An electric conductive wide-temperature flexible phase change material for all-climate battery thermal management

Abstract

Battery thermal management with phase change materials (PCM) has been limited by leakage, low thermal conductivity and rigidity, and the inability to preheat at low temperatures. To solve these problems, a wide-temperature flexible composite PCM (FCPCM) was prepared with a high-temperature open refining method. Styrene ethylene butylene styrene (SEBS) and expanded graphite (EG) absorb paraffin (PA) onto a three-dimensional network. The FCPCM possesses good flexibility before and after phase transition. It can be bent and stretched arbitrarily at room temperature, and the shape memory function enable it can be restored to its original state after heating. The latent heat of the FCPCM-15 is 159.9 J/g and its thermal conductivity was 7.45 times higher than that of pure paraffin. The FCPCM also possesses a good volume conductivity of 92–2952 S/m and allows for uniform electrical heating. The excellent thermal and electrical performance of the FCPCM allows it to cool batteries at high temperatures and preheat batteries at low temperatures. After ten charge/discharge cycles at 30 °C, the battery pack’s temperature based on FCPCM cooling is still reduced by 3.9 °C. At a low temperature of −20 °C, the preheating rate of the battery pack can reach 12.9 °C/min, and the discharge voltage and capacity of the battery pack were increased by 15 % and 20.8 % after preheating. The FCPCM suggests a promising and practical approach way for the all-climate thermal management of batteries.