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 radially (Rr) liquid-tightening an electrochemically active region in the cell stack (10, 60), and a membrane (130) arranged within the cell frame (120) for an electrochemical function of the cell stack (10, 60), wherein a fixation of the membrane (130) on / in the cell frame (120) is designed as a substantially liquid-tight direct bond (101) of the membrane (130) with the cell frame (120).

Description

[0001] The invention relates to a cell layer for an electrochemical cell stack of an electrochemical assembly. 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] In this case, 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). As an alternative to the MEA, at least one electrode of a membrane electrode device can be arranged apart from and directly opposite a 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, which form 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, in particular more 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, in particular a fuel cell stack or an electrolysis cell stack, for an electrochemical unit; and by means of an electrochemical unit, in particular a fuel cell unit or an electrolyzer unit, and an electrochemical system, in particular a fuel cell system or an electrolyzer 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 or an MEA for an individual electrochemical cell of an electrochemical cell stack is secured in an at least two-part cell frame of the individual cell via a specially designed sub-sealing system. The sub-sealing system comprises at least two seals (ring seals, sealing cords, bead seals, etc.) per individual cell, which are inserted into annular recesses of two sub-cell frames of the cell frame, opposite one another 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] Within the scope of this specification, one or all radial directions (in particular as combinations of width and transverse directions of the cell stack) are perpendicular to an axial stacking direction (axial direction or vertical direction) of the cell stack in question, the cell frames of which run circumferentially around the axial direction.

[0008] The cell layer according to the invention comprises at least one cell frame for radially sealing an electrochemically active region in the cell stack, as well as a membrane arranged within the cell frame for electrochemical function of the cell stack, wherein the membrane is fixed to / in the cell frame as a substantially liquid-tight direct bond of the membrane to the cell frame. The fuel cell stack can be configured, for example, as a PEM or AEM fuel cell stack, and the electrolysis cell stack can be configured, for example, as a PEM, AEM, AEL (alkaline electrolysis), or CO2 electrolysis cell stack.

[0009] In direct bonding, the membrane cannot be integrally bonded to the cell frame. This means, for example, that the membrane and cell frame cannot be glued together. The direct bond can be permanently established with the aid of a third part or simply by the membrane and the cell frame. In direct bonding, the cell frame can hold, clamp, and / or penetrate the membrane. Furthermore, in direct bonding, the membrane can be inserted into the cell frame and / or engage with it. The cell frame can span the membrane installed therein.

[0010] In direct assembly, the cell frame can have a mounting groove in which the membrane is fixed. By fixing the membrane in the specially provided mounting groove, the membrane can be precisely positioned and also serves as a seal between an anode side and a cathode side of the cell stack or cell layer. In this case, a radially outer section of the membrane can be inserted into the mounting groove as a mounting device. - A simple tool, e.g. in a global form of the mounting groove, can be used to mount the membrane. The membrane is placed on / in the cell frame and then pressed into the mounting groove with the tool.

[0011] 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 an oversize 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 an oversize or press fit. Furthermore, the mounting projection can be provided as a single piece on the membrane or be integrally formed in the membrane (see analogously to the following).

[0012] The mounting device can have the shape of a projection or a preferably substantially rectangular tab in cross-section. A main direction of extension of the mounting device can point substantially perpendicularly away from a plane of the membrane. Furthermore, apart from a possibly present radial outer edge section, the membrane together with the mounting device can essentially have the shape of a Petri dish. The "Petri dish" can, of course, be substantially rectangular, square, elliptical, or circular.

[0013] In the direct bond, the cell frame and the membrane can be attached to one another in such a way that essentially no liquid can pass between an unwatered membrane and the cell frame, that no liquid can pass between a watered membrane and the cell frame, and / or that the cell frame and the membrane form a preferably simple labyrinth seal.

[0014] In the radially outer section of the membrane, the mounting device can be arranged to extend completely around the cell layer in the circumferential direction. Furthermore, the membrane can have no radial outer edge section or a radial outer edge section that can lie essentially in one plane of the membrane. Furthermore, the membrane can be designed as a stand-alone membrane, a membrane-electrode assembly (possibly with only a single catalyst layer), or a catalyst-coated membrane (also possibly with only a single catalyst layer). In each of the embodiments, the mounting device can be designed as a mounting fold or mounting projection.

[0015] The cell frame can have an inner collar, wherein the membrane is fixed on / in the inner collar, thus forming the direct connection. This means that the membrane and the inner collar form the direct connection between the membrane and the cell frame. Furthermore, the mounting groove can be designed to extend essentially in the axial direction of the cell layer into a radial surface of the inner collar. Furthermore, the inner collar can adjoin a radial outer section of the cell frame radially inward in a terraced manner. In this case, the inner collar is preferably integrally connected to the outer section (cf. analogously to the following). - The cell frame can be designed as an integral, a one-piece, a one-piece, a two-piece, or a multi-piece cell frame.

[0016] A one-piece design is understood to mean a design of the cell frame in which its components are fastened to one another in a force-fitting and / or form-fitting manner and the cell 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 in which its individual parts are fastened to one another in a material-fitting manner (gluing, lamination, etc.) and the cell frame can preferably not be separated into individual parts without damaging one of its individual parts. The cohesion of the cell frame can also be created by means of a force-fitting and / or form-fitting connection (not in the case of an integral design).

[0017] An integral design refers to a cell frame design in which there is only a single component that can only be separated by destruction. The cell frame is manufactured 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 can additionally have lamination, coating, integral deposition, etc.

[0018] In addition to the direct connection, an additional sealing element or sealing system can be installed between the cell frame and the membrane, e.g., radially inside and / or radially outside. In this case, it is possible, for example, to install a circumferential groove in the inner collar, in which a sealing element can be installed, which additionally fluid-tightens the inner collar or the cell frame with respect to the membrane. Furthermore, a sealing material can be installed between the inner collar and the membrane.

[0019] The liquid-tight direct composite can also be designed as a fluid-tight and / or gas-tight direct composite. Furthermore, the cell frame can be designed as a circumferentially closed ring with a predominantly or substantially rectangular, square, elliptical, or circular outline.

[0020] The cell layer can have a fluid transport structure (see also below) within the cell frame on at least one large-area side of the membrane. A (first) fluid transport structure can radially overlap the direct bond of the membrane to the cell frame. Furthermore, a (second) fluid transport structure can not radially overlap the direct bond of the membrane to the cell frame. Furthermore, the fluid transport structure can be configured as a porous transport layer or a gas diffusion layer. In particular, the cell layer can have, on the one hand, a porous transport layer and, on the other hand, a gas diffusion layer.

[0021] 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 inner collar of the cell 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. Furthermore, two bipolar plates can each clamp together a cell layer consisting of a cell frame, a membrane, and fluid transport structures arranged on either side thereof.

[0022] 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 operational unit or system, the respective fixations (cf. above) of membranes on / in cell frames are designed as liquid-tight direct composites of the respective membranes with the respective cell frames, wherein the so-called 'soaking' (watering of the individual cells) causes the membranes to increase in volume and the effect of the fixation and sealing is enhanced (cf. the horizontal, opposing arrows in the Fig. 3). - A liquid-tight direct bond is understood to mean a direct bond which can have a tolerable liquid leakage through the direct bond. Short description of the characters

[0023] 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 purely exemplary and schematic figures (Fig.) of the drawing: 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

[0024] 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.

[0025] The drawings show only those sections of the fuel cell system or electrolyzer system that are necessary for an understanding of 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.

[0026] 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, 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.

[0027] 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 130 or a membrane 130 of an MEA or a CCM (catalyst-coated membrane). 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 130 on at least one fluid transport structure 140.

[0028] A membrane electrode device 15, 65 of the cell stack 10, 60 has a membrane 130 or a membrane 130 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 include 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.

[0029] 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, to create 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.

[0030] 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.

[0031] 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.

[0032] 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 with preferably a water tank.

[0033] 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.

[0034] 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.

[0035] The following explanations only concern 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.

[0036] 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.

[0037] 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 medium 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.

[0038] 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 that differs from an electrochemical function of the cell stack 60, in particular water cooling, or to implement the temperature control together with the electrochemical function of the cell stack 60.

[0039] 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, 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 (dotted arrow at cathode 89).

[0040] 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 bipolar plates 110 with a single cell frame 120, a single membrane 130 and two optional fluid transport structures 140 (cf. below) on both sides of the membrane 130 axially Ar and radially Rr within the cell frame 120. The 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 130 is arranged in an inner (frame) opening of the cell frame 120.

[0041] A respective electrode for an electrochemical function of the cell layer 100 can be provided on the membrane 130 or on a side directly adjacent to the membrane 130 on a fluid transport structure 140. Mixed forms are applicable here, i.e., an electrode on the membrane 130 and an electrode on the fluid transport structure 140 that is opposite the first electrode with respect to the membrane 130. This means that the membrane 130 can be designed as a membrane 130 in isolation (having no electrodes), as an MEA 130 or CCM 130 coated with an electrode on one side or with electrodes on both sides, etc.

[0042] The cell frame 120 serves for a radial Rr liquid-tightness of an electrochemically active region of the respective individual cell 15, 65 in the cell stack 10, 60. The cell frame 120 serves to hold or clamp the membrane 130 within the cell frame 120, wherein the membrane 130 is fixed to / in the cell frame 120 in such a way that the membrane 130 and the cell frame 120 form a preferably substantially liquid-tight direct bond 101 in the region of their mutual fixation. Furthermore, the direct bond 101 can be fluid-tight and / or gas-tight.

[0043] In the direct composite 101, the membrane 130 can be mounted on / in the cell frame such that the cell frame 120 holds, clamps, and / or penetrates the membrane 130, or the membrane 130 is inserted into and / or engages the cell frame 120. The direct composite 101 is designed such that the cell frame 120 and the membrane 130 are seated against one another in such a way that essentially no liquid (fluid, gas; see above) can pass between an unwatered and / or watered membrane 130 and the cell frame 120.

[0044] For one embodiment (cf. Fig. 3) of the direct composite 101, the cell frame 120 has a radial Rr outer section 125, which is preferably substantially rectangular in its cross-section and defines an axial Ar height of the cell layer 100, as well as an inner collar 121 integrally adjoining it. The inner collar 121 protrudes in a terraced manner and radially Rr inwards from the outer section 125, wherein an axial Ar outer side of the inner collar 121 and an axial Ar outer side of the outer section 125 form a substantially planar surface (bottom in the Fig. 3).

[0045] Furthermore, the outer section 125 of the cell frame 120 can, starting from its two axial outer sides Ar, 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 129, 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 its 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 outwardly in the radial direction Rr.

[0046] An inner side 123 of the inner collar 121 opposite the axial Ar outer side of 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, wherein a radial Rr outer region of the membrane 130 rests on the inner side 123 and which, in this embodiment, is further fixed in the inner collar 121 through the inner side 123 (mounting device 132).

[0047] For this purpose, the inner collar 121 has, starting from its inner side 123, a mounting groove 122 extending axially Ax into the inner collar 121, in which the membrane 130 is fixed. For this purpose, the membrane 130 has a preferably integral mounting device 132, which is inserted and fixed in the mounting groove 122. This, of course, also fixes the membrane 130 to / in the cell frame 120. The mounting groove 122 and the mounting device 132 are preferably provided to extend completely around the circumferential direction Ur.

[0048] The mounting device 132 can be designed as a multi-layer, in particular two-layer, mounting fold 132 or as a mounting projection 132 formed on the membrane 130 and inserted into the mounting groove 122. In this case, the mounting device 132 clamps in the mounting groove 122, which is further reinforced by subsequent watering of the individual cells 15, 65 of the cell stack 10, 60 and thus watering of the membrane 130. In this case, the mounting device 132 and the mounting groove 122 form a simple labyrinth seal; a more complex labyrinth seal is, of course, applicable in other embodiments.

[0049] 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 space 12 / 13, 62 / 63 of the cell layer 100 and accordingly forms an anode-side or cathode-side fluid transport structure 140. The respective fluid transport structure 140 is arranged on a large-area side of the membrane 130 within the cell frame 120.

[0050] Here, a fluid transport structure 140, (142) can rest axially on the radial inner collar 121 and, in the clamped cell stack 10, 60, fix the direct composite 101 of the membrane 130 with the cell frame 120. This means that the fixation of the membrane 130 to the cell frame 120 is additionally secured (fixed). The other fluid transport structure 140, (144) can be arranged between the radial inner edges of the inner collar 121. 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.

[0051] 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 electrode chamber 12 / 13, 62 / 63 is in fluid communication with the medium passage recesses 109. The media channels 129 can be configured, for example, as grooves 129 in the cell frame 120.

[0052] 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. - For example, in the case of an electrolysis cell stack 60, the medium passage recesses 109 are designed as chimney(s) 109 and the media channels 129 as delta channels 129. In this case, the medium passage recesses 109 and medium channels 129 supply and discharge the electrode chamber 63 with the supply medium 53 and the disposal medium 54, while the medium passage recesses 109 and medium channels 129 also discharge the electrode chamber 62 from the product medium 56.

[0053] In addition, the cell layer 100 may comprise at least one polar plate 110, wherein the polar plate 110 may be designed in particular as a bipolar plate 110 or also 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) sealing an electrochemically active region in the cell stack (10, 60), and a membrane (130) arranged within the cell frame (120) for an electrochemical function of the cell stack (10, 60), characterized by , that a fixation of the membrane (130) on / in the cell frame (120) is designed as a substantially liquid-tight direct bond (101) of the membrane (130) with the cell frame (120). [2] Cell layer (100) according to the preceding claim, characterized by , that: • in the direct composite (101) the membrane (130) is not integrally connected to the cell frame (120), • the direct connection (101) is permanently established with the aid of a third part or only by the membrane (130) and the cell frame (120), • in the direct connection (101) the cell frame (120) holds, clamps and / or penetrates the membrane (130), and / or • in the direct connection (101) the membrane (130) is inserted into and / or engages the cell frame (120). [3] Cell layer (100) according to one of the preceding claims, characterized by that in the direct connection (101) the cell frame (120) has a mounting groove (122) in which the membrane (130) is fixed, wherein preferably: • a radial (Rr) outer portion of the membrane (130) is inserted into the mounting groove (122) as a mounting device (132), and / or • the mounting device (132) is inserted into the mounting groove (122) as a multi-layer, in particular two-layer, mounting fold (132), or • the mounting device (132) is inserted into the mounting groove (122) as a mounting projection (132) formed on the membrane (130). [4] Cell layer (100) according to one of the preceding claims, characterized by , that: • the mounting device (132) has the shape of a projection or a preferably substantially rectangular tab in a cross section, • a main extension direction of the mounting device (132) points substantially perpendicularly away from a plane of the membrane (130), and / or • apart from a possibly present radial (Rr) outer edge section (131), the membrane (130) together with the mounting device (132) has substantially the shape of a Petri dish. [5] Cell layer (100) according to one of the preceding claims, characterized by that in the direct connection (101) the cell frame (120) and the membrane (130) are attached to each other in such a way that: • between an unwatered membrane (130) and the cell frame (120) essentially no liquid can pass, • no liquid can pass between a watered membrane (130) and the cell frame (120), and / or • the cell frame (120) and the membrane (130) preferably form a simple labyrinth seal. [6] Cell layer (100) according to one of the preceding claims, characterized by , that: • in the radial (Rr) outer section of the membrane (130), the mounting device (132) is arranged to completely encircle the cell layer (100) in the circumferential direction (Ur), • the membrane (130) has no or a radial (Rr) outer edge portion (131) which lies substantially in a plane of the membrane (130), and / or • the membrane (130) is designed as a membrane (130) in isolation, a membrane electrode assembly (130) or a catalyst-coated membrane (130). [7] Cell layer (100) according to one of the preceding claims, characterized by that the cell frame (120) has an inner collar (121), wherein: • the membrane (130) is fixed to / in the inner collar (121) and the direct connection (101) is formed in this way, • the mounting groove (122) is arranged to extend substantially in the axial direction (Ar) of the cell layer (100) into a radial surface (Rr) of the inner collar (121), and / or • the inner collar (121) is terraced and adjoins a radial (Rr) outer section (125) of the cell frame (120) radially (Rr) inside. [8] Cell layer (100) according to one of the preceding claims, characterized by , that: • in addition to the direct connection (101), an additional sealing element or sealing system is installed between the cell frame (120) and the membrane (130), • the liquid-tight direct composite (101) is further designed as a fluid-tight and / or gas-tight direct composite (101), and / or • the cell frame (120) is designed as a ring closed in the circumferential direction (Ur) with a particularly mainly or substantially rectangular, square, elliptical or circular floor plan. [9] Cell layer (100) according to one of the preceding claims, characterized by that the cell layer (100) has a fluid transport structure (140) within the cell frame (120) on at least one large-area side of the membrane (130), wherein preferably: • a fluid transport structure (140, 142) radially (Rr) overlaps the direct composite (101) of the membrane (130) with the cell frame (120), • a fluid transport structure (140, 144) does not overlap the direct composite (101) of membrane (130) with the cell frame (120) radially (Rr), 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 (101) in the region of the inner collar (121) of the cell frame (120), • a fluid transport structure (140), in particular a porous transport layer (140, 142), which presses the mounting device (132) into the mounting groove (122), and / or • two bipolar plates (110) each clamp together a cell layer (100) consisting of a cell frame (120), a membrane (130) 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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