Electrode material and electrode for distribution of working medium in fuel cell

Abstract

An electrode material (1) for a fuel cell (50) comprises a plate-like body (11) consisting of an electrically conductive foam having an open porosity through which at least one working medium of the fuel cell (50) can pass, wherein the plate-like body (11) has an upper side (12) and an underside (13), wherein the thickness (14) of the material measured between a point (12a, 12a') on the surface of the upper side (12) and a point (13a, 13a') on the surface of the underside (13) opposite to the point (12a, 12a') varies by at least 10% over the range of all points (12a, 12a') on the surface of the upper side (12). An electrode (2) for a fuel cell (50), comprising a plate-like body (21) consisting of an electrically conductive foam with an open and permeable porosity for at least one working medium of the fuel cell (50), wherein the plate-like body (21) has an upper side (22) and an underside (23), wherein the upper side (22) and / or the underside (23) have regions (22a, 23a) in which the porosity of the plate-like body (11) is reduced by at least 10%. A fuel cell (50) having an electrode (2). A method for producing the same.

Description

Technical Field

[0001] The invention relates to an electrode for distributing at least one operating medium of a fuel cell, as well as an electrode material, a method for producing the electrode and a fuel cell having the electrode. Background Art

[0002] In a fuel cell, the fuel present in the anode chamber reacts with the oxidant present in the cathode chamber via the electrolyte. The electrolyte is only ion-conducting and does not contain free electrons that could drive an electric current through an external load.

[0003] In order to achieve an optimized energy density for the current generation, it is important that the fuel and the oxidant are distributed uniformly over the entire surface of the electrolyte. For a rough distribution, a distribution structure is introduced in the bipolar plate or end plate, which adjoins the anode chamber or cathode chamber on the side facing away from the electrolyte. A porous gas diffusion layer adjoins the distribution structure as an electrode structure. DE 10 2016 213 057 A1 discloses an example for a fuel cell in which the bipolar plate contains a complex distribution structure. Summary of the invention

[0004] In the context of the present invention, an electrode material for a fuel cell has been developed. The electrode material comprises a plate-like body made of an electrically conductive foam, which has an open porosity through which at least one working medium of the fuel cell can pass. The plate-like body has an upper side and an underside. The thickness of the material, measured between a point on the surface of the upper side and a point on the surface of the underside opposite to the point, varies by at least 10% over all points on the surface of the upper side.

[0005] It is known that a large-space distribution structure for the working medium can be introduced into the electrode material by adjusting the porosity of the foam. This means that the manufactured electrode is continuously composed of a conductive foam, and the porosity of the foam is different locally. The area with reduced porosity can especially cooperate with the end plate or bipolar plate to form a distribution structure for the working medium. Here, the functionality of the distribution structure can be distributed in any way on the one hand to the area with reduced porosity and on the other hand to the end plate or bipolar plate. In this way, for example, the function of the distribution structure integrated into the end plate or bipolar plate can be promoted by the area with reduced porosity. But the area with reduced porosity can also cooperate with the flat surface of the end plate or bipolar plate, for example.

[0006] The formation of the distribution structure with the participation of regions with reduced porosity certainly has the advantage that the distribution is made uniform. In particular, all regions of the distribution structure are easily accessible to the working medium. Distribution by means of open-cell foam can be achieved with low pressure losses, and the porosity also allows for the lateral exchange of locally different pressure losses. In particular, the extent in the plane in the flow direction through the foam structure can have a ratio of, for example, between 0.2 to 1 and 5 to 1 to the circumference of the cross section through which the flow passes.

[0007] It has been relatively expensive to produce metal foams, especially with a porosity that varies locally at certain locations. Standard processes for foaming macroscopic blocks with a size of a few decimeters in one go result in any regular structure. Additive manufacturing methods, such as 3D printing, require relatively more time.

[0008] It is known that electrode materials with varying thickness can be used in order to produce electrodes with locally varying porosity in a particularly simple manner. If, for example, an electrode material with local elevations is compressed or rolled to a desired thickness, the material contained in the elevations must then go somewhere. This material can only be transferred into the interior of the foam by locally squeezing the foam there. This local squeezing simultaneously locally reduces the porosity.

[0009] The thickness of the material varies here by at most 50% over all points on the surface of the top side. It is then also ensured that the electrode produced from the electrode material is at least approximately still permeable for the working medium in the region with reduced porosity.

[0010] For this reason, the porosity of the foam, even in the state not yet subjected to pressure treatment, is advantageously between 40% and 80%.

[0011] The upper side of the disk cut out of the foam block can run, for example, in a wedge-shaped manner toward the lower side, and / or the lower side can run in a wedge-shaped manner toward the upper side. When the electrode material is compressed or rolled into an electrode, an electrode with a stable gradient of porosity is produced.

[0012] In a particularly advantageous configuration, the upper side and / or the lower side have elongated projections and / or depressions which define a channel-like structure on the upper side or the lower side. When such a structured electrode material is rolled or compressed into an electrode, the working medium then moves inside the finished electrode, preferably inside the channel-like structure. The flow is "blocked" at the boundary surface with the region with reduced porosity. As a result, the flow in the plane of the plate-shaped electrode can also be diverted perpendicularly to this plane.

[0013] At the same time, the areas with reduced porosity, such as those produced when the protrusions are pressed, cannot be completely passed through by the working medium, but always contribute to the distribution of the working medium. Thus, for example, a uniform supply of electrolyte adjacent to the electrode produced in this way is ensured. The gas distribution structure in the end plate or bipolar plate is of course located in a gas-tight material, which allows the flow of the working medium only inside the distribution structure and completely prohibits it at other locations. Therefore, a gas diffusion layer is usually required between such a gas distribution structure and the electrolyte.

[0014] The electrode material allows the function of a macroscopic distribution structure and the function of a microscopic gas diffusion layer to be combined in the same electrode, so that a fuel cell having such an electrode can be manufactured thinner. This increases the power density of the fuel cell. This is particularly important when a plurality of fuel cells are connected to form a stack in order to generate an increased voltage or an increased current.

[0015] As explained above, the advantages of the variable porosity in the electrode can be brought about in particular by the electrode material, which brings about this variable porosity after compression into the finished electrode. However, physically, the advantageous effect of the variable porosity is only limited by the fact that the porosity is completely variable, which can always be influenced in this way. Thus, for example, interruptions in the speed of 3D printing can be brought about, so that the general teaching given here, namely the local variation of the porosity of the electrode for the fuel cell, can also be used in additive manufacturing as economically as it is now by compression or rolling of the foam.

[0016] The invention therefore generally relates to an electrode for a fuel cell. The electrode comprises a plate-like body made of an electrically conductive foam having an open and penetrable porosity for at least one working medium of the fuel cell. The plate-like body has an upper side and a lower side. The upper side and / or the lower side have regions in which the porosity of the plate-like body is reduced by at least 10%.

[0017] As described above, the porosity is advantageously reduced by deformation. This is particularly evident in the finished electrode, since, for example, the webs with the generally stable curvature change that form the porosity bubbles are significantly stretched, compressed, bent or even broken by the deformation relative to their general length that can be seen from the rest of the material.

[0018] Advantageously, the porosity in the region with reduced porosity decreases by a maximum of 50%. As explained above, all regions of the electrode are still sufficiently permeable to the working medium.

[0019] Advantageously, the area with reduced porosity is limited to the channel-like structure in the upper side or the lower side. In this way, it is possible in particular to distribute the working medium supplied only at limited locations over the entire area of ​​the electrolyte and thus also spatially homogenize the power output of the fuel cell.

[0020] In a further advantageous embodiment, the channel structure transitions into a material recess in the upper surface and / or in the lower surface. Ideally, the material recess runs essentially parallel to the channel structure. The material recess forms a region in which the working medium for the fuel cell undergoes only negligible pressure losses when passing through the conductive foam. If the electrode is used in a fuel cell, energy for compressing the working medium can thus be saved and the overall efficiency of the fuel cell can be increased.

[0021] Here, the material recess is advantageously arranged in the side of the electrode facing away from the side containing the area with reduced porosity. If the area with reduced porosity is present in the upper side of the electrode, the material recess is present in the lower side of the electrode, and vice versa. The electrode can be arranged in a fuel cell, for example, so that the side containing the area with reduced porosity faces the electrolyte, while the side with the material recess faces the bipolar plate or the end plate. The working medium supplied in the area of ​​the bipolar plate or the end plate can first be freely distributed along the material recess. On its path to the electrolyte, an increasing flow resistance is obtained, while at the same time maintaining the entire area of ​​the electrolyte for the working medium.

[0022] Advantageously, the material recess reaches a maximum depth which is between 10% and 40% of the maximum material thickness of the electrode. This represents an optimal compromise between, on the one hand, the largest possible flow cross section for the working medium and, on the other hand, maintaining the highest possible stability of the electrode material.

[0023] In another advantageous configuration, the porosity increases or decreases monotonically along at least one direction of the upper surface or along the lower surface. This variation of the porosity can also be used to homogenize the final conversion of the working medium on the electrolyte. If, for example, the working medium is supplied via a supply line at the left edge of the plate-shaped electrode, the porosity there can be relatively low, whereby the largest part of the working medium continues to move to the right and then also reaches the electrolyte there. At the right edge of the plate-shaped electrode, however, there is a working medium with a reduced pressure, and the electrode can penetrate relatively easily in the direction of the electrolyte.

[0024] According to the above, the electrode is advantageously produced by pressing and / or rolling the electrode material. It is clearly visible on the finished electrode whether the electrode has been produced in this way.

[0025] The pressing can be advantageously performed, for example, by pressing between a flat first pressing surface and a topologically structured second pressing surface. The rolling can be performed, for example, between a purely cylindrical first roller and a second roller which is also cylindrical but topologically structured on its cylindrical circumference. Here, the topologically structured portion of the second pressing surface or the second roller corresponds to the material recess. Here, "corresponding" is understood in particular to mean that the topologically structured portion predetermines the position where the material recess exists, and the profile of the material recess that finally appears completely corresponds to the profile of the topologically structured portion. Since the conductive foam of the electrode material has a certain elasticity, the electrode material can partially rebound after the topologically structured portion is pressed in, so that the material recess in the final state is not as deep as at the time of pressing in, for example.

[0026] The material recess can also be produced in any other way, for example by removal with a laser beam. However, pressing and rolling the topological structure are advantageous because the required changes compared to previous pressing or rolling are particularly simple and cost-effective to implement. Removal with a laser beam has the advantage that the remaining material is not compressed.

[0027] Advantageously, the average pore size of the electrode material or the finished electrode is between 100 μm and 400 μm at least in some regions. The lower limit ensures that the pressure loss of the working medium is not too great. The upper limit ensures that the working medium is still distributed sufficiently finely on the surface of the electrolyte.

[0028] According to the above, the present invention also relates to a fuel cell having an anode chamber, a cathode chamber and an electrolyte, which separates the anode chamber from the cathode chamber. The anode chamber and the cathode chamber are delimited on the side facing away from the electrolyte by an end plate or a bipolar plate. The electrodes described above are arranged between at least one end plate or a bipolar plate on the one hand and the electrolyte on the other hand, so that the end plate or the bipolar plate cooperates with the region of the electrode with reduced porosity to form a distribution structure for at least one working medium of the fuel cell. As explained above, this also has the effect that the fuel cell can be constructed thinner overall.

[0029] According to the above, the end plate or bipolar plate can additionally cooperate with the material recesses of the electrode to form a distributor structure in order to reduce the pressure loss of the working medium. The pressure loss is determined in principle by the flow cross section presented to the working medium in combination with the resistance of the structure through which the working medium is to pass. With typical dimensions of the material recesses, the pressure loss can be reduced by approximately half compared to a state in which the working medium must constantly pass through the conductive foam.

[0030] The invention also relates to a method for producing the electrode material. In the method, a plate-like body is cut from a block of conductive foam. A linear cutting tool is moved through the block in a monotonous basic motion. A thickness variation is introduced in that the movement of the cutting tool perpendicular to the basic motion is modulated onto the basic motion.

[0031] In this context, a linear cutting tool is understood in particular to be a cutting tool that has at least one linear cutting edge, wherein in a given position, the movement of the cutting tool along a basic movement through the block in a direction perpendicular to the basic movement can not change the part of the material that is located behind along the basic movement, that is, has already been cut, and is also not hindered by said part. Thus, for example, the filament always interacts with the block only in its current position along the basic movement and continues to cut along a line, which is obtained by the superposition of the basic movement and the modulated movement. The expanding saw blade, for example, collides with the edge on the side wall of the gap that is opposite to the cutting edge when it is completely located in the gap cut by the saw blade for the first time in the interior of the block. The saw blade cannot be tilted arbitrarily to change the direction in which the cutting of the block is continued. If cutting is carried out by means of an electric current by means of a linear cutting tool, this is known per se as the term linear erosion.

[0032] It is known that electrode material can be produced quickly and cost-effectively in this way on a macroscopic scale and in large layers on a structured portion of local thickness. In particular, a structured portion which can extend laterally through the entire electrode and serve as a channel-like structure for conducting a working medium can be produced simply, for example by means of a wire extending through the entire block.

[0033] The block in which the conductive foam is present typically has a size of 20 cm x 30 cm x 1 m. The plate-like body of the electrode material can have a thickness between 0.5 mm and 3 mm, for example. Therefore, a plurality of plate-like bodies can be cut from one block. Advantageously, the edge material is minimized so as not to waste unnecessary material. For this purpose, it is advantageous to alternately implement a complete cutting through the block by means of a modulated basic movement, i.e., by means of a cutting surface that not only runs in the direction of the basic movement, and a complete cutting through the block by means of a non-tempered basic movement, i.e., by means of a cutting surface that runs in the plane in the direction of the basic movement. When the electrode material is processed into a finished electrode, for example, by pressing or rolling, the flat cutting surface can be used, for example, as a support surface for the electrode material. The non-flat cutting surface provides a structure that is pressed into the material, for example, during pressing or rolling. Each part cut from the block can be used as a plate-like body of the electrode material. The abrasive particles generated only at the corresponding cutting edges appear in the waste.

[0034] The invention also relates to a further method for producing the electrode from the electrode material. In the method, the electrode material is at least temporarily compressed by a minimum of 20% and a maximum of 60% with respect to its thickness.

[0035] It is known that during compression in this region, the porosity within the electrode changes to such an extent that a flow of the working medium can be guided within the electrode, while at the same time open porosity remains throughout the electrode and no region is completely excluded from the supply of the working medium. As already mentioned, the electrode can fulfill the dual function of distribution structure and diffusion layer for the working medium particularly well.

[0036] It is taken into account here that the electrode material partially springs back again after the compressive force is relieved, ie the deformation is partially plastic and partially elastic.

[0037] Advantageously, the electrode material is subjected to a compression load of 200 N / cm 2 and 3000N / cm 2 The load is significantly more than 150N / cm 2 The typical pressing of the electrode produced is subjected to the pressing during the usual compression in a fuel cell or a fuel cell stack. The linear pressing in this area leads to at least partial plastic deformation of the electrode material without completely closing or destroying many pores here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Further measures for improving the present invention are described in detail below in conjunction with the description of preferred embodiments of the present invention with reference to the accompanying drawings.

[0039] The accompanying drawings show:

[0040] FIG. 1 is an embodiment of an electrode material 1;

[0041] FIG. 2 shows an embodiment of an electrode 2 which is obtained by compression or rolling of the electrode material 1 shown in FIG. 1 ;

[0042] Figure 3 An embodiment of an electrode 2 having two different levels of reduced porosity;

[0043] Figure 4 Exemplary production of a body 11 of electrode material 1 from a block 1 a of conductive foam;

[0044] FIG5 : Exemplary manufacture of multiple bodies 11 , 11 ′ with minimal material loss;

[0045] Figure 6 Embodiment of a fuel cell 50 having an exemplary electrode 2 . DETAILED DESCRIPTION

[0046] Figure 1aA first embodiment of an electrode material 1 is shown in a schematic cross-sectional view. A plate-shaped body 11 of the electrode material 1 has an upper side 12 and an underside 13. The underside 13 is flat and the upper side 12 is corrugated. The thickness 14 of the material measured between a point 12a or 12a' on the upper side 12 and a point 13a or 13a' on the underside 13 opposite to the point 12a or 12a' is changed due to the structuring. That is, there are elevations 15 and, in this example, depressions 16 in the upper side 12 of the electrode material 1.

[0047] Figure 1b A second exemplary embodiment of an electrode material 1 is shown in a schematic sectional view. Here again, the underside 13 of the plate-like body 11 is flat, while the upper side 12 runs in a wedge-shaped manner toward the underside 13. The thickness 14 of the plate-like body 11 thus decreases continuously from left to right.

[0048] Figure 2a and 2b A first exemplary embodiment of an electrode 2 is shown, which is obtained, for example, by compression or rolling of the electrode material 1 shown in FIG. 1 . Figure 2a A schematic top view is shown, Figure 2b A schematic cross-sectional view is shown.

[0049] The electrode 2 has a plate-shaped body 21, which is produced, for example, by at least partially plastic deformation of the plate-shaped body 11 of the electrode material 1. The plate-shaped body 21 has a top side 22 and a Figure 2a The bottom side 23 is not visible in the electrode material 1. Figure 1a The projections 15 visible in the figure become regions 22a with reduced porosity in the upper side 22 after compression, since the material contained in the projections 15 must be transferred inwards into the body 21. These regions 22a resist the flow of the working medium for the fuel cell 50 with increased flow resistance. The intermediate spaces between these regions 22a define a channel-like structure 24 in the upper side 22. During operation of the fuel cell 50, the plate-shaped body 21 of the electrode 2 in these regions 24 can no longer receive the working medium and transport it faster than in the regions 22a. Figure 2b , a material recess 26 is also shown, into which the channel-like structure 24 transitions. In this case, the material recess 26 is present in the underside 23 of the electrode, ie, in the side of the electrode 2 facing away from the region 22a with reduced porosity.

[0050] Figure 2c A second embodiment of the electrode 2 is shown, which is achieved by Figure 1bThe compression or rolling of the electrode material 1 shown in FIG. 1 is obtained. Here, the force effect is evenly distributed on the upper side 12 and the lower side 13 of the plate-shaped body 11 of the electrode material 1. Therefore, the plate-shaped body 21 of the electrode 2 obtained in this way includes a region 22a or 23a with reduced porosity on its upper side 22 and its lower side 23. By determining how much material must be transferred to the interior, it is determined how deep the region reaches into the interior of the plate-shaped body 21. In this way, for example, during compression or rolling, Figure 1b The wedge 11 of the electrode material 1 shown in FIG. Figure 2c As can be seen in the trend, regions 22a and 23a extend deeper into the body 21 of the formed electrode 2 at the left edge than at the right edge. In addition, within regions 22a and 23a, the exact value of the porosity increases monotonically from left to right along direction 25.

[0051] Figure 3 A third embodiment of an electrode 2 is shown in a schematic cross-sectional view. The electrode 2 can be obtained, for example, by: Figure 1a Two bodies 11 of electrode material 1 of the type shown in FIG. 1 and having projections 15 on their upper sides 12 are placed one above the other, more precisely twisted by 90° relative to one another, and the assembly is subsequently rolled or compressed. Then all projections 15 are similar to those from Figure 1a Transition to Figure 2a and 2b This is converted into a region 22a with reduced porosity, the difference being that there are horizontal and vertical such regions 22a. However, the most qualitatively important difference is the conversion of the intersection of the elevations 15 in the region 22a' into a region with a more strongly reduced porosity.

[0052] When the electrode 2 to be manufactured is as in Figure 3 If the conductive foam is rectangular and non-square, as shown in FIG. 2 , two bodies 11 can be produced, for example, with the same rectangular dimensions with the projections 15, but with an orientation offset by 90° relative to one another, by cutting a piece from the conductive foam alternately in different directions. If the cuts are carried out alternately with an identical and regular modulation offset by 90° relative to one another, a disk is formed, the upper and lower sides of which have projections 15 offset by 90° relative to one another. Again, a body structured on both sides is formed, as in FIG. Figure 3 As shown in .

[0053] Suitable variants can be produced, for example, for a rhombus-shaped flow field in which there are rhombus-shaped areas of greater and lesser porosity by virtue of the cuts for producing the modulation of the upper and lower sides of the foam disk being carried out at angles between 0° and 90° relative to one another.

[0054] Regions 22 a ′ with a more greatly reduced porosity can be used, for example, in a fuel cell 50 in order to achieve regular locations for homogenizing the local reaction rate, at which water condenses in a targeted manner, to conduct heat or to generate mechanical support points.

[0055] Figure 4 It is shown by way of example how a body 11 of electrode material 1 can be produced from a block 1a of conductive foam. A linear cutting tool 3 extending perpendicularly to the image plane is guided from top to bottom through the block 1a with a basic movement 31. Based on this basic movement 31, a movement 32 perpendicular to the basic movement is modulated. By means of this additional movement 32, as in Figure 1a The raised portions 15 and recessed portions 16 visible in the Figure 2b The wedge shape visible in FIG. 1 is introduced into the body 11. Figure 4 In the example shown in , the raised portion 15 of the cut body 11 corresponds to the recessed portion 16 in the surface of the remaining block 1a, and the recessed portion 16 of the cut body 11 corresponds to the raised portion 15 in the surface of the remaining block 1a. Thus, the pre-processing for producing the next body 11 is already completed, and the next body can be cut from the block 1a in the next working step.

[0056] FIG. 5 shows, by way of example, how a plurality of bodies 11 , 11 ′ of electrode material 1 can be produced from a block 1 a of electrically conductive foam with minimal material losses. Figure 5a shows how the block 1a can be divided into Figure 1a A plurality of similar bodies 11 , 11 ′ of the type shown in FIG. Figure 5b It is shown how the block 1 a can be divided into a plurality of similar bodies 11 , 11 ′ by an alternating sequence of two differently inclined cuts, the upper and lower sides of which each taper toward one another.

[0057] Figure 6 An exemplary embodiment of a fuel cell 50 is shown. The fuel cell 50 has an anode chamber 50a and a cathode chamber 50b, which are separated from one another by an electrolyte 53. The anode chamber 50a is bounded on the one hand by a first end plate 51 and on the other hand by an electrolyte 53. The cathode chamber 50b is bounded on the one hand by a second end plate 52 and on the other hand by an electrolyte 53. Figure 6 For reasons of clarity, lateral or circumferential seals are not shown.

[0058] A sample of the electrode 2 is arranged in each of the anode chamber 50a and the cathode chamber 50b, wherein the electrode 2 is arranged according to Figure 2b The respective channel-like structure 24 outside the region of reduced porosity 22 a interacts with the respective end plate 51 or 52 to form a distribution structure 54 or 55 for the working medium of the fuel cell 50 .

[0059] Similar to Figure 2c , where the channel-like structure 24 transitions into material recesses 26 of the electrode 2. Here, these material recesses 26 each face the end plates 51, 52 and extend perpendicularly to the image plane, parallel to the channel-like structure 24. The working medium supplied in the region of the end plates 51, 52 can initially be distributed with a small pressure loss over the entire boundary surface between the end plates 51, 52 and the electrode 2 adjacent to the end plates. When the working medium moves within the image plane in the direction of the electrolyte 53, an increasing flow resistance results from the material recesses.

Claims

1. An electrode (2) for a fuel cell (50), comprising a plate-like body (21) consisting of an electrically conductive foam having an open and permeable porosity for at least one working medium of the fuel cell (50), wherein: The plate-like body (21) has an upper side (22) and a lower side (23), wherein the upper side (22) and / or the lower side (23) have regions in which the porosity of the plate-like body (21) is reduced by at least 10% relative to intermediate spaces between the regions, wherein the intermediate spaces are arranged alternately with the regions, wherein the intermediate spaces define a channel-like structure (24) between the regions in the upper side (22) or the lower side (23), wherein the channel-like structure can transport the working medium faster than the regions, wherein the channel-like structure (24) transitions into a material recess (26) in the surface of the upper side (22) and / or in the surface of the lower side (23), wherein the material recess (26) is arranged in that side of the electrode (2) which faces away from the side containing the region with reduced porosity, wherein the material recess (26) is located completely between the regions.

2. The electrode (2) according to claim 1, wherein: The porosity in the region with reduced porosity is reduced by deformation.

3. The electrode (2) according to claim 1 or 2, wherein: In the region with reduced porosity, the porosity decreases by a maximum of 50%.

4. The electrode (2) according to claim 1 or 2, wherein: The material recess (26) reaches a maximum depth which is between 10% and 40% of the maximum material thickness of the electrode (2).

5. The electrode (2) according to claim 1 or 2, wherein the electrode is produced by pressing and / or rolling the electrode material (1), wherein: The thickness (14) of the electrode material (1) measured between a point (12a, 12a') on the upper surface and a point (13a, 13a') on the lower surface opposite the point (12a, 12a') varies by at least 10% over all points (12a, 12a') on the upper surface.

6. The electrode (2) according to claim 5, wherein the electrode is produced by pressing the electrode material (1) between a flat first pressing surface and a topologically structured second pressing surface, or by rolling between a cylindrical first roller and a second roller with a topological structure on its cylindrical circumference, wherein: The topological structuring of the second pressing surface or of the second roller corresponds to the material recess (26).

7. The electrode (2) according to claim 1 or 2, wherein: The average pore size, at least in some regions, is between 100 μm and 400 μm.

8. A fuel cell (50) comprising an anode chamber (50a), a cathode chamber (50b) and an electrolyte (53), the electrolyte separating the anode chamber (50a) from the cathode chamber (50b), wherein: The anode chamber (50a) and the cathode chamber (50b) are respectively delimited on the side facing away from the electrolyte (53) by end plates or bipolar plates (51, 52), wherein an electrode (2) according to any one of claims 1 to 7 is arranged between at least one end plate or bipolar plate (51, 52) on the one hand and the electrolyte (53) on the other hand, so that the end plate or bipolar plate (51, 52) cooperates with the region of the electrode (2) with reduced porosity to form a distribution structure (54, 55) for at least one working medium of the fuel cell (50).

9. The fuel cell (50) according to claim 8, wherein: The end plates or bipolar plates (51, 52) additionally interact with the material recesses (26) of the electrodes (2) to form the distribution structures (54, 55).

10. A method for producing an electrode (2) according to any one of claims 1 to 7 from an electrode material (1), wherein: The electrode material (1) is at least temporarily compressed by at least 20% and at most 60% in terms of its thickness.

11. The method according to claim 10, wherein: The electrode material (1) is designed to have a compressive load of 200 N / cm 2 and 3000N / cm 2 The suppression between.

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