Flexible solid-solid phase change material with zero leakage via in-situ preparation for battery thermal management

<p>Composite phase change material (CPCM) has great potential in addressing the challenges associated with thermal energy storage and thermal management. However, the flexibility and latent heat capacity of CPCM exist contradiction, hindering its wide application, especially in thermal management field. Herein, a novel solid-solid polyurethane structured phase change material including as chain segments PEG4000 and hexamethylene diisocyanate coupling with expanded graphite (PHE5) has been proposed and prepared via in-situ approach. Expand graphite is uniformly distributed and the carbamate group is produced by in-situ preparation, the high latent heat and anti-leakage characteristics of PHE5 are beneficial to sustain a constant mass with zero leakage even under 150℃ heating condition. At a 3 C discharge rate, the battery module with PHE5 can reduce the maximum temperature to 59℃, which is lower than the PE-based module. Additionally, the battery system can maintain the temperature difference below 4.5℃, ensuring uniform temperature within the battery module. The flexibility and controlling temperature capabilities of PHE5 can effectively dissipate heat during charge and discharge cycles, and the mechanistic analysis of PHE5 with anti-leakage property can enhance the battery thermal safety, achieving comprehensive protection throughout normal operating and extreme conditions. Thus, this research reveals that solid-solid CPCM with polyurethane structured can improve the flexible and anti-leakage properties via in-situ preparation, which will offer an effective thermal safety solution for battery module, substantially enhancing the safety of millions of drivers and passengers.</p>