A battery module includes an electrode assembly in a case, at least one current collector in the case, the current collector being electrically connected to the electrode assembly, a cap plate covering the case, the cap plate including a safety vent and at least one terminal inserter penetrating the cap plate, at least one terminal part including a terminal plate outside the case and a connector connecting the at least one current collector to the terminal plate through the at least one terminal inserter, at least one fixing member fixing the terminal part into the cap plate, and a groove pattern in an area of the cap plate adjacent to the safety vent.