| 摘要 |
PROBLEM TO BE SOLVED: To provide a case for a secondary battery having a structure which can cleave a safety valve with a predetermined specified pressure and high accuracy even if it is used for a long period of time, and which is achieved at a low cost.SOLUTION: A safety valve 14 having a thin wall part 28 which has a thinner wall than a case body 12 for sealing a positive electrode, a negative electrode and an electrolyte in the inside thereof, and which forms a dome shape is provided to the case body 12 so as to be bulged into the inside thereof, and on only one surface in the thickness direction of the safety valve 14, a cleavage groove 32 is formed which is cleaved when the inner pressure of the case body 12 reaches a predetermined specified pressure. |
