Summary
The widespread use of lithium‐ion battery (LIB) urgently needs a thermal management system with excellent performance to manage it. Phase change material (PCM) has been adapted for thermal management of LIB because it can absorb a mass of energy without additional power. In this research, the thermal conductivity of PCM is improved, and its cooling effect is detected. The addition of hybrid thermal conductivity filler is beneficial to its uniform dispersion and improvement of aggregation phenomenon on the surface of materials. The results show that the PCM with hybrid filler has better thermal conductivity, which is increased by 264%. In different proportions of composite materials, the composite phase change material with 1% few‐layer graphene and 2% graphite nanoplatelet can play a better cooling effect in LIB module thermal management, and it respectively decreases the maximal temperature of the battery module by 7.17°C, 10.52°C, and 16.33°C at 1C, 2C, and 3C conditions, and the maximal temperature difference does not exceed the safety range of 5°C.