PURPOSE: To provide a battery excellent in a life characteristic while improving productivity and stabilizing quality by reducing a grid break and a grid crack at the time of expand working, in a method of manufacturing an expand grid unit for the lead-acid battery.
CONSTITUTION: In an expand working cutter, as viewed from its side surface, in a point end part of the first blade 1 of a tooth form having a trapezoidal part in the point end part, an R is respectively provided in two points of a crossing part with the bottom surface and a sloped surface into contact with the bottom surface, and in the point end part of the second blade 2 thereafter, an R larger than that of the first blade 1 is provided in the topmost end part between the sloped surfaces, to perform working by using this cutter. By the method of manufacturing an expand grid unit, by reducing breaking and cracking a grid, productivity can be improved and quality can be stabilized to obtain a lead-acid battery excellent in a life characteristic.
YUKI MASAYOSHI
TSUJIMOTO MASARU
YASUDA HIROSHI
TAKAHASHI KATSUHIRO
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