Sealing arrangement, arrangement for an electrochemical system and electrochemical system

Abstract

The present invention relates to a sealing arrangement for an electrochemical system which, when installed in the electrochemical system, can withstand loads transverse to a layer plane, wherein the sealing arrangement comprises: a frame-shaped layer with a recess, wherein the recess is configured to surround an electrochemically active area of ​​the electrochemical system in a frame-like manner, and wherein the recess has an inner edge, as well as an elastomeric sealing element which bears against the inner edge of the recess with an inner edge region and projects into the recess with an outer edge region, wherein the outer edge region comprises, at least on a first outer side, at least partially a bearing area for a component of the electrochemical system which is lowered relative to an adjacent first region of the sealing element.

Description

[0001] The present invention relates to a sealing arrangement, an arrangement for an electrochemical system, and an electrochemical system. The electrochemical system can be, for example, a fuel cell stack, an electrolyzer, or a redox flow battery.

[0002] Electrochemical systems such as electrolyzers or fuel cell stacks typically comprise a stack of electrochemical cells, each with multiple layers, including at least one separator plate and a membrane electrode assembly (MEA), and each cell bounded by two adjacent separator plates. The stack of electrochemical cells may have two end plates that press the cells together, providing stability to the assembled stack. Furthermore, the electrochemical cells may include gas diffusion layers (GDL) or porous transport layers (PTL) positioned between the separator plate and the MEA.The separator plate can fulfill several functions: indirect electrical contacting of electrodes in the membrane electrode assembly (MEA), separation of media such as water, oxygen, or hydrogen, and electrical connection of adjacent electrochemical cells. The separator plate is also often referred to as a bipolar plate.

[0003] The separator plate typically includes at least one or more through-openings, sometimes also called ports, as inlets or outlets for guiding a fluid through the separator plate. It also typically includes a flow field, in other words, a flux field, with an electrochemically active area and a fluid guide structure for directing the fluid between the through-opening and the flux field. The separator plate can, for example, be single-layered or multi-layered.

[0004] While separator plates in fuel cells are often two-layered to allow cooling fluid to flow between the two layers, separator plates in electrolyzers are typically single-layered, as additional cooling is not necessary. However, two-layer separator plates do exist in electrolyzer applications. In this case, for example, the flux field can be designed as an additional metallic layer arranged on a metallic base plate to form the bipolar plate.

[0005] In addition to the aforementioned separator plates, MEA, GDL, or PTL, further components may be incorporated. For example, cell frames and / or cell seals can be arranged between adjacent separator plates to create a fluidic seal between the cells. The stack of electrochemical cells must be fluidically sealed from the outside environment because the fluid or medium inside the electrochemical cells is often pressurized compared to the external pressure. This fluid can consist of, for example, hydrogen, air or oxygen, water, and / or mixtures thereof. In an electrolyzer, the pressure difference between the environment and the interior of an electrochemical cell can frequently exceed 20 bar. Thus, the pressure on the product side, for example, the H₂ side, can reach up to 40 bar, while the pressure on the reactant side, for example, the H₂O side, is only up to 2 bar.

[0006] It is therefore usually necessary to seal the fluid flow field from the environment and also within the electrochemical system. For this purpose, the electrochemical system can have at least one cell frame surrounding the outer edge of each electrochemical cell to achieve a sealing effect. Furthermore, the electrolyzer can include one or more sealing layers or cell seals for each electrochemical cell.

[0007] Sealing the flow field and / or the passage openings often involves the use of sealing beads molded into the separator plates, elastomer seals injected onto a metallic layer of the separator plate, or combinations thereof.

[0008] It was found that unexpected performance losses or even functional losses can still occur with the existing systems.

[0009] There is therefore a continuous need to improve the performance and functionality of electrochemical systems. The present invention provides a solution to this problem.

[0010] The present invention is defined by the subject matter according to the independent claims. Further developments are specified in the dependent claims, the following description, and the figures.

[0011] According to the invention, the insufficient interaction of elastomer seals and adjacent components of an electrochemical system, and especially an electrochemical cell, has been identified as a cause of the previously observed conduction and functional losses. In particular, components such as a PTL (percutaneous transducer) have previously been inadequately or unfavorably supported at the edge of the flow field. As a result of compression and / or pressurization, such a component can therefore be subjected to excessive local stress and may also be deformed or damaged. This can also apply to other components, such as a MEA (mechanical electrical junction) adjacent to a PTL, which no longer receive the intended structural support to a sufficient degree.As a result, these components can buckle or tear, and / or the continuous contact and thus the mutual support of these components can be interrupted, at least locally. This can lead to leaks, performance losses, or general functional problems.

[0012] A specific, exemplary problem identified is that a PTL (Power Transfer Fluid) typically cantilevers laterally on the anode side via an outermost rib or an alternative geometry of a flux field, and this cantilevered area is structurally unsupported or only inadequately supported. If fluid pressure is then applied on the cathode side, a MEA (Mechanical Energy Exchanger) can brace itself against the cantilevered area of ​​the PTL and deform it. Both the MEA and the PTL can then rupture or be overstretched.

[0013] Accordingly, a sealing arrangement for an electrochemical system, in particular for a fuel cell and / or a fuel cell stack, is disclosed, which is load-bearing when installed in the electrochemical system transversely to a layer plane, in particular as a result of compression of the fuel cell stack, wherein the sealing arrangement comprises: • a frame-shaped layer, which can also be called a cell frame, with a recess, wherein the recess is configured to surround an electrochemically active region of the electrochemical system in a frame-like manner, and wherein the recess has an inner edge, as well as • an elastomeric sealing element which rests against the inner edge of the recess with an inner edge area and projects into the recess with an outer edge area, wherein the outer edge region and preferably its outermost part comprises, at least on a first outer surface, at least section by section, a bearing area for a component of the electrochemical system, such as in particular a PTL or another planar and / or fluid-permeable component of the electrochemical system, which is located in particular in an electrochemically active region of the system and / or at least partially delimits it. The bearing area is recessed relative to an adjacent and in particular an adjoining first region of the sealing element and / or an adjacent outer surface of the layer.

[0014] The layer plane can be defined by the layer and / or extend at least sectionally parallel to it and, in particular, to at least one of its outer surfaces. Specifically, the layer plane can extend along the layer and / or correspond to a median plane of the layer or run parallel to it. The median plane can be a virtual geometric plane that passes through or along the average thickness(es) of the plate. In other words, the median plane can encompass a position of average thickness. Accordingly, it can encompass and / or define a position of average thickness of the layer across its entire extent.

[0015] The component that can rest on the support area can run essentially or completely parallel to the layer plane.

[0016] The layer can be made of a metallic material such as aluminum, steel, titanium, or stainless steel, plastic, and / or combinations thereof. Since the layer preferably does not come into contact with the fluid during the intended use of the sealing arrangement, it can be made of a material that may be less electrochemically resistant, such as aluminum or steel.

[0017] For example, the sealing element is made of fluororubber, FKM, and / or ethylene propylene diene monomer rubbers, EPDM, and / or a silicone. The layer and / or the sealing element can be one-piece components or, in other words, integral components with a homogeneous material composition.

[0018] At least in one state installed in the electrochemical system, the recess can face the electrochemically active area and / or expose at least sections of it. The inner edge can encircle the recess and / or the recess can have a closed perimeter, with the perimeter being formed by the inner edge. The layer can generally be made of a non-elastomeric material and, in particular, of a metallic material, as shown in the examples above.

[0019] The inner and outer edge regions of the elastomeric sealing element can be opposite each other and / or facing away from each other. This can be particularly true when viewed along an axis that extends in or parallel to the layer plane. For example, the inner edge region can face away from a geometric center of the recess, while the outer edge region can face this geometric center. The outermost part of the outer edge region can form an outermost end, for example, when viewed along an axis that is orthogonal to the inner edge and / or parallel to the layer plane.

[0020] On the second outer surface, facing away from the first outer surface, the sealing element can rest against a separator plate. It can also rest against the separator plate, preferably with one side facing away from, or at least further away from, the component received in the bearing area.

[0021] The contact of the inner edge region of the sealing element with the inner edge of the recess can, in particular, include overmolding or other contact, especially form-fitting and / or force-fit contact, between the inner edge region and the inner edge. In particular, the inner edge region can, for example, overlap and / or form the inner edge at least partially as a result of overmolding.

[0022] The recess can generally define an area within the layer that remains free, at least before the elastomeric sealing element is attached, and / or does not include the layer material. Due to the elastomeric sealing element, and in particular its projection into the recess, a portion of the recess that initially remains free can be covered and / or occupied as a result of the elastomeric sealing element's attachment.

[0023] The first outer surface of the sealing element, on which the bearing area is formed, can be encompassed by the bearing area and / or more generally by the sealing element. The first outer surface can face the component and / or be opposite it. It can run parallel to the component and / or to the layer plane.

[0024] The support area can form a support or counter-support for the component. In particular, the support area can be in contact with the component, at least partially, and / or support it. Preferably, the component simply rests on the support area and is not rigidly connected to it, e.g., not by a material bond or by means of mechanical fasteners. In particular, the component can rest on the support area only with its side facing the support area, but not be surrounded by it on several sides or, for example, inserted, molded, or plugged into it. This facilitates assembly and reduces the risk of damage.

[0025] By lowering the bearing area, a stepped shape of the outer edge of the sealing element can be defined. The lowering and / or the stepped shape can be present, in particular, along an axis that runs transversely to the layer plane. The bearing area can comprise at least one bearing surface. This surface can extend, at least partially, parallel to the layer plane and / or to the component. The bearing area, or at least its aforementioned bearing surface, can be essentially smooth and / or flat to ensure uniform contact conditions with the component. At least this bearing surface can be lowered relative to the adjacent first area.

[0026] The bearing area, and in particular its bearing surface, can be connected to the adjacent first area via an edge surface of the sealing element. The adjacent first area can run essentially parallel to the plane of the surface and / or to the bearing surface. The edge surface, or at least a portion thereof that is lowered relative to the adjacent first area, can optionally be considered a component of the bearing area. The edge surface can extend at an angle to the bearing area, and in particular to its bearing surface, especially substantially or completely orthogonally to it. The edge surface can form a kind of riser and / or be oriented in the manner of a riser, especially relative to the bearing area and in particular to its bearing surface. In particular, the edge surface can define a step height, especially within the lowered area of ​​the sealing element encompassing the bearing area.The bearing area and in particular its possible bearing surface can form a kind of step and / or be oriented in the manner of a step, especially relative to the edge surface.

[0027] The contact area can, preferably in contrast to the first area and / or in contrast to the edge surface of the sealing element, make contact with the component at least partially or, in other words, bear against it at least partially. In particular, it can be the only area of ​​the sealing element that directly contacts or bears against the component, at least when the component has not shifted relative to its intended position. This contact can be maintained, in particular, continuously during operation of the electrochemical system.

[0028] At least sections of the sealing element's edge surface can optionally also be configured to contact the component, particularly at least selectively, for example, if the component slips within or parallel to the layer plane. However, according to embodiments discussed below, at least in a non-slipped state of the component, a gap can preferably exist between the edge surface and a region of the component opposite the edge surface.

[0029] Using the claimed solution, at least a partial volume of the component can be lowered relative to the first outer surface and / or, more generally, to an outer surface of the layer, and / or be flush with it, according to the lowering of the bearing area. Figuratively speaking, the component can thus be embedded in the sealing element, at least section by section and / or at least over a portion of its thickness, particularly when viewed transversely to the layer plane. Consequently, the component can have a generally planar profile and be reliably structurally supported within this plane, including and especially in its edge regions resting in the bearing area.

[0030] By lowering the contact area and integrating the component into or onto it, the risk of the component being subjected to excessive local stress and / or deformation, particularly during compression of the electrochemical system and / or operation at high fluid pressures, at least in a peripheral area of ​​the flow field, can be limited. This improves the fluid tightness of the contact between the sealing element and the component. Furthermore, the risk of excessive buckling or tearing of this component, or of any other components supported by it, such as a MEA, can be reduced. The resulting improved resistance to damage can ensure reliable operation, especially of any other components.

[0031] Such an additional component preferably rests only on or against the first-mentioned component, which is accommodated in the support area. It is preferably not rigidly connected to this component and / or to the frame-shaped layer, in particular not by a material bond or by means of mechanical fasteners. According to one variant, however, the additional component also rests on the layer or at least partially overlaps it. In particular, it can extend beyond the support area and the sealing element, for example, project laterally, and thus be adjacent to a region of the layer near the sealing element. The first-mentioned component, which is accommodated in the support area, preferably does not extend beyond the support area. In general, the support area can serve as a kind of abutment for only one half-cell of the electrochemical system.

[0032] Additionally or alternatively, lowering the support area can define a secure positioning and / or a secure fit of the component within or parallel to the layer plane. For example, this can limit any potential slippage of the components within or parallel to the layer plane. Secure positioning of the component, particularly during assembly and / or pressing of the electrochemical system, ensures reliable operation of the system.

[0033] According to one embodiment, the bearing area, and in particular at least its bearing surface, is recessed by at least the thickness of the component + / - 0.1 mm, i.e., by a range of at most 0.1 mm more than the thickness and at least 0.1 mm less than the thickness, relative to the adjacent first area of ​​the sealing element and / or relative to a neighboring surface of the layer. The extent of the recession can additionally or alternatively correspond to the thickness of the component in its installed state, and according to the following embodiments, such a recession can also be present in an unloaded and / or uninstalled state of the sealing element.

[0034] The degree of lowering can correspond to the extent and, in particular, the height of the aforementioned edge surface of the sealing element transversely to the plane of the layer, or to the thickness of the component in the assembled state. It has been shown that the aforementioned technical effects of the invention can be reliably achieved with such a degree of lowering. Furthermore, this allows for uniform and, in particular, unobstructed support of a further component, which is supported by the component received in the bearing area, but may extend beyond it and also beyond the sealing element.

[0035] According to one embodiment, the support area, and in particular at least its support surface, when viewed transversely to the plane of the layer, does not protrude from the layer itself. In other words, the support area, and in particular at least its support surface, can extend along the same area along an axis transverse to the plane of the layer as the layer itself. Such an axis can correspond to a thickness or height axis of the layer. Such a positioning of the support surface can enable a preferred lowering and / or partial countersinking of the component into and / or relative to the layer.

[0036] According to one embodiment, the support area projects completely into the recess. In other words, the corresponding recessed portion of the outer edge extends completely into the recess and / or is entirely within a free volume defined by the recess. In particular, this can correspond to a complete overlap of the support area with the plan view of the recess. Accordingly, the support area can be spaced from the inner edge of the recess, for example, at least by the first area relative to which the support area is recessed. This can simplify the manufacturing of the support area.

[0037] According to one embodiment, the contact area has a width, measured along a width axis running transversely to the inner edge, of at least 0.2 mm in at least some sections. In other words, the width can be measured within or parallel to the plane of contact. The width can be constant or variable along the contact area. This minimum width ensures reliable support of the component by the contact area.

[0038] According to one embodiment, the bearing area is designed to be recessed relative to an adjacent surface of the bearing even when the sealing assembly is unloaded. Under appropriate load, the degree of recession can optionally be increased further. This recessing, even when unloaded, ensures a reliable, recessed fit of the component within and / or relative to the bearing.

[0039] According to one embodiment, at least in the unloaded state, the sealing arrangement protrudes at least partially from an adjacent surface of the layer, particularly when viewed transversely to the layer plane. These protruding areas can, for example, comprise or form a sealing lip that can be brought into contact with a component of the electrochemical system opposite it for the purpose of fluidic sealing. In this way, the sealing arrangement can reliably provide both its sealing function and its support and / or positioning function with respect to the component bearing in the contact area.

[0040] According to a further embodiment, the sealing element, and in particular at least one sealing lip thereof, extends along the entire inner edge of the recess. This ensures a reliable fluidic sealing function.

[0041] According to a further embodiment, the contact area comprises the previously mentioned contact surface, which optionally extends along the inner edge. The contact surface can be interrupted, at least in sections, along the inner edge. The interrupted sections can enable targeted fluid flow and, in particular, can be part of a fluid guidance structure described below.

[0042] According to a further embodiment, the sealing arrangement comprises at least one elastomeric fluid guide structure with a plurality of fluid passages, hereinafter also referred to as fluid channels, for guiding a fluid to or from the recess. In particular, the fluid guide structure can be formed integrally with the sealing element. The fluid passages can be formed as recesses, such as grooves or slots, in the fluid guide structure. The recesses can extend between raised areas of the fluid guide structure. Their open sides can abut and / or be bounded by an adjacent separator plate. Alternatively, the fluid passages can be completely surrounded by the elastomeric material of the fluid guide structure in a direction perpendicular to the flow direction of the fluid.This can be equated with the fluid passages being designed as a type of bore or channel with a closed cross-section and / or closed circumference within the sealing element.

[0043] In some embodiments, the recess and at least one through-opening of the frame-shaped layer are fluidly connected by the elastomeric fluid guidance structure. In particular, the recess and the through-opening can be structurally and / or spatially separated from each other solely by the elastomeric fluid guidance structure, but not, for example, by a metallic material of the layer itself. Thus, only the material of the fluid guidance structure can run between the recess and the through-opening, without any material of the layer being present there. This can represent a structural and / or production-related simplification.

[0044] The invention also relates to an arrangement for an electrochemical system, comprising: • a sealing arrangement according to any of the aspects disclosed here, and • a separator plate which rests against a second outer surface of the sealing element of the sealing arrangement, which in particular is opposite or facing away from the first outer surface, and which in the area of ​​the recess and / or opposite it comprises a flow field, or in other words: an active area or a flow field, with a plurality of depressions, such as channels, and elevations arranged between the depressions, such as ribs, where: • the bearing area of ​​the sealing element is spaced, at least sectionally and at least in the loaded state of the sealing arrangement, no more than an unsupported maximum permissible distance between two bearing points of the component on elevations in the flow field from a nearest element of the flow field; and / or • The bearing surface of the sealing element, viewed orthogonally to the plane of the layer, lies at a substantially common height with the raised sections / ribs and, in particular, with the rib crests thereof, at least in the installed state. A substantially common height can be understood as a common height achievable within the scope of standard manufacturing tolerances. For example, any height deviations must not exceed 0.1 mm or 0.05 mm; and / or • the bearing area of ​​the sealing element is at least sectionally and at least in the loaded state of the sealing arrangement spaced no more than twice the channel width and in particular no more than one channel width from a nearest element of the flow field and / or no more than an average distance - or no more than one and a half times this average distance - between any two immediately adjacent elevations in the flow field.

[0045] By appropriately designing the bearing area according to the aforementioned variants relative to the adjacent elements of the flow field, and in particular the aforementioned structural elements in the form of depressions / channels and ridges / ribs, reliable structural support for the component can be achieved. The arrangement can furthermore include the component, in particular in the form of a PTL, and optionally also a further adjacent component, in particular in the form of an MEA. Within the scope of this disclosure, the use of a slash “ / ” between two features can indicate an “and / or” relationship between these features.

[0046] According to a further variant of the arrangement, which may be provided in addition to or as an alternative to any of the above variants, the distance between the component and an opposite area of ​​the sealing element, viewed parallel to the plane of the layer, may not exceed 2 mm and, in particular, may not exceed 1 mm. The opposite area may, for example, comprise a previously discussed edge section of the bearing area and / or the sealing element. Such a distance can also ensure reliable component retention, taking into account manufacturing tolerances and / or limiting multiple fits. On the other hand, limiting the distance to the aforementioned maximum dimensions can prevent any potential slippage of the component, particularly during assembly and / or clamping of the electrochemical system.

[0047] According to a further embodiment of the arrangement, the additional component of the electrochemical system is a porous transport layer, PTL. This preferably rests against the flow field of the separator plate and the bearing area of ​​the sealing element, so that it receives structural support from both the separator plate and the sealing element.

[0048] The invention also relates to an electrochemical system comprising a plurality of arrangements according to any of the aspects disclosed herein.

[0049] 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 an exploded view of a single cell of an electrolyzer according to the prior art; Fig. 2 a perspective view of a separator plate on which a sealing arrangement according to an embodiment of the invention can be provided; Fig. 3 A partial view as a sectional view of an arrangement according to an embodiment of the invention, comprising a separator plate, which is in principle analogous to Fig. 3 is designed, and a sealing arrangement attached to it; Fig. 4 a partial view as a sectional view of the sealing arrangement from Fig. 3 with adjacent PTL; Fig. 5 a detailed view of the arrangement Fig. 4.

[0050] Fig. Figure 1 shows an exploded view of an electrochemical single cell 9, wherein the single cell 9 is part of an electrochemical system in the form of an electrolyzer. Electrolyzers typically comprise a plurality of such single cells 9 in a stacked arrangement. The single cell 9 comprises two separator plates 1 and 2, two cell frames 142 and 144, a sealing layer 145, and a membrane electrode assembly 140 with media diffusion structures 141 and 143. The media diffusion structure 143 comprises, for example, layers of carbon fleece, while the media diffusion structure 141 comprises metal, e.g., titanium. The separator plate 1 is, for example, arranged on the anode side of the single cell 9. In the illustrated embodiment, the separator plate 2 is arranged on the cathode side of the single cell 9. The individual layers shown are pressed together to form a compact single cell 9.Each layer has fluid feedthroughs 146, 147, 150 arranged in alignment above one another for the introduction and removal of water, oxygen and hydrogen, as well as positioning holes 148.

[0051] A flow field of the separator plate 2 is defined by projecting cell frame 144 onto separator plate 2. A flow field 3 of the separator plate 1 is defined by projecting cell frame 142 onto separator plate 1. The projections are preferably orthogonal to a plane within which cell frames 142 and 144 extend.

[0052] The cell frame 142 has distribution channels (not shown) for distributing the introduced water. The through-openings 146 and 147 are in fluid communication with the flow field 3, so that a medium can be directed from through-opening 146 to flow field 3 or from flow field 3 to through-opening 147. When an electrical potential is applied, hydrogen (or oxygen) can be produced from the supplied water in the electrolyzer.

[0053] This can be discharged through the distribution channels 149 in the cell frame 144. The cell frames 142 and 144 represent examples of frame-shaped layers. Subsequently, the hydrogen can leave the cell through the through-openings 150. While the in Fig. Although the separator plates 1, 2 shown in Figure 1 have a round outer contour, other shapes are also possible. For example, the separator plates 1, 2 can have a rectangular outer contour, see Figure 1. Fig. 2.

[0054] As mentioned, the pressure difference between the environment and the interior of the electrochemical cell 9 can exceed 20 bar. Often, the pressure on the product side, for example, the hydrogen side, is up to 40 bar, while the pressure on the reactant side, for example, the water side, is only up to 2 bar. Therefore, sealing structures are provided to seal the individual areas from one another. For example, elastomer seals of sealing layer 145 are used, which are arranged around the areas to be sealed, e.g., flow field 3 or through-openings 146, 147, 150.

[0055] In Fig. Figure 2 shows a schematic simplified view of a separator plate 10, which can be used in an arrangement 100 according to the invention, as explained with reference to the following figures. In principle, the separator plate 10 and the arrangement 100 are to be used in a Fig. 1 analogously constructed electrochemical cell can be used, with the exception of the deviation explained below concerning any cell frames and sealing layers. However, the separator plate 10 has one of the features described in Fig. The separator plates 1 and 2 shown in 1 have a different, but not restrictive, rectangular shape.

[0056] The separator plate 10 comprises a metallic layer, which consists, for example, at least predominantly or entirely of titanium or stainless steel or alloys thereof. The metallic layer 10 can have a thickness of at least 0.1 mm and / or at most 0.8 mm. The separator plate 10 has a flow field 3, which is designed to distribute the water supplied from the through-openings 4 as evenly as possible. For this purpose, channel structures 6 are optionally provided in the flow field 3. The individual channels / recesses 16 of the channel structures 6 are separated from one another by ridges / protrusions 18, see the following. Fig. 3. The flux field 3 lies in an electrochemically active area (active area) and significantly defines its spatial extent and, in particular, its base area.

[0057] The through-openings 5 ​​are designed for the removal of hydrogen, wherein on the side of the separator plate 10 shown, the through-openings 5 ​​are separated by a design explained below and in Fig. 2 are surrounded by elastomer seals not shown. The elastomer seal 26 (shown in Fig. 3) ensures that, on the one hand, water and ambient air cannot enter the through-openings 5 ​​and, on the other hand, that hydrogen cannot escape. Optionally, positioning holes 8 for receiving centering pins are also shown so that the separator plate 10 can be aligned or centered.

[0058] In comparison and in contrast to separator plates 1, 2 of the Fig. 1. It is noticeable that the separator plate 10 is made of Fig. The area between flow field 3 and the passage opening 4, 5 is essentially flat, i.e., designed as a level surface. Outside flow field 3 and apart from any openings 4, 5, 8, the separator plate 10 is designed as a flat, level plate, particularly everywhere outside the aforementioned areas 3, 4, 5, 8. The flat area 11 of the separator plate 10 comprises, for example, a first sub-area 12 and a second sub-area 13. The first flat sub-area 12 borders the passage opening 4, 5 and completely surrounds it. The second flat sub-area 13 borders flow field 3 and completely surrounds it. In the aforementioned areas 11, 12, 13, the separator plate 10 has no sealing elements or other raised or recessed features. Thus, these areas 11, 12, 13 are free of sealing beads, elastomer seals, elastomer ridges and / or recesses for receiving sealing elements.

[0059] The separator plate 10 has two opposite sides 17, 19, wherein in the Fig. 2 Only the first side 17, which can also be referred to as the front, is visible, while the second side 19, which can also be referred to as the back of the separator plate 10, is hidden from view. Due to the absence of sealing elements in the separator plate 10, both sides 17, 19 of the separator plate 10 can be designed identically, so that the separator plate 10 has a rotational symmetry axis that runs through the plane of the separator plate 10 and parallel to the plane of the separator plate 10. A rotation by 180° about this rotational symmetry axis results in the same arrangement of the separator plate 10, except, at most, that the channels 6 in the flow field 3 are oriented in the opposite direction. In the illustrated embodiment, the separator plate 10 is single-layered and made of titanium.

[0060] The fluidic sealing of the flow field 3 and the fluidic sealing of the fluid passages 4, 5 are realized by a sealing arrangement 22 separate from the separator plate 10, which is described below with reference to Fig. 3 is described. The in Fig. The 3 described elastomeric sealing elements 26, 28 are installed in the flat sections 12, 13 of the separator plate 10.

[0061] Fig. Figure 3 shows a partial section of an arrangement 100 according to an embodiment of the invention. The arrangement 100 comprises a separator plate 10 of the type of Fig. 2 and is part of an electrochemical system 101, which is otherwise not shown in detail. The latter is, for example, an electrolyzer. Any and non-limiting differences from the schematic representation from Fig. 2 concerns, for example, the exact contour lines of the passage openings 4, 5.

[0062] Furthermore, the order includes 100 from Fig. 3 a sealing arrangement 22 with a frame-shaped layer 24 arranged substantially congruently to the separator plate 10 and a plurality of sealing elements 26, 28. The in Fig. The partial section shown in Figure 3 comprises an upper left corner area of ​​the separator plate 10. Fig. 2. This corner area encompasses a portion of each of the through-openings 4 and 5, as well as one of the centering openings 8. Likewise, the depicted corner area of ​​the separator plate 10 encompasses a portion of the flow field 3, whereby one can see in Fig. 3 recognizes in detail the channels 16 and bridges 18 formed there.

[0063] It goes without saying that the excerpt from Fig. Figure 3 is representative of the other areas of the arrangement 100 not shown. That is, the arrangement 100 and in particular its sealing arrangement 22 and separator plate 10 are designed analogously and according to the details explained below outside the illustrated sub-area.

[0064] In the illustration shown, the separator plate 10 is arranged below the frame-shaped layer 24. The layer 24 comprises recessed areas 27, 23, 30, which are positioned opposite, or in other words, overlapping with, each of the through-openings 4, 5 and the optional centering openings 8 of the separator plate 10. Another recessed area 33 is arranged opposite the flow field 3 of the separator plate 10 and surrounds it, and thus the active area, in a frame-like manner. Consequently, the through-openings 4, 5, the flow field 3, and the centering opening 8 are not, or at most only partially, obscured by the layer 24. In the example shown, the recessed areas 30, 33 are part of a continuous, large-area recess 35 within the layer 24. However, this is not mandatory.It could also be that a material section of layer 24 structurally separates the recessed areas 30 and 33 from one another, so that these could be formed as separate recesses. As will be further clarified below, in the example shown, the recessed areas 30 and 33 are structurally and fluidically separated from one another by a separating section 38 of the density element 28 described below.

[0065] The recess 35 includes an inner edge 36 which surrounds the recess 35 and / or defines an edge region and / or a circumferential contour thereof. The inner edge 36 may face a geometric center of the recess 35, which is not shown separately.

[0066] The sealing arrangement 22 comprises an elastomeric sealing element 26 circumferentially surrounding a respective through-opening 5. However, this disclosure specifically considers a further elastomeric sealing element 28, which extends along the inner edge 36 of the recess 35 with an inner edge region 29, which could also be referred to as the first edge region, and is, in particular, injection-molded onto this inner edge 36. The inner edge region 29 is, for example, located inside the inner edge 36 from the perspective of and relative to the inner edge 36. The sealing element 28 also has an outer edge region 31, which could also be referred to as the second edge region and is, for example, located outside the inner edge 36 of the recess 35, in particular further outside than the inner edge region 29. The outer edge region 31 surrounds the flow field 3 in a frame-like manner, for example, when viewed in a top view according to the viewing angle arrow D and / or when viewed in a projection along this viewing angle arrow D. Fig. 3 is a first outer surface 34 of the sealing element 28 facing the viewer or, in other words, lying on top.

[0067] The sealing element 28 in the example shown is designed such that it also surrounds and fluidically seals each through-opening 4 of the separator plate 10. However, fluid passage through the through-opening 4 in a direction transverse to the layer plane 24 is still permitted.

[0068] The sealing element 28 has a bearing area 44 for a PTL 46 in its outer edge region 31 which surrounds the flow field 3 (see Fig. 4) as a further component of the electrolyzer adjacent to the flow field 3. The extension of this PTL 46 and its inclusion in the support area 44 will become clear from the following discussion. Fig. 4.

[0069] The outer edge region 31 and / or the bearing area 44 of the sealing element 28 has two longitudinal sides 40 extending along a flow axis S of the flow field 3, one of which is sectionally in Fig. 3 is recognizable. The flow direction S is defined by the longitudinal extension of the channels 16 and webs 18. Furthermore, the support area 44 has two transverse sides 42 extending perpendicular to the flow axis S, one of which is sectionally in Fig. 3 is recognizable.

[0070] The support area 44 has a support surface 48 on each of its longitudinal side 40 and transverse side 42 for contacting and resting against the PTL 46, see. Fig. 4. The width B1 of the bearing surface 48, and thus of the bearing area 44, measured perpendicular to the inner edge 36 and / or in the plane of the layer, can assume any value disclosed herein. This width can be constant or variable along the bearing surface 48 and can be measured along the width axis B shown.

[0071] In the example shown, the support surface 48 is continuous along the longitudinal sides 40. Along the transverse sides 42, it is interrupted in sections, so that one can also speak of several support surface sections or segments there. The support surface 48 (or its individual support surface sections) forms a flat contact surface for the PTL 46, see figure. Fig. 4.

[0072] The print run of 44 is different from one in Fig. The upper outer surface of layer 24 and the first outer surface 34 of the sealing element 28 are recessed. More precisely, they are recessed relative to a first area 50 of the sealing element 28, which is directly adjacent to the bearing area 44 and, in particular, its bearing surface 48. Specifically, this area borders the first outer surface 34 of the sealing element 28 along a plane of layer 24 (layer plane) and / or along the first outer surface 34. A layer plane can be understood, for example, as a median plane of layer 24 or a plane parallel to the outer surface of layer 24 facing the observer. In the example shown, the first area 50 runs essentially parallel to a layer plane of layer 24 and to the bearing surface 48.

[0073] The height difference between the first area 50 and the support area 44 is orthogonal to the plane 24. This height difference is bridged by a boundary surface 52, which in the example shown is orthogonal to the first area 50 and to the support surface 48.

[0074] The sealing element 28 also includes a sealing lip 54 extending along its entire inner edge 36. This lip protrudes both from the first area 50 and from the outer surface of layer 24 facing the viewer when not installed, again perpendicular to the plane of the layer. Consequently, the sealing lip 54 forms a region of the sealing element 28 that protrudes from layer 24. The sealing lip 54 serves to fluidically seal the area surrounding it, and thus in particular the flow field 3, when in contact with an opposing component (not shown), for example, the MEA or its edge reinforcement.

[0075] In the example shown, a fluid guidance structure 56 is also formed in the sealing element 28. In this example, the fluid guidance structure 56 is integrally formed into the sealing element 28 and is thus also defined and bounded by its elastomeric material. It comprises several fluid passages in the form of fluid channels 58, of which only one open end section is visible. The fluid channels 58 extend parallel to the depicted flow axis S and between the depicted end of the flow field 3 and one of the passage openings 4. They are described as Fig. 3 downward-facing grooves or slots are formed, with a [missing information] on their underside. Fig. The visible upper surface 17 of the separator plate 10 rests against the separator plate 10, thus closing off the lower surfaces. The open end sections of the fluid channels 58 shown are each opposite one of the channels 16 of the flow field 3. The fluid channels 58 each form a fluidic connection between the flow field 3 and at least one of the through-openings 4.

[0076] Fig. Figure 4 shows the arrangement of 100. Fig. Figure 3 shows the PTL 46, which is located in the support area 44 of the sealing element 28. It can be seen that an underside of the PTL 46 facing away from the viewer, and more precisely an outer circumferential edge region thereof, rests on the support surface 48 of the support area 44. This also applies to the support surface 48 along the transverse side 42 of the support area 44, which is covered by the PTL 46. Furthermore, it can be seen that the underside of the PTL 46 also rests against the webs 18 of the flow field 3.

[0077] Fig. Figure 5 shows an enlarged section of the illustration from Fig. 4 and more precisely the installation of the PTL 46 in the support area 44. The partial section shown comprises the area near the reference numeral 48 from Fig. 4.

[0078] The arrangement of the PTL 46 can again be seen with its underside against the contact surface 48. Furthermore, it can be seen that between, for example, the outermost end of the outer edge region 31 of the sealing element 28, viewed along the width axis B, and an adjacent web flank, there is a distance D2 measured parallel to the layer plane. In this example in Fig. In Figure 5, the flow field 3 is formed by channels 16 separated by webs 18. However, other channel-forming structures besides ridges 18 are also conceivable. In any case, the distance D2 from the nearest element 18 of the flow field 3 is chosen such that it is not greater than the maximum permissible unsupported distance B2 between two support points 15 of component 46 on ridges / webs 18 in the flow field 3. For example, this permissible distance B2 is not greater than a single channel width or one and a half times the channel width, measured, for example, at half the height of the web flanks bounding a channel 16. A maximum or average channel width in the flow field can, for example, be considered.

[0079] Alternatively or additionally, the permissible distance B2 may not exceed an average distance between any two immediately adjacent elevations / footbridges 18 in the river field 3 or may not exceed one and a half times this average distance.

[0080] Alternatively or additionally, the permissible distance B2 can be a characteristic value of component 46 that is familiar to those skilled in the art. For example, the permissible distance B2 can depend on the thickness of component 46. Exceeding this distance B2 can lead to insufficient support and consequently to an unacceptably high deformation of component 46.

[0081] As an example, this distance D2 is measured between the support surface 48 of the PTL 46 and an outermost support point 15 of the elevations / bridges 18 of the flow field 3. Advantageously, this distance encompasses less than a uniform channel width within the flow field 3. This accordingly limits the extent of the area of ​​the PTL 46 extending along the distance D2 in which it is not supported by either the support surface 48 or one of the bridges 18.

[0082] It is also shown that a gap, preferably circumferential to the PTL 46, is formed between the PTL 46 and the edge surface 52 of the sealing element 28. This gap, measured parallel to the plane of the layers, has a width or gap width D1 of, for example, less than 2 mm or less than 1 mm. Advantageously, the distance D1 is no more than twice the material thickness of the MEA, i.e., no more than approximately 0.5 mm. The edge surface 52, viewed parallel to the plane of the layers, forms a region of the sealing element 28 opposite the PTL 46.

[0083] Furthermore, a height axis H running orthogonally to the plane of the plane is shown, along which the height offset V between the support surface 48 and the first area 50 exists. The height offset V advantageously corresponds to a thickness of the PTL 46. A in Fig. 4 Top side of the PTL 46 and the first area 50 as well as optionally the in Fig.The top surfaces of layer 24 are thus aligned with each other. In other words, they are at the same height. This ensures stepless support for another component (not shown) adjacent to the PTL 46, such as an MEA. Optionally, this additional component can extend laterally further over the sealing element 28 and, for example, be located opposite the outer surface of layer 24. 101 electrochemical system 1 Separator plate in the state of the art 2 Separator plate in the state of the art 3 Flow field of the separator plate 4 Water supply and water and oxygen drainage / passage openings 5 hydrogen vents / passage openings 8 positioning holes 9 electrochemical single cell 10 separator plates 11 flat areas 12 first sub-area of ​​11, surrounding the passage openings 4, 5 and 8 13 second sub-area of ​​11 surrounding the river field 3 15 PTL support points on bridges / elevations 18 16 depressions / channels of the flowfield of 10 17 one side / front / top of 10 18 elevations / footbridges of the flowfield of 10 19 second page of 10 22 Sealing arrangement 23 Recess of 24 in the area of ​​8 24 frame-shaped arrangement of 22 26 elastomeric sealing element 27 Recess of 24 in the area of ​​5 28 elastomeric sealing element 29 Inner edge area of ​​the elastomeric sealing element 28 30 recess of 24 in the area of ​​4 31 Outer edge area of ​​the elastomeric sealing element 33 recessed area 34 first outer surface of the elastomeric sealing element 35 Recess of the cell frame 36 Inner edge of the sealing arrangement 38 elastomeric fluid guidance structure between 30 and 33 40 Long sides of the sealing element 28 42 transverse sides of the sealing element 28 44 Contact area of ​​the sealing element 28 46 components, e.g., PTL 48 contact area of ​​44 for 46 50 to 44 adjacent area of ​​the sealing element 28 52 Edge surface of the elastomeric sealing element 28 56 Fluid guidance structure (elastomeric distribution area) 58 fluid feedthroughs in fluid guidance structure 56 and more precisely in the elastomeric distribution area B Width axis perpendicular to the inner edge 36 B1 Width of the support areas B2 permissible distance

Claims

[1] Sealing arrangement (22) for an electrochemical system (101) which, when installed in the electrochemical system (101), can withstand loads perpendicular to a layer plane, wherein the sealing arrangement (22) comprises: • a frame-shaped layer (24) with a recess (35), wherein the recess (35) is configured to surround an electrochemically active region of the electrochemical system (101) in a frame-shaped manner, and wherein the recess (35) has an inner edge (36), as well as • an elastomeric sealing element (28) which rests with an inner edge region (29) on the inner edge (36) of the recess (35) and projects into the recess (35) with an outer edge region (31), wherein the outer edge region (31) comprises at least on a first outer side (34) at least sectionally a bearing area (44) for a component (46) of the electrochemical system, which is lowered relative to an adjacent first area (50) of the sealing element (28). [2] Sealing arrangement (22) according to the preceding claim, wherein the bearing area (44) is lowered by the thickness of the component (46) in the installed state relative to the adjacent first area (50) of the sealing element (28) and / or relative to an adjacent surface of the layer (24). [3] Sealing arrangement (22) according to one of the preceding claims, wherein the bearing area (44) projects completely into the recess (35). [4] Sealing arrangement (22) according to one of the preceding claims, wherein the bearing area (44) has a width (B1) measured along a width axis (B) extending transversely to the inner edge of at least 0.2 mm in at least sections. [5] Sealing arrangement (22) according to one of the preceding claims, wherein the support area (44) is arranged to be lowered relative to an adjacent surface of the layer (24) even in the unloaded state of the sealing arrangement (22). [6] Sealing arrangement (22) according to one of the preceding claims, wherein at least in the unloaded state the sealing arrangement (22) protrudes at least partially from an adjacent surface of the layer (24). [7] Sealing arrangement (22) according to one of the preceding claims, wherein the sealing element (28) extends along the entire inner edge (36). [8] Sealing arrangement (22) according to claim 7, wherein the support area (44) comprises a support surface (48) for the component (46), wherein the support surface (48) is interrupted at least sectionally along the inner edge (36) and / or the outer edge area (31). [9] Sealing arrangement (22) according to one of the preceding claims, comprising at least one elastomeric fluid guidance structure (56) with a plurality of fluid passages (58) for guiding a fluid from or to the recess. [10] Sealing arrangement (22) according to claim 9, wherein the fluid guidance structure (56) is integrally formed with the sealing element (28). [11] Arrangement (100) for an electrochemical system, comprising: • a sealing arrangement (22) according to one of the preceding claims, and • a separator plate (10) which abuts a second outer surface of the sealing element (28) of the sealing arrangement (22) and which in the area of ​​the recess (35) comprises a flow field (3) with a plurality of depressions (16) and elevations (18) arranged between the depressions (16), wherein: • the bearing area (48) of the sealing element (28) is spaced at least sectionally and at least in the loaded state of the sealing arrangement (22) by no more than an unsupported maximum permissible distance (B2) between two bearing points of the component (46) on protrusions (18) in the flow field (3) from a nearest element (18) of the flow field (3) (D2); and / or • the bearing area (48) of the sealing element (28), viewed orthogonally to the plane of the layer, lies at a substantially common height with the elevations (18) and in particular with the crests thereof; and / or • when viewed parallel to the plane of the layer, the distance (D1) of the component (46) from an opposite area of ​​the sealing element (28) is no more than 2 mm and in particular no more than 1 mm. [12] Arrangement (100) according to claim 11, wherein the component (46) of the electrochemical system (101) is a porous transport layer, PTL, which can be brought into contact with the flow field (3) of the separator plate (10) and the bearing area (48) of the sealing element (28). [13] Electrochemical system (101) comprising a plurality of arrangements (100) according to one of claims 11 and 12.

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