Optimization design of the forced air-cooled battery thermal management system with a stepped divergence plenum

In order to improve heat dissipation performance of battery pack with air-cooled structure, a novel stepped divergence plenum in Z-type air-cooled structure is proposed in a prismatic battery pack. Then the accuracy and effectiveness of computational fluid dynamics (CFD) model are verified by comparison with experimental results. Subsequently, the effects of the total height of all steps and the height of every step on the maximum temperature, temperature difference and temperature standard deviation of battery pack with air-cooled structure are explored, respectively. Finally, the stepped divergence plenum at different inlet airflow velocity is further optimized to achieve better cooling performance. Numerical results indicate that 1) For the larger total height of the steps, the stepped divergence plenum is suitable for Z-type air-cooled structure, and the stepped divergence plenum is better than the slanted one in the aspect of cooling efficiency while the latter is superior to the former for the smaller total height of the steps 2) Compared with the slanted divergence plenum, a stepped divergence plenum improves the heat dissipation performance of the battery for Z-type air-cooled structure. 3) The height of every step and inlet airflow velocity plays an important role in the cooling performance of the battery. The optimization results are h = 0.125 (i.e, Hopt = [1.39, 2.51, 2.51, 2.02, 2.02, 1.89, 1.76, 1.39, 1.51]) and 3 m/s, and the corresponding maximum temperature, temperature difference and temperature standard deviation of the battery pack are respectively reduced about 34.65 %, 77.51 % and 99.04 % in comparison with those for Z-type model. The optimization scheme proposed in this work provides a design guideline to improve the cooling performance of the air-cooled structure.