Fluid transport component and method for producing the fluid transport component

Abstract

The invention relates to a fluid transport component (1) for an electrolyser, having a gas diffusion layer (2) which comprises a metal and is porous, and having a porous transport layer (3) which comprises a carbon paper and / or a carbon nonwoven, characterised in that the gas diffusion layer (2) is integrally bonded and electrically conductively connected to the porous transport layer (3). The invention additionally relates to a method for producing a fluid transport component (1) for an electrolyser, having the following steps: a) providing a gas diffusion layer (2) which comprises a metal and is porous; b) providing a porous transport layer (3) which comprises a carbon paper and / or a carbon nonwoven; and c) integrally bonding and electrically conductively connecting the gas diffusion layer (2) to the porous transport layer (3).

Description

[0001] 2024PF00249

[0002] 1

[0003] Description

[0004] Fluid transport component and method for manufacturing the fluid transport component

[0005] The invention relates to a fluid transport component for an electrolyzer and a method for manufacturing the fluid transport component. Furthermore, the invention relates to the electrolyzer and a method for manufacturing the electrolyzer.

[0006] A conventional electrolyzer for splitting water into hydrogen and oxygen comprises numerous components that must be assembled. For example, the electrolyzer may include a proton exchange membrane with an anode and a cathode applied as catalytic layers. It may also include a bipolar plate and gas diffusion layers through which the water, hydrogen, and oxygen can be transported. Additionally, a porous transport layer may be present. Conventionally, the electrolyzer consists of a cell stack containing a large number of electrochemical cells, thus multiplying the number of components to be assembled. This makes the manufacturing process complex and prone to errors.

[0007] The object of the invention is therefore to create a component for an electrolyzer and a method for manufacturing the component, wherein the electrolyzer can be manufactured with little effort and little susceptibility to errors.

[0008] The fluid transport component according to the invention for an electrolyzer has a gas diffusion layer which comprises a metal and is porous, and a porous transport layer which comprises carbon paper and / or a carbon fleece, wherein the gas diffusion layer is materially bonded and 2024PF00249

[0009] 2 is electrically conductive and connected to the porous transport layer.

[0010] This means that instead of two separate components – the gas diffusion layer and the porous transport layer – the electrolyzer requires only a single component, the fluid transport component according to the invention, for both the gas diffusion layer and the porous transport layer. This makes the electrolyzer advantageously simpler and less prone to defects to manufacture. Furthermore, by connecting the gas diffusion layer and the porous transport layer in a materially coherent and electrically conductive manner, the contact resistance between the gas diffusion layer and the porous transport layer can be reduced, resulting in a higher efficiency for the electrolyzer.

[0011] The gas diffusion layer and the porous transport layer are preferably bonded together by means of an electrically conductive adhesive. The electrically conductive adhesive can, for example, comprise electrically conductive fibers and / or electrically conductive particles to make the adhesive electrically conductive. The electrically conductive fibers can, for example, be carbon fibers. The electrically conductive particles can, for example, comprise carbon, in particular graphite and / or carbon black. Electrically conductive adhesives are commercially available, for example, under the brand name Loctite.

[0012] It is preferred that the gas diffusion layer and the porous transport layer are bonded together in a coherent and electrically conductive manner by means of a sacrificed adhesive. The adhesive can, for example, be sacrificed and / or burned out by the application of heat.

[0013] It is preferred that the porous transport layer has a layer of a carbon fleece prestructure. The 2024PF00249

[0014] The prestructure can, for example, comprise oxidized polyacrylonitrile fibers (commercially available under the brand name Panox, for instance) and / or viscose fibers (also known as rayon fibers), or consist entirely of oxidized polyacrylonitrile fibers and / or viscose fibers. It is preferred that the gas diffusion layer has a woven area in which the prestructure is interwoven with the gas diffusion layer, wherein a continuous coating, which is electrically conductive and contains carbon, is applied to both the gas diffusion layer and the prestructure, thereby forming the carbon fleece.Additionally or alternatively, the fluid transport component can have an additional layer with the prestructure of the carbon fleece, wherein the additional layer is welded and / or sintered to the gas diffusion layer and contacts the layer of the prestructure, wherein a continuous coating is applied to the gas diffusion layer, to the prestructure which is arranged in the layer of the prestructure and to the prestructure which is arranged in the additional layer of the prestructure, which is electrically conductive and contains carbon.

[0015] The fluid transport component preferably comprises a wire that is inserted into the porous transport layer, has a metal content, is electrically conductive and is welded and / or sintered to the gas diffusion layer, and / or fibers that are inserted into the porous transport layer, have a metal content, are electrically conductive and are welded and / or sintered to the gas diffusion layer.

[0016] It is preferred that the gas diffusion layer has a coating containing carbon, wherein the coating and the porous transport layer are sintered together.

[0017] The electrolyzer according to the invention comprises a fluid transport component according to the invention or preferably a 2024PF00249

[0018] The implementation form of this is derived from the porous transport layer. Preferably, the porous transport layer contacts a cathode of the electrolyzer. The electrolyzer can, for example, be configured to split water into hydrogen and oxygen. The electrolyzer can have several electrochemical cells connected in series, each electrochemical cell having one of the fluid transport components.

[0019] The inventive method for manufacturing a fluid transport component for an electrolyzer comprises the steps of: a) providing a gas diffusion layer comprising a metal and being porous; b) providing a porous transport layer comprising carbon paper and / or a carbon fleece; and c) materially bonding and electrically conductively connecting the gas diffusion layer to the porous transport layer.

[0020] It is preferred that in step c) the gas diffusion layer and the porous transport layer are bonded together using an electrically conductive adhesive.

[0021] Alternatively, it is preferred that in step c) the gas diffusion layer and the porous transport layer are bonded together using an adhesive and then the adhesive is heated until it decomposes, in particular until it burns.

[0022] The porous transport layer preferably comprises a layer of a carbon fleece prestructure. It is preferred that in step c) the prestructure of the prestructure layer is interwoven with a woven area of ​​the gas diffusion layer, and subsequently a continuous coating, which is electrically conductive and contains carbon, is applied to the gas diffusion layer and the prestructure, thereby forming the carbon fleece. Alternatively or additionally, it is preferred that in step c) an additional layer of the fluid transport component, which comprises the carbon fleece prestructure, is interwoven with the 2024PF00249

[0023] 5

[0024] The gas diffusion layer is welded and / or sintered, is contacted with the layer of the prestructure, and then a continuous coating is applied to the gas diffusion layer, to the prestructure located in the layer of the prestructure, and to the prestructure located in the additional layer. This coating is electrically conductive and contains carbon.

[0025] It is preferred that in step c) a wire comprising a metal and being electrically conductive is introduced into the porous transport layer and subsequently welded and / or sintered to the gas diffusion layer and / or fibers comprising a metal and being electrically conductive are introduced into the porous transport layer and subsequently welded and / or sintered to the gas diffusion layer.

[0026] In step c), a coating containing carbon is preferably applied to the metal, and then the coating and the porous transport layer are sintered together.

[0027] The term "coating" refers both to the coating applied to the gas diffusion layer and to the contiguous coating applied to the gas diffusion layer and the prestructure. The coating can be hydrogen-free, resulting in particularly strong adhesion. Alternatively, the coating can contain hydrogen, which can provide exceptional stability and very low electrical resistance.

[0028] The coating preferably comprises carbon with a proportion of at least 90 wt%, in particular at least 95 wt% or at least 99 wt%. It is preferred that the coating consists, apart from unavoidable impurities, of carbon and optionally hydrogen. 2024PF00249

[0029] 6

[0030] Alternatively, it is preferred that the coating be doped with chromium, chromium carbide, silicon, tungsten, nitrogen, fluorine, hydrogen, and / or silicon carbide. Doping increases the hardness and durability of the coating. The doping can be produced, for example, by evaporating a first source containing carbon and a second source, separate from the first and containing the dopant, in a coating process. The coating can consist, with the exception of unavoidable impurities, of carbon, chromium, chromium carbide, silicon, tungsten, nitrogen, fluorine, hydrogen, and / or silicon carbide, and optionally hydrogen.

[0031] It is conceivable that the coating is applied using a spraying process, a coating process, a dipping process, a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process and / or a conversion process.

[0032] In the spraying, application, and immersion processes, a suspension containing carbon and a liquid can be used. The solvent is then removed, for example, by applying heat.

[0033] The conversion process can, for example, involve plasma carburizing or plasma nitrocarburizing. These processes have the advantage of preventing surface oxidation, which would otherwise lead to an increase in contact resistance. Furthermore, these processes have the advantage of increasing the hardness of the gas diffusion layer through the introduction of carbon.

[0034] The physical vapor deposition process can involve cathode sputtering (magnetron sputtering), in particular 2024PF00249

[0035] 7. Reactive cathode sputtering, or arc evaporation, in particular reactive arc evaporation, can be used. Targets can include, for example, chromium, a chromium-containing alloy, iron, an iron-containing alloy, carbon, silicon, a silicon-containing alloy, wolfram, and / or a wolfram-containing alloy. Reactive gases can include, for example, ethyne, hexamethyldisiloxane (HDMSO), tetramethylsilane (TMS), and / or nitrogen.

[0036] The chemical vapor deposition process can, for example, be a plasma-assisted vapor deposition (PACVD) process. Targets such as chromium, iron, carbon, silicon, and / or wolfram can be used. Reactive gases such as ethyne, hexamethyldisiloxane (HDMSO), tetramethylsilane (TMS), and / or nitrogen can be used.

[0037] The coating can be applied directly to the metal, especially if the coating is applied using the conversion process.

[0038] Alternatively, the gas diffusion layer could have an adhesion promoter layer applied directly to the metal, particularly if the coating is applied using a process different from the conversion process. The adhesion promoter layer can contain chromium and / or iron at a concentration of at least 90 wt%, in particular at least 95 wt% or at least 99 wt%. Furthermore, the adhesion promoter layer can have a thickness in the range of 0.01 pm to 0.5 pm, in particular 50 nm to 200 nm. It is conceivable to apply the adhesion promoter layer using a PVD process or a CVD process. The coating can be applied directly to the adhesion promoter layer. 2024PF00249

[0039] Alternatively, instead of applying the coating directly to the adhesion promoter layer, the gas diffusion layer can have an intermediate layer applied directly to the adhesion promoter layer. This intermediate layer comprises a metal nitride, a metal carbide, a metal carbonitride, a semimetal carbide, a semimetal carbonitride, and / or a semimetal nitride with a proportion of at least 90% by mass, in particular at least 95% by mass or at least 99% by mass, with the coating being applied directly to the intermediate layer. Providing the intermediate layer reduces the likelihood of coating delamination and also prevents hydrogen from entering the adhesion promoter layer during electrolyzer operation.The intermediate layer can, for example, consist of chromium nitride, CrC, CrCN, FeC, FeN, Fe-doped CN, and / or Fe-Cr-N, or consist entirely of chromium nitride, CrC, CrCN, FeC, FeN, Fe-doped CN, and / or Fe-Cr-N, except for unavoidable impurities. The intermediate layer can have a thickness ranging from 0.01 pm to 1 pm or from 0.01 pm to 0.5 pm. It is conceivable to apply the intermediate layer using a PVD or CVD process. The adhesion promoter layer electrically connects the metal to the coating. If the intermediate layer is not used, the adhesion promoter layer directly connects the metal to the coating electrically. In the case where the intermediate layer is provided, the adhesion promoter layer indirectly connects the metal to the coating via the intermediate layer in an electrically conductive manner.

[0040] It is conceivable that the bonding agent layer and, optionally, the intermediate layer are also applied to the pre-structure. 2024PF00249

[0041] The metal can be, for example, a stainless steel, in particular with material no. 1.4404.

[0042] The inventive method for manufacturing an electrolyzer comprises the steps of: - manufacturing a fluid transport component according to the inventive method or a preferred embodiment thereof; - contacting the porous transport layer with a cathode of the electrolyzer.

[0043] The invention will be explained in more detail below with reference to the attached schematic drawings. These show

[0044] Figure 1 shows a section through a first embodiment of the inventive fluid transport component.

[0045] Figure 2 shows a section through a second embodiment of the inventive fluid transport component.

[0046] Figure 3 shows a section through a third embodiment of the inventive fluid transport component.

[0047] Figure 4 shows a section through a fourth embodiment of the inventive fluid transport component.

[0048] Figure 5 shows a section through a fifth embodiment of the fluid transport component according to the invention and

[0049] Figure 6 shows a section through a sixth embodiment of the fluid transport component according to the invention.

[0050] As can be seen from Figures 1 to 6, a fluid transport component 1 for an electrolyzer has a gas diffusion layer 2, which comprises a metal and is porous, and a porous transport layer 3, which comprises carbon paper and / or a carbon fleece, wherein the gas diffusion layer 2 is materially and electrically conductively connected to the porous transport layer 3. 2024PF00249

[0051] 10

[0052] In particular, the gas diffusion layer 2 can consist of the porous metal. The metal can be stainless steel, in particular with material number 1.4404. In particular, the porous transport layer 3 can consist of carbon paper and / or carbon fleece. The porous transport layer 3 can be electrically conductive.

[0053] The gas diffusion layer 2 can have a first gas diffusion layer surface 12, and the porous transport layer 3 can have a first transport layer surface 13, which is arranged facing the gas diffusion layer surface 12. In particular, the gas diffusion layer surface 12 and the first transport layer surface 13 can be arranged parallel to each other. The porous transport layer 3 can also have a second transport layer surface 14, which is arranged away from the first transport layer surface 13. The first transport layer surface 13 and the second transport layer surface 14 can, for example, be arranged parallel to each other.

[0054] An electrolyzer can include the fluid transport component 1, wherein the porous transport layer 3 may contact a cathode of the electrolyzer. In particular, the second transport layer surface 14 contacts the cathode. The electrolyzer can be configured to decompose water into hydrogen and oxygen. The electrolyzer can include several electrochemical cells connected in series, each of the electrochemical cells having one of the fluid transport components 1.

[0055] In the first embodiment of the fluid transport component shown in Figure 1, the gas diffusion layer 2 and the porous transport layer 3 are bonded together by means of an electrically conductive adhesive 4. 2024PF00249

[0056] 11

[0057] In the second embodiment shown in Figure 2, the fluid transport component 1 has a sacrificial layer 5 containing an adhesive that bonds the gas diffusion layer 2 and the porous transport layer 3 together. The adhesive can be electrically conductive or non-conductive. By sacrificing the sacrificial layer 5, for example by applying heat, the gas diffusion layer and the porous transport layer 3 can be bonded together in a materially coherent and electrically conductive manner.

[0058] In the third embodiment shown in Figure 3 and the fourth embodiment shown in Figure 4, the porous transport layer 3 has a layer 8 of a carbon fleece prestructure. In the third embodiment, the gas diffusion layer 2 has a woven area 6 in which the prestructure is interwoven with the gas diffusion layer 2. A portion of the prestructure may protrude from the gas diffusion layer 2. A continuous, electrically conductive, carbon-containing coating is applied to the gas diffusion layer 2 and to the prestructure, thereby forming the carbon fleece.In the fourth embodiment, the fluid transport component 1 has an additional layer 9 with the carbon fleece prestructure, wherein the additional layer 8 is welded and / or sintered to the gas diffusion layer 2 and contacts layer 8 of the prestructure. A continuous coating 10, which is electrically conductive and contains carbon, is applied to the gas diffusion layer 2, to the prestructure located in layer 8 of the prestructure, and to the prestructure located in additional layer 9 of the prestructure. Layer 8 of the prestructure and additional layer 9 of the prestructure can be separate components that are only brought together to manufacture the fluid transport component 1. 2024PF00249.

[0059] 12

[0060] In the fifth embodiment shown in Figure 5, the fluid transport component 1 has a wire 7 which is inserted into the porous transport layer 3, has a metal, is electrically conductive and is welded and / or sintered to the gas diffusion layer 2, and / or has fibers which are inserted into the porous transport layer 3, have a metal, are electrically conductive and are welded and / or sintered to the gas diffusion layer 2.

[0061] Figure 6 shows a sixth embodiment in which the gas diffusion layer 2 has a coating 10 which contains carbon, wherein the coating 10 and the porous transport layer 3 are sintered together.

Claims

2024PF00249 13 Patent claims 1. Fluid transport component for an electrolyzer, comprising a gas diffusion layer (2) which has a metal and is porous, and a porous transport layer (3) which has a carbon paper and / or a carbon fleece, characterized in that the gas diffusion layer (2) is materially and electrically connected to the porous transport layer (3).

2. Fluid transport component according to claim 1, wherein the gas diffusion layer (2) and the porous transport layer (3) are connected to each other in a coherent and electrically conductive manner by means of an electrically conductive adhesive (4).

3. Fluid transport component according to claim 1, wherein the gas diffusion layer (2) and the porous transport layer (3) are connected to each other in a coherent and electrically conductive manner by means of a sacrificed adhesive material.

4. Fluid transport component according to one of claims 1 to 3, wherein the porous transport layer (3) comprises a layer (8) of a carbon fleece prestructure.

5. Fluid transport component according to claim 4, wherein the gas diffusion layer (2) has a weaving area (6) in which the prestructure is interwoven with the gas diffusion layer (2), wherein a continuous coating (10) is applied to the gas diffusion layer (2) and to the prestructure, which is electrically conductive and contains carbon, thereby forming the carbon fleece.

6. Fluid transport component according to claim 4 or 5, wherein the fluid transport component (1) has an additional layer (9) with the prestructure of the carbon fleece, wherein the additional layer (8) is welded and / or sintered to the gas diffusion layer (2) and the layer (8) of the prestructure 2024PF00249 14 contacted, wherein a continuous coating (10) which is electrically conductive and contains carbon is applied to the gas diffusion layer (2), to the prestructure which is arranged in layer (8) of the prestructure and to the prestructure which is arranged in the additional layer (9) of the prestructure.

7. Fluid transport component according to one of claims 1 to 6, wherein the fluid transport component (1) comprises a wire (7) which is inserted into the porous transport layer (3), has a metal, is electrically conductive and is welded and / or sintered to the gas diffusion layer (2), and / or has fibers which are inserted into the porous transport layer (3), have a metal, are electrically conductive and are welded and / or sintered to the gas diffusion layer (2).

8. Fluid transport component according to one of claims 1 to 7, wherein the gas diffusion layer (2) has a coating (10) comprising carbon, wherein the coating (10) and the porous transport layer (3) are sintered together.

9. Method for manufacturing a fluid transport component (1) for an electrolyzer, comprising the steps of: a) providing a gas diffusion layer (2) which has a metal and is porous; b) providing a porous transport layer (3) which has a carbon paper and / or a carbon fleece; and c) materially bonding and electrically conductively connecting the gas diffusion layer (2) to the porous transport layer (3).

10. Method according to claim 9, wherein in step c) the gas diffusion layer (2) and the porous transport layer (3) are bonded together by means of an electrically conductive adhesive (4). 2024PF00249 15 11. Method according to claim 9, wherein in step c) the gas diffusion layer (2) and the porous transport layer (3) are bonded together by means of an adhesive (4) and subsequently the adhesive (4) is heated until the adhesive (4) has decomposed, in particular has burned.

12. Method according to any one of claims 9 to 11, wherein the porous transport layer (3) comprises a layer (8) of a prestructure of the carbon fleece, wherein in step c) the prestructure of layer (8) of the prestructure is interwoven with a weaving area (6) of the gas diffusion layer (2) and subsequently a continuous coating (10) is applied to the gas diffusion layer (2) and to the prestructure, which is electrically conductive and contains carbon, thereby forming the carbon fleece.

13. Method according to any one of claims 9 to 12, wherein the porous transport layer (3) has a layer (8) of a prestructure of the carbon fleece, wherein in step c) an additional layer (9) of the fluid transport component (1) having the prestructure of the carbon fleece is welded and / or sintered to the gas diffusion layer (2), is contacted with the layer (8) of the prestructure and subsequently a continuous coating (10) having electrical conductivity and having carbon is applied to the gas diffusion layer (2), to the prestructure which is arranged in the layer (8) of the prestructure and to the prestructure which is arranged in the additional layer (9).

14. Method according to any one of claims 9 to 13, wherein in step c) a wire (7) comprising a metal and being electrically conductive is introduced into the porous transport layer (3) and is subsequently welded and / or sintered to the gas diffusion layer (2) and / or fibers comprising a metal and being electrically conductive are introduced into the porous transport layer (3) and 2024PF00249 16 subsequently welded and / or sintered with the gas diffusion layer (2).

15. Method according to any one of claims 9 to 14, wherein in step c) a coating (10) comprising carbon is applied to the metal, and subsequently the coating (10) and the porous transport layer (3) are sintered together.

Images