Cell layer for an electrochemical assembly

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) fluid-sealing an electrochemically active region in the cell stack (10, 60), and a membrane (131) arranged within the cell frame (120) for an electrochemical function of the cell stack (10, 60), and the membrane (131) is designed as a membrane-seal device (130), the membrane (131) being part of a membrane-seal device (130), and the membrane (131) has, on / in the radially (Ra) outer circumferential portion (133) thereof, a membrane seal (132) which runs around completely in the circumferential direction (Ur) of the cell layer (100) and which can be or is designed to be fluid-tight with respect to the cell frame (120).

Description

[0001] Description

[0002] title

[0003] Cell layer for an electrochemical aggregate

[0004] 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.

[0005] State of the art

[0006] 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.

[0007] In this case, the respective unit 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 away from and directly opposite the membrane on a fluid transport structure of the membrane electrode device. The unit can be configured with a plurality of membrane electrode devices or analogues arranged in a stack and bipolar plates arranged between them, forming an electrochemical cell stack with a plurality of individual cells.

[0008] Task

[0009] Efforts are constantly underway to improve electrolyzer units and fuel cell 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 an electrolysis cell stack or a fuel cell stack.

[0010] Disclosure of the invention

[0011] 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.

[0012] 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.

[0013] 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, i.e., possibly a two-phase mixture. A fluid-tight connection is naturally understood to mean a connection that can exhibit a tolerable leakage through the connection (e.g., a seam, joint, etc.).

[0014] The cell layer according to the invention comprises a 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, and the membrane is part of a membrane sealing device, wherein the membrane has, on / in its radially outer circumferential section, a membrane seal that runs completely around the circumferential direction of the cell layer and is or can be configured to be fluid-tight with respect to the 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.

[0015] The membrane seal can be arranged radially and, if necessary, axially fluid-tight relative to the cell frame on / in the cell frame. Apart from any radial outer edge section of the membrane, the membrane sealing device can have the shape of a disk (membrane) with an outer bead (membrane seal). The outer bead disk can, of course, be essentially regular polygonal, rectangular, square, elliptical, circular, etc.; the same can apply to the cell frame and / or the cell layer. Other shapes are, of course, applicable.

[0016] A fluid transport structure for the cell layer(s) can be arranged or configured within the cell frame in such a way that, by means of the fluid transport structure, at least the membrane seal of the membrane sealing device can be subjected to a sealing force (see the small arrows in Fig. 3) with respect to the cell frame. For this purpose, the fluid transport structure presses axially against the membrane seal. The membrane seal can fluid-tighten a substantial radial inner region of the membrane or fluid-tighten substantially the entire membrane radially outward.

[0017] The diaphragm seal can be arranged radially inside the radially outer circumferential section or radially outside on the radially outer circumferential section of the diaphragm. The diaphragm seal can be integrally connected to the diaphragm (see analogous below), whereby this connection preferably firmly connects the diaphragm seal to the diaphragm. The diaphragm seal is, of course, preferably integrally formed (again, see analogous below). Furthermore, the diaphragm seal can be connected to the diaphragm by a mechanical bond, a thermomechanical bond, and / or vulcanization.

[0018] The membrane can be secured essentially axially centrally and / or coaxially to / in the membrane seal. Furthermore, the membrane seal can have a regular cross-section and / or outline in a mechanically unloaded state. The cross-section or outline can be, in particular, elliptical, circular, polygonal, rectangular, or square. The membrane seal can have a sealing lip that extends completely around the circumference on at least one side. With this circumferential side, the membrane seal preferably rests against an inner collar (see below) of the cell frame.

[0019] The membrane seal may comprise a sealing plastic, an elastomer, a silicone, an EPDM (ethylene propylene diene rubber) and / or a rubber.

[0020] The diaphragm seal made of such an elastic material, particularly a thermoplastic elastomer, terpolymer, or synthetic rubber, meets stringent requirements regarding environmental performance (temperature requirements, sealing properties, etc.), durability, and / or mechanical properties. A different material may be used for the diaphragm seal if necessary.

[0021] The cell frame can have a radial outer section and a terraced inner collar projecting radially inward therefrom. The radial inner collar is preferably integrally connected to the outer section (see analogous below). - In this case, only an inner circumferential surface of the outer section away from the inner collar can constitute a radial sealing surface for an individual electrode space of the cell layer. Furthermore, only an inner circumferential surface of the inner collar can constitute a radial sealing surface for an individual electrode space of the cell layer. Furthermore, the membrane seal can be seated on an axial inner side of the inner collar and can be firmly or easily detachably connected to the cell frame.

[0022] One or the axial inner side of the inner collar can have a substantially flat surface or a sealing groove that runs completely around the circumference. The diaphragm seal of the diaphragm sealing device can be at least partially arranged in the sealing groove of the axial inner side of the inner collar. In this case, an interference fit or compression fit is used when the diaphragm seal is subjected to mechanical stress. Radially away from the sealing groove, the inner collar can have a step to compensate for the thickness of the diaphragm.

[0023] A fluid transport structure can be set up or can be set up on the membrane-sealing device within the cell frame opposite the sealing groove. The fluid transport structure can in particular be designed as a porous transport layer (PTL). Other forms of fluid transport structure (see below) are of course applicable. - In a cell layer installed or mechanically clamped together, for example, in an electrochemical cell stack, the membrane seal sits on the axial inside of the radial inner collar or on / in the sealing groove in such a way that essentially no fluid can pass radially between the membrane seal and the inner collar. Here, and of course also in other embodiments, the fluid transport structure presses the membrane seal into its sealing groove.

[0024] The membrane sealing device may have one or no radial membrane outer edge section, which lies essentially in one plane of the membrane (radially inwardly offset membrane seal). The membrane sealing device may be designed as a stand-alone membrane sealing device or as a membrane electrode unit (possibly with only a single catalyst layer). The membrane of the membrane sealing device may be designed as a catalyst-coated membrane (also possibly with only a single catalyst layer). The cell frame may be designed as an integral, one-piece, one-piece, two-piece, or multi-piece cell frame.

[0025] 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 be separated again into its components, preferably 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 achieved by means of a force-fitting and / or form-fitting connection (not in the case of an integral design).

[0026] An integral design refers to a cell frame design in which there is only a single component that can only be separated by destroying it. The cell 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 can additionally feature lamination, coating, integral deposition, etc.

[0027] 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 membrane seal. Furthermore, a (second) fluid transport structure can not radially overlap the membrane seal (this is accommodated radially within a circumferential side of the inner collar). 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 preassembled and stacked in chronological order with (bi-)polar plates to form a cell stack. The electrochemical 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 membrane seal in a region of the radial inner collar. Furthermore, a fluid transport structure, in particular a porous transport layer, can press the membrane seal into the sealing groove. This can of course also be applied to the cell layer. A respective mechanical force for this may originate in part from a clamping force of the cell stack. As a result, in the assembled cell stack, the membrane seal of the membrane sealing device can be permanently pressed into the sealing groove of the cell frame or onto the radial inner collar. Furthermore, apart from the stack ends, two bipolar plates can each clamp together a cell layer consisting of a cell frame, a membrane sealing device, and fluid transport structures arranged on either side thereof.

[0028] The electrochemical unit according to the invention or the electrochemical system according to the invention comprises at least one electrochemical cell stack and a control device for controlling and / or regulating operation of the cell stack, wherein cell layers of the cell stack and / or the cell stack are or are designed according to the invention.

[0029] Short description of the characters

[0030] 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 positive, i.e. present, or negative, i.e. absent. In this specification, a negative feature is not explicitly explained as a feature unless it is important according to the invention that it 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 shows that the feature may be optional (to a person skilled in the art). - In the purely exemplary and schematic figures (Fig.) of the drawing show: 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, 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 Fig. 3 shows 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 2).

[0031] Embodiments of the invention

[0032] The invention is explained in more detail using an electrochemical cell layer 100 (see Fig. 3) for an electrochemical cell stack 10, 60 of an electrochemical unit 1, 51. The unit 1, 51 can be designed as a fuel cell unit 1 (see Fig. 1) for a mobile or stationary fuel cell system, or as a stationary or mobile electrolyzer unit 51 (see Fig. 2) for an electrolyzer system.

[0033] The drawings depict 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.

[0034] 1 and 2 each show an electrochemical unit 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, individual electrochemical cells 11, 61 (Fig. 1: individual fuel cells 11, Fig. 2: individual electrolysis cells 61) bundled 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), which are accommodated in a preferably fluid-tight stack housing 16, 66. 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 131 or a membrane 131 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 131 on at least one fluid transport structure 140.

[0035] A membrane electrode device 15, 65 of the cell stack 10, 60 comprises a membrane 131 or a membrane 131 of an MEA or a CCM, as well as fluid transport structures 140 on its large-area sides (see also Fig. 3). An individual fluid transport structure 140 can 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 fluid transport structures 140, not explicitly shown in Figs. 1 and 2, are arranged in the anode compartments 12 and the cathode compartments 13 of the cell stack 10, 60.

[0036] 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 furthermore 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.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.

[0037] The following explanations relate only to the electrochemical unit 1 as a fuel cell unit 1, for example according to Fig. 1. - To supply the electrochemical cell stack 10 as a 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The following explanations relate only to the electrochemical unit 51 as an electrolyzer unit 51, e.g., as shown in Fig. 2. To supply the electrochemical cell stack 60 as an electrolysis cell stack 60 with, e.g., 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 from the cell stack 60, the electrolyzer unit 51 has a media removal 80.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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 the 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 the cathode 89), in addition to an exclusively on the anode side.

[0046] By way of example, 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 131 and two (for the cell layer 100) optional fluid transport structures 140 (cf. below) on both sides of the membrane 131 axially Ar and radially Rr within the cell frame 120. The preferably integral, optionally 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 131 is arranged in an inner (frame) opening of the cell frame 120.

[0047] A respective electrode for an electrochemical function of the cell layer 100 can be provided on the membrane 131 or on a side directly adjacent to the membrane 131 on a fluid transport structure 140. Mixed forms are applicable here, i.e., an electrode on the membrane 131 and an electrode on the fluid transport structure 140 that is opposite the first electrode with respect to the membrane 131. This means that the membrane 131 can be designed as a membrane 131 in isolation (having no electrodes), as an MEA 131 or CCM 131 coated with an electrode on one side or with electrodes on both sides, etc.

[0048] The membrane 131 is here integrated into a membrane sealing device 130. The membrane sealing device 130 preferably has exclusively the membrane 131 in its interior region and, on / in a radially outer circumferential section of the membrane 131, a membrane seal 132 that runs completely in the circumferential direction Ur. The membrane seal 132 can be arranged on the outermost periphery or in a periphery (radially outer circumferential section) of the membrane 131 on / in the membrane sealing device 130, wherein the membrane 131 is arranged in particular axially Ar centrally or centrally and / or coaxially on / in the membrane seal 132, or vice versa.

[0049] The cell frame 120 serves for a radial Rr fluid seal of an electrochemically active region of the respective individual cell 15, 65 in the cell stack 10, 60. Furthermore, the cell frame 120 serves, in particular by means of a radial Rr inner collar 121 arranged therein, for holding or clamping (e.g. with a fluid transport structure 140, see below) the membrane sealing device 130 within the cell frame 120, wherein or by means of which the membrane sealing device 130 is held or fixable on / in the cell frame 120.

[0050] In cell layer 100, the membrane seal 132 of the membrane sealing device 130 can be configured or is configured to form a fluid-tight connection with the cell frame 120. A sealing force for this fluid-tight connection, e.g., pressing or pressing the membrane seal 132 against / onto / into the cell frame 120, preferably originates from a fluid transport structure 140, which can be configured or is configured within the cell frame 120. This means that the fluid transport structure 140 exerts a mechanical force on the membrane seal 132, e.g., due to the clamping force of the cell stack 10, 60, such that it is elastically deformed, whereby no fluid can pass between the membrane seal 132 and the cell frame 120.

[0051] In one embodiment - see Fig. 3 - the cell frame 120 has a radial Rr outer section 125 which is preferably substantially rectangular or square in its cross section (Rr-Ar) (not shown in Fig. 3), which defines an axial Ar height of the cell layer 100, and an inner collar 121 which is integrally connected thereto. The inner collar 121 projects radially Rr inwards from the outer section 125 in a terraced manner, wherein one of two axial Ar outer sides of the inner collar 121 forms a substantially planar surface with an axial Ar outer side of the outer section 125 (bottom in Fig. 3).

[0052] The radial Rr outer section 125 of the cell frame 120 preferably has, starting from its two axial Ar outer sides, 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, is naturally also arranged 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 arranged, 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.

[0053] An axial Ar inner side 123 of the inner collar 121, opposite the above-mentioned axial Ar outer side (bottom in Fig. 3) 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 of the inner collar 121 (terrace surface) projects radially Rr inwards into the cell frame 120, wherein the membrane sealing device 130 with its membrane seal 132 can be provided or is provided in a fluid-tight manner on the inner side 123.

[0054] A radially Ra outer circumferential portion 133 of the membrane sealing device 130 or of the membrane 131 lies or sits axially Ar on the inner collar 121 or its axial Ar inner side 123, wherein the fluid transport structure 140 presses the radially Ra outer circumferential portion 133 onto the inner collar 121 and holds it in position. The membrane seal 132 of the membrane sealing device 130 is preferably received in a sealing groove 122 provided in the axial Ar inner side 123 of the inner collar 121.

[0055] The fluid transport structure 140 presses the membrane seal 132 into a bottom of the sealing groove 122, e.g., due to the clamping force of the cell stack 10, 60. This deforms the membrane seal 132, creating a fluid-tight connection between the membrane seal 132 and the bottom of the sealing groove 122 or the axial inner side 123. Thus, the fluid present in the respective electrode chamber 12 / 13, 63 / 62 of the cell layer 100 cannot bypass the membrane 131.

[0056] One or two fluid transport structures 140 may be associated with the cell layer 100, 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. The respective fluid transport structure 140 is arranged on a large-area side of the membrane 131 within the cell frame 120.

[0057] One of the two fluid transport structures 140, (142) presses the membrane seal 132 onto the radial inner collar 121 and is radially received exclusively within the inner circumferential surface of the radial outer section 125. The other fluid transport structure 140, (144) is radially received exclusively within the inner circumferential surface of the radial inner collar 121. The former fluid transport structure 140, 142 can be configured as a porous transport layer 142, and the latter fluid transport structure 140, 144 can be configured as a gas diffusion layer 144. Other fluid transport structures 140 (see above) are, of course, applicable.

[0058] 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.

[0059] The medium passage recesses 109 and the medium channels 129 serve to supply and discharge the electrode space 12 / 13, 62 / 63 with and from a medium 3 / 5, 53 / 54. - In addition, 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

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 the radial (Rr) fluid sealing of an electrochemically active region in the cell stack (10, 60), and a membrane (131) arranged within the cell frame (120) for an electrochemical function of the cell stack (10, 60), characterized in that the membrane (131) is a component of a membrane sealing device (130), wherein the membrane (131) has, on / in its radially (Ra) outer circumferential section (133), a membrane seal (132) which runs completely around the circumferential direction (Ur) of the cell layer (100), which can be set up or is set up in a fluid-tight manner with respect to the cell frame (120).

2. Cell layer (100) according to the preceding claim, characterized in that a fluid transport structure (140, 142) for the cell layer(s) (100) can be set up or is set up within the cell frame (120) in such a way that at least the membrane seal (132) of the membrane sealing device (130) can be or is subjected to a sealing force with respect to the cell frame (120) by means of the fluid transport structure (140, 142).

3. Cell layer (100) according to one of the preceding claims, characterized in that: • the membrane seal (132) fluid-seales a substantial radial (Rr) inner region of the membrane (131) or fluid-seales substantially the entire membrane (131) radially (Rr) outwards, • the membrane seal (132) is arranged radially (Ra) inside the radially (Ra) outer peripheral portion (133) or radially (Ra) outside the radially (Ra) outer peripheral portion (133) of the membrane (131), • the membrane seal (132) is integrally connected to the membrane (131) and by this connection the membrane seal (132) is firmly connected to the membrane (131), and / or • the membrane seal (132) is connected to the membrane (131) by a mechanical bond, a thermomechanical bond and / or vulcanization.

4. Cell layer (100) according to one of the preceding claims, characterized in that: • the membrane (131) is fixed substantially axially (Ar) centrally and / or coaxially to / in the membrane seal (132), • the membrane seal (132) has a regular cross-section (Rr-Ar) and / or plan in a mechanically unloaded state, • the membrane seal (132) has a sealing lip on at least one side that runs completely around the circumference (Ur), and / or • the membrane seal (132) comprises a sealing plastic, an elastomer, a silicone, an EPDM and / or a rubber.

5. Cell layer (100) according to one of the preceding claims, characterized in that the cell frame (120) has a radial (Rr) outer section (125) and a terraced radial (Rr) inner collar (121) projecting inwards therefrom, wherein preferably: • only an inner circumferential surface of the outer section (125) away from the inner collar (121) constitutes a radial (Rr) sealing surface for a single electrode space (12 / 13, 63 / 62) of the cell layer (100), • only an inner circumferential surface of the inner collar (121) constitutes a radial (Rr) sealing surface for a single electrode space (12 / 13, 63 / 62) of the cell layer (100), and / or • the membrane seal (132) is located on an axial (Ar) inner side (123) of the inner collar (121) and is firmly or easily detachably connected to the cell frame (120).

6. Cell layer (100) according to one of the preceding claims, characterized in that: • one / the axial (Ar) inner side (123) of the inner collar (121) has a substantially flat surface or a sealing groove (122) that runs completely around the circumference (Ur), • the membrane seal (132) of the membrane sealing device (130) is at least partially arranged in the sealing groove (122) of the axial (Ar) inner side (123) of the inner collar (121), and / or • a fluid transport structure (140, 142) can be or is set up on the membrane sealing device (130) opposite the sealing groove (122) within the cell frame (120).

7. Cell layer (100) according to one of the preceding claims, characterized in that: • the membrane sealing device (130) has one or no radial (Rr) membrane outer edge section which lies substantially in a plane of the membrane (131), • the membrane sealing device (130) is designed as a membrane sealing device (130) in isolation or as a membrane electrode unit, and / or • the membrane (131) of the membrane sealing device (130) is designed as a catalyst-coated membrane (131).

8. Cell layer (100) according to one of the preceding claims, characterized in that the cell layer (100) has on at least one large-area side of the membrane (131) a fluid transport structure (140) radially (Rr) within the cell frame (120), wherein preferably: • a / the fluid transport structure (140, 142) radially (Rr) overlaps the membrane seal (132), • a fluid transport structure (140, 144) does not overlap the membrane seal (132) 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).

9. 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 electrolysis unit seuraggregat (51), with a plurality of electrochemical individual cells (11, 51), characterized in that cell layers (100) of the cell stack (10, 60) are formed according to one of the preceding claims.

10. Electrochemical cell stack (10, 60) according to the preceding claim, characterized in that in the cell stack (10, 60): • a fluid transport structure (140), in particular a porous transport layer (140, 142), presses on the membrane seal (132) in a region of the radial (Rr) inner collar (121), • a fluid transport structure (140), in particular a porous transport layer (140, 142), which presses the membrane seal (132) into the sealing groove (122), and / or • two bipolar plates (110) each clamp together a cell layer (100) comprising a cell frame (120), a membrane sealing device (130) and fluid transport structures (140, 140; 141, 142) arranged on both sides thereof.

11. 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 an operation of the cell stack (10, 60), characterized in 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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