Insulating plate and fuel cell stack for a fuel cell system

Abstract

The present invention relates to an insulating plate (100) for a fuel cell stack (200) of a fuel cell system, the insulating plate (100) comprising: - a main body (101), - a flat seal (103), wherein a groove (105) is formed in the main body (101), wherein the flat seal (103) extends in a first region (107) and in a second region (111) in the groove (105), wherein the flat seal (103) projects with respect to the main body (101) less in the first region (107) than in the second region (111).

Description

[0001] Description

[0002] title

[0003] The presented invention relates to an insulating plate, a fuel cell stack and a manufacturing method for a fuel cell stack for a fuel cell system according to the appended claims.

[0004] State of the art

[0005] For fluid-tight sealing of a fuel cell stack, insulation plates are used at opposite ends of a fuel cell stack, comprising a flat gasket that runs under supply area beads around respective supply areas of polar plates arranged on the insulation plates.

[0006] In addition to the respective supply area ridges, a perimeter ridge runs on a polar plate, which surrounds the polar plate, ie, an active field and the respective supply areas.

[0007] In known insulation plates, when installed in a fuel cell stack, the perimeter bead of an adjacent polar plate rests directly on a base body, i.e., without contact with a seal.

[0008] However, since the perimeter bead of a subsequent first fuel cell must seal the fuel cell, it is necessary to compress this fuel cell so strongly that its perimeter bead is deformed.

[0009] The sealing effect or surface pressure distribution between a

[0010] The supply area bead and the perimeter bead must be maintained over the lifetime of a fuel cell system, even if a corresponding flat gasket, which is an elastomer, relaxes.

[0011] To ensure such a sealing effect, a polar plate is usually pressed so strongly that it deforms, i.e. bends around a respective flat gasket

[0012] Disclosure of the invention

[0013] Within the scope of the invention presented, an insulating plate, a fuel cell stack, and a manufacturing method for producing the fuel cell stack are presented. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the insulating plate according to the invention naturally also apply in connection with the fuel cell stack according to the invention or the manufacturing method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0014] The invention presented serves in particular to provide a robust fuel cell system.

[0015] Thus, according to a first aspect of the invention presented, an insulating plate for a fuel cell stack of a fuel cell system is presented.

[0016] The proposed insulation panel comprises a base body and a flat gasket, wherein a groove is formed in the base body, wherein the flat gasket extends in the groove in a first region and in a second region, and wherein the flat gasket protrudes less from the base body in the first region than in the second region. In the context of the proposed invention, a protrusion or projection of the flat gasket from the base body is understood to mean an area by which the flat gasket is higher than the base body.

[0017] The insulation plate presented here comprises a base body made of an electrically insulating material, such as plastic, and has a groove or channel in which a flat gasket extends. The base body is, for example, pressure-resistant, whereas the flat gasket is elastic and consists of, for example, an elastomer.

[0018] Of course, the groove can comprise several sections that run separately from one another or are connected to one another.

[0019] Accordingly, the flat gasket can comprise several sections that run separately from one another or are connected to one another. This means that the flat gasket can be designed as a single piece or in multiple parts.

[0020] The presented invention is based on the principle of using an insulating plate comprising a flat gasket that protrudes less from the base body in a first region than in a second region. Accordingly, the arrangement of the flat gasket distributes the contact pressure between a polar plate and the insulating plate in a fuel cell stack such that the contact pressure differs between the first and second regions.

[0021] It can be provided that the flat seal runs in such a way that it supports a perimeter bead and respective supply area beads of a polar plate arranged adjacent to the insulating plate.

[0022] Since the flat gasket protrudes less from the base body in the first region than in the second region, the first region requires less contact pressure than the second region, thus preventing deformation of a polar plate pressed onto the insulating plate in the first region. Furthermore, the first region can comprise several subregions that extend in the head region of the insulating plate into an area that surrounds only one active field of a polar plate arranged on the insulating plate.

[0023] Through a first region, which comprises several sub-regions that extend in the head region of the insulating plate in an area that only surrounds an active field of a polar plate arranged on the insulating plate, i.e., which does not surround any areas in which supply areas or so-called "ports" for conducting operating media are arranged, a perimeter bead of a respective polar plate arranged on the insulating plate is supported in the first region or the sub-regions directly on the base body of the insulating plate and in the second region on the flat gasket. The flat gasket compensates for movement-related height differences between the base body and the polar plate and acts as a fluid-tight seal.

[0024] It can further be provided that the groove is deeper in the first region than in the second region.

[0025] By creating a groove that is deeper in the first area than in the second area, the height or projection of the flat gasket relative to the base body can be adjusted without adjusting the height of the flat gasket itself. This means that the flat gasket can have a constant height or be the same height in the first area and the second area.

[0026] It can further be provided that the groove is deeper in the first region than in the second region by an amount by which the flat seal projects beyond the base body in the second region.

[0027] By means of a groove which is deeper in the first region than in the second region by an amount by which the flat gasket protrudes in the second region relative to the base body, the flat gasket is embedded in the base body in the first region in such a way that a perimeter bead of a polar plate arranged on the insulating plate presses onto the base body or is supported by the base body or is not subjected to greater contact pressure by the flat gasket in the region of the flat gasket than by the base body.

[0028] It can further be provided that the flat seal is less high in the first area than in the second area.

[0029] By having a less high structure of the flat gasket in the first area relative to the second area, which can be achieved, for example, by a flat gasket of different thickness, the contact pressure caused by the flat gasket on a perimeter bead of a polar plate arranged on the insulating plate is reduced in the first area compared to the second area.

[0030] In particular, the flat seal in the first area can run flush with or to the base body.

[0031] It can further be provided that a transition from the first region to the second region of the flat seal and / or the groove is wedge-shaped.

[0032] A wedge-shaped or smooth transition between the first and second regions ensures a smooth increase in contact pressure on a perimeter bead of a polar plate arranged on the insulation plate from the first region to the second region. This ensures a fluid-tight arrangement of a polar plate on the insulation plate.

[0033] It can also be provided that the flat seal surrounds at least three sides of the insulating plate.

[0034] To surround three sides of the insulation panel, the flat gasket can, for example, comprise a perimeter part or an edge sealing element that surrounds the three sides and, for example, follows the contour of a perimeter bead of a polar plate arranged on the insulation panel. Accordingly, the flat gasket can comprise an edge sealing element and a supply area sealing element that follows the contour of a supply area bead of the polar plate. The edge sealing element and the supply area sealing element can run separately or be connected to one another.

[0035] Accordingly, it can be provided that the flat seal is formed in one piece or in several parts or comprises a plurality of separate sealing elements.

[0036] A multi-part flat gasket can be particularly easily inserted into the groove of the base body of the insulation panel in several parts or steps.

[0037] It can further be provided that the flat seal comprises an edge sealing element surrounding at least three sides of the insulating plate and a supply area sealing element surrounding at least one supply area formed in the base body.

[0038] The supply area sealing element can in particular be designed such that it surrounds all supply areas formed in the base body of the insulating plate.

[0039] The supply sealing element can be connected to the edge sealing element, for example, via a number of connecting webs or can be designed completely separately from the edge sealing element.

[0040] According to a second aspect, the presented invention relates to a fuel cell stack for a fuel cell system, wherein the fuel cell stack comprises a number of possible embodiments of the presented insulating plate and a number of polar plates, each comprising a perimeter bead formed circumferentially around the polar plate and a number of supply area beads formed circumferentially around respective supply areas, wherein a polar plate adjacent to a respective insulating plate is supported with its perimeter bead in the first area on the base body and in the second area on the flat gasket of the insulating plate, and is supported with its respective supply area beads on the flat gasket of the insulating plate. The presented insulating plate serves in particular to provide the presented fuel cell stack.

[0041] According to a third aspect, the presented invention relates to a manufacturing method for producing a fuel cell stack for a fuel cell system.

[0042] The proposed manufacturing method comprises the pressing of a polar plate, which comprises a perimeter bead formed circumferentially around the polar plate and a number of supply area beads formed circumferentially around respective supply areas, with a possible design of the proposed insulating plate such that the polar plate is supported with its perimeter bead in the first area on the base body and in the second area on the flat gasket of the insulating plate, and is supported with its respective supply beads on the flat gasket of the insulating plate.

[0043] The presented manufacturing process is used in particular for the production of the presented fuel cell stack.

[0044] Advantages described in detail with respect to the insulating plate for a fuel cell stack of a fuel cell system according to the first aspect of the invention equally apply to the fuel cell stack for a fuel cell system according to the second aspect of the invention and the manufacturing method for manufacturing a fuel cell stack for a fuel cell system according to the third aspect of the invention.

[0045] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.

[0046] Shown are: Figure 1 a schematic representation of a possible design of the presented insulation panel,

[0047] Figure 2 is a detailed view of the insulation plate according to Figure 1,

[0048] Figure 3 shows a possible embodiment of the presented manufacturing process for producing the presented fuel cell stack.

[0049] Figure 1 shows an insulating plate 100 for a fuel cell stack of a fuel cell system in a plan view.

[0050] The insulating plate 100 comprises a base body 101 and a flat seal 103.

[0051] The flat seal 103 runs in a groove 105 formed in the base body 101 and in a first region 107, as indicated by arrows 109, and in a second region 111, as indicated by arrows 113.

[0052] In the present case, the first region 107 extends over a zone in which no supply regions 115 for conducting operating media are formed. In particular, the first region 107 can be provided to superimpose an active field on a polar plate arranged adjacent to the insulating plate 100.

[0053] In the present case, the second region 111 extends over a zone in which the supply regions 115 are formed. In particular, the second region 111 can be provided to overlie respective supply regions of a polar plate arranged adjacent to the insulating plate 100.

[0054] The flat gasket 103 comprises an edge sealing element 117, which is formed circumferentially around the insulating plate 100 on three sides, and a supply area sealing element 119, which borders the supply areas 115.

[0055] For easy positioning of the flat seal 103 in the groove 105, the

[0056] Edge sealing element 117 and the supply area sealing element 119 are connected via connecting elements 121, so that the flat seal 103 can be introduced into the useful area 105 as a preconfigured sealing element.

[0057] Looking at Figure 2, which shows the insulating plate 100 in cross-section, it can be seen that the flat seal 103 protrudes less from the base body 101 in the first region 107 than in the second region 111. This is achieved, for example, by the groove 105 being deeper in the first region 107 than in the second region 111.

[0058] Furthermore, Figure 2 shows that the flat gasket 103 changes its profile in a wedge-shaped or uniform manner between the first region 107 and the second region 111, so that a contact pressure exerted by the flat gasket 103 on a polar plate arranged adjacent to the insulating plate 100 changes uniformly in a manner analogous to the height profile of the flat gasket 103. Accordingly, less pressure acts on the polar plate in the first region 107 than in the second region 111, so that the polar plate is relieved in the first region 107 and protected from deformation.

[0059] The first region 107 is, for example, between 10 mm and 20 mm long or wide. The groove 105 is, for example, between 1.8 mm and 2 mm deep at its deepest point in the first region 107 and 1.6 mm deep in the second region.

[0060] In the second area 111, the flat seal 103 protrudes 0.4 mm from the base body 101, as indicated by arrow 123.

[0061] Figure 3 illustrates a manufacturing method 300 for producing a fuel cell stack 200. For this purpose, a polar plate 201 is pressed onto the insulating plate 100 according to Figure 1 or Figure 2, as indicated by arrow 301.

[0062] The polar plate 201 is aligned such that a perimeter bead 203 and, if applicable, a supply area bead of the polar plate 201 are pressed onto the flat gasket 103.

Claims

Claims 1 . Insulating plate (100) for a fuel cell stack (200) of a fuel cell system, the insulating plate (100) comprising: a base body (101), a flat seal (103), a groove (105) being formed in the base body (101), the flat seal (103) running in a first region (107) and in a second region (111) in the groove (105), the flat seal (103) projecting less from the base body (101) in the first region (107) than in the second region (111).

2. Insulating plate (100) according to one of the preceding claims, characterized in that the flat seal (103) extends in such a way that it supports a perimeter bead and respective supply area beads of a polar plate (201) arranged adjacent to the insulating plate.

3. Insulating plate (100) according to one of the preceding claims, characterized in that the first region (107) comprises a plurality of partial regions which extend in the head region of the insulating plate (100) in a region which surrounds only an active field of a polar plate (201) arranged adjacent to the insulating plate (100).

4. Insulating plate (100) according to one of the preceding claims, characterized in that in the first region (107) the groove (105) is formed deeper than in the second region (111).

5. Insulating plate (100) according to claim 4, characterized in that the groove (105) in the first region (107) is deeper than in the second region (111) by an amount by which the flat seal (103) projects beyond the base body (101) in the second region (111).

6. Insulating plate (100) according to one of claims 1 to 4, characterized in that in the first region (107) the flat seal (103) is less high than in the second region (111).

7. Insulating plate (100) according to one of the preceding claims, characterized in that a transition from the first region (107) to the second region (111) of the flat seal (103) and / or the groove (105) is wedge-shaped.

8. Insulating plate (100) according to one of the preceding claims, characterized in that the flat seal (103) surrounds at least three sides of the insulating plate (100).

9. Insulating plate (100) according to one of the preceding claims, characterized in that the flat seal (103) is formed in one piece.

10. Insulating plate (100) according to one of the preceding claims, characterized in that the flat seal (103) comprises a plurality of separate sealing elements (117, 119).

11. Insulating plate (100) according to claim 10, characterized in that the flat seal (103) comprises an edge sealing element (117) surrounding at least three sides of the insulating plate (100) and a supply area sealing element (119) surrounding at least one supply area (115) formed in the base body (101).

12. A fuel cell stack (200) for a fuel cell system, the fuel cell stack (200) comprising: a number of insulating plates (100) according to any one of claims 1 to 11, a number of polar plates (201), each comprising a perimeter bead (203) formed circumferentially around the polar plate (201) and a number of supply area beads formed circumferentially around respective supply areas, wherein a polar plate (201) adjacent to a respective insulating plate (100) is supported with its perimeter bead (203) in the first area (107) on the base body (101) and in the second area (111) on the flat gasket (103) of the insulating plate (100), and is supported with its respective supply area beads on the flat gasket (103) of the insulating plate (100).

13. Manufacturing method (300) for producing a fuel cell stack (200) for a fuel cell system, wherein the manufacturing method (300) comprises: Pressing a polar plate (201) which has a circumferentially surrounding the polar plate (201) formed perimeter bead (203) and a number of supply area beads formed circumferentially around respective supply areas, with an insulating plate (100) according to one of claims 1 to 11 such that the polar plate (201) is supported with its perimeter bead (203) in the first area (107) on the base body (101) and in the second area (111) on the flat seal (103) of the insulating plate (100), and is supported with its respective supply beads on the flat seal (103) of the insulating plate (100).

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