Cell having flat wound electrode assembly and method of producing such cell

A method of producing a cell comprising a flat wound electrode assembly, the method comprising the steps of:

• with the use of a winding core comprising a first member wherein its cross sectional-area in the direction orthogonal to a revolving axis and a peripheral length of the cross section are larger than those of a second member and the second member wherein its cross sectional-area in the direction orthogonal to the revolving axis and the peripheral length of the cross section are smaller than those of the first member, and after 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 the other strip-shaped electrode plate between inner and outer portions of the separator that have been wound along with the one electrode, and winding the both electrode plates along with the separator toward the first member by revolving the winding core;
• and
• removing the winding core and pressure-molding the resulting wound article into the flat wound electrode assembly.