During the charging and discharging processes, the following reactions take place in both sides of the cell:
E0= 1.0 V
E0= -0.255 V
V2+ + VO2+ + 2H+ ↔ V3+ + VO2+ + H2O
E0= 1.255 V
Unlike lithium-ion and lead acid batteries, flow batteries work differently. The liquid electrolyte are stored outside the battery in external tanks. This give flow batteries flexibility to design power (which depends on the size of the battery stack) and energy (which depends on the volume of electrolyte stored in tanks) independently. There are different chemistries available in flow batteries, out of which all-vanadium flow battery stores vanadium metal ions at different oxidation states in two tanks. Vanadium flow battery is one of the mature and proven technology in the market and provides more than 25 years of life and stable performance. The working principle is simple. Vanadium has four oxidation states, out of which V2+ and V3+ serve as negative redox couple whereas VO2+(V4+) and VO2+(V5+)serve as positive redox couple. The oxidation states of the vanadium ions continuously changes during charging (V4+ to V5+ and V3+ to V2+) and discharging (V5+ to V4+ and V2+ to V3+) and battery works for infinite cycles with no capacity fade and electrolyte degradation. In addition, V-Flow uses unique additive mixture on the electrolyte that improves the thermal stability and allows to increase the energy density by 25% compared to others.
|Lead Acid Batteries||Lithium ion Batteries||V-Flow Power Cube|
|Lifetime||2-3 years||3-8 years||25 years|
|Environmental & safety issue||Lead is an issue||Highly flammable||No emission,not flammable|
|Energy density (Wh/Kg)||30||100-150||25-30|
|Performance degradation||Yes||Yes||Non degradation, stable performance guarantee|
|Maintenance||Frequent||Frequent||Very low maintenance|
|Storage cost - LCOS($/cycle/Kwh)||0.31||0.21||0.10|
You can find out more about our research and scientific proof of our technology here.