Capacity Degradation Modeling and Lifetime Prediction of Lithium Battery in high temperature environments

Battery simulation models play a pivotal role in comprehending the intricacies of internal electrochemical reactions within batteries, thereby ensuring electric vehicle power systems' safe and efficient functioning. Among the numerous concerns, the prediction of battery lifespan and the comprehension of side reactions under extreme conditions are of paramount importance. This study aims to design an electrochemical model that considers multiple side reactions to predict the lifespan of lithium-ion batteries in high temperature environments. First, a basic simulation framework is established using an electrochemical-mechanical coupling model. Subsequently, through the disassembly experiment of aged batteries, five distinct types of secondary reactions are delineated, encompassing phenomena such as the cracking of negative electrode particle, the growth of solid electrolyte interphase (SEI), the oxidation of electrolyte and the decomposition/deposition of active materials. Building upon these elucidated aging mechanisms, a comprehensive battery lifespan prediction model is constructed by integrating multiple aging factors. 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.