Study on the thermal runaway characteristics and debris of lithium-ion batteries under overheating, overcharge, and extrusion

As the use of lithium-ion batteries (LIBs) becomes more widespread in various fields, incidents of combustion caused by thermal runaway (TR) of LIBs are increasing. However, identifying the causes of TR is challenging. To address this, we employ a method that combines TR characteristics and debris analysis to identify the causes of TR in this study. We investigate a commercial LiFePO4 (LFP) battery and trigger TR under overheating, over-charge, and extrusion conditions. Following TR, we observe that under the overheating and overcharge condition, numerous floccule attach to the anode debris; under the extrusion condition, the anode debris is covered by numerous small particles; and under the overcharge condition, a large number of flocculant and smooth balls attach to the anode debris, and the composition of these substances contains numerous metal oxides. Moreover, under the overheating condition, the heat release, and gas release rate of the debris are the minimum, while they are the maximum under the extrusion condition. Due to the different reaction processes and degrees of TR under different conditions, the properties of the LIB debris also differ. By analyzing the debris and data, we can distinguish the debris under different conditions. This enables us to quickly identify the trigger factors of battery TR after it occurs.