3D Simulation Study on Thermal Behavior and Thermal Stress of Lithium-Ion Battery

Temperature and thermal stress are crucial factors affecting the working performance and thermal safety of lithium-ion batteries (LIBs). During the discharge process of the battery, the temperature increases. The thermal expansion stress caused by the entropy heat and the ohmic heat can lead to the battery's lifetime reduction and even thermal safety issues. Herein, based on the coupled electrochemical model, the LIB's thermal behavior and thermal stress distribution at a 1C discharge rate are simulated and analyzed. The results show that the temperature distribution inside the battery is mainly affected by the heat exchange surface and the position of the tabs during the discharging process, in which the localized high-temperature region occurs in the positive tab. The thermal stress inside the battery enhances rapidly at both the beginning and end of the discharging process while increasing slowly in the middle.