Research progress of enhancing battery safety with phase change materials

Lithium-ion batteries (LIBs) are frequently employed in electric vehicles for their high energy density and lengthy cycle life. However, efficient battery thermal management system (BTMS) is critical for ensuring the reliability, safety, and service life, as temperature greatly impacts their performance. The potential risks of battery fire and explosion under excessive temperatures necessitate the development of effective emergency management and technologies to maintain safe operation. Phase change material (PCM) which offers distinct advantages, including reasonable cost, low energy consumption, and excellent temperature uniformity, making it an attractive candidate for thermal management, has emerged as a promising solution for BTMS. This comprehensive review aims to shed light on PCM-based BTMS, and it is found that carbon-based additives are better than metal-based additives concerning density and stability, and the addition of polymers and nanomaterials can improve the structural stability and mechanical properties. However, the flammability of PCM exacerbates the fire risk and hazard of battery thermal runaway (TR), and this review also has a particular emphasis on enhancing PCM's flame retardant properties and exploring its applications in BTMS. Flame-retardant PCM can ensure the safety of LIB utilization process and has a promising application in suppressing TR. Moreover, there exists a prominent challenge of the comprehensive need for optimization of heat dissipation optimization and improvement of TR propagation suppression ability of PCM-based BTMS. Finally, the challenges and outlooks focus on the future PCM-based BTMS are disclosed, in the hope of bring new insights to building a synergistic BTMS.