SEPARATOR PLATE, AND DIE PAIR AND METHOD FOR PRODUCING SUCH A SEPARATOR PLATE

Abstract

A separator plate for an electrolyser, to a method for producing same, and to a die pair for producing such a separator plate and for carrying out said method. A separator plate for an electrolyser, having a first metal layer, the separator plate comprising an active region having at least one multitude of flow channels for a reaction medium. The flow channels being embossed into the first metal layer and having a channel bottom and channel walls arranged on both sides of the channel bottom. Webs are arranged between adjacent channel walls of adjacent flow channels. At least some of the channel bottoms of the multitude of flow channels, the surface of the first metal layer opposite the channel bottom is at least partially substantially planar in a cross-section transverse to the direction of extension of the respective flow channel.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to German Utility Model Application No. 20 2022 107 287.6, entitled “SEPARATOR PLATE, AND DIE PAIR AND METHOD FOR PRODUCING SUCH A SEPARATOR PLATE”, and filed on Dec. 29, 2022. The entire contents of the above-listed application is hereby incorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates to a separator plate for an electrolyser, to a method for producing same, and to a die pair for producing such a separator plate and for carrying out said method.

BACKGROUND AND SUMMARY

Electrolysers are usually formed of a stack of electrochemical cells. The electrochemical cells of an electrolyser comprise a separator plate, a membrane arranged therebetween, and a porous transport layer, PTL, between the membrane and the adjacent separator plates on each side thereof. The porous transport layer bears against a separator plate, which is constructed from at least one metal layer.

In the case of electrolysers, the separator plates are usually made of stainless steel or titanium, wherein these layer materials may additionally be partially or fully coated. The porous transport layer (PTL) is in turn typically made of titanium, with additional coatings of the PTL also being possible here in order, for example, to lower the contact resistance in relation to the separator plate or to increase the corrosion resistance of the PTL.

The separator plate of an electrolyser, which is usually a single-layer separator plate, comprises an active region which has a multitude of flow channels embossed into the metal layer of the separator plate. By way of example, a reaction medium is fed into or discharged from these flow channels. In the case of electrolysers, usually inbound flow channels are provided for water, and outbound flow channels are provided for water and oxygen as well as flow channels for hydrogen, wherein the flow channels for oxygen and for hydrogen are arranged on opposite sides of the membrane and thus also of the PTL. The separator plates may also comprise active regions in which the reaction media (reactants and products) are respectively guided, and in which the electrochemical reaction for the electrolysis of water takes place. All these regions each have a multitude of flow channels which have channel walls adjacent to their channel bottom, wherein webs are arranged in each case between adjacent channel walls, so that the channel walls at the same time form the outer walls of the webs. The regions that comprise a multitude of flow channels therefore contain a sequence of channels in the form of grooves and webs located between the grooves.

The PTL bears against the webs of the separator plate and is supported by the webs. The problem here is that the PTL itself has only low mechanical stability, and the webs of the separator plate often have rounded surfaces on the side thereof facing towards the PTL. As a result, the PTL only bears against small portions of the separator plate and is only supported by these small portions of the separator plate. For instance, the ratio between unsupported areas and supported areas of the PTL is large and consequently unfavourable.

The problem addressed by the present disclosure is that of providing a separator plate and a method for producing same, as well as a die pair for carrying out this production method, in which the bearing of the PTL against the webs of a region containing a multitude of flow channels is improved.

The above problems are addressed embodiments of separator plates, die pairs, an the methods described herein.

The separator plate according to the present disclosure for an electrolyser has at least a first metal layer. Provided in this first metal layer is an active region having at least one multitude of flow channels for a reaction medium, said flow channels being embossed into the first metal layer. The flow channels are configured in the form of grooves having a channel bottom and channel walls arranged on both sides of the channel bottom. Webs are arranged between channel walls of adjacent flow channels of the multitude, so that the multitude of embossed flow channels of the active region forms a sequence of grooves and webs.

According to the present disclosure, it is now provided that, for one, some or all of the channels of the multitude of flow channels, the surface of the first metal layer opposite the channel bottom is at least in part substantially planar in a cross-section transverse to the direction of extension of the respective flow channel, e.g. over the width thereof.

Due to this design, which differs from the prior art, of the surfaces of the webs located between the channels that are opposite the channel for a reaction medium, it is possible to mount a PTL on these webs, wherein said PTL bears with a greater surface area against the metal layer so that the support of the PTL is improved and at the same time the ratio between the unsupported area of the PTL and the supported area of the PTL is reduced. The resulting effect is that the combination of the separator plate according to the present disclosure with a PTL is mechanically more stable.

For one, some or all of the channels of the multitude of flow channels, the substantially planar region of the surface opposite the channel bottom may advantageously have a width BE, determined transversely to the direction of extension of the respective flow channel, for which the following applies in relation to the original sheet thickness BA of the active region of the first metal layer before the active region is embossed: 1.5 BA≤BE≤4 BA, 2 BA≤BE and/or BE≤3 BA. Such a design of the separator plate results in a high proportion of supported areas of the separator plate.

A region is substantially planar, for example over the abovementioned width BE, if the surface of the first metal layer opposite the channel bottom is at a substantially or completely constant distance from a line connecting two points of the channel bottom that have the maximum depth of the channel, said line extending transversely to the direction of extension of the respective channel. In this case, where an equal distance means that the distance fluctuates by ≤5%, ≤2%, and/or ≤1%, then the surface opposite the channel bottom is substantially planar over the width BE.

For instance, a substantially constant distance is given if, over the width BE, the surface opposite the channel bottom is at a distance AO from the aforementioned straight line and, over the width BE, the distance AO varies around the mean value of AO by at most half of the maximum distance of the channel bottom from the straight line connecting the two points of maximum depth.

It is also advantageous if perpendicular to the direction of extension of a channel the central axes of adjacent channels have a spacing AK, for which the following applies: 7 BA≤AK≤13 BA, and/or 9 BA≤AK≤11 BA. A substantially planar surface of a web may be formed if the channel bottom of an adjacent flow channel on the other side of the metal layer is at least partially convex, such as over the width BE. In other words, a channel bottom is convex and a web surface directly opposite the channel bottom on the other side of the metal layer is substantially planar.

In the present disclosure, it is essential that the design of the channel bottom and of the opposite surface of the metal layer is produced in a shape using a method, as described according to the present disclosure.

The present disclosure also encompasses a method for producing an above-described separator plate, wherein, in a single-stage or multi-stage forming process, the first metal layer is formed using a male die and a female die as a die pair, wherein, for at least one, some or all of the surfaces that are at least partially substantially planar following the forming process, the structures that form the active region of the separator plate on one of the dies have a free space, for instance a concave depression, and the structures on the other die that are opposite said forming structures on the aforementioned die during the forming of the first metal layer are cambered, for example convex.

The present disclosure also encompasses a die pair that can be used for said method, in which, for at least one, some or all of the surfaces that are at least partially substantially planar following the forming process, the structures that form the active region of the separator plate on one of the dies have a free space, for example a concave depression, and the structures on the other die that are opposite said forming structures on the aforementioned die during the forming of the first metal layer are cambered, for example convex.

In this die pair, advantageously one, some or all of the cambered structures have an elevation U beyond the regions of the die adjacent to the respective cambered structure in a cross-section perpendicular to the direction of extension of the respective flow channel of the active region, where 10 μm≤U≤150 μm, advantageously 40 μm≤U≤80 μm.

Furthermore, in this die pair, advantageously one, some or all of the cambered structures have an elevation U beyond the regions of the die adjacent to the respective cambered structure in a cross-section perpendicular to the direction of extension of the respective flow channel of the active region, where U≥0.05 BA, advantageously U≥0.12 BA.

In the method for producing a separator plate, as explained above, a metal layer may be formed, for example, in a roller embossing process.

The separator plate according to the present disclosure may also be produced by roll-forming the first metal layer, wherein the production method uses a die according to the present disclosure. For instance, the forming of the first metal layer may take place in a single-stage or multi-stage embossing process.

Individual examples of dies and separator plates according to the present disclosure are shown below. Identical and similar reference signs are used for identical and similar components, and therefore the description thereof will not be repeated in full. The following examples show not only the essential features of the present disclosure, but also additional optional features which can each be used to further develop the present disclosure. However, it is also possible to use several of the features presented below to further develop the present disclosure or also to combine these with additional optional features of the same example or other examples.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a die pair for producing a separator plate from the prior art.

FIG. 2 shows, in cross-section, a detail view of a separator plate produced using the die from FIG. 1.

FIG. 3 shows a die pair according to the present disclosure for producing a separator plate.

FIG. 4 shows, in cross-section, a detail view of a separator plate produced using the die pair from FIG. 3.

FIG. 5 shows a detail view of two further separator plates.

FIG. 6 shows a detail view of another separator plate.

FIG. 7 shows a detail view of another separator plate.

FIG. 8 shows a detail view of another separator plate.

FIG. 9 shows, in cross-section, a detail view of a die pair.

FIG. 10 shows, in cross-section, another detail view of the die pair from FIG. 9.

FIG. 11 shows, in cross-section, another detail view of the die pair from FIG. 10.

DETAILED DESCRIPTION

FIG. 1 shows, in cross-section, a detail view of a die pair 1 comprising a female die 2 and a male die 3 for embossing a metal layer of a separator plate, as shown in the subsequent FIG. 2 as a metal layer 11 of a separator plate 10. Formed in the female die 2 are embossing structures 4 comprising concave depressions (grooves) 6a and 6b, by which webs can be embossed into the metal layer, and convex structures (webs) 7a and 7b, by which grooves can be embossed into the metal layer. Complementary embossing structures 5 are arranged in the male die 3, comprising grooves 8a and 8b and convex structures 9a and 9b.

Typically, in a die pair as shown in FIG. 1 and as used in the prior art, the web surfaces of the embossing structures 7a, 7b, 9a and 9b and the bottoms of the grooves 6a, 6b, 8a and 8b are largely horizontal.

FIG. 2 shows, in cross-section, a detail view of a separator plate 10, wherein the cross-section through the separator plate 10 corresponds to the cross-section used in FIG. 1 to illustrate the die pair 1. The separator plate 10 in FIG. 2 comprises a single metal layer 11 having an active region 12, shown in a detail view here, in which the electrochemical reaction takes place in a stack of separator plates of an electrolyser. In this active region 12, channels are embossed into both sides of the metal layer 11 by the die pair 1, of which the channels 13a, 13b and 13c are shown. The channels 13a and 13b are located on the same side of the separator plate 10, and on the opposite side of the separator plate 10 form webs with surfaces 17a, 17b. These surfaces 17a, 17b are respectively opposite a channel bottom 14a and 14b of the channel 13a and 13b and form the surface of webs 16a and 16b. A channel wall 15a and a channel wall 15a′ are formed adjacent to the channel bottom 14a. Correspondingly, a channel wall 15b and a channel wall 15b′ are formed adjacent to the channel bottom 14b. The channel walls 15a′ and 15b in turn form a web 16c between them.

When using a female die and a male die as the die pair 1, as shown in FIG. 1, the channel bottoms 14a and 14b are largely horizontal, while the surfaces 17a and 17b opposite the channel bottoms 14a and 14b are formed in a convexly curved or rounded manner during the embossing process. The problem here is that the surfaces 17a and 17b only form a small bearing surface for a porous transport layer (PTL) arranged adjacent thereto, so that the PTL is only supported over a small portion of its surface by the separator plate 10.

FIG. 3 shows, in cross-section, a die pair according to the present disclosure. The following description relates entirely to a cross-section as shown in FIG. 3. In the case of this die pair, the same reference signs are used for the same elements and similar reference signs are used for similar elements to those in FIG. 1. In a manner differing from the die pair 1 in FIG. 1, the webs 7a, 7b, 9a and 9b are now configured differently than the corresponding structures in the die pair 1 of FIG. 1. For instance, the webs 7a, 7b, 9a and 9b have free spaces, so that the webs have a free space X, for example are concave, in their web top. The grooves 6a, 6b, 8a and 8b of the respective other die, which are located opposite the webs in the respective other die, are correspondingly cambered, for example convex, in their groove bottom so that they have a camber Y or an elevation U. When the metal layer of a separator plate for an electrolyser is embossed using a die pair 1 as shown in FIG. 3, the material that is shifted or displaced during the embossing of the metal layer can thus flow into the free spaces in the webs of the respective die surface. This enables the opposite surface of the opposite groove to emboss the metal layer 11 across its full width, and thus to create a substantially planar surface. By virtue of the camber Y, the first metal layer 11 is embossed in such a way that the rebound of the first metal layer in these regions when the first metal layer 11 is removed from the die 1 is at least partially or fully compensated. The depth of the free space X and the height of the elevation U may be determined absolutely or, to further improve the shape of the channels, may be adapted to the layer thickness of the metal layer 11 and to the width, depth and/or spacing of the channels 13a, 13b, 13c, etc. to be embossed.

FIG. 4 shows, in cross-section, a detail view of a metal layer 11 of a separator plate 10 for an electrolyser that has been embossed using a die as in FIG. 3, the cross-section corresponding to the cross-section shown in FIG. 3. The surfaces 17a, 17b and 17c of the webs 16a, 16b and 16c opposite the respective channel bottom 14a, 14b and 14c are substantially planar, whereas in the case of the separator plate 10 comprising a metal layer 11 shown in a detail view in FIG. 2 the webs 16a, 16b and 16c are convex at their surfaces 17a, 17b and 17c. And the channel bottoms 14a, 14b and 14c are convex in FIG. 4, whereas the channels 13a, 13b and 13c in FIG. 2 have a planar channel bottom 14a, 14b and 14c. Adjacent to the convex elevation of the channel bottom, at the transition from the channel bottom to the adjacent channel walls, here for example 15a, 15a′ or 15b, 15b′ or 15c, 15c′, there are points 23a, 23a′ or 23b, 23b′ or 23c, 23c′ at which the channel 13a, 13b or 13c has a maximum depth.

Due to the planar design of the surface opposite the channel bottom in each case, here for example 17a, 17b and 17c, a sequence of substantially planar surfaces, in this example surfaces 17a, 17b and 17c, is provided on at least one side, in the present example on both sides, of the separator plate 10; these surfaces form a broad bearing surface for a PTL. Due to these broad bearing surfaces, the PTL is better supported by the separator plate 10. For instance, the ratio between supported portions of the PTL and unsupported portions of the PTL for bridging over the channels 13a, 13b and 13c is increased. For instance, the distance freely spanned by the PTL without any bearing and support surface is reduced, this distance corresponding to the width of the channels 13a, 13b or 13c.

FIG. 5 shows, in sub-figures A and B, two further separator plates 10 that have been embossed according to the present disclosure, similar to the one in FIG. 4. This example shows that too little embossing (under-embossing) of the separator plate 10 leads to a separator plate 10 in which, as in FIG. 5A, the surfaces 17a, 17b and 17c are convex but still form a substantially planar bearing surface for a PTL. FIG. 5B shows a separator plate in which the separator plate has been over-embossed, so that the surfaces 17a, 17b and 17c opposite the channel bottoms 14a, 14b and 14c are concave. In this case, too, a substantially planar bearing surface for the PTL is formed by the surfaces 17a, 17b and 17c, as will be explained in FIGS. 7 and 8.

FIG. 6 shows a separator plate 10 comprising a metal layer 11, similar to that in FIG. 4. The detail selected here in this figure is wider, so that not every web and not every channel is provided with its own reference sign; instead, only the channels 13a to 13e and the webs 16a to 16e have been provided with reference signs. The original sheet thickness BA (reference sign 19) can be seen at the left-hand edge of the illustrated separator plate 10.

FIG. 7 shows a detail view of the separator plate 10 from FIG. 4. This figure shows the respective dimensioning of the channels 13a, 13b and 13c. Reference sign 18 denotes the central axis of the respective channel bottom 14a, 14b and 14c once the metal layer 11 has been embossed according to the present disclosure. In this example, the middle of the respective channel bottom is determined as the middle between the points with the maximum depth of the channel, here the two points 23a, 23a′ of the channel 13a for example. Reference sign 20 denotes the distance BE between two points 23a and 23a′ or 23b and 23b′ or 23c and 23c′. Reference sign 21 denotes the depth H of the channel 13a, 13b and 13c in the middle of the respective channel, here the channel 13c for example, said middle being determined across the width of the respective channel in cross-section, as described above.

Reference sign 22 denotes the spacing AK between the central axes (reference sign 18) of two channels arranged immediately adjacent to each other on one side of the separator plate 10, here the channels 13a and 13b. This is therefore the period of the channels in the separator plate 10 on each side of the separator plate 10.

FIG. 8 shows another detail view of the separator plate in FIG. 7, now using the example of the channel 13c. The two points of maximum depth 23c and 23c′ of the channel 13c, between which the channel bottom 14c extends in a convexly curved manner, can be connected by a straight line 24. The distance AG of the channel bottom 14c from this line 24 is denoted by reference sign 26, while the distance AO between the line 24 and the surface 17c opposite the channel bottom 14c is denoted by reference sign 25. The surface 17c is substantially planar according to the present disclosure if, over the entire width BE (reference sign 20), it is at a distance AO (reference sign 25) from the straight line 24 that deviates from the mean value of all the distances AO over this width BE (reference sign 20) by at most half of the maximum distance AG by which the channel bottom 14c between the two points 23c, 23c′ is spaced apart from the line 24, e.g. usually at the middle of the channel bottom 14c indicated by the central axis 18.

FIG. 9 shows another die pair 1 according to the present disclosure, comprising a female die 2 and a male die 3, in cross-section through an active region perpendicular to the direction of extension of the flow channels to be embossed.

FIG. 10 shows a detail C of this die pair 1. In this detail view, the free spaces X and the cambers Y are not drawn to scale and are exaggerated in height. In any case, the camber Y is smaller than the free space X (Y<X), so that sufficient space remains between the two dies 2 and 3 to receive displaced material of the first metal layer 11.

FIG. 11 shows, in an enlarged cross-section, another detail view of the die pair from FIG. 10. This detail view shows the camber Y, the free spaces X and the elevation U at one exemplary point for a camber Y.

FIGS. 1-11 are shown approximately to scale. FIGS. 1-11 show example configurations with relative positioning of the various components. If shown directly contacting each other, or directly coupled, then such elements may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in face-sharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. As yet another example, elements shown above/below one another, at opposite sides to one another, or to the left/right of one another may be referred to as such, relative to one another. Further, as shown in the figures, a topmost element or point of element may be referred to as a “top” of the component and a bottommost element or point of the element may be referred to as a “bottom” of the component, in at least one example. As used herein, top/bottom, upper/lower, above/below, may be relative to a vertical axis of the figures and used to describe positioning of elements of the figures relative to one another. As such, elements shown above other elements are positioned vertically above the other elements, in one example. As yet another example, shapes of the elements depicted within the figures may be referred to as having those shapes (e.g., such as being circular, straight, planar, curved, rounded, chamfered, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another, in at least one example. Further still, an element shown within another element or shown outside of another element may be referred as such, in one example.

It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. Moreover, unless explicitly stated to the contrary, the terms “first,” “second,” “third,” and the like are not intended to denote any order, position, quantity, or importance, but rather are used merely as labels to distinguish one element from another. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.

As used herein, the term “approximately” or “substantially” is construed to mean plus or minus five percent of the range unless otherwise specified.

The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.

Claims

1. A separator plate for an electrolyser, having a first metal layer,

the separator plate comprising:

an active region having at least one multitude of flow channels for a reaction medium, said flow channels being embossed into the first metal layer and having a channel bottom and channel walls arranged on both sides of the channel bottom, wherein webs are arranged between adjacent channel walls of adjacent flow channels,

wherein for one, some or all of the channel bottoms of the multitude of flow channels, the surface of the first metal layer opposite the channel bottom is at least partially substantially planar in a cross-section transverse to the direction of extension of the respective flow channel.

2. The separator plate according to claim 1, wherein, for one, some or all of the channel bottoms of the multitude of flow channels, the substantially planar region of the surface opposite the channel bottom has a width BE, determined transversely to the direction of extension of the respective flow channel, for which the following applies in relation to the original sheet thickness BA of the active region of the first metal layer before the active region is embossed into the first metal layer: 1.5 BA≤BE≤4 BA, preferably 2 BA≤BE and/or BE≤3 BA.

3. The separator plate according to claim 1, wherein a substantially planar region has a width BE, determined transversely to the direction of extension of the respective channel, over which the surface of the first metal layer opposite the channel bottom is at a substantially constant distance from a line connecting two points of the channel bottom that have the maximum depth of the channel, said line extending transversely to the direction of extension of the respective channel.

4. The separator plate according to claim 3, a substantially constant distance is given if, over the width BE, the surface opposite the channel bottom is at a distance AO from the straight line connecting the two points of maximum depth, wherein, over the width BE, the distance AO varies around the mean value of AO over the width BE by at most 0.5 AG, wherein AG is the maximum distance of the channel bottom from the straight line connecting the two points of maximum depth.

5. The separator plate according to claim 1, wherein the central axes of adjacent channels have a spacing AK of 7 BA≤AK≤13 BA.

6. The separator plate according to claim 1, wherein, for one, some or all of the channel bottoms of the multitude of flow channels, the channel bottom is at least partially convex, in particular over the width BE, in a cross-section transverse to the direction of extension of the respective flow channel.

7. The separator plate according to claim 1, wherein it is produced in a single-stage or multi-stage forming process.

8. The separator plate according to claim 1, wherein the first metal layer has a layer thickness BA, where 0.2≤BA≤0.8 mm.

9. The separator plate according to claim 1, wherein the first metal layer is made of or comprises stainless steel and/or titanium.

10. The separator plate according to claim 1, wherein the following applies at least in part for the mean spacing AK between adjacent flow channels of a multitude of flow channels embossed into the first metal layer for a reaction medium: 2 mm≤AK.

11. A die pair for producing a separator plate according to claim 1 by single-stage forming of the first metal layer using a male die and a female die as dies,

wherein for each of the surfaces of a flow channel of an active region that are substantially planar after forming, the structure that forms this surface of the active region of the separator plate a) on the die adjacent to this surface is at least partially cambered, in particular convex, in a cross-section perpendicular to the direction of extension of the respective flow channel of the active region, and b) on the other die has a free space, in particular a concave depression, in a cross-section perpendicular to the direction of extension of the respective flow channel.

12. The die pair according to claim 11, wherein one, some or all of the cambered structures have an elevation U beyond the regions of the die adjacent to the respective cambered structure in a cross-section perpendicular to the direction of extension of the respective flow channel of the active region, where 10 μm≤U≤150 μm.

13. The die pair according to claim 11, wherein one, some or all of the cambered structures have an elevation U beyond the regions of the die adjacent to the respective cambered structure in a cross-section perpendicular to the direction of extension of the respective flow channel of the active region, where U≥0.05 BA.

14. A method for producing a separator plate according to claim 1,

wherein,

in order to form the first metal layer, a metal sheet is arranged between a female die and a male die of a die pair and is formed by means of the die pair.