Flexible phase change materials obtained from a simple solvent-evaporation method for battery thermal management

In the advanced battery thermal management (BTM) strategy of phase change material (PCM) cooling, composite PCM (CPCM) is commonly obtained by a melting-blending method, which requires a preparation temperature as high as 150–200 °C to melt the polymer component. Herein, we prepare a new kind of flexible CPCM (FCPCM) through a simple solvent-evaporation method under room temperature by carefully selecting an ethylene-vinyl acetate (EVA) copolymer as the flexible polymer component. As prepared, the obtained EVA-based FCPCM possesses suitable thermo-physical properties and an excellent flexibility at room temperature, which can effectively reduce the thermal contact resistance, and therefore delivers an outstanding temperature-control performance in BTM applications. For example, during a harsh cyclic working environment, the battery module cooled by EVA-FCPCM plates shows a much lower maximum temperature and temperature difference at 50.0 and 3.7 °C, respectively, 8.1 and 4.8 °C lower than the battery module cooled by traditional rigid CPCM plates, respectively. This new and mild strategy adopting solvent-evaporation instead of melting-blending is believed to greatly simplify the preparation procedure, and thereby promotes the engineering applications.