Electrochemical cell arrangement for an electrolyzer

Abstract

Electrochemical cell arrangement (12) for an electrolyzer, wherein the cell arrangement (12) comprises at least a portion of a first separator plate (10) and a second separator plate (10'), each with: • a first page and a second page facing away from it, • a flow field (14, 14') on each of the first and second sides, • several distribution areas (22, 22') with a plurality of channels (20'), wherein each pair of adjacent channels (20') is separated by a bridge (21'), and • a plurality of through-openings (16, 16') which are connected to the flow field (14, 14') of the first and second sides via one of the distribution areas (22, 22') in a fluid-conducting manner, wherein at least the following components are arranged between the first and second separator plate (10, 10'): • a membrane (28), • a first and second separation layer (26',26) which lie on different sides of the membrane (28); wherein at least one of the separating layers (26, 26') acts as an electrical insulator, at least the first separating layer (26') comprises a frame-shaped structurally rigid layer (40) which has a plastic layer (42) at least on one side, and wherein at least the first separating layer (26') has at least one section (50) which is supported on one of the distribution areas (22, 22') of at least one of the first and second separator plates (10, 10') and spans its channels (20').

Description

[0001] The invention relates to an electrochemical cell arrangement for an electrolyzer. A method for manufacturing an electrochemical cell arrangement is also disclosed.

[0002] Electrolyzers typically comprise a stack of electrochemical cell assemblies, each with multiple layers, including separator plates and a membrane. The stack of electrochemical cell assemblies may have two end plates that press the assemblies together, providing stability to the assembled stack. Furthermore, the electrochemical cell assemblies may include gas diffusion layers (GDL) and / or porous transport layers (PTL) positioned between the separator plate and the membrane.

[0003] The separator plate can fulfill several functions: indirect electrical contacting of electrodes of the membrane or a membrane electrode assembly (MEA), separation of media such as water, oxygen, or hydrogen, and electrical connection of adjacent electrochemical cell assemblies. The separator plate is also often referred to as a bipolar plate.

[0004] The separator plate typically includes several through-openings, sometimes also called ports. These serve as inlets or outlets for guiding a fluid through the separator plate. Furthermore, the separator plate typically includes a flow field and a distribution area for guiding the fluid between each through-opening and the flow field. The separator plate usually carries different media on its two surfaces, in particular, on one side a mixture of water and oxygen, and on the other side hydrogen. These media on the separator plate, or in the media chambers of the electrolyzer, typically exhibit a high pressure differential between themselves and between the media-carrying chambers, as well as an overpressure relative to the atmosphere.

[0005] Separator plates in electrolyzers are generally single-layered. Two-layer separator plates exist, for example, in which the flow field is designed as an additional metallic layer arranged on a metallic base plate to form the separator plate. The separator plates disclosed here are not limited to any of the described variants.

[0006] In addition to the aforementioned components such as separator plates, MEA, GDL, or PTL, further components can be incorporated within a cell arrangement. For example, cell frames and / or cell seals can be positioned between adjacent separator plates to fluidically seal the cells or the media from one another.

[0007] It is also known to use so-called insulating layers, which are typically made of a plastic and serve to electrically insulate components and / or adjacent cell assemblies from each other. In some cases, these insulating layers can also provide a sealing effect and thus replace conventional cell frames.

[0008] However, it was found that with the existing systems, especially with the existing sealing solutions, the sealing of the system is not always sufficient.

[0009] There is therefore a need to improve the reliability of the sealing of electrolyzers. The present invention provides a solution to this problem.

[0010] The present invention is defined by the subject matter of the independent claim and also by the method disclosed but not claimed below. Further developments are specified in the dependent claims, the following description, and the figures.

[0011] According to the invention, the, in particular insufficient, interaction of previous insulation layers and adjacent components of an electrolyzer was identified as a cause of the sealing problems observed so far.

[0012] For example, it has been found that conventional cell frames and insulation layers often exhibit comparatively low stiffness. Additionally, they are often inadequately or unfavorably supported at the edge of the flow field. As a result of compression and / or pressurization of the cell stack, these components can therefore be subjected to excessive local stress and, at least in sections, receive insufficient support. Consequently, they can be adversely deformed or damaged. This can also affect other components, such as an adjacent membrane or seal, which no longer receive the intended structural support. As a result, these adjacent components can buckle or tear, and / or the contact and thus mutual support can be interrupted, at least locally.This can also result in leakage problems or general reliability problems.

[0013] Accordingly, an electrochemical cell arrangement with a separation layer of increased stiffness is proposed here, which can reliably fulfill its function, particularly with regard to supporting an adjacent membrane, even in the case of non-continuous planar structural support.

[0014] More precisely, an electrochemical cell arrangement for an electrolyzer is disclosed, wherein the cell arrangement comprises a first separator plate and a second separator plate, each comprising at least a portion of the separator plate: • a first page and a second page facing away from it, • a flow field on each of the first and second sides, • several distribution areas with a large number of channels, where each pair of adjacent channels is separated by a bridge, and • a plurality of through-openings, each of which is fluid-conductingly connected to the flow field of the first and second side via one of the distribution areas, wherein at least the following components are arranged between the first and second separator plates: • a membrane, • a first and second separation layer that lie on different sides of the membrane, such that, for example, the first separation layer lies on a first side of the membrane and the second separation layer lies on a second side of the membrane, with the first and second sides of the membrane facing away from each other; where at least one of the separating layers acts as an electrical insulator, for example because it comprises the plastic layer below, wherein at least the first separating layer comprises a frame-shaped structurally rigid layer which has a plastic layer on at least one side, and wherein at least the first separating layer has at least one section which is supported on, and in particular abuts, one of the distribution areas of at least one of the first and second separator plates, and spans its channels.

[0015] The statement that a cell arrangement partially comprises a separator plate can be understood, in the case of a single-layer separator plate, to mean that at least one of the first and second sides of the separator plate can be assigned to a given cell arrangement. The corresponding other side can be assigned to a correspondingly adjacent cell arrangement. In the case of a two-layer separator plate, a corresponding single layer of the separator plate, which has one of the first and second sides of the two-layer separator plate, can be considered as a portion of the separator plate in a given cell arrangement. The corresponding further layer, which has the corresponding other side of the two-layer separator plate, can be assigned to an adjacent cell arrangement.

[0016] The flow field can encompass an electrochemically active region of the cell arrangements and / or form an electrochemically active region of a respective separator plate. For example, the electrochemically active region of a respective separator plate, and thus its flow field, can be obtained by an orthogonal projection of the membrane, in particular of its actual membrane surface and not, for example, of any reinforcing edges, onto the sides of the separator plates facing the cell interior. The flow field is accordingly located in this region of a separator plate obtained by the orthogonal projection. It is preferably configured to guide reaction fluids through this region by means of a channel structure of the flow field.

[0017] The distribution areas can serve to connect the flow field to at least one of the through-openings in a fluid-conducting manner. The channels and webs of the distribution areas can transition into channels and webs of the flow field and / or branch onto them and / or transfer fluid to or receive fluid from them.

[0018] The through-holes can be aligned with through-holes of adjacent cell arrangements in a manner known per se, in order to form fluid channels for guiding reaction media in a stack of several cell arrangements. Accordingly, the through-holes can serve as inlets or outlets for guiding a fluid through the separator plate. The through-holes can also be referred to as ports.

[0019] The membrane can, in particular, be encompassed by or form a membrane electrode assembly of a known design. It can, in particular, be configured as a proton exchange membrane (PEM).

[0020] The separating layers can be planar and / or layered components. They can have a constant thickness, at least in the uninstalled and / or unloaded state, with the exception of any burrs described below. In contrast to homogeneous plastic insulation layers of the prior art, the separating layers disclosed herein can, according to the embodiments described below, be composed of multiple parts and / or comprise inhomogeneous materials.

[0021] Furthermore, in deviation from the prior art, embodiments provide that an electrically insulating function is combined with increased structural stiffness in a single separating layer. A structurally stiff layer, as comprised of at least one separating layer, can be understood to be dimensionally stable under its own weight and / or under mechanical clamping pressures and / or under electrochemical operating pressures. In particular, the structurally stiff layer can only be deformed elastically and not plastically in such situations.

[0022] According to one variant, the structural stiffness of the separating layers includes the fact that they have a modulus of elasticity of more than 60000 MPa (megapascals).

[0023] The frame-like shape of the separation layers can include each having a recess and surrounding it. In particular, each separation layer can have, for example, a central recess with a closed perimeter and define this perimeter. Through this recess, a region of the membrane can be exposed and accessible to reaction media.

[0024] Preferably, the side on which the first separating layer has a plastic layer is the side of its side that is in contact with the membrane.

[0025] According to one embodiment, the material of the plastic layer differs from the remaining material of an associated separating layer, with the exception of an optional additional plastic layer on the side of this separating layer facing away from the membrane. The remaining material of the associated separating layer can, in particular, be homogeneous. It can be a stiffer material than that of the plastic layer, for example, a stiffer plastic. However, according to embodiments described below, it can, in particular, be a metallic material.

[0026] The increased structural stiffness of at least the first or both separation layers reduces the risks associated with prior art regarding unfavorable deformations, insufficient support, and / or damage. In particular, by having a structurally stiff separation layer span the channels of an opposing distribution area, the reduced structural support of the separation layer by these channels can be at least partially compensated for. Furthermore, the plastic layer provides reliable electrical insulation.

[0027] Thus, the separating layers can enable reliable and, in particular, securely sealed operation of an electrolyzer in relation to existing insulation layers and / or existing cell frames.

[0028] According to a further development, the structurally rigid layer surrounds a recess in a frame-like manner. This can be, in particular, a central recess and / or a recess that exposes the membrane, at least in part, as previously described. The structurally rigid layer can have a ridge adjacent to the recess, at least in some sections. This ridge can accordingly form an edge or boundary of the recess or be encompassed by it.

[0029] According to one embodiment, the structurally rigid layer is oriented such that the ridge faces away from the membrane. For example, the ridge can project from the structurally rigid layer in only one direction. No comparable ridge can project in the other direction; that is, this side of the structurally rigid layer can be essentially flat or at least flatter than the side with the ridge. In summary, only a single, one-sided ridge can be present adjacent to the recess, and this ridge can project in only one direction. The direction in which the ridge projects can, in particular, be orthogonal to a plane of the structurally rigid layer and / or a plane of the recess and / or to its opening cross-section.

[0030] Because the ridge is turned away from the membrane, the risk of damage to the membrane can be reduced, especially when the media-carrying spaces of the cell arrangement are pressurized.

[0031] According to further training, the structurally rigid layer comprises metal, and in particular a metal sheet. This sheet can be coated with the plastic layer on at least one side. The burr can accordingly be a metal burr. The burr can also be at least partially coated with plastic, for example, because a recess adjacent to the burr is punched out of the coated metal sheet only after the plastic layer has been applied, thus creating the burr.

[0032] According to one variant, the structurally rigid layer and / or a respective separating layer as such is formed entirely by a metal material and in particular a metal sheet, with the exception of at least one plastic coating.

[0033] The use of metal, and in particular a metal sheet, is a cost-effective, easy-to-manufacture and reliable way to achieve increased structural stiffness of the separating layers.

[0034] In general, the structurally rigid layer can be congruent with the plastic layer. The optional metal of the structurally rigid layer can extend within or even constitute the entire surface of the structurally rigid layer. Consequently, the metal can also span the channels of the distribution area and / or extend across the entire surface from the frame-like recess to an outermost edge of the structurally rigid layer. Therefore, the metal cannot simply form a locally reinforcing structure, which, for example, is only partially embedded in another optional material of the structurally rigid layer. Instead, the metal or metal sheet can form the structurally rigid layer itself and / or in its entirety and / or span the entire surface of the structurally rigid layer.

[0035] According to further training, at least the first separation layer and / or the membrane, or possibly only a peripheral area of ​​the membrane, completely covers the distribution area whose channels are spanned. This can be the case, for example, when considering an orthogonal projection along a stacking axis, where the separation layer, membrane, and distribution area are projected onto a common plane. In this way, any lack of structural support for the separation layer in the area of ​​the channels can be at least partially compensated for.

[0036] According to further training, the plastic layer comprises a polyester, in particular polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polyimide (PI), or a polyetheretherketone (PEEK). These materials enable reliable electrical insulation with a process-safe, layer-by-layer application and a low layer thickness.

[0037] According to a further development, the plastic layer comprises a plastic film laminated onto the structurally rigid layer. For example, the plastic film is bonded to the structurally rigid layer by means of an adhesive, in particular an acrylic adhesive. This simplifies the production of the release layers disclosed here and allows, for example, the punching out of the frame-shaped circumferential recess from a release layer in its already laminated state.

[0038] According to a further development, at least the first separation layer also has a plastic layer, at least partially, on a side facing away from the membrane. This additional plastic layer can be designed analogously to the plastic layer on the side of the separation layer that contacts the membrane. This allows the rigid layer material to be additionally electrically insulated and / or protected from contact with reaction media. This can reduce the requirements for the mechanical and / or chemical resistance of the rigid layer material.

[0039] According to one embodiment, the structurally rigid layer is made of stainless steel or a titanium alloy, each of which can in turn be formed as a metal sheet. Stainless steel is characterized by high mechanical strength at a lower cost than titanium, whereas titanium offers higher corrosion resistance with low weight and at least sufficient mechanical strength.

[0040] According to a further embodiment, at least the first separating layer is topography-free. This can be understood as a substantially flat and / or planar design of the separating layer. In particular, the topography-free nature can exist at least in the uninstalled state. However, due to elastic deformations in the installed state, non-planar deformations of the separating layer can occur, at least in some areas. In particular, the topography-free nature can include the absence of any intentional and / or manufacturing-related embossing or other intentional and / or manufacturing-related structuring on the outer surfaces of the separating layer. An exception can be a burr, as described below, and in particular a metal burr.

[0041] According to further training, the structurally stiff layer is at least twice as thick or at least three times as thick as the plastic layer, i.e., the plastic layer applied to at least one of its surfaces. This deliberately increases the proportion of the material or layer that primarily contributes to structural stiffness compared to the plastic layer.

[0042] A general insight of the invention is that a comparatively thin plastic layer is sufficient to achieve electrical insulation. The resulting freed-up space within the electrochemical cell arrangement can thus be occupied by a structurally rigid layer of a corresponding thickness. This results in an overall increase in stiffness along with the associated advantages.

[0043] According to further training, the plastic layer has a thickness of less than 0.3 mm, and in particular less than 0.1 mm, and furthermore, in particular less than 0.05 mm. It has been shown that reliable electrical insulation can be achieved even with such small thicknesses. As previously described, reducing the thickness of the plastic layer allows for an increase in the thickness of the structurally rigid layer without increasing the overall height of the separating layer and / or the cell arrangement.

[0044] Another embodiment provides that the separator plate closest to the first separation layer has a seal on its side facing the first separation layer which rests against the first separation layer, and / or wherein the separator plate closest to the second separation layer has a seal on its side facing the second separation layer which rests against the second separation layer.

[0045] The seal can, for example, serve to fluidically seal the electrochemical cell arrangement against an adjacent through-opening and / or against the outside environment. The increased structural stiffness of the separation layers disclosed here can generally improve the reliability of contact with the seal and thus the overall fluidic seal.

[0046] The invention also relates in principle to an electrochemical system comprising a plurality of cell arrangements according to any of the aspects disclosed herein, in particular in a stacked arrangement.

[0047] Furthermore, a method for producing an electrochemical cell arrangement according to any variant disclosed herein is disclosed as a principal claimable part of the invention. Variants and further developments described in the context of the cell arrangement may also apply to the method, in particular to its identical features.

[0048] In particular, the cell arrangement can comprise at least a portion of a first separator plate and a second separator plate, each with: • a first page and a second page facing away from it, • a flow field on each of the first and second sides, • several distribution areas with a multitude of channels, where each pair of adjacent channels is separated by a bridge, and • a plurality of through-openings, each of which is fluid-conductingly connected to the flow field of the first and second side via one of the distribution areas.

[0049] The procedure may include, in particular, the following: • Arranging, between the first and second separator plates, a membrane and a first and second separation layer, which abut on different sides of the membrane; wherein at least the first separation layer comprises a frame-shaped structurally rigid layer which has a plastic layer at least on one side, and wherein at least the first separation layer has at least one section which is supported on a first of the distribution areas of at least one of the first and second separator plates and spans its channels.

[0050] According to a further development of the process, the plastic layer of the first separation layer is in contact with the membrane.

[0051] According to a further development, the method for producing the frame-shaped, structurally rigid layer further comprises: punching out or otherwise separating a section from a structurally rigid material layer with a plastic coating, so that a frame-shaped circumferential recess is created. In this context, a burr can be formed according to any variant disclosed herein, in particular as a result of the punching.

[0052] Accordingly, the arrangement can further include: arranging the structurally rigid layer in such a way that a burr produced during its manufacture faces away from the membrane.

[0053] Exemplary embodiments of the invention are shown in the accompanying figures and are explained in more detail below. The same reference numerals can be used across figures for identical or comparable features. Within a figure, only selected instances of a feature may be provided with a reference numeral that is generally assigned to that feature. The figures show: Fig. 1 a first side of a separator plate, such as can be used in a cell arrangement according to the invention; Fig. 2 a second side of the separator plate Fig. 1; Fig. 3 a cell arrangement according to an embodiment of the invention in an exploded view; Fig. 4 the cell arrangement from Fig. 3 in the compound state; Fig. 5 a perspective partial section view of the cell arrangement from Fig. 4; Fig. 6 a detailed view of a separation layer of the cell arrangement from the Fig. 3-5; Fig. 7 a side view of a section of Fig. 5.

[0054] Fig. Figure 1 shows a first side of an exemplary separator plate 10, as it can be used in a cell arrangement 12 according to the invention, see Fig. 3. The side shown corresponds to an anode side. Fig. Figure 2 shows the second side of the example separator plate 10. Fig. 1. This side corresponds to a cathode side.

[0055] The following will refer to the Fig. 1 and Fig. Two selected features of the separator plate 10 are explained. The exemplary separator plate 10 has a non-restrictive rectangular shape. It comprises a single metallic layer, which consists, for example, at least predominantly or entirely of titanium or stainless steel or alloys thereof. The metallic layer 10 can, for example, have a thickness of at least 0.1 mm, in particular at least 0.25 mm, and / or at most 0.8 mm, in particular at most 0.5 mm.

[0056] The following refers to Fig. Figure 1 shows that the separator plate 10 has a flow field 14 on its first side, as depicted therein. This field is designed to distribute water supplied from first through-openings 16 near a first side of the flow field 14 over a surface and to direct it in the flow direction to first through-openings 16 near an opposite second side of the flow field 14. Fig. The flow direction runs from the upper left to the lower right or vice versa. The flow field 14 is fluid-conductingly connected to the first through-openings 16 via a distribution area 22 on the first and opposite sides of the flow field 14 as described.

[0057] A channel structure 18 is provided in the flow field 14. The individual channels or depressions 20 of the channel structure 18 are separated from each other by ribs or elevations 21, see the following explanation. Fig. 5. The flow field 14 forms an electrochemically active area (active area) of the corresponding side of the separator plate 10. The distribution areas 22 lie outside this electrochemically active area.

[0058] The distribution areas 22 also each comprise a channel structure 18'. The individual channels / recesses 20' of the channel structure 18' are separated from each other by webs / raised sections 21', see Fig. 5. The flow field 14 is optionally separated from each adjacent distribution area 22 by a transition area 24. This transition area is lowered relative to the crests of the flow field 14 and the distribution area 22, see figure. Fig. 5.

[0059] The separator plate 10 also includes second through-openings 16'. These are again arranged on or near opposite sides of the flow field 14, but on different sides than the first through-openings 16. More precisely, they are located in Fig. 1. Optionally, several first through-openings 16 are arranged near and / or opposite an upper and lower side of the flow field 14 (or generally a first and second side), and optionally, several second through-openings 16' are arranged near and / or opposite a left and right side of the flow field 14 (or generally a third and fourth side). Due to the lack of a distribution area 22, the second through-openings 16' are not fluid-conductingly connected to the flow field 14 on the separator plate side shown. Rather, the second through-openings 16' are located on the side of the separator plate 10 facing the viewer. Fig. 1 sealed off from the flow field 14.

[0060] In Fig. Figure 2 shows that such a fluid-conducting connection is made on the second side of the separator plate 10 via distribution areas 22'. These distribution areas 22' are generally analogous to the distribution areas 22 on the first side. Fig. 1 formed and connect the second through-openings 16' with the flow field 14' on this second side.

[0061] However, the distribution areas 22 of the first side are not also present on the second side. On this second side, the first through-openings 16 to the flow field 14' are sealed. Thus, the first through-openings 16 are not fluid-conductingly connected to the flow field 14' of the second side.

[0062] The flow field 14' of the second side has a channel structure 18" that is complementary to the flow field 14 of the first side. Despite the channels and webs being oriented orthogonally to the flow direction between the through-openings 16', the flow field 14' can be crossed with minimal resistance by the hydrogen carried on this side, in a manner known per se, i.e., also by flow through the GDL (not shown here). Consequently, the second through-openings 16' are designed for the discharge of hydrogen.

[0063] Fig. Figure 3 shows an exploded view of an electrochemical cell arrangement 12 according to an exemplary embodiment of the invention. The cell arrangement 12 is part of an electrochemical system in the form of an electrolyzer. Electrolyzers typically comprise a plurality of such cell arrangements 12 stacked on top of each other. A stacking axis S, along which the individual components of the cell arrangement 12 are stacked on top of each other and, in particular, compressed together, is shown. Along this stacking axis S, further cell arrangements 12 of an electrolyzer, not shown, are also stacked on top of each other and compressed together with the cell arrangement 12 shown.

[0064] The cell arrangement 12 comprises two separator plates 10, 10', as shown by the Fig. 1 and Fig. 2 explained. These are arranged such that one of the separator plates 10, 10' faces the interior of the cell arrangements 12 and / or the corresponding other separator plate 10, 10' with its first side and the other with its second side. The outward-facing sides of the separator plates 10, 10' cannot be considered an actual part of the cell arrangement 12. They can, for example, be assigned to and / or delimit adjacent cell arrangements 12 not shown.

[0065] In the case of Fig. 3 shows the second side of the upper separator plate 10 according to Fig. 2 as part of the cell arrangement 12 inwards. In the lower separator plate 10', the first side faces according to Fig. 1 as part of the cell arrangement 12 inwards.

[0066] A separating layer 26, 26' is located on each inwardly facing side of each separator plate 10, 10' that forms part of the cell arrangements 12. The separating layers 26 each have a central recess 27, which they surround in a frame-like manner. Apart from any deformations during installation, the separating layers 26, 26' are flat and topography-free components that extend parallel to the separator plate 10, 10'.

[0067] A membrane 28 with media diffusion structures 30 adjoining it on both sides is arranged between the separation layers 26, 26'. The latter comprise, for example, a GDL and / or a PTL. The membrane 28 has a membrane surface 29 at least opposite the recesses 27 of the separation layers 26, 26', e.g., comprising a proton exchange membrane (PEM) made of polymer material. A circumferential reinforcing rim 31 runs along the outer edges of the membrane surface 29.

[0068] An orthogonal projection of the membrane surface 29 along the stacking axis S onto the separator plates 10, 10' defines their electrochemically active areas and respective flow fields 14, 14'.

[0069] Finally, it should be noted that the separating layers 26, 26' and also the membrane 28 include fluid feedthroughs 32, which are connected to the ones based on the Fig. 1 and Fig. The two described through-openings 16, 16' are aligned. Selected of these fluid passages 32 are marked with a corresponding reference numeral as examples for the uppermost separation layer 26. Also shown are recesses 34 provided within the separation layers 26, 26', the separator plate 10, 10' and the membrane 28 for the passage of fastening elements not shown separately. Selected of these recesses 34 are located in the lower part of Fig. 3 marked with a corresponding reference mark.

[0070] Fig. Figure 4 shows the cell arrangement of 12. Fig. 3 in the assembled and, in particular, the compressed state. Additional adjacent cell arrangements 12 are shown, forming an exemplary stack of three cell arrangements 12. It can be seen that the separating layers 26, 26', separator plates 10, 10' and the membrane 28, which are not marked separately here, are arranged essentially congruently with each other within a respective cell arrangement 12.

[0071] Furthermore, in Fig. 4 marks the location of a section plane AA. The resulting partial section view is shown in Fig. 5 shown. Based on Fig. Section 5 below explains in more detail the structure of the uppermost cell arrangement 12 and, in particular, the separation layers 26, 26'. A particularly relevant area for this is... Fig. 5 is framed by a dotted line; this is described in detail in Fig. 7. The designation of the separator plates 10, 10' with the corresponding reference symbols refers to the orientations from Fig. 3 Reference.

[0072] It becomes clear that the massive areas of the separation layers 26, 26' are positioned outside the flow fields 14, 14'. Instead, the recesses 27 are located there, or rather opposite the flow fields 14, 14'.

[0073] In the illustrated example, the uppermost separating layer 26, and more precisely a solid portion thereof, is located opposite, among other things, a region of the uppermost separator plate 10 that faces away from the distribution area 22 or is formed on its inner side. This region of the separator plate 10 is designed to be complementary to the distribution area 22. An elastomeric seal 36 is arranged in this region and rests against the opposite outer side of the separating layer 26. This elastomeric seal 36 includes, by way of example, two sealing lips 38 projecting towards the insulation layer 42. The upper separating layer 26 rests against the membrane 28 with its side facing away from the elastomeric seal 36.

[0074] Also shown is the lower separation layer 26', which rests against the side of the membrane 28 facing away from the upper separation layer 26. With its correspondingly opposite side, the lower separation layer 26' rests against the distribution area 22 of the nearest and in Fig. 5 lower separator plate 10' of the uppermost electrochemical cell arrangements 12. In this respect, a section 50 of the separating layer 26' spans, or in other words covers, the channels 20' of this distribution area 22 along their entire length L. The latter is shown as an example for the lowest separator plate 10'.

[0075] The channels 20' form areas of lack of structural support for the separation layer 26' by the adjacent separator plate 10'. As shown below by Fig. As explained in section 6, this lack of structural support can, however, be at least partially compensated by the separating layers 26, 26' formed according to the invention.

[0076] Based on Fig. Section 6 illustrates the structure of the separating layers 26, 26' by way of example. Fig. Figure 6 is a partial sectional view, with the section plane perpendicular to the plane of the separating layers 26, 26' shown. The sectioned portion includes an edge region adjacent to the recess 27 of the separating layers 26, 26'. The separating layers 26, 26' are shown to be identical in the described embodiment for illustrative purposes only. This is not mandatory.

[0077] The separating layers 26, 26' each comprise a structurally rigid layer 40 made of metal, such as titanium or stainless steel, and more precisely, of a metal sheet. This sheet is coated on both sides with a plastic layer 42, which in the example shown comprises PEN. The plastic layers 42 completely cover the respective outer surfaces of the layer 40, thus electrically isolating them from the environment. Furthermore, the plastic layers 42 provide protection against mechanical and chemical damage to the layer 40.

[0078] One in Fig. The vertical thickness dimension of layer 40 significantly exceeds the respective thickness of the plastic layers 42 and is at least four times greater in the example shown. Thus, the structurally stiffer component of the separating layers 26, 26', in the form of layer 40, deliberately occupies a larger proportion of the volume and, in particular, the thickness of the separating layers 26, 26'. Consequently, these layers are mechanically stiffened in a targeted manner. Conversely, it was found that the thickness of the plastic layers 42 can be significantly reduced in comparison without impairing their electrically insulating properties.

[0079] In the example shown, the metal sheet is received in a state already coated on both sides and is further processed, for example as sheet or strip material. Individual separating layers 26, 26', including their recesses 27, are punched out of this sheet. As a result, a metal burr 44 forms on one side at the inner edge defining the recess 27, or, in other words, at the inner edge of the recess 27. On the opposite side of the separating layers 26, 26', however, no comparable metal burr 44 is present (see figure). Fig. 6.

[0080] As in Fig. As shown in Figure 7, the separating layers 26, 26' are oriented such that their metal ridge 44 faces away from the membrane 28 held between them. This is illustrated by the areas outlined with dashed lines in Figure 7. Fig. 7. In this way, damage to the membrane 28 by the metal burr 44 is avoided.

Claims

[1] Electrochemical cell arrangement (12) for an electrolyzer, wherein the cell arrangement (12) comprises at least a portion of a first separator plate (10) and a second separator plate (10'), each with: • a first page and a second page facing away from it, • a flow field (14, 14') on each of the first and second sides, • several distribution areas (22, 22') with a plurality of channels (20'), wherein each pair of adjacent channels (20') is separated by a bridge (21'), and • a plurality of through-openings (16, 16') which are connected to the flow field (14, 14') of the first and second sides via one of the distribution areas (22, 22') in a fluid-conducting manner, wherein at least the following components are arranged between the first and second separator plate (10, 10'): • a membrane (28), • a first and second separation layer (26',26) which lie on different sides of the membrane (28); wherein at least one of the separating layers (26, 26') acts as an electrical insulator, at least the first separating layer (26') comprises a frame-shaped structurally rigid layer (40) which has a plastic layer (42) at least on one side, and wherein at least the first separating layer (26') has at least one section (50) which is supported on one of the distribution areas (22, 22') of at least one of the first and second separator plates (10, 10') and spans its channels (20'). [2] Electrochemical cell arrangement (12) according to claim 1, wherein the structurally rigid layer (40) surrounds a recess (27) in a frame-like manner and furthermore has at least sectionally a ridge (44) adjacent to the recess (27), wherein the structurally rigid layer (40) is oriented such that the ridge (44) faces away from the membrane (28). [3] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein the structurally rigid layer (40) comprises metal and in particular a metal sheet, wherein the burr (44) is in particular a metal burr. [4] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein at least the first separation layer (26') and / or the membrane (28) completely covers the distribution area (22) whose channels (20') are spanned. [5] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein the plastic layer (42) comprises a polyester, in particular polyethylene terephthalate, PET; polyethylene naphthalate, PEN; a polyimide, PI; or a polyetheretherketone, PEEK. [6] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein the plastic layer (42) comprises a plastic film laminated onto the structurally rigid layer (40). [7] Electrochemical cell arrangement (12) according to the preceding claim, wherein the plastic film is bonded to the structurally rigid layer by means of an adhesive, in particular by means of an acrylic adhesive. [8] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein at least the first separation layer (26') also has a plastic layer (42) at least partially on a side facing away from the membrane (28). [9] Electrochemical cell arrangement (12) according to claim 8, wherein the structurally rigid layer (40) is made of stainless steel or a titanium alloy. [10] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein at least the first separation layer (26') is topography-free. [11] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein the structurally rigid layer (40) is at least twice as thick as the plastic layer (42) on one of its surfaces. [12] Electrochemical cell arrangement (12) according to one of the preceding claims, wherein the plastic layer (42) has a thickness of less than 0.3 mm and in particular less than 0.1 mm and further in particular less than 0.05 mm. [13] Electrochemical cell arrangement (12) according to any one of the preceding claims, wherein the separator plate (10, 10') closest to the first separating layer (26') has a seal (36) on its side facing the first separating layer (26') which rests against the first separating layer (26') and / or wherein the separator plate (10, 10') closest to the second separating layer (26) has a seal (36) on its side facing the second separating layer (26) which rests against the second separating layer (26).

Images