Enhancing Lithium-Ion Battery Performance With Phase Change Material–Fin Pairings: A Numerical Study

Abstract

Abstract. 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 behavior of cylindrical cells integrated with PCM and aluminum 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 electric vehicle (EV) and stationary energy storage applications.