Optimized thermal management and safety assurance with flame-retardant phase change materials for lithium-ion batteries

Lithium-ion batteries, integral to electric vehicles and energy storage systems, encounter significant thermal management and safety challenges. In light of these issues, this study developed a multifunctional phase change material (PCM) with enhanced flame-retardant properties for application in battery thermal management systems (BTMS). The PCM demonstrated good cyclic stability, retaining a high phase change enthalpy value of 93.68 J/g after 50 cycles. Cone calorimeter tests revealed that the peak heat release rate of the PCM was 64.3 % lower than that of pure polyethylene glycol, with a total heat release reduction of 32.7 %, and the PCM exhibited self-extinguishing behavior, achieving the UL-94 V-0 flame retardancy rating. Its thermal conductivity and thermal diffusivity were 2.73 W/(m·K) and 1.00 mm 2 /s, respectively, effectively enhancing heat dissipation efficiency. In battery thermal management experiments, the PCM effectively kept the maximum battery temperature below 45 °C across a range of ambient temperatures from 25 °C to 35 °C and discharge rates from 1C to 2C, maintaining battery safety. This study offers novel perspectives on the design of flame-retardant materials for BTMS and an effective approach to enhancing battery thermal management and safety.