Separator for electrochemical system and electrochemical system

Abstract

The invention relates to a separator for an electrolyser or another electrochemical system. The invention also relates to an electrochemical system.

Description

Technical Field

[0001] The present invention relates to a separator for an electrolyzer or another electrochemical system. The present invention also relates to an electrochemical system. Background Art

[0002] Electrochemical systems typically include stacked separators and elements arranged therebetween, such as membrane electrode assemblies (MEAs). The separators include through openings, each of which is fluid-conductively connected to a fluid channel of the electrochemical system and / or defines a section of the channel. The through openings or fluid channels can, for example, supply fuel (such as hydrogen or methanol), reaction gas (such as air or oxygen), or a cooling medium to the electrochemical system and / or remove reaction products and heated cooling medium from the system. In the case of an electrolyzer, water can be added and oxygen and hydrogen can be removed.

[0003] In each case, the supplied fluid should generally only leave or enter the through openings on one side of the separator, in particular so as to flow along the corresponding side of the separator. On the corresponding different sides of the separator, such leaving or entering should be prevented. For this purpose, seals are used, which, for example, extend in the form of a ring in particular around the through openings carrying such fluid.

[0004] Generally, it is provided that on one side of the separator (or a bipolar plate including a plurality of separators), a first fluid can leave or enter an associated through opening, and on the corresponding other side, another second fluid can leave or enter an associated through opening.

[0005] An established type of seal involves seals that are elastically deformable during assembly and in particular during clamping or squeezing, or also when the electrochemical system is closed, and that are made of a non-metallic material, in particular an elastomeric seal. Such a seal can, for example, be directly molded onto the corresponding side of the separator.

[0006] It has been shown that with previous solutions, the desired sealing effect is not always reliable enough. Summary of the Invention

[0007] The present application thus aims at the following task: improving the fluid sealing of the separators of an electrochemical system and in particular the fluid sealing of their through openings.

[0008] This object is solved by the subject matter of the independent claims. Advantageous further embodiments are given in the dependent claims, the description, and the drawings.

[0009] Therefore, a separator for an electrolyzer or other electrochemical system is proposed, which has a plate member, and the plate member includes:

[0010] · A first side and a second side facing away from the first side,

[0011] · A flow field on each of the first side and the second side,

[0012] · A plurality of distribution regions, the distribution regions having a plurality of channels, wherein each two adjacent channels are separated by webs, and

[0013] · A plurality of through openings,

[0014] wherein the through openings are each fluid-conductively connected to the flow field on one of the first side and the second side via one of the distribution regions, and are each fluid-sealed from the flow field on the corresponding other side of the first side and the second side by a seal of the separator,

[0015] wherein at least one of the seals extends at least in some sections along the edge region of the through opening sealed by the seal and has at least one outer surface, which is at least in some sections topographical along the longitudinal extension and / or has a varying height profile, at least in the uninstalled state of the electrochemical system.

[0016] The seal can be made of, or become formed by, an elastomeric profile molded, inserted, adhered, knotted or applied to the separator.

[0017] According to the present invention, it is recognized that the previous lack of sealing effect may be due to, for example, the fact that the seals are unevenly compressed along their course. The separator typically has large distribution regions with channels, and the seals of adjacent separators are at least indirectly supported on the channels. For example, additional components, in particular elastically deformable cell frames or MEAs, can be arranged between the separators, and the seals can be indirectly supported on the adjacent separators via these components.

[0018] If the seal of the first separator is supported on such a channel-type distribution region of an adjacent second separator and / or on a channel-type distribution region of the separator to which the seal is attached and, for example, injection-molded, the seal may be irregularly loaded and thus irregularly deformed. This may impair the sealing effect. Such a type of support is particularly likely to occur due to the compression of the electrochemical system during assembly.

[0019] Instead, it is proposed that the seal is formed relief-shaped at least in some sections, and in particular has a varying height profile, while the seal in the prior art typically has a completely flat outer surface. This can at least partially compensate, for example, for the non-uniformities of the channels and webs in the distribution area of the adjacent separator plates on which the seal is at least indirectly supported.

[0020] In particular, the relief-shaped configuration can exist at least in sections of the seal that extend along the non-uniform sections of the separator plate, such as the distribution area with channels and webs and / or sections of the seal that are opposite or face the non-uniform sections of the adjacent separator plate. Preferably, the type of relief-shaped configuration disclosed herein exists in most or all such sections of the seal.

[0021] The separator plates disclosed herein can be single-layer separator plates, the plate components of which are formed, for example, from a single-section material, in particular a sheet. However, the separator plates can also each have two separate plates (i.e., two separate plate components) that are firmly connected to each other, such as two separate plates welded together. The separator plates are used, for example, for electrically contacting the electrodes of individual electrochemical cell monomers (such as fuel cell monomers) and / or for electrically connecting adjacent cell monomers (series connection of cell monomers). In particular, in these cases, they are also referred to as bipolar plates. The separator plates can also be used to dissipate the heat generated in the cell monomers between the separator plates. For example, such waste heat may be generated when converting electrical energy or chemical energy in a fuel cell.

[0022] As described, the electrochemical system can be an electrolyzer, but in particular can also be a fuel cell monomer system, an electrochemical compressor, or a redox flow battery.

[0023] The channels and webs in the distribution area can be surrounded by and / or partially form a medium guiding structure, and can be configured to supply one or more fluids or media to the active area of each separator plate and / or individual plate, and / or to convey the fluid or medium away. In particular, the channels can guide the fluid and can be bounded by the webs. The active area of the separator plate and / or individual plate can enclose or define an electrochemical cell monomer. In a fuel cell monomer, the reaction media, i.e., the fuel and the reaction gas, are typically guided on opposite sides of the separator plate, while the coolant is guided between the individual plates of the separator plate. In an electrolyzer, the reaction media are also guided on opposite sides of the separator plate, and there is no need to guide the coolant (if present in the electrolyzer) between any individual plates.

[0024] The through-opening can be configured according to aspects of the prior art discussed above. The through-openings of the partitions can be aligned with one another in the stacked partitions. Alternatively or additionally, they can be arranged to overlap one another at least in some sections. Alternatively or additionally, at least in some sections, the through-openings can jointly define and / or delimit a fluid passage.

[0025] The fluid connection of the through-opening to the flow field can include the possibility of a fluid line between these features without these features having to be structurally integrated and / or directly connected to one another.

[0026] The through-opening can be molded into the material of the partition and in particular its plate member or cut out of the material. Generally, at least one plate member can be a one-piece member, preferably formed of a homogeneous material, in particular a metallic material. However, in addition to this one-piece and homogeneously formed member made of one material, the plate member can have a coating. The partition can also be made of plastic.

[0027] Similar to the distribution area, the flow field can include channels and webs and / or be part of a medium guiding structure. Alternatively, the flow field can be without such a structure and in particular flat, in other words, smooth.

[0028] The channels and webs of the distribution area and / or the flow field can be formed into the plate member by, for example, hydroforming, coining, and / or deep drawing. In the context of the present disclosure, the term "coining" or "coin-type" can be understood to particularly refer to hydroforming, roll coining, stroke coining, and / or deep drawing.

[0029] The seal can have a position and / or an extent such that the fluid emerging from the through-opening sealed by it can enter at least a partial area of the distribution area assigned to this through-opening. In particular, this can be an area close to and / or directly adjacent to and / or incorporated into the through-opening. The seal can, for example, fluidically separate this partial area from another partial area of the distribution area and / or from the flow field. In particular, the seal can extend in and / or overlap and / or span at least in some sections an area of one of the distribution areas among the distribution areas. According to one variant, such a distribution area is positioned adjacent to or in direct abutment with the through-opening sealed by the seal.

[0030] The distribution area associated with the through-opening can be understood as, for example, a distribution area that is established and particularly positioned such that it receives, particularly directly, the fluid emerging from the through-opening, or introduces the fluid, particularly directly, into the through-opening. In particular, the associated distribution area can be directly adjacent to the through-opening or positioned at a certain distance from the through-opening, which distance can also be 0 cm, less than 5 cm, and particularly less than 2 cm. Alternatively or additionally, the divided distribution area can be the distribution area closest to the through-opening among a plurality of distribution areas.

[0031] The seal can consist of or be formed from an elastomer injected onto the separator in an injection molding process. The elastomer can be FKM (fluororubber), silicone rubber, or NBR rubber (acrylonitrile-butadiene rubber), PUR (polyurethane), NR (natural rubber), FFKM (perfluororubber), SBR (styrene-butadiene rubber), BR (butadiene rubber), FVMQ (fluorosilicone rubber), CSM (chlorosulfonated polyethylene), HNBR (hydrogenated acrylonitrile-butadiene rubber), ACM (acrylate rubber), AEM (acrylate-ethylene rubber), EPDM (ethylene propylene diene monomer rubber), IIR (butyl rubber), or a mixture of the above substances. However, the present invention is not limited to these materials. Alternatively, the elastomeric profile can also be produced using other processes.

[0032] The outer surface can be surrounded by at least one sealing lip of the seal. As will be explained below, the seal can have several sealing lips, each of which can have an outer surface and particularly an outer surface that is topographically shaped as disclosed herein. This is particularly evident when the separator is not installed or not compressed.

[0033] The outer surface can define such a surface of the seal that contacts an adjacent component over most or all of its surface area. The component can be, for example, the MEA or the cell frame as described below. The outer surface can be the only surface of the seal that allows such installation. If there are multiple outer surfaces, for example, due to the provision of several sealing lips, these outer surfaces can be the only surfaces of the seal that allow the seal to make the corresponding contact.

[0034] The seal can largely and particularly completely surround the associated through-opening (i.e., the through-opening sealed by the seal). Thus, it can also largely or completely surround the edge region of the through-opening. The extension of the seal along the edge region does not necessarily need to be at a constant distance from the edge region. For example, such a distance can be measured parallel to the plate plane. However, according to an embodiment, a corresponding constant distance can be provided. Additionally, the extension of the seal along the edge region does not need to be completely parallel to the edge region, however, such an extension can also be provided according to an embodiment.

[0035] In particular, the extension of the seal along the edge region can be understood to mean that the local extension direction of the seal has a vector component that extends parallel to the extension direction of the adjacent section of the edge region. This vector component can be, for example, greater than the vector component orthogonal to the extension direction of the adjacent section of the edge region.

[0036] Unless otherwise stated or obvious, the position of the partition mentioned herein can be synonymous with the mention of its (one or more) plate components, and in particular specifically synonymous with the mention of that plate component. As described above, the partition can optionally include a plurality of plate components of the type disclosed herein.

[0037] A topographical outer surface or a substantially topographical surface can be understood to mean that a surface topography is provided. In particular, this can be synonymous with an uneven and / or inconsistent flat shape of the surface.

[0038] In particular, the topographical outer surface can be understood to have a varying height profile. The height profile can extend along a height axis. This can extend orthogonally to the longitudinal extension of the seal and / or the plate plane of the partition. The varying height profile can include a varying height, or in other words, a varying position of the outer surface relative to this height axis, which is particularly present when observed along the longitudinal extension of the seal. In other words, seal sections with different and thus varying heights can follow one another along this longitudinal extension. The varying section does not always have to achieve the same deflection relative to the height axis.

[0039] In a manner known per se, the flat surface plane of the partition can be defined, for example, by the edges of the partition and / or its plate components, or by the flat regions of the partition and / or its plate components that are not deformed by embossing or deep drawing processes to form the medium guiding structures described herein and in particular the distribution regions, or do not form other embossed or deep drawn structural features. On the one hand, the flat surface plane can extend in the neutral fiber of the corresponding section of the partition and / or its plate components; on the other hand, it can also be considered to take the surface of the associated section of the plate as the flat surface plane. However, when using the latter method, if applicable, it must be ensured that only the material thickness of one of the two individual plates considered takes into account the distance or similar factors.

[0040] The state of a separator installed in an electrochemical system may include that it has been mechanically compressed. In the manner described below, the electrochemical system may include a plurality of separators, in particular separators stacked on top of each other, which are mechanically compressed in a manner known per se. Due to this compression, the seal can be elastically deformed and the topographic configuration of the outer surface of the seal can be compressed accordingly. In particular, any varying height profile of the seal can be adjusted to a flatter height at least in some sections and / or at least partially. However, this is advantageous for achieving a reliable sealing effect, and the topographic outer surface disclosed herein can particularly facilitate the realization of such a flat height in the installed state and in particular in a compressed state.

[0041] According to one embodiment, the outer surface shape is designed to be similar to such an area of ​​the corresponding side of the first side and the second side: the seal is arranged on this area and the outer surface extends along this area. This is particularly applicable to the height profile and / or surface shape and / or surface topography of the outer surface and this area. For example, the outer surface can be corrugated, curved or roughly contoured in the same way as the above-mentioned area. The similarity can particularly refer to the overall shape of the outer surface and the corresponding area, such as about corrugations, rectangles or sawtooth shapes, or roughly the alternating sequence of similar shapes and / or surface features. Possibly but not necessarily, the exact dimensions of this shape or the corresponding surface profile are substantially the same. For example, these dimensions can be the amplitude and / or period width of shape features with alternating continuity such as protrusions and depressions. It has been shown that pressure ratios can be compared with the help of such similar shapes.

[0042] This applies in particular to the case where the side of the separator on which the seal is arranged has a shape that is complementary to the side of an adjacent separator, for example the side that follows in the stacking direction. In this case, for example, the outer surface of the seal can be locally recessed, but in the stacking direction it can be opposite to a complementary raised area of ​​an adjacent separator, or facing such an area. Additionally or alternatively, for example, the outer surface of the seal can be locally convex, but in the stacking direction it can be opposite to a complementary recessed area of ​​an adjacent separator, or facing such an area. This means that the height profiles of the outer surface of the seal and the relative areas of the adjacent separators can be equalized at least in some sections, which can equalize the pressure ratios generated during assembly and in particular when compressing the electrochemical system. In addition, the topographic outer surface of the seal can also be adjusted to be geometrically incompatible in the longitudinal direction, that is, in particular to be adjusted to be geometrically incompatible with the side of the adjacent separator that follows in the stacking direction.

[0043] According to a further embodiment, the region that is similar in shape to the outer surface of the seal includes a part of one of the distribution regions on the corresponding one of the first side and the second side. Thus, the seal can span the distribution region or its web / channel structure at least in some sections in the manner described above. For example, a section of the seal or its outer surface can extend transversely to the longitudinal channel axis of the distribution region or its web-shaped channel structure. Such a distribution region spanned by the seal preferably does not create a fluid-conducting connection between the through-opening and the flow field, for example. Instead, this connection is deliberately interrupted by the seal. Such a distribution region can be complementary in shape to the distribution region on the opposite side of the separator. This opposite distribution region can specifically establish a fluid-conducting connection. The fluid-sealed distribution region can be produced by embossing or other molding processes for producing the opposite fluid-conducting distribution region.

[0044] According to a further embodiment, the outer surface of the seal faces away from the corresponding one of the first side and the second side on which the seal is arranged. Additionally or alternatively, the outer surface of the seal can be arranged to contact another component of the electrochemical system (such as the MEA or the cell stack frame), which extends at least in some regions parallel to the separator and / or directly opposite the separator. Additionally or alternatively, the outer surface of the seal can extend along the flat surface plane of the plate component.

[0045] According to one embodiment, the height profile varies alternately at least in some sections. For example, the height profile can have an alternating sequence of protrusions and depressions, with the protrusions preferably having the same dimensions at least in the height direction, and the depressions preferably having the same dimensions at least in the height direction, especially along the direction of the longitudinal extension of the seal. The alternating sections can be evenly spaced apart. This can correspond to a regular and / or periodic alternation. However, they can also be irregularly spaced apart. This allows, for example, for variations in the web and / or channel width of the distribution region to be taken into account.

[0046] According to one embodiment, the outer surface of the seal is corrugated at least in some sections. This can be specifically understood as meaning that the topographical shape of the outer surface includes an alternating sequence of valleys and peaks. The transition between these alternating sections can be rounded. The corrugation can represent a particularly suitable adaptation for pressure equalization purposes to the adjacent region of the separator or the opposite region of the adjacent separator (and / or to the region of the adjacent separator facing the outer surface).

[0047] As described above, the height dimension of the seal can extend orthogonally to the flat surface plane of the plate component.

[0048] According to one embodiment, the height difference between a local lowest point and an adjacent local highest point on the outer surface of the seal is between 0.01 mm and 1 mm. The lower limit of this range can also be 0.2 mm. The upper limit of this range can also be 0.8 mm. In particular, this range can thus be between 0.2 mm and 0.8 mm.

[0049] According to one embodiment, the distance between a local lowest point and an adjacent local highest point on the outer surface along the longitudinal extension of the seal is between 0.1 mm and 2.5 mm.

[0050] Any local lowest point disclosed herein can be surrounded by recesses and / or valleys of the disclosed alternating protrusion profile or alternating landform shape type. Any local highest point disclosed herein can be surrounded by protrusions and / or peaks of the disclosed alternating protrusion profile or landform shape type.

[0051] It has been shown that a reliable sealing effect can be achieved with the above height difference and distance.

[0052] According to a further embodiment, the seal has at least two sealing segments protruding from the plate member, for example in the form of sealing lips, which can in particular extend parallel to one another. Each of the sealing segments can have an outer surface which, at least in some segments and at least in the non-installed state of the electrochemical system, is relief-shaped and / or has a varying height profile when viewed in the direction of the longitudinal extension.

[0053] The invention also relates to an electrochemical system, in particular an electrolyser, which comprises a plurality of separator plates according to any aspect disclosed herein, wherein the separator plates are arranged in a stack. For example, the separator plates can be stacked on top of one another along a stacking axis. The separator plates can be aligned parallel to one another. Further components of the electrochemical system can be arranged between two separator plates directly adjacent along the stacking axis, the two separator plates being in particular an MEA, a cell frame, a porous transport layer, i.e. a PTL, or a gas diffusion layer, i.e. a GDL. In particular, such a stack including any other components can be mechanically compressed before the electrochemical system is put into operation. The deformation of the seal described herein will occur at the latest due to this compression.

[0054] In the electrochemical system, for each pair of adjacent separator plates, at least one seal having a relief-shaped outer surface can face away from the first separator plate in the pair and towards the second separator plate in the pair. In particular, this seal can bear against this second separator plate, or in other words, be on the second separator plate. This enables the outer surface of this seal to be reliably supported, at least indirectly, on the second separator plate to achieve a reliable sealing effect.

[0055] According to one embodiment, at least in the uncompressed state of the stacked separators, the topographical outer surface shape of at least one seal of the first separator is designed to be complementary to the area of the second separator that is opposite to and / or faces the outer surface. As a result of compression, the topographical shape and / or height profile of the separator can better adapt to the topographical shape and / or height profile of the second separator. Alternatively or additionally, the topographical shape and / or height profile of the separator can be adjusted towards a more consistent topographical shape and / or a more consistent height profile, for example towards a more uniform shape.

[0056] In this case, the opposing components can be particularly understood as being at least indirectly continuous, whereby the latter allows for additional components to be present between the opposing components. In particular, this can be understood to mean that the corresponding features face each other, for example along a certain axis (especially the stacking axis mentioned here), even if additional components can be positioned between them.

[0057] According to one embodiment, at least one seal of the second separator having a topographical outer surface faces away from the first separator. The seal can, for example, be opposite to and / or face a third separator adjacent to the second separator. This embodiment can be accompanied by the fact that for each through-opening, only one seal having a topographical outer surface is provided between two adjacent separators (more precisely, between their plate components). This achieves reliable sealing and a compact stacking height.

[0058] According to one embodiment, at least one membrane electrode assembly, i.e., MEA, is arranged between the separators of each pair of adjacent separators. The seal of the first separator can be in direct contact with the membrane electrode unit. The seal of the first separator can be supported on the second separator via the MEA. As a result of the pressure compensation effect of the topographical outer surface disclosed herein, the seal can be uniformly supported on the MEA and has a correspondingly consistent and reliable sealing effect.

[0059] According to a further embodiment, in addition to the membrane electrode unit, a cell frame is arranged between the separators of each pair of adjacent separators and on both sides of the membrane electrode unit, wherein the seal of the first separator rests against one of the cell frames. More precisely, the seal can rest against the cell frame that is arranged on the side of the MEA facing the first separator.

[0060] Generally, the cell frame can be a flat component that can be arranged substantially parallel to the separators in the stack of the electrochemical system disclosed herein.

[0061] The battery cell frames can be constructed in the same way. They can be assembled or combined to form a complete battery cell frame or interact with each other in such a way. They can be regarded as partial battery cell frames of the corresponding overall battery cell frame. Each battery cell frame can each have such a recess: at least one other component of the electrochemical system is accommodated in the recess and is particularly exposed therein. For example, the component can be the above-mentioned MEA. Each battery cell frame can each provide a strengthening function and can in particular be harder than the accommodated component and in particular the MEA. According to one variant, the battery cell frame comprises a plastic material, in particular polyethylene naphthalate, i.e. PEN. Generally, the material of the battery cell frame can be different from the material of the accommodated component and in particular the MEA.

[0062] The components accommodated by the battery cell frame and in particular between the battery cell frames can comprise at least one edge region of the component that abuts against the battery cell frame and / or is enclosed between the battery cell frames. The battery cell frame can surround or enclose the accommodated component in a frame-like manner. This particularly relates to the inner circumference or inner edge of the above-mentioned accommodation recess, which can be closed and / or have a corresponding frame-like shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Exemplary embodiments of the present invention will be explained below with reference to the drawings. Similar or equally effective features can be provided with the same reference numerals across all the drawings. In a particular figure, not all instances of the shown features are provided with the reference numeral assigned to that feature.

[0064] Figure 1 The basic structure of an electrochemical system according to an embodiment of the present invention in the form of an electrolyzer is shown.

[0065] Figure 2 The first side of a separator according to an embodiment of the present invention is schematically shown, as it can be used in a system as shown, for example. Figure 1 as shown.

[0066] Figure 3 The second side of a separator according to an embodiment of the present invention is schematically shown, as it can be used in a system as shown, for example. Figure 1 as shown.

[0067] Figure 4 A cross-sectional view through a pair of separators stacked on top of each other in an uncompressed state is shown, where the separators can be formed according to an embodiment of the present invention and in particular according to a variant of Figure 2 and Figure 3 to form.

[0068] Figure 5 Shows Figure 4 a pair of separators in a compressed state.

[0069] Figure 6 Yes Figure 5 Partial perspective view of the separator in the state shown.

[0070] Figure 7 Shows a further example of a cross-sectional view through a pair of separators stacked on top of each other in the uncompressed state, where the separators can be formed according to an embodiment of the invention and in particular according to Figure 2 and Figure 3 variations.

[0071] Figure 8 Shows in the compressed state Figure 6 a pair of separators. Detailed description

[0072] Figure 1 Shows an electrochemical system 10 according to an embodiment of the invention. The electrochemical system 10 is an electrolyzer. The basic structure of this electrolyzer explained here is known in principle. The modifications according to the invention disclosed herein relate in particular to the construction of the separator 18.

[0073] The electrolyzer includes a repeating sequence of components stacked as described below. This stack is arranged and clamped between two boundary plates 14, i.e., it is mechanically pressed together and compressed. All components of the stack are stacked along the stack axis S, or in other words, are linearly adjacent to each other.

[0074] Bipolar plates 16 are provided in the stack, which bipolar plates are composed of separators 18, and the separators 18 are here mounted in a single layer. Each separator 18 includes a plate member 19, which plate member 19 is formed from a single metal sheet and is in particular embossed and / or stamped. The separator 18 also includes a seal 33 as explained below.

[0075] If the separator 18 is mentioned hereinafter, unless otherwise stated or obvious, the separator 18 may be synonymous with reference to its plate member 19 and synonymous with specifically referring to the plate member 19.

[0076] The separator 18 has outer faces facing surfaces that face away from each other. These surfaces each form the anode side or the cathode side of the separator 18, which is why it correspondingly forms the bipolar plate 16. More precisely, the first outer face facing the surface of the separator 18 is opposite to the porous transport layer, i.e., the PTL 20, and is in particular placed against the porous transport layer. The PTL 20 includes or consists of titanium or a titanium alloy. The corresponding surface or corresponding side of the separator 18 forms the anode side of the bipolar plate 16.

[0077] The corresponding other outer face of the surface of the separator 18 facing each bipolar plate 16 is opposite to the gas diffusion layer, i.e., GDL 22, and is placed in particular against the gas diffusion layer. The GDL 22 comprises carbon or consists of carbon, and in particular consists of a carbon fleece. The corresponding surface or side of the separator forms the cathode side of the bipolar plate 16.

[0078] The membrane electrode assembly 24, i.e., MEA, is arranged between the PTL 20 and the adjacent GDL 22. This forms a catalyst-carrying part coated with a catalyst material, see Figure 1 the catalyst layer 26 marked as an example in

[0079] The cell unit frame assemblies 31 are also shown, each of which comprises two (partial) cell unit frames, between which the components of the electrochemical system 10 are accommodated. These components can be exposed in the accommodation recesses 29 of the corresponding cell unit frame assemblies, for example, if the component is a PTL or a GDL. Other components and in particular the MEA can be clamped between the opposing (partial) cell unit frames and / or squeezed or glued between them. The individual (partial) cell unit frames are not individually marked in Figure 1 and are explained below.

[0080] During the operation of the electrolyzer, water is fed along the anode side of the bipolar plate 16. In Figure 1 , the flow direction of water can be, for example, vertically upward or vertically downward (or vice versa), or from right to left (or vice versa).

[0081] By interacting with the adjacent catalyst layer 26 and by applying a voltage using the voltage source 28, water is decomposed into oxygen, electrons, and positively charged hydrogen ions. The hydrogen ions diffuse to the cathode side, where they combine with electrons to form hydrogen. In order to reach the catalyst layer 26, water must penetrate the adjacent PTL 20.

[0082] Figure 2 A single separator 18 that can be used in the Figure 1 system 10 is shown. In Figure 2 , one anode side 17 of the separator 18 faces the observer. The separator 18 comprises a plurality of through openings 30, 32. More precisely, two hydrogen through openings 32 are provided, each of which is surrounded by a seal 33. The seal 33 prevents the hydrogen through openings 32 from being fluid-conductively connected to the region of the shown anode side 17 of the separator 18 that is located outside the seal 33 or the region of the anode side 17 enclosed thereby.

[0083] In addition, as an example, four water through openings 30 are provided. These water through openings are not sealed against the flow field 38 of the shown anode side 17 and are thus fluid-conductively connected thereto. However, the water through openings 30 are sealed from the surrounding environment of the electrolyzer, as is the flow field 38. For the sake of clarity, such seals are not shown in Figure 2 . For example, it can be located on the separator 18 or in an adjacent component.

[0084] The medium guiding structure 42, which consists of a number of distribution areas 40 and the flow field 38, is pressed into the anode side 17, with the distribution areas and the flow field each having a channel web arrangement. The medium guiding structure 42 includes a flow area for supplying water by means of the water through openings 30.

[0085] The medium guiding structure 42 includes a plurality of channels 34 and webs 36, with the webs 36 extending between and separating the channels, in particular spatially and / or structurally separating the channels. The extending directions of the channels 34 and the webs 36 and thus the corresponding longitudinal axes (which are not shown separately) extend vertically in Figure 2 (except for the distribution area 40 of the through opening 32 discussed below). Thus, the channels 34 and the webs 36 each extend between opposite water through openings 30.

[0086] The flow area is partly formed by the flow field 38, which is located in the electrochemically active area of the system 10 and in which the conducted water participates in the electro-chemical reaction of the electrolyzer. In addition, the flow area is partly formed by the distribution areas 40, in which no electro-chemical reaction takes place, or optimally a significantly reduced electro-chemical reaction takes place. These distribution areas 40 are each assigned to one of the through openings 30, 32, thus fluid-conductively connecting them to the flow field 38 at least in the non-sealed case disclosed here.

[0087] It can be seen that the corresponding seal 33 in the shown example is not completely flush with the edge area 35 of the associated through opening 32, but this can also be provided according to the embodiment. However, in the shown example, the corresponding seal 33 spans the distribution area 40 of the associated through opening 32. A partial area 41 of the distribution area 40 is thus still fluid-conductively connected to the through opening 32, but not to the adjacent remaining area of the distribution area 40, let alone the flow field 38. In all embodiments shown here, the corresponding seal 33 is made of an elastomeric material and is molded onto the separator 18, more precisely onto its plate part 19.

[0088] In a manner known per se, the channels 34 and webs 36 on the cathode side 21 of the separator 18 that face away from the observer form a complementary channel-web arrangement. On this cathode side 21, the water through-opening 30 is fluid-sealed by the seal 33, and the hydrogen through-opening 32 is fluid-connected to the flow region. This is shown in Figure 3 as shown in Figure 3 a view of the cathode side 21 of the separator 18 in Figure 2 is shown.

[0089] Alternatively, the flow field 38 can also be smooth and without channels and webs. Thus, the channels and webs preferably considered in the context of the present disclosure are particularly located in the distribution region 40, especially those that cooperate with the seal 33.

[0090] Figure 3 The seal 33 shown is constructed in the same manner as the seal 32 in Figure 2 . Optionally, they in turn span the distribution region 40, which is connected to the through-opening 30 enclosed by the seal 33.

[0091] A partial view of the separator 18 is shown below, where the separator 18 can be constructed in particular according to the examples of Figure 2 and Figure 3 . The seal 33 discussed below can be any one of the seals 33 for sealing any through-openings 30, 32 of the separator 18, and in particular any one of the seals 33 in Figure 2 and Figure 3 .

[0092] Figure 4 A detailed view D of a pair of separators 18 having a sectional axis A-A is included, as well as a sectional view through the separator 18 along this sectional axis A-A. Figure 4 The following state is shown: The separators 18 are stacked on top of each other and accommodate two cell frame assemblies 31, which, for example, accommodate a PTL or GDL not shown separately and an MEA 24 arranged between the cell frame assemblies 31. The cell frame assemblies 31 are additional components of the electrochemical system 10 in which the separators 18 are installed.

[0093] First referring to the upper separator 18 in the sectional view of Figure 4 , it can be seen that the sectional plane extends through a part of the seal 33 that extends along a region of the separator 18 that includes a part of the medium guiding structure 42. In particular, this can be a section of the distribution region 40, as shown by the exemplary position of the axis B included in the sectional plane A-A in Figure 2 .

[0094] Thus, by means of the channels 34 and webs 36 of the distribution area 40 along which the shown part of the seal 33 extends, the area of the partition 18 is topographical or in other words uneven and has an irregular height profile. A height axis H is shown, which is generally orthogonal to the plane of the partition 18 not shown separately.

[0095] As described, Figure 2 an axis B is shown, which is placed in Figure 4 the cross-sectional plane A-A of, and is also shown in Figure 4 . Figure 2 It is shown that the axis B extends along the edge area 35 of the through-opening 32, which is sealed by the Figure 4 shown seal 33. Thus, Figure 4 the cross-sectional view of shows the section of the seal 33 extending along the through-opening 32. The longitudinal direction of the extension of the seal 33 or its outer surface 44 correspondingly extends along the axis B in Figure 4 and thus extends horizontally from left to right (or vice versa).

[0096] Returning to Figure 4 , it can be seen that the seal 33 completely fills the surface depressions and protrusions of the partition 18 on its inner side facing the partition 18. This is because when the elastomeric seal is molded onto the partition 18 and completely fills the partition 18, the elastomeric seal automatically adapts to the height profile of the partition 18. The interior of the seal 33 thus mimics the channels 34 and webs 36 of the partition 18. The seal 33 is topographically shaped on its outer surface 44 facing away from the partition 18. This topographical structure is defined by the geometry of the injection mold. More precisely, it also has a varying height profile H. In the example shown, this variation is substantially the same as the variation of the partition 18 adjacent to the outer surface 44 and along the longitudinal extension direction, i.e., the axis B.

[0097] For example, the outer surface 44 of the seal 33 is corrugated in the same way as the side of the partition 18 here on which the seal 33 is molded and along which the seal 33 extends. At the positions where the partition 18 on this side has indentations in the form of channels 34 or valleys, the outer surface 44 of the seal 33 also has depressions 37 or valleys. At the positions where the partition 18 on this side has protrusions in the form of ridges 36 or peaks, the outer surface 44 also has protrusions 39 or peaks.

[0098] As previously described, the distribution areas 30 of the partitions 18a, 18b are each shaped in a complementary manner such that the webs 34 formed on the first side or surface of the partitions 18a, 18a form channels 36 on the second side or surface. Similarly, the channels 36 formed on the first side or surface form webs 34 on the second side or surface. In Figure 4In the case previously discussed, it was considered that the seal 33 of the partition 18a was molded directly to its side, as well as its web 34 and channel 36, the seal 33 reproducing the web channel topography of this side in the form of depressions 37 and protrusions 39 on its outer surface 44.

[0099] For example, the protrusions 37 and recesses 39 are defined from the perspective of an observer looking forward at the corresponding side of the partition 18a, i.e., from the perspective of the observer looking forward at the corresponding side of the partition 18a. Figure 4 Similarly, the protrusion 37 and the recess 39 can be formed relative to the plane of the partition 18a. Figure 4 The protrusions 37 and recesses 39 in the cross-sectional view of and associated with the stacking axis S or the height axis H can each be defined as a protrusion 37 or recess 39 vertically downward and / or orthogonal to the axis B. The apex of the protrusion 37 comprises the highest local point, and the apex of the recess 39 comprises the lowest local point of the corresponding surface. The distance between adjacent highest and lowest local points along the height axis H and longitudinally along the axis B can have any value disclosed herein.

[0100] The dimensions of the depressions 37 and protrusions 39, for example in terms of amplitude and / or period width of the varying height profile, may be identical when comparing the side of the diaphragm 18 facing the seal 33 with the outer surface 44 of the seal 33. However, they may also deviate from each other, for example by no more than 20%.

[0101] Figure 4 The outer surface 44 of the upper seal 33 is shown in contact with the upper battery cell frame assembly 31. On the other hand, the lower battery cell frame assembly 31 rests against the upper surface of the lower separator 18b. The lower separator 18b also has a seal 33, which is formed similarly to the upper seal 33 and has a corresponding topographic outer surface 44. This outer surface 44 is in turn adjacent to an adjacent battery cell frame assembly 31 in the remainder of the stack of the electrochemical system 10, which is not shown. Therefore, the outer surface 44 of the seal 33 of the upper separator 18a faces in the direction of the adjacent lower separator 18b. On the other hand, the seal 33 of the adjacent lower separator 18b, and in particular its outer surface 44, faces away from the upper separator 18a.

[0102] In the stack of electrochemical system 10, adjacent Figure 4 The partitions 18a and 18b shown in the figure are arranged so that their sides which follow each other and face each other along the stacking axis S are designed complementary to each other. Thus, the inner side of the upper partition 18a has a protrusion or ridge 36 in the area where the upper side of the lower partition 18b has a depression or channel 34. Similarly, the inner side of the upper partition 18a has a depression or channel 34 in the area where the upper side of the lower partition 18 has a protrusion or ridge 36.

[0103] When viewed along the stacking axis S, the aforementioned upper and inner sides of the separators 18a and 18b are placed opposite to each other and at least indirectly bear against each other when compressed. The protrusions and depressions can in turn be defined from the perspective of an observer who looks forward at the corresponding side or area, which is different from Figure 4 the perspective of

[0104] When pressed together, a compressive force acts between the adjacent separators 18a and 18b, whereby the separator 18 is the most dimensionally stable component among the shown plurality of components. In particular, the seal 33 bears on the adjacent separators 18 and is supported by the deformation of other components such as the battery cell frame assembly 31 and the MEA 24 arranged therebetween, and these other components deform during compression.

[0105] The compressive force extends along the stacking axis S. It can be seen that in Figure 4 the example of

[0106] According to the present invention, it has been recognized that when the outer surface 44 has a non-topographical configuration, this results in a substantially non-uniform deformation of the seal 33. This can lead to non-uniform contact forces of the seal 33 on the adjacent battery cell frame assembly 31. This can be at least partially compensated for by the topographical configuration of the outer surface 44 disclosed herein.

[0107] The latter is confirmed by Figure 5 which Figure 5 shows a cross-sectional view of a pair of separators 18 in a compressed state similar to Figure 4 . It can be seen that even in the area where the seal 33 faces the recess (i.e., the channel) 34 of the adjacent separator 18, the outer surface 44 of the upper seal 33 is in full contact with the opposing battery cell frame assembly 31, that is, the seal 33 bears against these adjacent separators.

[0108] Figure 6 is Figure 4 andFigure 5 Perspective view of a cross-section. It shows paired separators 18 and partial segments of the components 24, 31 enclosed therebetween. In particular, this view also shows the segments of these components in the transverse direction Q, which extends transversely to Figure 4 the axis B in Figure 2 As shown, this transverse direction Q corresponds to the direction transverse to the edge region 35 of the through-opening 32 sealed by the seal 33.

[0109] As shown, when viewed along this transverse direction Q, the seal 33 has two adjacent sealing segments 45, each of which forms a sealing lip. Each of these sealing segments 45 has a topographical outer surface 44 according to the above-described variant. It has been shown that an improved sealing effect can be achieved with this configuration as compared to a single large-area sealing segment 45. However, within the scope of the present disclosure, it is also possible in principle to provide only a single sealing segment 45 and a single outer surface 44.

[0110] Figure 7 and Figure 8 shows a view similar to Figure 4 and Figure 5 as a further exemplary embodiment. However, they relate to the case where the MEA 24 is disposed between the separators 18 without an additional battery cell frame assembly 31 enclosing them. Figure 7 again shows the uncompressed state, while Figure 8 shows the compressed state. For more details and the achieved effects, reference is made to the description in Figure 4 and Figure 5 .

Claims

1. A separator (18) for an electrolyser or other electrochemical system (10), characterized in that The partition (18) has at least one plate component (19), and the plate component includes: a first side (17) and a second side (21) facing away from said first side, a flow field (38) on each of the first side (17) and the second side (21), a plurality of distribution areas (40) with a plurality of channels, wherein every two adjacent channels (34) are separated by a web (36), and ● a plurality of through openings (30, 32), wherein each of the through openings (30, 32) is connected to the flow field (38) on one of the first side (17) and the second side (21) in a fluid-conducting manner via one of the distribution areas (40), and each is fluid-sealed with the flow field (38) on the one side (17, 21) on the corresponding other side of the first side (17) and the second side (21) by a seal (33) of the partition (18), In which, at least one of the seals (33) extends at least in some sections along an edge area (35) of the through opening (30, 32) sealed by the seal (33) and has at least one outer surface (44) which is topographical at least in some sections when viewed along the longitudinal extension, at least in the uninstalled state of the electrochemical system (10).

2. The separator (18) according to claim 1, characterized in that The sealing element (33) is made of an elastomeric material.

3. A separator (18) according to any one of the preceding claims, characterized in that The topographical configuration of the outer surface (44) includes: the outer surface having a varying height profile.

4. A separator (18) according to any one of the preceding claims, characterized in that The outer surface (44) is shaped similarly to a region of a corresponding one of the first side (17) and the second side (21): the seal (33) is arranged on the region and the outer surface (44) extends along the region.

5. The separator (18) according to claim 4, characterized in that The area comprises a portion of one of the allocation areas (40).

6. A separator (18) according to any one of the preceding claims, characterised in that The outer surface (44) faces away from a corresponding side of the first side (17) and the second side (21) on which the seal (33) is arranged.

7. The separator (18) according to claim 3, characterized in that The height profile varies alternately at least in some sections.

8. A separator (18) according to any one of the preceding claims, characterised in that The outer surface (44) is corrugated at least in sections.

9. A separator (18) according to any one of the preceding claims, characterised in that The height dimension of the seal (33) extends orthogonally to the planar surface of the plate member (19).

10. A separator (18) according to any one of the preceding claims, characterised in that The height difference between a local lowest point of the outer surface (44) and an adjacent local highest point of the outer surface (44) is between 0.01 mm and 1 mm, in particular between 0.2 mm and 0.8 mm.

11. A separator (18) according to any one of the preceding claims, characterised in that The distance along the longitudinal extension of the seal between the local lowest point of the outer surface (44) and the local highest point of the outer plane (44) adjacent to the local lowest point is between 0.1 mm and 2.5 mm, in particular between 1 mm and 2 mm.

12. A separator (18) according to any one of the preceding claims, characterised in that The seal (33) comprises at least two sealing sections (45) protruding from the plate part (19), wherein each of the sealing sections (45) has an outer surface (44) which, at least in some sections, is topographical in the direction of the longitudinal extension, at least in an unmounted state of the electrochemical system (10).

13. An electrochemical system (10), in particular an electrolyser, comprising a plurality of separators (18) according to any one of the preceding claims, wherein: The baffles (18) are arranged in a stack.

14. The electrochemical system (10) according to claim 13, characterized in that In each pair of adjacent baffles (18), at least one seal (33) having a topographical outer surface (44) faces away from a first baffle (18) of the pair and toward a second baffle (18) of the pair and is supported on the second baffle (18).

15. The electrochemical system (10) according to claim 14, characterized in that At least in the uncompressed state of the stacked partitions (18), the topographical outer surface (44) of the at least one seal (33) of the first partition (18) is designed to be complementary to the area of ​​the second partition (18) opposite to and / or facing the outer surface (44).

16. The electrochemical system (10) according to claim 14 or 15, characterized in that The at least one seal (33) of the second separator (18) having a topographical outer surface (44) faces away from the first separator (18).

17. The electrochemical system (10) according to any one of claims 14 to 16, characterized in that At least one membrane electrode unit (24) is arranged between the separators (18) of each pair of adjacent separators (18), and the seal (33) of the first separator (18) abuts against the membrane electrode unit (24).

18. The electrochemical system (10) according to claim 17, characterized in that In addition to the membrane electrode unit (24), there is a cell frame (27) arranged between the separators (18) of each pair of adjacent separators (18) and on both sides of the membrane electrode unit (24), wherein the seal (33) of the first separator (18) rests against one of the cell frames (27).

Images