A rechargeable battery having an insulating member is disclosed. In one aspect, the battery includes an electrode assembly including a first electrode, a second electrode, and a separator interposed between the first and second electrodes. The battery also includes a storage case housing the electrode assembly. An opening is formed in the storage case. The battery further includes a cap plate attached to the opening of the storage case, a terminal penetrating through the cap plate, and a connection plate electrically connecting the terminal to the second electrode. The battery also includes an insulating member interposed between the cap plate and the connection plate. The insulating member includes a base plate contacting a bottom surface of the cap plate and a supporting rib that protrudes from the base plate and contacts an inner surface of the storage case.