12V27A battery

　　"Absolute safety" of 12V27A battery calls for innovative chemical solutions

　　Since the beginning of this year, mobile phone battery leakage and explosion accidents have occurred frequently. Among them, from July 8 to 25 alone, six such accidents occurred in various places. Previously, there were many reports of battery explosion accidents of electric vehicles at home and abroad. Industry experts pointed out that although overall, the accident rate of batteries is one in ten million, when it comes to human life, 12V27A battery cannot tolerate one accident.

　　At the second China Lithium Battery Electrolyte Seminar hosted by Asia Chemical Business Consulting Co., Ltd. in Shanghai recently, participating experts and entrepreneurs called for: In order to ensure the absolute safety of lithium battery production and use, domestic cooperation and joint development should be established. mechanism, increase investment in research and development, and strive to achieve breakthroughs in technology, engineering and materials through innovative chemical solutions.

　　The safety issue of 12V27A battery is a world-class problem that all countries are studying and solving. Judging from the structure of a lithium battery, it has a positive electrode, a negative electrode, a separator and an electrolyte, and its outer casing is all made of chemical materials. Li Yongkun, technical director of Guangzhou Tianci High-tech Materials Company, told reporters that the safety of 12V27A battery is directly related to these five parts, but the main cause of lithium battery deflagration is thermal runaway battery, and short-circuit heat release of the battery accounts for a large proportion. From the perspective of the electrolyte, the battery will generate heat during full discharge, and the electrolyte is composed of lithium salts, additives and solvents, especially solvents, such as ethylene carbonate, diethyl carbonate, etc., which will generate heat in a heated environment. Then the heat is released, causing the entire system to lose control. The industry generally believes that 150°C is the critical temperature for thermal runaway of lithium-ion batteries.

　　So, why does the heat of power lithium battery cause the battery to explode? He Xiangming, director of the Lithium Battery Laboratory of the Institute of Nuclear and New Energy Technology at Tsinghua University, said that tests proved that the battery explosion was caused by a short circuit within the battery. It expanded from one point to the entire battery, forming a chain chemical reaction and releasing huge energy before causing the accident. For example, battery separators are generally made of polyethylene or polypropylene materials, which will shrink in a heated environment, causing a partial short circuit between the positive and negative electrodes and releasing heat; in high-power power batteries, once the separator collapses and short-circuits, the voltage will drop. The temperature will quickly rise to 600°C, causing the positive electrode aluminum compound to burn violently and explode. He Xiangming said that foreign power batteries have now begun to use polyimide, which does not shrink at 180°C, as separator materials.

　　At the heart of battery safety is heat. Cutting off the heat-generating chain of the battery itself is an important measure to ensure battery safety. How to prevent thermal runaway of the battery, some experts proposed at the seminar that it can be solved from the two major directions of battery heat generation and heat transfer. The main measures include: using chemical materials with low heat dissipation; controlling the rate of exothermic reaction to reduce the rate of heat generation; increasing the temperature at which the exothermic reaction occurs; improving heat dissipation of the battery casing to alleviate battery temperature rise.

　　Guangzhou Tianci Company successfully developed a flame-retardant electrolyte last year. By adding flame-retardant materials such as fluorophosphoric acid esters, phosphazenes, fluoroborate esters and nitrile borane, the thermal runaway temperature of the battery was greatly increased; at the same time, it developed an ultra-low temperature electrolyte Electrolyte solutions include carboxylate esters (MA, EA), fluorinated solvents (FEA), etc. Power batteries using this material as electrolyte can be used in aerospace, special aircraft and other fields. Jiangsu East China Lithium Battery Technology Research Institute has recently developed gel electrolytes, etc., which greatly improve the oxidation resistance stability of the electrolyte. It not only has a high exothermic starting temperature and low heat dissipation, but also can alleviate the battery temperature rise, and can also prevent ordinary separators from being damaged. Oxidation prevents short circuits within the battery.

　　The tangle of polymer electrolytes is how to balance safety and electrical performance. In recent years, Tsinghua University Nuclear and New Energy Technology Research Institute and Jiangsu East China Lithium Battery Technology Research Institute have carried out research and development cooperation on the practical use of polymer electrolytes, and have embarked on a successful path from solid electrolytes to gel electrolytes and finally to composite electrolytes. , a series of results that can be industrialized have been formed. The composite electrolyte can not only meet the electrical performance of the battery, but also greatly improve the safety of the battery.

　　Professor He Xiangming of Tsinghua University said: The safety of my country's 12V27A battery has been greatly improved compared with many years ago, but safety is a complex and comprehensive technology, and it takes a process to completely overcome it. Nowadays, many domestic enterprises and scientific research institutes are optimistic about the lithium battery industry and have invested a lot of manpower, financial and material resources. However, they are fragmented, fragmented and constrained by cost and industrialization. It is recommended that the relevant government parties establish high-level industry-university-research cooperation. An innovative platform, organize collaborative research on key problems, give full play to superimposed advantages, achieve key breakthroughs, and jointly promote the technical safety of my country's 12V27A battery to a new level.

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