Heat Transfer and Thermal Stress in a Lithium-Ion Battery

This paper presents a finite element based multi-scale model for a lithium-ion (Li-ion) battery cell. The model considers multi-physics including battery kinetics, diffusion, thermal and stress analysis. In battery thermal analysis, the heat source is critical. In this model, both resistive and entropic heating were considered. Simulations were carried out for a LiC₆/LiPF₆/Li_yMn₂O₄ cell under a discharge-charge cycle. The heat generations due to these two heat sources were compared. The thermal stress was computed and compared with the intercalation stress for individual battery components. Within the electrode particles, the thermal induced stress was negligible. In the separator, however, the thermal induced stress was comparable or even higher than the stress caused by intercalation deformation of the electrode particles.