Coupled Electrochemical-Thermal-Mechanical Modeling and Simulation of Lithium-Ion Batteries

In this paper, a generalized pseudo three-dimensional (P3D) electrochemical-thermal-mechanical coupling (ETM) model is proposed to describe the multiphysics coupling behavior during the discharge of lithium-ion battery (LIB). The proposed model is established and simulated by using COMSOL Multiphysics. In particular, the influence of external loads on the LIB is investigated via the stress field where the particle scale is coupled with the representative volume element (RVE) scale. Moreover, dynamic parameters dependent on the temperature and the lithium concentration are introduced to enable the proposed model more physically realistic. We validate the model by comparing the numerical results with experimental data available in the literature. In addition, we find that the lithium concentration gradient is reduced by the stress effect inside the active particles. Then, we show the distributions of stress and lithium concentration in the electrodes during the discharge process. Finally, the effect of external loads on the electrochemical process is investigated. It indicates that the electrochemical reaction is promoted. The results are of benefit to obtain an in-depth understanding of the stress mechanism, the lithium transport mechanism, and the synergistic mechanism among the multiphysics fields during the operation of LIBs.