SEALING ARRANGEMENT FOR ELECTROCHEMICAL CELLS OF THE PEM TYPE

Abstract

A sealing arrangement is provided for an electrochemical cell. The sealing arrangement includes a metallic plate (7) and a seal (18, 19) which is arranged thereon and which forms at least one closed sealing ring, which is arranged on the plate (7). A peripheral inner support structure (20, 22) supports the seal (18, 19) to the inside and an outer support structure (21, 23) supports the seal (18, 19) to the outside. The support structures are formed of sintered metal and are materially connected to the plate (7).

Claims

1. A sealing arrangement for an electrochemical cell of a proton exchange membrane (PEM) construction the sealing arrangement comprising a metallic plate; and a seal arranged on the plate and which forms at least one closed sealing ring which is arranged on the plate, a support structure formed of sintered metal and materially connected to the plate, the support structure comprising at least one of: a peripheral inner support structure which supports the seal to an inside and an outer support structure which supports the seal to an outside.

2. A sealing arrangement according to claim 1, further comprising another seal, wherein the seals are arranged at both sides of the plate and on each side form at least one closed sealing ring which is arranged on the plate, wherein the peripheral inner support structure which supports the respective seal to the inside and the outer support structure which supports the respective seal to the outside is formed on each side of the plate.

3. A sealing arrangement according to claim 1, wherein the plate is comprised of sintered metal and is manufactured in a 3D printing method.

4. A sealing arrangement according to claim 1, wherein the seal fills out a region between the inner support structure and the outer support structure and bears directly on the plate at least in the region between the support structures.

5. A sealing arrangement according to claim 1, wherein the seal covers the support structure.

6. A sealing arrangement according claim 1, wherein the support structure comprises an annularly peripheral bead.

7. A sealing arrangement according to claim 6, wherein the support structure and/or the seal in regions in which channels are formed are configured to be flatter than in other regions or is interrupted.

8. A sealing arrangement according to claim 1, wherein the support structures on sides which face one another are formed tapering, with a ramp shape, at a distance to one another.

9. A sealing arrangement according to claim 1 further comprising another seal, wherein the seals are arranged at both sides of the plate wherein the seal at a side which is away from the plate has a plane form and/or the other seal at a side which is away from the plate comprise sealing lips.

10. A sealing arrangement according to claim 1, wherein the seal is formed by way of injecting on after the manufacture of the associated support structures.

11. A sealing arrangement according to claim 1, wherein the plate is formed by a foil section.

12. A sealing arrangement according to claim 1, wherein the support structures are manufactured with a 3D printing method.

13. A sealing arrangement according to claim 1, wherein the support structures are deposited onto the plate in a screen printing method.

14. A sealing arrangement according to claim 1, wherein the support structures are formed by way of sintering.

15. A sealing arrangement according to claim 1, wherein the support structures are connected to the plate by way of sintering.

16. A sealing arrangement according to claim 1, wherein the support structure is deposited onto or brought into a plastic foil as a carrier, wherein the plastic foil is arranged on the plate and is removed upon sintering.

17. A sealing arrangement according to claim 1, wherein the plate is comprised of titanium and has a thickness of 0.2 to 0.5 mm.

18. A sealing arrangement according to claim 1, wherein the plate is comprised of stainless steel and has a thickness of 0.1 to 0.2 mm.

19. A sealing arrangement according to claim 1, wherein the support structure has an extension perpendicular to the plate of 0.2 to 1.2 mm.

20. A sealing arrangement according to claim 1, wherein the support structure is configured as a bead with a bead width of 0.2 to 2.0 mm.

21. A sealing arrangement according to claim 8, the part of the support structure which tapers with a ramp shape has a width of 0.5 to 7 mm.

22. A sealing arrangement according to claim 1, wherein the support structures have an average bead distance of 1.5 to 15 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the drawings:

[0032] FIG. 1 is a plan view of a sealing arrangement according to the invention;

[0033] FIG. 2 is an enlarged schematic representation, a section through an electrolysis cell of a cell stack; and

[0034] FIG. 3 is an enlarged schematic sectioned representation, the metallic plate in the region of the seals and support structures.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] Referring to the drawings, the seal arrangement which is represented by way of the figures is part of an electrochemical cell whose construction is represented schematically in FIG. 2. The subsequently described embodiment relates to a sealing arrangement for an electrolysis cell for generating hydrogen and oxygen from water amid the application of electrical energy. It is to be understood that given the application of other media or given a reversal of the process (fuel cell), the basic construction of the electrochemical cell is unchanged, but various modifications be they concerning the applied materials or their arrangement are necessary.

[0036] Such electrochemical cells are constructed into cell stacks, so-called stacks, in which a multitude of such cells are typically connected electrically in series and are arranged lying on one another, wherein the cell stack is held mechanically by way of tie elements and channels for feeding and discharge media are provided within the cell stacks. These channels pass through the stack in a perpendicular manner, in order to connect each individual cell to the respective media feed and discharge. The basic construction of such cell stacks is counted as belonging to the state of the art and is therefore not described in any detail. In this context, however in particular for example DE 10 2017 108 413 A1 is referred to, wherein such a construction is described in detail.

[0037] Each cell 1, as is illustrated in the sectioned representation according to FIG. 2, comprises a bipolar plate 2 which forms channels to both sides. Thus channels 3 are formed on the upper side which is represented in FIG. 2 and channels 4 on the lower side. The upper side is the side which leads water and oxygen on operation, wherein the lower side forms the hydrogen-leading side. A resilient element 6 which is formed by an expanded metal but can also be configured in another manner connects onto the bipolar plate 2 in the active region of the cell 1 which is characterized at 5 in FIG. 1.

[0038] This resilient element 6 which in FIG. 2 bears with its upper side on the bipolar plate 2, at the lower side bears on a plate 7 which is part of the sealing arrangement 8. This plate 7 in the active region 5 of the cell 1, this in the middle region 5 is configured as a perforated plate and the actual sealing arrangement 8 is formed in the edge region. This plate 7 bears on a media-permeable layer 9 which is denoted as a porous transport layer (PTL), in the active region 5. This gas-permeable layer lies in front of a proton-permeable membrane 10 which in the active region 5 of the cell 1 is also provided with such a media-permeable layer 11 at the rear side. The membrane 10 in a manner known per se is coated with electrodes at both sides, said electrodes acting as catalyzer. In turn, a bipolar plate 2 which is not shown in FIG. 2 and which forms part of the electrolysis cell which connects thereto connects at the bottom onto this media-permeable layer 11. The construction of the cell is such that the media are fed and discharged through the channels 3 and 4 and can come onto the membrane 10 is a surfaced manner, and specifically in the active region 5 of the cell 1

[0039] The components 6, 7, 9 and 11 however not only need to be media-permeable, in order to be able to lead the reactants onto the membrane 10 or away from this, they must also be able to electrically conduct, in order to feed the current which is necessary for the reaction. The contacting is effected in each case via a bipolar plate 2. In the represented embodiment therefore the bipolar plate 2, the resilient element 6, the plate 7 and media-permeable layer 11 are formed from titanium, and specifically the bipolar plate 2 by way of an embossed sheet, the resilient element 6 by way of a sheet which is configured in the manner of an expanded metal, the plate 7 by a titanium foil and the media-permeable layer 11 by a knitted fabric, similar to a felt, which is manufactured from titanium fibers. The media-permeable layer 9 is formed from a carbon non-woven.

[0040] As is evident from FIG. 1, the active region 5 of the cell 1 is to be differentiated from the edge 12 which is used for the channel formation and for fastening the cells amongst one another. Channels 13, 14, 15 and 16 via which the media feed and discharge is effected and which run perpendicularly through the stack of cells are formed in this edge 12. Furthermore, recesses 17 are formed in the corner regions and are provided for leading through clamping bolts, with which the cell stack is pressed together and held. Further recesses for tie rods can be provided in the edge region.

[0041] As FIG. 1 illustrates, the sealing arrangement 8 is peripheral in the edge 12, thus is configured as a closed ring. This closed ring surrounds the channels 13 to 16 to the outside. Furthermore, this sealing arrangement comprises rings which are closed per se and which surround the channels 13 to 16 and surround the active region 5. In sections, the last ring is reduced in height, in order to connect the channels 3 of the respective cell 1 to the channels 14 and 16 which run perpendicularly in the stack. The supply with water as well as the discharge of the arising oxygen is effected via the channels 14 and 16.

[0042] The connection of the hydrogen-side space which amongst other things is formed by the channels 4 and free spaces in the resilient element 6 is effected by way of the seal 18 being sunk in the regions which are adjacent to the channels 13 and 15, in order to create a channel connection for the discharge of the hydrogen here. The peripheral seals 18 and 19 which surround the channels 13 to 16 to the outside in contrast are configured in a continuously bearing manner and seal the respective cell to the outside.

[0043] This sealing arrangement 8 as FIGS. 2 and 3 shows comprises a seal 18 which is at the top in the figures and which seals with respect to the bipolar plate 2 and a lower seal 19 which seals with respect to the membrane 10. These seals 18, 19 consist of fluorinated rubber and are injected on.

[0044] The seal 18 on the upper side of the plate 7, towards the inside, thus to the channels 13 to 16 is surrounded by a peripheral inner support structure 20 and to the outside by an outer support structure 21. The seal 19 on the lower side accordingly comprises an inner support structure 22 and an outer support structure 23. Each support structure (20-23) consist of a peripheral bead 24 and a region 25 which tapers in a ramp-like manner and in a manner connecting laterally into the region below the seal 18 and 19 respectively. The ramp-shaped region 25 of each support structure starting from the bead 24 extends at roughly half the height up to the plate 7 in a manner tapering to the opposite bead 25. A free space in which the seal 18 and 19 respectively bears directly on the plate 7 is formed between the tapering regions 25.

[0045] The plate 7 which with regard to the represented embodiment consists of a titanium foil has a thickness 26 of 0.3 mm. The support structures 20 to 23 which extent at both sides of the plates each comprise a peripheral bead 24 which has an extension 27 perpendicular to the plate 7 of 0.6 mm. The width 28 of a bead 24 with the represented embodiment is 1 mm, the width 31 of the part 25 which tapers in a ramp-like manner 1.5 mm. The average distance 29 of the beads 24 of the inner structure 20 and 22 respectively and of the outer structure 21 and 23 respectively is 8 mm.

[0046] Concerning the represented embodiment, the plate 7 is formed from a titanium foil which is configured in a perforated manner in the active region 5, in order to be media-permeable. The support structures 20 and 21 at the upper side and 22 and 23 at the lower side are created with 3D printing and likewise consist of titanium. The connection amongst one another and to the plate 7 is formed by sintering. Herein, the manufacture can be different, as has been initially specified.

[0047] After the plate 7 is formed with the support structures 20 to 23 which are located thereon, the upper seal 18 and the lower seal 19 are manufactured with the injection molding method. Herein, the seals bear directly on the plate 7 in the region between the tapering, ramp-like regions 25. With regard to the present embodiment variant, the seals completely cover the beads. 24. Whereas the lower seal 19 has a plane lower side as a sealing side which has a small distance to the beads 24 of the support structure 22 and 23 respectively, the upper seal 18 comprises an upper side which is wave-like in cross section, thus sealing side, wherein the wave troughs lie at roughly the height of the upper side of the seal in the region of the beads 24 and form the sealing lips 30 which run around the wave peak 30 and which are significantly elevated with respect to these.

[0048] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMERALS

[0049] 1 cell [0050] 2 bipolar plate [0051] 3 channels [0052] 4 channels [0053] 5 active region of the cell [0054] 6 resilient element [0055] 7 plate [0056] 8 sealing arrangement [0057] 9 media-permeable layer [0058] 10 membrane [0059] 11 media-permeable layer [0060] 12 edge of the plate 7 [0061] 13 perpendicular channels [0062] 14 perpendicular channels [0063] 15 perpendicular channels [0064] 16 perpendicular channels [0065] 17 recesses [0066] 18 seal top [0067] 19 seal bottom [0068] 20 inner support structure top [0069] 21 outer support structure top [0070] 22 inner support structure bottom [0071] 23 outer support structure bottom [0072] 24 bead [0073] 25 region tapering in a ramp-like manner [0074] 26 thickness of the plate 7 [0075] 27 height of the bead 24 [0076] 28 width of the bead 24 [0077] 29 average bead distance [0078] 30 sealing lips [0079] 31 width of the region which tapers in a ramp-like manner