Parametric Investigation on the Performance of Refrigerant Direct Cooling System for Electric Vehicle Battery

The operational performance of lithium-ion batteries is significantly influenced by ambient temperature. In high-temperature environments, if the temperature of the battery is unable to be rapidly reduced to within the normal range, it will have a significant impact on the battery’s capacity and lifespan. In comparison to alternative cooling techniques, direct evaporative cooling offers the benefits of high efficiency, optimal temperature distribution, and a straightforward system configuration. It is thus imperative to gain a thorough grasp of the design and operational parameters of the direct cooling thermal management system, and to understand its impact on performance. This paper designs a direct cooling system with R134A as refrigerant. The performance of the battery thermal management system is obtained through numerical simulation based on the thermodynamic method in two typical operational scenarios: fast charging cooling and high-speed travel cooling. The results of the study showed that the refrigerant direct evaporative cooling method exhibited superior performance in both typical operating scenarios, with a battery module temperature rise of no more than 10℃ and a maximum temperature difference of less than 5℃. Subsequently, an investigation was conducted to determine the effect of initial temperature, flow rate, evaporative temperature and dryness on system performance.