Abstract: A battery pack is provided for housing a plurality of flat cells for portable electronic device applications. The battery pack is sufficiently thin to preserve the desirable thin profile of the flat cells and yet exhibits surprising structural integrity considering the relatively thin polycarbonate material from which the housing and the connective sheets of the pack are fabricated. A first group of flat cells is coupled to one side of a central connective member or circuit board. A second group of flat cells is coupled to an opposite side of the central connective member. The cells of the first group are situated in side-by side relationship and the cells of the second group are situated in side-by-side relationship. An upper connective sheet is adhesively coupled to the upper surfaces of the first group of flat cells and the upper surfaces of the second group of flat cells.