The vanadium redox battery for emergency back-up applications

Secure and reliable power is essential in areas such as telecommunications and information technology to safeguard the vast computer networks which have been established. Uninterruptible power systems have incorporated battery technology to allow smooth power feeding switch-over in the case of a power failure. In such systems lead-acid batteries have commonly been used until generators come online or for safe computer shutdown. A new battery system, the vanadium redox battery is under development at the University of New South Wales, Australia, which provides many advantages over conventional batteries for emergency back-up applications. This system stores all energy in the form of liquid electrolytes which are recirculated around the battery system. The electrolytes can be recharged an indefinite number of times, or the system can be instantly recharged by mechanically exchanging the discharged solution with recharged solution. A vanadium battery emergency back-up system has been designed and tested for operation between a restricted voltage operating range of 22-28 V. The system achieved energy efficiencies above 80% and coulombic and voltage efficiencies as high as 96.4% and 92.2% respectively depending on the load. The system demonstrated excellent performance characteristics with a capacity utilisation up to 94% of theoretical values.