MP3 players and laptops often end up in landfills, where metals from the electrodes and ionic fluids from the electrolyte can leak into the environment. Because lithium cathodes degrade over time, they cannot be placed into new batteries. 4. Is there a better battery than lithium ion?Zinc-air batteries can be considered superior to lithium-ion, because they don't catch fire. The only problem is they rely on expensive components to work. 5. What is the best way to charge a lithium ion battery?Simple Guidelines for Charging Lithium-based BatteriesTurn off the device or disconnect the load on charge to allow the current to drop unhindered during saturation.Charge at a moderate temperature.Lithium-ion does not need to be fully charged; a partial charge is better.

Warm hints: The word in this article is about 2800 words and  reading time is about 15 minutes.     Lithium-ion batteries can be said to be the most mature and widely used new energy sources in the world at present, such as portable electronic products like mobile phones and computers, electric vehicles, electric tools, and energy storage projects. Especially the current Chinese government and other countries are investing to support the development of new energy vehicles and power battery industries. Looking ahead, the lithium industry has a long way to go, such as the development of high energy density systems. The problems of further reduction of cost, the resources recovery, and the utilization are in front of us.   This article will mainly explain what is a lithium battery, then introduce the current situation and future development of lithium-ion battery materials.       Catalog I. What is A Lithium Battery? II. How Does the Lithium Battery Work? III. Distinction Between Lithium-ion Battery & Polymer Lithium Battery IV. Types and Characteristics of Material Used in Lithium Batteries V. Application of Lithium Battery VI. Future Development of Lithium Battery FAQ I. What is A Lithium Battery?   "Lithium battery" is a kind of battery that takes lithium metal or lithium alloy as negative electrode material and using a non-aqueous electrolyte solution. In 1912, lithium-metal batteries were first proposed and studied by Gilbert N. Lewis. In the 1970s, M.S. Whittingham proposed and began to study lithium-ion batteries.   Because of the active chemical characteristics of lithium metal, the environmental requirements of the processing, preservation, and use of lithium metal are very high. Therefore, lithium batteries have not been applied for a long time. With the development of science and technology, lithium batteries have become the mainstream now.   Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable. The fifth generation of rechargeable lithium metal batteries was born in 1996. Its safety, specific capacity, self-discharge rate, and the ratio of performance to price are superior to those of lithium-ion batteries, which are now produced by a few companies in only a few countries due to their own high-tech constraints.   Li-ion batteries are secondary battery system in which two different kinds of lithium intercalated compounds that can be inserted and removed as positive and negative electrodes respectively. When charged, lithium-ions are removed from the lattice of cathode materials. After the electrolyte is inserted into the lattice of the anode material, the negative electrode is rich in lithium, and the positive electrode is poor in lithium.   When discharged, the lithium-ion is removed from the lattice of the anode material, and then inserted into the lattice of the positive electrode material after the electrolyte, so that the positive electrode material is extremely rich in lithium while the negative electrode is poor in lithium. In this way, the difference between the potential of the cathode material and the lithium-ion when inserted and removed from the lithium metal is the working voltage of the battery.   Li-ion battery is a new generation of green high-energy battery with excellent performance and has become one of the key points in the development of high-tech.   Li-ion battery has the following characteristics: high voltage, high capacity, low consumption, no memory effect, no pollution, small volume, small internal resistance, less self-discharge, and more cycle times.   Because of the above characteristics, the lithium-ion battery has been applied to many civil and military fields, such as mobile phones, notebooks computers, cameras, digital cameras, and so on.   II. How Does the Lithium Battery Work?   The charging and discharging process of lithium battery is realized by the removal and embedding of lithium-ion in the positive and negative electrode of the battery. The reaction equation of the lithium-ion battery with iron phosphate liquid as an example is as follows:   Charging: Discharging:   The electrode reaction of Li/PEO-LiClO4/Pan polymer lithium-ion battery is as follows:   Positive electrode reaction: Negative electrode reaction： The working schematic diagram of lithium battery: Schematic-of-the-lithium-ion-battery-working-principle   1. The positive electrode structure:  LiMn2O4( lithium manganate ) + Conductive agent (acetylene black) + adhesive(PVDF) + Collector negative ( aluminium foil )electrode   2. The negative electrode structure:  Graphite+ Conductive agent (acetylene black) + adhesive(PVDF) + Collector negative ( copper foil )electrode   3. Charging process: The battery is charged by the power supply, and the electron e on the positive electrode runs from the external circuit to the negative electrode. Positive lithium-ion Li+ "jumps" from the positive electrode to the electrolyte, "climb" through the winding hole in the diaphragm, then "swim" to the negative electrode and combine with the electron.    The reaction on the positive electrode is: LiMn2O4 ==Li1-xMn2O4+Xli++Xe (electron).  The reaction on the negative electrode is:  6C+XLi+Xe==LixC6   4. Discharging process When the battery discharges, the electron e on the negative electrode runs from the external circuit to the positive electrode. Positive lithium-ion Li+ "jumps" from the negative electrode to the electrolyte, "climb" through the winding hole in the diaphragm, then "swim" to the positive electrode and combine with the electron.    The reaction on the positive electrode is: Li1-xMn2O4+xli++xe (electron) ==LiMn2O4 The reaction on the negative electrode is: LixC6 == 6C+xLi+xe III. Distinction Between Lithium-ion Battery & Polymer Lithium Battery   As the following table: Electrolyte for Polymer Lithium Battery PolymerElectrolytePure solid polymer electrolyteGel polymer electrolytePAn, PPY, PA, PPPPEO, PPOPAN,PMMA,PVdF   As the following diagram: Different electrolytes are the main differences between lithium-ion batteries and polymer lithium batteries. Diagram IV. Types and Characteristics of Material Used in Lithium Batteries (This is a tutorial on the Lithium Battery Explorer provides an overview of Li-ion battery technology and the properties that are relevant to battery researchers.)   1.Lithium manganate (LMO) LMO, as a kind of lithium battery material with a long history, has high safety, especially strong resistance to overcharge, which is a prominent advantage.   Because of the good structural stability of lithium manganate, the amount of cathode material does not have to exceed the negative electrode in the design of the electric core.   In this way, the number of active lithium ions in the whole system is small, and after the negative electrode is filled, there will not be too many lithium ions in the positive electrode. Even if overcharge occurs, there will not be a large number of lithium ions deposited in the negative electrode to form crystallization. Therefore, the overcharge resistance of lithium manganate is the best in common materials.   In addition, its material price is low, and the production process requirements are relatively low. It is a relatively early widely used cathode material.   But it also has obvious defects. The elevated temperature property of spinel lithium manganese oxide is poor. The existence of oxygen defect makes the core prone to capacity decay at the high voltage stage, at the same time, the cycle use at high temperature would cause a similar capacity decay. The reason is that the trivalent manganese ion which causes the disproportionation effect. The main way to prevent high-temperature attenuation is to reduce the trivalent manganese.   Lithium manganese, limited by its high-temperature performance, is generally not used in high-power or high-temperature environments, such as high-speed passenger vehicles, plug-in cars, and so on. But for electric buses, local logistics vehicles, and so on, lithium manganese is completely competent.     2. Lithium iron phosphate (LFP) The advantages of lithium iron phosphate are mainly reflected in its safety and cycle life. The main determinants are the olivine structure of lithium iron phosphate, which, on the one hand, leads to the lower ion diffusion capacity of lithium iron phosphate. On the other hand, it also has good high-temperature stability and good cycle performance.   The disadvantages of lithium iron phosphate are also obvious, such as low energy density, poor consistency, and poor low-temperature performance.     a) The low energy density is determined by the chemical properties of the material itself. A lithium iron phosphate macro-molecule can accommodate only one lithium-ion.   b)The consistency, especially poor batch stability, is related to not only the level of production management but also its own chemical properties. Lithium iron phosphate is one of the more difficult materials for the preparation of cathode materials for lithium-ion batteries.   The difficulty of consistency and uniformity in this chemical reaction raises another problem at the same time: The impurity of iron and iron in the lithium iron phosphate material always exists, which brings hidden trouble to the battery.   Lithium iron phosphate battery, because of its high safety, although The energy density part affects its range of use., but it is still the main power lithium battery variety of electric vehicle in our country at present, especially buses involving the safety of a large number of people, the national police enforce the use of lithium iron phosphate batteries.     3.Ternary lithium The ternary lithium cathode material synthesizes the advantages of LiCoO2、LiNiO2 and LiMnO2 and forms a synergistic effect within the same core. It combines three requirements of stability and activity of material structure and lower cost, which is one of the three main cathode materials with the highest energy density. The low-temperature performance is also obviously better than the lithium iron phosphate battery.    The higher the content of Ni in the three elements, the higher the energy density of the core and the lower the safety of the core will be. In practical application, the proportion relation of three kinds of materials in the electric core has been changing with the passage of time. The pursuit of energy density is higher and higher, so the proportion of Ni is higher and higher.   The most mentioned disadvantage of ternary material is safety. During the process of thermal runaway, the side reaction product contains a lot of gas, which greatly improves the risk of accident and the ability to spread.   Secondly, the cycle life of ternary materials is also a bottleneck, which has not reached the level of lithium iron phosphate. Last but not least, due to the special microstructure of ternary materials, it is not suitable for high-pressure compaction operation, thus the popular way to increase the energy density is not applicable to it.   The market share of ternary materials is gradually expanding, mainly driven by the pursuit of vehicle range. To catch up with or even surpass that of fuel vehicles, electric vehicles must have as much power as possible in a limited space.   This makes energy density particularly important. The improvement of the safety performance of the battery itself and the improvement of system monitoring and handling accident capability will also promote the expansion of the lithium ternary battery market.   V. Application of Lithium Battery   1. Lithium Iron Phosphate is the most suitable cathode material for Power Battery   After introducing the Types and characteristics of Lithium batteries above, now we will discuss about the most suitable cathode material for power supply.    Since 1996, when the Japanese NTT first exposed lithium iron phosphate cathode materials of olivine structure, John.B.Goodenough professor at Texas University also reported the characteristics of reversible intercalation and removal of lithium from LiFePO4 in 1997.   Since then, lithium iron phosphate has gradually become one of the low-cost, multi-element, and environmentally friendly cathode materials. Compared with traditional cathode materials, spinel LiMn2O4 of spinel structure and layered LiCoO2, the LiMPO4 of olivine structure is extremely stable.   The bond with oxygen is very strong, it will not explode because of the short circuit, the capacity is up to 170 mAh / g, the raw material is more extensive and the price is lower. Because of the similar structure of LiFePO4 and FePO4, the crystal structure of LiFePO4 has almost no rearrangement after the release/embedding of lithium-ion.   Therefore, LiFePO4 has better cycling performance, lithium-ion can enter and exit freely and can charge and discharge more than 1,000 times. It is also reported that lithium iron phosphate can be modified more than 10,000 times.   According to the following picture: Performance comparison of Lithium batteries with different cathode Materials.   Performance comparison Lithium iron phosphate is the most ideal cathode material at present. In comparison, the biggest problem of LiCoO is that it is easy to explode at a low temperature of 150C, and its cost is high (cobalt price is about 500,000 yuan/ton, and the price of LiCoO containing 60% cobalt will be over 400,000 yuan/ton). Also, it has a short cycle life.   The safety of lithium manganese oxide is much better than that of lithium cobaltate, but the cycle life in a high-temperature environment is even worse than that in a high-temperature environment(500 times).   With the advantages of high discharge power, low cost (about 18.3 million yuan/ton), rapid charging and long cycle life of more than 1000 times, the high stability of high temperature and high heat environment, and the good safety performance, lithium iron phosphate is the most ideal lithium cathode material for power vehicles.   At present, though the lithium iron phosphate battery is developing rapidly in China, there are several problems, including patent hidden trouble, low conductivity, and low capacitance, poor low-temperature performance, and low yield. VI. Future Development of Lithium Battery   Polymer Lithium Battery: one of the Future Development directions In addition to pure solid or gel polymer electrolytes, the principle and charge-discharge process of polymer lithium-ion batteries are consistent with those of liquid lithium-ion batteries.   Polymer lithium battery features include plastic flexible, more stable, safer, and less flammable, longer cycle life, higher energy density, high volume utilization(10-20% higher than lithium-ion batteries), no need to use traditional diaphragm materials, and easier for large scale production.   Polymer electrolyte is a kind of functional polymer material with ionic conductivity in solid-state which is formed by complexation of strong polar polymer and metal salt through acid-base reaction. Pure solid-state electrolyte dissolves lithium salts such as LiPF6, LiClO4, and LiBF4 in polymer bulk such as PEO and PPO as solid solvents. Gel electrolytes are electrolytes in a gel state by mixing more liquid solvents with polymer bulk.   Because there is no liquid flowing in the electrolyte, there is no leakage of the battery, so the problems such as burning and explosives are avoided. In order to reduce the thickness of the battery, a polymer lithium battery is usually packaged with aluminum plastic film with a thickness of only 0.1 mm, so it has a higher specific capacity than the ordinary lithium-ion battery.   FAQ   1. What is the difference between a lithium battery and a lithium ion battery? Lithium batteries feature primary cell construction. This means that they are single-use—or non-rechargeable. Ion batteries, on the other hand, feature secondary cell construction. This means that they can be recharged and used over and over again.   2. What are the disadvantages of lithium ion batteries? Despite its overall advantages, lithium-ion has its drawbacks. It is fragile and requires a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge.   3. Why is lithium ion the best battery? Li-ion batteries are able to be recharged hundreds of times and are more stable. They tend to have a higher energy density, voltage capacity and lower self-discharge rate than other rechargeable batteries. This makes for better power efficiency as a single cell has longer charge retention than other battery types.   4. What is the life of lithium ion battery? about two to three years. The typical estimated life of a Lithium-Ion battery is about two to three years or 300 to 500 charge cycles, whichever occurs first. One charge cycle is a period of use from fully charged, to fully discharged, and fully recharged again.   5. Is it good to fully discharge a lithium ion battery? Lithium-ion batteries should not be frequently fully discharged and recharged ("deep-cycled"). You may need to discharge it fully occasionally to recalibrate the capacitiy measuring electronics in the accumulator. Every 30 cycles or so should be enough.   6. How do I know if my lithium ion battery is bad? If the battery is dead or at the end of life, then it won't take charge anymore. If the battery is dead or at the end of life, the battery will swell a bit. The battery starts to heat up very quickly is also one of the indication that your battery is at the end of life.   7. Is there an alternative to lithium-ion batteries? Zinc-ion: A competitive alternative to lithium-ion for stationary energy storage. Lithium-ion batteries are the leading battery technology for both electric vehicles (EVs) and the renewable energy industry.   8. Do lithium ion batteries go bad if not used? Lithium Ion batteries "go bad" when they are stored in discharged state. It is all about battery voltage. If voltage is too low - undesireable chemical reactions will happen and battery will degrade. If battery is not empty and not used for long time - it will be fine.   9. What temperature is bad for lithium batteries? At temperatures above +60°C the Li-ion battery loses capacity constantly and thus performance capability.   10. At what voltage is a lithium ion battery dead? 3.4V. The voltage starts at 4.2 maximum and quickly drops down to about 3.7V for the majority of the battery life. Once you hit 3.4V the battery is dead and at 3.0V the cutoff circuitry disconnects the battery (more on that later. You may also run across 4.1V/3.6V batteries.     You May Also Like: How to Learn Analog Circuit Design Topological Materials are a Promising Material For Boosting Thermoelectric Generation Efficiency Use Polymer Films Material to Make Solar Cell Learn Some Basic Knowledge about Capacitor Voltage Transformer The First Full-Size IBC Bifacial Solar Module in the World