Blocking of fluid distribution in PEM fuel cells

Abstract

An end fuel cell assembly 10N has an anode face with a first end (18, Figure 3) having an anode outlet (315, Figure 3) fluidly connected to an anode inlet (325, Figure 3) across an anode face flow fie

Description

TECHNICAL FIELD

[0001] The present disclosure relates to distribution of fluids in a fuel cell stack end plate and in particular to membrane-type fuel cells. BACKGROUND

[0002] A typical fuel cell system includes a fuel cell stack for generating electricity, a hydrogen supply as a fuel to the fuel cell stack, an oxygen (air) supply system for supplying oxygen containing air as an oxidant for the electrochemical reaction and thermal management for removing reaction heat from the fuel cell stack and managing humidity in the stack and water removal. The fuel cell system generates heat and water as well as electricity.

[0003] In fuel cell assemblies, each unit, has an anode, a cathode and an electrolyte (electrolyte membrane). Hydrogen is supplied to the anode and oxygen containing air is supplied to the cathode. By way of a membrane electrode assembly (MEA) the hydrogen and oxygen produce electricity, heat, and water.

[0004] A stack is formed from a number of such fuel cells arranged with separate anode and cathode fluid flow paths. Such a stack is typically in the form of a block comprising numerous individual fuel cell plates held together by end plates at either end of the stack. It is important that the polymeric ion transfer membrane remains hydrated for efficient operation. It is also important that the temperature of the stack is controlled. Thus, coolant may be supplied to the stack for cooling and / or hydration.

[0005] In hydrogen fuel cells, hydrogen gas is supplied to the fuel cell from a source outside the fuel cell. Such fuel cells normally include a proton exchange membrane (PEM) sandwiched between electrodes, together comprising the membrane-electrode assembly (MEA).

[0006] An important consideration in the operation of such fuel cells is the management of water within the system. During operation of a PEM fuel cell, product water from the reaction between hydrogen and oxygen is formed at catalytic sites of the MEA. This water is in one or more phases of liquid, vapor and transitional depending on temperature and pressure when produced, and it must be exhausted from the MEA via the cathode diffusion structure at the same time that oxygen is transported to the cathode face of the MEA. However, it is also important that the ME A remains suitably hydrated to ensure that the internal electrical resistance of the cell remains within tolerable limits. Failure to control the MEA humidification leads to hot spots and potential cell failure and / or poor electrical cell performance. The anode and cathode fluid flow field plates may each include a rigid, electrically conductive, material having fluid flow channels in the surface adjacent the respective diffusion structure for delivery of the reactant gases (for example, hydrogen and oxygen) and removal of the exhaust gases (for example, unused oxygen and water vapor).

[0007] Fuel cell stacks comprise a series of individual fuel cells built up layer by layer into a stack arrangement. Each fuel cell itself may include various layered components, such as a polymer electrolyte membrane, gas diffusion layers, fluid flow plates, and various sealing gaskets for maintaining fluid tightness and providing fluid fuel and oxidant distribution to the active surfaces of the membrane. The fluid inputs and fluid outputs are directed through flow fields and plates at the fuel cell level and through connected manifolds at the stack level. Common ducts are often used to feed oxidant and fuel to the fuel cell in fuel cell assemblies forming a stack.

[0008] In a typical high power fuel cell arrangement, cooling fluid is injected into the anode or cathode face of a fuel cell and disperses. Uneven cooling is suboptimal and impacts uniformity of operation and reduces efficiency.

[0009] High efficiency PEM fuel cells (PEMFC) produce heat and water when operating and the removal or management of same from the fuel cell stack is a factor that impacts efficiency. To keep a temperature within a nominal range while current is flowing, the heat must be reduced or be taken away. It is therefore desiderata to: (1) reduce pooling water in fuel cells forming a stack; (2) reduce uneven cooling of fuel cells within a stack; and, (3) reduce fuel waste in fuel cells forming a stack. DISCLOSURE

[0010] The following description of examples of implementations, reference is made to the accompanying drawings that form a part hereof, and which show, by way of illustration, specific implementations of the present disclosure that may be utilized. Other implementations may be utilized, and structural changes may be made without departing from the scope of the present disclosure.

[0011] Disclosed are aspects of exemplary implementations of reducing uneven cooling or heat removal in fuel cells forming a fuel cell stack.

[0012] Disclosed are aspects of exemplary implementations of conserving fuel in fuel cells forming a fuel cell stack.

[0013] Disclosed are aspects of exemplary implementations of reducing water pooling within a fuel cell end plate.

[0014] Disclosed are aspects of exemplary implementations systems and method of fluid control at the cathode side end plate of a fuel cell stack, the method including placing an end fuel cell assembly having cathode face with a first end having a cathode inlet fluidly connected to a cathode outlet across a cathode face flow field facing the inside of the second end plate of a fuel cell stack, with an outlet stop at the cathode outlet at one the end fuel cell assembly configured to limit fluid flow into a first cathode passage which is fluidly connected to the cathode outlet via the cathode flow field, whereby the outlet stop reduces the volume of fluid entering the cathode flow field. In some instances the cathode outlet stop reduces fluid volume by one of at least 95%, 90%, 80%, 70% and 60%. In some instance the outlet stop has one or more perforations which open gaps in the stop to allow some fluid to pass through.

[0015] Disclosed are aspects of exemplary implementations systems and method of fluid control at the cathode side end plate of a fuel cell stack, the method including placing an end fuel cell assembly having cathode face with a first end having a cathode inlet fluidly connected to a cathode outlet across a cathode face flow field facing the inside of the second end plate of a fuel cell stack, with an outlet stop at the cathode outlet at one the end fuel cell assembly configured to limit fluid flow into a first cathode passage which is fluidly connected to the cathode outlet via the cathode flow field, whereby the outlet stop reduces the volume of fluid entering the cathode flow. Further including an inlet stop on the cathode inlet in fluid communication with the cathode flow field configured to limit fluid flow into the cathode inlet and, wherein, the inlet stop reduces the volume of fluid entering the cathode flow field. In some instance by removing or blocking one or more fluid guides from the cathode inlet fluidly connected to the cathode outlet whereby the amount of water and water vapor entering the cathode flow field is reduced. In some instance, reducing the fluid in the cathode flow field at least one of reduces cooling at the inside of the second endplate and reduces ice formation inside the second end plate.

[0016] Disclosed are aspects of exemplary implementations systems and method of fluid control at the cathode side end plate of a fuel cell stack, the method including a fuel cell assembly having a cathode face with a first end having a cathode inlet fluidly connected to a cathode outlet across a cathode face flow field, an end plate facing the cathode flow field, an outlet stop at the cathode outlet configured to reduce or limit fluid flow into the first cathode passage. In some instances, the outlet stop reduces the volume of fluid entering the cathode flow field. In some instances, the outlet stop has one or more perforations which open gaps in the stop to allow some fluid to pass through. In some instances, reducing the fluid in the cathode flow field at least one of reduces cooling of the inside of the second endplate and reduces ice formation inside the second end plate.

[0017] Disclosed are aspects of exemplary implementations systems and method of fluid control in a fuel cell assembly at an anode side end plate of a fuel cell stack, including placing an end fuel cell assembly having an anode flow field face with a first end having a hydrogen inlet manifold and a hydrogen inlet which is fluidly connected to a first anode fluid passage across the anode face flow field to the hydrogen outlet manifold. The end fuel cell assembly anode flow field face, faces the inside of the first end plate forming an inlet barrier and, the inlet barrier is configured to reduce the volume of fluid entering the anode flow field face. In some instances, the inlet barrier reduces fluid volume by one of at least 95%, 90%, 80%, 70% and 60%. In some instances, the inlet barrier is a portion of the bipolar frame which is configured to one of stop and limit the passage of hydrogen into a first hydrogen passage. In some instances, an outlet barrier blocking the hydrogen outlet slot is added wherein, the outlet barrier reduces the volume of fluid entering the anode flow field face. In some instances, the barrier is a solid region of the bipolar plate. In some instances, the barrier in the anode flow field at least one of reduces cooling of the inside of the first endplate and reduces ice formation inside the first end plate.

[0018] Disclosed are aspects of exemplary implementations systems and method of fluid control in a fuel cell assembly at a cathode side end plate and at an anode side end plate of a fuel cell stack. The cathode side end plate faces a fuel cell assembly with a cathode flow field face and at least one of the cathode inlet and cathode outlet which are fluidly connected to the flow field are blocked. Stops with wall like structure block the inlet or outlet and such wall may have perforations therein to allow some fluid flow and restrict fluid flow. Water fluid guides on may also be eliminated or reduced to reduce or stop water coming into the cathode flow field face. On the anode side of the stack there is a fuel cell assembly configured with an anode flow field face facing the end plate. Portions of the bipolar frame the fuel cell assembly is formed with are normally removed to for a slot or port to allow fluid connection of hydrogen from a hydrogen source to the hydrogen inlet into the anode flow field face. To control hydrogen fluid flow at the anode end plate such an inlet is blocked by a barrier which may include a portion of the bipolar plate. In some instances, the anode side hydrogen outlet is blocked with another barrier. FIGURES

[0019] The present application is further understood when read in conjunction with the appended drawings. For the purpose of illustrating the subject matter, there are shown in the drawings exemplary aspects of the subject matter; however, the presently disclosed subject matter is not limited to the specific methods, devices, and systems disclosed.

[0020] The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.

[0021] Fig. 1 depicts aspects of a side exploded assembly view of a high efficiency fuel cell assembly.

[0022] Fig. 2 depicts aspects of a perspective exploded assembly view from anode side to cathode side of a high efficiency fuel cell assembly.

[0023] Fig. 3 depicts aspects of a top view of the anode side of a frame with anode flow fields of the high efficiency fuel cell assembly in Fig. 1.

[0024] Fig. 4A depicts aspects of a top component view of the cathode side of a frame with cathode flow fields of the high efficiency fuel cell assembly in Fig. 1.

[0025] Fig. 4B depicts aspects of a top view of the cathode side of a frame with cathode components assembled thereon of the high efficiency fuel cell assembly in Fig. 4A.

[0026] Fig. 5 depicts aspects of a top view of the cathode side of a high efficiency fuel cell assembly.

[0027] Fig. 6 depicts aspects of a fuel cell stack formed from a plurality of high efficiency fuel cell assemblies.

[0028] Figs. 7A and 7B show aspects of a cathode inlet cover plate formed to cooperate with a water distribution cover.

[0029] Fig. 7C illustrates limiting or removing water distribution into the “1” fuel cell and first end plate.

[0030] Fig. 8 illustrates fluid control at the 10A fuel cell assembly at the inside of the first end plate.

[0031] Fig. 9 illustrates fluid control at the 10A fuel cell assembly at the inside of the first end plate.

[0032] Fig 10 illustrates fluid control at the hydrogen inlet of the 10N fuel cell assembly at the inside of the second end plate.

[0033] Fig 11 illustrates fluid control at the hydrogen outlet of the 10N fuel cell assembly at the inside of the second end plate.

[0034] All descriptions and callouts in the Figures and all content therein are hereby incorporated by this reference as if fully set forth herein. All citations are hereby incorporated by this reference as if fully set forth herein. Aspects of the disclosure will now be described in detail with reference to the drawings, wherein like reference numbers refer to like elements throughout, unless specified otherwise. FURTHER DISCLOSURE

[0035] The present disclosure may be understood more readily by reference to the following detailed description taken in connection with the accompanying figures and examples, which form a part of this disclosure. It is to be understood that this disclosure is not limited to the specific devices, methods, applications, conditions or parameters described and / or shown herein, and that the terminology used herein is for the purpose of describing particular exemplars by way of example only and is not intended to be limiting of the claimed disclosure.

[0036] Disclosed herein are aspects of methods and systems to provide for at least one of improved cooling and consistent compression of at least one of fluid flow plates, flow assemblies, fuel cells and fuel cells in a stack which improve efficiencies of electrical generation and reduce cost of production.

[0037] By right sizing cathode inlets and outlets to maintain pressure across a flow field and into a gas diffusion layer (GDL) from inlet to outlet on the cathode side of a fuel cell bottlenecks in fluid flow are at least one of eliminated and minimized. The expansion of air and addition of moisture as fluid, containing oxidant, flows through the cathode side of a fuel cell assembly the volume inlet expands by at least a factor of 5 or more times, in some instances it expands by a factor of 50 or more, in some instances it expands by a factor of 100 or more, in some instances it expands by a factor of 200 or more. The instance fuel cell assembly, fuel cells formed from such assembly, and stack formed from a plurality of such fuel cells are a more efficient fuel cell stack by way of minimizing the bottlenecks. More efficient refers to increased power density during operation compared to a traditional fuel cell or stack utilizing traditional fuel cell assembly outlet and inlets.

[0038] Figure 1 is a component overview of a fuel cell assembly and a fuel cell.

[0039] Two fuel cell assemblies 10 and 10’ each having bipolar plates providing fluid flow pathways cooperate when stacked together and compressed as part of a fuel cell stack and together function as a fuel cell 100 in that stack.

[0040] Figure 2 shows aspects of a fuel cell assembly viewed cathode side up. Figures 3-6 show aspects of the anode side of a bipolar plate, assembly of the cathode side of a bipolar plate of this disclosure, and the cathode side of a bipolar plate of this disclosure.

[0041] A membrane electrode assembly (MEA) containing a proton exchange membrane (also known as a polymer electrolyte membrane) is normally a multi-layer interface whereby protons from the anode side of a fuel cell cross the MEA and the stripped off electron travels around the external circuit to generate electricity. On the cathode side oxygen is provided and the hydrogen protons eventually form water with some of the oxygen provided.

[0042] The MEA 12 in a fuel cell assembly (or a fuel cell) traditionally will have some gas diffusion layer or layers between the MEA and bipolar frame 13. Ona first side of the MEA 12A which will be closest to the cathode face flow field 14 of a bipolar frame 13 is a cathode gas diffusion layer (or layers) 15. On the opposite second side of the MEA 12B which will be closest to the anode flow field face 16 of a bipolar frame 13 is an anode gas diffusion layer 17. The bipolar frame 13 has a first end 18 opposite a second end 19. disclosed herein is a bipolar frame configured wherein the anode flow field face 16 is formed as part of the bipolar frame. Disclosed herein is a novel bipolar plate 200 wherein the cathode face has a separate cathode outlet cover 20 attached to the bipolar frame and a separate cathode inlet cover 22 attached to the bipolar frame. Configuring the bipolar frame 13 to affix separate cathode inlet and outlet covers eliminates the waste material caused by using a single cathode frame thus reducing at least one of carbon footprint, cost and manufacturing cost. A separate water distribution cover 30 configured to affix over at least a portion of the cathode inlet cover optionally may be attached. One or more gaskets are added to seal the fuel cell assembly when forming fuel cells within a fuel cell stack. At least a cathode gasket 40 and an anode gasket 42may be present.

[0043] Figure 3 shows aspects of the anode side of a bipolar plate. At the first end 18 is an air inlet 300, a water inlet 310 and a hydrogen outlet to manifold 315 and the flow field to hydrogen outlet slot 316. At the second end 19 is a cathode fluid outlet 320 and a hydrogen inlet manifold 325 and the hydrogen inlet 326. The hydrogen inlet 326 is fluidly connected to the hydrogen inlet manifold 325 and to the anode face flow field 16 of the flow field via a first anode fluid passage 330. The anode face is fluidly connected to a second anode fluid passage 335 that is fluidly connected to the hydrogen outlet to flow field slot 316. The water inlet 310 and air inlet 300 are fluidly connected to the cathode face of the bipolar plate.

[0044] Figure 4A shows aspects of the unassembled cathode side of a bipolar frame 13. The cathode outlet cover 20 attaches to the bipolar frame at its first end 18 aligning with the water inlet, air inlet 300 and hydrogen outlet 315 of the bipolar frame. A first cathode fluid passage 340 is formed at one edge of the cathode inlet cover 22. A separate cathode inlet cover 22 attached to the bipolar frame at its second end 19 aligning the cathode outlet 320 and hydrogen inlet of the bipolar frame. A second cathode fluid passage 345 is formed at one edge of the cathode outlet cover 20. Once the cathode covers are attached the bipolar plate is formed. Those of ordinary skill in the art and the skilled artisan will recognize that traditional bipolar plates utilizing multiple frames affixed together and bipolar plates with a single frame and no covers are within the scope of this disclosure. Optionally a separate water distribution cover is configured to affix over at least a portion of the cathode inlet cover. The air inlet 300 and the water inlet 310 are fluidly connected via a first cathode fluid passage 340 to the cathode face of the bipolar plate. The cathode face is fluidly connected to a second cathode fluid passage 345 which is fluidly connected to the cathode fluid outlet 320.

[0045] Figure 4B shows aspects of the assembled cathode side of a bipolar plate 200B including optional water distribution cover.

[0046] Figure 5 shows aspects of an assembled bipolar plate cathode face up with cathode gas diffusion layer 15 visible. Fluid 500 containing the air, water and water vapor from the air inlet 300 and the water inlet 310 fluidly pass through evenly spaced fluid guides 700 (shown in figures 7A and 7B) to the first cathode fluid passage 340 along the lines of arrow 500 through the cathode face flow field 14 and the cathode gas diffusion layer 15 to the second cathode fluid passage 345 then to the cathode fluid (or exhaust) outlet 320.

[0047] Figure 6 shows an assembly view fuel cell stack 600 formed from a plurality of fuel cell assemblies 10(A-N) a first end plate 602 with an inside 602B and an outside face 602A (not visible) and a second end plate 604 with an inside (not visible) and an outside face 604B. The first end plate 602 is adjacent to the 10N fuel cell assembly at a first end of the stack with the anode face facing the first end plate. The second end plate 604 is adjacent to the 10A fuel cell assembly at a second end of the stack with the cathode face facing the second end plate.

[0048] Figure 7A shows a top view of aspects of a cathode inlet cover 22 having fluid guides 700 therein and Figure 7B shows a blow-up of section “Y” of Figure 7A. The cathode inlet cover has a top surface 701 and is configured to cooperate with the water distribution means to deliver water through an array of fluid guides 700A-700N. Welds or other connectors 702 may be added to affix the cathode inlet cover to the bipolar frame. A series of spacers 705 protrude from the bottom surface 703 of the cathode inlet cover to fluidly connect water flow into the cathode face flow field 14 and cathode gas diffusion layer 15 of a bipolar plate. Fluid guides 700A - 700N may vary in diameter. Figure 7C illustrates the removal of fluid guide 700B’. Some or all fluid guides can be removed from the cathode outlet cover at the 10A fuel cell assembly (see figure 6) to stop or reduce water flow into the cathode face of the fuel cell assembly adjacent to the second end plate 604. The end plates of the stack, each can impact fuel cell operation and efficiency if not properly managed. If the cathode facing second endplate is subjected to normal cathode fluid flow, it may be over cooled and possibly accumulate water therein. If the second end is over heated or over cooled it will change the cooling profile of the stack and an uneven temperature of the fuel cell stack can negatively affect one or more of the operation of the system, the seals, the longevity of the stack, the health of the MEA therein, and the accumulation of ice. By stopping or reducing the water flow through fluid guides which may be removed or have reduced diameter outlets the fluid distribution, water accumulation and cooling profile at the end plate facing cathode side of the 10A fuel cell assembly can be ameliorated.

[0049] Devices, systems and methods disclosed herein will reduce fluid flow across the cathode flow field face 14 of the 10A fuel cell assembly by one of at least 99%, at least 95%, at least 90%, at least 80%, at least 70%, at least 60%, at least 50%, and at least 40%.

[0050] Figure 8 shows the first end 18 and second end 19 of the cathode face of a bipolar plate 13. To limit / reduce or stop fluid flow from the cathode air inlet 300 to the first cathode fluid passage 340 into the cathode face an inlet stop 802 is formed at the inside edge 301 of the air inlet. Stop(s) are continuous walls or may be broken walls with gaps or perforations such as inlet wall gaps 804 whereby a limited flow of air into the first cathode fluid passage may occur. To limit / reduce or stop fluid flow across the cathode face from the first cathode fluid passage 340 to the second fluid passage 345 to the cathode outlet 320 an outlet stop 812 is formed at the inside edge 321 of the cathode outlet. The stop may be a continuous wall, or it may be broken up by perforations or outlet wall gaps 814. The absence or presence of gaps and the placement of stops (802 / 812) may vary from stack design to stack design. Those of ordinary skill in the art and the skilled artisan will recognize that depending on a fuel cell stack’s intended location (stationary or mobile for example) as well as the variations in output and balance of plant, that the amount of cathode fluid blocking via the stop 802 or stop 812 at the cathode face facing end plate will be a spectrum. The disclosure herein provides disclosure on how to use the stop at the outlet or inlet to control such fluid. Controlling the accumulation of water or water vapor on the second face impacts ice formation under certain conditions. The ice formation after shut down will negatively affect the system’s ability to reach an acceptable operating temperature upon heating at start-up and has the potential to add ice to the system. If ice reaches the MEA, it may cause damage such as pin-holes in the MEA which impact the operation and / or output of the fuel cell stack.

[0051] Figure 9 illustrates the use of seals or plugs to block the cathode inlet or outlet. In some instances, the blocking may include or be accomplished with a plug 322 and / or 302 which can be sized to block all or part of the inlet or outlet thereby limiting or closing off flow to the inlet 300 or outlet 320.

[0052] Figure 10 illustrates fluid control at the hydrogen inlet of the 10N fuel cell at the inside of the second end plate. On the bipolar plate 13 the hydrogen inlet and outlets are formed by a removal process leaving openings. In some instance for the 10N fuel cell bipolar plate the hydrogen inlet 325 on the second side 19 is fluidly connected to an inlet barrier 326’. The inlet barrier is positioned to prevent any fluid, including hydrogen, water vapor or moisture from hydrogen inlet 325 from reaching the MEA via the anode flow field face 16 of the 10N fuel cell. The anode outlet flow field slot 316 is not removed or cutout leaving it as an outlet barrier 316’. Separately or together the barriers are configured to limit hydrogen or other fluid from the flow field . In some instance the barrier limits hydrogen from passing to hydrogen outlet slot 316 or from the hydrogen outlet manifold 315 from entering the anode flow field face of the ION fuel cell facing the inside 602B of the first end plate 602. In some instances, other fluids including water vapor may enter the anode flow field face from the MEA or purge, such fluids are also limited or stopped by such barriers. In some instance the barriers are portions of the bipolar plate at the hydrogen inlet slot 326.

[0053] If hydrogen is allowed to freely flow across the second end across the anode flow field face it will cool the first endplate and such cooling may change the heat and cooling profile of the first end plate and the fuel cell stack. Further that hydrogen is wasted and not used by the system as the anode side of the ION fuel cell is not providing fuel to an MEA. Disclosed herein is a system and method configured to limit and reduce hydrogen loss at the anode side of the endplate.. In some instance for the ION fuel cell bipolar plate the hydrogen inlet 326 is a portion or region of the bipolar plate which is not removed during cutting of the inlets and outlets in the plate or permanently blocked after manufacture. Accordingly, the barrier(s) may be plate portions not removed or cutout forming an inlet barrier 326’. In other instances, said barriers may be plugs or seals of a material preferably impermeable to hydrogen gas.

[0054] Devices, systems, and methods, disclosed herein will reduce fluid flow across the anode flow field face 16 of the 10N fuel cell assembly by one of at least 99%, at least, 98%, at least 97%, at least 96%, at least 95%, at least 90%, at least 80%, at least 70%, at least 60%, at least 50%, and at least 40%.

[0055] Moreover, the fluids in the first end plate contain water or water vapor between the first end cover inside 602B and the anode flow field face of the 10N fuel cell assembly ice may also form. If ice crystals form or circulate within the system, they can damage the MEA by perforating or pin holing the surface. Further ice reduces the system temperature and may slow start up of a fuel cell system.

[0056] Those of ordinary skill in the art and the skilled artisan will understand that plugs or seals as described in reference to blocking the cathode inlet and outlet fluid flow at the 10A fuel cell assembly may be used to seal off the hydrogen inlet or outlet.

[0057] In a traditional fuel cell with multiple inlet and outlet ports for at least each of air and hydrogen the blocking of cathode or anode inlets described herein may be utilized to block one or more of the plurality of such inlets and outlets without departing from the scope of the disclosure.

[0058] The systems described throughout this disclosure can be utilized in a variety of applications for providing power generated by fuel cells. In some aspects, the systems disclosed throughout this application can be used in machine handling equipment (MHE), such as a forklift. In some aspects, the systems can be used in an unmanned aerial vehicle (UAV), such as a fixed or multi-rotor drones. In some aspects, the systems disclosed herein can be used in automotive applications, such as in cars, trucks or in aerospace, rail, marine or in stationary power systems. It will be appreciated that the systems can be used in a variety of other applications, and the certain functional and physical parameters, such as component sizes and quantities, may be varied for specific applications and may be dictated by requirements for specific uses. Additional advantages to those described above include being able to fit the systems and related components (such as fuel cannister cylinders) into smaller spaces and to arrange systems and related components.

[0059] The components disclosed herein may utilized known materials that are used in the industry.

[0060] Throughout this specification, words are to be afforded their normal meaning as would be understood by those skilled in the relevant art. However, so as to avoid misunderstanding, the meanings of certain terms will be specifically defined or clarified.

[0061] While the disclosure has been described in connection with the various embodiments of the various figures, it will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this disclosure is not limited to the particular embodiments disclosed, and it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the claims.

[0062] Features of the disclosure that are described above in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, various features of the disclosure that are described in the context of a single embodiment may also be provided separately or in any sub-combination. Finally, while an embodiment may be described as part of a series of steps or part of a more general structure, each said step may also be considered an independent embodiment in itself, combinable with others.

[0063] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. A method of fluid control at the anode side end plate of a fuel cell stack, the method comprising:placing an end fuel cell assembly (ION) having an anode flow field face (16) with a first end having a hydrogen inlet manifold (325) and a hydrogen inlet (326) which is fluidly connected to a first anode fluid passage (330) across the anode face flow field to the hydrogen outlet manifold (315);the end fuel cell assembly anode flow field face, faces the inside of the first end plate (602B);forming a barrier; and,wherein the barrier is configured to reduce the volume of fluid on the anode flow field face.

2. The method of fluid control at the anode side end plate of a fuel cell stack, of claim 1 wherein the barrier is at least one of an inlet barrier (326’) and an outlet barrier (316’).

3. The method of fluid control at the anode side end plate of a fuel cell stack, of claim 1 or 2, the method further comprising the barrier reduces fluid volume by one of at least 99%, 98%, 97%, 96%, 95%, 90%, 80%, 70% and 60%.

4. The method of fluid control at the anode side end plate of a fuel cell stack, of any preceding claim wherein the barrier reduces the loss of unused hydrogen in the end fuel cell assembly by at least one of 99%, 98%, 97%, 96%, 95%, 90%, 80%, 70% and 60%.

5. The method of fluid control at the anode side end plate of a fuel cell stack, of any preceding claim, wherein the barrier is a portion of the bipolar frame which is configured to one of stop and limit the passage of hydrogen into a first hydrogen passage.

6. The method of fluid control at the anode side end plate of a fuel cell stack, of claim 5, wherein the barrier is a solid region of the bipolar plate.

7. An end fuel cell assembly comprising:a fuel cell assembly having an anode face with a first end having an anode outlet (315) fluidly connected to an anode inlet (325) across an anode face flow field (16); an end plate (602) facing the anode flow field;a barrier limiting fluid flow to the anode flow field; and, wherein, the barrier reduces the volume of fluid in the anode flow field.

8. The fuel cell assembly of claim 7 wherein the barrier is at least one of an inlet barrier and an outlet barrier.

9. The fuel cell assembly of claim 7 or 8, wherein reducing the fluid in the anode flow field at least one of reduces cooling of the inside of the first endplate, reduces the loss of unused hydrogen and reduces ice formation inside the first end plate.

10. A method of fluid control at the cathode side end plate of a fuel cell stack, the method comprising:placing an end fuel cell assembly (10A) having a cathode face with a first end having a cathode inlet (300) fluidly connected to a cathode outlet (320) across a cathode face flow field (14) facing the inside of the second end plate (604B) of a fuel cell stack;configuring an outlet stop (802) at the cathode outlet (300) of the end fuel cell assembly to limit fluid flow into a first cathode passage which is fluidly connected to the cathode outlet and the cathode flow field; and,wherein, the outlet stop reduces the volume of fluid entering the cathode flow field.

11. The method of fluid control at the cathode side end plate of a fuel cell stack, of claim 10, the method further comprising the cathode outlet stop reduces fluid volume by one of at least 95%, 90%, 80%, 70% and 60%.

12. The method of fluid control at the cathode side end plate of a fuel cell stack, of claim 11, wherein the outlet stop has one or more perforations (804) which open gaps in the stop to allow some fluid to pass through.

13. The method of fluid control at the cathode side end plate of a fuel cell stack, of claim 11 or 12, the method further comprising an inlet stop on the cathode inlet in fluid communication with the cathode flow field configured to limit fluid flow into the cathode inlet; and,wherein, the inlet stop reduces the volume of fluid entering the cathode flow field.

14. The method of fluid control at the cathode side end plate of a fuel cell stack of any of claims 11 to 13, the method further comprising removing or blocking one or more fluid guides from the cathode inlet fluidly connected to the cathode outlet whereby the amount of water and water vapor entering the cathode flow field is reduced.

15. The method of fluid control at the cathode side end plate of a fuel cell stack of any of claims 11 to 14, wherein reducing the fluid in the cathode flow field at least one of reduces cooling at the inside of the second endplate and reduces ice formation inside the second end plate.

16. An end fuel cell assembly comprising:a fuel cell assembly having cathode face with a first end having a cathode inlet (300) fluidly connected to a cathode outlet (320) across a cathode face flow field (14);an end plate facing the cathode flow field;an outlet stop (802) at the cathode outlet (300) configured to limit fluid flow into the first cathode passage; and,wherein, the outlet stop reduces the volume of fluid entering the cathode flow field.

17. The end fuel cell assembly of claim 16, wherein the outlet stop has one or more perforations (804) which open gaps in the stop to allow some fluid to pass through.

18. The end fuel cell assembly of claim 16 or 17, further comprising removing or blocking one or more fluid guides at the cathode inlet fluidly connected to the cathode outlet whereby the amount of water and water vapor entering the cathode flow field is reduced.

19. The fuel cell assembly of any of claims 16 to 18, wherein reducing the fluid in the cathode flow field at least one of reduces the cooling of the inside of the second endplate and reduces ice formation inside the second end plate.18

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