Hybrid redox fuel cell system

A method of operating a hybrid redox fuel cell system, the method comprising:

• flowing a reductant through an anode side of a hybrid redox fuel cell of the hybrid redox fuel cell system, and flowing a liquid electrolyte through a cathode side of the hybrid redox fuel cell, wherein the liquid electrolyte includes a metal ion at a higher oxidation state and the metal ion at a lower oxidation state;
• directing the liquid electrolyte from the cathode side to a catalyst bed, wherein the catalyst bed includes a substrate later and a catalyst layer;
• spiral winding the substrate layer with the catalyst layer into a jelly roll structure to form the catalyst bed;
• and
• reducing the metal ion at the higher oxidation state to the lower oxidation state at the cathode side while oxidizing the reductant at the anode side to generate power at the hybrid redox fuel cell.

A hybrid redox fuel cell system, comprising:

• a hybrid redox fuel cell including an anode side through which a reductant is flowed and a cathode side through which a liquid electrolyte is flowed;
• a catalyst bed fluidly connected to the cathode side, the catalyst bed including a substrate layer spiral wound with a catalyst layer into a jelly roll structure, wherein,
• the liquid electrolyte includes a metal ion at a higher oxidation state and the metal ion at a lower oxidation state, and
• power is generated at the hybrid redox fuel cell by way of reducing the metal ion at the higher oxidation state to the lower oxidation state at the cathode side while oxidizing the reductant at the anode side;
• and
• a controller including instructions stored in non-transitory memory therein, the instructions executable to:
• balance a rate of reduction of the metal ion at the higher oxidation state in the cathode side with a rate of regeneration of the metal ion at the higher oxidation state in the catalyst bed, wherein balancing the rate of reduction with the rate of regeneration comprises:
• determining, via sensors, if the rate of reduction and the rate of regeneration are imbalanced;
• responsive to the rate of regeneration being less than the rate of reduction, increasing a flow rate of a recycle flow control device, wherein the recycle flow control device recycles an effluent from the catalyst bed to an inlet of the catalyst bed, and/or increasing a flow of a gas reactant from a regeneration gas source to the catalyst bed;
• responsive to the rate of regeneration being greater than the rate of reduction, decreasing the flow rate of the recycle flow control device and/or decreasing the flow of the gas reactant from the regeneration gas source to the catalyst bed.