This disclosure details exemplary battery pack designs for use in electrified vehicles. An exemplary battery pack assembly process may include supporting one or more components, such as a heat exchanger plate, of the battery pack against deflection during the assembly process. Supporting the heat exchanger plate to keep the plate relatively flat during the battery pack assembly process improves the flow distribution of a thermal interface material (TIM), thereby achieving improved TIM coverage and improved heat transfer between battery cells and the heat exchanger plate of the battery pack.