Terminal for sealed battery and manufacturing method therefor

A method for forming a terminal unit for a sealed battery, the battery including an outer can having mouth portion, an electrode assembly having a collector and housed inside the outer can, a sealing plate fixed in a sealed state to the mouth portion of the outer can and having an opening bored therethrough, a terminal installed inside the opening of the sealing plate and electrically connected to the collector, the method comprising:

• preparing as the terminal an outer terminal, of a solid flat rivet shape, that has a brim portion and a columnar axle portion between which a curved surface is formed, an inner terminal, of a hollow flat rivet shape, that has a brim portion and a hollow axle portion that is longer than the columnar axle portion of the outer terminal, a first insulating member having an opening, and a second insulating member having an opening;
• inserting the hollow axle portion of the inner terminal, from inside the outer can, through the opening of the first insulating member, the opening bored in the sealing plate, and the opening of the second insulating member, in the order given, in such a state as to be insulated from the sealing plate;
• inserting the columnar axle portion of the outer terminal, from outside the outer can, into the hollow axle portion of the inner terminal;
• applying pressing force between the brim portion of the outer terminal and the brim portion of the inner terminal and crimping the columnar axle portion of the outer terminal into the hollow axle portion of the inner terminal, and curling-processing a tip of the hollow axle portion of the inner terminal to match the curved surface between the brim portion and the columnar axle portion of the outer terminal;
• and
• further applying pressing force between the brim portion of the outer terminal and the brim portion of the inner terminal and forming a radially bulge-deformed portion in the columnar axle portion of the outer terminal.