Abstract <p>The increasing energy demands of lithium-ion batteries (LIBs) in high-performance applications, such as electric vehicles and energy storage systems, have intensified the need for efficient thermal management strategies. In this study, a comparative thermal analysis of phase change material (PCM) and hybrid PCM-based battery thermal management systems (BTMS) is conducted to evaluate their effectiveness in regulating battery temperature and mitigating thermal runaway risks. A commercial lithium manganate pouch battery is considered, with its thermal conductivity and specific heat capacity measured using the planar heat source and calibrated calorimetric methods, respectively. The study employs three-dimensional transient numerical simulations using ANSYS Fluent 19.2, incorporating a grid independence study to ensure computational accuracy. The BTMS consists of a network of liquid cooling plates (LCPs) with spiral and serpentine channels, flow distributors, and a coolant system. The performance of PCM-based and hybrid PCM-based BTMS is analyzed in terms of maximum temperature reduction, temperature uniformity, and heat dissipation efficiency. Key parameters such as specific heat (1238 J/(kg K)) and thermal conductivity (11.1 W/(m K)) perpendicular, 18.1 W/(m K) parallel) are considered to optimize the cooling system. The results indicate that hybrid PCM systems exhibit superior thermal performance by maintaining battery temperatures within safer operating limits while enhancing heat transfer efficiency. The findings of this research contribute to the development of advanced BTMS solutions for next-generation LIB applications, ensuring improved battery lifespan and safety.</p>