Cause Analysis of Thermal Runaway Failure in LFP Battery Energy Storage System under Overheating Condition

This paper focuses on an industrial and commercial outdoor ground-mounted energy storage system composed of 280Ah LFP (Abbreviation for LiFePO4) batteries. The thermal runaway and thermal propagation characteristics of LFP batteries caused by heating under the condition of 100% SOC is studied. A flame ionization detector and a palladium-nickel alloy sensor were used to measure the concentration changes of THC, CO, CO2, O2 and hydrogen inside the energy storage system during the thermal runaway process. The test results showed that the cells close to the heat source will undergo thermal runaway first, followed by thermal propagation between the cells. If flammable gas generated when the cells undergo thermal runaway accumulates in the energy storage system, it is easy to cause the fire hazard. Reducing the concentration of flammable gases inside the energy storage system and improving the maximum operation temperature of insulating materials would help to prevent the risk of fire and explosion.