Charge storage devices with overlapping, folded electrodes

A charge storage device includes a layered strip which is folded lengthways along fold lines (14, 15) in the directions indicated by arrows (16, 17) to form a folded layered strip (18). Strip (18) is then cut to a predetermined length (19). After the proportions of activated and conductive carbon, and the thickness of the paste, have been settled the length to which strip (18) is cut is the final determining factor for the capacitance, time constant, power density and energy density of the charge storage device. The cut length (19) is then folded crossways along fold lines (20, 21) in the directions indicated by respective arrows (22, 23) to form a twice folded structure (24).