A battery cell includes a stack including C cathode electrodes, A anode electrodes, and S separators, where C, A and S are integers greater than one. A first internal terminal includes a first slot. The external tabs of one of the C cathode electrodes and the A anode electrodes are inserted into the first slot. One of edges of the external tabs of one of the C cathode electrodes and the A anode electrodes are laser welded in the first slot, and portions of the external tabs of the one of the C cathode electrodes and the A anode electrodes extend through the first slot, are folded and laser welded to a surface of the first internal terminal.