Electrochemical Modeling and Degradation Analysis of Lithium‐Ion Batteries in High Temperature Environments

ABSTRACT Simulation models are of great importance in understanding the complexities of the internal electrochemical processes within batteries, aiding in design optimization and advancing energy storage technologies. One of the central challenges lies in predicting battery lifespan and elucidating side reactions under extreme operating conditions. This study aims to design an electrochemical model that considers multiple side reactions to predict the cycle life of lithium‐ion batteries in high temperature environments. First, a basic simulation framework is established using a simplified electrochemical‐mechanical coupling model. Subsequently, multiscale characterization of aged batteries is performed to identify five types of side reactions, encompassing phenomena such as solid electrolyte interphase (SEI) growth, cracking of negative electrode particles, electrolyte oxidation and decomposition/deposition of active materials. A comprehensive battery life prediction model is constructed by modeling these side reactions. Finally, the accuracy of the life prediction is validated using high temperature cycling data. The conclusions reveal that electrolyte decomposition and the loss of active material are the primary causes of battery degradation under high temperature conditions.