Review on Numerical Analysis of Phase Change Materials for Battery Thermal Management Systems

Abstract: The rapid expansion of electric vehicles (EVs) has intensified the need for efficient battery thermal management systems (BTMS) to ensure safety, performance, and longevity of lithium-ion batteries. Phase Change Materials (PCMs) have emerged as a promising passive cooling solution due to their high latent heat storage capacity and cost-effectiveness. This review presents a comprehensive analysis of PCM-based BTMS, highlighting their advantages, limitations, and enhancement strategies. Key challenges, such as low thermal conductivity, are addressed through composite structures incorporating expanded graphite, biochar, nanoparticles, carbon nanotubes, and metallic coatings, as well as integration with fins for improved heat dissipation. Hybrid cooling systems combining PCMs with liquid cooling, air cooling, and heat pipes are discussed, demonstrating superior thermal uniformity and stability compared to standalone PCM systems. Numerical methods, including finite volume simulations, enthalpy-porosity, and apparent heat capacity approaches, supported by tools such as ANSYS FLUENT, COMSOL Multiphysics, and STAR- CCM+, are reviewed for their role in optimizing PCM-BTMS configurations. Results indicate that hybrid PCM systems significantly reduce maximum battery temperatures, enhance uniformity, and improve exergy efficiency, particularly under high discharge rates. The findings underscore the importance of material innovation, geometric optimization, and numerical modeling in advancing PCM-based BTMS for next-generation EV applications.