Compensation element for an electrolysis cell of an electrolysis device, electrolysis cell, and electrolysis device

Abstract

The invention relates to a compensation element (20) for an electrolysis cell of an electrolysis device consisting of multiple stack elements, wherein the compensation element (20) is used to provide a defined contact pressure and pressure compensation between the stack elements of the electrolysis cell, comprising at least one first metal sheet (21) and at least two second metal sheets (22, 23), between which a respective first metal sheet (21) is sandwiched, wherein the second metal sheets (22, 23) have protrusions (24, 25) which rest against the respective first metal sheet (21) and exert a bending load on the respective first metal sheet (21) when force is applied to the second metal sheets (22, 23).

Description

[0001] 1 / 18 EM 12506

[0002] Quest One GmbH

[0003] Compensating element for an electrolysis cell of an electrolysis device, electrolysis cell and electrolysis device

[0004] The invention relates to a balancing element for an electrolysis cell of an electrolysis device. Furthermore, the invention relates to an electrolysis cell of an electrolysis device and an electrolysis device.

[0005] DE 102017 108413 A1 discloses an electrolysis device with a cell stack consisting of several cell stack elements. Furthermore, the electrolysis device known from this prior art has a force application unit by which a force can be exerted on the cell stack to compress the cell stack elements of the cell stack in a fluid-tight manner. The compressed cell stack elements form electrolysis cells.

[0006] Although the force-application unit of an electrolysis device allows the cell stack elements and thus the electrolysis cells to be pressed together in a defined manner, there is a need to provide a compensating element in an electrolysis cell in order to provide a defined contact pressure between the cell stack elements of the cell stack and thus between the stack elements of the electrolysis cell, in particular to compensate for dimensional changes caused by pressure fluctuations during operation and thus to ensure the most consistent possible contact of the stack elements or cell stack elements under all operating conditions.

[0007] EP 2957659 B1 discloses a fluid conduction structure of an electrolysis cell designed as a gas diffusion layer, wherein an outer layer of the gas diffusion layer is designed as a spring component with a progressive spring characteristic.

[0008] 08.01.20262 / 18 EM 12506

[0009] EP 2985096 B1 discloses an electrolysis cell with a catalyst-coated membrane arranged between electrodes, wherein a gas diffusion electrode consists of a plurality of expanded metal layers arranged in layers.

[0010] There is a need for a simple and cost-effective compensating element for an electrolysis cell of an electrolysis device with optimal spring properties, small installation space requirement and the longest possible service life.

[0011] Starting from this, the present invention is based on the objective of creating a novel compensating element for an electrolysis cell of an electrolysis device, an electrolysis cell of an electrolysis device with such a compensating element and an electrolysis device with such an electrolysis cell.

[0012] This problem is solved by a compensating element according to claim 1, by an electrolysis cell according to claim 13 and by an electrolysis device according to claim 17.

[0013] The compensating element according to the invention for an electrolysis cell of an electrolysis device consisting of several stacked elements serves to provide a defined contact pressure and pressure equalization between the stacked elements of the electrolysis cell. The compensating element according to the invention comprises at least one first metal sheet and at least two second metal sheets. A first metal sheet is arranged sandwich-like between each pair of second metal sheets, wherein the second metal sheets have projections that bear against the respective first metal sheet and, when force is applied to the second metal sheets, exert a bending load on the respective first metal sheet.

[0014] 08.01.20263 / 18 EM 12506

[0015] Such a compensating element possesses optimal spring properties, which in particular enable the compensation of pressure fluctuations occurring during the operation of an electrolysis cell, thus ensuring uniform force transmission. It requires little installation space and can be manufactured cost-effectively. Furthermore, such a compensating element serves to compensate for tolerances with respect to the other components in the electrolysis cell.

[0016] The invention advantageously enables adaptation to the specific configuration of an electrolysis cell or a stack of electrolysis cells, for example, by suitable variation of the materials used for the metal sheets and / or projections, the sheet thicknesses, and / or the design and arrangement of the projections. In this way, a compensating element designed according to the invention can be modified relatively easily without having to change the general design principle, for example, to adapt it to changing contact pressures in an electrolysis cell.

[0017] Furthermore, it is alternatively or additionally possible to adjust the spring properties of the compensating element in a targeted and required manner by varying the number of first and second metal sheets.

[0018] Preferably, the first metal sheet is elastically deformable under the operating conditions of an electrolysis cell and is made of a material with a higher yield strength than the material of the second metal sheets. In particular, the first metal sheet is made of titanium grade 2, titanium grade 3, titanium grade 4, or titanium grade 5. This is preferred to achieve optimal dimensional stability and ensure that no or only minimal plastic deformation occurs under the operating conditions of an electrolysis cell, while simultaneously guaranteeing favorable manufacturability and a small installation space requirement.

[0019] 08.01.20264 / 18 EM 12506

[0020] Preferably, the second metal sheets, or at least their projections, are made of a material with a lower yield strength than the material of the respective first metal sheet. Preferably, the second metal sheets, or at least their projections, are made of Grade 1 titanium. The projections of the second metal sheets, and thus the second metal sheets with the projections, are preferably not deformable or only minimally deformable under the operating conditions of an electrolysis cell. Particularly preferably, the second metal sheets with the projections are shaped, i.e., have a geometry, such that they exhibit higher stiffness than the respective first metal sheet. According to a particularly preferred embodiment, the projections of the second metal sheets are formed, in particular, by deep drawing, whereby a particularly high dimensional stability can be achieved due to the cold forming process and the resulting geometry.This is also preferred in order to ensure the optimal spring properties of the compensating element while ensuring easy manufacturing and low installation space requirements for the compensating element.

[0021] Under operating conditions of an electrolysis cell, the pressure on the hydrogen side of the cell is typically between 35 and 40 bar, while the pressure on the oxygen side is typically close to ambient pressure. During start-up and shutdown, the pressure on the hydrogen side of the electrolysis cell can fluctuate significantly.

[0022] Preferably, the projections of the second metal sheets are offset from one another such that between two immediately adjacent projections of a first of the second metal sheets, which abut a first side of the respective first metal sheet, a projection of a second of the second metal sheets abuts a second side of the respective first metal sheet, wherein the respective first metal sheet is arranged sandwich-like between these two second metal sheets, whose projections abut opposite sides of the respective first metal sheet. This ensures optimal spring properties of the compensating element. A particularly suitable embodiment provides in this

[0023] 08.01.20265 / 18 EM 12506

[0024] The arrangement is such that one projection of the second of the two metal sheets is positioned centrally with respect to two adjacent projections of the first of the two metal sheets located on the opposite side of the first metal sheet. Viewed perpendicular to the metal sheets, the projections of each of the two second metal sheets are preferably located centrally between the projections of the other second metal sheet.

[0025] Preferred embodiments of the invention are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows:

[0026] Fig. 1 shows an exploded view of a first compensating element according to the invention for an electrolysis cell consisting of several stacked elements of an electrolysis device,

[0027] Fig. 2 shows an assembly of the compensating element of Fig. 1, Fig. 3 shows a top view of one of the first of the second or outer metal sheets of the compensating element of Fig. 1,

[0028] Fig. 4 shows a top view of the first or inner metal sheet of the compensating element of Fig. 1.

[0029] Fig. 5 shows a top view of a second of the second or outer metal plates of the compensating element of Fig. 1 ,

[0030] Fig. 6 shows an exploded view of a half-cell of an electrolysis cell having the compensating element of Fig. 1,

[0031] Fig. 7 shows an exploded view of a half-cell of an electrolysis cell comprising a second compensating element according to the invention, Fig. 8 shows an exploded view of a third compensating element according to the invention for an electrolysis cell of an electrolysis device consisting of several stacked elements,

[0032] 08.01.20266 / 18 EM 12506

[0033] Fig. 9 shows an exploded view of a fourth compensating element according to the invention for an electrolysis cell consisting of several stacked elements of an electrolysis device,

[0034] Fig. 10 shows an exploded view of a fifth compensating element according to the invention for an electrolysis cell consisting of several stacked elements of an electrolysis device,

[0035] Fig. 11 shows an exploded view of a sixth compensating element according to the invention for an electrolysis cell consisting of several stacked elements of an electrolysis device.

[0036] The invention relates to a compensating element 20 for an electrolysis cell of an electrolysis device consisting of several stacked elements. Fig. 1 shows an exploded view of a first compensating element 20 according to the invention, Fig. 2 shows an assembly view of this compensating element 20, wherein in Fig.

[0037] Figures 1 and 2 show that the compensating element 20 comprises a first, middle metal sheet 21 and two second, outer metal sheets 22, 23. In the compensating element 20 of Figures 1 and 2, the first, middle metal sheet 21 is sandwiched between the two second, outer metal sheets 22, 23, with the two second, outer metal sheets 22, 23 having projections 24, 25 that bear against the first, middle metal sheet 21 and, when a force is applied to at least one of the second, outer metal sheets 22, 23, exert a bending load on the first, middle metal sheet 21. The projections 24 of the second, outer metal sheet 22 and the projections 25 of the second, outer metal sheet 23 bear against opposite sides of the first, middle metal sheet 21, i.e., they face the first, middle metal sheet 21. Figs. 3, 4 and 5 each show a top view of the metal sheets 21, 22 and 23.

[0038] The first, middle metal sheet 21 of the compensating element 20 is elastically deformable under the operating conditions of an electrolysis cell incorporating the compensating element 20. It is made of a material with a higher yield strength than the material of the two second, outer metal sheets 22, 23.

[0039] 08.01.20267 / 18 EM 12506

[0040] The first, middle metal sheet 21 preferably consists of titanium grade 2, titanium grade 3, titanium grade 4 and titanium grade 5.

[0041] The projections 24, 25 of the two second, outer metal sheets 22, 23, and thus the two second, outer metal sheets 22, 23 with the projections 24, 25, are not deformable or only minimally deformable under operating conditions of the electrolysis cell having the compensating element 20, neither elastically nor plastically. The two second, outer metal sheets 22, 23 are preferably made of titanium grade 1.

[0042] Under operating conditions of an electrolysis cell, the pressure on the hydrogen side of the cell is typically between 35 and 40 bar, while the pressure on the oxygen side is typically close to ambient pressure. During start-up and shutdown, the pressure on the hydrogen side of the electrolysis cell can fluctuate significantly.

[0043] The two second, outer metal sheets 22, 23 have a higher stiffness than the first, inner metal sheet 21.

[0044] The projections 24, 25 of the second, outer metal sheets 22, 23 are preferably formed by cold forming of the respective outer metal sheet 22, 23, whereby high strength projections are provided by cold forming.

[0045] The first, inner metal sheet 21 is, in particular, a thin metal plate that is not deformed three-dimensionally but merely has a planar extent. The second, outer metal sheets 22, 23 with the projections 24, 25 are three-dimensionally formed via the projections 24, 25. The first, inner metal sheet 21 and the second, outer metal sheets 22, 23 can have the same thickness or different thicknesses. Then, if

[0046] 08.01.20268 / 18 EM 12506

[0047] Since the same metal sheets have different thicknesses, the thickness of the second, outer metal sheet 22 is greater than the thickness of the first, inner metal sheet 21. For example, the first, middle metal sheet 21 might have a thickness of 0.25 mm, and the second, outer metal sheets 22 and 23 might have a thickness of 0.3 mm. These thicknesses are purely illustrative.

[0048] The projections 24, 25 of the second, outer metal sheets 22, 23 are offset from one another such that between two immediately adjacent projections 24 of a first metal sheet 22 of the two second, outer metal sheets 22, 23, which abut a first side of the inner, first metal sheet 21, a projection 25 of a second metal sheet 23 of the second, outer metal sheets 22, 23 abuts a second side of the first, inner metal sheet. In Fig. 3, the position of the projections 25 of the metal sheet 23, relative to the position of the projections 24 of the metal sheet 22, is shown in dotted lines. Fig. 5 shows in dotted lines the position of the projections 24 of the metal sheet 22 relative to the projections 25 of the metal sheet 23.

[0049] According to Figs. 3 and 5, the projections 24, 25 of the respective second, outer metal sheet 22, 23 are arranged in an array-like manner in columns and rows, wherein the rows and columns of the second metal sheets 22, 23 are offset from each other.

[0050] In the illustrated embodiment, the projections 24 of the outer metal sheet 22 are arranged equidistantly to each other, as are the projections 25 of the second, outer metal sheet 23, which are arranged equidistantly to each other, with all projections 24, 25 being identical.

[0051] Preferably, a projection 25 of a second of the second metal sheets 23 is arranged centrally with respect to two adjacent projections 24 of the first of the second metal sheets 22, which are arranged on the other side of the first metal sheet. In the viewing direction perpendicular to the metal sheets 22, 23, the

[0052] 08.01.20269 / 18 EM 12506

[0053] Projections 24, 25 each of the two second metal sheets 22, 23 preferably centrally between the projections d25, 24 of the other second metal sheet 23, 22.

[0054] In the embodiment shown in Figures 1 to 5, the outer second metal sheet 22 further has fluid guide openings 26, which serve to allow the flow of a fluid. When the compensating element 20 is installed on the cathode side of a hydrogen side of the electrolysis cell, these fluid guide openings 26 serve to allow the flow of hydrogen. Conversely, when the compensating element 20 is arranged on the anode side of a water side of the respective electrolysis cell, the fluid guide openings 26 serve to allow the flow of water and oxygen.

[0055] Fig. 6 shows an exploded view of a half-cell 27 of an electrolysis cell, wherein, according to Fig. 6, the compensating element 20 shown therein is arranged between a catalyst-coated membrane 28 and a bipolar plate 29, which serves as the cathode of the respective electrolysis cell. A fluid guide structure 30 is also arranged between the compensating element 20 and the catalyst-coated membrane 28, which, according to Fig. 6, serves to remove the hydrogen produced during electrolysis. This hydrogen flows, according to arrows 31, through the fluid guide openings 26 of the outer metal sheet 22 of the compensating element 20 facing the catalyst-coated membrane 28, into a cavity bounded by the outer metal sheet 22 and the inner metal sheet 21 of the compensating element 20, in order to be removed from the electrolysis cell in the direction of arrows 32.

[0056] In contrast, Fig. 7 shows an exploded view of a half-cell 27 of an electrolysis cell, in which fluid guide openings 26 are provided in all metal sheets 21, 22 and 23 of the compensating element 20. Therefore, in Fig. 7, the hydrogen produced during electrolysis flows completely through the compensating element 20 towards the bipolar plate 29, in order to be discharged, in the direction of arrows 32, through a cavity formed between the bipolar plate 29 and the metal sheet 23 facing the bipolar plate 29.

[0057] 08.01.202610 / 18 EM 12506

[0058] The individual metal sheets 21, 22, 23 can be bonded together, for example by contact welding. This increases the electrical conductivity and reduces the electrical resistance between the individual metal sheets 21, 22, and 23. Alternatively, the individual metal sheets 21, 22, 23 may not be bonded together. In this case, the individual metal sheets 21, 22, 23 can slide relative to each other perpendicular to their stacking direction, thereby homogenizing the force distribution.

[0059] In Figures 1 to 7, the projections 24, 25 of the outer metal sheets 22, 23 shown therein are each designed as convex bumps or bulges. The projections 23, 24 are identical in their shape and / or dimensions and are uniformly distributed over the respective metal sheet 22, 23. In contrast, it is also possible that in individual sections of the metal sheets 22, 23, particularly in central areas, a higher density of projections 23, 24 is formed than in other areas, particularly in outer edge regions, of the respective metal sheet 22, 23. This serves, in particular, to adapt a spring characteristic curve of the compensating element 20.Furthermore, if the shape and / or dimensions of the projections 23, 24 of the metal sheets 22, 23 differ from one another, the spring behavior of the compensating element 20 can be advantageously adjusted to provide either a linear, progressive or degressive spring behavior for the respective compensating element 20.

[0060] Fig. 8 shows an exploded view of an alternative compensating element 20, in which the projections 24, 25 on the outer metal sheets 22, 23 are not formed by convex bumps or bulges, but as additional cylindrical elements that are welded to the metal sheet 22, 23.

[0061] Fig. 9 also shows an exploded view of another compensating element 20, in which, as in Fig. 8, the projections 24, 25 are attached to the respective surface by welding. 08.01.202611 / 18 EM 12506

[0062] The metal sheets 22, 23 are formed on the metal sheets, but the dimensions of the projections 24, 25 differ from one another. Thus, according to Fig. 9, projections 24, 25 of different heights are provided on each metal sheet 22, 23.

[0063] Fig. 10 shows a section of a compensating element 20 in which the projections 24, 25 are contoured in a triangular shape, tapering to a point on the first, middle metal sheet 21.

[0064] In Figs. 1 to 8, the projections 24, 25 of the second metal sheets 22, 23 have plateau-like contact surfaces with which the second metal sheets 22, 23 lie flat against a respective first metal sheet 21.

[0065] In Figures 10 and 11, the projections 24, 25, 45, 46, 47 of the second metal sheets 22, 23, 42, 33, 44 are tapered and lie in line against a respective first metal sheet 21. However, the plateau-like contact surfaces of Figures 1 to 8 are preferred in order to ensure their dimensional stability even under load.

[0066] In the embodiments shown in Figures 1 to 10, the compensating elements 20 have a total of three metal sheets: a first, middle metal sheet 21 and two second, outer metal sheets 22, 23. In contrast, Figure 11 shows a compensating element 40 with a total of five metal sheets: two first metal sheets 41 and three second metal sheets 42, 43, 44. The first metal sheets 41 are designed like the first metal sheet 21 in Figures 1 to 10 and are arranged in a sandwich-like manner between two second metal sheets 42 and 44 or 43 and 44, respectively. The second metal sheets 42, 43, 44, like the second metal sheets 22, 23 of Figs. 1 to 10, have projections 45, 46, 47. The projections 45, 47 and the projections 47, 46 of the second metal sheets 42, 43, 44 abutting the same first metal sheet 41 are again offset from each other.The metal sheets 42, 43 have the projections only on one side, while the metal sheet 44 has the projections 47 on two sides.

[0067] 08.01.202612 / 18 EM 12506

[0068] Although no fluid guide openings 26 are shown in Figs. 8 to 11, the metal sheets can of course have such fluid guide openings.

[0069] The invention further relates to an electrolysis cell of an electrolysis device with at least one compensating element 20, 40 according to the invention, wherein an electrolysis cell has a catalyst-coated membrane 28 arranged between two bipolar plates and fluid conduction structures 30 arranged between the catalyst-coated membrane 28 and the bipolar plates 29, which serve on the cathode side for the transport of hydrogen and on the anode side for the transport of water and oxygen.

[0070] Preferably, a compensating element 20, 40 according to the invention is arranged only at one position of an electrolysis cell, either on the cathode side or the anode side, i.e. either on the hydrogen side or water side of the respective electrolysis cell, namely between the respective bipolar plate 29 and the respective fluid conducting structure 30.

[0071] When the respective balancing element 20, 40 is installed on the cathode side, it exhibits a higher preload in the inactive electrolysis cell than at the operating point when the electrolysis cell is active. Conversely, when the respective balancing element 20, 40 is installed on the anode side, it exhibits a lower preload in the inactive electrolysis cell than at the respective operating point when the electrolysis cell is active. Therefore, a balancing element 20, 40 installed on the cathode side experiences a relaxation of the preload in the direction of the active operating point, while a balancing element 20, 40 installed on the anode side experiences a tensioning of the preload in the direction of the active operating point.

[0072] 08.01.202613 / 18 EM 12506

[0073] The compensating elements 20, 40 can also be referred to as spring elements 20, 40. The thickness of the compensating elements 20, 40 can be between 0.5 mm and 5 mm, preferably between 1 mm and 2.5 mm. The compensating elements 20, 40 can provide a contact pressure between 1 MPa and 5 MPa, preferably between 2 MPa and 4 MPa, and particularly preferably between 2.5 MPa and 3.5 MPa.

[0074] The invention allows stacking elements of an electrolysis cell, and thus cell stacking elements of a cell stack of an electrolysis device comprising multiple electrolysis cells, to be pressed together with a defined force and a defined contact pressure between the stacking elements throughout the entire operating range. This is important for the tightness of the electrolysis cells in order to prevent leaks in the electrolysis cells across the entire operating range.

[0075] January 8, 2026

Claims

14 / 18 EM 12506 Claims 1. Compensating element (20; 40) for an electrolysis cell of an electrolysis device consisting of several stacking elements, wherein the compensating element (20; 40) serves to provide a defined contact pressure and pressure equalization between the stacking elements of the electrolysis cell, comprising at least one first metal sheet (21; 41) and at least two second metal sheets (22, 23; 42, 43, 44), between which a respective first metal sheet (21; 41) is arranged in a sandwich-like manner, wherein the second metal sheets (22, 23; 42, 43, 44) have projections (24, 25; 45, 46, 47) which bear against the respective first metal sheet (21; 41) and, when a force is applied to the second metal sheets (22, 23; 42, 43, 44), exert a bending load on the respective first metal sheet (21; 41). exercise.

2. Compensating element (20; 40) according to claim 1 , characterized in that the respective first metal sheet (21; 41) is elastically deformable under operating conditions of an electrolysis cell.

3. Compensating element (20; 40) according to claim 1 or 2, characterized in that the respective first metal sheet (21; 41) consists of a material which has a higher yield strength than the material of the second metal sheets (22, 23; 42, 43, 44).

4. Compensating element (20; 40) according to claim 3, characterized in that the respective first metal sheet (21; 41) is made of titanium grade 2, titanium grade 3, titanium grade 4 or titanium grade 5. 08.01.202615 / 18 EM 12506 5. Compensating element (20; 40) according to claim 1, 2, 3 or 4, characterized in that at least the projections (24, 25; 45, 46, 47) of the second metal sheets (22, 23; 42, 43, 44) are not deformable or only minimally deformable under operating conditions of an electrolysis cell.

6. Compensating element (20; 40) according to one of claims 1 to 5, characterized in that the second metal sheets (22, 23; 42, 43, 44) are made of titanium grade 1.

7. Compensating element (20; 40) according to one of claims 1 to 6, characterized in that the projections (24, 25; 45, 46, 47) of the second metal sheets (22, 23; 42, 43, 44) are formed by cold forming.

8. Compensating element (20; 40) according to one of claims 1 to 7, characterized in that the projections (24, 25; 45, 46, 47) of the second metal sheets (22, 23; 42, 43, 44) are offset from one another in such a way that between two immediately adjacent projections of a first of the second metal sheets, which abut a first side of the respective first metal sheet (21; 41), a projection of a second of the second metal sheets abuts a second side of the respective first metal sheet (21; 41).

9. Compensating element (20; 40) according to one of claims 1 to 8, characterized in that the projections (24, 25; 45, 46, 47) of the second metal sheets (22, 23; 42, 43, 44) are arranged equidistantly to each other in rows and columns. 08.01.202616 / 18 EM 12506 10. Compensating element (20; 40) according to one of claims 1 to 9, characterized in that all projections (24, 25; 45, 46, 47) of the second metal sheets (22, 23; 42, 43, 44) are identical or differ in their shape and / or dimensions.

11. Compensating element (20; 40) according to one of claims 1 to 10, characterized in that the projections (24, 25) of the second metal sheets (22, 23) have plateau-like contact surfaces with which the second metal sheets (22, 23) lie flat against a respective first metal sheet (21).

12. Compensating element (20; 40) according to one of claims 1 to 11, characterized in that at least one of the second metal sheets (22, 23; 42, 43, 44) has fluid guide openings (26).

13. Electrolysis cell of an electrolysis device, comprising a catalyst-coated membrane (28) arranged between two bipolar plates (29), fluid conduction structures (30) arranged between the catalyst-coated membrane (28) and the bipolar plates (29), and at least one compensating element (20; 40) according to one of claims 1 to 12.

14. Electrolysis cell according to claim 13, characterized in that the compensating element (20; 40) or one of the compensating elements is arranged on a hydrogen side and thus cathode side of the electrolysis cell between the respective fluid conduction structure and the respective bipolar plate. 08.01.202617 / 18 EM 12506 15. Electrolysis cell according to claim 13 or 14, characterized in that the compensating element (20; 40) or one of the compensating elements is arranged on a water side and thus anode side of the electrolysis cell between the respective fluid conducting structure and the respective bipolar plate.

16. Electrolysis cell according to one of claims 13 to 15, characterized in that at least the second metal sheet of the respective compensating element (20; 40) facing the respective fluid guide structure has fluid guide openings (26).

17. Electrolysis device, comprising a cell stack with several electrolysis cells, comprising a force application unit having end plates, wherein the cell stack is arranged and pressed between the end plates, characterized in that the electrolysis cells are designed according to one of claims 13 to 16. January 8, 2026

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