Fuel cell stacks and methods

• US 20090004547A1
• Filed: 06/28/2007
• Published: 01/01/2009
• Est. Priority Date: 06/28/2007
• Status: Active Grant

• Current Assignee: Ballard Unmanned Systems, Inc. (Honeywell International Inc.)
• Original Assignee: Protonex Technology Corporation (Honeywell International Inc.)
• Inventors: Baldic, Jeff, Osenar, Paul, Avis, Seth, Lauder, Nick, Rezac, Ronald, Vitella, Thomas
• Granted Patent: US 8,580,457 B2
• Time in Patent Office: Days
• US Class Current: 429/457
• CPC Class Codes: H01M 8/0247 characterised by the form characterised by a channel configuration H01M8/0258
• CPC Class Codes: H01M 8/0263 having meandering or serpentine paths
• 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 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: H01M 8/2483 characterised by internal manifolds
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

The invention provides a fuel cell stack including a layer of encapsulating material disposed about the separator plate, MEA, and reactant manifold, wherein the reactant manifold is bounded at least in part by the encapsulating material. The fuel cell stack also includes a first opening through the plate body to the first face from the second face, and an open channel in the second face extending from the opening toward a periphery of the plate. The invention also provides a fuel cell stack having a first face including an opening for passage of a reactant therethrough, a first reactant flow field defined thereon, and a first raised surface formed thereon substantially surrounding the opening. The first raised surface is configured and adapted to mate with a second surface on a face of an adjacent plate to create a flow obstruction for encapsulating material.

Claims

1. A fuel cell stack comprising:

a) at least one bipolar plate assembly including a first generally planar plate body having a first generally planar face, the first face including;

i) an opening defined by the first plate body for passage of a reactant therethrough;

ii) a first reactant flow field defined thereon; and

iii) a first raised surface on the first face substantially surrounding the opening, the first raised surface being adapted and configured to mate with a second surface on a face of an adjacent bipolar plate assembly, wherein the first raised surface and second surface create a flow obstruction when the raised surfaces are mated;

b) a first membrane electrode assembly in operable communication with the first reactant flow field;

c) a reactant manifold in fluid communication with the reactant flow field by way of a first fluid flow path, the reactant manifold being adapted and configured to facilitate transport of a reactant through the fuel cell stack; and

d) a layer of encapsulating material disposed about the separator plate, membrane electrode assembly and reactant manifold, wherein the encapsulating material is substantially prevented from flowing into the opening defined by the first plate body by the flow obstruction.

2. The fuel cell stack of claim 1, wherein the flow obstruction is adapted and configured to permit a gas flow therethrough prior to encapsulating material being incorporated into the stack.

3. The fuel cell stack of claim 1, wherein the flow obstruction is adapted and configured to substantially prohibit a gas flow therethrough prior to encapsulating material being incorporated into the stack.

4. The fuel cell stack of claim 1, wherein the first raised surface includes material that is an electrical insulator.

5. The fuel cell stack of claim 1, wherein the first raised surface is composed of a material different from the first plate body and second plate body.

6. The fuel cell stack of claim 1, wherein the flow obstruction includes an o-ring surrounding the opening.

7. The fuel cell stack of claim 1, wherein the first raised surface constitutes a monolithic structure in combination with the first plate body.

8. The fuel cell stack of claim 1, wherein the first raised surface is generally ring shaped.

9. The fuel cell stack of claim 1, wherein the first raised surface fully surrounds the opening.

10. The fuel cell stack of claim 1, wherein the first raised surface includes at least one interruption therein along its extent.

11. The fuel cell stack of claim 1, further comprising a second raised surface substantially surrounding the opening.

12. The fuel cell stack of claim 11, wherein the second raised surface substantially surrounds the first raised surface.

13. A method of making a fuel cell stack comprising:

a) providing a first bipolar plate assembly body having a first generally planar face, the first face including;

i) a first opening defined by the first plate body for passage of a reactant therethrough;

ii) a first reactant flow field defined on the first face; and

iii) a first raised surface on the first face substantially surrounding the first opening;

b) disposing a first side of a first membrane electrode assembly in communication with the first reactant flow field;

c) disposing a second bipolar plate assembly having a second generally planar face in communication with a second side of the membrane electrode assembly to form a stack, the second face including;

i) a second opening defined by the second plate body for passage of a reactant therethrough;

ii) a second reactant flow field defined on the second face; and

iii) a receiving surface on the second face substantially surrounding the opening, wherein the first raised surface and receiving surface interfit to define a flow obstruction; and

d) encapsulating the stack in an encapsulating material, wherein the encapsulating material is substantially prevented from flowing into the opening defined by the first plate body by the flow obstruction.

14. The method of claim 13, wherein the flow obstruction is adapted and configured to permit a gas flow therethrough prior to encapsulating material being incorporated into the stack.

15. The method of claim 13, wherein the flow obstruction is adapted and configured to substantially prohibit a gas flow therethrough prior to encapsulating material being incorporated into the stack.

16. The method of claim 13, wherein the first raised surface includes material that is an electrical insulator.

17. The method of claim 13, wherein the first raised surface is composed of a material different from the first plate body and second plate body.

18. The method of claim 13, wherein the flow obstruction includes an o-ring surrounding the opening.

19. The method of claim 13, wherein the first raised surface constitutes a monolithic structure in combination with the first plate body.

20. The method of claim 13, wherein the first raised surface is generally ring shaped.