Battery pack assembly having thermal transfer sheets and heat sink

A battery pack thermal management assembly draws heat from prismatic batteries having opposed major surfaces and arranged in a stacked configuration inside a housing. The thermal management assembly includes a plurality of thermal transfer sheets made from sheets of a compressed mass of exfoliated graphite particles. Each thermal transfer sheet is positioned to contact the major surface of at least one of the prismatic batteries. A cover plate has a top face and a bottom face and includes a plurality of apertures through which the plurality of thermal transfer sheets extend. The apertures include at least one curved sidewall and the thermal transfer sheets are bent over the curved sidewall. At least a portion of each of the thermal transfer sheets is secured between a heat sink and the top face.