Experimental and simulative investigations on a phase change material nano-emulsion-based liquid cooling thermal management system for a lithium-ion battery pack

Thermal management systems (TMSs) are indispensable for practical applications of lithium-ion battery packs. In this study, phase change material (PCM) nano-emulsions with enhanced energy storage capacity, excellent dispersion stability, low viscosity and good thermal reliability were employed as coolants for high-performance liquid cooling thermal management systems (LCTMSs) for the first time. The maximum temperature (Tmax) and maximum temperature difference (ΔTmax) in a 5S4P battery pack were measured to evaluate the thermal management performance of these coolants. When a 10 wt% OP28E nano-emulsion was used at a flow rate of 200 mL min−1, Tmax and ΔTmax were 1.1 °C and 0.8 °C, respectively, lower than those based on water, at a discharge rate of 2C. The increase in OP28E mass fraction of the nano-emulsion led to a gradual decrease in Tmax and ΔTmax at identical discharge rates. Simulation studies were also conducted and validated by comparing with the experimental results. It was revealed that, Tmax and ΔTmax decreased with increasing flow rate of the coolants, and the thermal management performance of the 10 wt% OP28E nano-emulsion was always better than that of water. This work sheds light on improving the performance of LCTMSs by using PCM nano-emulsions.