Method for cohesive connection of first bipolar plate layer and second bipolar plate layer, bipolar plate for electrochemical cell of electrochemical device, and electrochemical device

Abstract

In order to provide a method for the cohesive connection of a first bipolar plate layer and a second bipolar plate layer of a bipolar plate for an electrochemical cell of an electrochemical device, the electrochemical device comprises a plurality of electrochemical cells following one behind the other in the stacking direction, the method comprises the following:-placing a first bipolar plate layer and a second bipolar plate layer in contact at one or more contact regions of the bipolar plate layers; applying a clamping force to the first bipolar plate layer and the second bipolar plate layer by means of one or more clamping tools; and-connecting the first bipolar plate layer and the second bipolar plate layer together in a cohesive manner along the connecting seam; the invention relates to a method for connecting two bipolar plate layers to each other in a process-reliable manner without deteriorating the flow characteristics of the bipolar plate or without impeding the support function of the bipolar plate for a component of an electrochemical cell of an electrochemical device, which method makes it possible to connect two bipolar plate layers to each other in a process-reliable manner. At least one clamping tool is supported on a support surface of at least one support structure of at least one of the bipolar plate layers, the support surface of the support structure being offset in the stacking direction in relation to a surface of the bipolar plate layer on which the support structure is formed in the contact region in such a way as to leave the respective other bipolar plate layer.

Description

Technical Field

[0001] The invention relates to a method for materially connecting a first bipolar plate layer and a second bipolar plate layer of a bipolar plate for an electrochemical cell of an electrochemical device, the electrochemical device comprising a plurality of electrochemical cells following one another in a stacking direction, wherein the method comprises the following items: - placing the first bipolar plate layer and the second bipolar plate layer in contact at one or more contact regions of the bipolar plate layers; - applying a clamping force to the first bipolar plate layer and the second bipolar plate layer by means of one or more clamping tools; and - Connecting the first bipolar plate layer and the second bipolar plate layer in a material-locking manner along the connecting seam. Background Art

[0002] The connecting seam is preferably produced here by welding, in particular by laser welding.

[0003] In order to produce such a connection seam, a specially assigned and high-precision welding tool is required, which includes a clamping tool for applying a clamping force to the first bipolar plate layer and the second bipolar plate layer, so that the first bipolar plate layer and the second bipolar plate layer are only separated from each other by an almost "technical zero gap" in the contact area where the bipolar plate layers are to be connected to each other, and the "technical zero gap" has a height (along the stacking direction of the electrochemical device) of less than 0.03 mm. For this purpose, a clamping tool, which is configured as a clamping strip, for example, must be placed on both sides of the connection seam to be produced on the flat area of ​​the bipolar plate layer in order to achieve a sufficient clamping effect.

[0004] The connecting seams of the bipolar plate layers and the surface areas to be retained on both sides of the connecting seams require a considerable proportion of the available space of the entire bipolar plate, which is disadvantageous in terms of development and design technology because a large amount of space is also required to arrange elements introduced into the bipolar plate layers by deformation, which are used to redirect the medium (anode gas, cathode gas, coolant) to be supplied to the electrochemical device and / or support components of the electrochemical cell adjacent to the bipolar plate, such as components of the gas diffusion layer or sealing assembly of the electrochemical cell.

[0005] If the surface area of ​​the bipolar plate layers to be connected to one another that must remain for the arrangement of the clamping tools is too large, this will have a negative impact on the fluid-mechanical properties of the bipolar plate. Summary of the invention

[0006] The object of the present invention is to provide a method for materially connecting a first bipolar plate layer and a second bipolar plate layer of a bipolar plate for an electrochemical cell of an electrochemical device of the type described at the outset, which method makes it possible to connect the two bipolar plate layers to each other in a process-reliable manner without deteriorating the flow characteristics of the bipolar plate or impairing the supporting function of the bipolar plate for the components of the electrochemical cell of the electrochemical device.

[0007] According to the invention, this object is achieved in a method for materially connecting a first bipolar plate layer and a second bipolar plate layer of a bipolar plate of an electrochemical cell for an electrochemical device having the features of the preamble of claim 1 in that at least one clamping tool is supported on a supporting surface of at least one supporting structure of at least one of the bipolar plate layers, wherein the supporting surface of the supporting structure is offset in the stacking direction away from the respective other bipolar plate layer relative to the surface of the bipolar plate layer on which the supporting structure is constructed in the contact region.

[0008] The solution according to the invention is based on the idea that the structure which is preferably formed into at least one bipolar plate layer and which is required anyway for redirecting the medium flow and / or for supporting components of the electrochemical cell is additionally used to support at least one clamping tool during the production of the connecting seam between the first bipolar plate layer and the second bipolar plate layer of the bipolar plate.

[0009] At least one supporting structure is designed to have a supporting surface for supporting a clamping tool during the production of the connecting seam, wherein the supporting surface can preferably also be used to support components of the electrochemical cell adjacent to the supporting structure, such as a gas diffusion layer of the electrochemical cell or a component of a sealing assembly.

[0010] The height of the support structure, i.e. the distance between the support surface and the surface of the bipolar plate layer on which the support structure is constructed in the contact area (in which the bipolar plate layer preferably lies flat against the corresponding other bipolar plate layer), is coordinated with the adjacent components of the electrochemical cell to be supported (e.g. membrane electrode assembly).

[0011] The shape of the supporting structure, especially the outer contour, is optimized for the process of producing the connecting seam.

[0012] As a result, space can be saved on the bipolar plate that would otherwise have to be reserved for arranging a clamping tool during the production of the connecting seam.

[0013] The at least one supporting structure can be, for example, bowl-shaped or “dimple-shaped” with a round, oval or free-form edge.

[0014] The edge of the supporting structure is here a line at which the supporting structure transitions into a flat region oriented parallel to the stacking direction.

[0015] Such a support structure may be arranged on the bipolar plate layer on the anode side, or may be arranged on the bipolar plate layer on the cathode side.

[0016] Preferably, such a supporting structure is formed by a shaping process on one of the bipolar plate layers, for example by an embossing process or a deep-drawing process.

[0017] The maximum extension of such a support structure perpendicular to the stacking direction is preferably about 3 mm to about 7 mm, for example about 5 mm.

[0018] Such a supporting structure can be formed on one side on the anode-side bipolar plate layer or on the cathode-side bipolar plate layer, wherein the respective other bipolar plate layer then has planar free surfaces in corresponding regions, against which the clamping tool can rest during the production of the connecting seam.

[0019] Alternatively, it can also be provided that a preferably cup-shaped support structure is also formed on the respective other bipolar plate layer, which (as viewed in the stacking direction of the electrochemical device) is substantially congruent with the support structure on the first bipolar plate layer, or is only slightly offset relative to the support structure on the first bipolar plate layer. Due to the deformation of the support structures arranged in the same position on the two bipolar plate layers to be connected to each other, a force balance is achieved when these support structures are pressed by means of a clamping tool placed in contact with the support structure, according to which the force generated from the bipolar plate layers to each other and the force generated from the bipolar plate layers to the clamping tool are equal to each other ("action force equals reaction force").

[0020] As an alternative or in addition thereto, it can also be provided that at least one rib structure on at least one of the bipolar plate layers to be connected is designed in the form of a rib and extends substantially parallel to the connecting seam.

[0021] The support surface formed on such a rib-like support structure preferably has an extension perpendicular to the stacking direction of less than 3 mm, particularly preferably less than 1.5 mm.

[0022] Such a rib-like supporting structure can be arranged on one side only on the bipolar plate layer on the anode side or only on the bipolar plate layer on the cathode side, wherein the respective other bipolar plate layer has a flat free surface in this area, against which the clamping tool can rest during the production of the connecting seam.

[0023] Alternatively, it can also be provided that a rib-shaped second support structure is also provided on the corresponding other bipolar plate layer, and the rib-shaped second support structure is symmetrically configured (with respect to the contact surface of the two bipolar plate layers) with the rib-shaped first support structure, or only slightly deviates from the shape of the rib-shaped first support structure. Preferably, the positioning of the rib-shaped second support structure (seen in the stacking direction) is substantially congruent with the positioning of the rib-shaped first support structure, or is only slightly offset relative to the positioning of the rib-shaped first support structure.

[0024] The edges of the flat region of the support structure, which transitions from the support structure to the respective bipolar plate layer, preferably meet again on two mutually opposite sides of the rib-shaped support structure, so that the two bipolar plate layers are "blocked" against each other. As a result, when the rib-shaped support structure is compressed by means of a clamping tool, the forces from the bipolar plate layers on each other and the forces exerted by the bipolar plate layers on the clamping tool during the production of the connecting seam are equal in magnitude ("action force equals reaction force").

[0025] In a further embodiment of the invention, it is provided that one of the bipolar plate layers to be connected to one another has a plurality of rib-like supporting structures which extend transversely to the connecting seam and end at a small distance from the connecting seam.

[0026] In this case, in the region of these tapering rib-like supporting structures, the respective other bipolar plate layer has a planar free surface, against which the clamping tool can rest during the production of the connecting seam.

[0027] Alternatively, it can also be provided that in the region where a first bipolar plate layer has rib-like supporting structures transverse to the connecting seam, the respective other bipolar plate layer has one or more rib-like supporting structures extending substantially parallel to the connecting seam.

[0028] The edges of these supporting structures meet in the region between the rib-like supporting structures of the first bipolar plate layer extending transversely to the connecting seam and on the side of the rib-like supporting structures of the second bipolar plate layer facing away from the connecting seam, so that the two bipolar plate layers are "blocked" against each other at these locations. As a result, a force balance is achieved during the production of the connecting seam when the supporting structures are pressed, in which the forces from the bipolar plate layers on each other and the forces exerted by the bipolar plate layers on the clamping tool are equal in magnitude ("action force equals reaction force").

[0029] The edge of the flat region of the support structure, in which the support structure transitions into the bipolar plate layer, is preferably located at a distance of less than 1 mm, in particular less than 0.5 mm, particularly preferably less than 0.1 mm from the connecting seam.

[0030] On the side of the support structure facing away from the connecting seam, the edge of the support structure formed on one of the bipolar plate layers preferably merges with the edge of the other support structure formed on the respective other bipolar plate layer, so that the bipolar plate layers are "blocked" against each other in this section of their edges, so that a sufficient supporting effect is achieved through the resulting force balance ("action force equals reaction force").

[0031] The section of the support structure facing away from the connecting joint is preferably located at a distance of more than 1 mm and / or less than 5 mm from the connecting joint.

[0032] The at least one supporting structure of the bipolar plate produced according to the invention allows, on the one hand, the clamping tool to be arranged very close to the connecting seam during the production of the connecting seam. On the other hand, the at least one supporting structure can be used to support adjacent components of the electrochemical device, such as a gas diffusion layer of the electrochemical cell or a structural element of the sealing assembly.

[0033] At least one supporting structure is designed as a stabilizing element which serves to absorb the clamping forces of the clamping tool during the production of the connecting seam and is arranged as close as possible to the connecting seam.

[0034] At least one supporting structure formed on one of the bipolar plate layers is preferably supported both on its side facing the connecting seam and on its side facing away from the connecting seam on a supporting structure formed on the respective other bipolar plate layer.

[0035] By applying a clamping force to the support structure of the bipolar plate with the aid of a clamping tool, it is achieved that the bipolar plate layers to be connected to each other are spaced apart from each other only by a very small gap in the contact area (in which the bipolar plate layers preferably lie against each other in a planar manner and are to be connected to each other via a connecting seam), the gap having a height (in the stacking direction) of less than 0.03 mm.

[0036] During operation of the electrochemical device, the supporting effect of the support structure ensures that components of the electrochemical cell supported on the support structure, such as the gas diffusion layer, subgasket or other elements of the sealing assembly of the electrochemical cell, do not penetrate into the intermediate space between the medium distribution area and the medium through-opening of the bipolar plate, thereby closing the medium outlet or medium distribution area of ​​the sealed rib.

[0037] In a preferred embodiment of the invention, it is provided that at least one clamping tool is supported on a plurality of support surfaces of a plurality of different support structures and on a plurality of contact regions of the bipolar plate layers between the support structures.

[0038] It is preferably provided that at least one first clamping tool is supported on at least one first supporting structure formed on a first bipolar plate layer, and at least one second clamping tool is supported on at least one second supporting structure formed on a second bipolar plate layer.

[0039] The first support structure has a first edge where it transitions into the planar region of the first bipolar plate layer, and the second support structure has a second edge where it transitions into the planar region of the second bipolar plate layer.

[0040] In this case, the first edge and the second edge preferably substantially coincide with each other in a projection onto a plane oriented perpendicular to the stacking direction, or preferably deviate from each other by a distance of at most 0.5 mm. The distance is preferably measured perpendicularly to the longitudinal direction of the first edge or perpendicularly to the longitudinal direction of the second edge.

[0041] In a special embodiment of the invention, it is provided that at least one supporting structure is formed at a location of one of the bipolar plate layers which is opposite a planar region of the respective other bipolar plate layer which is not provided with a supporting structure.

[0042] The supporting surface of the at least one supporting structure preferably has a minimum extension (a) perpendicular to the stacking direction of at least 0.1 mm, in particular at least 0.5 mm.

[0043] Furthermore, the supporting surface of the at least one supporting structure preferably has a minimum extension (a) perpendicular to the stacking direction of at most 3 mm, in particular at most 1.5 mm.

[0044] As an alternative or in addition thereto, it can be provided that the support surface of at least one support structure has a maximum extension perpendicular to the stacking direction of more than 3 mm, in particular more than 5 mm.

[0045] In a preferred embodiment of the present invention, it is provided that at least one support structure has an edge at which the support structure transitions into a flat region on which the bipolar plate layers of the support structure are constructed, wherein the minimum distance (d) between the edge of the support structure and the center line of the connecting seam is at most 0.8 mm, in particular at most 0.5 mm, particularly preferably at most 0.3 mm.

[0046] In this case, the minimum distance (d) between the edge of the supporting structure and the center line of the connecting joint is preferably perpendicular to the center line of the connecting joint.

[0047] It is furthermore preferably provided that at least one support structure has an edge at which the support structure transitions into a planar region on which the bipolar plate layers of the support structure are formed, wherein the maximum distance (D) between the edge of the support structure and the center line of the connecting seam is at most 5 mm, in particular at most 3 mm, particularly preferably at most 2 mm.

[0048] The maximum distance (D) between the edges of the supporting structure is preferably taken perpendicularly to the center line of the connecting seam.

[0049] At least one support structure may be configured in the form of a bowl.

[0050] Furthermore, it can be provided that at least one supporting structure is designed to be circular or elliptical in a plan view in the stacking direction.

[0051] As an alternative or in addition thereto, it may be provided that at least one supporting structure is designed in the form of a rib.

[0052] The rib-like supporting structure can extend at least in sections substantially parallel to the connecting seam.

[0053] Alternatively or additionally thereto, it may be provided that a plurality of rib-like supporting structures extend transversely to the connecting seam and end at a distance (d′) of less than 0.8 mm, in particular less than 0.5 mm, particularly preferably less than 0.3 mm from the center line of the connecting seam.

[0054] The distance (d′) from the center line of the connecting seam is preferably taken perpendicularly to the center line of the connecting seam.

[0055] The invention also relates to a bipolar plate for an electrochemical cell of an electrochemical device, the electrochemical device comprising a plurality of electrochemical cells following one another in a stacking direction, Among them, the bipolar plate includes: A first bipolar plate layer and a second bipolar plate layer are materially connected to one another along a connecting seam in the contact region of the bipolar plate layers.

[0056] A further object of the present invention is to provide a bipolar plate of the type mentioned at the outset in which the first bipolar plate layer and the second bipolar plate layer can be connected to one another in a process-reliable manner without the flow characteristics of the bipolar plate being impaired or without impairing the supporting function of components of the electrochemical cell adjacent to the bipolar plate.

[0057] This object is achieved according to the bipolar plate of claim 15 , wherein at least one supporting structure is respectively formed on the first bipolar plate layer and / or the second bipolar plate layer. wherein the support surface of at least one support structure is offset in the stacking direction relative to the surface of the bipolar plate layer on which the support structure is constructed in the contact region in a manner away from the respective other bipolar plate layer, and Therein, at least one support structure has an edge at which the support structure transitions into a flat region on which the bipolar plate layers of the support structure are formed, wherein a minimum distance (d, d′) between the edge of the support structure and a center line of the connecting seam is at most 0.8 mm, in particular at most 0.5 mm, particularly preferably at most 0.3 mm.

[0058] In this case, the minimum distance (d, d′) between the edge of the supporting structure and the center line of the connecting joint is preferably perpendicular to the center line of the connecting joint.

[0059] The particular embodiment of the bipolar plate has already been explained above in conjunction with the method according to the invention for materially bonding a first bipolar plate layer and a second bipolar plate layer of a bipolar plate for an electrochemical cell of an electrochemical device.

[0060] The method according to the invention for integrally connecting a first bipolar plate layer and a second bipolar plate layer of a bipolar plate can be used in particular for integrally connecting bipolar plate layers of a bipolar plate according to the invention.

[0061] The bipolar plate according to the invention can be produced in particular by using the method according to the invention for integrally connecting a first bipolar plate layer and a second bipolar plate layer of a bipolar plate.

[0062] The bipolar plate according to the invention is particularly suitable for use in an electrochemical device comprising a plurality of electrochemical cells which follow one another in the stacking direction and each comprise a bipolar plate according to the invention.

[0063] Such an electrochemical device may be, for example, a fuel cell device or an electrolysis apparatus.

[0064] For example, the electrochemical device may be configured as a polymer electrolyte membrane (PEM) fuel cell device. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Further features and advantages of the invention are the subject matter of the following description of embodiments and of the drawings.

[0066] in:

[0067] Figure 1 A plan view of a bipolar plate for an electrochemical cell of an electrochemical device is shown, viewing in the direction of the anode side of the bipolar plate, the electrochemical device comprising a plurality of electrochemical cells following one another in a stacking direction, The bipolar plate comprises a first bipolar plate layer and a second bipolar plate layer which are materially connected to one another along a connecting seam in a contact region of the bipolar plate layers, Wherein, at least one supporting structure is respectively constructed on the first bipolar plate layer and / or the second bipolar plate layer, wherein the support surface of at least one support structure is offset in the stacking direction relative to the surface of the bipolar plate layer on which the support structure is constructed in the contact region in a manner away from the respective other bipolar plate layer, and wherein at least one of the support structures has an edge at which the support structure transitions into a planar region on which the bipolar plate layers of the support structure are formed, The minimum distance between the edge of the supporting structure and the center line of the joint perpendicular to the center line of the joint is at most 0.8 mm;

[0068] Figure 2 Shows Figure 1 A top view of the left end region of the bipolar plate;

[0069] Figure 3 Shows Figure 2 An enlarged view of region I;

[0070] Figure 4 along Figure 3 The line 4-4 in FIG. 4 shows Figure 3 A fragmentary, partially cutaway illustration of a region of a bipolar plate;

[0071] Figure 5 Shows Figure 3 A top view of a connection seam of a bipolar plate and a section of a support structure adjacent to the connection seam;

[0072] Figure 6 The cathode side of the bipolar plate is shown in the viewing direction. Figure 2 A top view of an end region of a bipolar plate;

[0073] Figure 7 Shows Figure 6 An enlarged view of region II;

[0074] Figure 8 along Figure 7 Line 8-8 in FIG. 8 shows a longitudinal section of a section of a support structure of a bipolar plate configured as a rib;

[0075] Fig. 9 Shows Figure 6 An enlarged view of region III;

[0076] Fig.10 A schematic cross-sectional view is shown, which illustrates how a clamping force is applied to a first bipolar plate layer and a second bipolar plate layer by means of a plurality of clamping tools, wherein the clamping tools are supported on both sides of the connecting seam to be produced on a corresponding supporting structure of the first bipolar plate layer and on a corresponding supporting structure of the second bipolar plate layer;

[0077] Fig.11 along Fig.10 Line 11-11 shows a schematic longitudinal section through a clamping tool, which is supported on a bowl-shaped support structure formed on the first bipolar plate layer and the second bipolar plate layer, and on a flat region of the first bipolar plate layer and the second bipolar plate layer between the support structures;

[0078] Fig.12 Shown with Fig.10 A corresponding schematic cross-sectional view through a bipolar plate layer and a clamping tool supported on a support structure of the bipolar plate layer, wherein Fig.12 Such a support structure is constructed only on the first bipolar plate layer on the left side of the connection seam in;

[0079] Fig.13 along Fig.12 Line 13-13 in the figure shows the Fig.11 a corresponding schematic longitudinal section through the clamping tool and the support structure formed on the first bipolar plate layer;

[0080] Fig.14 A plan view of a section of a medium distribution region of a second embodiment of a bipolar plate is shown, wherein a rib-like support structure of the medium flow field extends obliquely relative to a section of a connecting seam of the bipolar plate;

[0081] Fig.15 Shows Fig.14 A top view of the back side of a bipolar plate region of the embodiment of the present invention, wherein the rib-like support structure of the medium flow field extends parallel to a section of the connecting seam of the bipolar plate; and

[0082] Fig.16 along Fig.14 Line 16-16 shows Fig.15 and Fig.16 A longitudinal section of a bipolar plate, wherein Fig.15 The course of the section plane in is indicated by the line 16 ′- 16 ′.

[0083] In all figures, identical or functionally equivalent elements are marked with the same reference numerals. DETAILED DESCRIPTION

[0084] Figures 1 to 9 The bipolar plate shown in the figure, which is designated as a whole by 100, forms a component of an electrochemical cell 102 (not shown as a whole). In addition to the bipolar plate 100, the electrochemical cell may also include a membrane electrode assembly, a gas diffusion layer and a sealing assembly.

[0085] A plurality of such electrochemical cells 102 follow one another in a stacking direction 104 in order to form a stack of electrochemical cells 102 , which is a component of an electrochemical device 106 , for example a fuel cell device.

[0086] The bipolar plate 100 has a substantially rectangular shape, wherein long sides 107 of the bipolar plate 100 extend along a longitudinal direction 108 and short sides 109 of the bipolar plate 100 extend along a transverse direction 110 of the bipolar plate 100 .

[0087] The longitudinal direction 108 and the transverse direction 110 are preferably oriented perpendicularly to one another and perpendicularly to the stacking direction 104 .

[0088] The longitudinal direction 108 is also referred to as the x-direction, the transverse direction 110 is referred to as the y-direction, and the stacking direction 104 is referred to as the z-direction.

[0089] The x-direction, y-direction and z-direction develop a rectangular coordinate system.

[0090] The bipolar plate 100 has two end regions 112 and an electrochemically active region 114 located between the end regions 112 .

[0091] The electrochemically active region 114 of the bipolar plate 100 includes an anode gas flow field 116 through which an anode gas can flow, a cathode gas flow field 118 through which a cathode gas can flow, and a coolant flow field 120 through which a coolant can flow.

[0092] In the embodiment described herein, the bipolar plate 100 is constructed in two layers and includes a first bipolar plate layer 121 and a second bipolar plate layer 123 .

[0093] In the illustrated embodiment, the first bipolar plate layer 121 is an anode-side bipolar plate layer 122 on which an anode gas flow field 116 is constructed, and the second bipolar plate layer 123 is a cathode-side bipolar plate layer 124 on which a cathode gas flow field 118 is constructed.

[0094] However, in principle, the first bipolar plate layer 121 may also be the bipolar plate layer 124 on the cathode side, and the second bipolar plate layer 123 may be the bipolar plate layer 122 on the anode side.

[0095] The bipolar plate layers 121 and 123 are made of a material that is good at conducting electricity, preferably a metal material.

[0096] The bipolar plate layers 121 and 123 are connected to one another in a materially bonded manner along the connecting seam 294 , preferably welded, in particular by laser welding.

[0097] The anode flow field 116 of the bipolar plate 100 is in fluid connection with the anode-side electrode of the membrane electrode assembly (optionally via an anode-side gas diffusion layer).

[0098] The cathode flow field 118 of the bipolar plate 100 is in fluid connection with the cathode-side electrode of the membrane electrode assembly (optionally via a cathode-side gas diffusion layer).

[0099] Therefore, the anode gas and the cathode gas can reach the electrochemically active regions of the respective membrane electrode assemblies from the electrochemically active region 114 of the bipolar plate 100. Therefore, the region of the bipolar plate 100 where the anode gas flow field 116 and the cathode gas flow field 118 are provided is referred to as the electrochemically active region 114 of the bipolar plate, even though the bipolar plate 100 itself does not undergo an electrochemical reaction.

[0100] The anode gas flow field 116 includes anode gas flow channels 126 , the primary flow directions of which are oriented parallel to the longitudinal direction 108 (x-direction) of the bipolar plate 100 .

[0101] The cathode gas flow field 118 includes cathode gas flow channels 128 , the primary flow directions of which are oriented parallel to the longitudinal direction 108 (x-direction) of the bipolar plate 100 .

[0102] In the end region 112 of the bipolar plate ( Figures 2 to 9 1 , the first end region 112 a of which is shown in FIG. 1 ), the bipolar plates 100 each have a plurality of medium passage openings 130, through which a fluid medium (anode gas (fuel gas, such as hydrogen), cathode gas (oxidant, such as oxygen or air) or coolant (such as water)) to be supplied to the electrochemical device 106 can pass through the bipolar plates 100. The medium passage openings 130 of the bipolar plates 100 that follow one another in a stack of electrochemical cells 102 and the intermediate spaces between the medium passage openings 130 in the stacking direction 104 jointly form medium channels 132, respectively.

[0103] Each of the media channels 132 in one of the end regions 112 of the bipolar plate 100 , through which a fluid medium can be supplied to the electrochemical device 100 , is assigned a further media channel 132 in the respective opposite end region 112 , through which the relevant fluid medium can be discharged from the electrochemical device 106 .

[0104] In this case, the fluid medium passes from one end region 112 to the other end region 112 via an anode gas flow field 116 , a cathode gas flow field 118 or a coolant flow field 120 in the electrochemically active region 114 of the bipolar plate 100 .

[0105] exist Figures 2 to 9 An anode gas through-opening 134 , a cathode gas through-opening 136 and a coolant through-opening 138 are arranged in the first end region 112 a of the bipolar plate 100 shown in FIG.

[0106] In this case, each of these through-openings 134 , 136 and 138 can in principle be used selectively to supply the relevant medium to the electrochemical device 106 or to discharge the relevant medium from the electrochemical device 106 .

[0107] In principle, each of the three media, anode gas, cathode gas and coolant, can flow through the electrochemically active region 114 parallel to the respective other media or in a main flow direction opposite to the main flow direction of one or two of the other media.

[0108] In a preferred design scheme of the present invention, it is provided that all through-openings 134, 136 and 138 arranged in the first end region 112a of the bipolar plate 100 are used to supply respective media to the electrochemical device 106, while the through-openings 134, 136 and 138 arranged in the second end region 112b of the bipolar plate 100 are used to discharge respective media from the electrochemical device 106.

[0109] In order to prevent the fluid medium from unintentionally escaping from the respectively associated through-openings 134 , 136 and 138 , each of these through-openings is provided with a respective sealing rib 140 .

[0110] The anode gas through-opening 134 is surrounded by an anode gas sealing rib 142 .

[0111] In order to transport the anode gas from the anode gas through-opening 134 to the anode gas flow field 136, the anode gas sealing rib 142 is provided with a plurality of anode gas inlets 144 on its inner side facing the anode gas through-opening 134, through which the anode gas can flow from the anode gas through-opening 134 into the inner space of the anode gas sealing rib 142 (see Figure 2 ).

[0112] The anode gas inlet 144 opens in each case at an edge 146 of the anode gas passage opening 134 .

[0113] In the illustrated embodiment, the edge 146 of the anode gas through-opening 134 is configured as a quadrilateral; however, the polygonal edge 146 of the anode gas through-opening 134 may also have more or less than four corners.

[0114] The corners of the anode gas through-openings 134 are preferably rounded in order to avoid tearing of the bipolar plate layers 122 and 124 in the region of these corners.

[0115] In order to enable the anode gas to escape from the inner space of the anode gas sealing rib 142 , the anode gas sealing rib 142 is provided with a plurality of anode gas outlets 154 on its outer side facing away from the anode gas through-opening 134 .

[0116] The anode gas outlet 154 is preferably arranged on a section 156 of the anode gas containment rib 142 that faces the electrochemically active region 114 of the bipolar plate 100 .

[0117] The anode gas inlets 144 arranged on the same section 156 of the anode gas sealing rib 142 are preferably offset relative to the anode gas outlets 154 along the circumferential direction of the anode gas sealing rib 142 .

[0118] The anode gas flows out through the anode gas outlet 154 on the section 156 of the anode gas sealing rib 142 into the anode gas distribution region 170 , which is used to distribute the anode gas to the anode gas flow channels 126 of the anode gas flow field 116 as evenly as possible.

[0119] The anode gas distribution region 170 includes a plurality of directional distribution structures 172 and a plurality of non-directional distribution structures 174, which are used to redirect the anode gas away from its original flow direction.

[0120] In this case, the directional distributing structure 172 is designed, for example, as a distributing rib 176 extending essentially linearly.

[0121] The non-directional distributing structure 174 is designed, for example, as a substantially bowl-shaped distributing projection 178 .

[0122] The distributor structures 172 and 174 and all other structures of the bipolar plate 100 described above and below are preferably formed integrally with the material of the bipolar plate layer 121 or 123 and introduced into the respective bipolar plate layer 121 or 123 by a shaping process, for example by an embossing process or a deep drawing process.

[0123] The cathode gas through-opening 136 is surrounded by a cathode gas sealing rib 162 .

[0124] The coolant passage opening 138 is surrounded by a coolant-tightening rib 164 .

[0125] An annularly closed edge rib 182 surrounds the outer edge 180 of the bipolar plate 100 .

[0126] The edge ribs 182 surround the electrochemically active area 114 of the bipolar plate 100 , the anode gas through-openings 134 and the anode gas sealing ribs 142 in the two end areas 112 of the bipolar plate 100 , the cathode gas through-openings 136 and the cathode gas sealing ribs 162 in the two end areas 112 , and the coolant through-openings 138 and the coolant sealing ribs 164 in the two end areas 112 .

[0127] The edge beads 182 are used to prevent the medium to be supplied to the electrochemical device 106 , in particular anode gas, cathode gas and coolant, from escaping from the electrochemical cell 102 into an exterior space 184 of the electrochemical device 106 .

[0128] In order to allow the cathode gas to flow out from the cathode gas through-opening 136 through the cathode gas sealing rib 162, the cathode gas sealing rib 162 is provided with a plurality of cathode gas inlets 194 on its inner side facing the cathode gas through-opening 136 (see in particular Figure 6 ).

[0129] The cathode gas enters the inner space of the cathode gas sealing rib 162 from the cathode gas through-opening 136 through the cathode gas inlet 194 .

[0130] The cathode gas inlet 194 preferably opens out at an edge 198 of the cathode gas through-opening 136 .

[0131] In the illustrated embodiment, the edge 198 of the cathode gas through opening 136 is configured as a quadrilateral. However, the number of corners of the polygonal edge 198 may be less than or more than four.

[0132] The cathode gas outlets 214 arranged on the outer side of the cathode gas sealing rib 162 facing away from the cathode gas through-opening 136 and enabling the cathode gas to flow out from the inner space of the cathode gas sealing rib 162 are preferably all arranged on the section 200 of the cathode gas sealing rib 162 facing the electrochemically active area 114 of the bipolar plate 100.

[0133] Preferably, the cathode gas inlets 194 arranged on the same section 200 of the cathode gas sealing rib 162 are arranged offset relative to the cathode gas outlets 214 in the circumferential direction of the cathode gas sealing rib 162 .

[0134] Preferably, a total of two or more, in particular four or more, in particular six or more, and in the present embodiment, eight cathode gas outlets 214 are provided on the cathode gas sealing rib 162 .

[0135] The cathode gas flows out through the cathode gas outlet 214 into the cathode gas distribution region 216 of the bipolar plate 100 . The cathode gas distribution region is used to distribute the cathode gas into the cathode gas flow channels 128 of the cathode gas flow field 118 as evenly as possible.

[0136] For this purpose, the cathode gas distribution region comprises distribution structures 218 which are designed as directional distribution structures 220 or as non-directional distribution structures 221 .

[0137] The directional distributing structure 220 is preferably designed as a linearly extending distributing rib 222 .

[0138] The non-directional distributing structure 221 is designed, for example, as a substantially bowl-shaped distributing projection 223 .

[0139] In order to allow the coolant to flow out of the coolant through-opening 138 and into the coolant flow field 120 of the bipolar plate 100, the coolant sealing rib 164 is provided with a plurality of coolant inlets 224 on its inner side facing the coolant through-opening 138 (see in particular Figure 2 and Figure 6 ).

[0140] The coolant enters the inner space of the coolant sealing rib 164 from the coolant through-opening 138 through the coolant inlet 224 .

[0141] In the illustrated embodiment, the edge 228 of the coolant through-opening 138 is configured as a quadrilateral. However, the number of corners of the polygonal edge 228 of the coolant through-opening 138 may also be more or less than four.

[0142] Coolant outlets 225 arranged on the outer side of the coolant sealing rib 164 facing away from the coolant passage opening 138 and through which coolant can flow out of the interior space of the coolant sealing rib 164 are preferably all arranged on a section 230 of the coolant sealing rib 164 facing the electrochemically active region 114 of the bipolar plate 114 .

[0143] Preferably, the coolant inlet 224 arranged on the same section 230 of the coolant-tightening rib 164 is arranged offset relative to the coolant outlet 225 in the circumferential direction of the coolant-tightening rib 164 .

[0144] The coolant flows out through the coolant outlet 225 into the coolant distribution region 242 of the bipolar plate 100 , which is used to distribute the coolant as evenly as possible into the coolant channels of the coolant flow field.

[0145] In the coolant distribution area 242, the bipolar plate layer 122 on the anode side and the bipolar plate layer 124 on the cathode side are offset in opposite directions along the stacking direction 104 relative to the longitudinal center plane of the bipolar plate 100 oriented perpendicular to the stacking direction 104, so that a larger cross-section for flow through the coolant distribution area 242 is available.

[0146] The bipolar plate 100 is preferably designed rotationally symmetrically with respect to a rotation through 180° about an axis of rotation extending through the center point of the electrochemically active region 114 of the bipolar plate 100 and parallel to the stacking direction 104 (z direction).

[0147] Therefore, the medium through-opening 130 arranged in the second end region 112b, in particular the anode gas through-opening 134 arranged there, the cathode gas through-opening 136 arranged there and the coolant through-opening 138 arranged there, are preferably constructed and arranged substantially identically to the anode gas through-opening 134, the cathode gas through-opening 136 and the coolant through-opening 138 in the above-mentioned first end region 112a.

[0148] Due to the above and Figures 1 to 9 The bipolar plate 100 shown in the figure is constructed in a multi-layered manner, so the first bipolar plate layer 121 and the second bipolar plate layer 123 must be connected to each other in a fluid-tight manner along the connecting seam 294 to prevent one of the media (anode gas, cathode gas, coolant) to be supplied to the electrochemical device 106 from passing through the gap between the first bipolar plate layer 121 and the second bipolar plate layer 123 to reach the medium through-opening 130 of the other medium, or to reach the medium distribution area or medium flow field of the other medium.

[0149] Such a connection seam 294, which preferably connects the first bipolar plate layer 121 and the second bipolar plate layer 123 to each other by material bonding by welding, in particular laser welding, is arranged, for example, in the region between the outer side of the anode gas sealing rib 142 on the one hand and the anode gas distribution region 170 on the other hand (see in particular Figures 3 to 5 ) and in the region between the cathode gas containment rib 162 on the one hand and the cathode gas distribution region 216 on the other hand (see in particular Fig. 9 ) and in the region between the anode gas containment rib 142 on the one hand and the coolant distribution region 242 on the other hand (see in particular Figure 7 ).

[0150] For example, Figures 3 to 5 It can be seen that support structures 296 are preferably formed on both sides of the connecting seam 294, which support structures are used to support a clamping tool during the production of the connecting seam 294, and the clamping tool is in contact with a support surface 298 of the support structure 296 and optionally also with a flat contact area 300 of the bipolar plate layers 121, 123 located between the support structures 296, so that during the connection process, in particular the welding process, the first bipolar plate layer 121 and the second bipolar plate layer 123 are pressed toward each other with sufficient clamping force. This achieves that before the connection process, a "technical zero gap" of less than 0.03 mm in height is left between the two bipolar plate layers 121, 123 (in the stacking direction 104).

[0151] from Figures 3 to 5It can be seen that the support structure 296 on the side of the connecting seam 294 facing the sealing rib 140 (anode gas sealing rib 142) is formed by the non-directional distribution structure 174 in the form of the distribution protrusion 178 described above.

[0152] These bowl-shaped support structures 302 each have a support surface 298, which is oriented perpendicularly to the stacking direction 104 (z direction) of the bipolar plate 100 and is offset in the stacking direction 104 (z direction) of the bipolar plate 100 relative to a surface 299 of the first bipolar plate layer 121 on which these bowl-shaped support structures 302 are formed by deformation in the contact area 300 (in which the two bipolar plate layers 121 and 123 are in contact with each other in a planar manner) so as to be away from the second bipolar plate layer 123.

[0153] The supporting surface 298 of the cup-shaped supporting structure 302 preferably has a minimum extension a perpendicular to the stacking direction 104 (z direction) of the bipolar plates 100 which is at least 0.1 mm, in particular at least 0.5 mm.

[0154] Furthermore, the minimum extension a of the supporting surfaces 298 of the cup-shaped supporting structures 302 perpendicular to the stacking direction 104 (z direction) of the bipolar plates 100 is preferably at most 3 mm, in particular at most 1.5 mm.

[0155] In addition, from Figure 5 It can be clearly seen that each bowl-shaped support structure 302 has an edge 304, at which the relevant support structure 302 transitions into a flat area of ​​the first bipolar plate layer 121 on which the support structure 302 is constructed, wherein the minimum distance d between the edge 304 of the respective support structure 296 and the center line 306 of the connecting seam 294 (taken perpendicular to the center line 306 of the connecting seam 294) is at most 0.8 mm, in particular at most 0.5 mm, and particularly preferably at most 0.3 mm.

[0156] The maximum distance D between the edge 304 of the respective support structure 296 and the center line 306 of the connecting seam 294 (taken perpendicularly to the center line 306 of the connecting seam 294 ) is preferably at most 5 mm, in particular at most 3 mm, particularly preferably at most 2 mm.

[0157] from Figures 3 to 5 It can also be seen that the supporting structure 296 on the side of the connecting seam 294 facing away from the sealing rib 140 (anode gas sealing rib 142 ) is formed by the oriented distribution structure 172 of the anode distribution area 170 in the form of distribution ribs 176 .

[0158] These rib-like supporting structures 308 also each comprise a supporting surface 298 , whose minimum extension a′ perpendicular to the stacking direction 104 (z direction) of the bipolar plates 100 is preferably at least 0.1 mm, in particular at least 0.5 mm.

[0159] These rib-like supporting structures 308 have their maximum extension along their longitudinal direction 310 perpendicular to the stacking direction 104 (z direction) of the bipolar plates 100 , and this maximum extension is preferably greater than 3 mm, in particular greater than 5 mm.

[0160] These rib-like supporting structures 308 extend transversely to the connecting seam 294, and a distance d' (taken perpendicularly to the center line 306 of the connecting seam 294) between their ends 292 facing the sealing rib 140 (anode gas sealing rib 142) and the center line 306 of the connecting seam 294 is preferably less than 0.8 mm, in particular less than 0.5 mm, and particularly preferably less than 0.3 mm.

[0161] The end 292 of the rib-like support structure 308 is located at the edge 312 of the respective support structure 296, at which edge the support structure 296 transitions into a flat region of the first bipolar plate layer 121 on which the support structure 296 is constructed, wherein the minimum distance d' between the edge 312 of the support structure 296 and the center line 306 of the connecting seam 294 (taken perpendicularly to the center line 306 of the connecting seam 294) is preferably at most 0.8 mm, in particular at most 0.5 mm, and particularly preferably at most 0.3 mm.

[0162] In the operating state of the electrochemical device 106 , adjacent components of the electrochemical cell 102 , such as a gas diffusion layer of the electrochemical cell 102 or a subgasket of a membrane electrode unit, are supported on the support surface 298 of the support structure 296 .

[0163] Therefore, the distance between the support surfaces 298 should not be too large in order to prevent the adjacent components of the electrochemical cell 102 from sagging in the region between the support surfaces 298 and reducing the cross-sectional area through which flow can flow that is respectively present there.

[0164] The following will refer to Fig.10 and Fig.11 A method for materially bonding the first bipolar plate layer 121 and the second bipolar plate layer 123 is explained.

[0165] Here, Fig.10 and Fig.11The schematic diagram relates to the following situation, in which a bowl-shaped support structure 302 is constructed on the first bipolar plate layer 121 on both sides of the connecting seam 294 to be established, and a bowl-shaped support structure 302' is also arranged on the second bipolar plate layer 123 at a position that is essentially identical to the position of the bowl-shaped support structure 302 on the first bipolar plate layer 121 or is only slightly offset relative to these positions.

[0166] The first support structures 296 formed on the first bipolar plate layer 121 each have a first edge 304 at which they transition into a planar region of the first bipolar plate layer 121; and the second support structures 296 ′ formed on the second bipolar plate layer 123 each have a second edge 304 ′ at which they transition into a planar region of the second bipolar plate layer 123, wherein the first edges 304 and the second edges 304 ′ substantially coincide with each other in a projection onto a plane 314 perpendicular to the stacking direction 104 (z direction) of the bipolar plate 100, or are offset from each other by a distance (taken perpendicularly to the longitudinal direction of the respective first edge 304 or the respective second edge 304 ′) of at most 0.5 mm.

[0167] therefore, Fig.10 and Fig.11 The configuration of the support structure 296 shown in FIG. 1 is different from that in FIG. Figures 3 to 5 The specific configuration of the support structure 296 is shown for the region between the anode gas containment rib 142 and the anode gas distribution region 170; however, this does not lead to any fundamental deviations, apart from the specific design of the clamping tool 316 for carrying out the connection method.

[0168] Firstly, the first bipolar plate layer 121 and the second bipolar plate layer 123 are arranged such that they are in contact with one another, preferably over a wide area, at one or more contact regions 300 .

[0169] By means of a plurality of clamping tools 316 , 316 ′, a clamping force is applied to the first bipolar plate layer 121 and the second bipolar plate layer 123 , by which the first bipolar plate layer 121 and the second bipolar plate layer 123 are pressed toward each other in the contact region 300 , so that a “technical zero gap” with a height (extension in the stacking direction 104 ) of less than 0.03 mm remains in the contact region 300 .

[0170] The clamping tool 316 bears against a support surface 298 of the support structure 296 which is offset by a height H in the stacking direction 104 away from the respective other bipolar plate layer 123 relative to a surface 299 of the bipolar plate layer 121 on which the support structure 296 is formed in the contact region 300 .

[0171] Here, the minimum distance d, d' between the edges 304, 304' of the support structures 296, 296' and the center line 306 of the connecting seam 294 is very small, preferably at most 0.8 mm, in particular at most 0.5 mm, and particularly preferably at most 0.3 mm, so that the clamping force introduced into the contact area 300 of the bipolar plate layers 121, 123 along the edges 304, 304' is large enough to produce a stable clamping effect between the bipolar plate layers 121 and 123 in the flat contact area 300.

[0172] from Fig.11 It can be clearly seen from the longitudinal section that in the illustrated embodiment, the clamping tools 316, 316', which are constructed as clamping strips 318 extending in the longitudinal direction, not only abut against the support surface 298 of the support structure 296, but also abut against the flat contact area 300 of the first bipolar plate layer 121 or the second bipolar plate layer 123 in the area between two support structures 296 that follow one another in the longitudinal direction of the clamping tool 316, so as to transmit the clamping force to the bipolar plate layers 121, 123 on these surfaces, respectively.

[0173] While the bipolar plate layers 121 and 123 are subjected to a clamping force by means of the clamping tool 316 , the first bipolar plate layer 121 and the second bipolar plate layer 123 are integrally connected to one another along the connecting seam 294 , preferably by welding, for example by laser welding.

[0174] In this case, a laser for producing the connecting seam 294 by means of laser welding may be arranged on the side of the first bipolar plate layer 121 facing away from the second bipolar plate layer 123 or on the side of the second bipolar plate layer 123 facing away from the first bipolar plate layer 121 .

[0175] After the connecting seam 294 has been produced, the clamping tools 316 , 316 ′ are released from the bipolar plate layers 121 , 123 .

[0176] exist Fig.12 and Fig.13 The second embodiment of the method for materially bonding the first bipolar plate layer 121 and the second bipolar plate layer 123 shown in FIG. Fig.10 and Fig.11 The first embodiment shown in FIG. 1 differs in that no supporting structure 296 ′ is provided for the clamping tool 316 ′ on the left side of the connecting seam 294 to be produced on the second bipolar plate layer 123 , but instead the clamping tool 316 ′ lies against a flat region of the second bipolar plate layer 123 in this region.

[0177] Therefore, from Fig.13It can be seen from the longitudinal section of FIG. 3 that the clamping tool 316 ′ has the same cross section everywhere in its longitudinal direction and therefore has a substantially cuboid shape overall.

[0178] In addition, Fig.12 and Fig.13 The second embodiment of the method for materially bonding the first bipolar plate layer 121 and the second bipolar plate layer 123 shown in FIG. Fig.10 and Fig.11 The first exemplary embodiment shown in FIG. 1 is identical to that shown in FIG. 1 , to which reference is made to the above contents in this regard.

[0179] from Figure 6 and Fig. 9 It can be seen that the cathode gas sealing rib 162 is also surrounded by the closed connecting seam 294 .

[0180] from Fig. 9 It can be clearly seen that, as in the case of the connecting seam 294 surrounding the anode gas sealing rib 142 described above, support structures 296 for supporting the clamping tool 316 during the production of the connecting seam 294 are provided on both sides of the connecting seam 294.

[0181] Here, the support structure 296 arranged on the side of the connecting seam 294 facing the sealing rib 140 (cathode gas sealing rib 162) is constructed as a bowl-shaped support structure 302 formed into the second bipolar plate layer 123, while the support structure 296 arranged on the side of the connecting seam 294 facing away from the sealing rib 140 (cathode gas sealing rib 162) is constructed as a convex rib-shaped support structure 308 formed into the second bipolar plate layer 123, and the longitudinal direction 310 of the convex rib-shaped support structure extends transversely to the center line 306 of the connecting seam 294. Preferably, the angle α between the longitudinal direction 310 and the center line of the connecting seam 294 is greater than 75°, especially greater than 80°.

[0182] In addition, the support structure 296 on both sides of the connection seam 294 surrounding the cathode gas sealing rib 162 is consistent with the support structure 296 on both sides of the connection seam 294 surrounding the anode gas sealing rib 142 in terms of structure, function and manufacturing method, and reference is made to the above content in this regard.

[0183] The method for materially connecting the first bipolar plate layer 121 and the second bipolar plate layer 123 along the connecting seam 294 surrounding the cathode gas sealing rib 162 (except that the first bipolar plate layer 121 and the second bipolar plate layer 123 are interchanged) is the same as that of the above reference. Figures 10 to 13 The method shown in is consistent with that shown in. Reference is made to the above content in this regard.

[0184] from Figure 6 and Figure 7It can be seen that on the cathode side of the bipolar plate 100 , along the connection seam 294 surrounding the anode gas sealing rib 142 , a support structure 296 extending parallel to the connection seam 294 is provided on the side facing away from the sealing rib (anode gas sealing rib 142 ).

[0185] Such a rib-like supporting structure 308 can also be used to support the clamping tool 316 during the production of the connecting seam 294 .

[0186] Figures 14 to 16 A second embodiment of the bipolar plate 100 is shown, in which the connecting seam 294 along which the first bipolar plate layer 121 and the second bipolar plate layer 123 are materially connected to each other extends at least in sections parallel to the rib 320, and a plurality of medium outlet openings 324 are arranged on the flanks 322 of the rib facing the connecting seam 294.

[0187] On the side of the connecting gap 294 facing away from the pressure ribs 320 , a medium flow field 326 is arranged which has ribs 328 extending at an angle of approximately 45° with respect to the longitudinal direction of the connecting gap 294 .

[0188] A medium flow channel 330 is formed between each two ribs 328 , into which the medium flowing out of the medium outlet openings 324 of the pressure ribs 320 flows.

[0189] Here, in Fig.14 The medium flow field 326 shown in FIG. 1 may be, for example, the anode gas flow field 116 of the bipolar plate 100 .

[0190] Fig.15 The bipolar plate 100 is shown in Fig.14 The rear side in the region shown in FIG. 1 and thus shows a medium flow field 326 ′ which is associated with a further medium to be supplied to the electrochemical device 106 .

[0191] if Fig.14 The anode gas flow field 116 is shown. Fig.15 The cathode gas flow field 118 of the bipolar plate 100 is shown.

[0192] However, the anode side and the cathode side of the bipolar plate 100 may also be switched with each other.

[0193] from Fig.15 It can be seen that the rib 328 of the medium flow field 326 ′ extends at least in sections parallel to the connecting seam 294 .

[0194] Therefore, the medium channel 330' of the medium flow field 326' and the medium channel 330 of the medium flow field 326 intersect, thereby forming a series of local resting centers 332 parallel to the connecting seam 294, at which the first bipolar plate layer 121 and the second bipolar plate layer 123 support each other, so that when the bipolar plate layers 121 and 123 are compressed, force balance can occur at these local resting centers 332, and the protrusions adjacent to these local resting centers 332 in the first bipolar plate layer 121 or the second bipolar plate layer 123 can be used as a support structure 296 for supporting the clamping tool 316 (see Fig.16 ).

[0195] Therefore, even in this design of the bipolar plate 100, reference Figures 10 to 13 The method described for the integrally bonded connection of the first bipolar plate layer 121 and the second bipolar plate layer 123 by means of clamping tools 316 is supported on a support structure 296 formed into the first bipolar plate layer 121 or the second bipolar plate layer 123 .

Claims

1. A method for materially connecting a first bipolar plate layer (121) and a second bipolar plate layer (123) of a bipolar plate (100) for an electrochemical cell (102) of an electrochemical device (106), the electrochemical device comprising a plurality of electrochemical cells (102) following one another in a stacking direction (104), the method comprising the following items: - placing the first bipolar plate layer (121) and the second bipolar plate layer (123) in contact at one or more contact areas (300) of the bipolar plate layers (121, 123); - applying a clamping force to the first bipolar plate layer (121) and the second bipolar plate layer (123) by means of one or more clamping tools (316); and - connecting the first bipolar plate layer (121) and the second bipolar plate layer (123) together in a material-locked manner along the connecting seam (294); It is characterized in that At least one clamping tool (316) is supported on a support surface (298) of at least one support structure (296) of at least one of the bipolar plate layers (121, 123), wherein the support surface (298) of the support structure (296) is offset in the stacking direction (104) relative to a surface (299) of the bipolar plate layer (121, 123) on which the support structure (296) is constructed in the contact area (300) in a manner away from the corresponding other bipolar plate layer (123, 121).

2. The method according to claim 1, characterized in that At least one clamping tool (316) is supported on a plurality of support surfaces (298) of a plurality of different support structures (296) and on a plurality of contact areas (300) of bipolar plate layers (121, 123) located between the support structures (296).

3. The method according to any one of claims 1 or 2, characterized in that At least one first clamping tool (316) is supported on at least one first support structure (296) constructed on the first bipolar plate layer (121), and at least one second clamping tool (316') is supported on at least one second support structure (296') constructed on the second bipolar plate layer (123).

4. The method according to claim 3, characterized in that The first support structure (296) has a first edge (304) at which the first support structure (296) transitions into a planar region of the first bipolar plate layer (121), and the second support structure (296') has a second edge (304') at which the second support structure (296') transitions into a planar region of the second bipolar plate layer (123), wherein the first edge (304) and the second edge (304') substantially coincide with each other or deviate from each other by a distance of at most 0.5 mm in a projection onto a plane (314) perpendicular to the stacking direction (104).

5. The method according to any one of claims 1 to 4, characterized in that At least one supporting structure (296) is formed at a location of one of the bipolar plate layers (121, 123) that is opposite a flat region of the respective other bipolar plate layer (123, 121) that is not provided with the supporting structure (296).

6. The method according to any one of claims 1 to 5, characterized in that The support surface (298) of at least one support structure (296) has a minimum extension (a) perpendicular to the stacking direction (104) of at least 0.1 mm.

7. The method according to any one of claims 1 to 6, characterized in that The support surface (298) of the at least one support structure (296) has a minimum extension (a) perpendicular to the stacking direction (104) of at most 3 mm.

8. The method according to any one of claims 1 to 7, characterized in that The support surface (298) of at least one support structure (296) has a maximum extension perpendicular to the stacking direction (104) of greater than 3 mm.

9. The method according to any one of claims 1 to 8, characterized in that At least one support structure (296) has an edge (304, 312) at which the support structure (296) transitions into a flat region of the bipolar plate layer (121, 123) on which the support structure (296) is constructed. Wherein, the minimum distance (d) between the edge (304, 312) of the support structure (296) and the center line (306) of the connection seam (294) is at most 0.8 mm.

10. The method according to any one of claims 1 to 9, characterized in that At least one support structure (296) has an edge (304) at which the support structure (296) transitions into a flat region of the bipolar plate layer (121, 123) on which the support structure (296) is constructed. Wherein, the maximum distance (D) between the edge (304) of the support structure (296) and the center line (306) of the connection seam (294) is at most 5 mm.

11. The method according to any one of claims 1 to 10, characterized in that At least one supporting structure (296) is designed to be circular or elliptical in a plan view along the stacking direction (104).

12. The method according to any one of claims 1 to 11, characterized in that At least one supporting structure (296) is configured as a rib.

13. The method according to claim 12, characterized in that At least one rib-like supporting structure (308) extends at least in sections substantially parallel to the connecting seam (294).

14. The method according to any one of claims 12 or 13, characterized in that A plurality of rib-like supporting structures (308) extend transversely to the connecting seam (294) and end at a distance (d') of less than 0.8 mm from a center line (306) of the connecting seam (294).

15. A bipolar plate for an electrochemical cell (102) of an electrochemical device (106), the electrochemical device comprising a plurality of electrochemical cells (102) following one another in a stacking direction, the bipolar plate (100) comprising the following items: - a first bipolar plate layer and a second bipolar plate layer which are materially connected to each other along a connecting seam (294) in a contact region (300) of the bipolar plate layers (121, 123); in, At least one support structure (296) is respectively constructed on the first bipolar plate layer (121) and / or the second bipolar plate layer (123), wherein a support surface (298) of at least one of the support structures (296) is offset in the stacking direction (104) relative to a surface (299) of a bipolar plate layer (121, 123) on which the support structure (296) is constructed in the contact region (300) in a manner away from the corresponding other bipolar plate layer (123, 121); and The at least one support structure (296) has an edge (304, 312) at which the support structure (296) transitions into a flat region of the bipolar plate layer (121, 123) on which the support structure (296) is constructed, wherein the minimum distance (d, d') between the edge (304, 312) of the support structure (296) and the center line (306) of the connecting seam (294) is at most 0.8 mm.

16. An electrochemical device comprising a plurality of electrochemical cells (102), which follow one another in a stacking direction (104) and each comprise a bipolar plate (100) according to claim 15.

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