Scale-up of Interdigitated Design from Small Cell to Large Cell for Aqueous Redox Flow Batteries

Abstract

Redox flow batteries present attributes for large-scale energy storage. Interdigitated flow configuration is a promising structure due to its higher power density and lower pressure loss. The screening for new electrolyte is usually first tested on small cell (<10 cm2) due to its easy operation and less electrolyte consumption. To test the electrolyte functionality in practical application condition, large-scale (i.e., 780 cm2) testing is required conventionally in laboratory or industry. The twice testing is due to the fact that the testing results in small cell are different from that for large-scale interdigitated cell. In order to reduce the testing cycles and quickly estimate the application of new electrolytes, scale-up of interdigitated design from small cell to large cell is investigated in this work.Numerical simulation on different scales of interdigitated cells (10cm2, 78cm2, 130cm2, 780cm2) is conducted to assess the polarization. The local velocity distribution and redox-active species concentration are extracted to show their dominance on the cell performance. It is shown that with similar velocity and concentration distribution, cell with different scales present similar limiting current density and power density, regardless of active area. It implies that the results in small cells can be directly scaled up for large cells without further testing. It provides an avenue for quick estimation of new electrolyte in application condition.Experimental testing is conducted on vanadium redox flow battery for different scale of interdigitated cell. The experimental results will demonstrate this scale-up from small-scale to middle-scale interdigitated cell.