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

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 custom-made 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.