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

Abstract

A method for manufacturing a solid oxide electrochemical reactor, comprising the following steps: – producing an electrically insulating support (1) with through-holes (2); – depositing at least one fusible seal bead (15) onto a selected element from the group consisting of the interconnecting plates (6) and the electrically insulating support (1); – performing a hardening operation on the fusible seal bead (15); – compressing the fusible seal bead (15) along the stacking direction and plastically deforming it; – pressing an alternating stack and heating it to the melting temperature of the fusible seal bead (15), so that the fusible seal bead (15) extends into the through-holes (2) of the electrically insulating support (1) and forms a seal connecting two interconnecting plates (6) through these through-holes (2). Figure for the abstract: Fig. 9

Description

Title of the invention: Method for manufacturing a solid oxide electrochemical reactor comprising 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) to form 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 electrical connection of the cells. Electrical insulation between interconnecting plates is therefore also a critical point, to prevent 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 arranged between the interconnecting plates.

[0014] This process comprises the following steps: - creation of an electrical insulating support comprising a sheet of electrically insulating material pierced with through openings; - apply at least one bead of electrically insulating fusible sealant to an element selected from the group consisting of the interconnecting plates and the electrically insulating support; - perform a hardening operation on the fusible joint bead; - compress the fusible joint cord along the stacking direction, and deform it plastically; - to create an alternating stack of electrochemical cells and interconnecting plates, and to place the electrical insulating support between two interconnecting plates; - press said alternating stacking along the stacking direction, and bring it to a melting temperature of the fusible joint bead, so that the fusible joint bead extends into the through openings of the electrical insulating support, and forms a sealing joint connecting two interconnecting plates through these 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 quality and the required 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 pressing, in combination with the creation of bearing surfaces of calibrated shape and height on the fusible seal beads. Lowering the stack height before pressing 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] - in the stage of manufacturing the electrical insulating support, the through openings are arranged in discontinuous grooves arranged along joint lines;

[0026] - 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;

[0027] - 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;

[0028] - in the stage of manufacturing the electrical insulating support, several joint lines parallel lines are arranged side by side;

[0029] - said parallel joining lines are formed of discontinuous grooves which include discontinuities arranged in a staggered pattern;

[0030] - the electrical insulating support comprises a one-piece frame;

[0031] - in the step of depositing at least one fusible seal bead, seal beads Fuses are placed on the edge of each through opening;

[0032] - in the step of compressing the fusible seal cord, all the seal cords fuses are calibrated to the same height;

[0033] - in the step of compressing the fusible joint cord, the compression is carried out by a press comprising jaws extending along a flat surface substantially perpendicular to the stacking direction;

[0034] - in the step of compressing the fusible joint cord, the compression is carried out by applying a predetermined force;

[0035] - in the step of compressing the fusible seal cord, the compression is carried out by applying a predetermined displacement;

[0036] - in the step of compressing the fusible joint cord, the joint cord fuse is plastically deformed to present planar spans substantially perpendicular to the stacking direction;

[0037] - in the step of carrying out an alternating stacking of electrochemical cells and interconnecting plates, the stacking is carried out in a press having guiding means following the stacking direction, the step of compressing the fusible joint bead being carried out in this same press;

[0038] - the fusible joint cord comprises: a glass powder, or a glass-ceramic powder, or ceramic; a solvent; and a binder;

[0039] - in the step of depositing at least one fusible seal bead, the seal bead fuse is placed on an interconnecting plate; and in the step of compressing the fusible joint cord, the compression is carried out on the assembly formed by this interconnecting plate and the fusible joint cord; and in the step of carrying out an alternating stacking of electrochemical cells and interconnecting plates, the fusible joint cord is brought into contact with the electrical insulating support;

[0040] - in the step of depositing at least one fusible seal bead, the seal bead fuse is placed on the electrical insulating support; and in the step of compressing the fusible joint cord, the compression is carried out on the assembly formed by this electrical insulating support and the fusible joint cord; and in the step of carrying out an alternating stacking of electrochemical cells and interconnecting plates, the fusible joint cord is brought into contact with an interconnecting plate;

[0041] - in the step of depositing at least one fusible seal bead, the seal bead The fuse is deposited in the areas between the joint lines. 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 cells electrochemical 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], and [Fig.1 1] illustrate steps of the process according to a first embodiment of the invention;

[0047] - Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18 and Fig. 19 illustrate the steps of the process according to a second embodiment of the invention.

[0048] Similar and common elements in the various embodiments bear the same reference numbers to the figures. DETAILED DESCRIPTION

[0049] 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).

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] In the present example, the electrical insulating support 1 comprises a one-piece frame that has a general square frame shape, intended to be placed in a stack of electrochemical cells and interconnecting plates that are themselves square. The electrical 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 interconnecting plates to form the basic unit of the stack.

[0056] 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.

[0057] 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.

[0058] 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].

[0059] Several joint lines can be arranged in parallel and side by side, as is the case with 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, to improve the sealing of the finished stack. The material electrical insulating support 1 may therefore exhibit some porosity, which will not affect the sealing once seals are put in place in the discontinuous grooves constituting the through openings 2.

[0060] Figure [Fig. 2] is a partial cross-sectional view illustrating an elementary motif of the stacking of the electrochemical reactor, 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.

[0061] Each electrochemical cell 5 comprises a solid electrolyte layer 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.

[0062] 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 flow from one interconnecting plate 6 to the other.

[0063] The interconnecting plates 6 of this example comprise three layers 6A, 6B, 6C. On the view of [Fig.2], where only an electrochemical cell 5 is illustrated: - a first outer layer 6A is provided with reaction fluid distribution channels for the electrochemical cell which is located above the interconnecting 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.

[0064] 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.).

[0065] 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 the Layer 6B of the top interconnection plate 6 handles the reaction fluids for the top electrode 9.

[0066] 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.

[0067] The electrochemical reactor further includes a sealing and insulation assembly 12 enabling a seal to be created between the interconnecting plates 6.

[0068] This sealing and insulation assembly 12 is formed from the electrical insulating support 1 of [Fig.1], 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] The process according to the invention includes 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 necessary, 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.

[0073] The next step of the process consists of depositing at least one fusible joint bead 15 onto the electrically insulating support 1. The volume of fusible joint bead 15 deposited is determined with the aim of filling all through openings 2, and adhering to the interconnecting plates 6 on either side of each through opening 2.

[0074] Figure 4 illustrates in perspective the result of this fusible joint bead deposition and [Fig.5] is the corresponding front view.

[0075] In the present example, fusible joint cords 15 are deposited on each face of the electrical insulating support 1, for better distribution of the joint.

[0076] In this example, the fusible joint cords 15 are deposited on the areas between the joint lines, i.e. on the solid parts of the electrical insulating support 1 which are located between the joint lines of the through openings 2. The fusible joint cords 15 are therefore deposited at the edge of each through opening 2. Each through opening 2 is thus bordered by fusible joint cords 15.

[0077] The fusible sealant beads 15 are, for example, deposited in paste form by an extrusion device, such as a robotic arm equipped with a syringe. Any other suitable process for depositing paste beads may be used, for example spraying, additive manufacturing, strip sealing, etc.

[0078] In the present example, these fusible joint cords 15 have a width of approximately 1 to 2 mm.

[0079] The material constituting the deposited fusible joint beads 15 is a material having a melting point beyond which it will form a seal that is leak-proof against 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.

[0080] In the present example, the fusible joint bead consists of a mixture of glass powder, an ethanol-type solvent, and a terpineol-type binder. This joint bead 15 is fusible because, when the melting point of the glass powder is reached, the glass powder agglomerates into molten glass, forming the joint extending into the through-holes 2 of the electrical insulating support 1. The glass powder in this example is ground glass, with an average particle size between 30 µm and 0.1 µm.

[0081] The next step of the process, after the deposition of the fusible joint beads 15, consists of carrying out a hardening operation of the fusible joint beads 15.

[0082] In the present example, given the material chosen for the fusible joint 15, this curing step can be carried out by evaporating the solvent (here, ethanol) through a drying operation. This drying operation can be carried out by any suitable means, possibly including ventilation, temperature increase, etc.

[0083] The drying time corresponding to the evaporation of the most volatile solvents depends on the amount of fusible sealant deposited and the geometry of the deposited bead. In practice, the external surface of fusible joint beads can form a rigid crust within minutes, and complete drying of the bead can take several hours. A drying time of 24 hours at room temperature can be implemented, for example.

[0084] Alternatively, this curing step can be carried out by any other means suitable for the material of the fusible joint. For example, exposure to UV rays in the case of a fusible joint containing a UV-curable element, or by allowing a resting period in the case of a fusible joint containing a curable two-component mixture.

[0085] Thanks to this step, the fusible joint cords 15 undergo an increase in their hardness, and retain the same shape as in figures 4 and 5. The assembly formed from the electrical insulating support 1 and the hardened fusible joint cords 15 is then manipulable.

[0086] The next step of the process, illustrated in the front view of [Fig.6], consists of putting this assembly under pressure, and compressing the fusible joint cords 15 along the stacking direction D.

[0087] Fig. 6 schematically illustrates a press comprising jaws 16 which extend along a flat surface the size of the electrical insulating support 1 and substantially perpendicular to the stacking direction, and which are adapted to compress all the fusible joint cords 15. Preferably, the jaws 16 are as perfectly perpendicular as possible to the stacking direction.

[0088] The result of the compression operation of the fusible joint cords 15 is illustrated in the front view of [Fig.7] and in the perspective view of [Fig.8]. The fusible joint cords 15 have been plastically deformed, i.e., they retain the acquired shape even after removal from the press.

[0089] The fusible joint cords 15 thus deformed have a height H (corresponding to their dimension along the compression direction D) which is calibrated by the compression step.

[0090] Preferably, the compression can be calibrated by predetermining the pressure applied by the press. The compression step of the fusible joint beads 15 is then carried out by applying a predetermined force. In this example, given the dimensions of the stack elements, this clamping force can be between 1 kN and 1000 kN, and preferably between 20 and 100 kN. "Compression-crushing force" charts can be used for the different geometries of interest.

[0091] All fusible joint cords 15 are thus calibrated to the same height H by cold pressing.

[0092] According to a particularly advantageous example, the compression stroke applied to each fusible joint bead 15 is equal to the tolerance related to the deposition operation of the fusible joint beads 15, multiplied by a factor. For example, this compression stroke can be equal to three times (multiplication factor of 3) 50 pm, or 150 pm, in the case where the tolerance related to the deposition operation of the fusible joint beads 15 is 50 pm. This ensures that all the fusible joint beads 15 will be effectively compressed and calibrated in height.

[0093] The tolerance related to the operation of depositing the fusible joint beads 15 depends on the process and the equipment used to carry out the deposit, and corresponds to the possible range of differences in joint height actually deposited for the same instruction.

[0094] Alternatively, the compression step can be carried out according to other criteria. For example, the compression step of the fusible joint cords 15 is carried out by compression consisting of applying a predetermined displacement, i.e. by calibrating the displacement of the jaws 16 by a predetermined value, calibrating the predetermined height H for each fusible joint cord 15.

[0095] The compression step also makes it possible to do without any shaping or rectification operation of the fusible joint cords 15, which could be necessary in the prior art, such as cutting or flattening the bumps left by the paste deposition operation, etc.

[0096] According to a particularly advantageous example, the compression step also makes it possible to form a planar surface 17 on the fusible joint cords 15, preferably perpendicular to the stacking direction D, which promotes the stability of the alternating stack, especially if the latter includes a large number of electrochemical cells 5 and interconnecting plates 6.

[0097] The next step of the process is illustrated in the perspective view of [Fig. 9] and its front view in [Fig. 10]. This step consists of creating the alternating stacking of electrochemical cells 5 and interconnecting plates 6, in order to construct the electrochemical reactor, with the electrical insulating support 1 positioned at the locations provided for the sealing and insulation assemblies 12. As before, for the sake of clarity, only one elementary pattern of the stacking has been illustrated (between two interconnecting plates 6), it being understood that the stacking comprises 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. Furthermore, in the views of Figures 9 and 10, only a portion of the interconnecting plates 6 and the electrical insulating support 1 (with its dried and compressed fusible seal cords 15) has been shown.The other portions of . The stack, comprising the electrochemical cells 5, known from other sources, have not been illustrated.

[0098] According to the present embodiment, the installation of the electrical insulating support 1 brings with it the fusible joint cords 15 that it carries. Generally, an electrical 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 consisting of the electrical insulating support 1 and the fusible joint cords 15 is arranged between each pair of interconnecting plates 6.

[0099] From this stacking assembly, the sealing within the electrochemical reactor being manufactured will be able to be achieved.

[0100] The alternating stacking assembly of figures 9 and 10 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. 10]).

[0101] The next operation of the process consists of pressing said alternating stack along the stacking direction D and bringing it to a melting temperature of the fusible joint cords 15. This melting temperature is higher than the melting point of the fusible joint cords 15, so as to obtain the melting of the latter.

[0102] In the present example, the melting temperature of the fusible joint cords 15 is between 850 °C and 1000 °C (for an electrochemical reactor operating for example at 800 °C), and is in any case lower than the operating temperature intended for the electrochemical reactor.

[0103] During this step, the fusible seal cords 15 melt and deform under the effect of the applied pressure.

[0104] The fusible seal thus forms a sealing seal 13 by spreading into the through openings 2 under the effect of the press, and adhering to the interconnecting plates located opposite these through openings. A sealing joint 13 is thus formed, extending into the through openings 2 of the electrical insulating support 1, and connecting two interconnecting plates 6 through the through openings 2, as illustrated in [Fig. 11].

[0105] 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.

[0106] Figures 12 to 19 illustrate a second embodiment of the manufacturing process according to the invention in which the fusible joint cords 15, rather than to be deposited on the electrical insulating support 1, are alternatively deposited on the interconnection plates 6.

[0107] According to this second embodiment, after a first step of making the electrical insulating support 1, pierced with through openings 2, a second step consists of depositing at least one fusible joint bead 15 on each interconnection plate 6. The perspective view of [Fig.12], and its front view of [Fig.13], illustrate the deposition of the fusible joint beads 15 on one face of an interconnection plate 6. The deposition of the fusible joint beads 15 can also take place on both faces of each interconnection plate 6.

[0108] The deposition method and the deposited material are the same as in the first embodiment. Similarly, the volume of fusible joint bead 15 deposited is determined in order to fill all the through openings 2, and to adhere to the interconnecting plates 6 on either side of each through opening 2 of the electrical insulating supports 1.

[0109] The next step of the process consists of carrying out the operation of hardening the fusible joint beads 15, in this example by evaporation of a solvent through a drying operation of the fusible joint beads 15 or any other suitable method, as for the first embodiment.

[0110] The next step of the process consists of putting this assembly, consisting of an interconnecting plate 6 with its fusible joint cords 15, under pressure, and compressing the fusible joint cords 15 along the stacking direction D, in the same way as in the first embodiment.

[0111] The result of the compression operation of the fusible joint cords 15 is illustrated in the front view of [Fig. 14] and in the perspective view of [Fig. 15]. The fusible joint cords 15 thus plastically deformed have a calibrated height and, in this example, a planar span 17.

[0112] The next step of the process is illustrated in the perspective view of [Fig. 16] and consists of placing the electrical insulating support 1 on the interconnecting plate 6 fitted with its dried and compressed fusible joint cords 15, in order to initiate the formation of an alternating stack with an electrochemical cell 5 (not visible in the partial view of [Fig. 16]), an interconnecting plate 6, and the electrical insulating support 1 intended to form the sealing and insulation assembly 12 at the required locations.

[0113] The alternating stacking of electrochemical cells 5 and interconnecting plates 6 is continued, with the addition of another interconnecting plate 6 similarly equipped with dried and compressed fusible joint cords 15. The perspective view of [Fig. 17] and the corresponding front view of [Fig. 18] illustrates an elementary stacking pattern, in partial view, with an electrically insulating support 1 between two interconnecting plates 6.

[0114] From this stacking assembly, produced in a press with guiding means along the stacking direction D, the sealing within the electrochemical reactor being manufactured can be achieved in the same way as in the first embodiment, with the press clamping said alternating stacking along the stacking direction D, at the melting temperature of the fusible seal beads 15, so that the fusible seal thus forms a sealing gasket 13 by spreading into the through openings 2 under the effect of the press, and by adhering to the interconnecting plates 6 located opposite these through openings 2. A sealing gasket 13 is thus formed, by extending into the through openings 2 of the electrical insulating support 1, and by connecting two interconnecting plates 6 through the through openings 2, as illustrated in [Fig. 19].

[0115] This second embodiment makes it possible to limit the handling of the electrical insulating support 1 which can be fragile, this is the case for example when it is made of mica, by transferring certain handling to the interconnection plates 6. This second embodiment also makes it possible to mechanically preserve the electrical insulating support 1, in particular when it is compressible, by avoiding a compression step.

[0116] 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 sealing barriers arranged at suitable locations around each electrochemical cell 5, rather than in the form of a frame as in the illustrated example. Similarly, the sealing and insulation assemblies 12 may be provided for any type of sealing required between two interconnecting plates 6, other than the seals around the transverse channels 7 and the seal to the outside of the reactor.

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) disposed between the interconnecting plates (6); this method comprising the following steps: - making an electrically insulating support (1) comprising a sheet of electrically insulating material pierced with through openings (2);- depositing at least one electrically insulating fusible joint bead (15) on an element selected from the group consisting of the interconnecting plates (6) and the electrically insulating support (1); this process being characterized in that it comprises the following steps: - carrying out a hardening operation of the fusible joint bead (15); - compressing the fusible joint bead (15) along the stacking direction (D), and plastically deforming it; - carrying out an alternating stacking of electrochemical cells (5) and interconnecting plates (6), and placing the electrically insulating support (1) between two interconnecting plates (6);- press said alternating stacking along the stacking direction (D), and bring it to a melting temperature of the fusible joint bead (15), so that the fusible joint bead (15) extends into the through openings (2) of the electrical insulating support (1), and forms a sealing joint (13) connecting two interconnecting plates (6) through these through openings (2).;

2. Method according to claim 1, 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.

3. Method according to claim 2, characterized in that, in the step of making the electrical insulating support (1), said sheet of electrically insulating material is further pierced with a central window (3) for the positioning of an electrochemical cell (5), the joining lines being arranged around this central window (3).

4. A method according to any one of claims 2 or 3, 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).

5. A method according to any one of claims 2 to 4, characterized in that, in the step of making the electrical insulating support (1), several parallel joining lines are arranged side by side.

6. A method according to claim 5, characterized in that said parallel joining lines are formed of discontinuous grooves which have discontinuities arranged in a staggered pattern.

7. A method according to any one of the preceding claims, characterized in that the electrically insulating support (1) comprises a one-piece frame.

8. A method according to any one of the preceding claims, characterized in that, in the step of depositing at least one fusible seal bead (15), fusible seal beads (15) are deposited on the edge of each through opening (2).

9. Method according to claim 8, characterized in that, in the step of compressing the fusible seal cord (15), all fusible seal cords (15) are calibrated to the same height (H).

10. A method according to any one of the preceding claims, characterized in that, in the step of compressing the fusible joint cord (15), the compression is carried out by a press comprising jaws (16) extending along a flat surface substantially perpendicular to the stacking direction (D).

11. A method according to any one of the preceding claims, characterized in that, in the step of compressing the fusible joint cord (15), the compression is achieved by applying a predetermined force.

12. A method according to any one of claims 1 to 10, characterized in that, in the step of compressing the fusible joint cord (15), the compression is carried out by applying a predetermined displacement.

13. A method according to any one of the preceding claims, characterized in that, in the step of compressing the fusible joint cord (15), the fusible joint cord (15) is plastically deformed to present planar bearing surfaces (17) substantially perpendicular to the stacking direction (D).

14. 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), the step of compressing the fusible joint bead (15) being carried out in this same press.

15. A method according to any one of the preceding claims, characterized in that the fusible joint cord (15) comprises: a glass powder, or a glass-ceramic powder, or a ceramic powder; a solvent; and a binder.

16. A method according to any one of the preceding claims, characterized in that: in the step of depositing at least one fusible joint cord (15), the fusible joint cord (15) is deposited on an interconnecting plate (6); and in the step of compressing the fusible joint cord (15), the compression is carried out on the assembly formed by this interconnecting plate (6) and the fusible joint cord (15); and in the step of carrying out an alternating stacking of electrochemical cells (5) and interconnecting plates (6), the fusible joint cord (15) is brought into contact with the electrical insulating support (1).

17. A method according to any one of claims 1 to 15, characterized in that: in the step of depositing at least one fusible joint cord (15), the fusible joint cord (15) is deposited on the electrically insulating support (1); and in the step of compressing the fusible joint cord (15), the compression is carried out on the assembly formed by this electrically insulating support (1) and the fusible joint cord (15); and in the step of creating an alternating stack of electrochemical cells (5) and interconnecting plates (6), the cord of 19 fusible joint (15) is brought into contact with an interconnection plate (6).

18. A method according to claim 17 when it depends on claim 2, characterized in that, in the step of depositing at least one fusible joint bead (15), the fusible joint bead (15) is deposited on the areas between the joint lines.

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