Wide-temperature flexible phase change materials with enhanced electrical insulation for battery thermal management

Abstract

Thermally induced flexible composite phase change materials (CPCMs) have been widely used in the field of battery thermal management (BTM) recently, but their narrow-temperature flexibility and low resistivity are not conducive to thermally safe and reliable applications. In this study, using paraffin (PA) as PCM, styrene-butadiene-styrene (SBS) as flexible support material, aluminum nitride (ALN) mainly as electrical insulation, and expanded graphite (EG) mainly as thermal conductivity enhancement, a novel CPCM with enhanced electrical insulation property and wide flexible temperature (25 °C to 60 °C) was successfully prepared. The addition of ALN not only improves the volume resistivity of CPCM but also contributes to the cyclic stability of the material. The melting enthalpy decreases by only 3.57% after 500 thermal cycles ensuring the stability of practical application, that only 100–200 cycles of previous CPCMs reported. The BTM experiments indicated that the maximum temperature and maximum temperature difference can be controlled within 47 °C and 5 °C respectively, which is 15.94 °C and 4.93 °C lower than that of the naturally cooled battery. Thermal conductivity and enthalpy play a decisive role in ensuring the temperature uniformity and maximum temperature respectively, which provides guidance for the preparation goal of CPCMs.