Energy storage devices, battery cells, and batteries of the present technology may include a first battery cell. The first battery cell may include an anode current collector, and an anode active material disposed on the anode current collector. The first battery cell may include a cathode current collector and a cathode active material disposed on the cathode current collector. The current collectors may be polymeric materials. The batteries may include a first conductive band electrically coupled with the first battery cell. The first conductive band may be seated on the second surface of one of the anode current collector or the cathode current collector. The first conductive band may extend about a perimeter of the one of the anode current collector or the cathode current collector. The batteries may include a cell module including a first flexible extension electrically coupled with the first conductive band.