Electrolytic cell having optimised contacting of a catalyst layer
Patent Information
- Application Number
- AE202602642
- Authority / Receiving Office
- AE · AE
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-02-12
- Filing Date
- 2025-01-27
Smart Images
Figure ABST_ABST
Abstract
Description
DescriptionTITLEElectrolytic cell having optimised contacting of a catalyst layerTECHNICAL FIELD
[0001] The invention relates to an electrolysis cell for electrolysis of CO2. This electrolysis cell has a gas chamber containing CO2 and a water chamber containing an electrolyte, which are separated from one another by a gas diffusion layer and a catalyst layer. This requires contacting of the catalyst layer.BACKGROUND
[0002] Renewable power, such as solar and wind energy, can be made available at some locations to an extent that exceeds local demand. It is a problem in this case to effectively utilize the available power. One option is electrolysis of water to hydrogen and oxygen. However, storage and transport of hydrogen are problematic. It is also known that the available renewable power can be utilized by an electrochemical conversion of CO2, and the greenhouse gas CO2 can be bound as product. The electrochemical reduction reaction of carbon dioxide (CO2) to hydrocarbons by CO2 electrolysis constitutes a promising alternative to other energy storage strategies.
[0003] Reduction of CO2 is accomplished using electrolysis cells. On one side there is an anode which is separated from a liquid electrolyte by a membrane. In the electrolysis cell is the cathode, which is in contact with the CO2 to be reduced. Given appropriate voltage between the anode and the cathode, electrolysis of the CO2 takes place. For this purpose, in the electrolysis cell as regularly used, a cavity for receiving the electrolyte is positioned adjacent to the cathode on the side facing the anode. On the opposite side is a cavity for receiving the CO2, where the cavities are separated from one another by a gas diffusion electrode.
[0004] The general mode of operation of an electrolysis cell for electrolysis of CO2 is sufficiently well known to those skilled in the art. This is described, for example, in WO2023 / 217624A1 or WO2019 / 096985A1.
[0005] It has been found to be advantageous when the gas diffusion electrode is formed by a non-conductive gas diffusion layer and a conductive catalyst layer. This requires contacting of the catalyst layer.
[0006] The catalyst layer is generally contacted at the circumferential edge of the catalyst layer, for example by means of applied copper strips. If the extent of the electrolysis cell is small, a sufficiently uniform voltage distribution over the area of the catalyst layer can be achieved.
[0007] A problem is the limited conductivity of the catalyst layer and the low layer thickness typically used for the catalyst layer. In conjunction with the need to provide an area of the catalyst layer sufficient for practical application, it is not immediately possible to ensure a sufficient and in particular uniform voltage between the catalyst layer and the anode.
[0008] In order to solve the problem, it is proposed in known embodiments that a conductive mesh, for example of copper, be positioned on the catalyst layer opposite the gas diffusion layer, i.e. on the anode side in the electrolyte.
[0009] However, this arrangement has several disadvantages. On the one hand, the placing of the conductive mesh in the electrolyte can have an adverse effect on the electrochemical process. Also unfavorable is the smaller distance of the anode from the conductive mesh in relation to the distance of the anode from the catalyst layer. Furthermore, the effective area of the catalyst layer is reduced by the mesh.SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide a voltage of maximum uniformity over the area of the catalyst layer. At the same time, the effective area of the catalyst layer available should be at a maximum.
[0011] The object is achieved by an embodiment of the invention according to the teaching of claim 1. Advantageous embodiments are the subject matter of the dependent claims.
[0012] An electrolysis cell for electrolysis of CO2 has, in direct or indirect succession, 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 main body and an electrically conductive mesh, where the mesh is positioned at least for the most part within the main body. The catalyst layer is contacted via a multitude of mesh contact points.DESCRIPTION OF THE INVENTION
[0014] The generic electrolysis cell serves as intended for electrolysis of CO2 and comprises, in direct or indirect succession,–a cathode end plate,a gas chamber,a gas diffusion layer,a catalyst layer,a water chamber, andan anode endplate.
[0015] For further description, reference is made to a left-hand side where the anode endplate is present, and to an opposite, right-hand side. The terms "left-hand side" and "right-hand side" are chosen arbitrarily in this respect; however, the terms should always be understood hereinafter to mean that the left-hand side relates to that side on which the anode end plate is present, while the right-hand side is correspondingly the opposite side of the electrolysis cell.
[0016] The cathode end plate and the anode end plate are the geometric terminus of the respective electrolysis cell. In the case of an arrangement of a plurality of electrolysis cells, a cathode end plate of an electrolysis cell may simultaneously form the anode end plate of the subsequent electrolysis cell.
[0017] The gas chamber is a cavity in the electrolysis cell, which is supplied as intended with CO2 in operation of the electrolysis cell. The water chamber is a further cavity which is intended to contain an electrolyte in operation of the electrolysis cell.
[0018] The gas diffusion layer together with the catalyst layer form a gas diffusion electrode. This separates the gas chamber from the water chamber. It is functionally necessary here for the gas diffusion layer to be permeable to CO2, but to prevent the passage of liquid through the gas diffusion electrode.
[0019] First of all, a starting point for the invention is the assumption that the gas diffusion layer is an electrically non-conductive layer. For this purpose, the latter has, as an essential element, a main body made of an electrically non-conductive material.
[0020] In contrast, the catalyst layer is particularly advantageously electrically conductive. For this purpose, the catalyst layer consists of an electrically conductive material or has at least one electrically conductive coating.
[0021] The catalyst layer here forms the cathode of the electrolysis cell.
[0022] In addition, it is possible for the catalyst layer or the gas diffusion layer itself to be of multilayer design. With regard to the possible and advantageous layer structures, reference is made to the known prior art.
[0023] It is obvious that the gas chamber and the gas diffusion layer and the catalyst layer and the water chamber advantageously have to be sealed circumferentially in order to be able to realize the gas chamber and the water chamber as cavities. It is also obvious that corresponding connections are necessary for introducing and discharging fluids into and out of the gas chamber or water chamber.
[0024] In a simple and at the same time advantageous manner, the gas chamber directly adjoins the cathode end plate.
[0025] It is particularly advantageous when the gas diffusion layer adjoins the gas chamber directly.
[0026] Effective CO2 electrolysis can be achieved when the catalyst layer directly adjoins the gas diffusion layer.
[0027] It is particularly advantageous when the water chamber adjoins the catalyst layer directly.
[0028] In any case, an anode is required. In this case, in one embodiment, it may be the case that the anode end plate simultaneously forms the anode of the electrolysis cell. In an alternative embodiment, an anode is positioned indirectly or preferably directly adjacent to the anode end plate.
[0029] It is particularly advantageous when the water chamber is separated from the anode by an anode membrane and, in this respect, the anode membrane directly adjoins the water chamber.
[0030] It may be the case here that an anode chamber is positioned between the anode membrane and the anode. However, direct contact of the anode membrane with the anode is preferred.
[0031] It is functionally necessary for a voltage to be applicable to the electrolysis cell. It is particularly advantageous here when the power connection to the electrolysis cell is on the left-hand side on the anode end plate and on the opposite right-hand side on the cathode end plate.
[0032] Alternatively, it may likewise be the case that the anode and / or the catalyst layer as cathode are contacted to the outside, separately from the anode end plate or cathode end plate.
[0033] For achievement of maximum uniformity of voltage distribution at the catalyst layer, it is the case that there is electrical contacting of the catalyst layer at a plurality of points. In this case, however, the known positioning of an electrically conductive mesh in the water chamber is dispensed with.
[0034] In contrast, it is the case that an electrically conductive mesh is positioned within the gas diffusion layer. However, it should be taken into account that the gas diffusion layer must first and foremost be electrically non-conductive. It is thus necessary to form the gas diffusion layer from an electrically non-conductive main body, with an electrically conductive mesh being arranged at least for the most part within the main body.
[0035] The thickness and distribution of the mesh may be chosen differently. It is at least the case here that the mesh makes up only the smaller portion of the volume of the gas diffusion layer in relation to the main body. Thus, the diffusion of the CO2 is not unnecessarily impeded. It has to be ensured here that the mesh has the necessary electrical conductivity.
[0036] The gas diffusion layer thus comprises an electrically non-conductive main body and an electrically conductive mesh, where the volume of the mesh is preferably not more than 0.25 times the volume of the main body. The volume of the mesh is particularly preferably smaller than 0.15 times the volume of the main body.
[0037] Furthermore, it is necessary in accordance with the invention that the mesh on the left-hand side adjacent to the catalyst layer at a multitude of points leads to the surface of the gas diffusion layer, so that contacting of the catalyst layer becomes possible at a multitude of mesh contact points. In other words, an electrically conductive connection to the catalyst layer is established via the mesh contact points.
[0038] The mesh may take a variety of forms. It is not necessary here for the mesh to be entirely within the main body. It is assumed here that at least half of the mesh (or of the volume thereof) is within the main body.
[0039] However, it is advantageous when at least 2 / 3 of the volume of the mesh is within the main body. The mesh is particularly advantageously essentially completely within the main body, although it is obvious that the mesh must be exposed, i.e. not enclosed by the main body, at the mesh contact points and at further points for indirect contacting with a cathode terminal.
[0040] By means of this embodiment, the flow of current to the catalyst layer is distributed over many mesh contact points, and hence the supply of current into the area of the catalyst layer is not restricted to the connection at the outer edge of the catalyst layer. This permits flexible dimensioning of the electrolysis cell and eliminates the restriction to small structural sizes.
[0041] The arrangement of the electrically conductive mesh in the gas diffusion layer eliminates the need for a conductive mesh in the water chamber and hence in the electrolyte.
[0042] It is also the case here that the mesh comprises a plurality of metal filaments, which are enclosed here at least mainly within the main body. It is accordingly the case that the mesh is integrally embedded in the gas diffusion layer. In other words, the mesh is fixed inseparably in the main body of the gas diffusion layer.
[0043] A particularly advantageous weave of the metal filaments within the gas diffusion layer can be achieved by two different solutions according to the invention, both solutions being based on incorporation of the metal filaments into the main body.
[0044] In a first variant of the invention, it is assumed that the main body consists at least partly of a single-layer or multilayer woven or entwined network of non-conductive plastic filaments.The mesh here is likewise formed in the manner of a network, i.e. the metal filaments are likewise woven or entwined to form the mesh.
[0045] In the case of a network-like design, it is necessary to combine metal filaments of the mesh with the network of the main body in order to achieve the advantageous weave in the gas diffusion layer, so as to form an intrinsically more stable network with integrated mesh. In this respect, the metal filaments of the mesh should be woven or entwined into the network of the main body.
[0046] In principle, it is sufficient to guide a plurality of metal filaments through a network of the main body only in an essentially mutually parallel direction in order to form the mesh. In this regard, "essentially" relates to the fact that the metal filaments pass through the main body effectively in parallel in a common direction.
[0047] In addition, a further advantageous execution for formation of the electrically conductive mesh may be chosen, in which a plurality of first metal filaments are guided in a first direction in a network of the main body, with a plurality of second metal filaments guided in a second direction, for example transverse to the first direction, for example traversing another layer of a network of the main body. First and foremost, it is not the case here that the first metal filaments and the second metal filaments are interwoven, intertwined or otherwise bonded to one another - but the metal filaments in each case are woven or entwined within the respective network of plastic filaments.
[0048] For production, it may be the case that the network is first produced from non-conductive plastic filaments and then the metal filaments are intertwined or interwoven.
[0049] However, it is particularly advantageous when the metal filaments are interwoven or intertwined into the network of non-conductive plastic filaments directly in the production of at least one network of the main body. In this case, the plastic filaments and the metal filaments are in an alternating arrangement in the network.
[0050] It may further be the case that a network comprising the electrically conductive mesh and non-conductive plastic filaments is combined with another network consisting solely of non-conductive plastic filaments.
[0051] Alternatively, in a second variant of the invention, it may be the case that the mesh, analogously to the previous variant, comprises a plurality of metal filaments, but these are sewn into the main body.
[0052] In this case, the main body is first produced from a non-conductive material, or at least one layer of the main body, and then the metal filaments are sewn into the main body or the layer of the main body. In this case, the main body or the layer of the main body may likewise be constructed as a network of plastic filaments, as in the previous embodiment. Likewise possible here, however, is execution as a foamed body, for example.
[0053] The density and the distribution of the metal filaments and of the non-conductive plastic filaments can advantageously be determined on the basis of the necessary cross sections and the chosen manufacturing method.
[0054] In an obvious and advantageous manner, the circumferential edge of the catalyst layer can be electrically contacted without reduction, such that the edge region of the catalyst layer is supplied with voltage.
[0055] The electrically conductive connection of the mesh within the gas diffusion electrode to a cathode terminal is preferably effected at the circumferential outer periphery of the gas diffusion electrode via a multitude of connection sites, i.e. at respective individual free ends of the mesh.
[0056] It may be the case here that the connection sites are distributed over the outer circumference outside the main body. It may also be the case that the main body is removed in sections for exposure of the connection sites.
[0057] In a second contacting variant, a plurality of edge contact points on the mesh are used. In this case, the edge contact points are designed to correspond to the mesh contact points, i.e. to be likewise arranged on the surface of the main body on the left-hand side facing toward the catalyst layer. For contacting, for example, a conductive layer - copper strip - may be placed on the peripheral edge of the gas diffusion layer, so that contacting at the edge contact points is enabled.
[0058] In a third contacting variant, the mesh is provided with a plurality of connection points. These may be of analogous design to the mesh contact points, but have to be in an opposite arrangement on the side facing the gas chamber. Contacting of the mesh is thus possible via the plurality of connection points, and the current can be transferred to the catalyst layer in a distributed manner via the multitude of mesh contact points.
[0059] It is obvious that it is possible to combine the three different types of contacting.
[0060] In any case, it is necessary that the mesh extends at a multitude of points up to the surface on the left-hand side and hence implements the mesh contact points. Contacting of the catalyst layer is thus enabled at the mesh contact points.
[0061] If there are no mesh contact points in the immediate area on account of the design and / or the production process, it may advantageously be the case that the gas diffusion layer is processed, for example ground off, on the left-hand side, such that contact at the mesh contact points can be assured.
[0062] In order to ensure long-lasting stability without impairment of the electrolysis, it may be advantageous to provide the mesh with a non-conductive coating. It is obvious that the mesh contact points and connection points must be exposed here for contacting.
[0063] In order to avoid adhesion of any substances or molecules in the gas diffusion layer, it is also particularly advantageous when the electrically conductive mesh is provided with a hydrophobic coating. What is thus prevented is that particles can adhere to the mesh, which is conductive per se and has typically hydrophilic properties, no matter whether during production / assembly or during operation or standstill, and thus reduces the free permeability for CO2.
[0064] The chosen number of mesh contact points per unit area of the catalyst layer may be different. The greater the number chosen, the more uniform the voltage distribution over the area of the catalyst layer will be. However, it is necessary here to take account of the problem that, as the number of mesh contact points increases, there will be increasing complexity involved in producing the gas diffusion layer with the electrically conductive mesh.
[0065] An advantage over solutions from the prior art is enabled when there is at least one mesh contact point per 500 mm2. In order not to unnecessarily restrict the effective area of the catalyst layer, however, the density of the mesh contact points should not be greater than one mesh contact point per 1 mm2.
[0066] It has been found to be advantageous to provide at least one mesh contact point per 100 mm2, based on the area of the catalyst layer. More preferably, there is at most one mesh contact point per 50 mm2 based on the area of the catalyst layer.
[0067] By contrast, the chosen number of mesh contact points should preferably not be greater than one mesh contact point per 2 mm2. It is considered to be particularly preferable when there is a maximum of one mesh contact point per 4 mm2.
[0068] In order to assure a defined distance between the cathode end plate and the gas diffusion layer, in particular for securing the position of the gas diffusion layer and the width of the gas chamber, it is particularly advantageous when at least one cathode-side spacer is used on the right-hand side of the gas diffusion layer. It is necessary here for there to be a defined position of the cathode-side spacer between the cathode end plate and the gas diffusion layer.
[0069] The cathode-side spacer here bears against the cathode end plate and, on the opposite side, against the gas diffusion layer. It is obvious that the cathode-side spacer is within or penetrates the gas chamber. The cathode-side spacer is thus intended to ensure that the distance between the cathode end plate and the gas diffusion layer does not change owing to deformations of the gas diffusion layer.
[0070] Furthermore, depending on the dimensions of the electrolysis cell and the rigidity of the gas diffusion layer and of the catalyst layer, it may be advantageous when at least one anode-side spacer is positioned in the water chamber. It is necessary here for there to be a defined position of the anode-side spacer between the anode end plate and the catalyst layer.
[0071] The anode-side spacer is thus intended to ensure that the distance between the anode end plate and the catalyst layer does not change owing to deformations of the catalyst layer.
[0072] In conjunction with the cathode-side spacer, the position of the catalyst layer and the gas diffusion layer can be reliably determined with the anode-side spacer. It is thus possible to ensure that areal contact of the catalyst layer on the gas diffusion layer is assured.
[0073] In a first option, it may be the case that a plurality of cathode-side spacers are positioned in the gas chamber or a plurality of anode-side spacers in the water chamber. In this case, the cathode-side spacers should be fixedly connected to the cathode end plate or the anode-side spacers to the anode end plate, such that their position is fixed.
[0074] In the case of the anode-side spacers that are fixedly connected to the anode end plate, the anode has to be designed so as to surround the spacers. It may be the case here that the anode membrane is likewise designed to surround the spacers. If the shaping of the anode membrane makes it possible, covering of the anode and the spacers is preferably undertaken with the anode membrane.
[0075] In a second option, it may be the case 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 between the anode end plate and the catalyst layer in the water chamber.
[0076] The preferred execution uses integral cathode-side spacers fastened to the cathode end plate and a one-piece, mounted anode-side spacer positioned in the water chamber. There are thus no restrictions or extra expenses for the design of the anode and the anode membrane.
[0077] For assurance of minimum hindrance of flow in the gas chamber or water chamber, a one-piece mounted spacer should be designed in the form of a mesh. The covered area of the gas diffusion layer and of the catalyst layer here should be at a minimum, and the spacer in mesh form should otherwise be spaced apart from the cathode end plate or anode end plate and in particular from the gas diffusion layer or the catalyst layer.BRIEF DESCRIPTION OF THE DRAWINGS
[0078] FIG. 1 shows a schematic section of a first working example for the construction of an electrolysis cell of the invention with an electrically conductive mesh positioned within the non-conductive gas diffusion layer.
[0079] FIG 2 shows a schematic section of a second working example for the construction of an electrolysis cell of the invention which is analogous to the first working example, where the position of the gas diffusion electrode is fixed by spacers.
[0080] FIG. 3 shows a schematic of the possible shape for a mesh that can be embedded in the gas diffusion layer.
[0081] FIG. 4 shows a schematic of a gas diffusion layer with an integrated conductive mesh.DESCRIPTION OF THE EMBODIMENTS
[0082] Figure 1 shows a first working example of an electrolysis cell 01 of the invention. This simplified diagram shows the structure of the electrolysis cell 01 in the sequence from the right-hand side 02 to the left-hand side 03.
[0083] The cathode end plate 04 is on the right-hand side 02. Typically, the cathode-side current connection is made to the cathode end plate 04. The gas chamber 06 is adjacent to the cathode end plate 04. In operation of the electrolysis cell 01, the gas chamber is supplied with the carbon dioxide (CO2) to be converted.
[0084] On the left-hand side 03 is the anode end plate 05. As intended, the anode-side current connection is preferably effected on the left-hand side at the anode end plate 05. The water chamber 07 is shown in the figure adjacent to the anode end plate 05. In implementation, it should be taken into account that the anode is located at or forms the anode end plate 05. In order to realize the electrolysis cell, the anode should in turn be separated from the water chamber 07 by an anode membrane. In operation of the electrolysis cell 01, the electrolyte for enabling electrolysis is 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. In this case, the gas diffusion layer 08 is electrically non-conductive and, by contrast, the catalyst layer 09 is electrically conductive.
[0086] In order to enable CO2 electrolysis, it is necessary to electrically connect the catalyst layer 09 to a cathode terminal. This is preferably effected via the connection to the cathode end plate 04, to which in turn the cathode terminal is connected.
[0087] For this purpose, according to the invention, an electrically conductive mesh 13 is positioned within the gas diffusion layer 08. This 13 extends over the whole extent of the gas diffusion layer 08 and may be connected to a cathode terminal or indirectly to the cathode end plate 04 in a circumferential manner at a multitude of free connection sites 15 (see fig. 4). Furthermore, the mesh 13 extends as far as the catalyst layer 09 at a multitude of sites, such that an electrically conductive connection to the catalyst layer 09 is established via a multitude of mesh contact points 14.
[0088] Figure 2 shows a schematic of the construction of a second working example of an electrolysis cell 11 of the invention. This corresponds essentially to the first working example from figure 1, and so only the additions will be discussed.
[0089] The position of the gas diffusion electrode formed from the gas diffusion layer 08 and the catalyst layer 09 is fixed in this example by using spacers 24, 25. This involves using cathode-side spacers 24 integrally connected to the cathode end plate 14 and bearing against the gas diffusion layer 08. On the opposite side, anode-side spacers 25 integrally connected to the anode end plate 15 are used. In order to prevent contacting by the anode-side spacers 25, these 25 are provided with a non-conductive coating 28.
[0090] The necessary anode and the anode membrane for separation of the anode from the water chamber 07 are not shown.
[0091] Figure 3 is a schematic of a mesh 13 woven 13 to form a network. It may be the case here, for example, that the mesh 13 is formed alternately by metal filaments 16 and plastic wires 17.
[0092] The shaping for the mesh contact points 14 is not illustrated directly. For this purpose, the metal filaments 16 have to be bent at appropriate sites before being embedded into the main body 12 of the gas diffusion layer 08, such that the mesh 13 extends locally to the surface on the left-hand side 03 at a multitude of sites.
[0093] Figure 4 shows a schematic of a the gas diffusion layer 08. This 08 consists essentially of the electrically non-conductive main body 12. Within the gas diffusion layer 08 is the integrally embedded electrically conductive mesh 13. This 13 extends beyond the outer circumference of the gas diffusion layer 08 up to the main body 12, such that a multitude of connection sites 15 are available. On the left-hand side 03 of the gas diffusion layer 08, the mesh contact points 14 of the mesh 13 are freely accessible, such that contacting of the catalyst layer 09 is enabled.
Claims
1. An electrolysis cell (01, 11) for electrolysis of CO2, having a right-hand side (02) and a left-hand side (03), comprising, in direct or indirect succession,a cathode end plate (04, 14),a gas chamber (06),a gas diffusion layer (08) having an electrically non-conductive main body (12) and an electrically conductive mesh (13),a catalyst layer (09),a water chamber (07), andan anode end plate (05, 25); where the mesh (13) comprises a plurality of metal filaments (16) enclosed at least mainly within the main body (12), and a multitude of mesh contact points (14) electrically conductively connected to the catalyst layer (09);characterized in thatthe metal filaments (16) of the mesh (13) are sewn into the main body; orwhere the main body (12) at least partly takes the form of a woven and / or entwined mesh and the metal filaments (16) of the mesh (13) are woven or entwined in the mesh of the main body (12). 2. The electrolysis cell (01, 11) as claimed in claim 1,wherein the mesh (13) is electrically conductively connected to a cathode terminal via a multitude of connection sites (15) on the outer circumference of the gas diffusion layer (08) as free ends of the mesh. 3. The electrolysis cell (01, 11) as claimed in claim 1 or 2,wherein the mesh (13) is electrically conductively connected to a cathode terminal via a plurality of edge contact points that are of analogous design to the mesh contact points (14) and are positioned close to the ends of the mesh. 4. The electrolysis cell (01, 11) as claimed in any of claims 1 to 3,wherein the mesh (13) is electrically conductively connected to a cathode terminal via a plurality of connection points, which are of analogous design to the mesh contact points (14) and are positioned on the opposite side to the cathode end plate (04, 14). 5. The electrolysis cell (01, 11) as claimed in any of claims 1 to 4,wherein the mesh (13) has a non-conductive coating with the exception of the mesh contact points (14) and with the exception of connection points (15). 6. The electrolysis cell (01, 11) as claimed in any of claims 1 to 5,wherein the mesh (13) has a hydrophobic coating with the exception of the mesh contact points (14) and with the exception of connection points (15). 7. The electrolysis cell (01, 11) as claimed in any of claims 1 to 6,wherein, based on the area of the catalyst layer (09), there is at least one mesh contact point (14) per 500 mm2; and / orwherein, based on the area of the catalyst layer (09), there is at most one mesh contact point (14) per 1 mm2. 8. The electrolysis cell (01, 11) as claimed in any of claims 1 to 7,wherein, based on the area of the catalyst layer (09), there is at least one mesh contact point (14) for every 100 mm2, in particular every 50 mm2; and / orwherein, based on the area of the catalyst layer (09), there is at most one mesh contact point (14) per 2 mm2, especially per 4 mm2. 9. The electrolysis cell (11) as claimed in any of claims 1 to 8,characterized by at least one cathode-side spacer (24) which (24) is fixed in the gas chamber (06) between the cathode-side cathode end plate (14) and the gas diffusion layer (08); and / or characterized by at least one anode-side spacer (25) which (25) is fixed in the water chamber (07) between the anode-side anode end plate (15) and the catalyst layer (09). 10. A gas diffusion electrode for use in an electrolysis cell (11) as claimed in any of the preceding claims,comprising a catalyst layer (09) and a gas diffusion layer (08) which (08) comprises an electrically non-conductive main body (12) and an electrically conductive mesh (13), where the mesh (13) comprises a plurality of metal filaments (16) enclosed at least mainly within the main body (12) and a multitude of mesh contact points (14) which (14) are electrically conductively connected to the catalyst layer (09);characterized in thatthe metal filaments (16) of the mesh (13) are sewn into the main body; orwhere the main body (12) at least partly takes the form of a woven and / or entwined mesh and the metal filaments (16) of the mesh (13) are woven or entwined in the mesh of the main body (12).