A battery pack includes a plurality of battery modules that includes a plurality of battery cells, a battery cell holder, a second-electrode assembly including a plurality of second-electrode bus bar plates, a first-electrode assembly, and a cover. The first-electrode assembly includes a plurality of first-electrode bus bar plates, a first-electrode terminal, a second-electrode terminal connected to one of the plurality of second-electrode bus bar plates, and an inter-electrode bus bar connecting the second-electrode bus bar plate and one of the first-electrode bus bar plate and the first-electrode terminal. The first-electrode assembly is in a first pattern or a second pattern. An arrangement of the first-electrode terminal and the second-electrode terminal in the battery module differs according to the pattern of the first-electrode assembly.