A CLAMP ASSEMBLY FOR A FUEL CELL STACK AND A METHOD OF ASSEMBLING A FUEL CELL STACK

• US 20170025701A1
• Filed: 10/28/2014
• Published: 01/26/2017
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: University Of Cape Town
• Original Assignee: University Of Cape Town
• Inventors: Tanaka, Shiro
• Granted Patent: US 10,454,126 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 8/248 Means for compression of the fuel cell stacks
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A clamp assembly for securing a fuel cell stack arrangement in a compressed condition. The stack includes an electrode assembly interposed between upper and lower current collectors, supportable between upper and lower endpiate structures. It comprises at least one rigid clamping device comprising spaced apart transversely disposed elongate clamp members for engaging outer surfaces of the upper and lower endplates respectively along peripheral edges, the clamp members being interposed by vertically disposed support members having a length greater than the height of the stack in a compressed condition thereof. The endpiate structures define docking formations along peripheral edges for engaging the damp members under compression of the stack. The docking formations define spaces between the endpiate structures and the compressing means within which the clamp members are receivable during compression. Upon release of compression, the clamp members remain captively engaged within the docking formations against recoil pressure of the stack.

Claims

1. A clamp assembly for securing a fuel cell stack arrangement in a compressed condition following compression thereof using a compressing means, wherein the fuel cell stack arrangement includes at least an electrode assembly interposed between an upper current collector and a lower current collector, supportable between operatively upper endplate and lower endplate structures, the clamp assembly cornprising:

at least one substantially rigid clamping device, the clamping device comprising spaced apart elongate clamp members for engaging outer surfaces of the upper and lower endplate structures respectively along peripheral edges thereof, the elongate clamp members being interposed by support members disposed substantially in a first direction in which the length of the support members is greater than the height of the fuel cell stack arrangement in a compressed condition thereof; and

wherein the upper and lower endplate structures define docking formations along peripheral edges thereof for engaging the clamp members in a compressed condition of the fuel cell stack arrangement, the clamp members being disposed substantially in a second direction, said second direction being perpendicular to the first direction, the docking formations being configured to define spaces between the endplate structures and the compressing means, the clamp members being receivable within the spaces during compression of the fuel cell stack arrangement and whereupon, in use, release of the compressing means causes the clamp members to become captively engaged within the docking formations against recoil pressure of the fuel cell stack arrangement such that the arrangement is held captive in the compressed condition between the clamp members.

2. A clamp assembly as claimed in claim 1, wherein the fuel cell stack arrangement has a substantially rectangular cross-sectional shape, defining a pair of opposing long sides and a pair of opposing short sides.

3. A clamp assembly as claimed in claim 1, wherein the outer surfaces of the upper and lower endplate structures are substantially planar.

4. A clamp assembly as claimed in claim 2, wherein the endplate structures of the fuel cell stack arrangement are configured such that the long sides thereof are thicker in relation to the short sides thereof.

5. A clamp assembly as claimed in claim 1, wherein the endplate structures are manufactured from any suitable metal having sufficient rigidity and strength to withstand expansion of the fuel cell stack arrangement.

6. A clamp assembly as claimed in claim 1, wherein the clamp assembly is covered with a suitable insulator.

7. A clamp assembly as claimed in claim 1, wherein the clamp assembly comprises two diametrically opposed pairs of rigid clamping devices, each clamping device defining a pair of spaced apart opposing elongate clamp members interposed at remote ends thereof by support members disposed substantially in the first direction and wherein the pairs of clamping devices are adapted to engage the long and the short sides of the fuel stacking structure respectively.

8. A clamp assembly as claimed in claim 7, wherein the clamping devices are in the form of rigid rectangular frame-like structures.

9. A clamp assembly as claimed in claim 8, wherein the pair of frame-like structures for engaging the long sides of the fuel cell stack arrangement have larger dimensions than that of the pair for engaging the short sides of the fuel cell stack arrangement.

10. A clamp assembly as claimed in claim 8, wherein the two pairs of frame-like structures are locatable in nested relation to one another at intersecting corners in an assembled condition of the clamp assembly.

11. A clamp assembly as claimed in claim 1, wherein the docking formations are in the form of step-like recesses.

12. A clamp assembly as claimed in claim 1, wherein corresponding docking formations of the upper and lower endplate structures are configured such that they are locatable in inverted relation to one another in an assembled condition of the fuel cell stack arrangement.

13. A clamp assembly, as claimed in claim 1, wherein one or more apertures are formed in at least one clamp member being adapted to engage the operatively upper endplate structure and one or more corresponding apertures are formed in the outer surface of the upper endplate structure for receiving one or more fastening elements operable to secure the clamp members to the upper endplate structure.

14. A clamp assembly as claimed in claim 3, wherein the fastening elements comprise bolts, screws or the like.

15. A clamp assembly as claimed in claim 13, wherein the fastening elements are receivable through the apertures in threadable engagement therewith.

16. A clamp assembly as claimed in claim 13, wherein the fastening elements are receivable through both the apertures of the clamp members at intersecting corners in a nested condition thereof.

17. A clamp assembly as claimed in claim 16, wherein the apertures of the clamp member adjacent to the upper endplate structure are not provided with threading.

18. A clamp assembly as claimed in claim 1, wherein the compressing means comprises a machine press.

19. A clamp assembly as claimed in claim 1, in which one or more resilient elements are insertable between the clamp members and the upper endplate structure, the resilient elements being operable to facilitate substantially uniform distribution of compression pressure being applied to the fuel cell stack arrangement.

20. A clamp assembly as claimed in claim 19, wherein the resilient element is a spring.

21. A clamp assembly as claimed in claim 1, wherein a delivery mechanism is provided for delivery of fluids and gases between inlet apertures and exhaust apertures defined in the upper endplate structure and respective channels provided therefor in the electrode assembly.

22. A clamp assembly as claimed in claim 21, in which the delivery mechanism includes one or more fluid path formations defined in the upper endplate structure, the one or more fluid path formations extending substantially in the second direction.

23. A clamp assembly as claimed in claim 21, in which one or more drainage apertures are defined in at least one side edge of the upper endplate structure for release of fluids trapped within the delivery mechanism, in which the one or more drainage apertures are in fluid communication with one or more fluid path formations extending substantially in the second direction.

24. A method of assembling a fuel cell stack arrangement, the fuel cell stack arrangement including at least an electrode assembly interposed between an upper current collector and a lower current collector, supportable between operatively upper endplate and lower endplate structures, the method comprising the steps of:

providing a clamp assembly, the assembly comprising at least one clamping device in which the device comprises spaced apart elongate clamp members for engaging outer surfaces of the upper and lower endplate structures respectively along peripheral edges thereof, the elongate clamp members being interposed by support members disposed substantially in a first direction in which the length of the support members is greater than the height of the fuel cell stack arrangement in a compressed condition thereof;

forming one or more docking formations along one or more peripheral edges of the endplate structures in which the docking formations are adapted to engage the clamp members, the clamp members being disposed substantially in a second direction, said second direction being perpendicular to the first direction, in a compressed condition of the fuel cell stack arrangement;

compressing the fuel cell stack arrangement using compressing means;

inserting the clamp members into spaces defined by the docking formations between the endplate structures and the compressing means;

releasing the compressing means, causing the clamp members to become captively engaged within the docking formations against recoil pressure of the fuel cell stack arrangement such that the arrangement is held captive in the compressed condition between the clamp members.

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