Enhancing Lithium-ion Battery Performance with Phase Change Material-Fin Pairings: A Numerical Study

Excessive heat generation in lithium-ion batteries during high C-rate operation can accelerate degradation, reduce efficiency, and compromise safety, underscoring the need for effective thermal management strategies. Phase change material (PCM)-based passive battery thermal management systems (BTMS) are attractive due to their latent heat storage capability; however, their low thermal conductivity necessitates enhancement techniques such as fins. In this study, a three-dimensional numerical model employing the enthalpy-porosity method is developed to examine the thermal behaviour of cylindrical cells integrated with PCM and aluminium fins. Both plate and pin fin geometries are systematically investigated at thermal conductivity enhancer (TCE) fractions of 4.78 %, 9.55 %, and 14.33 %, and additional simulations are performed for varying fin thickness at constant volume fraction. A performance metric, termed the “enhancement ratio,” is introduced to relate thermal conduction improvement to PCM endurance. Results indicate that pin fins with 9.55% volume fraction and 1 mm thickness achieve the most effective balance between heat transfer enhancement and latent heat storage, enabling extended safe operation under high C-rates. The findings provide practical design guidelines and a quantitative framework for optimizing PCM-fin structures in advanced BTMS in elective vehicle (EV) and stationary energy storage applications.