Electrochemical–Thermal Coupled Modeling of Lithium-Ion Batteries for Cooling Performance Evaluation at Different Charge–Discharge Rates

Effective thermal management is essential for ensuring the safety, performance, and longevity of lithium-ion batteries (LIBs), particularly under high C-rate operation. This study develops a coupled 1D electrochemical–3D thermal–fluid model in COMSOL Multiphysics 6.2 to evaluate the thermal behavior and air-cooling performance of a cylindrical 18 650 LIB across multiple charge–discharge rates. Simulations quantify internal heat generation, temperature rise, thermal gradients, and cell potential variation, as well as cooling effectiveness at different inlet air velocities. Results show that increasing C-rate significantly intensifies heat generation and thermal non-uniformity, whereas higher airflow velocities markedly reduce peak temperature and improve uniformity. The integrated framework provides a reliable basis for analysing cooling strategies and guiding the design of thermally robust LIB systems.