摘要
通过分析近10年发生的典型锂离子电池安全事故,归纳总结了引发锂离子电池安全事故的因素、不同激源的作用机制以及燃烧爆炸机理。引发锂离子电池安全事故的因素主要包括:撞击、高温、挤压、外部短路和部件故障。根据作用机制的不同,引发电池安全事故的因素可以归为三类:机械激源、电激源和热激源。锂离子电池燃烧爆炸与电池的产热和散热相关。当锂离子电池产热速率大于散热速率时,电池内部出现热量积累,温度升高。随着温度不断升高,依次发生固体电解质膜(SEI)分解、负极和电解质反应、隔膜融化、正极分解和电解质分解等反应,电池内部产生大量高温高压可燃气体,壳内压力不断增大。当内部压力超过壳体的可承受极限时,壳体破裂,伴随高温高压可燃气液混合物的喷射和可燃气体的爆燃。
Based on the statistical analysis of typical lithium ion battery safety accidents occurred in the past 10 years,the factors triggering the safety accidents of lithium ion batteries, the mechanism of different excitation sources and the mechanism of combustion and explosion were analyzed. The results show that the main factors leading to the safety accidents of lithium ion batteries include impact, high temperature, extrusion, external short circuit and components failure. According to the mechanism, the factors can be classified into three categories: mechanical source, electric source and heat source. The combustion and explosion of lithium ion battery is related to the heat generation and heat dissipation rate of the battery. When lithium ion battery heat generation rate is greater than the dissipation rate, the heat accumulate with the temperature rising. The solid electrolyte membrane(SEI) decomposes,anode reacts with electrolyte, anode melts, separator and electrolyte decomposes. The reactions inside the battery produce high-temperature and high-pressure combustible gas with the pressure of shell increasing. When the internal pressure exceeds the ultimate strength of the shell material, the battery will rupture with high temperature and high pressure gas injection and the mixture of flammable gas deflagration.
引文
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