Separator plate for an electrochemical system

Abstract

The invention relates to a separator plate for an electrochemical system. The electrochemical system can be, for example, a fuel cell system, an electrochemical compressor or an electrolyzer.

Description

[0001] Separator plate for an electrochemical system

[0002] The invention relates to a separator plate for an electrochemical system. The electrochemical system can be, for example, a fuel cell system, an electrochemical compressor or a

[0003] electrolyzer.

[0004] Known electrochemical systems usually comprise a plurality of separator plates arranged in a stack, so that each two adjacent separator plates enclose an electrochemical cell. The separator plates can, for example, each have two individual plates that are connected to one another along their rear sides facing away from the electrochemical cells. The separator plates 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). In these cases, they are also referred to as bipolar plates. The separator plates can also serve to dissipate heat that is generated in the cells between the separator plates. Such waste heat can arise, for example, during the conversion of electrical or chemical energy in a fuel cell.

[0005] Typically, the separator plates or their individual plates each have at least one through-opening. In the separator plate stack of the electrochemical system, the through-openings of the stacked separator plates, which are aligned or at least partially overlapping, form media channels for media supply or media removal. To seal the through-openings or the media channels formed by the through-openings of the separator plates, the separator plates also have bead arrangements arranged around the through-opening of the individual plate.

[0006] The separator plates or their individual plates can also have media guide structures for supplying an active area of ​​each individual plate with one or more media and / or for transporting media away. The media guide structures can, for example, comprise channels and / or webs. The active area of ​​an individual plate can enclose or delimit an electrochemical cell. The media can, for example, be 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. In fuel cells, the reaction media, i.e. fuel and reaction gases, are usually guided on the surfaces of the individual plates facing away from one another, while the coolant is usually guided between the individual plates.

[0007] The flanks of the bead arrangement, which is arranged around a through-opening of a separator plate or individual plate, can have one or more passages, which are also referred to herein as openings or include such openings. These passages typically serve to establish a fluid connection between the through-opening of the individual plate or the media channel formed by the through-opening and the active area of ​​the individual plate.

[0008] For example, German Patent Application DE 102 48 531 A1 discloses a single plate having conducting channels that connect to the passages in the bead flank on an outer side of the bead arrangement and that are in fluid communication with a bead interior via the passages in the bead flank. Such conducting channels allow a medium to be passed through the bead arrangement even more precisely. This can increase the efficiency of the electrochemical system. The terms "fluid" and "medium" are used interchangeably in this disclosure.

[0009] However, known separator plates often cannot adequately meet the constantly increasing efficiency requirements.

[0010] The present invention is therefore based on the object of creating a separator plate for an electrochemical system which ensures the highest possible efficiency of the electrochemical system.

[0011] This object is achieved by a separator plate for an electrochemical system according to claim 1. Specific embodiments are described in the dependent claims, in this description and in the figures.

[0012] According to the invention, it was recognized that efficiency losses in known solutions often result from excessive pressure loss during the media passage through the bead arrangements described above. The solution disclosed here enables a reduction of such pressure losses and thus an increase in the efficiency of the operation of the electrochemical system. A separator plate for an electrochemical system is proposed, wherein the separator plate comprises:

[0013] - at least one through-opening to form a media channel for media supply or media discharge, and

[0014] - at least one bead arrangement arranged around the at least one through-opening for sealing the through-opening, wherein the bead arrangement has a first flank facing the through-opening and a second flank facing away from the through-opening, wherein the first flank has a plurality of first openings and the second flank has a plurality of second openings, wherein a first line channel which is in fluid communication with the through-opening is connected to each of the first openings, wherein at least one of the first line channels has a flow cross-section which decreases at least in sections in the direction of the first opening.

[0015] The separator plate can comprise, as described above, two individual plates that are firmly connected to one another, in particular welded. The inner sides of the individual plates can face each other, and their outer sides can face away from each other.

[0016] Any through-holes, bead arrangement, and conducting channel can be molded into the material of the separator plate or cut out of it. In general, each individual plate of the separator plate can be a one-piece component formed from a homogeneous material, in particular a metallic material. Beyond this one-piece and homogeneous component formed from a single material, however, an individual plate can have coatings. The conducting channel and / or the bead arrangement can be formed, for example, by hydroforming, embossing, and / or deep drawing. In the following description, the terms "embossing" or "embossed" can be understood in particular to mean hydroforming, roll embossing, stroke embossing, and / or deep drawing.

[0017] A fluid connection or a fluidic connection within the meaning of this disclosure may be a direct connection without intermediate elements or an indirect connection with additional intermediate elements.

[0018] The bead arrangement can have a bead interior. This can be at least partially delimited by the flanks. The bead interior can be fluidically connected to the through-opening, for example, via the openings and / or conduits disclosed here. For example, a fluid can flow from the through-opening via a first conduit into the bead interior and from there toward an active region of the separator plate.

[0019] In general, the bead arrangement can be elongated and / or comprise a single elongated, embossed sealing bead. The interior of the bead can, in principle, provide a channel-like guide structure. However, as described in the following embodiments, a fluid is guided through the perforations, particularly over the shortest possible path and / or essentially transversely through the interior of the bead.

[0020] The main extension direction of the bead arrangement can run essentially parallel to an edge delimiting the through-opening. If the bead arrangement comprises a wave-like profile with convex and concave sections, as is possible according to embodiments, the convex and concave sections of the wave-like profile each merge into one another at an inflection point. The said main extension direction is then superimposed on this wave shape of the bead arrangement. The main extension direction results, for example, from the connecting line of the inflection points of the neutral axis of the bead arrangement, in particular a bead roof of the bead arrangement.

[0021] The flanks of the bead arrangement can extend at an angle to a plate plane of the separator plate. This plate plane can run parallel to at least one of the flat surface planes of the individual plates and / or coincide with it. Alternatively or additionally, the plate plane can define a plane in which the individual plates touch each other.

[0022] In a conventional manner, the plane of the flat surface can be defined, for example, by an edge of an individual plate or by those flat areas of the separator plate that are not deformed as a result of an embossing or deep-drawing process to form the web-channel structures or beads described herein. On the one hand, the plane of the flat surface can run in the neutral fibers of the corresponding sections of an individual plate; on the other hand, it is also possible to consider the surfaces of the relevant sections of the plates as plane of the flat surface. However, with the latter approach, it is important to note that, when considering distances or the like, the material thickness of only one of two individual plates under consideration is taken into account.

[0023] The flanks of the bead arrangement can, for example, protrude outward from an area of ​​the separator plate or individual plate adjacent to the bead arrangement, which lies in a flat surface plane or runs parallel to it, as well as at an angle of, for example, more than 20° relative to the flat surface plane. In particular, they can merge into an optional bead roof, which, for example, forms a type of height plateau. The flanks can be arranged on either side of the bead roof. The bead roof can run parallel to the flat surface plane, but preferably at a distance from it. The bead roof can, for example, be flat or curved.

[0024] It is also possible for the bead arrangement to have a curved, and in particular continuous and / or constant, cross-section. In this case, the flanks can run close to a transition to adjacent regions and in particular to a plane of the flat surface. A bead crown can run at a distance from such regions or the plane of the flat surface.

[0025] The first flank faces the through-opening. The second flank faces away from the through-opening and, for example, faces a distribution area and / or an active area of ​​the individual plate. The first and second flanks can run parallel to each other, at least in sections, with respect to their longitudinal extent. They can encompass or form opposing side walls of the bead arrangement.

[0026] If the separator plate is formed by connecting two individual plates, a first of the individual plates can have a first sealing bead arranged around the through-opening for sealing the through-opening. Accordingly, the further individual plate can have a second sealing bead arranged around the through-opening for sealing the through-opening. The first sealing bead and the second sealing bead can be arranged overlapping and together form the bead arrangement disclosed here and its sealing bead interior. The latter is preferably fluidically connected to the through-opening of the individual plate. The first sealing bead and the second sealing bead are typically formed on opposite sides of the separator plate and generally point away from each other with their bead roofs.The first sealing bead and the second sealing bead are typically designed as full beads and accordingly usually each comprise two bead flanks connected to each other by a bead roof. Alternatively, it is possible for the sealing bead interior to be spanned by only one sealing bead in one of the individual panels disclosed here and not also in the optional additional individual panel. The additional individual panel can, for example, run flat opposite the sealing bead.

[0027] The solution disclosed here can therefore include that all of the aforementioned shape and / or structural features, in particular the flanks, openings and conducting channels, are formed in only one single plate.

[0028] An opening can be understood, for example, as a local opening in a flank through which fluid can enter the bead interior. The opening can be formed on an exposed outer side of the flank and / or lie in a plane of the flank. The opening can be completely surrounded by a material of the flank and / or bead. In particular, it can be formed as a hole-like recess in the flank and / or spaced by remaining flank material from a region of the separator plate adjacent to the bead arrangement and in particular from its flat surface plane. In summary, the opening and in particular a hole-like opening can be formed in a region of the separator plate which is at a distance from a flat surface plane of the separator plate and / or which is an embossed region of the individual plate.

[0029] Alternatively or additionally, the opening can be formed in that the flank is not locally brought back to a level of a region of the separator plate adjacent to the bead arrangement, and in particular of its flat surface plane. In other words, the flank cannot be locally closed up to its foot region of the flank opposite the bead roof. Instead, the flank material, which is an embossed material of the plate in the region of the flank, can be referred to as locally raised and an opening of the type disclosed here can therefore be realized in the form of and / or by means of a corresponding (material) elevation. In this case, the flank material can remain at a distance from a region of the individual plate adjacent to the bead arrangement, and in particular from its flat surface plane, and can, for example, merge into the conduction channel disclosed here.

[0030] Both the first and the second openings can be designed according to any of the variants described herein, whereby mixed forms of different types of openings can also be provided. This can apply both to a comparison of the first and second openings with each other, which can be correspondingly different from each other, as well as to a comparison of the first openings with each other and / or the second openings with each other.

[0031] In one example, the conduit channel merges into a flank or, in other words, is directly molded onto it. For fluid communication with the bead interior, this advantageously occurs in the region of and / or at least partially enclosing an opening in the flank.

[0032] The fluid can generally be guided through the bead arrangement at an angle. In particular, this can be an angle to a longitudinal axis and / or the main extension direction of the bead arrangement. This angle can be, for example, at least 20° and / or up to and including 90°. In general, the fluid can be guided through one of the first conduits and an adjoining first opening into the bead interior and can be guided out of the bead interior again through one of the second openings.

[0033] Because the first openings are fluidically connected to the through-hole via first conduits, the fluid can be guided through the conduits in a targeted manner into the interior of the bead. In particular, this can be done in such a way that the fluid exits the interior of the bead again from one of the second openings while at least partially maintaining this orientation and with minimal pressure losses.

[0034] By reducing the flow cross-section of the conduits, at least in sections, the fluid flow is accelerated toward the entry into the bead interior. This increases the probability that the fluid will flow into the bead interior in the desired manner and, in particular, flow through it without excessive pressure losses. As a result, the fluid reaches the distribution area and the active area in sufficient quantity and at the desired pressure, thus increasing the operating efficiency of an electrochemical system comprising multiple separator plates.

[0035] According to one embodiment, a second conduit channel is connected to each of the second openings. In particular, a first or a second conduit channel can be connected to all of the first openings and all of the second openings, or alternatively, at least to a majority of the first openings and the second openings. This increases the extent of the pressure loss reduction achieved according to the invention when the fluid passes through the sealing bead.

[0036] In this context, at least one of the second conduits can have a flow cross-section that decreases at least partially in the direction of the second opening. This can enable at least a partial maintenance of the flow velocity intentionally increased by the first conduits when crossing the interior of the bead. On the other hand, the flow velocity can be reduced to a desired value by the flow cross-section widening with increasing distance from the bead arrangement, for example, for subsequent flow through a distribution area.

[0037] According to one variant, the at least one first conduit channel and the at least one second conduit channel, which preferably each have a decreasing flow cross-section, are connected to one another by a substantially rectilinear fluid path. This rectilinear fluid path can, in particular, run orthogonally to a main extension direction and / or longitudinal axis of the bead arrangement or at least at an angle of more than 60° thereto. In particular, the first and second conduit channels can be directly opposite one another and / or substantially congruent. The latter can include openings on the two flanks into which the conduit channels respectively open being congruent to one another, for example, in an orthogonal projection into a common plane. The resulting rectilinear fluid path enables rapid flow through the bead interior with low pressure loss.

[0038] Alternatively, the first line channel and the second line channel can also be offset from one another, for example when viewed along a main direction of extent and / or longitudinal axis of the bead arrangement. More precisely, in contrast to the previous embodiment, they can be positioned at different positions along this main direction of extent and / or longitudinal axis and / or not directly opposite one another and / or not substantially congruent with one another. In this case, a fluid path connecting the first and second line channel can still be straight, but not run orthogonally to the main direction of extent and / or longitudinal axis of the bead arrangement. Instead, it can intersect these, for example, at a smaller intersection angle of, for example, less than 40° or less than 30°. A smallest achievable intersection angle can be considered here.It is also possible, however, for the fluid path to be non-linear, for example, with one or more bends or angles. The fact that the first and second channels are not necessarily opposite each other increases the design flexibility in the separator plate construction.

[0039] In general, it can be provided that at least a quarter, at least half, at least three-quarters, or all of the first conduit channels and / or the optional second conduit channels have a flow cross-section that decreases, at least in sections, in the direction of a respective adjoining first or second opening. The more conduit channels are provided with a correspondingly decreasing flow cross-section, the greater the extent to which the advantages of the invention can be achieved.

[0040] Furthermore, to reliably achieve the effects according to the invention, it can be provided that none of the first and second line channels has a flow cross-section that widens at least in sections. At most, a flow cross-section widening can occur over a length of less than 20% or less than 10% and / or only in an immediate connection area to a flank. The latter can be necessary to maintain manufacturing tolerances. Additionally or alternatively, any flow cross-section widening can be spaced by at least a quarter or at least half of a total length of a line channel from the respective opening to which it is connected. According to a further embodiment, a flow cross-section of the at least one first line channel is minimal at a distance of less than 5 mm, in particular less than 2 mm, and in particular less than 1 mm from the first opening.The distance can be measured, for example, along a main extension direction and / or longitudinal axis of the first conduit channel. The correspondingly small distance from the first opening increases the flow-accelerating effect of the first conduit channel, i.e., the fluid can be accelerated as close as possible to the first opening. From a manufacturing perspective, however, it may be preferable not to position the minimum cross-section directly at the first opening to avoid excessively tight radii. Consequently, a distance of the minimum flow cross-section of the first conduit channel from the first opening can be, for example, at least 0.1 mm, at least 0.2 mm, or at least 0.5 mm.

[0041] Likewise, a flow cross-section of any second conduit channel can be minimal at a distance of less than 5 mm, in particular less than 2 mm, and in particular less than 1 mm from the second opening. In this case, too, the distance of the minimum flow cross-section of the second conduit channel from the first opening can be, for example, at least 0.1 mm, at least 0.2 mm, or at least 0.5 mm.

[0042] In a further embodiment, the flow cross-section of the at least one first conduit channel and / or any second conduit channel decreases over a length of at least a quarter or at least half of the total length of the first conduit channel. This decrease, and generally any decrease in the flow cross-section of the first and second conduit channels, can occur, for example, linearly and / or strictly monotonically. It has been shown that a reliable and sufficiently strong flow acceleration can be achieved by a corresponding minimum length.

[0043] In principle, the reduction of the flow cross-section according to the invention can be achieved by reducing the height and / or width of a respective first and / or second duct. According to an optional development, however, the at least one first duct and / or any at least one second duct has a constant height. Alternatively, a change in the height of the first and / or second duct along its length can be smaller than a change in its width. Consequently, a narrowing of the flow cross-section can be significantly attributable to a reduction in width, but not to a reduction in height. This can be preferred for maintaining a uniform height, in particular a maximum height, of the separator plate, at least in some regions.Such a uniform height may, for example, be preferred for forming purposes and / or to provide contact surfaces of uniform height for adjacent components of the electrochemical system.

[0044] The width of any duct may be measured parallel to the plane of the planar surface and / or orthogonal to a height of the duct and / or orthogonal to a main extension direction or longitudinal axis of the duct.

[0045] A further development provides that the reduction in the flow cross-section of the first conduit channel and / or any second conduit channel over a length of 1 mm of a respective channel is a maximum of 30%, preferably a maximum of 25%. The reduction can be considered in comparison to a flow cross-section of 1 mm at the beginning or at an opposite end of the section. On the other hand, the reduction in the flow cross-section of the first conduit channel and / or any second conduit channel over a length of 1 mm of a respective channel can be at least 10%, preferably at least 15%. It has been shown that with such reductions, advantageous accelerations in the flow velocity can be achieved, without, however, reducing the flow rate too much.

[0046] According to a further development, the first duct and / or any second duct has a first flank and a second flank which, at least in sections, extend at an angle of less than 180°, and in particular less than 140°, to one another, thereby reducing the flow cross-section. These flanks can be different from the flanks of the bead arrangement, but can, for example, merge into them. The angle can be defined between planes or axes encompassed by the flanks and, in particular, wall regions formed thereby. At an angle of 180°, the flanks are parallel, and the flow cross-section of a duct is likewise constant, at least at a constant height. If the angle decreases to below 180°, the flanks converge on one another, reducing the width of a respective duct in order to reduce the flow cross-section, particularly at a constant height or a comparatively less rapidly decreasing height.Any angles considered herein may be viewed in a plan view of the separator plate and / or in a flat surface plane or a plane parallel thereto.

[0047] Embodiments of the invention are explained below with reference to the accompanying schematic figures. The same reference symbols may be used for comparable features throughout the figures. If similar features appear multiple times in a figure, only selected ones of these similar features, and not necessarily all of them, may be provided with a corresponding reference symbol.

[0048] Figure 1 shows an electrochemical system comprising several separator plates according to an embodiment of the invention.

[0049] Figure 2 shows a detailed view of a part of the electrochemical system from Figure 1 and in particular of separator plates included therein according to an embodiment of the invention.

[0050] Figure 3 shows a sectional view of a separator plate according to the prior art in the area of ​​a bead arrangement for sealing a through opening.

[0051] Figures 4 - 5 show detailed views of separator plates according to embodiments of the invention.

[0052] Figures 6 - 9 show further detailed views of separator plates according to further embodiments of the invention.

[0053] 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 usually 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 6 thus define an electrochemical cell, 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 6 (see, for example, Fig. 2). The MEA 10 typically contains at least one membrane, e.g., an electrolyte membrane.Furthermore, a gas diffusion layer (GDL) can be arranged on one or both surfaces of the MEA 10. The MEA 10 also often includes a frame-shaped reinforcement layer that surrounds and reinforces the electrolyte membrane. The reinforcement layer is typically electrically insulating and prevents a short circuit from occurring during operation of the electrochemical system 1.

[0054] In alternative embodiments, the system 1 can also be designed as an electrolyzer, an electrochemical compressor, or a redox flow battery. Separator plates 2 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 on or through the separator plates in an electrolyzer, an electrochemical compressor, or a redox flow battery can differ from the media used in a fuel cell system.

[0055] 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 can be flat surface planes of individual plates 2a, 2b (see Figure 2) from which a respective separator plate 2 is composed, or wherein the plate planes can run at least parallel to such flat surface planes. The plate planes or flat surface planes are aligned parallel to the xy plane and thus perpendicular to the stacking direction or to the z-axis 7. The end plate 4 generally has a plurality of media connections 5, via which media can be fed into the system 1 and via which media can be removed from the system 1, wherein the media connections 5 are sometimes referred to as ports. These media that can be fed into the system 1 and removed from the system 1 can, 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.

[0056] In an electrochemical system 1 as shown in Fig. 1, both known separator plates 2 according to the prior art and separator plates 2 according to the invention can be used.

[0057] Fig. 2 shows, in perspective, two adjacent separator plates 2 of an electrochemical system of the type of system 1 from Fig. 1, as well as a membrane electrode assembly (MEA) 10 known from the prior art and arranged between these adjacent separator plates 2, wherein the MEA 10 in 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, of which only the first individual plate 2a facing the viewer is visible in Fig. 2, which individual plate 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 together along their outer edge, e.g., by laser welding.

[0058] The individual plates 2a, 2b typically have aligned through-openings that form through-openings 11a-c of the separator plate 2. When a plurality of separator plates 2 are stacked, the through-openings 11a-c form lines that extend through the stack 6 in the stacking direction 7 (see Fig. 1). Typically, each of the lines formed by the through-openings 11a-c is in fluid communication with one of the ports 5 in the end plate 4 of the system 1. For example, coolant can be introduced into the stack 6 via the lines formed by the through-openings 11a, while the coolant is discharged from the stack 6 via other 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 with reaction gas and to discharge the reaction products from the stack 6.The media-carrying through-openings lla-c are essentially parallel to the plate plane.

[0059] 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 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 corresponding sealing beads on the rear side of the separator plates 2 facing away from the viewer of Fig. 2 for sealing the through-openings 11a-c (not shown). A bead arrangement 12 of the separator plate 2 can be understood as a combination of two interacting sealing beads 12a-c. More precisely, these can be sealing beads 12a of the individual plates 2a, 2b or sealing beads 12b of the individual plates 2a, 2b or sealing beads 12c of the individual plates 2a, 2b that point away from each other and are located on opposite sides of the separator plate 2.

[0060] However, a bead arrangement 12 within the meaning of this disclosure can also be formed by only one of the individual plates 2a, 2b having a sealing bead, for example in the form of one of the sealing beads 12a-c, while the corresponding other of the individual plates 2a, 2b opposite it does not have such a sealing bead 12a-c and is, for example, flat. In an electrochemically active region 18, the first individual plates 2a have, on their front side facing the viewer in Fig. 2, a flow field 17 with first structures 14 for guiding a reaction medium along the outer side (or front side) of the individual plate 2a. These first structures 14 are provided in Fig. 2 by a plurality of webs and channels extending between the webs and delimited by the webs. On the front side of the separator plate 2 facing the viewer in Fig. 2, the first individual plates 2a also each have a distribution and / or collection region 20.The distribution and / or collection region 20 comprises structures configured to distribute a medium introduced from a first of the two through-openings 11b into the adjacent distribution region 20 via the active region 18 and to collect or bundle a medium flowing from the active region 18 to the second of the through-openings 11b via the collection region 20. The distribution structures of the distribution and / or collection region 20 are also represented in Fig. 2 by webs and channels extending between the webs and delimited by the webs.

[0061] The sealing beads 12a-12c are crossed by passages 13a-13c, which are each formed in all individual plates 2a, 2b, and of which the passages 13a form a connection between the through opening 11a and the distribution area 20 both on the underside of the upper individual plate 2a and on the upper side of the lower individual plate 2b, while the passages 13b in the upper individual plate 2a and the passages 13c in the lower individual plate 2b establish a corresponding connection between the through opening 11b or 11c and the respectively adjacent distribution area 20. For example, the passages 13a allow a passage of coolant between the through-opening 11a and the distribution or collection area 20, so that the coolant enters or is led out of the distribution or collection area 20 between the individual plates 2a, 2b.

[0062] Furthermore, the feedthroughs 13b allow hydrogen to pass between the through-opening 11b and the distribution or collection area 20 on the upper side of the upper individual plate 2a. These feedthroughs 13b border openings 15 facing the distribution or collection area 20 and running obliquely to the plate plane. Hydrogen, for example, flows through the feedthroughs 13b and the openings 15 from the through-opening 11b to the distribution or collection area 20 on the upper side of the upper individual plate 2a or in the opposite direction. The feedthroughs 13c allow air, for example, to pass between the through-opening 11c and the distribution or collection area 20, so that air enters or is led out of the distribution or collection area 20 on the underside of the lower individual plate 2b. The corresponding openings running in the bead flank are not visible here.

[0063] As explained in more detail below, a respective passage 13a-c can be formed by at least one conducting channel and by openings in the bead flanks of a bead arrangement 12, so that, for example, a fluid path is formed which crosses a respective sealing bead 12a-c.

[0064] The first individual plates 2a further each have 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 / or collection region 20 and the through-openings 11b, 11c and seals them from the through-openings 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 12d. The structures of the active region 18, the distribution or collection structures of the distribution and / or collection region 20 and the sealing beads 12a-d are each formed integrally with the first individual plates 2a and molded into the individual plates 2a, e.g., in a stamping, hydroforming, or deep-drawing process. The same applies to the corresponding flow fields, distribution structures, and sealing beads of the second individual plates 2b.

[0065] Each sealing bead 12a-12d can have at least one bead top and two bead flanks in cross-section. However, a substantially angular arrangement between these elements is not necessary. A curved transition can also be provided, i.e., curved beads in cross-section are also possible.

[0066] While the sealing beads 12a-12c have a substantially rounded profile, which, however, primarily depends on the surface shape of the associated through-opening 11a-11c, the perimeter bead 12d has various sections with different shapes. Thus, the profile of the perimeter bead 12d can have at least two wave-shaped sections. With other shapes of the through-openings 11a-11c, profiles of the sealing beads 12a-12c can result in sections in which a wave-shaped sealing bead 12a-12c can also be used.

[0067] The two through-openings 11b or the lines formed by the through-openings 11b through the plate stack of system 1 are each in fluid communication with one another via the passages 13b crossing the sealing beads 12b, via the distribution structures of the distribution or collection area 20, and via the flow field 17 in the active area 18 of the first individual plates 2a facing the viewer in Fig. 2. Similarly, the two through-openings 11c or the lines formed by the through-openings 11c through the plate stack of system 1 are each in fluid communication with one another via corresponding line channels, via corresponding distribution structures, and via a corresponding flow field on an outer side of the second individual plates 2b facing away from the viewer in Fig. 2. For this purpose, channel structures 14 for guiding the respective media are provided in the active areas 18.

[0068] The through-openings 11a, however, or the lines formed by the through-openings 11a through the plate stack of the system 1, are each in fluid communication with one another via a cavity 19 enclosed or surrounded by the individual plates 2a, 2b. This cavity 19 serves to guide a coolant through the separator plate 2, in particular to cool the electrochemically active region 18 of the separator plate 2. The coolant thus primarily serves to cool the electrochemically active region 18 of the separator plate 2. The coolant flows through the cavity 19 from an inlet opening 11a towards an outlet opening 11a. Mixtures of water and antifreeze are often used as coolants. However, other coolants are also conceivable. To improve the guidance of the coolant or cooling medium, channel structures are provided on the inside of the separator plate 2. These are shown in Fig.2, since they run, for example, on the surface of the individual plate 2a facing away from the observer; they are thus opposite the above-mentioned channel structures 14 on the other surface of the individual plate 2a. In the active region 18, the channel structures guide the cooling medium along the inside of the separator plate 2 toward the outlet opening 11a.

[0069] While in Fig. 2 a separator plate 2 is shown in which the perimeter bead 12d does not enclose the through-openings 11a, ie the perimeter bead 12d is crossed by line channels of the feedthroughs 13a, designs of separator plates 2 are also possible in which the through-openings 11a, like the other through-openings 11b, 11c, are enclosed by the perimeter bead 12d, so that no such crossing is necessary.

[0070] Fig. 3 shows a section of a schematic separator plate 2 according to an example of the prior art, which, however, is designed largely analogously to the separator plates 2 explained with reference to Fig. 2. Reference is made here, by way of example but not limitation, to a through-opening 11, which may refer to one of the through-openings 11a-c from Fig. 2, in particular a through-opening corresponding to the through-opening 11b in Fig. 2. A position of the through-opening 11, which is not fully depicted, is marked with a corresponding reference symbol.

[0071] The individual plates 2a, 2b of the separator plate 2 from Fig. 3 touch each other in a plate plane E. This plate plane E coincides with the flat surface planes of the respective individual plates 2a, 2b. The first individual plate 2a can have a first sealing bead 20 arranged around the through-opening 11 for sealing the through-opening 11. Accordingly, the second individual plate 2b can have a second sealing bead 22 arranged around the through-opening 11 for sealing the through-opening 11. The first sealing bead 20 and the second sealing bead 22 form a bead arrangement 12 with a common bead interior 24, which is fluidically connected to the through-opening 11 of the individual plate 2. However, such a configuration of a bead arrangement 12 with or comprising two opposing sealing beads 20, 22 is purely optional.A bead arrangement 12 in the sense of the invention can also be formed, for example, in that only one of the sealing beads 20, 22 is present and a flat section of the corresponding other individual plate 2a, 2b is opposite this.

[0072] The first sealing bead 20 and the second sealing bead 22 are typically formed in opposing regions of the individual panels 2a, 2b and generally point away from each other with their bead tops 23. The first sealing bead 20 and the second sealing bead 22 are typically designed as solid beads and accordingly typically each comprise two bead flanks 26, 28, as shown. The bead flanks 26, 28 of the respective sealing beads are often connected to each other by a bead top 23, as shown.

[0073] The bead flanks 26 facing the through-opening 11 each have (i.e., in both individual plates 2a, 2b) a plurality of openings 30 in the form of raised portions 32. In the area of ​​these raised portions 32, the plate or flank material is not returned to a plate plane E, but remains at a distance therefrom, so that fluid can flow into and / or out of the bead interior 24. The openings 30 of the bead flanks 26 facing the through-opening 11 are each in fluid communication with the through-opening 11 via conduits 34 adjoining thereto and, more precisely, integrally formed thereon.

[0074] On the outer side of the bead arrangement 12 facing away from the through-opening 11, there are conduit channels 36. These, in turn, are in fluid communication with the bead interior 24 via openings 30 in the form of raised portions 32. The conduit channels 36 are designed here such that they open into a common distribution channel 38 running essentially parallel to the bead arrangement 12, which is also bead-shaped and on whose flank facing away from the bead arrangement 12 or the through-opening 11, openings 15 are arranged. A medium guided in the media channel of the through-opening 11 can thus be guided through the bead arrangement 12 via passages 30, wherein the passages 30 are formed by the line channels 34, the elevations 32 in the bead flanks 26, the bead interior 24, the elevations 32 in the opposite bead flanks 28, the line channels 36, the distribution channel 38 and the openings 15.In this way, the medium can be directed, for example, into the active area 18 of the individual plate 2a. A reversal of the flow direction occurs, for example, on the opposite side of the individual plate 2a, where the fluid is directed from the active area 18 through the bead arrangement 12 to the through-opening 11 (see Figure 2).

[0075] Figure 3 further shows that in this prior art solution, the conduits 34, 36 are opposite one another and each extend in a straight line along a longitudinal axis L. A width B of the respective conduits 34, 36 is constant, with the width B being measured transversely to the longitudinal axis L and parallel to the plate plane E. A height, measured orthogonally to the plate plane E, is also constant, resulting in a continuous, constant flow cross-section of the conduits 34, 36.

[0076] The separator plates 2 of the invention can, in particular in the area of ​​the feedthroughs 13, be designed in principle analogously to the example from Figure 3, with the exception of the designs of the line channels 34, 36 explained below.

[0077] Figure 4 shows a detailed view of an exemplary separator plate 2 according to the invention, as can be used in the embodiments of Figures 1 and 2. In principle, this separator plate 2 is designed analogously to the previously known example from Figure 3, so that essential differences from this previously known example are discussed here.

[0078] Shown is a section of a bead arrangement 12 in a top view of one of the individual plates 2a, 2a, whereby the correspondingly opposite individual plate 2a, 2b can be designed analogously in the section shown. The position of a through opening 11 is also indicated. TI

[0079] The bead arrangement 12 is merely exemplary and linear and extends along a longitudinal axis A. However, it can also be wave-shaped as in Figure 3 or have a different profile. A sealing bead 20 of the bead arrangement 12 facing the viewer in turn comprises a flank 26 facing the through-opening 11, which is a first flank within the meaning of this disclosure, and a flank 28 facing away from the through-opening 11, which is a second flank within the meaning of this disclosure. The flanks 26, 28 are in turn connected to one another via a bead roof 23.

[0080] Furthermore, the flanks 26, 28 each have a plurality of openings 30, one of which is visible in the section shown. The openings 30 can be formed as raised portions, but can also be configured differently.

[0081] Analogous to Figure 3, a conducting channel 34, 36 is formed on each of the openings 30. The conducting channels 34, 36 can be configured, for example, analogous to Figure 3 in their further course (not shown in Figure 4) and open into a distribution channel or an edge region of the through-opening 11. Variants are also possible in which the connection in the direction of the active region 18 of the individual plate 2a is designed without an additional distribution channel 38.

[0082] The conduits 34, 36 again extend along a longitudinal axis L and are located opposite one another. In particular, they are located opposite one another such that the respective longitudinal axes L coincide and orthogonally intersect a longitudinal axis A of the bead arrangement 12. Thus, a straight fluid path, which also runs orthogonally to the longitudinal axis L of the bead arrangement 12, is defined between the conduits 34, 36. Flow arrows S are shown in Figure 4, which show a flow path of the fluid from the through-opening 11 through the conduits 34, 36, crossing the bead arrangement 12.

[0083] In contrast to Figure 3, the conducting channels 34, 36 do not each have constant widths B. Instead, the widths decrease, at least in sections, with increasing proximity to the bead arrangement 12. In the example shown, this occurs equally and essentially linearly for both of the conducting channels 34, 36.

[0084] Figure 4 shows for each of the conducting channels 34, 36 a comparatively large width Bl in a channel section remote from the bead arrangement 12.

[0085] This width Bl decreases to a minimum width BO near the bead arrangement 12. The decrease occurs over a length X of a respective line channel 34, 36, which amounts to several millimeters and in particular more than half of the respective total length of the line channels 34, 36.

[0086] A location of the minimum width BO lies at a distance D from a respective adjacent flank 26, 28 or an opening 30 present there. This distance D is, for example, less than 1 mm. The minimum width BO can, for example, be less than half the initial width Bl or generally as a maximum width of a respective conduction channel 34, 36.

[0087] The conducting channels 34, 36 of Figure 4 each have a substantially constant height relative to the plane of the flat surface of the individual plate 2a. The height is measured perpendicular to the image plane. Any height variations are always smaller than the illustrated width variation, usually both in terms of relative dimensions and absolute dimensions. Consequently, the illustrated reduction in width of each conducting channel 34, 36 results in a reduction in the flow cross-section of the respective conducting channel 34, 36. The resulting cross-sectional narrowing toward the bead arrangement 12 leads to an acceleration of the flow through the conducting channels 34, 36 and when passing through the bead arrangement 12. It has been shown that this advantageously results in reduced pressure losses in the flow, which enables more efficient operation of the higher-level electrochemical system 1.Corresponding improvements can also be achieved if only one, and in particular the first line channel 34 closest to the through opening 11, has a correspondingly decreasing flow cross-section.

[0088] Figure 4 further indicates that the reduction in width and thus in the flow cross-section can be achieved, for example, by having opposing flanks 40, 42 of a respective duct 34, 36 extend at an angle W to each other that is less than 180°. For illustrative purposes, this angle W is shown only for one of the ducts 34, but is also present for the corresponding other duct 36.

[0089] Figure 4 shows an exemplary case in which the conduit channels 34, 36 are essentially identically dimensioned. Figure 5 shows a further exemplary embodiment in a representation analogous to Figure 4. In this case, the conduit channels 34, 36 are not identically dimensioned. Instead, the conduit channel 34 closer to the through-opening 11 has a smaller width Bl away from the bead arrangement 12 than the corresponding other conduit channels 36. In both cases, however, the corresponding distant width Bl decreases with increasing proximity to the bead arrangement 12 to a reduced width BO, which in turn results in a corresponding reduction in the flow cross-section.

[0090] Figures 6-9 show further exemplary embodiments of the invention. They again show plan views of one of the individual plates 2a, whereby the correspondingly opposite individual plate 2b can be designed analogously. The section of the individual plate 2a shown in each case is similar to that in Figure 3. The position of a feedthrough opening 11 is marked in each case.

[0091] In Figures 6 and 7, the bead arrangement 12 is shown as an example with a wave-shaped profile. This wave-shaped profile extends along a longitudinal axis A, which defines a main direction of extension and is overlaid by the wave shape. The bead arrangement 12 is again pierced by several openings 30 in its flanks 26, 28 on both sides, with conducting channels 34, 36 being integrally formed on the openings 30.

[0092] In Figure 6, in contrast to Figures 4 and 5, only the line channels 34 on one side of the bead arrangement 12 facing the through-opening 11 have a reduced flow cross-section. This is achieved analogously to Figures 4 and 5, again by a decrease in width at a constant height, and more precisely by an initially increased width Bl and a minimum width B0 near the bead arrangement 12. The line channels 36 on the side facing away from the through-opening 11, in contrast, have a constant width B. As previously mentioned, however, pressure losses can also be reduced in this case when the medium is passed from the through-opening 11 into the distribution area or active area of ​​the individual plate 2a (not shown in these figures).

[0093] In Figure 7, the conducting channels 34, 36 on both sides of the bead arrangement 12 have width variations analogous to Figures 4 and 5.

[0094] In Figures 8 and 9, the bead arrangement 12 is shown as an example with a straight line. Figure 8 shows an example analogous to Figure 4, according to which essentially similarly dimensioned conduits 34, 36, which also have similar width variations, are arranged opposite one another on the two sides of the bead arrangement 12.

[0095] Figure 9, however, shows the case in which bilateral conduit channels 34, 36, dimensioned analogously to Figure 8, are not directly opposite one another. A fluid passing from the conduit channels 34 near the through-opening 11 via the bead interior 24 into the conduit channels 36 facing away from the through-opening 11 therefore follows a non-rectilinear fluid path F, as indicated in Figure 9. However, due to the reduction in flow cross-section near the bead arrangement 12 achieved by means of the width variation, pressure losses of the fluid as it passes through the bead arrangement 12 can still be reduced.

[0096] While Figure 6 shows an example of a media guide in which the medium is guided from the through-opening 11 in the direction of the distribution area or active area without further openings 15, i.e. there can either be an opening on the lower individual plate covered by the upper individual plate so that gas can be guided to the lower outer side of the lower individual plate, or there is no opening at all so that cooling medium can be guided from the through-opening into the space between the individual plates, Figures 7-9 each show example openings 15 which can serve to guide the gas to the outer side of the upper individual plate. The arrangement of the openings 15 is exemplary here, however; the inventive design of the openings and line channels can be used for all media.

Claims

1. Separator plate (2) for an electrochemical system (1), comprising: - at least one through-opening (11) for forming a media channel for media supply or media discharge, and - at least one bead arrangement (12) arranged around the at least one through-opening (11) for sealing the through-opening (11), wherein the bead arrangement (12) has a first flank (26) facing the through-opening (11) and a second flank (28) facing away from the through-opening (11), wherein the first flank (26) has a plurality of first openings (30) and the second flank has a plurality of second openings (30), wherein a first line channel (34) is connected to each of the first openings (30) and is in fluid communication with the through-opening (11), wherein at least one of the first line channels (34) has a flow cross-section that decreases at least in sections in the direction of the first opening (30).

2. Separator plate (2) according to claim 1, wherein a second line channel (36) is connected to each of the second openings (30), wherein at least one of the second line channels (36) has a flow cross-section which decreases at least in sections in the direction of the second opening (30).

3. Separator plate (2) according to claim 2, wherein the at least one first conduit channel (34) and the at least one second conduit channel (36), each having a decreasing flow cross-section, are connected to one another by a substantially rectilinear fluid path.

4. Separator plate (2) according to claim 3, wherein the fluid path runs at an angle of at least 60° and in particular substantially orthogonal to a longitudinal axis (A) of the bead arrangement (12).

5. Separator plate (2) according to one of the preceding claims, wherein at least a quarter, at least half, at least three-quarters or all of the first line channels (34) and / or the second line channels (36) according to claim 2 have a flow cross-section which decreases at least in sections in the direction of a respective adjoining first or second opening (30).

6. Separator plate (2) according to one of the preceding claims, wherein a flow cross-section of the at least one first line channel (34) is minimal at a distance of less than 5 mm, in particular less than 2 mm, from the first opening (30), and / or wherein the separator plate (2) has the at least one second line channel (36) according to claim 2 and a flow cross-section of this one second line channel (36) is minimal at a distance of less than 5 mm, in particular less than 2 mm, from the second opening (30).

7. Separator plate (2) according to one of the preceding claims, wherein the flow cross-section of the at least one first conduit channel (34) over a length (X) of at least one quarter or at least the Half of a total length of the first line channel (34), and / or wherein the separator plate (2) has the at least one second line channel (36) according to claim 2 and whose flow cross-section decreases over a length (X) of at least a quarter or at least half of a total length of the second line channel (36).

8. Separator plate (2) according to one of the preceding claims, wherein the at least one first conducting channel (34) has a constant height or a change in the height along its length is less than a change in a width (B) of the first conducting channel, and / or wherein the separator plate (2) has the at least one second conducting channel (36) according to claim 2 and this has a constant height or a change in the height along its length is less than a change in a width (B) of the second conducting channel (36).

9. Separator plate (2) according to one of the preceding claims, wherein the decrease in the flow cross-section over a length of 1 mm is a maximum of 30%, preferably a maximum of 25%, and / or wherein the separator plate (2) has the at least one second conduit channel (36) according to claim 2 and the decrease in its flow cross-section over a length of 1 mm is a maximum of 30%, preferably a maximum of 25%.

10. Separator plate (2) according to one of the preceding claims, wherein the first conducting channel (34) has a first flank (40) and a second flank (42) which extend at least partially at an angle (W) of less than 180° and in particular less than 140° to one another, reducing the flow cross-section; and / or wherein the separator plate (2) has the at least one second conducting channel (36) according to claim 2 and this has a first flank (40) and second flank (42) which extend at an angle (W) of less than 180° and in particular less than 140° to each other, reducing the flow cross-section. (Fig. 4)

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