18650 li ion battery

　　18650 li ion battery technology debate: Should we develop ternary lithium batteries or lithium iron phosphate batteries?

　　18650 li ion battery technology debate: Should we develop ternary lithium batteries or lithium iron phosphate batteries? Looking at the current domestic new energy vehicle market, the main materials for electric vehicle battery technology are lithium iron phosphate and ternary lithium batteries. Some people believe that in the field of passenger cars, ternary lithium batteries are currently the most popular due to their high energy density and strong endurance. mainstream development direction. In the field of public transportation, we should stick to the lithium iron phosphate route with higher thermal stability and more secure safety.

　　18650 li ion battery technology debate: Should we develop ternary lithium batteries or lithium iron phosphate batteries?

　　The so-called lithium iron phosphate battery refers to a lithium-ion battery using lithium iron phosphate as the positive electrode material. The characteristic of this type of battery is that it does not contain precious metal elements. Since it does not contain precious metal materials, the raw material cost of lithium iron phosphate batteries can be reduced very low. In actual use, lithium iron phosphate batteries have the advantages of high temperature resistance, strong safety and stability, low price, and better cycle performance.

　　The ternary 18650 li ion battery refers to a 18650 li ion battery that uses lithium nickel cobalt manganate as the positive electrode material and graphite as the negative electrode material. Unlike lithium iron phosphate batteries, the ternary 18650 li ion battery has a very high voltage platform, which means that at the same time In terms of volume or weight, ternary lithium batteries have greater specific energy and specific power. In addition, ternary lithium batteries also have great advantages in terms of high-rate charging and low-temperature resistance.

　　Lithium iron phosphate batteries are characterized by high safety, high rate charge and discharge characteristics and long cycle life. Its charge and discharge characteristics are also relatively stable. The stability under high-rate discharge conditions is related to the performance of electric vehicles under high power demand conditions such as rapid acceleration and high speed. The more stable the voltage, the better the vehicle performance. In addition, this It can also explain why the battery life of electric vehicles is reduced when driving at high speeds, and the actual discharge capacity of the battery is reduced when the battery outputs high power.

　　Lithium iron phosphate batteries also have good fast charging characteristics. In addition to long life and excellent charge and discharge performance, the biggest advantage of lithium iron phosphate batteries is their safety. Lithium iron phosphate has stable chemical properties and good high temperature stability. 700- It will only start to decompose at 800°C, and will not release oxygen molecules when faced with impacts, needle sticks, short circuits, etc., will not cause violent combustion, and has high safety performance.

　　The disadvantage of lithium iron phosphate batteries is that their performance is greatly affected by temperature. Especially in low-temperature environments, the discharge capacity and capacity will be greatly reduced. In addition, the energy density of lithium iron phosphate is low. The weight energy density of the battery alone is only 120Wh/kg.

　　Ternary 18650 li ion battery refers to a 18650 li ion battery containing three elements: nickel, cobalt and manganese, with a transition metal-embedded lithium oxide conforming to the positive electrode of the material. This material combines the advantages of lithium cobalt oxide, lithium nickel oxide and lithium manganate. A three-phase eutectic system of three materials is formed, and its comprehensive performance is better than any single combination compound due to the ternary synergistic effect. The weight energy density can reach 200Wh/kg.

　　However, the safety of ternary lithium batteries is poor. Ternary lithium batteries have poor thermal stability and will decompose at 250-300°C. When encountering flammable electrolyte and carbon materials in the battery, the heat generated will further intensify the decomposition of the positive electrode and cause the cathode to decompose in a very short time. Will explode.

　　Due to safety considerations, new energy buses using ternary lithium batteries cannot be included in the new energy vehicle catalog of the Ministry of Industry and Information Technology, while cars and trucks are not affected. Although there are safety concerns, due to policy regulations on energy density, ternary lithium batteries have shown a tendency to replace lithium iron phosphate batteries and become the mainstream of passenger cars.

　　Compared with lithium iron phosphate batteries, ternary batteries have the advantage of higher energy density. With the rapid development of the electric vehicle market, people have higher and higher requirements for energy density. The cruising range has almost become the most important measure of the technical level of pure electric vehicles. Key indicators. Previously, China's power battery technology route was dominated by lithium iron phosphate batteries. However, the country's policy subsidies for new energy vehicles have also begun to tilt towards capacity density and cruising range.

　　At present, most battery factories are still in the process of developing high-nickel ternary batteries. Of course, a considerable number of car companies are preparing to acquire lithium iron phosphate battery materials in order to reduce costs and avoid competition. But no matter which one it is, for consumers, as long as the performance of the product is improving day by day without affecting safety, it is a good thing. Of course, the shares of ternary lithium and lithium iron phosphate batteries will not be much different, and the possibility of coexistence will be greater in the future.

　　The market competition between lithium iron phosphate and ternary lithium batteries is still evenly divided, each with its own strengths. With battery technology constantly changing and innovating, it is expected that revolutionary changes will come in the near future. Technology has already Mature ternary lithium batteries and lithium iron phosphate batteries have a place in the market with their respective advantages.

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