Ferric ion reduction system to enable electrolyte rebalance within an iron flow battery

An iron redox flow battery system comprising:

• a cathode cell having a first electrode;
• an anode cell having a second electrode;
• a membrane separating the cathode cell and the anode cell;
• a first electrolyte tank with a catholyte, the first electrolyte tank in fluid communication with the cathode cell;
• a second electrolyte tank with an anolyte, the second electrolyte tank in fluid communication with the anode cell;
• a first rebalancing cell in fluid communication between the cathode cell and the first electrolyte tank, the first rebalancing cell configured to reduce active species from the catholyte;
• and,
• a second rebalancing cell in fluid communication with the first electrolyte tank and the second electrolyte tank such that the first electrolyte tank and the second electrolyte tank are in direct fluid communication, the second rebalancing cell configured to reduce active species from the catholyte;
• a monitoring device configured to provide an obtained value relating to a condition of the catholyte, or the anolyte, or both;
• and,
• a controller in communication with the monitoring device, the controller comprising non- transitory computer-readable media storing executable instructions that, when executed, cause the controller to:
• compare the obtained value against a threshold value;
• and
• when the obtained value is above or below a threshold, displace a volume of the catholyte from the first electrolyte tank to the second rebalancing cell to reduce ferric cations in the catholyte.