| 摘要 |
PROBLEM TO BE SOLVED: To provide an explosion protecting safety valve for a sealed battery, equipped with a structure providing a fixed release pressure as a safety valve while securing a remaining thickness not causing a failure of airtightness, in the case of a coined safety valve. SOLUTION: In a coined safety valve, an easily deformable groove 4 forming an easily movable part as provision for an increased internal pressure is formed around an outline forming groove 2 formed by a marking punch 3. Lateral stresses are applied to the outline forming groove 2 formed by the marking punch 3 by applying lateral stresses on a bottom part of the outline forming groove 2 formed by the marking punch 3. This enables a fixed working pressure as a safety valve to be obtained while securing a remaining thickness not causing a failure of airtightness.
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