EP4330446A1

EP4330446A1 - Gas diffusion layer for an electrochemical cell and electrochemical cell

Info

Publication number: EP4330446A1
Application number: EP22717156.8A
Authority: EP
Inventors: Simon Kießlich; Alexander Spies
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2021-05-31
Filing date: 2022-03-23
Publication date: 2024-03-06
Also published as: CN117413092A; WO2022253476A1; EP4098773A1; CA3221783A1; AU2022285042A1

Abstract

The invention relates to a gas diffusion layer (50) for an electrochemical cell (90), having a contacting unit (10) and a metal unit (12) which is arranged at or on the contacting unit (10). With respect to a main surface (30) with a defined thickness (d), the metal unit (12) has a plurality of projections (14) which are substantially perpendicular to the main surface (30). At least one opening (16) is formed on at least one side surface (15) or top surface (13) of the plurality of projections (14) of the metal unit (12). Each elongation (18) of the plurality of projections (14) is at least three times the thickness (d) of the metal unit (12).

Description

description

Gas diffusion layer for an electrochemical cell and electrochemical cell

The invention relates to a gas diffusion layer for an electrochemical cell and an electrochemical cell. The electrochemical cell can be, for example, a fuel cell or an electrolytic cell.

In electrolytic cells, such as a PEM electrolytic cell, gas diffusion layers are often used inside the cell. The gas diffusion layer fulfills various ferent tasks. On the one hand, electrical contacting of a membrane to a bipolar plate should be made possible. In addition, any process media that arise, such as hydrogen or oxygen, should be reliably discharged. Other process media, such as water, should be fed in at the same time. Therefore, in addition to a certain porosity, a gas diffusion layer must also have mechanical, electrical and topological properties that can fulfill the aforementioned tasks.

Although current gas diffusion layers are available, they are usually very expensive. In the case of sintered discs, for example, a graduated surface is usually required. For this purpose, powders are often pressed together, sintered and/or fused together. This attempts to optimally set a size or property of the sintered disc for the gas diffusion layer. Complex thermal treatment is often necessary in order to produce a suitable gas diffusion layer. Because of this effort, there is a need for a more efficient and, above all, more cost-effective production of a gas diffusion layer. Current electrolysis cells are not yet designed for a larger scale. This means in particular that such electrolytic cells should produce outputs in the kilowatt or megawatt range. Especially with electrolytic cells, which, for example, for should be suitable for air traffic, a corresponding dimensioning of such electrolytic cells quickly results. In the high-performance range in particular, the aspect of cost-effectiveness in electrolytic cells comes to the fore. In order to be able to sensibly operate such electrolytic cells, in particular PEM electrolytic cells (PEM = Proton Exchange Membrane), the purchase price per kilowatt output must fall significantly. To do this, it is necessary to keep an eye out for potential cost reductions for all the necessary components. This is hardly possible with the current structures.

Patent specification EP 3140 434 B1 describes a gas diffusion layer and an electrochemical cell with such a gas diffusion layer. The gas diffusion layer serves to attach between a bipolar plate and an electrode of an electrochemical cell. At least two layers layered on top of each other are designed as a progressive spring characteristic. Although a controlled flow of process media can be made possible with such a gas diffusion layer, it is not possible to improve the economics of electrolytic cells to a sufficient extent.

The published application DE 102017 130 489 A1 relates to a bipolar plate for a fuel cell. The fuel cell includes a corrugated plate having a pattern of holes consisting of at least a first row of holes and a second plate sealingly attached to the corrugated plate. The corrugated plate is formed from a metal sheet and has a regular waveform of rising and falling waves. No specific information is given with regard to a gas diffusion layer. The gas diffusion layer is shown as a simple rectangular layer.

One object of the invention can be seen in the production of components for electrochemical cells more economically. place. In particular, it should be possible to manufacture high-performance electrochemical cells more cheaply or increase their cost-effectiveness.

This problem is addressed by this invention with the independent claims of this application. Alternative and sensible embodiments are given in the dependent claims, the description and the figures.

The invention provides a gas diffusion layer for an electrochemical cell, which has a contacting unit and a metal unit. The metal unit is arranged on or on the contacting unit. In particular, the metal unit can be arranged directly on or on the contacting unit. The metal unit has a plurality of elevations substantially perpendicular to the base with respect to a planar base of predetermined thickness. The planar base may be part of the metal unit. The metal unit can thus be formed from the flat base. The metal unit may be stamped and/or stamped sheet metal.

However, it is also possible that the planar base represents a projected plane along a normal direction. For example, in the case of a corrugated, v-shaped or w-shaped metal plate, a flat support surface, such as a flat table surface, can represent the flat base surface. In such a case, the planar base is not part of the metal unit. Preferably, the planar base is part of the metal unit. The metal unit can thus include the flat base or has the flat base.

In particular, with respect to the planar base with a predetermined thickness, the metal unit includes a plurality of elevations substantially perpendicular to the base. The term "substantially perpendicular" can mean that deviations from 90 degrees are also possible. "Substantially perpendicular". can in particular comprise an angle of 75 to 110° from the respective elevation to the base area.

At least one opening is formed on at least one side face or surface of the plurality of bumps of the metal unit. In this case, a respective extension of the several elevations is in particular at least three times the thickness of the metal unit. The respective extent of the plurality of elevations perpendicular to the metal unit or perpendicular to the planar base is at least three times the thickness of the metal unit. This respective extent is preferably a vertical distance, vertical distance, vertical height, or vertical dimension of elevation to the base or metal unit. The elevation can also have a longitudinal extent and a transverse extent. The longitudinal extension is in particular an extension of the elevation parallel to the base area. The transverse extension is in particular also an extension of the survey parallel to the base area, but perpendicular to the longitudinal extension. The respective extent of the plurality of elevations is preferably a vertical distance between the elevation and the flat base of the metal unit or a vertical dimension of the respective elevation that protrudes from the flat base of the metal unit.

The opening can be a bore or a hole. The opening can be formed as a recess which allows gas to pass through the metal unit. In particular, the opening or the plurality of openings can allow gas transport from a first side of the metal unit to an opposite second side of the metal unit. The respective extent of the plurality of elevations can be four times, five times, six times, seven times, eight times, nine times or more than ten times the thickness of the metal unit. The thickness of the metal unit preferably refers to the planar base area of the metal unit. The metal unit can be formed as a metal sheet. In particular, the metal unit can be designed as a semi-finished product. A semi-finished product can in particular mean a preliminary material, which can be a prefabricated raw material, workpiece or semi-finished product. Simple profiles, rods, tubes, plates or sheet metal can be regarded as semi-finished products. Such semi-finished product variants can each be formed as a metal unit. The metal unit can be, for example, a metal sheet with a thickness of 1 to 5 mm.

The openings result in particular from the at least one elevation. The opening can be arranged on a side surface of this elevation and/or on a front surface of this elevation. Permeability normal to the plane of the sheet can be influenced with this. A metal sheet is preferably used as the metal unit, since this is particularly cost-effective. The at least one elevation is preferably a slot bridge perforation. A metal sheet with a slotted bridge hole can be obtained, for example, by a stamping process. The contacting layer is arranged in particular on the side of the metal unit that faces away from the elevations. In this way, a gas diffusion layer for an electrochemical cell can be created at low cost.

An additional or alternative embodiment provides that an arrangement of the several elevations and their respective extensions are determined in such a way that the metal unit together with the contacting unit form a spring component which has a degressive spring characteristic. The arrangement of the several elevations and their respective expansions can in particular include a number and position of the associated openings. In particular, the openings do not separate the bumps from the metal unit. For example, the elevations can be cylindrical, triangular or cuboid. A mixture of different geometric shapes with regard to the elevations is also possible. The respective arrangement and extent of the surveys including the associated openings can be determined in advance using a finite element method. Here, the slot bridge perforation has proven to be particularly efficient. At the same time, the slotted bridge perforation can be produced inexpensively. The slotted bridge perforation can be characterized in particular by an elongated elevation. It can be described as an alternating zipper pattern. Each slotted bridge stands out from a base area of the sheet metal. At the same time, there is an opening in the area of the slot bridge perforation, which allows gas to be transported through the metal unit. The arrangement and the respective extent of the elevations can preferably be determined in such a way that as little waste as possible is produced on the metal unit when the gas diffusion layer is produced. A punching process is therefore preferred, as there is no waste here.

An additional or alternative embodiment relates to a gas diffusion layer, wherein all respective elevations have substantially the same extent. "Essentially the same extent" can mean in particular that the smallest elevation differs from the largest elevation by a maximum of 10%. In this case, the largest elevation is preferably used as the reference variable. At the same time, it is preferably provided here that the respective elevations are of the same type, are arranged regularly and/or homogeneously. The arrangement of the several elevations thus corresponds in particular to a regular pattern. This is particularly advantageous since such elevations can be implemented using simple manufacturing processes, such as stamping processes. A stamped metal plate or a stamped metal sheet can can thus be formed into a metal unit with regular elevations.The elevations formed in this way correspond, in particular, to a stamping profile used in a stamping machine.It is thus particularly easy to create a corresponding metal unit.

An additional or alternative embodiment provides that an arrangement and/or expansion of the elevations aptly a distance between the elevations, a nature of the elevation, the extent of the elevation as a function of a predetermined parameter of the gas diffusion layer, in particular a cell thickness and/or a contact pressure of the gas diffusion layer, is determined. The extension of the bump can be viewed as a height of the bump. A cell thickness of the gas diffusion layer can be adjusted by means of a correspondingly higher elevation. Likewise, a contact pressure and a distribution of the contact pressure can be set by the arrangement and/or extent of the elevations. The elevations are preferably determined in terms of their arrangement and/or dimensions in such a way that there is a homogeneous contact pressure in the gas diffusion layer. By adapting the geometry with regard to the distance and the nature of the elevations, different cell thicknesses and homogeneity of the contact pressure can be set in a targeted manner, even at a low level of contact pressure. A porosity of the gas diffusion layer and thus the mass transport can also be influenced. With the help of the stamping process, important parameters such as the homogeneity of the contact pressure, the porosity and the cell thickness of the gas diffusion layer can be influenced in a simple and targeted manner. A simulation or a finite element method can be used to determine the arrangement and dimensions of the multiple bumps. Using simple and inexpensive methods, a less expensive and yet efficient gas diffusion layer can be created.

An additional or alternative embodiment provides that the multiple elevations and the metal units are monolithic. In particular, the multiple elevations are not separate components. They are preferably made of the same material as the metal unit. The multiple elevations and the metal unit thus form in particular a unitary or one-piece component. The plurality of bumps and the metal unit can thus be viewed as a unitary component or part. Even if Openings are arranged on a surface or the side surface of the bumps, the plurality of bumps and the metal unit can still be formed monolithically. In this case, they are made of the same material or consist of the same material. A uniform metal unit including the associated elevations can thus be created.

An additional or alternative embodiment provides that the contacting unit is designed as a fleece, metal fabric and/or carbon paper and/or the metal unit is designed as sheet metal, metal foam, metal fabric, perforated sheet metal and/or slotted bridge sheet metal. The contacting unit is used in particular for uniform contacting of the gas diffusion layer with other components of an electrochemical cell. This can be an electrode, a bipolar plate or a membrane, for example. The metal unit in the form of sheet metal can have several holes. Preferably the metal unit is a metal plate with a slotted bridge hole. A porosity of the metal unit can be increased simply and effectively by means of a slotted bridge perforation. The porosity can in particular be a quotient of the perpendicular extension of the elevation to the metal unit to an overall extension of the metal unit in the perpendicular direction. If, for example, a 1 mm thick metal plate has a vertical elevation of another 4 mm, the porosity in this case would be P = 4 mm / 5 mm = 0.8 = 80%. A metal sheet stamped in this way corresponds to a porosity of 80% within the meaning of this application. With the help of a slotted bridge perforation, the porosity of the metal unit can be adjusted particularly easily and inexpensively. In this way, a component for electrochemical cells can be produced inexpensively.

An additional or alternative embodiment provides that the metal unit has a porosity of at least 80%, which is formed by the multiple elevations of the metal unit. A higher porosity can, for example be achieved by a greater extension of the elevations perpendicular to the metal unit. Thus larger elevations can be produced by correspondingly deeper punching. Thus, the porosity of the metal unit and hence the gas diffusion layer can be increased.

The invention also relates to an electrochemical cell with a gas diffusion layer. For this purpose, the electrochemical cell can have a bipolar plate and an electrode. The gas diffusion layer is in contact with the bipolar plate on a first side and with the electrode on an opposite second side. The electrode can in turn be contacted with a membrane. Accordingly, the electrochemical cell can have a membrane. The electrochemical cell can be designed as an electrolytic cell or as a fuel cell. Due to the easy-to-manufacture gas diffusion layer, a cost-effective and at the same time efficient electrochemical cell can be created.

An additional or alternative embodiment provides that the gas diffusion layer is connected to the bipolar plate and/or the electrode in a force-fitting, form-fitting and/or cohesive manner. Thus, the gas diffusion layer can be connected to the bipolar plate and to the electrode in a wide variety of ways. The type of connection can be force-fitting, form-fitting and/or material-fitting. A non-positive connection can result, for example, by placing the respective layers on top of one another and pressing them. The form-fitting connection can result, for example, from sheathing with a metal mesh and subsequent pressing. A material connection can be created by welding the respective components. The types of connection mentioned can also be present between the gas diffusion layer and the membrane. Since the gas diffusion layer described is significantly easier and cheaper to produce, this advantage has a corresponding effect on the electrochemical cell off. In this way, an electrochemical cell that is significantly cheaper than in the past can be created. This can be helpful when implementing the energy transition.

The invention will now be explained in more detail with reference to the accompanying drawings. The drawings represent exemplary embodiments of the invention. However, the invention is not limited to the exemplary embodiments shown in the figures. It shows:

1 shows a schematic view of a gas diffusion layer with metal unit and contacting component in cross section;

2 shows an exemplary degressive spring characteristic for the gas diffusion layer;

3 shows an exemplary metal unit with a slot bridge perforation;

4 shows a bent perforated plate as a metal unit;

5: in a schematic representation, an electrochemical

cell together with the gas diffusion layer.

FIG. 1 shows an exemplary gas diffusion layer 50 in cross section. Several components of the gas diffusion layer 50 can be seen here. The contacting unit 10 can be seen in the lower area. Above this contact unit 10, the metal unit 12 with egg ner associated flat base 30 connects. The metal unit 12 has a thickness d.

Vertical elevations 14 from the metal unit 12 can be seen in FIG. These elevations 14 each have Seitenflä surfaces 15 and 13 surfaces. Openings 16 are preferably present or arranged in the area of the side surfaces 15 and surfaces 13 . A respective extent 18 of these surveys Gen 14 are greater than the thickness d of the metal unit 12. The extension 18 can exceed the thickness d of the metal unit 12 by at least three times, four times, five times, six times, seven times, eight times, nine times and ten times.

In the example in FIG. 1, the plurality of elevations 14 are in the form of columns. However, the elevations 14 can also be at an angle to the base 30 of the metal unit 12. In particular, an oblique angle can be assumed here. In the left-hand area of FIG. 1, an inclined elevation 14 is indicated by dashed lines. However, vertical elevations 14 are preferably used. Perpendicular can also mean "substantially perpendicular", which in turn can include an angle of 75 to 110°. In FIG. 1, an oblique angle is indicated left elevation 14 is indicated.

In this case, an elevation 14 can have one or more openings 16 . These openings 16 are located in particular on the side faces 15 of the elevations 14 and/or on the upper surface 13 of the elevations 14. It is also possible for all elevations 14 to have openings 16. The openings 16 are preferably arranged on the respective side faces 15 of the elevations 14 . However, the openings 16 can also be arranged on the upper surface 13 of the elevation 14 . The surface 13 of the respective elevation 14 faces away from the metal unit 12 in particular. The openings 16, which can be seen in FIG. 1, are each arranged on the side faces 15 of the elevations 14. FIG. The surface 13 of the elevation 14 follows in the direction perpendicular to the base area 30 of the metal unit 12 .

A core concept of this invention is the use of a structure in which bridges, webs, semicircles or similar elevations are stamped and embossed from the sheet metal in one manufacturing step. These surveys are preferred not separated from the sheet 12. The elevations 14 shown in FIG. 1 can thus be designed as bridges, webs, semicircles or similar elevations. The openings 16 enable a material or gas transport from one side of the sheet 12 to an opposite side of the sheet 12.

The first side of the metal unit 12 is arranged on the contacting element 10 in FIG.

The second side of the metal unit 12 contains the multiple elevations 14. The gas diffusion layer 50 shown in FIG. 1 is produced in particular by a stamping process. There is no waste, which can lead to corresponding cost advantages. A slot bridge perforation is preferably used. The shape and arrangement of the several elevations 14 can also be created by a nostril hole or slit arc hole. A porous and electrically conductive layer can be created with mechanical spring retention.

By adapting the geometry with regard to the distance and the nature of the elevations 14, different cell thicknesses and a homogeneity of the contact pressure can be set in a targeted manner, even at a low level. As a result, the porosity of the metal unit 12 or the gas diffusion layer 50 and thus the possibility of mass transport can be influenced in a simple and targeted manner. If the pressure level in the region of the gas diffusion layer 50 changes, larger or smaller gas bubbles can result. The porosity of the metal unit 12 and of the gas diffusion layer 50 can be dependent, in particular, on predetermined pressure conditions in electrochemical cells. Thus, an extent, arrangement and/or shape of the plurality of elevations 14 can depend on an operating pressure of an electrochemical cell 90 .

With a classic perforated plate as the metal unit 12, mass transport normal to the plane of the plate is already possible. To one To produce the appropriate porosity of the perforated sheet, the perforated sheet is embossed or deep-drawn without separating the structure of the perforated sheet. In this way, porosity can be made possible with regard to the transport of the process media parallel to the plane of the sheet. This is possible, for example, by regular mutual folding or by a wavy embossing of the sheet. Such a process can be chosen when stamping should not or cannot be used.

Using the structure described in FIG. 1 as a gas diffusion layer 50 or a gas diffusion electrode is conceivable, but the use of these structures as a spring layer of a gas diffusion layer composite structure is more likely.

In this context, FIG. 2 shows an example of a degressive spring characteristic 20. The gas diffusion layer 50 has in particular the property of the degressive spring characteristic 20. A spring deflection is marked with s on an x-axis and a pressure is marked with p on the y-axis. You can clearly see that the spring deflection s hardly changes with an increasing pressure p. The gas diffusion layer 50 has before given to a spring behavior which corresponds to the declining spring characteristic 20 . This means in particular that the gas diffusion layer 50 becomes softer as the pressure ratios p increase. The degressive spring characteristic 20 relates in particular to the metal unit 12. In this case, the metal unit 12 can also be referred to as a spring layer. The spring layer with the associated po rosity can be combined with a fleece.

The fleece is in particular the contacting unit 10. The contacting unit 10 can be designed as a fleece, carbon paper, metal foam, perforated sheet metal, metal fabric and/or as a finely executable structure for contacting the electrode or membrane. In an electrochemical cell 90, these mentioned contact structures can be non-positively, positively be connected to the metal unit 12 in a cohesive and/or cohesive manner. Thus, the contacting unit 10 can be connected to the metal unit 12 in a force-fitting, form-fitting and/or cohesive manner. The same can apply to a connection between the gas diffusion layer 50 and other components of the electrochemical cell 90, such as the bipolar plate or the electrode or the membrane. The electrochemical cell 90 can be a fuel cell 90 or an electrolytic cell 90 .

Due to the simplified structure of the gas diffusion layer 50, there are cost advantages in its respective production due to the smaller number of process steps. For example, an expanded sheet metal composite made up of many layers has to be connected in many steps. The number of process steps in a gas diffusion layer 50 shown as an example in FIG. 1 can thus be significantly reduced.

3 shows an example of a metal unit 12 with a slot bridge perforation. The several elevations 14 that protrude perpendicularly from the base area 30 are clearly visible. The vertical elevations 14 have a longitudinal extent 17 and a transverse extent 19 on the surface 13 . In the example in FIG. 3, the longitudinal extension 17 is greater than the transverse extension 19. In the example of the slotted bridge perforation in FIG. The extent 18 of the multiple Elevations gene 14 denotes a measure of the vertical elevation 14. At the same time in the region of the side surfaces 15 of the multiple surveys 14 He each openings 16 are arranged. However, these openings 16 are difficult to see in FIG. They still exist.

The multiple elevations 14 shown in FIG. 3 represent a type of zipper pattern. In principle, the multiple elevations 14 can differ from one another in terms of their arrangement, size and/or extent. is preferred However, a uniform or homogeneous structure is selected with regard to the plurality of elevations 14 in order to produce an efficient gas diffusion layer 50 as inexpensively as possible.

FIG. 4 shows an alternative embodiment for the metal unit 12 of the gas diffusion layer 50. Here the metal unit 12 is designed as a folded perforated plate. The flat base 30 is de facto no longer IN ANY in FIG. The bent perforated plate results from a deformation of a flat metal plate 12 as an imaginary base area 30 for the example in FIG. 4. This previously flat metal plate 12 is indicated schematically in FIG. In the case of FIG. 4, this deformation results in a V-shaped or wave-like pattern with respect to the metal plate 12. The folded perforated plate 12 shown in FIG. 4 can be described by a repeating V-profile.

Those V-edges which are arranged in the lower area on the indicated base area 30 correspond to the metal unit 12. This is indicated by a dashed line in FIG. In the case of FIG. 4, the metal unit 12 consists of several lines parallel to one another. The remainder of the bent perforated plate corresponds to the several elevations 14. The example in FIG. 4 is an extreme case of FIG. 3. The metal unit 12 in the example in FIG. 4 contains only several lines which are in contact with the originally flat perforated plate. In the case of FIG. 4, the remainder of the folded perforated plate represents the multiple elevations 14.

A height of these several elevations 14 (V-shaped elevation) is preferably at least three times the thickness of the original perforated sheet. That area of the folded perforated plate that stands out from the original plane of the perforated plate can thus be counted towards the elevation 14 . It can be provided here that a minimum amount of elevation 14 must be present in order to allow easier or better arrangement of the folded perforated plate for elevation 14 or for metal unit 12 . As can be clearly seen in FIG. is know, include the V-profiles, so the multiple elevations 14, numerous openings 16. This allows a corre sponding gas exchange can be made possible.

FIG. 5 shows the electrochemical cell 90 together with the gas diffusion layer 50 as an example and in a schematic representation. The electrochemical cell 90 can be designed as a fuel cell 90 or as an electrolysis cell 90 . Due to the gas diffusion layer 50 shown here, low specific costs per square meter can be achieved in comparison to previous products with the same function. This results in particular from simpler production or a combination of simple individual parts. At the same time, the gas diffusion layer 50 enables simple adaptation to the technical needs of new cell generations. This can be done by simple appropriate geometry adjustments. Depending on the requirement, a corresponding new stamping profile can be selected for a new geometry, for example. This new punched profile can be used accordingly in a manufacturing process for the production of appropriately fitted metal units 12 . The manufacture or use of the metal units 12 shown here can also be easily implemented for large cell areas in the square meter range. In this way, an improved tolerance compensation capability can be achieved. There is also the possibility of using elasto-plastic spring behavior in the gas diffusion layer 50 or the electrochemical cell 90.

Claims

patent claims

Having a gas diffusion layer (50) for an electrochemical cell (90).

- a contacting unit (10) and

- A metal unit (12) which is arranged on or on the contacting unit (10), wherein

- The metal unit (12) has a plurality of elevations (14) essentially perpendicular to the base area (30) with respect to a flat base area (30) with a predetermined thickness (d),

- At least one opening (16) is formed on at least one side surface (15) or surface (13) of the plurality of elevations (14) of the metal unit (12) and a respective extension (18) of the plurality of elevations (14) perpendicular to the metal unit (12) or perpendicular to the planar base (30) is at least three times the thickness (d) of the metal unit (12).

Second gas diffusion layer (50) according to claim 1, wherein an arrangement of the plurality of elevations (14) and their respective extents (18) are determined so that the metal unit

(12) together with the contacting unit (10) form a spring component which has a degressive spring characteristic (20).

3. Gas diffusion layer (50) according to any one of the preceding claims, wherein all of the respective elevations (14) have substantially the same extent (18).

4. Gas diffusion layer (50) according to any one of the preceding claims, wherein an arrangement and / or extent of the elevations (14) relating to a distance between the elevations (14) to one another, a condition of the elevation (14), the expansion (18) the elevation (18) depending on a given parameter of the gas diffusion layer (50), in particular a cell thickness and / or contact pressure of the gas diffusion layer (50) is determined.

5. The gas diffusion layer (50) of any preceding claim, wherein the plurality of bumps (14) and the metal unit (12) are monolithic.

6. Gas diffusion layer (50) according to one of the preceding claims, wherein the contacting unit (10) is designed as a fleece and/or the metal unit (12) is designed as sheet metal, metal foam, metal mesh, perforated sheet metal and/or slot bridge sheet metal.

7. A gas diffusion layer (50) according to any one of the preceding claims, wherein the metal unit (12) is a metal plate with a slotted bridge hole.

8. Gas diffusion layer (50) according to any one of the preceding claims, wherein the metal unit (12) has a porosity of at least 80%, which is formed by the plurality of bumps gene (14) of the metal unit (12).

9. Electrochemical cell (90) with a gas diffusion layer (50) according to any one of the preceding claims further aufwei send:

- a bipolar plate,

- An electrode, wherein the gas diffusion layer (50) is contacted on egg ner first side with the bipolar plate and on an opposite second side with the electrode.

10. The electrochemical cell (90) according to claim 9, wherein the gas diffusion layer (50) is connected to the bipolar plate and/or the electrode in a non-positive, positive and/or material-locking manner.