Electrode plate with integrated current transmitter structure, and electrode pack unit

Abstract

The invention relates to an electrode plate for a stack structure of an electrochemical reactor, containing a plate body (6) and an integrated current transmitter structure (7) which is an integral part of the plate body and consists of at least one current transmitter body that protrudes from a plate main part (6b) of the plate body in a current transmitter region (6a) of the plate body and contains a plateau surface (9), which is arranged at a distance to the plate main part of the plate body and is designed to contact a bipolar plate of the stack structure, and a connecting structure, which connects the plateau surface to an edge (10) of the current transmitter region. The invention also relates to an electrode pack unit equipped with such an electrode plate. According to the invention, the current transmitter body forms a current transmitter basket (8), which is made of a shaped region of the plate body and comprises a compression-resistant and electrically conductive basket lateral wall (8a) that forms a connection structure. The invention also relates to a use in electrolysis reactors or fuel cell reactors for example.

Description

[0001] Electrode plate with integrated current transformer structure and

[0002] Electrode packing unit

[0003] The invention relates to an electrode plate for a stacked structure of an electrochemical reactor according to the preamble of claim 1 and to an electrode packing unit according to the preamble of claim 9 for a stacked structure of an electrochemical reactor.

[0004] Electrode plates and electrode packing units of this and similar types are used, for example, in block stack structures of electrolysis reactors, e.g., for the alkaline electrolysis of water under or without pressure, and fuel cell reactors. In these reactor designs, also referred to as blocks or stacks, the individual components are stacked on top of one another to form a plurality of electrically coupled reactor cells, i.e., electrolysis cells or fuel cells. These components include, in particular, cell membranes, bipolar plates, and electrode plates for providing the electrolyte used as the anode orElectrode surfaces acting as a cathode, current transfer structures between the bipolar plate on the one hand and an adjacent electrode plate on the other, cell frames in which the plate-shaped components are held at the edges, circumferential seals, end plates, and bracing devices for the pressure-tight and liquid-tight bracing of all block components into a block. Block stack structures used in practice typically consist of identical, stacked cell arrangements with approximately 5 to approximately 350 cells. Various stack structures for such electrochemical reactors are described in the patents US 4,124,478, US 4,339,324, US 4,758,322, US 6,117,287, and US 6,555.267 B1 and EP 2 898 115 B1 as well as the published patent applications US 2002 / 0110719 A1 , US 2002 / 0175072 A1 , US 2003 / 0188966 A1 , US 2005 / 0019642 A1 , US 2009 / 050472 A1 , US 2010 / 0136455 A1 , US 2010 / 0187102 A1 , JP 2010-033788 A, DE 1 643 042, DE 27 29 640 A1 , DE 10 2007 005 232 A1 and DE 102 59 386 A1. In such a block stack, a membrane, an electrode plate, a current transformer structure, a bipolar plate, another current transformer structure, another electrode plate, and then another membrane are arranged in a repeating arrangement. The stacking sequence of electrode plate, current transformer structure, bipolar plate, current transformer structure, and electrode plate, which is located between each pair of membranes, is referred to here as the electrode pack unit.In corresponding embodiments, this electrode packing unit is preassembled as a separate structural unit, whereby an electrode packing unit and a membrane unit containing the membrane are alternately stacked to form the reactor stack. However, such preassembly is not mandatory for the invention; the electrode packing unit considered here can also be formed without preassembly in corresponding alternative embodiments, i.e., only as a loose electrode packing unit during the formation of the block stack.

[0005] The bipolar plate is fluid-tight and, in particular, gas-tight and separates the reaction fluids involved, including the product gases, between two cells. The electrode plates and the current transfer structures are designed to be fluid-permeable so that the reaction fluids can flow in the spaces between the bipolar plate on the one hand and each of the two adjacent electrodes on the other and reach the membrane. The electrode plates are conventionally formed, for example, from perforated sheet elements, whereby the remaining metallic electrode surface should remain sufficiently large compared to the overall extent of the electrode plates, i.e. the transparency, i.e. the opening, should be only as small as necessary. The current transfer structures serve, as their name suggests, to transmit electrical current between the bipolar plate on the one hand and the electrode plates adjacent to the bipolar plate on both sides, of which, for example,one acts as an anode and the other as a cathode.

[0006] Conventionally, the current transfer structures are usually prefabricated as separate components from the electrode plates and then contacted, or electrically connected, to an electrode plate on the one hand and a bipolar plate on the other. Various types of such separate current transfer structures are common. The first type is flexible or elastic metal knits or metal fabrics. This type of current transfer structure can withstand the compressive loads that occur during stack assembly and / or operation to a high degree. However, it has the difficulty that the contact points of the knit or fabric to the adjacent plates are not predefined. This can lead to an undefined current transfer distribution and / or an uneven current density load on the electrode plates or the electrode surfaces formed by them.Another type of current transfer structure is formed from preformed expanded metal elements or perforated sheet metal elements or similar. This type of current transfer structure can provide defined contact points to the electrode surfaces and the bipolar plates, but has the difficulty that these comparatively rigid components can only slightly elastically yield to the aforementioned pressing pressures. Furthermore, this type can lead to high current density loads at certain points if the total contact area between the current transfer structure on the one hand and the electrode plate and / or bipolar plate on the other is kept relatively small.

[0007] To save material and weight and to disturb the permeability of the space between the bipolar plate and the electrode plate or membrane for the reaction fluids as little as possible.

[0008] In the type of electrode plates considered in the present invention, the current transfer structures are an integral part of the electrode plates, in that the respective current transfer structure is a one-piece component of the plate body and consists of at least one current transfer body, which is formed in a current transfer region of the plate body so as to protrude from a main plate part of the plate body and includes a plateau surface spaced from the main plate part and designed for contacting a bipolar plate of the stack structure, and a connecting structure connecting the plateau surface to an edge of the current transfer region. As a rule, this plate body has outside the current transfer region, iein the region of the main plate part, a substantially planar shape, wherein the main plate part defines a plane of the plate body in which the plate body predominantly lies, usually also referred to as the plate plane or main plane of the plate body or of the plate or electrode plate. Patent specification EP 3 770 303 B1 discloses such an electrode plate of the type mentioned at the outset with an integrated current transformer structure and an electrode packing unit equipped therewith, wherein the connecting structure of the current transformer body is formed by a plurality of current transformer arms which extend in a meandering course from the plateau surface to the main plate part and which.

[0009] The plateau surface is held elastically and flexibly to the main plate part perpendicular to its surface plane. The current transformer arms of the current transformer body can be formed from the plate body in the relevant current transmission area by punching them out, connected to the plateau surface, and by subsequent forming, pushing the plateau surface out of the plane of the plate body.

[0010] The invention is based on the technical problem of providing an electrode plate and an electrode packing unit equipped therewith of the type mentioned above, which offer advantages over the above-mentioned prior art, particularly with regard to the current transfer structures used. The invention solves this problem by providing an electrode plate having the features of claim 1 and an electrode packing unit having the features of claim 9. Advantageous developments and / or refinements of the invention are specified in the subclaims, the wording of which is hereby incorporated by reference into the description. This includes, in particular, all embodiments of the invention that result from the combinations of features defined by the references in the subclaims.

[0011] In the electrode plate according to the invention, the current transformer body is a current transformer basket formed by a deformed region of the plate body with a pressure-resistant and electrically conductive basket side wall which forms the connecting structure.

[0012] The term current transmitter basket is, as the name suggests, a structure with a basket shape designed to transmit electrical currents, ie a structure with a base and a side wall extending circumferentially from this, which thus has a closed cross-sectional edge, such as a circular, oval or otherwise round or a polygonal cross-section.

[0013] In other words, the current transformer body has a basket shape with the plateau surface as the basket base and the basket side wall as a mechanical and electrically conductive connection between the edge of the plateau surface and the edge of the relevant current transmission area of ​​the plate body or its main plate part. The deformation of the relevant plate body area into the current transformer basket can in particular be of a mechanical nature, specifically by stretching the plate material and / or introducing and widening slots or recesses. By appropriately specifying the design of the current transformer structure or current transformer baskets, such as with regard to the length and spacing of slots or recesses, relatively large embossing depths, i.e., projection heights or basket heights of the current transformer baskets, can also be realized if required.

[0014] In this case, the characterization of pressure-resistant means that the current transformer basket and in particular its side wall can withstand the pressures that can act on it during the construction of the stack for the intended use in the corresponding electrochemical reactor and during subsequent reactor operation, so that these pressure loads do not lead to permanent, inelastic or temporary, elastic deformations of the basket side wall.

[0015] Thus, in the electrode plate according to the invention, the current transmitter structure from the plate surface of the electrode plate is compression-resistant and thus non-resilient, and accordingly forms a special, functional shape made of the electrode plate material in this deformed region of the plate body of the electrode plates. The shape, size and height of this shape forming the current transmitter structure can be specifically specified, and due to the compression stiffness of the basket side walls, desired distances between the bipolar plate on the one hand and the adjacent electrode plates in the stack structure on the other hand can be specified and adjusted during assembly into blocks or stacks and maintained during operation. Due to these properties, the electrode plate according to the invention has significant advantages. The structure of the electrode plate as a plate body with one or more formed or...The use of flared current exchanger baskets, pressed out of its plate plane, as an integrated current exchanger structure simplifies automated production and enables easy adaptation of the electrode plate to a given cell frame design. The rigid, pressure-resistant design of the current exchanger basket, and in particular of its basket side wall, enables the absorption and transmission of forces, such as weight forces and operational compressive forces, when forming the electrode packing unit or the electrochemical stack or block of the reactor in which the electrode plate is used. As a result, the surrounding cell frames, in which the electrode plates and the other stack components are held at the edges, do not necessarily have to be designed to support the weight of stacked electrode packing units themselves.With the help of the pressure-resistant current transformer baskets, the stack of electrode packing units is able to support its own weight without the current transformer structure deforming due to the weight forces.

[0016] The pressure-resistant, pressure-resistant contouring of the current transfer baskets, in conjunction with a force-fitting or material-fit connection to a bipolar plate, provides a stable metallic structure suitable for force transmission or weight absorption, so that the surrounding cell frames can be manufactured from more flexible plastic materials, for example, which offers a significant advantage when assembling blocks or stacks of many cells. Due to the pressure-resistant, solid design of the current transfer baskets, the current transfer structure in the electrode plate according to the invention can thus be used as the component in the block or stack that ensures compliance with the necessary clearances to protect the bipolar plate membrane from damage and maintains the gas / liquid spaces required for operation in the cells.A particular advantage of the electrode plate according to the invention is that the current transmission cross-section effectively available for electrical current conduction through the current transformer structure can be kept comparatively large, since it is not necessary to punch out or otherwise remove a significant portion of material from an associated plate blank to manufacture the electrode plate with the integrated, exposed current transformer structure. At the same time, the relatively high remaining material content of the current transformer basket has the advantage, compared to current transformer structures in which a significant portion of the plate material is punched out of the plate body or removed in some other way, that a relatively large amount of electrode surface is retained for the effective electrode function, such as gas production during water electrolysis.The compressive stiffness of the side walls of the current exchanger baskets enables precise shaping of the current exchanger baskets and the setting of a desired, predeterminable, uniform, fixed distance between the electrode plate and the adjacent bipolar plate in the reactor stack or in the electrode packing unit. The compressive stiffness of the current exchanger basket prevents recovery or re-deformation of the current exchanger structure due to continuous or time-varying mechanical loads, which can occur with elastically flexible current exchanger structures.

[0017] The structure or contour design of the current transformer basket protruding from the plate body can be easily adapted to the specified contour of the electrode plate. For example, the contour or cross-section of the current transformer basket can be circular, oval, elliptical, or polygonal, i.e., the current transformer basket can have a round bowl shape or a square truncated pyramid shape. This enables optimal adaptation to the external shape of the electrode plate, which can, for example, be circular, oval, rectangular, or otherwise polygonal. Preferably, several current transformer baskets are arranged across the electrode plate in such a way that the current density distribution is as uniform as possible across the electrode plate during operation.

[0018] The plateau surface, i.e., the base of the current transformer basket, is preferably flat, which generally promotes optimal electrical contact between the current transformer basket and the bipolar plate. The connection between the plateau surface and the bipolar plate can be realized in such a way that reliable, permanent electrical current transmission at the desired current density is possible without increasing electrical contact resistance, e.g., due to oxidation and / or electrical heat in the contact surface.

[0019] In a further development of the invention, the basket side wall has an opening structure, i.e., one or more openings, particularly in the form of slots or recesses. When the corresponding plate body region is formed into the current transformer basket, the openings can expand, whereby, if necessary, the material thickness in the formed region can be kept essentially constant or, at least, material weakening in this region can be kept relatively small, so that the material cross-section of the current transformer basket effectively available for current conduction can then be kept essentially the same size as the plate cross-section in this region prior to forming.The widened openings can facilitate non-destructive exposure of the desired contour of the current transfer basket with the formation of a preferably flat plateau surface. They can also be used for liquid and / or gas transport through the electrode plate, as in the case of water electrolysis, for the removal of gas bubbles to the back of the electrode plate toward the bipolar plate and for the supply of electrolyte to the front of the electrode plate. This reduces the transparency or opening for the remaining part of the electrode plate outside the current transfer basket areas, which is required for gas / liquid transport into the space between the back of the electrode plate and the bipolar plate, as well as to the gas-producing front of the electrode plate, and increases the reactive electrode surface of the electrode plate.Depending on the required current load of the electrode plate, it may be possible to dispense with extensive perforation of the electrode plate outside the area of ​​the current transfer baskets or with additional surface recesses distributed across the electrode plate. In alternative designs, the basket side wall can be completely closed if no slots or other openings in the basket side wall are required for the respective application or basket formation process. The alternative, closed side wall design has a comparatively high current carrying capacity or current transmission capability.

[0020] In one embodiment of the invention, the opening structure has an opening area of ​​at most 45% of the total area of ​​the basket side wall. In more specific designs, the opening area is only 30% or less, or even only 10% or less. It has been shown that an opening structure with such an opening area offers an optimal compromise between the current transmission capacity and the fluid / gas permeability, depending on the application. An opening area of ​​around 45% allows a correspondingly large amount of gas / liquid to pass through the current exchanger basket; an opening area of ​​around 30% provides a correspondingly somewhat lower gas / liquid passage, whereas an opening area of ​​only approx. 10% or, for example,In the range between 5% and 20%, correspondingly less gas / liquid can pass through, but the electrical current transmission capacity and compressive strength of the current transmitter basket are correspondingly greater. In alternative designs, the opening area of ​​the opening structure of the basket side wall can also be over 45% if this is favorable for the respective application.

[0021] In one embodiment of the invention, the opening structure has at least one axial slot opening, which extends with a main directional component in the basket axial direction, i.e., entirely or at least predominantly in this direction. The introduction of such slot openings is relatively easy to implement in terms of manufacturing technology and proves to be advantageous with regard to the expansion behavior during forming or unfolding of the current transformer basket. The axial slot openings in the current transformer basket are formed by introducing correspondingly radially extending slots into the plate body before forming the corresponding region into the current transformer basket. In alternative embodiments, the basket side wall does not have an opening structure with an axial slot opening.

[0022] In one embodiment of the invention, the opening structure has at least one transverse slot opening, which extends with a main directional component in the circumferential direction of the basket. It has been shown that the transverse slot opening is easy to realize in terms of manufacturing technology, in particular by slitting the relevant region of the plate body before forming or extending the current transformer basket in the circumferential direction, and is favorable in terms of its expansion behavior when extending the current transformer basket. In alternative embodiments, the basket side wall does not have an opening structure with a transverse slot opening if this is advantageous for corresponding applications.

[0023] In one embodiment of the invention, the opening structure has at least one flap opening formed by slitting and bending a corresponding plate body region on one side. Shaping the corresponding opening of the opening structure as such a flap opening can assist in the removal of gases from the front side of the electrode plate to its rear side. In alternative embodiments, the basket side wall does not have an opening structure with a flap opening if this is not required for the application in question.

[0024] In a further development of the invention, the current transmitter basket has a basket diameter of no more than 60 mm at its edge, i.e. at its transition to the adjacent flat plate body region of the electrode plate on the side opposite the basket base or the plateau surface. In a corresponding embodiment, the basket diameter is no more than 40 mm. It has been shown that this dimensioning of the current transmitter basket is optimal for many applications. The relatively small basket diameter of no more than approx. 60 mm or in many cases only approx. 40 mm or less, e.g. only approx. 30 mm to approx. 35 mm, can contribute to keeping the proportion of electrode-active flat plate surface in relation to the total surface of the electrode plate relatively large. Nevertheless, a relatively large projection depth, i.e. axial height, of the current transmitter basket can be provided, e.g. a projection depth of approx. 15 mm or more generally between approx. 3 mm and approx. 25 mm.In alternative designs, current transformer baskets with a basket diameter of more than 60 mm are used if this proves to be advantageous for corresponding applications.

[0025] In a further development of the invention, the current transformer basket is a deep-drawn structure, i.e., the current transformer basket is formed as a structure that is molded out of the plate body by a conventional deep-drawing process. This represents an advantageous manufacturing implementation of the current transformer basket. As an alternative to providing the current transformer basket by means of a deep-drawing process, the current transformer basket can be formed by another conventional, comparable, preferably mechanical forming process, or alternatively, another conventional structure-forming or shaping process, such as a casting process, which produces the same structural result.

[0026] The electrode packing unit according to the invention includes a fluid-tight bipolar plate, a first electrode plate and a second electrode plate which are arranged on opposite sides of the bipolar plate, as well as a first current transformer structure for electrically and mechanically connecting the bipolar plate to the first electrode plate and a second current transformer structure for electrically and mechanically connecting the bipolar plate to the second electrode plate, wherein the first electrode plate is an electrode plate according to the invention and the first current transformer structure is formed by the integrated current transformer structure of the first electrode plate and / or wherein the second electrode plate is an electrode plate according to the invention and the second current transformer structure is formed by the integrated current transformer structure of the second electrode plate.By stacking several such electrode packing units, a corresponding stack structure of an electrochemical reactor, in particular an electrolysis reactor or a fuel cell reactor, can be realized.

[0027] In the electrode packing unit according to the invention, the respective electrode plate is electrically and mechanically, in particular materially, connected to the bipolar plate via the current transfer basket(s). The current transfer basket(s) with their pressure-resistant basket side walls ensure that a defined, predeterminable distance between the bipolar plate and the respective electrode plate is maintained. The properties and advantages mentioned above apply analogously to the electrode packing unit through the use of the respective electrode plate according to the invention.

[0028] Optionally, when manufacturing the electrode plates from uncoated sheet metal, the various electrode surfaces of the electrode plates of the electrode packing unit can be completely electroplated by immersing the electrode packing unit in a dedicated electroplating bath. By immersing the electrode plates and bipolar plate as individual parts in the unassembled state or by covering individual parts in the assembled state, specific parts of the electrode packing unit can be electroplated. Alternatively, it is also possible to coat the electrode plates after assembly of the electrode packing unit, for example, using a plasma coating process. This can prevent backspraying of the electrode welding surfaces used to fix them to the bipolar plate, thus optimizing the weld seam connection.In addition, part of the thermal energy introduced during the coating process can be dissipated to the outside via the bipolar plate, which can prevent or minimize thermal distortion of the electrode plate.

[0029] In a further development of the invention, at least one plateau surface of the first current transfer structure is arranged on the bipolar plate, overlapping a plateau surface of the second current transfer structure. This design has the advantage that the connection points arranged in alignment on both sides of the bipolar plate can be produced simultaneously, for example, using two welding electrodes acting on the corresponding plateau surfaces of the current transfer cage. This means that the welding electrodes directly connect the three metal layers with a weld point. Alternatively, such an aligned arrangement of connection points can be omitted if this is advantageous for corresponding applications.

[0030] In a further development of the invention, at least one plateau surface of the first current transfer structure is arranged on the bipolar plate offset from the plateau surfaces of the second current transfer structure, and / or at least one plateau surface of the second current transfer structure is arranged offset from the plateau surfaces of the first current transfer structure with the bipolar plate. This implementation is suitable for applications in which a spatially offset connection, in particular welding, of the plateau surfaces of one electrode plate to the bipolar plate is preferred over that of the plateau surfaces of the other electrode plate to the bipolar plate. Such offset welding of the current transfer baskets of the two electrode plates to the bipolar plate can reduce thermal distortion, which can occur particularly when using relatively thin bipolar plates.This offset welding allows the heat input to be distributed more evenly across the bipolar plate surface. If this is not a problem in the specific application, all connection points can alternatively be aligned on the bipolar plate.

[0031] In a further development of the invention, a distance of the plate main part of the first electrode plate from the bipolar plate can be determined by the distance of the plateau surfaces of the first current transformer structure from the plate main part of the first electrode plate, and / or the distance of the plate main part of the second electrode plate from the

[0032] The bipolar plate can be defined by the distance between the plateau surfaces of the second current transfer structure and the main plate part of the second electrode plate. This has the advantage that the distances between the main plate part of the respective electrode plate and the bipolar plate can be set differently if necessary. This is achieved by extending the current transfer baskets for one electrode plate with a greater extension depth than the current transfer baskets for the other electrode plate. This allows, for example, inaccuracies during assembly of the electrode packing unit, such as an inaccurate positioning of the electrode packing unit or a bipolar plate membrane in a cell frame, to be compensated for by selecting different distances between the bipolar plate on the one hand and the cathodic or anodic electrode plate on the other.

[0033] Advantageous embodiments of the invention are illustrated in the drawings. These and other embodiments of the invention are explained in more detail below. In the drawings: Fig. 1 shows a schematic partial sectional view of an electrode packing unit with a bipolar plate and electrode plates arranged on both sides.

[0034] Fig. 2 is a perspective top view of one side of the electrode packing unit of Fig. 1, Fig. 3 is a perspective top view of one of several current transfer baskets of the electrode plates,

[0035] Fig. 4 shows the view of Fig. 2 for a variant of the electrode plate with modified current transfer baskets, Fig. 5 shows a detailed view of an area V of Fig. 4,

[0036] Fig. 6 the view of Fig. 3 for another modified current transformer cage and

[0037] Fig. 7 is a partial perspective view of an electrode plate design with flap opening pattern.

[0038] The electrode packing unit shown schematically in Fig. 1 with its components of interest here is intended and suitable for a stacked structure of an electrochemical reactor, in particular an electrolysis reactor or a fuel cell reactor, specifically for water electrolysis, for example. The stacked structure comprises a block or stack of several such stacked electrode packing units, as is known per se to the person skilled in the art. The electrode packing unit shown has a conventional structure with a fluid-tight

[0039] Bipolar plate 1 of conventional type, a first electrode plate 2 arranged on one side of the bipolar plate 1, and a second electrode plate 3 arranged on the other side of the bipolar plate 1. Furthermore, the electrode package unit includes a first current transfer structure 4, by which the bipolar plate 1 is electrically and mechanically connected to the first electrode plate 2, and a second current transfer structure 5, by which the bipolar plate 1 is electrically and mechanically connected to the second electrode plate 3.

[0040] In the example shown in Fig. 1, both electrode plates 2, 3 are each realized as an electrode plate according to the invention for a stacked structure of an electrochemical reactor, such as an electrolysis reactor or a fuel cell reactor. Figs. 2 to 7 show various inventive embodiments for the respective electrode plate 2, 3. In alternative embodiments not shown, only one of the two electrode plates 2, 3 has the inventive structure. In the inventive embodiment, the electrode plate 2, 3 comprises a plate body 6 and an integrated current transformer structure 7, which is an integral part of the plate body 6. The current transformer structure 7 consists of at least one current transformer body, which is formed as a current transformer basket 8 in a current transformer region 6a of the plate body 6, protruding from a main plate part 6b of the plate body 6, in that the current transformer body has a basket-shaped configuration.The main plate part 6b designates the remaining part of the plate body 6 outside the current transmission area 6a, while the current transmission area 6a designates the part of the plate body 6 in which the current transmitter body(s) are formed. The main plate part 6b is completely or at least essentially flat, and its associated flat surface thus lies essentially in a plane E defined thereby. P of the plate body 6. It can be designed in a technically suitable manner with the help of the current to be transmitted and the specific conductivities of the current transmitter baskets, the bipolar plate and the connecting material used, e.g. for the selected welding material, as is known to the person skilled in the art.

[0041] The current transmitter body or current transmitter basket 8 is formed by the correspondingly formed current transmission area 6a of the plate body 6 and includes a plateau surface 9 spaced from the plate main part 6b of the plate body 6, designed for contacting the bipolar plate 1 of the stack structure, and a connecting structure connecting the plateau surface 9 to an edge 10 of the current transmission area 6a, which thereby also forms an edge of the current transmitter basket 8, which is formed by a pressure-resistant and electrically conductive basket side wall 8a of the current transmitter basket 8. The distance of the plateau surface 9 from the plate main part 6b of the plate body 6 corresponds to a basket height KH of the current transmitter basket 8, i.e. the distance of the basket base functioning as the plateau surface 9 from the plane E P of the plate body 6 lying basket edge 10.

[0042] Due to the use of two electrode plates according to the invention for the first and second electrode plates 2, 3 of the electrode packing unit shown in Fig. 1, its first current transformer structure 4 is formed by the integrated current transformer structure 7 of the first electrode plate 2, and its second current transformer structure 5 is formed by the integrated current transformer structure 7 of the second electrode plate 3.

[0043] In the example shown in Fig. 1, the two electrode plates 2, 3 of the electrode packing unit are of identical design; in alternative implementations not shown, they are of different designs, e.g. using different current transfer baskets 8 for the two electrode plates 2, 3. The use of different current transfer baskets for the two electrode plates 2, 3 can be expedient, for example, in water electrolysis, since during the gas generation process, in principle only half the gas volume of the hydrogen side is generated on the oxygen side. Furthermore, in the examples shown, all current transfer baskets 8 of the respective electrode plate 2, 3 are identical. In alternative embodiments, differently shaped current transfer baskets 8 can be used for one electrode plate.

[0044] In the illustrated embodiments, the electrode plates 2, 3 and the bipolar plate 1, and thus also the electrode packing unit, have a circular shape. In alternative embodiments, any other shape can be chosen, e.g., an oval, rectangular, or otherwise polygonal shape.

[0045] In the exemplary embodiments shown, the respective electrode plate 2, 3 has a plurality of current transformer baskets 8 in a uniformly distributed, e.g., concentric arrangement across the surface area of ​​the electrode plate 2, 3, as can be seen from Figs. 2 and 4, wherein the distribution of the current transformer baskets 8 is expediently adapted to the shape of the electrode plate 2, 3 in order to ensure the most uniform current transport possible across the surface area of ​​the electrode plate 2, 3. In corresponding embodiments, for example, between ten and fifty current transformer baskets 8 are arranged on an electrode plate surface area of ​​between two thousand and three thousand square centimeters.

[0046] In advantageous embodiments, the basket side wall 8a has an opening structure 11, as is the case in the exemplary embodiments shown. The opening structure 11 contains one or preferably a plurality of openings, which are preferably formed by introducing corresponding slots or recesses into the current transmission region 6a of the plate body 6 prior to forming, e.g. by laser cutting, which then widen somewhat during the forming of the current transmission region 6a into the current transmitter basket 8, as a result of which the material thickness in the formed region can be kept essentially constant or at least does not need to be reduced very significantly. The forming of the current transmitter basket 8 from the material of the electrode plate 2, 3 orThe plate body 6, or more precisely, an associated plate blank, therefore results in no, or at least only a relatively small, loss of effective electrode material area of ​​the electrode plate 2, 3 or the plate body 6. Specifically, the loss of effective electrode material area can be limited to a maximum of 3% to 5%. In comparison, with conventional electrode plates with an integrated current transfer structure, the loss is typically well over 10%.

[0047] In advantageous realizations of the electrode plate 2, 3, the opening structure 11 has an opening area proportion of at most 45% of a total area of ​​the basket side wall

[0048] 8a. In more specific implementations, the opening area portion amounts to a maximum of 30% of the total area of ​​the basket side wall 8a. In even more specific, preferred implementations, the opening area portion amounts to a maximum of approximately 10% of the total area of ​​the basket side wall 8a. Conversely, this means that the area or material portion of the plate material of the basket side wall 11a, relative to the total extent of the basket side wall 11a, in these implementations of the electrode plate 2, 3 is at least 65% or at least 70%, or preferably at least 90%.

[0049] In advantageous embodiments, the opening structure 11 has at least one axial slot opening 12, which extends with a main directional component in a basket axial direction KA. A corresponding exemplary embodiment is shown in Figs. 4 and 5. Specifically, in this example, the respective current transmitter basket 8 contains a plurality of axial slot openings 12, e.g., eight slot openings 12, each extending purely in the axial / radial direction without a circumferential direction component. Furthermore, in this example, the respective axial slot opening 12 extends continuously from the plateau surface 9, which forms the base of the current transmitter basket 8, to the edge 10 of the current transmission region 6a or of the current transmitter basket 9.

[0050] In advantageous embodiments, the opening structure 11 has at least one transverse slot opening 13 which extends with a main directional component in a basket circumferential direction Ku. The exemplary embodiment of Figs. 1 to 3 is such an embodiment, wherein the opening structure 12 in this case has a plurality of such transverse slot openings 13. Specifically, the slot openings 13 in this example are arranged purely in the circumferential direction Ku without any component in the axial or radial direction on two different radii between the plateau surface 9, which forms the base of the current transmitter basket 8, and the edge 10, preferably approximately centrally offset from one another in the circumferential direction on the two radii, as shown.

[0051] While in the embodiments of Figs. 1 to 5 the basket side wall 8a has no other openings except for the axial or transverse slot openings 12, 13, Fig. 6 shows an embodiment in which the opening structure 11 of the basket side wall 8a includes several of the transverse slot openings 13 and additionally a plurality of substantially circular to slightly oval hole openings 14. The hole openings 14 can, for example, be those of a hole pattern 15 with which the plate body 6 is provided in its preferably planar plate main part 6b outside the current transmission region 6a and thus the current transmitter baskets 8, as shown in Figs. 2 and 4 for the electrode plate 2 there.In alternative embodiments not shown, the opening structure can include any combination of differently shaped, entirely or predominantly axially extending or entirely or predominantly transversely extending slots and / or circular or slightly oval hole openings.

[0052] In corresponding embodiments of the electrode plate 2, 3, the opening structure 11 has at least one flap opening 16, which is formed by slitting and bending a corresponding plate body region within the current transmission region 6a of the plate body 6 and whose basic shape can be seen in Fig. 7. Optionally, the plate body 6 can additionally or alternatively be provided in its main plate part 6b outside the current transmission region 6a with one or more such flap openings 16, in particular also with a corresponding flap opening pattern consisting of a plurality of such flap openings 16 arranged regularly across the plate body 6. In alternative embodiments, one or more such flap openings 16 can also be provided only in the region of the plate body 6 outside the current transmission region 8.

[0053] Fig. 7 illustrates an embodiment in which several such flap openings 16 are introduced into the main plate part 6b of the electrode plate 2, 3, wherein, as required, one or more of these flap openings 16 can also be provided only in the current transmission region 6a or only in the main plate part 6b or in both regions 6a, 6b of the plate body 6. As can be seen therefrom, the respective flap opening 16 contains an elongated hole-shaped opening region 16a, which is formed by a slit of appropriate shape and length being introduced into the plate material and then a strip-shaped region of the plate material on one side of the slit being pushed backwards by mechanical deformation, e.g. deep drawing, to form a corresponding flap part 16b. In the example shown, a straight slit is introduced into the plate material and the flap part 16b is pocket-shaped in such a way that the flap opening 16 orthe opening area 16a, which is elongated in cross-section, has a curved course with an arc angle of approximately 90°, in that it extends from a plane in the plate E. P lying inlet area to an outlet area which is in a plane to the plate E P essentially vertical plane. In an alternative embodiment, the slot can be U-shaped in the plate material, and the area of ​​the plate material surrounded by it is approximately vertically backwards from the plate plane E P formed so as to protrude, while at the front of the plate body 6, the edge of the flap opening 16 is thereby preferably slightly rounded. In this case, the flap opening 16 extends straight through the plate body 6.

[0054] The flap openings 16 formed in one way or another can facilitate the discharge of gases to the rear side of the electrode plate 2, 3. This principle of the flap openings 16 can also be easily applied to the deep-drawn structure of the basket side wall 8a of the current transmitter basket 8, if required, i.e., the flap openings 16 can be formed in the basket side wall 8a by a deep-drawing process, e.g., together with the formation of the basket side wall 8a projecting from the plate body 6. The formation or longitudinal direction of the flap openings 16 then preferably runs in the basket circumferential direction K. u , e.g. in an arrangement on several radii comparable to the arrangement of the aforementioned transverse slot openings 13.

[0055] In advantageous embodiments, the respective current transformer basket 8 has a basket diameter K at its edge 10 D of a maximum of 60mm. In more special designs, the basket diameter KD maximum 40mm, ie approx. 40mm or less, e.g. approx. 30mm to 35mm.

[0056] In advantageous embodiments, the current transformer basket 8 is a deep-drawn structure, ie it is formed in the current transmission area 8 of the plate body 6 by a conventional deep-drawing forming process from the plane E Pof the plate body 6, i.e., from the main plate part 6b. In this case, the electrode plate 2, 3 can be manufactured with relatively little effort from a plate blank, into which the current transmitter basket(s) 8 are formed or stamped by deep drawing, wherein, if necessary, the slots or recesses required for the optional opening structure 11 are first introduced into the current transmission area 6a of the plate blank, from which the plate body 6 of the electrode plate 2, 3 is then formed. The deep drawing process can, as usual, involve the use of suitable positive / negative molds, which specify the desired basket / cup contour for the current transmitter basket 8.

[0057] In advantageous embodiments of the electrode packing unit, at least one plateau surface 9 of the first current transfer structure 4 is arranged on the bipolar plate 1 so as to overlap a plateau surface 9 of the second current transfer structure 5, wherein in the present case this is understood to mean an overlap with respect to the direction perpendicular to the plane of the bipolar plate 1 and thus also of the main plate part 6b. This is how it is realized in the embodiment of Fig. 1, wherein preferably all plateau surfaces 9 of the first current transfer structure 4 each overlap with one of the plateau surfaces 9 of the second current transfer structure 5. In the embodiment shown, the overlap is complete, ie the plateau surfaces 9 are flush with each other on both sides of the bipolar plate 1, as can be seen from Fig. 1.

[0058] In alternative, not-shown embodiments of the electrode packing unit, at least one plateau surface 9 of the first current transfer structure 4 is arranged on the bipolar plate 1, offset from the plateau surfaces 9 of the second current transfer structure 5. In further alternative, not-shown embodiments of the electrode packing unit, at least one plateau surface 9 of the second current transfer structure 5 is arranged on the bipolar plate, offset from the plateau surfaces 9 of the first current transfer structure 4. In the electrode packing unit, the electrode plates 2, 3 are electrically conductively and mechanically firmly connected to the bipolar plate 1 via the plateau surfaces 9, e.g., by welding.Due to the compressive stiffness of the basket side walls 8a of the current transfer baskets 8, a pressure-stable composite of bipolar plate 1 and electrode plates 2, 3 is obtained for the electrode packing unit, which can withstand any weight-related pressure loads as well as any operational pressure loads.

[0059] This has the advantage that the cell frames in which the stacked electrode packing units of a block or stack are held do not have to be designed to absorb these axial compressive loads, so that flexible plastic materials, for example, can be used to realize the cell frames, which is advantageous for many applications. To give an example, in a typical embodiment, a stack can be constructed from 100 to 140 electrode packing units, each weighing approximately 4 to 7 kg. Due to the correspondingly pressure-resistant current transmitter baskets 8, the electrode packing units according to the invention are able to absorb the resulting weight loads, even if the electrode packing units are oriented horizontally in the stack.

[0060] Advantageously, in the electrode packing unit according to the invention, it is possible, as can be seen in Fig. 1, to determine a distance A1 of the plate main part 6b of the first electrode plate 2 from the bipolar plate 1 by the distance of the one or more plateau surfaces 9 of the first current transfer structure 4 from the plate main part 6b, ie from the plane E P of the plate body 6 of the first electrode plate 2, ie by the basket height KH of the current transformer baskets 8 of the integrated current transformer structure 7 of the first electrode plate 2.

[0061] Additionally or alternatively, a distance A2 of the plate main part 6b of the second electrode plate 3 from the bipolar plate 1 can be determined by the distance of the one or more plateau surfaces 9 of the second current transfer structure 5 from the plate main part 6b, ie from the plane E Pof the plate body 6 of the second electrode plate 3, i.e., by the cage height KH of the current transformer cages 8 of the integrated current transformer structure 7 of the second electrode plate 3. In particular, it is possible to set the distances A1, A2 of the plate main part 6b of the first electrode plate 2 or of the plate main part 6b of the second electrode plate 3 from the bipolar plate 1 independently of one another, i.e., the two distances A1, A2 can be specified to be the same or different.

[0062] As the embodiments shown and the further embodiments described above make clear, the invention provides an electrode plate which is comparatively easy to produce and has significant functional advantages, in particular with regard to the integration of the current transfer structure, pressure stability of the current transfer structure, provision of a large effective electrode area for a given overall dimension of the electrode plate and permeability of the electrode plate for the required gas / liquid transport.

[0063] Furthermore, the invention provides an electrode packing unit advantageously constructed with one or more such electrode plates, which can be constructed with relatively little effort and from which a desired stack or block or stack for a corresponding electrochemical reactor can be constructed with relatively little effort, such as an electrolysis reactor for the electrolysis of water under pressure or without pressure, or a fuel cell reactor.

Claims

Claims 1. Electrode plate for a stacked structure of an electrochemical reactor, in particular an electrolysis reactor or a fuel cell reactor, comprising: - a plate body (6) and - an integrated current transfer structure (7), which is an integral part of the plate body and consists of at least one current transfer body, which is formed in a current transfer area (6a) of the plate body projecting from a plate main part (6b) of the plate body and includes a plate surface (9) spaced apart from the plate main part (6b) and designed for contact with a bipolar plate of the stacked structure, and a connection structure connecting the plate surface to an edge (10) of the current transfer area, characterized in that: - the current transfer body is a current transfer basket (8) formed from a formed area of ​​the plate body with a pressure-resistant and electrically conductive basket side wall (8a),which forms the connection structure.

2. Electrode plate according to claim 1, further characterized in that the basket side wall has an opening structure (11).

3. Electrode plate according to claim 2, further characterized in that the opening structure has an opening area fraction of at most 45% or at most 30% or at most 10% of a total area of ​​the basket side wall.

4. Electrode plate according to claim 2 or 3, further characterized in that the opening structure has at least one axial slot opening (12) which is oriented with a principal directional component in the basket axial direction (K, A ) extends.

5. Electrode plate according to one of claims 2 to 4, further characterized in that the opening structure has at least one transverse slot opening. (13) having a principal directional component extending in the basket circumferential direction (Ku).

6. Electrode plate according to any one of claims 2 to 5, further characterized in that the opening structure has at least one flap opening (14) formed by slitting and one-sided bending of a corresponding plate body area.

7. Electrode plate according to any one of claims 1 to 6, further characterized in that the current transformer basket has a basket diameter (K) at its edge. D) of at most 60 mm or at most 40 mm.

8. Electrode plate according to one of claims 1 to 7, further characterized in that the current transfer basket is a deep-drawn structure.

9. Electrode packing unit for a stacked structure of an electrochemical reactor, in particular an electrolysis reactor or a fuel cell reactor, comprising: - a fluid-tight bipolar plate (1), - a first electrode plate (2) and a second electrode plate (3) arranged on opposite sides of the bipolar plate, and a first current transfer structure (4) for electrically and mechanically connecting the bipolar plate to the first electrode plate, and a second current transfer structure (5) for electrically and mechanically connecting the bipolar plate to the second electrode plate, characterized in thatthat - the first electrode plate (2) is one according to any one of claims 1 to 8 and the first current transformer structure (4) is formed by the integrated current transformer structure (7) of the first electrode plate and / or - the second electrode plate (3) is one according to any one of claims 1 to 8 and the second current transformer structure (5) is formed by the integrated current transformer structure (7) of the second electrode plate.

10. Electrode packing unit according to claim 9, further characterized in that at least one plateau surface of the first current transfer structure is arranged on the bipolar plate overlapping with a plateau surface of the second current transfer structure.

11. Electrode packing unit according to claim 9 or 10, further characterized in that at least one plateau surface of the first current transfer structure is arranged on the bipolar plate offset from the plateau surfaces of the second current transfer structure and / or at least one plateau surface of the second current transfer structure is arranged on the bipolar plate offset from the plateau surfaces of the first current transfer structure. 12.Electrode packing unit according to one of claims 9 to 11, further characterized in that a distance (A1) of a plate main part of the first electrode plate from the bipolar plate can be determined by a distance of the plateau surfaces of the first current transfer structure from the plane of the plate body of the first electrode plate and / or a distance (A2) of a plate main part of the second electrode plate from the bipolar plate can be determined by a distance of the plateau surfaces of the second current transfer structure from the plane of the plate body of the second electrode plate.

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