Investigation of flow design and deflector plate effect in air cooled battery pack at different discharge rates

In this study, the effect of different flow designs and the use of deflector plates on the thermal performance of an air cooled battery pack was investigated using the CFD method. Model A, which has a conventional single inlet flow structures, was compared with Model B, which employs dual inlets and deflector plates. In both models, 24 cylindrical 18650 lithium-ion battery cells were used, and the inlet and outlet surface areas of the battery pack were designed to be equal. Analyses performed at 3C and 4C discharge rates showed that the dual inlet flow structure and deflector plates significantly improved the cooling efficiency of the battery pack. At a 3C discharge rate, the maximum battery temperature and maximum temperature difference obtained with Model B were 1.87 K and 1.08 K lower, respectively, compared to Model A. At a 4C discharge rate, this improvement became even more pronounced, with the maximum battery temperature reduced by 2.49 K and the maximum temperature difference decreased by 1.44 K. Examination of the temperature contours revealed that, in Model A, heat accumulation occurred particularly in the rear regions, whereas Model B achieved a more homogeneous temperature distribution.