A battery module includes an enclosure that has at least one heat sink. Within the module is a stack assembly composed of a series of cell carrier assemblies connected together. The cell carrier assemblies each include a cell carrier that has a first spring that is biased against the heat sink. Each of the cell carrier assemblies also includes a battery cell and a heat conductive sheet that is thermally coupled to the battery cell. The heat conductive sheet is positioned to be pressed against the heat sink by the first spring to facilitate a good thermal connection between the sheet and the heat sink. Heat is accordingly conducted away from the battery cell, along the heat conductive sheet, to the heat sink.