A pourable, thermally conductive and electronic insulated phase change material for thermal management of lithium-ion battery

Phase change materials have been widely studied for the applications in the thermal management of lithium-ion batteries. However, the complicated and high-cost pre-pressing and molding assembly processes are usually required, which makes it difficult to be industrialized. Hence, it is necessary to develop an easy-to-pour, highly thermally conductive, and electrically insulated phase change material to meet the requirements of lithium-ion battery. In this study, a pourable phase change material with high thermal conductivity and electrical insulation (PCPM) was prepared based on the electrostatic self-assembly of expanded graphite (EG) and boron nitride (BN). It was found that the volume resistivity of the PCPM could be effectively improved by coating functionalized EG (f-EG) with functionalized BN (f-BN), and when f-EG: f-BN was 1:3, the volume resistivity was increased by 6.18 times compared to that of the PCPM prepared without coating f-BN. Meanwhile, PCPM possessed a lower viscosity of 398.11 cP compared to the PCPM without f-BN, and lower viscosity results in the desired fluidity of the product as a potting material. Compared to pure polymer matrix (PUR), the thermal conductivity of the PCPM with 35 % m-EG@PA (f-EG: f-BN = 1:2) was increased by 200.4 % to 0.6011 W/(m· K). The results of the heating experiment of the simulated battery indicated that the thermal management efficiency of PCPM was significantly higher than that of PUR. At the end of the heating period, the surface temperature of the battery module with PCPM was 5.12 ℃ lower than that of the module with PUR at the end of heating, and 2.41℃ lower than that of the module with commercial high thermal conductive potting compound.