Optimization design of lithium battery management system based on Z-F composite air cooling structure

In battery thermal management system (BTMS), air cooling is a common cooling strategy to ensure the performance and safety of electric vehicles. To improve the cooling efficiency of air-cooled BTMS, this study designs and optimizes a novel Z-F composite structure BTMS by absorbing and enhancing the Z-step and F-type structures. The cooling performance of the Z-F composite structure BTMS is investigated using computational fluid dynamics (CFD) methods. The study explores the effects of factors such as the position of the outlet, the number of steps, and the alignment of the step surfaces on the cooling performance of the Z-F composite structure BTMS. The results indicate that: The outlet location has an important impact on the cooling effect. After optimizing the outlet location, the Z-F composite structure BTMS exhibits the lowest maximum temperature (T_max) and temperature difference (ΔT_max), reducing T_max and ΔT_max by 2.69 °C (6.13 %) and 2.565 °C (56.51 %) respectively compared to the Z-type BTMS, and by 1.14 °C (2.69 %) and 0.022 °C (1.10 %) respectively compared to the traditional F-type BTMS. By altering the number of steps and their length, it is found that when the number of steps is seven and the step surfaces are flush with the right side of the cooling channels, the Z-F composite structure BTMS achieves optimal cooling performance. In this configuration, T_max and ΔT_max are reduced by 2.714 °C (6.18 %) and 2.819 °C (62.11 %) respectively compared to the Z-type BTMS. Within the range of 2 to 7 m/s inlet air velocity, as the velocity increases, T_max and ΔT_max gradually decrease, but the pressure drop (ΔP) gradually increases. The pressure drop increases more slowly within the 2 to 4 m/s range, with the optimal inlet air velocity being 4 m/s. In summary, the Z-F composite structure BTMS demonstrates excellent cooling performance under various operating conditions and shows significant potential for practical applications.