A battery cell holder is disclosed. In one embodiment, the holder includes first and second outer frames respectively positioned at first and second sides of a plurality of battery cells arranged substantially parallel with each other, wherein the first and second sides are opposing each other, and wherein the outer frames comprise first and second outer fastening members, respectively. The cell holder may further include at least one inner frame disposed between the outer frames, wherein the at least one inner frame comprises a first inner frame adjacent to the first outer frame, wherein the first inner frame has first and second inner fastening members which are respectively formed at opposing sides thereof and have corresponding shapes with respect to each other. The first inner fastening member may be connected to the first outer fastening member.