Patent attributes
A positive electrode plate (7) and a negative electrode plate (8) are coiled around with a separator (9) interposed therebetween into a flat shape having a rectangular plan to obtain an intermediate product (17) of an electrode plate group, whose corners are then cut off along straight or curved lines to obtain a substantially octagonal electrode plate group (1a, 1b), so that it is accommodated in a negative electrode case (5) having a circular plan with good space efficiency. The problem of residual water in the coiled electrode plate group (1a, 1b, 1c) of a coin type battery having high load current characteristics is resolved by a vacuum dry treatment, and the problem of dust generated during the welding of leads is resolved by a method whereby dust is not scattered inside the case. Flat batteries with higher reliability are thus obtained.
