In a closure assembly for sealed rechargeable batteries, upon a metallic foil is placed a spacer having an aperture that is larger than an upwardly protruding portion of the foil but smaller than the outside diameter of the foil, and upon a metallic safety vent is placed either a spacer and a metallic cap, or a metallic cap only, the spacer and/or metallic cap having an aperture that is larger than a downwardly protruding portion of the safety vent but smaller than the outside diameter of the safety vent, so as to control and suppress deformation of the metallic foil and safety vent in the event of abnormal battery pressure increasing due to overcharging or the like and to ensure that rupture occurs at a predetermined pressure level, whereby a sealed rechargeable battery suitable for high-output applications and having high safety features is provided.