Flow battery with interdigitated flow field

1. A redox flow battery comprising:

a first liquid-porous electrode;

a second liquid-porous electrode spaced apart from the first liquid-porous electrode;

an ion-exchange membrane arranged between the first liquid-porous electrode and the second liquid-porous electrode;

first and second flow fields adjacent the respective first liquid-porous electrode and second liquid-porous electrode, each of the first and second flow fields including first channels having at least partially blocked outlets and second channels having at least partially blocked inlets, and the second channels are interdigitated with the first channels; and

a positive electrolyte storage tank connected in a positive recirculation loop with one of the first or second flow fields and a negative electrolyte storage tank connected in a negative recirculation loop with the other of the first or second flow fields.

2. The flow battery as recited in claim 1 , wherein the first and second flow fields are respective bipolar plates, and the first channels and the second channels extend partially through the thickness of the respective bipolar plates such that each channel includes a bottom wall, two sidewalls and an open top that is adjacent to the respective first liquid-porous electrode or second liquid-porous electrode.

3. The flow battery as recited in claim 1 , wherein the first channels and the second channels each define flow passages between elongated ribs, and the first channels include first obstruction members that at least partially block the outlets of the first channels and the second channels include second obstruction numbers that at least partially block the inlets of the second channels, and the first obstruction members and the second obstruction members extend into the flow passages.

4. The flow battery as recited in claim 1 , wherein the first channels include first obstruction members that fully block the outlets of the first channels, and the second channels include second obstruction members that fully block the inlets of the second channels.

5. The flow battery as recited in claim 1 , wherein the first and second flow fields further comprise third channels that are located either upstream or downstream relative to the first channels and the second channels, and the third channels are unobstructed.

6. The flow battery as recited in claim 1 , wherein the first channels and the second channels each include chambers having at least partially blocked chamber inlets and at least partially blocked chamber outlets.

7. The flow battery as recited in claim 1 , wherein the first channels and the second channels each include chambers having fully blocked chamber inlets and fully blocked chamber outlets.

8. The flow battery as recited in claim 1 , wherein the first liquid-porous electrode and the second liquid-porous electrode are each porous carbon.

9. The flow battery as recited in claim 8 , wherein the porous carbon includes a catalyst material.

10. The flow battery as recited in claim 1 , wherein each of the first liquid-porous electrode and the second liquid-porous electrode have a thickness of less than 2 millimeters.

11. The flow battery as recited in claim 10 , wherein the thickness is 0.25-0.75 millimeters.

12. The flow battery as recited in claim 1 , wherein the first liquid-porous electrode, the second liquid-porous electrode, the ion-exchange membrane, and the first and second flow fields are a cell unit, and the flow battery includes a stack of the cell units.

13. A method for use with a redox flow battery, the method comprising

providing a flow battery that includes a first liquid-porous electrode, a second liquid-porous electrode spaced apart from the second liquid-porous electrode, an ion-exchange membrane arranged between the first liquid-porous electrode and the second liquid-porous electrode, and first and second flow fields adjacent the respective first liquid-porous electrode and second liquid-porous electrode, each of the first and second flow fields including first channels having at least partially blocked outlets and second channels having at least partially blocked inlets, and the second channels are interdigitated with the first channels, a positive electrolyte storage tank connected in a positive recirculation loop with one of the first or second flow fields, and a negative electrolyte storage tank connected in a negative recirculation loop with the other of the first or second flow fields; and

restricting flow of a liquid electrolyte through the first channels using the at least partially blocked outlets of the first channels to force flow of the liquid electrolyte though the adjacent respective first liquid-porous electrode or second liquid-porous electrode into an adjacent second channel.

14. The method as recited in claim 13 , further comprising flowing the liquid electrolyte into a chamber in the adjacent second channel, the chamber having an at least partially blocked chamber inlet and an at least partially blocked chamber outlet.

15. The method as recited in claim 14 , further comprising flowing the liquid electrolyte into an adjacent first channel from the second channel through the respective adjacent first or second liquid-porous electrode.

16. A redox flow battery comprising:

at least one cell including,

a first liquid-porous electrode;

a second liquid-porous electrode spaced apart from the first liquid-porous electrode;

an ion-exchange membrane arranged between the first liquid-porous electrode and the second liquid-porous electrode; and

a first flow field adjacent the first liquid-porous electrode opposite the ion-exchange membrane and a second flow field adjacent the second liquid-porous electrode opposite the ion-exchange membrane, each of the first and second flow fields including first channels having at least partially blocked outlets and second channels having at least partially blocked inlets, and the second channels are interdigitated with the first channels; and first and second electrolyte storage tanks connected in respective first and second recirculation loops with the at least one cell.

17. The flow battery as recited in claim 16 , further comprising first and second electrolyte storage tanks external of the at least one cell and connected in respective first and second recirculation loops with the respective first and second liquid-porous electrodes.