A design optimization study of an air-cooling battery thermal management system for electric vehicles

Air cooling is a highly cost-effective method for the battery thermal management systems due to its simple structure, high reliability and low maintenance cost. Different from other designs of only a single inlet/outlet structure in the literature, an air-cooling battery thermal management system with multiple inlets/outlets design was proposed in this paper. The effects of inlet/outlet positions and dimensions on the air-cooling battery thermal management system performance were thoroughly evaluated and compared. The optimal inlet/outlet position and dimension were identified based on the maximum battery temperature and the temperature uniformity in the air cooling field. The results showed that the symmetrical double inlets/outlets design (Design 4) delivered the top temperature uniformity with the lowest energy consumption. During 1C discharging at 2 m/s inlet airflow, the maximum temperature and temperature difference of the Design 4 were 1.01 K and 2.24 K lower than those of the basic Design 0 in addition to a pressure difference reduction of 7.85 Pa. Based on the optimal Design 4, 0.03 m outlet width could further reduce the maximum temperature and temperature difference by 0.47 K and 0.28 K than the worst 0.05 m design. Furthermore, 52 additional simulations under different operating conditions had proven that the superb cooling performance of the optimal design during mild discharging operations (0.5–1C).