Solid oxide electrochemical reactor with optimised manifold base

Abstract

The invention relates to a manifold base (2) for a solid oxide electrochemical reactor, wherein the base is formed from an assembly of layers of material (9) stacked in a sealed manner along a stacking direction, and: - at least one of these layers of material (9) comprises a longitudinal groove passing through the thickness of the layer of material (9), and forming a longitudinal flow duct that is substantially perpendicular to the stacking direction; - at least one of these layers of material (9) comprises a transverse port forming a transverse duct through the thickness of the layer of material (9), wherein this transverse duct extends substantially along the stacking direction and is arranged facing the longitudinal flow duct.

Description

[0001] DESCRIPTION

[0002] Solid oxide electrochemical reactor with optimized collector base

[0003] TECHNICAL FIELD

[0004] The invention relates to the technical field of solid oxide electrochemical reactors, and more specifically solid oxide electrolyzers (SOEC, "Solid Oxide Electrolyzer Cell") and solid oxide fuel cells (SOFC, "Solid Oxide Fuel Cell").

[0005] These electrolysers and fuel cells are electrochemical reactors of the same nature but with reverse operation, operating at high temperature, currently of the order of 600°C to 1000°C. In the case of an electrolyser, they make it possible to obtain dihydrogen and dioxygen from water (for the electrolysis of water), and in the case of a fuel cell, to provide electrical energy from dihydrogen, or another fuel, and dioxygen.

[0006] These electrochemical reactors consist of one or more stacks of electrochemical cells held tightly on a collector base to ensure electrical contacts and sealing. Each electrochemical cell has a layer of solid electrolyte sandwiched between two layers of electrodes. The solid electrolyte layer allows the transport of ions between the anodic and cathodic layers, the latter being the site of chemical reactions.

[0007] In a SOEC reactor, the water molecule is dissociated into hydrogen at the hydrogen electrode (cathode), and the O2' ions migrate through the electrolyte to recombine into oxygen at the oxygen electrode (anode). SOEC cells thus produce hydrogen by dissociating water molecules.

[0008] In a SOFC reactor, oxygen is reduced at the oxygen electrode (cathode), O2' ions migrate through the electrolyte. An oxidation reaction then takes place at the hydrogen electrode (anode) and the SOFC cells thus produce electricity and water by combining dihydrogen and dioxygen. PRIOR ART

[0009] Electrochemical reactors are generally arranged in one or more stacks of cells mounted on a collector base allowing the inlets / outlets of fluid used in the reaction.

[0010] Current arrangements for managing fluids entering and leaving cell stacks are complex and bulky, and are not very conducive to the industrialization of solid oxide electrochemical reactors.

[0011] STATEMENT OF THE INVENTION

[0012] The aim of the invention is to improve the solid oxide electrochemical reactors of the prior art.

[0013] To this end, the invention relates to a collector base for a solid oxide electrochemical reactor, comprising a support surface adapted to support said at least one stack of solid oxide electrochemical cells, and comprising inlet and outlet connections for the fluids used in the solid oxide electrochemical reactor. This collector base is formed from an assembly of layers of material superimposed in a sealed manner, in a stacking direction. In addition:

[0014] - at least one of these layers of material comprises a longitudinal groove passing through the thickness of the layer of material, and forming a longitudinal flow conduit which is substantially perpendicular to the stacking direction;

[0015] - at least one of these layers of material comprises a cross-section orifice forming a cross-section conduit in the thickness of the layer of material, this cross-section conduit extending substantially in the stacking direction and being arranged opposite said longitudinal flow conduit.

[0016] According to another object, the invention relates to a solid oxide electrochemical reactor comprising:

[0017] - at least one stack of solid oxide electrochemical cells which each comprise a layer of solid electrolyte arranged between two layers of electrodes;

[0018] - a collector base as described above. According to another object, the invention relates to a method of manufacturing a collector base as described above, comprising steps of superimposing said layers of material, in a sealed manner, in a stacking direction.

[0019] The invention allows the production of solid oxide electrochemical reactors, the construction of which is simpler compared to the prior art and the costs of which are reduced. This makes possible or is compatible with industrialization, even in large series, which is currently necessary in this technical field.

[0020] The invention makes it possible to obtain a solid oxide electrochemical reactor whose collector base integrates the fluidic functions, even complex ones, in an optimized and compact manner.

[0021] Counterintuitively in fluidics, compactness is favored over traditional measures to limit pressure losses (large radii of curvature, few changes of direction, etc.). However, the performance of fluid management is improved by the integration of different functions.

[0022] The invention also makes it possible to improve the operational safety of solid oxide electrochemical reactors by transferring the sealing problems of the conduits and connections to the collector base, the construction of which offers guaranteed sealing.

[0023] The solid oxide electrochemical reactor according to the invention can be obtained by different processes allowing this constitution in superimposed layers of material, in particular processes compatible with large-scale industrialization.

[0024] The collector base of such a solid oxide electrochemical reactor also allows for the optional integration of numerous components that are generally scattered here and there in the complex fluid circuits of prior art reactors, and thus allows for a solid oxide electrochemical reactor with numerous functions in its collector base, which further improves compactness and reduces cost. The collector base according to the invention may include the following additional features, alone or in combination:

[0025] - the support surface comprises connection orifices for connecting to the collector base said at least one stack of solid oxide electrochemical cells, each of said inlet and outlet connections being fluidically connected to one of said connection orifices by at least one longitudinal flow conduit and at least one cross conduit;

[0026] - said longitudinal groove defines the longitudinal flow duct by its side walls, and this longitudinal flow duct is further delimited by solid portions of the two adjacent layers of material;

[0027] - the cross-member orifice is superimposed on a cross-member orifice of the same contour on an adjacent layer of material, said cross-member conduit being delimited by the side walls of several cross-member orifices aligned on several adjacent layers of material;

[0028] - at least one longitudinal groove is a straight groove;

[0029] - said longitudinal groove delimits a parallelepiped hollow space;

[0030] - at least one longitudinal groove is a groove extending along at least two portions forming an angle between them, delimiting a hollow space with at least one change of direction in the plane of the corresponding layer of material;

[0031] - at least one cross-hole is a through hole of square outline;

[0032] - the width of the longitudinal groove is substantially equal to the side of the square forming the outline of the crosspiece hole;

[0033] - at least one layer of material consists of an assembly of sheets of material superimposed in a sealed manner, following the stacking direction;

[0034] - several of said sheets of material each comprise a heat exchange thickness, the heat exchange thicknesses being superimposed;

[0035] - the heat exchange thicknesses are adjacent to at least one of said cross-holes or at least one of said longitudinal grooves; - said heat exchange thicknesses are superimposed in an alternating and sealed manner, with the alternation of a heat exchange thickness for a first fluid, and a heat exchange thickness for a second fluid;

[0036] - at least one layer of material comprises a housing and a heat exchanger arranged in this housing, this housing being in fluid communication with at least one of said cross-member orifices or at least one of said longitudinal grooves;

[0037] - said housing is a through cavity formed in the thickness of the layer of material, and in that the heat exchanger is parallelepipedal;

[0038] - the heat exchanger consists of heat exchange conduits superimposed alternately;

[0039] - the collector base comprises at least one valve arranged in one of said longitudinal flow conduits or cross conduits;

[0040] - the collector base comprises at least one valve arranged between two longitudinal flow conduits formed in the same layer of material;

[0041] - said valve comprises a shutter sliding transversely to the corresponding conduit;

[0042] - the collector base comprises a housing for the closure flap in a layer of material adjacent to the layer of material which comprises the conduit adapted to be closed by said closure flap;

[0043] - said valve is actuated by a control rod which extends into a passage provided in at least one layer of material.

[0044] The method according to the invention may comprise the following additional steps, alone or in combination:

[0045] - forming said layers of material by making said longitudinal grooves and said cross-holes in layers of rigid metallic material;

[0046] - superimposing said layers of material in the stacking direction; - carrying out solid-state diffusion welding by subjecting the stack of layers of material to a predetermined clamping and a predetermined temperature.

[0047] PRESENTATION OF FIGURES

[0048] Other characteristics and advantages of the invention will emerge from the non-limiting description which follows, with reference to the appended drawings in which:

[0049] - figure 1 functionally illustrates a solid oxide electrochemical reactor according to the invention;

[0050] - Figure 2 illustrates the collector base of the solid oxide electrochemical reactor;

[0051] - figure 3 is an exploded view of the collector base;

[0052] - Figure 4 is an exploded view of one of the layers of material of the collector base;

[0053] - figure 5 illustrates a heat exchange thickness of figure 4;

[0054] - figure 6 illustrates another heat exchange thickness of figure 4;

[0055] - Figure 7 is a sectional view of one or other of the heat exchange thicknesses of Figures 5 and 6;

[0056] - Figure 8 is an exploded view of another layer of material of the collector base;

[0057] - Figure 9 is an exploded view of the heat exchanger of Figure 8;

[0058] - figure 10 is a schematic perspective view of the conduits made in the collector base;

[0059] - Figure 11 is a sectional view illustrating a valve of the manifold base;

[0060] - figure 12 illustrates another position of the valve of figure 11.

[0061] Elements similar to and common to the various embodiments have the same reference numbers in the figures. DETAILED DESCRIPTION

[0062] Figure 1 is a functional schematic view, in section, of a solid oxide electrochemical reactor according to the invention.

[0063] The solid oxide electrochemical reactor here is, for example, a solid oxide fuel cell or a solid oxide electrolyser, with an operating temperature of around 600 to 1000°C. This electrochemical reactor can also be reversible, being able to operate alternately in both modes (solid oxide electrolyser or solid oxide fuel cell).

[0064] In operation, the reactor is placed in a thermal enclosure (not shown) allowing the reactor to be brought to operating temperature and maintained there.

[0065] The reactor comprises at least one stack of solid oxide electrochemical cells 1 mounted on a collector base 2. In the present illustrative example, four stacks 1 are mounted on the collector base 2.

[0066] The stacks 1 of cells are constituted, in a known manner, of an alternating stack of electrochemical cells, generally with interconnection plates adapted to distribute the fluids in these electrochemical cells. Each electrochemical cell comprises a layer of solid electrolyte arranged between two electrode layers, and the interconnection plates are electrically conductive plates provided with channels for distributing the reaction fluids. The stacks 1 of electrochemical cells are of a known constitution in this technical field and will not be described in more detail here.

[0067] To operate, these stacks 1 need to be supplied with incoming fluids and require the collection of outgoing fluids. These fluids are, for example, depending on the operating mode of the reactor (fuel cell or electrolyzer), high-temperature water vapor, dihydrogen, dioxygen, etc.

[0068] The collector base 2 comprises a support surface 3, on which the stacks 1 are mounted. Conduits open onto this support surface 3 and are connected to the means for distributing the fluids in each stack 1, so that the collector base transports the fluids entering and leaving the stacks 1.

[0069] The collector base 2 can also participate in the clamping of the stack 1. Indeed, the stack 1 requires clamping between end plates for electrical contact to be made and for sealing elements between the layers in the stack 1 to be efficient. In this technological field of solid oxide electrochemical reactors, this clamping function is critical for the proper operation of the reactor, taking into account the constraints linked in particular to high operating temperatures.

[0070] The electrochemical reactor can here provide this clamping function thanks to the collector base 2 and an end plate 4, the stack 1 being clamped between these two elements. Figure 1 schematically illustrates two variants for providing this clamping function. From left to right in Figure 1:

[0071] - the first stack 1 comprises an external clamping element 5 (shown schematically in the figure as a press element, adapted to exert a force on the stack 1) i

[0072] - on the second, third, and fourth stack 1, tie rods 6 (produced for example by threaded rods screwed into a first layer of material of the collector base 2), pass through the end plate 4, and the tightening is implemented and calibrated by nuts 7.

[0073] The collector base 2 has a construction in layers of material 9 which is suitable for implementing any type of clamping function of the stacks 1, thanks to clamping means which can be fixed on the layer of material 9 which comprises the support surface 3.

[0074] The collector base 2 is thus formed from an assembly of layers of material 9 which are each constituted by a plate of rigid material. The layers of material 9 are superimposed in a sealed manner in a stacking direction (the vertical direction in the example of figure 1).

[0075] The layers of material 9 are shown diagrammatically in Figure 1 by dotted lines delimiting, in this sectional view, the junctions 10 between each layer of material. The sectional view of Figure 1 is a schematic view, and not an actual section, because it illustrates all the supply and collection conduits, and the other fluidic elements, on the same plane. In practice, the invention allows an advantageous arrangement of these elements in three dimensions in the collector base 2, as explained below.

[0076] In this example, for illustrative purposes, the electrochemical reactor is a solid oxide fuel cell, supplied with fuel and fresh air, producing electrical energy, and producing as output a fuel-depleted stream and an oxygen-depleted air stream as a result of the reaction taking place in stack 1.

[0077] In this example of an electrochemical reactor which is a solid oxide fuel cell, the collector base 2 therefore comprises:

[0078] - a fuel supply conduit 11;

[0079] - a fresh air supply duct 12;

[0080] - a depleted fuel collection conduit 13, through which the fluid resulting from the consumption of part of the fuel is evacuated;

[0081] - a depleted air collection duct 14, through which the air is evacuated after consumption of part of its oxygen.

[0082] Alternatively, in the case where the electrochemical reactor is in solid oxide electrolysis mode, conduit 11 is a steam supply, conduit 12 is an air supply, conduit 13 is a hydrogen outlet (with residual steam), conduit 14 is an air and oxygen outlet.

[0083] Each of these conduits 11, 12, 13, 14 allows the supply and collection of the corresponding fluid, for all of the stacks 1 which are mounted on the collector base 2. In practice, the reactor comprises at least one stack 1 and the conduits 11, 12, 13, 14 will be sized to correspond to the number of stacks 1 to be supplied.

[0084] These conduits 11, 12, 13, 14 can open onto any face of the collector base 2 thanks to the layered arrangement. In addition, the conduits 11, 12, 13, 14 can also open, optionally, onto connectors 15 allowing, for example, several collector bases 2 to be mounted in series or in parallel.

[0085] Figure 1 illustrates an example of a complex arrangement incorporating several functions detailed below, for each stack 1 .

[0086] The fuel supply conduit 11 comprises two conduits connecting it to the fuel inlet of the stack 1:

[0087] - a direct conduit 16 connecting it via a valve 17;

[0088] - an exchanger conduit 18 connecting it via a heat exchanger 19, which makes it possible to establish a heat exchange between the fuel inlet and the fuel outlet.

[0089] Controlling valve 17 makes it possible to control the quantity of fuel passing through heat exchanger 19 before it enters stack 1.

[0090] The fresh air supply duct 12 comprises two ducts connecting it to the air inlet of the stack 1:

[0091] - a direct conduit 20 connecting it via a valve 21;

[0092] - an exchanger duct 22 connecting it via a heat exchanger 23, which makes it possible to establish a heat exchange between the air inlet and the air outlet.

[0093] Controlling the valve 21 makes it possible to control the quantity of air passing through the heat exchanger 23 before it enters the stack 1.

[0094] The depleted fuel collection conduit 13 comprises an exchanger conduit 24 connecting it to the fuel outlet of the stack 1, via the heat exchanger 19 and a valve 25.

[0095] The depleted air collection duct 14 comprises an exchanger duct 26 connecting it to the depleted air outlet of the stack 1, via the heat exchanger 23 and a valve 27.

[0096] The control of the valves 17, 21, 25, 27 makes it possible to control the flows for all the needs of this type of application, in particular so as to regulate the exchanges in the heat exchangers 19, 23, to regulate the feed flows according to the reaction, to balance the stacks between them, etc. Apart from the example described here, the collector base 2 is adapted, by its constitution, to receive as many heat exchangers, valves, or other elements, as necessary according to the flow control specific to a particular application.

[0097] The collector base 2 has a configuration of an assembly of layers of material 9 making it possible to accommodate the various fluidic functions relating to flow control, heat exchange, valve control, or others, within the various levels created by the layers of material 9.

[0098] The schematic example of Figure 1 gives a first simplified example in which the heat exchangers 19, 23 are housed in one of the layers of material 9-1. The valves 17, 21, 25, 27 are housed in another layer of material 9-2. The conduits 11, 12, 13, 14 are each housed in a layer of material 9-3, by means of longitudinal conduits. The conduits 16, 18, 20, 22, 24 and 26 extend transversely, by means of cross conduits, between different layers of material 9.

[0099] The illustration in Figure 1 is of course given as an illustrative example, the different components and functions housed by the collector base 2 being able to be distributed differently between the layers of material 9.

[0100] Figure 2 illustrates a practical example of the collector base 2, shown alone. In this example, the collector base 2 is intended for a single stack of electrochemical cells.

[0101] This collector base 2 comprises on its support surface 3 four connection orifices 28 each intended to be connected to the fluid circuit of the stack of electrochemical cells, to supply or collect the reaction fluids. In this example, in the same way as in FIG. 1, these four connection orifices 28 correspond to the fuel supply inlet, the fresh air supply inlet, the depleted fuel outlet, the depleted air outlet.

[0102] The stack of electrochemical cells is mounted on the support surface 3 of this collector base 2, with clamping means such as those mentioned previously, so that the connection at the connection orifices 28 is sealed. Gaskets can be used to ensure this sealing. Figure 2 also illustrates the conduits for supplying and collecting the reaction fluids, which open onto a lateral face of the collector base 2 via lateral connections 52, 53, 54, 55. These lateral connections 52, 53, 54, 55 are connected to the rest of the fluid circuit associated with the reactor (fuel source, air treatment, etc.).

[0103] Each of these lateral connections 52, 53, 54, 55 is connected to a supply or collection conduit 11, 12, 13, 14. The invention makes it possible to place these inlet and outlet connections 52, 53, 54, 55 on any face of the collector base 2.

[0104] The different layers of material 9 constituting the collector base 2 can be of different thicknesses depending on the functions they accommodate. In this example, figure 2 is a practical embodiment of all the functions illustrated schematically in figure 1.

[0105] Figure 3 is an exploded view of the different layers of material 9 of the collector base 2 of Figure 2. The layers of material 9 may comprise positioning means, such as positioning orifices 29, for implementing the manufacturing method.

[0106] The layers of material illustrated in this example are:

[0107] - a layer of material 9A, at the bottom of the stack, which is a layer of solid material intended to seal this face of the collector base 2;

[0108] - a layer of material 9B which comprises a longitudinal groove 30 which is adapted to form a longitudinal flow duct, which is transverse to the stacking direction. In this example, this longitudinal flow duct is perpendicular to the stacking direction;

[0109] - a layer of material 9C which comprises two cross-holes 31 adapted to form a cross-hole duct which extends substantially in the stacking direction. Each of the cross-hole ducts thus formed is arranged opposite the cross-hole duct constituted by the longitudinal groove 30 located on the layer of material 9B below. In this example, the two cross-holes 31 are each arranged opposite one end of the longitudinal groove 30 so that fluid communication is possible between the volume delimited by the longitudinal groove 30 and these cross-hole ducts formed by the cross-holes 31;

[0110] - a 9D material layer which hosts a heat exchange function and which is itself made up of a stack of sub-layers of material, described later;

[0111] - a layer of material 9E which comprises two cross-holes 31;

[0112] - a layer of material 9F which comprises several cross-holes 31 and two longitudinal grooves 30 which form, in the same way as for the layers of material 9B and 9C, longitudinal flow conduits and cross-hole conduits;

[0113] - a layer of material 9G which comprises different cross-member orifices 31;

[0114] - a layer of 9H material which hosts a heat exchange function and which is itself made up of a stack of sub-layers of material, described later;

[0115] - a layer of material 9I comprising several cross-holes 31;

[0116] - a layer of material 9J comprising cross-holes 31 as well as longitudinal grooves 30 extending along two portions at right angles;

[0117] - a layer of material 9K comprising cross-holes 31, the surface of this layer of material 9K constituting the support surface 3 of the collector base 2, these cross-holes 31 thus constituting the connection holes 28 described previously.

[0118] The layers of material 9 may consist of rigid plates secured in a sealed manner. These rigid plates are made of a material generally suited to the application, in particular resistant to high temperatures, such as refractory alloys, in particular nickel-based steels. The longitudinal grooves 30 and the cross-member holes may, for example, be machined beforehand in these plates, or the plates may be molded or produced by additive manufacturing. Furthermore, the layer of material 9K of FIG. 3 may be of a different material from the material used for the other layers 9 of FIG. 3, in order to facilitate sealing between the stack 1 and the collector base 2. This layer of material 9K may be of the same material as the end plate of the stack (for example in a particular stainless steel), so as to ensure thermomechanical compatibility between the stack 1 and the base of the collector base 2.In this case, heterogeneous welding between the materials chosen for this layer of 9K material and for the rest of the collector base 2 is permitted within the framework of the invention, and can be carried out in particular by the diffusion welding techniques described below.

[0119] The longitudinal grooves 30 are defined as grooves which extend in the material of a layer of material 9, that is to say which extend along a median plane which is the same as the median plane of the corresponding layer of material 9. The longitudinal grooves preferably open onto both faces of the layer of material 9.

[0120] The longitudinal grooves 30 may be rectilinear (as in the material layers 9B and 9F). These longitudinal grooves 30 may also have parallel sides, and thus delimit a longitudinal flow conduit which is parallelepipedal.

[0121] The longitudinal grooves 30 may also extend along several portions forming an angle between them (as in the material layer 9J), delimiting a hollow space with at least one change of direction in the plane of the material layer. In the example of the material layer 9J, the longitudinal groove 30 is an L-shaped groove, extends along two portions at right angles, and therefore has a change of direction in the plane.

[0122] The cross-member orifices 31 are orifices passing through the corresponding material layer 9. Several cross-member orifices 31 of several material layers can be superimposed to together form a cross-member duct which extends over several thicknesses of material 9.

[0123] In the present example, the volume delimited by the longitudinal grooves 30 is parallelepipedal, and the cross-holes 31 have a square-shaped outline, with the side of the square equal to the width of the longitudinal grooves 30, so as to delimit longitudinal flow conduits 30 and cross-holes 31 of the same section and create fluid continuity. The thickness of the different layers of material 9 carrying the longitudinal grooves 30 is also adapted for this purpose.

[0124] The arrangement of the various longitudinal grooves 30 and the cross-holes 31 is given here for illustrative purposes to describe the possibility of cooperation between the layers of material in order to form highly compact fluid circuits.

[0125] For example, the longitudinal groove 30 of the material layer 9B delimits an internal hollow volume (forming a transverse flow conduit) which is delimited laterally by the width of the groove, which is delimited vertically by the thickness of the material layer 9B, with below a solid portion of the material layer 9A, and above a solid portion of the material layer 9C. At the two ends of this longitudinal flow conduit, the two transverse orifices 31 of the material layer 9C allow a flow of the fluid vertically from this longitudinal flow conduit towards the material layer 9D.Thus, a fluid leaving the material layer 9D through a cross-hole 31 is conducted to the longitudinal flow conduit formed by the longitudinal groove 30 of the material layer 9B, this fluid then travels through this longitudinal flow conduit to the end, thus bypassing the material layer 9D, and returns through the other cross-hole 31 until returning to the material layer 9D. A bypass function for a heat exchanger can thus be implemented, in an extremely compact manner, at low cost, and adapted to the constraints specific to solid oxide electrochemical reactors.

[0126] Depending on the needs of a particular fluidic architecture, the longitudinal grooves 30 and the cross-holes 31, as well as the layers of material 9, allow multiple combinations.

[0127] Figure 4 is an exploded view of the material layer 9D of Figure 3. This figure illustrates the composition of this material layer 9D which hosts a heat exchange function. The material layer 9D is itself produced in the form of a stack of sub-layers of material, hereinafter referred to as material sheets 91. These material sheets 91 are stacked in the same way as the material layers 9.

[0128] Each sheet of material 91 also comprises cross-holes 31 intended to form cross-ducts which extend in the stacking direction (from top to bottom in FIG. 4). These sheets of material 91 each further comprise (except the top sheet of material) a heat exchange thickness 32, 33 for the function of heat exchange between two fluids.

[0129] In the example illustrated, the top sheet of material 91, which constitutes the top face of the layer of material 9D, comprises the four cross-holes 31 visible in FIG. 3 and constituting an inlet and an outlet for a first fluid as well as an inlet and an outlet for a second fluid. The heat exchange function takes place between these two fluids, without mixing. The different cross-holes 31 of the sheets of material 91 create cross-hole conduits channeling these two fluids vertically over the entire thickness of the layer of material 9D (see arrows 34 and 35), by putting the first fluid in communication with each end of the heat exchange thicknesses 32 concerning it, and by putting the second fluid in communication with lateral parts of the heat exchange thicknesses 33 concerning it.

[0130] The heat exchange thicknesses 32, 33 are alternated and stacked in a sealed manner, with the stacking of the layers 91 in a sealed manner.

[0131] Figure 5 is an illustrative view of the heat exchange thickness 32 and Figure 6 is an illustrative view of the heat exchange thickness 33.

[0132] In Figures 5 and 6, these heat exchange thicknesses 32, 33 are seen from above, making visible the walls forming conduits 34, 35 channeling the fluid. Figure 7 is a sectional view of the heat exchange thickness 32 or the heat exchange thickness 33. These walls project from a base plate.

[0133] Figures 5 and 6 are illustrative examples that are both simple and inexpensive. Any other pipe design suitable for heat exchange can be considered. In the example illustrated, the exchangers are co-current, and it is particularly possible to provide a variant with counter-current exchangers.

[0134] The stacking of the sheets of material 91, each with their heat exchange thickness 32, 33, also creates the stacking of these heat exchange thicknesses 32, 33. The process for sealing the stacking of the sheets of material 91 (bonding, additive manufacturing, welding and in particular solid state diffusion welding described later, etc.) will also seal, in the same operation, the heat exchange thicknesses 32, 33. The heat exchanger 23 is thus formed within the layer of material 9D.

[0135] In this example of the 9D material layer, one of the fluids also exits the 9D material layer through the cross-holes 31 of the last material layer, in order to multiply the possibilities of fluid paths.

[0136] Figure 8 is an exploded view of the material layer 9H of Figure 3. In this example, the material layer 9H is also made up of an assembly of material sheets 92, in the same way as for the material layer 9D, except that one of these material sheets 92A is thicker than the others and directly houses the elements of a heat exchange function.

[0137] The other sheets of material 92 also comprise, as before, cross-holes 31 and longitudinal grooves 30 creating longitudinal flow conduits and cross-hole conduits.

[0138] As for the thicker sheet of material 92A, it also includes a housing 36 intended to receive the heat exchanger 19.

[0139] The longitudinal and transverse flow ducts of this material layer 9H make it possible to arrange the flows allowing a fluid to pass through the heat exchanger 19 according to layers, and another fluid to pass through this exchanger 19 according to other layers in a sealed manner, to carry out the heat exchange. The heat exchanger 19 comprises for this purpose inlet or outlet holes 38, and the ducts of the material layer 9H are arranged to supply these holes 38 with two fluids without mixing. The heat exchanger 19 can be produced in a single block, for example by additive manufacturing or machining.

[0140] Advantageously, according to the present example, the heat exchanger 19 is preferably produced by an assembly of layers.

[0141] Figure 9 is an exploded view of this heat exchanger 19 according to this variant. The heat exchanger 19 is thus produced by an alternating assembly of solid plates 39, conduits 40 for a first fluid, and conduits 41 for a second fluid.

[0142] As illustrated in Figure 1, the collector base 2 can also integrate valve functions.

[0143] Figure 10 is a schematic view illustrating an example of the routing of the transverse flow conduits and the cross conduits, which are constituted by the longitudinal grooves 30 and the cross orifices 31, corresponding to the collector base 2 of Figure 2. Figure 10 is a view which illustrates these conduits in negative: in this view, the layers of material 9 are made transparent (and are therefore invisible in the figure) and the hollow spaces delimited by the longitudinal grooves 30 and the cross orifices 31 are materialized by solid shapes. Figure 10 thus illustrates the longitudinal flow conduits 42 which extend substantially perpendicular to the stacking direction, and the cross conduits 43 which extend substantially parallel to the stacking direction.

[0144] This figure 10 makes visible the possible junctions between the different conduits created by the cross-member orifices which open into the longitudinal grooves. For example, the bypass function of the exchanger 23, mentioned previously, carried out within the layer of material 9B, is pointed out by the arrow 44 in figure 10.

[0145] Exchanger 19 housed by material layer 9H is also visible in this figure.

[0146] Figure 10 shows the possibilities of nesting the different fluid circuits and the compactness obtained thanks to the arrangement described. The valve functions are advantageously obtained by valves inserted in the conduits 42, 43. Advantageously, these valves comprise shut-off flaps 47 arranged in the conduits 42, 43. The shut-off flaps 47 are blades of material whose shape is adapted to close the conduit 42, 43 and which are for example inserted in lateral slides bordering the longitudinal grooves 30 which constitute the conduit to be closed. These slides can be simple grooves perpendicular to the direction of flow in the conduit 42, 43.

[0147] Figure 10 shows three closure flaps 48. Figures 11 and 12 are sectional views illustrating the arrangement of a closure flap 47 arranged between three layers of material 9X, 9Y, 9Z. The middle layer of material 9Y has a longitudinal groove 30 forming the transverse flow duct 42 to be closed, and two adjacent layers of material (from above and below in the figures) delimit this duct.

[0148] The shutters 47 can thus be arranged by translation inside the longitudinal groove 30, or outside in a housing 49 provided in an adjacent layer of material 9Z.

[0149] The shutters 47 are actuated by control rods 48 passing through the different layers of material 9 until they open outside the collector base 2. The collector base 2 may comprise external actuators adapted to actuate the control rods 48. The advantage of the control rods 48 is in particular to move the actuators into the cold zone. Alternatively, these actuators may also be housed directly in one of the layers of material 9.

[0150] The control rods 48 pass through the different layers of material 9 via a passage 50, which is made by any means (machining, drilling, etc.). The passages 50 can be made by a stack of orifices in the different layers of material 9 that the control rod 48 must pass through.

[0151] In Figure 10, two shut-off flaps 47 close cross-flow ducts 42 directly in the duct (the two lower shut-off flaps 47 in the view of Figure 10). Figure 10 illustrates another variant, corresponding to the material layer 9F of Figure 3, where the shut-off flap 47 closes a passage between two adjacent cross-flow ducts 42, formed by two parallel longitudinal grooves 30 (the uppermost shut-off flap 47 in the view of Figure 10). The valve function is thus integrated in a very compact manner.

[0152] These different positions of shutters 47 illustrate the numerous possibilities offered by the arrangement and the associated compactness.

[0153] The shutters 47 can also close cross-ducts 43, their control rods 48 then opening onto another lateral face of the collector base 2. The shutters 47 and the control rods 48 can then be arranged between the layers of material 9.

[0154] Particularly advantageously, the shut-off flaps 47 may not include sealing elements, other than their mechanical adjustment in sliding grooves. Even a slight leak is not detrimental, since these are conduits each channeling a single fluid, and sufficient shut-off is thus obtained, reliably and at low cost, to control the different flows.

[0155] Sealing bellows 51 are sufficient to ensure sealing. The control rod 48 can be actuated to completely close the cross-flow conduit 42 (Figure 11), or to only partially close it (Figure 12).

[0156] This collector base 2 can also be produced using inexpensive manufacturing processes and with quality levels compatible with industrialization.

[0157] The different layers of material 9, as well as the possible sheets of material 91, 92, constituting each of these layers of material can be produced directly by conventional machining of solid plates (obtained by forging, rolling, etc.) or by additive manufacturing, for example by powder bed fusion, with a metal powder of a metal compatible with the application of a solid oxide electrochemical reactor and corresponding temperatures. Alternatively, according to a particularly advantageous method, the collector base 2 is produced by an assembly of layers of solid material with welding between the layers of solid material.

[0158] All layers, whether material layers 9 or material sheets 91, 92, are first prepared with the production of longitudinal grooves 30, cross-holes 31, and any other elements such as positioning holes 29, housings 36 for exchanger, etc., in metal plates, for example by machining, drilling, laser or water jet cutting, etc.

[0159] The different layers of material 9, the possible sheets of material constituting them 91, 92, as well as the different heat exchange thicknesses 31, 32, and the possible layers 39, 40, 41 constituting an exchanger 19, as well as the valves, are thus first of all stacked in the correct order.

[0160] The different thicknesses of material are then glued or welded together.

[0161] Particularly advantageously, these thicknesses are assembled by solid-state diffusion welding. For this purpose, the metal plates are stacked and the produced block is placed in a sealed container, made of welded sheets for example. The assembly is then subjected to a first hot isostatic compression cycle, that is to say a rise in temperature and a rise in external pressure, to cause the layers to begin to weld together without modifying the shape of the conduits 42, 43, and without causing them to collapse.

[0162] The objective of this first cycle is to obtain sufficient welding of the surfaces in contact between the different plates. After cooling, the container is then pierced in order to put the conduits 42, 43 in communication with the atmosphere outside the assembly.

[0163] Another consolidation cycle is then carried out in order to at least partially reabsorb the residual pores at the interfaces between the plates.

[0164] For example, for AISI 316L stainless steel plates, the temperature of the first cycle can be around 1,000°C, and the pressure around 50 to 100 bar; and for the consolidation cycle, a temperature of around 1,100°C, and a pressure of around 1,000 bar.

[0165] At the end of the process, the faces of the collector base 2 are then machined to reveal the fluid circuit connections, to which the fluid inlets and outlets will be connected, as well as the cell stacks 1.

[0166] Alternative embodiments can be implemented. For example, the cross flow conduits 42 and the cross conduits 43 are here of square or rectangular profile, allowing the advantages described in compactness and cost. However, any other conduit profile can be implemented with the layers of material 9.

Claims

CLAIMS 1. Collector base (2) for a solid oxide electrochemical reactor, comprising a support surface (3) adapted to support at least one stack of solid oxide electrochemical cells (1), and comprising inlet and outlet connections (52, 53, 54, 55) for the fluids used in the solid oxide electrochemical reactor, this collector base (2) being characterized in that it is formed from an assembly of layers of material (9) superimposed in a sealed manner, in a stacking direction, and in that: - at least one of these layers of material (9) comprises a longitudinal groove (30) passing through the thickness of the layer of material (9), and forming a longitudinal flow conduit (42) which is substantially perpendicular to the stacking direction; - at least one of these layers of material (9) comprises a cross-section orifice (31) forming a cross-section conduit (43) in the thickness of the layer of material (9), this cross-section conduit (43) extending substantially in the stacking direction and being arranged opposite said longitudinal flow conduit (42).

2. Collector base according to claim 1, characterized in that the support surface (3) comprises connection orifices (28) for connecting to the collector base (2) said at least one stack of solid oxide electrochemical cells (1), each of said inlet and outlet connections (52,53,54,55) being fluidically connected to one of said connection orifices (28) by at least one longitudinal flow conduit (42) and at least one cross conduit (43).

3. Collector base according to one of the preceding claims, characterized in that said longitudinal groove (30) defines the longitudinal flow duct (42) by its side walls, and this longitudinal flow duct (42) is further delimited by solid portions of the two adjacent layers of material (9).

4. Collector base according to one of the preceding claims, characterized in that the cross-member orifice (31) is superimposed on a cross-member orifice crosspiece (31) of the same contour on an adjacent layer of material (9), said crosspiece conduit (31) being delimited by the side walls of several crosspiece orifices (31) aligned on several adjacent layers of material (9).

5. Collector base according to one of the preceding claims, characterized in that at least one longitudinal groove (30) is a rectilinear groove.

6. Collector base according to claim 5, characterized in that said longitudinal groove (30) delimits a parallelepiped hollow space.

7. Collector base according to one of the preceding claims, characterized in that at least one longitudinal groove (30) is a groove extending along at least two portions forming an angle between them, delimiting a hollow space with at least one change of direction in the plane of the corresponding layer of material.

8. Collector base according to one of the preceding claims, characterized in that at least one cross-hole (31) is a through hole of square outline.

9. Collector base according to claim 8, when it depends on one of claims 5 to 7, characterized in that the width of the longitudinal groove (30) is substantially equal to the side of the square forming the outline of the crosspiece orifice (31).

10. Collector base according to one of the preceding claims, characterized in that at least one layer of material (9) consists of an assembly of sheets of material (91, 92) superimposed in a sealed manner, following the stacking direction.

11. Collector base according to claim 10, characterized in that several of said sheets of material (91) each have a thickness heat exchange (32,33), the heat exchange thicknesses (32,33) being superimposed.

12. Collector base according to claim 11, characterized in that the heat exchange thicknesses (32, 33) are adjacent to at least one of said cross-member orifices (31) or at least one of said longitudinal grooves (30).

13. Collector base according to one of claims 11 or 12, characterized in that said heat exchange thicknesses (32, 33) are superimposed in an alternating and sealed manner, with the alternation of a heat exchange thickness (32) for a first fluid, and a heat exchange thickness (33) for a second fluid.

14. Collector base according to one of the preceding claims, characterized in that at least one layer of material comprises a housing (36) and a heat exchanger (19) arranged in this housing (36), this housing (36) being in fluid communication with at least one of said cross-member orifices (31) or at least one of said longitudinal grooves (30).

15. Collector base according to claim 14, characterized in that said housing (36) is a through cavity formed in the thickness of the layer of material (9), and in that the heat exchanger (19) is parallelepipedal.

16. Collector base according to one of claims 14 or 15, characterized in that the heat exchanger (19) is made up of heat exchange conduits (40, 41) superimposed in an alternating manner.

17. Collector base according to one of the preceding claims, characterized in that it comprises at least one valve arranged in one of said longitudinal flow conduits (42) or cross conduits (43).

18. Collector base according to one of the preceding claims, characterized in that it comprises at least one valve arranged between two longitudinal flow conduits (42) formed in the same layer of material (9).

19. Collector base according to one of claims 17 or 18, characterized in that said valve comprises a shut-off flap (47) sliding transversely to the corresponding conduit (42, 43).

20. Collector base according to claim 19, characterized in that it comprises a housing (49) for the closure flap (47) in a layer of material (9) adjacent to the layer of material (9) which comprises the conduit (41, 42) adapted to be closed by said closure flap (47).

21. Collector base according to one of claims 17 to 20, characterized in that said valve is actuated by a control rod (48) which extends into a passage (50) formed in at least one layer of material (9).

22. Solid oxide electrochemical reactor comprising: - at least one stack of solid oxide electrochemical cells (1) which each comprise a layer of solid electrolyte arranged between two layers of electrodes; - a collector base according to one of claims 1 to 21.

23. Method of manufacturing a collector base according to one of claims 1 to 21, characterized in that it comprises steps of superimposing said layers of material (9), in a sealed manner, in a stacking direction.

24. Method of manufacturing a collector base according to claim 23, characterized in that it comprises the following steps: - forming said layers of material (9) by making said longitudinal grooves (30) and said cross-holes (31) in rigid metallic layers of material; - superimposing said layers of material (9) in the stacking direction; - carry out solid-state diffusion welding by subjecting the stack of layers of material (9) to a predetermined clamping and a predetermined temperature.

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