DE202015106197U1 - Separator plate for an electrochemical system and electrochemical system - Google Patents

Abstract

Separator plate (10) for an electrochemical system (1) with two individual plates (10 ', 10' ') and a cavity (18) arranged between the individual plates for carrying out a cooling medium, wherein at least one of the individual plates has an active region (16', 16 '') having structures (17 ', 17' ') for guiding a reaction medium on an outer side of the separator plate (10) and a bead (15', 15 ''), which for sealing the active area or for sealing an opening ( 10c, 10g) is formed in the separator plate (10), wherein the opening (10c, 10g) for supplying a cooling medium into the cavity (18) or for discharging a cooling medium from the cavity (18) is formed, and wherein the bead ( 15 ', 15' ') has at least one lowered portion (31', 31 '') in which the height (20 ', 20' ') of the sock roof (23', 23 '') is smaller than that along the course the bead (15 ', 15' ') determines the average height of the Sick roofs (23 ', 23' '); characterized in that a minimum height of the bead roof (23 ', 23' ') in the lowered area (31', 31 '') to reduce a coolant flow in the bead interior (24) is less than or equal to a maximum height (22 ', 22' ' ) of the structures (17 ', 17' ') of the active region (16', 16 '').

Description

The present invention relates to a separator plate for an electrochemical system and to an electrochemical system having a plurality of separator plates of the type proposed here. The electrochemical system may be, for example, a fuel cell system, an electrochemical compressor, an electrolyzer or a humidifier for a fuel cell system , The humidifier is also considered as an electrochemical system.

Known electrochemical systems usually comprise a multiplicity of separator plates, which are arranged in a stack, so that between each two adjacent separator plates an electrochemical cell or a humidifier cell is arranged. The separator plates usually each comprise two individual plates which are connected to one another along their rear sides remote from the electrochemical cells or the humidifier cells.

The Separatorplatten can z. B. the electrical contacting of the electrodes of the individual electrochemical cells (eg., Fuel cells or electrolysers) and / or the electrical connection of adjacent cells are used (series connection of the cells). The separator plates may also be configured to dissipate heat generated in the cells between the separator plates. Such waste heat can occur, for example, in the conversion of electrical or chemical energy in an electrolyzer or a fuel cell. In fuel cells, bipolar plates are frequently used as separator plates. The separator plates may also be configured to supply the cells with media, e.g. As with reaction gases, supply and transport away reaction products from the cells. For this purpose, the separator plates can have channel structures, which are arranged in particular in an electrochemically active area (gas distributor structure / flow field). The active area may, for. B. include or limit an electrochemical cell or a humidifier cell. The channel structures may, for. B. molded into the individual plates, in particular stamped.

The individual plates of the separator plates are normally connected together so as to enclose between them a cavity for passing a cooling medium. In particular, the cooling medium serves to dissipate heat from the active region of the separator plate or the individual plates.

Usually, the separator plates or the individual plates of the separator plates each have at least one passage opening. In the separator plate stack of the electrochemical system, the passage openings of the stacked separator plates which are aligned or at least partially overlapping, then form media channels for supplying media or for discharging media. These through-holes or the media channels formed by the through-holes usually each provide a fluid connection between the active region on the outside of the separator plate or between the cavity for passing a coolant and a port on an end plate of the electrochemical system. A medium can then be introduced into the system or removed from the system via such a port.

For sealing the passage openings or the media channels formed by the passage openings of the separator plates and / or for sealing the active area, known separator plates may further comprise bead arrangements which are respectively arranged around the passage opening and / or around the active area of the separator plate. The bead arrangements can also be molded into the individual plates, in particular impressed.

It has been shown in individual cases that the cooling medium is guided in the cavity between the individual plates of the separator plate in undesirable ways. Sometimes the cooling medium z. B. to a considerable extent flow through the region of the embossed bead and so are guided past the cavity facing the rear side of the active region of the separator plate, which at least in places can lead to insufficient cooling of the active area. This can adversely affect the efficiency of the electrochemical system.

It is therefore an object of the present invention to provide a separator plate for an electrochemical system, which allows operation of the electrochemical system with the highest possible efficiency.

This object is achieved by a separator plate according to claim 1. Special embodiments are described in the subclaims.

So proposed is a Separatorplatte for an electrochemical system with two individual plates and arranged between the individual plates cavity for performing a cooling medium. At least one of the individual plates has an active area with structures for guiding a reaction medium on an outer side of the separator plate and a bead, which is designed to seal the active area or to seal an opening in the separator plate, wherein the opening is formed for supplying a cooling medium into the cavity or for discharging a cooling medium from the cavity. The bead has at least one lowered region in which the height of the bead roof is smaller than the average height of the bead cover along the course of the bead. With the average height of the beaded roof along the course of the bead, the mean greatest height of the beaded roof over the connecting plane of the individual plates in the regions in which the beaded roof runs parallel to this connecting plane should be designated here.

The proposed Separatorplatte is characterized in that a certain perpendicular to the plane surface plane of the respective individual plate minimum height of the sill roof in the lowered area to reduce coolant flow in the bead interior is less than or equal to a also perpendicular to the planar plane of the single plate maximum height of the structures of the active area.

Because the minimum height of the beaded roof in the lowered region of the bead is less than or equal to the maximum height of the structures of the active region, the cooling medium is largely or completely prevented from passing past the rear side of the active region of the separator plate through the beaded interior, where it does not or only to a small extent contribute to the cooling of the active area of the separator plate and / or to the cooling of the electrochemical cell or humidifier cell bounded by the active area. Compared to known separator plates, the separator plate proposed here thus enables a more efficient cooling of the system. Thus, the temperature distribution of the system can be set better and with less energy and the efficiency of the system can be significantly increased. Compared with other solutions that provide to reduce or avoid the flow of coolant in the bead interior, the introduction of an additional filling element in the bead interior, the solution proposed here has the further advantage that it can be realized without the introduction of such an additional filler element. The separator plate proposed here is therefore also particularly easy and inexpensive to produce.

The structures for guiding a reaction medium on the outside of the separator plate may include channel structures in the active area of the separator plate. The maximum height of these structures, which is determined perpendicular to the planar surface plane of the respective individual plate, can thus be in particular a maximum height or a maximum depth of these channel structures.

The bead can be lowered in the lowered area over the entire width of the bead. As a result, the undesired flow of the coolant in the bead interior can be further reduced. In addition, a lowered over the entire width bead during manufacture is typically particularly easy to shape.

The bead may also be lowered in the lowered area only over part of the width of the bead or have a different degree of reduction along the width of the bead. For example, a rounded bead can be lowered so that a wide plateau is formed. This also makes it possible to effectively reduce the hydraulic cross section of the bead interior.

For particularly efficient suppression or reduction of the coolant flow in the interior of the bead, the minimum height of the sock roof in the lowered area, which is perpendicular to the planar surface plane of the respective individual panel, can be at most 50 percent, preferably at most 25 percent, particularly preferably at most 10 percent, of the mean height of the sicke along the course of the sipe Sick roofs amount. Alternatively or additionally, the minimum height of the bead cover in the lowered region can amount to at most 90 percent, preferably at most 60 percent, particularly preferably at most 20 percent, of the maximum height of the structures of the active region. The beaded roof can also be lowered in the lowered area to the planar surface plane of the respective individual panel, in particular over the entire width of the bead. Likewise, the lowered portion of the bead may be formed such that a cross section of the bead interior in the depressed area is at most 50 percent, preferably at most 25 percent, particularly preferably at most 10 percent of the average bead cross section along the course of the bead.

The lowered region may extend along the direction of the bead over a length which is at least three times, preferably at least five times, a foot width of the bead determined transversely to the longitudinal direction of the bead, in particular with respect to an average foot width determined by averaging along the course of the bead. This can contribute to the bead having a high degree of elasticity even in the lowered area. On the other hand, a contiguous lowered portion of a bead will advantageously never be more than a quarter of the total length of the respective bead.

The maximum height of the bead may be at least one-and-a-half, preferably at least twice, more preferably at least three times the maximum height of the structures of the active area. If the bead is designed to seal the active region and circumscribes the active region, then a membrane composite of sufficient thickness can be accommodated in the active region and the space surrounding the membrane composite can be sealed to the outside by the bead.

The bead can additionally have at least one raised area in which the height of the beaded roof is greater than the average height of the beaded roof along the course of the beading. For example, the maximum height of the sock roof in the raised area may be at least 1.3 times, preferably at least 1.5 times, in particular 1.75 times, the mean height of the sock roof along the course of the sipe. In particular, the bead can have at least two lowered areas and an identical number of raised areas to the number of lowered areas. Preferably, the lowered portions of the bead are disposed on opposite sides of the bead path, which typically forms a closed curve. Is the bead z. B. formed for sealing the active area, so is ensured by the arrangement of the depressed area on both sides of the active area that the undesired flow of coolant through the bead interior on both sides of the active area is reduced or prevented.

The central bead cross section is preferably not determined over the entire course of the bead, but preferably only along such areas in which a) the bead is neither lowered nor increased, i. in which the bead height corresponds to the average bead height, and b) the bead has no openings in the flanks. Here, if the bead has straight sections, only those sections are considered in which the bead is straight and the conditions a) and b) apply. If the bead has no straight sections, but has a wave-shaped course, only the cross sections are taken into account at the turning points, where the conditions a) and b) apply.

The lowered area of the bead and the raised area of the bead or the lowered areas of the bead and the raised areas of the bead can in particular be arranged and configured such that in the formation of the separator plate stack the bead of a separator plate seals with a bead of a structurally identical further separator plate can be brought into engagement, for. B. in particular such that the raised portion or the raised portions of the bead of a first separator plate is positively received in the lowered area or in the lowered areas of the bead of one of the first separator plate adjacent, identical second separator plate or are added. For this purpose, the raised area or the raised areas of the bead are preferably designed to be complementary to the lowered area or to the lowered areas of the bead.

Preferably, the lowered and the raised portions of the bead are formed such that an edge region of a membrane electrode assembly (MEA) arranged between the separator plates can be arranged and pressed between the beads of adjacent, identical separator plates, in particular also in the lowered and the raised areas of the beads. In an electrochemical system with a stack of separator plates designed in this way, the mutually facing beads of adjacent, identically constructed separator plates engage one another in a form-fitting manner along the complementary raised and lowered regions. As a result, the stability of the separator plate stack, in particular with respect to displacements perpendicular to the stacking direction, can be significantly increased.

In the active region surrounded by the beads of the adjacent separator plates, the MEA arranged between the separator plates typically has a membrane composite. This membrane composite usually comprises at least one polymer electrolyte membrane (PEM) and gas diffusion layers (GDL). The GDL can be arranged on both sides of the PEM and be designed, for example, as a carbon nonwoven. In the case of a fuel cell stack, the membrane composite may comprise electrochemically active electrodes. These are usually arranged on both sides of the PEM. The can be arranged between the beads and compressible edge area of the MEA, however, z. B. only the edge of the PEM of the membrane composite and no GDL. Alternatively, the edge region of the MEA may comprise a reinforcement, which is attached to the membrane composite and surrounding the membrane composite circumferentially. It is likewise conceivable that the edge region of the MEA has both the edge of the PEM and also a reinforcement, wherein the edge of the PEM and the reinforcement in the edge region of the MEA are then z. B. are joined together to form a laminate. Preferably, the edge region of the MEA has a smaller thickness than the membrane composite bordered by the edge region of the MEA.

The bead can be curved at least partially in the lowered and / or in the raised portion of the bead, z. B. along the course of the bead and / or across the course of the bead. The beaded roof preferably has no edges in the lowered and / or elevated region, in particular along the course of the bead. This contributes to maintaining the elasticity of the bead in the lowered and / or elevated area. moreover For example, edges formed in the lowered and / or raised region of the bead could damage a marginal area of an MEA arranged between the adjacent separator plates and be arranged between the beads of adjacent separator plates. The MEA and the edge region can be designed as described above. This can be avoided by the configuration of the lowered and / or elevated area without edges.

To increase the stability and the elasticity of the bead, the bead may at least partially extend undulating and have a wavelength λ. The lowered area of the bead and / or the raised area of the bead can then extend along the course of the bead over a length of at least λ, preferably at least 2 · λ. If the lowered and / or the raised areas are wave-shaped, the wave amplitude and / or the wavelength in the raised and / or lowered regions may deviate from the wave amplitude and / or the wavelength in the non-raised or lowered regions of the bead. However, the lowered and / or elevated regions can also run completely or at least partially straight, in particular even if the bead otherwise has wave-shaped regions.

The individual plates of the separator plate may be formed of metal, preferably of stainless steel. Alternatively, other metals suitable for corresponding electrochemical systems, such as e.g. Titanium or aluminum, as well as coated steels are used. A thickness of the individual plates, which is determined perpendicular to the plane of the plane of the individual plates, can be between 50 μm and 150 μm, preferably between 70 μm and 110 μm. The bead and the structures of the active area can be embossed in the single plate or in the individual plates.

Preferably, both individual plates each have an active area with structures for guiding a reaction medium on an outer side of the separator plate and at least one bead having at least one lowered area and preferably additionally having at least one raised area. The lowered and / or the raised region of the beads of both individual plates can then each be formed as described above and stamped analogously into the separator plate.

If the beads of both individual plates each have at least two lowered regions and two raised regions of the previously described type, the lowered regions and the raised regions can be arranged symmetrically with respect to an axis of symmetry of the separator plate. The axis of symmetry may be aligned perpendicular or parallel to the plane planes of the individual plates. For example, the separator plate may have a twofold rotational symmetry with respect to the axis of symmetry. If this is the case, the separator plate stack of an electrochemical system can be formed from a multiplicity of identically constructed separator plates, the lowered and raised regions of the mutually facing beads of adjacent separator plates of the stack interlocking in a form-fitting manner as described above. Identical adjacent separator plates of the stack are then typically rotated 180 degrees relative to one another.

Further proposed is an electrochemical system, in particular a fuel cell system, an electrochemical compressor, a humidifier for a fuel cell system or an electrolyzer, with a layer of cells, each having at least one membrane composite with at least one polymer membrane. The cells are each separated by separator plates of the type described above.

Adjacent to each other Separatorplatten the proposed electrochemical system have mutually facing beads, each having at least one lowered portion and each having at least one elevated portion, wherein the lowered portions and the raised portions in the mutually facing beads are arranged so complementary to each other and formed that the facing each other beads are sealingly engaged with each other, preferably receiving the edge portion of an MEA, which is arranged between the adjacent Separatorplatten.

The mutually facing beads can be increased in the raised regions relative to the mean height of the beaded roof along the course of the respective beading by at least an amount corresponding to a thickness of the membrane composite in the compressed state disposed between the structures of the active region of adjacent separator plates. Preferably, the mutually facing beads of the adjacent Separatorplatten in the lowered areas are then lowered by a nämlichen amount. The proposed electrochemical system may, in particular, have a multiplicity of identically constructed separator plates of the type described above.

The cooling medium here is not exclusive to be understood as a coolant. It can also be used to warm up the electrochemical system under certain operating conditions. The cooling medium can be liquid or be gaseous or present as a liquid-gaseous two-phase system.

Specific embodiments of the invention are illustrated in the figures and will be explained in more detail with reference to the following description. It shows:

1 in perspective, a fuel cell system with a plurality of stacked Separatorplatten, in particular bipolar plates;

2 in perspective, two separator plates of the stack according to 1 with a membrane composite arranged between the separator plates;

3 two adjacent Separatorplatten the stack according to 1 in a sectional view;

4a . 4c a sectional view and a side view of the stack according to 1 ;

4b a plan view of one of the separator plates of the stack according to 1 ;

4d further sectional views of the stack according to 1 , wherein the sectional plane perpendicular to the sectional plane of the 4a . 4c stands;

5a . 5c a sectional view and a side view of the stack according to 1 ;

5b the top view of one of the separator plates of the stack according to 4b additionally showing part of an active area of the separator plate;

5d the sectional views of the stack according to 4d additionally showing parts of an active area of the separator plates;

6a -B enlarged views of sectional views according to 5d ;

7a -C enlarged views of the sectional views according to 5d , wherein in each case a membrane composite is arranged between adjacent separator plates;

8th a plan view of an embodiment of one of the separator plates of the stack according to 1 ;

9 a plan view of another embodiment of one of the separator plates of the stack according to 1 ;

10a a plan view of an embodiment of a bead of one of the separator plates of the stack according to 1 ; and

10b a plan view of another embodiment of a bead of one of the separator plates of the stack according to 1 ,

1 shows an inventive electrochemical system 1 with a pile 2 of several identically constructed separator plates running along a z-direction 7 stacked and between two end plates 3 . 4 are clamped. The separator plates are designed here as bipolar plates and each comprise two interconnected individual plates. In the present example, the system is 1 around a fuel cell stack. Two adjacent bipolar plates of the stack 2 So include between them an electrochemical cell, which is designed to convert chemical energy into electrical energy. In alternative embodiments, the system 1 also be designed as an electrolyzer, electrochemical compressor or as a humidifier for a fuel cell system. Separator plates are also used in these electrochemical systems. The structure of these separator plates corresponds to the structure of the bipolar plates explained in more detail here, even if the media guided onto or through the separator plates differ.

The z-axis 7 clamps together with an x-axis 8th and a y-axis 9 a right-handed Cartesian coordinate system. The end plate 4 has a variety of ports 5 on, over the system 1 Media feedable and via the media from the system 1 are deductible. This the system 1 feedable and out of the system 1 Abführbaren media can z. As fuels such as molecular hydrogen or methanol, reaction gases such as air or oxygen, reaction products such as water vapor or oxygen-depleted air, or coolant such as water, water vapor and / or water-glycol mixtures.

2 shows two immediately adjacent Separatorplatten 10 . 11 of the pile 2 out 1 , Here and in the following, recurring features are denoted by the same reference numerals. The separator plates 10 . 11 are identical. In the following, therefore, only the separator plate 10 described in detail. It is thus an example of the separator plates of the stack 2 ,

The plane planes of the individual plates of the separator plate 10 are aligned along the xy plane. Here is the separator plate 10 from two assembled metallic single plates 10 ' . 10 '' educated. In 2 However, only the viewer facing first single plate 10 ' the separator plate 10 visible, noticeable. The single plates 10 ' . 10 '' the separator plate 10 are made of stainless steel sheets, the z. B. each have a perpendicular to the plane surface plane of the individual plates certain thickness of 100 microns. The single plates 10 ' . 10 '' can be used to form the separator plate 10 welded together along their mutually facing backs, in particular welded together in sections, be soldered or glued. For example, the single plates 10 ' . 10 '' be connected by laser welding connections.

Between the separator plates 10 . 11 is a membrane electrode assembly (MEA) 12 arranged. The MEA 12 may comprise a membrane composite with a polymer electrolyte membrane (PEM) and with one or more gas diffusion layers (GDL). The GDL are usually to the separator plates 10 . 11 oriented and z. B. formed as a carbon fabric. Furthermore, the MEA 12 have an edge region which the membrane composite of the MEA 12 surrounds circumferentially. The facing sides of the separator plates 10 . 11 close in the pressed state an electrochemical cell 13 one. In humidifiers for fuel cell systems, the cell includes 13 a substantially gas impermeable but water permeable membrane which may be supported by support media. In the case of humidifiers, at least one layer of a diffusion medium is typically further arranged on both sides of the membrane. The diffusion medium may, for. B. include a textile or a carbon fabric.

The separator plate 10 has a plurality of through holes 10a -H, up. The MEA 12 has corresponding passage openings, with the through holes 10a -H the separator plate 10 and with corresponding through openings of the remaining separator plates of the stack 2 aligned so that the through holes after pressing the stack 2 Form media channels, each with one of the ports 5 out 1 are in fluid communication. These media channels serve to supply media to the electrochemical system 1 and the discharge of media from the electrochemical system 1 ,

For sealing the passage openings 10a -H or for sealing of the through holes 10a -H formed media channels are in the Separatorplatte 10 Beading arrangements formed around the through holes 10a -H are arranged around. So has the separator plate 11 remote first single plate 10 ' the separator plate 10 around the passages 10a -H around beading arrangements 14a ' - 14h ' on. The bead arrangements 14a ' - 14h ' enclose the passage openings 10a -H in each case completely. The separator plate 11 facing and in 2 concealed second single plate 10 '' the separator plate 10 points around the passage openings 10a -H around corresponding bead assemblies. An additional bead arrangement 15 ' the separator plate 10 encloses the passage openings 10a -b, 10d -F and 10h together and together with the area of the structure 17 ' Completely.

The bead arrangements of the separator plate 10 are here in each case in one piece with the single plates 10 ' . 10 '' educated. Usually, the bead arrangements of the individual plates 10 ' . 10 '' formed in the individual plates, in particular embossed. Perpendicular to the planar surface plane of the individual plates 10 ' . 10 '' have the formed in the individual plates bead assemblies in the unpressed state each have a height of only 500 microns or even only 450 microns. The height of the bead in each case designates the distance of the highest point of the sipe roof to the planar surface plane of the respective single plate on the surface facing the sock roof. This extraordinarily small bead height advantageously contributes to the compactness of the stack 2 of the system 1 at.

In 2 It can also be seen that the first single plate 10 ' the separator plate 10 at her from the second single plate 10 '' the separator plate 10 facing away from front in an approximately rectangular active area 16 ' a structure 17 ' for guiding reaction medium. The structure 17 ' includes a variety of channels that fit into the single plate 10 ' are impressed. The structure 17 ' is also called flowfield or gas distribution structure. The active area 16 ' the separator plate 10 or the first single plate 10 ' the separator plate 10 delimits another electrochemical cell, which is between the separator plate 10 and one of the separator plate 10 in the positive z-direction 7 is arranged immediately adjacent another separator plate, the in 2 not shown. The active area 16 ' and the structure 17 ' are on all sides completely from the bead arrangement 15 ' enclosed, so that the bead arrangement 15 ' the active area 16 ' and the structure 17 ' seals against the environment. The second single plate 10 '' the separator plate 10 indicates its from the first single plate 10 ' front side facing away from the active area 16 ' corresponding active area 16 '' and one of the structure 17 ' corresponding, in the second single plate 10 '' embossed structure 17 '' for conducting reaction medium (see 3 ).

The single plates 10 ' . 10 '' the separator plate 10 are formed and arranged such that they form a cavity between their mutually facing rear sides 18 to carry out a cooling medium. In the cooling medium, it may, for. B. to act water-glycol mixtures. The cavity 18 is particularly so between the individual plates 10 ' . 10 '' arranged by means of the through the cavity 18 guided coolant heat from the active areas of the individual plates 10 ' . 10 '' is derivable.

The single plates 10 ' . 10 '' also have bushings 19a For metering or passing media (eg, fuels, reaction gases, reaction products, or coolant) through the bead assemblies 14a ' - 14h ' . 15 ' are formed. Some of the executions 19a -H, namely the bushings 19c and 19g , provide fluid communication between the ports 10c and 10g (or the media channels formed by them) and the cavity 18 between the single plates 10 ' . 10 '' ago. Some of the bushings, namely the bushings 19a and 19e , provide fluid communication between the ports 10a and 10e (or the media channels formed by them) and the structures 17 ' of the viewer the 2 facing active area 16 ' the first single plate 10 ' ago. The remaining bushings 19b . 19d . 19f and 19h provide fluid communication between the ports 10b . 10d . 10f and 10h (or the media channels formed by them) and the structures facing away from the viewer 17 '' of the active area 16 '' the second single plate 10 '' ago.

3 shows a schematic representation of a yz section of the separator plates 10 . 11 with the single plates 10 ' . 10 '' . 11 ' . 11 '' and between the separator plates 10 . 11 arranged MEA 12 , Shown are the bead 15 ' and the active area 16 ' the first single plate 10 ' , A beaded roof 23 ' the bead 15 ' has a height 20 ' , The height 20 ' the beaded roof 23 ' is by the perpendicular to the plane plane of the single plate 10 ' , here along the z-direction 7 certain distance of the sill roof 23 ' from the planar surface plane of the single plate 10 ' given. The one of the structures 17 ' of the active area 16 ' formed channels have a maximum height 22 ' , The maximum height 22 ' the structures 17 ' is by the perpendicular to the plane plane of the single plate 10 ' certain distance of the tops of the structures 17 ' from the planar surface plane of the single plate 10 ' given.

In 3 is the height 20 ' z. B. equal to the along the course of the bead 15 ' certain mean height of the sill roof 23 ' and is at least one and a half times, preferably at least twice the maximum height 22 ' the structures 17 ' of the active area 16 ' the first single plate 10 ' the separator plate 10 , The mean height of the bead 15 ' or the sock roof 23 ' is preferably less than 500 microns, z. B. 440 microns. The maximum height 22 ' the one of the structures 17 ' formed channels can, for. B. 240 microns.

Shown are in 3 also the bead 15 ' 'and the active area 16 '' the second single plate 10 '' , A beaded roof 23 '' the bead 15 '' has a height 20 '' , The height 20 '' the beaded roof 23 '' is by the perpendicular to the plane plane of the single plate 10 '' , here along the z-direction 7 certain distance of the sill roof 23 '' from the planar surface plane of the single plate 10 '' given. The one of the structures 17 '' of the active area 16 '' formed channels have a maximum height 22 '' , The maximum height 22 '' the structures 17 '' is by the perpendicular to the plane plane of the single plate 10 '' certain distance of the tops of the structures 17 '' from the planar surface plane of the single plate 10 '' given.

In 3 is the height 20 '' z. B. equal to the along the course of the bead 15 '' certain mean height of the sill roof 23 '' and is at least one and a half times, preferably at least twice the maximum height 22 '' the structures 17 '' of the active area 16 '' the second single plate 10 '' the separator plate 10 , The mean height of the bead 15 '' or the sock roof 23 '' is preferably less than 500 microns, z. B. 440μm. The maximum height 22 '' the one of the structures 17 '' formed channels can, for. B. 300 microns.

To seal the active areas 16 ' . 16 '' around the active areas 16 ' . 16 '' arranged around beads 15 ' . 15 '' the two single plates 10 ' . 10 '' close a beading interior 24 a, the z. B. partially in fluid communication with the cavity 18 for passing a coolant between the individual plates 10 ' . 10 '' can be. For example, it is not always avoidable for coolant to pass through the opening 10c in the separator plate 10 in the cavity 18 and that is about the opening 10g in the separator plate 10 from the cavity 18 is derived (see 2 ), sometimes in the bead interior 24 gets where it is needed to cool the active areas 16 ' . 16 '' the single plates 10 ' . 10 '' not or virtually does not contribute. For the most efficient cooling of the active areas 16 ' . 16 '' should therefore be avoided as possible, that coolant in the cavity 18 at the active areas 16 ' . 16 '' past the bead interior 24 in the area of the beads 15 ' . 15 '' from the opening 10c to the opening 10g flows. In particular in connection with the 4 - 7 described embodiment of the beads 15 ' . 15 '' should therefore contribute to a coolant flow in the bead interior 24 reduce or completely eliminate it.

The MEA 12 can be a polymer membrane 25 and on both sides of the polymer membrane 25 arranged gas diffusion layers (GDL) 26 ' . 26 '' exhibit. The polymer membrane 25 and the GDL 26 ' . 26 '' form a membrane composite. This membrane composite is in the active area 16 '' the second single plate 10 '' and a corresponding active area of the single plate 11 ' the separator plate 11 taken up and between the Separatorplatten 10 . 11 arranged. The membrane composite is from the beads 15 '' . 27 ' enclosed and is from the beads 15 '' . 27 ' sealed. An outer edge of the polymer membrane 25 (eg, an electrolyte membrane) forms an edge region of the MEA 12 and is between the beads 15 '' and 27 ' the single plates 10 '' and 11 ' arranged and pressed. In other embodiments, instead of the outer edge of the polymer membrane 25 also one from the polymer membrane 25 different and with the membrane composite of the MEA 12 connected reinforcing edge between the beads 15 '' and 27 ' be pressed. The membrane composite of the MEA 12 has a thickness determined perpendicular to the planar surface plane of the membrane composite 27 from Z. B. 290 microns. The fat 27 the membrane composite can, for. B. 0.5 to 1.5 times the maximum height 22 '' the structures 17 '' be. The planar surfaces of the membrane composite and separator plates 10 . 11 are aligned parallel to each other, here in each case parallel to the xy-plane.

The 4a and 4c show an xz-section through or a side view of a part of the stack 2 according to 1 , ie perpendicular to the plane planes of the separator plates of the stack 2 , In the 4b emphasized sectional plane AA extends in the longitudinal direction through the arranged to seal the active areas of the separator around the active areas of the separator around beads, especially in the longitudinal direction through the beads 15 ' . 15 '' the single plates 10 ' . 10 '' according to the 2 and 3 , The 4a -C point along the x-direction 8th each same section of the stack 2 , 4d shows several yz cuts through the same part of the stack, each along the in 4b highlighted section planes BB, CC and DD. 4b showed a top view of the bead area of the top in the 4a . 4c and 4d illustrated separator plate 10 ,

4a shows the along the z-direction 7 stacked separator plates 10 . 11 as well as other separator plates 28 . 29 , The separator plates 10 . 11 . 28 . 29 are identical in each case, with only the configuration of the separator plate being an example here 10 will be described in detail. Emphasized in particular are the beads 15 ' . 15 '' the single plates 10 ' . 10 '' the separator plate 10 and between the beads 15 ' . 15 '' formed beading interior 24 ,

To an undesirable flow of coolant in the bead interior 24 To reduce or prevent, have the beads 15 ' . 15 '' the single plates 10 ' . 10 '' in a section 30 each a lowered area 31 ' . 31 '' on. In the lowered areas 31 ' . 31 '' the beads 15 ' . 15 '' are the perpendicular to the flat planes of the individual plates 10 ' . 10 '' , ie along the z-direction 7 certain minimum heights of the sill roofs 23 ' . 23 '' each continuously smaller than the along the entire course of the beads 15 ' . 15 '' certain middle heights of the beads 15 ' . 15 '' , To illustrate, the middle heights of the beads 15 ' . 15 '' in 4a in the section 30 dashed highlighted. In the lowered areas 31 ' . 31 '' the roofs are enough 23 ' . 23 '' the beads 15 ' . 15 '' transverse to the direction of the beads 15 ' . 15 ' , in 4a ie perpendicular to the plane of the drawing, over the entire width of the beads 15 ' . 15 '' up to the plane planes of the single plates 10 ' . 10 '' or almost up to the plane planes of the single plates 10 ' . 10 '' down. In 4c the flat planes of the individual plates are respectively highlighted by straight lines which are respectively arranged between the bead-roofs of the beads of the same separator plate and along the x-direction 8th run. In particular, the beads are 15 ' . 15 '' designed such that the minimum heights of the beads 15 ' . 15 '' in the lowered areas 31 ' . 31 '' are smaller than the maximum height 22 ' . 22 '' the structures 17 ' . 17 '' in the active areas 16 ' . 16 '' the single plates 10 ' . 10 '' ,

In this way, the cross section of the bead interior 24 through the subsidence of the beads 15 ' . 15 '' reduced so that the flow velocity of the cooling medium in the bead interior 24 between the openings 10c and 10g the separator plate 10 is significantly reduced. This will compensate for the distribution between the flow in the bead interior 24 and those along the between the active areas 16 ' . 16 '' arranged part of the cavity 18 between the openings 10c and 10g the separator plate 10 (please refer 2 ) reached. Thus, due to the subsidence of the beads 15 ' . 15 '' compared to the prior art, a higher proportion of the between the openings 10c and 10g the separator plate 10 flowing cooling medium through the active areas 16 ' . 16 '' directed. For this purpose, z. B. the cross section of the bead interior 24 between the beads 15 ' . 15 '' at the narrowest point along the section 30 ( 4a ) be less than 10 percent of along the entire course of the beads 15 ' . 15 '' certain central cross section of the bead interior 24 ,

In a section 32 Show the beads 15 ' . 15 '' the single plates 10 ' . 10 '' each an elevated area 33 ' . 33 '' on. In the raised areas 33 ' . 33 '' the beads 15 ' . 15 '' are the perpendicular to the flat planes of the individual plates 10 ' . 10 '' , ie along the z-direction 7 certain maximum heights of the sill roofs 23 ' . 23 '' each continuously larger than the along the entire course of the beads 15 ' . 15 '' certain middle heights of the beads 15 ' . 15 '' , To illustrate, the middle heights of the beads 15 ' . 15 '' in 4a also in the section 32 dashed highlighted. Along the sectional plane AA aligned parallel to the xz-plane AA 4b are the raised areas 33 ' . 33 '' the beads 15 ' . 15 '' preferably complementary to the lowered areas 31 ' . 31 '' the beads 15 ' . 15 '' shaped. Because the sill roofs 23 ' . 23 '' the beads 15 ' . 15 '' in the lowered areas 31 ' . 31 '' each lowered to a height of zero, this includes in particular that the maximum height of the beads 15 ' . 15 '' in the raised areas 33 ' . 33 '' preferably in each case twice the mean bead height.

The arrangement of the lowered areas 31 ' , another lowered area 34 ' , the raised area 33 ' and another elevated area 35 ' the bead 15 ' the single plate 10 ' is schematic in the 8th and 9 shown. The lowered areas 31 '' . 34 '' and the raised areas 33 '' . 35 '' the bead 15 '' in the 8th and 9 concealed second single plate 10 '' are located in the same places of the second single plate 10 '' , The arrangements of the beads 15 ' . 15 '' , the lowered areas 31 ' . 31 '' . 34 ' . 34 '' and the raised areas 33 ' . 33 '' . 35 ' . 35 '' are thus arranged symmetrically with respect to a plane of symmetry in the XY direction of the coordinate system, which are parallel to the planar planes of the individual plates 10 ' . 10 '' aligned and between the single plates 10 ' . 10 '' is arranged. This is in the 8th and 9 each by the arrangement of the reference numerals provided with arrows 31 '' . 33 '' . 34 '' . 35 '' indicated.

The beads 15 ' . 15 '' the single plates 10 ' . 10 '' the separator plate 10 thus each have two lowered areas 31 ' . 34 ' respectively. 31 '' . 34 '' and two elevated areas 33 ' . 35 ' respectively. 33 '' . 35 '' on. The arrangement of the lowered areas 31 ' . 31 '' . 34 ' . 34 '' and the raised areas 33 ' . 33 '' . 35 ' . 35 '' along the beads 15 ' . 15 '' is in each case symmetrical with respect to an axis of symmetry 36 , In 8th is the axis of symmetry 36 perpendicular to the planar surface plane of the individual plates 10 ' . 10 '' aligned. In 9 is the axis of symmetry 36 parallel to the planar surface plane of the individual plates 10 ' . 10 '' aligned, in particular parallel to the longer edge of the individual plates 10 ' . 10 '' , The separator plate 10 in the embodiments according to the 8th and 9 So in each case a twofold symmetry with respect to rotations about the axis of symmetry 36 on, so at least the beads 15 ' . 15 '' with their lowered and elevated areas at 180 degrees rotation with respect to the x-axis 8th of the coordinate system can each be brought into coincidence with each other.

Due to this symmetrical configuration of the beads 15 ' . 15 '' can the stack 2 be formed of a plurality of identical separator plates, wherein adjacent separator plates of the stack 2 are each rotated by 180 degrees relative to each other to sealingly engage the facing beads of adjacent Separatorplatten with each other. Are the separator plates of the stack 2 for example according to 8th designed, so every second plate of the stack 2 starting from the orientation according to 8th to rotate 180 degrees about the x-axis, which is arranged relative to the plate like the symmetry axis 36 according to 9 , Are the separator plates of the stack 2 contrary to 9 designed, so every second plate of the stack 2 starting from the orientation according to 9 to rotate 180 degrees about the z-axis, which is arranged relative to the plate like the symmetry axis 36 according to 8th ,

In this way, an arrangement of the stack 2 achieved, as z. In 4a is shown. There grab in the sections 30 . 32 the lowered and the raised portions facing each other adjacent, identical separator plates at least along the longitudinal direction of the beads, in 4a ie along the x-direction 8th , form-fitting into each other. So grab the section 30 the lowered area 31 '' the bead 15 '' the separator plate 10 and an elevated area 36 ' a bead 37 ' the separator plate 11 at least along the direction of the beads 15 '' . 37 ' , in 4a ie along the x-direction 8th , form-fitting into each other. Conversely, in the section 32 the raised area 33 '' the bead 15 '' the separator plate 10 and a lowered area 38 ' the bead 37 ' the separator plate 11 at least along the direction of the beads 15 '' . 37 ' positively in one another. By this at least partially positive engagement of the reductions and increases facing each other adjacent beads, identical separator plates is the stack 2 additionally stabilized.

The lowered areas 31 ' . 34 ' and the raised areas 33 ' . 35 '' the beads 15 ' . 15 '' the separator plate 10 , which is exemplary for all separator plates of the stack 2 can not necessarily be designed to be strictly complementary to each other. Preferably, however, they are at least substantially complementary to each other, so that mutually facing beads of identical, adjacent separator plates of the stack 2 receiving a pressed between the beads edge region of an arranged between the adjacent Separatorplatten MEA, z. B. taking a peripheral area of the MEA 12 (please refer 3 ) between the beads, sealingly engageable with each other. The edge area of the MEA can, for. B. by an outer edge of the polymer membrane 25 may be formed, which is additionally reinforced by the lamination of a reinforcing film (see 3 ). The edge area of the MEA 12 has a perpendicular to the plane surface plane of the membrane composite certain thickness of z. B. 90 microns.

For the sake of clarity, the sections according to the 4a . 4c no MEA between the beads of adjacent separator plates of the stack 2 arranged and pressed. The 4a . 4c However, it can be clearly seen that the sap roofs of Separatorplatten 10 . 11 . 28 . 29 of the pile 2 at least along the course of the beads, in this case along the x-direction 8th , have no edges. Especially in the lowered and elevated areas in the bead sections 30 . 32 the sill roofs have a curved course. This facilitates the pressing of an edge region of an MEA between mutually facing beads of adjacent separator plates. In particular, the at least partially rounded configuration of the beaded roof in the lowered and raised regions of the bead avoids damage to the edge region of a beaded area between the beading plates between the adjacent separator plates.

In 4d are yz cuts through the stack 2 shown, along the in 4b shown sectional planes BB, CC and DD. Along the section plane BB ( 4d , left) corresponds to the height of the bead roofs of the separator plates 10 . 11 . 28 . 29 the average bead height determined along the course of the beads. Likewise corresponds to the separator plates in this section 10 . 11 . 28 . 29 shown bead cross-section of the determined in a straight course of the bead mean bead cross section A _m . Along the cutting plane CC ( 4d , Middle) are the bead roofs of the separator plates 11 . 29 already slightly increased compared to the average bead height, while the bead roofs of the separator plates 10 . 28 opposite to the central bead height complementary to the increased beads of Separatorplatten 11 . 29 are lowered. Along the cutting plane DD ( 4d , right) take the bead roofs of separator plates 11 . 29 their maximum height while the sap compartments of the separator plates 10 . 28 complementary to accept their minimum height.

The average DD in the area 31 ' shown minimum bead cross-section A _min in the separator plates 10 . 28 is opposite to the average bead cross section A _{m of} the separator plates shown in section BB 10 . 11 . 28 . 29 significantly reduced, reducing the flow of cooling medium in the beads of the separator plates 10 . 28 in the area 30 significantly reduced or prevented. On average DD is also in the area 31 ' enlarged bead cross section A _max shown in the Separatorplatten 11 . 29 resulting from the increase in the corresponding beads. For the entire coolant flow in the bead area of the separator plates 11 . 29 However, this enlarged bead cross section has no reinforcing influence, since in the in 4b shown area 33 ' the corresponding beads of Separatorplatten 11 . 29 are again lowered and thus the resulting coolant flow is reduced or prevented even in these beads. Based on 4d is also good to see that the sap roofs of Separatorplatten 10 . 28 in the lowered area ( 4d , Middle and right) each over their entire width, ie along the y-direction 9 , are lowered compared to the average height of the sill roof.

In the section 32 So in the elevated area 33 ' the bead 15 ' , is a transverse to the course of the bead 15 ' , ie along the y-direction 9 certain foot width 39 the bead 15 ' opposite to an average foot width 40 the bead 15 ' increased. In the section 30 , ie in the lowered area 31 ' the bead 15 ' , is the foot width 39 the bead 15 ' opposite the middle foot width 40 the bead 15 ' on the other hand, reduced in size (see 4b ). The mean foot width 40 is z. B. by averaging along the entire course of the bead 15 ' certainly. Here is the along the course of the bead 15 ' certain length of the lowered area 31 ' the bead 15 ' in which the height of the sock roof 23 ' is consistently smaller than the average bead height, about three times the average foot width 40 the bead 15 , It is also along the course of the bead 15 ' certain length of the raised area 33 ' the bead 15 ' in which the height of the sock roof 23 ' is consistently greater than the average bead height, also about three times the average foot width 40 the bead 15 , In modified embodiments, the length of the lowered portion 31 ' and / or the raised area 33 ' the bead 15 ' in each case at least five times the average foot width 40 the bead 15 ' be.

The 5a -D include the representations of 4a -D, where in the 5b and 5d additionally the active areas of the separator plates 10 . 11 . 28 . 29 are shown, which are in the positive y-direction 9 connect to the beads. Exemplary here is only the active area 16 ' on the outside of the single plate 10 ' the separator plate 10 highlighted.

6a shows that already in the 5d (left) illustrated section along the section plane BB according to 5b in an enlarged view. According to shows 6b already in the 5d (right) illustrated section along the cutting plane DD according to 5b in an enlarged view.

The representations of the 7a and 7c correspond to the representations of 6a and 6b , wherein in the active areas between the Separatorplatten 10 . 11 . 28 . 29 additionally membrane composites 12a -C identically constructed membrane-electrode units are shown. Outside edges of polymer membranes 25a -C of the membrane composites 12a C are each between the mutually facing beads of Separatorplatten 10 . 11 . 28 . 29 pressed. In particular the 7c is removable, that the minimum height of the sill roof 23 ' the bead 15 ' the single plate 10 ' in the lowered area 31 ' less than the maximum height 22 ' the structures 17 ' of the active area 16 ' , For example, the minimum height of the sock roof is 23 ' the bead 15 ' in the lowered area 31 ' less than 10 percent of the mean height of the sock roof 23 ' the bead 15 ' ,

The 10a . 10b again show the bead 15 ' the single plate in a plan view. The bead 15 ' runs in each case at least in sections wavelike with a wavelength λ. This at least partially wave-like course of the bead 15 ' is z. B. also in 2 shown. The lowered area extending between the dashed lines 31 ' the bead 15 ' according to 10a extends along the course of the bead 15 ' each over a length of at least 2 · λ. In the embodiment according to 10a goes the change in the height of the sock roof at the same time with a change in the angle of the bead flanks and with a reduction of the transverse to the direction of the bead 15 ' certain amplitude of the wave-like course of the bead 15 ' associated.

The raised area extending between the dashed lines 33 ' the bead 15 ' according to 10b extends along the course of the bead 15 ' each also over a length of at least 2 · λ. In 10b runs the bead 15 ' in the raised area 33 ' straight or essentially straight. The bead flanks are widened arcuately to changes the springback of the bead 15 ' to limit.

Claims (23)

Separator plate ( 10 ) for an electrochemical system ( 1 ) with two individual plates ( 10 ' . 10 '' ) and an arranged between the individual plates cavity ( 18 ) for carrying out a cooling medium, wherein at least one of the individual plates has an active region ( 16 ' . 16 '' ) with structures ( 17 ' . 17 '' ) for guiding a reaction medium on an outer side of the separator plate ( 10 ) as well as a bead ( 15 ' . 15 '' ) for sealing the active area or for sealing an opening (FIG. 10c . 10g ) in the separator plate ( 10 ) is formed, wherein the opening ( 10c . 10g ) for supplying a cooling medium into the cavity ( 18 ) or for discharging a cooling medium from the cavity ( 18 ) is formed, and wherein the bead ( 15 ' . 15 '' ) at least one lowered area ( 31 ' . 31 '' ), in which the height ( 20 ' . 20 '' ) of the beaded roof ( 23 ' . 23 '' ) is smaller than that along the course of the bead ( 15 ' . 15 '' ) certain mean height of the sock roof ( 23 ' . 23 '' ); characterized in that a minimum height of the beaded roof ( 23 ' . 23 '' ) in the lowered area ( 31 ' . 31 '' ) for reducing a coolant flow in the bead interior ( 24 ) less than or equal to a maximum height ( 22 ' . 22 '' ) of the structures ( 17 ' , 17 '') of the active area ( 16 ' . 16 '' ). Separator plate ( 10 ) according to claim 1, characterized in that the bead ( 15 ' . 15 '' ) in the lowered area ( 31 ' . 31 '' ) is lowered over the entire width of the bead. Separator plate ( 10 ) according to claim 1, characterized in that the bead ( 15 ' . 15 '' ) in the lowered area ( 31 ' . 31 '' ) over part of the width of the bead roof ( 23 ' . 23 '' ) is lowered. Separator plate ( 10 ) according to one of the preceding claims, characterized in that the minimum height of the beaded roof ( 23 ' . 23 '' ) in the lowered area is at most 50 percent, preferably at most 25 percent, particularly preferably at most 10 percent of the mean bead height, and / or that the minimum height of the beaded roof ( 23 ' . 23 '' ) in the lowered area at most 90 percent, preferably at most 60 percent, particularly preferably at most 20 percent of the maximum height ( 22 ' . 22 '' ) of the structures ( 17 ' . 17 '' ) of the active area ( 16 ' . 16 '' ) is. Separator plate ( 10 ) according to one of the preceding claims, characterized in that a cross section of the bead interior ( 24 ) in the lowered area ( 31 ' . 31 '' ) is at most 50 percent, preferably at most 25 percent, particularly preferably at most 10 percent of the average bead cross-section. Separator plate ( 10 ) according to one of the preceding claims, characterized in that along the running direction of the bead ( 15 ' . 15 '' ) certain length of the lowered area ( 31 ' . 31 '' ) the bead ( 15 ' . 15 '' ) is at least three times, preferably at least five times a certain transverse to the longitudinal direction of the bead foot width of the bead. Separator plate ( 10 ) according to one of the preceding claims, characterized in that the beaded roof ( 23 ' . 23 '' ) in the lowered area ( 31 ' . 31 '' ) along the main orientation of the bead ( 15 ' . 15 '' ) is curved at least in sections and has no edges. Separator plate ( 10 ) according to one of the preceding claims, characterized in that the bead ( 15 ' . 15 '' ) has at least one elevated area in which the height of the beaded roof ( 23 ' . 23 '' ) is greater than that along the course of the bead ( 15 ' . 15 '' ) certain mean height of the sock roof ( 23 ' . 23 '' ). Separator plate ( 10 ) according to claim 8, characterized in that the maximum height of the beaded roof ( 23 ' . 23 '' ) in the raised area ( 33 ' . 33 '' ) at least 1.3 times, preferably at least 1.5 times, in particular at least 1.7 times times the mean height of the sill roof ( 23 ' . 23 '' ) along the course of the bead ( 15 ' . 15 '' ) is. Separator plate ( 10 ) according to one of claims 8 or 9, characterized in that the beaded roof ( 23 ' . 23 '' ) in the raised area ( 33 ' . 33 '' ) along the main orientation of the bead ( 15 ' . 15 '' ) is curved at least in sections and has no edges. Separator plate ( 10 ) according to one of claims 8 to 10, characterized in that the bead ( 15 ' . 15 '' ) at least two lowered areas ( 31 ' . 31 '' . 34 ' . 34 '' ) and a number of raised areas identical to the number of lowered areas ( 33 ' . 33 '' . 35 ' . 35 '' ) having. Separator plate ( 10 ) according to one of claims 8 to 11, characterized in that the lowered area ( 31 ' . 31 '' . 34 ' . 34 '' ) the bead ( 15 ' . 15 '' ) and the raised area ( 33 ' . 33 '' . 35 ' . 35 '' ) the bead ( 15 ' . 15 '' ) or that the lowered areas of the bead ( 15 ' . 15 '' ) and the raised areas of the bead ( 15 ' . 15 '' ) are arranged and formed such that the bead ( 15 ' . 15 '' ) with a bead of a structurally identical further separator plate ( 11 ) is sealingly engageable, preferably with the inclusion of an edge region of a membrane electrode assembly (MEA) between the beads, in particular in the lowered and elevated portions of the beads. Separator plate ( 10 ) according to one of the preceding claims, characterized in that the bead ( 15 ' . 15 '' ) runs at least in sections like a wave with a wavelength λ, wherein the lowered portion of the bead ( 15 ' . 15 '' ) and / or the raised area of the bead ( 15 ' . 15 '' ) along the direction of the bead ( 15 ' . 15 '' ) extends over a length of at least λ, preferably at least 2 · λ. Separator plate ( 10 ) according to one of the preceding claims, characterized in that the individual plates ( 10 ' . 10 '' ) of the separator plate ( 10 ) are formed of metal, preferably made of stainless steel. Separator plate ( 10 ) according to one of the preceding claims, characterized in that a plane perpendicular to the plane plane of the individual plates ( 10 ' . 10 '' ) particular thickness of the individual plates is between 50 microns and 150 microns, preferably between 70 microns and 110 microns. Separator plate ( 10 ) according to one of the preceding claims, characterized in that the bead ( 15 ' . 15 '' ) and the structures ( 17 ' . 17 '' ) of the active area ( 16 ' . 16 '' ) in the single plate ( 10 ' . 10 '' ) are imprinted. Separator plate ( 10 ) according to one of the preceding claims, characterized in that both individual plates ( 10 ' . 10 '' ) each have an active area ( 16 ' . 16 '' ) with structures ( 17 ' . 17 '' ) for guiding a reaction medium on an outer side of the separator plate ( 10 ) and at least one bead ( 15 ' . 15 '' ) with at least one lowered area ( 31 ' . 31 '' . 34 ' . 34 '' ) and with at least one raised area ( 33 ' . 33 '' . 35 ' . 35 '' ) exhibit. Separator plate ( 10 ) according to claims 12 and 17, characterized in that the beads ( 15 ' . 15 '' ) of the individual plates ( 10 ' . 10 '' ) at least two lowered areas ( 31 ' . 31 '' . 34 ' . 34 '' ) and two elevated areas ( 33 ' . 33 '' . 35 ' . 35 '' ), wherein the lowered areas ( 31 ' . 31 '' . 34 ' . 34 '' ) and the raised areas ( 33 ' . 33 '' . 35 ' . 35 '' ) with respect to an axis of symmetry ( 36 ) are arranged symmetrically. Separator plate ( 10 ) according to claim 18, characterized in that the axis of symmetry ( 36 ) perpendicular or parallel to the plane planes of the individual plates ( 10 ' . 10 '' ) is aligned. Separator plate ( 10 ) according to claim 19, characterized by a twofold rotational symmetry with respect to the axis of symmetry ( 36 ). Electrochemical system ( 1 ), in particular fuel cell system, electrochemical compressor, humidifier for a fuel cell system or electrolyzer, with a layering of cells each having at least one membrane composite ( 12 ) each having at least one polymer membrane ( 25 ), each cell being separated by separator plates ( 10 . 11 . 28 . 29 ) are separated according to one of claims 8 to 20, wherein directly adjacent Separatorplatten ( 10 . 11 ) facing each other beads ( 15 '' . 37 ' ) each having at least one lowered area ( 31 ' . 38 ' ) and each having at least one elevated area ( 33 ' . 36 ' ) and wherein the lowered areas ( 31 ' . 38 ' ) and the raised areas ( 33 ' . 36 ' ) in the mutually facing beads ( 15 '' . 37 ' ) are arranged and formed so complementary to one another that the mutually facing beads ( 15 '' . 37 ' ) are sealingly engaged with each other, preferably by receiving at least one edge region of a membrane electrode assembly (MEA) between the mutually facing beads. Electrochemical system according to Claim 21, having a membrane composite which is located between two directly adjacent separator plates ( 10 . 11 ), wherein the mutually facing beads ( 15 '' . 37 ' ) in the raised areas ( 33 ' . 36 ' ) with respect to along the course of the respective bead ( 15 '' . 37 ' ) are increased by at least a certain amount, the average height of the sill roof, the a thickness of the membrane composite ( 12 ) in the compressed state corresponds. Electrochemical system according to one of claims 21 or 22 having a multiplicity of identically constructed separator plates ( 10 . 11 . 28 . 29 ).

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