VRd batteries store energy by employing vanadium redox couples dissolved in mild sulfuric acid solutions (electrolytes). During charge and discharge, hydrogen ions are exchanged between the two electrolyte tanks through a hydrogen-ion-permeable polymer membrane. The net efficiency of this battery can be as high as 85%. Like other flow batteries, the power and energy ratings of VRd batteries are independent of each other.
VRd technology was pioneered at Australia’s University of New South Wales (UNSW) in the early 1980s. VRd battieres rated up to 500 kW/5 MWh) have been installed in Japan by Sumitomo Electric Industries (SEI). VRd batteries have also been applied for power quality applications (supplying up to 3 MW for 1.5 seconds).
Updated April 2010
Sumitomo Electric Industries