Battery module, a battery pack, an electric vehicle, and a method of mounting a battery module

A battery module includes a plurality of secondary battery cells and a negative current collector. Each of the secondary battery cells includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a case accommodating the electrode assembly, a positive terminal electrically connected to the positive electrode, and a negative terminal electrically connected to the negative electrode. The case of each of the plurality of secondary battery cells has a groove that is part of the negative terminal. The negative current collector includes a negative connection portion mechanically and electrically connected with a first one of the plurality of secondary battery cells by a first press fit connection in the groove of the case.