锂离子动力电池系统热失控扩展特性试验研究

锂离子动力电池系统热失控扩展是造成电动汽车火灾事故的主要原因之一,文章以由圆柱形锂离子电池构成的动力电池系统为试验对象,采用加热触发单个电芯热失控的方式,通过采集电芯和模组的电压、温度等特征参数,对电芯热失控及在模组和系统范围内热扩展特性进行分析与研究。试验结果表明,电芯热失控诱发热扩展过程较为短暂,约5 s引发第二节电芯热失控;热失控发生前,触发电芯的负极采样温度高于正极,且负极温变速率平稳;热失控发生后,受正极喷射火焰影响,与之直接串接模组存在更高风险,在热扩展中受影响最大。

Research on Thermal Runaway Propagation Characteristics of Lithium Ion Battery System

Thermal runaway expansion of lithium-ion power battery system is one of the main causes of electric vehicle fire accidents.In this paper,the power battery system composed of cylindrical lithium-ion battery is taken as the test object.The thermal runaway of single cell is triggered by heating.By collecting the voltage,temperature and other characteristic parameters of cell and module,the thermal runaway and thermal expansion characteristics within the range of module and system are tested and analyzed.The results show that the process of thermal runaway induced by thermal runaway is short,only after 5 seconds the thermal runaway of the second core is caused.Before thermal runaway occurs,the sampling temperature of the negative electrode of the trigger cell is higher than that of the positive electrode,and the negative temperature rate is stable;after the thermal runaway occurs,the module directly connected with the positive electrode has higher risk due to the influence of the positive jet flame,and is most affected in the thermal expansion.