Abstract: A battery pack is provided for housing a plurality of fiat cells for portable electronic device applications. The battery pack is sufficiently thin to preserve the desirable thin profile of the fiat cells and yet exhibits surprising structural integrity considering the relatively thin polycarbonate material from which the housing of the pack is fabricated. A plurality of thin cells is laterally arranged side by side in spaced-apart relationship to form a cell subassembly. An adhesive is applied to a polycarbonate sheet. The sheet is then cut to a predetermined form and embossed to form creases along predetermined fold lines. The prepared sheet is then folded at the fold lines and positioned to substantially surround the cell subassembly and form a box-like structure around such subassembly. Adhesive on an upper sheet section adheres to the top planar surfaces of the fiat cells while adhesive on a lower sheet section adheres to the bottom planar surfaces of the flat cells.