A rechargeable battery configured to prevent or substantially prevent explosion resulting from overheating. In one embodiment, a rechargeable battery includes: a first metallic plate; a second metallic plate coupled to the first metallic plate to together include five sides of a hexahedron and define a cavity and an opening to the cavity being a sixth side of the hexahedron, at least one of the first metallic plate or the second metallic plate including a base and walls extending from at least two opposing peripheral sides of the base; a generation member in the cavity and including at least one connection member at a side of the generation member proximate the opening; and a cap assembly including an insulator and at least one electrode lead coupled to the at least one connection member, the cap assembly closing the opening.