A battery system including: a plurality of subunits each of which has a heatsink and a battery cell and two voltage terminals symmetrically positioned with respect to a centerline of that battery cell, wherein all of the battery cells are arranged so that their voltage terminals are aligned along two rows; a plurality of identical busbar supports equal in number to the plurality of subunits, each having two slots and mounted on a corresponding different one of the subunits with each of the terminals of the battery cell extending up through the two slots; and a plurality of bimetallic busbars, each one supported by a different corresponding subset of the busbar supports and electrically connected directly to either a first or second terminal of each of the battery cells of each of the modules on which those busbar supports are mounted.