Characteristics and performance of 1 kW UNSW vanadium redox battery

Energy efficiencies of up to 90% are reported for the 1 kW prototype vanadium redox battery being developed at the University of NSW. Solutions of 1.5–2 M vanadium sulphate in sulphuric acid are employed in both 12-cells, and over 85% of theoretical capacity can be utilised at discharge currents ranging from 30 to 120 A. Energy losses of 2–3% are expected for pumping of electrolytes, so that overall energy efficiencies of 87–88% should be achieved. The vanadium battery thus continues to show great promise as one of the most efficient energy storage systems. The battery has already undergone over 100 charge—discharge cycles and further long-term testing is currently being undertaken.