This study is to investigate the cooling performance of the battery in the electric vehicle depending on the attachment of the cooling plates and materials to the battery cells. Research focused on the numerical comparison of forced convective heat transfer coefficients with case 1(cell-Al, cooling plate-None), case 2(cell-Al, cooling plate-Al), case 3(cell-Al, cooling plate-C), and case 4(cell-C, cooling plate-Al). Normalized local Nusselt number of the cooling area at the normalized width position indicated that the heat transfer coefficient of the case 1 was averaging at 7, 14.5, 11.9% lower than that of case 2, case 3, and case 4. Based on case 3, the cooling performance with six different types of mass flow rates (0.05, 0.075, 0.0875, 0.1, 0.125, 0.15 kg/s) were compared. Normalized local Nusselt number at the normalized width position indicated that the heat transfer coefficient of 0.0875 kg/s was averaging at 35.8, 11.9% higher than that of 0.05, 0.075 kg/s and 12.3, 36.4, 60% lower than that of 0.1, 0.125, 0.15 kg/s. Ultimately, the best optimization design for air-cooling performance was case 3 with mass flow rate of 0.125 kg/s.

This study is to investigate the cooling performance of the secondary battery in electric vehicles according to three different gaps between battery cells. To accomplish the convective cooling performance of the battery surface with three different gaps, selected local positions (X, Y, Z) for various temperature distributions were marked on the gap surface contacting the cell surface. The cooling performance of the gap of 0.5 mm was compared with the gaps of 5 mm, and 1 mm. Normalized local Nusselt number of the cooling area at the normalized width position indicated that the gap of 0.5 mm was on average 26.99% lower than that of 5 mm and 0.49% lower than that of 1 mm. At the normalized height, the gap of 0.5 mm was on average 12.12% higher than that of 1 mm. Because of the vortex at the outlet area, cooling performance at the gap of 0.5 mm was on average 13.19% higher than that of 5 mm and 0.79% higher than that of 1 mm at normalized thickness. Ultimately, the best cooling performance existed at the gap of 5 mm, but the gap of 0.5 mm was best for improving space efficiency, energy storage capacity, and vehicle-driving durability.