PERFORATED PLATE STRUCTURE, SUCH AS AN ELECTRODE

Abstract

A plate structure, such as a plate electrode, comprising two outer layers and an intermediate layer. Both outer layers are provided with a pattern of recesses, such as hexagonal or circular recesses. The recesses on one outer layer are offset with respect to the recesses in the other outer layer. The intermediate layer comprises through-holes, each through-hole connecting a recess at one outer layer with a partially overlapping recess at the opposite outer layer.

Claims

1. A plate structure comprising two outer layers and at least one intermediate layer, wherein both outer layers are provided with a pattern of recesses, the recesses on one outer layer being offset with respect to the recesses in the other outer layer, and wherein the at least one intermediate layer comprises through-holes, each said through-hole connecting one said recess at one said outer layer with one said partially overlapping recess at the opposite outer layer.

2. The plate structure according to claim 1, wherein the recesses at the outer layers are of equal size, shape and spacing, separated by partitions of even thickness, wherein the partitions join each other at junctions between three or four adjacent said recesses.

3. The plate structure according to claim 2, wherein the junctions of the partitions of one said outer layer are aligned with centers of the recesses of the opposite outer layer.

4. The plate structure according to claim 3, wherein each recess at one said outer layer partly overlaps at least three adjacent recesses of the opposite outer layer, and the through-holes are formed where one said recess of one said outer layer overlaps a one said recess of the opposite outer layer.

5. The plate structure according to claim 1, wherein the recesses include circular, square and/or polygonal recesses.

6. The plate structure according to claim 1, wherein the through-holes have a diameter of at least 10 micrometers.

7. The plate structure according to claim 1, wherein the largest width of the recesses is in a range of at most 2 mm.

8. The plate structure according to claim 1, having a thickness in a range of at most 2 mm.

9. The plate structure according to claim 1, wherein the structure is made of a plastic material or a metal plate.

10. The plate structure according to claim 1, having planar outer surfaces.

11. An electrolyzer comprising an anode and/or cathode formed by the plate structure according to claim 1.

12. A method of manufacturing a plate structure according to claim 1 comprising a step of etching.

13. The method according to claim 12, wherein the recesses are etched until a depth where the through-holes appear.

14. The plate structure according to claim 5, wherein the recesses comprise hexagonal recesses.

15. The plate structure according to claim 7, wherein the largest width of the recesses is in a range of at most 1 mm.

16. The plate structure according to claim 7, wherein the largest width of the recesses is in a range of at most at most 100 microns.

17. The plate structure according to claim 7, wherein the largest width of the recesses is in a range of. at most at most 10 microns.

18. The plate structure according to claim 1, wherein the plate structure has a thickness in a range of. at most 1 mm.

19. The plate structure according to claim 1, wherein the plate structure has a thickness in a range of. at most 100 microns.

20. The plate structure according to claim 9, wherein the structure is made of a material selected from the group consisting of corrosion resistant steel, nickel, titanium, niobium or alloys thereof.

Description

[0022] The invention is further explained with reference to the accompanying drawings showing exemplary embodiment.

[0023] FIG. 1: shows a section of a plate structure according to the invention;

[0024] FIG. 2: shows a cross section of the structure along line I-I in FIG. 1.

[0025] FIGS. 3A-G: show consecutive steps of a micro-etching process for manufacturing the plate structure of FIG. 1.

[0026] FIGS. 1 and 2 show a metal plate structure 1 comprising two outer layers 2, 3 and an intermediate layer 4. In FIG. 1, the pattern of the outer layer 2 facing the viewer is represented in drawn lines, while the pattern of the opposite outer layer 3 is drawn in dashed lines.

[0027] In the shown exemplary embodiment, both outer layers 2, 3 are provided with a honeycomb pattern of hexagonal recesses 5. In the shown embodiment, the recesses 5 at the two outer layers 2, 3 are of equal size, shape and spacing, and are separated by partitions 6 of even thickness. In alternative embodiments, the outer layers 2, 3 can have different thicknesses and/or the recesses may have varying geometries. The partitions 6 join each other at junctions 7 between three adjacent recesses 5. This results in a very dense arrangement of recesses 5 and, consequently, in a very high specific surface area. The recesses 5 on one outer layer 2 are offset with respect to the recesses 5 of the opposite outer layer 3, in such a way that junctions 7 of the partitions 6 of one outer layer 2 are aligned with the centers of the recesses 5 of the opposite outer layer 3.

[0028] The plate structure 1 has plane outer surfaces interrupted only by the recesses 5.

[0029] The intermediate layer 4 comprises through-holes 8. Each through-hole 8 connects a recess 5 at one outer layer 2 with a partially overlapping recess 5 at the opposite outer layer 3.

[0030] The outer layers 2, 3 and the intermediate layer 4 integrally form a single plate of a single metal or metal alloy material.

[0031] FIGS. 3A-F show consecutive steps of a micro-etching process for manufacturing the perforated metal plate structure 1. A starting plate or sheet 1′ of nickel, a nickel alloy, a corrosion resistant steel or any other suitable etchable material, is first cleaned, typically in a clean room, in order to optimize adhesion to a layer 10 of a light-sensitive photoresist material, applied in a next step on both sides of the plate 1′ (FIG. 3B). The photoresist material is exposed to actinic radiation, in particular to UV light, and subsequently washed with a photoresist developer. The remaining part of the photoresist images the desired pattern of partitions 6.

[0032] Using Laser Direct Imaging (LDI) technology (reschematically represented by arrows I in FIG. 3C), laser sources directly image a desired pattern of cured photoresist material 11 on both sides of the plate 1′. The imaged pattern at one side of the plate is identical to the pattern at the other side, but offset. If a negative photoresist is used, then the photoresist cures where it is affected by the laser beam, but the other parts 12 of the photoresist remains removable by means of a photoresist developer.

[0033] In a next step (FIG. 3D) the plate 1′ is washed to remove the uncured parts 12 of the photoresist. The cured parts 11 of the photoresist remain and reflect the honeycomb pattern of the partitions 6 of the perforated plate structure 1 to be made.

[0034] In a next step (FIG. 3E), an etching fluid is sprayed over both sides of the plate 1. The cured photoresist 11 is resistant to the etching fluid and shields the metal directly underlying the cured photoresist parts. The etching fluid etches the hexagonal recesses 5, which gradually grow deeper. At a certain depth of the hexagonal recesses 5, through-holes 8 will occur connecting a hexagonal recess 5 at one side of the plate with an overlapping hexagonal recess 5 at the opposite side of the plate 1 (FIG. 3F). In a final step (FIG. 3G), the cured photoresist 11 is washed away, and the desired perforated plate structure 1 is ready. Optionally, it can be treated further, e.g., by applying a coating enhancing catalytic activity or enhancing specific surface area.