Separator plate for an electrochemical system and associated electrochemical system comprising a variety of separator plates

Abstract

Separator plate for an electrochemical system, with a first single plate (2a), - wherein the first single plate (2a) has embossed webs (32) on a first side with channel (30) sectionally delimiting web flanks (33), wherein the channels (30) are designed to guide a first fluid, wherein the first single plate (2a) has first transition areas (I) with a first embossing radius between channel bottoms (301) and the adjacent web flanks (33); - wherein on a second side of the single plate (2a) the channels (30) form raised areas (34) and the webs (32) form grooves (36) for guiding a second fluid, wherein the first single plate (2a) has second transition areas (II) with a second embossing radius between groove bottoms and adjacent raised flanks forming the grooves; characterized in that the first single plate (2a) forms a plurality of stiffening structures (60) arranged in the first and / or second transition areas, wherein the stiffening structures (60) form local bulges, wherein the bulges have a radius larger than the respective embossing radius and wherein the bulges extend over a height smaller than a web height.

Description

[0001] The disclosure relates to a separator plate for an electrochemical system and to an electrochemical system comprising at least one such separator plate.

[0002] Known electrochemical systems, such as fuel cell systems or electrochemical compressor systems, redox flow batteries, and electrolyzers, typically comprise a plurality of separator plates arranged in a stack, so that each two adjacent separator plates enclose an electrochemical cell. The separator plates often comprise two individual plates each, which are connected to each other along their rear sides facing away from the electrochemical cells. In electrolyzers, for example, the separator plates can also comprise only a single plate. The separator plates can serve, for example, to electrically contact the electrodes of the individual electrochemical cells (e.g., fuel cells) and / or to electrically connect adjacent cells (series connection of the cells).

[0003] The individual plates of the separator plates can have channel structures for supplying the cells with one or more media and / or for transporting media away. In the case of fuel cells, the media can be, for example, fuels (e.g., hydrogen or methanol), reaction gases (e.g., air or oxygen), or a coolant as supplied media, and reaction products and heated coolant as removed media. Furthermore, the separator plates can be used to conduct the waste heat generated in the electrochemical cell, such as that generated during the conversion of electrical or chemical energy in a fuel cell, and can be designed to seal the various media or cooling channels from one another and / or from the outside. In fuel cells, the reaction media, i.e.,Fuel and reaction gases are guided, while the coolant is guided between the individual plates. The bipolar plates usually each have at least one or more through-openings. The media and / or the reaction products can be guided through the through-openings to the electrochemical cells defined by adjacent separator plates of the stack or into the cavity formed by the individual plates of the separator plate, or can be discharged from the cells or from the cavity. The electrochemical cells, in particular of a fuel cell, can each comprise, for example, a membrane electrode assembly (MEA), each with a polymer electrolyte membrane (PEM) and electrodes. The MEA can also have one or more gas diffusion layers (GDL), which are usually oriented towards the separator plates, in particular the separator plates of fuel cell systems, and can, for example,are formed as a carbon fleece. In an exemplary fuel cell, hydrogen supplied on the anode side is typically converted to water with oxygen supplied on the cathode side. Protons produced during hydrogen oxidation pass from the anode side through the MEA to the cathode, where they react with the oxygen and electrons to form water. The fuel cell membrane is electrically insulating and prevents an electrical short circuit between the anode and cathode. The electrons are separately supplied from the anode to the cathode, thus harnessing the electrical current.

[0004] The individual plates of the separator plates are typically embossed to form the web and channel structures. Electrochemical systems are subject to high demands in applications involving electrochemical systems, particularly in the automotive and aerospace sectors. During the embossing process, springback leads to bulging effects and thus to shape deviations. A large number of embossed webs and channels can exacerbate this adverse effect.

[0005] The object of the invention is therefore to propose an improved, in particular stiffened, separator plate and / or an improved electrochemical system comprising at least one such separator plate, in particular to the effect that bulging effects are reduced.

[0006] This object is achieved according to the invention by the separator plate according to claim 1 and / or an electrochemical system according to the independent claim. Further developments are the subject of the dependent claims and the following description.

[0007] The proposed separator plate for an electrochemical system comprises a first single plate.

[0008] The first individual plate has embossed webs on a first side with web flanks that partially delimit channels. In particular, the web flanks can form the channels together with channel bottoms formed between two web flanks. The channels are designed to conduct a first fluid. The first individual plate has first transition areas with a first embossed radius between the channel bottoms and the adjacent web flanks.

[0009] On a second side of the individual plate, the channels form raised portions, and the webs form grooves for guiding a second fluid. The first individual plate has second transition areas with a second embossing radius between the groove bottoms and adjacent raised flanks forming the grooves.

[0010] The first individual plate forms a plurality of stiffening structures arranged in the first and / or second transition regions, wherein the stiffening structures form local bulges, wherein the bulges have a radius that is larger than the respective stamping radius. Furthermore, the bulges can extend over a height that is less than a web height. In particular, a maximum height of the bulges can therefore be less than a web height. A height of the bulges can, for example, be measured along a direction orthogonal to the flat surface plane, originating from the channel floor.

[0011] The stiffening structures can reduce bulging effects.

[0012] The radii of one or more of the curvatures can approach infinity, especially when the curvatures are formed as inclined planes. The radii can be observed particularly in the cross-section of the channels and grooves, i.e., perpendicular to the macroscopic channel extension.

[0013] A flat surface plane can run through the channel bottoms. The web height can be defined as the maximum height of the web measured orthogonally to the flat surface plane and starting from the flat surface plane. It can also include the single material thickness, so that measurements are preferably taken from the same surface of the material in each case.

[0014] At least some of the stiffening structures can be curved into the channel in the first transition region and protrude into the channel. Additionally or alternatively, at least some of the stiffening structures can be curved into the groove in the second transition region and protrude into the groove.

[0015] The stiffening structures can have a maximum elongated extension along the elongated channel extension or groove extension that is greater than 0.1 times the web height, preferably greater than 0.15 times the web height, particularly preferably greater than 0.2 times the web height. The stiffening structures can have a maximum elongated extension along the elongated channel extension or groove extension that is less than the web height, preferably less than 2.5 times the web height, particularly preferably less than 1.5 times the web height.

[0016] The stiffening structures can have a maximum elongated extension along the elongated channel extension or groove extension that is greater than 120 µm, preferably greater than 130 µm, particularly preferably greater than 150 µm.

[0017] The stiffening structures may have a maximum elongated extension along the elongated channel extension or groove extension which is less than 3 mm, preferably less than 2 mm, particularly preferably less than 1 mm.

[0018] The stiffening structures can have a maximum lateral extension transverse to the elongated channel extension or groove extension which is greater than 0.2 times the channel width measured at half height in channel sections without local curvatures or, in the case of stiffening structures formed in grooves, is greater than 0.2 times the groove width measured at half height in groove sections without local curvatures, preferably greater than 0.3 times the channel width measured at half height in channel sections without local curvatures or, in the case of stiffening structures formed in grooves, is greater than 0.3 times the groove width measured at half height in groove sections without local curvatures, particularly preferably greater than 0.4 times the channel width measured at half height in channel sections without local curvatures.for stiffening structures formed in grooves, is greater than 0.4 times the groove width measured at half height in groove sections without local bulges.

[0019] The stiffening structures in a channel can have a maximum lateral extent transverse to the elongated channel extent or groove extent which is smaller than the channel width measured at half height in channel sections without local bulges, preferably smaller than 0.9 times the channel width measured at half height in channel sections without local bulges, particularly preferably smaller than 0.8 times the channel width measured at half height in channel sections without local bulges.

[0020] The stiffening structures in a groove can have a maximum lateral extension transverse to the elongated channel extension or groove extension which is smaller than the groove width measured at half height in groove sections without local curvatures, preferably smaller than 0.9 times the groove width measured at half height in groove sections without local curvatures, particularly preferably smaller than 0.8 times the groove width measured at half height in groove sections without local curvatures.

[0021] The stiffening structures can have a maximum extension in the direction of the web height, ie in particular in a direction orthogonal to the plane of the flat surface, which is a maximum of 95%, preferably a maximum of 90%, particularly preferably a maximum of 80% of the web height.

[0022] The web flank having the stiffening structure can be inclined by a maximum of 55°, preferably a maximum of 50°, in particular a maximum of 45° to the plate plane in the region of a greatest curvature of the stiffening structure.

[0023] The above-mentioned dimensions or ratios of the stiffening structures can be advantageous, for example, on the one hand to not influence or at least minimally or even positively influence or redirect the flow properties of the fluid to be conducted through the channels or grooves and on the other hand to stiffen the separator plate.

[0024] The stiffening structures can be arranged in a plurality of channels and / or a plurality of grooves.

[0025] The stiffening structures can originate in the elongated channel course from a first and / or a second web flank delimiting the respective channel and / or can originate in the elongated groove course alternately from a first and / or a second raised flank delimiting the respective groove.

[0026] The stiffening structures can be arranged only in channels or only in grooves. However, they can also be arranged in both channels and grooves.

[0027] The stiffening structures of a channel in the direction of channel extension can be arranged offset from stiffening structures of an adjacent groove.

[0028] The separator plate can have more stiffening structures in the central regions of the separator plate in the longitudinal and / or transverse direction than in the edge regions of the separator plate. A longitudinal direction can run along the longitudinal extent of the channels and / or grooves, and a transverse direction can run transversely, in particular orthogonally, to the longitudinal extent. The central region can have a greater distance from the edge in the longitudinal and / or transverse direction than an edge region.

[0029] The stiffening structures can be distributed longitudinally and / or transversely across the separator plate. Additionally or alternatively, the stiffening structures can have constant spacing from one another in the longitudinal and / or transverse directions, at least in some areas. Additionally or alternatively, the stiffening structures can have varying spacing from one another in the longitudinal and / or transverse directions, at least in some areas.

[0030] On the one hand, all of the stiffening structures can be essentially identical in terms of their geometry. However, it is also possible for at least two of the stiffening structures to have different geometries. They can therefore differ in terms of their radii, curvature directions, maximum longitudinal and / or lateral extension, and / or inclination of the web flanks.

[0031] The separator plate may have a second individual plate connected to the first individual plate. The second individual plate may be connected to the first individual plate on a second side, facing away from the first side.

[0032] The second individual plate can have embossed webs on a first side of the second individual plate. The webs can have web flanks that partially delimit channels for guiding a third fluid. The second individual plate can have third transition areas with a third embossed radius between the channel bottoms and the adjacent web flanks.

[0033] On a second side of the second individual plate, the channels can form raised portions and the webs can form grooves for guiding the second fluid. The second individual plate can have fourth transition regions with a fourth embossing radius between the groove bottoms and adjacent raised flanks that at least partially delimit the grooves.

[0034] The second individual plate can form a plurality of stiffening structures arranged in the third and / or fourth transition regions. The stiffening structures in the third transition regions can be locally curved into the channel and in the fourth transition regions can be locally curved into the groove. The curvatures can have a radius that is larger than the respective stamping radius. In the direction orthogonal to the plate plane, the curvatures can be smaller than a web height of the second individual plate. The radii of one or some of the curvatures can approach infinity, particularly if the curvatures are formed as inclined planes.

[0035] The stiffening structures of the first individual plate may differ at least in some of their properties from the stiffening structures of the second individual plate.

[0036] The first single plate can be an anode plate and the second single plate can be a cathode plate or vice versa.

[0037] The first and second individual plates can differ, in particular, at least in their web heights. Additionally or alternatively, the first and second individual plates can differ in their web widths. However, both individual plates preferably have the same period length for a pair consisting of a web and a channel. The first and second individual plates can be designed identically, for example, in their shape and / or dimensions and / or arrangement density of stiffening structures. The first and second individual plates can be designed identically entirely or in certain regions.

[0038] At least some of the stiffening structures of the first individual plate can overlap the stiffening structures of the second individual plate in an orthogonal projection onto the second individual plate and / or be arranged offset from them.

[0039] The present disclosure further relates to an electrochemical system comprising at least separator plates according to the above description, preferably comprising a plurality of separator plates according to the above description.

[0040] Examples of the separator plate and the electrochemical system are shown in the figures and are explained in more detail in the following description. They show: Fig. 1 schematically shows in a perspective view an electrochemical system with a plurality of separator plates arranged in a stack; Fig. 2 schematically shows in a perspective view two separator plates of the system according to Fig. 1 with a membrane electrode assembly (MEA) arranged between the separator plates; Fig. 3 schematically shows a section through a plate stack of a system according to the type of system according to Fig. 1; Fig. 4A schematically shows a plan view of a single plate; Fig. 4B which in Fig. 4A shows the single plate schematically as a bending beam; Fig. 5A schematically shows a perspective view of a section of a single plate of a system according to the type of system according to Fig. 1; Fig. 5B schematically shows a plan view of the Fig. section shown in Figure 5A; Fig. 5C schematically shows a section through the Fig. 5A shown section along the Fig. 5B shown section line BB; Fig. 5D schematically shows a section through the Fig. 5A shown section along the Fig. 5B shown section line CC; Fig. 6A schematically shows a perspective view of a section of a single plate of a system according to the type of system according to Fig. 1; Fig. 6B schematically shows a plan view of the Fig. 6A shown section; Fig. 6C shows a schematic section through the Fig. 6A shown section along the Fig. 6B shown section line DD; and Fig. 6D schematically shows a section through the Fig. 6A shown section along the Fig. Section line EE shown in Figure 6B.

[0041] Here and in the following, features that recur in various figures are designated by the same or similar reference symbols.

[0042] Fig. 1 shows an electrochemical system 1 with a plurality of identical metallic separator plates 2, which are arranged in a stack 6 and stacked along a z-direction 7. The separator plates 2 of the stack 6 are clamped between two end plates 3, 4. The z-direction 7 is also called the stacking direction. In the present example, the system 1 is a fuel cell stack. Two adjacent separator plates 2 of the stack enclose an electrochemical cell between them, which serves, for example, to convert chemical energy into electrical energy. To form the electrochemical cells of the system 1, a membrane electrode assembly (MEA) 10 is arranged between each adjacent separator plates 2 of the stack (see, for example, Fig. 2). The MEAs 10 typically each contain at least one membrane, e.g., an electrolyte membrane. Furthermore, a gas diffusion layer (GDL) may be arranged on one or both surfaces of the MEA, in which Fig. 1 and 2 not shown but for example in Fig. 3 can be seen.

[0043] In alternative embodiments, system 1 can also be designed as an electrolyzer, electrochemical compressor, or redox flow battery. Separator plates can also be used in these electrochemical systems. The structure of these separator plates can then correspond to the structure of the separator plates 2 explained in more detail here, even if the media conveyed onto or through the separator plate in an electrolyzer, an electrochemical compressor, or a redox flow battery can differ from the media used for a fuel cell system. In particular, the separator plates can each comprise only one individual plate.

[0044] The z-axis 7, together with an x-axis 8 and a y-axis 9, spans a right-handed Cartesian coordinate system. The separator plates 2 each define a plate plane, wherein the plate planes of the individual plates 2a, 2b are each aligned parallel to the xy-plane and thus perpendicular to the stacking direction or to the z-axis 7. The end plate 4 has a plurality of media connections 5 through which media can be supplied to the system 1 and through which media can be removed from the system 1. These media that can be supplied to the system 1 and removed from the system 1 can include, for example, fuels such as molecular hydrogen or methanol, reaction gases such as air or oxygen, reaction products such as water vapor or depleted fuels, or coolants such as water and / or glycol.

[0045] Fig. Figure 2 shows in perspective two adjacent separator plates 2 of an electrochemical system of the type of system 1 from Fig. 1 and a membrane electrode assembly (MEA) 10 arranged between these adjacent separator plates 2, which is known from the prior art, wherein the MEA 10 is Fig. 2 is largely concealed by the separator plate 2 facing the viewer. The separator plate 2 is formed from two materially joined individual plates 2a, 2b (see e.g. Fig. 3), of which Fig. 2, only the first individual plate 2a facing the viewer is visible, concealing the second individual plate 2b. The individual plates 2a, 2b can each be made of a metal sheet, e.g., a stainless steel sheet. The individual plates 2a, 2b can be welded to one another, e.g., by laser welding. On the one hand, the individual plates 2a, 2b can be tightly welded along and spaced from their outer edges or at least along the inner edge of a portion of the through-openings along sealing seams, in particular outside and / or inside the perimeter bead 12d. Further weld seams, for example, in the area between the channels 30 to be explained later, are possible.

[0046] The individual plates 2a, 2b have through-openings aligned with one another, which form through-openings 11a-c of the separator plate 2. When stacking a plurality of separator plates of the type separator plate 2, the through-openings 11a-c form lines that extend in the stacking direction 7 through the stack 6 (see Fig. 1). Typically, each of the lines formed by the through-openings 11a-c is in fluid communication with one of the ports or media connections 5 in the end plate 4 of the system 1. For example, coolant can be introduced into or discharged from the stack via the lines formed by the through-openings 11a. The lines formed by the through-openings 11b, 11c, on the other hand, can be designed to supply the electrochemical cells of the fuel cell stack 6 of the system 1 with fuel and reaction gas, as well as to discharge the reaction products from the stack. The media-carrying through-openings 11a-11c are designed essentially parallel to the plate plane.

[0047] To seal the through-openings 11a-c from the interior of the stack 6 and from the environment, the first individual plates 2a each have sealing arrangements in the form of sealing beads 12a-c, which are each arranged around the through-openings 11a-c and which completely enclose the through-openings 11a-c. The second individual plates 2b have, on the side facing the viewer of the Fig. 2, corresponding sealing beads are provided on the rear side of the individual plates 2 for sealing the through openings 11a-c (not shown). Alternatively, elastomer seals can also be used.

[0048] In an electrochemically active area 18, the first individual plates 2a have, at their position facing the observer, Fig. 2 facing outside a flow field 17 with structures for guiding a reaction medium along the outside of the single plate 2a. These structures are shown in Fig. 2 by a plurality of webs 32 and channels 30 extending between the webs 32 and delimited by the webs 32. At the viewer of the Fig. 2 facing the outer side of the separator plates 2, the first individual plates 2a each have a distribution and collection area 20. Distribution or collection areas 20 each comprise structures that are configured to distribute a medium introduced from a first of the two through-openings 11b into the distribution area 20 via the active area 18 or to collect or bundle a medium flowing from the active area 18 to the second of the through-openings 11b. The fluid guide structures 29 of both distribution or collection areas 20 are in Fig. 2 channels are also provided, which are also formed by webs and extend between the webs and are delimited by the webs. For the sake of simplicity, only the distribution area 20 is addressed below; the corresponding statements can equally apply to a collection area 20.

[0049] The sealing beads 12a-12c have passages 13a-13c which allow a passage of medium between the associated through openings 12a-12c and the distribution area 20 on a gas side or in the interior of the separator plate 2.

[0050] The first individual plates 2a each further comprise a further sealing arrangement in the form of a perimeter bead 12d, which surrounds the flow field 17 of the active region 18, the distribution and collection regions 20, and the through-openings 11b, 11c and seals them from the through-opening 11a, i.e., from the coolant circuit, and from the environment of the system 1. The second individual plates 2b each comprise corresponding perimeter beads. The structures of the active region 18, the distribution structures of the distribution and collection regions 20, and the sealing beads 12a-d are each formed integrally with the individual plates 2a and molded into the individual plates 2a and 2b, e.g., in a stamping or deep-drawing process or by hydroforming.

[0051] The separator plate 2 is formed from two materially joined individual plates, namely individual plates 2a, 2b (see e.g. Fig. 3), of which Fig. 2, only the first individual plate 2a facing the viewer is visible, which conceals the second individual plate. The individual plates can each be formed from a formed metal sheet, e.g., from a stamped or deep-drawn stainless steel sheet. This metal sheet can, for example, have a thickness of at most 150 µm, preferably of at most 100 µm, preferably of at most 70 µm, particularly preferably of at most 50 µm. The individual plates can be welded together, for example, by laser welding.

[0052] The Fig. Figure 3 shows schematically a section through a portion of the plate stack 6 of the system 1 from Fig. 1, where the cutting plane is aligned in the z-direction and thus perpendicular to the plate planes of the separator plates 2. The cutting plane runs in the Fig. 3 along a bent section, along the section line AA in Fig. 2. It should be noted that the separator plates of the Fig. 3 are schematic and exemplary and serve to illustrate the structure of the electrochemical system, in particular the different layers and regions. The first individual plate 2a has, on its side facing away from the second individual plate 2b, molded-in, side-by-side first channels 30 for media guidance, which are separated from one another by first webs 32 formed between the first channels 30. On a side of the first individual plate 2a facing the second individual plate 2b, the first channels 30 form first elevations 34 and the first webs 32 form first grooves 36. The second individual plate 2b has, on its side facing away from the first individual plate 2a, molded-in, side-by-side second channels 40 for media guidance, which are separated from one another by second webs 42 formed between the second channels 40.On a side of the second individual plate 2b facing the first individual plate 2a, the second channels 40 form second elevations 44 and the second webs 42 form second grooves 46.

[0053] Cooling channels are arranged in the cavity 19 between adjacent individual plates 2a, 2b. In the active region 18, the two individual plates 2a, 2b rest on one another in a contact area 24. The individual plates 2a and 2b can be connected to each other there.

[0054] A membrane electrode assembly (MEA) 10, known from the prior art, is arranged between adjacent individual plates 2 of the stack. The MEA 10 typically comprises a membrane 14, e.g., an electrolyte membrane, and an edge portion 15 connected to the membrane 14. For example, the edge portion 15 can be integrally bonded to the membrane 14, e.g., by an adhesive bond or by lamination.

[0055] Here, the term "electrochemically active area" is used to refer to the area of ​​the individual plates 2a, 2b that lies opposite an electrochemically active area of ​​the MEA 10 when the individual plate 2a, 2b is arranged in an electrochemical system. The membrane of the MEA 10 extends at least over the active area 18 of the adjacent separator plates 2 and enables proton transfer there over or through the membrane 14. The actual active area 18 is delimited by the edge section 15 of the MEA. Thus, the membrane does not extend into the distribution or collection area 20. The edge section 15 of the MEA 10 serves to position, attach, and seal the membrane between the adjacent separator plates 2.

[0056] The edge section 15 covers the distribution or collection area 20 of the adjacent separator plates 2. The edge section 15 can also extend outwards beyond the perimeter bead 12d and there border on the outer edge area of ​​the individual plates 2a, 2b or protrude beyond it (cf. Fig. 2).

[0057] Furthermore, additional gas diffusion layers 16 can be arranged in the active region 18. The gas diffusion layers 16 enable the flow to the membrane 14 over the largest possible area of ​​the membrane surface and can thus improve the proton transfer across the membrane. The gas diffusion layers 16 can, for example, be arranged on both sides of the membrane 14, at least in the active region 18, between the adjacent separator plates 2. The gas diffusion layers 16 can, for example, be formed from a fiber fleece or comprise a fiber fleece.

[0058] Fig. 4A shows an exemplary prior art single plate for a separator plate of an electrochemical system schematically in a plan view. Fig. 4B shows the single plate of the Fig. 4A schematically as a bending beam. In Fig. 4B, the springback RF of the active region and the stiffness S of the bending beam are visualized by arrows. In the active region, compressive stresses present in the separator plate or resulting from the manufacturing process lead to bulging effects, which cause problems when the separator plates are used in an electrochemical system similar to the system of the Fig. 1 is used. These bulging effects can, for example, lead to elements of the separator plate no longer matching the interacting elements of the MEA, or in the case of two-layer separator plates, the elements of the individual plates being geometrically shifted relative to one another. Furthermore, the tools required for subsequent processing steps may no longer match. Stacking can also cause difficulties. If this is counteracted solely by stiffening the edge regions of the separator plates, unwanted wrinkles usually occur, so this is not an effective remedy. The present invention aims to counteract these bulging effects.

[0059] Figure groups 5 and 6 each consider only a first individual plate 2a. A second individual plate 2b could be formed without stiffening elements, but is preferably also formed with stiffening elements. Two individual plates 2a, 2b can be present in a separator plate, in which at least some of the stiffening structures 60 of the first individual plate 2a, in an orthogonal projection onto the second individual plate 2b, overlap the stiffening structures 60 of the second individual plate 2b and / or are arranged offset from them. For example, the individual plates 2a, 2b can be mirror-symmetrical to one another in their active region 18.

[0060] Fig. 5A shows a section of the active area 18 of a single plate 2a of a separator plate 2 of a system according to the type of system according to Fig. 1. The first individual plate 2a has embossed webs 32 on a first side. The webs have web flanks 33. The web flanks 33 laterally define channels 30 for conducting a first fluid. Furthermore, the channels are defined by channel bottoms 301.

[0061] For the sake of clarity, in this figure, the previous and the following figures, only some of the webs 32, web flanks 33, channels 30, channel bottoms 301 or other elements are provided with the respective reference symbols.

[0062] Fig. 5B shows a top view of the section of the Fig. 5A. In Fig. 5B shows sections BB and CC, which are visualized in the following figures 5C and 5D. Section BB ( Fig. 5C) and the section CC ( Fig. 5D) is orthogonal to the longitudinal extension direction of the webs 32.

[0063] The first individual plate 2a has first transition regions I with a first embossing radius between channel bottoms 301 and the adjacent web flanks 33. On a second side of the individual plate 2a, the channels 30 form elevations 34, and the webs 32 form grooves 36 for guiding a second fluid. Between groove bottoms 302 and adjacent elevation flanks 37 forming the grooves, the individual plate 2a has second transition regions II with a second embossing radius. The web flanks 33 of the first side of the individual plate 2a are opposite elevation flanks 37 of the second side of the individual plate 2a.

[0064] The individual plate 2a forms a plurality of stiffening structures 60 arranged in the first I and second transition regions II. The stiffening structures 60 are formed as local curvatures. The curvatures have a radius that is larger than the respective stamping radius. The curvatures extend over a height that is less than a web height H. S . The web height H S along a direction orthogonal to the plate plane between the web bottom or groove bottom 302 and the channel bottom 301. In the section BB ( Fig. 5C), the stiffening structures 60 are formed on one side of each of the two raised flanks 37 defining the grooves. In section CC ( Fig. 5D), the stiffening structures 60 are formed on each side of one of the two web flanks 33 delimiting the channels. The raised flanks 37 forming the stiffening structures 60 in section BB correspond to the web flank 33 in section CC, which does not form any stiffening structures 60, while the web flanks 33 with stiffening structures 60 in section CC correspond to the raised flanks 37 that do not form any stiffening structures 60 in section BB. The stiffening structures 60 are therefore arranged offset along the elongated extent of the channels or webs 32.

[0065] The web flanks 33 have a first inclination n1 relative to a plate plane P. In the stiffening structure 60, the web flanks 33 have a second inclination n2 relative to the plate plane P. The second inclination n2 is less than the first inclination n1. The plate plane P extends parallel to the xy plane, in particular through the channel bottoms.

[0066] The stiffening structures 60 in the web flanks 33 and in the raised flanks 37 are of the same dimensions in the present case, but can be designed differently in other embodiments.

[0067] The stiffening structures 60, which are Fig. 5D are curved into the channel 30 and protrude into the channel 30. The stiffening structures 60, which are shown in Fig. 5C and are formed in the second transition region II, protrude into the groove 36 and are curved into the groove 36.

[0068] The stiffening structures 60 have a maximum elongated extension along the elongated channel extension or groove extension that is greater than 0.1 times the web height but less than 2.5 times the web height. The stiffening structures formed in a web flank have a maximum lateral extension transverse to the elongated channel extension or groove extension that is greater than 0.2 times the channel width measured at half height in channel sections without local curvatures and less than 0.9 times the channel width measured at half height in channel sections without local curvatures. The stiffening structures formed in a raised flank have a maximum lateral extension transverse to the elongated channel extension orGroove extension that is greater than 0.2 times the groove width measured at half height in groove sections without local curvatures and less than 0.9 times the groove width measured at half height in groove sections without local curvatures. The web flank comprising the stiffening structure 60 is inclined by a maximum of 55° to the plate plane in the area of ​​greatest curvature of the stiffening structure 60.

[0069] As in the Fig. As can be seen from Figures 5A to 5D, the stiffening structures 60 are arranged in a plurality of channels 30 and in a plurality of grooves 36. In the longitudinal direction of the channel, the stiffening structures 60 originate alternately from a first and a second web flank 33 delimiting the respective channel. In the longitudinal direction of the groove, the stiffening structures originate alternately from a first and a second raised flank 37 delimiting the respective groove. The stiffening structures 60 of a channel 30 are arranged offset in the direction of the channel extension relative to stiffening structures 60 of an adjacent groove 36. Overall, this results in a sequence of four different stiffening structures. The stiffening structures 60 have constant spacing from one another in the longitudinal direction (x-direction) and in the transverse direction (y-direction).

[0070] Fig. 6A shows a section of a single plate 2a of a separator plate 2 of a system according to the type of system according to Fig. 1. The first individual plate 2a has embossed webs 32 on a first side. The webs 32 have web flanks 33. The web flanks 33 laterally define channels 30 for conducting a first fluid. Furthermore, the channels are defined by channel bottoms 301.

[0071] Fig. 6B shows a top view of the section of the Fig. 6A. In Fig. Sections DD and EE are shown in Figure 6B, which are visualized in the following Figures 6C and 6D. Section DD ( Fig. 6C) and the section EE ( Fig. 6D) each run orthogonally to the longitudinal extension direction of the webs 32.

[0072] The first individual plate 2a has first transition regions I with a first embossing radius between channel bottoms 301 and the adjacent web flanks 33. On a second side of the individual plate 2a, the channels 30 form elevations 34, and the webs 32 form grooves 36 for guiding a second fluid. Between groove bottoms 302 and adjacent elevation flanks 37 delimiting the grooves 36, the individual plate 2a has second transition regions II with a second embossing radius. The web flanks 33 of the first side of the individual plate 2a are opposite elevation flanks 37 of the second side of the individual plate 2a.

[0073] The individual plate 2a forms a plurality of stiffening structures 60 arranged in the first transition regions I. The stiffening structures 60 are formed as local curvatures. The curvatures have a radius that is larger than the respective stamping radius. The curvatures extend over a height that is less than a web height H.S . The web height H S along a direction orthogonal to the plate plane between the web bottom or groove bottom 302 and the channel bottom 301. In the section DD ( Fig. 6C), the stiffening structures 60 are formed on one side of each of the two web flanks 33 defining the channels 30. In the section EE ( Fig. 6D), the stiffening structures 60 are formed on the other side of the two web flanks 33 delimiting the channels 30.

[0074] As in the Fig. As can be seen from Figures 6A to 6D, the stiffening structures 60 are arranged in a plurality of channels. The stiffening structures 60 originate alternately from a first and a second web flank 33 delimiting the respective channel 30 in the elongated channel profile. The stiffening structures 60 have constant spacing from one another in the longitudinal direction (x-direction) and in the transverse direction (y-direction).

[0075] The web flanks 33 have a first inclination n1 relative to a plate plane P. In the stiffening structure 60, the web flanks 33 have a second inclination n2 relative to the plate plane P. The second inclination n2 is less than the first inclination n1. The plate plane P extends parallel to the xy plane, in particular through the channel bottoms.

[0076] The stiffening structures 60 in the web flanks 33 are of the same dimensions in the present case, but can be designed differently in other embodiments.

[0077] The stiffening structures 60, which are Fig. 6C and Fig. 6D are curved into the channel 30 and each protrude into the channel 30.

[0078] The stiffening structures 60 have a maximum elongated extension along the elongated channel extension or groove extension that is greater than 0.1 times the web height but less than 2.5 times the web height. The stiffening structures, which are formed here in a web flank, have a maximum lateral extension transverse to the elongated channel extension or groove extension that is greater than 0.2 times the channel width measured at half height in channel sections without local curvatures and less than 0.9 times the channel width measured at half height in channel sections without local curvatures. The web flank having the stiffening structure 60 is in Fig. 6 in the area of ​​greatest curvature of the stiffening structure 60 inclined by a maximum of 45° to the plate plane P.

Claims

[1] Separator plate for an electrochemical system, with a first single plate (2a), - wherein the first individual plate (2a) has embossed webs (32) on a first side with web flanks (33) that partially delimit channels (30), wherein the channels (30) are designed to guide a first fluid, wherein the first individual plate (2a) has first transition regions (I) with a first embossing radius between channel bottoms (301) and the adjacent web flanks (33); - wherein on a second side of the individual plate (2a) the channels (30) form elevations (34) and the webs (32) form grooves (36) for guiding a second fluid, wherein the first individual plate (2a) has second transition regions (II) with a second embossing radius between groove bottoms and adjacent elevation flanks forming the grooves; characterized byin that the first individual plate (2a) forms a plurality of stiffening structures (60) which are arranged in the first and / or second transition regions, wherein the stiffening structures (60) form local curvatures, wherein the curvatures have a radius which is greater than the respective embossing radius and wherein the curvatures extend over a height which is less than a web height. [2] Separator plate (2) according to claim 1, wherein at least some of the stiffening structures in the first transition region (I) are curved into the channel (30) and protrude into the channel (30) and / or wherein at least some of the stiffening structures (60) in the second transition region (II) are curved into the groove (36) and protrude into the groove (36). [3] Separator plate (2) according to claim 1 or 2, wherein the stiffening structures have a maximum elongated extension along the elongated channel extension or groove extension which is greater than 0.1 times the web height, preferably greater than 0.15 times the web height, particularly preferably greater than 0.2 times the web height and / or wherein the stiffening structures have a maximum elongated extension along the elongated channel extension or groove extension which is smaller than the web height, preferably smaller than 2.5 times the web height, particularly preferably smaller than 1.5 times the web height. [4] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures have a maximum elongated extension along the elongated channel extension or groove extension which is greater than 120 µm, preferably greater than 130 µm, particularly preferably greater than 150 µm, and / or wherein the stiffening structures have a maximum elongated extension along the elongated channel extension or groove extension which is less than 3 mm, preferably less than 2 mm, particularly preferably less than 1 mm. [5] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures have a maximum lateral extension within the respective channel or within the respective groove transversely to the elongated channel extension or groove extension, which is greater than 0.2 times the channel or groove width measured at half height in sections of the same channel or the same groove without local bulges, preferably greater than 0.3 times the channel or groove width measured at half height in sections of the same channel or the same groove without local bulges, particularly preferably greater than 0.4 times the channel or groove width measured at half height in sections of the same channel or the same groove without local bulges and / or wherein the stiffening structures in a channel have a maximum lateral extension transverse to the elongated channel extension or groove extension, which is smaller than the channel width measured at half height in channel sections without local curvatures, preferably smaller than 0.9 times the channel width measured at half height in channel sections without local curvatures, particularly preferably smaller than 0.8 times the channel width measured at half height in channel sections without local curvatures and / or wherein the stiffening structures in a groove have a maximum lateral extension transverse to the elongated channel extension or groove extension, which is smaller than the groove width measured at half height in groove sections without local curvatures, preferably smaller than 0.9 times the groove width measured at half height in groove sections without local curvatures, particularly preferably smaller than 0.8 times the groove width measured at half height in groove sections without local curvatures [6] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures have a maximum extension in the direction of the web height which is a maximum of 95%, preferably a maximum of 90%, particularly preferably a maximum of 80% of the web height. [7] Separator plate (2) according to one of the preceding claims, wherein the web flank having the stiffening structure (60) is inclined to the plate plane by a maximum of 55°, preferably a maximum of 50°, in particular a maximum of 45° in the region of a greatest curvature of the stiffening structure. [8] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures are arranged in a plurality of channels (30) and / or a plurality of grooves (36). [9] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures in the elongated channel course originate from a first and / or a second web flank delimiting the respective channel and / or in the elongated groove course originate alternately from a first and / or a second raised flank delimiting the respective groove. [10] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures are arranged only in channels or only in grooves. [11] Separator plate (2) according to one of the preceding claims, wherein stiffening structures of a channel are arranged offset in the channel extension direction to stiffening structures of an adjacent groove. [12] Separator plate (2) according to one of the preceding claims, wherein the separator plate has more stiffening structures in central regions of the separator plate than in edge regions of the separator plate. [13] Separator plate (2) according to one of the preceding claims, wherein the stiffening structures are distributed over the separator plate and have at least partially constant and / or at least partially varying distances from one another. [14] Separator plate (2) according to one of the preceding claims, wherein at least two of the stiffening structures have different geometries. [15] Separator plate (2) according to one of the preceding claims, comprising a second single plate (2b) connected to the first single plate (2a), wherein the second individual plate has embossed webs (42) on a first side of the second individual plate with web flanks that partially delimit channels (40) for guiding a third fluid, wherein the second individual plate (2b) has third transition regions with a third embossing radius between channel bottoms and the adjacent web flanks; wherein on a second side of the second individual plate (2b) the channels (40) form elevations (44) and the webs (42) form grooves (46) for guiding the second fluid, wherein the second individual plate (2b) has fourth transition regions with a fourth embossing radius between groove bottoms and adjacent elevation flanks which delimit the grooves (46) at least in sections. [16] Separator plate (2) according to the preceding claim, wherein the second individual plate (2a) forms a plurality of stiffening structures (60) which are arranged in the third and / or fourth transition regions, wherein the stiffening structures are locally curved into the channel (40) in the third transition regions and are locally curved into the groove (46) in the fourth transition regions, wherein the curvatures have a radius which is greater than the respective embossing radius and smaller than a web height of the second individual plate. [17] Separator plate (2) according to the preceding claim, wherein the stiffening structures (60) of the first individual plate (2a) differ at least in part of their properties from the stiffening structures (60) of the second individual plate (2b). [18] Separator plate (2) according to one of the preceding claims, insofar as these are dependent on claims 15 or 16, wherein at least some of the stiffening structures (60) of the first individual plate (2a) overlap the stiffening structures (60) of the second individual plate (2b) in an orthogonal projection onto the second individual plate (2b) and / or are arranged offset relative to these. [19] Electrochemical system (1) comprising a plurality of separator plates (2) according to one of the preceding claims.

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