High thermal conductivity composite phase change material with nano-Ag particles modified diatomite and expanded graphite for improving battery thermal management efficiency

Composite phase change materials (CPCMs) with significant amounts of latent heat can absorb and release at a constant transition temperature have attracted much attention in energy storage and electrical vehicles fields. Nevertheless, it is still a great challenge to utilize in battery thermal management system owing to low thermal conductivity and liquid leakage . Although many efforts have endeavored to improve transferring heat capacity, the thermal conductivity of CPCM is still need to explored. Herein, a novel high thermal conductivity and anti-leakage CPCM including polyethylene glycol, nano-Ag particles modified diatomite and expanded graphite (PDAE) has been designed and prepared. And the nano-Ag particles have evenly attached to the surface of diatomite through in-situ chemical reduction reaction and self-assembly technology. The experimental results indicate that PDAE exhibits excellent thermal conductivity with 1.91 W∙m −1 ∙K −1 owing to three-dimensional heat transferring network constructed by nano-Ag particles and expanded graphite. Moreover, it is no shape variation and leakage of PDAE under continuously heated at 60 °C for 2 h. In addition, the temperature performance of battery modules with the different CPCMs have been compared in detail, the results demonstrates that battery module with PDAE can be maintained below 53 °C and the temperature difference is effectively controlled within 5 °C even at 3C discharging rate after 10 cycles. With these prominent performances, this designed CPCM with high thermal conductivity will offer a promising insight into the passive thermal management system in practical application.