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) running around in the circumferential direction (Ur) of the cell layer (100) for radially (Rr) liquid-tightening at least one electrode space (12 / 13, 62 / 63) of the cell stack (10, 60), wherein a representative volume element of a cell frame core (121) of the cell frame (120) is designed to be stiffer than a representative volume element of the same size of a cell frame shell (122) of the cell frame (120), in which the cell frame core (121) is at least embedded.

Description

The invention relates to a cell layer for an electrochemical cell stack of an electrochemical unit. The invention further relates to an electrochemical cell stack, an electrochemical aggregate and an electrochemical system.Prior ArtIn an electrolyser of an electrolyser assembly (stationary or mobile), e.g. of an electrolyser system, for example of an electrolyser plant or as an electrolyser plant, electrochemical conversion of water takes place with the aid of electrical energy into hydrogen and oxygen with formation of heat. In a low-temperature polymer electrolyte fuel cell of a fuel cell assembly (mobile or stationary), e.g. of a fuel cell system, for example of a fuel cell vehicle, electrochemical conversion of two reactants of two operating media into electrical energy and heat takes place.In this case, the relevant aggregate can comprise at least one membrane electrode device with, for example, 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 may be arranged away from and directly opposite a membrane on a fluid transport structure of the membrane electrode device. the assembly may be formed with a plurality of membrane electrode devices arranged in a stack and bipolar plates arranged therebetween, which form an electrochemical cell stack (stack) having a plurality of individual cells.Object Setting Up To AchieveEfforts are constantly being made to improve fuel cell assemblies and electrolyser assemblies and to design them at low cost with respect to their materials, production costs and / or maintenance costs.Disclosure of the InventionThe 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 electrolyser unit, and an electrochemical system, in particular a fuel cell system or an electrolyser system.The cell layer according to the invention comprises at least one cell frame, which preferably extends completely in the circumferential direction of the cell layer, for the radial liquid sealing of at least one electrode space of the cell stack, wherein a representative volume element of a cell frame core (insert, stabilizing core) of the cell frame is formed more rigidly than an equally large representative volume element of a cell frame jacket of the cell frame, in which the cell frame core is at least embedded or which surrounds the cell frame core at least partially. - The fuel cell stack can be formed, for example, as a PEM or an AEM fuel cell stack, and the electrolysis cell stack can be formed, for example, as a PEM, an AEM, an AEL (alkaline electrolysis) or a CO 2- electrolysis cell stack. In this case, the electrolysis cell stack can be designed in particular for high-pressure electrolysis.Within the scope of this specification, one or all radial directions (in particular as compositions of width and transverse directions of the cell stack) stand perpendicular to an axial stacking direction (axial direction or vertical direction) of the cell stack, the cell frames of which circulate around the axial direction in the circumferential direction. The relevant representative volume element is of course a mathematical object, i.e. a mathematical volume shape, wherein volume elements of equal size have both the same volume and the same shape. And "representative" is to be understood as meaning that the volume element is a volume element typical of the cell frame core or the cell frame jacket and therefore substantially any desired volume element given a sufficient small size.Here, a mass density of the cell frame core may be greater than a mass density of the cell frame jacket. Furthermore, a material of the cell frame core can be different from a material of the cell frame jacket. In addition, the cell frame core can comprise a metal or a metal alloy and / or the cell frame jacket can comprise a plastic. Other materials for such an insert for guaranteeing stability of the cell frame, such as glass fiber composite mats, ceramic, etc., are of course applicable. - The cell frame can be designed as a ring closed in the circumferential direction. Furthermore, the cell frame can have a mainly or substantially rectangular, square, elliptical or circular outline. Furthermore, the cell frame core of the cell frame jacket can be formed in one part or in multiple parts.In a cross section of the cell frame, the cell frame jacket cannot surround the cell frame core on all sides or only on one side in the circumferential direction thereof. If a cross section of the cell frame is mentioned, this means a cross section of the cell frame that is only one-sided, i.e. a cross section of a strand of the cell frame that runs in the circumferential direction of the cell layer. Furthermore, the cell frame core or its parts can be embedded on all sides in the cell frame jacket.The cell frame core can be configured centrally, centered or coaxial in the cell frame jacket in the axial direction and / or in the radial direction of the cell layer. Furthermore, a radial extent of the (single- or multi-part) cell frame core can be at least about: 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% in each case ±2% of a radial extent of the cell frame jacket. Furthermore, an axial extent of the (single- or multi-part) cell frame core can be at least about: 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% in each case ±2% of an axial extent of the cell frame jacket.The cell frame jacket can have a sealing groove for receiving a seal, wherein a material of the cell frame jacket is preferably present in the groove base. That is to say that the sealing groove preferably does not open the cell frame jacket apart from the cell frame core. The cell frame jacket can each have such a sealing groove on both sides of the cell frame core in the axial direction. The sealing groove can be configured in a circumferential direction so as to extend completely circumferentially in the cell frame jacket. - A (ring) seal which can be accommodated in a sealing groove serves for sealing the cell layer with respect to a bipolar plate or a membrane.The cell frame can have medium passage recesses which pass through its cell frame jacket and preferably its cell frame core. Of course, the cell frame can also have medium passage recesses which pass by the cell frame core, which is used in particular for a multi-part design of the cell frame core for an individual cell frame. Furthermore, the cell frame jacket can have medium channels, via which the medium passage recesses and the electrode space are in fluid communication.In one embodiment, the cell frame can radially delimit a single electrode space for the cell stack, wherein a fluid transport structure is configured in the free space provided for this purpose in the cell layer. Furthermore, a membrane can be arranged in the cell layer on a large-area side of the fluid transport structure of this cell frame. The fluid transport structure can be designed as a porous transport layer or a gas diffusion layer; another fluid transport structure (cf. below) can of course be used. - In addition, the cell layer can comprise two cell frames and a membrane arranged therebetween, wherein a fluid transport structure is arranged in neither, one or both cell frames.Furthermore, in one embodiment, the cell frame can radially delimit exactly two electrode spaces for the cell stack, wherein a fluid transport structure is respectively configured in the free spaces provided for this purpose in the cell layer. In addition, a membrane can be arranged in the cell layer between the fluid transport structures of this cell frame. In this case, one fluid transport structure can be designed as a porous transport layer and the other as a gas diffusion layer; a respective different fluid transport structure (cf. below) can of course be used. - In addition, the cell layer can comprise a single cell frame and a membrane arranged substantially centrally therein in the axial direction, wherein a fluid transport structure is arranged on one side, on both sides or on no side of the membrane.In the upper first embodiment (cf. also FIG. 3 ), two such cell frames relating to one another can span the respective membrane therebetween. And in this second embodiment (cf. also FIGS. 4 and 5 ), the respective membrane can be stretched e.g. on / in an inner waistband (terrace) of the single cell frame.The cell frame jacket and / or the cell frame core or the parts thereof can have a mainly or substantially rectangular cross section. The cell layer may further comprise a membrane and / or a bipolar plate. In this case, the membrane can be configured as a membrane in isolation, a membrane electrode unit (optionally with only a single catalyst layer), a catalyst-coated membrane (likewise with optionally only a single catalyst layer) etc. The cell frame can be formed as an injection-molded part with the cell frame core as an insert part. The cell frame core is inserted into a mold or a tool and subsequently encapsulated with a plastic for the cell frame jacket. The cell frame jacket can be formed as an integral, materially one-piece or one-piece cell frame jacket.A one-piece configuration is understood to mean a configuration of the cell frame jacket in which its components are firmly and / or positively fixed to one another and the cell frame jacket can preferably be separated back into its components without damage, optionally using a tool. - A materially (adhesively) one-piece configuration is understood to mean a configuration of the cell frame jacket in which its individual parts are firmly fixed to one another (adhesive bonding, lamination, etc.) and the cell frame jacket can preferably not be separated into individual parts without damage to one of its individual parts. The cohesion of the cell frame jacket can furthermore be produced by means of a force fit and / or form fit (not in the case of an integral configuration).An integral configuration is understood to mean a configuration of the cell frame jacket in which there is only a single component which can be divided only by destruction thereof. The cell frame jacket is made of a single original piece and / or a single original mass (plastic melt), which in turn is necessarily integral. Internal cohesion takes place (exclusively) by means of adhesion and / or cohesion. In all embodiments, the cell frame jacket can additionally have lamination, coating, integral deposition, etc.The cell stack according to the invention comprises a plurality of electrochemical individual cells, wherein cell layers of the cell stack are formed according to the invention. - In the cell stack, in each case two bipolar plates can clamp together a single cell layer comprising a single cell frame, a membrane and fluid transport structures arranged on both sides of the membrane.Alternatively, in the cell stack, two bipolar plates can respectively clamp together an anode-side cell layer with a fluid transport structure configured therein, a membrane and a cathode-side cell layer with a fluid transport structure configured therein. Furthermore, in the cell stack, the sealing grooves of two cell frames directly adjacent to one another with respect to a membrane can be configured offset with respect to one another in the radial direction in such a way that they do not have a radial overlap region.The aggregate 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 adjusting an operation of the cell stack, wherein cell layers of the cell stack are formed according to the invention and / or the cell stack is formed according to the invention.Brief Description of the FiguresThe invention is explained in more detail below on the basis of exemplary embodiments with reference to the appended schematic drawing, which is not true to scale. In the invention, a feature may be positive, i.e. present, or negative, i.e. absent. In this specification, a negative feature is not explicitly explained as a feature unless the invention claims the absence thereof. That is, the invention actually made, rather than one constructed by the prior art, is to omit this feature. The absence of a feature (negative feature) in an exemplary embodiment shows that the feature is optional (as the case may be, a person skilled in the art).FIG. 1 shows a simplified block diagram of an embodiment of a fuel cell assembly having 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 electrolyser assembly having an electrochemical electrolysis cell stack for an electrolyser system, for example an electrolyser installation, andFIGS. 3 to 5 are two-dimensional schematic sectional views each of a cell layer according to the invention for an electrochemical cell stack of an electrochemical unit (FIG. 1 or 2 ).Embodiments of the InventionThe invention is explained in more detail on the basis of an electrochemical cell layer 100 (cf. FIGS. 3 to 5 ) for an electrochemical cell stack 10, 60 of an electrochemical unit 1, 51. In this case, the unit 1, 51 can be designed as a fuel cell unit 1 (cf. FIG. 1 ) for a mobile or stationary fuel cell system, or else a stationary or mobile electrolyser unit 51 (cf. FIG. 2 ) for an electrolyser system.Only those sections of the fuel cell system or electrolyser system are shown in the drawing which are necessary for an understanding of the invention. - Although the invention is described and illustrated in more detail by preferred exemplary embodiments, the invention is not restricted by the disclosed exemplary embodiments. Other variations can be derived therefrom without departing from the scope of protection of the invention.FIGS. 1 and 2 each show an electrochemical unit 1, 51 (FIG. 1 : fuel cell unit 1, FIG. 2 : electrolyser unit 51) according to a general embodiment, having 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) which are bundled to form an electrochemical cell stack 10, 60 or a stack 10, 60 (FIG. 1 : fuel cell stack 10, FIG. 2 : electrolysis cell 60) and are accommodated in a preferably fluid-tight stack housing 16, 66.Each individual cell 11, 61 comprises an electrode space 12, 62 designed as anode space 12, 62 and an electrode space 13, 63 designed as cathode space 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 configured in the respective electrode space 12, 13; 62, 63 and is in fluid communication with a bipolar plate 110 (cf. below). Alternatively, or in addition to an MEA or a CCM with only one electrode, at least one electrode may also be provided on at least one fluid transport structure 140 away from the membrane 130.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 and fluid transport structures 140 on their large-area sides (cf. also FIGS. 3 to 5 ). A single fluid transport structure 140 may include a transport layer, a transport layer, a porous transport layer (PTL 142), a gas diffusion layer (GDL 144), a sintered metal member, a metallic sintering paper, a fiber member, 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 configured in the anode spaces 12 and the cathode spaces 13 of the cell stack 10, 60.A bipolar plate 110 is arranged between two membrane electrode devices 15, 15; 65, 65, 65 directly adjacent to one another, including a relevant anode chamber 12, 62 and a respective cathode chamber 13, 63 which serves, inter alia, for the supply / discharge of media 3 / 4, 5 / 6, 7 / 8; 53 / 54, 56 for an anode chamber 12, 62 of a first individual cell 11, 61 or a cathode chamber 13, 63 of a second individual cell 11, 61 directly adjacent thereto and additionally implements an electrically conductive connection between these individual cells 11, 11; 61, The cathode chambers 13, 63 and optionally their common inflow region or their actual electrodes form a cathode 39, 89, and the anode chambers 12, 62 and optionally their common inflow region 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 have PEMs (proton exchange membranes) or AEMs (anion exchange membranes). In the present case, PEMs are preferred for a fuel cell stack 10 and AEMs or PEMs for an electrolysis cell stack 60 The fuel cell system or the electrolyser system comprises, in addition to the fuel cell assembly 1 or the electrolyser assembly 51, peripheral system components, such as a control device, which can be one of the fuel cell system or the electrolyser system itself, etc.The following embodiments relate only to the electrochemical unit 1 as a fuel cell unit 1, for example according to FIG. 1 : For supplying 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.The anode supply 20 preferably comprises: a fuel storage 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 (by way of example), and also 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 delivery device 26 located therein; optionally a water separator with preferably a water container.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), with preferably a turbine 34, in particular for the fluid conveying device 33; a moisture 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 with preferably a water container.The fuel cell assembly 1 further comprises in particular a cooling medium supply 40 of a thermal system, through which the fuel cell stack 10 can be incorporated in a cooling circuit in a heat-transferring manner for temperature control, preferably by means of its bipolar plates 110 (cooling medium paths 43). The cooling medium supply 40 comprises a cooling medium inflow path 41 and a cooling medium outflow path 42. The cooling medium 7 circulating in the cooling medium supply 40 is conveyed (in the direction of flow), 8 (in the direction of flow) preferably by means of at least one cooling medium conveying device 44.The following embodiments relate only to the electrochemical unit 51 as an electrolyser unit 51, for example according to FIG. 2 : In order to supply the electrochemical cell stack 60 as an electrolysis cell stack 60 with, for example, possibly mild alkaline water 53 as a supply medium 53, the electrolyser unit 51 has a medium supply 70. And for removing the media 54, 56 of the cell stack 60, the electrolyser assembly 51 has a media removal 80.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 medium 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.A product medium 56 of the electrolyser assembly 51, i.e. the hydrogen 56 produced, is transported away through a product medium path 82 of the medium removal 80. In this case, a gas / liquid separator 83 with a valve 84 can be used in the product medium path 82 in order to separate off 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, for example into the environment 2, optionally gravitationally. The hydrogen 56 produced may be stored, for example, in a hydrogen storage 90, wherein the product medium path 82 may open directly into the hydrogen storage 90. Another removal of the hydrogen 56 is of course possible.Depending on an embodiment of the electrolyser assembly 51, a media guide in the cell stack 60 can be of different design. In this case, it is possible to provide a temperature control, in particular water cooling, that is different from an electrochemical function of the cell stack 60 or to realize the temperature control together with the electrochemical function of the cell stack 60.In the case of membrane electrode devices 65 with AEMs, it is possible to arrange the supply medium 53 as a cooling medium, if appropriate, in addition to an anode- and cathode-side supply, an optionally exclusively anode-side (dotted arrow at the anode 79). Furthermore, in the case of membrane electrode devices 65 with PEMs, it is possible, in addition to an exclusively anode-side, an optionally exclusively cathode-side 89 supply of supply medium 53, optionally also to configure it as cooling medium (dotted arrow in the case of the cathode 89).For example, FIG. 3 shows, due to a mechanical clamping force (cf. the vertical block arrows, which are directed in each case towards one another), of a cell stack 10, 60 stacked in the axial direction Ar clamped between two bipolar plates 110: a (first) cell layer 100, a membrane 130 and a (second) cell layer 100, wherein the membrane 130 is clamped between the two cell layers 100. The respective cell layer 100 comprises a cell frame 120, which is preferably formed so as to be completely circumferential in the circumferential direction Ur of the cell layer 100, wherein the membrane 130, which extends in a planar manner, closes a through-recess in the cell layers 100 constituted by the inner (frame) openings of the two cell frames 120 over its entire surface. In this case, the membrane 130 may or may not be associated with a cell layer 100 (cf. also below).In an alternative illustrated, for example, in FIGS. 4 and 5, the two cell layers 100 can preferably be combined integrally to form a single cell layer 100 (single cell frame jacket 122, cf. below). In such an embodiment, the membrane 130 is arranged essentially centrally in the single (frame) opening of the cell frame 120 axially Ar, wherein the membrane 130 is fixed inside, e.g. on a radial Rr inner wall or an inner collar (terrace), in the cell frame 120.Axially Ar on both sides of the membrane 130 in each cell frame 120 (FIG. 3 ) is a fluid transport structure 140 (cf. below) or in the single cell frame 120 (FIGS. 4 and 5 ) is in each case a fluid transport structure 140 (cf. below), wherein the one fluid transport structure 140 (FIG. 3 ) or both fluid transport structures 140 (FIGS. 4 and 5 ) can be assigned to the cell layer 100 or not. The fluid transport structure 140 in question is arranged axially Ar and radially Rr within the respective cell frame 120 (FIG. 3 ) or in the single cell frame 120 (FIGS. 4 and 5 ).A respective electrode for an electrochemical function can be provided on the membrane 130 or on a side directly adjacent to the membrane 130 on a fluid transport structure 140. Here, mixed forms are applicable, i.e. an electrode on the membrane 130 and an electrode on that fluid transport structure 140 which is opposite the first electrode with respect to the membrane 130. That is, the membrane 130 may be configured as a membrane 130 alone (having no electrodes), as an MEA 130 or CCM 130 coated with an electrode on one side or with electrodes on both sides, etc.The cell frame 120 serves for a radial Rr fluid-tight or fluid-tight sealing of an electrochemically active region in at least one individual cell 15, 65 in the cell stack 10, 60. For this purpose, a preferably radial Rr outer section of the cell frame 120 can have, in each case starting from its two axial Ar outer sides, a sealing groove 128 which preferably runs completely in the circumferential direction Ur and which, besides a radial Rr extension for a width of a seal 129 in question, is of course also configured to run in an axial direction Ax into the radial Rr outer section. In the relevant sealing groove 128, at least its seal 129 is respectively arranged in the cell layer 100 mounted in the cell stack 10, 60.According to FIG. 3, the two seals 129 of a cell frame 120 seal an anode-side or cathode-side electrode space 12 / 13, 62 / 63 of the cell stack 10, 60 radially Rr outwards on the one hand with respect to a bipolar plate 110 and on the other hand with respect to the membrane 130. Furthermore, the seals 129 of two cell frames 120 directly adjacent to one another via the membrane 130 can be arranged offset to one another in the radial direction Rr.According to FIGS. 4 and 5, the two seals 129 seal off both the anode-side and the cathode-side electrode spaces 12, 13; 62, 63 of the cell stack 10, 60 from the two bipolar plates 110 toward the outside in the radial direction Rr. The function of the seals toward the membrane 130 is realized by fastening the membrane 130 in the cell frame 120, wherein two seals 129 and their seal grooves 128 are omitted.The cell layer 100 may have a fluid transport structure 140 (FIG. 3 ) or two fluid transport structures 140 (FIGS. 4 and 5 ), wherein the respective fluid transport structure 140 is configured in the cell stack 10, 60 in an anode-side and / or a cathode-side electrode space 12 / 13, 62 / 63 of the cell layer 100 and accordingly forms an anode-side and / or cathode-side fluid transport structure 140. In this case, the relevant fluid transport structure 140 is arranged on a large-area side of the membrane 130 within the cell frame 120. A respective fluid transport structure 140, 142 may be formed as a porous transport layer 142 or a gas diffusion layer 144. Other fluid transport structures 140 (see above) are of course applicable.A cross section (cf. FIGS. 3 to 5 ) of the cell frame 120 is not formed homogeneously according to the invention, but rather an inner cell frame core 121 of the cell frame 120 is formed more rigid than an outer cell frame jacket 122 of the cell frame 120 at least partially surrounding the latter (cf. above). Here, the cell frame core 121 is at least partially or completely embedded in the cell frame jacket 122. In particular, the cell frame core 121 comprises a different material than the cell frame jacket 122, wherein the cell frame core 121 is preferably formed from a (very) stiff material (cf. above), and the cell frame jacket 122 is preferably formed from a possibly stiff plastic, such as a thermoplastic, a thermosetting plastic, etc.In this case, the entire cell frame core 121 alone can be formed more rigid than the cell frame jacket 122 alone. Furthermore, the entire (comparatively small) cell frame core 121 can be formed more rigid in isolation than a (comparatively large) solid cell frame made of plastic, also made of one of the aforementioned plastics, wherein a space for the cell frame core 121 is substituted by a material of the cell frame jacket 122 for the solid cell frame. This is applicable to all embodiments of the invention.Cell frame core 121 is preferably configured centrally in cell frame jacket 122 in axial direction Ar and / or in radial direction Rr of cell layer 100 (FIG. 3, with restriction also FIGS. 4 and 5 ) and / or coaxially (FIGS. 3 to 5 ). In this case, a radial main direction of extent of the cell frame core 121 is set up substantially parallel to the bipolar plates 110 in the cell stack 10, 60. A simple cross section of the cell frame core 121 is preferably rectangular (FIGS. 3 and 4 ), wherein other cross-sectional shapes (FIG. 5, cf. below) can of course also be used if appropriate. - The cell frame 120 can have a single, preferably completely encircling cell frame core 121 (cf. FIGS. 3 and 4 ) or else a multipart, preferably completely encircling cell frame core 121 (cf. FIG. 5 ).The cell frame 120 has (vertical / horizontal) medium passage recesses 105, which pass through its cell frame jacket 122 and preferably also its cell frame core 121. Furthermore, the cell frame jacket 122 can have (horizontal / vertical) medium channels 125 which, starting from the medium passage recesses 105, open into a relevant electrode space 12 / 13, 62 / 63 which is bounded by the cell frame 120 in the circumferential direction Ur. That is, the electrode space 12 / 13, 62 / 63 is in fluid communication with the medium passage recesses 105. In this case, the media channels 125 can be configured, for example, as grooves 125 in the cell frame jacket 122.The medium passage recesses 105 and the medium channels 125 serve for supplying and / or disposing of the electrode space 12 / 13, 62 / 63 with / from a medium 3 / 5, 53 / 54 / 56. - FOR EXAMPLE in the case of an electrolysis cell stack 60, the medium passage recesses 105 are designed as chimney(s) 105 and the medium channels 125 as delta channels 125. In this case, medium passage recesses 105 and medium channels 125 supply and / or dispose of the electrode space 62 / 63 with the supply medium 53, from the disposal medium 54 or from the product medium 56.In alternative embodiments, a single cell layer 100 can comprise two cell frames 120 and the membrane 130 arranged therebetween, wherein a fluid transport structure 140 can be arranged in one or in both cell frames 120 (see Pos: (100) in FIG. 3 ).Further, in alternative embodiments, see FIG. 4, a single cell layer 100 may comprise a single cell frame 120 having a single cell frame shell 122 (of course, including. Cell frame core 121) for both electrode spaces 12, 13 / 62, 63. In this case, the membrane 130 can be provided or fixed essentially centrally within the cell frame jacket 122 in the axial direction Ar, for example on a terrace-shaped inner collar protruding inward there in the radial direction Rr, in particular in a fluid-tight manner.A further alternative embodiment is shown in FIG. 5. Here, the cell frame core 121 of the embodiment according to FIG. 4 is formed in multiple parts, in the present case in four parts in cross section. Another division, in particular a division into two, a division into three, etc., is of course applicable. In this case, the parts or layers of the multipart cell frame core 121 can be configured in a staggered manner in the radial direction Rr in the cell frame jacket 122. Furthermore, the parts of the cell frame core 121 can be configured in the cell frame jacket 122 in such a way that the medium passage recesses 105 thereof lead past the cell frame core 121, i.e. are configured only in the cell frame jacket 122. Alternatively, the medium through-openings 105 can of course also lead through the cell frame core 121.The embodiment according to FIG. 5 is of course also applicable to embodiments according to FIG. 3. In this case, it is possible in particular to deposit the parts of the cell frame core 121 in the radial direction Rr with respect to at least one sealing groove 128. - Furthermore, the cell layer 100 comprising one (FIGS. 3 to 5 ) or two cell frames 120 (FIG. 3 ) can comprise at least one polar plate 110, wherein the polar plate 110 can be formed in particular as a bipolar plate 110 or else as a monopolar plate 110 (not illustrated).The cell layer 100 is suitable in particular for high-pressure electrolysis. By using a cell frame core 121, in particular made of a metal (metal alloy), and a cell frame jacket 122, in particular made of a strip plastic, a desired strength can be achieved, wherein the cell frame core 121 can be isolated from a chemical environment (no contamination with DI water thus preventing ion washing out of the cell frame core 121 and therefore preventing a loss of strength). There remains also the possibility of placing seals 129. In addition, bracing forces of the cell stack 10, 60 can be transmitted well via the comparatively narrow plastic of the cell frame casings 122.

Claims

Cell layer (100) for an electrochemical cell stack (10, 60), in particular a fuel cell stack (10) or an electrolysis cell stack (60), comprising at least one cell frame (120), which extends circumferentially in the circumferential direction (Ur) of the cell layer (100), for the radial (Rr) liquid sealing of at least one electrode space (12 / 13, 62 / 63) of the cell stack (10, 60), characterized in that a representative volume element of a cell frame core (121) of the cell frame (120) is formed more rigid than an equally large representative volume element of a cell frame casing (122) of the cell frame (120), in which the cell frame core (121) is at least embedded.Cell layer (100) according to the preceding claim, characterized in that: • a mass density of the cell frame core (121) is greater than a mass density of the cell frame jacket (122), • a material of the cell frame core (121) is different from a material of the cell frame jacket (122), and / or • the cell frame core (121) comprises a metal or a metal alloy and / or the cell frame jacket (122) comprises a plastic.Cell layer (100) according to one of the preceding claims, characterized in that: • the cell frame core (121) of the cell frame jacket (122) is formed in one part or in multiple parts, • in a cross section of the cell frame (120), the cell frame jacket (122) does not surround the cell frame core (121) in its circumferential direction on all sides or only on one side, and / or • the cell frame core (121) is embedded in the cell frame jacket (122) on all sides.Cell layer (100) according to one of the preceding claims, characterized in that the cell frame jacket (122) has a sealing groove (128) for receiving a seal (128), wherein a material of the cell frame jacket (122) is present in the groove base, and / or the cell frame jacket (122) has in each case such a sealing groove (128) on both sides of the cell frame core (121) in the axial direction (Ar).Cell layer (100) according to one of the preceding claims, characterized in that the cell frame (120) has medium passage recesses (105), which pass through its cell frame jacket (122) and preferably its cell frame core (121), and / or the cell frame jacket (122) has medium channels (125), via which the medium passage recesses (105) and the electrode space (12 / 13, 62 / 63) are in fluid communication.Cell layer (100) according to one of the preceding claims, characterized in that the cell frame (120) radially (Rr) delimits a single electrode space (12 / 13 / 62 / 63) for the cell stack (10, 60), wherein a fluid transport structure (140, 142 / 144) is configured in the free space provided for this purpose in the cell layer (100), and / or a membrane (130) is configured in the cell layer (100) on a large-area side of the fluid transport structure (140, 142 / 144) of this cell frame (120).Cell layer (100) according to one of the preceding claims, characterized in that the cell layer (100) comprises two cell frames (120) and a membrane (130) arranged therebetween, wherein a fluid transport structure (140, 142 / 144) is arranged in neither, one or both cell frames (120).Cell layer (100) according to one of the preceding claims, characterized in that the cell frame (120) radially (Rr) delimits exactly two electrode spaces (12, 13 / 62, 63) for the cell stack (10, 60), wherein in each case a fluid transport structure (140, 140; 142, 144) is configured in the free spaces provided for this purpose in the cell layer (100), and / or a membrane (130) is configured in the cell layer (100) between the fluid transport structures (140, 140; 142, 144) of this cell frame (120).Cell layer (100) according to one of the preceding claims, characterized in that the cell layer (100) comprises a single cell frame (120) and a membrane (130) arranged therein substantially centrally in the axial direction (Ar), wherein a fluid transport structure (140, 142 / 144) is arranged on one side, on both sides or on no side of the membrane (130).Cell layer (100) according to one of the preceding claims, characterized in that: • the cell frame jacket (122) and / or the cell frame core (121) has or have a mainly or substantially rectangular cross section, • the cell layer (100) further comprises a membrane (130) and / or a bipolar plate (110), • the cell frame (120) is formed as an injection-molded part (120) with the cell frame core (121) as an insert part (121), and / or • the cell frame jacket (122) is formed as an integral, a materially one-piece or a one-piece cell frame jacket (122).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 electrolyser unit (51), having a multiplicity 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.Electrochemical cell stack (10, 60) according to the preceding claim, characterized in that in the cell stack (10, 60): • in each case two bipolar plates (110), an anode-side cell layer (100) having a fluid transport structure (140 / 141 / 142) arranged therein, a membrane and a cathode-side cell layer (100) having a fluid transport structure (140 / 142 / 141) arranged therein, together, and / or • the sealing grooves (128) of two cell frames (120) directly adjacent to one another with respect to a membrane (31) are arranged offset with respect to one another in the radial direction (Rr) in such a way that they do not have a radial (Rr) overlapping region, or • in each case two bipolar plates (110) clamp together a single cell layer (100) comprising a single cell frame (120), a membrane (130) and fluid transport structures (140, 140 / 141, 142) arranged on both sides of the membrane (130).Electrochemical unit (1, 51), in particular fuel cell unit (1) or electrolyser unit (51), or electrochemical system, in particular fuel cell system or electrolyser system, having at least one electrochemical cell stack (10, 60) and a control unit for actuating and / or adjusting operation of the cell stack (10, 60), characterized in that cell layers (100) of the cell stack (10, 60) are designed according to one of the preceding claims and / or the cell stack (10, 60) is designed according to one of the preceding claims.

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