Effect of cooling plate channel configuration on the cooling performance of lithium-ion battery pack

Abstract It is essential to replace fossil fuel vehicles with electric vehicles in the fight against global warming. Fast-charging and large-capacity battery packs will be of great importance for accelerating this process and the widespread use of electric vehicles in the future. However, good thermal management is needed to use these battery packs effectively. In this study, the thermal management of nickel, manganese and cobalt lithium-ion battery packs is investigated using two cooling methods: the formed cooling plate and the piped cooling plate. A 3D numerical model was created to determine the optimum cooling plate design, and computational fluid dynamic analysis was performed. The numerical model was validated by cooling tests on a battery pack comprising 16 modules and 192 cells. Changing the channel geometry reduced the maximum temperature difference in the battery pack by approximately half. The maximum temperature difference in the battery pack in the reference piped cooling plate was measured at 8.0 °C in the tests. While the maximum temperature difference is reduced to 3.3 °C by changing the channel geometry with the piped cooling plate, it is reduced to 3.9 °C with the formed cooling plate. This corresponds to a cooling performance improvement of 14.7% for the optimized formed cooling plate (FCP-4) and 9.9% for the optimized piped cooling plate (PCP-4) with respect to the reference design. Thus, a relatively homogeneous temperature distribution was achieved on the battery pack. In addition, by reducing the cell's maximum temperature from 30.0 to 25.6 °C using the formed cooling plate, the cell internal resistance is reduced by 18.3%, and the predicted capacity loss over an 8-year equivalent operation is reduced by about 5 percentage points. For an 8-year equivalent operation, the capacity loss of the cells is reduced from 15.8% in the reference pack to 12.3% with the optimized piped cooling plate (PCP-4) and 10.7% with the optimized formed cooling plate (FCP-4). Overall, the study provides a pack-level quantitative demonstration that optimizing the cooling plate channel geometry in an automotive-type NMC battery pack can simultaneously improve thermal uniformity and reduce long-term degradation, thereby increasing the lifetime and performance of the battery pack.