| 摘要 |
PROBLEM TO BE SOLVED: To safely rupture a sealed battery without damaging the periphery even when excessive external force is applied by setting a value of the ratio of the inside cross-sectional area of a battery vessel to the opening area of a cleavable safety value to a specific value. SOLUTION: The ratio of the inside cross-sectional area of a battery vessel to the opening area of a cleavable safety valve is set to 30 to 300. The cleavable safety valve 3 composed of Ni foil is installed on a cover plate 1 composed of SUS 304, and the cleavable safety valve 3 is installed on the inside surface side of the cover plate 1 by being welded by a laser by applying a valve presser ring 4. The cover plate 1 having the same dimension and the same construction is prepared except when the opening part 2 is not arranged in the cover plate 1 so that the cover plate 1 having the opening part 2 is installed in the opening part of a cylindrical battery vessel. At this time, a terminal is electrically continued through a current collecting tab of one polarity from a plate group, the terminal is derived outside a battery from a terminal installing hole existing in the center of the cover plate 1, and the terminal is fixed to the cover plate 1 by a screw and packing so as not to generate clearance. |
