Modelling of Lithium-Ion Battery Packs for the Prediction of their Thermal Degradation under Different C-Rates

This study aimed to develop a multi-physical model of Lithium-ion battery packs to assess their thermal performance and aging behaviour under various charge/discharge rates and environmental conditions, including ambient temperature and convective heat transfer coefficient. The Taguchi method was applied to identify the most critical operating conditions that influence the thermal degradation and assess the impact on battery capacity. The mathematical model was implemented in MATLAB/Simulink environment. The thermal performance and aging were evaluated based on the maximum temperature reached and the state of health, respectively. According to standard ISO 12405-2, the battery was considered to have reached the end of its life when its capacity declined to 80% of the initial value. The model predictions are consistent with expectations, demonstrating the capability to describe the problem's physics qualitatively. The results highlight the necessity of avoiding high ambient temperatures and excessive current rates to mitigate the risk of thermal runaway. Implementing appropriate thermal management systems, along with maintaining moderate charge/discharge rates, is recommended to extend the battery’s lifespan.