Fuel cell with electrolyte condensation zone

• US 20070224476A1
• Filed: 05/16/2007
• Published: 09/27/2007
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Hyaxiom Incorporated
• Original Assignee: UTC Power Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Breault, Richard, Fredley, Robert
• Granted Patent: US 8,318,362 B2
• Time in Patent Office: Days
• US Class Current: 429/434
• CPC Class Codes: H01M 8/0258 characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
• CPC Class Codes: H01M 8/0267 having heating or cooling means, e.g. heaters or coolant flow channels
• CPC Class Codes: H01M 8/0271 Sealing or supporting means around electrodes, matrices or membranes
• CPC Class Codes: H01M 8/0276 Sealing means characterised by their form H01M8/0273 takes precedence
• CPC Class Codes: H01M 8/0284 Organic resins; Organic polymers
• CPC Class Codes: H01M 8/0293 Matrices for immobilising electrolyte solutions
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/04119 with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
• CPC Class Codes: H01M 8/04283 Supply means of electrolyte to or in matrix-fuel cells
• CPC Class Codes: H01M 8/086 Phosphoric acid fuel cells [PAFC]
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell 12 has a liquid electrolyte 20, a cathode electrode 28, and an anode electrode 26. The fuel cell includes an electrolyte condensation zone 58 extending from an edge 56 of a first catalyst layer 36 on the cathode electrode to an outer edge 48 of an edge seals 52 and 49. An anode electrode has an anode catalyst layer 30 with an end substantially coinciding with an inner edge 53 of the edge seals. The acid condensation zone is located near the reactant exit, so that electrolyte that has evaporated into the reactant stream can condense out before leaving the fuel cell for re-absorption back into the fuel cell.

Claims

1. A fuel cell comprising:

an electrolyte;

a cathode electrode and an anode electrode;

an electrolyte condensation zone adjacent at least one reactant exit, comprised of a non-reactive area extending from an end of a cathode catalyst layer to an outer edge of the fuel cell; and

an anode catalyst layer that extends across the non-reactive area, wherein an end of the anode catalyst layer is substantially coincident with an inner edge of an edge seal.

2. A fuel cell according to claim 1 wherein the electrolyte is phosphoric acid.

3. A fuel cell according to claim 1 wherein the electrolyte is a free acid contained within a fuel cell having a high temperature electrolyte membrane.

4. A method of operating a fuel cell stack assembly, having at least one fuel cell and containing an electrolyte comprising:

flowing an oxidant through a cathode flow field plate adjacent to a cathode electrode, the cathode electrode having an electrolyte condensation zone adjacent at least one reactant exit comprised of a non-reactive area extending from an end of a cathode catalyst layer to an outside edge of the fuel cell;

flowing a fuel adjacent to an anode electrode, wherein the anode electrode has an anode catalyst layer extending across the non-reactive area with an end substantially coincident with an inner edge of an edge seal; and

flowing a coolant through at least one coolant channel in the fuel cell stack assembly.

5. A method according to claim 4, wherein the electrolyte is phosphoric acid.

6. A method according to claim 4 wherein the electrolyte is a free acid contained within a fuel cell having a high temperature electrolyte membrane.

7. A method according to claim 4, wherein the coolant enters the fuel cell stack assembly adjacent the electrolyte condensation zone.

8. A method according to claim 4, wherein there is a greater number of coolant passages in the area adjacent the acid condensation zone than adjacent a reactive portion of the fuel cell.

9. A fuel cell comprising:

an electrolyte;

a cathode electrode and an anode electrode;

the cathode electrode having an electrolyte condensation zone comprised of a non-reactive area adjacent at least one reactant exit, extending from an end of a cathode catalyst layer to an outer edge of the fuel cell; and

wet seal material that inhibits the reduction of oxygen at an outer surface of the fuel cell.

10. A fuel cell according to claim 9, wherein the electrolyte is phosphoric acid.

11. A fuel cell according to claim 9 wherein the electrolyte is a free acid contained within a fuel cell having a high temperature electrolyte membrane.

12. A fuel cell according to claim 9, wherein the wet seal materials are selected from the group comprising tungsten oxide, silicon carbide, and mixtures thereof.

13. A fuel cell comprising:

an electrolyte;

a cathode electrode and an anode electrode;

the cathode electrode having an electrolyte condensation zone comprised of a non-reactive area adjacent at least one reactant exit, extending from an end of a cathode catalyst layer to an outer edge of the fuel cell; and

a solid edge seal.

14. A fuel cell according to claim 13 wherein the solid edge seal is formed from a material selected from the group comprising polymers and graphite polymeric composites.

15. A fuel cell according to claim 13, wherein the electrolyte is phosphoric acid.

16. A fuel cell according to claim 13 wherein the electrolyte is a free acid contained within a fuel cell having a high temperature electrolyte membrane.