Enhanced thermal safety and efficiency of battery modules using functional phase change composites

Phase change materials (PCMs) are widely used in battery thermal management (BTM) systems due to their high latent heat and passive cooling capabilities. However, conventional organic PCMs suffer from high flammability, leakage risks, and compromised thermal performance due to the addition of excessive flame retardants. In this study, an advanced functional polymeric (FP) framework with aliphatic side chains is developed to address these challenges. Benefiting from the extra latent heat of the FP framework, the designed composite PCM (CPCM) not only retains a high latent heat (106.3 J·g -1 ) despite a low PCM proportion (28 wt%), but also exhibits excellent leakage resistance and enhanced flame retardancy. The crosslinking structure of FP enables the proposed CPCM to achieve superior thermal flexibility, mechanical properties, and reduced dripping behavior compared to the classical epoxy-based CPCMs. Additionally, the synergistic flame-retardant mechanism of triphenyl phosphate and melamine plays a key role in char layer formation and gas-phase flame inhibition, significantly improving fire safety. This innovative design provides a promising multi-functional solution for battery thermal management and offers new insights into the development of high-performance flame-retardant PCMs for broader applications. • A functional polymeric phase change composite achieves simultaneous thermal regulation and fire safety in battery modules. • The crosslinked polymeric framework ensures shape stability and leakage resistance during repeated phase transitions. • A synergistic flame-retardant mechanism effectively suppresses thermal runaway propagation. • The design demonstrates a materials-driven strategy for safe and energy-efficient thermal management. • Provides a scalable route toward next-generation energy storage systems with improved safety and reliability.