Physics-Based Electrochemical–Thermal–Mechanical–Side Reaction Coupling Aging Model for Lithium-Ion Batteries

A physics-based electrochemical–thermal–mechanical–side reaction (ETMS) coupling aging model is proposed to describe the multiphysics coupling behavior during cycling of lithium-ion batteries (LIBs). First, the model revises the solid electrolyte interphase and lithium plating side reaction kinetics equations by using the electrode kinetics theory, taking into account the influences of material property and physical parameters such as concentration, current rate, and so on. In contrast to the unrevised model, it was found that the numerical results based on the physical model are more consistent with the experimental data. The physics-based side reaction model was coupled with the electrochemical main reaction process of the battery through physical parameters, which can better predict the capacity fade behavior of the battery over cycling. Meanwhile, the characteristics of the capacity fade in different stages of cycling was studied by analyzing the electrochemical behavior during cycling. Finally, the advantage of the physics-based ETMS model is that it can realize the investigation on the inhomogeneous aging induced by the non-uniform physical parameters distribution inside the battery. In this work, we used an ETMS model to demonstrate that high current rate charging accelerates the non-uniform side reaction processes. The findings in this model are of benefit to obtaining a profound understanding of aging behavior in LIBs and improving the applicability of the model in dynamic conditions. In addition, this model provides a wealth of physical parameter information during battery aging, which also has potential applications in assessing battery health and predicting remaining useful life.