BATTERY SAFETY VALVE MANUFACTURING METHOD, BATTERY SAFETY VALVE MANUFACTURING DEVICE, BATTERY SAFETY VALVE, AND BATTERY CASE LID MANUFACTURING METHOD

In a method for manufacturing a battery safety valve according to the present invention, a stainless steel metal sheet is used, and an thin annular portion 3 constituting an edge portion of a safety valve 2 is formed in a lid 1 by simultaneously pressing annular projecting portions 23 provided respectively on a punch 21 and a die 22 so as to oppose each other, against respective surfaces of the lid 1.