Electrochemical-Thermal-Mechanical Coupling Model Considering Lithium Plating for Multi-Stage Constant Current Fast Charging of Lithium-ion Batteries

Lithium plating has been identified as the main form of failure in fast charging, so it is imperative to develop effective methods for detecting lithium plating. Experimental results validated the effectiveness of lithium plating detection via expansion force measurement. While multi-stage constant current (MCC) charging is a common form of fast charging, experimental investigations of lithium plating under MCC charging remain scarce, particularly lacking models to describe the battery expansion force changes during the lithium plating process under MCC conditions. The expansion of batteries during charging is caused by factors such as intercalation reactions, thermal expansion, and lithium plating. Through the establishment of the coupling model, the expansion displacement of the battery is calculated. The thermal expansion coefficient and equivalent stiffness of the battery are obtained through experiments, which are used to calculate the battery expansion force. Additionally, the battery overpotential is calculated through the model to determine the impact of lithium plating on the expansion force. The model investigates the effects of lithium plating on battery expansion force under different C-rates during constant current and MCC charging processes, achieving semi-quantitative prediction of battery expansion force under MCC charging and providing model-based optimization directions for MCC charging strategies. This work provides valuable insights for battery modeling and charging strategy optimization in terms of expansion force modeling under multi-stage constant current charging.