Metal electrode assembly for flow batteries

1. A flow battery electrode assembly comprising:

a first impermeable, substantially metal electrode consisting essentially of a metal;

a second permeable, substantially metal electrode; and

at least one electrically conductive spacer connecting the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode such that the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode are spaced apart from each other by an electrolyte flow path;

wherein the at least one electrically conductive spacer comprises a plurality of electrically conductive spacers which mechanically and electrically connect the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode.

2. The flow battery electrode assembly of claim 1 , wherein:

the first impermeable, substantially metal electrode consists essentially of a platable metal plate or the platable metal plate that is plated with a layer of zinc; and

the second permeable, substantially metal electrode comprises pure metal, metal alloy or cermet electrode.

3. The flow battery electrode assembly of claim 2 , wherein the first impermeable, substantially metal electrode comprises a cathode electrode, and the second permeable, substantially metal electrode comprises a transition metal with a deposited or alloyed surface coating comprising noble metal anode electrode.

4. The flow battery electrode assembly of claim 3 , wherein:

the cathode electrode comprises a zinc, aluminum plated titanium, titanium, or tantalum electrode; and

the anode electrode comprises a ruthenium or iridium coated titanium or tantalum electrode.

5. The flow battery electrode assembly of claim 1 , wherein the second permeable, substantially metal electrode comprises at least one of metal felt, metal foam, metal screen, metal mesh, metal plate with holes, metal woven fabric, metal wool, permeable sintered metal powder, packed metal powder, or packed metal powder in a porous container.

6. The flow battery electrode assembly of claim 1 , wherein the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode are mechanically and electrically connected using the at least one electrically conductive spacer.

7. The flow battery electrode assembly of claim 6 , wherein the at least one electrically conductive spacer comprises a spring configured to be compressed.

8. The flow battery electrode assembly of claim 6 , wherein the at least one electrically conductive spacer is integral with at least one of the first impermeable, substantially metal electrode or the second permeable, substantially metal electrode.

9. The flow battery electrode assembly of claim 1 , wherein the plurality of electrically conductive spacers comprise flow directors which separate the electrolyte flow path into a plurality of electrolyte flow channels between the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode.

10. The flow battery electrode assembly of claim 9 , wherein the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode are rectangular shaped and the plurality of electrically conductive spacers extend in a substantially parallel direction to form a plurality of substantially parallel electrolyte flow channels.

11. The flow battery electrode assembly of claim 9 , wherein the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode are connected to the plurality of spacers by welds.

12. The flow battery electrode assembly of claim 9 , wherein the plurality of electrically conductive spacers comprise stamped protrusions in a battlement shaped first impermeable, substantially metal electrode, such that the stamped protrusions are connected to the second permeable, substantially metal electrode.

13. The flow battery electrode assembly of claim 9 , wherein the plurality of electrically conductive spacers comprise integrally formed protrusions in the second permeable, substantially metal electrode, such that the protrusions are connected to the first impermeable, substantially metal electrode.

14. The flow battery electrode assembly of claim 1 , wherein the electrode assembly is located in a central opening in an electrically insulating frame which supports the first impermeable, substantially metal electrode and the second permeable, substantially metal electrodes.

15. The flow battery electrode assembly of claim 14 , wherein the frame comprises a disc shaped or polygonal plate shaped frame comprising:

at least a first and a second electrolyte flow manifolds;

a first set of flow channels on a first surface of the frame connecting the first manifold with the central opening;

a second set of flow channels on an opposite, second surface of the frame connecting the second manifold with the central opening.

16. A flow battery comprising:

a vessel;

a stack of electrochemical cells comprising a plurality of the electrode assemblies of claim 1 located in the vessel;

a reservoir located in the vessel, the reservoir configured to accumulate a metal-halide electrolyte; and

a flow circuit located in the vessel, the flow circuit configured to deliver the metal-halide electrolyte between the reservoir and the stack of electrochemical cells.

17. The flow battery of claim 16 , wherein:

the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode are electrically connected in series to electrically connect in series the electrochemical cells in the stack;

the stack of electrochemical cells comprises a first electrochemical cell and an adjacent second electrochemical cell;

a cathode electrode of the first electrochemical cell comprises the first impermeable, substantially metal electrode;

an anode electrode of the second electrochemical cell comprises the second permeable, substantially metal electrode;

the at least one electrically conductive spacer connects the cathode electrode of the first electrochemical cell to the anode electrode of the second electrochemical cell;

an anode electrode of the first electrochemical cell is separated from the cathode electrode of the first electrochemical cell by a reaction zone of the first electrochemical cell; and

a cathode electrode of the second electrochemical cell is separated from the anode electrode of the second electrochemical cell by a reaction zone of the second electrochemical cell.

18. A flow battery electrode assembly comprising:

a first impermeable, substantially metal electrode;

a second permeable, substantially metal electrode; and

at least one electrically conductive spacer connecting the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode such that the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode are spaced apart from each other by an electrolyte flow path;

wherein the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode are mechanically and electrically connected using the at least one electrically conductive spacer; and

wherein the at least one electrically conductive spacer comprises a plurality of electrically conductive spacers which mechanically and electrically connect the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode.

19. The flow battery electrode assembly of claim 18 , wherein:

the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode comprise greater than 50% metal by volume; and

the second permeable, substantially metal electrode comprises pure metal, metal alloy or cermet electrode.

20. The flow battery electrode assembly of claim 19 , wherein:

the first impermeable, substantially metal electrode comprises a cathode electrode;

the second permeable, substantially metal electrode comprises an anode electrode,

the cathode electrode comprises a zinc, aluminum plated titanium, titanium, or tantalum electrode; and

the anode electrode comprises a ruthenium or iridium coated titanium or tantalum electrode.

21. The flow battery electrode assembly of claim 18 , wherein the second permeable, substantially metal electrode comprises at least one of metal felt, metal foam, metal screen, metal mesh, metal plate with holes, metal woven fabric, metal wool, permeable sintered metal powder, packed metal powder, or packed metal powder in a porous container.

22. The flow battery electrode assembly of claim 18 , wherein the plurality of electrically conductive spacers comprise flow directors which separate the electrolyte flow path into a plurality of electrolyte flow channels between the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode.

23. The flow battery electrode assembly of claim 22 , wherein the adjacent first impermeable, substantially metal electrode and second permeable, substantially metal electrode are rectangular shaped and the plurality of electrically conductive spacers extend in a substantially parallel direction to form a plurality of substantially parallel electrolyte flow channels.

24. The flow battery electrode assembly of claim 18 , wherein the electrode assembly is located in a central opening in an electrically insulating frame which supports the first impermeable, substantially metal electrode and the second permeable, substantially metal electrodes.

25. The flow battery electrode assembly of claim 24 , wherein the frame comprises a disc shaped or polygonal plate shaped frame comprising:

at least a first and a second electrolyte flow manifolds;

a first set of flow channels on a first surface of the frame connecting the first manifold with the central opening;

a second set of flow channels on an opposite, second surface of the frame connecting the second manifold with the central opening.

26. A flow battery comprising:

a vessel;

a stack of electrochemical cells comprising a plurality of the electrode assemblies of claim 18 located in the vessel;

a reservoir located in the vessel, the reservoir configured to accumulate a metal-halide electrolyte; and

a flow circuit located in the vessel, the flow circuit configured to deliver the metal-halide electrolyte between the reservoir and the stack of electrochemical cells.

27. The flow battery of claim 26 , wherein:

the first impermeable, substantially metal electrode and the second permeable, substantially metal electrode are electrically connected in series to electrically connect in series the electrochemical cells in the stack;

the stack of electrochemical cells comprises a first electrochemical cell and an adjacent second electrochemical cell;

a cathode electrode of the first electrochemical cell comprises the first impermeable, substantially metal electrode;

an anode electrode of the second electrochemical cell comprises the second permeable, substantially metal electrode;

the at least one electrically conductive spacer connects the cathode electrode of the first electrochemical cell to the anode electrode of the second electrochemical cell;

an anode electrode of the first electrochemical cell is separated from the cathode electrode of the first electrochemical cell by a reaction zone of the first electrochemical cell; and

a cathode electrode of the second electrochemical cell is separated from the anode electrode of the second electrochemical cell by a reaction zone of the second electrochemical cell.