Method for manufacturing a solid oxide electrochemical reactor comprising triple-layer sealing and insulation assemblies

Abstract

A method for manufacturing a solid oxide electrochemical reactor, comprising the following steps: – making an electrically insulating support (1) with through-holes (2); – depositing a first layer of fusible seal (20) on an interconnecting plate (6) and placing the electrically insulating support (1) thereon; – depositing an interstitial bead of fusible seal (21) in the through-holes (2); – placing a second layer of fusible seal (22) on the electrically insulating support (1); – creating and pressing an alternating stack and heating it to a fusible seal melting temperature, so as to fuse the first layer of fusible seal (20), the interstitial bead of fusible seal (21), and the second layer of fusible seal (22), the fusible seal forming a seal extending into the through-holes (2) of the electrically insulating support (1) and connecting two interconnecting plates (6) through the through-holes (2). Figure for the abstract: Fig.10.

Description

Title of the invention: Method for manufacturing a solid oxide electrochemical reactor comprising triple-layer sealing and insulation assemblies Technical field

[0001] The invention relates to the technical field of solid oxide electrochemical reactors, and more precisely solid oxide electrolyzers (SOEC, "Solid Oxide Electrolyzer Cell") and solid oxide fuel cells (SOFC, "Solid Oxide Fuel Cell").

[0002] These electrolysers and fuel cells are electrochemical reactors of the same nature but with reverse operation, operating at high temperature, currently of the order of 600°C to 1000°C. They make it possible, in the case of an electrolyser, to obtain dihydrogen and dioxygen from water (for the electrolysis of water), and in the case of a fuel cell, to provide electrical energy from dihydrogen, or another fuel, and dioxygen.

[0003] These electrochemical reactors consist of one or more stacks of electrochemical cells held tightly together to ensure electrical contacts and sealing. Each electrochemical cell comprises a layer of solid electrolyte sandwiched between two layers of electrodes. The layer of solid electrolyte allows the transport of ions between the anodic and cathodic layers, the latter being the site of the chemical reactions.

[0004] In a "SOEC" type reactor, the water molecule is dissociated into dihydrogen at the hydrogen electrode (cathode), the O2 ions migrate through the electrolyte to recombine on the oxygen electrode side (anode) into dioxygen. "SOEC" cells thus produce dihydrogen by dissociating water molecules.

[0005] In a "SOFC" type reactor, oxygen is reduced at the oxygen electrode (cathode), the O2 ions migrate through the electrolyte. An oxidation reaction then takes place at the hydrogen electrode (anode) and the "SOFC" cells thus produce electricity and water by combining dihydrogen and dioxygen.

[0006] These electrochemical reactors are arranged in alternating stacks of electrochemical cells and interconnection plates. The interconnection plates are interposed between the cells to ensure sealing between cells, as well as to manage the supply and collection of gases or liquids participating in the reaction. Sealing between interconnection plates is therefore a critical point to avoid mixing of fluids.

[0007] The interconnection plates are also conductive and allow the connection electrical insulation of the cells. The electrical insulation between interconnection plates is therefore also a critical point, to avoid short-circuiting a cell.

[0008] The sealing and electrical insulation within these electrochemical reactors are therefore among the most critical points in operation, for reasons of performance and quality, operational safety, lifespan and security. PRIOR ART

[0009] Document FR3014246 describes an electrochemical reactor comprising means high-performance sealing.

[0010] This electrochemical reactor comprises: - an alternating stack of electrochemical cells and interconnection plates, in a stacking direction, the electrochemical cells each comprising a layer of solid electrolyte arranged between two layers of electrodes, and the interconnection plates comprising electrically conductive plates provided with reaction fluid distribution channels; - at least one transverse channel for circulation of reaction fluids between the interconnection plates; - sealing and insulation assemblies arranged between the interconnection plates.

[0011] These sealing means give good functional results. However, they are difficult and expensive to manufacture and implement, and suffer from significant manufacturing hazards, particularly for stacks comprising a large number of cells. In particular, this solution is not very suitable in the context of industrial production, which is nevertheless necessary for the deployment of solid oxide electrochemical reactor solutions. Statement of the invention

[0012] The aim of the invention is to improve the solid oxide electrochemical reactors of the prior art.

[0013] To this end, the invention relates to a method for manufacturing a solid oxide electrochemical reactor which comprises: - an alternating stack of electrochemical cells and interconnection plates, in a stacking direction, the electrochemical cells each comprising a layer of solid electrolyte arranged between two layers of electrodes, and the interconnection plates comprising electrically conductive plates provided with reaction fluid distribution channels; - at least one transverse channel for circulation of reaction fluids between the interconnection plates; - sealing and insulation assemblies arranged between the plates interconnection.

[0014] This method comprises the following steps: - production of an electrically insulating support comprising a sheet of insulating material pierced with through openings; - deposit a first bed of electrically insulating fusible joint on an interconnection plate; - place the electrically insulating support on the first bed of fusible joint; - deposit an interstitial bead of electrically insulating fusible joint in the through openings of the electrically insulating support; - place a second bed of fusible joint on the electrically insulating support; - producing said alternating stack of electrochemical cells and interconnection plates, with the electrically insulating support positioned at the locations of said sealing and insulation assemblies; - pressing said alternating stack and bringing it to a fusible joint melting temperature, so as to fuse the first fusible joint bed, the interstitial bead of fusible joint, and the second fusible joint bed, the fusible joint forming a seal extending into the through openings of the electrically insulating support and connecting two interconnection plates through the through openings.

[0015] The reaction fluids referred to are the fluids that are brought to the electrodes and the fluids that are drained from the electrodes. These are, depending on the operating mode (fuel cell or electrolyzer) of the electrochemical reactor, high-temperature water vapor, dihydrogen, dioxygen, etc.

[0016] The method according to the invention makes it possible to produce electrochemical reactors benefiting from the highest performance in terms of electrical insulation and sealing, jointly.

[0017] In the sealing and insulation assemblies thus produced, the electrically insulating support and the fusible joint cooperate to form a seal which adheres to the interconnection plates, so as to ensure electrical insulation and to form a gas-tight barrier at the interfaces between this sealing and insulation assembly and the interconnection plates.

[0018] In addition to the performance provided by the use of sealing and insulation assemblies, the invention allows better control of manufacturing, and therefore leads to better quality electrochemical reactors.

[0019] In the prior art, the implementation of sealing and insulation assemblies is essentially the responsibility of the laboratory or small series production, with meticulous and difficult to repeat handling. The invention allows industrial-scale production of solid oxide electrochemical reactors, with the required quality and repeatability. The invention thus contributes to the deployment of these solutions which are required for the future, in a context of diversification of energy sources.

[0020] The invention makes it possible to increase production scales, also by increasing the capacities of solid oxide electrochemical reactors, by concretely allowing the increase in the size of the stacks. The invention is thus particularly suitable for the current objectives of increasing the number of layers in the reactors, leading to an increase in the height of the stacks, and increased complexity in the control of their manufacture. The management of height variations is in fact particularly critical during the manufacture of the reactors.

[0021] The expected performance for future solid oxide electrochemical reactors tends to require the implementation of very high stacks which may include hundreds of interconnection plates. In addition, the cumulative length of the sealing barriers (i.e. the addition of the sealing joint lengths) for each stage of an electrochemical reactor may be of the order of 2 meters. In the case, for example, of a 20 kW power reactor consisting of 75 stages, a cumulative length of the sealing joints of approximately 150 m is achieved.

[0022] The invention allows a lowering of the total height of the stacks before pressing. The lowering of the stack height before pressing also results in a reduction of the lowering stroke of the stack during clamping, thus reducing the complexity of the necessary guides, and reducing the risk of collapse of the stack.

[0023] The invention thus improves the quality of the sealing and electrical insulation barriers, and simplifies the assembly of the stacks.

[0024] The method according to the invention may include the following additional characteristics, alone or in combination:

[0025] - prior to the step of placing a second bed on the electrically insulating support of fusible joint, the method comprises a step of depositing said second bed of fusible joint on a second interconnection plate, and, in the step of arranging on the electrically insulating support a second bed of fusible joint, the assembly formed of the second interconnection plate and the second bed of fusible joint is arranged on the electrically insulating support;

[0026] - the first bed of fusible joint is made by depositing extruded paste;

[0027] - the first bed of fusible joint is made by depositing fusible joint beads adjacent;

[0028] - the upper surface of the first fusible joint bed forms undulations;

[0029] - the second bed of fusible joint is made by depositing extruded paste;

[0030] - the second fusible joint bed is made by fusible joint cords adjacent;

[0031] - the upper surface of the second fusible joint bed forms undulations;

[0032] - the volume of the through openings is entirely filled by the cord in fusible joint interstitial;

[0033] - the interstitial bead of fusible joint is flush with the surface of the insulating support electric, on each of its faces;

[0034] - in the step of producing the electrically insulating support, the through openings are arranged in discontinuous grooves arranged along joint lines;

[0035] - in the step of producing the electrically insulating support, said sheet of material electrically insulating is further pierced with a central window for the positioning of an electrochemical cell, the joining lines being arranged around this central window;

[0036] - in the step of producing the electrically insulating support, said sheet of material electrically insulating is further pierced with at least one side window intended for the passage of the transverse channel for circulation of the reaction fluids, the joining lines being arranged around this side window;

[0037] - in the step of producing the electrically insulating support, several joining lines parallels are arranged side by side;

[0038] - said parallel joining lines are formed of discontinuous grooves which have discontinuities arranged in staggered rows;

[0039] - the electrically insulating support comprises a single-piece frame;

[0040] - in the step of producing an alternating stack of electrochemical cells and interconnection plates, the stacking is carried out in a press comprising guiding means following the stacking direction;

[0041] - the first fusible joint bed, the interstitial fusible joint bead, and the second fusible joint bed comprises: a glass, or glass-ceramic, or ceramic powder; a solvent; and a binder. PRESENTATION OF FIGURES

[0042] Other characteristics and advantages of the invention will emerge from the non-limiting description which follows, with reference to the appended drawings in which:

[0043] - [Fig. 1] is a perspective view of an electrically insulating support implemented in the method according to the invention;

[0044] - [Fig.2] is a partial sectional view of an alternating stack of electric cells trochemicals and interconnection plates, implemented in the method according to the invention;

[0045] - [Fig.3] is a detailed view of a sealing and insulation assembly put in works in the method according to the invention;

[0046] - [Fig.4], [Fig.5], [Fig.6], [Fig.7], [Fig.8], [Fig.9], [Fig.10], [Fig. 11] and [Fig. 12] illustrate steps of the method according to the invention.

[0047] Elements similar and common to the various embodiments bear the same reference numbers in the figures. DETAILED DESCRIPTION

[0048] The subject of the invention is a method for manufacturing a solid oxide electrochemical reactor, such as a solid oxide fuel cell, or a solid oxide electrolyser, with an operating temperature of the order of 600 to 1000°C. This electrochemical reactor can also be reversible, being able to operate alternately in the two modes (solid oxide electrolyser or solid oxide fuel cell).

[0049] The solid oxide electrochemical reactor comprises: - an alternating stack of electrochemical cells and interconnection plates, in a stacking direction, the electrochemical cells each comprising a layer of solid electrolyte arranged between two layers of electrodes, and the interconnection plates comprising electrically conductive plates provided with reaction fluid distribution channels; - at least one transverse channel for circulation of reaction fluids between the interconnection plates; - sealing and insulation assemblies arranged between the interconnection plates.

[0050] Solid oxide electrochemical reactors are of known construction and will not be described in more detail here, apart from the elements relating to the invention which concerns the method of manufacturing such an electrochemical reactor.

[0051] The electrochemical reactor illustrated has, for example, a constitution similar to that described in document FR3014246, and notably comprises sealing and insulation assemblies, arranged between the interconnection plates.

[0052] [Fig.l] illustrates an electrically insulating support 1 provided to form one of the sealing and insulating assemblies of the electrochemical reactor according to the invention.

[0053] This electrically insulating support 1 comprises a sheet of insulating material pierced with a through opening 2. This sheet of insulating material is preferably made of a material with high insulating properties, for example a mica sheet. Any mineral compound other than mica can also be used, as well as ceramics, polymers, or any other material suitable for the operating temperature and having the required electrically insulating properties.

[0054] In the present example, the electrically insulating support 1 comprises a single-piece frame which has the general shape of a square frame, intended to take place in a stack of electrochemical cells and interconnection plates which are themselves square. electrically insulating support 1 of this particular example forms a frame with a central window 3 provided for the positioning of an electrochemical cell. This assembly will be sandwiched between two interconnection plates to form the elementary pattern of the stack.

[0055] The electrically insulating support 1 may also, as a variant, have any other shape to correspond to stacks of different shapes (rectangular, circular, oval, etc.) and may also have shapes other than a frame, such as a linear shape, and may perform its function on only a portion of an area between two interconnection plates.

[0056] The electrically insulating support 1 further comprises, in this example, lateral windows 4 which participate in the constitution of transverse channels for the circulation of reaction fluids between the interconnection plates.

[0057] The through openings 2 of the insulating support 1 are, in this example, produced in the form of discontinuous grooves extending along the joining lines. These joining lines are arranged around the central window 3 and around the side windows 4, according to the example illustrated in [Fig.l].

[0058] Several joining lines can be arranged in parallel and side by side, this is the case of the joining lines between each side window 4 and the edge of the electrically insulating support 1. In this case, the discontinuities of the grooves are preferably placed in staggered rows, in order to lengthen the possible leak path between two adjacent joining lines, to improve the sealing of the finished stack. The material of the electrically insulating support 1 can therefore have a certain porosity, which will not harm the sealing once joints are put in place in the discontinuous grooves constituting the through openings 2.

[0059] [Fig. 2] is a partial sectional view illustrating an elementary pattern of the stack of the electrochemical reactor, with an electrochemical cell 5 arranged between two interconnection plates 6. An alternating stack within the meaning of the present invention thus comprises, in a known manner, an alternation of electrochemical cells 5 and interconnection plates 6, as many times as necessary depending on the size of the desired stack, superimposed in a stacking direction D.

[0060] Each electrochemical cell 5 comprises a solid electrolyte layer 8 disposed between two electrode layers 9, 10, one of which is an anode and the other is a cathode. Each interconnection plate 6 comprises different layers 6A, 6B, 6C allowing the distribution of the reaction fluids. The electrochemical cells 5 and the interconnection plates 6 may, for example, conform to the description of document WO2016026740.

[0061] The partial section of [Fig.2] illustrates a portion of the edge of this elementary pattern of the alternating stack of the electrochemical reactor, and illustrates in particular a transverse channel 7 for circulation of the reaction fluids between the interconnection plates 6. In a known manner, each transverse channel 7 allows a reaction fluid (whether supplied or produced at the level of the electrode layers 9, 10) to circulate from one interconnection plate 6 to the other.

[0062] The interconnection plates 6 of this example comprise three layers 6A, 6B, 6C. In the view of [Fig.2], where only one electrochemical cell 5 is illustrated: - a first external layer 6A is provided with reaction fluid distribution channels for the electrochemical cell which is located above the interconnection plate 6 in question; - a second external layer 6B is provided with reaction fluid distribution channels for the electrochemical cell which is located below the interconnection plate 6 in question; - a central layer 6C is provided with channels intended for the circulation of a cooling fluid.

[0063] The reaction fluid distribution channels allow either the supply of fluids necessary for the reaction to the electrodes, or the drainage from the electrodes of the fluids produced by the reaction (water vapor, oxygen, hydrogen, etc.).

[0064] In the example illustrated in [Fig.2], layer 6A of the lower interconnection plate 6 manages the reaction fluids for the lower electrode 10, while layer 6B of the upper interconnection plate 6 manages the reaction fluids for the upper electrode 9.

[0065] Sealing means allow the reaction fluids to be directed to or from the appropriate electrodes 9, 10, avoiding mixing of the fluids. In this example, a seal 11 is arranged between the solid electrolyte layer 8 and the interconnection plate 6 below, to divide the flows specific to each electrode.

[0066] The electrochemical reactor further comprises a sealing and insulation assembly 12 making it possible to create a seal between the interconnection plates 6.

[0067] This sealing and insulation assembly 12 is formed from the electrically insulating support 1 of [Fig.l], associated with a seal 13 which extends into the through openings 2 of the electrically insulating support 1 by connecting two interconnecting plates 6 through the through openings 2.

[0068] [Fig. 3] is a detailed perspective view of the sealing and insulation assembly 12 with the electrically insulating support 1, one of its through openings 2, and the sealing gasket 13 which has two faces 14 each intended to adhere to an interconnection plate 6. This figure thus presents the sealing barrier formed by the method according to the invention.

[0069] High-performance sealing is thus achieved from one interconnection plate 6 to the other, by a sealing gasket 13 passing through each through opening 2.

[0070] The arrangement of the through openings 2, here produced in the form of joining lines along which discontinuous grooves extend, ensures that the physical integrity of the electrically insulating support 1 is maintained, which remains in one piece, thus ensuring proper positioning of all the joints. The joining lines may be straight lines, curved lines, dotted lines, wavy lines, or any other shape suitable for a particular application.

[0071] The method according to the invention comprises a first step of producing the electrically insulating support 1 of [Fig.l], pierced with the through openings 2. This step consists of cutting to size a sheet of electrically insulating material, mica in this example, and forming in this sheet the various windows 3, 4 required, as well as the through openings 2. Any suitable manufacturing method can be used here, for example: machining the mica sheet, laser cutting, punching, machining by milling, etc., or even molding or additive manufacturing for materials suitable for this.

[0072] The next step of the method consists of depositing at least a first bed of fusible joint 20 on an interconnection plate 6.

[0073] [Fig.4] illustrates in perspective the result of this deposition of fusible joint bed 20 and [Fig.5] is the corresponding front view. In these figures and the following ones, only portions of the interconnection plates 6 and the electrical insulating support 1 have been shown. The other portions of the stack, comprising the electrochemical cells 5, known elsewhere, have not been illustrated to simplify the figures.

[0074] The fusible joint bed 20 can be produced by depositing extruded paste. The entire fusible joint bed 20 can thus be produced by extrusion and then applied to the interconnection plate. According to another variant, the fusible joint bed 20 can for example be deposited in the form of paste by a particular extrusion device, such as a robotic arm equipped with a syringe. According to an advantageous embodiment, the fusible joint bed 20 is formed by this extrusion device depositing adjacent seal beads. These beads can be rectilinear, placed side by side and touching, for example beads with a width of the order of 1 to 2 mm. In the figures, the upper surface of the fusible joint bed 20, forming undulations, illustrates this formation into adjacent seal beads.The fusible joint bed 20 may also be deposited in a single pass, for example by an extrusion means adapted to directly provide the fusible joint in sheets or plates. Any other method suitable for depositing a fusible joint bed may be employed, for example by spraying, additive manufacturing, etc.

[0075] The material constituting the deposited fusible joint bed 20 is a material having a melting point beyond which it will form a seal impervious to reaction fluids and electrically insulating. Preferably, this material is based on glass or glass-ceramic. It can also be based on other materials, such as a ceramic or a suitable polymer.

[0076] In the present example, the fusible joint bed consists of a mixture of glass powder, an ethanol-type solvent, and a terpineol-type binder. This joint bed is fusible because when the melting point of the glass powder is reached, the glass powder agglutinates into molten glass, to form a joint capable of adhering to the interconnection plate 6. The glass powder in this example is ground glass, with an average particle size between 30 μm and 0.1 μm.

[0077] The next step of the method is illustrated in the perspective view of [Fig.6] and in the corresponding front view of [Fig.7]. This step consists of placing the electrically insulating support 1 on the joint bed 20.

[0078] Given the receiving surface offered by the joint bed 20, an intermediate drying operation of the joint bed can optionally be carried out, but is not necessary. The formation of adjacent joint beads in this example also guarantees a more stable reception, less sensitive to surface irregularities.

[0079] The perspective view of [Fig.8] and its corresponding front view illustrates the next step of the method, in which an interstitial bead of electrically insulating fusible joint 21 is deposited in the through openings 2 of the electrically insulating support 1.

[0080] The interstitial bead of fusible joint 21 is preferably of the same material as the bed of fusible joint 20, and deposited in the form of a paste by an extrusion device adapted to fill the volume of the through openings. At least one interstitial bead of fusible joint 21 is deposited in the through openings 2, it being understood that as many of these interstitial beads as necessary can be deposited, so as to preferably fill any volume of the through openings 2. The interstitial bead of fusible joint 21 can be deposited in one or more passes.

[0081] The interstitial bead of fusible joint 21 may be deposited by an extrusion device, for example the same extrusion device as the seal bed 20, such as a syringe manipulated by a robotic arm. The interstitial bead of fusible joint 21 may also be deposited by any other method, such as gravity deposition of fluid paste and possibly scraping, or by deposition of seal volumes preformed in the shape of the through openings 2.

[0082] In this example, the interstitial bead of fusible joint 21 is flush with the surface of the electrically insulating support 1, on each of its faces (see [Fig.9]).

[0083] A next step of the method consists of arranging a second bed of fusible joint 22 on the electrically insulating support 1. This step is illustrated in [Fig. 10] (view in perspective) and [Fig.l 1] (front view).

[0084] In the present example, the second fusible joint bed 22 is deposited jointly with an upper interconnection plate 6. This makes it possible to carry out in a single operation the positioning of the second fusible joint bed 22 and the alternating stacking of an electrochemical cell 5 with the two interconnection plates 6 which enclose it. To do this, the second fusible joint bed 22 will have been previously deposited on this upper interconnection plate 6, in the same way as the first fusible joint bed 20 was deposited on its interconnection plate 6 (as illustrated in FIGS. 4 and 5). The assembly formed by this upper interconnection plate and its second fusible joint bed 22 is then arranged (by its face comprising the second fusible joint bed 22) on the electrically insulating support 1, the through openings 2 of which are lined with the interstitial fusible joint beads 21.

[0085] This operation leads to the assembly of figures 10 and 11. The total volume of the first fusible joint bed 20, the interstitial fusible joint beads 21, and the second fusible joint bed 22 are determined with the aim of filling all the through openings 2, and of forming a joint layer between the electrically insulating support 1 and each interconnection plate 6. This volume can be calculated as accurately as possible, which implies that only a small excess thickness will have to be flattened during the fusion of the joint, drastically reducing the height travel of the stack during the following step.

[0086] The fact of preparing the fusible joint in three layers also makes it possible to do without any operation of shaping or rectification of the fusible joint elements, which could have been necessary in the prior art, such as cutting or flattening the pins left by the paste deposition operation, etc.

[0087] The next step of the method consists of producing the alternating stack of electrochemical cells 5 and interconnection plates 6, with the aim of producing the electrochemical reactor, with the electrically insulating support 1 arranged at the locations provided for the sealing and insulation assemblies 12. As previously, for reasons of clarity, only one elementary pattern of the stack has been illustrated (between two interconnection plates 6), it being understood that the stack comprises as many of these patterns as necessary. The invention allows stacks of significant height, for example of the order of 80 stages of electrochemical cells 5.

[0088] To produce this alternating stack, for example from the assembly of figures 10 and 11, a new first bed of seal 20 can be deposited on the upper face of the interconnection plate 6 from above, then a new electrically insulating support 1, then interstitial cords of fusible seal 21 are deposited in the through openings 2 of this electrically insulating support 1, then a new assembly of an interconnection plate 6 and a second bed of fusible seal 22 is deposited on the previous assembly, and so on.

[0089] The alternating stacking can also be achieved by first preparing sets of interconnection plates 6 coated on both their faces with a bed of fusible joint (a first bed of fusible joint 20 on one of its faces and a second bed of fusible joint 22 on the other of its faces).

[0090] Generally, an electrically insulating support 1 with its fusible joint cords 15 is provided for each stage of the stack, that is to say that such an assembly formed of the first fusible joint bed 20, of the electrically insulating support 1 with its through openings 2 lined with interstitial fusible joint cords 21, and of the second fusible joint bed 22, is arranged between each pair of interconnection plates 6.

[0091] From this stack assembly, sealing within the electrochemical reactor being manufactured can be achieved.

[0092] The alternating stacking assembly of figures 10 and 11 is preferably carried out in a press which advantageously comprises guide means 18 following the stacking direction D, for each element of the stack (the guide means 18 are shown diagrammatically by axis lines in [Fig. 11]).

[0093] The next operation of the method consists of pressing said alternating stack along the stacking direction D and bringing it to a melting temperature of the material of the different fusible joints. For each stage, the melting temperature is higher than the melting point of the first fusible joint bed 20, the interstitial beads 21 of fusible joint, and the second fusible joint bed 22, so as to obtain the fusion of the latter.

[0094] During this step, for each stage of the stack, the first bed of fusible joint 20, the interstitial beads of fusible joint 21, and the second bed of fusible joint 22 melt and mix under the effect of the applied pressure.

[0095] The different portions of fusible joint homogenize and thus form a seal 13 by agglomerating through the through openings 2 under the effect of the press, and by adhering to the interconnection plates 6 located opposite these through openings. A seal 13 is thus formed, by extending into the through openings 2 of the electrically insulating support 1, and by connecting two interconnection plates 6 through the through openings 2, as illustrated in [Fig. 12].

[0096] These essential operations in the manufacture of the electrochemical reactor are thus carried out, with the sealing and insulation assemblies 12 required to allow the operation of the electrochemical cells 5. The remainder of the manufacturing process of the electrochemical reactor (electrical and fluidic connections, etc.) takes place in a conventional manner.

[0097] Alternative embodiments may be envisaged. In particular, the shape of the electrically insulating support, and therefore of the sealing and insulation assembly 12 obtained, may vary and, for example, consist only of linear barriers. sealing, arranged at suitable locations around each electrochemical cell 5, rather than in a frame-like manner as in the illustrated example. Similarly, the sealing and insulation assemblies 12 may be provided for any type of sealing required between two interconnection plates 6, other than sealing around the transverse channels 7 and sealing towards the outside of the reactor.

[0098] Furthermore, the material of the three fusible joint layers (first fusible joint bed 20, fusible joint beads 21, and second fusible joint bed 22) may vary, although the three layers are intended to agglutinate during their fusion. The particle size of the glass powder, or the viscosity of the product, may, for example, be different from one layer to another.

Claims

Claims

1. A method of manufacturing a solid oxide electrochemical reactor which comprises: - an alternating stack of electrochemical cells (5) and interconnection plates (6), in a stacking direction (D), the electrochemical cells (5) each comprising a layer of solid electrolyte (8) arranged between two layers of electrodes (9, 10), and the interconnection plates (6) comprising electrically conductive plates provided with reaction fluid distribution channels; - at least one transverse channel (7) for circulation of reaction fluids between the interconnection plates (6); - sealing and insulation assemblies (12) arranged between the interconnection plates (6); this method being characterized in that it comprises the following steps: - production of an electrically insulating support (1) comprising a sheet of insulating material pierced with through openings (2); - depositing a first bed of electrically insulating fusible joint (20) on an interconnection plate (6); - placing the electrically insulating support (1) on the first bed of fusible joint (20); - depositing an interstitial bead of electrically insulating fusible joint (21) in the through openings (2) of the electrically insulating support (D; - placing on the electrically insulating support (1) a second bed of fusible joint (22); - producing said alternating stack of electrochemical cells (5) and interconnection plates (6), with the electrically insulating support (1) positioned at the locations of said sealing and insulation assemblies (12); - pressing said alternating stack and bringing it to a melting temperature of the fusible joint, so as to fuse the first fusible joint bed (20), the interstitial bead of fusible joint (21), and the second fusible joint bed (22), the fusible joint forming a seal (13) extending into the through openings (2) of the electrically insulating support (1) and connecting two interconnection plates (6) through the through openings (2).

2. Method according to claim 1, characterized in that, prior to the step of arranging on the electrically insulating support (1) a second bed of fusible joint (22), the method comprises a step of depositing said second bed of fusible joint (22) on a second interconnection plate (6), and in that, in the step of arranging on the electrically insulating support (1) a second bed of fusible joint (22), the assembly formed by the second interconnection plate (6) and the second bed of fusible joint (22) is arranged on the electrically insulating support (1).

3. Method according to one of claims 1 or 2, characterized in that the first bed of fusible joint (20) is produced by depositing extruded paste.

4. Method according to claim 3, characterized in that the first fusible joint bed (20) is produced by depositing adjacent fusible joint beads.

5. Method according to one of claims 3 or 4, characterized in that the upper surface of the first fusible joint bed (20) forms undulations.

6. Method according to one of the preceding claims, characterized in that the second bed of fusible joint (22) is produced by depositing extruded paste.

7. Method according to claim 6, characterized in that the second fusible joint bed (22) is made by adjacent fusible joint beads.

8. Method according to one of claims 6 or 7, characterized in that the upper surface of the second fusible joint bed (22) forms undulations.

9. Method according to one of the preceding claims, characterized in that the volume of the through openings (2) is entirely filled by the interstitial bead of fusible joint (21).

10. Method according to one of the preceding claims, characterized in that the interstitial bead of fusible joint (21) is flush with the surface of the electrically insulating support (1), on each of its faces.

11. Method according to one of the preceding claims, characterized in that, in the step of producing the electrically insulating support (1), the through openings (2) are arranged in discontinuous grooves arranged along joining lines.

12. Method according to claim 11, characterized in that, in the step of producing the electrically insulating support (1), said sheet of electrically insulating material is further pierced with a central window (3) for

13.

14.

15.

16.

17.

18. the positioning of an electrochemical cell (5), the joining lines being arranged around this central window (3). Method according to one of claims 11 or 12, characterized in that, in the step of producing the electrically insulating support (1), said sheet of electrically insulating material is further pierced with at least one lateral window (4) intended for the passage of the transverse channel (7) for circulation of the reaction fluids, the joining lines being arranged around this lateral window (4). Method according to one of claims 11 to 13, characterized in that, in the step of producing the electrically insulating support (1), several parallel joining lines are arranged side by side. Method according to claim 14, characterized in that said parallel joining lines are formed of discontinuous grooves which comprise discontinuities arranged in staggered rows. Method according to one of the preceding claims, characterized in that the electrically insulating support (1) comprises a single-piece frame. Method according to one of the preceding claims, characterized in that, in the step of producing an alternating stack of electrochemical cells (5) and interconnection plates (6), the stack is produced in a press comprising guide means (18) following the stacking direction (D). Method according to one of the preceding claims, characterized in that the first fusible joint bed (20), the interstitial fusible joint bead (21), and the second fusible joint bed (22) comprise: a glass, or glass-ceramic, or ceramic powder; a solvent; and a binder.

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