Electrolytic cell having optimised contacting of a catalyst layer

Abstract

The invention relates to an electrolytic cell (01) for the electrolysis of CO2. The electrolytic cell (01) comprises, in direct or indirect sequence, a cathode plate (04), a gas chamber (06), a gas-diffusion layer (08), a catalyst layer (09), a water chamber (07) and an anode plate (05). According to the invention, the gas diffusion layer (08) comprises an electrically non-conductive main body (12) and an electrically conductive grid (13), wherein at least the majority of the grid (13) is arranged within the main body (12). The catalyst layer (09) is contacted via a plurality of grid contact points (14).

Description

Description TITLE Electrolysis cell with optimized contacting of a catalyst layer TECHNICAL FIELD

[0001] The invention relates to an electrolysis cell for the electrolysis of CO2. This cell comprises a gas chamber containing CO2 and a water chamber containing an electrolyte, which are separated from each other by a gas diffusion layer and a catalyst layer. Contacting of the catalyst layer is required. BACKGROUND D

[0002] Renewable electricity, such as solar and wind power, can be provided in some locations in quantities that exceed local demand. The effective use of available electricity is problematic in this case. One possibility is the electrolysis of water to produce hydrogen and oxygen. However, the storage and transport of hydrogen are problematic. Furthermore, it is known that available renewable electricity can be utilized through the electrochemical conversion of CO2, capturing the greenhouse gas CO2 as a product. The electrochemical reduction reaction of carbon dioxide (CO2) to hydrocarbons through CO2 electrolysis represents a promising alternative to other energy storage strategies.

[0003] Electrolysis cells are used to reduce CO2. On one side, there is an anode, which is separated from a liquid electrolyte by a membrane. Inside the electrolysis cell is the cathode, which is in contact with the CO2 to be reduced. When the appropriate voltage is applied between the anode and the cathode, electrolysis of the CO2 takes place. For this purpose, the electrolysis cell used in regular applications has a cavity adjacent to the cathode on the side facing the anode to accommodate the electrolyte. Opposite is a cavity for holding the CO2, separated by a gas diffusion electrode.

[0004] The general functioning of an electrolysis cell for the electrolysis of CO2 is well known to those skilled in the art. It is described, for example, in WO2023 / 217624A1 or WO2019 / 096985A1. It has proven advantageous if the gas diffusion electrode is formed by a non-conductive gas diffusion layer and a conductive catalyst layer. This requires contact between the catalyst layer. [00C6] The catalyst layer is usually contacted along its peripheral edge, for example, by applying copper strips. Provided the electrolysis cell is small, a sufficiently uniform voltage distribution across the surface of the catalyst layer can be achieved.

[0007] The problem is the limited conductivity of the catalyst layer and the thin layer thicknesses typically used for the catalyst layer. Combined with the need to provide a sufficient surface area for practical application, a sufficient and, in particular, uniform voltage between the catalyst layer and the anode cannot be easily guaranteed.

[0008] To solve the problem, known designs propose arranging a conductive grid, for example made of copper, on the catalyst layer opposite the gas diffusion layer, ie on the anode side in the electrolyte. However, this arrangement has several disadvantages. On the one hand, the arrangement of the conductive grid in the electrolyte can have a detrimental effect on the electrochemical process. Another disadvantage is the smaller distance between the anode and the conductive grid compared to the distance between the anode and the Catalyst layer. Furthermore, the effective area of ​​the catalyst layer is reduced by the grid. SUMMARY OF THE INVENTION

[0010] The object of the present invention is to provide the most uniform voltage possible across the surface of the catalyst layer. The effective available area of ​​the catalyst layer should be as large as possible.

[0011] The object is achieved by an embodiment of the invention according to the teaching of claim 1. Advantageous embodiments are the subject of the dependent claims. [0G12 An electrolysis cell for the electrolysis of CO2 comprises, in direct or indirect sequence, a cathode end plate, a gas chamber, a gas diffusion layer, a catalyst layer, a water chamber and an anode end plate.

[0013] According to the invention, the gas diffusion layer comprises an electrically non-conductive base body and an electrically conductive grid, with the grid being arranged at least predominantly within the base body. Contact with the catalyst layer is achieved via a plurality of grid contact points. DESCRIPTION OF THE INVENTION

[0014] The generic electrolysis cell is intended for the electrolysis of CO2 and includes, as a direct or indirect consequence, - a cathode end plate, - a gas chamber, - a gas diffusion layer, - a catalyst layer, - a water chamber, and - an anode end plate. For the remainder of the description, reference is made to a left side, where the anode end plate is located, and an opposite right side. The terms "left side" and "right side" are chosen arbitrarily in this regard; however, in the following, they should always be understood that the left side refers to the side where the anode end plate is located, with the right side correspondingly being the opposite side of the electrolysis cell.

[0016] The cathode end plate and the anode end plate are the geometric ends of the respective electrolysis cell. In an arrangement of multiple electrolysis cells, a cathode end plate of one electrolysis cell can also form the anode end plate of the following electrolysis cell. The gas chamber is a cavity within the electrolysis cell to which CO2 is normally supplied during operation. The water chamber is another cavity that normally contains an electrolyte during operation.

[0018] The gas diffusion layer, together with the catalyst layer, forms a gas diffusion electrode. This separates the gas chamber from the water chamber. For functional reasons, it is necessary that the gas diffusion layer is permeable to CO2, but that the passage of liquid through the gas diffusion electrode is prevented.

[0019] First, the invention is based on the assumption that the gas diffusion layer is an electrically non-conductive layer. For this purpose, it has a base body made of an electrically non-conductive material as its essential element.

[0020] In contrast, the catalyst layer is particularly advantageously electrically conductive. To this end, it consists of an electrically conductive material or at least has an electrically conductive coating.

[0021] The catalyst layer forms the cathode of the electrolysis cell.

[0022] Furthermore, it is possible to construct the catalyst layer or the gas diffusion layer in multiple layers. For possible and advantageous layer structures, reference is made to the known state of the art.

[0023] It is obvious that the gas chamber, the gas diffusion layer, the catalyst layer, and the water chamber must be sealed all the way around to enable the gas chamber and the water chamber to be realized as cavities. Furthermore, it is obvious that appropriate connections are required for the introduction and discharge of fluids into and from the gas chamber and water chamber, respectively.

[0024] In a simple and advantageous manner, the gas chamber is directly adjacent to the cathode end plate.

[0025] It is particularly advantageous if the gas diffusion layer is directly adjacent to the gas chamber. Effective CO2 electrolysis can be achieved if the catalyst layer is directly adjacent to the gas diffusion layer.

[0027] It is particularly advantageous if the water chamber is directly adjacent to the catalyst layer. In any case, an anode is required. In one embodiment, the anode end plate may also serve as the anode of the electrolysis cell. In an alternative embodiment, an anode is arranged indirectly or, preferably, directly adjacent to the anode end plate.

[0029] It is particularly advantageous if the water chamber is separated from the anode by an anode membrane and the anode membrane is therefore directly adjacent to the water chamber.

[0030] An anode chamber may be arranged between the anode membrane and the anode. However, direct contact of the anode membrane with the anode is preferred.

[0031] For functional reasons, it is necessary that a voltage can be applied to the electrolysis cell. It is particularly advantageous if the power connection to the electrolysis cell is made on the left side at the anode end plate and on the opposite right side at the cathode end plate.

[0032] Alternatively, it can also be provided that the anode and / or the catalyst layer as a cathode are contacted to the outside separately from the anode end plate or cathode end plate.

[0033] To achieve the most uniform voltage distribution possible across the catalyst layer, electrical contact is established at a number of locations. However, the conventional arrangement of an electrically conductive grid in the water chamber is omitted.

[0034] In contrast, it is intended that an electrically conductive grid be arranged within the gas diffusion layer. However, it must be taken into account that the gas diffusion layer must initially be electrically non-conductive. Thus, it is necessary to form the gas diffusion layer from an electrically non-conductive base body, with an electrically conductive grid arranged at least predominantly within the base body. [0C35] The thickness and distribution of the grid can be chosen differently. At a minimum, the grid should make up only a small portion of the volume of the gas diffusion layer compared to the base body. Thus, the diffusion of CO2 is not unnecessarily impeded. It is important to ensure that the grid has the necessary electrical conductivity.

[0036] Thus, the gas diffusion layer comprises an electrically non-conductive base body and an electrically conductive grid, wherein the volume of the grid is preferably a maximum of 0.25 times the volume of the base body. Particularly preferably, the volume of the grid is less than 0.15 times the volume of the base body.

[0037] Furthermore, according to the invention, the grid on the left side adjacent to the catalyst layer extends to the surface of the gas diffusion layer at a plurality of locations, allowing contact with the catalyst layer at a plurality of grid contact points. This means that an electrically conductive connection to the catalyst layer is established via the grid contact points. The shape of the lattice can be just as diverse. It is not necessary for the lattice to be completely contained within the base body. It is assumed that at least half of the lattice (or its volume) is contained within the base body.

[0039] However, it is advantageous if at least two-thirds of the grid's volume is arranged within the base body. It is particularly advantageous if the grid is arranged essentially entirely within the base body, whereby the grid must be exposed at the grid contact points and at other locations for indirect contact with a cathode terminal, i.e., not enclosed by the base body. This design distributes the current flow to the catalyst layer across multiple grid contact points, thus allowing the current supply to the surface of the catalyst layer to be more than just the connection at the outer edge. This allows for flexible dimensioning of the electrolysis cell and eliminates the limitation to small sizes.

[0041] By arranging the electrically conductive grid in the gas diffusion layer, there is no need to arrange a conductive grid in the water chamber and thus in the electrolyte.

[0042] It is further provided that the grid comprises a plurality of metal filaments, at least the majority of which are enclosed in the base body. Accordingly, it is provided that the grid is integrally embedded in the gas diffusion layer. This means that the grid is inseparably fixed in the base body of the gas diffusion layer.

[0043] A particularly advantageous bonding of the metal threads within the gas diffusion layer can be realized by two different solutions according to the invention, both solutions being based on the metal threads being incorporated into the base body.

[0044] In a first variant of the invention, it is assumed that the base body consists at least partially of a single-layer or multi-layer woven or braided net of non-conductive plastic threads. Here, the grid is also formed in the form of a net, ie the metal threads are also woven or braided into the grid.

[0045] When designed in a mesh-like manner, it is necessary to combine the metal threads of the mesh with the mesh of the base body to achieve the advantageous bonding in the gas diffusion layer, creating a more stable mesh with an integrated mesh. Therefore, the metal threads of the mesh must be woven or braided into the mesh of the base body. In principle, it is sufficient to guide a plurality of metal threads to form the lattice through a mesh of the base body in only one direction, essentially parallel to one another. In this context, "essentially" refers to the metal threads running through the base body in a common direction, essentially parallel to one another.

[0047] In addition, a further advantageous embodiment for forming the electrically conductive grid can be selected, in which a plurality of first metal threads are guided along a first direction in a network of the base body, with a plurality of second metal threads traversing another layer of a network of the base body along a second direction, for example, transverse to the first direction. In this case, it is not initially intended that the first metal threads and the second metal threads be interwoven, braided, or otherwise connected to one another—rather, the metal threads are woven or braided within the respective network of plastic threads. For production purposes, it can be provided that the mesh is first produced from non-conductive plastic threads and then the metal threads are braided or woven in. However, it is particularly advantageous if the metal threads are woven or braided into the mesh of non-conductive plastic threads directly during the production of at least one mesh of the base body. The plastic threads and the metal threads are arranged alternately in the mesh.

[0050] Furthermore, it can be provided that a net comprising the electrically conductive grid and non-conductive plastic threads is combined with another net consisting only of non-conductive plastic threads.

[0051] Alternatively, in a second variant according to the invention, it can be provided that the grid comprises a plurality of metal threads analogous to the previous variant, but these are sewn into the base body. In this case, the base body is first manufactured from a non-conductive material or at least one layer of the base body, and then the metal threads are sewn into the base body or the layer of the base body. In this case, the base body or the layer of the base body can also be constructed as a mesh of plastic threads, as in the previous version. However, it is also possible to design it as a foamed body, for example.

[0053] The density and distribution of the metal threads and the non-conductive plastic threads can be advantageously determined based on the required cross-sections and the selected manufacturing process. It is obvious and advantageous that the peripheral edge of the catalyst layer can be electrically contacted without any reduction, so that the edge region of the catalyst layer is supplied with voltage. (005S] The electrically conductive connection of the grid arranged within the gas diffusion electrode to a cathode terminal is preferably effected on the circumferential outer circumference of the gas diffusion electrode via a plurality of connection points, ie at respective individual free ends of the grid.

[0056] The connection points can be arranged outside the base body, distributed around the outer circumference. It can also be provided that the base body is removed in sections to expose the connection points.

[0057] In a second contacting variant, a plurality of edge contact points are used on the grid. The edge contact points are designed to coincide with the grid contact points, i.e., they are also arranged on the surface of the base body on the left side, facing the catalyst layer. For contacting, a conductive layer—for example, a copper strip—can be applied to the surrounding edge of the gas diffusion layer, enabling contact at the edge contact points. In a third contacting variant, the grid is provided with a number of connection points. These can be designed analogously to the grid contact points, but are located opposite each other on the side facing the gas chamber. Thus, contact can be made with the grid via the plurality of connection points, and the current can be transferred to the catalyst layer in a distributed manner across the plurality of grid contact points.

[0059] It is obviously possible to combine the three different types of contact. In any case, it is necessary for the lattice to extend to the surface on the left side in several places, thus creating the lattice contact points. This enables contacting of the catalyst layer at the lattice contact points.

[0061] If, due to the design and / or the manufacturing process, no grid contact points are directly present, it can advantageously be provided that the gas diffusion layer on the left side is machined, for example ground, so that contact at the grid contact points can be ensured. (0C621 To ensure long-term stability without impairing electrolysis, it may be advantageous to provide the grid with a non-conductive coating. It is obvious that the grid contact points and connection points for contacting must be exposed.

[0063] To prevent the adhesion of any substances or molecules in the gas diffusion layer, it is particularly advantageous if the electrically conductive grid is provided with a hydrophobic coating. This prevents particles from adhering to the inherently conductive grid, which usually has hydrophilic properties – regardless of whether they occur during production / assembly or during operation or downtime – and thus reducing the free passage of CO2.

[0064] The number of lattice contact points per surface of the catalyst layer can be chosen differently. The larger the number, the The voltage distribution across the surface of the catalyst layer will be more uniform. However, the problem to consider is that with an increasing number of grid contact points, the effort required to produce the gas diffusion layer with the electrically conductive grid increases. An advantage over state-of-the-art solutions is achieved by having at least one grid contact point per 500 mm2. However, to avoid unnecessarily restricting the effective area of ​​the catalyst layer, the density of grid contact points should not exceed one grid contact point per 1 mm2.

[0066] It has proven advantageous to provide at least one grid contact point per 100 mm² of the catalyst layer area. Particularly preferred is a maximum of one grid contact point per 50 mm² of the catalyst layer area. In contrast, the number of grid contact points should preferably not exceed one grid contact point per 2 mm2. It is considered particularly preferable to have a maximum of one grid contact point per 4 mm2. To ensure a defined distance between the cathode end plate and the gas diffusion layer, especially to secure the position of the gas diffusion layer and the width of the gas chamber, it is particularly advantageous to insert at least one cathode-side spacer on the right side of the gas diffusion layer. This requires a defined position of the cathode-side spacer between the cathode end plate and the gas diffusion layer. The cathode-side spacer is intended to be in contact with the cathode end plate and, opposite, with the gas diffusion layer. It is obvious that the cathode-side spacer is located in the gas chamber or penetrates it. The cathode-side spacer is intended to ensure that the distance between the cathode end plate and the Gas diffusion layer not changed due to deformations of the gas diffusion layer.

[0070] Furthermore, depending on the dimensions of the electrolysis cell and the stiffness of the gas diffusion layer and the catalyst layer, it may be advantageous to arrange at least one anode-side spacer in the water chamber. This requires a defined position of the anode-side spacer between the anode end plate and the catalyst layer.

[0071] The anode-side spacer is intended to ensure that the distance between the anode end plate and the catalyst layer does not change due to deformation of the catalyst layer.

[0072] In conjunction with the cathode-side spacer, the anode-side spacer can reliably determine the position of the catalyst layer and the gas diffusion layer. This ensures the flat adhesion of the catalyst layer to the gas diffusion layer.

[0073] In a first option, several cathode-side spacers can be arranged in the gas chamber, or several anode-side spacers in the water chamber. In this case, the cathode-side spacers are to be firmly connected to the cathode end plate, or the anode-side spacers are to be firmly connected to the anode end plate, so that their position is fixed.

[0074] In the case of anode-side spacers firmly connected to the anode end plate, the anode must be designed to surround the spacers. It can be provided that the anode membrane also surrounds the spacers. If the shape of the anode membrane allows it, the anode and the spacers are preferably covered by the anode membrane.

[0075] In a second option, it can be provided that a one-piece cathode-side spacer is inserted between the cathode end plate and the gas diffusion layer or a one-piece anode-side spacer is inserted between the anode end plate and the catalyst layer in the water chamber.

[0076] The preferred design utilizes integral cathode-side spacers attached to the cathode endplate and a one-piece, mounted anode-side spacer located within the water chamber. Thus, there are no restrictions or overhead on the design of the anode and anode membrane.

[0077] To ensure the most unobstructed flow in the gas chamber or water chamber, a one-piece mounted spacer must be designed in a grid-like manner. The covered area of ​​the gas diffusion layer or catalyst layer should be as small as possible, and the grid-like spacer should otherwise be spaced apart from the cathode end plate or anode end plate, and especially from the gas diffusion layer or catalyst layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] FIG 1 shows schematically in section a first embodiment of the structure of an electrolysis cell according to the invention with an electrically conductive grid arranged within the non-conductive gas diffusion layer.

[0079] FIG 2 shows a schematic section through a second embodiment of the structure of an electrolysis cell according to the invention analogous to the first embodiment, wherein the position of the gas diffusion electrode is fixed by spacers.

[0080] FIG 3 shows schematically the possible shape for a grid that can be embedded in the gas diffusion layer.

[0081] FIG 4 shows schematically a gas diffusion view with integrated conductive grid. DESCRIPTION OF THE EMBODIMENT

[0082] Figure 1 outlines a first embodiment of an electrolysis cell 01 according to the invention. This simplified sketch shows the structure of the electrolysis cell 01 in the sequence from the right side 02 to the left side 03.

[0083] On the right side 02 is the cathode end plate 04. The cathode-side power connection is usually made at the cathode end plate 04. Adjacent to the cathode end plate 04 is the gas chamber 06. During operation of the electrolysis cell 01, the carbon dioxide (CO2) to be converted is fed to the gas chamber.

[0084] The anode end plate 05 is located on the left side 03. The anode-side power connection is intended to be made on the left side, preferably at the anode end plate 05. In the figure, the water chamber 07 is sketched adjacent to the anode end plate 05. During implementation, it must be taken into account that the anode is located at, or forms, the anode end plate 05. To create the electrolysis cell, the anode must in turn be separated from the water chamber 07 by an anode membrane. During operation of the electrolysis cell 01, the electrolyte for enabling electrolysis is located in the water chamber 07.

[0085] The gas chamber 06 is separated from the water chamber 07 by a gas diffusion electrode. This consists of a gas diffusion layer 08 and a catalyst layer 09. The gas diffusion layer 08 is electrically non-conductive, while the catalyst layer 09 is electrically conductive.

[0086] To enable CO2 electrolysis, the catalyst layer 09 must be electrically connected to a cathode terminal. This is preferably done via the connection to the cathode end plate 04, to which the cathode terminal is connected. For this purpose, the invention provides for an electrically conductive grid 13 to be arranged within the gas diffusion layer 08. This grid 13 extends over the entire extent of the gas diffusion layer 08 and can be connected circumferentially at a plurality of free connection points 15 (see Fig. 4) to a cathode connection or indirectly to the cathode end plate 04. Furthermore, the grid 13 extends at a plurality of points to the catalyst layer 09, so that an electrically conductive connection to the catalyst layer 09 is established via a plurality of grid contact points 14. Figure 2 schematically outlines the structure of a second embodiment of an electrolysis cell 11 according to the invention. This essentially corresponds to the first embodiment shown in Figure 1, so only the additions will be discussed.

[0089] To fix the position of the gas diffusion electrode formed from the gas diffusion layer 08 and the catalyst layer 09, this example provides for the use of spacers 24, 25. Cathode-side spacers 24, integrally connected to the cathode end plate 14, are inserted in contact with the gas diffusion layer 08. Opposite, anode-side spacers 25, integrally connected to the anode end plate 15, are inserted. To prevent contact through the anode-side spacers 25, these 25 are provided with a non-conductive coating 28. Not sketched is the necessary anode and the anode membrane for separating the anode from the water chamber 07.

[0091] Figure 3 schematically depicts a grid 13 woven into a mesh. For example, the grid 13 may be formed by alternating metal threads 16 and plastic wires 17.

[0092] The shape for the grid contact points 14 is not directly shown. For this purpose, the metal threads 16 must be bent at appropriate points before being embedded in the base body 12 of the gas diffusion layer 08, so that the grid 13 extends locally to the surface on the left side 03 at a plurality of points.

[0093] Figure 4 shows a schematic diagram of the gas diffusion layer 08. This layer 08 essentially consists of the electrically non-conductive base body 12. The electrically conductive grid 13 is integrally embedded within the gas diffusion layer 08. This grid 13 extends along the outer periphery of the gas diffusion layer 08 beyond the base body 12, providing a plurality of connection points 15. On the left side 03 of the gas diffusion layer 08, the grid contact points 14 of the grid 13 are freely accessible, enabling contact with the catalyst layer 09.

Claims

Claims 1 . Electrolysis cell (01,11) for the electrolysis of CO2 with a right side (02) and a left side (03) comprising in direct or indirect sequence - a cathode end plate (04,14), - a gas chamber (06), - a gas diffusion layer (08) with an electrically non-conductive base body (12) and an electrically conductive grid (13), - a catalyst layer (09), - a water chamber (07), and - an anode end plate (05, 25); wherein the grid (13) comprises a plurality of metal threads (16) at least predominantly enclosed within the base body (12) and a plurality of grid contact points (14) electrically conductively connected to the catalyst layer (09); characterized in that the metal threads (16) of the grid (13) are sewn into the base body; or wherein the base body (12) is at least partially designed in the manner of a woven and / or braided mesh, and the metal threads (16) of the grid (13) are woven or braided into the mesh of the base body (12).

2. Electrolysis cell (01, 11) according to claim 1, wherein the grid (13) is electrically conductively connected to a cathode terminal via a plurality of connection points (15) arranged on the outer circumference of the gas diffusion layer (08) as free ends of the grid.

3. Electrolysis cell (01, 11) according to claim 1 or 2, wherein the grid (13) is electrically conductively connected to a cathode terminal via a plurality of edge contact points which are designed analogously to the grid contact points (14) and are arranged near the ends of the grid.

4. Electrolysis cell (01, 11) according to one of claims 1 to 3, wherein the grid (13) is electrically conductively connected to a cathode terminal via a plurality of connection points which are designed analogously to the grid contact points (14) and are arranged on the side opposite the cathode end plate (04, 14).

5. Electrolysis cell (01, 11) according to one of claims 1 to 4, wherein the grid (13) has a non-conductive coating with the exception of the grid contact points (14) and with the exception of connection points (15).

6. Electrolysis cell (01, 11) according to one of claims 1 to 5, wherein the grid (13) has a hydrophobic coating with the exception of the grid contact points (14) and with the exception of connection points (15).

7. Electrolysis cell (01, 11) according to one of claims 1 to 6, wherein, based on the area of ​​the catalyst layer (09), at least one grid contact point (14) is present per 500 mm2; and / or wherein, based on the area of ​​the catalyst layer (09), a maximum of one grid contact point (14) is present per 1 mm2.

8. Electrolysis cell (01, 11) according to one of claims 1 to 7, wherein, based on the area of ​​the catalyst layer (09), at least one grid contact point (14) is present every 100 mm2, in particular every 50 mm2; and / or wherein, based on the area of ​​the catalyst layer (09), a maximum of one grid contact point (14) is present every 2 mm2, in particular every 4 mm2.

9. Electrolysis cell (11) according to one of claims 1 to 8, characterized by at least one cathode-side spacer (24) which is fixed between the cathode-side cathode end plate (14) and the gas diffusion layer (08) in the gas chamber (06); and / or characterized by at least one anode-side spacer (25) which is fixed between the anode-side anode end plate (15) and the catalyst layer (09) in the water chamber (07).

10. A gas diffusion electrode for use in an electrolysis cell (11) according to one of the preceding claims, comprising a catalyst layer (09) and a gas diffusion layer (08), which (08) comprises an electrically non-conductive base body (12) and an electrically conductive grid (13), wherein the grid (13) comprises a plurality of metal threads (16) at least predominantly enclosed within the base body (12) and a plurality of grid contact points (14), which (14) are electrically conductively connected to the catalyst layer (09); characterized in that the metal threads (16) of the grid (13) are sewn into the base body; or wherein the base body (12) is at least partially designed in the manner of a woven and / or braided mesh and the metal threads (16) of the grid (13) are woven or braided into the mesh of the base body (12).

Images