Simulation of thermal behavior evolution in lithium-ion pouch cells using a coupled reaction-thermal-expansion model

Conventional lithium-ion battery thermal simulation methods establish a coupled heat generation/transfer model to calculate the temperature evolution for hard-pack cells. However, the thermal behavior evolution of a pouch cell includes multi-processes such as heat generation, gas production, heat transfer, and pouch expansion. There is currently a lack of computational models for predicting the multi-state parameter evolution in temperature and pressure. In this paper, an efficient and accurate thermal behavior simulation algorithm for lithium-ion pouch cells is developed. A heated/exothermic two-stage hypothesis for the thermal behavior evolution in pouch cells was established under thermal abuse conditions. Analytical models of exothermic reaction, heat transfer and pouch expansion were formulated and integrated into a unified thermal behavior analysis framework. The proposed algorithm simulated the thermal behavior evolution in four commercial lithium-ion pouch cells. The computational and experimental results showed the calculation errors of the cell temperature and gas volume for the four samples were less than 3% and 5%, respectively. In terms of efficiency, the calculation time of the algorithm is within milliseconds. The accuracy and efficiency of the proposed algorithm are verified.