Stack comprising a monolithic electrical and fluidic interconnect plate and glass-ceramic seals

Abstract

The present disclosure relates to an electrical and fluidic interconnector (8, 20-23) for a high-temperature electrolysis cell or for an SOFC-type fuel cell, the interconnector comprising: - a monolithic interconnect plate (8, 8i, 8i+1) comprising supply through-openings in the vicinity of each edge, as well as two through-slots that are formed near two opposite edges, the supply openings and the slots allowing the supply of gas to the electrochemical cells; - an LSM layer (15) and a gate (16) on a first face and a second face of the interconnect plate, respectively; and - seals (20-23) attached to the first face of the interconnect plate and configured so as to define gas circulation compartments.

Description

[0001] DESCRIPTION

[0002] TITLE: Stack comprising a monolithic electrical and fluidic interconnection plate and glass-ceramic seals

[0003] TECHNICAL FIELD

[0004] The present invention relates to the field of high-temperature electrolysis of water or carbon dioxide CO₂ (HTE, or EVHT for high-temperature steam electrolysis, or HTE, English acronym for "High Temperature Electrolysis", or HTSE, English acronym for "High Temperature Steam Electrolysis") and of co-electrolysis of water also at high temperature with carbon dioxide CO₂.

[0005] The present invention also relates to the field of solid oxide fuel cells (SOFCs, English acronym for Solid Oxide Fuel Cell).

[0006] The invention relates more particularly to a new realization of an electrical and fluidic interconnector within a high temperature electrolysis or co-electrolysis reactor (EHT), or of a SOFC stack of elementary electrochemical cells.

[0007] It should be noted here that electrical and fluidic interconnectors are devices that ensure the electrical series connection of each electrochemical cell in a stack of EHT reactors or SOFC fuel cells. These interconnectors also provide a fluidic connection, allowing the combined output of each of the reactor's elementary cells. Specifically, the interconnectors perform the functions of current supply and collection and define gas circulation chambers (distribution and / or collection).

[0008] STATE OF THE ART

[0009] Water electrolysis is usually carried out at high temperatures, typically between 600 and 1000°C, so that some of the energy required for the reaction is supplied by heat. Furthermore, the reaction is more efficiently activated at high temperatures. To implement high-temperature electrolysis, a SOEC (Solid Oxide Electrolyte Cell) type electrolyzer is commonly used. This consists of a stack of elementary units, each containing a solid oxide electrolysis cell and metal alloy interconnectors (also called bipolar plates or interconnecting plates). Each solid oxide electrolysis cell comprises three stacked anode / electrolyte / cathode layers.

[0010] A solid oxide fuel cell (SOFC) is also made up of the same type of stack of elementary units. The interconnectors serve to ensure both the passage of electric current and the circulation of gases in the vicinity of each cell (injected water vapor, hydrogen and oxygen extracted in an EHT electrolyzer; injected air and fuel including hydrogen and extracted water in an SOFC) and to separate the anodic and cathodic compartments, which are the gas circulation compartments on the anode and cathode sides of the cells respectively.

[0011] To perform high-temperature steam electrolysis (HTE), water vapor (H₂O) is injected into the cathode compartment. Under the influence of the current applied to the cell, the dissociation of water molecules into vapor occurs at the interface between the hydrogen electrode (cathode) and the electrolyte: this dissociation produces hydrogen gas (H₂O) and oxygen ions. The hydrogen gas is collected and discharged from the hydrogen compartment. The oxygen ions (O₂) 2 ' migrate through the electrolyte and recombine into dioxygen at the interface between the electrolyte and the oxygen electrode (anode). A draining gas, such as air, can circulate at the anode and thus collect the oxygen generated in gaseous form at the anode.

[0012] To operate a SOFC fuel cell, air (oxygen) is injected into the cathode compartment of the cell and hydrogen (or water vapor) is injected into the anodic compartment. The oxygen from the air dissociates into O₂ ions 2 ', which migrate in the electrolyte from the cathode to the anode to oxidize hydrogen and form water, with simultaneous production of electricity. In SOFC cells, as in SOEC electrolysis, water vapor is found in the H compartment.

[0013] Since the operating conditions of an EHT electrolyzer are very similar to those of a SOFC fuel cell, the same technological constraints apply. These constraints primarily involve the mechanical resistance to temperature and thermal cycling of a stack of different materials (ceramics and metallic alloy), maintaining the seal between the anodic and cathodic compartments, the aging resistance of the metallic interconnectors, and minimizing ohmic losses at various stack interfaces. A significant constraint is to optimally manage the thermal operating regimes of a fuel cell (SOFC), in which the overall reaction is exothermic, or of an electrolyzer (EHT), where the overall reaction can be either exothermic or endothermic depending on the operating potential.

[0014] Therefore, in document EP3183379, a device forming an electrical and fluidic interconnector was proposed, comprising three substantially flat sheets welded together and with through holes formed in them to allow the electrical and fluidic connection of elementary cells. The thinness of the sheets, however, imposes significant manufacturing constraints, requiring very precise control of the manufacturing processes to guarantee the geometry of the components (flatness / straightness) and to avoid, or at least minimize, the presence of gaps between the sheets, in order to ensure mechanical transfer of electrical contacts within the stack.The welding of the sheet metal is also critical: the welding process can generate significant sheet metal deformations that are detrimental to maintaining the flatness of the interconnectors within acceptable tolerance ranges for a stacked assembly and that can break electrical continuity in the assembly. Furthermore, the welding process generates residual stresses in the sheet metal, which are inherent to the process and necessitate the implementation of stress-relieving annealing and weld leak testing.

[0015] However, despite these additional steps, which are costly and time-consuming to implement, a large number of flatness or sealing defects are observed, leading to a high rate of rejection for non-conformity.

[0016] EXPOSED

[0017] One aim of the present application is to remedy the aforementioned disadvantages, by proposing an electrical and fluidic interconnector and a device comprising such an interconnector and at least one elementary electrochemical cell, in particular for the electrolysis of water at high temperature, the co-electrolysis of water also at high temperature with carbon dioxide CO₂ or for a solid oxide fuel cell, which is simpler to manufacture while ensuring better electrical continuity in a stack comprising such an interconnector and sealing of the gas circulation chambers.

[0018] To this end, a first aspect proposes an electrical and fluidic interconnector for a reactor for the electrolysis of water or carbon dioxide (CO₂) at high temperature, for the co-electrolysis of water also at high temperature with carbon dioxide (CO₂), or for a solid oxide fuel cell comprising:

[0019] - a monolithic interconnection plate, the interconnection plate having a first face, a second face opposite the first face, the first face and the second face being connected by a border comprising two first opposite edges and two second opposite edges, at least one through-feed light being formed in the interconnection plate near each edge and at least two through-feed slots being formed in the interconnection plate near the two second edges, the feed lights and the slots opening into the first and second faces of the interconnection plate;

[0020] - a first contact layer, fixed on the first face and configured to come into surface contact with a first electrode of a first elementary electrochemical cell;

[0021] - a second contact layer, fixed on the second face and configured to come into surface contact with a second electrode of a second elementary electrochemical cell;

[0022] a first of the supply lights being configured to receive a first gas, a second of the supply lights being in fluidic communication with the first of the supply lights via the first contact layer and being configured to receive the first gas,

[0023] a third of the power lights being configured to receive a second gas, and

[0024] a fourth of the supply lights being in fluidic communication with the third of the supply lights via the second contact layer and being configured to receive the second gas; and

[0025] - joints fixed on the first face, so that the interconnecting plate, the supply lights, the slots and the joints together delimit first and second gas circulation compartments.

[0026] Some preferred but not limiting characteristics of the electrical and fluidic interconnector according to the first aspect are the following, taken individually or in combination:

[0027] - the joints are made of at least one of the following materials: glass, glass-ceramic;

[0028] - the joints each include at least one peripheral joint fixed on the first face and the second face of the interconnecting plate, respectively, so as to continuously surround the first contact layer and the second contact layer, respectively;

[0029] - the seals further include a sub-cell seal fixed continuously along the periphery of the first contact layer, the sub-cell seal being disposed on the first face between the slots and the peripheral seal and being configured to bear against the first electrode of the first elementary electrochemical cell;

[0030] - the sub-cell seal comprises two first sides parallel to the slots and two second sides perpendicular to the slots, and the seals further comprise two sealing cords fixed each along one of the second sides of the sub-cell seal by connecting the two first sides of the sub-cell seal;

[0031] - each feed light comprises two opposite end edges, the joints further comprising formwork joints extending from the sub-cell joint to a respective end edge, the formwork joints connected to the end edges of adjacent feed lights being able to be further connected to each other along the sub-cell joint and have a thickness at least equal to a sum of a thickness of the sub-cell joint and a thickness of the first elementary electrochemical cell;

[0032] - the formwork joints which extend on either side of a supply light located near a second edge are further connected together and have a thickness at least equal to a sum of a thickness of the sub-cell joint and a thickness of the first elementary electrochemical cell so that each formwork joint is configured to come abutting against an edge of the first elementary electrochemical cell when the second electrode of the first elementary electronic cell is in surface contact against the second contact layer of an additional interconnecting plate;

[0033] - the electrical and fluidic interconnector further includes additional seals fixed at least partially to the second electrode of the elementary electrochemical cell, the additional seals comprising two barrier seals each comprising: a first portion extending continuously along a second associated edge to the feed lights which are adjacent to the first edges of the interconnecting plate; and two second portions each extending continuously between the first portion and the feed light which is adjacent to the second edge,

[0034] the first portion of the barrier seals being positioned on the cell so that a gap is located between the first portion and the second associated edge;

[0035] - each barrier joint is further fixed to all or part of the formwork joints; and / or - the additional joints further comprise two sealing strips configured to be fixed each to the second electrode of the first elementary electrochemical cell so as to extend along the first portion of a respective barrier joint, between the two second portions of the barrier joint, the sealing strips being made of a non-porous gas material.

[0036] According to a second aspect, a stacking is proposed comprising a stacking layer consisting of:

[0037] - an electrical and fluidic interconnector according to the first aspect; and

[0038] - an elementary electrochemical cell comprising a first electrode, an electrolyte and a second electrode, the first electrode of the elementary electrochemical cell being in contact with the first contact layer and the joints of the electrical and fluidic interconnector.

[0039] Some preferred but not limiting characteristics of stacking according to the second aspect are the following, taken individually or in combination:

[0040] - the stack further includes an additional electrical and fluidic interconnector conforming to the first aspect, the second electrode of the elementary electrochemical cell being supported against the second contact layer of the additional electrical and fluidic interconnector by means of additional seals;

[0041] - the stack further includes an additional elementary electrochemical cell comprising a first electrode, an electrolyte and a second electrode, the first electrode of the additional elementary electrochemical cell being in contact with the first contact layer of the additional electrical and fluidic interconnector via additional seals;

[0042] - Additional joints include a sub-cell seal, sealing cords and / or formwork joints;

[0043] - the stack further comprises a junction plate made of an electrically insulating material, the junction plate comprising a peripheral edge fixed to at least part of the joints extending at a distance from the first face of the interconnecting plate; and / or

[0044] - the stack further includes pads fixed to the first face of the interconnection plate by being adjacent to an associated power light, the junction plate comprising as many tabs as pads, each tab being fixed to a respective pad partially masking the associated power light.

[0045] According to a third aspect, a manufacturing process for a stack is proposed according to the second aspect, comprising the following steps:

[0046] - formation of a stacking layer according to the following sub-steps: - supply of an interconnecting plate having the first and second faces, the feed lights, the slots and the first and second contact layers;

[0047] - deposition of a vitreous material on the first face of the interconnecting plate; - placement of the elementary electrochemical cell against the first contact layer so that the first electrode comes into contact with the vitreous material; and - heat treatment of the stacking layer formed by the interconnecting plate, the vitreous material and the elementary electrochemical cell so as to transform the vitreous material into seals and to fix the elementary electrochemical cell on the interconnecting plate.

[0048] Some preferred but not limiting characteristics of the manufacturing process for a stack, the third aspect, are as follows, taken individually or in combination:

[0049] - the process further includes, prior to the heat treatment step, an additional step of depositing a glassy material on the elementary electrochemical cell so as to form additional seals;

[0050] - the process further includes placing a junction plate on the glassy material, around the elementary electrochemical cell and at a distance from the first face of the interconnecting plate, prior to the heat treatment step;

[0051] - the process further includes, prior to the heat treatment step, the following steps: formation of an additional stacking layer comprising an additional interconnecting plate and an additional elementary electrochemical cell; and placement of the second face of the additional interconnecting plate of the additional stacking layer on the junction plate.

[0052] DESCRIPTION OF THE FIGURES

[0053] Other features, purposes, and advantages of the presentation will become apparent from the following description, which is purely illustrative and not exhaustive, and should be read in conjunction with the attached drawings on which:

[0054] Figure 1 schematically illustrates the air face of an example of an electrical and fluidic interconnector conforming to a first embodiment;

[0055] Figure 2 represents an example of a stacking layer comprising the electrical and fluidic interconnector of Figure 1 and an elementary electrochemical cell, placed on the air face of the interconnector;

[0056] Figure 3 schematically illustrates an example of a stacking layer comprising an electrical and fluidic interconnector and an elementary electrochemical cell placed on the fuel face side of the interconnector;

[0057] Figure 4 is a partial cross-sectional view along axis AA of Figure 3 and a perspective view of stacking layer 3;

[0058] Figure 5 is a top view of the stacking layer of Figure 4 further comprising a junction plate placed on the air face of the electrical and fluidic interconnector;

[0059] Figure 6 is a partial cross-sectional and perspective view of an example stacking conforming to an embodiment comprising three stacking layers, on which the circulation of a first gas flow has been shown;

[0060] Figure 7 is a cross-sectional view of an example of a stacking conforming to an embodiment comprising two stacking layers, on which the circulation of a second gas flow has been shown; and

[0061] Figure 8 is a flowchart of steps of an example of a manufacturing process according to one embodiment.

[0062] Across all figures, similar elements bear identical references.

[0063] DETAILED DESCRIPTION

[0064] In this paper, an electrical and fluidic interconnector for a steam electrolysis reactor (SER) will be described in more detail. However, this paper is not limited to such a reactor and applies mutatis mutandis to a steam co-electrolysis reactor, or even to a solid oxide fuel cell (SOFC), the only difference being the reactant or draining gases and the electrochemical half-reactions.

[0065] Furthermore, the electrolyzers and all the fuel cells described here are of the solid oxide type (SOEC, acronym for "Solid Oxide Electrolyte Cell" or SOFC, "Solid Oxide Fuel Cell") and operate at high temperatures. Thus, all the components (first electrode 4 / electrolyte 6 / second electrode 5) of an electrochemical cell 3 are ceramics. The high operating temperature of an electrolyzer (electrolysis reactor) is typically between 600°C and 1000°C, for example, between 680°C and 850°C.

[0066] A water electrolyzer is an electrochemical device for producing hydrogen (and oxygen) under the effect of an electric current.

[0067] In high-temperature electrolyzers (HTEs), the electrolysis of water at high temperature is carried out using water vapor. The function of a high-temperature electrolyzer (HTE) is to transform water vapor into hydrogen and oxygen according to the following reaction: 2 H₂O → 2 H₂ + O₂.

[0068] This reaction is carried out electrochemically in the cells 3 of the electrolyzer. Each elementary electrolysis cell 3 consists of an anode 4 and a cathode 5, positioned on either side of a solid electrolyte 6, generally in the form of a membrane. The two electrodes (anode 4 and cathode 5) are electronic conductors made of porous material, and the electrolyte 6 is gas-tight, an electronic insulator, and an ionic conductor. The electrolyte 6 can, in particular, be an anionic conductor, more precisely an anionic conductor of O₂ ions. 2 ' and the electrolyzer is then called an anionic electrolyzer.

[0069] Electrochemical reactions take place at the interface between each of the electronic conductors and the ionic conductor.

[0070] At cathode 5, the half-reaction is as follows: 2 H2O + 4 e' → 2 H2O + 2 O 2 '.

[0071] At anode 4, the half-reaction is as follows: 2 O 2 '— > O2 + 4 e'.

[0072] Electrolyte 6, intercalated between the two electrodes, is the site of migration of O ions. 2 ' under the effect of the electric field created by the potential difference imposed between the anode 4 and the cathode 5.

[0073] By way of non-limiting example, an elementary SOEC electrochemical cell 3 that can be implemented in a reactor conforming to this description may, in particular, be of the cathode support (CSC) type and may have the following characteristics:

[0074] Cathode 5

[0075] Ni-YSZ constituent material

[0076] Thickness 315 pm

[0077] Thermal conductivity 13.1 W / m 1 .K' 1

[0078] Electrical conductivity 10 5 Q' 1 .m' 1

[0079] Porosity 0.37

[0080] Permeability 10' 13 m 2

[0081] Tortuosity 4

[0082] Current density 5300 Am' 2

[0083] Anode 4

[0084] LSM constituent material

[0085] Thickness 20 pm

[0086] Thermal conductivity 9.6 W / m 1 .K' 1

[0087] Electrical conductivity 10 4 Q- 1 .m' 1

[0088] Porosity 0.37

[0089] Permeability 10' 13 m 2

[0090] Tortuosity 4

[0091] Current density 2000 Am' 2

[0092] Electrolyte

[0093] YSZ constituent material

[0094] Thickness 3-12 pm

[0095]

[0096] Thermal conductivity 0.42 W / m 1 .K' 1

[0097] Electrical conductivity 10 4 Q' 1 .m' 1

[0098]

[0099] The water vapor entering cathode 5 may be accompanied by hydrogen (H₂), and the hydrogen produced and recovered at the outlet may be accompanied by water vapor. Similarly, a draining gas, such as air, can also be injected at the inlet to remove the oxygen produced. The injection of a draining gas also serves as a thermal regulator.

[0100] An elementary reactor consists of an elementary electrochemical cell 3 as described above, comprising an electrolyte 6 placed between a cathode 5 and an anode 4, sandwiched between two interconnectors 7 which provide the electrical, hydraulic and thermal distribution functions.

[0101] To increase the flow rates of hydrogen and oxygen produced, it is known to stack several elementary electrolysis cells 3 on top of each other, separating them with interconnectors 7 to obtain a stack 1 (e.g., of electrolysis). The assembly is positioned between two end interconnection plates that support the electrical and gas supplies of the electrolyzer.

[0102] A high-temperature water electrolyzer (HTW) thus comprises at least one, usually a plurality of electrolysis cells 3 stacked one on top of the other, each elementary cell 3 being formed of an electrolyte 6, a cathode 5 and an anode 4, the electrolyte 6 being intercalated between the anode 4 and the cathode 5.

[0103] The 7 fluidic and electrical interconnectors which are in electrical contact with one or more electrodes and generally ensure the functions of supplying and collecting electrical current and delimit one or more gas circulation compartments.

[0104] Thus, a so-called cathodic compartment has the function of distributing electric current and water vapor as well as recovering hydrogen at the cathode 5 in contact.

[0105] An anodic compartment has the function of distributing the electric current and recovering the oxygen produced at the anode 4 in contact, possibly with the help of a draining gas.

[0106] Satisfactory reactor operation requires:

[0107] - good electrical contact and sufficient contact surfaces (covering the active areas on both sides of cell 3) between each cell 3 and interconnector 7, in order to obtain the lowest ohmic resistance between cell 3 and interconnectors 7;

[0108] - a good seal between the two separate compartments otherwise the gases produced will recombine, leading to a decrease in efficiency and, above all, the appearance of hot spots damaging the electrolyzer;

[0109] - good gas distribution both at the inlet and during the recovery of produced gases, otherwise there will be loss of efficiency, inhomogeneity of pressure and temperature within the different elementary cells, or even prohibitive damage to the cells; and

[0110] - good electrical insulation between two adjacent interconnectors 7 in stack 1 outside the active zone of cell 3, otherwise the current supply to the elementary electrolysis cell 3 interposed between the two interconnectors 7 will be reduced.

[0111] In order to obtain a reactor, for example an electrolyzer, with good efficiency, the electrical interconnectors 7 include a monolithic interconnection plate 8, on which the sealing and fixing of the cells 3 is achieved using seals judiciously positioned on the faces of the interconnectors 7 and the cells 3, which makes it possible to ensure both good electrical contact between the interconnectors 7 and the cells 3 and good sealing between the compartments.

[0112] For this purpose, interconnector 7 includes:

[0113] - a monolithic metallic interconnection plate 8;

[0114] - contact layers 15, 16; and

[0115] - 20-25 seals fixed on the interconnection plate 8 and the cells 3.

[0116] As we will see later, the application of gaskets 20-25 to the interconnecting plate 8 eliminates the need for added and welded parts on the interconnecting plate, thus preventing deformations induced by the welding process. The flatness of the interconnecting plate 8 is therefore better controlled, which not only simplifies the manufacturing process (eliminating residual stresses and thus the holding step, simplifying acceptance testing (leak tightness)), but also significantly reduces the scrap rate and cost.

[0117] The interconnecting plate 8 has a first face 9, or air face, and a second face 10, or fuel face, which are connected by a rim. The plate 8 can have any suitable shape and comprises two opposing first edges 11 and two opposing second edges 12. In one embodiment, the plate 8 can be generally parallelepiped-shaped such that the two first edges 11 are parallel to each other and the two second edges 12 are parallel to each other. The plate 8 can, in particular, be made of at least one of the following materials: ferric stainless steel type 1.4509 X2CrTiNb18 or 1.4760 X1CrTiLa22 and have a thickness between 0.2 mm and 0.6 mm. The air face 9 and fuel face 10 are substantially flat over their entire surface and are substantially smooth. The flatness tolerance of the plate 8 is between 10 and 50 µm. The air 9 and fuel 10 faces have an arithmetic mean roughness Ra of less than 0.8.

[0118] At least one feed port 13 is formed in the interconnecting plate 8 near each edge 11, 12. The ports 13 are through-ports, meaning they open into the air face 9 and the fuel face 10 of the plate 8. Each port may, for example, have a generally elongated shape and extend substantially parallel to one of the edges 11, 12 of the plate 8. Alternatively, the feed ports 13 may be ovoid, for example oval or circular. The feed ports 13 may be continuous or include one or more discontinuous sections along the edge. Each has two opposing end (or lateral) edges located near the second edges 12 of the plate 8.

[0119] The plate 8 further includes at least two through slots 14 near the two second edges 12 and a corresponding feed light 13. The slots 14 may, for example, have a generally elongated shape and extend substantially parallel to the second edge 12. The slots 14 may be continuous or include one or more discontinuous sections along the edge. In one embodiment, the cross-sectional area of ​​the slots 14 is smaller than the cross-sectional area of ​​the feed lights 13.

[0120] The slots 14 are positioned radially inside relative to the power supply lights 13. In other words, the power supply lights 13 are closer to the edges 11, 12 of the plate 8 than the slots 14.

[0121] The plate 8 further comprises a first contact layer 15 fixed to the air face 9 and a second contact layer 16 fixed to the fuel face 10. The first contact layer 15 may include a conductive ceramic layer, typically made of lanthanum strontium manganite (LSM) ceramic, and is configured to make surface contact with the anode 4 of a first electrochemical cell 3. The second contact layer 16 may include a metallic grid 16 (made of nickel, gold, etc.) and is configured to make surface contact with the cathode 5 of a second electrochemical cell 3. Examples of LSM ceramic layers 15 and grids 16 are described in document FR1259040.

[0122] In operation, the supply ports 13 adjacent to the first edges 11 allow the circulation (distribution and / or collection) of a first gas, for example, water vapor, while the supply ports 13 adjacent to the second edges 12 and the slots 14 allow the circulation (distribution and / or collection) of a second gas, for example, air. The water vapor passes through the metallic grid 16, where the chemical reaction with the cathode 5 occurs to produce hydrogen (H₂), while the air passes through the LSM ceramic 15, where the chemical reaction at the anode 4 occurs to produce oxygen.

[0123] For the sake of simplicity, the power lights 13 parallel to the first edges 11 of the plate 8 will be referred to hereafter as "lights 13 H?" and the power lights 13 parallel to the second edges 12 are referred to hereafter as "lights 13 0?".

[0124] The interconnection plate 8 further includes seals 20-25 fixed on the air face 9 and configured to delimit, with the elementary electrochemical cell 3, the compartments for the circulation of gases O? and H?.

[0125] The 20-25 joints can notably be made of at least one of the following materials: glass, glass-ceramic.

[0126] Face air 9

[0127] The 20-25 seals fixed to the air face 9 may include at least one of the following seals:

[0128] - a peripheral seal 20, configured to create a seal around the first elementary electrochemical cell 3 and confine the airflow;

[0129] - a sub-cell 21 joint, configured to receive the first cell 3;

[0130] - sealing cords 22; and

[0131] - 23 formwork joints, configured to isolate the air compartment and water vapor compartment.

[0132] More specifically, the peripheral seal 20 is fixed to the air face 9, around the LSM ceramic layer 15. The peripheral seal 20 is continuous, meaning it follows the perimeter of the LSM ceramic layer 15 continuously to form an external barrier. It should be noted, however, that the peripheral seal 20 may consist of several seal sections placed end-to-end or side-by-side with overlap, so as to ultimately obtain a continuous seal. It is therefore not necessarily formed from a single piece.

[0133] The peripheral seal 20 can have any suitable shape, for example a parallelepiped, circular or any other shape. The peripheral seal 20 can in particular have the form of one or more beads (i.e. a single bead surrounding the LSM ceramic layer 15 or several beads positioned side by side on the air face 9, with or without spacing).

[0134] The thickness of the peripheral seal 20 is preferably constant and slightly greater than the spacing between two adjacent interconnecting plates 8 in the final stack 1 (i.e., after compression and heat treatment, see step S6 described below). Such a thickness ensures mechanical support of the interconnecting plates 8 before the formation of the glass-ceramic seal, without the compressive force being transmitted at room temperature through the contact layers to the elementary electrochemical cell 3. To guarantee this, the height of the peripheral seals 20 plus that of the connecting plate 17 must be greater than the sum of the thicknesses of the cell 3, the seals (21, 22, described below) located beneath the cell 3, and the grid 16.In terms of thickness, the difference between the sum of the heights of the peripheral seals 20 and the junction plate 17 and the sum of the heights of cell 3, seals 21, 22 and the LSM ceramic layer 15 is on the order of 100 to 500 µm. This difference is determined taking into account the flatness tolerances of the interconnector plate 8 and the reduction in thickness of the glass seal during its hot forming.

[0135] The sub-cell seal 21 is fixed on the air face 9, along the perimeter of the LSM ceramic layer 15, between the slots 14 and the peripheral seal 20. The sub-cell seal 21 therefore does not cover the slots 14 but extends on the outside of them relative to cell 3.

[0136] The sub-cell seal 21 is continuous, that is to say it follows the perimeter of the LSM 15 ceramic layer continuously in order to form an internal barrier and ensure a seal of the external perimeter of cell 3. It therefore delimits the air circulation chamber above the LSM 15 ceramic layer. It is configured to bear against the anode 4 of the first elementary electrochemical cell 3 and ensure an internal inter-chamber seal.

[0137] The sub-cell joint 21 may have a shape similar (in the sense of homotheties) to the shape of cell 3, for example a parallelepiped shape. Thus, the sub-cell joint 21 may comprise two first sides parallel to the slots 14 and the second edges 12 of the plate 8 and two second sides perpendicular to the slots 14 and the first edges 11 of the plate 8, the two second sides being positioned between one end of the slots 14 and the associated first edge 11.

[0138] The bead forming the sub-cell seal 21 can be deposited directly onto the air face 9 and / or the anode 4 of cell 3, before their assembly in the stack. Since the flatness of the interconnector 7 plate 8 is ensured by its monobloc structure and is no longer dependent on welds, the possibility of a precise and controlled deposition of this sub-cell seal 21 is technically simpler to implement.

[0139] A thickness of the sub-cell seal 21 is chosen so that the first cell 3 comes into contact with both the sub-cell seal 21 and the LSM ceramic layer 15, for example slightly greater than the thickness of the LSM ceramic layer 15. In this way, at cold before melting of the sub-cell seal 21, the cell 3 does not come into contact with the LSM ceramic layer 15.

[0140] The sealing cords 22 are fixed along the sub-cell gasket 21, inside the sub-cell gasket 21, and are configured to limit the passage of gases out of the active zone of the cell 3. These sealing cords 22 are optional, but their absence results in a decrease in the electrolyzer's performance. Therefore, each sealing cord 22 is fixed at a distance from the slots 14 and connects two opposite edges of the sub-cell gasket 21, on the side of a first associated edge 11 of the plate 8. The sealing cords 22 are thus positioned between one end of the slots 14 and the first associated edge 11.

[0141] In the example of a sub-cell seal 21 described above, the sealing cords 22 therefore connect the first two sides of the sub-cell seal 21.

[0142] The thickness of the sealing cords 22 is substantially equal to the thickness of the sub-cell seal 21, so that the first cell 3 comes into contact with the sealing cords when it is placed against the LSM ceramic layer 15. For example, a difference between the thickness of the sealing cords 22 and the thickness of the sub-cell seal 21 is between 100 and 150 micrometers, which ensures a suitable docking stroke during manufacturing.

[0143] The formwork joints 23 extend from the sub-cell joint 21 to a respective end edge of a supply light 13 and are configured to laterally delimit the gas compartments. The plate 8 therefore comprises twice as many formwork joints 23 as supply lights 13 (one formwork joint 23 per end edge).

[0144] The formwork joints 23 may have a thickness at least equal to a sum of a thickness of the sub-cell joint 21 and a thickness of the cell 3, so as to come into contact with the outer perimeter of the cell 3 when the anode 4 of the cell 3 is in surface contact with the ceramic layer LSM 15.

[0145] In one embodiment, each formwork joint 23 extends substantially parallel to one of the edges 11, 12 of the plate 8, between the sub-cell joint 21 and the end edge of the associated light.

[0146] If necessary, the formwork joints 23 connected to the adjacent end edges of a light 13 H? and a light 13 0? can also be connected to each other along the sub-cell joint 21. In this configuration, the plate 8 therefore comprises eight formwork joints 23 connected in pairs along the sub-cell joint 21 so as to form four sets of formwork joints 23. For example, each set of formwork joints 23 can comprise a guide section 0? 23a connected to an end edge of a light 13 0?, a guide section H? 23b to the end edge nearest to the light 13 H? immediately adjacent to the end edge of the light 130?, and an angled section 23c which follows the shape of the sub-cell joint 21 (extending between the sub-cell joint 21 and the edges 11, 12 of the plate 8), between the guide sections 0? and H? 23a, 23b of the assembly.This configuration improves the sealing of the gas compartments as well as the positioning of the first cell 3 on the interconnection plate 8.

[0147] To further improve the sealing of the gas compartments, the two assemblies of formwork seals 23 extending on either side of a light 130 can also be connected by a blocking section 23d. The blocking section 23d then extends along the sub-cell seal 21, between the sub-cell seal 21 and the associated light 130.

[0148] It should be noted that the sub-cell seal 21, the sealing cords 22 and the formwork seals 23 can be obtained in a manner analogous to the peripheral seal 20 and can comprise a single or multiple glass-ceramic cord or a glass-ceramic strip.

[0149] Face fuel 10

[0150] The 20-25 seals may also include fuel-side seals 10, which may include at least one of the following seals:

[0151] - a peripheral seal 20, configured to create a seal around a second elementary electrochemical cell 3 and confine the airflow;

[0152] - barrier seals 24 configured to guide the gases from compartment H? (water vapor and H?) along the grid 16; and

[0153] - sealing strips 25 configured to prevent the introduction of oxygen into the cathode 5 of the second cell 3.

[0154] The peripheral seal 20 is fixed to the fuel face 10, around the grid 16. The peripheral seal 20 of the fuel face 10 has the same properties (continuity, shape, manufacturing process) as the peripheral seal 20 of the air face 9. In one embodiment, the peripheral seal 20 of the fuel face 10 is identical to the peripheral seal 20 of the air face 9 and is fixed to the air face 9 so as to extend exactly opposite the peripheral seal 20 of the air face 9. Two barrier seals 24 configured to guide the oxygen flow from the oxygen supply lumen 13 to the immediately adjacent slot 14 are also placed on the side of the fuel face 10. For this purpose, the barrier seals 24 can, for example, be fixed in whole or in part to the cathode 5 of the second cell 3.As will be detailed later, air enters a 130° opening in a given interconnecting plate 8 but is prevented by the barrier seal 24 from entering the grid 16 of this interconnecting plate 8. It is then guided by the barrier seal 24 towards the slot 14 of the immediately adjacent interconnecting plate 8 in the stack. Therefore, the portion of air entering the 130° opening in the interconnecting plate 8 does not pass through the slot 14 of this interconnecting plate 8.

[0155] In one embodiment, each barrier joint 24 comprises a longitudinal portion 24a extending continuously along a second associated edge 12 to an end edge of the openings 13H?, two transverse portions 24b each extending continuously between the longitudinal portion 24a and the end edges of the opening 13H?, and two transverse portions 24c each extending continuously between the longitudinal portion 24a and the end edges of the opening 13H? so as to delimit the gas compartments. Thus, the portion of air entering the opening 13H? is guided by the transverse portions 24b of the barrier joint 24 towards the longitudinal portion 24a and comes to rest against this longitudinal portion 24a.When the interconnector 7 is mounted in the stack 1 with the cells 3, the portion of air is thus forced by the barrier seal 24 to rise towards the slot 14 of the interconnecting plate 8 of the immediately adjacent interconnector 7. Similarly, the portion of the gaseous mixture of water vapor and H₂ entering the H₂O lumen 13 is guided by the transverse portions 24c of the barrier seal 24 towards the cathode 5.

[0156] Each barrier seal 24 extends radially inward relative to the slots 14. The slots 14 are therefore located between the barrier seal 24 and the associated opening 130. Each barrier seal 24 is also continuous.

[0157] In one embodiment, the longitudinal portion 24a of the barrier joint 24 can be fixed to the cathode 5 of the second cell 3, along its edge, and extend to cover the formwork joint 23 up to the end edges of the opening 13 H?. The lateral portions, for their part, can be fixed to the cell 3 and extend to cover the formwork joint 23 up to the end edges opposite the opening 130?. The lateral portions 24b, 24c can, in particular, cover the guide sections 0? and H223a, 23b and, where applicable, the angled section 23c of the formwork joints 23. Where applicable, the barrier joints 24 can be placed on the cathode 5 of the second cell 3 and the formwork joints 23 after the second cell 3 has been mounted on the interconnecting plate 8.

[0158] The barrier joints 24 may for example have a thickness slightly greater than the thickness of the grid 16, for example 0.1 mm to 0.2 mm greater than the thickness of the grid 16.

[0159] The two sealing strips 25 are fixed to the cathode 5 of the second elementary electrochemical cell 3 so as to cover the cathode 5 along the longitudinal portion 24a with a respective barrier seal 24, between the two lateral portions 24b of the barrier seal 24. Since the sealing strips 25 are made of a gas-impermeable material, they prevent the portion of air entering through the adjacent aperture 130 from passing through the cell 3 and the grid 16, forcing it to rise towards the slot 14 of the immediately adjacent plate 8. In the same way, these sealing strips 25 prevent the passage of gases from compartment H into compartment O.

[0160] The sealing strips 25 are therefore sized and positioned on cell 3 so as to cover the entire surface of cell 3 extending between the barrier joint 24 and the associated opening 130, thus forming a formwork over the porous cell 3 on the fuel face side 10. If necessary, the sealing strips 25 can extend laterally beyond cell 3, towards the opening 130, so as to bear against the formwork joint 23 when the second cell 3 is placed on the interconnecting plate 8. Optionally, the sealing strips 25 can cover the entire surface of the blocking section 23d of the formwork joint 23.

[0161] The thickness of each sealing strip 25 can be on the order of a hundred microns, in order to allow the passage of the airflow between the sealing strip 25 and the fuel face 10 of an interconnector 7 placed on the first cell 3.

[0162] Stack 1

[0163] An insulating junction plate 17 comprising a peripheral border 17a and a central window is fixed to the air face 9 of the plate 8. The junction plate 17 can for example be made of vermiculite.

[0164] The peripheral edge 17a of the junction plate 17 is positioned on the interconnection plate 8 so as to align the central window with the cell 3. It is also fixed to the air face 9 of the interconnection plate 8 so as to extend away from this face 9. The junction plate 17 thus forms a spacer that keeps two adjacent interconnection plates 8 apart. The peripheral edge 17a can be monolithic or comprise several sections joined end to end.

[0165] For example, the peripheral edge 17a can be fixed to the peripheral joint 20 of the interconnecting plate 8. This configuration makes it possible to obtain a stacking layer 2 in which the lights 13 have an optimized passage cross-section compared with conventional stacking layers, in which the supply lights 13 are generally masked by combs (solid parts which partially cover the lights 13).

[0166] In one embodiment, pads 18 can be fixed to the air and fuel faces of the interconnecting plate 8, along the four edges, between the supply ports 13 and the corresponding contact layer 15, 16. These pads 18 are configured to facilitate spacing between two adjacent interconnecting plates 8 in the stack 1. They can be made of the same material as the seals 20-25, i.e., glass or glass-ceramic. In this embodiment, the junction plate 17 can, for example, include fixing tabs 17b extending from the peripheral edge 17a, configured to bear against the pads 18. The number of fixing tabs 17b is then equal to the number of pads 18. The fixing tabs 17b extend above the supply ports 13, between the peripheral edge 17a and the pads 18.The number of feed pins 17b and their width are chosen so as not to penalize the flow of gas exiting or entering the ports 13.

[0167] Securing the junction plate 17 to the studs 18 makes the junction plate 17 more rigid. The junction plate 17 is in fact made of a more fragile material than the interconnection plate 8.

[0168] In another embodiment, shims can be fixed to the air and fuel faces of the interconnecting plate 8, along all four edges, between the supply ports 13 and the corresponding contact layer. These shims can, for example, be formed of a glass deposit (similar to the studs 18) and an insulating layer (made of a material similar to the junction plate 17). The height of each shim is then substantially equal to the height of the peripheral seal 20. The shims thus prevent the interconnecting plates 8 from being pinched during packaging by maintaining a rigid support capable of accommodating the movement of the interconnecting plates 8 during the melting of the seal material.

[0169] In a stack 1, each face of the interconnection plate 8 then includes studs 18 having the same thickness as the peripheral seals: the junction plate 17 is therefore sandwiched between the studs 18 and the peripheral seal 20 of the air face 9 of an interconnection plate 8 i and between the studs 18 and the peripheral seal 20 of the fuel face 10 of an immediately adjacent interconnection plate 8 i+1.

[0170] Stacking 1 is then obtained by superimposing several stacking layers, each stacking layer i comprising:

[0171] - an 8 i interconnection plate;

[0172] - a junction plate 17 i, fixed to the air face 9 of the interconnection plate 8 i; and

[0173] - an elementary electrochemical cell 3 i, whose anode 4 is fixed on the ceramic layer LSM 15 of the interconnecting plate 8 i.

[0174] This stacking layer i can then be assembled with a stacking layer i+1 comprising:

[0175] - an 8 i+1 interconnection plate; and

[0176] - an elementary electrochemical cell 3 i+1, whose anode 4 is fixed on the ceramic layer LSM 15 of the interconnection plate 8 i+1.

[0177] For that :

[0178] - the interconnecting plates 8 i and 8 i+1 are aligned so that the lights 13 O?, the lights 13 H? and the slots 14 extend one above the other;

[0179] - the cathode 5 of the elementary electrochemical cell 3 i is fixed to the grid 16 of the interconnection plate 8 i+1; and

[0180] - the junction plate 17 i is further fixed to the fuel face 10 of the interconnection plate 8 i+1.

[0181] We then obtain a stack 1 (or stack) comprising two stacking layers i and i+1. The number of stacking layers is of course not limiting: a stack 1 can in particular comprise n stacking layers i (n > 1) assembled between two end connection plates 8.

[0182] Stacking Operation 1

[0183] The following describes the operation of a stack-1 consisting of two stacking layers (n = 2). This is not a limitation, however; a stack-1 can have a larger number of layers, for example, ten, without changing its operation. Furthermore, to simplify the description, we will assume that the stack-1 is placed on a horizontal support, although this is not necessary in practice for the reactions to occur.

[0184] During operation, air is introduced into the stack 1 through one of the openings 13 O? (see Figure 7 as a non-limiting example). A first portion of the air flows vertically from the opening 13 O2 of the interconnecting plate 8 i to the opening 13 O2 of the interconnecting plate 8 i+1 (on the left of Figure 7). A second portion of this air enters the air circulation chamber of the interconnecting plate 8 i, which is delimited by the air face 9 of the interconnecting plate 8 i, the fuel face 10 of the interconnecting plate 8 i+1, and the formwork joints 23 of the interconnecting plate 8 i. This second portion of air thus comes to rest against the blocking section 23d of the formwork joint 23, guided by its guide sections O? 23a, and cannot pass through the cell 3 i.This second portion of air therefore rises along the formwork joint 23, then runs along the sealing strip 25, which prevents it from entering the cathode 5 of the cell 3 i, until it comes to rest against the longitudinal portion 24a of the barrier joint 24. The lateral portions 24b of the barrier joint 24 and the guide sections 0? 23a of the formwork joint 23 prevent the air from leaving the air supply chamber by guiding the air towards the longitudinal portion 23d. The second portion of air is therefore forced to pass through the slot 14 formed in the interconnecting plate 8 i+1, which is located above the sealing strip 25 of the interconnecting plate 8 i, and opens into the area extending between the sub-cell seal 21 of the interconnecting plate 8 i+1 and the LSM ceramic layer 15 of the interconnecting plate 8 i+1.It is therefore forced, by the formwork joint 23, to enter the anode 4 of cell 3 i+1, where the oxidation reaction takes place to produce oxygen. It should be noted here that, since cell 3 i+1 is fixed to the sub-cell joint 21 of the interconnecting plate 8 i+1, the air enters directly into the anode 4 of cell 3 i+1. The outgoing flow from the anode 4 of the cell 3 i+1, which includes the oxygen produced, then flows to the opposite sub-cell joint 21 of the interconnecting plate 8 i+1, where it is blocked and forced down towards the interconnecting plate 8 i by passing through the second slot 14 of the interconnecting plate 8 i+1, in order to join the area delimited by the fuel face 10 of the interconnecting plate 8 i+1, the air face 9 of the interconnecting plate 8 i, and the formwork joint 23 of the interconnecting plate 8 i.It is then guided by the cross sections 0? 23a of the formwork joint 23 towards the opposite light 13 0?, where it joins the flows including oxygen from the adjacent layers of stack 1.

[0185] Simultaneously, a gaseous mixture comprising water vapor and dihydrogen H₂ is introduced into stack 1 through one of the ports 13 H₂ (see Figure 6). A first portion of the gaseous mixture flows vertically from port 13 H₂ of interconnecting plate 8i to port 13 H₂ of interconnecting plate 8i+1. A second portion of the gaseous mixture enters the steam supply chamber of interconnecting plate 8i, which is delimited by the air face 9 of interconnecting plate 8i, the fuel face 10 of interconnecting plate 8i+1, and the formwork joints 23 of interconnecting plate 8i. In particular, the second portion of the gaseous mixture is guided by the cross-sections H₂ 23b of the formwork joints 23, which are arranged on either side of the light 13 H?, in the direction of the grid 16 of the interconnection plate 8 i+1.With layer 15 surrounded by the sub-cell seal 21, the second portion of the gas mixture bypasses the grid 16 and is forced into the cathode 5 of cell 3i, where the reduction reaction takes place to produce hydrogen. The outflow from the cathode 5 of cell 3i, which includes the hydrogen produced, is then guided by the opposite cross-sections H? of the formwork seal 23 of the interconnecting plate 8i to the opposite lumen 13 H?, where it joins the flows containing hydrogen from the adjacent reactors of stack 1.

[0186] Thus, the joints 20-25 form guidance and gas supply channels (air / gas mixture, oxygen, hydrogen), without participating in the mechanical structure of the stack 1, which makes it possible to eliminate welding steps and thus improve the conformity of the stack layers.

[0187] Manufacturing process

[0188] An example of a manufacturing process for a stack 1 will now be described. During a step S1, an interconnecting plate 8 i comprising the feed lights 13 and the slots 14 is produced, for example by laser cutting or stamping.

[0189] A grid 16 is fixed on the fuel face 10 and a ceramic layer LSM 15 is formed on the air face 9. The fixing and formation of these contact layers being conventional, it will not be detailed here.

[0190] During an S2 step, the peripheral seal 20 and, where applicable, studs 18, are formed on the air face 9.

[0191] In one embodiment, the peripheral seal 20 is obtained by depositing glass slurry onto the air face 9 using a syringe or nozzle to produce one or more glass beads. The interconnector 7 is then heat-treated at a temperature above its operating temperature (more precisely, the stack temperature), typically in a range between 800°C and 900°C, to obtain a glass-ceramic seal.

[0192] As an alternative to syringe-deposited slurry beads, peripheral seals 20 can be obtained by depositing pre-cut glass strips produced by casting from slurry or by depositing solid glass seals produced by melting or sintering. The shape, thickness, and profile of the peripheral seal 20 can therefore be modified at will to adapt to the geometries of the channels and stack components. Glass deposition, and in particular glass slurry bead(s), offers the advantage of allowing the creation of an infinite number of geometries.

[0193] The studs 18 can be made in a similar way to the peripheral joint 20. Preferably, the studs 18 and the peripheral joint 20 are obtained by the same process, and made of the same material.

[0194] Furthermore, the sub-cell seal 21, the sealing beads 22, and the formwork joints 23 are formed on the air face 9 of the interconnecting plate 8. The order in which these three seals are formed is irrelevant. For example, the sub-cell seal 21 can be formed first, then the sealing beads 22, and finally the formwork joints 23. These three seals 21, 22, and 23 can also be monolithic and made in a single piece, as long as the formwork joints 23 have a thickness greater than the sub-cell seal 21 and the sealing beads 22.

[0195] Here again, these different joints 21-23 can be made in a manner analogous to the peripheral joint 20.

[0196] Of course, the deposits of vitreous material to obtain the different joints in step S2 can be carried out in a different order.

[0197] It should be noted that, once the geometries and thicknesses of the material deposits to form the different joints are controlled, the interconnector plate 8 7 being monolithic, and therefore flat and not deformed by welds, the material deposits (glass in particular), which is done robotically, become a simple operation to implement in a reproducible manner and at a lower cost.

[0198] During an S3 step, cell 3 i is placed on the LSM 15 ceramic layer of the interconnecting plate 8 i. Cell 3 i is in particular positioned on the sub-cell joint 21 so that its perimeter comes to rest against the formwork joints 23.

[0199] During an S4 step, the sealing strips 25 and the barrier seals 24 are fixed to the cell 3 and the fuel face 10 of the interconnection plate 8.

[0200] More specifically, the longitudinal portion of the barrier joints 24 is fixed to the cathode 5 of the cell 3 i and its transverse portions 24b, 24c are fixed to the cross sections H? and O? 23a, 23b and where applicable the angled portion 23c of the formwork joints 23. Furthermore, the sealing strips 25 are fixed to the cathode 5 of the cell 3 i, between the longitudinal portion 24a and the transverse portions 24b of the barrier joints 24.

[0201] The sealing strips 25 can be obtained in particular by casting a glass-ceramic material in strip form. They can be pre-glued onto the first cell 3, before its placement at step S5 on the interconnection plate 8 i, or deposited onto the first cell 3 after its mounting on the interconnection plate 8 i.

[0202] During a step S5, a junction plate 17 is placed on the peripheral joint 20 and the studs 18 of the interconnection plate 8 i, so as to obtain the stacking layer i.

[0203] This results in a stacking layer 2.

[0204] It should be noted that, in an alternative embodiment, the peripheral joint 20 and the studs 18 can be made on the junction plate 17 rather than on the interconnection plate 8 in step S3. This is made possible in particular by the fact that the interconnection plate 8 is monolithic and flat, which improves the control of the material deposition.

[0205] A stacking 1 can be obtained by assembling two stacking layers i and i+1. For this, steps S1 to S5 are repeated with an interconnecting plate 8 i+1, a cell 3 i+1 and a junction plate 17 i+1. Then, during a step S10, the stacking layer i is placed on the stacking layer i+1, by positioning the junction plate 17 of the stacking layer i on the peripheral joint 20 and the studs 18 of the fuel face 10 of the interconnecting plate 8 i+1.

[0206] If necessary, steps S1 to S5 can be implemented in parallel for layers i and i+1. Thus, the interconnecting plates 8 i and i+1 can first be made (step S1), then the joints 20-25 can be formed on the interconnecting plates 8 i and i+1 (steps S2 to S4), etc. and finally the interconnecting plates 8 i and i+1 can be assembled with the joining plates 17.

[0207] In practice, steps S1 to S5 can be repeated as many times as necessary to obtain a stacking 1 comprising a larger number of stacking layers.

[0208] Once stack 1 is assembled, electrical connection plates, also called end plates, can be placed on the junction plates of the end layers of stack 1. Several conventional solutions exist for completing the stack, including a closing cover at the top and an interface plate at the bottom for connecting the stack to its power supply. Seals and contact layers are installed, as well as, where applicable, junction plates. The end plates can touch the entire surface of the upper and lower end interconnectors. Thick end plates (10 to 20 mm) provide rigid ends that allow the interconnector stack to be compressed.

[0209] The presence of the junction plates 17 and the studs 18 protects the stacking layers 2 and prevents damage to them. They also limit pinching during compression, which could lead to obstruction of the passage areas (lights 13 and / or slots 14) for the gases supplying the cells 3 and electrical contact.

[0210] During an S6 step, the different stacking layers 2 are compressed between the terminal connecting plates to ensure good electrical continuity of the contact planes between the interconnecting plates 8, and a heat treatment is carried out to fuse the glassy material of the different seals 20-24, strips 25 and studs 18 and fix together the interconnecting plate 8, the cell 3 and the junction plate 17 of each stacking layer 2 by means of the seals 20-25.

[0211] It should be noted that by proceeding according to the steps described above, all operations are carried out on the air face 9, with the exception of the installation of the grid 16 and, optionally, the peripheral seal 20 on the fuel face 10. Alternatively, the vitreous material of the peripheral seal 20 on the fuel face 10 can be applied to the associated junction plate 17, thus avoiding the need to turn over the interconnection plate 8 during the manufacturing process. Simplifying the handling of components offers a clear advantage for series production on an assembly line.

[0212] From a fluidic perspective, the circulations in stack 1, obtained according to the process described above, are equivalent to those in conventional architectures (cross-flow feed). However, a significant gain is observed in terms of the gas passage cross-section on the steam side, thus limiting the pressure losses in this circuit. The steam flows directly from port 13H to grid 16 and then to the opposite port 13H, which reduces the pressure losses in stack 1. The pressure losses in the air circuit induced by the layer changes in stack 2 (a longer, indirect path for the air) are inconsequential since, during operation, the objective of an electrolyzer is to produce hydrogen ions.

Claims

DEMANDS 1. Electrical and fluidic interconnector (8, 20-23) for a reactor for the electrolysis of water or carbon dioxide CO₂ at high temperature, for the co-electrolysis of water also at high temperature with carbon dioxide CO₂, or for a solid oxide fuel cell comprising: - a monolithic interconnection plate (8, 8 i, 8 i+1)), the interconnection plate (8) having a first face (9), a second face (10) opposite the first face (9), the first face (9) and the second face (10) being connected by a border comprising two first opposite edges and two second opposite edges, at least one through-feed light (13) being formed in the interconnection plate (8) near each edge and at least two through-feed slots (14) being formed in the interconnection plate (8) near the two second edges, the feed lights (13) and the slots (14) opening into the first and second faces (9, 10) of the interconnection plate (8); - a first contact layer (15), fixed on the first face (9) and configured to come into surface contact with a first electrode (4) of a first elementary electrochemical cell (3); - a second contact layer (16), fixed on the second face (10) and configured to come into surface contact with a second electrode (5) of a second elementary electrochemical cell (3); a first of the supply lights (13) being configured to receive a first gas, a second of the supply lights (13) being in fluidic communication with the first of the supply lights (13) via the first contact layer (15) and being configured to receive the first gas, a third of the supply lights (13) being configured to receive a second gas, and a fourth of the supply lights (13) being in fluidic communication with the third of the supply lights (13) via the second contact layer (16) and being configured to receive the second gas; and - seals (20-23) fixed on the first face (9), so that the interconnecting plate (8), the supply lights (13), the slots (14) and the seals (20-23) together delimit first and second gas circulation compartments.

2. Electrical and fluidic interconnector according to claim 1, in which the seals (20-23) are made of at least one of the following materials: glass, glass-ceramic.

3. Electrical and fluidic interconnector according to any one of claims 1 and 2, wherein the seals (20-23) each comprise at least one peripheral seal (20) fixed on the first face (9) and the second face (10) of the interconnection plate (8), respectively, so as to continuously surround the first contact layer (15) and the second contact layer (16), respectively.

4. Electrical and fluidic interconnector according to claim 3, wherein the seals (20-23) further comprise a sub-cell seal (21) fixed continuously along the periphery of the first contact layer (15), the sub-cell seal (21) being disposed on the first face (9) between the slots (14) and the peripheral seal (20) and being configured to bear against the first electrode (4) of the first elementary electrochemical cell (3).

5. Electrical and fluidic interconnector according to claim 4, wherein the sub-cell seal (21) comprises two first sides parallel to the slots (14) and two second sides perpendicular to the slots (14), and the seals (20-23) further comprising two sealing cords (22) fixed each along one of the second sides of the sub-cell seal (21) by connecting the two first sides of the sub-cell seal (21).

6. Electrical and fluidic interconnector according to any one of claims 4 and 5, wherein each supply light (13) comprises two opposite end edges, the joints (20-23) further comprising formwork joints (23) extending from the sub-cell joint (21) to a respective end edge, the formwork joints (23) connected to the end edges of the adjacent supply lights (13) being able to further connect to each other along the sub-cell joint (21) and have a thickness at least equal to a sum of a thickness of the sub-cell joint (21) and a thickness of the first elementary electrochemical cell (3).

7. Electrical and fluidic interconnector according to claim 6, wherein the formwork joints (23) extending on either side of a supply light (13) located near a second edge (12) are further connected to each other and have a thickness at least equal to a sum of the thickness of the sub-cell joint (21) and of a thickness of the first elementary electrochemical cell (3) such that each formwork joint (23) is configured to come abutting against an edge of the first elementary electrochemical cell (3) when the second electrode (5) of the first elementary electronic cell (3) is in surface contact against the second contact layer (16) of an additional interconnecting plate.

8. Electrical and fluidic interconnector according to any one of claims 1 to 7, further comprising additional seals (24, 25) fixed at least partially to the second electrode (5) of the elementary electrochemical cell (3), the additional seals comprising two barrier seals (24) each comprising: - a first portion (24a) extending continuously along a second associated edge to the power supply lights (13) which are adjacent to the first edges (11) of the interconnecting plate (8); and - two second portions (24b) each extending continuously between the first portion (24a) and the supply light (13) which is adjacent to the second edge (12), the first portion (24a) of the barrier joints (24) being positioned on the cell (3) so that a slot is located between the first portion (24b) and the associated second edge (12).

9. Electrical and fluidic interconnector according to claim 8 taken in combination with one of claims 6 and 7, wherein each barrier joint (24) is further fixed on all or part of the formwork joints (23).

10. Electrical and fluidic interconnector according to any one of claims 8 and 9, wherein the additional seals further comprise two sealing strips (25) configured to be fixed each on the second electrode (5) of the first elementary electrochemical cell (3) so as to extend along the first portion (24a) of a respective barrier seal (24), between the two second portions (24b) of the barrier seal (24), the sealing strips (25) being made of a non-porous gas material.

11. Stacking (1) comprising a stacking layer (2) comprising: - an electrical and fluidic interconnector (8 i) according to any one of claims 1 to 10; and - an elementary electrochemical cell (3) comprising a first electrode (4), an electrolyte (6) and a second electrode (5), the first electrode (4) of the cell (3) elementary electrochemical being in contact with the first contact layer (15) and the joints (21-23) of the electrical and fluidic interconnector.

12. Stack (1) according to claim 11, further comprising an additional electrical and fluidic interconnector (8 i+1) according to any one of claims 1 to 10, the second electrode (5) of the elementary electrochemical cell (3) being in contact with the second contact layer (16) of the additional electrical and fluidic interconnector by means of additional seals (23, 24, 25).

13. Stack (1) according to any one of claims 11 and 12, further comprising an additional elementary electrochemical cell (3) comprising a first electrode (4), an electrolyte (6) and a second electrode (5), the first electrode (4) of the additional elementary electrochemical cell (3) being in contact with the first contact layer (15) of the additional electrical and fluidic interconnector (8 i+1) by means of additional seals (21, 22, 23).

14. Stacking (1) according to any one of claims 12 and 13, wherein the additional joints (21, 22, 23) comprise a sub-cell joint (21) according to any one of claims 4 and 5, sealing cords (22) according to claim 5 and / or formwork joints (23) according to claim 6.

15. Stack (1) according to any one of claims 11 to 14, further comprising a junction plate (17) made of an electrically insulating material, the junction plate comprising a peripheral rim (17a) fixed on at least a part of the joints (20-23) extending away from the first face (9) of the interconnection plate (8 i).

16. Stack (1) according to claim 15, further comprising studs (18) fixed on the first face (9) of the interconnecting plate (8 i) being adjacent to an associated power light (13), the junction plate (17) comprising as many tabs (17b) as studs (18), each tab (17b) being fixed on a respective stud (18) partially masking the associated power light (13).

17. A method for manufacturing a stack (1) according to any one of claims 11 to 16, comprising the following steps: - formation of a stacking layer according to the following substeps: - supply (S1) of an interconnecting plate (8 i) having the first and second faces (9, 10), the power lights (13), the slots (14) and the first and second contact layers (15, 16); - deposition (S2) of a vitreous material on the first face (9) of the interconnection plate (8 i); - placement (S3) of the elementary electrochemical cell (3) against the first contact layer (15) so that the first electrode (4) comes into contact with the vitreous material; and - heat treatment (S6) of the stacking layer (2) formed of the interconnecting plate (8), the glassy material and the elementary electrochemical cell (3) so as to transform the glassy material into joints (20-23) and to fix the elementary electrochemical cell (3) on the interconnecting plate (8 i).

18. Method for manufacturing a stack (1) claim 17, further comprising, prior to the heat treatment step (S6), an additional step (S4) of depositing a glassy material on the elementary electrochemical cell (3) so as to form additional joints (24, 25).

19. Method of manufacturing a stack (1) according to any one of claims 17 and 18, further comprising placing (S5) a junction plate (17) on the glassy material, around the elementary electrochemical cell (3) and at a distance from the first face (9) of the interconnection plate (8), prior to the heat treatment step (S6).

20. A method for manufacturing a stack (1) according to claim 19, further comprising, prior to the heat treatment step (S6), the following steps: - formation of an additional stacking layer comprising an additional interconnecting plate (8 i+1) and an additional elementary electrochemical cell (3); and - placement of the second face (10) of the additional interconnection plate (8 i+1) of the additional stacking layer on the junction plate (17).

Images