A rechargeable battery module, comprising: a plurality of unit cells, each of the unit cells including a rechargeable battery, comprising: 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 (21, 22, 221, 222), each being located in the cap plate and insulated from the cap plate by an insulation member (31, 32) located at a respective terminal hole (H1, H2) of the cap plate, the electrode terminals being connected to respective electrodes of the electrode assembly and extending outside the cap plate wherein each electrode terminal is in a form of a band having a width and a thickness, is welded to an uncoated (11b, 12b) of an electrode of the respective electrode assembly, said uncoated portion consisting of a current collector which is not coated with an active material; and each electrode terminal has a fastening portion projecting outside the case, and the rechargeable battery module further comprises a bus bar (200, 300) connecting two respective said electrode terminals of the unit cells; wherein the fastening portion of each of the electrode terminals receives at least a part of the bus bar; and wherein the rechargeable battery module is in that each said fastening portion includes a first concave recess (41, 51, 241, 251) that is open toward one side of the electrode terminal in a width direction and in that the bus bar (200, 300) includes second concave recesses (62, 72, 262, 272) formed to be matched to the first concave recesses and coupled to the first concave recesses. a plurality of unit cells, each of the unit cells including a rechargeable battery, comprising: 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 (21, 22, 221, 222), each being located in the cap plate and insulated from the cap plate by an insulation member (31, 32) located at a respective terminal hole (H1, H2) of the cap plate, the electrode terminals being connected to respective electrodes of the electrode assembly and extending outside the cap plate wherein each electrode terminal is in a form of a band having a width and a thickness, is welded to an uncoated (11b, 12b) of an electrode of the respective electrode assembly, said uncoated portion consisting of a current collector which is not coated with an active material; and each electrode terminal has a fastening portion projecting outside the case, and the rechargeable battery module further comprises a bus bar (200, 300) connecting two respective said electrode terminals of the unit cells; wherein the fastening portion of each of the electrode terminals receives at least a part of the bus bar; and wherein the rechargeable battery module is in that each said fastening portion includes a first concave recess (41, 51, 241, 251) that is open toward one side of the electrode terminal in a width direction and in that the bus bar (200, 300) includes second concave recesses (62, 72, 262, 272) formed to be matched to the first concave recesses and coupled to the first concave recesses. 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 (21, 22, 221, 222), each being located in the cap plate and insulated from the cap plate by an insulation member (31, 32) located at a respective terminal hole (H1, H2) of the cap plate, the electrode terminals being connected to respective electrodes of the electrode assembly and extending outside the cap plate wherein each electrode terminal is in a form of a band having a width and a thickness, is welded to an uncoated (11b, 12b) of an electrode of the respective electrode assembly, said uncoated portion consisting of a current collector which is not coated with an active material; and each electrode terminal has a fastening portion projecting outside the case, and the rechargeable battery module further comprises a bus bar (200, 300) connecting two respective said electrode terminals of the unit cells; wherein the fastening portion of each of the electrode terminals receives at least a part of the bus bar; and wherein the rechargeable battery module is in that each said fastening portion includes a first concave recess (41, 51, 241, 251) that is open toward one side of the electrode terminal in a width direction and in that the bus bar (200, 300) includes second concave recesses (62, 72, 262, 272) formed to be matched to the first concave recesses and coupled to the first concave recesses.