Low-cost and highly thermally conductive lauric acid–paraffin–expanded​ graphite multifunctional composite phase change materials for quenching thermal runaway of lithium-ion battery

The cooling role of phase change materials (PCMs) has emerged as a promising solution for battery thermal management systems (BTMS). However, issues such as high phase change temperature, low thermal conductivity, and easy leakage have been the long-term bottlenecks in the application of phase change materials. Herein, a composite phase change materials (CPCMs) is prepared by incorporating a mixture of lauric acid (LA) and paraffin (PA) with an expanded graphite (EG) thermally conductive unit. The mixture of lauric acid and paraffin provides latent heat, whereas expanded graphite enhances the thermal conductivity while preventing the leakage of lauric acid and paraffin. As expected, the lauric acid–paraffin–expanded graphite-based composite phase change materials demonstrate the high thermal conductivity of 1.22 W/(m k), the elevated melting enthalpy of 146.9 J/g, as well as the relatively low melting temperature of 36.1 °C. When used as a cooling system for battery thermal management systems, composite phase change materials can keep the maximum temperature of the battery below 43 °C with a temperature difference of 1.96 °C only, while ensuring the long-term cycling stability of the battery. Therefore, composite phase change materials with such a remarkable performance provide a promising and effective solution for battery thermal management systems.