Phase change materials in thermal management of Li-ion batteries: A state-of-the-art review

The widespread adoption of lithium-ion batteries (LIBs) in electric vehicles, portable electronics, and renewable energy systems has intensified the demand for effective thermal management strategies to ensure safety, performance, and longevity. Among emerging solutions, phase change materials (PCMs) have attracted significant interest for their passive thermal regulation capabilities, particularly their high latent heat and isothermal behavior. However, the research landscape is fragmented, with varied materials, configurations, and integration strategies explored across the literature. This review aims to provide a comprehensive synthesis of recent advances in PCM-based battery thermal management systems (BTMS), highlighting their thermal performance, structural innovations, and hybrid configurations with active cooling methods. Drawing on experimental, numerical, and theoretical studies, the review identifies key design parameters affecting efficiency, including PCM composition, nano-enhancements, encapsulation techniques, and system architecture. The review examines emerging research trends such as the use of machine learning for BTMS optimization, development of multifunctional PCMs with flame-retardant and structural properties, and cost-benefit analyses supporting commercial viability. Despite notable progress, challenges remain in material stability, scalability, and integration complexity. This review concludes by outlining future research directions, including the standardization of performance metrics, exploration of bio-based PCMs, and adaptive control strategies.