Non-uniform heat generation model of pouch lithium-ion battery based on regional heat generation rate

Abstract

The non-uniform distribution of temperature seriously affects the cycle performance, cycle life and safety of the pouch lithium-ion batteries. In this paper, a dynamic non-uniform heat generation model is developed to the high complexity and low precision of the modeling and characterization of dynamic non-uniform thermal characteristics of the pouch battery. Firstly, the regional heat generation rate of different regions is estimated by the particle swarm optimization based on the cell surface temperature to build a non-uniform heat generation model. Then, the battery's temperature distribution characteristics and heat generation distribution characteristics under the effect of ambient temperature, state of charge and discharge rate are analyzed. Furthermore, combined with the three-dimensional heat transfer equation, a three-dimensional heat model with non-uniform a heat source is modeled by COMSOL, the dynamic non-uniform temperature distribution of the battery is simulated at different ambient temperatures and discharge rates, and then the local temperature at any location of the battery is obtained. Finally, the simulated value of the local temperature is compared with the experimental value, and the average error under constant current discharge condition is less than 1 °C, and the relative error under dynamic current condition is less than 3 %. The result shows that the model can accurately estimate pouch lithium-ion batteries' dynamic non-uniform heat generation distribution under different working conditions.