Optimizing Thermal Performance of 18 650 Lithium‐Ion Battery Packs Using Novel Composite Structures

ABSTRACT

In the battery thermal management of new energy vehicles, air cooling occupies a certain position. However, the traditional F‐type air‐cooling structure has problems such as uneven gas flow and partial heat accumulation. In response, we designed an F‐step air‐cooling structure suitable for a 24‐cell 18 650 lithium battery module. We studied the effects of air inlet position, spacing between batteries, battery arrangement angle, and inlet airspeed on cooling performance. Compared with the traditional F‐type structure, this F‐step design allows air to better flow into the gaps between batteries and also reduces areas of locally high temperature. The results show that arranging the outlets above channels 4 and 6 decreases the maximum temperature ( T _max ) by 1.139°C and the maximum temperature difference (Δ T _max ) by 0.829°C. A cell spacing of 3 mm provides the best balance between flow distribution and heat dissipation, while a cell arrangement angle of 22.5° further reduces the T _max and Δ T _max by 1.704°C and 1.543°C, respectively, compared with the in‐line arrangement. Orthogonal optimization confirms that the optimal configuration consists of outlets above channels 4 and 6, 3 mm cell spacing, and a 22.5° arrangement angle. The results of this study were achieved using computational modeling and can provide a reference for structural optimization of compact air‐cooled battery modules.