James Conca, “Forbes” contributor
Dec 13, 2016,
The latest, greatest utility-scale battery storage technology to emerge on the commercial market is the vanadium redox battery, also known as the vanadium flow battery.
V-flow batteries are fully containerized, nonflammable, compact, reusable over semi-infinite cycles, discharge 100% of the stored energy and do not degrade for more than 20 years.
Most batteries use two chemicals that change valence (or charge or redox state) in response to electron flow that convert chemical energy to electrical energy, and vice versa. V-flow batteries use the multiple valence states of just vanadium to store and release charges.
V can exist as several ions of different charges in solution, V(2+,3+,4+,5+), each having different numbers of electrons around the nucleus. Fewer electrons gives a higher positive charge. Energy is stored by providing electrons making V(2+,3+), and energy is released by losing electrons to form V(4+,5+).
Flow batteries consist of two tanks of liquid, which simply sit there until needed. When pumped into a reactor, the two solutions flow adjacent to each other past a membrane and generate a charge by moving electrons back and forth during charging and discharging.