This application is based on and claims priority under 35 U.S.C. ยง 119 with respect to German Application No. 102 50 434.2 filed on Oct. 30, 2002, the entire content of which is incorporated herein by reference.
The invention generally relates to the sealing of fuel cells. More particularly, the present invention pertains to a module for a fuel cell arrangement, a process for producing such a module and a fuel cell arrangement produced with such a module.
Fuel cell arrangements are used to produce electrical energy by a chemical reaction and can be implemented, for example, in the form of a block which has a host of individual modules stacked on top of one another and in which the chemical reaction proceeds in each module. The reaction partners are often supplied to the fuel cell in a gaseous state, for example in the form of hydrogen and oxygen or air, and so reliable sealing of the fuel cell arrangement is necessary.
One example of a seal for fuel cells is described in German Offenlegungsschrift No. DE 100 28 395 A1. This document discloses a seal having a carrier body with elastomer material located on it. The elastomer material is applied to the support body in the form of a liquid rubber vulcanizate and is then cross-linked or vulcanized.
European Patent Publication No. EP 1 032 065 A2 discloses a seal arrangement especially for bipolar plates with interposed ion exchange-membrane units in fuel cells. In this seal arrangement, the seal elements of polymer material are injected into recesses of the bipolar plates and, with the pertinent bipolar plate, form an integral unit. The seal elements do not completely fill the recesses. Instead, empty spaces or gaps remain between the side walls of the seal elements and the adjacent walls of the recesses. This ensures that the seal elements can give when compressed. Moreover the seal elements project out of the recesses, i.e. the height of the seal elements is greater than the depth of the recesses.
A module for a fuel cell arrangement having several stacked plates is configured so that at least two of the plates have a common seal element of polymer material which is injected onto the plates and by which the plates are at least partially joined to one another. This arrangement makes it possible to reduce the number individual parts necessary for assembling the fuel cell arrangement with a comparatively small number of working steps. At the same time, the seal element can mechanically fix the plates without engaging in significant additional measures.
The plates can be connected to one another via the sealing element by adhesion. Likewise the plates can also be interlocked to one another. Further, a combination of the two types of connections is also possible. In this way generally, it is possible to produce a connection between the plates which is suitable for the respective application.
The seal element is preferably made on the two main surfaces of the stack which is formed by the plates. When the modules are stacked on top of one another into a fuel cell arrangement, relatively good sealing between the modules can be achieved. Also, the seal element can seal the intermediate space formed between adjacent plates. Thus, by way of the seal element, it is possible to achieve not only sealing between the individual modules, but also sealing between the individual plates of a module.
It is possible to configure and position the seal element so that it encompasses the end faces of the plates, at least in areas. It is also possible for the seal element to extend through at least one opening in the plates. To do this, in adjacent plates especially, oblong openings can be formed, with the openings of one plate and the openings of the other plate overlapping. The seal element can also extend in at least one tunnel-like cavity between the plates. Generally the tunnel-like cavity has at least one opening.
Numerous variations for the specific configuration of the connection of the plates by way of the seal element are possible. In preferred forms of all embodiments, both an adhesive and a positive (mechanical) connection can be produced. Moreover, there is the possibility of likewise sealing the intermediate space between the plates.
The seal element can be configured in a variety of different forms. For example, the seal element in the area or on the side of one of the plates can have a cross-sectional shape or area with a flat surface. It is also possible for the seal element to have a cross-sectional area or shape with a tapering surface in the area or on the side of one of the plates. These two possibilities can also be combined with one another such that the seal element on one side of the module has a flat surface and on the other side has a tapering surface. When the modules are stacked on top of one another into a fuel cell arrangement, the tapering surface of the seal element of one module adjoins the flat surface of the seal element in an adjacent module so that relatively good seal action can be achieved.
In another variation, the seal element in the area or one the side of the same plate has a cross-sectional area or shape with a flat surface and a cross-sectional area or shape with a tapering surface. Each cross-sectional area or shape with the flat surface can be separated from the cross-sectional area or shape with the tapering surface by a recess relative to the flat surface. In this embodiment of the seal element, when the modules are stacked on top of one another, the cross-sectional areas or shapes with a flat surface are used as a stop up to which the cross-sectional areas with a tapering surface can be compressed to the maximum degree. The recesses increase the flexibility of the cross-sectional areas or shapes with a tapering surface and hold the material which has been displaced when these cross-sectional areas or shapes are compressed. Thus, relatively simple handling of the modules is possible when stacked on top of one another into a fuel cell arrangement and the seal elements are protected against damage by excessive compression of the cross-sectional areas or shapes with the tapering surface. The seal elements according to this embodiment, when the modules are stacked on top of one another, can interact either with seal elements which are made completely flat or with the similar seal elements. To implement the latter combination, the cross-sectional areas or shapes with the flat surface can be made asymmetrical on either side of the cross-sectional area or shape with the tapering surface so that when two seal elements are stacked on top of one another, the cross-sectional areas or shapes with a tapering surface each adjoin the cross-sectional area or shape with the flat surface of the other seal element at the time and thus two successively connected seal points are formed.
A process for producing a module for a fuel cell arrangement comprises inserting at least areas of at least two plates into a casting mold, and filling the casting mold with a polymer seal material so that the seal material adjoins the two plates. Thus a seal element can be formed relatively efficiently for several plates at the same time, and in the same process step even a mechanical connection between the plates can be produced.
Another aspect of the invention involves a fuel cell arrangement comprising several individual components arranged in a stack. The individual components comprise at least two stacked plates which are at least partially joined to one another by a common seal element of polymer material which is injected onto the plates to form a module.
The foregoing and additional features and characteristics of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawing figures in which like reference numerals designate like elements.
Referring to the cross-sectional view of
To produce the module 10, two plates 7, 8 at a time are inserted into an injection mold with the desired positioning relative to one another at least in the areas in which the seal element 9 is to be formed and are extrusion-coated with a sprayable polymer material. The two plates 7, 8 are joined to one another by the injection mold material by adhesion and/or interlocking. If desired, in this way the abutting area between the two joined plates 7 and 8 can be hermetically sealed. The module 10 which has been produced in this way can be processed as a unit in the assembly of the fuel cell arrangement.
Various other embodiments of the module 10 are shown in
In the embodiment of the module 10 shown in
The embodiment of the module 10 shown in
In
With this execution of the seal element 9, when stacking the individual modules 10 on top of one another into a fuel cell arrangement, one tapering partial cross-section 15 of the seal element 9 at a time adjoins the rectangular partial cross-section 16 and thus the prerequisites for reliable sealing of the modules 10 among one another by the seal elements 9 are good.
In the embodiment of the seal element shown in
The embodiment of the seal element 9 shown in
The embodiment of the seal element 9 which is shown in
If it is deemed advantageous taking into account the cost and benefit, the plates 7, 8 are welded to one another before extrusion coating with the injection molding material or are joined to one another in some other way. This can help achieve a relatively high mechanical load capacity while also maintaining a relatively low contact resistance between the plates 7, 8.
The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.
Number | Date | Country | Kind |
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102 50 434 | Oct 2002 | DE | national |
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6440594 | Kindler et al. | Aug 2002 | B1 |
20030235744 | Pflaesterer | Dec 2003 | A1 |
20040058221 | Chaix | Mar 2004 | A1 |
Number | Date | Country |
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2320647 | Apr 2001 | CA |
2345852 | Nov 2001 | CA |
19910487 | Mar 1999 | DE |
100 28 395 | Dec 2000 | DE |
10028395 | Dec 2000 | DE |
10048871 | Mar 2002 | DE |
0918362 | May 1999 | EP |
0 951 086 | Oct 1999 | EP |
0951086 | Oct 1999 | EP |
1 009 051 | Jun 2000 | EP |
1 032 065 | Aug 2000 | EP |
1032065 | Aug 2000 | EP |
1 098 380 | May 2001 | EP |
1 265 303 | Dec 2002 | EP |
1263068 | Dec 2002 | EP |
1 320 142 | Jun 2003 | EP |
2001-338673 | Dec 2001 | JP |
2001-338673 | Dec 2001 | JP |
WO 9904446 | Jan 1999 | WO |
WO 0180339 | Oct 2001 | WO |
WO 02059995 | Aug 2002 | WO |
03058731 | Jul 2003 | WO |
Number | Date | Country | |
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20040180255 A1 | Sep 2004 | US |