JP7717818B2 - Electrolysis plate for hydrogen production and method for manufacturing the electrolysis plate - Google Patents

Description

The present invention relates to an electrolysis plate suitable for use in an electrolysis apparatus for producing hydrogen. Furthermore, the present invention relates to a method for manufacturing the electrolysis plate.

An apparatus for producing hydrogen using electrolysis is described, for example, in EP 2 507 410. The electrolysis plant described must be adapted to operate with water taken from a saltwater, brackish, or freshwater source. In that case, the water is fed into a carrier gas stream so that at least a portion of the water is entrained in vaporized form within the carrier gas stream. The carrier gas stream fed in this way is ultimately fed to the electrolysis device.

The various electrochemical systems described in WO 2019/121947 and WO 2020/030644 each have an arrangement of multiple separator plates that define fluid chambers. The electrochemical systems described may be fuel cells or electrolyzers.

EP 3725916 A1 discloses an electrolysis plate for use in an apparatus for generating hydrogen, the electrolysis plate having an opening for gas to pass through, the edges of which are coated with a non-conductive material.

EP 3575442 A1 discloses a bipolar electrolytic cell intended for producing hydrogen. The anode and/or cathode of the cell are formed as porous electrodes. The membrane of the bipolar cell is a porous membrane made of an inorganic material. The device according to EP 3575442 A1 must be adapted for alkaline electrolysis.

Methods for incorporating a hydrogen electrolysis system into a more comprehensive system in which energy and/or medium flows occur are described, for example, in WO 2014/144556 and DE 202011102525 A1.

The objective of the present invention is to further develop the production of electrolytic plates compared to the prior art, taking into account production technology aspects as well as fluid technology aspects.

This problem is solved by the present invention by an electrolysis plate according to claim 1, which is adapted in particular for hydrogen electrolysis. Similarly, this problem is solved by a method for manufacturing an electrolysis plate according to claim 10. The embodiments and advantages of the present invention described below in the context of the manufacturing method also apply, within the meaning of the present invention, to this device, i.e., an electrolysis plate, as well as to an electrolysis plant comprising a plurality of such metal plates.

The electrolytic plate includes at least one embossed metal plate, which is shaped to define the flow paths and has individual droplet-shaped embossed elements.

Droplet-shaped, i.e. substantially streamlined, embossed elements in the plan view of the plate surface can be reasonably produced by molding methods and contribute substantially to the mechanical stability of the electrolysis plate. This is particularly important in the case of large-scale electrolysis plants for producing hydrogen. Similarly, the electrolysis plate can be used in fuel cells or redox flow cells.

According to various possible embodiments, each drop-shaped embossing element has a point of maximum embossing depth, the distance of which to one edge of the drop shape is at least 1.2 times and at most 2.4 times the distance to the other edge of the drop shape. Instead of a localized area with a maximum embossing depth, planar areas may also be present in this case, where the embossing depth is continuously greatest. The relationship between the various distances relates to the longitudinal distance between the leading edge of the drop-shaped embossing element and its widest point, on the one hand, and between this widest point and the trailing edge of the embossing element, on the other hand. If the embossing element were considered as a falling drop, the so-called trailing edge of the drop would be at the top. Overall, the embossing elements are endowed with a three-dimensional, streamlined design. Within the embossing structure of the electrolytic plate, all embossing elements may have a uniform shape. Similarly, electrolytic plate embodiments are possible in which various embossing elements exist within the embossing structure.

This allows for proper flow lines, particularly where the fluid is introduced into or discharged from the active field. If various embossing elements of an electrolytic plate are present, these elements may be similar in a geometric sense, i.e., only scaled to the same dimensional ratio. Likewise, embossing elements of the same electrolytic plate may have fundamentally different characteristics, particularly the length-to-width ratio. In both cases, the contour of the embossing element emanating from its end, the so-called front end, which has a shorter distance to the point of maximum protrusion, may be parabolic, for example. Sharp angles are avoided within the embossing element, as well as in the transition between the embossing element and the flat area of the electrolytic plate surrounding the entire surface of the embossing element, in embodiments that are advantageous not only from a fluid engineering perspective but also from a manufacturing perspective. The embossing elements may form a row-column arrangement, with overlapping between the embossing elements in at least one direction. In particular, the rows in which the embossing elements are arranged may overlap, as may the columns formed adjacent to the embossing elements, respectively, in columns. In this way, an embossed structure can be provided in which the electrolytic plate is particularly resistant to bending loads.

There are many possible variations for the arrangement of the droplet-shaped individual embossing elements on the electrolysis plate. In the simplest case, all embossing elements are aligned in the same direction, typically in the desired fluid flow direction. Similarly, variations are possible in which the embossing elements are aligned in alternating rows, i.e., in the longitudinal direction of the metal plate from which the electrolysis plate is produced or in the opposite direction. This variation allows for particularly dense packing of the embossing elements in a given plane, which results in a particularly large total surface area of the electrolysis plate compared to its bottom surface. Alternatively, the embossing elements may be inclined relative to the longitudinal direction of the electrolysis plate. In particular, the embossing elements may form a pattern of at least slightly elongated individual elements, alternating rows and inclined. In particular, a pronounced fluid flow effect can be achieved with such a pattern, in which the inclined embossing elements of a row interlock with adjacent rows of embossing elements that are inclined in the alternating direction.

In a possible development, which can be combined with all of the geometric features of the electrolysis plate described above, one part of the embossing element is formed as a protrusion, while the other part of the embossing element is formed as a similarly shaped recess. This allows identical fluid engineering conditions to be established on both sides of the electrolysis plate. The embossing depth, which is measured separately for each side of the metal plate, i.e., for example, the upper and lower sides in the case of a horizontal configuration, is, in a typical embodiment, at least three times, but not more than ten times, the thickness of the metal plate extended into the unembossed areas of the metal plate. This provides, on the one hand, a highly structured, i.e., embossed, surface relative to the outer dimensions of the electrolysis plate, and, on the other hand, avoids a significant decrease in the material strength in the formed areas of the electrolysis plate.

Inside the manufactured electrochemical cell, a gas diffusion coating may be present on the embossed structure of the electrolysis plate formed by the embossing elements. Regardless of the arrangement of the individual embossing elements, the gas diffusion coating then practically rests flat on the embossed structure, and the droplet-shaped embodiment ensures the desired flow in the direction of the gas diffusion coating throughout the entire embossed area. With regard to the shape and arrangement of the embossing elements, which must be adapted to each individual case, the dynamic pressure is particularly important, and the structure of the electrochemical cell is determined by this dynamic pressure. The electrolysis plate can in particular provide a bipolar plate for the electrochemical device.

Electrolytic plates can be produced in a streamlined manner by forming a metal plate, within which embossed structures are created in the form of separate, droplet-shaped embossed elements spaced apart from one another. This forming can be carried out in particular in a continuous process, for example, a rolling process.

Several embodiments of the present invention are described in more detail below with reference to the drawings.

1 is a diagram of a first embodiment of an electrolysis plate for water electrolysis; FIG. FIG. 2 is a detailed view of the electrolysis plate shown in FIG. 1 . 2 is a cross-sectional view of the electrolysis plate of FIG. 1 including a gas diffusion coating. FIG. 3 is a view similar to FIG. 2 of an alternative embodiment of the electrolysis plate. FIG. 5 is a cross-sectional view of the electrolysis plate shown in FIG. 4. 5 is a diagram of an embossing element of the electrolytic plate according to FIG. 4; 2 is a diagram of an embossing element of the electrolytic plate according to FIG. 1; 10A and 10B are diagrams illustrating alternative configurations of the embossing elements of the embossing structure of the electrolytic plate. 10A and 10B are diagrams showing further possible configurations of the embossing elements of the embossing structure of the electrolytic plate. FIG. 1 is a diagram of an embossing structure consisting of protruding and recessed embossing elements.

The following description relates to all embodiments unless otherwise specified. Parts and features that correspond to each other or that act essentially equally are given the same reference numerals in all figures.

In all embodiments, the electrolytic plate 1 is formed as a formed metal plate 2 having a frame-shaped connection area 3 and a rectangular formed area 4 located within this area 3. The formed metal plate 2 is a steel plate that may be coated.

On the surface of the forming zone 4, a medium, in particular an acidic or alkaline aqueous liquid, flows substantially in the longitudinal direction LR of the formed metal plate 2. The width of the formed metal plate 2 is designated _B2 and the height of the formed metal plate 2 is designated _H2 . The forming zone 4 has a width _B4 and a height _H4 .

Inside the connection area 3, there are openings 6 that allow the medium to pass through and holes 5 that are smaller than the circular openings 6, and by inserting clamp anchors (not shown) through the holes 5, multiple electrolytic plates 1 can be mechanically interconnected within the stack.

The forming area 4 is provided with a shaped feature in the form of an embossed pattern 8. The shaped feature formed as an embossed pattern 8 has a fluid-technical function on the one hand and increases the mechanical stability of the electrolytic plate 1 compared to a flat metal plate on the other hand. The embossed pattern 8 is in the form of individual embossed elements 10, 24 forming rows 7 and columns 9. In this case, each row 7 is arranged transversely to the longitudinal direction LR of the forming area 4, whereas the columns 9 are aligned in the longitudinal direction LR. The gaseous or liquid medium flowing through the forming area 4 flows substantially in the longitudinal direction LR. In Figures 2 and 4, the longitudinal direction LR coincides with the x-direction.

The embossing elements 10, 24 are formed in the shape of droplets, which significantly contributes to the flowable medium flowing in a predominantly layered manner within the active field formed by the embossing pattern 8 and without generating cavitation. The gas diffusion coating on the formed metal plate 2 is indicated at 11.

The extension of each embossing element 10, 24 in the longitudinal direction LR is designated B _10. In contrast, the extension of the embossing element 10, 24 in the transverse direction is designated H _10. The embossing depth of the embossing element 10, 24, whether it is a protruding embossing element 10 or a recessed embossing element 24, is designated H _8. The embossing depth H ₈ is at least three times the metal plate thickness d of the formed metal plate 2, which must be measured within the flat area designated 14 of the metal plate 2.

The embossing elements 10, 24 have a streamlined shape, also referred to as a droplet shape. The leading edge of each embossing element 10, 24 is designated 12, and the trailing edge of each embossing element 10, 24 is designated 13. The leading edge 21 of each embossing element 10, 24, originating from leading edge 12, extends into a trailing edge 22 that extends to the leading edge 13. A point of maximum embossing depth, designated 17, is located at the boundary between leading edge 21 and trailing edge 22. In some embodiments, a uniform embossing depth may be provided over a relatively elongated area, and thus the region of maximum embossing depth 17 is generally referred to as the region of maximum embossing depth. The length of leading edge 21 is designated _L21 , and the length of region 22 is designated _L22 . The sum of the lengths _L21 and L22 of regions 21, ₂₂ corresponds to the elongation _B10 of the embossing elements 10, 24. The length L ₂₁ of the front region 21 measured between the tip 12 and the dotted region 17 is 30-45% of the total extension B ₁₀ of the embossing elements 10, 24 in the longitudinal direction LR.

From the tip 12 emanates a front profile 18 that is at least partially parabolic or approximates the form of a parabola. Sides 19 in the rear region 22, which are part of the outer profile of the embossing elements 10, 24, merge into a rear profile 20 that curves towards the end 13. A finite radius of curvature is provided at each point of the rear profile 20, preventing the embossing elements 10, 24 from discontinuing at the tip in any case.

The row-column arrangement of embossing elements 10, 24 provides overlapping areas 15 between rows 7 and overlapping areas 16 between columns 9. The width of overlapping area 15 is designated U ₁₅ and the width of overlapping area 16 is designated U _16. In the embodiment shown in Figures 1-7, all embossing elements 10 are equally aligned.

The embodiment shown in Figure 8 is distinguished from the embodiments shown in Figures 1 to 7 in that the embossing elements 10 in the first row 9 are aligned in a first direction and the embossing elements 10 in the next row 9 are aligned in the opposite direction. This results in staggered embossing elements 10 in adjacently arranged rows 9. This alignment of the embossing elements 10 has the advantage that a particularly large portion of the forming area 4 can be filled with the embossing elements 10, i.e., the flat areas 14 inside the embossing pattern 8 are minimized. This particularly benefits the mechanical stability of the formed metal plate 2, while at the same time providing favorable fluid engineering properties and maximizing the overall surface of the electrolytic plate 1, which is also advantageous in terms of electrical properties.

In the embodiment shown in Figure 9, all of the embossing elements 10 are inclined relative to the longitudinal direction LR so that, overall, a pattern 23 is formed in which the embossing elements 10 are inclined in alternating rows. The advantage of this configuration is, in particular, that a particularly large contact surface is occupied by the gas diffusion coating.

The embodiment shown in Figure 10 differs from the embodiment shown in Figure 1 by the staggered rows 7, in which the embossing elements 10 are formed as protrusions in one row 7, while in the next row 7 the embossing elements 24 are depressions. The embossing elements 10, 24 protruding in opposite directions from the flat area 14 have the same shape. In Figure 10, there is also an overlap between adjacent rows 7 and between adjacent columns 9.

1 Electrolytic plate 2 Formed metal plate 3 Connection area 4 Forming area 5 Hole 6 Opening 7 Row 8 Embossing pattern 9 Column 10 Embossing elements, protrusions 11 Gas diffusion coating 12 Tip of the embossing elements 13 Rear end of the embossing elements 14 Flat area of the formed metal plate 15 Overlap area between rows 16 Overlap area between columns 17 Area of maximum embossing depth 18 Parabolic front contour 19 Side 20 Curved rear contour 21 Front area 22 Rear area 23 Pattern with embossing elements in inclined position 24 Embossing elements, depressions B ₂ Width of the formed metal plate B ₄ Width of the forming area B ₁₀ Longitudinal extension of the embossing elements d Metal plate thickness H ₂ Height of the formed metal plate H ₄ Height of the forming area H ₈ Embossing depth of the embossing pattern H ₁₀ Lateral extension of embossing element L ₂₁ Length of front region L ₂₂ Length of rear region LR Longitudinal direction U ₁₅ Width of overlapping region between rows U ₁₆ Width of overlapping region between columns

Claims (10)

A plate (1) adapted for hydrogen electrolysis, comprising at least one stamped metal plate (2), the stamped metal plate (2) being formed to define flow channels and having a flat area (14) and individual droplet-shaped stamped elements (10, 24) formed within the flat area (14);
A plate (1), characterized in that one part of the embossing element (10) is formed as a protrusion with respect to the flat area (14) of the metal plate (2), and the other part of the embossing element (24) is formed as a depression formed in the same shape as the protrusion , so that the same fluid conditions are obtained on both sides of the plate (1). 2. The plate (1) according to claim 1, characterized in that each of the drop-shaped embossing elements (10, 24) has a region of maximum embossing depth (17) formed as a localized area, and the distance (L ₂₂ ) of the region of maximum embossing depth (17) to one end (13) of the drop-shaped embossing element (10, 24) is 1.2 to 2.4 times the distance (L ₂₁ ) to the other end (12) of the embossing element (10, 24). The plate (1) according to claim 1, characterized in that each of the droplet-shaped embossing elements (10, 24) has only one point of maximum width of the embossing element (10, 24), and the distance (L ₂₂ ) of the maximum width of the embossing element (10, 24) to one end (13) of the droplet-shaped embossing element (10, 24) is 1.2 to 2.4 times the distance (L ₂₁ ) to the other end (12) of the embossing element (10, 24). 4. A plate (1) according to claim 2 _{or 3} , characterized in that the contour (18) of the embossing element (10, 24) emanating from the end (12) of the embossing element (10, 24) having the shorter distance (L21) to the region (17) of maximum protrusion describes a parabolic shape. A plate (1) according to any one of claims 1 to 4, characterized in that the row-column arrangement of the embossing elements (10, 24) is such that there is an overlap between the embossing elements (10, 24) in at least one direction. The plate (1) according to claim 5, characterized in that the embossing elements (10, 24) are aligned in alternating rows, i.e., aligned in the longitudinal direction (LR) of the metal plate (2) and in the opposite direction, respectively. A plate (1) according to claim 5 or 6, characterized in that the embossing elements (10, 24) are arranged in a pattern (23) that is staggered from row to row. 8. Plate ₍₁ ) according to any one of claims 1 to 7, characterized in that the embossing depth (H8) of the embossing elements (10, 24) is at least three times the thickness (d) of the metal plate (2). Use of a plate (1) according to any one of claims 1 to 8 in an electrolysis device for producing hydrogen. 1. A method for manufacturing a plate (1) adapted for hydrogen electrolysis, comprising shaping a metal plate (2) in which an embossed pattern (8) is produced in a continuous process in the form of separate, droplet-shaped embossed elements (10, 24) spaced apart in a flat area (14) of the metal plate (2),
A method in which one part of the embossing element (10) is formed as a protrusion and the other part of the embossing element (24) is formed as a depression formed in the same shape as the protrusion, relative to the flat area (14) of the metal plate (2), so that the same fluid conditions are obtained on both sides of the plate (1 ).