Proper cell selection is determinant to optimize systems and reduce risks for new and high demanding areas such as electromobility. Thermal performance must be an indispensable selection criterion to avoid thermal issues in these fields, so cells should be correctly characterised and modelled. In this paper, an improved cell selection methodology that focuses on the thermal performance criterion especially for fast charging applications is proposed. After a first selection, two cell candidates were characterised and their heat generation was modelled and compared. With the selected cell, heat generation rate was determined and a 3C fast charge was performed to evidence the predicted thermal performance. The improved methodology identified a cell with an advantageous entropic heat coefficient (EHC) for fast charging, decreasing the heat energy generation by 54% concerning the other candidate cell, which results in optimisation of the thermal management system (TMS). This emphasizes the importance of proper cell selection based on thorough thermal characterization.