Optimization and working performance analysis of liquid cooling plates in refrigerant direct cooling power battery systems

Refrigerant direct cooling is currently being considered as an efficient thermal management technology in power battery systems. In this paper, four types of liquid cooling plates for power battery modules are designed and the computational model is constructed. With the model being validated, it is applied to analyze the effects of the cooling plate structure and cooling channel on the cooling and heat dissipation performances. The results reveal that for the conventional cooling method, i.e., when the cooling plate is placed on the bottom of the battery pack, a significant temperature gradient in the vertical direction is observed. On the contrary, adopting a serpentine cooling plate structure in the main wall or parallel cooling channels in the narrow side wall could significantly reduce the temperature difference of the battery pack, which can keep the temperature difference within 5 degrees C even under extreme conditions. Further, a detailed analysis of the heat dissipation performance based on the optimal cooling plate structure is performed to determine the safe operating range of the battery pack. It is shown that as the humidity is less than 0.73 and the evaporation temperature is below 15.43 degrees C, the battery pack can operate safely. However, beyond this condition range the heat dissipation characteristics of the battery pack cannot satisfy the operating requirements. This work sheds light upon the potential of refrigerant direct cooling strategy in power battery thermal management systems by properly arranging the cooling plate.