Method for manufacturing a solid oxide electrochemical reactor comprising an assembled electrically insulating support

Abstract

A method for manufacturing a solid oxide electrochemical reactor, comprising the following steps: – producing a plurality of peripheral strips (26); – making through-joint openings in each peripheral strip (26); – forming an electrically insulating support by assembling several of said peripheral strips (26) onto a first interconnecting plate (6); – creating an alternating stack of electrochemical cells (5) and interconnecting plates (6); – pressing said alternating stack along the stacking direction and heating it to a fusible joint melting temperature, such that the fusible joint extends into the through-joint openings of the electrically insulating support and forms a seal connecting two interconnecting plates (6) through these through-joint openings. Figure for the abstract: Fig. 4

Description

Title of the invention: Method for manufacturing a solid oxide electrochemical reactor comprising an assembled electrically insulating support 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 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. Statement 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, these sealing and insulation assemblies each include an electrical insulating support pierced with through jointing openings and sealing joints connecting two interconnection plates through these through jointing openings.

[0014] This process comprises the following steps: - produce a plurality of peripheral strips from a sheet of electrically insulating material, these peripheral strips each having two longitudinal ends equipped with junction zones; - to make a lateral window in at least one of the peripheral bands, this lateral window being adapted to form a passage for said transverse channel; - make through jointing openings in each peripheral strip; - to form one of said electrical insulating supports by assembling several of said peripheral strips on a first interconnection plate at the level of their junction areas, forming a frame which delimits a central window adapted to receive one of said electrochemical cells; - to create an alternating stack of electrochemical cells and interconnecting plates, comprising at least: said first interconnecting plate with the corresponding electrical insulating support, formed of said assembly of peripheral strips; one of said electrochemical cells disposed in the central window of the electrical insulating support; an electrically insulating fusible joint in contact with the electrical insulating support; and a second interconnecting plate; - press said alternating stacking along the stacking direction, and bring it to a melting temperature of the fusible joint, so that the fusible joint extends into the through-jointing openings of the electrical insulating support, and forms a sealing joint connecting two interconnecting plates through these through-jointing 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 needed for the future, in a context of energy source diversification.

[0020] The invention improves the quality of sealing and electrical insulation barriers, and simplifies the assembly of stacks.

[0021] The invention thus allows joint optimization of the manufacturing process of solid oxide electrochemical reactors, and a reduction of costs by optimizing the use of insulating material sheets, and by limiting the waste of material.

[0022] The method according to the invention may include the following additional features, alone or in combination:

[0023] - the peripheral bands are generally rectangular or trapezoidal in shape, with junction zones adjacent to at least two corners of said shapes;

[0024] - the method includes a preliminary step of depositing a first bed of fusible seal electrically insulating on the first interconnecting plate, and the assembly of several of said peripheral strips is carried out on said first bed of joint;

[0025] - the first bed of fusible sealant is deposited in the form of a continuous strip of sealant fuse;

[0026] - the first bed of fusible sealant is deposited in the form of discontinuous sealant beads fuse;

[0027] - the step of carrying out an alternating stacking of electrochemical cells and plates interconnection is achieved by reproducing an elementary pattern, by depositing a bed of electrically insulating fusible joint on the face of the second interconnection plate that is opposite the first interconnection plate;

[0028] - the method includes a preliminary step of depositing a bed of electrical fusible seal trically insulating on the second interconnecting plate, and, during the step of making an alternating stack of electrochemical cells and interconnecting plates, the second interconnecting plate is arranged on the first interconnecting plate so that this bed of fusible joint comes into contact with the peripheral strips;

[0029] - after the step of forming one of said electrically insulating supports, the openings tra The jointing slopes of the peripheral strips are lined with electrically insulating fusible sealant;

[0030] - during the step of forming one of said electrically insulating supports, the peri-bands spheres are assembled by complementary joining pieces in the joining areas;

[0031] - the joining pieces fit together in the joining areas;

[0032] - the connecting pieces are also produced during the step of producing a plurality of peripheral strips, from the same sheet of electrically insulating material;

[0033] - the junction zones have complementary interlocking shapes;

[0034] - the step of forming one of said electrically insulating supports is carried out by the assembly of the peripheral strips around a template the size of the central window, this template being placed on the first interconnection plate;

[0035] - in the step of producing a plurality of peripheral strips, four peripheral strips Identical spheres are produced from a sheet of insulating material;

[0036] - in the step of forming one of said electrically insulating supports, the openings tra jointing slopes are arranged in discontinuous grooves arranged along jointing lines;

[0037] - the joint lines are arranged around the side window;

[0038] - the jointing lines are arranged around the central window;

[0039] - during the step of carrying out an alternating stacking of electrochemical cells and interconnection plates, the stacking is carried out in a press, and the step of forming one of said electrical insulating supports by assembling several of said peripheral strips onto a first interconnection plate is carried out in this same press;

[0040] - the fusible seal comprises: a glass powder, or a glass-ceramic powder, or a ceramic; a solvent; and a binder. PRESENTATION OF FIGURES

[0041] Other features and advantages of the invention will become apparent from the following non-limiting description, with reference to the accompanying drawings in which:

[0042] - [Fig. 1] is a perspective view of an electrically insulating support implemented in the process according to the invention;

[0043] - [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;

[0044] - [Fig. 3] illustrates peripheral strips used in the process according to the invention;

[0045] - Figure 4 illustrates in perspective the formation of an electrically insulating support in the framework of the process according to the invention;

[0046] - [Fig.5] illustrates the electrical insulating support constituted in [Fig.4];

[0047] - [Fig.6] illustrates a variant of the peripheral band;

[0048] - [Fig.7] and [Fig.8] illustrate another variant of peripheral strip;

[0049] - the [Fig.9] illustrates the removal of a fusible seal in a peripheral strip;

[0050] - Figure 10 illustrates the application of a bed of fusible sealant onto a plate interconnection;

[0051] - [Fig. 11] illustrates the placement of a peripheral strip on the fusible joint bed;

[0052] - [Fig. 12] illustrates the result of installing a second interconnecting plate;

[0053] - [Fig. 13] illustrates the completed sealing and insulation assembly;

[0054] - [Fig. 14], [Fig. 15] and [Fig. 16] illustrate variants of the fusible joint bed.

[0055] Similar and common elements in the various embodiments bear the same reference numbers to the figures. DETAILED DESCRIPTION

[0056] 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).

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] This electrical insulating support 1 comprises a sheet of insulating material with a through-joint opening 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.

[0062] 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.

[0063] The electrical insulating support 1 can also, alternatively, have any other shape to correspond to stacks of different shapes (rectangular, circular, oval, etc.).

[0064] 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, by forming a passage for these transverse channels.

[0065] The through-jointing openings 2 of the insulating support 1 are, in this example, made in the form of discontinuous grooves extending along the jointing lines. These jointing lines are arranged around the central window 3 and around the side windows 4, according to the example illustrated in [Fig. 1].

[0066] 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-joint openings 2.

[0067] The electrical insulating support 1 is made from an assembly of peripheral strips 26 at the level of junction zones 27, according to a process described later.

[0068] Figure 2 is a partial cross-sectional view illustrating an elementary motif of the electrochemical reactor stacking, with an electrochemical cell 5 arranged between two interconnecting plates 6. An alternating stacking arrangement as defined by the present invention thus comprises, in a known manner, an alternation of electrochemical cells chemical 5 and interconnecting plates 6, as many times as necessary depending on the desired stacking size, superimposed along a stacking direction D.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.).

[0073] 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.

[0074] 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.

[0075] The electrochemical reactor further comprises a sealing assembly and insulation 12 allowing to create a seal between the interconnecting plates 6.

[0076] This sealing and insulation assembly 12 is formed of the electrical insulating support 1 of [Fig.1], associated with a sealing gasket 13 which extends into the through jointing openings 2 of the electrical insulating support 1 by connecting two interconnecting plates 6 through the through jointing openings 2.

[0077] A high-performance seal is thus achieved from one interconnection plate 6 to the other, by a sealing joint 13 passing through each through jointing opening 2.

[0078] The arrangement of the through-joint openings 2, implemented here as joint lines along which discontinuous grooves extend, ensures the physical integrity of the electrical insulating support 1, 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.

[0079] Figure 3 illustrates a first step of the process, which consists of producing a plurality of peripheral strips 26 from a sheet of electrically insulating material, such as a mica sheet. In the present example, a mica sheet of approximately 0.8 millimeters can be used.

[0080] The peripheral strips 26 are produced from the sheet of electrically insulating material by mechanical cutting, laser cutting, machining, or any other suitable means.

[0081] Each of the peripheral strips 26 has two longitudinal ends provided with joining zones 27. The joining zones 27 are intended for edge-to-edge assembly of the different peripheral strips 26. The term "longitudinal ends" refers to the fact that the peripheral strips 26 thus produced necessarily extend along a longitudinal direction. In other words, the peripheral strips 26 have a so-called longitudinal dimension, which is greater than a so-called transverse dimension (which is perpendicular to the longitudinal dimension). These longitudinal ends are therefore the portions located in zones of the peripheral strip 27 that border the latter along the longitudinal direction.

[0082] In the illustrated example, the peripheral bands 26 have a rectangular outline. The longitudinal direction then corresponds to the length of the rectangle, and the transverse direction corresponds to the width of the rectangle. The longitudinal extremities correspond to areas close to the shorter sides of these rectangles, that is, to the shorter sides themselves, or to portions of the longer sides that are adjacent to the shorter sides.

[0083] In the example of [Fig. 3], the peripheral bands 26 have areas of junction 27 formed by straight edges (the short sides of the rectangle formed by the peripheral bands 26 in this example).

[0084] A lateral window 4 is then made in at least one of these peripheral bands 26. This lateral window 4 is adapted to form a passage for a transverse channel 7 mentioned previously. In the present example, a lateral window 4 is made in each of the peripheral bands 26.

[0085] Through jointing openings 2 are also made in the peripheral strips 26. These through jointing openings 2 are made along the chosen jointing lines (Fig. 3 gives an example of double jointing lines arranged around the side window 4.

[0086] These through-jointing openings 2 are made separately or simultaneously with the side window(s) 4, and / or with the cutting of the peripheral strips 26, by the same means (for example mechanical cutting, laser cutting, machining, or any other suitable means).

[0087] Figures 1 and 6 to 8 further illustrate other variants of junction zones 27 and arrangement of through jointing openings 2. [Fig. 1] illustrates a variant of the peripheral bands 26, in which they have a trapezoidal shape, with junction zones 27 formed by straight edges arranged at 45 degrees to the longitudinal axis of the peripheral band 26. Figures 6 to 8 illustrate other variants described later.

[0088] The peripheral bands 26 are thus generally rectangular or trapezoidal in shape, with junction zones 27 adjacent to at least two corners of said shapes. Indeed, for example, in the case of a rectangle, the junction zone 27 may be: - the short side of the rectangle, and is thus adjacent to a corner of the rectangle; - a portion of the longer side of the rectangle, which is adjacent to a corner of the rectangle.

[0089] Following the production of the peripheral strips 26, the process continues with a step illustrated in [Fig. 4]. In this step, an electrically insulating support 1 is formed on a first interconnecting plate 6 by assembling the four peripheral strips 26 of [Fig. 3]. [Fig. 4] is a perspective view showing three of the peripheral strips 26 already in place on the first interconnecting plate 6 and a fourth peripheral strip 26 being placed.

[0090] The electrical insulating support 1 is thus formed by the assembly of several peripheral strips 26 at their junction areas 27. In the present example, four peripheral strips 26 are assembled to form an electrical insulating support 1. The assembly of the peripheral strips 26 forms a frame delimiting the central window 3, according to dimensions designed to receive an electrochemical cell 5.

[0091] Figure 4 illustrates an example in which the assembly of the peripheral strips 26 The connection at their junction zones 27 is achieved indirectly by means of joining pieces 28. These joining pieces 28 are preferably of the same thickness as the peripheral strips 26, and can also be produced from a sheet of electrically insulating material. Preferably, the peripheral strips 26 and these joining pieces 28 are cut in the same way from the same sheet of electrically insulating material.

[0092] In this particularly advantageous example, the peripheral strips 26 are rectangles, and the connecting pieces 28 are triangles formed by cutting a square or rectangle along a diagonal. The cuts made in a sheet of electrically insulating material are thus produced with very little material loss, resulting in a considerable reduction in the cost price of the electrochemical reactor, given the price and the numerous thicknesses of sheet insulating material required to construct an electrical reactor.

[0093] Fig. 5 is a top view illustrating the assembly of Fig. 4 once completed. The four peripheral strips 26, with their longitudinal edges, form a central square window 3. The connecting pieces 28 are arranged edge to edge with the peripheral strips 26. The four connecting pieces 28 are arranged against the edges of the peripheral strips, at the level of their junction areas 27, so that the four peripheral strips 26 and the four connecting pieces 28 extend in the same plane, resting on the first interconnecting plate 6.

[0094] Figures 6 to 8 illustrate other shape variants for the peripheral bands 26 and their joining zones 27. In these figures, the through-jointing openings 2 have not been shown for clarity.

[0095] Figure 6 illustrates peripheral bands 26 of rectangular shape, as on the [Fig.3], but whose junction zones 27 are constituted by: - the edges formed by the short sides of the rectangles, for two of the peripheral bands 26 (the two peripheral bands which are vertical on the [Fig.6]); - portions of the edge of the long sides of the rectangles, adjacent to the short sides, for the two other peripheral bands 26 (the two peripheral bands which are horizontal on the [Fig.6].

[0096] Thus, in this example, the junction zones 27 allow the peripheral strips 26 to be assembled directly, without a junction piece, to form an electrically insulating support 1.

[0097] Figures 7 and 8 illustrate another variant of peripheral bands 26 in general trapezoidal shape, with oblique junction zones 27, as in the example of [Fig.1].

[0098] In addition, in this variant, connecting pieces 28 are also provided, and are here attached to the joining zones 27. The joining zones also have cutouts 31 with the complementary contour of the joining pieces 28, so that the joining pieces 28 fit into the cutouts 31 when the peripheral strips 26 are assembled by their joining zones 27. An interlocking of the peripheral strips 26 is thus obtained (in [Fig.7], the peripheral strips 26 are seen before their assembly and in [Fig.8], the peripheral strips 26 are assembled).

[0099] Alternatively, the joining pieces 28 can be add-on pieces, which each fit into two corresponding cutouts (one cutout on each joining area 27), when assembling two peripheral strips 26 by their joining areas 27.

[0100] The junction zones 27 may also have additional functional shapes. In the example illustrated in [Fig.7], the junction zones 27 have circular and oval notches forming holes (for example, positioning holes) in corners of the electrical insulating support 1.

[0101] Figure 8 illustrates the electrical insulating support 1 positioned on the first interconnecting plate 6. Figure 8 further illustrates a variant, applicable to all embodiments, in which the peripheral strips 26 are assembled around a template 30 (hatched in Figure 8) whose shape corresponds to the central window. The template 30 can, for example, be a rigid polymer sheet with a thickness similar to that of the peripheral strips 26.

[0102] The assembly of the peripheral strips 26 on the interconnection plate 6 is accompanied by the placement of a fusible joint deposit 29. This placement can be done before, simultaneously, or after the placement of peripheral strips 26 on the first interconnection plate 6.

[0103] The volume of fusible joint cords 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 jointing opening 2.

[0104] With reference to [Fig.9], fusible joint cords 29 are for example deposited in the through-joint openings 2, or around these through-joint openings 2. [Fig.9] is a schematic perspective view showing the fusible joint cords 29, with shapes corresponding to the through-joint openings 2, ready to be deposited on a peripheral strip 26, before or after its placement on the first interconnection plate 6.

[0105] The fusible seal 29 is, 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 beads of paste may be used, for example spraying, additive manufacturing, cast and pre-cut strip seals, etc.

[0106] In the present example, the fusible joint 29 can be deposited in the form of beads having a width of approximately 1 to 2 mm.

[0107] The material constituting the deposited fusible seal 29 is a material having a melting point beyond which it will form a seal that is leak-proof against reaction fluids and electrically insulating, this melting point being higher than the operating temperature of the electrochemical reactor. Preferably, this material is glass-based or glass-ceramic. It can also be based on other materials, such as a suitable ceramic or polymer.

[0108] In this example, the fusible seal 29 consists of a mixture of glass powder, an ethanol-type solvent, and a terpineol-type binder. Additional components may be provided, such as components acting as dispersants and plasticizers, improving the casting of the fusible seal 29.

[0109] This joint 29 is fusible, because when the melting point of the glass powder is reached, the glass powder agglomerates into molten glass, to form the joint extending into the through-jointing openings 2 of the electrical insulating support 1. The glass powder in this example is ground glass, with an average particle size between 30 pm and 0.1 pm.

[0110] The next step of the process consists of carrying out an alternating stacking of electrochemical cell 5 and interconnecting plate 6, comprising at least: - said first interconnection plate 6; - the electrical insulating support 1 which was formed by assembling the peripheral strips 26 on this first interconnection plate 6; - an electrochemical cell 5 arranged on the first interconnection plate 6, in the central window 3; - the fusible joint 29; and - a second interconnection plate 6.

[0111] In practice, a solid oxide electrochemical reactor comprises a large number of stages, each consisting of a pair of interconnecting plates 6, between which is arranged an electrochemical cell 5, with sealing ensured by a sealing and insulation assembly 12 which includes an electrical insulating support 1 made as described previously, by the assembly of the peripheral strips 26.

[0112] The alternating stack of electrochemical cell 5 and interconnecting plate 6 therefore comprises at least the elements listed above, which constitute one stage of the stack, and generally comprises several of these stages.

[0113] Preferably, the alternating stacking of electrochemical cell 5 and interconnecting plate 6 is achieved by assembling as many elementary motifs as there are desired stages for the electrochemical reactor. Each elementary motif consists of an interconnecting plate 6 on which peripheral strips 26 were assembled into an electrically insulating support 1, with the installation of an electrochemical cell 5, as explained previously. Several of these elementary motifs are then stacked, the interconnecting plate of the top motif forming the second interconnecting plate of the motif below. A final interconnecting plate 6 then caps this stack.

[0114] The next step of the process consists of pressing this alternating stack along the stacking direction, and bringing the alternating stack to a melting temperature of the fusible joint 29, so that this fusible joint 29 extends into the through jointing openings 2 of the electrical insulating support 1, formed by the assembly of the peripheral strips 26, and thus forms a sealing joint 13 connecting two interconnecting plates 6 through the through jointing openings 2 of the electrical insulating supports 1.

[0115] The assembly of an alternating stack of electrochemical cells 5 and interconnecting plates 6 is preferably carried out in a press having guiding means along the stacking direction. The preliminary step of assembling the peripheral strips onto the first interconnecting plate is also preferably carried out directly in this same press.

[0116] Another embodiment of the process, which is particularly advantageous, will now be described. According to this embodiment, the peripheral strips 26 are not assembled directly in contact with the first interconnecting plate 6, but are assembled on this plate via a bed of fusible joint 29.

[0117] The peripheral strips 26 are first produced according to one of the variants described above, with their side window 4, their through jointing openings 2, and their junction zones 27.

[0118] Fig. 10 illustrates a subsequent step of the process in which a bed of fusible joint 29 is deposited on the first interconnecting plate 6.

[0119] The fusible joint bed 29 can be formed by depositing extruded paste. The entire fusible joint bed 29 can thus be produced by extrusion and then applied to the interconnecting plate 6. According to another embodiment, the fusible joint bed 29 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 29 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 29 illustrates this formation of adjacent joint beads.The fusible joint bed 29 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 method adapted to depositing a bed of... fusible joint can be used, for example by spraying, strip casting, additive manufacturing, etc.

[0120] Fig. 11 schematically illustrates the next step of the process, in which the various peripheral strips 26 are deposited on this first bed of fusible joint 29. This operation is the same as that illustrated in Figures 4 and 5, except that the peripheral strips 26 are deposited on the first bed of fusible joint 29, the latter resting on the first interconnection plate 6.

[0121] The [Fig. 11] is a partial view showing only a portion of a peripheral strip 26, provided with its through jointing openings 2, placed on the first bed of fusible joint 29.

[0122] Once the assembly of the peripheral strips 26 is completed on this bed of fusible joint 29, the electrical insulating support 1 thus formed then rests on this first bed of fusible joint 29. At this stage, it is optionally possible to fill the through jointing openings 2 with cords of fusible joint 29.

[0123] The next step of the process consists of placing a second interconnecting plate 6 on the previous assembly. This second interconnecting plate 6 has a second bed of fusible seal 29 that has been previously deposited on it. The second interconnecting plate 6 is positioned on the first interconnecting plate 6 so that this second bed of fusible seal 29 comes into contact with the peripheral strips 26.

[0124] In the example illustrated in [Fig. 12], the through jointing openings 2 are also fitted with fusible seal 29.

[0125] The next step of the process is the realization of the alternating stacking of interconnecting plates 6 and electrochemical cell 5. Figures 12 and 13 are schematic and represent only one stage.

[0126] The alternating stacking can be achieved starting from the assembly of [Fig. 12], which illustrates a first stage, by building up the stages one on top of the other. The alternating stacking is achieved by reproducing an elementary pattern, by depositing a bed of fusible joint 29 on the upper face of the second interconnecting plate 6, that is to say the face which is opposite the first interconnecting plate 6. More precisely, starting from the first stage of [Fig.

[12] , a new bed of fusible joint 29 is thus deposited on the upper face of the second interconnection plate 6, then a new electrical insulating support 1 is formed on this new bed of fusible joint 29, by assembling new peripheral strips 26, with the installation of a new electrochemical cell 5 in this second stage, and the installation of a third interconnection plate 6 which has a bed of fusible joint 29 on its lower face. The second stage thus formed, a third stage can be made in the same way, and so on.

[0127] The next step of the process is as described above, and consists of pressing this alternating stacking along the stacking direction, and to bring the alternating stacking to a melting temperature of the fusible joint 29, so that this fusible joint 29 extends into the through jointing openings 2 of the electrical insulating support 1, formed by the assembly of the peripheral strips 26, and thus forms a sealing joint 13 connecting two interconnecting plates 6 through the through jointing openings 2 of the electrical insulating supports 1.

[0128] During this step, the distribution of the fusible seal 29 allows the sealing gasket 13 to be put in place with little movement of the fusible seal 29, which is favorable to the formation of the electrical insulating support 1 by the assembly of the peripheral strips 26.

[0129] Fig. 13 illustrates the result of this pressing and heating with the sealing gasket 13 which connects two interconnecting plates 6 through the through-jointing openings 2. The fusible gasket takes its shape and solidifies into a solid sealing gasket 13 which will also fix the shape of the electrical insulating support 1, and thus fix the assembly of the peripheral strips 26.

[0130] In addition, any gaps between the junction zones 27, and / or between the junction zones 27 and any connecting parts 28, will also be filled by the fusible seal and fixed by the sealing gasket 13, ensuring sealing at the junction zones 27, in the same way as at the through jointing openings 2.

[0131] The fusible joint bed 29 deposited on the first and / or second interconnecting plate 6 can take on different configurations as long as it allows for the support and assembly of the peripheral strips 26. Figures 14 and 15 illustrate variations in the deposition of the fusible joint beds 29. These fusible joint beds 29 can be produced as discontinuous fusible joint beads 29, using parallel and spaced joint beads. [Fig. 14] illustrates such fusible joint beads 29 formed by the deposition of a cylindrical bead. [Fig. 15] illustrates such fusible joint beads 29 with a flattened profile.

[0132] Whatever the variant of the fusible joint bed 29, the latter may advantageously have adhesive properties, so that the assembly of the peripheral strips 26 is facilitated by their retention in place on the fusible joint bed 29 and therefore on the interconnecting plate 6. In this example, the fusible joint 29 may include in its formulation, in addition to the glass powder, an adhesive compound.

[0133] Figure 16 is an example illustrating a simplified alternating stacking of an electrochemical cell 5 and two interconnecting plates 6 with the fusible joint bed variant 29 of Figure 15. The peripheral strips 26 are arranged between the fusible joint beds 29, which are adapted to fill the through-joint openings 2 during the fusible joint 29 melting step.

[0134] Variants can be envisaged. For example, it is possible to provide any other shape for the peripheral strips 26 and their junction zones 27, as long as these shapes allow the constitution of an electrical insulating support 1 by the assembly of these peripheral strips 27 by their junction zones 27.

[0135] Alternatively, the result illustrated in Figures 12 and 16 can be obtained not by depositing a bed of fusible joint 29 on the interconnecting plates 6, but by depositing the bed of fusible joint 29 on each peripheral strip 26 (optionally on both faces of each peripheral strip 26), and then assembling them on the interconnecting plate 6, each peripheral strip 26 then being linked to its own bed of fusible joint 29.

[0136] Similarly, Figures 12 and 16 illustrate two beds of fusible seals 29 on the two faces of the electrical insulating support 1. However, alternatively, a single bed of fusible seals 29 is conceivable, the fusible seal 29 being distributed in the through openings of the jointing 2 by connecting the two interconnecting plates 6, during the pressing and heating step.

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, 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), these sealing and insulation assemblies (12) each comprising an electrically insulating support (1) pierced with through-sealing openings (2) and sealing gaskets (13) connecting two interconnection plates (6) through these through-sealing openings (2); this method being characterized in that it comprises the following steps: - producing a plurality of peripheral strips (26) from a sheet of electrically insulating material, these peripheral strips (26) each comprising two longitudinal ends provided with junction zones (27); - making a side window (4) in at least one of the peripheral strips (26), this side window (4) being adapted to form a passage for said transverse channel (7); - make through-joint openings (2) in each peripheral strip (26); - forming one of said electrical insulating supports (1) by assembling on a first interconnection plate (6) several of said peripheral strips (26) at their junction zones (27), forming a frame which delimits a central window (3) adapted to receive one of said electrochemical cells (5); - producing an alternating stack of electrochemical cells (5) and interconnection plates (6), comprising at least: said first interconnection plate (6) with the corresponding electrically insulating support (1), formed from said assembly of peripheral strips (26); one of said electrochemical cells (5) arranged in the central window (3) of the electrically insulating support (1); an electrically insulating fusible joint (29) in contact with the electrically insulating support (1); and a second interconnection plate (6); - pressing said alternating stack in the stacking direction, and bringing it to a melting temperature of the fusible joint (29), so that the fusible joint (29) extends into the through-sealing openings (2) of the electrically insulating support (1), and forms a seal (13) connecting two interconnection plates (6) through these through-sealing openings (2).

2. Method according to claim 1, characterized in that the peripheral strips (26) are of generally rectangular or trapezoidal shape, with junction zones (28) adjacent to at least two corners of said shapes.

3. Method according to one of the preceding claims, characterized in that it comprises a prior step of depositing a first electrically insulating fusible joint bed (29) on the first interconnection plate (6), and in that the assembly of several of said peripheral strips (26) is carried out on said first joint bed (29).

4. A method according to claim 3, characterized in that the first bed of fusible joint (29) is deposited in the form of a continuous strip of fusible joint.

5. A method according to claim 3, characterized in that the first bed of fusible joint (29) is deposited in the form of discontinuous beads of fusible joint.

6. Method according to one of claims 3 to 5, characterized in that the step of producing an alternating stack of electrochemical cells (5) and interconnection plates (6) is carried out by reproducing an elementary pattern, by depositing a bed of electrically insulating fusible joint (29) on the face of the second interconnection plate (6) which is opposite the first interconnection plate (6).

7. Procedure according to one of the preceding claims, characterized in that it comprises a prior step of depositing an electrically insulating fusible joint bed (29) on the second interconnection plate (6), and in that, during the step of producing an alternating stack of electrochemical cells (5) and interconnection plates (6), the second interconnection plate (6) is arranged on the first interconnection plate (6) so that this fusible joint bed (29) comes into contact with the peripheral strips (26).

8. Method according to one of the preceding claims, characterized in that, after the step of forming one of said electrically insulating supports (1), the through-sealing openings (2) of the peripheral strips (26) are provided with electrically insulating fusible joint (29).

9. Method according to one of the preceding claims, characterized in that, during the step of forming one of said electrically insulating supports (1), the peripheral strips (26) are assembled by joining pieces (28) complementary to the joining zones (27).

10. Method according to claim 9, characterized in that the joining pieces (28) fit into the joining zones (27).

11. Method according to one of claims 9 or 10, characterized in that the joining pieces (28) are also produced during the step of producing a plurality of peripheral strips (26), from the same sheet of electrically insulating material.

12. Method according to claim 9, characterized in that the junction zones (27) comprise complementary shapes which fit together.

13. Method according to one of the preceding claims, characterized in that the step of forming one of said electrically insulating supports (1) is carried out by assembling the peripheral strips (26) around a template (30) with the dimension of the central window (3), this template (30) being arranged on the first interconnection plate (6).

14. Method according to one of the preceding claims, characterized in that, in the step of producing a plurality of peripheral strips (26), four identical peripheral strips (26) are produced from a sheet of insulating material.

15. Method according to one of the preceding claims, characterized in that, in the step of forming one of said electrically insulating supports (1), the through-jointing openings (2) are arranged in discontinuous grooves arranged along jointing lines.

16. Method according to claim 15, characterized in that the joining lines are arranged around the side window (4).

17. Method according to one of claims 15 or 16, characterized in that the joining lines are arranged around the central window (3).

18. Method according to one of the preceding claims, characterized in that, during the step of producing an alternating stack of electrochemical cells (5) and interconnection plates (6), the stack is produced in a press, and in that the step of forming one of said electrically insulating supports (1) by assembly on a first interconnection plate (6) of several of said peripheral strips (26) is produced in this same press.

19. Method according to one of the preceding claims, characterized in that the fusible joint (29) comprises: a glass, or vitro-ceramic, or ceramic powder; a solvent; and a binder.

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