Novel electrolyte rebalancing method for vanadium redox flow batteries

• A novel electrolyte rebalancing method for vanadium redox flow batteries is presented. The uses a cell fed from the positive tank. reduces concentration of V(V) ions in catholyte. multi-physical numerical model used to control and optimize process. effectiveness has been tested validated on real VRFB. new proposed that restores battery energy capacity Vanadium Redox Flow Battery, by counteracting charge imbalance caused air-oxidation hydrogen evolution negative electrolyte. process makes use regeneration system specifically designed successfully tested. This built around an electrolysis cell, called “regeneration cell”, where electro-reduction reaction coupled with oxygen catalyzed Ti-IrO 2 electrode. three different unbalanced electrolytes was tested: V 3.55+ , 3.60+ 3.65+ namely: 45% V(III)/55% V(IV), 40% V(III)/60% V(IV) 35% V(III)/65% respectively. behavior VRFB during investigated both numerically experimentally. An end-point strategy without additional sensors developed using specific mathematical capable simulating current response concentrations profile allowed improve performance After rebalancing, resulting oxidation states were respectively: 3.483+ 3.482+ 3.484+ . Since perfectly balanced 3.50+ (50% V(III), 50% (VIV) such results demonstrated drastically reduced successful.