Fuel cell stack and method of manufacturing same

Abstract

The fuel cell system includes a first non-conductive sheet portion having a coolant flow layer within an opening therein, a first non-stamped flat metal separator on a first side of the coolant flow layer, and a second non-stamped flat metal separator on a second side of the coolant flow layer opposite the first separator. A membrane is received in the opening in the second non-conductive sheet portion. Gas diffusion layers are located on either side of the membrane. The gas diffusion layers have channels opening into the first non-stamped flat metal separator or the second non-stamped flat metal separator to allow for the flow of oxidant and / or fuel.

Description

[Technical field]

[0001] The present invention relates generally to methods and systems for manufacturing fuel cell stacks, and more particularly to systems and methods for manufacturing fuel cell stacks that minimize damage to the fuel cell stack system and increase the efficiency of the manufacturing process. [Background technology]

[0002] Fuel cells can be classified according to the type of electrolyte (e.g., solid oxide, molten carbonate, alkaline, phosphoric acid, or solid polymer) used to electrochemically convert fuel and oxidant into electricity and heat and accommodate ion movement during operation. Furthermore, fuel cell assemblies can be used in many environments (e.g., from automotive to aerospace, industrial to residential) for multiple applications.

[0003] Proton Exchange Membrane (PEM) fuel cells convert the chemical energy of a fuel, such as hydrogen, and an oxidant, such as air, directly into electrical energy. PEMs are commercially available polymer electrolytes that allow the passage of protons (i.e., H+ ions) from the "anode" side of the fuel cell to the "cathode" side of the fuel cell while preventing the passage of reactant fluids (e.g., hydrogen and air gases). A membrane electrode assembly (MEA) is positioned between two conductive plates, each of which has channels that direct fuel to the anode side of the PEM and oxidant to the cathode side.

[0004] To increase the overall power output of the assembly, two or more fuel cells can be connected together. Generally, the cells are connected in series, with one side of the plate acting as the anode plate of one cell, and the other side of the plate being the cathode plate of the adjacent cell. These are generally referred to as bipolar plates (hereinafter "BPP"). Alternatively, the anode plate of one cell is electrically connected to the separate cathode plate of the adjacent cell. Generally, these two plates are connected back-to-back, and are often bonded together (e.g., bonded by adhesive, welding, or polymer). This bonded pair becomes one, also commonly referred to as a bipolar plate, since the anode plate and cathode plate represent electrically the positive and negative electrodes. Such a series of connected multiple fuel cells is called a fuel cell stack. The stack typically includes a means for directing fuel and oxidant to the flow field channels of the anode and cathode, respectively. The stack typically includes a means for directing a coolant fluid to the internal channels within the stack to absorb heat generated by the exothermic reaction of hydrogen and oxygen in the fuel cells. The stack generally includes means for exhausting excess fuel and oxidant gases, as well as product water.

[0005] The stack also includes end plates, insulators, membrane electrode assemblies, gaskets, separator plates, electrical connectors and collector plates integrated together to form a working stack designed to generate electricity. Different plates can be abutted against each other and connected to each other to facilitate the performance of specific functions.

[0006] Currently, fuel cell manufacturing and assembly is a manual process. Each individual fuel cell component (e.g., bipolar fuel cell plate, membrane electrode assembly, end plate, gas diffusion layer) requires an individual manufacturing process followed by assembly of the various components together. Such assembly is a manual intensive and precise process in which any number of accidents or defects can cause damage to a portion of the fuel cell stack (e.g., fuel cell plate or other component), resulting in the fuel cell stack not being of suitable quality and having to be scrapped. For example, bending of a fuel cell plate of a fuel cell stack can cause a short circuit such that the entire fuel cell stack cannot be utilized.

[0007] Furthermore, the manual nature of fuel cell stack machining and assembly is inefficient compared to other manufacturing processes in related technologies, such as automotive or battery manufacturing, which may be more automated.

[0008] Therefore, there is a need for improved fuel cell stacks and improved methods of manufacturing fuel cells that increase efficiency and minimize damage to fuel cell components in an assembled fuel cell system. Summary of the Invention

[0009] In a first aspect, the present invention provides a first non-conductive sheet portion having a coolant flow layer within an opening therein, a first non-stamped flat metal separator on a first side of the coolant flow layer, and a second non-stamped flat metal separator on a second side of the coolant flow layer opposite the first separator. A membrane electrode assembly is received in the opening in the second non-conductive sheet portion. Gas diffusion layers are located on either side of the membrane electrode assembly. The gas diffusion layers have channels opening into the first non-stamped flat metal separator or the second non-stamped flat metal separator to allow for the flow of oxidant and / or fuel.

[0010] The invention in a second aspect is a fuel cell subassembly for use in forming a fuel cell stack including a non-conductive sheet and a plurality of fuel cell component locations linearly spaced apart on the sheet. A first of the plurality of fuel cell component locations includes a first sheet portion of the sheet having a first opening, a metal separator on a first side of the sheet covering the opening, a coolant flow layer received in the first opening at the first location, and a second separator on a second side of the sheet covering the first opening. A second of the plurality of fuel cell component locations includes a membrane electrode assembly received in a second opening of the sheet. A first gas diffusion layer is located on a first side of the second opening and a second gas diffusion layer is located on a second side of the opening.

[0011] In a third aspect, the present invention provides a method for use in manufacturing a fuel cell system, comprising forming a plurality of openings in a non-conductive sheet. The openings are linearly spaced on the sheet. A metal separator is disposed on a first side of the sheet covering a first opening in a first portion of the sheet. A coolant flow layer is located within the first opening. A second separator is disposed on a second side of the sheet covering the first opening. A membrane electrode assembly is disposed in a second opening in a second sheet portion of the sheet. A first gas diffusion layer is located on the first side of the second opening and a second gas diffusion layer is located on the second side of the second opening.

[0012] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The foregoing and other features and advantages of this invention will be readily understood from the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram of a fuel cell system according to the present invention.

[0014] [Diagram 2] FIG. 2 is a perspective view of a portion of a fuel cell in the fuel cell system of FIG.

[0015] [Diagram 3] FIG. 3 is an exploded view of a fuel cell of the system of FIG. 2.

[0016] [Figure 4] FIG. 4 is an enlarged schematic diagram of a portion of the fuel cell of the system of FIG. 3.

[0017] [Diagram 5] FIG. 2 is a schematic diagram of the manufacture of the system of FIG. 1 showing its components on a web.

[0018] [Figure 6] FIG. 6 is a side view of cutting the web of FIG. 5 to form channels in the web.

[0019] [Figure 7] FIG. 7 is a side view of the connection of a separator to the bottom of the web of FIG. 6 to form a cavity for receiving a coolant layer.

[0020] [Figure 8] FIG. 8 is a side view of a coolant layer received within the cavity of FIG. 7.

[0021] [Figure 9] FIG. 9 is a side view of the membrane electrode assembly attached to the top and bottom of the web of FIG. 8.

[0022] [Figure 10] FIG. 10 is a side view of the connection of a second separator to the top of the web above the coolant layer of FIG.

[0023] [Figure 11] FIG. 11 is a side view of the molding of the seal on the system of FIG.

[0024] [Figure 12] 11 is a top schematic view of the web of FIG. 10 receiving the input of multiple other webs.

[0025] [Figure 13] FIG. 4 is a perspective view of a portion of the gas diffusion layer of FIG. 3. Detailed Description of the Invention

[0026] Various exemplary embodiments according to the present invention will now be described in detail with reference to the drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures are not shown in detail to avoid unnecessarily obscuring the present invention.

[0027] Thus, all embodiments described below are exemplary embodiments provided to enable one skilled in the art to make or use embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined by the claims. As used herein, the term "exemplary" or "exemplary" means "serving as an example, instance, or illustration." An embodiment described herein as "exemplary" or "exemplary" should not necessarily be construed as preferred or advantageous over other embodiments. Furthermore, as used herein, the terms "upper," "lower," "left," "rear," "right," "front," "vertical," "horizontal," and their derivatives refer to the present invention as shown in FIG. 1.

[0028] Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the accompanying drawings, and described in the following specification, are merely exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0029] According to the principles of the present invention, a method for manufacturing a fuel cell system and a fuel cell stack is provided. In the example shown in FIG. 1, a fuel cell system 101 is functionally generating electricity with all its parts, typically referred to as an assembled or completed system, including a fuel cell stack 20 and an energy storage device 30. The fuel cell is supplied with fuel 13, e.g., hydrogen, via a fuel inlet 17. Excess fuel 18 may be exhausted from the fuel cell via a purge valve 90 and may be diluted by a fan 40. In one example, the fuel cell stack 20 may have an open cathode architecture of a PEM fuel cell, and a combination of oxidant and coolant, e.g., air, may enter through an inlet air filter 10 coupled to an inlet 5 of the fuel cell stack 20. Excess coolant / oxidant and heat are exhausted from the fuel cell cathodes of the fuel cell stack 20 through an outlet 11 to a fan 40, and the coolant / oxidant and / or excess fuel may be exhausted to a waste outlet 41, such as the ambient atmosphere. The fuel and coolant / oxidant may be supplied by a fuel source 7 and an oxidant source 9 (e.g., air), respectively, as well as other components of the balance of plant, which may include compressors, pumps, valves, fans, electrical connections and sensors.

[0030] 2 shows a schematic exploded view of an inner subassembly 100 of the fuel cell stack 20 of FIG. 1, including a cathode plate separator 110 at an outer end 115 and a plate separator seal 120 on the inner side. A membrane electrode assembly (MEA) 130 is located between the seal 120 and a second plate separator seal 150. An anode plate separator 160 is at a second end 165 of the subassembly 100.

[0031] The MEA 130 includes a membrane 140 (e.g., an ion-conducting membrane) between a cathode catalyst layer 125 and an anode catalyst layer 135. A cathode gas diffusion layer (GDL) 122 is located between the cathode catalyst layer 125 and a plate separator 110 of the membrane electrode assembly. An anode gas diffusion layer 145 is located between the anode catalyst layer 135 and a plate separator 160 of the membrane electrode assembly. The seals 120 and 150 may be received in channels inside the plate separators 110 and 160, respectively. In another example, such seals may be injection molded around the MEA (e.g., MEA 130) or another fuel cell component, as described below.

[0032] FIG. 3 shows the internal subassembly 100 in an exploded view similar to FIG. 2, except that the seals (i.e., seal 120 and seal 150) are different as described below, and the cathode plate separator 110 is shown below the anode plate separator 160 rather than above the anode plate separator, with such depiction indicating that the elements may be repeated for a complete fuel cell stack (e.g., fuel cell stack 20).

[0033] The gas diffusion layer 145 may be received in an opening 146 in a gas diffusion layer seal 149, which may be formed of a non-conductive material such as an elastomer. The coolant frame 170 may have an opening 172 for receiving a conductive porous coolant layer 174 (e.g., a screen or mesh or a conductive felt). The gas diffusion layers 122 are depicted at both ends of the subassembly to show the repeating nature of the elements, but may be received in openings 124 in the seal 126 with the seal 126 and diffusion layer 122 arranged in a manner similar to that depicted for the gas diffusion layer 145 and seal 149.

[0034] 4 shows an expanded schematic view of a subassembly 100 including a coolant layer 174 of plate separator 160 housed in a coolant frame (FIG. 3) and a plate separator 110 arranged similarly to FIG. 3. The membrane electrode assembly 130 is located between the gas diffusion layer 122 and the gas diffusion fusion layer 145.

[0035] The gas diffusion layer 122 and the gas diffusion fusion layer 145 may include channels 200 for receiving fuel and oxidant flow therein, with the channels bounded by ribs 208 (FIG. 13). The gas diffusion layers (e.g., gas diffusion layer 122, gas diffusion layer 145) may be formed of carbon fiber and may be porous to allow fuel and oxidant flow. The gas diffusion layers (e.g., gas diffusion layer 122, gas diffusion layer 145) may also be formed from other electrically conductive porous substrates, such as metal foams. Additionally, the gas diffusion layers may be configured to be sufficiently stiff to support compressive loads and electrically conductive to minimize bulk and contact resistance.

[0036] The gas diffusion layer 122 can include fuel channels 205 (of channels 200) for receiving hydrogen, and the gas diffusion layer 145 can include oxidant channels 210 (of channels 200) for receiving oxygen, which can generate electricity via reactions at the membrane electrode assembly 130. The presence of such channels (i.e., channels 200) in the gas diffusion layer (e.g., gas diffusion layer 122 and gas diffusion fusion layer 145) instead of in the plate separator (e.g., plate separator 110 and plate separator 160) allows the separator to be made of a thin metal foil, such as aluminum, as opposed to prior art plate separators made of stamped stainless steel. More specifically, the metal used in such separator plates can be thinner than previous stamped separators, not stamped, and made of aluminum instead of stainless steel, due to the presence in the gas diffusion layer of the flow paths for fuel and oxidant flow where such channels are formed in prior art metal separator plates. The separators (e.g., plate separator 110 and plate separator 160) may be further treated or coated with a coating (e.g., metal oxide or gold coating) to inhibit corrosion when exposed to oxidizers and / or fuels, for example, when such separators are formed of aluminum. The flat, non-stamped nature of the separators can minimize coating problems that arise when coated metal is stamped or when coatings are applied to stamped metal, and flat separators have fewer defects and minimize or eliminate damage from stamping. The areas where the plates are stamped in such prior art stamped separators are undesirable as they are known nucleation points for corrosion. The described non-stamped separators (e.g., plate separator 110 and plate separator 160) can be further formed of, for example, aluminum, stainless steel, titanium, nickel, or graphite composites.

[0037] Additionally, the porosity of the channel ribs 208 separating the channels 200 of the gas diffusion layers (e.g., gas diffusion layer 122 and gas diffusion weld layer 145) does not restrict diffusion therethrough, thereby resulting in a reduction in reactant transport resistance typically observed in conventional flow fields with solid ribs. While reduced reactant transport resistance is typically observed in porous flow fields, the present invention introduces a uniform convective path for water removal that the channel flow field provides (e.g., within channels 200).

[0038] The fuel cell subassembly 100 can be manufactured using methods based on the use of webs or plastic sheets that connect the components of a fuel cell stack (e.g., fuel cell stack 20) ​​during its manufacture. Such web-based manufacturing can be more efficient than prior art manufacturing methods, including more manual methods.

[0039] In one example of such a method for manufacturing a fuel cell stack, shown in Figure 5, a web or plastic sheet 300 can have a number of fuel cell components (e.g., gas diffusion layers, separators, membrane electrode assemblies) formed thereon or attached thereto. Such components may be formed on the web as it moves from a particular manufacturing location to another location where different processes are performed at such different location. The components can then be assembled to form a fuel cell stack (e.g., fuel cell stack 20).

[0040] 6 shows a side view of web 300 including forming various features on web 300, for example, by cutting web 300 via cutting punch 400 and cutting die 410. For example, cutting die 400 can cut channels 310 (FIG. 5) in web 300 and dive through conduits 320 (FIG. 5) to allow for hydrogen and / or oxidant flow in a direction parallel to or perpendicular to the plane or longitudinal dimension of web 300. Additionally, openings, such as opening 172 in frame 170, can be cut to accommodate fuel cell components.

[0041] 7, separator 160 may be attached to bottom 301 of web 300 utilizing printed adhesive 162 or another such attachment mechanism below opening 172. A platen 420 and clamps 430 can hold top 305 of web 300, while an alignment fixture 440 can hold separator 160 during such attachment process.

[0042] As shown in FIG. 5, the separators (e.g., separator 110 and separator 160) may be formed separately or cut from a roll before being connected to web 300 in the illustrated process. Such separate creation may include creation of dive through conduits 321 and other features to allow functional engagement (e.g., fluid flow) with other components of the fuel cell stack. Additionally, the separators may be treated or coated (e.g., metal oxide, gold coating, or other corrosion resistant thin films) to inhibit corrosion due to exposure of the separator to oxidants, fuel, and water present in the fuel cell environment. Manufacturing lines for creating such separators may be aligned perpendicular to the longitudinal dimension of web 300 to facilitate transfer of finished separators to web 300.

[0043] 8, a coolant layer 174 may be contained in the openings 172 of the web 300. Such a coolant layer may be formed separately (e.g., via a manufacturing line aligned perpendicular to the longitudinal dimension of the web 300) or may be deposited in the openings 172 via an automated or manual placement mechanism (e.g., a pick-and-place robot). The coolant layer 174 may be a conductive porous material such as aluminum mesh or porous carbon fiber that is utilized to recirculate a flow of coolant to maintain a proper temperature of the assembly 100 and the fuel cell stack (e.g., fuel cell stack 20) ​​of which the assembly is a part.

[0044] 9, the gas diffusion layer 122 may be attached to the top 305 of the web 300, and the gas diffusion layer 145 previously attached to the membrane electrode assembly 130 may be attached to the bottom 301 of the web 300 with the opening 132 therebetween. The membrane electrode assembly 130 may be received in such opening with the gas diffusion layer attached to the web 300.

[0045] For example, the anode and cathode GDLs (e.g., gas diffusion layer 122, gas diffusion layer 145) can be coated with corresponding catalyst layers (e.g., cathode side catalyst layer 125 and anode side catalyst layer 135), and then the membrane (e.g., membrane 140) can be laminated onto the anode GDL (e.g., gas diffusion layer 145). A membrane electrode assembly (e.g., MEA 130) can be formed by hot pressing the aligned anode and cathode portions to attach the membrane electrode assembly to the web 300. Heated platens 450, 460 held by clamps 470 can hold the gas diffusion layers (gas diffusion layer 122, gas diffusion layer 145) and the membrane electrode assembly 130 while bonding (e.g., via a heat-sensitive adhesive or the mating portions of the opposing gas diffusion layers to each other) to the web 300 occurs.

[0046] As mentioned above, the gas diffusion layer (gas diffusion layer 122, gas diffusion layer 145) can include channels 200 and can be formed to include such channels in a manufacturing line perpendicular to the direction of the web 300 so that the gas diffusion layer can be easily attached to a membrane electrode assembly (e.g., membrane electrode assembly 130) and moved to the web 300 from such a vertical manufacturing line. Such grooves can be formed in the gas diffusion layer, for example, with a groove cutting tool. Alternatively, material may be added during the carbon fiber manufacturing process.

[0047] 10, the separator 110 may be attached to the top 305 of the web 300 utilizing a printed adhesive 162 or another such attachment mechanism, above an opening (e.g., opening 172) in the web 300. A platen 480 and clamps 490 can hold the separator 160 and bottom 301 of the web 300, while an alignment fixture 475 and clamps 495 can hold the plate 110 during such attachment process. The attachment of the separator 110 to the web 300 and separator 160 forms a first subassembly 600.

[0048] The seals can be positioned at one or more locations along the web 300, as shown in Figure 11. For example, the seals 120 and 150 (Figure 2) can be formed by injection molding on either side of the web 300 around the gas diffusion layers and membrane electrode assemblies (e.g., gas diffusion layer 145, gas diffusion layer 122, membrane electrode assembly 130) using mold 500 and mold 505. The formation of the seals (e.g., seals 120 and 150) on the gas diffusion layers and membrane electrode assemblies forms a second subassembly 610.

[0049] As described above, various fuel cell components may be formed on and / or connected to the web 300, including the first subassembly 600 and the second subassembly 610. These subassemblies may be continuously repeated on the web 300 such that the web 300 may be utilized as a base for an efficient manufacturing process. For example, the web 300 may be cut perpendicular to its longitudinal dimension, and multiple instances of such depicted subassemblies may be separated from one another and assembled into a fuel cell stack (fuel cell stack 20). Alternatively, the web 300 may remain partially or completely intact in the longitudinal direction after such assembly of a fuel cell stack.

[0050] 12 shows a schematic example of a manufacturing process using the steps described above in forming subassemblies (e.g., first subassembly 600 and second subassembly 610), in which a metal foil roll 700, a mesh roll 710 (e.g., to form coolant layer 174), a plastic (e.g., PET) sheet roll 720, and a second foil metal roll 730 (e.g., to form separators 110 and 160) can be utilized as inputs to the process. Additionally, a roll of gas diffusion layer 740 (e.g., to form gas diffusion layer 145, gas diffusion layer 122) can also be utilized, one of which can include a membrane electrode assembly attached thereto (e.g., to form example membrane electrode assembly 130). Thus, input rolls (e.g., metal foil roll 700, mesh roll 710, second foil metal roll 730, PET roll 720, roll of gas diffusion layer 740) may be utilized on a manufacturing line as described above such that multiple subassemblies (e.g., first subassembly 600 and second subassembly 610) may be output on a continuous roll 760 before being cut to separate particular fuel cell components or subassemblies (e.g., examples of subassembly 600 and subassembly 610) to form fuel cell stacks as described above. In some examples, it may not be necessary to cut the continuous web (e.g., web 300) after output of such subassemblies, as the web may be fully incorporated into the fuel cell (fuel cell stack 20).

[0051] While several embodiments of the present invention have been described and illustrated herein, alternative embodiments may be effected by those skilled in the art to accomplish the same objectives, and it is therefore intended by the appended claims to cover all such alternative embodiments as fall within the true spirit and scope of the invention.

Claims

1. 1. A fuel cell system comprising: a first non-conductive sheet portion having a coolant flow layer within the first opening; a first unstamped flat metal separator on a first side of the coolant flow layer; a second non-stamped flat metal separator on a second side of the coolant flow layer opposite the first separator; a membrane received within the opening in the second non-conductive sheet portion; gas diffusion layers on either side of the membrane, the gas diffusion layers having channels opening into the first unstamped flat metal separator or the second unstamped flat metal separator to allow oxidant and / or fuel to flow; A fuel cell system comprising:

2. 10. The system of claim 1, wherein the first metal separator and the second metal separator comprise metal foil plates coated to inhibit corrosion by the fuel and / or the oxidant and / or coolant and / or contaminants and / or reaction products.

3. 10. The system of claim 1, wherein the gas diffusion layer is porous to a fuel and / or an oxidant and allows flow therethrough for generating electricity at the membrane.

4. The system of claim 1 , wherein the first metal separator and the second metal separator are bonded to the first non-conductive sheet portion.

5. The system of claim 1 , wherein the gas diffusion layers are bonded to the second non-conductive sheet portions on both sides of the membrane.

6. 10. The system of claim 1, wherein the coolant layer comprises an electrically conductive porous material contained in coolant openings in the non-conductive sheet portion to enable flow of coolant therethrough to control a temperature of the system.

7. 1. A fuel cell subassembly for use in forming a fuel cell stack, comprising: A non-conductive sheet; a plurality of linearly spaced fuel cell component locations on said sheet; a first location of the plurality of fuel cell component locations, a first sheet portion of the sheet having a first opening and a metal separator on a first side of the sheet covering the opening; a coolant flow layer received in the first opening at the first location; a second metal separator on a second side of the sheet covering the first opening; and a second location of the plurality of fuel cell component locations, a membrane received in a second opening in the sheet; a second location including a first gas diffusion layer located on a first side of the second opening and a second gas diffusion layer located on a second side of the second opening; a fuel cell subassembly comprising:

8. 8. The subassembly of claim 7, wherein the first separator and the second separator are connected to the sheet at the first location and the first gas diffusion layer and the second gas diffusion layer are connected to the sheet at the second location.

9. 8. The subassembly of claim 7, wherein the first metal separator and the second metal separator comprise metal foil plates coated to inhibit corrosion by fuel and / or oxidant and / or coolant and / or contaminants and / or reaction products.

10. The subassembly of claim 7 , wherein the first metal separator and the second metal separator comprise flat, unstamped metal plates.

11. The system of claim 7 , wherein the gas diffusion layer includes channels that are open opposite the membrane to allow for the flow of oxidant and fuel.

12. 8. The system of claim 7, wherein the gas diffusion layer is bounded by porous ribs to fuel and / or oxidant to allow flow therethrough for generating electricity at the membrane.

13. The system of claim 7 , wherein the coolant flow layer comprises an electrically conductive porous mesh flow layer.

14. 1. A method for use in manufacturing a fuel cell system, comprising: forming a plurality of openings in a non-conductive sheet, the openings being linearly spaced on the sheet; disposing a first metal separator on a first side of the sheet covering a first opening of the plurality of openings in a first sheet portion of the sheet; disposing a coolant flow layer within the first opening; disposing a second metal separator on a second side of the sheet covering the first opening; disposing a membrane in a second one of the plurality of openings in a second sheet portion of the sheet; disposing a first gas diffusion layer on a first side of the second opening and a second gas diffusion layer on a second side of the second opening; The method includes:

15. 15. The method of claim 14, further comprising the steps of connecting the first separator and the second separator to the sheet at the first opening and connecting the first gas diffusion layer and the second gas diffusion layer to the sheet at the second opening.

16. 15. The method of claim 14, wherein the first and second metal separators comprise flat aluminum foil plates, and further comprising coating the first and second metal separators with a coating to inhibit corrosion from fuel and / or oxidant and / or coolant contacting the first and second metal separators.

17. 15. The method of claim 14, wherein the first gas diffusion layer and the second gas diffusion layer include channels facing the first metal separator or the second metal separator for conducting oxidant and fuel flow.

18. 15. The method of claim 14, wherein the first gas diffusion layer and the second gas diffusion layer include ribs bounding channels, the ribs being porous to a fuel and / or an oxidant to allow flow therethrough for generating electricity at the membrane.

19. The method of claim 14 , wherein the coolant flow layer comprises an electrically conductive porous mesh flow layer.

20. The method of claim 14 further comprising forming a seal on the first metal separator or the sheet by an injection molding process.

21. 1. A method for use in manufacturing a fuel cell system, comprising: forming an opening in a non-conductive sheet; disposing a first metal separator on a first side of the sheet covering the opening in a first sheet portion of the sheet; disposing a coolant flow layer within the first opening; disposing a second metal separator on a second side of the sheet covering the opening; The method includes:

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