Parameter optimization and sensitivity analysis of a Lithium-ion battery thermal management system integrated with composite phase change material

Abstract

In order to ensure the performance and to extend the life cycle of power battery module within electric vehicle, a battery thermal management system (BTMS) integrated with composite phase change materials (PCM) was proposed. The heat dissipation performance of BTMS using paraffin/expanded graphite (EG) composite PCM with different mass fraction was investigated. The results showed the optimal heat dissipation performance was observed using composite PCM with 20 wt% EG. The combined effect of liquid volume fraction and thermophysical parameters of composite PCM on heat dissipation performance of battery module was revealed. The phase transition temperature of composite PCM was found to have the largest impact on the maximum temperature and temperature uniformity of battery module, followed by latent heat and thermal conductivity of composite PCM. A 10 % decrease in the phase transition temperature led to a 7.9 % in the maximum temperature of battery module. Both the thermal conductivity and latent heat growth contributed to the reduction in the maximum temperature of battery module. Composite PCM with the thermal conductivity of 3 W m−1 K−1, phase change temperature of 38 °C, and latent heat of 220 J g−1, was found to achieve the optimal heat dissipation performance of BTMS and a high utilization rate of 97.3 % for composite PCM. The findings of this work could be beneficial for future development of highly-efficient and economical composite PCM for BTMS.