The objective of this study was to numerically accomplish the cooling performance of an electric vehicle driving motor depending on cooling channel design. Cooling performances of novel cooling channels were compared based on the temperature of coils and cooling channels as well as convection heat transfer coefficient in electric vehicle driving motors. Local axial positions of cooling channels at three different cases were marked for numerical comparison of heat transfer coefficients. Owing to forced convection by the boundary and flow conditions, the heat transfer coefficient of Case 3 at the location where pin-fins were attached in the cooling channel was improved 85.02 and 65.77% compared to Cases 1 and 2, respectively. In Case 3 with pin-fins having 50% of cooling channel length, the maximum temperature of the coil was 4.25% lower than that of Case 2 with pin-fins having 30% of the cooling channel length and 6.98% lower than that of Case 1 without pin-fins in the cooling channel. As a result, pin-fins finally diminished the maximum temperature of coils in Cases 2 and 3. Ultimately, Case 3 showed the best cooling performance for improving vehicle driving durability and developing next-generation electric vehicle cooling system technologies.

This research is to investigate the augmentation of cooling performance of water-cooling in the electric vehicle secondary battery. The research focused on the numerical study of heat transfer coefficients for cooling performance augmentation. To improve the water-cooling performance with three different inlet sections of water-cooling and five different mass flow rates, air-cooling, and water-cooling were compared. To compare the water-cooling performance, selected local positions for various temperature distributions were marked on the battery cell surface. The normalized local Nusselt number of the cooling area at the normalized height position indicated that the heat transfer coefficient of the combined section was averaging at 77.95 and 58.33% higher than that of the circle and square, respectively. The heat transfer coefficient with the normalized width by water-cooling at combined section was averaging at 5.15 times higher than that of the air-cooling. At the normalized height, the cooling performance at the water flow rates of 10 Lpm was averaging at 68-74% higher than that of 5 Lpm and 35-39% lower than that of 25 Lpm. Ultimately, the best cooling performance existed with the combined section, and the water flow rate of 10 Lpm was most appropriate, given the temperature difference and power consumption.