Technologies
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Vanadium Redox Batteries
Description:Vanadium Redox Batteries store energy by employing vanadium redox couples (V2+/V3+ in the negative and V4+/V5+ in the positive half-cells). These are stored in mild sulfuric acid solutions (electrolytes).
During the charge/ discharge cycles, H+ ions are exchanged between the two electrolyte tanks through the hydrogen-ion permeable polymer membrane. The cell voltage is 1.4-1.6 volts. The net efficiency of this battery can be as high as 85%. Like other flow batteries, the power and energy ratings of Vanadium Redox Batteries are independent of each other.
Deployment Status: 
Vanadium Redox Batteries were pioneered in the Australian University of New South Wales (UNSW) in early 1980’s. The Australian Pinnacle Vanadium Redox Batteries bought the basic patents in 1998 and licensed them to Sumitomo Electric Industries (SEI) and VRB Power Systems. Vanadium Redox Batteries storage up to 500kW, 10 hrs (5MWh) have been installed in Japan by SEI. Vanadium Redox Batteries have also been applied for power quality applications (3MW, 1.5 sec., SEI).
Current Developers / Suppliers:
Prudent Energy
Past Developers/Suppliers:
VRB Power Systems, Inc.
Reliable Power
Pinnacle VRB
Sumitomo Electric Industries, Ltd.
Cellennium Company Limited