The resistance in the stacks was calculated from the IR drop at the GCD curves. As expected, increasing the number of pairs in the stack increases the overall resistance (from 35 to 152 Ω•cm 2 ) and the energy loss (from 21 to 47 J) in the modules, which is consistent with the trends observed in EIS. The resistance per electrode pair at 1V decreased from 19 to 13 Ω•cm 2 with increasing cell number, which also leads to an increased round-trip energy efficiency from 67% to 84%, and an improved energy consumption from 142 to 60 kJ•mol -1 . This phenomenon can be explained by the different current flow pattern within a bipolar electrode compared to a (monopolar) end electrode. In an SSA module with a single cell, current flows in-plane within the current collector plate, and then into the electrode. In a bipolar electrode, the current flows directly through-plane from one electrode end through the Ti foil to the other end of the bipolar electrode. The resistance is lower in the bipolar electrode because the resistor length is shorter, and the resistor area is larger. With increasing number of electrode pairs, the fraction of the bipolar electrode pairs in the stack increases from 1:2 (50%) to 11:12 (91.7%) leading to lower energy consumption. This suggests that a further increase in the number of bipolar electrodes should lead to even lower energy consumption. Overall, scaling SSA modules via the introduction of bipolar electrodes appeals as an effective strategy to minimize the energy consumption in SSA.