Investigation on preparation, thermal, and mechanical properties of carbon fiber decorated with hexagonal boron nitride/silicone rubber composites for battery thermal management

Adding thermally conductive filler to polymer matrix is a workable way to increase its thermal conductivity. In this work, carbon fiber (CF) and hexagonal boron nitride (h-BN) were employed to obtain hybrid fillers, firstly, (mh-BN@CF) by electrostatic self-assembly method, then added mh-BN@CF to silicone rubber (SR) matrix to prepare mh-BN@CF/SR composites. There was a good interface compatibility between mh-BN@CF and SR matrix. Besides, the composites can achieve best thermal conductivity when h-BN and CF are at the optimal fill ratio. When the mass ratio of h-BN:CF is7:3 and the filling content is 54 phr, the thermal conductivity of mh-BN@CF/SR can reach 1.3 W/(m K), and it is 23.7% and 400.4% larger than the mixed-filled h-BN/CF/SR composites and SR matrix, respectively. Simultaneously, the mh-BN@CF/SR composites also exhibited good electrical insulation, mechanical properties, and thermal stability. Finally, the prepared composites are used in a liquid-cooled battery thermal management system (BTMS). The effect of the composites on the performance of the BTMS is discussed by numerical method. The results show that the improved thermal conductivity of the composites can highly reduce the temperature of the battery cells. The prepared composites can highly enhance the performance of BTMS.