US Patent 6841294 Electrolyte rebalancing system

A process for rebalancing the electrolyte system in a regenerative fuel cell using a sulfide/polysulfide reaction in one half of the cell and a bromine/bromide reaction in the other half of the cell comprises passing the electrolyte containing sulfide/polysulfide or bromine/bromide through the +ve chamber of an auxiliary cell and passing an electrolyte containing water and being free from polysulfide or bromine through the −ve chamber of the auxiliary cell the auxiliary cell operating so as to oxidize sulfide ions to sulfur or bromide ions to bromine in the +ve chamber and to reduce water to hydrogen and hydroxide ions in the −ve chamber.