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

Abstract

The invention relates to a separator plate for an electrochemical system, comprising a first single plate, wherein the first single plate has embossed webs on a first side with web flanks that at least partially define channels for guiding a first fluid, wherein the web flanks have a first inclination relative to a plate plane, characterized in that the first single plate has at least one transverse stiffening region that extends transversely to an elongated direction of extension of the webs and in which a second inclination of the web flanks relative to the plate plane is less than the first inclination.

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 pair of adjacent separator plates encloses an electrochemical cell. The separator plates typically comprise two individual plates each, which are connected to one another along their rear sides facing away from the electrochemical cells. 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, 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, so that the electrical current can be utilized.

[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 dependent claim. Further developments are the subject of the subclaims and the following description.

[0007] The proposed separator plate for an electrochemical system comprises a first single plate. The first single plate has embossed webs with web flanks on a first side. The single plate has channels for guiding a first fluid. The web flanks at least partially delimit the channels, and the web flanks can thus also extend partially into the height range considered as the channel depth. The channels can furthermore be delimited by channel bottoms. The web flanks have a first inclination n 1 with respect to a plate plane.

[0008] The first individual plate has at least one transverse stiffening region which extends transversely to an elongate direction of extension of the webs and in which a second inclination n 2 the web flanks relative to the plate plane is less than the first inclination n 1 outside the transverse stiffening area. Usually, n corresponds to 1 the greatest inclination of the web flanks.

[0009] The transverse stiffening area has the advantage that stiffening is carried out directly at the radius where springback occurs during the stamping process.

[0010] In the transverse stiffening area, the second inclination n 2 relative to the plate plane, which is less than the first inclination n 1 , along a longitudinal extension of the channels up to a minimum value n 2, mindecrease and increase again. The inclination can, for example, decrease and / or increase gradually and / or continuously increase and / or decrease. Any steps have radii. This can be due to the stamping process and / or be advantageous for flow guidance, as it can reduce and / or avoid turbulence.

[0011] The channel bottoms and / or web surfaces can, for example, be in the plane of the plate or parallel to the plane of the plate.

[0012] For example, the first slope n 1 correspond to an angle greater than 50°, in particular an angle greater than 60° and less than 85°. Often, inclination n is reduced 2 except for values ​​for n 2, min in the range of 15 to 45°. In particular, the minimum inclination n 2, min at least 15° and a maximum of 50°, in case of a complete lowering with n 2, min =0 maximum 85° less than n1.

[0013] In the transverse stiffening area, the web width of the webs can decrease and increase again along a longitudinal extent of the webs. The web width can be larger in the transverse stiffening area than in areas before and / or after the transverse stiffening area. It can be at the height T k measured, as described below analogously for the channel width.

[0014] In the transverse stiffening region, the webs can be lowered along their elongated extent. This can form a transverse channel running transversely, in particular at right angles, to the elongated direction of extension, in particular in a straight line. Additionally, the channel bottoms can be raised, so that a transverse channel is created not only on the side of the first individual plate on which the webs project, but also on the opposite surface of the first individual plate. This allows for the mixing of the media within at least two separate media spaces, in particular to compensate for concentration gradients. In extreme cases, the second inclination n is reduced. 2, min to 0°.

[0015] A permissible free span of the GDL can define the width of the gap between the webs. In particular, the gap can be selected as small as possible. The gap can be at least 0.5 mm, in particular at least 0.6 mm and / or at least 0.7 mm. The gap can, for example, be at most 1.5 mm, in particular at most 1.4 mm and / or at most 1.2 mm.

[0016] A channel depth and a web height can be considered separately. In this case, a maximum extension of the entire structure can be measured along a direction orthogonal to the slab plane between the web underside and the channel floor. A reference line can be defined halfway up the maximum extension between the web underside and the channel floor. The web height can be measured along the direction orthogonal to the slab plane, starting from the reference line to the web underside. The channel depth can be measured along the direction orthogonal to the slab plane, starting from the reference line to the channel floor. However, it is also possible for the web height and the channel depth to be different, for example, if the channel(s) are raised to a different extent than the web is lowered within a transverse stiffening area. In this case, the reference line preferably does not extend halfway up, but rather according to the distances.

[0017] The maximum extent of the overall structure and / or the web height and / or the channel depth in the cross - stiffening region may deviate from the maximum extent of the overall structure and / or from the web height and / or from the channel depth outside the cross - stiffening region.

[0018] In particular, a channel depth of the channels and / or a web height of the webs in the cross - stiffening region may deviate from the channel depth of the channels or from the web height of the webs in regions in the flow direction before and / or after the cross - stiffening region. The term "before and / or after the cross - stiffening region" in this document always refers, unless otherwise specified, to the flow direction, i.e., the extent direction of the channels or webs.

[0019] The channel depth in the transverse stiffening region can be at least 0.2 times and / or at least 0.3 times and / or at least 0.4 times and / or at most 1.5 times and / or at most 1.3 times and / or at most 1.1 times the channel depth outside the transverse stiffening region. As described above, the channel depth outside the transverse stiffening region can be half the height of the entire structure outside the transverse stiffening region.

[0020] The channel depth of the channels can vary from channel to channel in the transverse stiffening area. Some or all of the channels in a transverse stiffening area can have different channel depths. Similarly, the web height of the webs can vary from web to web.

[0021] Additionally or alternatively, the channel depth of the channels can vary along their longitudinal extent. In particular, the channel depth can vary along their longitudinal extent in the transverse stiffening region, for example, increasing, decreasing, and increasing again. Similarly, the web height of the webs can vary along their longitudinal extent.

[0022] The first individual plate may have more than one transverse stiffening region. The channel depth and / or web height may vary in at least some of the transverse stiffening regions. In particular, an asymmetrical arrangement of the transverse stiffening regions and / or channel depths and / or web heights may be provided. This may serve to optimize flow.

[0023] The channel width of the channels in the transverse stiffening area may be smaller than in the areas before and / or after the transverse stiffening area. The channel width may be at the reference point at half the height of the maximum extension (hereinafter also referred to as "half height" or "T k ") between the underside of the web and the channel floor. Alternatively, the channel width can be measured from the channel floor at a height of 0.8 times T k be measured.

[0024] The channel width at half height may be at least 0.7 mm and / or at least 0.8 mm and / or at least 0.9 mm and / or at most 3 mm and / or at most 2.9 mm and / or at most 2.8 mm. The channel width at half height may taper to a radius towards the channel bottom.

[0025] A channel width of the channels measured on the channel bottoms as well as a web height of the webs measured on the webs in the transverse stiffening area can be larger than in areas before and / or after the transverse stiffening area.

[0026] The number of channels before the transverse stiffening area can be equal to the number of channels after the transverse stiffening area.

[0027] In a section in a transverse stiffening area transverse to the longitudinal direction of extension, each web flank can have the same second inclination n 2 relative to the plate plane, which is less than the first inclination n 1 .

[0028] In a section within the transverse stiffening region, transversely, in particular substantially orthogonally, to the longitudinal extension direction, some or all of the channels may be of the same type and some or all of the webs may be of the same type. In particular, the edge channels and / or webs may be different from the further channels and / or webs.

[0029] In a section outside the transverse stiffening region, transversely, in particular substantially orthogonally, to the longitudinal extension direction, some or all of the channels may be of the same type and some or all of the webs may be of the same type. In particular, the edge channels and / or webs may be different from the further channels and / or webs.

[0030] The separator plate can have a distribution region, a collection region, and an active region fluidically arranged between the distribution and collection regions. The transverse stiffening region can be arranged in the active region.

[0031] The separator plate may comprise several transverse stiffening regions, which may be arranged one behind the other in the direction of fluid flow. The transverse stiffening regions may be evenly distributed relative to the flow direction.

[0032] One or more of the transverse stiffening regions can extend transversely, in particular orthogonally and / or in an arcuate manner and / or in an x-shape and / or in a v-shape and / or in a >-shape and / or <-shape to the longitudinal direction of extension of the channels.

[0033] At least one, preferably several, of the transverse stiffening regions can extend transversely across the entire active region. The shapes of the transverse stiffening regions can vary. For example, an X-shaped, an arc-shaped, and an orthogonally extending transverse stiffening region can be provided in an active region.

[0034] A transverse stiffening region can be arranged at least centrally in the active region. A transverse stiffening region can be provided that extends across the entire width of the active region, but only in the central region of the active region in the longitudinal direction of the channels. However, the stiffening region does not have to extend across the entire width of the active region. It is also possible for multiple transverse stiffening regions to be provided in the middle half or middle third relative to the longitudinal direction of the channels.

[0035] The number of transverse stiffening regions may increase towards one side of the active region, in particular in or against the fluid flow direction.

[0036] Advantageously, the transverse stiffening areas are arranged only within the active area, i.e. not in the distribution or collection area.

[0037] Likewise, multiple transverse channels are possible, which are preferably located in the center (largest bulge) or also recurring (constant or varying distances from one another), for example, in the center and / or toward one end of the active region. This can have advantages with regard to media distribution, particularly for gas and / or coolant, and can lead to increased stack performance. In particular, the coolant flow can be better controlled from the outside to the inside in a top view of the plate and in the flow direction.

[0038] The separator plate can have a second individual plate. The second individual plate can have embossed webs on a first side. The webs can have web flanks that, at least in sections, delimit channels for conducting a second fluid. The second individual plate can be connected to the first individual plate on a second side, facing away from the first side.

[0039] The present disclosure further relates to an electrochemical system comprising a plurality of separator plates. At least one, preferably a plurality, and / or all of the separator plates correspond to the above description.

[0040] Exemplary embodiments of the separator plate and the electrochemical system are illustrated in the figures and 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 an active area of ​​a single plate of a system of the type according to Fig. 1; Fig. 5B schematically shows a plan view of the Fig. 5A shown section; 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. 5E schematically shows a section through the Fig. 5A shown section along the Fig. section line DD shown in Figure 5B; Fig. 5F schematically shows a section through the Fig. 5A shown section along the Fig. section line EE shown in Figure 5B; Fig. 5G schematically shows a section through the Fig. 5A shown section along the Fig. 5B shown section line FF; Fig. 5H shows a schematic section through the Fig. 5A shown section along the Fig. 5B shown section line GG; Fig. 51 schematically shows a detail N of the Fig. 5C shown section along the Fig. 5B shown section line BB; Fig. 6A schematically shows a perspective view of a section of an active area of ​​a single plate of a system of the type according to Fig. 1; Fig. 6B schematically shows a plan view of the Fig. 6A shown section; Fig. 6C schematically shows a section through the Fig. 6A shown section along the Fig. 6B shown section line KK; Fig. 6D schematically shows a section through the Fig. 6A shown section along the Fig. 6B shown section line LL; Fig. 6E schematically shows a section through the Fig. 6A shown section along the Fig. 6B shown section line MM; Fig. 7A schematically shows a plan view of a single plate of a system of the type according to Fig. 1, Fig. 7B schematically shows a plan view of a single plate of a system of the type according to the system according to Fig. 1, Fig. 7C schematically shows a plan view of a single plate of a system of the type according to Fig. 1 and Fig. 7D schematically shows a plan view of a single plate of a system of the type according to Fig. 1.

[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. Each 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 and Fig. 3). The MEAs 10 typically each contain at least one membrane, e.g., an electrolyte membrane. Furthermore, a gas diffusion layer (GDL) may be disposed on one or both surfaces of the MEA, in Fig. 1 and 2 not shown but for example in Fig. 3 can be seen.

[0043] In alternative embodiments, the system 1 can also be designed as an electrolyzer, an electrochemical compressor, or a 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 guided on 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 exactly 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, with the plate planes of the individual plates 2a, 2b 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, which conceals 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, for example, 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 are possible, for example, in areas between the webs, as will be explained later.

[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 for sealing the through-holes 11a-c (not shown) are provided on the rear side of the individual plates 2 facing away from the respective plates. Alternatively, elastomer seals can also be used.

[0048] In an electrochemically active area 18, the first individual plates 2a have, at their side 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, 42 and channels 30, 40 extending between the webs 32, 42 and delimited by the webs 32, 42. 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 conducting 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 through-openings 11a-c are arranged in groups of three on each longitudinal edge, i.e. on both sides of the active region 18 in extension of the channels. Such an arrangement of the through-openings with at least one through-opening per medium per longitudinal edge is particularly space-saving. Within the active region 18, the channels of the flow field can have a substantially straight course, as shown, or a wave-shaped course with a substantially straight macroscopic extension direction (cf. DE 10 2023 207 433 A1). The flow directions of the media can all be parallel or partially parallel and partially in counterflow to one another. The preferred embodiment, however, does not provide for any cross-flow in the active region 18 or even a change in direction of more than 45° for one of the media. In particular, the channels of the active region have a flow direction ormacroscopic extension direction, which corresponds to the x-direction of the Cartesian coordinate system.

[0050] 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.

[0051] 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.

[0052] 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 to one another, for example, by laser welding.

[0053] The Fig. 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, in particular, the different positions and areas of the structure of the electrochemical system.

[0054] The first individual plate 2a has, on its side facing away from the second individual plate 2b, molded-in, adjacent 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, adjacent 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.

[0055] 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.

[0056] The first channels 30 and first webs 32 of the first individual plate 2a have the same period length Pe as the second channels 40 and second webs 42 of the second individual plate 2b. This is also preferred for the subsequent separator plates 2, even if only individual plates 2a, 2b are shown here.

[0057] A membrane electrode assembly (MEA) 10, known, for example, 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 connected to the membrane 14, e.g., by an adhesive bond or by lamination.

[0058] Here, the term "electrochemically active area" is used to refer to the area of ​​the individual plate 2a, 2b that is 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.

[0059] The edge section 15 respectively covers the distribution or collection area 20 of the adjacent separator plates 2. Towards the outside, the edge section 15 can also extend beyond the peripheral bead 12d and border on or protrude beyond the outer edge area of the individual plates 2a, 2b there (cf. Fig. 2).

[0060] Furthermore, gas diffusion layers 16 can be arranged additionally in the active area 18. The gas diffusion layers 16 enable the membrane 14 to be flowed over as large an area of the surface of the membrane as possible and can thus improve the proton transfer across the membrane. The gas diffusion layers 16 can e.g. be arranged on both sides of the membrane 14 at least in the active area 18 between the adjacent separator plates 2. The gas diffusion layers 16 can e.g. be formed from a nonwoven fabric or comprise a nonwoven fabric.

[0061] Fig. Figure 4A shows a schematic plan view of an exemplary prior art single plate for a separator plate of an electrochemical system. 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 Fig. 1 is used. These bulging effects can, for example, lead to elements of the separator plate no longer fitting together with 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 fit. Stacking can also cause difficulties. If this is counteracted solely by stiffening the edge regions of the separator plates, unwanted wrinkling usually occurs, so this is not an effective antidote. The present invention has the object of counteracting these bulging effects.

[0062] 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 delimit channels 30 for conducting a first fluid. Furthermore, the channels are delimited by channel bottoms 301.

[0063] For the sake of clarity, in this figure, the previous and the following figures, only some of the elements, such as webs, web flanks, channels and channel bottoms, are provided with the respective reference symbols.

[0064] The first individual plate 2a has at least one transverse stiffening region Q, which extends transversely to an elongate direction of extension of the webs 32. The transverse stiffening region shown extends orthogonally to the elongate direction of extension of the webs 32 and extends over the entire width of the illustrated section, preferably over the entire width of the active region of the first individual plate 2a.

[0065] Outside the transverse stiffening area Q, the web flanks 33 have a first inclination n relative to a plate plane P 1 In the transverse stiffening area Q, the web flanks 33 have a second inclination n relative to the plate plane P 2 The second inclination n 2 is less than the first slope n 1 . The plate plane P extends parallel to the xy-plane.

[0066] Fig. 5B shows a top view of the section of the Fig. 5A. In Fig. 5B shows sections BB to GG, which are visualized in the following figures 5C to 5H. The section BB ( Fig. 5C) is orthogonal to the longitudinal extension direction of the webs 32 in an area outside the transverse stiffening area Q. Here, all web flanks 33 have the same inclination n 1 on.

[0067] Fig. 51 shows the detail N of section BB of the Fig. 5C.

[0068] This includes a channel depth T k and a web height H S A maximum extension of the entire structure G can be measured along a direction orthogonal to the plate plane between the underside of the web and the channel floor. A reference line N 0 can be defined halfway up the maximum extension G between the web bottom and the channel bottom. Along the direction orthogonal to the plate plane P, starting from the reference line N 0 to the bottom of the web the web height H S Along the direction orthogonal to the plate plane P, starting from the reference line N 0 to the canal bottom the canal depth T K measured. Pe represents the period of channels and webs perpendicular to the flow direction x.

[0069] In Fig. 5D shows section CC. Section CC lies in the transverse stiffening area Q. The channel depth T Kis lower in the area of ​​section CC than in the area of ​​section BB. In Fig. 5E shows section DD. Section DD runs orthogonal to the plate plane P and orthogonal to the longitudinal extension direction of the webs 32. The channel depth T K is lower in the area of ​​section DD than in the area of ​​section CC. The inclination n 2 of the web flanks 33 is in section DD with approximately 30° less than in section CC, where the flank angle is approximately 50° and less than in section BB, where the flank inclination n 1 corresponds to a flank angle of approximately 75°. In the transverse stiffening area, the second inclination n 2 opposite the plate plane P along the longitudinal extent of the channels 30 and closes again.

[0070] In Fig. 5F shows the section EE, which lies in the transverse stiffening area Q. The section EE runs orthogonal to the plate plane P and orthogonal to the longitudinal extension direction of the webs 32. The inclination n 2 the web flanks 33 is in section EE equal to zero and thus corresponds to the minimum value n 2, min , so that no webs 32 are formed in this area, but rather a transverse channel Q G orthogonal to the longitudinal extension direction of the webs 32. Fig. 5G visualizes cut FF, which is Fig. 5B cuts longitudinally to the longitudinal extension direction of a channel 30. In the area of ​​the transverse stiffening region Q, the channel bottoms 301 are raised, rising at an angle of between 5° and 15°, here approximately 7°. This results in a transverse channel Q Kfor the medium guided on the underside, especially for the cooling medium. In the areas outside the transverse stiffening area Q, the channels have a constant channel depth T K on. Fig. 5H visualizes section GG, which Fig. 5B cuts along the longitudinal direction of a web 32. In the area of ​​the transverse stiffening area Q, the webs 32 are lowered in order to form the transverse channel Q G to form, but here the subsiding floors run at an angle of approximately 30°. In the area outside the transverse stiffening area Q, the webs have a constant web height H S The transverse channel Q G the Fig. 5 is linear and runs parallel to the y-axis. In other examples, the transverse channel may have a different shape, for example, curved, wave-shaped, or x-shaped. The number of webs 32 and channels 30 in the flow direction upstream of the transverse stiffening region Q corresponds to the number of webs 32 and channels 30 downstream of the transverse stiffening region Q.

[0071] Fig. Figure 6A shows a section of the active area 18 of a single plate 2a of a separator plate 2 of a system of the type 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 delimit channels 30 for conducting a first fluid. Furthermore, the channels are delimited by the channel bottoms 301. The first individual plate 2a has at least one transverse stiffening region Q, which extends transversely to an elongate direction of extension of the webs 32. The transverse stiffening region Q shown extends orthogonally to the elongate direction of extension of the webs 32 and extends over the entire width of the section shown, preferably over the entire width of the active region of the first individual plate 2a. Outside of the transverse stiffening region Q, the web flanks 33 have a first inclination n relative to a plate plane P. 1 In the transverse stiffening area Q, the web flanks 33 have an inclination n relative to the plate plane P 2 or n 2, minwhich are less than the first inclination n 1 . The inclination n 2, min is lower than the other inclinations n 2 . The plate plane P extends parallel to the xy-plane.

[0072] Fig. 6B shows a top view of the section of the Fig. 6A. In Fig. 6B, sections KK, LL and MM are shown, which are visualized in the following figures 6C to 6E. The sections KK, LL and MM intersect the shown section of the individual plate 2a orthogonally to the longitudinal extension direction of the webs 32. The section KK lies outside the transverse stiffening region Q, while the sections LL and MM lie within the transverse stiffening region Q. In the flow direction, a web width of the webs decreases and increases again along a longitudinal extension of the webs 32 in the transverse stiffening region Q. The webs 32 are in the shown section of the Fig. 6 along its longitudinal extent, however, is continuous and uninterrupted. The flank inclination decreases steadily from section KK to section MM. The flank angle n 1 is, for example, 70°, the flank angle n 2 in the area of ​​the section LL approximately 50° and the flank angle n 2, min is approximately 30°. The section MM ( Fig. 6E) lies in the transverse direction to the transverse stiffening region and thus in this case along the longitudinal extent of the webs 32 centrally in the transverse stiffening region and shows the region of the smallest web width of the webs 32. In the section LL, which lies in front of the section MM in the flow direction, the web width of the webs is wider than in the section MM and smaller than in the section KK, which lies outside the transverse stiffening region Q. The channels are narrower in the transverse stiffening region Q than in regions before and after the transverse stiffening region Q, with the height being 0.8 times the channel depth measured starting from the channel bottom 301. The channel width of the channels 33 measured on the webs in the transverse stiffening region Q is greater than in regions before and / or after the transverse stiffening region Q.

[0073] The Fig. 7A to 7D each show a plan view of an exemplary single plate 2a of a system according to the type of the system of Fig. 1.

[0074] The single plate of the Fig. 7A comprises two distribution / collection regions 20 and an active region 18 fluidically arranged between the two distribution / collection regions 20. A transverse stiffening region Q is located in the active region 18. The transverse stiffening region Q can be formed as described above. The present transverse stiffening region Q extends parallel to the y-direction and is arranged centrally in the active region in the flow direction. The present transverse stiffening region Q extends transversely across the entire active region 18.

[0075] The single plate of the Fig. 7B comprises two distribution / collection areas 20 and an active area 18 fluidically arranged between the two distribution / collection areas 20. Seven transverse stiffening areas Q 1 to Q 7 are located in the active area 18. The transverse stiffening areas Q 1 to Q 7can be designed as described above. The transverse stiffening areas Q 1 to Q 7 extend parallel to the y-direction. The transverse stiffening areas Q 1 to Q 7 can all be designed in the same way, for example, all in the same way as in Fig. 5. In particular, the transverse stiffening areas Q 1 to Q 7 between each other a distance between the transition between an inclination n 2 and the inclination n 1 of the transverse stiffening area Q x and the transition between the inclination n 1 and the inclination n 2 of the next transverse stiffening area Q x+1 which corresponds to at least twice, at least three times, preferably at least five times, in particular at least ten times the period length Pe. Alternatively, the transverse stiffening regions Q 1 to Q 7be designed differently, for example, some can be like in Fig. 5 described and some as in relation to Fig. 6. The transverse stiffening areas Q 1 to Q 7 are arranged parallel to each other and evenly spaced across the active area 18. The transverse stiffening areas Q 1 to Q 7 extend across the entire active area 18.

[0076] The single plate of the Fig. 7C comprises two distribution / collection areas 20 and an active area 18 fluidically arranged between the two distribution / collection areas 20. Three transverse stiffening areas Q 1 to Q 3 are located in the active area 18. The transverse stiffening areas Q 1 to Q 3 can be designed as described above. The transverse stiffening areas Q 1 to Q 3extend parallel to the y-direction. The transverse stiffening areas Q 1 to Q 3 can all be designed in the same way, for example, all in the same way as in Fig. 5. Alternatively, the transverse stiffening areas Q 1 to Q 3 can be designed differently, for example the transverse stiffening area Q 2 as in Fig. 5 and the transverse stiffening areas Q 1 and Q 3 can be as in relation to Fig. 6. The transverse stiffening areas Q 1 to Q 3 are arranged parallel to each other and evenly spaced across the active area 18. The transverse stiffening areas Q 1 to Q 3 extend across the entire active area 18.

[0077] The single plate of the Fig. 7D comprises two distribution / collection areas 20 and an active area 18 fluidically arranged between the two distribution / collection areas 20. Five transverse stiffening areas Q 1 to Q 5 are located in the active area 18. The transverse stiffening areas Q 1 to Q 5 are all located in two-thirds of the area of ​​the active region 18. The transverse stiffening regions Q 1 to Q 5 can be designed as described above. The transverse stiffening areas Q 1 and Q 3 extend parallel to the y-direction. The transverse stiffening areas Q 4 and Q 5 are arranged in an arc shape, with the transverse stiffening area Q 4 convex and the transverse stiffening areas Q 5 is concave. The transverse stiffening areas Q 4 and Q 5 have interruptions, while the transverse stiffening areas Q 1 to Q 3are continuous. Some or all of the transverse stiffening areas Q 1 to Q 5 can be determined by type of Fig. 5 or according to the type of Fig. 6. The transverse stiffening area Q 2 is arranged at an angle to the x-axis. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2023 207 433 A1

[0049]

Claims

[1] Separator plate for an electrochemical system, comprising a first single plate (2a), wherein - the first individual plate (2a) has embossed webs (32) on a first side with web flanks (33) delimiting channels (30) at least in sections for guiding a first fluid, wherein the web flanks (33) have a first inclination (n 1 ), characterized by that the first individual plate (2a) has at least one transverse stiffening region (Q) which extends transversely to an elongate direction of extension of the webs (32) and in which a second inclination (n 2 ) of the web flanks (33) relative to the plate plane (P) is less than the first inclination (n 1 ). [2] Separator plate according to claim 1, wherein in the transverse stiffening region (Q) the second inclination (n 2 ) relative to the plate plane (P), which is less than the first inclination (n 1), along a longitudinal extent of the channels (30) to a minimum value (n 2, min ) decreases and increases again. [3] Separator plate according to one of the preceding claims, wherein in the transverse stiffening region (Q) a web width of the webs decreases and increases again along a longitudinal extent of the webs (32). [4] Separator plate according to one of the preceding claims, wherein in the transverse stiffening region (Q) the webs are lowered along their elongate extension, so that a transverse channel is formed which runs transversely to the elongate extension direction, in particular in a straight line. [5] Separator plate according to one of the preceding claims, wherein a channel depth of the channels (33) in the transverse stiffening region (Q) deviates from the channel depth of the channels (33) in regions before and / or after the transverse stiffening region (Q) and / or a web height of the webs (32) in the transverse stiffening region (Q) deviates from the web height of the webs (32) in regions before and / or after the transverse stiffening region (Q). [6] Separator plate according to one of the preceding claims, wherein a channel depth of the channels (33) in the transverse stiffening region (Q) varies from channel to channel and / or a web height of the webs (32) in the transverse stiffening region (Q) varies from channel to channel. [7] Separator plate according to one of the preceding claims, wherein a channel depth of the channels (33) and / or a web height of the webs (32) varies along their elongate extent, in particular varies within the transverse stiffening region. [8] Separator plate according to one of the preceding claims, wherein the first single plate has more than one transverse stiffening region (Q) and the channel depth and / or web height is different in at least some of the transverse stiffening regions. [9] Separator plate according to one of the preceding claims, wherein a channel width of the channels (33) measured at 0.8 Tk in the transverse stiffening region (Q) is smaller than in regions before and / or after the transverse stiffening region. [10] Separator plate according to one of the preceding claims, wherein a web width of the webs (32) measured on the webs in the transverse stiffening region (Q) is greater than in regions before and / or after the transverse stiffening region. [11] Separator plate according to one of the preceding claims, wherein the number of channels before the transverse stiffening region (Q) is equal to the number of channels after the transverse stiffening region (Q). [12] Separator plate according to one of the preceding claims, wherein in a section transverse to the longitudinal direction of extension each web flank (33) has the same second inclination (n 2 ) relative to the plate plane (P) which is less than the first inclination (n 1 ). [13] Separator plate according to one of the preceding claims, wherein in a section within the transverse stiffening region and / or outside the transverse stiffening region transversely to the longitudinal direction of extension, the channels are of identical design and the webs are of identical design. [14] Separator plate according to one of the preceding claims, comprising a distribution region, a collection region and an active region fluidically arranged between the distribution and collection regions, wherein the transverse stiffening region (Q) is located in the active region. [15] Separator plate according to one of the preceding claims, comprising a plurality of transverse stiffening regions which are arranged one behind the other in particular in the fluid flow direction, wherein advantageously the number of transverse stiffening regions increases towards one side of the active region. [16] Separator plate according to one of the preceding claims, wherein one or more of the transverse stiffening regions extend transversely, in particular orthogonally and / or arcuately and / or x-shaped and / or v-shaped and / or >-shaped and / or <-shaped to the longitudinal direction of extension of the channels (30). [17] Separator plate according to one of the preceding claims, wherein at least one, preferably several of the transverse stiffening regions extend transversely across the entire active region. [18] Separator plate according to one of the preceding claims, wherein a transverse stiffening region (Q) is arranged at least centrally in the active region. [19] Separator plate (2) according to one of the preceding claims, comprising a second individual plate (2b), wherein the second individual plate (2b) has embossed webs (42) on a first side with web flanks (43) delimiting channels (40) at least in sections for guiding a second fluid and is connected to the first individual plate (2a) on a second side facing away from the first side. [20] An electrochemical system comprising a plurality of separator plates according to any one of the preceding claims.

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