Cell layer for an electrochemical aggregate

Abstract

The invention relates to a cell layer (100) for an electrochemical cell stack (10, 60), in particular a fuel cell stack (10) or an electrolysis cell stack (60), at least comprising a cell frame (120) for the radial (Rr) fluid sealing of an electrochemically active region in the cell stack (10, 60), and a membrane (136) arranged within the cell frame (120) for an electrochemical function of the cell stack (10, 60), characterized in that the membrane (136) is arranged in a fluid-tight manner on / in a sealing frame (131), wherein the sealing frame (131) is arranged in a fluid-tight manner within the cell frame (120).

Description

[0001] The invention relates to a cell layer for an electrochemical cell stack, in particular a fuel cell stack or an electrolysis cell stack. Furthermore, the invention relates to an electrochemical cell stack, an electrochemical assembly, and an electrochemical system. State of the art

[0002] In an electrolyzer of an electrolyzer unit (stationary or mobile), e.g., an electrolyzer system, e.g., a fuel cell vehicle, an electrochemical conversion of water into hydrogen and oxygen takes place using electrical energy, generating heat. - In a low-temperature polymer electrolyte fuel cell of a fuel cell unit (mobile or stationary), e.g., a fuel cell system, e.g., a fuel cell vehicle, an electrochemical conversion of two reactants of two operating media into electrical energy and heat takes place.

[0003] The respective assembly can comprise at least one membrane electrode device, e.g., a membrane electrode assembly (MEA) with a PEM (proton exchange membrane) or an AEM (anion exchange membrane). Alternatively to the MEA, at least one electrode of a membrane electrode device can be arranged away from and directly opposite the membrane on a fluid transport structure of the membrane electrode device. The assembly can be configured with a plurality of membrane electrode devices arranged in a stack and bipolar plates arranged between them, forming an electrochemical cell stack with a plurality of individual cells. Task

[0004] Efforts are constantly underway to improve fuel cell units and electrolyzer units and to design them cost-effectively with regard to their materials, manufacturing costs, and / or maintenance costs. It is an object of the invention to provide an improved, particularly cost-effective, cell stack layer for an electrochemical cell stack, in particular a fuel cell stack or an electrolysis cell stack. Disclosure of the invention

[0005] The object of the invention is achieved by means of a cell layer for an electrochemical cell stack, by means of an electrochemical cell stack, by means of an electrochemical assembly, and by means of an electrochemical system. Advantageous developments, additional features, and / or advantages of the invention emerge from the dependent claims and the following description.

[0006] In the prior art, a CCM (catalyst-coated membrane) or an MEA for a single electrochemical cell of an electrochemical cell stack is secured in a cell frame of at least two parts of the single cell by means of a specially designed sub-sealing system. The sub-sealing system comprises at least two seals (ring seals, sealing cords, bead seals, etc.) per single cell, which are inserted into annular recesses of two sub-cell frames of the cell frame, opposite each other with respect to the CCM or the MEA. When the cell frame is assembled, the sub-cell frames accommodate the membrane between their seals and secure it in the cell frame, resulting in radial fluid tightness of the cell frame.

[0007] For the purposes of this specification, one or all radial directions (in particular, as a combination of the width and transverse directions of the cell stack) are perpendicular to an axial stacking direction (axial direction or vertical direction) of a cell stack whose cell frames extend circumferentially around the axial direction. Furthermore, for the purposes of this specification, a fluid is understood to mean a liquid and / or a gas, with a fluid-tight connection naturally being understood to mean a connection that can exhibit a tolerable leakage through the connection (e.g., a seam).

[0008] The cell layer according to the invention comprises at least one cell frame for radially fluid-sealing an electrochemically active region in the cell stack, as well as a membrane arranged within the cell frame for an electrochemical function of the cell stack, wherein the membrane is arranged fluid-tight on / in a sealing frame, and the sealing frame is arranged fluid-tight within the cell frame. The sealing frame can be arranged radially and / or axially fluid-tight relative to the cell frame in the cell frame. Furthermore, the cell frame can be realized as a single-part or multi-part, in particular a two-part, cell frame. The fuel cell stack can be designed, for example, as a PEM or an AEM fuel cell stack, and the electrolysis cell stack can be designed, for example, as a PEM, an AEM, an AEL (alkaline electrolysis), or a CO2 electrolysis cell stack.

[0009] The cell frame can have a radial outer section and a terraced radial inner collar projecting inwards therefrom. The inner collar is preferably integrally connected (see below) to the outer section. - The sealing frame can be seated axially on the inner collar, wherein the sealing frame is easily detachable or firmly connected to the cell frame. The former can be realized, for example, by a mechanical plug-in connection, and the latter can be designed, for example, such that the sealing frame is injected onto the inner collar and / or radially into the cell frame. In the first case, the sealing frame and the membrane, and in the second case the sealing frame and the cell frame, are designed as a two-part assembly, wherein their individual parts are provided almost next to one another.

[0010] Furthermore, the sealing frame can be located radially inside the outer section, wherein the sealing frame, analogous to the above, is easily detachable or firmly connected to the cell frame. The membrane can be arranged within the cell frame via the sealing frame, or the sealing frame can be mechanically pressed onto the inner collar by means of a fluid transport structure. Furthermore, only an inner circumferential surface, away from the inner collar, of the radially outer section of the cell frame can constitute a sealing surface for an electrode chamber of the cell layer. Furthermore, inner circumferential surfaces of both the inner collar and the sealing frame can constitute a sealing surface for an electrode chamber of the cell layer.

[0011] The membrane can be fixed to / in the sealing frame as a fluid-tight direct bond between the membrane and the sealing frame. The sealing frame can span the membrane installed therein. In a direct bond, the membrane cannot be integrally connected to the sealing frame. This means, for example, that the membrane and the sealing frame cannot be glued to one another. The direct bond can be permanently established with the aid of a third part or simply by the membrane and the sealing frame. In the first case, the third part can be designed as a fluid transport structure or a separate part. Furthermore, in a direct bond, the membrane can be inserted into the sealing frame and / or engage in it, for example, radially. In a direct bond, the sealing frame can hold, clamp and / or penetrate the membrane.

[0012] In direct assembly, the sealing frame can have a mounting groove (fixing groove) in which the membrane is fixed. By fixing the membrane in the specially provided mounting groove of the sealing frame, the membrane can be precisely positioned and also serves as a seal between two electrode compartments of the cell stack that are directly adjacent to each other via a membrane, or between an anode side and a cathode side of the cell layer. In this case, a radially outer section of the membrane can be inserted into the mounting groove as an assembly device. To assemble the membrane, a simple tool can be used, e.g. analogous to a global shape of the mounting groove. The membrane is placed on / in the sealing frame and then pressed into the mounting groove with the tool.

[0013] Furthermore, the mounting device can be inserted into the mounting groove as a multi-layer, in particular two-layer, mounting fold. This can be done, for example, in the form of a fit as a clearance (“soaking”, see below), interference fit, or press fit. Alternatively, the mounting device can be inserted into the mounting groove as a mounting projection formed on the membrane. Such an embodiment can again be used as a fit in the form of a clearance (“soaking”, see below), interference fit, or press fit. Furthermore, the mounting projection can be provided as a single piece on the membrane (see below) or integrally formed in the membrane (see below).

[0014] The mounting device can have the shape of a projection or a preferably substantially rectangular tab in an outer cross-section. Furthermore, a main extension direction of the mounting device can point substantially perpendicularly away from a plane of the membrane. Furthermore, apart from a possibly present radial outer edge portion, the membrane together with the mounting device can essentially have the shape of a Petri dish. Of course, the "Petri dish" can be substantially polygonal, rectangular, square, elliptical, circular, etc.

[0015] In a direct bond, the sealing frame and the membrane can be positioned against each other in such a way that essentially no fluid can pass between an unwatered membrane and the sealing frame, no fluid can pass between a watered membrane and the sealing frame, and / or the sealing frame and the membrane form a preferably simple labyrinth seal. The mounting device can be designed as a mounting fold or a mounting projection in each of the embodiments.

[0016] In the radial outer section of the membrane, the mounting device can be configured to run completely around the cell layer in the circumferential direction. The same naturally applies to the inner collar. The membrane can have no radial outer edge section or a radial outer edge section that lies essentially in one plane of the membrane. Furthermore, the membrane can be designed as a stand-alone membrane, a membrane-electrode unit (possibly with only a single catalyst layer), or a catalyst-coated membrane (likewise with possibly only a single catalyst layer). - The cell frame and / or sealing frame can be designed as an integral, one-piece, one-piece, two-piece, or multi-piece cell frame or sealing frame.

[0017] A one-piece design is understood to mean a design of the cell frame or sealing frame in which its components are fastened to one another in a force-fitting and / or form-fitting manner and the cell frame or sealing frame can preferably be separated again into its components without damage, if necessary with the use of a tool. - A materially (adhesively) one-piece design is understood to mean a design of the cell frame or sealing frame in which its individual parts are fastened to one another in a material-fitting manner (gluing, lamination, etc.) and the cell frame or sealing frame can preferably not be separated into individual parts without damaging one of its individual parts. The cohesion of the cell frame or sealing frame can also be created by means of a force-fitting and / or form-fitting connection (not in the case of an integral design).

[0018] An integral design refers to a design of the cell frame or sealing frame in which there is only a single component that can only be separated by destroying it. The cell frame or sealing frame is made from a single original piece and / or a single original mass (plastic melt), which is itself necessarily integral. Internal cohesion is achieved (exclusively) by adhesion and / or cohesion. - In all embodiments, the cell frame or sealing frame can additionally have lamination, coating, integral deposition, etc.

[0019] The mounting groove can be configured to extend substantially axially into a radial surface of the sealing frame. The sealing frame can be configured as a circumferentially closed ring. This ring can have a predominantly or substantially polygonal, rectangular, square, elliptical, or circular outline. The sealing frame can comprise, particularly as an injection-molded part, a sealing plastic, an elastomer, or a terpolymer. The sealing frame made of such an elastic material, particularly a thermoplastic elastomer or a terpolymer or synthetic rubber, meets high requirements regarding its environmental behavior (temperature requirements, sealing properties, etc.), durability, and / or mechanical properties.

[0020] The cell layer can have a fluid transport structure (see also below) radially within the cell frame on at least one large-area side of the membrane. In this case, a (first) fluid transport structure can radially overlap the direct bond of the membrane with the sealing frame. Furthermore, a (second) fluid transport structure can not radially overlap the direct bond of the membrane with the sealing frame. Furthermore, the fluid transport structure can be designed as a porous transport layer or a gas diffusion layer. In this case, the cell layer can in particular have, on the one hand, a porous transport layer and, on the other hand, a gas diffusion layer. In particular, the cell layer can be completely pre-assembled and stacked in chronological order with polar plates to form a cell stack.

[0021] By securing the membrane in the specially designed mounting groove in the sealing frame, it can be precisely positioned and also serve as an additional sealing system (labyrinth seal) between the anode and cathode sides of the membrane. Soaking (watering the individual electrochemical cell(s)) increases the membrane's volume, thereby enhancing the fixation and sealing effect. The fixation and sealing force can be further enhanced by pressing the sealing frame onto the fluid transport structure.

[0022] The cell stack according to the invention comprises a plurality of individual electrochemical cells, wherein cell layers of the cell stack are designed according to the invention. In the cell stack, a fluid transport structure, in particular a porous transport layer, can press against the direct composite in the region of the sealing frame. A force for this naturally originates from a clamping force of the cell stack. Furthermore, a fluid transport structure, in particular a porous transport layer, can press the mounting device into the mounting groove. As a result, in the assembled cell stack, the mounting device of the membrane can be permanently pressed into the mounting groove of the cell frame. Two bipolar plates each can clamp together a cell layer consisting of a cell frame, a sealing frame, a membrane, and fluid transport structures arranged on either side thereof.

[0023] The unit or system according to the invention comprises at least one electrochemical cell stack and a control unit for controlling and / or regulating the operation of the cell stack, wherein cell layers of the cell stack and / or the cell stack are / is designed according to the invention. - In an operating unit or system, the respective fixations (cf. above) of membranes on / in sealing frames are designed as fluid-tight direct composites of the respective membranes with the respective sealing frames, wherein the membranes increase in volume due to the soaking and the effect of the fixation and sealing is enhanced (cf. the horizontal, opposing arrows in the Fig. 3). Short description of the characters

[0024] The invention is explained in more detail below using exemplary embodiments with reference to the attached schematic and not-to-scale drawing. In the invention, a feature can be configured positively, i.e., present, or negatively, i.e., absent. In this specification, a negative feature is not explicitly explained as a feature unless it is important for the invention to be absent. This means that the invention actually made, and not one constructed by the prior art, consists in omitting this feature. The absence of a feature (negative feature) in an exemplary embodiment indicates that the feature may be optional (to a person skilled in the art). - In the merely exemplary and schematic figures (Fig.) of the drawing show: The Fig. 1 shows a simplified block diagram of an embodiment of a fuel cell unit with an electrochemical fuel cell stack for a fuel cell system of a fuel cell vehicle, the Fig. 2 shows a simplified block diagram of an embodiment of an electrolyzer unit with an electrochemical electrolysis cell stack for an electrolyzer system, e.g. an electrolyzer plant, and the Fig. 3 in a two-dimensional, schematic sectional view of a cell layer according to the invention for an electrochemical cell stack of an electrochemical unit ( Fig. 1 or Fig. 2). Embodiments of the invention

[0025] The invention is based on an electrochemical cell layer 100 (cf. Fig. 3) for an electrochemical cell stack 10, 60 of an electrochemical unit 1, 51 is explained in more detail. The unit 1, 51 can be used as a fuel cell unit 1 (cf. Fig. 1) for a mobile or stationary fuel cell system, or also a stationary or mobile electrolyzer unit 51 (cf. Fig. 2) be trained for an electrolyzer system.

[0026] The drawings depict only those sections of the fuel cell system or electrolyzer system that are necessary for understanding the invention. Although the invention is described and illustrated in detail using preferred embodiments, the invention is not limited to the disclosed embodiments. Other variations may be derived therefrom without departing from the scope of the invention.

[0027] The Fig. 1 and Fig. 2 each show an electrochemical aggregate 1, 51 ( Fig. 1: Fuel cell unit 1, Fig. 2: Electrolyzer unit 51) according to a general embodiment, with at least one, in particular a plurality of, to form an electrochemical cell stack 10, 60 or a stack 10, 60 ( Fig. 1: Fuel cell stack 10, Fig. 2: Electrolysis cell stack 60) bundled electrochemical single cells 11, 61 ( Fig. 1: Single fuel cells 11, Fig. 2: Individual electrolysis cells 61), which are housed in a preferably fluid-tight stacked housing 16, 66.

[0028] Each individual cell 11, 61 comprises an electrode chamber 12, 62 formed as an anode chamber 12, 62 and an electrode chamber 13, 63 formed as a cathode chamber 13, 63, which are spatially and electrically separated from one another by a membrane 136 or a membrane 136 of an MEA or a CCM. An electrically conductive fluid transport structure 140 is arranged in the respective electrode chamber 12, 13; 62, 63, which is in fluid communication with a bipolar plate 110 (see below). Alternatively, or in addition to an MEA or a CCM with only one electrode, at least one electrode can also be provided away from the membrane 136 on at least one fluid transport structure 140.

[0029] A membrane electrode device 15, 65 of the cell stack 10, 60 has a membrane 136 or a membrane 136 of an MEA or a CCM as well as fluid transport structures 140 on its large-area sides (see also the Fig. 3). A single fluid transport structure 140 may comprise a transport layer, a transport layer, a PTL 142 (Porous Transport Layer), a GDL 144 (Gas Diffusion Layer), a sintered metal element, a metallic sintered paper, a fiber element, a carbon layer, a carbon paper, a flow structure and / or a flow field, etc. The Fig. 1 and Fig. 2 not explicitly shown fluid transport structures 140 are arranged in the anode compartments 12 and the cathode compartments 13 of the cell stack 10, 60.

[0030] A bipolar plate 110 is arranged between two directly adjacent membrane electrode devices 15, 15; 65, 65 including a respective anode compartment 12, 62 and a respective cathode compartment 13, 63, which serves, among other things, to supply / discharge media 3 / 4, 5 / 6, 7 / 8; 53 / 54, 56 for an anode compartment 12, 62 of a first individual cell 11, 61 or a cathode compartment 13, 63 of a directly adjacent second individual cell 11, 61 and, moreover, realizes an electrically conductive connection between these individual cells 11, 11; 61, 61. - The cathode compartments 13, 63 and, if applicable, their common inflow area or their actual electrodes form a cathode 39, 89, and the anode compartments 12, 62 and, if applicable, their common inflow area or their actual electrodes form an anode 29, 79 of the cell stack 10, 60.

[0031] In principle, the membranes of the cell stack 10, 60 can comprise PEMs (proton exchange membranes) or AEMs (anion exchange membranes). PEMs are preferred for a fuel cell stack 10, and AEMs or PEMs are preferred for an electrolysis cell stack 60. In addition to the fuel cell unit 1 or the electrolyzer unit 51, the fuel cell system or electrolyzer system comprises peripheral system components, such as a control unit, which can be one of the fuel cell system or electrolyzer system itself, etc.

[0032] The following explanations only concern the electrochemical unit 1 as a fuel cell unit 1, e.g. according to the Fig. 1. - To supply the electrochemical cell stack 10 as fuel cell stack 10 with its actual operating media 3 (anode operating medium, actual fuel), 5 (cathode operating medium, usually air), the fuel cell unit 1 has an anode supply 20 and a cathode supply 30.

[0033] The anode supply 20 preferably comprises: a fuel reservoir 23 for the anode operating medium 3 (flowing in); an anode supply path 21 (medium path 21) with a pressure reducer, a shut-off valve, and / or a metering valve 27 (for example), as well as a jet pump 24 (jet pump 24, ejector 24); an anode exhaust gas path 22 (medium path 22) for an anode exhaust gas medium 4 (flowing out, usually into the environment 2); a fuel recirculation path 25 with a fluid conveying device 26 located therein; optionally, a water separator, preferably with a water tank.

[0034] The cathode supply 30 preferably comprises: a cathode supply path 31 (medium path 31) for the cathode operating medium 5 (flowing in, usually from the environment 2), with a fluid conveying device 33; a cathode exhaust gas path 32 (medium path 32) for a cathode exhaust gas medium 6 (flowing out, usually into the environment 2), preferably with a turbine 34, in particular for the fluid conveying device 33; a humidity exchanger 36, in particular a gas-to-gas humidifier 36; optionally a cathode-side stack bypass 35 (wastegate 35) between the cathode supply path 31 and the cathode exhaust gas path 32, with a bypass valve 37; optionally a water separator, preferably with a water tank.

[0035] The fuel cell unit 1 further comprises, in particular, a cooling medium supply 40 of a thermal system, through which the fuel cell stack 10 can be integrated into a cooling circuit for temperature control, preferably by means of its bipolar plates 110 (cooling medium paths 43). The cooling medium supply 40 comprises a cooling medium inlet path 41 and a cooling medium outlet path 42. The cooling medium 7 (inflowing) and 8 (outflowing) circulating in the cooling medium supply 40 are preferably conveyed by means of at least one cooling medium conveying device 44.

[0036] The following explanations concern only the electrochemical unit 51 as electrolyzer unit 51, e.g. according to the Fig. 2. - To supply the electrochemical cell stack 60 as electrolysis cell stack 60 with, for example, mildly alkaline water 53 as a supply medium 53, the electrolyzer unit 51 has a medium supply 70. And to remove the media 54, 56 of the cell stack 60, the electrolyzer unit 51 has a media removal 80.

[0037] The medium supply 70 preferably comprises: a medium reservoir 73 for the supply medium 53 (flowing in), a supply path 71 (medium path 71) and a conveying device 76 on / in the supply path 71. - The media removal 80 has at least one disposal path 81 (medium path 81) for a disposal medium 54 or a disposal medium 54 with oxygen back into the medium reservoir 73, optionally with a gas separator for oxygen, and / or in another direction (shown in dashed lines), e.g. into the environment 2.

[0038] A product medium 56 of the electrolyzer unit 51, i.e., the produced hydrogen 56, is transported away through a product medium path 82 of the media removal 80. A gas / liquid separator 83 with a valve 84 can be inserted in the product medium path 82 to separate the disposal medium 54 in the product medium path 82. The disposal medium 54 separated in the gas / liquid separator 83 can be conveyed back into the medium reservoir 73 or in another direction, e.g., into the environment 2, possibly by gravity. The produced hydrogen 56 can be stored, for example, in a hydrogen storage unit 90, wherein the product medium path 82 can flow directly into the hydrogen storage unit 90. Another method of transporting the hydrogen 56 away is, of course, possible.

[0039] Depending on the embodiment of the electrolyzer unit 51, a media guide in the cell stack 60 can be designed differently. In this case, it is possible to provide a temperature control system that differs from an electrochemical function of the cell stack 60, in particular water cooling, or to implement the temperature control system together with the electrochemical function of the cell stack 60.

[0040] In membrane electrode devices 65 with AEMs, it is possible to set up a supply of the supply medium 53, possibly exclusively on the anode side (dotted arrow at anode 79), in addition to an anode- and cathode-side supply, and possibly also as a cooling medium. Furthermore, in membrane electrode devices 65 with PEMs, it is possible to set up a supply of the supply medium 53, possibly exclusively on the cathode side (dotted arrow at cathode 89), in addition to an exclusively on the anode side.

[0041] The Fig. 3 shows, due to a clamping force (cf. the vertical block arrows pointing towards each other) of a cell stack 10, 60 stacked in the axial direction Ar, a cell layer 100 clamped between two (bi-)polar plates 110 with a single cell frame 120, a single membrane 136 and two optional fluid transport structures 140 (cf. below) on both sides of the membrane 136 axially Ar and radially Rr within the cell frame 120. The preferably integral, possibly also two- or multi-part, cell frame 120 is preferably designed to be completely circumferential in the circumferential direction Ur of the cell layer 100, wherein the essentially planar extending membrane 136 is arranged in an inner (frame) opening of the cell frame 120.

[0042] A respective electrode for an electrochemical function of the cell layer 100 can be provided on the membrane 136 or on a side directly adjacent to the membrane 136 on a fluid transport structure 140. Mixed forms are applicable here, i.e., an electrode on the membrane 136 and an electrode on the fluid transport structure 140 that is opposite the first electrode with respect to the membrane 136. This means that the membrane 136 can be designed as a standalone membrane 136 (having no electrodes), as an MEA 136 or CCM 136 coated with an electrode on one side or with electrodes on both sides, etc.

[0043] The cell frame 120 serves for a radial Rr fluid sealing of an electrochemically active region of the respective individual cell 15, 65 in the cell stack 10, 60. In this case, the cell frame 120 serves for holding or clamping the membrane 136 within the cell frame 120 via a radial Rr arranged therein, ie in particular coaxial, sealing frame 131, wherein the membrane 136 is fixed on / in the sealing frame 131 in such a way that the membrane 136 and the sealing frame 131 form a preferably essentially fluid-tight direct bond 135 in the region of their mutual fixation.

[0044] In the direct composite 135, the membrane 136 can be mounted on / in the sealing frame 131 such that the sealing frame 131 holds, clamps, and / or penetrates the membrane 136, or the membrane 136 is inserted into and / or engages the sealing frame 131. The direct composite 135 is designed such that the sealing frame 131 and the membrane 136 are seated against one another in such a way that essentially no fluid (liquid, gas; see above) can pass between an unwatered and / or watered membrane 136 and the sealing frame 131.

[0045] The sealing frame 131 can preferably be configured in a fluid-tight manner on / in the cell frame 120 prior to the assembly of the membrane 136. Alternatively, the membrane 136 can initially be configured in a fluid-tight manner on / in a single sealing frame 131, with such a sealing frame-membrane arrangement 131, 136 subsequently being configured in a fluid-tight manner on / in the cell frame 120. In both variants, the cell frame 120 has a radial inner collar 121, which is arranged coaxially in the outer section 125 and on which the sealing frame 131 rests axially.

[0046] In one embodiment - see the Fig. 3 - the cell frame 120 has a radial Rr outer section 125 which is preferably substantially rectangular in its cross-section and which defines an axial Ar height of the cell layer 100, as well as an inner collar 121 which is integrally connected thereto. The inner collar 121 protrudes in a terrace-like manner and radially Rr inwards from the outer section 125, wherein an axial Ar outer side of the inner collar 121 forms a substantially planar surface with an axial Ar outer side of the outer section 125 (bottom in the Fig. 3).

[0047] Furthermore, the radial Rr outer section 125 of the cell frame 120 can, starting from its two axial Ar outer sides, each have a sealing groove 128 which preferably runs completely around the circumferential direction Ur of the cell layer 100 and which, in addition to a radial Rr extension for a width of a seal, is naturally also configured in the axial direction Ax into the outer section 125. In the respective sealing groove 128, in the cell layer 100 mounted in the cell stack 10, 60, at least one seal (not shown) is configured, which seals an anode-side or a cathode-side electrode chamber 12 / 13, 62 / 63 of the cell stack 10, 60 from the outside in the radial direction Rr with respect to a (bi-)polar plate 110.

[0048] One of the axial Ar outside (bottom of the Fig. 3) the inner side 123 of the inner collar 121, which is opposite the inner collar 121 in the axial direction Ar, lies approximately at half the axial Ar height of the outer section 125. This inner side 123 (terrace surface) of the inner collar 121 projects radially Rr inwards into the cell frame 120, with the sealing frame 131 being provided in a fluid-tight manner on the inner side 123. The sealing frame 131 preferably extends radially Rr outwards as far as an inner circumferential surface of the radial Rr outer section 125 and radially Rr inwards, preferably as far as an inner circumferential surface of the inner collar 121. The inner circumferential surfaces of the inner collar 121 and of the sealing frame 131 are aligned in the axial direction Ar. Furthermore, the sealing frame 131, which runs in the circumferential direction Ur, is naturally built axially Ar on the inner collar 121.

[0049] A circumferential Ur, radial Rr outer section of the membrane 136 rests axially Ar on the sealing frame 131, wherein a region (mounting device 132) of the outer section in this embodiment is further fixed in the sealing frame 131 through an axially Ar outer surface 133 of the sealing frame 131. For this purpose, the sealing frame 131 has, starting from its axially Ar outer surface 133, a mounting groove 132 or fixing groove 132 extending axially Ax into the sealing frame 131, in which the membrane 136 is fixed.

[0050] The mounting groove 132 can only enter the sealing frame 131 ( Fig.3) or extend to the axial inner side 123 of the inner collar 121 (not shown). In the second case, the sealing frame 131 is divided into two parts in the radial direction Rr, with the two parts arranged coaxially to one another. Furthermore, it is possible to arrange the mounting groove 132 between the sealing frame 131 and another outer radial inner section or an inner circumferential surface of the outer section 125 (not shown).

[0051] For this purpose, the membrane 136 preferably has an integral mounting device 138, which is inserted and fixed in the mounting groove 132. As a result, the membrane 136 is naturally also received or clamped on / in the sealing frame 131 and fixed to / in the cell frame 120. The mounting groove 132 and the mounting device 138 are preferably provided so as to extend completely around the circumference Ur.

[0052] The mounting device 138 can be designed as a multi-layer, in particular two-layer, mounting fold 138 or as a mounting projection 138 formed on the membrane 136 and inserted into the mounting groove 132. In this case, the mounting device 138 clamps in the mounting groove 132, which is further reinforced by subsequent wetting of the individual cells 15, 65 of the cell stack 10, 60 and thus wetting of the membrane 136. In this case, the mounting device 138 and the mounting groove 132 form a simple labyrinth seal; a more complex labyrinth seal is, of course, applicable in other embodiments.

[0053] The cell layer 100 can have one or two fluid transport structures 140, wherein the respective fluid transport structure 140 is arranged in the cell stack 10, 60 in an anode-side or cathode-side electrode chamber 12 / 13, 62 / 63 of the cell layer 100 and accordingly forms an anode-side or cathode-side fluid transport structure 140. Here, the respective fluid transport structure 140 is arranged on a large-area side of the membrane 136 within the cell frame 120.

[0054] Here, a fluid transport structure 140, (142) can rest axially Ar over the membrane 136 and the sealing frame 131 on the radial Rr inner collar 121, and in the clamped cell stack 10, 60, further secure the direct bond 135 of the membrane 136 with the sealing frame 131. This means that the fixation of the membrane 136 with the sealing frame 131 is additionally secured (fixed). The other fluid transport structure 140, (144) can be arranged within the inner circumferential surfaces of the radial Rr inner collar 121 and the sealing frame 131. The first fluid transport structure 140, 142 can be designed as a porous transport layer 142, and the second fluid transport structure 140, 144 can be designed as a gas diffusion layer 144. Other fluid transport structures 140 (see above) are, of course, applicable in each case.

[0055] The cell frame 120 has (vertical / horizontal) medium passage recesses 109 extending therethrough. Furthermore, the cell frame 120 can have (horizontal / vertical) medium channels 129, which, starting from the medium passage recesses 109, open into a respective electrode chamber 12 / 13, 62 / 63, which is delimited by the cell frame 120 in the circumferential direction Ur. This means that the respective electrode chamber 12 / 13, 62 / 63 is in fluid communication with at least one medium passage recess 109. The media channels 129 can be configured, for example, as grooves 129 in the cell frame 120.

[0056] The medium passage recesses 109 and the medium channels 129 serve to supply and discharge the electrode chamber 12 / 13, 62 / 63 with and from a medium 3 / 5, 53 / 54. Additionally, the cell layer 100 can comprise at least one polar plate 110, wherein the respective polar plate 110 can be designed in particular as a bipolar plate 110 or as a monopolar plate 110 (not shown).

Claims

[1] Cell layer (100) for an electrochemical cell stack (10, 60), in particular a fuel cell stack (10) or an electrolysis cell stack (60), at least comprising a cell frame (120) for radially (Rr) fluidly sealing an electrochemically active region in the cell stack (10, 60), and a membrane (136) arranged within the cell frame (120) for an electrochemical function of the cell stack (10, 60), characterized by , that the membrane (136) is arranged fluid-tight on / in a sealing frame (131), wherein the sealing frame (131) is arranged fluid-tight within the cell frame (120). [2] Cell layer (100) according to the preceding claim, characterized by that the cell frame (120) has a radial (Rr) outer section (125) and a terraced radial (Rr) inner collar (121) projecting inwards therefrom, and: • the sealing frame (131) is seated in the axial direction (Ar) on the inner collar (121), wherein the sealing frame (131) is easily detachable or firmly connected to the cell frame (120), • only an inner circumferential surface of the radial (Rr) outer section (125) of the cell frame (120) constitutes a sealing surface for an electrode space (12 / 13, 63 / 62) of the cell layer (100), and / or • inner circumferential surfaces of both the inner collar (121) and the sealing frame (131) constitute a sealing surface for an electrode space (13 / 11, 62 / 63) of the cell layer (100). [3] Cell layer (100) according to one of the preceding claims, characterized by that a fixation of the membrane (136) on / in the sealing frame (131) is designed as a fluid-tight direct connection (135) of the membrane (136) with the sealing frame (131), wherein preferably: • in the direct connection (135) the membrane (136) is not integrally connected to the sealing frame (131), • the direct connection (135) is permanently established with the aid of a third part or only by the membrane (136) and the sealing frame (131), and / or • in the direct connection (135) the membrane (136) is inserted into and / or engages the sealing frame (131). [4] Cell layer (100) according to one of the preceding claims, characterized by that in the direct connection (135) the sealing frame (131) has a mounting groove (132) in which the membrane (136) is fixed, wherein preferably: • a radial (Rr) outer portion of the membrane (136) is inserted into the mounting groove (132) as a mounting device (138), and / or • the mounting device (138) is inserted into the mounting groove (132) as a multi-layer, in particular two-layer, mounting fold (138), or • the mounting device (138) is inserted into the mounting groove (132) as a mounting projection (138) formed on the membrane (136). [5] Cell layer (100) according to one of the preceding claims, characterized by , that: • the mounting device (138) has in an outer cross-section the shape of a projection or a preferably substantially rectangular tab, • a main extension direction of the mounting device (138) points substantially perpendicularly (Ar) away from a plane of the membrane (136), and / or • apart from a possibly present radial (Rr) outer edge section (137), the membrane (136) together with the mounting device (138) has substantially the shape of a Petri dish. [6] Cell layer (100) according to one of the preceding claims, characterized by that in the direct connection (135) the sealing frame (131) and the membrane (136) are seated against each other in such a way that: • between an unwatered membrane (136) and the sealing frame (131) essentially no fluid can pass, • no fluid can pass between a watered membrane (136) and the sealing frame (131), and / or • the sealing frame (131) and the membrane (136) preferably form a simple labyrinth seal. [7] Cell layer (100) according to one of the preceding claims, characterized by , that: • in the radial (Rr) outer section of the membrane (136), the mounting device (138) is arranged to completely encircle the cell layer (100) in the circumferential direction (Ur), • the membrane (136) has no or a radial (Rr) outer edge portion (137) which lies substantially in a plane of the membrane (136), and / or • the membrane (136) is designed as a membrane (136) in isolation, a membrane electrode assembly (136) or a catalyst-coated membrane (136). [8] Cell layer (100) according to one of the preceding claims, characterized by , that: • the mounting groove (132) is arranged to extend substantially in the axial direction (Ar) into a radial surface (Rr) of the sealing frame (131), • the sealing frame (131) is designed as a ring closed in the circumferential direction (Ur), • the sealing frame (131), in particular as an injection-molded part (131), comprises a sealing plastic, an elastomer or a terpolymer. [9] Cell layer (100) according to one of the preceding claims, characterized by that the cell layer (100) has a fluid transport structure (140) radially inside the cell frame (120) on at least one large-area side of the membrane (136), wherein preferably: • a fluid transport structure (140, 142) radially (Rr) overlaps the direct composite (135) of the membrane (136) with the sealing frame (131), • a fluid transport structure (140, 144) does not radially (Rr) overlap the direct composite (135) of the membrane (136) with the sealing frame (131), and / or • the fluid transport structure (140) is designed as a porous transport layer (140, 142) or a gas diffusion layer (140, 144). [10] Electrochemical cell stack (10, 60), in particular fuel cell stack (10) or electrolysis cell stack (60), for an electrochemical unit (1, 51), in particular a fuel cell unit (1) or an electrolyzer unit (51), with a plurality of electrochemical individual cells (11, 51), characterized by that cell layers (100) of the cell stack (10, 60) are formed according to one of the preceding claims. [11] Electrochemical cell stack (10, 60) according to the preceding claim, characterized by that in the cell stack (10, 60): • a fluid transport structure (140), in particular a porous transport layer (140, 142), presses onto the direct composite (135) in the region of the sealing frame (131), • a fluid transport structure (140), in particular a porous transport layer (140, 142), which presses the mounting device (138) into the mounting groove (132), and / or • two bipolar plates (110) each clamp together a cell layer (100) consisting of a cell frame (120), a sealing frame (131), a membrane (136) and fluid transport structures (140, 140; 141, 142) arranged on both sides thereof. [12] Electrochemical unit (1, 51), in particular fuel cell unit (1) or electrolyzer unit (51), or electrochemical system, in particular fuel cell system or electrolyzer system, with at least one electrochemical cell stack (10, 60) and a control device for controlling and / or regulating operation of the cell stack (10, 60), characterized by , that Cell layers (100) of the cell stack (10, 60) and / or the cell stack (10, 60) are / is formed according to one of the preceding claims.

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