Analysis of coolant inlet/outlet layout and non-uniform cell spacing on thermal management of pouch battery packs

초록

Managing temperature non-uniformity in air-cooled lithium-ion battery packs remains a major challenge because airflow distribution is highly sensitive to inlet-outlet placement and inter-cell spacing, directly affecting safety, degradation, and performance stability. Although many airflow layouts have been proposed, most studies examined only a few configurations and under differing geometries or operating conditions, limiting meaningful comparison. This numerical study presents the first unified evaluation of thirteen inlet-outlet layouts, inspired by letter-shaped geometries (F, H, I, L, N, T, U, Z), for a ten-cell pouch module. All configurations are assessed under identical geometric parameters, heat-generation rates, and mass-flux conditions to isolate layout-driven thermal behavior. A second objective is to investigate four non-uniform spacing patterns and examine how spacing interacts with the flow structure of each layout. Results show that the I-type layout provides the most uniform temperature distribution, reducing the maximum temperature difference by 13.6 K compared with the conventional Z-type at a mass flux of 20 kg/m2 & sdot;s. Increasing coolant flow further enhances the performance of the I, T1, H2, and U layouts, with H2 delivering strong upstream cooling at modest pressure drop. Spacing analysis reveals clear layout-dependent trends: a decreasing-spacing pattern reduces the maximum temperature difference in the F2, L2, and N layouts by 23.99%, 6.87%, and 15.83%, respectively. The greatest improvement occurs in the T2 layout under the DEC-INC pattern, lowering average temperature by 22.32 K and reducing maximum temperature difference by 48.78%. These findings establish a unified benchmark for airflow-layout comparison and identify spacing strategies that improve air-cooled battery thermal management.

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