Numerical simulation of indirect contact phase-change cooling system with R1234yf/R152a mixed refrigerant for battery thermal management

Refrigerant indirect contact phase-change cooling system flows refrigerant into a cold plate and utilizes the phase-change to exchange heat with the battery. However, R134a, commonly used, is being gradually restricted due to its environmental impact. A new kind of near azeotrope mixed refrigerant R1234yf/R152a (mass ratio 60.5:39.5) is proposed under environmental protection and safety. Based on the fluid-structure interaction model, the evaluation of different indirect contact phase-change cooling systems for battery thermal management (BTM) using R1234yf/R152a is investigated. After obtaining battery (150 Ah, 3.2 V LiFePO4) parameters, heat generation power, and main test conditions through experiments, the thermal properties are numerically studied by computational fluid dynamics (CFD). At 1 C discharge rate, the temperature gradient (TG) of single battery and the maximum temperature difference (TD) among batteries are analyzed for two cases: The maximum TD among batteries of Case_b is 6.5°C lower than that of Case_a. In addition, the effect of the mixed refrigerant and traditional liquid cooling on the battery temperature is studied at different evaporation temperatures (ETs) (20°C, 25°C) and different mass flow rates (MFRs) (0.02, 0.10, and 0.18 kg/s). The results show that both the increase of inlet MFR and the reduction of inlet ET may significantly improve the battery module cooling rate. Compared with 0.02 kg/s, as the MFR increases, the temperature drop slopes to 9.56 and 11.2 at 20°C. The battery module temperature uniformity is improved with the increase of ET. Overall, the mixed refrigerant has advantages in temperature uniformity and consistency. The new mixed refrigerant plays a positive role in controlling battery temperature.