Technology attributes
Other attributes
The vanadium redox battery (VRB), also known as the vanadium flow battery (VFB) or vanadium redox flow battery (VRFB), is a type of rechargeable flow battery that employs vanadium ions in different oxidation states to store chemical potential energy. The Vanadium Redox Flow Battery is an energy storage flow battery invented by Professor Maria Skyllas-Kazacos in the 1980's
The vanadium redox battery exploits vanadium's ability to exist in solution in four different oxidation states, and uses this property to make a battery with one electroactive element instead of two. The Vanadium Redox Flow Battery is suitable for large-scale energy storage, including but not limited to utility, commercial, industrial and residential applications. Some of the Vanadium Redox Flow Battery's characteristics make it a good technology for energy storage, including having no "thermal runaway" risk, which causes a fire in a battery, and is an inherent risk of solid-state batteries and lithium-ion batteries.
Vanadium redox battery use multiple valence states of vanadium to store and release charge
The vanadium redox battery offers almost unlimited energy capacity by using larger electrolyte storage tanks. The battery be left completely discharged for long periods with no ill effects. If the electrolytes are accidentally mixed, the battery suffers no permanent damage, and a single state of charge between the two electrolytes avoids the capacity degradation that occurs in the single cell in non-flow batteries. The vanadium redox electrolyte is aqueous and non-flammable, and the generation 3 formulation using a mixed acid solution developed by the Pacific Northwest National Laboratory operates over a wider temperature range allowing for passive cooling.
Vanadium redox batteries have long cycle lives: producers specify cycle durability in excess of 15,000-20,000 charge/discharge cycles. These compare to the cycle lives of solid-state batteries, usually around 4,000-5,000 charge/discharge cycles. Consequently, the cost of energy of vandium redox batteries is in around a few tens of $ cents or € cents, and close to the targets of $0.05 and €0.05, stated by the US Department of Energy and the European Commission Strategic Energy Technology (SET) Plan.
The main disadvantages with vanadium redox technology are a relatively poor energy-to-volume ratio in comparison with standard storage batteries, and the relatively poor round trip efficiency. Furthermore, the aqueous electrolyte makes the battery heavy and therefore only useful for stationary applications.
The possibility of creating a vanadium flow battery was explored by P.A. Pissoort in the 1930s, NASA researchers in the 1970s, and A. Pellegri and P.M. Spaziante in the 1970s, but they were unsuccessful in demonstrating the technology. The first successful demonstration of the all-vanadium redox flow battery which employed vanadium in a solution of sulfuric acid in each half was by Maria Skyllas-Kazacos at the University of New South Wales in the 1980s. Her design used sulfuric acid electrolytes, and was patented by the University of New South Wales in Australia in 1986.
Numerous companies and organizations involved in funding and developing vanadium redox batteries include Avalon Battery, Vionx, UniEnergy Technologies, Ashlawn Energy, RedT Energy, CellCube, Rongke Power, Prudent Energy, H2, Inc., Australian Vanadium, Sumitomo Electric and Imergy.
