PURPOSE: To prevent the short-circuit with the ear portion or the strap due to the deformation of an anode plate, by inserting the plate into a micro-porous separator then thermally fusing the both side faces and the upper end side with the central portion.

CONSTITUTION: An anode plate 1 made of a cast grid body or an expand grid body is inserted into a micro-porous separator 2 made of a synthetic resin or synthetic fiber having the flexibility then the rib 15 is positioned at the anode plate side 1 and bent at the intermediate portion, thereafter both sides 18 are thermally fused while simultaneously the upper end side and the central portion are thermally fused to form a fixed section 19. Consequently the short-circuit with the ear section of the cathode plates group or the strap due to the expansion, bending of the upper portion of the anode plate 1 due to the repetation of the charge/discharge can be prevented reliably resulting in the lengthening of the service life of the battery.