Failure and Microstructure Characteristics of Lithium Batteries under Different Overcharging Voltage Conditions

As lithium batteries become more and more widely used, the fire of lithium batteries is becoming more frequent. According to the investigation, most lithium battery fires are caused by overcharge. In order to research the failure and metallographic characteristics of lithium battery under different overcharge voltage. This paper simulates the process of overcharge battery fires by setting different charging voltages and using muffle furnace heating. The temperature changes and experimental phenomena of the battery during the experiment is recorded, and the positive electrode cap of the battery was subjected to metallographic analysis to compare the failure and metallographic characteristics of the lithium battery under different charging voltages. The results show that the explosion of lithium batteries is uncertain under overcharge. The higher the charging voltage, the higher the heating rate of the batteries, the larger the grain size of the positive electrode cap and the clearer the grain boundary. This study provides a way of thinking for the investigation of fire accidents of lithium battery, and lays a foundation for further research on the identification of fire traces of lithium battery.