Method for manufacturing a membrane assembly for a fuel cell

Abstract

Method for manufacturing a membrane arrangement (1) for a fuel cell, wherein the membrane arrangement (1) is formed from at least a frame element (5), a membrane (2) surrounding the edge of the frame element (5) and a seal (11 to 14), wherein the seal (11 to 14) is applied to the frame element (5), characterized in that one or more further layers (18 to 21) are arranged between the frame element (5) and the seal (11 to 14).

Description

[0001] The invention relates to a method for manufacturing a membrane arrangement for a fuel cell.

[0002] US Patent 7,138,201 B2 discloses a method for manufacturing a fuel cell. In this method, a seal is formed from a liquid thermoset sealing material, and a stack of separators and a membrane electrode assembly are tightly connected by means of the seal. The seal is created by introducing the liquid thermoset sealing material into gaps located between each separator and the membrane electrode assembly. The thermoset sealing material is made of a silicone-containing elastomer or an isobutylene-containing elastomer.

[0003] From DE 10 2006 004 748 A1, a membrane electrode assembly with a multi-component sealing rim is known, wherein the rim components are joined using two different joining methods. The rim structure of the membrane electrode assembly comprises at least two materials (sealing material A and frame B) which are joined to each other by material bonding and by form bonding. The frame B has at least one perforation through which the sealing material penetrates and creates an interlocking connection. Adhesive bonding, laminating, and / or injection molding processes are suitable for manufacturing the multi-component rim and the corresponding membrane electrode assembly.

[0004] US 2010 / 0248087 A1 discloses a method for manufacturing an electrode-membrane frame assembly, the main part of which is formed in particular by applying a first catalyst layer to one of the surfaces of an electrolyte membrane, arranging a first gas diffusion layer on the surface of the first catalyst layer and within the circumferential region of the electrolyte membrane, and furthermore by applying a second catalyst layer to the other surface of the electrolyte membrane and arranging a second gas diffusion layer on the surface of the second catalyst layer and within the circumferential region of the electrolyte membrane such that the position of the outer circumference of the second gas diffusion layer differs from that of the outer circumference of the first gas diffusion layer.

[0005] DE 101 52 192 B4 discloses a method for producing a carrier seal for sealing two parallel counter surfaces, in particular for sealing the reactants in a fuel cell, in which a sheet-shaped carrier element is placed in a frame and stretched in a plane, the carrier element has a circumferential sealing area on at least one surface, on which a non-polymerized sealing material is applied and subsequently the applied sealing material is formed and polymerized in a vulcanization tool.

[0006] The invention is based on the objective of providing a method for manufacturing a membrane arrangement for a fuel cell that is improved compared to the prior art.

[0007] The problem is solved according to the invention by a method which has the features specified in claim 1.

[0008] Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] In the method for manufacturing a membrane assembly for a fuel cell, the membrane assembly is formed according to the invention from at least a frame element, a membrane surrounded at its edge by the frame element, and a seal, wherein the seal is applied to the frame element. One or more further layers are arranged between the frame element and the seal.

[0010] The seal is specifically designed to seal the membrane assembly to one or more bipolar plates. Due to the application of the seal to the frame element according to the invention, preferably on both sides, high temperature effects on the membrane, long process times, long residence times within a tool during manufacturing, and influences from manufacturing tolerances of input components during the production of a fuel cell are avoided. High scrap costs due to defective seals are also avoided if the process step of applying the seal takes place at the end of a process chain in the production of the fuel cell. Furthermore, it is particularly advantageous to be able to design a flexible seal geometry, use metallic and graphitic bipolar plates, and distribute the process steps in the production of the membrane assembly and the fuel cell across individual stations.to disentangle. In addition, the use of the method according to the invention advantageously results in the process steps being easier to control as individual steps, resulting in lower process costs and allowing for different options for applying the seal.

[0011] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0012] This shows: Fig. 1 schematically a membrane arrangement which is tightly arranged between two bipolar plates, Fig. Figures 2A to 2C schematically show different steps of a first embodiment of a method according to the invention for producing the membrane arrangement according to Fig. 1, Fig. Figures 3A to 3C schematically show different steps of a second embodiment of a method according to the invention for producing the membrane arrangement according to Fig. 1, Fig. Figures 4A to 4C schematically show different steps of a third embodiment of a method according to the invention for producing the membrane arrangement according to Fig. 1, Fig. Figures 5A to 5D schematically show different steps of a fourth embodiment of a method according to the invention for producing the membrane arrangement according to Fig. 1 and Fig. 6 schematically different steps of a fifth embodiment of a method according to the invention for producing the membrane arrangement according to Fig. 1.

[0013] Corresponding parts are marked with the same reference symbols in all figures.

[0014] In Fig. Figure 1 shows a membrane arrangement 1 for a fuel cell. The membrane arrangement 1 comprises a membrane 2, in particular an electrolyte membrane, which has a catalyst layer 3, 4 on both sides.

[0015] Furthermore, the membrane arrangement 1 comprises a frame element 5. The frame element 5 has a cutout surface 5.1, which is completely surrounded by a frame area 5.2. In the illustrated embodiment, the frame element 5 is designed as a complete frame. Alternatively, the frame element 5 is designed as a partial frame (not shown).

[0016] In the illustrated embodiment, the catalyst layer 3 is bonded to the frame area 5.2 of the frame element 5, with an adhesive 6 being introduced between the catalyst layer 3 and the frame area 5.2 such that the connection between the frame element 5 and the catalyst layer 3 is fluid-tight. A common contact surface of the catalyst layer 3 and the frame element 5 completely surrounds the cutout surface 5.1.

[0017] The adhesive 6 is selected depending on the requirements for mechanical and chemical resistance as well as depending on the bonding method used, wherein the adhesive 6 is so-called hot-melt adhesive, UV adhesive, two-component adhesive or another adhesive.

[0018] The membrane arrangement 1 additionally comprises a first gas diffusion layer 7 and a second gas diffusion layer 8, wherein the first gas diffusion layer 7 is guided from the lower catalyst layer 3 through the cutout area 5.1 of the frame element 5 to a first bipolar plate 9. The second gas diffusion layer 8 is arranged above the upper catalyst layer 8 and leads to a second bipolar plate 10.

[0019] To seal the membrane arrangement 1 to the bipolar plates 9, 10 and port areas not shown in detail, the membrane arrangement 1 further has seals 11 to 14, which are each arranged on one side of the frame element 5 and are directed towards the respective associated bipolar plate 9, 10.

[0020] In further embodiments not shown in detail, one or more frame elements 5 may be provided which are coupled to the membrane 2 or at least one of the catalyst layers 3, 4. Furthermore, the seals 11 to 14 may be present only on one side and in a different number.

[0021] In the Fig. 2A to 2C are different steps S1 to S3 of a first embodiment of a method according to the invention for producing the membrane arrangement 1 according to Fig. 1 shown.

[0022] In this process, the membrane 2 and the catalyst layers 3, 4 are first applied to the frame element 5 in a manner not shown, whereby the catalyst layer 3 is bonded to the frame element 5.

[0023] In a first step S1, the frame element 5 with the applied membrane 2 and the catalyst layers 3, 4 is placed into a lower injection mold 15. A cover element 16 is placed on the top of the frame element 5.

[0024] The lower injection mold 15 has two mold elements 15.1, 15.2 for receiving sealing material. The mold elements 15.1, 15.2 are connected to each other or formed separately. A injection distributor 15.3 is provided for feeding the sealing material into the mold elements 15.1, 15.2. To produce the seals 11 and 14, the sealing material is injection-molded onto the underside of the frame element 5, with the seals 11 and 14 receiving their shape by means of the mold elements 15.1, 15.2. The sealing material is in particular an elastomer, preferably silicone and / or ethylene propylene diene monomer rubber (EPDM).

[0025] Prior to production, an adhesion promoter, a primer, an adhesion improver and / or other adhesion enhancers can be applied to the frame element 5 in a manner not shown in detail, so that the adhesion of the sealing material is improved.

[0026] In a second step S2, the cover element 16 is replaced by an upper injection mold 17 with two mold elements 17.1, 17.2, whereby the sealing material is injected onto the top of the frame element 5 by means of a runner 17.3 to produce the seals 12 and 13. The runner 15.3 and the runner 17.3 can be the same tool.

[0027] The injection distributors 15.3, 17.3 and the respective associated mold elements 15.1, 15.2, 17.1, 17.2 can also form a common unit.

[0028] In one embodiment of the process, the seals 11 to 14 are applied to the frame element 5 in reverse order or simultaneously.

[0029] In a third step S3, the form elements 15.1, 15.2, 17.1, 17.2 are detached from the frame element 5. This preferably only occurs when the seals 11 to 14 have reached a predetermined strength at which plastic deformation is avoided.

[0030] In exemplary embodiments not shown in detail, the membrane 2 and / or the catalyst layers 3, 4 are directly connected to the seals 11 to 14.

[0031] The Fig. Figures 3A to 3C show various steps S1 to S3 of a second embodiment of a method according to the invention for producing the membrane arrangement 1. Fig. 1.

[0032] As already described, the seals 11 to 14 are applied to the frame element 5 by injection molding. In contrast to the one described in the Fig. In the first embodiment shown in 2A to 2C, however, the membrane 2 and the catalyst layers 3, 4 are only applied to the frame element 5 in the third step S3 after the production of the seals 11 to 14, whereby the catalyst layer 3 is bonded to the frame element 5.

[0033] In the Fig. 4A to 4C are different steps S1 to Sn of a third embodiment of a method according to the invention for producing the membrane arrangement 1 according to Fig. 1 shown.

[0034] In the first step S1, five initial layers 18, 19 are applied to the top surface of the frame element. These layers 18, 19 are sealants, adhesion promoters, primers, adhesion improvers, or layers 18, 19 that perform several of these functions.

[0035] Subsequently, in a second step, S2 seals 12, 13 are applied to layers 18, 19 using a printing process, spraying process, casting process, injection molding process or other method. The application is carried out in discrete steps and / or continuously in any combination.

[0036] After the production of layers 18, 19 and seals 12, 13, further layers 20, 21 and the additional seals 11, 14 are produced in further steps S3 to Sn-1 (not shown). This is done in accordance with the production of layers 18, 19 and seals 12, 13.

[0037] In a final step, the membrane 2 and the catalyst layers 3, 4 are applied to the frame element 5 after the seals 11 to 14 and layers 18 to 21 have been produced, with the catalyst layer 3 being bonded to the frame element 5. In exemplary embodiments not shown in detail, this application can also take place before the seals 11 to 14 and layers 18 to 21 have been produced.

[0038] It is still possible to produce identical or different seals 11 to 14 and / or layers 18 to 21.

[0039] The Fig. Figures 5A to 5D show various steps S1 to Sn of a fourth embodiment of a method according to the invention for producing the membrane arrangement 1. Fig. 1. The production of the seals 11 to 14 and the layers 18 to 21 is carried out according to the [document / section] in Fig. The third embodiment described in 4A to 4C.

[0040] In addition, after the application of the seals 11 to 14, the seals 11 to 14 are shaped, the shaping being carried out by means of shaping elements 22, 23.

[0041] Alternatively or additionally, the forming is carried out after the application of the seals 11 to 14 or simultaneously in a manner not shown in detail, using forming elements 15.1, 15.2, 17.1, 17.2 according to the Fig. 2A to 2C, dies, stamps, embossing tools and other tools. The forming process also takes place in discrete steps and / or continuously in any combination.

[0042] Forming can involve pure shaping, rolling, embossing, compacting, and / or pressing. The forming process can be the same for different areas and / or completely or partially different. The forming steps can be performed simultaneously and / or sequentially.

[0043] In Fig. 6 are different steps S1 to Sn of a fifth embodiment of a method according to the invention for producing the membrane arrangement 1 according to Fig. 1 shown.

[0044] To produce the seals 11 to 14, in the first step S1, layers 18 and 19 are applied to the frame element 5 using a first rotary tool 24. Layers 18 and 19 consist of sealing material or are an adhesion promoter, primer, and / or adhesion improver. The frame element 5 is supplied as a roll of material, allowing for the continuous application of layers 18 to 21 and the seals 11 to 14.

[0045] In the second step S2, the sealing material is then applied to layers 18 and 19 using a second rotary tool 25, thus creating the seals 12 and 13. It is possible to apply one or more seals, which can be identical or different in design.

[0046] After the seals 12, 13 have been applied, they are formed in the third step S3 using a third rotary tool 26.

[0047] Forming can involve pure shaping, rolling, embossing, compacting, and / or pressing. The forming process can be the same for different areas and / or completely or partially different. The forming steps can be performed simultaneously and / or sequentially.

[0048] After the production of layers 18, 19 and seals 12, 13, further layers 20, 21 and the additional seals 11, 14 are produced in further steps S4 to Sn-1 (not shown). This is done according to the production process for layers 18, 19 and seals 12, 13.

[0049] In a final step, the membrane 2 and the catalyst layers 3, 4 are applied to the frame element 5 after the seals 11 to 14 and layers 18 to 21 have been produced, with the catalyst layer 3 being bonded to the frame element 5. In exemplary embodiments not shown in detail, this application can also take place before the seals 11 to 14 and layers 18 to 21 have been produced.

[0050] In summary, for all described embodiments, the components of the membrane assembly 1 shown, i.e., the membrane 2, the catalyst layers 3, 4, the frame element 5, the adhesive 6, the seals 11 to 14, and the layers 18 to 21, as well as the bipolar plates 9, 10, can be combined with one another in any way. This includes combining different numbers of components and bipolar plates 9, 10, as well as different arrangements. The components, in particular the frame element 5, are processed as individual parts and / or as rolled material.

[0051] Furthermore, for all embodiments, the application methods shown can be carried out discretely and / or continuously and / or in any combination, and the sequence of application and fixing of the components is arbitrary.

[0052] Furthermore, different adhesive materials, sealing materials, and layer materials can be used for the adhesive 6, the seals 11 to 14, and the layers 18 to 21. For example, different adhesive materials, sealing materials, and layer materials are used for the cathode side, the anode side, the membrane 2, the gas diffusion layers 7 and 8, the frame 5, and the other components.

[0053] These materials are preferably specially adapted to their use and exhibit the same and / or different properties and resistances.

[0054] The adhesive materials, sealing materials, and coating materials can be applied in any desired form and can be applied to the components in solid, liquid, paste, and / or melt form using one or more application methods. These application methods include, among others, spraying, doctor blade application, screen printing, roller engraving, pad printing, and / or methods using nozzles and / or die nozzles.

[0055] The drying and / or curing of the adhesive materials, sealing materials, and coating materials is achieved using heat, cold, pressure, vacuum, ultraviolet radiation, infrared radiation, and / or over a specific period of time. For cooling, preferably individual cooling zones or several cooling zones in combination are provided.

[0056] Furthermore, the adhesive materials, sealing materials, and coating materials, as well as the components of the membrane assembly 1 and the bipolar plates 9, 10, can be pretreated, fixed, activated, pre-dried, and / or fully dried. Additionally, one or more components of the adhesive materials, sealing materials, and coating materials are applied, and / or reactions occur on the components and / or within the assembled components. These reactions include, for example, hardening and / or polymerization.

Claims

[1] Method for manufacturing a membrane arrangement (1) for a fuel cell, wherein the membrane arrangement (1) is formed from at least a frame element (5), a membrane (2) surrounding the edge of the frame element (5) and a seal (11 to 14), wherein the seal (11 to 14) is applied to the frame element (5), characterized by , that one or more further layers (18 to 21) are arranged between the frame element (5) and the seal (11 to 14). [2] Method according to claim 1, wherein to produce the seal (11 to 14) the frame element (5) is placed in an injection mold (15, 17) and a sealing material is injected onto the frame element (5). [3] Method according to claim 1 or 2, wherein to produce the seal (11 to 14) a sealing material is applied to the frame element (5) and then shaped. [4] Method according to one of the preceding claims, wherein to produce the seal (11 to 14) a sealing material is applied to the frame element (5) by means of a rotary tool (25) and is subsequently shaped by means of a further rotary tool (26). [5] Method according to one of the preceding claims, wherein the membrane (2) and / or at least a catalyst layer (3, 4) arranged on the membrane (2) are attached to the frame element (5). [6] Method according to one of the preceding claims, wherein first the seal (11 to 14) is applied to the frame element (5) and then the membrane (2) and / or the at least one catalyst layer (3, 4) is attached to the frame element (5). [7] Method according to any one of claims 1 to 5, wherein first the membrane (2) and / or the at least one catalyst layer (3, 4) is attached to the frame element (5) and then the seal (11 to 14) is applied to the frame element (5).

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