A novel flexible composite phase change material with enhanced toughness and shape stability for battery thermal management

The application of flexible composite phase change materials (FCPCM) in the thermal management of batteries has been widely studied. However, flexible materials can sometimes tear, so improved toughness and morphological stability are required. In this work, a new stable flexible composite phase change material, with good toughness is prepared, which is composed of paraffin, Styrene Ethylene Butylene Styrene (SEBS), Olefin Block Copolymer (OBC) and Expanded Graphite (EG). The thermal properties, toughness, morphological stability, and other properties of the fabricated FCPCMs are tested, and battery thermal management experiments are conducted to explore its thermal management potential. The results show that the elongation at break are about 150 % and 240 % of the FCPCM at the same temperature with OBC as the supporting material at 25 °C and 40 °C, respectively, which shows good toughness. It can still maintain a stable form under the high-temperature condition of 110 °C. The physical and chemical compatibility of each component of the FCPCM is good. The 24 h leakage rate is maintained below 1 %, which is only 56 % of the leakage rate of the FCPCM with OBC as the support material. In general, 8 wt% SEBS and 8 wt% OBC are the best ratio. In addition, the battery thermal management experiment shows that the FCPCM can control the battery temperature at 49.3 °C at a 2C rate, which is 10 °C lower than the condition without FCPCM. The FCPCM reduces the temperature fluctuation of the battery by at least 1 °C, whether it is charged at 1C or 2C. This shows good thermal management potential.