JP2877492B

PURPOSE:To enhance the airtightness of a sealed battery by forming a gas vent hole through a battery container, and welding a metal ring to the container via a metal thin film which is ruptured by a rise in the internal pressure of the container, and isolating the gas vent hole from the inside. CONSTITUTION:To weld a battery container 1 to a metal thin plate 3 made of a material which is largely different in thickness from the material of which the container 1 is made, the thin plate 3 is sandwiched between the container 1 and a metallic ring 4 with the same thickness as the container 1 and then the thin plate 3 is located at the center of the overall thickness of the welding portion, so that the failure of welding can be avoided. Thereby the phenomenon of liquid leakage due to pin holes and blow holes, etc., can be prevented during installation of an implosion-proofing device, so enhancing the airtightness of the sealed battery.