BATTERY

A battery includes a case, an electrode group, a sealing unit including a conductive cap, a terminal plate joined to an opening edge of the case, and an insulating plate that electrically insulates the conductive cap from the terminal plate. The case and the terminal plate are electrically connected to a first electrode, while the conductive cap is electrically connected to a second electrode. The terminal plate has a first connection region to which a first external terminal is to be connected. The conductive cap has a second connection region to which a second external terminal is to be connected. The terminal plate has a planned breaking part between the first connection region and a joint part thereof joined to the opening edge of the case. The planned breaking part breaks when the internal pressure of the case exceeds a predetermined value, separating the terminal plate in the axial direction of the case into a broken piece on the outer peripheral side and a broken piece on the inner peripheral side.