Distributor arrangement for distributing operating media in an electrolysis system, and production thereof

Abstract

The presented invention relates to a distributor arrangement (100) for distributing operating media in an electrolysis system (101), wherein the distributor arrangement (100) comprises: - a first transport layer (101) which consists at least in part of a carbon-containing material, - and a second transport layer (103) which consists at least in part of a titanium-containing material, wherein the first transport layer (101) has a thickness of between 100 µm and 2000 µm and the second transport layer (103) has a thickness of between 200 µm and 1000 µm.

Description

[0001] Description

[0002] title

[0003] Distributor arrangement for distributing operating media in a and their

[0004] The presented invention relates to a distributor arrangement for distributing operating media in an electrolysis system and a manufacturing method for producing a distributor arrangement for distributing operating media in an electrolysis system and a cell for a cell stack of an electrolysis system according to the appended claims.

[0005] State of the art

[0006] It is known that on the anode side of a PEM electrolysis cell of a

[0007] Apart from a catalyst layer, PEM electrolysis stacks primarily use titanium-based materials. This applies to porous transport layers (PTLs), which typically consist of sintered titanium particles and / or titanium fibers and / or titanium chips, as well as to flow distribution structures, such as expanded titanium metals or other open-pore structures, and to a separating plate between an anode of one cell and a cathode of a neighboring cell in an electrolysis stack, which is also referred to as a bipolar plate.

[0008] A flow distributor structure can be embossed into the separating plate, e.g. in the form of channels, the negative of which simultaneously forms a flow distributor structure of the cathode.

[0009] Titanium-based materials are used in an anode because it is typically assumed that electrochemical potentials (compared to NHE) of > 1.3 V are present throughout the anode during electrolysis operation, at which graphite-based materials or stainless steels are not corrosion-resistant.

[0010] In addition, precious metal coatings such as gold or platinum group metals such as platinum or iridium are used as corrosion protection coatings due to their intrinsic high electrical conductivity and electrochemical stability within the operating window in order to minimize the formation of titanium dioxide over the operating period.

[0011] Since titanium-based materials and their standard coatings are extremely expensive and very difficult to process, e.g. due to very high tool wear when stamping titanium sheets, an at least partial replacement of titanium and electrically conductive corrosion protection layers with other materials is desirable in order to be able to produce PEM energy converters more cost-efficiently.

[0012] Disclosure of the invention

[0013] Within the scope of the invention presented, a distributor assembly, a manufacturing method, and a cell for a cell stack of an electrolysis system are presented. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the manufacturing method according to the invention naturally also apply in connection with the distributor assembly according to the invention or the cell according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0014] The invention presented serves in particular to provide a possibility for the cost-efficient production of an electrolysis system.

[0015] Thus, according to a first aspect of the invention, a distributor assembly for distributing operating media in an electrolysis system is presented. The distributor assembly comprises a first transport layer, which consists at least partially of a carbon-containing material, and a second transport layer, which consists at least partially of a titanium-containing material. The first transport layer is between 100 μm and 2000 μm thick, and the second transport layer is between 200 μm and 1000 μm thick.

[0016] The presented invention is based on a distributor arrangement for distributing operating media in an electrolysis system, which comprises several layers, namely a first transport layer which consists at least partially of carbon-containing material, in particular graphite-containing material, and a second transport layer which consists at least partially of a titanium-containing material.

[0017] The two layers mentioned are at least partially bonded together and form a unit which is particularly mechanically stable or rigid and can therefore be easily further processed, e.g., supplemented to form a cell for an energy converter.

[0018] The first transport layer is arranged on the second and, due to the material-locking connections to the second transport layer, ensures a flat material connection with reduced contact resistance, with media tightness and corrosion stability of the presented distributor arrangement.

[0019] The connection of the first transport layer to the second transport layer can in particular be materially bonded and can be provided, for example, by a friction welding process or an adhesive.

[0020] By constructing the presented distributor arrangement from a first transport layer, which consists at least partially of a carbon-containing material, and a second transport layer, which consists at least partially of a titanium-containing material, the material requirement of titanium, which is necessary to provide an electrolysis system, is minimized.

[0021] It can be provided that the thickness of the second transport layer is selected such that when using type 1 or type 2 DI water, an electrochemical potential within the second transport layer is below 1.1 V, measured against a standard hydrogen electrode.

[0022] Due to the low ion concentration and thus also proton concentration in type 1 and type 2 DI-water, the thickness of the second transport layer can be in the range between 200 pm and 500 pm for type 1 DI-water and between 500 pm and 1000 pm for type 2 DI-water.

[0023] It may be intended that the carbonaceous material contains graphite.

[0024] In particular, the first transport layer can consist of a compacted carbon or a polymer matrix filled with carbon particles, in particular graphite particles or mixtures of graphite and other carbons, such as carbon black or hard carbon. The fill level can be > 60%, preferably between 75% and 92%, particularly preferably at least 85%.

[0025] In particular, the first transport layer can be designed as a compacted layer with the same or different carbon particle sizes or particle fractions and, optionally, additionally with open porosity. The open porosity is preferably between 35 and 55%.

[0026] It can further be provided that the first transport layer has a structured surface on a side facing away from the second transport layer, which forms a conductive structure for conducting a medium.

[0027] By means of a structured surface of the first transport layer, a plurality of channels, such as water supply channels, can be formed between the first transport layer and a bipolar plate. A surface of the first transport layer facing the bipolar plate can be structured, for example, with sufficiently large channel structures between 50 pm and 1000 pm wide and with a depth of up to 850 pm. Furthermore, the first transport layer can be perforated on a side facing the second transport layer.

[0028] For example, an open, porous, planar perforated first transport layer can additionally have a channel structure perpendicular to a longitudinal axis of the first transport layer. This channel structure can consist of perforations that can be designed in any desired way, e.g., round holes that are designed, in particular, perpendicular to the flat plane of the first transport layer or at an angle deviating from the perpendicular by < 20°. The holes can preferably occupy 30% - 80% of the surface of the first transport layer and can have a diameter of between 30 pm and 500 pm. The holes can either be randomly distributed over the surface of the first transport layer or arranged in a regular pattern, e.g., at the corners of a hexagonal lattice or at the corners of a square lattice. The holes can all be the same size or different sizes.

[0029] It can further be provided that the first transport layer and / or the second transport layer is / are coated at least on one side with a carbon-containing layer, in particular a graphite layer.

[0030] In particular, at a contact surface between the first transport layer and the second transport layer, the first transport layer and / or the second transport layer can be coated with a carbon-containing layer, in particular a graphite layer, so that a carbon-carbon bond is ensured.

[0031] It can further be provided that the first transport layer comprises a porous carrier layer made of stainless steel.

[0032] A stainless steel carrier layer, on which a carbon-containing layer is arranged or into which carbon-containing particles are incorporated, in particular made of a corrosion-resistant stainless steel according to ISO 1.4404 or higher, enables particularly high mechanical strength and stability of the distributor arrangement. It can further be provided that the first transport layer comprises a porous carbon layer made of at least one material from the following list of materials: graphite foam, expanded graphite, carbon particles, hard carbon, carbon black, and / or graphite, with a binder content of the porous carbon layer being between 5% and 20% by weight.

[0033] It can further be provided that the first transport layer comprises a carbon layer made of at least one material from the following list of materials: particles of graphite, fibers of graphite, mixtures of graphite and other carbons, in particular carbon black, hard carbon and / or a polymer matrix filled with carbon particles, the filling degree of which is at least 80%.

[0034] It can further be provided that the distributor arrangement comprises a bipolar plate arranged on the first transport layer, wherein the bipolar plate has a structured surface on a side facing the first transport layer, which forms a conductive structure for conducting a medium, or the first transport layer has a structured surface on a side facing the bipolar plate, which forms a conductive structure for conducting a medium.

[0035] In a distributor arrangement comprising a bipolar plate, the first transport layer acts as an intermediate layer between the bipolar plate and the second transport layer. A conductive structure, particularly for conducting liquid water, can be configured at a boundary layer between the first transport layer and the bipolar plate.

[0036] According to a second aspect, the presented invention relates to a manufacturing method for producing a distributor arrangement for distributing operating media in an electrolysis system.

[0037] The presented manufacturing method comprises producing a first transport layer which is between 100 pm and 2000 pm thick and consists at least partially of a carbon-containing material, and arranging the first transport layer on a second transport layer which is between 200 pm and 1000 pm thick and consists at least partially of a titanium-containing material.

[0038] For example, the respective transport layer can be porous and consist of any sintered stainless steel structure, in particular fibers, chips, or spherical particles. Preferred particle sizes can be in the range between 5 pm and 2000 pm, particularly preferably in the range between 10 pm and 100 pm. The porosity of the respective transport layers can be in the range between 40% and 90%, particularly preferably in the range between 60% and 80%.

[0039] The inner surface of a respective porous transport layer can be coated with carbon, in particular graphitized carbon, which is preferably applied by means of a vacuum deposition process.

[0040] To maximize the hydrophilicity of the inner surface after graphite coating, the graphite surface can be doped with nitrogen.

[0041] It can further be provided that the production of the first transport layer comprises an extrusion process in which a number of layers are extruded from a carbon-containing substance and doped with nitrogen.

[0042] In an extrusion process, for example, layers deposited from an ink with a solvent can be produced from a slot die, with a doctor blade or with a spraying process.

[0043] Alternatively, dry extruded layers of a mixture of particles of graphite or of mixtures of graphite and other carbons, such as carbon black or hard carbon with the lowest possible binder content, can be produced by means of extrusion from a slot die, preferably between

[0044] 5 wt% and 20 wt%. Binder materials that can be used for this purpose include, for example, thermoplastics and thermosets, such as PP, PE, PET, PEN, PVDF, PTFE or thermally and UV-curable precursors. Alternatively, planar, perforated and stacked sheets or films with a thickness of between 10 μm and 500 μm, particularly preferably between 50 μm and 250 μm, can be provided. The perforation can be designed as randomly shaped holes, for example round, which are particularly perpendicular to the sheet or film plane or at an angle deviating from the vertical film plane by < 20°. The holes preferably take up 30 - 80% of the sheet or film surface and preferably have a diameter of between 30 μm and 500 μm. The holes can either be randomly distributed over the surface or arranged in a regular pattern, e.g.at the corners of a hexagonal grid or at the corners of a square grid. The holes can be all the same size or different sizes. The sheets or foils are coated with carbon, especially graphitized carbon, which is preferably applied using a vacuum deposition process.

[0045] It can further be provided that the production of the first transport layer comprises a forming process in which the first transport layer is formed such that it has a structured surface which forms a conductive structure for conducting a medium.

[0046] Formed perforated sheets or foils can themselves have a perforation and / or the formation itself can be provided in the form of a guide structure, such as a channel or web. The guide structure can be arranged perpendicular to the flow distribution structure of the sheet or foil and have a size of between 30 pm and 1000 pm.

[0047] Alternatively, the guide structure can be designed in the form of a regularly embossed wave structure, wherein a depth of embossments is preferably the same and these are either arranged in a regular grid or run irregularly.

[0048] Regularly structured conductive structures, for example in the form of an egg carton structure, i.e. in the form of round or polygonal truncated cones, result in particularly high compressive strength. Preferred structural sizes here are between 50 pm and 2000 pm, particularly preferably in the range between 100 pm and 500 pm.

[0049] In particular, a sheet or foil can be coated with carbon, for example with graphitized carbon, which is preferably applied by means of a vacuum deposition process.

[0050] It can further be provided that the generation of the first transport layer comprises a stacking process in which a plurality of sub-layers are stacked to form the first transport layer.

[0051] A guiding structure or transport layer can be formed by a large number of sublayers, for example by stacking differently structured sublayers on top of each other.

[0052] According to a third aspect, the presented invention relates to a cell for a cell stack of an electrolysis system, wherein the cell comprises a possible embodiment of the presented distributor arrangement.

[0053] Advantages that are described in detail for the distributor arrangement for distributing operating media in an electrolysis system according to the first aspect of the invention apply equally to the manufacturing method for producing a distributor arrangement for distributing operating media in an electrolysis system according to the second aspect of the invention and the cell for a cell stack of an electrolysis system according to the third aspect of the invention.

[0054] Due to the presented distribution arrangement, the presented cell can be manufactured with a minimal use of titanium material, making the cell particularly cost-efficient.

[0055] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.

[0056] They show schematically:

[0057] Figure 1 shows a representation of a first possible embodiment of the presented distribution arrangement in a possible embodiment of the presented cell,

[0058] Figure 2 shows a representation of a second possible embodiment of the presented distribution arrangement in a possible embodiment of the presented cell,

[0059] Figure 3 shows a representation of a third possible embodiment of the presented distribution arrangement in a possible embodiment of the presented cell,

[0060] Figure 4 shows a representation of a fourth possible embodiment of the presented distribution arrangement in a possible embodiment of the presented cell, and

[0061] Figure 5 shows a possible design of the presented manufacturing process.

[0062] Identical features are designated by the same reference symbols.

[0063] Figure 1 shows a cell 200 for a cell stack of an electrochemical energy converter. The cell 200 comprises a distributor assembly 100 for distributing operating media within the energy converter, an anode-side catalyst layer 201, a membrane 203, a cathode-side catalyst layer 205, a cathode-side gas diffusion layer 207, and an optional cathode flow distribution structure 209. The distributor assembly 100 comprises a first transport layer 101 connected to a second transport layer 103 and an optional bipolar plate 105.

[0064] The first transport layer is designed here as an example as a structured steel plate coated with a carbon-containing layer 107.

[0065] In the present case, the bipolar plate 105 comprises, for example, a structured surface so that water supply channels 109 are formed between the bipolar plate 105 and the first transport layer 101.

[0066] The bipolar plate 105 is a graphitic plate that is mechanically reinforced by metal elements 111.

[0067] The second transport layer 103 is provided as a porous plate made of titanium or a titanium alloy.

[0068] In Figure 2, the cell 200 comprises a manifold assembly 100 comprising a porous, graphitically structured first transport layer 101 connected to the second transport layer 103 via an optional carbon-containing layer 107.

[0069] Furthermore, the bipolar plate 105 is designed graphitically, and the water supply channels 109 are designed as part of a conductive structure of a structured surface of the first transport layer.

[0070] The first transport layer 101 is provided in the form of a structured carbon / graphite-based foil and directly borders the bipolar plate 105 on the anode side.

[0071] In Figure 2, the first transport layer 101 comprises a channel structure or perforation 113 that runs perpendicular to the second transport layer 103. This perforation consists of randomly shaped holes, for example, round ones, which are configured in particular perpendicular to the body plane or at an angle of <20° to a vertical axis of the first transport layer 101. In Figure 3, the cell 200 comprises a distributor arrangement 100 that comprises a porous first transport layer 101 made of a carbon composite, which is connected to the second transport layer 103 via an optional carbon-containing layer 107.

[0072] The first transport layer 101 is provided in the form of a structured carbon / graphite-based foil and directly borders the bipolar plate 105 on the anode side.

[0073] In Figure 4, the cell 200 comprises a manifold assembly 100 comprising a porous first transport layer 101 made of a carbon material, which is connected to the second transport layer 103 via an optional carbon-containing layer 107.

[0074] The first transport layer 101 is provided in the form of a structured carbon / graphite-based film, for example in the form of an extruded ink applied in particular in different layers, and directly borders the bipolar plate 105 on the anode side.

[0075] Figure 5 shows a manufacturing method 300 for producing a distributor arrangement for distributing operating media in an electrochemical energy converter.

[0076] The manufacturing method 300 comprises a production step 301 in which a first transport layer is produced which is between 100 pm and 2000 pm thick and consists at least partially of a carbon-containing material.

[0077] Furthermore, the manufacturing method 300 comprises an arrangement step 303 in which the first transport layer is arranged on a second transport layer 103 which is between 200 pm and 1000 pm thick and consists at least partially of a titanium-containing material.

[0078] The arrangement step 303 may, for example, comprise a resistance friction welding process.

Claims

Claims 1. A distributor arrangement (100) for distributing operating media in an electrolysis system, the distributor arrangement (100) comprising: a first transport layer (101) consisting at least partially of a carbon-containing material, a second transport layer (103) consisting at least partially of a titanium-containing material, the first transport layer (101) being between 100 pm and 2000 pm thick and the second transport layer (103) being between 200 pm and 1000 pm thick.

2. Distributor arrangement (100) according to claim 1, characterized in that the thickness of the second transport layer (103) is selected such that when using type 1 or type 2 DI water, an electrochemical potential within the second transport layer (103) is below 1.1 V, measured against a standard hydrogen electrode.

3. Distributor assembly (100) according to claim 1 or 2, characterized in that the carbon-containing material contains graphite.

4. Distributor arrangement (100) according to one of the preceding claims, characterized in that the first transport layer (101) has a structured surface on a side facing away from the second transport layer (103), which forms a conductive structure for conducting a medium.

5. Distributor arrangement (100) according to one of the preceding claims, characterized in that the first transport layer (101) has a perforation on a side facing the second transport layer (103).

6. Distributor arrangement (100) according to one of the preceding claims, characterized in that the first transport layer (101) and / or the second transport layer (103) is / are coated at least on one side with a carbon-containing layer (107), in particular a graphite layer.

7. Distributor arrangement (100) according to one of the preceding claims, characterized in that the first transport layer (101) comprises a porous carrier layer made of stainless steel.

8. Distributor arrangement (100) according to one of claims 1 to 6, characterized in that the first transport layer (101) comprises a porous carbon layer made of at least one material from the following list of materials: graphite foam, expanded graphite, carbon particles, hard carbon, carbon black and / or graphite, wherein a binder content of the porous carbon layer is between 5 wt% and 20 wt%.

9. Distributor arrangement (100) according to one of claims 1 to 6, characterized in that the first transport layer (101) comprises a carbon layer made of at least one material from the following list of materials: particles of graphite, fibers of graphite, mixtures of graphite and other carbons, in particular carbon black, hard carbon and / or a polymer matrix filled with carbon particles, the filling degree of which is at least 80%.

10. Distributor arrangement (100) according to one of the preceding claims, characterized in that the distributor arrangement (100) comprises a bipolar plate (105) arranged on the first transport layer (101), wherein the bipolar plate (105) has a structured surface on a side facing the first transport layer (101), which forms a conductive structure (109) for conducting a medium, or the first transport layer (101) has a structured surface on a side facing the bipolar plate (105), which forms a conductive structure (109) for conducting a medium.

11. Manufacturing method (300) for producing a distributor arrangement (100) for distributing operating media in an electrolysis system, the manufacturing method (300) comprising: Creating (301) a first transport layer (101) which is between 100 pm and 2000 pm thick and consists at least partially of a carbon-containing material, and Arranging (303) the first transport layer (101) on a second transport layer (103) which is between 200 pm and 1000 pm thick and consists at least partially of a titanium-containing material.

12. Manufacturing method (300) according to claim 11, characterized in that the production of the first transport layer (101) comprises an extrusion process in which dry extruded layers of a carbon-containing substance are extruded and doped with nitrogen.

13. Manufacturing method (300) according to claim 11 or 12, characterized in that the production of the first transport layer (101) comprises a perforation process in which a number of layers are extruded from a carbon-containing substance and doped with nitrogen.

14. Manufacturing method (300) according to one of claims 11 to 13, characterized in that the production of the first transport layer (101) comprises a forming process in which the first transport layer (101) is formed such that it has a structured surface which forms a conductive structure (109) for conducting a medium, or in that the production of the first transport layer (101) comprises a stacking process in which a plurality of partial layers are stacked to form the first transport layer (101).

15. Cell (200) for a cell stack of an electrolysis system, wherein the cell (200) comprises a distributor arrangement (100) according to one of claims 1 to 10.

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