A traction battery assembly includes, among other things, a battery cell array having a plurality of individual battery cells. The battery cell array usable with a first busbar module having a first arrangement of busbars. The battery cell array is also usable with a second busbar module having a second arrangement of busbars. When the battery cell array is used with the first busbar module, the battery cell array is partitioned into a first number of groups of battery cells in parallel with each other. When the battery cell array is used with the second busbar module, the battery cell array is partitioned into a different, second number of groups of battery cells in parallel with each other.