Electrolysis module and electrolyser
The electrolysis module with a pseudoelastic wire mesh support and insulating separating layer addresses transport and assembly challenges, ensuring stable electrical contact and efficient operation under pressure, enhancing alkaline hydrogen electrolysis performance.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ANDRITZ AG
- Filing Date
- 2025-10-15
- Publication Date
- 2026-05-15
AI Technical Summary
Conventional alkaline electrolyzers face challenges in transport and assembly due to their weight and design complexity, particularly pressurized systems which can weigh up to 90 tons, and issues with irreversible deformation of supporting components under mechanical stress, affecting electrical contact between adjacent cells.
An electrolysis module design featuring a pseudoelastic or superelastic shape-memory alloy wire mesh support structure, combined with an ion-permeable and electrically insulating separating layer, ensures stable electrical contact and mechanical stability under pressure differences, allowing for a compact and efficient electrolysis system.
The design prevents permanent deformations, maintains consistent electrochemical performance, and facilitates easier transport and assembly by reducing weight and complexity, enabling operation at high pressures with improved current density and reduced maintenance needs.
Smart Images
Figure AT2025060382_15052026_PF_FP_ABST
Abstract
Description
[0001] 65161 / AG / VH
[0002] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0003] Electrolysis module and electrolyzer
[0004] The invention relates to an electrolysis module and an electrolyzer for the production of hydrogen.
[0005] Hydrogen production by electrolysis is a known process. In industry, alkaline electrolysis and electrolysis using a proton exchange membrane are particularly common. Most well-known alkaline electrolyzers operate at atmospheric pressure or a slight overpressure of up to 1 bar. These systems are often designed as interconnected individual cells to facilitate transport and assembly. The supply of the medium, often a potassium hydroxide solution (KOH), is separate for each individual cell in the case of an alkaline electrolyzer. The removal of the product and excess KOH is also separate for each individual cell.
[0006] Alkaline electrolyzers can also be designed as pressurized systems. These are typically operated at pressures up to 30 bar. Pressurized electrolyzers are often designed as integrated multi-cell stacks, meaning that the distribution of the alkaline solution and the extraction of the product take place within the individual cells. 65161 / AG / VH
[0007] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0008] The disadvantage of pressurized systems is that they are difficult to transport and assemble. Such systems can weigh up to 90 tons. This design also complicates the mass production of pressurized systems.
[0009] From Austrian patent AT 526232 B1, an electrolysis cell is known in which an anode, a cathode, and a separating layer are provided, as well as two electrically conductive half-shells forming an anode compartment and a cathode compartment. Each half-shell has a circumferential, solid metallic support frame at its edge to absorb compressive forces and encloses a large-area, essentially flat, metallic outer skin. Several electrolysis cells are connected in series so that the outer skins of adjacent cells are in contact with each other. The outer skins are designed as metallic foils with a thickness of less than 0.1 mm. Electrically conductive support structures, preferably comprising metal grids, are arranged in the anode compartment and the cathode compartment to support the outer skins. Such devices are lighter than conventional electrolyzers.
[0010] Similar electrolysis cells for alkaline hydrogen electrolysis feature half-spaces—an anode compartment and a cathode compartment—bounded on one side by metallic bipolar plates and on the other by a separating layer. In the so-called "zero-gap" design, both the separating layer and the metallic bipolar plates are in mechanical and electrical contact via an electrically conductive support component. Since the support component must be permeable to the electrolyte, it is often implemented as a metal grid or nickel foam.
[0011] One problem with these and similar electrolysis cells is that the supporting component of the outer shell or bipolar plate can deform irreversibly under mechanical stress, for example, due to pressure differences between the anode and cathode compartments of cells connected in series. As a result, the outer shells may no longer lie flat against each other, or the supporting components may no longer be in contact with the bipolar plates, thus impairing the electrical contact between adjacent electrolysis cells. 65161 / AG / VH
[0012] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0013] This and other problems of known electrolysis cells are solved by an electrolysis module according to claim 1.
[0014] According to the invention, an electrolysis module for alkaline hydrogen electrolysis is provided, comprising an electrical anode, an electrical cathode and a substantially ion-permeable and electrically insulating separating layer, preferably designed as a membrane or as a diaphragm, which is arranged between the anode and the cathode.
[0015] The electrolysis module has two preferably annular support frames, which are electrically insulated from each other at their edges. The anode is preferably electrically conductively connected to the first support frame, and the cathode is preferably electrically conductively connected to the second support frame. The anode, cathode, and separator layer are arranged between the two support frames, forming an anode compartment and a cathode compartment. The surrounding support frames are designed to withstand compressive forces and can be electrically conductive or insulating.
[0016] A large-area, essentially flat, electrically conductive, and preferably metallic bipolar plate is arranged on at least one support frame. The bipolar plate defines the anode or cathode compartment and makes electrical contact with the anode or cathode. Optionally, a first bipolar plate can make electrical contact with the anode. Optionally, a second bipolar plate can make electrical contact with the cathode. If the support frames are not electrically conductive, electrical contacts can be provided through the support frames to electrically connect the anode or cathode to the respective bipolar plate.
[0017] A support structure for mechanical stabilization is provided in both the anode and cathode compartments. The support structure is preferably metallic and electrically conductive. At least one of the support structures is designed as a wire mesh, wherein the wire mesh comprises or consists of a metallic pseudo- or superelastic shape memory alloy. 65161 / AG / VH
[0018] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0019] A wire mesh according to the invention, made of a pseudo- or superelastic shape-memory alloy, has the advantage that it can withstand high loads without resulting in permanent plastic deformation. The support structure, in the form of a pseudoelastic wire mesh, reduces or prevents deformations of the bipolar plate that can occur due to pressure differences between the anode and cathode compartments. This can delay or eliminate maintenance work. Furthermore, the contact force of the electrodes on the separating layer remains constant even during pressure peaks in the cells, thus ensuring constant electrochemical performance.
[0020] Alkaline hydrogen electrolysis can involve electrolysis using aqueous potassium hydroxide (KOH) or aqueous sodium hydroxide (NaOH) solution as the medium. The medium thus includes the alkalis KOH and NaOH, the gases H₂ and O₂, and mixtures of these substances.
[0021] The electrolysis module is preferably designed as a zero-gap system. The zero-gap system allows direct contact between the electrodes and the interface, resulting in a higher current density (e.g., up to 1000 mA / cm²). 2 This is possible more so than with electrolysis cells where the electrodes are arranged further apart. This design allows for a compact construction and minimizes overvoltages.
[0022] The ion-permeable separating layer is electrically insulating to prevent short circuits between the electrodes. The separating layer is preferably 0.05 mm to 1 mm thick and permeable. It can be configured as a permeable membrane or a diaphragm. Ionic permeability is achieved by the alkali penetrating the separating layer. Gas cannot diffuse through the separating layer due to the polarity of the material, as the separating layer essentially repels nonpolar compounds such as H₂ and O₂. OH⁻ ions, however, can diffuse through the separating layer. Gases can also diffuse through the separating layer in dissolved form, but not in gaseous form, as long as a certain driving pressure gradient is not exceeded. 65161 / AG / VH
[0023] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0024] The separating layer can be, for example, a textile fabric made of plastic fibers with or without an additional hydrophilic coating. Alternatively, a polyphenylene sulfide fabric coated with a mixture of a polymer (e.g., polysulfone) and zirconium oxide (ZrC₆) can also be used as the separating layer.
[0025] The support frames of the electrolysis module are interconnected, preferably by bolting them together. Applying a DC voltage of at least 1.23 volts generates H₂ and OH⁻ in the cathode compartment and O₂ and H₂O in the anode compartment. Since OH⁻ is converted to O₂ and H₂O in the anodic half-reaction, OH⁻ diffuses through the interface into the anode compartment. Typically, during operation, a voltage of 1.48 volts or more exists between the anode and cathode of a single module.
[0026] A wire mesh according to the invention can be formed into a textile-like structure by interlacing wires. It can be made of metal wires, optionally of different metals, or a combination of metal with other materials such as plastics.
[0027] The pseudoelastic or superelastic shape memory alloy according to the invention is a metallic material that allows a large, reversible elastic deformation under load. Optionally, the shape memory alloy comprises or consists of a nickel-titanium alloy with a nickel content of at least 48 wt.%. Preferably, the nickel content is at least 50 wt.%, and particularly preferably at least 55 wt.%, based on the total weight of the nickel-titanium alloy.
[0028] The nickel-titanium alloy can essentially comprise or consist of nickel and titanium. The nickel-titanium alloy may include a known nitinol compound. However, it is also possible that the nickel-titanium alloy includes other metals such as palladium, so that the wire mesh comprises or consists of a nickel-titanium-palladium alloy. 65161 / AG / VH
[0029] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0030] Such alloys are essentially corrosion-resistant under the operating conditions of an electrolysis module or electrolyzer according to the invention.
[0031] Optionally, the shape memory alloy has a martensite deformation temperature above 80°C, preferably above 90°C, so that the shape memory alloy can be used at temperatures from room temperature up to 80°C, preferably up to 90°C.
[0032] Optionally, the shape memory alloy has an austenite finish temperature below approximately 20°C, preferably below approximately 10°C. The austenite finish temperature is the temperature at which the austenite state of a shape memory alloy is essentially fully developed. Pseudoelasticity or superelasticity exists essentially in the temperature range between the austenite finish temperature and the martensite deformation temperature.
[0033] Optionally, it is provided that the shape memory alloy essentially retains its pseudo- or superelastic behavior in a temperature range of approximately 10°C to approximately 90°C, and in particular approximately 20°C to approximately 80°C. In this temperature range, the shape memory alloy according to the invention is essentially pseudoelastic or superelastic.
[0034] If necessary, the wire mesh is designed to essentially fill or even overfill the anode space and / or the cathode space.
[0035] In this embodiment, a first wire mesh can be arranged in the anode compartment such that it contacts the bipolar plate, the anode, and optionally also the support frame. A second wire mesh can also be arranged in the cathode compartment such that it contacts the bipolar plate, the cathode, and the support frame. This embodiment can be advantageous because it reduces or prevents permanent deformations across the entire surface of the electrodes and / or the separating layer. 65161 / AG / VH
[0036] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0037] Overfilling means that the wire mesh, in its relaxed state, protrudes beyond the anode or cathode compartment and is only compressed by the bipolar plate or an adjacent electrolysis module during assembly. This results in the wire mesh being under mechanical stress in the assembled state. For example, the wire mesh might protrude 10%, 20%, or 50% beyond the anode or cathode compartment in its relaxed state.
[0038] It can be provided that both the anode compartment and the cathode compartment have a wire mesh according to the invention. Preferably, however, a conventional support structure is provided in one of the electrode compartments, which is designed as a support plate, in particular trapezoidal sheet, corrugated sheet or truss structure.
[0039] In particular, it can be provided that a conventional support structure is arranged in one electrode compartment, for example in the anode compartment, and a wire mesh according to the invention is arranged in the other electrode compartment, for example in the cathode compartment. The superelastic wire mesh in one electrode compartment can compensate for manufacturing tolerances of the conventional support structure in the other electrode compartment.
[0040] If necessary, the wire mesh can be bonded to the support frame, preferably welded. However, other connection methods are also possible.
[0041] Optionally, the wire mesh can comprise two or more metallic shape memory alloys. According to the invention, the wire mesh can thus be provided with several shape memory alloys whose pseudoelastic properties differ from one another. This can, for example, enable the wire mesh to exhibit very good elastic properties in different temperature ranges, so that the electrolyzer can be used over a wider temperature range.
[0042] The wire mesh can be a single-layer or multi-layer flat knit, a corrugated knit, or a compressed knit. It can also be made of one piece or multiple pieces. 65161 / AG / VH
[0043] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0044] The wire mesh can have a mesh size of 0.2 mm to 20 mm, preferably less than 10 mm. The diameter of the wire in the wire mesh can preferably be 0.1 mm to 0.4 mm. A corrugated knit, for example, can have a height of 0.5 mm to 10 mm. A compressed knit can have a porosity of 50% to 99%. However, other parameters are also possible.
[0045] The support frame and the bipolar plate can be joined by a material bond, preferably by welding. The bipolar plate can be made of alkali-resistant metallic sheet metal with a thickness of approximately 0.8 mm to approximately 1.2 mm, preferably approximately 1.0 mm. The bipolar plate can comprise or consist of alkali-resistant stainless steel, nickel, or a nickel alloy.
[0046] If necessary, the support frame can be designed to be approximately 20 to 200 times thicker than the bipolar plate. The depth of the support frame can range from approximately 1 cm to approximately 20 cm. This creates a stable support frame capable of withstanding the radial pressure forces present inside the electrolysis module.
[0047] Optionally, the support frame may be essentially ring-shaped and the bipolar plate essentially circular. However, the support frame may also be square or rectangular. For better absorption of radial compressive forces, a ring-shaped support frame is preferred, especially for larger dimensions.
[0048] For electrical insulation and sealing of the support frames, a circumferential plastic seal may be provided. Multiple screw connections may preferably be provided to join the support frames.
[0049] For example, the support frames can have a diameter of approximately 1 m to 3 m and a thickness of approximately 1 cm to 3 cm, allowing the electrolysis module to have a thickness of approximately 2 cm to 6 cm. This ensures the stability of the electrolysis module while keeping material costs low and resulting in a relatively low weight of approximately 150 kg to 250 kg for a single electrolysis module with an active area of several m². 2 is reachable. 65161 / AG / VH
[0050] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0051] If necessary, the support frames can each include at least one recess for the supply and discharge of an electrolysis medium.
[0052] Optionally, the electrolysis module is designed to use a potassium hydroxide solution as the electrolysis medium at a temperature in the range of 10°C to 90°C and a pressure above approximately 10 bar, preferably above approximately 30 bar. This embodiment is advantageous because it eliminates the need to compress the product gases H2 and O2 after their production for further use.
[0053] The anode can be nickel or a nickel alloy, with or without a coating. The cathode can also be nickel or a nickel alloy, with or without a coating. The coatings can consist of base metals or minerals, as well as precious metals such as platinum, ruthenium, or indium. The electrodes are porous to allow control over the distribution of the reaction and the transport of substances.
[0054] The invention further relates to an electrolysis block for alkaline ionization
[0055] Hydrogen electrolysis comprising several electrolysis modules according to the invention. The electrolysis modules are arranged in such a way that a closed cathode compartment of a first electrolysis module adjoins a closed anode compartment of a second electrolysis module and are electrically connected to a bipolar plate. The electrolysis modules can be held together by connecting means, in particular screw connections, wherein the connecting means optionally extend through the support frames and press them together. Optionally, the screw connections can be designed to hold together the support frames of several, preferably up to about 400, series-arranged electrolysis modules. The use of such prefabricated electrolysis blocks facilitates the construction and handling of an electrolyzer, since the electrolysis blocks can be transported individually and only need to be assembled on site.
[0056] The invention relates to an electrolyzer for alkaline hydrogen electrolysis, comprising several electrolysis modules arranged in series and preferably horizontally between an electrical positive pole and an electrical negative pole. 65161 / AG / VH
[0057] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0058] The electrolysis modules are arranged in such a way that a closed cathode compartment of a first electrolysis module borders a closed anode compartment of a second electrolysis module and is electrically connected to a bipolar plate.
[0059] Preferably, approximately 100 to 200 electrolysis modules can be arranged in series, and up to 400 electrolysis modules can also be connected in series.
[0060] A DC voltage of approximately 1.5 to 2.5 volts is applied between the electrical positive terminal and the electrical negative terminal per module.
[0061] The electrolyzer can also comprise at least one, or optionally several, electrolysis blocks according to the invention arranged in series between the electrical positive pole and the electrical negative pole, preferably horizontally, with each electrolysis block having a plurality of electrolysis modules according to the invention.
[0062] The electrolysis modules and electrolyzers according to the invention are preferably designed to operate at a pressure of approximately 30 bar and higher, approximately 60 bar. In this case, a pressure of approximately 30 bar or higher prevails in each electrolysis module.
[0063] Preferably, an electrolyzer is provided in which the electrolysis modules and / or the electrolysis blocks are arranged between two end plates, wherein the end plates are preferably clamped by several tie rods, and wherein insulating elements are arranged between the end plates and the poles.
[0064] The invention will now be explained in more detail using non-exclusive exemplary embodiments. These include:
[0065] Figure 1a shows a schematic cross-sectional view of an electrolysis module according to the invention;
[0066] Figure 1b shows a schematic front view of an electrolysis module according to the invention;
[0067] Figure 2 shows a schematic cross-sectional view of an electrolysis block according to the invention;
[0068] Figure 3 shows a schematic cross-sectional view of an electrolyzer according to the invention. 65161 / AG / VH
[0069] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0070] Figure 1a shows a schematic cross-sectional view of an electrolysis module 1 according to the invention for alkaline hydrogen electrolysis. Such an electrolysis module 1 can be manufactured individually and thus in serial production. The materials and components used are essentially resistant to alkalis, oxygen, and hydrogen. Furthermore, the electrolysis module 1, in combination with adjacent electrolysis modules 1, is liquid-tight and gas-tight.
[0071] The electrolysis module 1 comprises an electrical anode 2, where O₂ and H₂O are formed, and an electrical cathode 3, where H₂ and OH⁻ are formed. An electrically insulating barrier 4, in the form of a membrane or diaphragm, is arranged between the two electrodes. This barrier is ion-permeable, allowing OH⁻ ions to diffuse through it and form a closed circuit. The anode 2, the barrier 4, and the cathode 3 are arranged directly adjacent to each other, creating a zero-gap arrangement. The anode 2 and the cathode 3 are not in contact with each other.
[0072] In this embodiment, the separating layer 4 consists of a polyphenylene sulfide fabric containing a mixture of polysulfone and zirconium oxide (ZrÜ2), as well as optionally polytetrafluoroethylene and inorganic additives. It can also be a textile fabric made of plastic fibers with or without an additional (hydrophilic) coating. It is approximately 0.2 mm thick and has a porosity of, for example, 55%. The anode 2 and the cathode 3 are made of nickel.
[0073] The electrolysis module 1 comprises two support frames that are electrically insulated and bolted together at their edges. The support frames 10, 10' are made of nickel or nickel-plated (stainless) steel and at least one flat bipolar plate 11 made of a nickel alloy or nickel-plated (stainless) steel, which are welded together in this embodiment. The support frame 10, 10' is annular and the bipolar plate 11 is circular. The support frame 10, 10' has a thickness of approximately 1.5 cm and a depth of approximately 10 cm. The bipolar plate 11 has a thickness of approximately 1.0 mm. 65161 / AG / VH
[0074] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0075] The support frame 10,10' and the bipolar plate 11 have a diameter of approximately 2 m. With these dimensions, the electrolysis module 1 weighs approximately 150 kg to approximately 250 kg.
[0076] The anode 2 can be electrically connected to the support frame 10, while the cathode 3 can be electrically connected to the second support frame 10'. The anode 2, together with the first support frame 10, is separated from the cathode 3, together with the second support frame 10', by the separating layer 4, thus forming an anode compartment 6 and a cathode compartment 7. An electrically insulating plastic seal can also be arranged between the two support frames 10, 10'.
[0077] The support frame 10, 10' has recesses 5 suitable for the supply lines 8, 8' and outlets 9, 9' for a medium, wherein the supplied medium in this embodiment is a KOH solution with a concentration between approximately 10 wt.% and approximately 40 wt.%. The medium discharged from the anode compartment 6 is a mixture of O₂ and KOH solution. The medium discharged from the cathode compartment 7 is a mixture of H₂ and KOH solution.
[0078] In this embodiment, a support structure 12 is arranged in the anode compartment 6 and a support structure 12' in the cathode compartment 7, wherein the support structure 12' in the cathode compartment 7 is designed as a wire mesh and the support structure 12 is a support plate in the form of a trapezoidal sheet. The wire mesh substantially fills the cathode compartment 7, so that it contacts the bipolar plate 11 and the respective support frames 10, 10' as well as the cathode 3. The wire mesh can even overfill the cathode compartment 7, so that in an assembled electrolyzer it is compressed and substantially fills the electrode compartment. The wire mesh is welded to the support frames 10, 10'.
[0079] The wire mesh is formed from wires comprising or consisting of a nickel-titanium alloy. The nickel-titanium alloy contains approximately 55 wt.% nickel based on the total weight of the alloy. This nickel-titanium alloy is a pseudoelastic shape-memory alloy. The wires have a diameter of approximately 0.3 mm. The wire mesh is substantially corrosion-resistant under the operating conditions of electrolysis module 1 or the electrolyzer. 65161 / AG / VH
[0080] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0081] The support plate is essentially corrosion-resistant and consists of or comprises nickel-plated (stainless) steel.
[0082] The nickel-titanium alloy is designed to behave pseudoelastically or superelastically under the operating conditions of electrolysis module 1 or the electrolyzer. This reduces or prevents stresses and deformations of the bipolar plate of electrolysis module 1.
[0083] Figure 1b shows a front view of an electrolysis module 1 according to the invention. The front view shows the recesses 5, which contain the supply lines 8, 8' and discharge lines 9, 9', through which the electrolysis medium is supplied and discharged, and the product is discharged. The recesses 5 can essentially be provided as bores through the support frame, with the recesses 5 forming a tube-like connection in the case of electrolysis modules 1 connected in series.
[0084] The support frame 10, which forms the anode chamber 6, has a recess 5 for the supply line 8 and a recess 5 for the discharge 9, wherein the recess 5 of the supply line 8 and the discharge 9 each have a bore which forms a connection between the anode chamber 6 and the recess 5.
[0085] The support frame 10', which forms the cathode chamber 7, has a recess 5 for the inlet 8' and a recess 5 for the outlet 9', wherein the recess 5 of the inlet 8' and the outlet 9' each have a bore which forms a connection between the cathode chamber 7 and the recess 5.
[0086] Figure 2 shows a schematic cross-sectional view of an electrolysis block 13 according to the invention for alkaline hydrogen electrolysis. The electrolysis block 13 comprises several electrolysis modules 1 as shown in Figure 1. The electrolysis modules 1 are arranged in such a way that a closed cathode compartment 7 and a closed anode compartment 6 are each formed. The anode compartment 6 and the cathode compartment 7 are bounded on their outer sides by a bipolar plate 11, so that the individual electrolysis modules 1 are separated from each other by a single bipolar plate 11 and electrically connected to each other. 65161 / AG / VH
[0087] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0088] The electrolysis modules 1 are held together by fasteners, in particular screw connections (not shown). In the present example, two screw connections are provided, but more than two fasteners can also be provided. The fasteners extend completely through the support frames 10, 10' and press them firmly together, resulting in good electrical contact between the electrolysis modules 1.
[0089] In an embodiment not shown, electrically conductive adapter plates with recesses are provided on the two end faces of the electrolysis block 13 to receive the end pieces of the connecting elements, namely the screw nuts, flush. This allows several electrolysis blocks 13 to be arranged in series with good electrical contact.
[0090] Figure 3 shows a schematic cross-sectional view of an electrolyzer according to the invention. The electrolyzer comprises approximately 200 electrolysis modules 1 arranged in series between an electrical positive pole 14 and an electrical negative pole 15, according to the embodiment shown in Figure 1. The electrolysis modules 1 are arranged in such a way that a closed cathode compartment 7 and a closed anode compartment 6 are each formed. The anode compartment 6 and the cathode compartment 7 are bounded on their outer sides by a bipolar plate 11, so that the individual electrolysis modules 1 are separated from each other by a single bipolar plate 11 and are electrically connected to each other.
[0091] In this embodiment, the wire mesh in the cathode compartments 7 is compressed in the assembled electrolyzer so that it essentially fills the entire cathode compartment. It is also possible for the cathode compartment 7 and the anode compartment 6 to each be filled by a wire mesh.
[0092] The electrolysis modules 1, arranged in series, are clamped between two end plates 17, with insulating elements 16 arranged between the end plates 17 and the positive terminal 14 and the negative terminal 15. 65161 / AG / VH
[0093] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0094] In this embodiment, the end plates 17 are connected to each other by tie rods (not shown) and are firmly clamped together.
[0095] Alternatively, an electrolyzer can be configured with electrolysis blocks 13 arranged in series and horizontally between an electrical positive pole 14 and an electrical negative pole 15. The outer surfaces of adjacent electrolysis blocks 13 are flush and electrically conductive, ensuring good and full-surface electrical contact.
[0096] The electrolysis blocks 13 can be arranged between two solid end plates 17, the end plates 17 being rigidly clamped by several (not shown) tie rods. Insulating elements 16 are arranged between the end plates 17 and the poles 14, 15.
[0097] During operation of the electrolyzer, KOH solution is introduced into the electrolysis modules 1 via the supply lines 8, 8'. The pressure of up to 30 bar and more within the electrolysis modules 1 is generated by the controlled retention of the product gases or by hydraulic compression. The support frame 10, 10' is designed to absorb the resulting radial pressure forces. The end plates 17, which are clamped with tie rods, absorb axial pressure forces acting on the electrolysis modules 1, so that a high pressure can be applied despite the thin bipolar plates 11 of the individual electrolysis modules 1.
[0098] Subsequently, a DC voltage of 1.5 to 2.5 volts per cell is applied between the positive terminal 14 and the negative terminal 15, thereby initiating electrolysis. During this process, O₂ and H₂O are formed at the anode 2, and H₂ and OH⁻ at the cathode 3. OH⁻ ions can diffuse between the two electrodes through the separating layer 4 from the cathode compartment 7 into the anode compartment 6. The product gases H₂ and O₂ can be introduced from the individual electrolysis modules 1 into pressure collection lines via leads 9, 9', which are provided in the upper area of the support frames 10, 10', and fed to separators for the separation of the lye and H₂ or O₂. 65161 / AG / VH
[0099] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0100] However, the invention is not limited to the described embodiments, but includes all devices and methods within the scope of the following patent claims.
[0101] 65161 / AG / VH
[0102] Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)
[0103] Reference symbol list
[0104] 1 electrolysis module
[0105] 2 Anode
[0106] 3 Cathode
[0107] 4 Separation layer
[0108] 5 Exclusion
[0109] 6 anode compartment
[0110] 7 Cathode space
[0111] 8.8" supply line
[0112] 9, 9" derivative
[0113] 10.10" support frame
[0114] 11 Bipolar plate
[0115] 12, 12" support structure
[0116] 13 Electrolysis block
[0117] 14 positive poles
[0118] 15 Negative pole
[0119] 16 insulating element
[0120] 17 end plates
Claims
65161 / AG / VH Andritz AG, Stattegger Strasse 18, 8045 Graz (AT) Patent claims 1. Electrolysis module (1) for alkaline hydrogen electrolysis, comprising: - an electrical anode (2), an electrical cathode (3) and a substantially ion-permeable and electrically insulating separating layer (4) arranged between the anode (2) and the cathode (3), - two preferably ring-shaped support frames (10,10') which are electrically insulated from each other at their edges, - wherein the anode (2) is preferably electrically connected to the first support frame (10), and the cathode (3) is preferably electrically connected to the second support frame (10'), and - wherein the anode (2), the cathode (3) and the separating layer (4) are arranged between the two support frames (10, 10') so that an anode space (6) and a cathode space (7) are formed, and - wherein a large-area, essentially planar, electrically conductive bipolar plate (11) is arranged on at least one support frame (10, 10'), characterized in that - a support structure (12, 12') is provided in the anode space (6) and in the cathode space (7), wherein - at least one of the support structures (12') is designed as a wire mesh comprising or consisting of a metallic pseudoelastic shape memory alloy.
2. Electrolysis module (1) according to claim 1, characterized in that the shape memory alloy comprises or consists of a nickel-titanium alloy with a nickel content of at least 48 wt.%, preferably at least 50 wt.%, particularly preferably at least 55 wt.%, based on the total weight of the nickel-titanium alloy.
3. Electrolysis module (1 ) according to claim 1 or 2, characterized in that the shape memory alloy has a martensite deformation temperature of over 80°C, preferably over 90°C. 65161 / AG / VH Andritz AG, Stattegger Strasse 18, 8045 Graz (AT) 4. Electrolysis module (1 ) according to one of claims 1 to 3, characterized in that the shape memory alloy has an austenite finish temperature which is below about 20°C, preferably below about 10°C.
5. Electrolysis module (1 ) according to one of claims 1 to 4, characterized in that the shape memory alloy essentially retains its pseudoelastic behavior in a temperature range of about 20°C to about 80°C, preferably about 10°C to about 90°C.
6. Electrolysis module (1 ) according to one of claims 1 to 5, characterized in that the wire mesh substantially completely fills and optionally overfills the anode space (6) and / or the cathode space (7), wherein the wire mesh is arranged in the anode space (6) and / or the cathode space (7) such that it contacts the bipolar plate (11), the anode (2) and / or the cathode (3) and optionally also the respective support frame (10, 10').
7. Electrolysis module (1 ) according to one of claims 1 to 6, characterized in that at least one support structure (12) is designed as a support plate, in particular as a trapezoidal sheet or corrugated sheet, or as a truss structure.
8. Electrolysis module (1 ) according to one of claims 1 to 7, characterized in that the wire mesh comprises two or more metallic shape memory alloys which differ in their pseudoelastic properties.
9. Electrolysis module (1 ) according to one of claims 1 to 8, characterized in that the wire knitting is a single-layer or multi-layer flat knitting, a corrugated knitting or a compressed knitting.
10. Electrolysis module (1 ) according to one of claims 1 to 9, characterized in that the support frames (10, 10') each have several recesses (5) for supply lines (8, 8') and for discharge lines (9, 9') of an electrolysis medium. 65161 / AG / VH Andritz AG, Stattegger Strasse 18, 8045 Graz (AT) 11. Electrolysis module (1 ) according to one of claims 1 to 10, characterized in that it is designed to use as an electrolysis medium a potassium hydroxide solution with a temperature in the range of about 20°C to about 80°C, preferably about 10°C to about 90°C, at a pressure of about 10 bar, preferably about 30 bar.
12. Electrolysis block (13) for alkaline hydrogen electrolysis, comprising several electrolysis modules (1 ) according to one of claims 1 to 11, wherein the electrolysis modules (1 ) are arranged in such a way that a closed cathode compartment (7) of a first electrolysis module (1 ) borders a closed anode compartment (6) of a second electrolysis module (1 ) and is electrically connected to a bipolar plate (11 ).
13. Electrolyzer for alkaline hydrogen electrolysis, comprising several electrolysis modules (1 ) arranged serially and preferably horizontally between an electrical positive pole (14) and an electrical negative pole (15) according to one of claims 1 to 12, wherein the electrolysis modules (1 ) are arranged in such a way that a closed cathode compartment (7) of a first electrolysis module (1 ) borders a closed anode compartment (6) of a second electrolysis module (1 ) and is electrically connected to a bipolar plate (11 ).
14. Electrolyzer for alkaline hydrogen electrolysis, comprising at least one, optionally several, electrolysis blocks (13) arranged in series between an electrical positive pole (14) and an electrical negative pole (15), preferably horizontally, according to claim 12.
15. Electrolyzer according to one of claims 13 or 14, characterized in that the electrolysis modules (1 ) and / or the electrolysis blocks (13) are arranged between two end plates (17), wherein the end plates (17) are preferably clamped firmly by several tie rods, and wherein insulating elements (16) are arranged between the end plates (17) and the poles (14, 15).