Abstract: A method includes the steps of: with the use of a winding core having a first member wherein its cross sectional-area in the direction orthogonal to the revolving axis and the peripheral length of the cross section are larger than those of a second member, passing a strip-shaped separator between the first member and the second member, placing one strip-shaped electrode plate near the second member such that the plate is not in contact with the winding core, and winding for one revolution the one electrode plate and the strip-shaped separator toward the first member; placing another strip-shaped electrode plate between the inner and outer portions of the separator that have been revolved along with the one electrode, winding both electrodes along with the separator toward the first member by revolving the winding core; removing the winding core and pressure-molding the resulting wound article into a flat wound electrode assembly.

Abstract: By an easy means the volume energy density of a flat wound electrode assembly in a cell using a flat wound electrode assembly is improved with reliability.