Interconnector partition plate with folded edge and associated stack

Abstract

The invention relates to an interconnector partition plate (1) comprising an upper face and a lower face, parallel to each other and extending along a main plane, characterized in that it comprises a central part extending along the main plane and an edge integrally surrounding the central part, the edge being folded to form a non-zero angle A with the main plane. The invention also relates to the interconnector (100) for an electrolyser comprising the partition plate, an upper plate (101) in contact with the upper face (2) of the partition plate (1) and a lower plate (102) in contact with the lower face (3) of the partition plate (1). The invention also relates to a stack (300) comprising at least two interconnectors (100) and at least one elementary electrochemical cell (200) positioned between the interconnectors (100) and an electrolyser comprising the stack, an upper end plate (312) and a lower end plate (311).

Description

[0001] "Folded Edge Interconnector Separator Plate and Associated Stack"

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the optimization of interconnectors of electrochemical cells. The invention will find applications for the stacking of solid oxide cells called SOC for Solid Oxide Cell in English and in particular at the level of the interconnectors. This type of stack is used in systems for producing electricity from hydrogen and oxygen (solid oxide cell or fuel cell called SOFC for Solid Oxide Fuel Cell) or hydrogen and oxygen from water vapor (solid oxide electrolyzer cell called SOEC for Solid Oxide Electrolysiser Cells or high temperature electrolyzer EHT, or EVHT for high temperature water vapor electrolysis, or HTE for High Temperature Electrolysis, or HTSE for High Temperature Steam Electrolysis).

[0004] STATE OF THE ART

[0005] An SOC electrochemical cell is schematically represented by 3 layers, i.e. 2 electrodes separated by an electrolyte. The electrodes are the site of electrochemical reactions, and are electronically conductive, or even mixed electronic / ionic, while the electrolyte is only ionically conductive.

[0006] SOFC fuel cells are electrochemical cells producing electrical and thermal energy that use chemical energy generated by the reaction of water formation from hydrogen and oxygen.

[0007] The operating principle of a SOFC cell is based on the following mechanism: oxygen from the air, which is supplied to the cathode, is dissociated to give O2- anions. The anions thus formed migrate through the electrolyte until they reach the anode where they oxidize the hydrogen atoms which are supplied by the fuel. This reaction releases electrons and water.

[0008] An electrochemical cell operating as a SOEC (Solid Oxide Electrolysiser Cells), or EHT (High Temperature Electrolyzer), is a hydrogen-producing electrochemical cell whose operating principle is strictly the opposite of that of SOFCs. Indeed, in the case of a SOEC cell, water vapor is supplied to the cathode and the water molecules are dissociated into hydrogen and O2 anions. The anions thus formed diffuse through the electrolyte to recombine in the form of oxygen at the anode while the hydrogen remains, with the water vapor, at the cathode. This hydrogen can then be recovered to be used as fuel in other applications.

[0009] Generally speaking, an electrolyser or stack is made up of a stack of elementary modules placed in series from an electrical point of view.

[0010] An elementary module consists of an electrochemical cell composed of at least one electrolyte with two electrodes sandwiched between two interconnection plates, also called "interconnectors". A complete electrolyser is then an alternating stack of cells and interconnectors.

[0011] The cell, or electrolyte-electrode assembly, is a ceramic multi-layer assembly comprising at least a central ion-conducting layer which is a dense and waterproof solid electrolyte, sandwiched between two layers which constitute porous electrodes (additional layers may exist, but only serve to improve one of the already existing layers).

[0012] Interconnectors are electronic conductors that provide contact through one of their faces with the cathode of one cell and through the other face with the anode of the next cell.

[0013] The primary role of interconnectors, usually made of metal plates, is to supply the cell with electrical current. In addition, they also serve to distribute and recover gases while separating the anode and cathode compartments of two adjacent cells.

[0014] In current stack structures, this dual function of gas distribution and current supply to the cells is provided either by structures, for example in LSM (acronym for strontium-doped lanthanum manganite, a conductive ceramic component) machined to form networks of hydraulic channels, or by metal grids.

[0015] To ensure good electrical contact of the stack, the assembly is mounted between two rigid plates, called end plates, electrically insulated from the interconnectors. The sandwich thus formed, stack, must be maintained under a compressive force to ensure good electrical continuity of the contact planes between the interconnectors and the cells.

[0016] Interconnector plates are at the heart of EHT design. In the classic design implemented, these consist of a set of three thin plates in which openings are machined by laser cutting to ensure the passage of gases.

[0017] The design of the interconnector plates at the ends of the assembly is commonly different with plates having modified openings, having different feed openings depending on the type (lower or upper).

[0018] Interconnectors are often made of thin welded plates, which offers an economic advantage. The manufacturing method, which involves laser cutting and welding thin sheets, is much less expensive in terms of manufacturing costs than machining (or additive manufacturing) structures with complex geometries to form flat structures to power the cells within the stack. The use of metal strips a few tenths of a millimeter thick also limits the amount of material used, an important parameter when the number of stack stages increases significantly. This technical solution makes it possible to mass-produce components and to have large exchange surfaces in a very compact assembly to power the electrochemical cells.The thinness of the plates nevertheless imposes significant manufacturing constraints requiring very good control of the manufacturing processes to guarantee the geometry (flatness / straightness) of the components, necessary for the assembly of stacks composed of several dozen interconnectors. There is therefore a need to optimize the interconnectors to offer a solution that is both economical, easy to implement and ensures optimal operation of the electrolysers.

[0019] SUMMARY OF THE INVENTION

[0020] To achieve this objective, according to one aspect, an interconnector separation plate is provided, advantageously electrical and fluidic, for a solid oxide electrolyzer, advantageously high temperature, comprising an upper face and a lower face, parallel to each other and extending along a main plane, characterized in that it comprises a central part extending along the main plane and an edge completely surrounding the central part, the edge being folded to form a non-zero angle A with the main plane.

[0021] The folded edge of the separator plate helps stiffen the interconnector and protect the side faces once stacked to form an electrolyzer. This allows the continued use of thin plates while ensuring greater rigidity and easier implementation of the stack. In addition, the presence of the folded edge allows the heat exchange capacity of the interconnectors in the stack to be adjusted.

[0022] According to another aspect, the invention relates to an interconnector for a solid oxide electrolyzer comprising a separation plate as described above, an upper plate in contact with the upper face of the separation plate and a lower plate in contact with the lower face of the separation plate. The interconnector according to the invention allows self-guiding and self-nesting of the interconnectors during packaging of the stack.

[0023] According to another aspect, the invention relates to a solid oxide stack comprising at least two interconnectors as described above and at least one elementary electrochemical cell, advantageously with solid oxides, comprising a cathode, an anode and an electrolyte intercalated between the cathode and the anode, the elementary electrochemical cell being intercalated between the interconnectors.

[0024] In another aspect, the invention relates to a solid oxide electrolyzer comprising a stack as described above and an upper end plate and a lower end plate.

[0025] According to another aspect, the invention relates to a method of manufacturing an interconnector as described above comprising a step of stacking the upper plate on the upper face of the separation plate and the lower plate on the lower plate of the separation plate then a step of welding the plates characterized in that it comprises a step of stamping by a stamping die of the separation plate to form the folded edge before stacking or after stacking and before the welding step.

[0026] BRIEF DESCRIPTION OF THE FIGURES

[0027] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0028] Figure 1 shows an exploded view of the components of a high-temperature electrolyzer stack.

[0029] Figure 2 shows an exploded view of an interconnector according to one aspect of the invention.

[0030] Figure 3 shows an interconnector according to Figure 2 assembled with through-weld areas.

[0031] Figure 4 shows a stamping die for forming the separation plate according to the invention.

[0032] Figure 5 shows a perspective view of an electrolyzer formed from a stack of five interconnectors

[0033] Figure 6 shows a side view of Figure 5.

[0034] Figure 7 shows a sectional view of two interconnector separation plates and the geometric configuration of the folded edges.

[0035] Figure 8 shows the variation of the clearance between two interconnector separation plates as a function of the angle A of the folded edge for thickness values ​​E ranging from 0.5 to 1 mm and distance D ranging from 0.5 to 2.5 mm.

[0036] Figure 9 shows a sectional view of an interconnector according to Figure 3.

[0037] Figure 10 shows a side view of an electrolyzer according to an embodiment comprising a cord and a shim arranged on the folded edge of the separation plate.

[0038] Figure 11 shows a side view of a stack of five interconnectors according to Figure 10.

[0039] Figure 12 shows a side sectional view of a stack of five interconnectors according to Figure 10.

[0040] Figure 13 represents a sectional view and its detail according to Figure 10 before packaging of the stack.

[0041] Figure 14 represents a sectional view and its detail according to Figure 10 after conditioning of the stack.

[0042] Figure 15 shows a sectional view of a stack of interconnectors comprising a cord and a filling with an insulating material arranged in the clearance formed between the folded edges of the superimposed interconnectors.

[0043] Figure 16 shows a sectional view of a stack of interconnectors including a cord and a repair sealant filling following a leak from a leaking interconnector arranged in the gap formed between the folded edges of the superimposed interconnectors.

[0044] Figure 17 shows a cross-sectional view of a stack of interconnectors comprising a cord and conductive materials so as to form an electrical shunt between the folded edges of the superimposed interconnectors.

[0045] Figure 18 shows an interconnector separation plate including a voltage measuring wire passage hole arranged in the folded edge.

[0046] Figure 19 shows a stack of interconnectors at least some of which include a separation plate according to Figure 18.

[0047] Figure 20 shows an electrolyzer comprising the stack according to Figure 19.

[0048] Figure 21 shows a top view of a circular interconnector including a cord.

[0049] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. In particular, the thicknesses of the different plates or layers are not representative of reality.

[0050] DETAILED DESCRIPTION OF THE INVENTION

[0051] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below:

[0052] For example, angle A is greater than 20° and less than 90°;

[0053] By way of example, the separation plate comprises in the central part 5 at least one opening 7, preferably four, advantageously in the form of a comb, to form inlet and outlet supply channels for the gases;

[0054] For example, the separating plate 1 is larger than the upper plate 101 and the lower plate 102 so that the folded edge 6 protrudes from the lower plate 102 and the upper plate 101;

[0055] For example, the separation plate 1 comprises in the folded edge 6 at least one passage hole 8 intended to receive a tension cable 311; For example, the stack 300 comprises a clearance X between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a separation plate 1 of a second interconnector 100, which is adjacent to the first interconnector 100, the clearance X being equal to E + E.cos (A) - d.cos (A), E being the thickness of the separation plate (1) and d being the distance between the lower face 3 of the central part 5 of the separation plate 1 of the first interconnector 100 and the upper face 2 of the central part

[0056] 5 of the separation plate 1 of the second interconnector 100;

[0057] For example, the folded edge of a first interconnector and the folded edge of a second interconnector are parallel;

[0058] By way of example, the stack comprises a gas-tight cord 100 arranged at least partially between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a separation plate 1 of a second interconnector 100;

[0059] By way of example, the stack comprises at least one shim 302 arranged at least partially between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a separation plate 1 of a second interconnector 100;

[0060] By way of example, the stack comprises an electrically and / or thermally insulating material arranged at least partially between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a separation plate 1 of a second interconnector 100;

[0061] For example, the stack comprises an electrically conductive material arranged at least partially between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge

[0062] 6 of a separation plate of a second interconnector 100;

[0063] By way of example, the stack comprises a repair glass slip arranged at least partially between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a separation plate 1 of a second interconnector 100;

[0064] For example, the method of manufacturing a separator plate includes a step of stamping the separator plate by a stamping die to form the folded edge;

[0065] For the remainder of the description, 'top' and 'bottom', or their derivatives, mean a quality of relative positioning of a cell unit element or stack as shown in the figures, the 'top' being oriented away from the ground and the 'bottom' 1 being oriented towards the ground. The upper end is at the top and the lower end is at the bottom.

[0066] Vertical means that which is directed according to the thickness of the stack or cell unit, that is to say according to the main direction of extension of the stack or cell unit, and horizontal means that which is perpendicular to the vertical. The top and the bottom are vertically opposed.

[0067] Transverse means a direction perpendicular to a longitudinal direction. The longitudinal direction means a direction perpendicular to the thickness of the stack or cell unit. A transverse section is a section perpendicular to the longitudinal axis. A transverse section is a section along the thickness of the stack or cell unit. A longitudinal section is a section perpendicular to the thickness of the stack or cell unit.

[0068] A parameter "substantially equal / greater / less than" or "of the order of" a given value means that this parameter is equal / greater / less than the given value, to within plus or minus 10%, or even plus or minus 5%, of this value.

[0069] For the purposes of this disclosure, the expression "A and / or B" means (A), (B) or (A and B). For the purposes of this disclosure, the expression "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0070] The terms "first," "second," and "third," "additional," etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0071] The term "upper" used in particular to describe a face of a layer is here only used to designate the first of the two faces of a layer (the other being the lower face), without making any assumptions about the relative position of the faces, in a vertical direction. The upper face could thus also have been called the front face, as opposed to a rear face.

[0072] The shapes or dimensions given for certain components of the present invention are always only indicative and are understood as including substantially equivalent shapes and dimensions.

[0073] It is specified that in the context of the present invention, the term "on", "overcomes", "covers", "above" or "underlying" or "below" or their equivalents do not necessarily mean "in contact with". For example, the deposition of a first layer on a second layer does not necessarily mean that the two layers are directly in contact with each other, but it does mean that the first layer at least partially covers the second layer either by being directly in contact with it, or by being separated from it by at least one other layer or at least one other element.

[0074] The word "dielectric" refers to a material whose electrical conductivity is low enough in the given application to serve as an insulator.

[0075] An element “based” on a material A means an element comprising this material A only or this material A and possibly other materials.

[0076] It should be noted that all the electrolysers or fuel cells described are of the solid oxide type (SOEC, acronym for "Solid Oxide Electrolyte Cell" or SOFC, "Solid Oxide Fuel Cell") operating at high temperature. Thus, all the components (anode / electrolyte / cathode) of an electrolysis cell are ceramics. The high operating temperature of an electrolyser (electrolysis reactor) is typically between 600°C and 1000°C.

[0077] In Figure 1 is illustrated an exploded view of certain components of a stack 300 of a high temperature electrolyzer.

[0078] Each electrochemical cell 200 is formed of a cathode 201 and an anode 203, placed on either side of a solid electrolyte 202 generally in the form of a membrane. The two electrodes 201 and 203 (cathode and anode) are electronic conductors, made of porous material, and the electrolyte is gas-tight, electronically insulating and ionically conductive. The electrolyte 202 may in particular be an anionic conductor, more precisely an anionic conductor of O2' ions and the electrolyzer is then called an anionic electrolyzer.

[0079] The electrolyte 202 interposed between the two electrodes 201, 203 is the place of migration of the 02 ions under the effect of the electric field created by the potential difference imposed between the anode 203 and the cathode 201.

[0080] As illustrated in Figure 1, the water vapor at the cathode inlet 201 can be accompanied by hydrogen H2 and the hydrogen produced and recovered at the outlet can be accompanied by water vapor. The injection of a draining gas can be added with the additional function of acting as a thermal regulator.

[0081] To increase the flow rates of hydrogen and oxygen produced, it is known to stack several elementary electrochemical cells 200 on top of each other, separating them by interconnection devices, usually called interconnectors 100 or bipolar interconnection plates. The assembly is positioned between two end interconnection plates 312, 313 which support the electrical supplies and gas supplies of the electrolyzer (electrolysis reactor).

[0082] The interconnectors 100 have a role of fluidic and electrical connection, they are in electrical contact with one or more electrodes 201, 203 generally ensure the functions of supplying and collecting electric current and delimit one or more gas circulation compartments.

[0083] Thus, a so-called cathode compartment has the function of distributing the electric current and water vapor as well as recovering the hydrogen at the cathode 200 in contact.

[0084] A so-called anode compartment has the function of distributing the electric current as well as recovering the oxygen produced at the anode 203 in contact, possibly using a draining gas.

[0085] The interconnector 100 comprises a separation plate 1 as well as an upper plate 101 and a lower plate 102.

[0086] According to one aspect, the invention relates to an interconnector separation plate 1. The separation plate 1 comprises an upper face 2 and a lower face 3. The upper face 2 and the lower face 3 are parallel to each other. The separation plate 1 extends along a main plane 4.

[0087] The separation plate 1 comprises a central part 5 and an edge 6 completely surrounding the central part 5. The edge 6 is folded so as to form a non-zero angle A with the main plane 4.

[0088] The interest of this modification of the geometry of the separation plate which can be called a middle plate is multiple. Among the potential advantages offered by this geometry compared to the flat geometry, it is noted that the separation plate with folded edge 6 contributes to stiffening the interconnector 100 and to protecting the external faces of the stack.

[0089] By stiffening the edge of the interconnectors 100, the risk of electrical contact between the superimposed interconnectors 100 is limited and the handling of the plates is facilitated. The folded edges 6 not only limit the overflow of the glass-ceramic, but also by preventing access to the insulating plates, they avoid the risks of breakage and disintegration of the plates that can be observed on the stacks in Figure 5. During the different phases of the stack's life, numerous handling operations of the stack are necessary between the assembly / manufacturing workshop, the packaging benches, the test benches and the assembly on the modules, to which are added transport and packaging. All these operations require the implementation of special precautions to protect the stack. The folded edges 6 contribute to the protection of the external structure of the stack against external aggressions.

[0090] The angle A is preferably less than 90°. Preferably, the angle A is between 20° and 70°, for example of the order of 60° to 65°.

[0091] The folded edge 6 is preferably flat. According to one possibility, the separation plate comprises an elbow 9 forming the junction between the central part 5 extending along the main plane 4 and the folded edge 6.

[0092] The folded edge 6 has an inner surface and an outer surface. The inner surface is understood as the surface of the folded edge 6 on the side of the angle A while the outer surface is understood as the surface of the folded edge 6 opposite. As an example in the figures, the inner surface corresponds to the upper face 2 of the separation plate and the outer surface corresponds to the lower face 3 of the separation plate 1.

[0093] According to one embodiment, the separation plate 1 comprises openings 7 to ensure the fluid circulation of the gases with the anode 203 and the cathode 201.

[0094] According to an illustrated, but non-limiting, possibility, the separation plate 1 comprises four openings 7 arranged face to face, preferably two by two at the periphery of the central part. The openings 7 are for example of elongated shape and are parallel two by two. The openings 7 can take a comb shape to form supply channels advantageously intended to be in communication with the electrodes 201, 203 of the elementary electrochemical cells 200.

[0095] The separating plate 1 is, for example, made of stainless steel such as, for example, 1.4509 steels (ferritic stainless steel grade enriched with niobium and titanium) or 1.4760 and has, for example, a thickness E of the order of 0.2 to 1 mm, for example of the order of 0.5 mm.

[0096] According to one aspect, the invention relates to an interconnector 100 comprising a separation plate 1 as described above and an upper plate 101 and a lower plate 102. The lower plate 102 is in contact with the lower face 3 of the separation plate 1 and the upper plate 101 is in contact with the upper face 2 of the separation plate 1.

[0097] Preferably, the separation plate 1 has dimensions greater than those of the upper plate 101 and the lower plate 102. The dimensions of the separation plate 1 along the main plane 4 are greater than those of the upper plate 101 and the lower plate 102.

[0098] Advantageously, the folded edge 6 of the separation plate 1 of the interconnector 100 protrudes from the lower plate 102 and the upper plate 101.

[0099] According to one embodiment, the lower plate 102, the separation plate 1 and the upper plate 101 are superimposed and are secured by the formation of through welds 106. Advantageously, the through welds 106 illustrated in Figure 3 make it possible to form a single-piece plate constituting 2 independent gas distribution networks which will supply the 2 faces of the electrochemical cell 200.

[0100] According to a preferred embodiment, notably illustrated in the figures, one of the lower plate 102 or upper plate 101 is called the oxygen plate or O2 sheet while the other lower plate 102 or upper plate 101 is called the hydrogen plate or H sheet. 2 .

[0101] The O2 plate is advantageously hollowed out in its center, presenting four wide lateral openings 103 (feed clarinet) and two small feed windows 104 placed at the edge of the central recess; the H2 plate without central recess has the same four openings 103 and also two small feed windows 104 with an opening rotated by 90° relative to the O2 plate.

[0102] According to one aspect, the invention relates to a method of manufacturing the interconnector separation plate 1 comprising a step of forming the folded edge 6 by stamping the separation plate 1 by a stamping die 400.

[0103] According to one aspect, the invention relates to a stack 300 comprising at least one elementary electrochemical cell 200 as described above and at least two interconnectors 100 between which the elementary electrochemical cell 200 is interposed. Preferably, it comprises several elementary electrochemical cells 200, each interposed between 2 interconnectors 100.

[0104] Advantageously, the angle A formed between the main plane 4 and the folded edge 6 is identical for each separation plate 1 of each interconnector 100 of the stack 300.

[0105] Advantageously, the folded edges 6 of the superimposed interconnectors 100 are parallel. Preferably, the folded edges 6 extend along a plane inclined relative to the main plane 4.

[0106] The distance between two directly superimposed folded edges 6 is defined as the clearance X. This clearance X is understood before the packaging of the stack.

[0107] The presence of a gap X between two directly superimposed folded edges 6 generates a volume V. The volume V is understood to be the volume, or space, between the lower face 3, or external surface, of a folded edge 6 and the upper face 2, or internal surface, of a folded edge 6.

[0108] Advantageously, the angle A formed between the main plane 4 of the central part 5 and the folded edge 6 makes it possible to modify the clearance X formed between the folded edges 6.

[0109] The presence of the folded edge 6 and thus of a clearance X between the folded edges 6 makes it possible to adjust the heat exchange capacity with the exterior of the stack 300 either by increasing it or by reducing it.

[0110] In terms of assembly, the assembly of the stack with separation plates 1 according to the invention is identical to what is carried out on a conventional stack with a flat plate without any impact on the structure of the object or on the manufacturing process.

[0111] It is defined that the clearance X is a function of the thickness E of the separation plate 1, of the angle A and of the distance D separating two successive separation plates 1.

[0112] The distance D separating the two superimposed separation plates 1 is measured between the upper face 2 of a first separation plate 1 preferably at its central part 5 and the lower face 3 of a second separation plate 1 preferably at its central part 5.

[0113] Advantageously, the game X is defined by the following formula:

[0114] X = E.cos(A) - D.cos(A ).

[0115] Figure 8 illustrates the clearance X as a function of the angle A with a distance D between 0.5 and 2.5 mm and a thickness E between 0.5 and 1 mm. The angle A varies between 0 and 80 degrees. We can see that the clearance X is thus between 0.5 and 2.5 mm.

[0116] The clearance X between the folded edges 6 of the two superimposed interconnectors 100 advantageously does not depend on the radius of curvature of the stamping elbow 9. This has the advantage of ensuring the manufacture of the separation plate 1 according to easily definable parameters. Indeed, the radius of curvature of a stamped sheet is a parameter that is difficult to control in manufacturing, but producing an angle with a fine tolerance is much simpler to obtain.

[0117] The definition of the clearance X between the folded edges 6 also makes it possible to limit the parasitic movements of the interconnectors 100, which lead to flatness defects during the packaging of the stack.

[0118] The presence of the clearance X between two folded edges 6 makes it possible to use this space and to functionalize it according to the needs for the stack 300.

[0119] According to one possibility, the separation plate 1 of the interconnector comprises a ceramic deposit on the edge of the plate. The ceramic deposit has a thickness of 50 to 100 μm. The ceramic deposit is peripheral and localized. It is carried out on the separation plate flat before stamping.

[0120] According to one embodiment, the stack 300 comprises a gas-tight bead 301. This bead 301 makes it possible to provide a new sealing barrier at the periphery of the electrochemical cell 200. For example, the bead is formed by a casting step. Preferably, the casting step is carried out at the end of the assembly step of the stack 300. For example, the bead 301 is made of glass. The installation of this bead 301 is very simple thanks to the folded edge 6 of the interconnector 100. The bead 301 does not impact the mechanics of the stack during its packaging. The bead 300 can be used to form a barrier either for the hydrogen chamber H 2 either for the O2 oxygen chamber or for both chambers.

[0121] The cord 301 is arranged between the lower face 3 of a folded edge 6 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a second interconnector 100. The cord 301 is arranged in the clearance X between two successive folded edges 6. The cord 301 is advantageously in contact with the upper face 2 of a folded edge 6 of the interconnector 100, preferably, the cord 301 is arranged in contact with the electrochemical cell 200. For example, as illustrated in the figures, the cord 301 is arranged in contact between the upper face 2 and the solid electrolyte 202. The cord 301 may be at least partially arranged in the elbow 9 so as to be as close as possible to the electrochemical cell 200.

[0122] According to an alternative or complementary embodiment, the stack 300 comprises at least one shim 302 arranged between two adjacent folded edges 6. Preferably, at least one shim 302 is arranged between each folded edge 6 of successive interconnectors 100. The shims 302 can be used to control the relative movements of the plates during the collapse of the stack and to maintain flatness during assembly pressure. Indeed, off-center compression or non-homogeneous fusion of the seal during packaging of the stack without well-adapted guidance can lead to significant flatness defects. By packaging the stack with interconnectors 100 with the folded edges 6 and shims 302 sized according to the desired collapse height, it is possible to guarantee a very low clearance X at the end of packaging, figures 13 and 14.Once the packaging of the stack 300 has been carried out, the shims 302 can be left in place, if they are insulating, or removed.

[0123] The shim 302 is advantageously arranged between the lower face 3 of a folded edge 6 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a second interconnector 100. The shim 302 is arranged in the clearance X between two successive folded edges 6. The shim 302 is advantageously in contact with the upper face 2 of a folded edge 6 of the interconnector 100. According to one possibility, the shim 302 is in contact with the lower face 3 of the folded edge 6 of the upper interconnector 100, more preferably after the step of compressing the stack 300.

[0124] Advantageously, the thickness of the shim 302 is adapted to ensure docking of the separation plates 1 of the interconnectors 100 after compression of the stack 300.

[0125] Advantageously, the 302 shim is made from glass slip cast in strip form.

[0126] According to one possibility, the shims 302 are arranged on the folded edge 6 in a discontinuous manner, that is to say that they do not form a continuity all along the folded edge 6.

[0127] According to an alternative or complementary embodiment of the previous one, the configuration according to the invention of a separation plate 1 with a folded edge 6 makes it possible to adjust the heat exchange capacity of the stack. This is particularly advantageous in that it is sought to be able to control a stack operating at high temperature by maintaining it in a so-called thermoneutral situation, where the quantity of heat necessary for the water electrolysis reaction is entirely provided by the electrical inputs.

[0128] The configuration according to this embodiment allows the choice of promoting or reducing the capacity of the stack 300 to exchange with its environment. It thus offers a possibility of adaptation with regard to the desired operating strategies and can therefore prove decisive in optimizing the lifespan of the electrolysers.

[0129] The geometry of the folded edge 6 contributes to very significantly increasing the convective and radiative exchange surface of the stack 300 compared to the planar configuration. In the planar interconnector configuration, the exchange surface is not only significantly smaller than with folded edges 6, but also the properties of the insulating materials (glass and mica) forming this surface contribute to increasing the thermal insulation of the stack.

[0130] According to one possibility, if the method of controlling the stack requires a stack thermally insulated from its environment, the shape of the interconnectors 100 according to the invention makes it possible to envisage the presence of an insulating material 303. The stack thus comprises a thermally and advantageously electrically insulating material 303 arranged between the lower face 3 of a folded edge 6 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a second interconnector 100. The thermally insulating material 303 is arranged in the clearance X between two successive folded edges 6. The insulating material 303 is advantageously in contact with the upper face 2 of a folded edge 6 of the interconnector 100, and preferably, arranged in contact with the lower face 3 of a folded edge 6 of a first interconnector 100. The insulating material 303 at least partially fills the volume V.For example, mineral powder (vermiculite, talc) or rock wool or glass wool foam / caulking can be used. In doing so, an insulating layer several millimeters thick can be formed, reducing the heat exchange between the core of the stack and its surroundings.

[0131] Advantageously, in the event of the appearance of a continuous gas jet type leak which could lead to the formation of a flame 305, the folded edge 6 acts as a deflector. The folded edges 6 of the interconnectors 100 placed above or below the defective interconnector 100 are not in direct view unlike the flat configuration.

[0132] In an alternative or complementary embodiment, the stack comprises at least one repair material 304 arranged between the folded edges 6 of two successive interconnectors. For example, a glass slip type repair seal for sealing a leak is arranged in the clearance X between the folded edges 6.

[0133] According to an alternative or complementary embodiment, the stack comprises at least one electrically conductive material arranged between the folded edges 6 of two successive interconnectors. For example, a metal shim 305 coated with ceramic glue 307 is arranged between two folded edges 6, preferably in contact with the latter so as to produce an electrical shunt or bypass 309. This arrangement makes it possible to repair the stack 300 in the event of failure of an electrochemical cell 200 or a leaking interconnector 306. This makes it possible to ensure the electrical continuity of the passage of the current 310 through the stack 300 thanks to an electrical shunt 309 of the defective interconnectors 100 by ensuring the passage of current 310 through the folded edge 6 of the interconnector 100.

[0134] According to an alternative or complementary embodiment, the folded edge 6 makes it possible to provide a space, or volume V, for arranging at least one tension cable 311. The pointing of the tension cables 311 is quite fragile and the fact of carrying it out on the upper face 2 which is the internal face of the folded edge 6 allows them to be protected from the risks of tearing and parasitic contact with adjacent interconnectors 100.

[0135] According to an alternative or complementary embodiment, the folded edge 6 comprises at least one passage hole 8. The passage hole 8 is through and advantageously allows the passage of tension wire 311 between the upper face 2 of the interconnector 100 and the lower face 3 of the interconnector 100.

[0136] According to one aspect, the invention relates to an electrolyser 500 comprising a stack 300 comprising at least one elementary electrochemical cell 200 as described above and at least two interconnectors 100 between which the elementary electrochemical cell 200 is interposed and an upper end plate 312 and a lower end plate 313 comprising fixing means so as to apply compression to the stack 300.

[0137] In all of Figures 1 to 20, the separation plate 1 and the interconnectors 100 are parallelepipedal in shape without being limiting. In Figure 21, a separation plate 1 and an interconnector 100 are shown as an example in a circular shape. The circular shape of the electrochemical cell stack figure 200 is parallelepipedal, in particular square.

[0138] According to one aspect, the invention relates to a method of manufacturing an interconnector separation plate 1 comprising a step of stamping a separation plate to form a folded edge 6.

[0139] According to one aspect, the invention relates to a method of manufacturing an interconnector comprising a step of stacking an upper plate 101, the separation plate 1 and a lower plate 102.

[0140] Preferably, the method comprises a step of welding the stack of the upper plate 101, the separation plate 1 and the lower plate 102, by performing through welding.

[0141] The stamping step can be performed before or after the stacking step and before or after the welding step.

[0142] According to one embodiment, the method comprises a ceramic deposition step, advantageously thin, for example with a thickness of 50 to 100 μm on the edge of the separation plate 1 intended to form the folded edge 6. Preferably, the ceramic deposition step is carried out before the stamping step, it is carried out on the flat separation plate 1. This deposition step is a localized peripheral deposition.

[0143] According to one aspect, the invention relates to a method for manufacturing a stack 300 comprising a step of assembling an elementary electrochemical cell 200 comprising a cathode 201, an anode 203 and an electrolyte 202 interposed between the cathode 201 and the anode 203 between two interconnectors 100.

[0144] Preferably, the method comprises repeating the assembly step to form a stack 300 comprising a plurality of electrochemical cells 200 each interposed between two interconnectors 100 according to the invention.

[0145] According to one possibility, the method comprises a step of functionalizing the clearance X formed between the lower face 3 of a folded edge 6 of a separation plate 1 of a first interconnector 100 and the upper face 2 of a folded edge 6 of a separation plate 1 of a second interconnector 100.

[0146] For example, the functionalization step comprises a step of casting a bead 301 and / or the placement of a shim 302 and / or filling with an electrically and / or thermally insulating material and / or filling with an electrically conductive material.

[0147] The installation of shim 302 in the form, for example, of a strip of glass glued to the folded edge 6 makes it possible to carry out a cold assembly in which all of the interconnectors 100 are fitted.

[0148] The presence of the shim 302 with or without the cord 301 and with or without the ceramic deposit ensures, by conicity effect, guidance of the interconnectors during the packaging of the stack 300.

[0149] During packaging, the fusion of the shims 302 positioned on the periphery of the stack at the level of the folded edges 6 of the interconnectors 100 makes it possible to accompany the collapse of the stack during packaging in a manner synchronized with that of the internal vitroceramic seals.

[0150] Preferably, the method comprises a step of positioning an upper end plate 312 and a lower end plate 313 at the ends of the stack 300 to form the electrolyser.

[0151] The method of manufacturing an electrolyser advantageously comprises a step of compressing the stack between the upper terminal plate 312 and the lower terminal plate 313.

[0152] LIST OF REFERENCES

[0153] 1. Separator plate

[0154] 2. Upper face

[0155] 3. Underside

[0156] 4. Main plan

[0157] 5. Central part

[0158] 6. Edge

[0159] A. angle

[0160] 7. Opening

[0161] 8. Passage hole

[0162] 9. Elbow

[0163] 100. Interconnector

[0164] 101. Top plate

[0165] 102. Bottom plate

[0166] 103. Side opening

[0167] 104. Power windows

[0168] 105. Hollowing

[0169] 106. Through weld

[0170] 200. Electrochemical cell

[0171] 201. Cathode

[0172] 202. Electrolyte

[0173] 203. Anode

[0174] 300. Stacking

[0175] 301. Cord

[0176] 302. Wedge

[0177] 303. Insulating material

[0178] 304. Repair seal

[0179] 305. Flame

[0180] 306. Leaking interconnector

[0181] 307. Conductive ceramic adhesive

[0182] 308. Metal wedge 309. Electrical shunt

[0183] 310. Current passage

[0184] 311. Voltage measuring cables

[0185] 312. Upper end plate 313. Lower end plate

[0186] 400. Stamping die

[0187] 500. Electrolyzer

[0188] X. Clearance between folded edges

[0189] E. Thickness of a separation plate

[0190] D. Distance between the lower face of the central part of the separation plate of the first interconnector and the upper face of the central part of the separation plate of the second interconnector

Claims

CLAIMS 1. Interconnector (100) for a solid oxide electrolyser comprising a separation plate (1) comprising an upper face (2) and a lower face (3), parallel to each other and extending along a main plane, the separation plate comprising a central portion (5) extending along the main plane and an edge completely surrounding the central portion (5), the edge being folded to form a non-zero angle A with the main plane, characterised in that the interconnector comprises an upper plate (101) in contact with the upper face (2) of the separation plate (1) and a lower plate (102) in contact with the lower face (3) of the separation plate (1).

2. Interconnector (100) according to the preceding claim wherein the separation plate (1) is of dimensions greater than those of the upper plate (101) and the lower plate (102) so that the folded edge (6) protrudes from the lower plate (102) and the upper plate (101).

3. Interconnector (100) according to any one of the preceding claims wherein the angle A is greater than 20° and less than 90°.

4. Interconnector (100) according to any one of the preceding claims wherein the separation plate (1) comprises in the central part (5) at least one comb-shaped opening (7) to form inlet and outlet gas supply channels.

5. Interconnector (100) according to any one of the preceding claims wherein the separation plate (1) comprises in the folded edge (6) at least one passage hole (8) intended to receive a tension cable (311).

6. Solid oxide stack (300) comprising at least two interconnectors (100) according to any one of the preceding claims and at least one elementary electrochemical cell (200) comprising a cathode (201), an anode (203) and an electrolyte (202) interposed between the cathode (201) and the anode (203), the elementary electrochemical cell (200) being interposed between the interconnectors (100).

7. Stack (300) according to the preceding claim comprising a clearance X corresponding to the distance between the lower face (3) of a folded edge (6) of a separation plate (1) of a first interconnector (100) and the upper face (2) of a folded edge (6) of a separation plate (1) of a second interconnector (100), which is adjacent to the first interconnector (100), the clearance (X), being equal to E + E.cos (A) - D.cos(A), E being the thickness of the separation plate (1) and D being the distance between the lower face (3) of the central part (5) of the separation plate (1) of the first interconnector (100) and the upper face (2) of the central part (5) of the separation plate (1) of the second interconnector (100).

8. Stack (300) according to any one of the two preceding claims wherein the folded edge (6) of a first interconnector (100) and the folded edge (6) of a second interconnector (100) are parallel.

9. Stack (300) according to any one of claims 6 to 8 comprising a gas-tight bead (301) arranged at least partially between the lower face (3) of a folded edge (6) of a separation plate (1) of a first interconnector (100) and the upper face (2) of a folded edge (6) of a separation plate (1) of a second interconnector (100).

10. Stack (300) according to any one of claims 6 to 9 comprising at least one shim (302) arranged at least partially between the lower face (3) of a folded edge (6) of a separation plate (1) of a first interconnector (100) and the upper face (2) of a folded edge (6) of a separation plate (1) of a second interconnector (100).

11. Stack (300) according to any one of claims 6 to 10 comprising an electrically and / or thermally insulating material arranged at least partially between the lower face (3) of a folded edge (6) of a separation plate (1) of a first interconnector (100) and the upper face (2) of a folded edge (6) of a separation plate (1) of a second interconnector (100).

12. Stack according to any one of claims 6 to 11 comprising an electrically conductive material arranged at least partially between the lower face (3) of a folded edge (6) of a separation plate (1) of a first interconnector (100) and the upper face (2) of a folded edge (6) of a separation plate (1) of a second interconnector (100).

13. A solid oxide electrolyzer comprising a stack according to any one of claims 6 to 12 and an upper end plate (312) and a lower end plate (311).

14. A method of manufacturing an interconnector for a solid oxide stack according to any one of claims 1 to 5, comprising a step of stacking the upper plate (101) on the upper face (2) of the separation plate (1). and the lower plate (102) on the lower face (3) of the separation plate (1) then a step of welding the plates characterized in that it comprises a step of stamping by a stamping die of the separation plate (1) to form the folded edge (6) before stacking or after stacking and before the welding step.

15. Manufacturing method according to the preceding claim comprising a step of ceramic deposition on the edge of the separation plate (1), intended to form the folded edge (6), before the stamping step.

16. Manufacturing method according to the preceding claim in which the ceramic deposit has a thickness of between 50 and 100 pm.

17. Method for manufacturing a stack (300) comprising, after the method for manufacturing an interconnector according to any one of claims 14 to 16, a step of assembling an elementary electrochemical cell (200) comprising a cathode (201), an anode (203) and an electrolyte (202) intercalated between the cathode (201) and the anode (203) between two interconnectors (100) according to any one of claims 1 to 5.

18. Method for manufacturing a stack (300) according to the preceding claim comprising repeating the assembly step to form a stack (300) comprising a plurality of electrochemical cells (200) each interposed between two interconnectors (100).

19. Method for manufacturing a stack (300) according to any one of claims 17 and 18 comprising a step of functionalizing a clearance X formed between the lower face (3) of a folded edge (6) of a separation plate (1) of a first interconnector (100) and the upper face (2) of a folded edge (6) of a separation plate (1) of a second interconnector (100).

20. Method for manufacturing a stack (300) according to the preceding claim in which the functionalization step comprises the placement of a wedge (302) of glass strip glued to the folded edge (6).

21. Method for manufacturing an electrolyser (500) comprising, after the method for manufacturing a stack according to any one of claims 17 to 19, a step of positioning an upper end plate (312) and a lower end plate (313) at the ends of the stack (300) according to any one of claims 6 to 12.

22. Method for manufacturing an electrolyser (500) according to the preceding claim comprising a step of compressing the stack (300) between the upper terminal plate (312) and lower terminal plate (313).

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