18650 lithium 3.7 battery

　　New technology makes power batteries more energy-efficient

　　“Only by ensuring the safety and reliability of materials can safe and stable power batteries and electric vehicles be made.” Li Jianzhong, director and general manager of Beijing Dangsheng Material Technology Co., Ltd., expressed the importance of 18650 lithium 3.7 battery materials.

　　With the development of new energy vehicles, breakthroughs in 18650 lithium 3.7 battery material research and development technology continue to occur, and new battery materials and new high-performance battery products continue to emerge. What is the current progress in research on high specific energy materials? What is the development trend of power batteries in the future?

　　High nickel ternary materials are still the mainstream

　　At present, new energy vehicles mainly use lithium-ion batteries, which are mainly composed of four parts: positive electrode material, negative electrode material, separator and electrolyte. Among them, the positive electrode material is the key to improving battery performance. According to the different materials used, it is divided into lithium titanate , lithium cobalt oxide, lithium manganate, lithium iron phosphate, lithium nickel cobalt manganate (NCM) and lithium nickel cobalt aluminate (NCA). NCM and NCA are commonly known as ternary lithium batteries.

　　Due to the relatively low energy density of lithium titanate batteries and lithium manganese oxide batteries, and the poor safety of lithium cobalt oxide batteries, ternary lithium batteries and lithium iron phosphate batteries stand out and rank among the new energy passenger car market and the passenger car market respectively. mainstream status.

　　Industry insiders pointed out that NCM batteries are mainly developed domestically, while NCA batteries are mainly produced by Japanese and Korean companies. "Judging from the current materials, ternary lithium batteries have developed from the original 333, 523, and 622 to the current 811, and are constantly updated and upgraded." Li Jianzhong said.

　　The numbers mentioned by Li Jianzhong refer to the ratio of nickel, cobalt and manganese in the battery cathode material. The "811" battery is a ternary lithium battery with nickel, cobalt and manganese in a ratio of 8:1:1.

　　The higher the nickel content, the greater the room for increasing the energy density of power batteries. "High-nickel ternary materials are still the mainstream trend, and the highest nickel content of NCM811 has reached 88%." Li Jianzhong said, "By increasing the proportion of nickel, not only can the energy density of the battery be increased, but the use of cobalt can also be reduced, to a certain extent. It alleviates the cost pressure caused by rising material prices." In addition, the "811" battery can also effectively solve the problem of battery lightweight, and is superior to ordinary ternary batteries in terms of space saving and other aspects.

　　He Wei, director of the technical department of Yiwei Lithium Energy Co., Ltd., said that lithium-ion batteries with higher energy density and lower cost will be the core needs of car companies. For the demand for endurance capabilities of more than 500 kilometers, they continue to be optimistic about ternary high-energy-density materials. ; For the demand for endurance capacity below 350 kilometers, we are optimistic about lithium iron phosphate batteries in the medium and short term.

　　Battery thermal stability continues to improve

　　As the "heart" of electric vehicles, the safety of power batteries and materials has always been the focus of attention from all parties.

　　For ternary batteries, the nickel content continues to increase, and the cobalt and manganese content used to stabilize the structure decreases accordingly, and the stability of the battery will also be greatly reduced. In this regard, Li Jianzhong said that there are still many technical solutions for ternary material batteries that need to be verified, but with technological iterations, 18650 lithium 3.7 battery materials have been significantly improved in terms of design, process improvement, process doping and processing, and the thermal stability There has also been a big improvement, and the peak heat release of the "811" battery has reached 220-230°C.

　　The reporter learned that modification of cathode materials is an effective measure to improve the thermal stability of battery materials. There are two commonly used modification methods. One is surface coating, which reduces the reaction between the active material and the electrolyte, while reducing the oxygen released during overcharging of the positive electrode material, which plays a role in stabilizing the matrix material; the other is The purpose of doping modification is to improve the structural stability of the material, thereby improving the material cycle performance. At present, 18650 lithium 3.7 battery companies such as BAK Battery, Lishen Battery, Penghui Energy, and Far East Foster are actively developing ternary materials, proposing solutions in coating, doping and other aspects to develop high capacity, long cycle life, and safety. Positive and negative electrode materials are used for power batteries with good performance.

　　Li Jianzhong pointed out that for power batteries, safety is a system issue and does not only depend on a certain aspect of the material's performance. All aspects of materials, battery design and preparation are closely related to the safety performance of power batteries. Problems in any of these links may bring safety hazards to power batteries.

　　New battery products continue to emerge

　　In the context of the "new four modernizations" of automobiles, range anxiety, safety anxiety and cost anxiety have forced 18650 lithium 3.7 battery and industry chain companies to continuously explore new directions based on existing material systems. Solid-state batteries and fuel cells are among them.

　　Recently, the "New Energy Vehicle Industry Development Plan (2021-2035)" (draft for comments) released by the Ministry of Industry and Information Technology shows that "implement battery technology breakthrough actions, carry out research on key core technologies such as positive and negative electrode materials, electrolytes, and separators, and strengthen Research on the shortcomings of high-strength, lightweight, high-safety, low-cost, and long-life power batteries and fuel cell systems, and accelerate the research and development and industrialization of solid-state 18650 lithium 3.7 battery technology, is listed as a "core technology research project for new energy vehicles."

　　"Our country has been able to achieve domestic production of key components of hydrogen fuel cell systems, such as stacks, catalysts, membrane electrodes, bipolar plates, sealing materials, etc., but the industrial chain for large-scale and mass production has not yet been fully formed, and the cost Higher." Li Jianqiu, a professor at Tsinghua University, talked about the current development status of fuel cells. Industry experts point out that hydrogen fuel cells are more suitable for long-distance large-scale, high-speed heavy-duty vehicles (heavy trucks, logistics vehicles, buses, etc.) and will mainly replace diesel engines.

　　Solid-state batteries take into account both safety and mileage advantages, and are being favored by domestic and foreign companies: Ganfeng Lithium Industry's annual solid-state lithium battery pilot production line with an annual output of 100 million watt hours has been officially put into production, and Weilai and Huineng Technology have cooperated to create solid-state battery packs Prototype cars, U.S. Department of Energy funds allocated for the research and development of solid-state batteries... Experts say that solid-state batteries are not perfect, and there are still some key issues to be overcome, such as low rate performance, slow charging speed, lack of electrolyte materials, etc.

　　The reporter noticed that new 18650 lithium 3.7 battery products on the market include cobalt-free batteries, quaternary batteries, etc. Regarding the development of new 18650 lithium 3.7 battery materials and new technologies in the future, He Wei said that from an industrialization perspective, there are two evaluation dimensions for new 18650 lithium 3.7 battery materials and new technologies. The first is technological maturity, with good technical direction and technological maturity. Only high-quality products have industrial promotion value; secondly, application value, such as high-nickel materials or NCA, which have nearly 10 years of application experience in motorcycles, power tools, etc., and will be applied to new energy vehicles when mature. The development of any technology must be gradual and down-to-earth.

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