High-temperature electrolysis or co-electrolysis (SOEC) reactor comprising a stack of electrochemical cells and a container housing the stack and filled with a material forming a gas-tight barrier, associated production method.

Abstract

High temperature electrolysis or co-electrolysis (SOEC) reactor comprising a stack of electrochemical cells and a container housing the stack and filled with a material forming a gas-tight barrier, associated production method. The invention essentially consists in integrating into a container (6) at least one electrochemical stack of solid oxide electrochemical cells (1), intended to operate at high temperature as an electrolysis or co-electrolysis reactor, with a volume between them which is filled with a material including at least one glassy matrix which will act as a second gas-tight barrier, i.e. as a barrier additional to those of the seals around the cathode and anodic compartments of the stack. Figure for the abstract: fig.2

Description

Title of the invention: High-temperature electrolysis or co-electrolysis (SOEC) reactor comprising a stack of electrochemical cells and a container housing the stack and filled with a material forming a gas-tight barrier, Associated production method. Technical field

[0001] The present invention relates to the field of solid oxide fuel cells (SOFC, English acronym for "Solid Oxide Fuel Cell"), that of high temperature water electrolysis (EHT, or EVHT for high temperature water vapor electrolysis, or HTE English acronym for High Temperature Electrolysis, or HTSE English acronym for High Temperature Steam Electrolysis) also with solid oxides (SOEC, English acronym for "Solid Oxide Electrolyser Cell"), and that of high temperature co-electrolysis of water and another gas chosen from carbon dioxide CO2. nitrogen dioxide NO2.

[0002] The invention relates more particularly to the production of an electrochemical device constituting a high-temperature water electrolysis or co-electrolysis (HTE) reactor of the SOEC type, and where appropriate operating in reversible mode in a SOFC type fuel cell, with a stack of elementary electrochemical cells.

[0003] The present invention aims firstly to make the operation of a hydrogen production system using one or more electrochemical devices more reliable and secure, by managing gas leaks likely to escape from the stack.

[0004] Although described with reference mainly to the application of high temperature water electrolysis, the invention applies equally well to co-electrolysis of water and another gas chosen from carbon dioxide CO2, as to a SOFC fuel cell. Prior art

[0005] A SOFC fuel cell or an EHT electrolyser is an electrochemical device consisting of a stack of elementary patterns each comprising a solid oxide electrochemical cell, consisting of three layers superimposed on each other anode / electrolyte / cathode, and interconnection plates made of metal alloys also called bipolar plates, or interconnectors. The function of the interconnectors is to ensure both the passage of the electric current and the circulation gases in the vicinity of each cell (injected water vapor, hydrogen and oxygen produced in an EHT electrolyzer; injected air and hydrogen and water produced in an SOFC stack) and to separate the anode and cathode compartments which are the gas circulation compartments on the anode and cathode sides of the cells respectively.

[0006] To carry out the electrolysis of water vapor at high temperature EHT, typically between 600 and 950°C, water vapor H2O is injected into the cathode compartment. Under the effect of the current applied to the cell, the dissociation of water molecules in vapor form is carried out at the interface between the hydrogen electrode (cathode) and the electrolyte: this dissociation produces dihydrogen gas H2 and oxygen ions. The dihydrogen is collected and evacuated at the outlet of the hydrogen compartment. The oxygen ions O2- migrate through the electrolyte and recombine into dioxygen at the interface between the electrolyte and the oxygen electrode (anode).

[0007] To ensure the operation of a SOFC fuel cell, air (oxygen) is injected into the cathode compartment and hydrogen into the anode compartment. The hydrogen H2 will transform into H+ ions and release electrons which are captured by the anode. The H+ ions arrive at the cathode where they combine with O2- ions formed from the oxygen in the air, to form water. The transfer of H+ ions and electrons to the cathode will produce a direct electric current from the hydrogen.

[0008] To increase the flow rates of hydrogen and oxygen produced in the case of EHT electrolysis or to increase the electrical power supplied in the case of an SOFC fuel cell, it is known to stack several elementary electrochemical cells on top of each other by separating them by the interconnectors. The assembly is positioned between two end connection plates, usually called terminal plates, one and / or the other of which supports the electrical power supplies and the gas supply / collection of an electrolyzer (electrolysis reactor) or of an SOFC fuel cell.

[0009] Furthermore, to improve the quality of the electrical contacts established between the interconnectors and the electrodes, and therefore the performance of the aforementioned electrochemical devices, electrical contact elements are individually intercalated and arranged on the electrodes. In an electrochemical device, a nickel grid is conventionally used for contact with the hydrogen electrode (cathode in an EHT reactor, anode in an SOFC cell), because it gives satisfactory results at low cost.

[0010] All of these constituents form a stack which can be assembled mechanically and which is usually referred to by the English term “stack”.

[0011] In a stack, it is necessary to ensure good sealing at each interconnector, between anode and cathode compartments. This sealing depends the design of the seals and the materials used for the various components in relation to them, but also the gas pressure acting on the seal and the level of tightening of the stack.

[0012] Given the high operating temperature ranges of EHT electrolysers and SOFC fuel cells, typically 600°C to 1000°C, the seals or gaskets are conventionally made from glass or glass-ceramic. A glass seal is in a pasty state at the operating temperature.

[0013] The multi-material nature, the geometric complexity and the thermomechanical constraints applied to this structure (stack) which works at high temperature impose enormous constraints for the production and maintenance of these seals.

[0014] In practice, it is found that existing EHT stacks, by their design, have relatively high residual leak rates, compared to the very low leak rates theoretically achievable with vitroceramic seals.

[0015] Their operation accommodates this provided that certain limits are not exceeded, generally set at around 1% of the H2 / H20 feed flow rate.

[0016] That being said, even with lower leak rates, observed in a standard manner in operation, in a range estimated between 0.05 to 0.1% of the flow rate, the quantity of gas released by these external leaks can become significant for high-power stacks in which large flow rates circulate.

[0017] In current industrial concepts of high-power electrolyzer systems, a system comprises a set of modules, each module comprising an independent heating enclosure, commonly called a "hot box", containing several stacks aligned next to each other. The heating enclosure is swept by a constant air flow, which makes it possible to dilute the hydrogen releases due to leaks from the stacks. This precaution is taken with regard to the risk of localized accumulation of hydrogen pockets, but this type of operation has the disadvantage of being costly in terms of energy. The release of hydrogen in the enclosure under air flow, which self-ignites at high temperature, can also, if the leak is sufficiently localized, form a gas jet which causes a defect of the emerging crack type, and lead to the formation of a sustained flame and to localized heating on the external walls of the stacks.

[0018] Such hot spots can have significant short-term consequences on the integrity of a stack.

[0019] Beyond the simple overall reduction of the gas leak rate through the stacks by improving the sealing of its structure, the management of leaks which generally appear following the formation of cracks is a technical problem to be overcome to make the operation and safety of high-temperature hydrogen production systems more reliable.

[0020] There is therefore a need to further improve electrochemical devices with em stacks each forming an SOEC type electrolysis reactor, operating where appropriate in reversible mode in an SOFC type fuel cell, in particular by reducing the release to the outside of gas leaks from the stacks without this harming the electrochemical operation of the devices.

[0021] The aim of the invention is to meet at least part of this need. Statement of the invention

[0022] To do this, the invention firstly relates to an electrochemical device, constituting an SOEC electrolysis or co-electrolysis reactor, intended to operate at high temperature, and where appropriate a SOFC fuel cell in reversible mode comprising:

[0023] - at least one electrochemical stack comprising:

[0024] a plurality of electrochemical cells based on solid oxides of the SOEC / SOFC type;

[0025] a plurality of electrical and fluidic interconnectors, each consisting of at least one component made of electronically conductive and gas-tight material for supplying or collecting the electrical current to the cells and for supplying, collecting and circulating gases on each electrode of each electrochemical cell; the interconnectors being arranged individually on either side of each of the electrochemical cells;

[0026] a plurality of sealing gaskets each arranged between two adjacent interconnectors, around each gas inlet / outlet, to form a first gas-tight barrier;

[0027] two plates called terminal plates between which the plurality of electrochemical cells, interconnectors and joints are arranged;

[0028] - a container arranged around the electrochemical stack and housing the latter in delimiting a volume filled at least partially with at least one material suitable for forming a second gas-tight barrier against gases likely to escape from the stack during operation at high temperature, the envelope being further arranged to allow compression of the stack during operation at high temperature.

[0029] According to an advantageous construction variant, the container is made up of at least one peripheral wall and a bottom wall integral with or made integrally with the peripheral wall and against which one of the two end plates of the stack bears directly or indirectly, and the device comprises a means for distributing the compression force, arranged opposite the bottom wall, bearing directly or indirectly against the other of the two end plates of the stack to apply the compression clamping.

[0030] According to a first variant, the material is a glassy matrix whose glass transition temperature is less than or equal to the high operating temperature of the stack, the glassy matrix filling at least the part of the volume around the plurality of cells, interconnectors and seals.

[0031] Preferably, the vitreous matrix further covers at least the periphery of the end plate opposite that against the bottom wall, and where appropriate the force distribution means.

[0032] According to a second variant, the materials are a mineral powder filling at least the part of the volume around the plurality of interconnector cells and seals and a vitreous matrix whose glass transition temperature is less than or equal to the high operating temperature of the module, the vitreous matrix surmounting the mineral powder. The mineral powder may be composed of one or more vermiculite or talc type minerals of small particle size. Preferably, the particle size is less than 20 μm, more preferably between 5 and 10 μm. The advantage of this variant with two filling materials (mineral powder surmounted by a vitreous matrix) is to facilitate the removal of the stack and to allow possible reuse of the container.In fact, a layer of thin vitreous matrix can be deposited, which is easier to destroy and since the stack does not adhere to the mineral powder, it is easier to extract it from the container for removal.

[0033] Preferably, the vitreous matrix in its initial state is based on glass frit. Once at high temperature, the frit melts to form a bath of molten glass. Once cooled, the vitreous matrix sets and forms a solid and compact block which constitutes the filling material of the container.

[0034] According to a first advantageous embodiment, the bottom wall of the container being provided with through openings forming the passages for the supply and outlet gases of the stack and the electrical supply connections and, where appropriate, for measuring the electrical voltage at each interconnector, the container further housing, between the bottom wall and the lower end plate of the stack, a support frame and a set of seals supported by the frame and ensuring sealing around the passages for the supply and outlet gases of the stack and the electrical supply connections.

[0035] Advantageously, the support frame and the set of seals form a single-piece sealing part, independent and housed in the container or pre-assembled with the stack, before the latter is housed in the container.

[0036] Advantageously, gas supply and outlet tubes are assembled with the bottom wall opposite its passages, forming a gas supply and outlet manifold.

[0037] In this first mode, rods forming the electrical power supply connections and, where appropriate, wires, preferably rigid, for measuring electrical voltage are preferably integrated into the stack and pass through the bottom wall of the container.

[0038] In an advantageous configuration where each interconnector is made up of three thin flat sheets, pierced with holes and elongated along two mutually orthogonal axes of symmetry, the flat sheets being laminated and assembled together by welding, an electrical voltage measuring wire is connected, in particular by welding, to the central sheet.

[0039] In this first mode, the force distribution means may be a block bearing directly against the upper end plate of the stack and preferably incorporated into the glass matrix.

[0040] Advantageously, the block is in the form of a plate with a surface area enlarged relative to that of the stack so as to increase the path traveled in the vitreous matrix by gas leaks likely to escape from the stack when operating at high temperature.

[0041] Advantageously, the lower edge of the widened plate, preferably incorporated in the glass matrix, has a truncated cone-shaped surface which widens from the upper end plate of the stack, so as to avoid the formation of pockets of gas resulting from leaks.

[0042] Advantageously also, the lateral edge of the enlarged plate, preferably incorporated in the vitreous matrix, is a wall which extends towards the interior of the vitreous matrix, so as to contain towards the interior the gas leaks likely to escape from the stack during operation at high temperature.

[0043] To make the device even more secure, several variant embodiments can be provided to deal with gas leaks likely to escape from the stack during operation at high temperature.

[0044] According to a first variant, the enlarged plate is pierced at its periphery with one or more through holes, the device comprising:

[0045] - a cover tightly fixed to the container and / or to the enlarged plate in the form of a dice limiting with the latter a volume (VI) in fluid communication with the hole(s) emerging from the enlarged plate, the cover being pierced, preferably in its center, with a passage,

[0046] - a tube for supplying a gas called inerting gas, assembled with the cover in regarding its passage by forming a collector for supplying inerting gas to the volume (VI) in which gas leaks likely to escape from the stack during operation at high temperature arrive through the through hole(s).

[0047] By "inerting gas" is meant here and within the framework of the invention, a gas which will reduce or even eliminate the risks linked to gas leaks likely to escape of the stack.

[0048] The volume of inerting gas is advantageously controlled and monitored. In the event of hydrogen leakage from the stack, two options are possible for the choice of inerting gas to supply volume VI:

[0049] - either a gas containing oxygen in which the escaping hydrogen will self-ignite on the surface of the glass as mentioned above,

[0050] - either an inert gas into which hydrogen can be released (mixed) without risk of ignition subject to implementing oxygen level monitoring and potentially gas renewal / purging, due to concomitant leaks of hydrogen and air from the stack.

[0051] In other words, this first variant consists of installing a sealed volume V1 supplied with gas from the outside which will treat in said volume the gas leaks from the stack.

[0052] According to a second variant, the enlarged plate is pierced at its periphery with one or more through holes, the device comprising:

[0053] - a cover tightly fixed to the container and / or to the enlarged plate in limiting with the latter a volume (V2) in fluid communication with the hole(s) emerging from the enlarged plate, the cover being pierced, preferably in its center, with a passage,

[0054] - a recovery tube assembled with the cover opposite its passage in forming a gas recovery collector for gas leaks likely to escape from the stack during operation at high temperature which are recovered through the through hole(s).

[0055] In other words, this second variant consists of installing a sealed volume V2 which will collect gas leaks from the stack to evacuate them to the outside.

[0056] Advantageously, the through hole(s) is / are closed by a filter.

[0057] For fixing, the cover(s) is / are advantageously fixed to the container and / or to the enlarged plate by means of a plurality of bolts with the interposition of at least one sealing gasket between them. This gasket is preferably a flat or toric shaped gasket or a glass-metal type connection suitable for ensuring sealing at the high operating temperature of the stack.

[0058] According to a second embodiment, the bottom wall of the container is solid, the device further comprising a cover plate arranged above the stack, preferably being incorporated in the glassy matrix, the cover plate being provided with through openings forming the passages for the supply and outlet gases of the stack and the electrical supply connections and, where appropriate, electrical voltage measurement at each interconnector, the cover plate further forming a force distribution means.

[0059] In this second mode, gas supply and outlet tubes are preferably assembled with the cover plate opposite its passages, forming a gas supply and outlet manifold.

[0060] In this second mode also, the device comprises as another means of force distribution, a rod in ball joint connection with the cover plate to achieve the clamping by compression.

[0061] The interconnectors of the stack and / or the container may each be made of a single or several metal pieces, preferably of ferritic steel with approximately 20% chromium, preferably of CROFER® 22APU or F18TNb, or of nickel base of the Inconel® 600 or Haynes 230® type or of stainless steel of the 310S type.

[0062] According to an advantageous configuration, the general shape of the stack and of the container is preferably axisymmetric. It is also possible to envisage a general oval, square or rectangular shape.

[0063] Thus, the invention essentially consists of integrating into a container at least one electrochemical stack with solid oxide electrochemical cells, intended to operate at high temperature as an electrolysis or co-electrolysis reactor, with a volume between them which is filled with a material including at least one glassy matrix which will act as a second gas-tight barrier, that is to say as a barrier additional to those of the seals around the cathode and anodic compartments of the stack.

[0064] The formulation of the glass of the material guarantees in the temperature range a non-devitrified glassy matrix, that is to say one which does not crystallize, remaining viscous. The glassy matrix which therefore coats at least the lateral edges of the stack is viscous at the high operating temperatures of the electrochemical stack.

[0065] In the event of a leak in the stack, the gases which escape from it bubble into the matrix which has become viscous, and the stack is thus protected from any risk of hot spots created by the self-ignition of hydrogen on the lateral edges of the stack.

[0066] In other words, locally, if a gas jet forms following the appearance of a crack opening into the stack, the bubbling in the viscous matrix will allow the gases to be released onto the free surface of this matrix.

[0067] The consequences of a hydrogen leak are thus limited. Indeed, the gas leak and the resulting hot spot, the temperature of which can reach more than 1000°C, is of no consequence when it is created in the glassy matrix.

[0068] The viscous matrix, by forming a second sealing barrier around the external walls of the electrochemical stack and by delaying the diffusion of the gas, also contributes to the reduction of the overall mass leakage rate of the stack.

[0069] As indicated above, instead of a single filling material consisting of a vitreous matrix, the volume between the stack and the container can be filled with a powder of one or more mineral materials of a layer of vitreous matrix.

[0070] The mineral powder allows the evacuation of gases likely to come from leaks in the stack, by forming the second sealing barrier in which self-ignition of hydrogen cannot occur. After diffusion in the mineral layer, the gases are released onto the free surface of the glassy matrix in a viscous state.

[0071] Another advantage of the invention is to promote thermal exchanges with the exterior since the thermal exchanges are made by conduction from the stack passing through the filling material and through the container instead of natural convection with the surrounding air according to the state of the art. Thermal regulation of the electrochemical device is thus facilitated.

[0072] Another advantage of the invention is to use a filling material with electrical insulation properties

[0073] The invention benefits all high-temperature industrial hydrogen production systems in which the management and reduction of hydrogen leaks are major problems.

[0074] The invention also relates to a method for producing an electrochemical device as described above, comprising the following steps:

[0075] a / housing the electrochemical stack with support against the bottom wall of the container, where appropriate with interposition of the support frame and the set of seals supported by the frame;

[0076] b / placing the force distributor means above the stack so as to apply the clamping force by compressing the stack;

[0077] c / filling with the material(s) including at least the glassy matrix in the liquid state of the volume between the stack and the container at least up to the upper end plate, preferably with incorporation of the force distribution means. Other advantages and characteristics will become more apparent upon reading the detailed description, given for illustrative and non-limiting purposes, with reference to the following figures. Brief description of the drawings

[0078] [Fig-1] [Fig.l] is a schematic cross-sectional view of an example of electrochemical device with a stack of solid oxide electrochemical cells according to the state of the art.

[0079] [Fig.2] [Fig.2] is a schematic cross-sectional view of an example of electrochemical device with a stack of solid oxide electrochemical cells according to the invention.

[0080] [Fig.3], [Fig.3A], [Fig.3B] Figures 3, 3A, 3B are schematic views respec tively in perspective and in cross-section along two cutting axes of a container according to a first embodiment of an electrochemical device according to the invention.

[0081] [Fig.4], [Fig.4A] Figures 4 and 4A are schematic views respectively in exploded and top view of a container according to figures 3 to 3B in the bottom wall of which a single-piece sealing part is mounted.

[0082] [Fig.5], [Fig.5A], [Fig.5B], [Fig.5C] Figures 5, 5A, 5B, 5C are schematic views respectively in perspective and in cross-section and detail of an electrochemical stack according to the first embodiment of an electrochemical device according to the invention.

[0083] [Fig.6], [Fig.6A] Figures 6 and 6A are schematic views respectively of top and detail of an interconnector of the stack with its connection to an electrical voltage measuring wire.

[0084] [Fig.7] [Fig.7] is an exploded view showing an advantageous arrangement of the wires measuring the electrical voltage of three adjacent interconnectors within an electrochemical stack of a device according to the invention.

[0085] [Fig.8A], [Fig.8B], [Fig.8C] Figures 8A, 8B, 8C are schematic views res respectively in perspective and in cross-section showing the steps of producing an electrochemical device according to the first embodiment of the invention.

[0086] [Fig.9], [Fig.9A] Figures 9 and 9A are schematic views respectively in perspective and cross-section of an electrochemical device according to a second embodiment according to the invention.

[0087] [Fig. 10] [Fig. 10] repeats [Fig.9] showing a variant of filling by two materials of the volume between container and stack of an electrochemical device according to the invention.

[0088] [Fig. 11] [Fig. 11] is a cross-sectional view of a device according to a first variant embodiment of the invention.

[0089] [Fig. 12] [Fig. 12] is an exploded view of the device of [Fig. 11].

[0090] [Fig.l3A], [Fig.l3B] Figures 13A and 13B are partial sectional views of detail of a device according to Figures 11 and 12, according to two distinct alternatives.

[0091] [Fig. 14], [Fig.14A] Figures 14 and 14A are schematic sectional views partial and detailed view of a device according to figures 11 and 12, with an improvement in the evacuation of gases.

[0092] [Fig. 15] [Fig. 15] is a cross-sectional view of a device according to a second variant embodiment of the invention.

[0093] [Fig. 16], [Fig.16A] Figures 16 and 14A are schematic views in partial section and in detail of a device according to [Fig. 15], with an improvement in the evacuation of gases.

[0094] [Fig.l7A], [Fig.l7B] Figures 17A and 17B are partial sectional views of a detail of a device according to the invention, according to two distinct alternatives for producing sealing at the cover. Detailed description

[0095] For the sake of clarity, the same elements of an electrochemical device according to the state of the art and of an electrochemical device according to the invention are designated by the same numerical references.

[0096] In the illustrated examples, the electrochemical devices 1 have a general axisymmetric shape around a central axis X.

[0097] The symbols and arrows for water vapor H2O supply, distribution and recovery of dihydrogen H2 are shown for clarity and precision, to illustrate the operation of an electrochemical device operating as a high temperature electrolysis reactor.

[0098] Throughout the present application, the terms “lower”, “upper”, “above”, “below”, “inner”, “outer”, “internal” “external” are to be understood with reference to an electrochemical device according to the invention in operating configuration, i.e. with its electrochemical stack vertical.

[0099] It is also specified that the electrochemical stack described is of the solid oxide type (SOEC, acronym for "Solid Oxide Electrolyte Cell") operating at high temperature. Thus, all the constituents (anode / electrolyte / cathode) of an electrolysis cell are ceramics. The high operating temperature of an electrolyzer (electrolysis reactor) which can operate in reversible mode in a SOFC fuel cell (acronym for "Solid Oxide Fuel Cell") is typically between 600°C and 1000°C.

[0100] Typically, the characteristics of a SOEC electrolysis cell suitable for the invention, of the cathode support type (CSC), may be those indicated as follows in Table 1 below.

[0101] [Tables 1] Electrolysis cell Unit Value Cathode Constituent material Ni-YSZ Thickness pm 400 Thermal conductivity W m1K 1 13.1 Electrical conductivity Q 1 m1 105 Porosity 0.37 Permeability m2 1013 Tortuosity 4 Current density A.m2 5300 Anode Constituent material LSM , LSC Thickness pm between 10 and 50 Thermal conductivity W m1K 1 9.6 Electrical conductivity Q 1 m1 1 104 Porosity 0.37 Permeability m2 1013 Tortuosity 4 Current density A.m2 2000 Electrolyte Constituent material YSZ Thickness pm <10 Resistivity Q m 0.42

[0102] [Fig.l] shows an electrochemical device 1 according to the state of the art.

[0103] Such a device 1 comprising an electrochemical stack 2 with electro cells 20 chemicals, based on solid oxides of the SOEC / SOFC type which can operate reversibly in a high-temperature electrolyzer or SOFC fuel cell.

[0104] Within the stack, a plurality of electrical and fluidic interconnectors 21 are arranged individually on either side of each of the electrochemical cells. Each interconnector consists of at least one component made of electronically conductive and gas-tight material for bringing or collecting the current. electrical to the cells and to bring, collect and circulate gases on each electrode of each electrochemical cell.

[0105] Finally, within the stack 2, a plurality of contact elements and sealing joints 22 around each gas inlet / outlet is arranged individually on each electrode of electrochemical cells.

[0106] At the ends of the stack 2, two end plates 3, 4 are arranged. The lower end plate 4 is provided with through openings 40, 41 forming the passages for the supply and outlet gases of the stack 2 so as to produce an electrical and fluidic connector for bringing or collecting the electric current from the electrochemical device to the outside and for bringing, collecting and circulating the gases from the electrochemical device to the outside. As shown in this [Fig.l], the through openings 40, 41 are respectively dedicated to the supply of water vapor and the recovery of the hydrogen produced. Other through openings not shown are dedicated to the supply of draining gas (air, oxygen), to the recovery of the oxygen O2 produced, and to the supply of the electric current.

[0107] A means for distributing the compression force 5, in the form of a support block, is arranged on the upper end plate 3 to apply a force for clamping the stack 2 by compression. For mounting this block 5, a guide and centering part 50 can be interposed between the upper plate 3 and the block. This part 50 guarantees the centering and blocking of the support block 5.

[0108] In such a device 1 according to the state of the art, the stack 2 is in the open air. As shown in [Fig.l], even with very good quality seals 22, following the appearance of a through crack, there remains a risk of gas leaks into the open air, in particular of the hydrogen produced, which can therefore self-ignite on contact with the open air and create hot spots on the external lateral edges of the stack 2. A hot spot can cause serious irreversible damage to the external lateral edges of the stack 2.

[0109] To eliminate this risk, the inventors thought of housing the stack in a container 6 and coating it, that is to say filling the volume between stack 2 and container 6 with a glassy matrix 7 whose glass transition temperature is less than or equal to the high operating temperature of stack 2. Thus this matrix 7 is viscous at the high operating temperature of stack 2, forming a sealing barrier to gases likely to escape from the latter.

[0110] A first embodiment of such a device 1 with container 6 and glass matrix 7 is shown in 2 to 5C.

[0111] The container 6 consists of a wall of at least one peripheral wall 60 arranged around the stack 2 and a bottom wall 61 integral or made integrally with the peripheral wall 60. Preferably, as shown in detail in Figures 3 to 3B, the container 6 is a single-piece metal part.

[0112] The walls 60 and 61 of the container may be made of steel, preferably ferritic steel with approximately 20% chromium, preferably CROFER® 22APU or F18TNb, or nickel-based steel of the Inconel® 600 or Haynes 230® type or 310S stainless steel. Other materials may be considered. Generally speaking, the material of the container must be compatible, essentially in terms of corrosion, with operation at high temperature.

[0113] The bottom wall 61 is provided with through openings 62, 63 forming the passages for the supply and outlet gases of the stack 2. Advantageously, gas supply and outlet tubes 64, 65 are assembled with the bottom wall 61 opposite its passages 62, 63, forming a gas supply and outlet collector.

[0114] Furthermore, the bottom wall 61 is provided with through openings 66 to allow the passage of the electrical power supply and electrical voltage measurement connections respectively to each interconnector 21 of the stack 2.

[0115] The lower end plate 4 of the stack 2 bears indirectly against the bottom wall 61.

[0116] Indeed, as shown in Figures 4 and 4A, a single-piece sealing part 8 is interposed between the lower end plate 4 of the stack 2 and the bottom wall 61. This single-piece sealing part 8 can be pre-assembled with the stack 2 or mounted against the bottom wall 61 of the container 6 before housing the stack 2.

[0117] This single-piece sealing part 8 consists of a support frame 80 and a set of seals 81 supported by the frame 80. The set of seals 81 is located around through openings 82, 83 in the frame which ensure sealing respectively around the passages for the supply and outlet gases of the stack and the electrical supply connections. In addition, the frame 80 may comprise through openings 83 for the passage of electrical voltage measurement wires to each interconnector. Each of these through openings 82, 83 of this single-piece sealing part 8 is therefore opposite respectively one of the corresponding through openings 62, 63, 66 of the bottom wall 61 of the container 6.

[0118] Furthermore, the device 1 comprises a block 5 for distributing compression force, arranged opposite the bottom wall, bearing directly against the upper end plate of the stack 2 to apply a compression clamping of the latter.

[0119] Thus, as symbolized in [Fig.2], surrounded by the glassy matrix 7 contained between the container 6 and the stack 2, the latter is protected from any risk of hot spots created by the self-ignition of hydrogen on these external lateral edges.

[0120] Indeed, in the event of a leak from the stack 2 in operation at high temperature, the gases which escape from it come to oil in some way in the vitreous matrix 7 which is in a viscous state. Locally, if a jet of gas forms following the appearance of a through crack in the stack 2, the bubbling produced in the matrix 7 will allow the gases to be released onto the free surface of the glass, that is to say at a distance from the stack.

[0121] The consequences of a hydrogen leak are thus limited, the leak and the resulting hot spot whose temperature can reach more than 1000°C is of no consequence because it is created on the free surface of the matrix 7, unlike a device 1 according to the state of the art, as shown in [Fig.l] where a hot spot can cause serious irreversible damage to the lateral edges of the stack 2 in the open air.

[0122] Figures 5 to 5C show a variant of simplification of the interface between a stack 2 and the bottom wall 61 of the container 6. In this variant, the stack 2 integrates the connections 24 to the current leads and 25 to the voltage measurements made individually on each interconnector 21, which are arranged and fixed inside the structure of the stack 2, in passages which are respectively dedicated to them from through openings 42, 43 in the lower end plate 4L. The passages 200, 201 within the stack, respectively for supplying gas and for recovering produced gas, are free of any object.

[0123] The integration in the stack 2 of the connections 25, in the form of wires, of voltage measurements makes it possible to protect them and limits the stresses on these wires during phase changes (solid / glassy) of the glass. The voltage measurement wires are preferably nickel wires with a diameter not exceeding 0.5 mm.

[0124] Figures 6 and 6A show an advantageous integration in the case of an interconnector 21 with three thin flat sheets 210, 211, 212, which are pierced with holes and elongated along two mutually orthogonal axes of symmetry, the flat sheets being laminated and assembled together by welding. To better understand the production of the interconnectors 21 with three thin sheets, reference may advantageously be made to patent application FR3040061A1.

[0125] The thin sheets are preferably made of steel, more preferably of ferritic steel with approximately 20% chromium, preferably of CROFER® 22APU or F18TNb.

[0126] An electrical voltage measuring wire 25 is directly welded to a protruding tab 213 of the central sheet 211 which opens into a through opening 214 opposite the dedicated opening 43 of the relatively fragile lower terminal plate 4, which are pointed at the middle plate of the interconnectors.

[0127] As shown in [Fig.7], to facilitate mounting at each stage of the stack 2, an interconnector 21.2 of a given stage is mounted by being oriented 180° by relative to an interconnector 21.1 of an adjacent stage, so that the legs 213 have an opposite position from one stage to the other and thus alternate the position of the voltage measuring wires 25.

[0128] A good spacing of these measuring wires 25 between the interconnectors is guaranteed. In other words, the risk of two measuring wires 25 being too close to each other is avoided, which could distort the individual electrical voltage measurements interconnector by interconnector of the stack, and create a parasitic electrical contact between two interconnectors.

[0129] A method of assembling an electrochemical device 1 according to the first embodiment of the invention is now described with reference to FIGS. 8A to 8C.

[0130] Step a / : the electrochemical stack 2 is housed with support against the bottom wall 61 of the container 6, with the interposition of the single-piece sealing part 8 consisting of the support frame 80 and the set of seals 81 supported by the frame ([Fig.8A]). In the variant of a stack 2 which integrates the electrical connections 24 and the electrical voltage measuring wires 25, care is taken to ensure that these pass through the openings 66 of the bottom wall 6 provided for this purpose.

[0131] Step b / : The force distributor block 5 is put in place by guiding and centering it on the upper end plate 3 above the stack so as to apply the clamping force by compression of the stack 2 ([Fig.8B]).

[0132] Step c / : the volume between the stack 2 and the container 6 is then filled with the glass matrix 7 based on glass frit in its initial state, at least up to the upper end plate 3 ([Fig.8C]). Preferably, the force distribution block 5 is incorporated into the glass matrix 7.

[0133] The frit may be a powder of crushed glass in its initial state. When it is heated, once past the melting point, lower than the operating temperature of the stack 2, this frit liquefies and transforms into a viscous paste which forms a gangue around the stack 2. When the glass cools and returns below its glass transition temperature, it solidifies and forms a solid block.

[0134] Prior to step a / , the thermomechanical conditioning of the stack 2 is carried out.

[0135] To do this, a thermomechanical treatment is applied to the stack produced so as to finalize at least the installation of electrical contact elements and sealing joints within the stack. This thermomechanical treatment may also include the reduction of the electrochemical cells.

[0136] The temperatures are determined by the temperatures necessary for the installation of the seals, typically made of glass or glass-ceramic, for example between 850 and 950°C for a duration adapted according to the type / geometry of sealing and the glass. The temperature increase can be done for a given module up to a value allowing the formation of thermal gradients to be avoided

[0137] The reduction of electrochemical cells can be done from 650°C or advantageously at 800°C for a period of one hour to several days depending on the hydrogen flow rates sent.

[0138] When the solid block 7 is formed, the high temperature operation of the device 1 can take place for the production of hydrogen.

[0139] When the temperature rises, the glass frit constituting the matrix 7 is then transformed into a viscous fluid which covers the lateral edges of the stack 2 and preferably covers the upper end plate 3. This fluid, as long as it is maintained at a temperature above the glass transition temperature, has a viscosity ensuring the coating of the stack 2 without transmitting mechanical stresses to it, in particular linked to the differential expansions of the materials.

[0140] During cooling of the device 1, when the matrix 7, which has not devitrified when hot, becomes solid again, the formation of cracks within the matrix remains without consequence, the glass not having in this operational phase a sealing function to ensure, because at these cooling temperatures, no gas passes through the stack.

[0141] When the device 1 is reheated for a new operating cycle, as soon as the matrix 7 becomes viscous again, it then regains its fluidic properties and can once again perform its role as a gas-tight barrier.

[0142] A second embodiment of an electrochemical device 1 according to the invention is shown in Figures 9 and 9A.

[0143] The bottom wall 61 of the container 6 and the end plate 4 of the stack 2 are solid here.

[0144] A cover plate 9 is arranged above the upper end plate 3 of the stack 2, preferably being incorporated into the glass matrix 7.

[0145] The cover plate is provided with through openings 90, 91, 92 respectively forming the passages for the supply and outlet gases of the stack and the electrical supply connections 24 and the electrical voltage measurement wires 25 to each interconnector.

[0146] These passages 90, 91, 92 are opposite the corresponding passages 30, 31, of the upper end plate 3 of the stack 2.

[0147] This cover plate 9 further forms a force distribution means on which a rod 10 preferably rests in a ball joint connection as another force distribution means to achieve the compression clamping of the stack 2.

[0148] Gas supply and outlet tubes 93, 94 are advantageously assembled with the cover plate 9 opposite its passages 90, 91 forming a gas supply and outlet manifold.

[0149] Thus, in the assembly according to this second mode, the container is simplified and only has a container function to ensure, the gas collector function being ensured by the covering part 9.

[0150] For mounting the stack 2 in the container 6, a guide and centering part 11 can be installed on the bottom wall 61.

[0151] As illustrated in [Fig.10], instead of a filling material consisting solely of a vitreous matrix 7, the volume between stack 2 and container 6 can be filled with a layer of powder of mineral materials 70, for example of the vermiculite or talc type of low granularity, preferably compacted, covered with a layer of vitreous matrix 71.

[0152] The layer of mineral powder 70 allows the evacuation of gases likely to escape from the stack 2, by forming a second sealing barrier in which self-ignition of the hydrogen cannot occur. The gases then come after diffusion in the mineral layer 70 to be released onto the free surface of the layer of vitreous matrix 71. This variant makes it easier to remove a stack 2 and to allow possible reuse of the container 6. Indeed, it is possible to dimension a layer of vitreous matrix 70 sufficiently thin so that when it is cold it can be easily destroyed to easily dismantle the stack 2 from the container 6, because in fact the stack is not adherent to the mineral powder 70.

[0153] Although illustrated in [Fig. 10], in relation to the second embodiment, this variant with two superimposed layers, respectively of mineral powder 70 and of vitreous matrix 71 can be implemented in a device according to the first embodiment.

[0154] In the event of gas leakage from the stack which may escape through the glass matrix, additional safety measures may be provided, in particular by installing volumes for treatment or collection and evacuation of these gas leaks.

[0155] A first variant embodiment of a device is shown in Figures 11 to 14A.

[0156] The device 1 as a whole according to this first variant is shown in Figures 11 and 12.

[0157] According to this variant, the support block 5 is in the form of a plate with a surface area enlarged relative to that of the stack, so as to increase the path traveled in the vitreous matrix by gas leaks likely to escape from the stack when operating at high temperature.

[0158] The geometry of this enlarged plate makes it possible to slow down the leaks emitted by stack 2 and bubbling in the glass matrix 7 by increasing the length of the leak path. The greater the difference in diameter between the enlarged plate 5 and stack 2, the greater the distance to be traveled in the glass for gas leaks.

[0159] This enlarged plate 5 is pierced at its periphery with one or more through holes 53. These holes 53 are of small diameter to protect against the risk of accumulation of gases. In addition, the diameter of these holes 53, preferably distributed regularly around the periphery of the plate 5, is small, typically of the order of a millimeter, so that the glass of the matrix 7, the viscosity of which is very high compared to that of the gases, cannot rise by capillary action.

[0160] A cover 12 is fixed in a sealed manner to the container 6, delimiting with the latter a volume (VI) in fluid communication with the through holes 53, the cover being pierced, preferably in its center, with a passage.

[0161] A tube 13 for supplying a gas called inerting gas, assembled with the cover opposite its passage, forming a collector for supplying inerting gas to the volume (VI) in which gas leaks likely to escape from the stack during operation at high temperature arrive through the through holes.

[0162] As illustrated 13B, the lower edge 51 of the widened plate 5, incorporated in the vitreous matrix, has a frustoconical surface which widens from the upper end plate 3 of the stack, so as to avoid the formation of pockets of gas resulting from leaks, as symbolized in [Fig.l3A] in the case of a horizontal lower edge 51.

[0163] As illustrated in Figures 14 and 14A, the lateral edge of the enlarged plate, preferably incorporated in the glass matrix 7, is a wall 52 or blade which extends towards the inside of the glass matrix, so as to contain towards the inside the gas leaks likely to escape from the stack in operation at high temperature. In other words, this wall or blade 52 plunging into the glass matrix 7 forms a baffle which makes it possible to channel the leaks coming from the stack 2 towards the cover 12.

[0164] Thus, according to this first variant, the cover 12 is installed to form a sealed enclosure delimiting a volume V1 in its upper part into which an inerting gas is brought, the stack 2 being immersed in the lower part of the enclosure, in the vitreous matrix 7.

[0165] The inerting gas is either an oxygen-containing gas in which the hydrogen leaks from the stack 2 can self-ignite on the surface of the glass of the matrix 7, or an inert gas in which the hydrogen leaks can mix without risk of ignition. Preferably, in the latter case, monitoring of the oxygen level and potentially renewal / gas sweeping, because concomitant leaks of hydrogen and air from the stack are possible. Generally speaking, monitoring of the inerting gas (pressure / temperature, hydrogen level) is an indirect method that allows quantification or at least detection of possible leaks from the stack to the outside. The appearance of a leak will in fact generate an overpressure of the cover gas informing of the appearance of a gas leak from stack 2.

[0166] Thus, in the event of gas leaks from the stack, the escaping gases bubble into the vitreous glass of the matrix 7. The longer the time required for the gas to pass through this second sealing barrier 7, the lower the leak rate. The addition of the cover 12 to the stack makes it possible to increase the distance of glass to be crossed by a leak that would bubble into the vitreous matrix.

[0167] Whatever the inerting gas solution chosen, the main function of the glass matrix of providing a second barrier and protecting the external walls of the stack in the event of a localized hydrogen leak is therefore retained.

[0168] A second alternative safety embodiment of a device 1 is shown in Figures 15 to 16A.

[0169] Here, a cover 16 pierced in its center with a passage, is fixed in a sealed manner to the enlarged plate 5 by delimiting with the latter a volume V2 in fluid communication with the through holes 53.

[0170] A recovery tube 17 is assembled with the cover 16 opposite its passage, forming a collector for recovering gas leaks likely to escape from the stack during operation at high temperature, which are recovered through the holes 53.

[0171] Here, the collection of the escaping gases is therefore carried out by forming a cavity closed to the volume V2, above the stack 2. This volume V2 can be subjected to a slight depression. Just as for the first variant, the diameter of the holes 53 is small, typically so that the glass of the matrix 7 cannot rise by capillary effect.

[0172] The small diameter holes 53 can be enlarged by being individually closed by a filter. This can be a standard filter, such as that marketed in the form of a disc under the name PORAL®

[0173] As with the first variant, the lower edge 51 of the widened plate 5 is preferably a truncated cone shape which widens outwards to avoid gas pockets. Also to best confine leaks and direct them towards the holes, the edge of the widened wall comprises a vertical wall or blade 52.

[0174] Finally, an additional cover 12, like that of the first variant, pierced to allow the gas evacuation tube 13 to pass through, can be fixed above, in particular directly to the container 6, and preferably in a sealed manner.

[0175] As shown in Figures 17A and 17B, the cover 12 is advantageously fixed to the container 6 in their peripheral parts in the form of flanges, by means of a plurality of bolts 14 preferably distributed regularly around the flanges.

[0176] To ensure the seal between them, a seal 15 is interposed between them, in particular in an annular groove provided for this purpose in the container 6. The seal 15 can be a flat-shaped ([Fig.l7A]) or toric ([Fig.l7B]) seal or a glass-metal type connection adapted to ensure the seal at the high operating temperature of the stack. The prerequisites in terms of sealing on the interface between cover 12 and container 6, subjected to a very low pressure gradient, can remain modest. The pressure and the supply of the cover gas are controlled with a supply which can, if necessary, continuously compensate for any leakage. With a judicious choice of seals and mechanical assembly, the mechanical forces to be applied to the assembly to ensure the seal at the interfaces can be reduced.

[0177] The widened plate 5 may be mounted integrally or not with the end plate 3 via a mechanical connection blocking the relative vertical movements of the two parts. A part 50 guaranteeing the centered position of the centering pin type cover is however required to block the relative horizontal movements between the two parts.

[0178] The invention is not limited to the examples which have just been described; it is possible in particular to combine characteristics of the examples illustrated within non-illustrated variants.

[0179] Other variants and improvements may be envisaged without departing from the scope of the invention.

[0180] If in all the examples illustrated, the shapes of stack and container forming an electrochemical device are axisymmetric around a central axis, it is possible to envisage implementing the invention on other shapes, such as stacks and containers of square or rectangular section. In general, the invention can be implemented for any stack geometry, because the container has the sole function of being a stack container and the material forming the gas-tight barrier. Such a container therefore remains subject to low thermomechanical constraints and its geometry can easily adapt to that of the stacks.

[0181] As illustrated, the integration of electrical connections and electrical voltage measurement wires in a stack or in a cover plate simplifies its integration in a container. That being said, other embodiments are possible: in fact, the glassy matrix having properties of an electrical insulator, more conventional assemblies, with current leads made by connected current rods on the periphery of the stack end plates and voltage measuring wires connected in the corners of the interconnectors are possible.

Claims

Claims

1. Electrochemical device (1), constituting an electrolysis or co-electrolysis SOEC reactor, intended to operate at high temperature, and where appropriate an SOFC fuel cell in reversible mode comprising: - at least one electrochemical stack (2) comprising: a plurality of electrochemical cells (20) based on solid oxides of the SOEC / SOFC type; a plurality of electrical and fluidic interconnectors (21), each consisting of at least one component made of electronically conductive and gas-tight material for supplying or collecting the electrical current to the cells and for supplying, collecting and circulating gases on each electrode of each electrochemical cell; the interconnectors being arranged individually on either side of each of the electrochemical cells; a plurality of sealing gaskets (22) each arranged between two adjacent interconnectors, around each gas inlet / outlet, to form a first gas-tight barrier; two plates called end plates (3,4) between which the plurality of electrochemical cells, interconnectors and seals are arranged; - a container (6), arranged around the electrochemical stack and housing the latter by delimiting a volume filled at least partially with at least one material (7; 70, 71) adapted to form a second sealing barrier against gases likely to escape from the stack during operation at high temperature, the envelope being further arranged to allow compression of the stack during operation at high temperature.

2. Electrochemical device according to claim 1, the container consisting of at least one peripheral wall (60) and a bottom wall (61) integral with or made integrally with the peripheral wall and against which one of the two end plates of the stack bears directly or indirectly, the device comprising a means for distributing compression force (5), arranged opposite the wall bottom, resting directly or indirectly against the other of the two end plates of the stack to apply the compression clamp.

3. An electrochemical device according to claim 2, the material being a glassy matrix whose glass transition temperature is less than or equal to the high operating temperature of the stack, the glassy matrix filling at least the portion of the volume around the plurality of cells, interconnectors and seals.

4. Electrochemical device according to claim 3, the vitreous matrix further covering at least the periphery of the terminal plate opposite that against the bottom wall, and where appropriate the force distribution means.

5. An electrochemical device according to claim 2, the materials being a mineral powder (70) filling at least the portion of the volume around the plurality of cells, interconnectors and seals and a glassy matrix (71) having a glass transition temperature less than or equal to the high operating temperature of the module, the glassy matrix overlying the mineral powder.

6. Electrochemical device according to one of claims 3 to 5, the glass matrix being in its initial state, based on glass frit.

7. Electrochemical device according to one of claims 2 to 6, the bottom wall of the container being provided with through openings (62, 63, 66) forming the passages for the supply and outlet gases of the stack and the electrical supply connections and, where appropriate, for measuring the electrical voltage at each interconnector, the container further housing, between the bottom wall and the lower end plate of the stack, a support frame (80) and a set (81) of seals supported by the frame and ensuring sealing around the passages for the supply and outlet gases of the stack and the electrical supply connections.

8. Electrochemical device according to claim 7, the support frame and the set of seals forming a single-piece sealing part (8), independent and housed in the container or pre-assembled with the stack, before housing the latter in the container.

9. Electrochemical device according to claim 7 or 8, gas supply and outlet tubes (64, 65) being assembled with the wall bottom opposite its passages by forming a gas supply and outlet collector.

10. Electrochemical device according to one of claims 7 to 9, rods (24) forming the electrical power supply connections and where appropriate wires (25), preferably rigid, for measuring electrical voltage being integrated into the stack and passing through the bottom wall of the container.

11. Electrochemical device according to claim 10, each interconnector being made up of three thin flat sheets (210, 211, 212), pierced with holes and elongated along two mutually orthogonal axes of symmetry, the flat sheets being laminated and assembled together by welding, an electrical voltage measuring wire being connected, in particular by welding, to the central sheet.

12. Electrochemical device according to one of claims 7 to 11, the force distribution means being a block (5) bearing directly against the upper end plate of the stack and preferably incorporated in the glass matrix.

13. Electrochemical device according to claim 12, the block being in the form of a plate with a surface area enlarged relative to that of the stack so as to increase the path traveled in the glassy matrix by gas leaks likely to escape from the stack when operating at high temperature.

14. An electrochemical device according to claim 13, the lower edge (51) of the widened plate, preferably incorporated in the glassy matrix, having a frustoconical surface which widens from the upper end plate of the stack, so as to avoid the formation of gas pockets from leaks.

15. An electrochemical device according to claim 13 or 14, the lateral edge of the enlarged plate, preferably incorporated in the glassy matrix, being a wall (52) which extends towards the interior of the glassy matrix, so as to contain towards the interior any gas leaks likely to escape from the stack during operation at high temperature.

16. Electrochemical device according to one of claims 12 to 15, the enlarged plate being pierced at its periphery with one or more through holes (53), the device comprising: - a cover (12) fixed in a sealed manner to the container and / or to the enlarged plate, delimiting with the latter a volume (VI) in fluid communication with the through hole(s) of the plate enlarged, the cover being pierced, preferably in its center, with a passage, - a tube (13) for supplying a gas called inerting gas, assembled with the cover opposite its passage forming a collector for supplying inerting gas to the volume (VI) in which gas leaks likely to escape from the stack in operation at high temperature arrive through the through hole(s).

17. Electrochemical device according to one of claims 12 to 15, the enlarged plate being pierced at its periphery with one or more through holes (53), the device comprising: - a cover (16) fixed in a sealed manner to the container and / or to the enlarged plate, delimiting with the latter a volume (V2) in fluid communication with the through hole(s) of the enlarged plate, the cover being pierced, preferably in its center, with a passage, - a recovery tube (17) assembled with the cover opposite its passage, forming a collector for recovering gas leaks of gas likely to escape from the stack in operation at high temperature which are recovered by the through hole(s).

18. Electrochemical device according to claim 17, the through hole(s) being closed by a filter.

19. Electrochemical device according to one of claims 12 to 18, the cover(s) being fixed to the container and / or to the enlarged plate by means of a plurality of bolts (14) with the interposition of at least one sealing gasket (15) between them.

20. Electrochemical device according to one of claims 12 to 19, the seal (15) being a flat or toric shaped seal or a glass-metal type connection suitable for guaranteeing sealing at the high operating temperature of the stack.

21. Electrochemical device according to one of claims 2 to 6, the bottom wall of the container being solid, the device further comprising a cover plate (9) arranged above the stack, preferably being incorporated in the glassy matrix, the cover plate being provided with through openings (90, 91, 92) forming the passages for the supply and outlet gases of the stack and the electrical supply connections and, where appropriate, electrical voltage measurement at each interconnector, the cover plate further forming a force distribution means.

22. Electrochemical device according to claim 21, gas supply and outlet tubes (93, 94) being assembled with the cover plate opposite its passages, forming a gas supply and outlet manifold.

23. Electrochemical device according to claim 21 or 22, comprising as another force distribution means, a rod (10) in ball joint connection with the cover plate to achieve the compression clamping.

24. Method for producing an electrochemical device according to one of claims 2 to 23, comprising the following steps: a / housing the electrochemical stack with support against the bottom wall of the container, where appropriate with interposition of the support frame and the set of seals supported by the frame; b / placing the force distributor means above the stack so as to apply the clamping force by compression of the stack; c / filling with the material(s) including at least the vitreous matrix in the liquid state of the volume between the stack and the container at least up to the upper end plate, preferably with incorporation of the force distributor means.

Images