Experimental investigation on hydrated salt phase change material for lithium-ion battery thermal management and thermal runaway mitigation

To efficiently ensure the suitable temperature for lithium-ion batteries, battery thermal management system based on phase change material (PCM) have gained considerable attention. A shape-stabilized composite PCM was prepared using the mixture of Na2SO4·10H2O and KAl(SO4)2·12H2O hydrated salts as phase change substrate, expanded graphite as thermal conductive filler and open-cell polyurethane foam as support material. The composite PCM containing 4 wt.% expanded graphite displayed a satisfied phase change temperature of 30.8 °C and 69.8 °C, high latent heat of 226.9 J/g, and good thermal conductivity of 1.39 W/(m·K). Meanwhile, it obtained a low subcooling degree, good leakage resistance, and excellent flame retardancy properties. Under PCM cooling in sandwich structure, during 0.5C charging and 1.5C discharging cycles, the maximum temperature and maximum temperature difference of battery were 52.47 °C and 2.20 °C, decreased by 20.4 % and 59.7 % respectively compared with nature air cooling. Furthermore, the composite PCM could significantly relieve the thermal runaway propagation between lithium-ion batteries. This work provides a feasible design and application strategy of hydrated salt based PCMs for battery thermal management and thermal runaway mitigation.