Numerical Investigation of the Heat Generation Characteristics of Lithium Iron Phosphate Battery Under Penetration

Abstract

In this work, penetration tests are conducted on 20Ah prismatic LFP batteries with different SOCs, and the slow release of Joule heat and side reaction heat of LFP batteries under penetration are simulated by combining thermal model and parameter optimization. The results show that the 100% SOC LFP battery not only releases Joule heat, but also releases side reaction heat under penetration. About 56.4% of the electrical energy stored inside the battery is released in the form of Joule heat, which accounts for the majority of the total heat generated by the 100% SOC LFP battery, while the side reaction heat accounts for only 6.4%. What's more, the exothermic side reactions of 100% SOC LFP battery under penetration are effectively suppressed when the electrical energy release ratio is less than 0.52 or the convection coefficient between the battery and its surroundings is greater than 12 W·m-2·K-1.

Keywords: LiFePO4 battery, penetration, Joule heat, side reaction heat, simulation