A vehicle includes an electric machine, a traction battery pack, and a battery controller. The traction battery pack includes a plurality of cell modules electrically connected with the electric machine. Each of the cell modules includes a housing having a battery cell, a passive circuit element isolated from the battery cell, and a module controller contained therein. The passive circuit elements are electrically connected in series or parallel. The battery controller is in communication with each of the module controllers and is electrically connected with the passive circuit elements. Responsive to signals from the module controllers indicative of a total number of the cell modules and a measured parameter associated with the passive circuit elements being indicative of a same total number of the cell modules, the battery controller operates the battery cells according to power limits defined by the total number.