An electrode group 1 is stored in a rectangular tubular metal container 2. The electrode group 1 has a structure formed by spirally winding a positive electrode 5 and a negative electrode 3 with a separator 4 interposing therebetween so as to form a flat shape. An aqueous electrolyte (not shown) is held by the electrode group 1. As shown in FIG. 3, a strip-shaped positive electrode side lead 22 is electrically connected to each of a plurality of portions at an end of the positive electrode 5 located on an end face of the electrode group 1. In addition, a strip-shaped negative electrode side lead 23 is electrically connected to each of a plurality of portions at an end of the negative electrode 3 located on the end face. The plurality of positive electrode side leads 22 are electrically connected to a positive electrode tab 16 in a bundled state. A positive electrode terminal is formed from the positive electrode side leads 22 and the positive electrode tab 16. In addition, the negative electrode side leads 23 are electrically connected to a negative electrode tab 17 in a bundled state. A negative electrode terminal is formed from the negative electrode side leads 23 and the negative electrode tab 17. A sealing plate 10 made of a metal is fixed to the opening portion of the metal container 2 by welding or the like. The positive electrode tab 16 and the negative electrode tab 17 are extracted to the outside from outlet holes provided in the sealing plate 10, respectively. The inner surface of each outlet hole of the sealing plate 10 is coated with an insulating member to avoid a short circuit caused by contact between the positive electrode tab 16 and the negative electrode tab 17.
