Fuel cell manifold assembly including a self-supporting polymer material liner

Abstract

An illustrative example embodiment of a fuel cell manifold device includes a self-supporting polymeric material-lined body that includes a generally planar main wall and a plurality of side walls. The side walls each extend generally perpendicularly from the main wall. Inner surfaces on the main wall and the side walls collectively define a cavity. The main wall has a length and a width that is less than the length. The main wall includes a plurality of ribs positioned along the main wall in the width direction. The ribs are spaced apart from one another in the length direction. The ribs allow for a degree of thermal expansion of the lined body.

Description

[0001] This application is a divisional application of application number 201780051646.4, filed August 17, 2017, entitled "Fuel Cell Manifold Assembly Including Self-Supporting Polymer Material Liner." BACKGROUND

[0002] Fuel cell devices provide electrical power based on electrochemical reactions. Some fuel cell arrangements use phosphoric acid as an electrolyte. Such fuel cells are commonly referred to as phosphoric acid fuel cells (PAFCs).

[0003] Fuel cell power plants typically include a cell stack assembly having a plurality of fuel cells. Manifolds can be positioned along at least one side of the cell stack assembly in order to direct reactants to the fuel cells. In some PAFCs, the manifolds are carbon steel and must be protected from the phosphoric acid. A common approach includes electrostatically coating the manifold plates with a perfluoroalkoxy polymer resin (PFA) coating. While such a coating provides a useful acid barrier and serves as a dielectric barrier on the metal manifold plates, the use of such a coating incurs additional expense. Multiple coating and sintering steps are typically required to form a coating that is thick enough to be an effective barrier.

[0004] An alternative approach is suggested in U.S. Patent No. 6,245,454. According to that document, a sheet of resin can be positioned inside the manifold plate rather than applying a coating to the plate. This approach is not without difficulties, as the installation technique can be cumbersome and the dimensional relationship of the sheet of resin to the manifold plate must accommodate different thermal expansion of the materials.

[0005] It would be useful to have an acid-resistant dielectric layer for fuel cell manifolds that does not have the expense or complexity associated with previous approaches. SUMMARY

[0006] An illustrative example embodiment of a fuel cell manifold device includes a self-supporting polymer material liner body including a generally planar main wall and a plurality of side walls. The side walls respectively extend generally perpendicularly from the main wall. Inner surfaces on the main wall and the side walls collectively define a cavity. The main wall has a length and a width that is less than the length. The main wall includes a plurality of ribs positioned along the main wall in the width direction. The ribs are spaced apart from one another in the length direction. The ribs provide flexibility to allow for a degree of thermal expansion of the liner body.

[0007] An illustrative example fuel cell manifold assembly includes a metal manifold plate. A self-supporting polymeric material liner is positioned adjacent an interior of the manifold plate. The liner has a channel around a perimeter of the liner, and a portion of the manifold is received in the channel. A reactant conduit adapter is received through a corresponding opening in the manifold plate and the liner. The reactant conduit adapter includes a flange that is received against an interior surface on the main wall of the liner, with an interface between the flange and the interior surface being sealed. Another portion of the reactant conduit adapter is adjacent an exterior of the manifold plate facing in an opposite direction from the interior surface on the main wall.

[0008] An illustrative example method of assembling a fuel cell manifold assembly includes positioning a self-supporting polymeric material liner adjacent an interior of a metal manifold plate, with an edge of the manifold plate at least partially received in a channel around a perimeter of the liner. A portion of a reactant conduit adapter is inserted through openings in the liner and the manifold plate until a flange on the reactant conduit adapter is received against an interior surface on the liner. The flange has an outer dimension that is greater than the openings. The flange is then secured to the manifold plate with the liner between the flange and the manifold plate. When the flange is secured, an interface between the flange and the liner is sealed.

[0009] Various features and advantages of at least one disclosed example embodiment will be made apparent from the following detailed description in connection with the drawings. The drawings can be briefly described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 Selected portions of an example fuel cell arrangement are schematically illustrated, including a manifold assembly designed in accordance with an embodiment of the present application.

[0011] Figure 2 An example manifold assembly designed in accordance with an embodiment of the present application is illustrated.

[0012] Figure 3 An example manifold plate and self-supporting polymeric liner configuration is illustrated.

[0013] Figure 4 Selected features of an example liner configuration are illustrated.

[0014] Figure 5 An example reactant conduit adapter is illustrated.

[0015] Figure 6 A portion of an assembly process for assembling an example manifold assembly is illustrated.

[0016] Figure 7 Another portion of an example assembly process is schematically illustrated.

[0017] Figure 8An example fastener is shown for securing a conduit reactant adapter in place within a manifold assembly. DETAILED DESCRIPTION

[0018] Figure 1 Selected portions of a fuel cell power plant 20 for generating electrical power based on electrochemical reactions are shown schematically. A plurality of individual fuel cells are assembled in a known manner in a cell stack assembly 22. A manifold assembly 24 positioned along one side of the cell stack assembly 22 facilitates providing reactants to the fuel cells. Another manifold assembly 26 is provided on the other side of the cell stack assembly 22.

[0019] Referring to Figure 2 and Figure 3 The manifold assembly 24 includes a metal manifold disk 30 having a main wall 32 and a plurality of side walls 34 extending generally perpendicularly from edges of the main wall 32. The inner surfaces on the main wall 32 and the side walls 34 define a cavity established by the metal manifold disk 30. The main wall 32 has an opening 36.

[0020] A self-supporting polymeric material liner 40 is positioned adjacent the interior of the metal manifold disk 30. The liner 40 has a main wall 42 and a plurality of side walls 44 extending generally perpendicularly from edges of the main wall 42. A lip 46 at the end of the side walls 44 distal from the main wall 42 includes a portion parallel to the main wall 42 and a portion parallel to the corresponding side wall 44.

[0021] The side walls 44 and the lip 46 establish a channel around the perimeter of the main body of the liner 40. The channel faces in a direction opposite the inner surface on the main wall 42. In Figure 2 and 3 The inner surface of the main wall 42 is visible in

[0022] The main body of the liner 40 has a length L and a width W that is less than the length. In some example embodiments, the length is greater than two meters (six feet). The liner 40 is self-supporting or free-standing in that it maintains its shape without being dependent on being received adjacent the manifold disk 30. The liner 40 in this example is made of a thermoplastic polymer that is resistant to acid and water vapor. The polymeric material of the liner 40 has good strength at high temperatures, is thermoformable, and is relatively inexpensive, such that the liner 40 establishes an effective acid barrier in the manifold assembly 24 in an economical manner.

[0023] An example material that can be used in an exemplary embodiment of lining 40 is polyphenylene sulfone (PPSU). This material is useful because it has good chemical resistance, good high-temperature properties (e.g., low coefficient of expansion and high strength), and is relatively inexpensive. Other embodiments include materials for lining 40 such as polyetheretherketone (PEEK), polyaryletherketone (PAEK), and polyphenylene sulfide (PPS). This material is superior to polytetrafluoroethylene (PTFE) because PTFE does not have sufficient high-temperature mechanical properties.

[0024] Example embodiments include using thermoforming techniques such as curtain forming to form the liner 40. The thermoforming techniques used to form the liner 40 allow for rapid manufacturing of the liner, saving time and manufacturing costs. The thermoforming techniques contribute to the self-supporting properties of the liner 40. Additionally, the freestanding, self-supporting liner 40 can be quickly and relatively easily assembled with the metal manifold disc 30 during the assembly process.

[0025] As used herein, the terms "self-supporting" or "freestanding" mean that the liner has a defined shape and that the liner body is at least able to maintain its own shape without the need for another component adjacent to it. For example, the liner body 40 defines a cavity based on its self-supporting features. The self-supporting aspect of the liner includes positioning the sidewalls 44 generally parallel to the main wall 42.

[0026] The illustrated example liner 40 includes a plurality of ribs 50 extending in the width direction on the body of the liner 40. The ribs 50 are spaced apart from each other in the length direction. In the illustrated example, the ribs 50 are approximately six inches (0.15 meters) apart. The ribs 50 provide flexibility to allow for a degree of thermal expansion of the body of the liner 40. When the liner 40 is subjected to high temperatures during fuel cell operation, the ribs 50 mitigate the effects of thermal expansion of the material. The ribs 50 also reduce deflection of the liner, which would otherwise occur due to the thermal expansion of the polymer when exposed to higher fuel cell operating temperatures. The ribs 50 provide localized areas or regions of the liner 40 that can withstand a degree of thermal expansion while the overall shape of the liner remains unchanged. For example, one or more of the ribs 50 may be at least partially flattened because the heat associated with fuel cell operation causes or induces thermal expansion along the length direction.

[0027] like Figure 4 As shown, the channel surrounding the liner 40 has a greater width near one end of the liner 40. As shown at 54, the channel has a greater width near the bottom of the liner body (as illustrated). The greater width in the channel accommodates variations in the manufacturing dimensions of the manifold disc 30 or the liner 40. In other words, the greater width of the channel near one end of the liner 40 accommodates manufacturing tolerances associated with making the manifold disc 30 and the liner 40 separate pieces. In some example embodiments, the wider portion of the channel exists near both ends of the liner 40.

[0028] refer to Figures 5-8 The reactant conduit adapter 60 facilitates connection of the reactant source to the manifold assembly 24. One end 62 of the adapter 60 is positioned on the outer side of the manifold assembly 24, near the outward-facing surface of the manifold disc 30. A flange 64 is provided on the opposite end of the adapter 60, and a seal 66 is provided on one side of the flange 64. The seal 66 may be a separate gasket, coating, or layer of material on the side of the flange 64 facing the main wall 42 of the liner 40. The flange 64 is larger than the opening 36 in the manifold disc 30 and the opening 48 in the liner 40.

[0029] like Figure 6 As shown, the first end 62 is inserted from the inside of the liner 40 through openings 38 and 36. The transition portion 68 of the adapter 60 is fitted through openings 36 and 48 and has a portion with external dimensions substantially the same as those of openings 36 and 48. The adapter 60 is manipulated until the flange 64 is received against the inner surface of the main wall 42 of the liner 40. Multiple fasteners 70 have portions 72 configured to mate with and be secured to the manifold disc 30. In some examples, portions 72 are threaded, and the manifold disc 30 includes a threaded hole surrounding opening 36. The fasteners 70 include a seal 74 that is received against the flange 64 when the fastener is fully inserted to secure the flange 64 against the main wall 42 of the liner. The head portion 76 on the fastener 70 is larger than the size of the hole 78 through the flange 64 to hold the adapter 60 in the desired position relative to the manifold disc 30 and the liner 40, and the interface between the flange 64 and the inner surface of the main wall 42 is sealed by the seal 66.

[0030] The manifold assembly of the type shown in the example embodiment offers cost savings for PAFC systems. The self-supporting, freestanding liner 40 is simpler and cheaper to manufacture than applying a coating to a metal manifold disc. The time, material, and processing savings associated with the liner 40 make the manifold assembly 24 and the overall PAFC system more economical.

[0031] The foregoing description is illustrative in nature and not restrictive. Variations and modifications of the disclosed exemplary embodiments will be apparent to those skilled in the art, and such variations and modifications do not necessarily depart from the spirit of the invention. The scope of legal protection afforded to this disclosure can only be determined by reading the following claims.

Claims

1. A fuel cell manifold apparatus comprising a self-supporting polymeric material liner body, the polymeric material liner body comprising a planar main wall and a plurality of side walls each extending perpendicularly from the main wall, inner surfaces on the main wall and the side walls collectively defining a cavity, the main wall having a length and a width that is less than the length, the main wall comprising a plurality of ribs positioned along the main wall in a widthwise direction, the plurality of ribs being spaced apart from one another in a lengthwise direction, the plurality of ribs providing flexibility for material expansion to allow for a degree of thermal expansion of the liner body and to mitigate effects of thermal expansion of the liner body and to reduce deflection of the liner body when the liner body is subjected to high temperatures during fuel cell operation, wherein, When heat associated with fuel cell operation causes or induces thermal expansion along a length direction, one or more of the ribs can at least partially flatten, and wherein the ribs provide local regions of the liner body that can undergo a degree of thermal expansion while an overall shape of the liner body remains unchanged; wherein the liner body includes a plurality of lips proximate to ends of the side walls distal from the main wall, the lips including portions parallel to the main wall and portions parallel to the corresponding side wall; wherein the side walls and the lips establish a channel around a perimeter of the liner body, and wherein the channel has a greater width proximate to at least one end of the liner body compared to a width of other portions of the channel, wherein the fuel cell manifold assembly includes a metal manifold disc, at least a portion of a side wall on the manifold disc is received in the channel when in an assembled state; and wherein the fuel cell manifold assembly further includes: an opening through the main wall; and a reactant conduit adapter at least partially received in the opening, an interface between the reactant conduit adapter and the main wall is sealed by a seal.

2. The fuel cell manifold assembly of claim 1, wherein the channel has one side defined by at least a portion of the side wall, the channel facing in a direction opposite an inner surface of the main wall.

3. The fuel cell manifold apparatus of claim 2 wherein, the channel has a first width proximate to one end of the main wall and a second width proximate to an opposite end of the main wall that is greater than the first width.

4. The fuel cell manifold assembly of claim 2, wherein, an inner side of the metal manifold disc is positioned proximate to an outer surface on the main wall of the liner body.

5. The fuel cell manifold assembly of claim 1, wherein, the reactant conduit adapter includes a flange that is received against an inner surface of the main wall, wherein the seal is selected from one of a separate gasket, coating, or layer of material on a side of the flange facing the main wall of the liner body; and the flange at least partially surrounds an opening through the main wall.

6. The fuel cell manifold assembly of claim 5, including a plurality of fasteners that secure the flange to the main wall.

7. The fuel cell manifold assembly of claim 5, wherein the metal manifold disc has an opening through the metal manifold disc that is aligned with the opening through the main wall of the liner body.

8. The fuel cell manifold assembly of claim 6, the plurality of fasteners secure the flange to the metal manifold disc, and a portion of the main wall is between the flange and the metal manifold disc.

9. A fuel cell manifold assembly, comprising: a metal manifold disc; a liner body having a main wall and a plurality of side walls extending from the main wall, the side walls and the main wall establishing a channel around a perimeter of the liner body, and wherein the channel has a greater width proximate to at least one end of the liner body compared to a width of other portions of the channel, wherein the fuel cell manifold assembly includes a reactant conduit adapter at least partially received in the channel, and an interface between the reactant conduit adapter and the main wall is sealed by a seal. for a self-supporting polymeric material liner, the liner including a main wall positioned proximate an interior of the metallic manifold plate and a plurality of side walls, the main wall having a length and a width that is less than the length, the main wall including a plurality of ribs positioned along the main wall in a widthwise direction, the plurality of ribs spaced apart from one another in a lengthwise direction, and the plurality of ribs providing flexibility for material expansion to allow for a degree of thermal expansion of the liner and to mitigate effects of thermal expansion of the liner and reduce deflection of the liner when the liner is subjected to high temperatures during fuel cell operation, the liner having a channel around a perimeter of the liner, a portion of the metallic manifold plate being received in the channel; and a reactant conduit adapter received through an opening in each of the metallic manifold plate and the liner, the reactant conduit adapter including a flange received against an interior surface on the main wall of the liner with an interface between the flange and the interior surface being sealed, another portion of the reactant conduit adapter being adjacent an exterior of the metallic manifold plate facing in a direction opposite an interior surface on the main wall; wherein the liner further including a plurality of lips proximate ends of the side walls distal from the main wall, the lips including portions parallel to the main wall and portions parallel to the corresponding side walls; wherein the side walls and the lips establish the channel around the perimeter of the liner, and wherein the channel has a greater width proximate at least one end of the liner than a width of other portions of the channel; wherein the fuel cell manifold assembly includes a seal between the flange and the interior surface on the main wall, and wherein one or more of the ribs are capable of at least partially flattening when thermal associated with fuel cell operation causes or induces thermal expansion in the lengthwise direction, and wherein the ribs provide that a local region of the liner is capable of undergoing a degree of thermal expansion while an overall shape of the liner remains unchanged.

10. The fuel cell manifold assembly of claim 9, wherein, the flange around the opening in the main wall.

11. The fuel cell manifold assembly of claim 9, including a plurality of fasteners securing the flange to the metallic manifold plate with a portion of the main wall between the flange and the metallic manifold plate.

12. The fuel cell manifold assembly of claim 11, including a seal associated with each of the fasteners configured to prevent migration of gas or acid from an interior of the liner toward the metallic manifold plate.

13. The fuel cell manifold assembly of claim 9, wherein, the side walls each extend perpendicularly from the main wall, the interior surface on the main wall and the interior surface on the side walls collectively defining a cavity.

14. The fuel cell manifold assembly of claim 9, wherein the seal is selected from one of a separate gasket, a coating, or a layer of material on a side of the flange facing the main wall of the liner.

15. The fuel cell manifold assembly of claim 9, wherein, the channel faces in a direction opposite the interior surface of the main wall.

16. The fuel cell manifold assembly of claim 9, wherein, the channel has a first width proximate one end of the main wall and a second width proximate an opposite end of the main wall that is greater than the first width.

17. A method of assembling a fuel cell manifold apparatus according to any of claims 1-8, the method comprising: positioning a self-supporting polymeric liner body adjacent an interior of a metal manifold disk, and an edge of the metal manifold disk being at least partially received in a channel around a perimeter of the liner body; inserting a portion of a reactant conduit adapter through an opening in the liner body and the metal manifold disk until a flange on the reactant conduit adapter is received against an interior surface on the liner body, the flange having an outer dimension that is larger than a size of the opening; and securing the flange to the metal manifold disk, and the liner body being located between the flange and the metal manifold disk, an interface between the flange and the liner body being sealed when the flange is secured.

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