Cell component arrangement for an electrochemical system

Abstract

The invention relates to a cell component arrangement (1) for an electrochemical system, comprising a three-dimensionally structured plate element (16) which separates different flow spaces from one another, is arranged between a first frame (4) and a second frame (38) and forms an embossing field (12) which is connected to a port (5, 5') of the electrochemical system in each case via a plurality of passage regions (7) which are parallel to one another and define a flow direction (FR).

Description

[0001] Electrolyzer and cell component arrangement for an electrochemical system

[0002] The invention relates to an arrangement of cell components intended for use in an electrochemical system. Furthermore, the invention relates to an electrolyzer, in particular for the production of hydrogen from water.

[0003] WO 2022 / 184199 A1 discloses an electrolysis plate for hydrogen production and a method for manufacturing an electrolysis plate. The electrolysis plate comprises at least one embossed sheet, which is designed to delimit a flow channel and has individual, droplet-shaped embossed elements.

[0004] Another electrolysis plate, designed for use in a hydrogen production plant, is described in WO 2022 / 171237 A1. Embossed patterns are formed on a profiled sheet of this electrolysis plate, arranged at least three times in succession, without overlapping or touching.

[0005] EP 3 396 025 B1 relates to a continuous manufacturing technique for producing a non-reinforced electrochemical cell component. The manufacturing process involves forming a web shape from a web material suspension directly on the surface of a conveyor belt.

[0006] WO 2023 / 020 647 A1 describes a bipolar plate comprising two embossed and interconnected half-sheets.

[0007] German patent DE 10 2004 016 318 A1 discloses a bipolar plate for electrochemical systems and a method for its manufacture. The bipolar plate comprises two plates joined together, which are provided with raised areas and / or channel structures by means of roll embossing, stamping, hydroforming or eddy current embossing.

[0008] DE 10 2022 104 250 A1 describes a thin sheet and a method for rolling a thin sheet for an electrochemical cell.

[0009] DE 699 05 177 T2 discloses an electrochemical reactor in the form of a redox flow battery.

[0010] DE 10 2018 220 464 A1 discloses a distributor structure designed for use in a fuel cell or electrolyzer. It is proposed that the distributor structure be formed by a plastic component with electrically conductive properties. The distributor structure provides a channel structure, which can be configured as an insert held by a partition plate. The channel structure described in DE 10 2018 220 464 A1 can include small droplet-shaped contact points that contact a polymer membrane. The design of the channel structure is intended to have a positive effect on the discharge of process water.

[0011] DE 100 15 360 A1 discloses a separator unit for electrolysis cells and fuel cells made of two embossed plates.

[0012] From DE 10 2022 106 374 A1, a bipolar plate intended for use in a fuel cell stack and a method for manufacturing a bipolar plate are known. This bipolar plate has a folded area adjacent to a port in which flow channels for a cooling medium are formed.

[0013] US Patent 6,410,179 B1 describes a bridge-shaped insert for a fluid flow plate of a fuel cell, which can be inserted at the transition between a distributor opening in the plate and an area structured with coiled fluid channels.

[0014] The invention is based on the objective of further developing the manufacture of components of electrochemical systems, in particular electrolysis systems, compared to the prior art, taking into account manufacturing aspects as well as fluid dynamics aspects and static requirements.

[0015] This problem is solved according to the invention by a cell component arrangement for use in an electrochemical system according to claim 1. In particular, the cell component arrangement can be attributed to an electrolyzer according to claim 20.

[0016] The cell component arrangement according to claim 1 comprises a three-dimensionally structured plate element, separated from different flow spaces and arranged between a first frame and a second frame, through which an embossing field is formed. This embossing field is connected to a port of the electrochemical system via several mutually parallel passageways that define a flow direction. The sum of the passageways arranged on the same side of the embossing field is less than the width of the embossing field supplied by these passageways.Within the embossing field, adjacent to each flow path, at least two embossing guide elements are formed in both the inlet and outlet sections of the embossing field. These elements, when combined, form a fan-shaped profile suitable for splitting or merging the flowing medium, depending on the flow direction. In the flow direction between the inlet and outlet sections, the embossing field consists of a multitude of embossing elements. These are primarily elongated embossing elements arranged in rows, parallel to each other and aligned in the flow direction. The embossing guide elements can, for example, be curved and mirrored to the central axis of the flow path. Alternatively, the individual embossing guide elements can be straight. A combination of straight and curved embossing guide elements is also possible.

[0017] The sum of the passage areas arranged on one and the same side of the embossing field is, in particular, less than half the width of the embossing field supplied by these passage areas and subjected to flowing medium.

[0018] The flow-through areas can be configured to direct coolant into or away from an area associated with or adjacent to an active field. An active field is defined as an area of ​​an electrochemical cell in which electrochemical reactions take place at a membrane. The active field of each electrochemical cell, viewed from above the plate-shaped structures of the electrochemical system, is located within the embossing field. The flow-through areas do not serve to distribute the coolant transversely to the main direction in which the coolant flows towards or away from the active field. Rather, this function is performed by structures within the embossing field in this configuration.

[0019] The aforementioned frames can differ from one another with respect to their clear width, that is, the extent of their central opening. The first frame is located on one side of the plate element structured in the form of the embossing field, which faces an additional, flat plate element, and the second frame is located on the opposite side of the plate element structured in the form of the embossing field, which is specifically arranged facing an electrochemical cell. There are not necessarily differences between the various frames with respect to their external dimensions. This also applies to embodiments in which a seal is located on each frame, with an overlap between the seals when viewed from above.

[0020] Regardless of the presence of a second, flat plate element and a plurality of different frames, the cell component arrangement according to the invention, according to various possible embodiments, comprises a three-dimensionally structured plate element separating different flow spaces from one another. This plate element forms an imprinting field, which is connected to a port of the electrochemical system, in particular an electrolysis system, via a flow-direction-defining passage area. The structuring of the plate element allows for the formation of various groups of three elongated, adjacent imprinting elements aligned longitudinally, i.e., in the flow direction, of the passage area.This consists of a central group of three embossing elements located in a straight line extending from the passage area, and two outer groups of three embossing elements arranged laterally to the central group of three, mirror images of the central axis of the passage area. In particular, each of the groups of three embossing elements is a mirror image of itself with respect to a mirror plane passing centrally through the middle of the three embossing elements belonging to the same group of three.

[0021] In each of the various groups of three embossing elements, the middle embossing element can be located closer to the edge of the embossing field bordering the through-flow area than the two lateral embossing elements located next to the middle embossing element. At the same time, each of the two outer groups can be located closer to the edge of the embossing field than the middle group of three embossing elements.

[0022] Overall, this creates a system of repeating symmetry, which is adapted to the flow conditions at the transition between the through-flow area and an active field of the electrochemical system limited by the structured plate element. In particular, the two outer groups of three embossing elements can extend to the edge of the embossing field.

[0023] Depending on various possible configurations, several of the aforementioned embossing guide elements belonging to the embossing field can be arranged between the central group of three and the flow area. This applies, among other things, to cases in which two embossing guide elements with a straight or curved shape are mirror images of the central axis of the flow area. Regardless of any radius of curvature, the embossing guide elements each have a first end facing the flow area and a second end facing one of the two outer groups of three. Optionally, there are also two embossing elements that are straight, oriented transversely to the flow direction (i.e., the central axis of the flow area), parallel to the edge of the embossing field and thus orthogonal to the flow direction in the flow area, and each arranged between one of the curved embossing guide elements and one of the two outer groups of three.

[0024] Regardless of the design of the areas between the central and the two outer groups of three embossing elements, several rows of elongated embossing elements arranged orthogonally to the central axis of the flow area can be present on the side of the groups of three elements facing away from the flow area. The longitudinal axis of each elongated embossing element is aligned parallel to the central axis of the flow area. The elongated embossing elements, arranged in parallel rows, contribute significantly to the homogenization of the flow directed by the structuring of the embossing field, after it has been widened by the group of three embossing elements and the optional additional embossing elements. The same applies to the collection of fluid to be fed into a flow area.The plate element exhibiting three-dimensional structuring, like the flat plate element, can in particular be classified as a bipolar plate of the electrochemical system, wherein the respective plate element separates a coolant chamber from a service material chamber of the electrochemical system. In particular, the structured plate element is designed as a half-sheet of a bipolar plate, wherein the two half-sheets of the bipolar plate are not necessarily mirror-symmetrical to each other.

[0025] The embossed area of ​​the structured plate element, for example, has a rectangular shape and generally a total area GA. It may have an end face SF, intended in particular for contacting an open-porous transport layer of an electrochemical cell of the electrochemical system. Furthermore, the embossed area may have a smooth surface GF spaced parallel to and spaced from a plane adjacent to the aforementioned end face, with the following relationship:

[0026] 0.5 < (SF x GA) Z GF 2 < 1

[0027] For example, the dimensionless fraction whose numerator is the product of the end face SF and the total area GA, and whose denominator is the smooth surface GF squared, lies in the range of 0.55 to 0.75, in particular at about 2 / 3.

[0028] The port, from which fluid, particularly a coolant, is directed via the through-flow area to the stamping field, or into which fluid flows that is discharged from the stamping field via the through-flow area, has, for example, a circular or square cross-sectional shape. Other cross-sectional shapes of the port are also possible. In particular, it has proven advantageous if the port, viewed from above the stamping field and the adjacent through-flow area of ​​the electrochemical system, widens with increasing distance from the stamping field. This can be the case, for example, with a trapezoidal cross-section of the port. The same can apply to ports that describe a roof or triangular shape in cross-section.

[0029] In each of these cases, a port for conveying operating fluids of the electrochemical system can be arranged between two such adjacent ports for the passage of coolant. This latter port tapers with increasing distance from the embossing field and is, overall, closer to the embossing field than the coolant ports. The port through which an operating fluid, i.e., a starting or end product of an electrochemical reaction, flows during operation of the electrochemical system can also have a roof or triangular shape, but this shape is inverted compared to the coolant port.The alternating arrangement of ports, i.e., openings, with a roof shape and an inverted roof shape, allows for a large portion of the available area to be used for media passage and achieves a good balance between material usage and stability. In particular, the structures, reminiscent of roofs or small houses and essentially comparable to the described structures of the embossing field, can be manufactured through material forming, especially sheet metal forming.

[0030] It has proven effective to arrange two mutually aligned coolant flow areas between two supply areas.

[0031] In particular, in each coolant passage area, a strip-shaped insert, through which coolant can flow along its length, is inserted or used, by which the respective passage areas are divided into at least two parallel sub-channels.

[0032] Each insert preferably also forms a support against an adjacent flat plate element, which, in addition to the structured plate element, can also be attributed to a bipolar plate of the electrochemical system.

[0033] An electrochemical system in the form of an electrolyzer, particularly for the electrolysis of water into hydrogen and oxygen, has proven especially effective. It comprises at least one electrochemical cell with at least one cell component arrangement designed according to the invention, wherein the following are present in this sequence: the flat plate element, the first frame, the structured plate element with or without inserts, the second frame, at least one first open-porous transport layer, a membrane, and at least one second open-porous transport layer. Adjacent to the second open-porous transport layer, this sequence is repeated starting with another flat plate element.

[0034] The first frame surrounds the embossed area of ​​the structured plate element, thus enabling the cooling of the electrochemical cell located on the opposite side of the structured plate element within the active field. The first frame and the raised areas of the embossed field protruding through the opening in the first frame are essentially flush and form a contact surface for an adjacent flat plate element. They are essentially flush because a slight difference in the nominal dimension may be acceptable due to tolerances. Together, the structured plate element, particularly made of metal, and the flat plate element, particularly made of metal, form a bipolar plate, although they are not physically bonded together but merely pressed against each other.In the free space between the flat plate element and the structured plate element there is an area through which coolant, in particular cooling water, can flow.

[0035] The second frame seals the structured plate element against the membrane and encompasses at least one first open-porous transport layer around its circumference. An open-porous transport layer is preferably formed from an open-porous sintered body, for example, made of titanium or a titanium alloy, and is preferably coated on its side facing the membrane or membrane-electrode unit. Alternatively or additionally, an open-porous transport layer can also be formed from a layer of expanded metal, a metal mesh, or the like.

[0036] The membrane is preferably a polymer electrolyte membrane, which can also be designed as a membrane electrode assembly known per se, i.e., coated on both sides with electrode material in an electrically conductive and / or catalytically active manner.

[0037] Several embodiments of the invention are explained in more detail below with reference to the drawings. These show:

[0038] Fig. 1 Components of an electrochemical system, namely an electrolyzer, in top view,

[0039] Fig. 2 shows a section of a cell component arrangement of the electrochemical system according to Fig. 1 in a sectional view.

[0040] Fig. 3 shows a detail of the cell component arrangement of the electrochemical system according to Figures 1 and 2.

[0041] Fig. 4 shows a modified cell component arrangement in a view analogous to Fig. 3.

[0042] Fig. 5 shows an enlarged section of an embossing field of a plate element of the arrangement according to Fig. 1 ,

[0043] Fig. 6 shows a detail of the structured plate element according to Fig. 5 in a sectional view.

[0044] Fig. 7 shows the embossing field according to Fig. 5 in a further illustration,

[0045] Fig. 8 shows the entire embossing field according to Fig. 5 in top view,

[0046] Fig. 9 shows a detail of the embossing field according to Figures 5 to 8, Fig. 10 shows the embossing field in a modified representation compared to Fig. 9.

[0047] Fig. 11 shows the second frame in a top view,

[0048] Fig. 12 shows a section AA according to Fig. 11 in perspective view,

[0049] Fig. 13 shows a detail B of the arrangement according to Fig. 12 in a sectional view,

[0050] Fig. 14 Components of a stack of electrochemical cells in top view,

[0051] Fig. 15 shows a detail of the arrangement according to Fig. 14 in a sectional view,

[0052] Fig. 16 shows a section of an electrode plate of the cell stack according to Fig. 14,

[0053] Fig. 17 shows a section of the plate arrangement according to Fig. 14 in a view analogous to Fig. 16,

[0054] Fig. 18 shows an insert used as a component of the arrangement according to Figures 14 and 17 in a perspective view,

[0055] Fig. 19 shows the installation situation of the insert according to Fig. 18 in a sectional view.

[0056] Fig. 20 shows a modified embodiment of an insert in a perspective view,

[0057] Fig. 21 shows an insert designed as a sheet metal part for a stack of electrochemical cells,

[0058] Fig. 22 shows the installation situation of the insert according to Fig. 21 in a sectional view.

[0059] Fig. 23 shows another embodiment of an insert for a cell stack in a representation analogous to Fig. 20.

[0060] Fig. 24 shows the installation situation of the insert according to Fig. 23 in a sectional view.

[0061] Fig. 25 shows a section of the plate arrangement, which includes the insert according to Figures 23 and 24, in a view analogous to Fig. 17, and

[0062] Fig. 26 shows a partial view of a plate arrangement, including a detail of an insert modified compared to the arrangement in Fig. 25. Unless otherwise stated, the following explanations refer to all embodiments. Corresponding or essentially equivalent parts are marked with the same reference numerals in all figures.

[0063] A cell component arrangement 1 is intended for use in a stack of electrochemical cells, designated as 10 in general, in the present case an electrolysis cell stack. Regarding the basic structure of the cell stack 10, also referred to as the stack, reference is made to the above explanations and the prior art cited at the beginning. The stack 10 is the core component of an electrolyzer 20 for producing hydrogen from water. Within the stack 10, the process water, i.e., water that is split into hydrogen and oxygen, is separated from the coolant circuit, preferably the cooling water circuit. This implies that the composition of the cooling medium, referred to generally as cooling water, can differ from the process water, with the process water typically having a higher degree of purity. Depending on the operating and ambient conditions, the coolant can also be used to heat the stack 10.

[0064] Active fields 2 are formed by numerous electrochemical cells 11, i.e., electrolysis cells, stacked one above the other in the stack 10. In the embodiment shown in Figures 1, 8, and 14, these active fields have an approximately rectangular plan, corresponding roughly to the opening 2' in the second frame 38 (see Figure 11). Hydrogen is produced in the electrochemical cells 11 using electrical energy in a manner known per se. A first frame, which has an opening for the embossing field 12, is designated 4. A second frame, designated 38, has a larger clear opening than the first frame 4, as can be seen in Figure 2. A seal 3, 3a is formed on each frame 4, 38, on the side facing the interior of the stack 10. Between the first frame 4 and the second frame 38 is the structured plate element 16 with its embossing field 12, which is visible through the opening of the first frame 4 according to Figure 1.The first frame 4 and the raised areas of the embossing field 12 projecting through the opening in the first frame 4 are essentially at the same height and form a contact surface for the adjacent flat plate element 17, see Figure 2. Together, the structured plate element 16, in particular made of metal, and the flat plate element 17, in particular made of metal, form a bipolar plate, although they are not bonded together but merely pressed against each other. The free space between the flat plate element 17 and the structured plate element 16 contains a region through which coolant, in particular cooling water, can flow.

[0065] The second frame 38 seals the structured plate element 16 against the membrane 13 and encompasses the circumference of at least one first open-porous transport layer 14', here composed of two layers. Furthermore, the second frame 38 also seals the circumference of at least one second porous transport layer 14', here composed of two layers.

[0066] The second frame 38 has a step S that lowers the edge of the frame 38 to the level of at least one second porous transport layer 14, with the seal 3a extending over the step S and thus continuing to form a seal between the structured plate element 16 and another flat plate element 17' through the second frame 38. The second frame 38 therefore seals an electrochemical cell 11 at the perimeter of the respective active field 2, which is arranged below the embossing field 12 on the back side of the structured plate element 16 according to Figure 1, via the second seal 3a.

[0067] For the supply and discharge of coolant, six coolant ports 5, 5' are provided in each of the exemplary embodiments. A plurality of stacked coolant ports 5, 5' are each assigned to a main channel, which runs orthogonally to the planes in which the active fields 2 are located. The same applies to main channels through which operating media of the cell stack 10 flow. Operating ports 6 for the supply of process water and operating ports 6' for the discharge of process water including oxygen are assigned to the latter main channels. Furthermore, outlets H2 are provided for the discharge of hydrogen and, if necessary, additional process water. As can be seen from Figures 1 and 14, two groups of seven ports 5, 6; 5', 6' are positioned opposite each other in a mirror-symmetrical arrangement on the longitudinal sides of the embossing field 12. Here, the coolant ports 5, 5' are further away from the longitudinal side of the embossing field 12 than the operating medium ports 6, 6'.In the arrangement according to Fig. 1, an inlet area located at the top is designated 39, and an outlet area is designated 40.

[0068] In contrast to the operating fluids, the coolant is not introduced into the electrochemical cells 11. Instead, the coolant flows between the three-dimensionally structured plate element 16 and the flat plate element 17, with the plate elements 16 and 17 together forming the bipolar plate. The second frame 38 is located on the side of the structured plate element 16 that faces the at least one open-porous transport layer 14'. The second frame 38 encompasses the at least one open-porous transport layer 14'. With respect to the arrangement according to Fig. 2, the first frame 4 is located essentially at the same height as the maximum deflection of an embossing field 12 of the structured plate element 16 and encompasses the embossing field 12, see Fig. 1.

[0069] The plate elements 16, 17 are preferably made of an electrically conductive material, with a metal being preferred. A steel sheet is particularly preferred.

[0070] The structured plate element 16 thus provides an embossing field 12, which on the one hand ensures turbulence and flow guidance of the coolant inside the bipolar plate and on the other hand also forms a flow-guiding structure on the outer surfaces of the bipolar plate, i.e., at the boundaries of the adjacent electrochemical cells 11. The width of the embossing field 12 is labelled B12 in Figure 8.

[0071] From ports 5, the coolant is guided via flow-through areas 7 into the cavity between the plate elements 16, 17 to uniformly cool the active fields 2 arranged above and below. Similarly, coolant flows out via similarly shaped flow-through areas 7 and ports 5'. B7 denotes the width of a flow-through area 7. The sum of the widths B7 of all flow-through areas 7 bordering the inlet area 39 is less than half the width B12 of the entire embossed area 12. The same applies to the flow-through areas 7 on the outlet side, i.e., the three flow-through areas 7 connected to the outlet area 40. In the exemplary embodiments, all flow-through areas 7 have a uniform width B7. Flow-through areas for operating fluids, designated 8, are significantly shorter than the flow-through areas 7 for coolant connected to the coolant ports 5, 5'.

[0072] With the exception of those located at the four corners of the active field 2, the operating port 6, 6' each describe the shape of a small house, which is set back somewhat from the edge of the embossed field 12 designated 28. This means that the cross-section of each operating port 6, 6' narrows with increasing distance from the edge of the embossed field 28 (see Figure 3). In contrast, the cross-section of each coolant port 5, 5' widens with increasing distance from the edge of the embossed field 28. The small house shape of the coolant ports 5, 5' is particularly evident in the view shown in Figure 11 of the second frame 38, corresponding to the opening 2' at the edge of the active field 2. The flanks of the coolant ports 5, 5' which are inclined opposite the embossing field edge 28 are designated by 18, as shown by way of example in Fig. 4.The flanks of the equipment ports 6, 6' are designated 19 and in all embodiments are aligned parallel to the flanks 18, so that webs are formed between the different ports 5, 6; 5', 6'.

[0073] The through-flow area 7, which connects each coolant port 5 with the embossing field 12, has a central axis MD that specifies the flow direction FR of the coolant.

[0074] In the embodiment according to Figures 1 and 3, embossing elements 30 are visible in the coolant passage areas 7, each having a short strip shape and being aligned in the longitudinal direction of the respective passage area 7.

[0075] In contrast, in the modified design according to Fig. 4, a strip-shaped insert 9 is inserted into each of the coolant passages 7, which has both a flow-guiding and a static function. The passage 7 is divided into several partial channels 15 by the strip-shaped insert 9, which is designed as a sheet metal part. The coolant flows through the insert 9 along its length. The two adjacent plate elements 16, 17, which belong to the same bipolar plate, are supported against each other in the cooling plane, among other things, by the inserts 9.

[0076] In all embodiments, the mechanically stable design of the plate elements 16, 17 contributes significantly to the stability of the entire cell stack 10 and also to maintaining the constant geometry of the individual electrochemical cells 11. The individual electrochemical cells 11 include, among other things, membranes 13, namely polymer electrolyte membranes, or membrane electrode units containing such membranes, as well as at least single-layer open-porous transport layers 14, 14'.

[0077] The embossing field 12 forms a structure 21 which includes various embossing elements 23, 24, 26, 27, 29, 31, 32, 33, 34, some of which are grouped in a defined manner into groups 22, 25, and which will be discussed below.

[0078] In a straight extension of the coolant passage area 7, a central group of three embossing elements 22, spaced from the edge of the embossing field 28, is located. The three embossing elements 23, 24 consist of a central embossing element 23 and two lateral embossing elements 24 (see also Figure 5). Each of the embossing elements 23, 24 has an elongated shape oriented in the flow direction FR, i.e., parallel to the central axis MD, with the central axis of the central embossing element 23 coinciding with the central axis MD. The group of three elements 22 is mirror-symmetrical about a mirror plane defined by the central axis MD. Of the three embossing elements 23, 24 forming the group of three 22, the central embossing element 23 is the closest to the edge of the embossing field 28.The two outer embossing elements 24 are shorter than the middle embossing element 23, with the latter embossing element 23 projecting beyond the outer embossing elements 24 in both directions along the central axis MD. A hexagon, indicated in Fig. 3, can thus be placed around the entire central group of three embossing elements 22, which is tangent to each of the embossing elements 23, 24, with the angles at the vertices of this hexagon being exclusively less than 180°.

[0079] The outer groups of three 25 are to be distinguished from the central group of three 22, which, viewed in the direction of flow FR, are located laterally next to the central group of three 22 and are closer to the embossing field edge 28. In the case of the outer groups of three 25, there is a central embossing element 26, which is flanked by two lateral embossing elements 27. The central embossing element 26, in principle comparable to the central group of three 22, has the shortest distance to the embossing field edge 28 and thus forms the apex of the symmetrical group 25. Unlike the central group of three 22, however, on the side of the group of three 25 opposite the apex, the central embossing element 26 is overshadowed by the two lateral embossing elements 27 in the longitudinal direction of the central axis MD. A hexagon circumscribing the lateral group of 3 25 thus has, as can be seen from Fig. 3, five angles less than 180° and one angle greater than 180° at its corners.

[0080] Upstream of the central group of three elements 22 in the flow direction FR are two curved embossing guide elements 29, which – like the central group of three elements 22 – are mirror-symmetrical about the central axis MD. Viewed from the passage area 7, the two embossing guide elements 29 describe a fork. Here, a first end of each embossing guide element 29 borders the embossing field edge 28, while the second end of the embossing guide element 29 points roughly towards one of the outer serif groups 25. Between the curved embossing guide element 29 and the outer group of three elements 25 on embossing elements 26, 27, a transversely oriented embossing element 31 is arranged, aligned parallel to and tangent to the embossing field edge 28. This embossing element 31, like the various embossing elements 23, 24, 26, 27, contributes to both the flow guidance and the mechanical stabilization of the three-dimensionally structured plate element 16.To a limited extent, this also applies to intermediate embossing elements 32, 33, namely a long intermediate embossing element 32 and a comparatively short intermediate embossing element 33, which - like the transversely placed embossing element 31 - are arranged in the space between the various groups of 3 22, 25.

[0081] In comparison to the sub-area of ​​embossing field 12 described above, which borders the edge of the embossing field 28, the sub-area of ​​embossing field 21, which is located further from the edge 28 of embossing field 12 and thus further from the through-passage area 7, is less complexly structured. Within the latter sub-area, several rows are...

[0082] 35 recognizable on elongated embossing elements 34, wherein the longitudinal axes of the individual embossing elements 34 are aligned parallel to the central axis MD, compare Figure 4.

[0083] Throughout the entire embossing area 12, a raised contact surface 36 is formed by the structuring 21, compare Figure 9, which is composed of numerous island-shaped sub-surfaces lying in a common plane. On the contact surface

[0084] 36 supports an adjacent flat plate element 17, compare Figure 2. In a base surface 37 parallel to the contact surface 36 there is undeformed material of the plate element 16, against which elements of the electrochemical cell 11, in particular the one or more layered open-porous transport layer 14', are supported.

[0085] The total area of ​​the multiply subdivided contact surface 36 formed by the embossing elements 23, 24, 26, 27, 29, 31, 32, 33, 34 is designated as the end surface SF. The area of ​​the base surface 37 is designated as the flat surface GF. The embossing field 12 covers a total area GA. The sum of the end surface SF and the flat surface GF is less than the total area GA, as can be clearly seen from a comparison of Figures 8 to 10. Furthermore, the following relationship applies in every embodiment, regardless of the units used:

[0086] 0.5 < (SF x GA) Z GF 2 < 1

[0087] Figures 11 to 13 show the second frame 38, which differs from the octagonal opening in the first frame 4 for the stamping area 12 with respect to the rectangular shape of the opening 2'. Figures 12 and 13, in particular, illustrate the aerodynamically optimized design of the edges, including the flanks 18, 19 of the ports 5, 6; 5', 6' located in the second frame 38. Figure 13 shows an example of a flank angle α, which indicates the inclination of a flank 19 relative to a surface normal of the base surface 37. The chamfered edges of the ports 5, 6; 5', 6' facilitate a low-resistance flow of the various fluids, i.e., operating fluid and coolant, between planes parallel to the base surface 37. At the same time, the edges of ports 5, 6; 5', 6', which are present among other things in the form of flanks 18, 19, have a mechanically stabilizing function within the cell stack 10.

[0088] As shown in Figure 14, two groups of seven ports 5, 6; 5', 6' are positioned opposite each other in a mirror-symmetrical arrangement on the longitudinal sides of the active field 2. The coolant ports 5, 5' are located further from the longitudinal side of the active field 2 than the operating medium ports 6, 6'. Unlike the operating medium, the coolant is not introduced into the electrochemical cells 11. Instead, the coolant flows between a structured plate element 16 and a flat plate element 17 (see Figure 2), which together form a bipolar plate. The embossed structure 12 ensures both turbulence and flow guidance of the coolant within the bipolar plate and also provides a flow-guiding structure on the outer surfaces of the bipolar plate, i.e., at the boundaries of the adjacent electrochemical cells 11.From ports 5, the coolant is directed via the passages 7 into the cavity between the plate elements 16, 17 to cool the entire active field 2 uniformly. Similarly, coolant flows out via similarly shaped passages 7 and ports 5'. The passages for operating materials at ports 6, 6', designated 8, are significantly shorter than the coolant passages 7 connected to ports 5, 5'.

[0089] Each of the coolant passages 7 contains a strip-shaped insert 9, which serves both a flow-guiding and a static function. The two adjacent plate elements 16, 17, belonging to the same bipolar plate, are supported against each other, among other things, by the inserts 9. The mechanically stable design of the bipolar plate contributes significantly to the stability of the entire cell stack 10 and also to maintaining the constant geometry of the individual electrochemical cells 11. The individual electrochemical cells 11 include, among other things, membranes 13, namely polymer electrolyte membranes, or membrane electrode units comprising a membrane 13, as well as the open-porous transport layers 14, 14'. Each coolant passage 7 is divided into several sub-channels 15 by the strip-shaped insert 9; in the exemplary embodiments, either three or six sub-channels 15.

[0090] The insert 9 is positively fixed between the plate elements 16, 17 in all cases. For this purpose, the plate elements 16 have two openings 60 near the coolant port 5, 5' into which studs 70, i.e., short pins, of the insert 9 engage. Only in the embodiment according to Figures 21 and 22 are tabs 260 present instead of studs 70, which engage in slot-shaped recesses in a plate element 16. In all other embodiments, a rib-shaped channel wall 90 adjoins each stud 70, separating parallel partial channels 15 from one another.

[0091] With the exception of the embodiment shown in Figures 21 and 22, the strip-shaped channel walls 90 diverge towards the active field 2 at the end of the sub-channels 15, forming an active-field-side widening 200. A port-side widening opposite the widening 200 is designated 220.

[0092] In the embodiment according to Figures 14 to 19, in addition to the strip-shaped channel walls 90, there are a total of four short support strips 80, which, like the strip-shaped channel walls 90, contact the plate element 17 and are integrally formed on a base plate of the insert 9 designated 230.

[0093] The embodiment according to Figure 20 differs from the embodiment according to Figures 14 to 19 by a modified shape of the base plate 230 and by the omission of the short support strips 80. The modified basic shape is expressed, among other things, in a concave active-field-side recess 210 of the base plate 230.

[0094] The insert 9 according to Figures 21 and 22 is designed as a sheet metal part. In this case, the insert 9 forms two strips 240, which are referred to as raised strips without loss of generality. Between the two raised strips 240 lies a recessed strip 250, which rests on the plate element 16. The two strips 240, on the other hand, contact the flat plate element 17, which is shown above in the view of Figure 22, so that the supporting effect of the insert 9 is also present in this case. Each of the strips 240, 250 forms a wall of the three partial channels 15. A modification of the insert 9, not shown, provides that it has a non-uniform wall thickness, which in turn influences its dynamic properties during operation of the cell stack 10, including contact forces acting on surrounding components.

[0095] The embodiment shown in Figures 23 to 25 differs from the embodiment shown in Figure 20 in that the rib-shaped channel walls 90 are formed not only on the top but also on the underside of the base plate 230. The terms "top" and "bottom" do not, in this case, indicate the actual installation position of the insert 9. In the case of Figures 23 to 25, the coolant passage 7 is divided into a total of six sub-channels 15 by means of the insert 9. Three sub-channels 15 are located in an upper channel section 270 and three further sub-channels 15 in a lower channel section 280. The lower rib-shaped channel walls are designated 290.

[0096] The insert 9 according to Figure 36 differs from the insert 9 according to Figure 23 in the design of the transition area between the partial channels 15 and the embossed structure 12, which delimits the active field 2. As can be seen from Figure 26, a short central active-field-side protrusion 300 is located on the base plate 230, centrally between the ends of the strip-shaped channel walls 90. In addition, there are two outer active-field-side protrusions 310, also molded onto the base plate 230, which are located laterally next to the arrangement of the two channel walls 90 visible in Figure 26. In addition to the two channel walls 90 visible in Figure 26 on the upper side of the base plate 230, there are, analogous to the embodiment according to Figures 23 to 25, two lower strip-shaped channel walls 90 covered by the base plate 230.Similarly, lower active field-side elevations 300, 310 are also present, whereby the designation as "lower" or "upper" structure is not to be understood as a prejudgment for the actual installation position of the insert 9.

[0097] List of reference signs

[0098] Cell component arrangement

[0099] Active field ' Opening first seal a second seal first frame

[0100] Coolant port, inlet side (coolant) ' Coolant port, outlet side (heated coolant)

[0101] Resource port, inlet side (process water) ' Resource port, outlet side (process water plus oxygen)

[0102] Coolant flow area

[0103] Transit area for operating resources

[0104] Insert 0 Cell stack, Stack 1 Electrochemical cell 2 Embossing field 3 Membrane 4, 14' open-porous transport layer 5 Partial channel 6 Plate element, structured 7 Plate element, flat 8 Flank of coolant port 9 Flank of operating medium port 0 Electrolyzer 1 Structuring 2 Group of 3, center 3 Middle embossing element of the middle group of 3 4 Lateral embossing element of the middle group of 3 5 Outer group of 3 6 Middle embossing element of the outer group of 3 27 Lateral embossing element of the outer group of 3

[0105] 28 Edge of the embossing area

[0106] 29 Embossing guide element, curved

[0107] 30 Embossing element in the passage area 7

[0108] 31 Embossing element, positioned transversely

[0109] 32 Intermediate embossing element, long

[0110] 33 Intermediate embossing element, short

[0111] 34 elongated embossing element

[0112] 35 row of embossing elements

[0113] 36 Contact surface, raised = end face SF

[0114] 37 Base area

[0115] 38 second frame

[0116] 39 Inlet area

[0117] 40 Outlet area

[0118] 60 Opening for securing the insert

[0119] 70 studs, cones

[0120] 80 support strip, short

[0121] 90 Channel wall, rib-shaped

[0122] 200 expansion, active field side

[0123] 210 concave recess, active field side

[0124] 220 expansion, port side

[0125] 230 Base plate of the insert 9

[0126] 240 raised strip of the insert 9

[0127] 250 recessed strip of the insert 9

[0128] 260 tab

[0129] 270 upper channel area

[0130] 280 lower channel area

[0131] 290 lower rib-shaped channel wall

[0132] 300 average active field-side survey

[0133] 310 outer active field-side elevation a flank angle B7 width of a transmission area B12 width of the embossing field

[0134] FR Flow direction

[0135] MD Central axis of the passage area 7

[0136] H2 outlet hydrogen

[0137] S level

Claims

Patent claims 1. Cell component arrangement (1) for an electrochemical system, comprising a three-dimensionally structured plate element (16) separating different flow spaces and arranged between a first frame (4) and a second frame (38), through which an imprinting field (12) is formed, which is connected via several mutually parallel passage areas (7) defining a flow direction (FR) to a port (5, 5') of the electrochemical system, wherein the sum of the passage areas (7) arranged on the same side of the imprinting field (12) is less than the width (B12) of the imprinting field (12) supplied by these passage areas (7), and wherein in the imprinting field (12), adjacent to each passage area (7), both in an inflow area (39) and in an outflow area (40) of the imprinting field (12),For each flow area (7) at least two embossing guide elements (29) are formed, which together describe a fanning shape suitable for splitting or combining the flowing medium, and wherein, in the direction of flow (FR) between the inflow area (39) and the outflow area (40), the embossing field (12) is in the form of a plurality of embossing elements (34).

2. Arrangement (1) according to claim 1, characterized in that the embossing elements (34) formed in the embossing field (12) between the inflow area (39) and the outflow area (40) are in the form of a plurality of elongated embossing elements (34) arranged in rows (35) parallel to each other and aligned in the flow direction (FR).

3. Arrangement (1) according to claim 1 or 2, characterized in that the embossing guide elements (29) are curved, mirror-image to the central axis (MD) Elements of the embossing field (12) formed in the passage area (7) are present.

4. Arrangement (1 ) according to one of claims 1 to 3, characterized in that the sum of the passage areas (7) arranged on one and the same side of the embossing field (12) is less than half of the width (B12) supplied via these passage areas (7) of the embossing field (12) to be supplied with flowing medium.

5. Arrangement (1) according to one of claims 1 to 4, characterized in that the passage areas (7) are designed to guide coolant for distribution or merging within an active field (2) formed in the area of ​​the embossing field (12).

6. Arrangement (1) according to one of claims 1 to 5, characterized in that the frames (4, 38) differ from each other with respect to their clear width, wherein the first frame (4) is located on one side of the plate element (16) structured in the form of the embossing field (12), which faces a flat plate element (17) and the second frame (38) is located on an opposite side of the plate element (16) structured in the form of the embossing field (12).

7. Arrangement (1 ) according to claim 6, characterized in that a seal (3, 3a) is located on each frame (4, 38), wherein - in top view of the plate elements (16, 17) - there is an overlap between the seals (3, 3a).

8. Arrangement (1) according to one of claims 1 to 7, characterized in that various groups of 3 (22, 25) are formed by structuring (21) the structured plate element (16) on elongated, adjacent embossing elements (23, 24, 26, 27) oriented in the longitudinal direction, i.e. flow direction (FR), of the passage area (7), namely - a middle group of 3 (22), which is located in a straight extension of the passage area (7), and - two outer groups of 3 (25) located laterally next to the middle group of 3 (22), arranged symmetrically to the central axis (MD) of the passage area (7), wherein in each of the different groups of 3 (22, 25) the respective middle embossing element (23, 26) is less distanced from the edge (28) of the embossing field (12) bordering the passage area (7) than the two lateral embossing elements (24, 27) located next to the respective embossing element (23, 26), and wherein each of the two outer groups of 3 (25) is less distanced from the edge (28) of the embossing field (12) than the middle group of 3 (22) of embossing elements (23, 24).

9. Arrangement (1 ) according to claim 8, characterized in that the two outer groups of 3 (25) extend to the edge (28) of the embossing field (12).

10. Arrangement (1) according to claim 3 in conjunction with one of claims 8 or 9, characterized in that the embossing guide elements (29) are arranged between the middle group of 3 (22) and the passage area (7) and each have a first end facing the passage area (7) and a second end facing one of the two outer groups of 3 (25).

11. Arrangement (1 ) according to claim 10, characterized by two embossing elements (31) positioned transversely to the flow direction (FR), aligned parallel to the edge (28) of the embossing field (12), each arranged between one of the curved embossing guide elements (29) and one of the two outer groups of 3 (25).

12. Arrangement (1) according to one of claims 8 to 11, characterized in that on the side of the 3- facing away from the passage area (7) Groups (22, 25) several rows (35) of elongated embossing elements (34) arranged orthogonally to the central axis (MD) of the passage area (7) are present, wherein the longitudinal axis of each elongated embossing element (34) is aligned parallel to the central axis (MD) of the passage area (7).

13. Arrangement (1 ) according to one of claims 6 or 7, characterized in that the structured plate element (16) and the adjacent flat plate element (17) are to be attributed to a bipolar plate of the electrochemical system, wherein the structured plate element (16) separates a coolant compartment from an operating medium compartment of the electrochemical system.

14. Arrangement (1) according to one of claims 1 to 13, characterized in that the embossing field (12) has a total area GA, an end surface SF, and a smooth surface GF spaced parallel to a plane which is applied to the end surface SF, wherein the following relationship applies: 0.5 < (SF x GA) Z GF 2 < 1 15. Arrangement (1 ) according to one of claims 1 to 14, characterized in that the port (5, 5') provided for the passage of coolant widens with increasing distance from the embossing field (12) in a top view of the embossing field (12) and the adjacent passage area (7).

16. Arrangement (1) according to claim 15, characterized in that between two adjacent ports (5; 5'), each of which is provided for the passage of coolant, a port (6; 6') for the passage of operating materials is arranged, wherein the latter port (6; 6') tapers with increasing distance from the embossing field (12) and has a smaller overall distance from the embossing field (12) than the ports (5; 5') to the coolant passage.

17. Arrangement (1 ) according to one of claims 1 to 16, characterized in that two mutually aligned flow areas (7) for coolant are each arranged between two flow areas (8) for operating resources.

18. Arrangement (1 ) according to one of claims 1 to 17, characterized in that in each passage area (7) for coolant a strip-shaped insert (9) is inserted, through which coolant can flow along its length, by which the respective passage areas (7) are divided into at least two parallel partial channels (15).

19. Arrangement (1 ) according to claim 18, characterized in that each insert (9) simultaneously forms a support against an adjacent planar plate element (17), which, in addition to the structured plate element (16), is also attributable to a bipolar plate of the electrochemical system.

20. Electrochemical system in the form of an electrolyzer (20), comprising at least one electrochemical cell (11) with at least one arrangement (1) of cell components designed according to one of claims 1 to 19, wherein the following are present in succession in this order: the flat plate element (17), the first frame (4), the structured plate element (16) with or without inserts (9), the second frame (38), at least one first open-porous transport layer (14), a membrane (13), at least one second open-porous transport layer (14'), wherein adjacent to the second open-porous transport layer (14') this sequence is repeated starting with a further flat plate element (17').

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