Influence of different causes on thermal runaway characteristic of LiFePO4 battery

To solve the current battery safety issues and accident investigation problems. Thermal runaway experiments triggered by nail penetration, hot box, flame heating and heating plate were carried out on a commercial 8 Ah pouch LiFePO4 battery. Recorded real-time phenomena, voltage and temperature. Then we discussed the TR process in the light of the latest mechanism study. The local TR is triggered by nail penetration within 3 s. The hot area above 700 degrees C and the spreading of internal TR was detected. LiFePO4 battery thermal runaway will generally emit white smoke, no fire. And it requires more attention to explosion risk. If the combustible gas is ignited, jet fire will appear, but the injection pressure is not extreme. Thermal runaway triggered by local heating is inconsistent with a voltage drop. A mapping method of thermal runaway parameters radar map is designed, which can indicate the danger degree of TR with shapes. Through comparison, some characteristics are obtained for the judgment of battery accident causes. This research can provide a basis for LFP battery safety evaluate and accident investigation.