Experimental assessment on the thermal control performance of composite phase change material for fast charging power module

Abstract

The broader introduction of electric vehicles requires an improvement of battery technology or a more extensive charging infrastructure setup. In order to solve the thermal control problem of high power fast charging piles, the novel thermal control method combining liquid cooling and a small amount of composite phase change materials covered on the upper surface of the charging power module is proposed. An experimental study on the temperature rise and temperature uniformity of the power module surface is compared with single liquid cooling. Results show that adding a small amount of composite phase change material can keep its maximum temperature in the allowable operating range and make temperature uniform around the power module surface compared to the reference solution. The addition of composite phase change materials with a filling thickness of 3 mm gives an overall temperature decrease of 15.531 °C. Compared to the single liquid cooling, increasing the liquid flow rate or decreasing the liquid initial temperature will weaken the further thermal control improvement on the power module. The addition of composite phase change material can effectively keep its maximum temperature in the operating range for the fast charging pile under the larger heat generation power. The phase transition temperature of 52 °C is recommended because of the minimal temperature peak of the power module is obtained. Increasing the composite phase change material thermal conductivity from 6.05 W·m−1·K−1 to 8.99 W·m−1·K−1 will reduce the maximum temperature of the power module by 5.88 %. However, the temperature rise process of the power module suggests that the heat dissipation is mainly determined by the liquid cooling, and very low heat dissipation through the conduction and radiation of composite phase change materials. A slower temperature rise in the latent heat absorption process is observed as increasing the composite phase change material filling thickness, but no significant reduction in the temperature rise is found in the operating time of 15 min. The benefit of using the composite phase change material is reduced by 7.71 % as the cycle times are given as 100. Developing the more effective and stable composite phase change material or replacing the composite phase change materials at regular intervals is needed to ensure its effectiveness for the thermal control performance of the fast charging power module. The present research works show very promising results on the limited researches on the cooling scheme of power devices in higher current fast charging piles.