Heat transfer enhancement concepts for a battery thermal management system in an electrical vehicle has been evaluated and discussed in this master’s thesis project. The evaluated battery thermal system contains of cooling plates with cooling channels which are placed underneath battery modules to remove heat from the battery cells in the module. The project is split into three parts. Part 1 evaluates different concepts to improve heat transfer within the cooling plate. Part 2 considers placing fins between the cells in the module to increase heat transfer to the cooling plate, part 2 also evaluates how different cells optimizations effect the heat generation in the module and evaluates how the best plate concepts effect the module. Part 3 evaluates how different number of fins effect the module. Part 1 and part 2 are using 3D-CFD models while part 3 is a simplified model based on a thermal circuit. A number of different concepts were found that can improve heat transfer fromthe battery cells. The different heat transfer enhancement concepts has in some cases been found to effect other aspects of the vehicle, for example system pressure drop, weight, cost, range and driveability. An optimal case (from a thermal perspective) is able to lower the average temperature of the module with 16.9% and increase the conductance with 62.2%.