Simulation Study on Stress-Strain and Deformation of Separator Under Battery Temperature Field

Abstract

Understanding the thermal stress, thermal strain, and deformation law of separators under a battery temperature field significantly improves battery safety. This article analyzes the temperature field distribution characteristics of an NCM523 soft pack lithium-ion battery under different discharge rates, and the thermal stress, strain, and deformation laws of the separator in the battery temperature field are evaluated through numerical simulation. The results show that the tabs have the lowest temperature in the battery, and the highest temperature is observed in the middle lower part of the center section of the cell. At a constant external temperature of 300 K and a discharge rate of 0.5 C, the maximum temperature of the battery at the end of discharge is 302.402 K. As the discharge rate increases, the maximum temperature of the battery gradually increases. The distribution of the thermal stress and thermal strain of the separator is related to the distribution of the battery temperature field; where the battery temperature is high, the thermal stress and thermal strain of the separator are large. The largest deformation of the separator occurs in the corner region. Moreover, with increasing discharge rate, the expansion of the separator increases.