Pump assembly for a fuel cell system

• US 8,795,926 B2
• Filed: 10/31/2011
• Issued: 08/05/2014
• Est. Priority Date: 08/11/2005
• Status: Active Grant

• Current Assignee: Intelligent Energy Limited (Lb-shell Plc)
• Original Assignee: Intelligent Energy Limited (Lb-shell Plc)
• Inventors: Braithwaite, Daniel, Glassman, Jonathan Louis, Fabian, Tibor, PETERSON, ANDREW PHILLIP GUST, Fisher, Tobin J., RODRIGUEZ, ADAM, Barton, Russell
• Primary Examiner(s): Alejandro, Raymond
• Application Number:
  US13/286,044
• Publication Number:
  US 20120189928A1
• Time in Patent Office: 1,009 Days
• Field of Search: 429/512, 429/513, 429/515, 429/455, 429/443, 429/447, 417/26, 417/27, 417/36, 417/93, 417/118, 417/121, 137/814, 137/833, 137/262
• US Class Current: 429/512
• CPC Class Codes: F04B 43/046 with piezoelectric drive
• CPC Class Codes: F04B 53/10 Valves; Arrangement of valves
• CPC Class Codes: F04B 53/14 Pistons, piston-rods or piston-rod connections
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2250/30 Fuel cells in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04201 Reactant storage and supply, e.g. means for feeding, pipes
• CPC Class Codes: H01M 8/04208 Cartridges, cryogenic media or cryogenic reservoirs
• CPC Class Codes: H01M 8/04216 characterised by the choice for a specific material, e.g. carbon, hydride, absorbent
• CPC Class Codes: H01M 8/0606 with means for production of gaseous reactants
• CPC Class Codes: H01M 8/065 by dissolution of metals or alloys; by dehydriding metallic substances
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A pump assembly including a first subassembly and a second subassembly. The first subassembly includes a fluid conduit; an inlet fluidly coupled to the liquid reactant dispenser and the fluid conduit; an outlet fluidly coupled to a reaction chamber and the fluid conduit; and a diaphragm, defining a portion of the fluid conduit, that flexes to pump the liquid reactant from the inlet to the outlet. The diaphragm preferably includes an actuation point coupled to the diaphragm, wherein the liquid reactant is substantially contained within the first subassembly during pumping. The second subassembly is couplable to the first subassembly, and is fluidly isolated from the liquid reactant. The second subassembly includes an actuator that couples to the actuation point, wherein operation of the actuator causes pumping action.

Claims

1. A pump assembly for a fuel cell system, the fuel cell system including a fuel cartridge and a fuel cell assembly, the fuel cartridge including a liquid reactant dispenser containing a liquid reactant and a reaction chamber distinct from the liquid reactant dispenser, the fuel cell assembly including a fuel cell, the pump assembly comprising:

a first subassembly including;

a fluid conduit, an inlet fluidly coupled to the liquid reactant dispenser and the fluid conduit, an outlet fluidly coupled to the reaction chamber and the fluid conduit, a diaphragm that defines a portion of the fluid conduit and that flexes to pump the liquid reactant from the inlet to the outlet, and an actuation point coupled to the diaphragm;

wherein the liquid reactant is substantially contained within the first subassembly during pumping; and

a second subassembly, couplable to the first subassembly and fluidly isolated from the liquid reactant, the second subassembly including an actuator that couples to the actuation point, wherein operation of the actuator causes diaphragm flexion.

2. The pump assembly of claim 1, wherein the first subassembly further includes an auxiliary component that couples the actuation point to the diaphragm.

3. The pump assembly of claim 2, wherein the auxiliary component is a reciprocating rod, disposed between the exterior of the first subassembly and the diaphragm, with a diaphragm end and a distal end, wherein the distal end is the actuation point, wherein the rod transfers a force from the actuator to the diaphragm.

4. The pump assembly of claim 1, wherein the actuation point is a portion of the diaphragm.

5. The pump assembly of claim 1, wherein the diaphragm flexes between two states to pump the liquid reactant, the two states including:

a flexed state that creates a positive pressure within the fluid conduit and facilitates liquid reactant egress from the outlet; and

an unflexed state that creates a negative pressure within the fluid conduit and facilitates liquid reactant ingress from the inlet.

6. The pump assembly of claim 5, wherein the fluid conduit is a pumping chamber, wherein the diaphragm defines a wall of the pumping chamber proximal to the first subassembly exterior, wherein the inlet and outlet include a one-way inlet valve and outlet valve, respectively.

7. The pump assembly of claim 5, wherein the spring force of the diaphragm transitions the diaphragm from the flexed to the unflexed state.

8. The pump assembly of claim 5, wherein the second subassembly further includes a translating member coupled to the actuator, wherein the actuator reciprocates the translating member between two states:

a retracted mode wherein the translating member does not transfer substantial force from the actuator to the diaphragm, wherein the diaphragm is in the unflexed state; and

an extended mode wherein the translating member transfers substantial force from the actuator to the actuation point, wherein the diaphragm is in the flexed state.

9. The pump assembly of claim 8, wherein the translating member contacts the actuation point in retracted mode.

10. The pump assembly of claim 9, wherein the translating member is a pump plunger.

11. The pump assembly of claim 8, wherein the actuator is a mechanical actuator.

12. The pump assembly of claim 11, wherein the actuator is a screw actuator, wherein the translating member is the screw.

13. The pump assembly of claim 1, wherein the pump assembly further includes a coupling mechanism that removably couples the first subassembly to the second subassembly.

14. The pump assembly of claim 13, wherein the coupling mechanism is a tongue and groove couple, wherein the first subassembly includes a tongue and the second subassembly includes a groove.

15. The pump assembly of claim 1, wherein the fluid conduit comprises a prismatic pumping chamber, the diaphragm forming the chamber wall most proximal to the first subassembly exterior, the inlet being located on a wall adjacent to the diaphragm, and the outlet being located on a wall opposing the inlet.

16. The pump assembly of claim 1, wherein the fluid conduit comprises a substantially flexible tube, the diaphragm being a longitudinal portion of the tube and first and second ends of the tube forming the inlet and outlet, respectively.

17. The pump assembly of claim 1, wherein the diaphragm flexes between two states to pump the liquid reactant, such that:

flexion of the diaphragm toward the exterior of the first subassembly creates a negative pressure within the fluid conduit that facilitates liquid reactant liquid reactant ingress from the inlet; and

relaxation of the diaphragm toward the interior of the first subassembly creates a positive pressure within the fluid conduit and facilitates liquid reactant egress from the outlet.

18. The pump assembly of claim 1, wherein the diaphragm comprises silicone rubber, polyethylene, polyvinyl chloride, polyether ether ketone, polytetrafluoroethylene, aluminum, copper, cobalt, nitinol, magnetite, or a combination thereof

19. The pump assembly of claim 3, wherein the rod is mechanically coupled to the diaphragm and the second subassembly.

20. The pump assembly of claim 3, wherein the second subassembly linearly actuates the rod to extend and retract.

21. The pump assembly of claim 3, wherein the rod is magnetically coupled to the diaphragm and the second subassembly, wherein a change in a magnetic field of the second subassembly results in a linear translation against the diaphragm, flexing the diaphragm.

22. The pump assembly of claim 2, wherein the fluid conduit comprises a substantially flexible tube, the diaphragm being a longitudinal portion of the tube and first and second ends of the tube forming the inlet and outlet, respectively, and the auxiliary component is a rotor comprising one or more rollers protruding radially from the rotor.

23. The pump assembly of claim 2, wherein the fluid conduit comprises a substantially flexible tube, the diaphragm being a longitudinal portion of the tube and first and second ends of the tube forming the inlet and outlet, respectively, and the auxiliary component is a concave groove disposed on the diaphragm most interior to the first subassembly, such that the auxiliary component is concave toward the center of the exterior of the first subassembly and the diaphragm is disposed between the auxiliary component and the exterior of the first subassembly.

24. The pump assembly of claim 1, wherein the actuator comprises a shape memory alloy.

25. The pump assembly of claim 1, wherein actuator comprises a rotatable cam, said cam having an axis of rotation offset from center.

26. The pump assembly of claim 1, wherein actuator comprises a piezoelectric driver.

27. A fuel cartridge for a fuel cell system, the fuel cell system including a fuel cell arrangement and a fuel cartridge, wherein the fuel cell arrangement includes a fuel cell and a connector sub-assembly including an actuator, wherein the fuel cartridge comprises:

a liquid reactant dispenser;

a reaction chamber; and

a cartridge sub-assembly, connectable to the fuel cell sub-assembly, the cartridge sub-assembly comprising;

an inlet fluidly coupled to the liquid reactant dispenser;

an outlet fluidly coupled to the reaction chamber; and

a flexible diaphragm in fluid communication with the inlet and outlet; and

wherein the actuator causes the diaphragm to reciprocate and pump a liquid reactant from the liquid reactant dispenser to the reaction chamber, wherein the liquid reactant reacts within the reaction chamber to produce a fuel usable by the fuel cell, wherein the liquid reactant is substantially contained within the fuel cartridge during the pumping.

28. The fuel cartridge of claim 27, wherein the inlet and outlet include a one-way inlet valve and a one-way outlet valve, respectively, wherein the cartridge sub-assembly further includes a pumping chamber fluidly coupled to the inlet valve and outlet valve, wherein the diaphragm defines a wall of the pumping chamber, wherein the diaphragm reciprocates between two states:

an unflexed state that decreases the pressure within the pumping chamber to open the inlet valve and close the outlet valve, allowing liquid reactant ingress into the pumping chamber; and

a flexed state that increases the pressure within the pumping chamber that to open the outlet valve and close the inlet valve, allowing liquid reactant egress from the pumping chamber.

29. The fuel cartridge of claim 28, wherein the diaphragm is a substantially flat sheet of rubber.

30. The fuel cartridge of claim 27, wherein the liquid reactant is an acid, and the reaction chamber includes a substantially solid sodium borohydride composition.

31. A fuel cartridge for a fuel cell system, the fuel cell system including a fuel cell arrangement and a fuel cartridge, wherein the fuel cell arrangement includes a fuel cell and a connector sub-assembly connectable to the fuel cartridge connector sub-assembly and comprising an actuator, wherein the fuel cartridge comprises:

a liquid reactant dispenser including a liquid reactant;

a reaction chamber; and

a connector sub-assembly comprising;

a pumping chamber;

an inlet, including an one-way inlet valve, fluidly coupled to the liquid reactant dispenser and the pumping chamber;

an outlet, including an one-way outlet valve, fluidly coupled to the reaction chamber and the pumping chamber; and

a diaphragm, defining a portion of the pumping chamber, that reciprocates between two states to pump the liquid reactant from the liquid reactant dispenser to the reaction chamber, wherein the actuator induces the diaphragm reciprocation, the two states including;

an unflexed state that decreases the pressure within the pumping chamber to open the inlet valve and close the outlet valve, allowing liquid reactant ingress into the pumping chamber; and

a flexed state that increases the pressure within the pumping chamber that to open the outlet valve and close the inlet valve, allowing liquid reactant egress from the pumping chamber;

wherein the liquid reactant is substantially contained within the fuel cartridge during the pumping.