An Improved Resistance-Based Thermal Model for a Pouch Lithium-ion Battery Considering Heat Generation of Posts

Abstract An improved three-dimensional thermal model for a pouch battery is established, which seamlessly integrates two thermal sub-models of the battery body and the current collecting posts, taking the heat generated in both the battery and the current collecting posts into account. The thermal sub-model of the battery body considers the effects of the state of charge (SOC), battery temperature, and current rate on heat generation. The thermal sub-model of the posts is based on the identified post resistance and the contact resistance, which is employed to calculate the temperature evolution of the posts. Then, the thermal model is applied to predict thermal evolutions of the pouch Li-ion battery at different ambient temperatures and discharge rates. Extensive experiments are conducted to prove that the proposed model can accurately capture thermal behaviour under different conditions, with a maximum average error of 1.23 K. In addition, comparative studies show that this model significantly outperforms an existing typical counterpart, namely a model whose heat generation estimation only depends on the state of charge.