圆柱形锂电池在局部压痕下的安全性实验研究

Experimental Study on the Safety Performance of Cylindrical Lithium-Ion Batteries under Local Indentation

锂电池局部挤压是汽车碰撞引发的主要损伤形式。为了明确锂电池在受到局部挤压时的安全性能,利用自研的机械滥用实验平台,对18650锂电池进行局部压痕实验,以渐进压缩的方式分析其失效过程,得到了失效过程及温度演变规律,讨论了电池荷电状态、加载速度、压痕位置和压头尺寸对电池安全的影响。结果表明:锂电池受局部挤压后有明显的热失控规律,失效后不会立即发生热失控,存在一定的反应时间;电池荷电状态与热失控剧烈程度成正相关,加载速度决定了电池的失效时间;靠近电池负极一端受到损伤时更易引发热失控现象,且受损面积较大时温度更高。实验结果可为锂电池包的安全性设计提供有益的建议。

Local compression of lithium-ion battery(LIB) is the primary form of damage during automotive collisions.In order to investigate the safety performance of 18650 LIBs under local indentation,a custommade mechanical abuse experimental platform was used to conduct local indentation experiments.The failure mechanism was analyzed through progressive compression,and the failure process and thermal runaway evolution rules were obtained.The effects of the state of charge(SOC),loading velocity,indentation position and indenter size on the safety performance of LIBs were also discussed.The results show that the batteries exhibit a clear thermal runaway pattern under local indentation,and this phenomenon will not occur immediately after the failure,there is a certain reaction time.The SOC is positively correlated with the intensity of thermal runaway,and the failure time of the battery depends on the loading velocity.Moreover,thermal runaway is more likely to occur when the negative electrode end of the battery is damaged,and the temperature is higher when the damaged area is larger.Finally,based on the experimental results,some useful suggestions for the safety design of the battery packs were provided.