Experimental study of Numerical Analysis of Phase Change Materials for Battery Thermal Management Systems

Abstract: This research paper presents an experimental and numerical study of Phase Change Materials (PCMs) integrated into Battery Thermal Management Systems (BTMS) for lithium-ion batteries. The escalating demand for electric vehicles (EVs) and portable energy storage systems necessitates effective thermal regulation strategies to ensure battery longevity, performance, and safety. Thermal runaway, capacity fade, and uneven temperature distribution are critical challenges that conventional cooling systems often fail to address adequately.

In this study, a comprehensive numerical model is developed using Computational Fluid Dynamics (CFD) and the enthalpy-porosity method to simulate the thermal behavior of PCM-based BTMS under various charge-discharge cycles. Paraffin wax (RT44HC) is selected as the PCM due to its favorable thermophysical properties, including a melting point of 44°C and a high latent heat of fusion of approximately 255 kJ/kg. The experimental setup consists of a battery module comprising six prismatic lithium-ion cells (LiFePO4, 20 Ah) encased in an aluminum housing filled with PCM.

Experimental results are validated against numerical predictions, demonstrating close agreement with a maximum deviation of 4.7%. The PCM-based system successfully maintained battery temperatures below 45°C during 2C discharge rates, reducing the maximum temperature rise by 38% compared to natural convection cooling. Furthermore, temperature uniformity improved by 52%, enhancing battery cycle life. Design calculations, material selection criteria, and manufacturing processes for the prototype are detailed. The findings confirm that PCM-based BTMS is a viable passive cooling solution for next-generation EV battery packs.

Keywords: Phase Change Material (PCM), Battery Thermal Management System (BTMS), Latent Heat, Lithium-ion Battery, Thermal Runaway, Numerical Analysis, CFD, Enthalpy-Porosity Method.