Rechargeable battery and module of the same

A rechargeable battery includes an electrode assembly that performs charging and discharging, a case in which the electrode assembly is located, a cap plate coupled to an opening of the case, and electrode terminals located in the cap plate and insulated from the cap plate by insulation members located at terminal holes of the cap plate, the electrode terminals being connected to electrodes of the electrode assembly and extending outside the cap plate and the electrode terminals including a fastening portion that receives at least a part of a bus bar to be welded.