Temperature is an important factor for an optimal battery performance. To gain knowledge about the internal temperature distribution in a battery, many thermal simulation studies are performed. Among other factors, they differ in the level of homogenization (LoH) of the geometry, which directly influences the computing time. However, the effects of different LoH, in particular of the cell layers, on the modeling and prediction quality of the temperature field are scarcely investigated. This work discusses the effect of different LoH of the cell stack on a numerical 3D thermal battery model for different thermal management strategies. A new approach of reducing the number of cell layers of the pouch cell geometry while keeping their volumetric proportions constant is proposed. It is clearly shown that the LoH has a large impact on the thermal transport paths, especially through the current collectors and tabs, and therefore on the predicted internal temperature distribution. In addition, the effect of the LoH differs for different thermal management strategies, because they affect the heat transport paths as well.