High Antileakage and Thermal Conductivity Composite Phase-Change Material with Anisotropy Expanded Graphite for Battery Thermal Management

Abstract

Battery thermal management systems (BTMSs) with composite phase-change materials (CPCMs) have attracted much attention owing to their improved temperature consistence in battery packs, but they still have obvious challenges such as easy leakage and low thermal conductivity. Herein, paraffin (PA)/styrene–butadiene–styrene (SBS)/thermoplastic polyurethane (TPU)/expanded graphite (EG) (PSTE) has been successfully prepared and utilized in battery modules. PSTE exhibits high antileakage under 70 °C high-temperature condition, which can maintain the quality maintenance rate to more than 99.9% compared with other samples. It is attributed that TPU as the interpenetrating layer can mingle with SBS uniformly, which will play a synergistic effect to restrict the leakage of CPCM. Besides, the thermal conductivity values of PSTE with various mass fractions of EG between the axial and radial directions after compression are compared. It reveals that the thermal conductivity of PSTE with 4 wt % EG is much higher than that of pure PA in the radial direction after compression. Meanwhile, the mechanism of EG with anisotropy is explained in detail. Further, the temperature consistence of the battery module with PSTE4 is markedly higher than other two modules, and the maximum temperature and temperature difference can be controlled below 44.7 and 3.6 °C, respectively, which indicates that PSTE4 can promptly dissipate the heat generated with batteries. Therefore, the designed CPCM with a highly efficient antileakage and thermally conductive composite material will provide versatile thermal management systems in practical applications.