Cell stack and its manufacture

Abstract

The presented invention relates to a cell stack (100) for distributing media in a system (101), the cell stack (100) comprising: a plurality of media distribution plates (103a, 103b, 103c, 301, 303); and a plurality of intermediate layers (105a, 105b, 105c, 105d), each intermediate layer (105a, 105b, 105c, 105d) containing two media distribution plates (103a, 103b, 103c, 301, 303). The media distribution stack (100) includes a plurality of media distribution plates (103a, 103b, 103c, 301, 303) disposed between the media distribution plates (103a, 103b, 103c, 301, 303) to electrically insulate the media distribution plates from one another, and at least each media distribution plate (103a, 103b, 103c, 301, 303) is disposed in alignment with one another in the cell stack (100), whereby an outer edge (109) of the media distribution stack (100) is formed by the edges of each of at least the media distribution plates (103a, 103b, 103c, 301, 303). The present invention further relates to a method (200) of manufacturing the media distribution stack (100).

Description

[Technical field]

[0001] In cell stacks, such as those found in fuel cells or electrolysers, cells are stacked together to increase the available voltage or to increase the media throughput. Such cells consist of alternating active components (often called "MEA" membrane electrode unit in fuel cell stacks) and media distribution plates (also called bipolar plates in fuel cells), which may consist of further components. [Background technology]

[0002] For cost and space-saving reasons, it is advantageous to minimize the material thickness of each media distribution plate, which may lead to deformation of the edges of the media distribution plates during the manufacturing process, transportation, or installation in the final system, which may in extreme cases lead to adjacent media distribution plates touching each other and creating a short circuit in the media distribution plate stack.

[0003] It is known that respective insulating intermediate layers, for example so-called "subgaskets" or edge reinforcements, protrude beyond the respective media distribution plates of a cell stack so that short circuits cannot occur even if the edges of the media distribution plates are distorted. Summary of the Invention

[0004] Within the scope of the presented invention, a cell stack and a manufacturing method are presented having the features of the respective independent claims. Further features and details of the invention emerge from the respective dependent claims, the following description and the drawings. In that case, the features and details described in the context of the cell stack according to the invention naturally also apply in the context of the manufacturing method according to the invention and vice versa, respectively, whereby they are always mutually referred to or can be referred to in the disclosure of the individual inventive aspects.

[0005] The presented invention is particularly useful for providing a compact and robust cell stack.In particular, the presented invention is particularly useful for providing a compact and robust fuel cell stack.

[0006] Thus, in a first aspect of the presented invention, a cell stack for distributing media in a system is presented, the cell stack comprising a number of media distribution plates and a number of intermediate layers, each intermediate layer being arranged between two media distribution plates and electrically insulating the media distribution plates from one another, and at least each media distribution plate being arranged in alignment with one another in the cell stack, whereby an outer edge of the media distribution stack is formed by at least each edge of the media distribution plates.

[0007] In the context of the presented invention, a media distribution plate is to be understood as a flat structure for conducting at least one medium, such as for example hydrogen, in a system, such as for example a fuel cell.

[0008] In the context of the presented invention, an intermediate layer is to be understood as an electrically insulating layer arranged between two media distribution plates, such as, for example, the so-called "active layer" of a fuel cell system.

[0009] The proposed cell stack is based on alternating stacked media distribution plates and intermediate layers, where at least the media distribution plates are arranged in line with one another, so that the respective particularly rigid edges of the media distribution plates form the edges of the proposed cell stack.

[0010] Due to the fact that the edges of the proposed cell stack are at least partially formed by the media distribution plate, the edges of the cell stack are particularly stiff and therefore loadable, which means that the cell stack is very robust against deformations and can therefore be easily introduced into the target system, e.g. a fuel cell system, and aligned at the edges.

[0011] In particular, the proposed cell stack design allows the individual layers to be stacked along alignment rails or the like without the risk of short circuits being increased, and in addition, the proposed cell stack design avoids damage when the cell stacks are pressed into the respective housings.

[0012] It may be envisaged that the media distribution plates are arranged in alignment with each other and with the intermediate layer of the presented cell stack, so that the media distribution plates and the intermediate layer together form the edge of the cell stack.

[0013] An insulating layer, e.g. a plastic layer, provided on each media distribution plate prevents electrical shorts between the respective contacting media distribution plates when two media distribution plates come into contact, which may occur, for example, due to bending of one or more media distribution plates.

[0014] Furthermore, it may be provided that each media distribution plate is surrounded on its edge on the anode side and / or at least on its outer edge on the cathode side with an electrically insulating layer.

[0015] The insulating layer can be arranged circumferentially or partially on the respective media distribution plate, but always surrounds the border region, i.e. the outer edge of the respective media distribution plate which forms the edge of the presented cell stack.

[0016] It may further be envisaged that each media distribution plate comprises a first plate and a second plate arranged opposite the first plate, and that burrs formed on the respective edges of the first plate and / or the second plate point towards the respective oppositely located plate.

[0017] During the manufacture of the media distribution plate, cutting edges or burrs can occur which can quickly lead to severe damage if they come into contact with structures such as, for example, a plastic insulating layer. Burrs on some of the media distribution plates pointing towards each other, i.e. towards the respective plates located opposite, can prevent the burrs from damaging structures adjacent to or surrounding the media distribution plate, such as, for example, an insulating layer.

[0018] It can further be envisaged that the at least one media distribution plate comprises a first plate and a second plate arranged opposite the first plate, the first plate and / or the second plate comprising at least one groove, each extending in the direction of the adjacently arranged media distribution plate, such that in the event of deformation of the at least one media distribution plate, it first comes into contact with the adjacently arranged media distribution plate and prevents other parts of the at least one media distribution plate from coming into contact with the adjacently arranged media distribution plate.

[0019] Grooves, such as material protrusions or ridges of the substrate, especially ridges in the material forming the plate of the media distribution plate, serve as buffer zones that, in the event of deformation of the media distribution plate, first come into contact with the respective structures adjacent to the media distribution plate and absorb the kinetic energy of the media distribution plate movement, by absorbing the kinetic energy in the grooves, limiting the movement of the media plate itself and avoiding contact, in particular, of the areas of the media distribution plate where voltage is present with the adjacent structures.

[0020] The grooves are disposed in each media distribution plate and may for example consist of a flexible material or may be made of the material itself forming the media distribution plate.

[0021] It may further be contemplated that the cell stack may be configured to distribute media in systems such as the following list of systems: fuel cell systems, electrolyzers, and redox flow systems.

[0022] The presented cell stack is suitable for use in any electrochemical unit where stacking of self-conducting electrically conducting components with insulating intermediate layers is problematic, such as for example PEM fuel cell systems.

[0023] In a second aspect, the presented invention relates to a manufacturing method for manufacturing possible embodiments of the presented cell stack. The presented manufacturing method includes an arrangement step of interleaving respective media distribution plates of a plurality of media distribution cells with respective intermediate layers of a plurality of intermediate layers. Furthermore, the presented manufacturing method includes an alignment step of at least aligning the media distribution plates, whereby the respective media distribution plates are arranged in line with each other in the cell stack, and an outer edge of the cell stack is formed by at least respective edges of the media distribution plates.

[0024] The alignment step envisaged by the invention makes the placement step much less susceptible to stacking defects, known for example from edge reinforcements being pushed in or collapsed in prior art manufacturing methods. Furthermore, when carrying out the proposed manufacturing method, the media distribution plate and intermediate layers can be stacked more precisely and more cheaply than in prior art manufacturing methods, since the individual layers of the media distribution plate can be mechanically applied to the alignment elements.

[0025] The manufacturing method may further contemplate including an insulating step of surrounding each media distribution plate on at least one outer edge with an electrically insulating layer.

[0026] The electrically insulating layer can be, for example, a plastic or a wax. For example, prior to the positioning step of the proposed manufacturing method, each media distribution plate can be at least partially placed in a bath of liquid electrically insulating material, which can then be cured. Alternatively, after the positioning step, an electrical insulator can be placed on each media distribution plate, for example by being covered.

[0027] Further, the manufacturing method may include a providing step for providing a media distribution plate, in which the edges of each media distribution plate are punched out without burrs by precision punching, or each burr generated in the punching process is removed, or each burr generated in the punching process is deformed and shaped, so that the burrs of each plate of the media distribution plate point toward the plate located opposite the media distribution plate, respectively, by punching, or in a cutting process, the cutting burr direction is selected so that the burrs of each plate of the media distribution plate point toward the plate located opposite the media distribution plate, respectively.

[0028] A geometry without cutting edges or without burrs of the respective media distribution plates is useful, in particular to prevent damage to the electrical insulation layer applied to the respective media distribution plate. The deburring of the respective media distribution plates can be carried out during the stamping process for stamping the media distribution plates out of the metal sheet or in a separate step thereafter. In particular, the respective edges or burrs of the plates of the media distribution plates can be deformed after the stamping process so as to point towards the plates of the media distribution plates arranged opposite them and thus away from the insulation layer applied to the media distribution plates.

[0029] Other advantages, features and details of the invention will become apparent from the following description in which examples of the invention are described in detail with reference to the drawings, in which the features mentioned in the claims and in the description can each individually contribute to the embodiment of the invention presented or in any combination. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 shows a possible embodiment of a cell stack as presented. [Diagram 2] FIG. 1 shows a possible embodiment of the proposed manufacturing method. [Diagram 3] 1A-1C are detailed views of various embodiments of a media distribution plate according to possible embodiments of the presented cell stack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] A cell stack 100 is shown in Figure 1. The cell stack 100 is part of a system 101, such as a fuel cell system.

[0032] The cell stack 100 comprises a number of media distribution plates 103a, 103b and 103c and a number of intermediate layers 105a, 105b, 105c and 105d.

[0033] The media distribution plates 103a, 103b and 103c are surrounded by electrical insulators 107 at their respective ends.

[0034] Media distribution plates 103a, 103b and 103c are aligned with one another in accordance with the present invention such that edges 109 of cell stack 100 are formed by the respective ends of media distribution plates 103a, 103b and 103c.

[0035] Here, the media distribution plate 103b is deformed by a mechanical impact, whereby one end of the media distribution plate 103b is pushed against the media distribution plate 103 a Press one end of the media distribution plate 103b and 103 a The presence of electrical insulator 107 between media distribution plates 103b and 103 a Even if the media distribution plates 103b and 103 aNo current can flow between them, thereby avoiding short circuits.

[0036] In FIG. 2, a manufacturing method 200 for manufacturing a possible embodiment of the presented cell stack, for example cell stack 100, is shown.

[0037] The manufacturing method 200 includes an arrangement step 201 for respectively interleaving a media distribution plate of each of a plurality of media distribution cells with a respective intermediate layer of a plurality of intermediate layers.

[0038] Additionally, the presented manufacturing method includes an alignment step 203 for aligning at least the media distribution plates, whereby each media distribution plate is positioned in alignment with each other in the cell stack, and at least the respective edges of the media distribution plates form the outer edges of the cell stack.

[0039] To align the media distribution plates, the cell stack can repeatedly hit the stop elements, for example when placing an additional media distribution plate on the cell stack or when placing the last media distribution plate respectively.

[0040] In FIG. 3, media distribution plate 301 and media distribution plate 303 are shown.

[0041] The media distribution plate 301 comprises a first plate 301a and a second plate 301b. The first plate 301a has an edge bent towards the second plate 301b, so that the burrs 305 of the first plate 301a enter into the receiving portions 307 of the second plate 301b and the periphery is accordingly protected against the burrs 305.

[0042] In particular, by disposing the burrs 305 in the receiving portions 307, it is possible to prevent the burrs 305 from damaging the electrical insulators covering the first plate 301a and the second plate 301b.

[0043] The media distribution plate 303 comprises a first plate 303a and a second plate 303b. The first plate 303a comprises a groove 309 that rises above a base region 311 of the first plate 303a. The groove 309 is thus angled outwardly and away from the second plate 303b.

[0044] The curvature of the grooves 309 ensures that when the media distribution plate 303 moves, the grooves 309 first collide with the respective structures arranged around the media distribution plate 303, reducing the kinetic energy stored in the media distribution plate. Contact between the base region 311 and the respective structures is accordingly avoided. Thus, the burr 313 of the first plate 303a is protected by the grooves 309 against contact with other structures, and can be bent away from the second plate 303b.

[0045] Similar to groove 309 , the second plate 303 b includes a groove 315 that protects a base region 317 of the second plate 303 b against contact with structures at the periphery of the media distribution plate 303 . [Explanation of symbols]

[0046] 100 Cell Stack 101 System 103a, 103b, 103c media distribution plate 105a, 105b, 105c, 105d Intermediate layers 107 Electrical insulation layer 109 Edge 200 Manufacturing method 201 Placement Step 203 Alignment Step 301 Media Distribution Plate 301a First Plate 301b Second Plate 303 Media Distribution Plate 303a First Plate 303b Second Plate 305 Bali 307 Storage Unit 309 Groove 311 Base Area 313 Bali 315 Groove 317 Base Area

Claims

1. A cell stack (100) for distributing a medium in a system (101), the cell stack (100) comprising: - a number of media distribution plates (103a, 103b, 103c, 301, 303); a number of intermediate layers (105a, 105b, 105c, 105d), Each intermediate layer (105a, 105b, 105c, 105d) is disposed between two media distribution plates (103a, 103b, 103c, 301, 303) and electrically insulates said media distribution plates from each other; at least said media distribution plates (103a, 103b, 103c, 301, 303) are aligned with one another in said cell stack (100), whereby an outer edge (109) of said cell stack (100) is formed by the edges of at least each of said media distribution plates (103a, 103b, 103c, 301, 303); Each media distribution plate (103a, 103b, 103c, 301, 303) comprises a first plate (301a, 303a) and a second plate (301b, 303b) arranged opposite the first plate, A cell stack, wherein a burr formed on each edge of the first plate (301a, 303a) and / or the second plate (301b, 303b) points towards the respective opposite plate.

2. 2. The cell stack (100) of claim 1, characterized in that each media distribution plate (103a, 103b, 103c, 301, 303) is surrounded on at least one outer edge by an electrical insulating layer (107).

3. 3. The cell stack (100) according to claim 2, characterized in that each media distribution plate (103a, 103b, 103c, 301, 303) is surrounded by said electrical insulation layer (107) at least on said outer edge on the anode side and / or on the cathode side.

4. Each media distribution plate (103a, 103b, 103c, 301, 303) comprises a first plate (301a, 303a) and a second plate (301b, 303b) arranged opposite the first plate (301a, 303a); The second plate (301b) has a receiving portion (307) for receiving a burr (313) of the first plate (301a); A cell stack (100) according to any one of claims 1 to 3, characterized in that the first plate (301a) is arranged offset relative to the second plate (301b) and the burr (313) of the first plate (303a) is introduced into the receiving portion (307) of the second plate (301b).

5. A cell stack (100) for distributing a medium in a system (101), the cell stack (100) comprising: - a number of media distribution plates (103a, 103b, 103c, 301, 303); a number of intermediate layers (105a, 105b, 105c, 105d), Each intermediate layer (105a, 105b, 105c, 105d) is disposed between two media distribution plates (103a, 103b, 103c, 301, 303) and electrically insulates said media distribution plates from each other; at least said media distribution plates (103a, 103b, 103c, 301, 303) are aligned with one another in said cell stack (100), whereby an outer edge (109) of said cell stack (100) is formed by the edges of at least each of said media distribution plates (103a, 103b, 103c, 301, 303); Each media distribution plate (103a, 103b, 103c, 301, 303) comprises a first plate (301a, 303a) and a second plate (301b, 303b) arranged opposite the first plate (301a, 303a); The second plate (301b) has a receiving portion (307) for receiving a burr (313) of the first plate (301a); A cell stack, wherein the first plate (301a) is offset relative to the second plate (301b), and the burr (313) of the first plate (303a) is introduced into the receiving portion (307) of the second plate (301b).

6. At least one media distribution plate (103a, 103b, 103c, 301, 303) comprises a first plate (301a, 303a) and a second plate (301b, 303b) arranged opposite said first plate (301a, 303a); The first plate (301a, 303a) and / or the second plate (301b, 303b) are provided with at least one groove (309, 315), which extends in the direction of the respective adjacent media distribution plate (103a, 103b, 103c, 301, 303) and prevents the adjacent media distribution plate (103a, 103b, 103c, 301, 303) from deforming when the at least one media distribution plate (103a, 103b, 103c, 301, 303) is deformed.

6. The cell stack (100) according to claim 1, characterized in that at least one of the at least one media distribution plate (103a, 103b, 103c, 301, 303) first contacts a media distribution plate (103a, 103b, 103c, 301, 303) disposed adjacent thereto, thereby preventing other parts of the at least one media distribution plate (103a, 103b, 103c, 301, 303) from contacting the adjacently disposed media distribution plate (103a, 103b, 103c, 301, 303).

7. A cell stack (100) for distributing a medium in a system (101), the cell stack (100) comprising: - a number of media distribution plates (103a, 103b, 103c, 301, 303); a number of intermediate layers (105a, 105b, 105c, 105d), Each intermediate layer (105a, 105b, 105c, 105d) is disposed between two media distribution plates (103a, 103b, 103c, 301, 303) and electrically insulates said media distribution plates from each other; at least said media distribution plates (103a, 103b, 103c, 301, 303) are aligned with one another in said cell stack (100), whereby an outer edge (109) of said cell stack (100) is formed by the edges of at least each of said media distribution plates (103a, 103b, 103c, 301, 303); At least one media distribution plate (103a, 103b, 103c, 301, 303) comprises a first plate (301a, 303a) and a second plate (301b, 303b) arranged opposite said first plate (301a, 303a); a first plate (301a, 303a) and / or a second plate (301b, 303b) each having at least one groove (309, 315) extending in the direction of a respective adjacent media distribution plate (103a, 103b, 103c, 301, 303) and configured such that, in the event of deformation of the at least one media distribution plate (103a, 103b, 103c, 301, 303), the at least one media distribution plate (103a, 103b, 103c, 301, 303) first comes into contact with the adjacent media distribution plate (103a, 103b, 103c, 301, 303) and prevents other parts of the at least one media distribution plate (103a, 103b, 103c, 301, 303) from coming into contact with the adjacent media distribution plate (103a, 103b, 103c, 301, 303).

8. The cell stack (100) according to any one of claims 1 to 7, characterized in that the cell stack (100) is configured to distribute a medium in a system (101) from the following list of systems: a fuel cell system, an electrolyzer, and a redox flow system.

9. A manufacturing method (200) for manufacturing a cell stack (100) according to any one of claims 1 to 8, comprising the steps of: The manufacturing method (200) comprises: - interleaving (201) each media distribution plate (103a, 103b, 103c, 301, 303) of the plurality of media distribution plates (103a, 103b, 103c, 301, 303) with each intermediate layer of the plurality of intermediate layers (105a, 105b, 105c, 105d); - aligning (203) the media distribution plates (103a, 103b, 103c, 301, 303) whereby the respective media distribution plates (103a, 103b, 103c, 301, 303) are aligned with each other in the cell stack, and an outer edge of the cell stack (100) is formed by at least the edges of each of the media distribution plates (103a, 103b, 103c, 301, 303).

10. The manufacturing method (200) comprises: A method according to claim 9, characterized in that it further comprises surrounding each media distribution plate (103a, 103b, 103c, 301, 303) on at least one outer edge with an electrical insulating layer (107).

11. The manufacturing method (200) comprises: - the edges of each media distribution plate (103a, 103b, 103c, 301, 303) are punched out without burrs by precision punching, or each burr (305) generated during the punching process is removed after the punching process, or each burr (305) generated during the punching process is molded after the punching process, so that the burrs (305) of each plate (301a) of the media distribution plate (301) face each of the media distribution plates (301); 11. The method according to claim 9 or 10, further comprising providing the media distribution plates (103a, 103b, 103c, 301, 303) by punching or in a cutting process, the cutting burr direction being selected such that a burr (305) of a respective plate (301a) of the media distribution plate (301) points towards the plate (301b) located respectively opposite the media distribution plate (301).

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