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Ⅰ IntroductionInvented by Boykin in 1959, resistors are today commonly used in almost all electronic circuits. Resistors can be described as a device that resists the flow of current flowing through itself, back when the resistor size was very huge and the tolerance value reached as high as 10 percent when it was implemented. Besides, they are usually made of compressed carbon. Resistors are mostly made from metal films and are available in small SMD packets with a tolerance value of as little as 2%, or even less, in the case of precision resistors. Carmet, KWK, Epcos India Pvt Ltd. and more are some of the leading manufacturers of resistors in India. If you didn't know, India accounts for some 34% of the market for passive components such as resistors by importing them, the remainder being imported. If you are interested in learning more about the work and characteristics of resistors, then you can try reading this article. We will address the difference between carbon film resistors and metal film resistors in this article.CatalogⅠ IntroductionⅡ Brief Intro to the ResistorsⅢ Carbon Film ResistorsⅣ Metal Oxide Film ResistorsⅤ Carbon Film Resistors VS Metal Oxide Film ResistorsⅥ Voltage and Temperature CoefficientⅦ SizeⅧ FAQⅡ Brief Intro to the ResistorsThe word "resistor" is born from the word "resist," meaning to withstand the impact. A resistor resists the movement of electrons that move through it, guides it, or controls it. With the support of the conductive material that it is made of, this is achieved. Now, the name makes sense, does it not? In parallel and series, resistors are connected according to the specifications for current and voltage. These small devices monitor, attenuate or decrease voltage and current, but do not have a power source of their own. The current flows through them in a controlled manner, resulting in a heat-like loss of energy. Only when there is a potential difference do two resistors bind and carry on a current between them. Yeah, they obey the Rule of Ohm. You must have heard, we're sure, of this statute. Oh, in the field of electronics and electrics, it is something to swear by. Moving on, depending on their characteristics, there is an infinite list of various types of resistors including composition form, film type, and wire-wound type of resistors. Physical size, durability, temperature rating, noise, temperature coefficient, and voltage coefficient, to name a few of these features. Well, the drill is known to you. We are here, however, to address two very significant types of resistors that are capable of transforming your electronic circuits.Ⅲ Carbon Film ResistorsLet us first contemplate what film resistors are before we begin talking about this. Well, after depositing oxide film or pure metals on a substrate or some insulating ceramic, these are simply those resistors that are formed. The layer is extremely thin and sputtering is known as the entire process. By depositing carbon film on the ceramic substrate that is an insulator, the carbon film resistor is prepared. The electric current is blocked by the carbon film to a certain degree. The insulating ceramic, on the other hand, does not allow heat to move through it, which in turn allows the carbon film resistor to withstand massive temperatures without being harmed. Carbon film resistors have a good tolerance rating, available from 1 ohm to 1 megaohm. Speaking of the resistance coefficient of negative temperature - the property of observing a decrease in resistance in response to a rise in temperature, these have a high coefficient of negative temperature that makes them susceptible to decreasing resistance as the temperature increases.These resistors are also available and have a very low tolerance at a low cost. They have a large variety of activities. Carbon film resistor applications are commonly used in X-Rays, power supplies and RADAR.Ⅳ Metal Oxide Film ResistorsMetal oxide film resistors use thin metal oxide films to coat an insulating ceramic rod, in contrast to carbon film resistors. Informing a coating film, the compound made from oxygen atoms and other atoms performs wonders. Using tin oxide, however, metal oxide film resistors are made. To produce better resistance, antimony oxide is also added. Because of the existence of an insulating ceramic rod that does not let heat pass through itself, these resistors are capable of withstanding high temperatures. Metal oxide resists the current at the same time. The greater the sum of antimony, the greater the resistance. But that doesn't even stop here, for good resistance metal oxide film resistors rely heavily on the thickness of the metal oxide and the width of the helical metal oxide film cut. The helical metal oxide film cut width and metal oxide thickness are inversely proportional to the resistance.Wondering what makes them special? Resistors come at a very low cost and withstand high temperatures while making much less sound. Also, along with high reliability and stability, they are small in scale.Ⅴ Carbon Film Resistor VS Metal Oxide Film ResistorWell, engineers are still in a dilemma about which to use one. Whether to use the resistor for the carbon film or the resistor for the metal oxide film. All right, let us break it down, bit by bit, for you. You want your experiments, after all, to go spot on. According to our contrast between Metal Film and Carbon Film Resistors, due to certain properties they possess that are listed below, we feel that metal-oxide film resistors prevail over carbon film resistors.Ⅵ Voltage and Temperature CoefficientThere are a stronger voltage coefficient and temperature coefficient for Metal Oxide film resistors than for carbon film resistors. The coefficient of voltage is the change in resistance concerning the change in voltage. In short, it is the ratio of the resistance change to the voltage change. Metal oxide film resistors operate in a wide range of resistors and can withstand a higher temperature than the resistors of the carbon film. Noise Design In contrast to carbon film resistors, metal oxide film resistors has a low noise design. They keep the minimum current. Therefore, it ensures less noise. If you didn't know, metal oxide film resistors, relative to carbon film resistors, make up for stronger resistors for radio frequency or high-frequency applications. Tolerance The 2 percent minimum carbon film resistor tolerance level does not stand a chance against metal oxide film resistors that can go as low as 0.1 percent.Ⅶ SizeFinally, compared to the carbon film resistors, the size of the metal oxide film resistors is smaller, making them a safer choice to go for. Now that we've done our bit to make you see the complexities of the resistors of both kinds, you can take your pick.Ⅷ FAQ1. What is a carbon film resistor?The resistive film deposited on the glass or ceramic rod is of pure carbon that is why they are called carbon film resistors. The thickness of the film will decide the value of the resistor. Spiralling is done on it in order to adjust the value of resistance.Some important features:• Tolerance =0.5% to 10%• Negative temperature coefficient of resistivity.• Wide temperature range from 55°c to 155°c• These are low power resistors typically of 1/8W, 1/4W, or 1/2W capacity. 2. What are the advantages of using metal film resistors versus carbon composition resistors?Metal film resistors produce less thermal noise than carbon composition resistors. Metal film resistors also typically have a much lower inductance/capacitance than carbon comp resistors so they (metal film) work better at higher frequencies. Carbon composition resistors have no real performance advantage over metal film resistors except that they are cheaper. 3. Are carbon film and metal film resistors interchangeable?No. They simply have less noise and do not drift in value. In short, they behave more like an ideal resistor. You can find metal films in 1% tolerance so the amps with those are very consistent in sound from amp to amp. 4. What is the advantage of a metal film resistor over a carbon resistor?The advantages that a metal film resistor has over a carbon composition resistor is that they don't change their value with age and their tolerance is better than the carbon resistor. 5. How do you identify a metal film resistor?Common carbon film resistors are mostly yellow or pink due to their low accuracy and low production costs, while most metal film resistors are blue. There is a layer of black protective paint on the surface of carbon film resistors, while metal film resistors are usually coated with bright white protective films. 6. What is the advantage of a metal film resistor?Metal film resistor has a low-temperature co-efficient of resistance. The rate at which the resistance of the material changes with a change in temperature is called the temperature coefficient of resistance. Metal film resistors have a low-temperature coefficient of resistance. 7. What is a carbon film resistor used for?The carbon film resistor is a type of fixed resistor that uses carbon film to restrict the electric current to a certain level. These types of resistors are widely used in electronic circuits. 8. Are metal film resistors inductive?Film resistors may be approximately classified as follows: values < 100Ω are inductive. values between 100Ω and 470Ω are practically true resistive. 9. What is a film resistor?Film Resistor is a general term referring to different types such as Carbon Film, Metal Film, and Metal Oxide Film resistors. They are generally manufactured by depositing pure metals (e.g., nickel) or oxide film (e.g., tin-oxide) onto an insulating ceramic or substrate. 10. What are carbon film resistors made of?Carbon film resistors are a fixed form type resistors. They are constructed out of a ceramic carrier with a thin pure carbon film around it, that functions as resistive material.

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.

ABOUT KNYIX OverviewKynix Semiconductor HongKong Limited was founded in 2008, which specializes in electronic components distribution business. With an experienced research and development,sales and management team, we have gradually established an excellent reputation and credibility in our international business. As our business philosophy, honesty and ethics are always in the first place when we serve our customers. For the accurate quotation, excellent credit, reasonable price, reliable quality, fast delivery, authentic service, we have won favorable comments of our customers.After years of steady development, Kynix has established good relationships of cooperation with well-known brand agents and manufacturers in Japan, Korea and some western countries (LG,INTEL,Foxconn,etc.). Also we have stable and good supply channels. At the meanwhile, we attach great importance to relationships with  everyone in this field, and cherish every opportunity of cooperation and sharing. Company profile Company nameKynix Semiconductor HongKong LimitedYear Established2008Area of BusinessElectronic components distributionAddress of companyFlat 08,4/F Shing Yip Ind Bldg,19,19-21 Shing Yip Street Kwun Tongkowloon Hong KongProductsOptical devices, embedded systems, semiconductors, circuit protection components, passive components, connectors, sensors, etc.ServicesOffering over 60 days after-sales services  Development History   Kynix’s Advantages    ·Our Operation SystemStrong enterprise management system, high intelligent procurement system, super stable order system, strong warehouse management system, professional inspection technology of professional shipment,convenient and efficient delivering system, applicable to PC/mobile devices. We are pleasure to serve for over 9000 clients around the world. We have spend 13 years to meet the needs from our worldwide clients and satisfy them, so we know clearly about the importance of safe delivery, timely after-sales service and  intimate service.           ·Warehouse ManagementWe strictly comply with the warehouse management rules. By implementing ERP system, we master the warehouse data accurately, which fundamentally ensure the accuracy and unity of actual operation, delivery status and the backend database.  At the same time, it further improves the working efficiency and accomplishes the scientific management of the warehouse.   Corporate Culture  Kynix is constantly committed to constructing a strong corporate culture and sharing its prosperity with all of its employees. Kynix is devoted to carrying out its core corporate culture of “honesty, efficiency and reliability”, adhering to the development concept of its quality culture under the theme of human-nurturing before goods-building and earnestness, etc. Close cooperation among departments plays a key role in a company’s operation. To ensure that all of our customers can get reliable and efficient service promptly, Kynix sales department always pays high attention to each RFQ sent by our customers and proceeds it in the first place. Our purchasing department is responsible for goods purchasing and quality assurance. Every staff in Kynix is trying their best to do their jobs well, which makes our company better and better.   Customers’ Reviews With the good cooperation, Kynix won a lot of praise from our customers. Follows are some reviews from them. “Both price and goods is suitable for my design! The seller’s service is really good! Anyway, I am indeed content with shopping of this time. Recommending Kynix strongly to everyone who wants to purchase electronic components.”——Nikita Silva “About one year ago I ordered a first shipment of parts from Kynix, so I′m giving a long-therm evaluation here. Kynix in my opinion is a reputable, professional supplier with great pricing, communication, care taking/handling and reassurance that no fake-parts are sold. I am very confident in their service and I′m currently preparing another shipment of same size......”——Florian Poeschko “Great seller, the best service.Very pleasant to deal business with such company.”——Crystal Ling “I placed a trial order in Kynix Semiconductor’s website, and I received the parts.They are all good and well packaged. The service is also excellent. I think I will but again!”——Madele “This is my second order. I got an excellent service and the delivery is very fast. I am very satisfied. Thank you.”——Gustavo “I am a regular customer of Kynix Semiconductor. After years of purchasing components here, I have to say these good points about it. And these are the reason why I want to recommend Kynix if you want to buy components for your design. Items: Standard, hard-to-get and long obsolete components like - Transistors (e.g. Sanyo 2SK44, Fairchild FQPF11P06) - Diodes (e.g. Rohm 1S2473, Toshiba 1S1588) - Integrated circuits (e.g. National Semiconductors LM308)  Quotation: The quotation (pre-buy) was turned around fast, it was accurate and clear (including shipping costs). Several parts needed communication on my behalf with a sales assistant who was able to answer every question I had (e.g. is component definitely from the manufacturer I specified, can I see another picture, etc.). All my necessities we′re met and all components/manufacturers could be found. Pictures were sent for confirmation where needed and matched parts sent.  Parts: After working with the parts over the past year I can say they are all of genuine brand/manufacturer and I haven′t yet had a single defective component.  Packaging: All parts were sent in sealed soft-bags/hard batch-casings and accurately labelled (part number, manufacturer and amount). Bags can be opened and sealed again which makes them great for both storage and regular use.  Shipment: The whole shipment was packed carefully and no damage to any parts. It was delivered faster as expected and customs were taken care of hassle-free. The cost was very reasonable.  Pricing: The pricing was excellent especially with greater amounts which was why I could purchase a greater amount for surplus (In some instances several hundreds of them.) I feel really good with their good quality and excellent service. Hope this evaluation can help you!”——Pinellis Sam   Kynix’s ProspectIn 2015, Kynix Semiconductor’s annual value of production had reached $50 million. And our partners in electronics field increased to 700 in 2016. Now the Chinese version of Kynix website is moving ahead and will be launched soon. ContactIf you want to know more about Kynix Semiconductor and our products, please view our website! Or you can contact us through our email: info@kynix.com. Come and buy good products at lower price from us!