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 specifically to solid oxide electrolyzers (SOEC, "Solid Oxide Electrolyzer Cell") and solid oxide fuel cells (SOFC, "Solid Oxide Fuel Cell").

[0002] These electrolyzers and fuel cells are electrochemical reactors of the same nature but with reversed operation, operating at high temperature, currently on the order of 600°C to 1000°C. In the case of an electrolyzer, they allow the production of dihydrogen and dioxygen from water (for the electrolysis of water), and in the case of a fuel cell, the provision of 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 contact and sealing. Each electrochemical cell comprises a layer of solid electrolyte sandwiched between two layers of electrodes. The solid electrolyte layer 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), and the O2 ions migrate through the electrolyte to recombine at the oxygen electrode (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), and 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 interconnecting plates. The interconnecting plates are placed between the cells to ensure a seal between them, as well as to manage the supply and collection of the gases or liquids participating in the reaction. The seal between the interconnecting plates is therefore critical to preventing the mixing of fluids.

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

[0008] Sealing and electrical insulation within these electrochemical reactors are therefore among the most critical points during operation, for reasons of performance and quality, operational reliability, service life, and safety. PRIOR ART

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

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

[0011] These sealing methods provide good functional results. However, they are difficult and expensive to manufacture and implement, and suffer from significant manufacturing uncertainties, particularly for stacks with a large number of cells. In particular, this solution is not well-suited to industrial production, which is nevertheless necessary for the deployment of solid oxide electrochemical reactor solutions. Description of the invention

[0012] The invention aims to improve prior art solid oxide electrochemical reactors.

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

[0014] This process comprises the following steps: - creation of an electrical insulating support comprising a sheet of insulating material pierced with through openings; - place a first layer of electrically insulating fusible joint on an interconnection plate; - place the electrical insulating support on the first bed of fusible joint; - deposit an interstitial bead of electrically insulating fusible sealant in the through openings of the electrically insulating support; - place a second layer of fusible seal on the electrical insulating support; - to carry out the said alternating stacking of electrochemical cells and interconnecting plates, with the electrical insulating support positioned at the locations of said sealing and insulation assemblies; - press said alternating stack and bring it to a melting temperature of the fusible joint, so as to fuse the first bed of fusible joint, the interstitial cord of fusible joint, and the second bed of fusible joint, the fusible joint forming a sealing joint extending into the through openings of the electrical insulating support and connecting two interconnecting plates through the through openings.

[0015] The reaction fluids referred to are the fluids supplied to the electrodes and the fluids drained from the electrodes. Depending on the operating mode (fuel cell or electrolyzer) of the electrochemical reactor, these include high-temperature steam, dihydrogen, dioxygen, etc.

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

[0017] In the sealing and insulation assemblies thus produced, the electrical insulating support and the fusible seal cooperate to form a seal which adheres to the interconnecting 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 interconnecting 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 a laboratory or small-batch production process, involving meticulous and difficult-to-repeat manipulations. The invention enables the 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 capacity of solid oxide electrochemical reactors, specifically by enabling an increase in the size of the stacks. The invention is thus particularly well-suited to current objectives of increasing the number of layers in reactors, leading to an increase in stack height and greater complexity in controlling their fabrication. Managing height variations is indeed particularly critical during reactor manufacturing.

[0021] The expected performance of future solid oxide electrochemical reactors tends to necessitate the implementation of tall stacks that can include hundreds of interconnecting plates. Furthermore, the cumulative length of the sealing barriers (i.e., the sum of the sealing joint lengths) for each stage of an electrochemical reactor can be on the order of 2 meters. In the case, for example, of a 20 kW power reactor consisting of 75 stages, the cumulative length of the sealing joints reaches approximately 150 m.

[0022] The invention allows for a reduction in the overall height of the stacks before they are placed under pressure. Lowering the stack height before pressure also results in a reduction of the stack's lowering stroke during clamping, thus reducing the complexity of the necessary guides and the risk of stack sagging.

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

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

[0025] - prior to the step of placing a second layer on the electrically insulating support of fusible joint, the process includes a step of depositing said second bed of fusible joint on a second interconnection plate, and, in the step of placing a second bed of fusible joint on the electrical insulating support, the assembly formed of the second interconnection plate and the second bed of fusible joint is placed on the electrical insulating support;

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

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

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

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

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

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

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

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

[0034] - in the stage of manufacturing the electrical insulating support, the through openings are arranged in discontinuous grooves arranged along joint lines;

[0035] - in the step of manufacturing the electrical 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 manufacturing the electrical insulating support, said sheet of material electrically insulating is further pierced with at least one lateral window intended for the passage of the transverse channel for the circulation of reaction fluids, the joint lines being arranged around this lateral window;

[0037] - in the stage of manufacturing the electrical insulating support, several joint lines parallel lines are arranged side by side;

[0038] - said parallel joining lines are formed of discontinuous grooves which include discontinuities arranged in a staggered pattern;

[0039] - the electrical insulating support comprises a one-piece frame;

[0040] - in the step of carrying out an alternating stacking 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 fusible joint interstitial cord, and the second fusible joint bed includes: a glass powder, or glass-ceramic, or ceramic; a solvent; and a binder. PRESENTATION OF THE FIGURES

[0042] Other features and advantages of the invention will become apparent from the following non-limiting description, with reference to the accompanying drawings in which:

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

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

[0045] - [Fig. 3] is a detail view of a sealing and insulation assembly installed work in the process 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 process according to the invention.

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

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

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

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

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

[0052] Fig. 1 illustrates an electrical insulating support 1 intended to form one of the sealing and insulation assemblies of the electrochemical reactor according to the invention.

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

[0054] In the present example, the electrically insulating support 1 comprises a one-piece frame which has a general square frame shape, intended to be placed in a stack of electrochemical cells and interconnecting plates which are themselves square. The electrical insulating support 1 in this particular example forms a frame with a central window 3 designed for positioning an electrochemical cell. This assembly will be sandwiched between two interconnecting plates to form the basic stacking pattern.

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

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

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

[0058] Several joint lines can be arranged in parallel and side by side, as is the case for the joint lines between each side window 4 and the edge of the electrical insulating support 1. In this case, the discontinuities in the grooves are preferably staggered in order to lengthen the potential leakage path between two adjacent joint lines, thereby improving the sealing of the finished stack. The material of the electrical insulating support 1 may therefore have a certain porosity, which will not impair the sealing once gaskets are installed in the discontinuous grooves forming the through openings 2.

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

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

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

[0062] The interconnecting plates 6 in this example comprise three layers 6A, 6B, 6C. In the view of [Fig. 2], where only one electrochemical cell 5 is shown: - a first outer 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 outer 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 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 fluids produced by the reaction (water vapor, dioxygen, dihydrogen, etc.).

[0064] In the example illustrated in [Fig.2], layer 6A of the lower interconnecting plate 6 manages the reaction fluids for the lower electrode 10, while layer 6B of the upper interconnecting 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, preventing the fluids from mixing. In this example, a sealing gasket 11 is arranged between the solid electrolyte layer 8 and the interconnecting plate 6 below, to separate the flows specific to each electrode.

[0066] The electrochemical reactor further includes a sealing and insulation assembly 12 enabling a seal to be created between the interconnecting plates 6.

[0067] This sealing and insulation assembly 12 is formed from the electrical insulating support 1 of [Fig.l], associated with a sealing gasket 13 which extends into the through openings 2 of the electrical 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 electrical 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 interconnecting plate 6. This figure thus presents the sealing barrier formed by the method according to the invention.

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

[0070] The arrangement of the through openings 2, implemented here as joint lines along which discontinuous grooves extend, ensures the physical integrity of the electrical insulating support 1, which remains a single piece, thus ensuring proper positioning of all the joints. The joint lines can be straight lines, curved lines, dashed lines, wavy lines, or any other shape suitable for a particular application.

[0071] The process according to the invention comprises a first step of making the electrical insulating support 1 of [Fig. 1], 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 of the mica sheet, laser cutting, punching, milling, etc., or even molding or additive manufacturing for suitable materials.

[0072] The next step of the process consists of depositing at least a first bed of fusible seal 20 on an interconnecting plate 6.

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

[0074] The fusible joint bed 20 can be formed by depositing extruded paste. The entire fusible joint bed 20 can thus be produced by extrusion and then applied to the interconnecting plate. According to another embodiment, the fusible joint bed 20 can, for example, be deposited as paste by a special extrusion device, such as a robotic arm equipped with a syringe. In an advantageous embodiment, the fusible joint bed 20 is formed by this extrusion device depositing adjacent joint beads. These beads can be straight, placed side by side and touching, for example, beads with a width of approximately 1 to 2 mm. In the figures, the undulating upper surface of the fusible joint bed 20 illustrates this formation of adjacent joint beads.The fusible joint bed 20 can also be deposited in a single pass, for example by an extrusion method adapted to directly supply the fusible joint in sheets or plates. Any other suitable process for depositing a fusible joint bed can be used, 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 that is impermeable to reaction fluids and electrically insulating. Preferably, this material is glass-based or glass-ceramic. It can also be based on other materials, such as a suitable ceramic or 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 agglomerates into molten glass, forming a joint capable of adhering to the interconnecting 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 process is illustrated in the perspective view of [Fig. 6] and the corresponding front view of [Fig. 7]. This step consists of placing the electrical insulating support 1 on the joint bed 20.

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

[0079] The perspective view of [Fig.8] and its corresponding front view illustrate the next step of the process, 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 fusible interstitial bead 21 is preferably made of the same material as the fusible bed 20 and is deposited in paste form by an extrusion device adapted to fill the volume of the through-holes. At least one fusible interstitial bead 21 is deposited in the through-holes 2, it being understood that as many of these interstitial beads as necessary can be deposited, so as preferably to fill the entire volume of the through-holes 2. The fusible interstitial bead 21 can be deposited in one or more passes.

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

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

[0083] A subsequent step in the process consists of placing a second bed of fusible seal 22 on the electrically insulating support 1. This step is illustrated in [Fig. 10] (view in perspective) and to [Fig.1 1] (front view).

[0084] In the present example, the second bed of fusible seal 22 is deposited together with an upper interconnecting plate 6. This allows the positioning of the second bed of fusible seal 22 and the alternating stacking of an electrochemical cell 5 with the two interconnecting plates 6 that enclose it to be accomplished in a single operation. To do this, the second bed of fusible seal 22 will have been previously deposited on this upper interconnecting plate 6, in the same way that the first bed of fusible seal 20 was deposited on its interconnecting plate 6 (as illustrated in Figures 4 and 5). The assembly formed by this upper interconnecting plate and its second bed of fusible seal 22 is then placed (with the face containing the second bed of fusible seal 22 facing up) on the electrically insulating support 1, the through-holes of which 2 are filled with the interstitial bonding cords 21.

[0085] This operation leads to the assembly of figures 10 and 11. The total volume of the first bed of fusible joint 20, the interstitial cords of fusible joint 21, and the second bed of fusible joint 22 are determined in order to fill all the through openings 2, and to form a joint layer between the electrical insulating support 1 and each interconnecting plate 6. This volume can be calculated as accurately as possible, which implies that only a small excess thickness will need to be flattened during the melting of the joint, drastically reducing the height travel of the stack in the next step.

[0086] Preparing the fusible joint in three layers also eliminates the need for any shaping or rectification of the fusible joint elements, which may have been necessary in the prior art, such as cutting or flattening the bumps left by the paste deposition operation, etc.

[0087] The next step of the process consists of alternating the stacking of electrochemical cells 5 and interconnecting plates 6 to create the electrochemical reactor, with the electrical insulating support 1 positioned at the locations provided for the sealing and insulation assemblies 12. As before, for clarity, only one elementary pattern of the stacking has been illustrated (between two interconnecting plates 6), it being understood that the stacking may include as many of these patterns as necessary. The invention allows for stacks of significant height, for example, on the order of 80 layers of electrochemical cells 5.

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

[0089] Alternating stacking can also be achieved by pre-preparing sets of interconnecting plates 6 coated on both sides with a bed of fusible seal (a first bed of fusible seal 20 on one of its faces and a second bed of fusible seal 22 on the other of its faces).

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

[0091] From this stacking assembly, the sealing within the electrochemical reactor being manufactured will be able to be achieved.

[0092] The alternating stacking assembly of figures 10 and 11 is preferably carried out in a press which advantageously includes guiding means 18 along the stacking direction D, for each element of the stack (the guiding means 18 are schematically represented by axis lines on the [Fig. 11]).

[0093] The next step in the process consists of pressing said alternating stack along the stacking direction D and bringing it to a melting temperature of the material of the various fusible joints. For each layer, the melting temperature is higher than the melting point of the first bed of fusible joint 20, the interstitial bond beads 21, and the second bed of fusible joint 22, so as to achieve the melting of the latter.

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

[0095] The different portions of the fusible joint become homogenized and thus form a sealing joint 13 by agglomerating through the through-holes 2 under the effect of the press, and by adhering to the interconnecting plates 6 located opposite these through-holes. A sealing joint 13 is thus formed, extending into the through-holes 2 of the electrical insulating support 1, and connecting two interconnecting plates 6 through the through-holes 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 rest 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 electrical insulating support, and therefore of the resulting sealing and insulation assembly 12, may vary and, for example, consist only of linear barriers. sealing elements are arranged at appropriate locations around each electrochemical cell 5, rather than in a frame shape as in the illustrated example. Similarly, sealing and insulation assemblies 12 can be provided for any type of sealing required between two interconnecting plates 6, other than seals around the transverse channels 7 and the seal to the outside of the reactor.

[0098] Furthermore, the material of the three fusible joint layers (first fusible joint layer 20, fusible joint beads 21, and second fusible joint layer 22) may exhibit variations, although the three layers are intended to agglomerate upon melting. The particle size of the glass powder, or the viscosity of the product, may, for example, differ from one layer to another.

Claims

Demands

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

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

3. A method according to any one of claims 1 or 2, characterized in that the first fusible joint bed (20) is made by deposition of extruded paste.

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

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

6. A method according to any one of the preceding claims, characterized in that the second fusible joint bed (22) is made by deposition of extruded paste.

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

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

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

10. A method according to any one of the preceding claims, characterized in that the interstitial cord of fusible joint (21) is flush with the surface of the electrical insulating support (1), on each of its faces.

11. A method according to any one of the preceding claims, characterized in that, in the step of making the electrical insulating support (1), the through openings (2) are arranged in discontinuous grooves arranged along joint lines.

12. A method according to claim 11, characterized in that, in the step of making 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). A method according to any one of claims 11 or 12, characterized in that, in the step of making the electrical 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 the circulation of reaction fluids, the joining lines being arranged around this lateral window (4). A method according to any one of claims 11 to 13, characterized in that, in the step of making the electrical insulating support (1), several parallel joint lines are arranged side by side. Method according to claim 14, characterized in that said parallel joining lines are formed of discontinuous grooves which have discontinuities arranged in a staggered pattern. Method according to any one of the preceding claims, characterized in that the electrical insulating support (1) comprises a one-piece frame. A method according to any one of the preceding claims, characterized in that, in the step of carrying out an alternating stacking of electrochemical cells (5) and interconnecting plates (6), the stacking is carried out in a press comprising guiding means (18) along the stacking direction (D). A method according to any one of the preceding claims, characterized in that the first bed of fusible joint (20), the interstitial bead of fusible joint (21), and the second bed of fusible joint (22) comprise: a glass powder, or a glass-ceramic powder, or a ceramic powder; a solvent; and a binder.

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