Experimental investigation on system performances and transient response of a pumped two-phase battery cooling system using R1233zd

Abstract

This study presents an experimental investigation on the pumped two-phase cooling system designed for battery thermal management. The experimental system was established with R1233zd as the refrigerant, and a dummy battery was used to simulate the heat generation during battery operation. The thermodynamic cycle, wall temperature distribution of the cold plate and overall heat transfer coefficient were analyzed under steady state, while the transient response of the system with pump control was also studied. Results showed that the evaporating pressure of the system was not sensitive to the refrigerant mass flux, while it could be raised under higher heating loads. Both the refrigerant mass flux and vapor quality at the cold plate outlet showed little influence on the wall temperature distribution of the cold plate, however their effects on the overall heat transfer coefficient were different. An optimum value of vapor quality at cold plate outlet could be found for the pumped two-phase cooling system to achieve a maximum heat transfer coefficient. Based on this feature, a pump control program was designed and embedded into the system, and transient experiment showed that the control program could effectively handle the sharp increase of heating load. The application of the control program could lead to a near 10 K decrease in wall temperatures of the cold plate by maintaining the outlet vapor quality of the cold plate at 0.25 when the heating load was instantly raised from 100 W to 600 W, meanwhile the growth of wall temperature was also slower. The results of this study can serve as a guideline for the application of pumped two-phase cooling system on battery thermal management.