INTEGRATED CIRCUIT FOR DIAGNOSTICS

Abstract

A fuel cell system includes a membrane electrode assembly, a first plate separator and a second plate separator on opposite sides of the membrane electrode assembly. The first plate separator and the second plate separator have exterior ends away from the membrane electrode assembly. A first gas diffusion layer is located between the first plate separator and the membrane electrode assembly. A second gas diffusion layer is located between the second plate separator and the membrane electrode assembly. The sub-gasket extends from the membrane electrode assembly laterally toward at least one of the exterior ends. A first seal is located between the first plate separator and the sub-gasket. A conductive trace is attached to the sub-gasket and extends on the sub-gasket from an exterior side of the first seal to a location on an interior side of the first seal.

Claims

1. A fuel cell system comprising: a membrane electrode assembly; a first plate separator and a second plate separator on opposite sides of said membrane electrode assembly, said first plate separator and said second plate separator having exterior ends away from said membrane electrode assembly; a first gas diffusion layer between the first plate separator and the membrane electrode assembly; a second gas diffusion layer between the second plate separator and the membrane electrode assembly; a subgasket extending from the membrane electrode assembly laterally toward at least one of said exterior ends; a first seal located between the first plate separator and the subgasket; a conductive trace attached to said subgasket and extending on said subgasket from an exterior side of said first seal to a location on an interior side of said first seal.

2. The system of claim 1 wherein said subgasket comprises a first top side adjacent said first seal and said first gas diffusion layer and a second bottom side adjacent said second gas diffusion layer, said conductive trace located on said first top side and a second conductive trace located on said second bottom side.

3. The system of claim 2 wherein said second trace extends through said subgasket to said first side to allow an electrical connection between said first trace and said second trace and a sensor or controller.

4. The system of claim 1 wherein said subgasket and said trace extend outwardly past said at least one of said exterior ends.

5. The system of claim 1 wherein said trace extends from said first gas diffusion layer between said first seal and said subgasket toward said exterior end.

6. The system of claim 1 wherein said conductive trace comprises a first linear portion extending from said exterior side of said first seal toward said membrane electrode assembly and said conductive trace further comprising an upwardly extending portion extending toward said first plate separator.

7. The system of claim 1 wherein said subgasket comprises a tab extending beyond at least one of said exterior ends in a direction away from said membrane electrode assembly, said conductive trace extending on said subgasket past at least one of said exterior ends, said tab having a longitudinal axis in a direction away from at least one of said exterior ends.

8. The system of claim 7 wherein said subgasket further comprises a second trace on a same side of said subgasket as said conductive trace.

9. The system of claim 7 further comprising a second subgasket connected to a second membrane electrode assembly, said subgasket and said second subgasket vertically spaced along a vertical axis connecting said first plate separator and said second plate separator, said second subgasket comprising a second tab, said second tab located in a lateral direction relative to said first tab, such that said first tab and said second tab are vertically offset relative to each other and non-vertically aligned.

10. The system of claim 1 wherein said conductive trace is a metal trace printed on said subgasket.

11. The system of claim 1 wherein said membrane electrode assembly, said first gas diffusion layer, said second gas diffusion layer are bonded to said subgasket.

12. The system of claim 8 wherein said conductive trace and said second trace comprise a thermocouple junction.

13. A method for use in manufacturing a fuel cell system comprising: attaching a conductive trace to a subgasket; locating a membrane electrode assembly on the subgasket such that a lateral portion of the subgasket extends away from the membrane electrode assembly toward an exterior of a fuel cell subassembly; locating a first gas diffusion layer on a first side of the membrane electrode assembly and a second gas diffusion layer on a second side of the membrane electrode assembly; the conductive trace extending between a seal and the subgasket from an interior of the fuel cell subassembly past a seal toward an exterior of fuel cell subassembly.

14. The method of claim 13 further comprising locating a first plate separator on the first gas diffusion layer and the seal contacting the first plate separator and the subgasket.

15. The method of claim 13 further comprising locating a first plate separator and a second plate separator on opposite sides of the membrane electrode assembly, the first plate separator and the second plate separator having exterior ends away from said membrane electrode assembly, the conductive trace extending from the interior past at least one of the exterior ends.

16. The method of claim 13 wherein the attaching the conductive trace to the subgasket comprises depositing a conductive material on the subgasket to form the trace.

17. The method of claim 13 wherein the attaching the conductive trace to the subgasket comprises attaching the conductive trace to a first side of the subgasket and further comprising attaching a second trace on a second opposite side of the subgasket and through the subgasket to the first side.

18. The method of claim 13 wherein said subgasket comprises a tab extending away from the interior toward the exterior such that a longitudinal axis of the tab extends away from the interior, the conductive trace extending longitudinally on the tab away from the interior.

19. The method of claim 13 further comprising locating a second subgasket connected to a second membrane electrode assembly in the fuel cell subassembly such that the second subgasket is vertically spaced along a vertical axis of the subassembly and a second tab of the second is located in a lateral direction relative to the first tab, such that the first tab and the second tab are vertically offset relative to each other and non-vertically aligned.

20. The method of claim 13 further comprising locating a second conductive trace on a same side of said subgasket as the conductive trace, the second conductive trace extending from the interior to toward the exterior past the seal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention will be readily understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings in which:

[0012] FIG. 1 is a block diagram of a fuel cell system in accordance with the invention;

[0013] FIG. 2 is an exploded schematic view of a portion of a fuel cell of the fuel cell system of FIG. 1;

[0014] FIG. 3 is an exploded view of a portion of the fuel cell of the system of FIG. 2;

[0015] FIG. 4 is a side cross-sectional view of a portion of the fuel cell system of FIG. 3 with wires connected to fuel cell plates thereof to provide connection to other devices;

[0016] FIG. 5 is a side cross-sectional view of a portion of the fuel cell system of FIG. 3 with metalized traces on a sub-gasket connected to gas diffusion layers thereof;

[0017] FIG. 6 is a side cross-sectional view of a portion of the system of FIG. 3 showing a metalized trace on a sub-gasket connected to a gas diffusion layer;

[0018] FIG. 7 is a side cross-sectional view of a portion of a fuel cell system according to FIG. 3 with a metalized trace on a sub-gasket having an upwardly projecting portion;

[0019] FIG. 8 is a side cross-sectional view of a portion of a fuel cell system according to FIG. 3 with a metalized trace on a sub-gasket having an upwardly projecting portion;

[0020] FIG. 9 is a perspective view of a sub-gasket having a tab and receiving a membrane electrode assembly in accordance with an aspect of the present invention;

[0021] FIG. 10 is an enlarged perspective view of the tab of FIG. 9;

[0022] FIG. 11 is a perspective cross-sectional view of a plurality of sub-gaskets receiving membrane electrode assemblies with the sub-gaskets having staggered tabs in accordance with an aspect of the present invention;

[0023] FIG. 12 is an exploded view of the sub-gaskets of FIG. 11;

[0024] FIG. 13 is a top view of a sub-gasket having a plurality of traces in accordance with an aspect of the present invention in accordance with an aspect of the present invention;

[0025] FIG. 14 is side cross-sectional view of a portion of the fuel cell system of FIG. 3 with metalized traces on a sub-gasket connected to gas diffusion layers thereof and an external monitoring or control device in accordance with an aspect of the present invention;

[0026] FIG. 15 is a top view of a sub-gasket including a thermal couple junction formed of metal traces in accordance with an aspect of the present invention;

[0027] FIG. 16 is a side cross-sectional view of a fuel cell system including the thermal couple junction of FIG. 15; and

[0028] FIG. 17 is a side cross-sectional view of a fuel cell system including a plurality of fuel cells having a device connected to multiple fuel cells thereof for powering the device in accordance with an aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be discussed hereinafter in detail in terms of various exemplary embodiments according to the present invention with reference to the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, 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 in order to avoid unnecessary obscuring of the present invention.

[0030] Thus, all the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, in the present description, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in FIG. 1.

[0031] 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 attached drawings, and described in the following specification, are simply 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.

[0032] In accordance with the principals of the present invention, fuel cell systems and methods for manufacturing a fuel cell stack are provided. In an example depicted in FIG. 1, a fuel cell system 101 is referred to as the assembled, or complete, system which functionally together with all parts thereof produces electricity and typically includes a fuel cell stack 20 and an energy storage device 30. The fuel cell is supplied with a fuel 13, for example, hydrogen, through a fuel inlet 17. Excess fuel 18 may be exhausted from the fuel cell through a purge valve 90 and may be diluted by a fan 40. In one example, fuel cell stack 20 may have an open cathode architecture of a PEM fuel cell, and combined oxidant and coolant, for example, air, may enter through an inlet air filter 10 coupled to an inlet 5 of fuel cell stack 20. Excess coolant/oxidant and heat may be exhausted from a fuel cell cathode of fuel cell stack 20 through an outlet 11 to fan 40 which may exhaust the coolant/oxidant and/or excess fuel to a waste exhaust 41, such as the ambient atmosphere. The fuel and coolant/oxidant may be supplied by a fuel supply 7 and an oxidant source 9 (e.g., air), respectively, and other components of a balance of plant, which may include compressors, pumps, valves, fans, electrical connections and sensors. In other examples, the oxidant and coolant described could be separated with a separate liquid coolant utilized.

[0033] FIG. 2 depicts a schematic exploded view of an internal subassembly 100 of fuel cell stack 20 of FIG. 1 including a cathodic plate separator 110 at an outer end 115 and a plate separator seal 120 on an inner side thereof. A membrane electrode assembly (MEA) 130 is located between seal 120 and a second plate separator seal 150. An anode plate separator 160 is on a second end 165 of subassembly 100.

[0034] MEA 130 includes a membrane 140 (e.g., an ion conducting membrane) between a cathode side catalyst layer 125 and an anode side catalyst layer 135. A cathode side gas diffusion layer (GDL) 122 is located between cathode side catalyst layer 125 of the membrane electrode assembly and plate separator 110. An anode side gas diffusion layer 145 is located between anode side catalyst layer 135 of the membrane electrode assembly and plate separator 160. Seal 120 and seal 150 may be received in a channel of on an inner side of plate separator 110 and plate separator 160, respectively. In another example, such seals may be injection molded around an MEA (e.g., MEA 130) or another fuel cell to provide a sealing function, such as between an MEA and fuel cell plate separators.

[0035] FIG. 3 depicts a repeating portion 103 of internal subassembly 100 in an exploded view similar to FIG. 2 except that the seals (i.e., seal 120 and seal 150) are omitted for clarity, and cathode plate separator 110 is omitted. A seal or subgasket 300 is located between cathode side catalyst layer 125 and an anode side catalyst layer 135 with MEA 130 being received in a cavity 146 of subgasket 300. A gasket or seal 170 may be located below plate separator 160.

[0036] As indicated, MEA 130 may be received in opening 146 of subgasket 300 which may be formed of a nonconductive material, such as a polymer. As depicted, MEA 130 may be attached to anode GDL 145 (e.g., via heat sensitive adhesive) and a combined MEA 130-GDL 145 may be sandwiched with GDL 122 around subgasket 300 such that the components are attached to each other. For example, the combination may be formed by hot pressing aligned anode and cathode portions (e.g., MEA 130-GDL 145 and GDL 122) to attach such portions to subgasket 300. In an example, heated platens may hold the gas diffusion layers (gas diffusion layer 122, gas diffusion layer 145) and membrane electrode assembly 130 while bonding (e.g., via heat sensitive adhesive or bonding gas diffusion layers to the MEA) occurs to subgasket 300.

[0037] In an example depicted in FIG. 4, subassembly 100 includes opposing bipolar plates 102 (e.g., plate separator 110 and plate separator 160) each of which may be connected to one of wires 3 for connecting to a controller or sensor for monitoring and/or controlling purposes, for example.

[0038] In an example depicted in FIG. 5, metal traces 200 may be connected to GDLs (e.g., GDL 122 and GDL 145) on opposite sides of a membrane (e.g., membrane 140). As depicted, a first top trace 205 of traces 200 may be attached to, and located on, a first side (e.g., a top side as depicted) 301 of subgasket 300 while a second bottom trace 207 may be attached to, and located on, a second side 302 thereof and may extend vertically therethrough (e.g., through a via) to first side 301. The metal traces (e.g., traces 200) may printed on a subgasket (e.g., subgasket 300) during a metallized printing process or via another method (e.g., vacuum metallization, arc or flame spraying, plating) of depositing a metal or other conductive strip or trace on the gasket. An opening or via may be placed through subgasket after which a metal or other conductive material may be printed or otherwise located in the opening to form a metallized via allowing a bottom trace (e.g., second trace 207) to have an upwardly extending portion 203 extending through a gasket (e.g., gasket 300)

[0039] Traces 200 may include electrical connectors 201 (e.g., formed of a conductive metal or a same material as traces 200) on ends thereof opposite the GDLs (e.g., GDL 122 and GDL 145) to allow an electrical connection of the traces (e.g., traces 200) and thus the GDLs to one or more controllers, sensors, or other devices external to subassembly 100. For example, the traces may be connected to a voltage sensor or computerized controller.

[0040] As described above, traces 200 may connect to the GDLs (e.g., GDL 122 and GDL 145) to provide an electrical connection between the GDLs and connectors 201 to allow an external connection to the GDLs for purposes of monitoring and or controlling subassembly 100 and fuel cell stack 20. For example, subgasket 300 and traces 200 may extend from GDL 122 and/or GDL 145 toward an exterior of subassembly 100. Subgasket 300 and traces 200 may extend outwardly past an outermost or exterior end 111 of plate separator 110 and/or an outermost or exterior end 161 of plate separator 160, for example. Connectors 201 could be located to an exterior of outer end 111 and/or outer end 161 as depicted. The location of the connectors outside the plate separators and seal 120 and/or seal 150 may allow additional spacing (due to the exterior location) to facilitate an easier connection of the connectors to external devices, such as sensors and controllers.

[0041] FIG. 6 depicts a portion of FIG. 5 including portions of top trace 205, plate separator 110, GDL 122, membrane 140, and subgasket 300. Top trace 205 extends between subgasket 300 and seal or gasket 120 and is received under GDL 122 and on top of subgasket 300. More specifically, a GDL end 206 of top trace 205 opposite connectors 201 contacts, and may be connected to, GDL 122 to provide a connection between GDL 122 and top trace 205 thereby providing an electrical connection between GDL 122 and a first connector 202 (FIG. 5) of connectors 201. Second trace 207 may extend between subgasket 300 and seal or gasket 150 and be received under GDL 145 and on top of subgasket 300, as depicted in FIG. 5, for example. Further, second trace 207 may extend through subgasket as described above.

[0042] In another example, depicted in FIG. 7, first trace 205 may include a vertically extending spike 210 on or near an end 211 thereof to allow a further penetration of trace 205 into GDL 122 relative to a laterally extending portion 212 and end 211 of trace 205. Spike 210 may extend into GDL 122 (but may avoid extending through GDL 122 into plate separator 110) to provide a better electrical connection (due to a larger surface area and dimensional extent) between trace 205 and thus connector 202 relative to GDL 122. First trace 205 having spike 210 may be formed via additional metal or other conductive material being deposited (e.g., printed) on trace 205 to form spike 210 during formation of first trace 205 or in a subsequent step. For example, spike 210 may be formed by stamping a metallized plastic forming trace 205. Further, spike 210 may be formed by folding and cutting such metallized plastic. Second trace 207 (not depicted in FIG. 7) may extend between subgasket 300 and seal or gasket 150 and be received under GDL 145 and on top of subgasket 300, as depicted in FIG. 5, for example. Further, second trace 207 may extend through subgasket as described above.

[0043] In a further example depicted in FIG. 8, a trace 208 may be substituted for first trace 205, relative to the description above, and an upwardly extending portion 209 thereof may extend upwardly from a portion 204 of trace 208 connected to subgasket 300 at a lateral position relative to GDL 122 such that trace 208 does not extend between gasket 120 and subgasket 300. Upwardly extending portion 209 of trace 208 may be formed via the methods described for spike 210 and may extend upwardly to contact plate separator 110. A second trace (not shown) may be substituted for second trace 207, relative to the description above, and may be located extend along an opposite side of subgasket 300 vertically relative to trace 208 and may similarly extend downwardly to contact plate separator 160. Such second trace could also extend through subgasket 300 similar to trace 207.

[0044] In an example depicted in FIGS. 9-10, a subgasket 305 may be connected to an MEA 330 and a trace 310 may be received on subgasket 130, similar to that described above relative to subgasket 300, MEA 130 and trace 205. Further, subgasket 305 may include a projecting tab 340 and trace 310 may extend from a GDL 312 similar to GDL 122 and GDL 145 described above. Further, a second trace (not shown) may be located on an opposite side of subgasket 305 similar to trace 207 described above. Connectors 350 may be located on subgasket 305 (e.g., tab 340) and connect to the traces to allow an external device (e.g., a voltage sensor or electronic controller) to connect to the traces and thus the GDL's (not shown) on opposite sides of the MEA. Tab 340 may have a longitudinal dimension extending away from a remainder of gasket 305 and a fuel cell stack (e.g., fuel cell stack 20) sized (along with a transverse dimension thereof) to allow connectors 350 to be spaced from an outside surface or casing of a subassembly (e.g., subassembly 100) or a fuel cell stack (e.g., fuel cell stack 20). Such spacing may facilitate the connection to the device and/or facilitate operation of a device to be connected to the connectors. Also, tab 340 may have a transverse width dimension which is smaller than the indicated longitudinal dimension which may allow multiple such tabs to be located adjacent one another in a lateral direction to facilitate multiple connections to various fuel cells or other components of a fuel cell stack (e.g., fuel cell stack 20).

[0045] FIGS. 11-12 depict multiple subgaskets 500 similar to subgasket 305, but with each subgasket having tabs 510 (similar to tab 340) staggered or located laterally to each other along longitudinal dimensions of the gaskets (which may be have edges thereof aligned) and accompanying subassembly or fuel cell stack (e.g., fuel cell stack 20). As indicated, the lateral location of the tabs relative to each other may facilitate connection to multiple devices (e.g., sensor(s) or controller(s)) along longitudinal dimensions of the gaskets and may provide space (e.g., due to a longitudinal extension of the tabs from a remainder of the fuel cell stack and the lateral location of the tabs relative to each other) for connections to such devices and/or provide space between the tabs and devices to allow better functioning of the devices.

[0046] FIG. 13 depicts another example of a subgasket 550, similar to the subgaskets (e.g., subgasket 300, subgasket 305, subgaskets 500) as described above, except that subgasket 550 includes multiple conductive traces attached thereto via metallized printing or other deposition. For example, subgasket 550 may include traces 560 which extend along subgasket 550 to various locations to allow an electrical connection between such locations and connectors 570 located on a tab 580 similar to the tabs (e.g., tab 340, tab 510) described above. Further, such traces (e.g., traces 560) may lead from tab 580 to sensors or other devices located on or adjacent to subgasket 550.

[0047] FIG. 14 is identical to FIG. 5 except that a device 600 is connected to connectors 201 of subassembly 100. In one example, device 600 could be a voltage sensor. The connection of the traces (e.g., trace 205, trace 207) to the GDLs (e.g., GDL 122 and GDL 145) may allow such a sensor to measure a voltage relative to each side of the membrane (e.g., membrane 140) with a circuit thus formed powered by the fuel cell (e.g., subassembly 100) at 0.6 to 0.9 V when operating properly, for example. Examples of voltage sensors that may be used with the described subassembly are described in co-owned US Patent Application No. ______(attorney docket no. 1404.333). Device 600 could also be an electronic controller, temperature sensor or other device for monitoring fuel cell stack (e.g., fuel cell stack 20)

[0048] In an example depicted in FIGS. 15-16, a subgasket 650 may include a first trace 660 and a second trace 670 formed of dissimilar metal types such that differences in temperature would cause changes in electrical potential thereby creating a thermal coupled junction 680. More specifically, second trace 670 may overlay first trace 660 and thermocouple junction 680 such that a change in temperature may be sensed through an electrical connection between the first trace and second trace. As depicted in FIG. 16, a seal 690 may electrically insulate thermocouple junction 680 from GDL 122. In an example, an increase or decrease in temperature may be sensed through an electrical connection between first trace 660 and/or second trace 670 and GDL 122.

[0049] As depicted in FIG. 17, a device 700 may be electrically connected to tabs (e.g., tab 340, tab 510, FIGS. 11-12) of multiple fuel cells of a fuel cell stack (e.g., fuel cell stack 2). Such connection to multiple fuel cells within a stack may provide sufficient power to power a device, such as device 700, which may be utilized to measure aspects of the fuel cell stack, control elements (e.g., motors or other balance of plant) of the stack or provide other necessary functions. Similarly, a device, such as device 700, could be utilized to provide measurements of the stack being powered by the stack at higher electrical potentials.

[0050] In an example not depicted, tabs (e.g., tab 340, tab 510) could have outermost edges or lateral edges which may be conductive (e.g., conductive material, such as metal, may be printed or otherwise deposited thereon) and connected to traces (e.g., traces 205, 208, 208, 310, 560) such as those described above which may connect to interior aspects of a fuel cell stack (e.g., fuel cell stack 20). Such conductive tabs may be vertically aligned to allow electrical connections therebetween tabs to allow electrical connection between vertical or lateral portions of a fuel cell stack (e.g., fuel cell stack) to facilitate the connection of sensors and/or controllers to such various portions of a stack as described above.

[0051] Fuel cell subassembly 100 may be manufactured using a method based on using a web or plastic sheet which connects components of a fuel cell stack (e.g., fuel cell stack 20) during its manufacture as described in co-owned U.S. patent application Ser. No. 17/572,679 filed Jan. 11, 2022. Alternatively, the manufacture of assembly 100 and portions thereof may be performed manually or a combination of such automated and manual methods.

[0052] Although the above-described examples of conductive traces (e.g., trace 200, trace 205, trace 207, trace 208, trace 310, trace 560) refer to such traces being printed, deposited or otherwise located on, connected to, or adjacent, plate separator 110, GDL 122 and membrane 140, the methods of connection of such traces may be utilized with other plate separators, GDLs and systems described herein. For example, such traces may be located on other subgaskets connected to MEAS in multiple fuel cells in a fuel cell stack (e.g., fuel cell stack 20).

[0053] While several aspects of the present invention have been described and depicted herein, alternative aspects may be affected by those skilled in the art to accomplish the same objectives. Accordingly, it is intended by the appended claims to cover all such alternative aspects as being within the true spirit and scope of the invention.