Comparative Evaluation of Phase Change Materials and Fins in Battery Thermal Management During High Discharge

Abstract

The rise of electric vehicles (EVs), driven by pollution-control policies, relies on lithium-ion batteries that face performance issues from temperature fluctuations. Thermal runaway remains a major safety risk, highlighting the need for efficient battery thermal management systems (BTMS). The present work numerically investigates the effectiveness of phase change materials (PCMs) and fins in BTMS performance. An 8-cell module operating at an 8C discharge rate was selected for analysis. ANSYS-based simulations were conducted to analyze the thermal behavior of prismatic battery modules under high discharge conditions. Both organic and inorganic PCMs were evaluated, alongside fins of varied geometry, orientation, and number. Results show that high thermal conductivity PCM, such as capric acid, lowered peak battery temperatures by 36 K compared to modules without cooling. Under natural convection, vertical fins were more effective than horizontal fins, whereas under elevated convective heat transfer coefficients (50 W/m²·K), horizontal fins achieved a 31 K reduction relative to no cooling. The combined effects of high thermal conductivity and specific heat capacity of PCMs were found to be critical for thermal regulation. Optimized PCM thickness outperformed fin-only configurations in overall effectiveness. However, achieving the right balance between fins and PCM remains essential for compactness and practical design integration. The advanced thermal management strategies improve battery safety and reliability and effectively address the United Nations Sustainable Development Goals.