A flexible phase change material based on hydrated salts exhibits high stability and insulation properties for battery thermal management

Abstract

Inorganic hydrated salts hold significant potential for battery thermal management due to their high thermal conductivity, substantial energy storage density, and low cost. However, challenges such as leakage, electrical conductivity, and rigidity hinder their broad application. In this study, hydrated salts were adsorbed into the pores of expanded graphite and subsequently encapsulated with silicone rubber to synthesize a novel hydrated salt composite phase change material. This composite exhibited high enthalpy, insulating properties, flame retardancy, and flexibility, making it suitable for lithium-ion battery thermal management. Test results demonstrated that with 40% silicone content, the phase change enthalpy of the composite material was approximately 98.2 J g⁻¹. This material possessed V-0 level flame retardancy and also exhibited good flexibility at room temperature. Its electrical conductivity was only 0.012 S m⁻¹. When applied to the thermal management of lithium batteries at a 3C charging rate, the surface temperature of the battery remained below 40 °C. The experimental results indicate that the prepared composite phase change material has potential value in battery thermal management, effectively maintaining stable battery temperature and enhancing thermal safety.