Spacer for a solid oxide electrochemical device, solid oxide electrochemical device comprising such a spacer, and solid oxide electrochemical system comprising such devices

Abstract

The invention relates to a spacer for a solid oxide electrochemical device (200), said device (200) comprising: at least one interconnector (102, 104), a solid oxide electrochemical cell (106) disposed between said interconnector (102, 104) and another interconnector (102, 104), and said spacer (202), disposed between said interconnectors (102, 104), in particular, around said cell (106); characterized in that said spacer (202): comprises a layer, said main layer, made of a ceramic matrix composite material, said CMC material, or of a precursor of said CMC material, which is electrically insulating; and is partially or wholly gas-tight. It also relates to a solid oxide electrochemical device comprising such a spacer. Furthermore, it relates to a solid oxide electrochemical system comprising such electrochemical devices. See Figure 2a

Description

Title of the invention: Spacer for a solid oxide electrochemical device, solid oxide electrochemical device comprising such a spacer, and solid oxide electrochemical system comprising such devices

[0001] The present invention relates to a spacer for a solid oxide electrochemical device. It also relates to a solid oxide electrochemical device comprising such a spacer. Furthermore, it relates to a solid oxide electrochemical system comprising such devices.

[0002] The field of the invention is generally the field of solid oxide electrochemical systems, such as electrolyzers or fuel cells. Prior art

[0003] A solid oxide electrochemical system (SEOS), of the electrolyzer or fuel cell type, comprises a stack of unit devices. Each unit device in the stack comprises an electrically conductive interconnector and a solid oxide electrochemical cell disposed between said interconnector and another interconnector, for example, of an adjacent electrochemical device. Electrical continuity must be maintained between each interconnector and the cell, while direct electrical contact between said two interconnectors must be avoided to prevent short-circuiting the electrochemical cell. Furthermore, gas flow must be maintained between the cell and each interconnector, which necessitates gas-tightness between the interconnectors around the cell.

[0004] During operation, the stack is brought to a high operating temperature, for example, between 600°C and 850°C in the case of a solid oxide electrolyzer (SOE). Consequently, it is necessary that the components of the SEOS be resistant to these temperatures and have similar expansion behaviors, otherwise the SEOS will be degraded. Furthermore, the SEOS operates in a humid, redox atmosphere, which requires chemical compatibility of its component parts.

[0005] Due to these constraints, in current architectures, electrical insulation is provided by an electrical insulation layer placed between the interconnectors, which is generally made of a mica-based material. However, the mica insulation layer is mechanically fragile, making its manufacture and handling difficult, particularly when it is subjected to pressure during stack operation, for example in the case of solid oxide electrolyzers.

[0006] In certain embodiments, gas tightness can be ensured by a multitude of sealing beads, generally made of glass, deposited between the parts forming the electrochemical device. The deposition of these sealing beads is time-consuming, making the manufacture of the SEOS time-consuming and costly. Furthermore, a defect in these sealing beads will have significant consequences on the performance of the SEOS, and may even lead to its degradation.

[0007] Moreover, the use of the insulation layer combined with the multiple sealing cords makes the architecture of the SEOS complex, making its manufacture and assembly costly and time-consuming, not to mention the intrinsic fragility due to the insulation layer made of mica.

[0008] One object of the present invention is to remedy at least one of the aforementioned drawbacks.

[0009] Another object of the invention is to provide a solution to simplify the architecture of SEOS.

[0010] Another objective of the invention is to offer a solution making the manufacture of SEOS less time-consuming and / or less expensive. Description of the invention

[0011] The invention proposes to achieve at least one of the aforementioned objectives by means of a spacer for a solid oxide electrochemical device, said device comprising: - at least one interconnector (102,104), - a solid oxide electrochemical cell (106) disposed between said interconnector (102,104) and another interconnector, and - said spacer, arranged between said interconnectors (102,104), in particular, around said cell; characterized in that said spacer (202): - comprises a layer, called the main layer, made of a ceramic matrix composite material, called CMC material, or of an electrically insulating precursor of said CMC material; - is partially, or totally, gas-tight.

[0012] Thus, the invention proposes the use of a gas-tight spacer comprising a main layer made of a CMC material, or a CMC precursor, which is electrically insulating. Electrical insulation between the interconnectors and gas tightness between the interconnectors are thus directly ensured by the spacer. In other words, in the electrochemical device, these two functions are performed by a single component, namely the spacer comprising a main layer of a CMC material, thereby simplifying the architecture. of the electrochemical device and therefore of the SEOS, making the manufacture of the SEOS less time-consuming and less expensive.

[0013] Furthermore, the spacer comprising the main layer made of CMC material exhibits superior mechanical strength compared to a spacer made of a single layer of mica, allowing for simpler handling and manufacturing. Thus, assembling the spacer with the other parts of the electrochemical device is easier, making the manufacture of the electrochemical device, and therefore of the SEOS, simpler, less time-consuming, and less expensive.

[0014] By "gas-tight" or "sealed," we mean a barrier to the passage of gas, preventing the passage of gases. In the present invention, it is considered that each sealed part of the spacer is gas-tight when it opposes the passage of gas, and in particular the passage of hydrogen, such that the quantity of gas passing through said sealed part is less than or equal to 6.106 g / minute / cm2, in particular to 3.106 g / minute / cm2, and even more particularly to 6.107 g / minute / cm2: - at a temperature between 600°C and 850°C; and - when the pressure difference on either side of said sealed part is less than or equal to 100 mbar.

[0015] In an electrochemical device, gas tightness means a tightness that prevents communication between the fluids present in the different zones of said electrochemical device and, in particular, a tightness between: - the two zones located on either side of the electrochemical cell; and - possibly a channel for supplying flux entering said electrochemical device; and - possibly an extraction channel for the outgoing flux of said electrochemical device. This seal must be sufficient to prevent the mixing of the different gas streams so as not to impair the operation of the electrochemical device, or to damage the electrochemical device itself. The spacer according to the invention can provide at least one of these seals.

[0016] Furthermore, by "gas-tight" or "tight," we mean tightness against the gases present in the electrochemical device, at least at the operating temperature of said device. In other words, the spacer must be tight against the gases present in the electrochemical device at least at the operating temperature of said electrochemical device. This tightness can be achieved with a material that is gas-tight at all temperatures. Alternatively, this tightness can be achieved with a material that is not initially gas-tight. to gases, for example at room temperature, but which becomes gas-tight at the operating temperature of the electrochemical device. For example, glass particles may not be gas-tight at room temperature, but give rise to a gas-tight sintered glass when these particles are heated above the glass transition temperature of the glass. As will be described later, gas tightness can be achieved in different ways, according to one of the variants described below.

[0017] By "electrically insulating," we mean electrical insulation at least at the operating temperature of the electrochemical device. In other words, the spacer must be electrically insulating at least at the operating temperature of said electrochemical device. This electrical insulation can be achieved with a material that is electrically insulating at all temperatures. Alternatively, this electrical insulation can be achieved with a material that is not initially electrically insulating, for example at room temperature, but which becomes electrically insulating at the operating temperature of the electrochemical device.

[0018] Furthermore, by "electrically insulating" is meant an electrical conductivity below a predefined limit, given that any material can conduct electricity to some extent.

[0019] By "ceramic matrix composite material," or "CMC material," or "CMC," we conventionally mean a ceramic composed of at least one ceramic textile stiffened by a ceramic matrix. By "precursor of a ceramic matrix composite material," or "precursor of a CMC material," or "precursor of CMC," we mean a material capable of providing said CMC after in situ temperature exposure in the solid oxide electrochemical device. For example, a material consisting of at least one ceramic textile incorporated into a glass particle-based matrix is ​​a precursor of CMC when said matrix stiffens said textile after exposure to a temperature above the glass transition temperature of said glass.

[0020] A “textile” is an assembly of fibers, possibly a yarn, in particular an assembly of yarns.

[0021] A "fiber" is a filament whose length is greater than 5 times its equivalent diameter. The "equivalent diameter" of a fiber is the diameter of a disk with the same area as its cross-section at half its length.

[0022] In a textile, the fibers may be assembled in a disordered manner, as in felt or paper, or along one or more preferred directions, preferably in the form of yarns, themselves preferably in the form of one or more fabrics. A yarn in a textile may be: - a "single yarn", which is an assembly of fibers which, in cross-section, comprises more than 10, and preferably fewer than 500,000 fibers, and whose length is greater than 5 times the diameter; or - an "assembled wire", which is an assembly of simple wires which, in cross-section, preferably comprises more than 2 and preferably less than 500 simple wires.

[0023] A textile can be, in particular: - an organized structure of fibers and / or threads, simple or assembled, including a knit or fabric, or - a random structure of fibers, and / or yarns, simple or assembled, for example a veil, and / or of fibers not incorporated in the form of yarns, said random structure being able to be for example a paper or a felt, a random structure not being preferred.

[0024] A "fabric" consists of a network of parallel warp yarns and weft yarns passing transversely through said network.

[0025] A "knit" consists of a network of threads in the form of loops.

[0026] A "net" consists of a set of parallel wires.

[0027] By "ceramic" we mean a product which is neither metallic nor organic. In the context of the present invention, carbon is considered a ceramic product. Glass and glass-ceramic are also considered ceramic products in the context of this application.

[0028] By “sintered glass” is meant a monolithic compound of said glass, obtained after heat treatment at a temperature above the glass transition temperature of said glass and cooling.

[0029] The term "glass-ceramic material" or "glass-ceramic" refers to a microcrystalline compound obtained by controlled crystallization of a glass-ceramic precursor glass. The controlled crystallization of a precursor glass (conventionally in the solid state) is typically carried out in a step that follows, immediately or not, the step of obtaining said precursor glass. Controlled crystallization is usually called "crystallization heat treatment".

[0030] Glass-ceramic materials are composed of fine crystallizations (microcrystallizations), generally with an average size of less than 1 pm, immersed in a residual glassy phase. The amount of glassy phase does not limit the invention. In particular, it can be very small.

[0031] Obtaining a glass-ceramic material therefore requires two steps, namely the manufacture of a precursor glass and then the crystallization of this glass.

[0032] Products manufactured by melt-cooling which, during their manufacture, do not pass through a stage in which they are in a glassy state are therefore not glass-ceramic materials. Fused corundum, fused alumina, fused spinels, fused magnesia, fused mullite, fused mullite-zirconia and fused aluminum titanate, possibly doped, are not, in particular, glass-ceramic materials.

[0033] The spacer, made of a CMC material, or CMC precursor, is gas-tight and electrically insulating.

[0034] The manufacture of a CMC, or a CMC precursor, can be carried out by any conventional method, and in particular includes the following steps: - i) disposition, on or in a textile, of a slip capable of forming a ceramic matrix after consolidation; - ii) before or after step i), shaping of the textile; - iii) optionally drying so as to obtain at the end of step i), ii) or iii), a precursor of CMC; - iv) consolidation of said CMC precursor by heat treatment, preferably by sintering, so as to form the matrix and obtain the CMC.

[0035] In step i), the textile may in particular have the form of a sheet, for example a sheet made up of yarns extending substantially parallel to each other (said yarns being called "unidirectional yarns"), a knit, a fabric (i.e. a woven textile) or a stack of one or more sheets and / or knits and / or fabrics.

[0036] The textile may preferably be in the form of a felt or a fabric or a layer or a stack of felt(s) and / or layer(s) and / or fabric(s). The stack of fabrics and / or layers may be arranged so that the threads of the different fabrics or layers all extend substantially in the same direction, or in 2, 3, 4, 5 or 6 different directions, depending in particular on the mechanical properties required.

[0037] Preferably, at least some of, preferably all of, the textile fibers possibly assembled in the form of single yarns and / or assembled, may be fibers comprising more than 95%, preferably more than 97%, preferably more than 98%, preferably more than 99%, preferably more than 99.5% by mass of oxides.

[0038] Preferably, all the fibers can have the same composition.

[0039] The placement of the slip in the textile can in particular be carried out for example by impregnation.

[0040] Stacking can be achieved by pressing, or under vacuum, preferably after impregnation.

[0041] The manufacture of slip is well known to those skilled in the art. Slip is classically a suspension, for example of an aqueous base or an organic solvent, containing: - ceramic particles and / or ceramic particle precursors, i.e., compounds that transform into ceramic particles during the manufacture of the CMC or the CMC precursor, particularly during sintering; and - optionally dispersants, plasticizers, lubricants, and / or binders, preferably temporary.

[0042] The composition of the slip, the size distribution of the ceramic particles or ceramic precursors, and the mineral content of the slip are adapted to the type of fiber and the shaping technique. For example, the slip can be deposited on or within the textile, particularly by direct lamination, infusion, injection, infiltration, or deposition, under atmospheric pressure or higher pressure or vacuum, at ambient temperature or higher temperature.

[0043] Preferably, the ceramic particles can be particles comprising more than 95%, preferably more than 97%, preferably more than 98%, preferably more than 99%, preferably more than 99.5% by mass of oxides.

[0044] In step ii), the resulting textile, preferably impregnated with the slip, is shaped. The desired shape is preferably the final shape of the CMC or the CMC precursor. In one embodiment, however, the shape can be modified after the matrix has hardened, for example by machining or deformation.

[0045] In step iii), which is optional, a drying process is carried out. A person skilled in the art knows how to adjust the parameters of this step.

[0046] At the end of step i), ii) or iii), a CMC precursor is obtained.

[0047] In step iv), consolidation is carried out by heat treatment, preferably by sintering.

[0048] A person skilled in the art knows how to adjust the parameters of the process chosen for manufacturing the CMC precursor, and in particular how to determine the particle size of the raw materials, the moisture content during shaping, and the temperature of the optional drying step. A person skilled in the art also knows how to adjust the heat treatment temperature and the holding time at that temperature during consolidation.

[0049] Preferably, the CMC may also exhibit one or more of the following optional characteristics, or the CMC precursor may allow obtaining a CMC exhibiting one or more of the following optional characteristics: - CMC can be made up of oxides for more than 90% of its mass, preferably for more than 95% of its mass, preferably for more than 98% of its mass, preferably for more than 99% of its mass, preferably for more than 99.5% of its mass; CMC may have a total content (SiO2+ Al2O3 + ZrO2 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3 + P2O5 + SrO + La2O3 + Y2O3 + ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides; CMC may have an Al2O3 content greater than 80%, preferably greater than 85%, preferably greater than 90%, preferably greater than 95%, as a percentage by mass on the basis of oxides; CMC may have a SiO2 content greater than 80%, preferably greater than 85%, preferably greater than 90%, preferably greater than 95%, as a percentage by mass on the basis of oxides; CMC can contain more than 20% and less than 80% by volume of fibers, the remainder being made up of the matrix; CMC fibers can be composed of more than 90%, preferably more than 95%, preferably more than 99% oxides, by mass percentage; CMC fibers may have a total content (SiO2+Al2O3) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass; CMC fibers may have a SiO2 content greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, preferably greater than 95%, preferably greater than 99%, as a percentage by mass; CMC fibers may have an A12O3 content greater than 80%, preferably greater than 85%, preferably greater than 90%, preferably greater than 95%, preferably greater than 99%, as a percentage by mass; CMC fibers can be mullite fibers; all CMC fibers can have essentially the same chemical composition; CMC fibers can be arranged into the form of a fabric; the CMC matrix can be composed of more than 90%, preferably more than 95%, preferably more than 99% oxides, by mass percentage; the CMC matrix may include A12O3 and / or SiO2; - the CMC matrix may have a total content (SiO2 + Al2O3 + ZrO2 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3 + P2O5 + SrO + La2O3 + Y2O3 + ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides in the matrix.

[0050] According to embodiments, the spacer may include, on part or all of the main layer, a gas-tight layer made of a sealing material.

[0051] In this case, the spacer can be made of a CMC material, or a precursor of such a CMC material, which can be either gas-tight, not gas-tight, or partially gas-tight.

[0052] This allows for greater freedom in the choice of sealing material, and / or the CMC material, or the CMC material precursor, but above all, it allows for adapting the gas tightness to different temperatures, and more generally to different operating conditions of the electrochemical device. For example, for an electrochemical device operating at a temperature of 600°C to 850°C, the sealing material can be chosen to be gas-tight at these temperatures. This sealing material can be different for a device operating at another temperature, for example, 150°C. The same reasoning applies to the gases involved in the sealing, which can differ from one device to another. Thus, by using the same CMC material, or the same CMC material precursor, for the spacer, it is possible to adapt it to different devices.

[0053] This embodiment also has the advantage of obtaining a seal for the spacer in a quick and uncomplicated manner.

[0054] Preferably, in these embodiments, the CMC material, or said CMC material precursor, may have one or more of the optional characteristics described above.

[0055] The sealing material can be deposited, in the form of a layer, on at least a portion of at least one face of the main layer. In particular, a layer of sealing material can be deposited on each face of the main layer, depending on the architecture of the electrochemical device.

[0056] The application of said sealing material layer can be carried out using any technique known to a person skilled in the art.

[0057] The sealing material layer can be deposited over substantially all of at least one face of the main layer. The sealing layer can also be deposited over only a portion of the surface of the main layer, for example in the form of one or more beads, said portion of the surface being determined in such a way as to ensure sealing within the electrochemical device, as defined above, according to its architecture.

[0058] The sealing material layer can be produced using any technique known to a person skilled in the art.

[0059] Preferably, the sealing material layer may have a thickness less than or equal to 0.3 mm, in particular less than or equal to 0.2 mm, in particular less than or equal to 0.15 mm, in particular less than or equal to 0.10 mm, and even more particularly less than or equal to 0.05 mm.

[0060] Depending on embodiments, the sealing material may be, or may comprise: glass particles, in particular glass particles used as precursors for glass-ceramics; or a layer of sintered glass, and in particular a layer of glass precursor for glass-ceramics; or a layer of glass-ceramic.

[0061] In a first embodiment, referred to as "mode 1", the sealing material may be, or may comprise, glass particles. Preferably, the mass complement to the glass particles comprises at least one product selected from: an organic solvent, water, and an organic product, preferably a binder and / or a plasticizer and / or a dispersing. Preferably, the mass quantity of glass particles in the sealing material can be greater than 60%, preferably greater than 70%, and preferably less than 95%, after drying in air at 20°C for 10 hours.

[0062] In mode 1, the layer containing glass particles undergoes heat treatment at a temperature above the glass transition temperature of the glass, preferably when the spacer is placed in the electrochemical device. If the glass transition temperature of the glass is higher than the operating temperature of the electrochemical device, said device can be momentarily heated above the glass transition temperature before the temperature is subsequently lowered to the operating temperature.

[0063] Preferably in this mode 1, the glass can be a precursor glass for glass-ceramics, that is to say a glass suitable for producing a glass-ceramic by means of an appropriate heat treatment.

[0064] Preferably, said glass precursor of glass-ceramic may have a total content of (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3 + P2O5+ (SrO + La2O3 + Y2O3 + ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a mass percentage based on the oxides. Preferably, said glass precursor for glass-ceramics may also have a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a mass percentage based on the oxides.

[0065] Preferably, when the glass is a precursor glass for glass-ceramics, the layer containing glass particles conventionally undergoes heat treatment at a temperature suitable for generating crystallization, for example, when the spacer is placed in the electrochemical device. If said temperature is higher than the operating temperature of the electrochemical device, said device can be momentarily brought to said temperature before the temperature is subsequently reduced to the operating temperature. Depending on the precursor glass for glass-ceramics, a person skilled in the art knows how to determine the conditions of the heat treatment, in particular the temperature and the holding time at that temperature to generate crystallization, as described, for example, in document WO 2014 / 160948 A1.

[0066] In a second embodiment, referred to as "Mode 2", the sealing material may be, or may comprise, a layer of sintered glass. Preferably, the sealing material may be a layer of sintered glass. Those skilled in the art know how to produce said layer of sintered glass. In particular, it may be obtained by depositing glass particles onto the surface of the spacer followed by heat treatment at a temperature above the glass transition temperature of the glass.

[0067] In this mode 2, the sintered glass layer undergoes heat treatment at a temperature above the glass transition temperature of the glass, preferably when the spacer is placed in the electrochemical device. If the glass transition temperature of the glass is higher than the operating temperature of the electrochemical device, said device can be momentarily brought to a temperature above the glass transition temperature before the temperature is subsequently reduced to the operating temperature.

[0068] Preferably in this mode 2, the glass can be a precursor glass for glass-ceramics, that is to say a glass suitable for producing a glass-ceramic by means of an appropriate heat treatment.

[0069] Preferably, said glass precursor of glass-ceramic may have a total content of (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3 + P2O5+ (SrO + La2O3 + Y2O3 + ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a mass percentage based on the oxides. Preferably, said glass precursor for glass-ceramics may also have a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a mass percentage based on the oxides.

[0070] Preferably, when the glass can be a precursor glass for glass-ceramics, the sintered glass layer can conventionally undergo heat treatment at a temperature suitable for generating crystallizations, for example, when the spacer is placed in the electrochemical device. If said temperature is higher than the operating temperature of the electrochemical device, said device can be momentarily brought to said temperature before the temperature is subsequently reduced to the operating temperature. Depending on the precursor glass for glass-ceramics, a person skilled in the art knows how to determine the conditions of the heat treatment, in particular the temperature and the holding time at that temperature to generate crystallizations, as described, for example, in document WO 2014 / 160948 A1.

[0071] In a third embodiment, referred to as "mode 3", the sealing material layer may be, or may include, a glass-ceramic layer.

[0072] Preferably, the glass-ceramic layer can have a total content (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3+ P2O5+ SrO + La2O3+ Y2O 3+ ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides. Preferably, the glass-ceramic layer may also have a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a percentage by mass on the basis of oxides.

[0073] Preferably in this mode 3, the glass-ceramic layer undergoes heat treatment at a temperature above the glass transition temperature of its residual glass phase when the spacer is placed in the electrochemical device. If the glass transition temperature of the residual glass phase is above the operating temperature of the electrochemical device, said device can be momentarily brought to a temperature above said glass transition temperature before the temperature is then decreased to the operating temperature.

[0074] According to an alternative embodiment, referred to as variant 1, the CMC material may comprise a matrix that is not gas-tight, or be a precursor of such a CMC material. In this case, the spacer comprises a sealing layer deposited over the entire main layer, such as the sealing layer described above.

[0075] This embodiment variant allows greater freedom in the choice of CMC material, or precursor of such CMC material, to produce the spacer.

[0076] Preferably, in this variant 1, the CMC material, or the precursor of such a CMC material, may have one or more of the optional characteristics described above.

[0077] According to an alternative embodiment, referred to as variant 2, the CMC material comprises a deep-sealing matrix, on only part of the main layer, or is a precursor of such a CMC material.

[0078] In this case, the main layer, and therefore the spacer, provides a deep seal only over a portion of said main layer, and thus of said spacer. In other words, the spacer will be gas-tight only in certain parts. This embodiment has the advantage of providing a more robust seal that is not susceptible to surface damage, without requiring a deep seal over the entire spacer.

[0079] As explained above, the function of gas tightness is to prevent the mixing of gas flows circulating in different areas of the electrochemical device, for example: - in the two zones located on either side of the electrochemical cell, and - possibly in one / each gas flow supply channel entering the electrochemical device; and - possibly in one / each gas flow outlet channel from the electrochemical device.

[0080] The spacer may be gas-tight throughout, but only in certain portions of said spacer located between the different zones through which gas flows, so as to ensure gas tightness between these different zones. These gas-tight portions of the spacer may be defined by a sealing pattern. The sealing pattern may include: - a portion extending between the two zones of the electrochemical device located on either side of the electrochemical cell, in particular in a direction parallel to the plane formed by the spacer; and / or - a portion extending between one / each gas supply channel entering the electrochemical device and the rest of the spacer, in particular in a direction perpendicular to the plane formed by the spacer; and / or - a part extending between one / each gas outlet channel of the electrochemical device and the rest of the spacer, in particular in a direction perpendicular to the plane formed by the spacer.

[0081] Generally, the sealing pattern is defined to ensure the sealing of at least one area of ​​the electrochemical device through which a gas flow circulates, with respect to: - at least one other area of ​​the electrochemical device through which a gaseous flow circulates; and - possibly the outside.

[0082] In this variant 2, the CMC material or CMC precursor may have one or more of the optional characteristics described above, for the parts of the spacer that are not gas-tight.

[0083] In an embodiment of this variant 2, referred to as "variant 2.1", for at least one, and in particular each, sealing portion of the spacer, the CMC precursor matrix may be formed of, or may comprise, glass particles. Preferably, the mass complement to the glass particles may comprise at least one product selected from an organic solvent, water, and an organic product, preferably a binder and / or a plasticizer and / or a dispersant. Preferably, in the portion of the spacer capable of becoming sealing, the CMC precursor matrix may comprise a mass quantity of glass particles greater than 60%, preferably greater than 70%, and preferably less than 95%, after drying in air at 20°C for 10 hours.

[0084] In this variant 2.1, the CMC precursor undergoes heat treatment at a temperature above the glass transition temperature of the glass, preferably when the spacer is placed in the electrochemical device. If the glass transition temperature of the glass is higher than the operating temperature of the electrochemical device, said device can be momentarily raised to a temperature above the glass transition temperature before the temperature is subsequently lowered to the operating temperature.

[0085] Preferably, in variant 2.1, the glass can be a precursor glass for glass-ceramics, i.e. a glass suitable for producing a glass-ceramic by means of an appropriate heat treatment.

[0086] Preferably, said glass precursor of glass-ceramic may have a total content (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3 + P2O5 + SrO + La2O3 + Y2O3 + ZnO) greater than 70%, preferably greater than 75%, of preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of oxides. Preferably, said glass precursor of glass-ceramic also has a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a percentage by mass on the basis of oxides.

[0087] Preferably, when the glass is a precursor glass for glass-ceramics, the CMC precursor conventionally undergoes heat treatment at a temperature suitable for generating crystallizations in said glass, preferably when the spacer is placed in the electrochemical device. If said temperature is higher than the operating temperature of the electrochemical device, said device can be momentarily brought to said temperature before the temperature is subsequently reduced to the operating temperature. Depending on the glass-ceramic precursor glass, a person skilled in the art knows how to determine the conditions of the heat treatment, in particular the temperature and the holding time at that temperature to generate crystallizations, as described, for example, in document WO 2014 / 160948 A1.

[0088] In an embodiment of variant 2, referred to as "variant 2.2", for at least one, in particular each, sealed portion of the spacer, the matrix of the CMC or the CMC precursor may be, or may comprise, sintered glass. Those skilled in the art know how to produce said matrix from sintered glass. It may, in particular, be obtained using glass particles heat-treated at a temperature above the glass transition temperature of the glass.

[0089] Preferably, in variant 2.2, the glass can be a precursor glass for glass-ceramics, i.e. a glass suitable for producing a glass-ceramic by means of an appropriate heat treatment.

[0090] Preferably, said glass precursor of glass-ceramic may have a total content (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3+ P2O5+ SrO + La2O3+ Y2O3+ ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides. Preferably, said glass precursor of glass-ceramic also has a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a percentage by mass on the basis of oxides.

[0091] Preferably, when the glass is a precursor glass for glass-ceramics, the CMC or the CMC precursor conventionally undergoes heat treatment at a temperature suitable for generating crystallizations in said glass, preferably when the spacer is placed in the electrochemical device. If said temperature is higher than the operating temperature of the electrochemical device, said device can be momentarily brought to said temperature before the temperature is subsequently reduced to the operating temperature. Depending on the precursor glass for glass-ceramics, a person skilled in the art knows how to determine the conditions of the heat treatment, in particular the temperature and the holding time at that temperature to generate crystallizations, as described, for example, in document WO 2014 / 160948 A1.

[0092] In an embodiment of variant 2, referred to as "variant 2.3", for at least one, in particular each, sealed part of the spacer, the matrix of the CMC or of the precursor of the CMC may be, or may comprise, a glass-ceramic.

[0093] Preferably, said glass-ceramic may have a total content (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3+ P2O5+ SrO + La2O3+ Y2O3+ ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides. Preferably, said glass-ceramic may have a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a percentage by mass on the basis of oxides.

[0094] The spacer according to variant 2 can for example be manufactured using an impregnation technique employing masking.

[0095] The portion of the fibers intended to receive the gas-tight matrix can be masked with a material, for example an organic material, so as to reproduce the sealing pattern. The fibers can then be impregnated with a non-gas-tight matrix. The masking is then removed, for example, by means of a thermal or chemical treatment. The portions of the fibers that are accessible again after the removal of the masking material are then impregnated with a gas-tight matrix, in particular as described in variants 2.1, 2.2, or 2.3.

[0096] In this variant 2, the spacer may not include a sealing layer. Indeed, in this case, the use of a sealing material is not necessary, as the sealing of the spacer parts is primarily ensured by the matrix of the CMC material. Preferably, the spacer consists of the main layer made of said CMC material or a precursor of said CMC material.

[0097] Alternatively, the spacer may include, preferably consists of, a sealing layer deposited on the main layer: - over the entirety of said main layer; - or only on a part of said main layer, for example at the level of at least a part of said main layer which is not watertight in depth.

[0098] The sealing layer can be that described above, in particular a sealing layer obtained according to one of the modes 1-3 described above.

[0099] In other words, variant 2 of the CMC material can be combined with embodiments 1-3 of the sealing layer.

[0100] According to an embodiment, referred to as variant 3, the CMC material may comprise a deep, watertight matrix over the entire main layer, or be a precursor of such a CMC material.

[0101] In other words, the main layer, and therefore the spacer, can be gas-tight in depth, or in its thickness, for all parts of said main layer, and therefore of the spacer.

[0102] In this variant 3, the spacer can be made of a CMC material whose matrix is ​​gas-tight over its entire depth, or of a precursor of such a CMC material.

[0103] In this variant 3, the use of a sealing material is therefore not necessary, but is not excluded either, the sealing being ensured by the matrix of the CMC, in all parts of said spacer.

[0104] This variant 3 has the advantage of a more robust seal that is not susceptible to surface damage. Furthermore, since the gas seal is present on all parts of the spacer, its integration into the electrochemical device is simplified.

[0105] In an embodiment of variant 3, referred to as "variant 3.1", the matrix of the CMC precursor material may be formed of, or may comprise, glass particles. Preferably, the mass complement to the glass particles may comprise at least one product selected from an organic solvent, water, and an organic product, preferably a binder and / or a plasticizer and / or a dispersant. Preferably, the matrix of the CMC precursor may comprise a mass percentage of glass particles greater than 60%, preferably greater than 70%, and preferably less than 95%, after drying in air at 20°C for 10 hours.

[0106] In variant 3.1, the CMC precursor undergoes heat treatment at a temperature above the glass transition temperature of the glass, preferably when the spacer is placed in the electrochemical device. If the glass transition temperature of the glass is above the operating temperature of the electrochemical device, said device can momentarily be brought to a temperature above the glass transition temperature before the temperature is subsequently reduced to the operating temperature.

[0107] Preferably, in variant 3.1, the glass can be a precursor glass for glass-ceramics, i.e. a glass suitable for producing a glass-ceramic by means of an appropriate heat treatment.

[0108] Preferably, said glass precursor of glass-ceramic may have a total content (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3+ P2O5+ SrO + La2O3+ Y2O3+ ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides. Preferably, said glass precursor of glass-ceramic may have a total content (SiO2 + MgO + CaO + BaO + B2O 3+ SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a percentage by mass on the basis of oxides.

[0109] Preferably, when the glass is a glass-ceramic precursor glass, the CMC precursor conventionally undergoes heat treatment at a temperature suitable for generating crystallizations in said glass, preferably when the spacer is placed in the electrochemical device. If said temperature is higher than the operating temperature of the electrochemical device, said device can be temporarily brought to said temperature before the temperature is subsequently reduced to the operating temperature. Depending on the glass-ceramic precursor glass, a person skilled in the art knows how to determine the conditions of the heat treatment, in particular the temperature and the holding time at that temperature to generate crystallizations, as described, for example, in document WO 2014 / 160948 A1.

[0110] In an embodiment of variant 3, referred to as "variant 3.2", the matrix of the CMC or the CMC precursor may be, or may comprise, sintered glass. Those skilled in the art know how to produce said matrix from sintered glass. In particular, it may be obtained using glass particles heat-treated at a temperature above the glass transition temperature of the glass.

[0111] Preferably, in variant 3.2, the glass can be a precursor glass for glass-ceramics, i.e. a glass suitable for producing a glass-ceramic by means of an appropriate heat treatment.

[0112] Preferably, said glass precursor of glass-ceramic may have a total content of (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3 + P2O5 + SrO + (La2O3+ Y2O3+ ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a mass percentage based on the oxides. Preferably, said glass precursor of glass-ceramic may have a total content (SiO2 + MgO + CaO + BaO + B2O3+ SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a mass percentage based on the oxides.

[0113] Preferably, when the glass is a glass-ceramic precursor glass, the CMC or the CMC precursor conventionally undergoes heat treatment at a temperature suitable for generating crystallizations in said glass, preferably when the spacer is placed in the electrochemical device. If said temperature is higher than the operating temperature of the electrochemical device, said device can be momentarily brought to said temperature before the temperature is subsequently reduced to the operating temperature. Depending on the glass-ceramic precursor glass, a person skilled in the art knows how to determine the conditions of the heat treatment, in particular the temperature and the holding time at that temperature to generate crystallizations, as described, for example, in WO 2014 / 160948 A1.

[0114] In one embodiment of variant 3, referred to as "mode 3.3", the matrix of the CMC or the CMC precursor may be, or may comprise, a glass-ceramic.

[0115] Preferably, said glass-ceramic may have a total content (SiO2 + Al2O3 + Li2O + Na2O + K2O + MgO + CaO + BaO + B2O3+ P2O5+ SrO + La2O3+ Y2O3+ ZnO) greater than 70%, preferably greater than 75%, preferably greater than 80%, preferably greater than 85%, preferably greater than 90%, as a percentage by mass on the basis of the oxides. Preferably, said glass-ceramic may have a total content (SiO2 + MgO + CaO + BaO + B2O3 + SrO) greater than 24%, preferably greater than 30%, preferably greater than 35%, preferably greater than 40%, preferably greater than 45%, or even greater than 50%, or even greater than 55%, or even greater than 60%, or even greater than 65%, as a percentage by mass on the basis of oxides.

[0116] In variant 3, the spacer may not include a sealing layer. Indeed, in this case, the use of a sealing material is not necessary, as the spacer's seal is ensured by the matrix of the CMC material over its entire extent. Preferably, the spacer consists of the main layer made of said CMC material or a precursor of said CMC material.

[0117] Alternatively, in variant 3, the spacer may include, preferably consists of, a sealing layer deposited on the main layer: - over the entirety of said main layer; - or only on a part of said main layer, for example to reinforce the sealing of certain parts of said spacer.

[0118] The sealing layer can be that described above, in particular a sealing layer obtained according to one of the modes 1-3 described above.

[0119] In other words, variant 3 of the CMC material can be combined with embodiments 1-3 of the sealing layer.

[0120] The spacer can have any geometric shape depending on the architecture of the electrochemical device, and in particular the stack.

[0121] For example, the spacer may have a general round shape, or polygonal shape, for example a square shape, a rectangular shape, etc.

[0122] The spacer may have any other shape, simpler or more complex.

[0123] The spacer may be in the form of several parts.

[0124] Preferably, the spacer can be in the form of a single, monobloc piece. This simplifies handling of the spacer. Furthermore, its assembly in each electrochemical device within the stack is simpler and less time-consuming.

[0125] According to some embodiments, the spacer may include a central opening allowing: - the passage of gas to, or from, the electrochemical cell; and / or - an electrical contact between: • the electrochemical cell, and • one, or each, interconnector, or an electrical contact piece disposed between said electrochemical cell and said interconnector

[0126] This central opening can be of any shape.

[0127] This central opening can be of any size determined according to the size of the electrochemical cell and the architecture of the electrochemical device.

[0128] According to another aspect of the present invention, a solid oxide electrochemical device is proposed comprising: - at least one electrically conductive interconnector, - a solid oxide electrochemical cell disposed between said interconnector and another interconnector, and - a spacer according to the invention, arranged between said two interconnectors.

[0129] Such an electrochemical device has a simpler architecture and is easier to manufacture, while also being less time-consuming and less expensive. Electrical insulation and gas tightness between the interconnectors is ensured by the spacer, which is also easier to handle.

[0130] As mentioned above, the shape and dimensions of the spacer can be determined according to the architecture of the electrochemical device.

[0131] According to embodiments, the spacer may have a thickness greater than the thickness of the electrochemical cell.

[0132] This allows the electrochemical cell to be accommodated but also, optionally, one or more electrical contact elements between said electrochemical cell and the, or each, interconnector, without losing contact between the spacer and said at least one interconnector.

[0133] Different positionings can be imagined between the spacer and the electrochemical cell, depending on the architecture of the electrochemical device.

[0134] According to some embodiments, the electrochemical cell can be arranged on the spacer, above a central opening provided in said spacer. In this case, the central opening is smaller than the electrochemical cell and the cell is placed on the spacer on one of its faces.

[0135] For example, a thinner support lip can be provided on the spacer around the central opening, the same size as the cell or slightly larger than the cell size, so that the cell can be placed on said support lip. Of course, other embodiments are possible.

[0136] This embodiment has the advantage of facilitating, in addition to sealing between the interconnectors, sealing between the cell and the spacer.

[0137] According to an example of an embodiment, in this case, the cell can be fixed to the spacer, which can allow the cell and the spacer to be assembled before placing them in the electrochemical device.

[0138] According to embodiments, the electrochemical cell can be arranged inside a central opening provided in said spacer, in particular without physical contact with said spacer.

[0139] In this case, the cell is entirely surrounded by the spacer.

[0140] According to an example of an embodiment, in this case, the cell can be fixed to an interconnector of the electrochemical device, or to any other part of the electrochemical device, depending on the architecture of said electrochemical device.

[0141] According to another aspect of the same invention, a solid oxide electrochemical system is proposed comprising a stack of several electrochemical devices, at least one of which is an electrochemical device according to the invention.

[0142] Preferably, each electrochemical device in the system according to the invention is an electrochemical device according to the invention. The end electrochemical devices include an interconnector located on the stacking side: The other interconnector, that is, the interconnector located on the opposite side of the stack, corresponds to a connecting piece of the stack. This connecting piece is also called a "manifold".

[0143] According to embodiments, the electrochemical system according to the invention can be a solid oxide electrolyzer for the electrolysis of water vapor at high temperature, for example at a temperature between 600°C and 850°C

[0144] According to embodiments, the electrochemical system according to the invention can be a solid oxide fuel cell, in particular for the generation of electricity by oxidation of a gas, and in particular of H2.

[0145] Of course these examples are by no means limiting and the electrochemical system according to the invention can be of any type of electrochemical system. Description of the figures and methods of implementation

[0146] Other advantages and features will become apparent upon examination of the detailed description of non-limiting embodiments and the accompanying drawings, in which: - Fig. 1 is a schematic representation of a non-limiting example of a unitary electrochemical device of the prior art; - FIGURES 2a-2c are schematic representations of three variants of a non-limiting example embodiment of a unitary electrochemical device according to the invention; - FIGURES 3a and 3c are schematic representations of three variants of another non-limiting embodiment of a unitary electrochemical device according to the invention; - Figures 4a-4c are schematic representations of three variants of another non-limiting embodiment of a unitary electrochemical device according to the invention; and - Figure 5 is a schematic representation of an example implementation non-limiting of an electrochemical system according to the invention.

[0147] It is understood that the embodiments described below are in no way limiting. In particular, variants of the invention may be conceived comprising only a selection of the features described below, isolated from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection includes at least one preferably functional feature without structural details, or with only a portion of the structural details if that portion alone is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0148] In particular, all the variants and embodiments described are combinable with each other if there is no technical obstacle to this combination.

[0149] In the figures and in the rest of the description, elements common to several figures retain the same reference.

[0150] Fig. 1 is a schematic representation of a non-limiting example of an embodiment of an electrochemical device according to the prior art, in cross-section.

[0151] The electrochemical device 100 of [Fig.1] can, for example, be an electrochemical device for a solid oxide electrolyzer, SOE, or for a solid oxide fuel cell, SOFC, or for any other electrochemical system of the electrolyzer or fuel cell type.

[0152] The electrochemical device 100 includes an interconnector 102, intended to cooperate with a second interconnector 104, for example from another electrochemical device, similar or identical.

[0153] The electrochemical device 100 further includes an electrochemical cell 106 disposed between the interconnectors 102 and 104.

[0154] Each interconnector 102-104 is electrically conductive to supply the electrochemical cell 106 with electric current, for example in the case of an electrolyzer, or to capture an electric current generated at the electrochemical cell 106, for example in the case of a fuel cell.

[0155] The electrochemical cell 106 can be any type of electrochemical cell, in particular an electrochemical cell carrying out a redox reaction of compounds in a gas stream supplied to said electrochemical cell 106. For example, the electrochemical cell can be a cell of a solid oxide electrolyzer for decomposing water vapor molecules and producing a hydrogen-rich gas stream. For example, the electrochemical cell can be a cell of a solid oxide fuel cell for oxidizing hydrogen molecules with oxygen molecules to produce an electric current.

[0156] The electrochemical cell 106 can have any type of architecture. For example, the electrochemical cell can be composed of several layers of materials, one of these layers providing, among other things, a mechanical support function.

[0157] Optionally, the electrochemical device 100 may include an electrical contact layer (not shown) between the electrochemical cell 106 and the interconnector 102. Such an electrical contact layer may be made of a grid of an electrically conductive material, such as nickel, allowing the passage of the gas flow while ensuring an electrical contact between the interconnector 102 and the electrochemical cell 106.

[0158] Optionally, the electrochemical device 100 may include an electrical contact layer (not shown) between the electrochemical cell 106 and the interconnector 104. Such an electrical contact layer may be made in any possible form, for example in the form of an LSM (for "lanthanum strontium manganite") layer having gas circulation channels, thus allowing the passage of the gas flow while ensuring an electrical contact between the interconnector 104 and the electrochemical cell 106.

[0159] The electrochemical device 100 further includes a spacer 108 disposed between the interconnectors 102-104. This spacer 108 serves to provide electrical insulation between the interconnectors 102-104 so as not to short-circuit the electrochemical cell 106 electrically. Generally, this spacer 108 is made of a mica-based material, which is electrically insulating at the operating temperature of the electrochemical device, this temperature being, for example, 600°C-850°C, or even higher temperatures, for example in the case of a solid oxide electrolyzer, SOE.

[0160] In the example shown, the gas flow(s) is / are supplied to the electrochemical cell by an inlet channel, CE, and recovered from the electrochemical cell by an outlet channel, CS, each of the channels CE and CS passing through the interconnectors 102-104 and the spacer 108. One of the interconnectors 102-104 includes a passage, for example formed by channels provided in the thickness of said interconnector 102-104, allowing the gas flow to pass from the channel CE to the electrochemical cell 106. The other of the interconnectors 104-102 also includes a passage, for example formed by channels provided in the thickness of said interconnector 104-102, allowing the gas flow from the electrochemical cell 106 to be discharged to the channel CS.Following an example embodiment, the passage provided in one of the interconnectors 102-104 for the gas flow is arranged in a direction perpendicular to that of the passage provided in the other of the interconnectors 104-102. In the example shown, the circulation of the gas flow is indicated by dashed arrows.

[0161] However, the spacer made of a mica-based material, or a similar material, is not gas-tight. Therefore, multiple sealing gaskets 110 are provided in the electrochemical device 100 to achieve gas tightness between the interconnectors 102-104 and the electrochemical cell 106, so as to channel the gas flow(s) and direct the gas flow entering the electrochemical device 100 towards the electrochemical cell 106, and collect the gas flow from the electrochemical cell 106 in order to expel it from the electrochemical device 100. The installation of these sealing gaskets 114 is time-consuming and a sensitive operation because the slightest defect in the gasket will cause a leak directly impacting the operation of the electrochemical device 100, or even leading to degradation of the electrochemical device 100. These sealing gaskets 110 are generally made of sintered glass.

[0162] Moreover, and most importantly, mica is a fragile material that is difficult to work and handle. It is a source of fragility for the electrochemical device. This problem is exacerbated when the electrochemical device is compressed or pressurized due to the conditions under which the electrochemical reaction is carried out.

[0163] All of these elements mean that the architecture of the electrochemical device 100 of [Fig.1] is complex, not very robust, and time-consuming and expensive to produce.

[0164] The invention proposes to remedy at least one of these drawbacks, partially or totally.

[0165] Figures 2a-2c are schematic representations of three variants of a non-limiting example of an embodiment of an electrochemical device 200 according to the invention, according to a cross-sectional view.

[0166] Each of the variants of the device 200 shown in FIGURES 2a, 2b and 2c includes all the elements of the unit electrochemical device 100 of [Fig.1], except with regard to the differences indicated below.

[0167] The electrochemical device 200 can, for example, be an electrochemical device for a solid oxide electrolyzer, SOE, or for a solid oxide fuel cell, SOFC, or for any other electrochemical system of the electrolyzer or fuel cell type.

[0168] The electrochemical device 200 includes at least one of the two interconnectors 102 and 104, the electrochemical cell 106. The circulation of gas flows in the electrochemical device 200 is identical to that of the unitary electrochemical device 100 of [Fig.1].

[0169] The electrochemical device 200 comprises, in place of the spacer made of a mica-based material 108, a spacer 202 comprising a layer 204, referred to as the main layer, made of a ceramic matrix composite material, CMC material, which is electrically insulating. The spacer 202 is further gas-tight, either partially or entirely.

[0170] The spacer 202, made of CMC material, exhibits superior mechanical strength compared to a mica layer, allowing for simpler handling and manufacturing. Thus, assembling the spacer 202 with the other parts of the electrochemical device is easier, making the manufacture of the electrochemical device 200 simpler, less time-consuming, and less expensive.

[0171] Furthermore, the spacer 202 is gas-tight and electrically insulating. Thus, the electrical insulation between the interconnectors 102-104 and the gas-tightness between said interconnectors 102-104 are directly ensured by the spacer 202. In other words, in the electrochemical device 200, these two functions are performed by a single part, namely the spacer 202, which simplifies the architecture of the electrochemical device, making the manufacture of said electrochemical device less time-consuming and less expensive.

[0172] In all variants shown in FIGURES 2a-2c, the spacer 202 is made in one piece, monobloc.

[0173] The gas tightness of the spacer 202 can be achieved by one of the embodiments described above: - by the CMC material or the precursor of said CMC material used for the main layer 204, and / or - by a sealing layer deposited on the main layer. Following non-limiting examples, the gas tightness of spacer 202 can be achieved: - according to variant 1 of the CMC material or of the precursor of said CMC combined with a sealing layer in particular according to one of the modes 1-3 of said sealing layer; - according to variant 2 of the CMC material or of the precursor of said CMC, optionally combined with a sealing layer in particular according to one of the modes 1-3 of said sealing layer; - according to variant 3 of the CMC material or of the precursor of said CMC, optionally combined with a sealing layer, in particular according to one of the modes 1-3 of said sealing layer.

[0174] In the embodiment shown in [Fig. 2a], the spacer 202 is completely watertight throughout. To achieve this, the spacer 202 comprises a main layer 204 made according to the embodiment 3 described above. For example, the main layer 204 is made according to embodiment 3.3, that is, with a CMC material, or a precursor of a CMC material, the matrix of which is formed by, or comprises, a glass-ceramic. In this embodiment, the spacer 202 consists of the main layer 204 such that said main layer 204 forms said spacer 202.

[0175] In the variant shown in [Fig. 2b], the spacer 202 is not sealed throughout, but only on the surface. To achieve this, the spacer 202 comprises a main layer 204 made according to variant 1 described above. The main layer 204 of the spacer 202 is made of a CMC material, or a precursor of said CMC material, which is not gas-tight, and the spacer 202 further comprises a layer 206 of sealing material deposited on the main layer. 204. The sealing layer 206 can be obtained according to one of the sealing layer modes 1-3 described above, and in particular according to mode 2 in which the sealing layer 206 is formed by a sintered glass, preferably a precursor glass of glass-ceramic.

[0176] In the variant shown in [Fig. 2c], the spacer 202 comprises a main layer 204 which is gas-tight throughout, but only in certain parts of the spacer, according to a sealing pattern 208. To achieve this, the main layer 204 of the spacer 202 is made according to variant 2 described above. The main layer 204 of the spacer 202 is made of a CMC material, or a precursor of said CMC material, which is gas-tight only in certain determined parts according to the sealing pattern 208.

[0177] In the examples in FIGURES 2a-2c, all the sealing joints 114 are retained. Thus, the electrochemical device 200 comprises: - sealing gaskets 110 between the spacer 202 and each of the interconnectors 102 and 104, on either side of the CE supply channel for the incoming gas flow, - sealing gaskets 110 between the spacer 202 and each of the interconnectors 102 and 104, on either side of the CS exhaust channel for the outgoing gas flow, - sealing joints 110 between cell 106 and each of the interconnectors 102 and 104, at the periphery of cell 106.

[0178] FIGURES 3a-3c are schematic representations of three variants of a second non-limiting embodiment of an electrochemical device according to the invention, following a cross-sectional view.

[0179] Each of the variants of electrochemical device 300 in FIGURES 3a-3c includes all the elements of electrochemical device 200, except with respect to the differences indicated below.

[0180] The electrochemical device 300 does not include sealing gaskets 110 between the spacer 202 and each of the interconnectors 102 and 104. Indeed, depending on the applications, the spacer 202 being already sealed, either on the surface or in depth, it is quite possible not to use sealing gaskets between the spacer 202 and the interconnectors 102-104.

[0181] Like device 200, the spacer 202 of device 300 can be made gas-tight according to one of the variants described above.

[0182] In the variant shown in [Fig. 3a], the spacer 202 comprises a main layer 204 which is fully watertight throughout. To achieve this, the main layer 204 of the spacer 202 is made according to variant 3 described above. For example, the main layer 204 of the spacer 202 is made according to variant 3.2, that is to say, with a CMC material, or a precursor of a CMC material, the matrix of which is formed by, or comprises, a sintered glass, said glass preferably being a precursor glass of glass-ceramic. In this embodiment, the spacer 202 consists of the main layer 204 such that said main layer 204 forms said spacer 202.

[0183] In the variant shown in [Fig. 3b], the spacer 202 is not sealed throughout, but only on the surface. To achieve this, the main layer 204 of the spacer 202 is made according to variant 1 described above. The main layer 204 of the spacer 202 is made of a CMC material, or a precursor of said CMC material, which is not gas-tight, and the spacer 202 further comprises a layer 206 of sealing material deposited on the main layer 204. The sealing layer 206 can be obtained according to one of the sealing layer modes 1-3 described above, and in particular according to mode 2 in which the sealing layer 204 is formed by sintered glass, preferably a glass-ceramic precursor glass.

[0184] In the variant shown in [Fig. 3c], the main layer 204 of the spacer 202 is fully sealed, but only in certain parts of the spacer, according to a sealing pattern 208. To achieve this, the main layer 204 of the spacer 202 is made according to variant 2 described above. The main layer 204 of the spacer 202 is made of a CMC material, or a precursor of said CMC material, which is gas-tight only in certain determined parts according to the sealing pattern 208.

[0185] It should be noted that, in the electrochemical device 300, the sealing joints 110 arranged between the cell 106 and each of the interconnectors 102 and 104, at the periphery of the cell 106, are retained.

[0186] According to an alternative not shown, the electrochemical device 300 may include only some of the seals 110 located between the spacer 202 and at least one of the interconnectors 102 and 104, and shown in the electrochemical device 200. Indeed, depending on the application, since the spacer 202 is already sealed, it is quite possible not to use as many seals as those shown in FIGURE 2, and thus reduce the complexity of the architecture of the electrochemical device while retaining some of the seals 110.

[0187] FIGURES 4a-4c are schematic representations of three variants of another non-limiting embodiment of an electrochemical device according to the invention, in cross-section.

[0188] Each of the variants of the electrochemical device 400 in FIGURES 4a-4c includes all the elements of the electrochemical device 200, except for the differences indicated below.

[0189] In the electrochemical device 400, the electrochemical cell 106 is arranged on the spacer 202, above the central opening provided in said spacer 202. To this end, the spacer 202 has, around the central opening, a portion 402, or a lip 402, of lesser thickness compared to the rest of the spacer 202. This lip 402 forms a support for the electrochemical cell 106. Thus, in the electrochemical device 400, the spacer 202 forms a support for the electrochemical cell 106.

[0190] Of course, the thickness of the cell 106 and / or the thickness of the spacer 202, in particular the thickness of the lip 402, can be adjusted to ensure electrical contacts between the electrochemical cell 106 and the interconnectors.

[0191] Like devices 200 and 300, the spacer 202 of device 400 can be made gas-tight according to one of the variants described above.

[0192] In the variant shown in [Fig. 4a], the spacer 202 comprises a main layer 204 that is fully sealed throughout. To achieve this, the main layer 204 of the spacer 202 is made according to variant 3 described above. For example, the main layer 204 of the spacer 202 is made according to mode 3.3, i.e., with a CMC material, or a precursor of a CMC material, the matrix of which is formed by, or comprises, a glass-ceramic.

[0193] In the variant shown in [Fig. 4b], the spacer 202 is not sealed throughout, but only on the surface. To achieve this, the main layer 204 of the spacer is made according to variant 1 described above. The main layer 204 of the spacer 202 is made of a CMC material, or a precursor of said CMC material, which is not gas-tight, and the spacer 202 further comprises a layer 206 of sealing material deposited on said main layer 204. The sealing layer 204 can be obtained according to one of the modes 1-3 described above, and in particular according to mode 2 in which the sealing layer 206 is formed by sintered glass, preferably a precursor glass of glass-ceramic.

[0194] In the variant shown in [Fig.4c], the main layer 204 of the spacer 202 is sealed in depth, but only in certain parts of the spacer 202, according to a sealing pattern 208. To achieve this, the main layer 204 of the spacer 202 is made according to variant 2 described above: the main layer 204 of the spacer 202 is made with a CMC material, or a precursor of said CMC material, which is gas-tight only in certain parts determined according to the sealing pattern 208.

[0195] In the example shown in FIGURES 4a-4c, the electrochemical device 400 comprises: - sealing gaskets 110 between the spacer 202 and each of the interconnectors 102 and 104, on either side of the CE supply channel for the incoming gas flow, - sealing gaskets 110 between the spacer 202 and each of the interconnectors 102 and 104, on either side of the CS exhaust channel for the outgoing gas flow, - at least one sealing joint 110 between cell 106 and spacer 202, at the periphery of cell 106.

[0196] According to an alternative not shown, the positioning of the electrochemical cell 106 as described with reference to FIGURES 4a-4c can be used in the electrochemical device 300 of FIGURES 3a-3c.

[0197] It should be noted that the FIGURES represent the electrochemical device in schematic form and not all elements of said electrochemical device are shown for the sake of clarity and to avoid cluttering the FIGURES. For example, the electrochemical device may include an electrical contact layer (not shown) between the electrochemical cell 106 and the interconnector 102 and / or an electrical contact layer between the electrochemical cell 106 and the interconnector 104.

[0198] Fig. 5 is a schematic representation of a non-limiting example embodiment of an electrochemical system according to the invention.

[0199] System 500 can for example be an electrolyzer, and in particular a solid oxide electrolyzer, SOE.

[0200] The SOE solid oxide electrolyzer can be used for high-temperature electrolysis temperature, for example between 600°C and 800°C, of ​​water vapor to generate a flow of hydrogen.

[0201] The electrolyzer 500 comprises a stack 502, also called a stack, of Unitary electrochemical devices 504r504n. Each unitary electrochemical device 504; can be any one of the electrochemical devices 200, 300 or 400 described above.

[0202] The unit electrochemical devices 504i and 504n which are located at the ends of the stack 502 do not include an interconnector on the end side of the stack 502 but connectors 506 and 508, also called manifold, for supplying gas flow and electricity to the stack 502.

[0203] Stack 502 is supplied with an electric current 510 for carrying out the electrochemical reaction.

[0204] The stack 502 is supplied with a first inlet gas stream 512 at high temperature and rich in water vapor. The electrochemical reaction produces a first outlet gas stream 514 rich in hydrogen and a second outlet gas stream 516 rich in oxygen, by decomposition of water vapor molecules in contact with the electrochemical cell 106 of each electrochemical device 504. Optionally, the stack 502 can be supplied with a second high-temperature gas stream 518, for example air, for example to equalize the pressures within the stack 502.

[0205] Of course, the electrochemical system 500 may include other components, such as heat exchangers, a hydrogen purification unit, safety valves, etc., which are not shown in [Fig. 5].

[0206] Following another example not shown, the electrochemical system according to the invention can be a fuel cell, and in particular a solid oxide fuel cell, SOFC, for producing an electric current by oxidation of hydrogen molecules for example.

[0207] Of course, the invention is not limited to the examples just described.

Claims

Demands

1. Spacer (202) for solid oxide electrochemical device (200;300;400), said device (200;300;400) comprising: - at least one interconnector (102,104), - a solid oxide electrochemical cell (106) disposed between said interconnector (102,104) and another interconnector (102; 104), and - said spacer (202), disposed between said interconnectors (102,104), in particular, around said cell (106); said spacer (202): - comprising a layer (204), said main layer, made of a ceramic matrix composite material, said CMC material, or of a precursor of said CMC material, electrically insulating; and - being partly, or totally, gas-tight. characterized in that said spacer (202) comprises, on part or all of the main layer (204), a gas sealing layer (206) made of a sealing material.

2. Spacer (202) according to the preceding claim, characterized in that the sealing material is, or comprises: - glass particles, in particular glass precursor particles of glass ceramic; or - a layer of sintered glass, and in particular a layer of glass precursor of glass ceramic; or - a layer of glass ceramic.

3. Spacer (202) according to any one of the preceding claims, characterized in that the CMC material comprises a matrix that is not gas-tight, said sealing layer (206) being deposited over the entirety of the main layer.

4. Spacer (202) according to any one of claims 1 or 2, characterized in that the CMC material comprises a matrix waterproof in depth, on only part of the main layer (204).

5. Spacer (202) according to any one of claims 1 or 2, characterized in that the CMC material comprises a deep-sealing matrix over the entire main layer (204).

6. Spacer (202) according to any one of claims 4 or 5, characterized in that, for at least a sealed part of the main layer (204): - the CMC precursor matrix comprises glass particles, in particular glass precursor particles of glass ceramic; or - the CMC matrix, or the CMC precursor matrix, is, or comprises, sintered glass, in particular glass precursor of glass ceramic; or - the CMC matrix, or the CMC precursor matrix, is, or comprises, a glass ceramic.

7. Spacer (202) according to any one of the preceding claims, characterized in that said spacer (202) is in the form of a single, one-piece unit.

8. Spacer (202) according to any one of the preceding claims, characterized in that said spacer (202) has a central opening allowing: - the passage of gas to, or from, the electrochemical cell (106); and / or - an electrical contact between: • the electrochemical cell (106), and • one, or each, interconnector (102,104), or an electrical contact piece disposed between said electrochemical cell (106) and said interconnector (102,104).

9. Solid oxide electrochemical device (200;300;400) comprising: - at least one electrically conductive interconnector (102,104), - a solid oxide electrochemical cell (106) disposed between said interconnector (102,104) and another interconnector (102,104), and - a spacer (202), according to any one of the preceding claims, disposed between said two interconnectors (102,104).

10. Device (200;300;400) according to the preceding claim, characterized in that the spacer (202) has a thickness greater than the thickness of the electrochemical cell (106).

11. Device (400) according to any one of claims 9 or 10, characterized in that the electrochemical cell (106) is disposed on the spacer (202), above a central opening provided in said spacer (202).

12. Device (200;300) according to any one of claims 9 or 10, characterized in that the electrochemical cell (106) is disposed inside a central opening provided in the spacer (202), in particular without physical contact with said spacer (202).

13. Solid oxide electrochemical system (500) comprising a stack (502) of several electrochemical devices (502r502n) of which at least one is an electrochemical device (200;300;400) according to any one of claims 9 to 12.

14. System (500) according to the preceding claim, characterized in that said system is a solid oxide electrolyzer for the electrolysis of water vapor at high temperature.

15. System according to claim 13, characterized in that said system is a solid oxide fuel cell.

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