Installation and production process for fuel cell stacks

Abstract

The invention relates to an installation (10) for the production of solid oxide stacks (14), comprising: - a cylindrical enclosure (12) with principal axis A in which the stacks (14) are to be placed coaxially with the principal axis A; - a first shaft (22) and a second shaft (24) between which the stacks (14) are placed; - heating elements (32) arranged in the enclosure (12), characterized in that the principal axis A of the enclosure (12) is horizontal and perpendicular to a vertical axis with respect to Earth's gravity. Figure 3.

Description

Title of the invention: Installation and method for producing fuel cell stacks technical field

[0001] The invention relates to an installation for the production of solid oxide stacks operating at high temperature. Such stacks are, for example, high-temperature solid oxide electrolyzers or high-temperature solid oxide fuel cells.

[0002] The invention more particularly proposes an installation that provides a homogeneous distribution of forces in order to limit the influence of Earth's gravity in the application of an axial compression force to the stacks. The invention also proposes an installation in which the heat distribution is homogeneous for all the stacks during the production process. PREVIOUS STATE OF THE ART

[0003] A solid oxide electrolyzer or a solid oxide fuel cell, commonly referred to by the acronyms SOEC (Solid Oxide Electrolyzer Cell) or SOFC (Solid Oxide Fuel Cell), consists of an alternating assembly of a plurality of electrochemical units and interconnectors, with one electrochemical unit interposed between two interconnectors. Each electrochemical unit, also called an electrolysis cell, comprises two electrodes, namely an anode and a cathode, between which an electrolyte is disposed.

[0004] The alternating assembly of electrochemical units and interconnectors forms what will be referred to hereafter as a stack, commonly referred to as "stack".

[0005] During a production step of a stack, the assembly of electrochemical units and interconnectors is compressed along its main axis and then installed in a heated chamber.

[0006] According to a known embodiment, the main axis of the assembly of electrochemical units and interconnectors is oriented vertically and the compression is also carried out vertically, according to Earth's gravity, that is to say that the elements constituting the stacks are arranged horizontally and are assembled vertically one on top of the other.

[0007] The production process for manufacturing a functional stack is carried out by performing a predefined thermal cycle under constant stress and supplying the chamber with a purging gas to protect the stack components against high-temperature oxidation. During this thermal cycle, the sealing of each electrochemical unit and each The stacking layer forms, with heating transforming the sintered glass slip, present on the interconnecting plates, into a glass-ceramic. The gas flow at temperature also reduces the electrochemical cell mounted at the core of the interconnecting plates.

[0008] This production process combines the application of mechanical force with a temperature cycle, which results, among other things, in a significant variation in the stack height (between 30 and 50% of the initial height). This process must therefore be carried out in a controlled manner to guarantee conformity of the stack geometry.

[0009] Proper vertical guidance of the stacking elements during this operation is necessary. Furthermore, the temperature within the chamber and the mechanical compression of the stacking elements must be controlled and uniform throughout the entire manufacturing process, which may exceed 48 hours, and this must be maintained throughout the entire height of the stack.

[0010] The equipment used today consists of vertical axis furnaces which have, in their lower part, a hearth equipped with a rigid support on which the elements constituting one or more stacks are assembled. These furnaces have, in their upper part, a ceiling with an axial opening allowing the passage of a rod / crossbeam which serves to compress the assembly of the elements constituting the stack(s). External mechanical devices such as jacks, springs, or gravity loads coupled with a lever arm are used to ensure the maintenance of a constant force. The vertical guidance of the elements constituting the stack(s) is ensured by a column-type device located either internally or externally to the stacks.

[0011] Such a manufacturing process has certain drawbacks. In particular, the total height of the assembly comprising the elements constituting the stack(s) is limited due to constraints related to Earth's gravity.

[0012] Indeed, each element constituting the stack(s) is subjected to the continuous compressive force which is exerted on all the elements constituting the stack(s), as well as to the self-weight of all the elements which are located above the element considered.

[0013] Consequently, the elements located vertically at the bottom of the stack are subjected to an axial force which is greater than the force exerted on the elements located at the top of the stack.

[0014] This constraint is all the more pronounced in multi-stack type structures made up of several sub-stacks which incorporate several thick and therefore heavier end plates.

[0015] Also, such a vertical orientation of the stack of elements presents a difficulty in ensuring sufficiently precise guidance during the slump phase axial of the structure in connection with the transformation of the glass frit which goes from a solid state to a viscous state before forming a glass-ceramic structure.

[0016] Finally, the vertical orientation of the assembly presents a disadvantage in terms of thermal performance.

[0017] Indeed, in a vertical structure, the effects of convection during the heating / cooling phases, combined with heat losses in the upper part of the structure due to mechanical support devices (heat loss by conduction in the support rods and the presence of openings in the furnace ceilings), necessitate precise multi-zone control to ensure a homogeneous temperature throughout the entire height of the assembly. This control is all the more complex to implement as the height of the assembly gradually decreases during the process.

[0018] It is now known that differences of a few tens of degrees have a very strong impact on the viscous behavior and the crystallization kinetics of the seal during its formation.

[0019] The invention aims to provide an installation and a method for producing at least one stack of electrochemical cells, thereby reducing or even eliminating the drawbacks associated with vertically oriented production. Description of the invention

[0020] The invention provides an installation for the production of solid oxide stacks, which includes

[0021] - a cylindrical enclosure with principal axis A in which the stacks are intended to be installed coaxially with the main axis A,

[0022] - a first tree and a second tree between which the stacks are placed in place,

[0023] - heating elements arranged within the enclosure,

[0024] characterized in that the main axis A of the enclosure is horizontal and perpendicular to a vertical axis according to terrestrial gravity.

[0025] Such a horizontal orientation of the principal axis A of the enclosure ensures homogeneity of the axial support force exerted on the components of the stack or plurality of stacks. Indeed, the action of Earth's gravity no longer plays a role in this axial force. Furthermore, there is no longer a heat gradient along the vertical height due to thermal convection effects, thus enabling thermal regulation within the enclosure.

[0026] Preferably, the enclosure includes means for driving the stacks and shafts, rotating around the main axis A.

[0027] Preferably, the drive means comprise a motor coupled to the first shaft.

[0028] Preferably, the heating elements consist of a plurality of straight elements parallel to the main axis A, which are distributed around the main axis A and around the stacks when the stacks are installed in the enclosure.

[0029] Preferably, the installation includes at least one radial support device which achieves centering of the stacks during their rotation around the main axis A.

[0030] Preferably, the radial support device comprises a longitudinal bar which is movable in a radial direction relative to the main axis A and comprises means for driving the longitudinal bar in the radial direction.

[0031] Preferably, the installation comprises a plurality of radial support devices which are distributed around the main axis A.

[0032] Preferably, at least one tree among the first tree and the second tree is axially translationally movable along the main axis A relative to the enclosure.

[0033] Preferably, the installation includes a cradle mounted for rotation inside the enclosure around the main axis A and in which the stacks are placed coaxially to the main axis A.

[0034] Preferably, the cradle includes an end flange which is connected to a cradle drive motor rotating around the main axis A.

[0035] Preferably, the cradle has a central hub on either side of which the stacks are arranged.

[0036] Preferably, the two trees are mobile in opposite and simultaneous displacements along the main axis A.

[0037] Preferably, the installation includes a linkage connecting an actuator to the shafts, which transforms a displacement of the actuator into opposite and simultaneous displacements of the shafts.

[0038] Preferably, the cradle carries a plurality of longitudinal bars intended to bear against the stacks.

[0039] Preferably, the installation includes a device for positioning the stacks coaxially with each other in which the stacks are assembled with their main axes B vertical, according to Earth's gravity.

[0040] Preferably, the installation includes means for clamping the stacks to allow their handling before they are placed in the enclosure. Brief description of the drawings

[0041] [Fig-1] is a schematic perspective representation of an installation according to the invention.

[0042] [Fig.2] is a schematic axial section representation of the installation represented in [Fig.1].

[0043] [Fig.3] is a two-step schematic representation of the installation of the stacks in the guiding tooling.

[0044] [Fig.4] is an illustration of the cooperation of the clamping tooling with the stacks.

[0045] [Fig.5] is a side view in axial section of the installation, in which the stacks are placed in the enclosure before the thermal cycle is implemented.

[0046] [Fig.6] is a schematic perspective representation of an installation adapted to stacks of square section according to a second embodiment of the invention.

[0047] [Fig.7] is a schematic perspective representation of a rotating cradle adapted to the implementation of the second embodiment of the invention.

[0048] [Fig.8] is a side view in axial section of the installation, in which the stacks are placed in the enclosure before the thermal cycle is implemented. DETAILED DESCRIPTION OF THE INVENTION

[0049] For the description of the invention, the orientations according to the reference frame V, L, T indicated in the figures will be adopted without limitation, corresponding respectively to a vertical direction V, a longitudinal direction L and a transverse direction T.

[0050] Figure 1 shows an installation 10 intended for the production of stacks of several layers forming electrochemical cells.

[0051] SPRING

[0052] The installation includes an enclosure 12 in which a plurality of stacks 14, commonly called "stacks" and which are represented in [Fig.3], are produced.

[0053] Each stack 14 consists of an alternation of a plurality of electrochemical units and interconnectors, as previously stated. Such stacks 14 form solid oxide electrolyzers or solid oxide fuel cells.

[0054] According to a first aspect of the invention, the installation 10 is adapted to the production of stacks 14 each having a main cylindrical shape of revolution having a main axis B, a cylindrical outer wall and two axial end faces 20.

[0055] The enclosure 12 consists of an element of revolution about a principal axis A which is oriented horizontally, that is to say perpendicular to Earth's gravity. Here, the principal axis A is oriented along the longitudinal direction L.

[0056] The cylindrical interior volume of the enclosure 12 is thus also cylindrical in shape and has a horizontal principal axis A. To allow access to its interior volume, the enclosure 12 is made in two parts, preferably two halves. shells 16, of which one shell 16 is fixed to a support chassis 18 and the other half-shell 16 is removable from the first half-shell 16.

[0057] The stacks 14 are assembled together according to a method that will be described later, to form an assembly in which the stacks are joined by their axial end faces 20 and in which the principal axes of the stacks coincide. The assembly then forms a cylindrical element having a principal axis coincident with the principal axis B of each stack 14.

[0058] The assembly thus formed is placed in the enclosure 12 so that its main axis B coincides with the main axis A of the enclosure 12. SUPPORT AXES

[0059] The enclosure 12 comprises two shafts 22, 24 for supporting and driving the assembly in rotation around the main axis A of the enclosure. The two shafts 22, 24 are arranged axially on either side of the assembly, with respect to the main axis A of the enclosure 12.

[0060] As can be seen in [Fig. 2], a first shaft 22, located to the right of [Fig. 2], is mounted at a first longitudinal end of the enclosure 12. It passes through an axial end wall 26 of the enclosure 12 and is guided in rotation about the main axis A relative to this axial end wall 26. Thus, one section of this first shaft 22 is arranged within the interior volume of the enclosure, and a second section of the first shaft 22 is arranged outside the enclosure 12. This second section of the first shaft 22 is connected to a drive motor 28 which is fixed to the frame 18.

[0061] The second shaft 24 is mounted at the second longitudinal end of the enclosure 12, i.e. here at the left end in [Fig.2]. This second shaft 24 passes through a second axial end wall 30 of the enclosure 12 and is mounted movable relative to this second axial end wall 30 so that it is free to rotate about the main axis A of the enclosure 12 and so that it is mounted movable in translation along this main axis A of the enclosure 12.

[0062] The installation 10 includes means (not shown) for driving the second shaft 24 in axial displacement to put the stack 14 under axial pressure during the implementation of the thermal cycle.

[0063] The second shaft 24 is also a hollow shaft; it defines at least one conduit 48 connecting the interior volume of the enclosure 12 with a supply of purging gases used during the thermal cycle. These purging gases have a protective function for the components; for example, hydrogen prevents the oxidation of materials at high temperatures.

[0064] Suitable guiding elements (not shown) are arranged between each shaft 22, 24 and the wall 26, 30 of the enclosure 12 associated with it to achieve both a guidance of each shaft 22, 24 and isolation of the internal volume of the enclosure from the outside during the process. HEATING ELEMENTS

[0065] The enclosure 12 also includes heating elements 32 which are distributed along the axial length of the enclosure and which are distributed regularly around the main axis A.

[0066] Preferably, as shown in the figures, each heating element 32 consists of a straight longitudinal element parallel to the main axis A, which is mounted on the cylindrical central part of the enclosure 12. The longitudinal length of each heating element 32 is defined to allow for the homogeneous heating of all the stacks 14. Thus, preferably, each heating element extends along the entire longitudinal length of the enclosure 12.

[0067] The heating elements 32 are distributed around the stacks 14, when the latter are placed in the enclosure, which allows all the stacks 14 to be exposed to homogeneous heat during the heating cycle. RADIAL SUPPORT DEVICES

[0068] The enclosure 12 also includes radial support devices 34 which are designed to center the stacks 14 during the process. Indeed, as the thermal cycle progresses, the dimension of the stacks 14 along the principal axis A decreases, while their radial dimension with respect to the principal axis A increases.

[0069] Moreover, even if, during the thermal cycle, the stacks are rotated in order to balance the forces they experience from Earth's gravity, they may eventually shift relative to each other.

[0070] Thus, by using the radial support devices 34, the stacks 14 are all maintained in a good coaxial position to the main axis A, which also ensures optimal heating of them.

[0071] Here, the enclosure 12 carries three radial support devices 34; it will be understood that it can carry a different number of such devices, for example six.

[0072] Each radial support device 34 includes a longitudinal bar 36 which is intended to come into contact with the stacks 14.

[0073] The longitudinal bar 36 extends longitudinally, that is to say, it is parallel to the main axis A. Its longitudinal length, as well as its longitudinal position in the enclosure 12, are defined so that the longitudinal bar is in contact with all the stacks 14 during the thermal cycle.

[0074] Each radial support device 34 also includes guide rods 38 for the longitudinal bar 36 moving in a radial direction relative to the main axis A.

[0075] Each rod 38 is thus oriented radially with respect to the principal axis A and passes through the cylindrical wall of the enclosure 12. The wall of the enclosure 12 has, for this purpose, a cylindrical bearing surface 40 associated with each rod 38 and through which the associated rod 38 passes. The cylindrical bearing surface 40 also includes sealing means (not shown) to prevent any gas leakage from the enclosure 12.

[0076] Here, there are two rods 38, they are parallel to each other and are offset longitudinally. They are connected together at their inner radial ends by the longitudinal bar 36 and at their outer radial ends, which are located outside the enclosure 12, by a connecting bar 42 with a main longitudinal orientation.

[0077] Each radial support device 34 also includes means for driving the longitudinal bar 36, and therefore the rods 38 and the connecting bar 42, in radial movement in the direction of the main axis A or away from the main axis A.

[0078] The radial displacement drive in the direction of the main axis A is achieved by means of a cylinder 44 which acts on the connecting bar 42 to bring it closer to the wall of the enclosure 12.

[0079] The radial displacement drive away from the main axis A is achieved by means of at least one spring 46, here two springs 46, each of which is radially compressed between the connecting bar 42 and the wall of the enclosure 12.

[0080] Thus, by controlling the cylinder 44, it is possible to modify the distance of the longitudinal bar 36 relative to the main axis A, as well as the support force of the longitudinal bar 36 against the stacks 14. GUIDING TOOLS

[0081] As previously stated, before their placement in the internal volume of the enclosure 12, the stacks 14 are assembled with each other to form an assembly in which the stacks 14 are joined by their axial end faces 20 and their principal axes B are coincident.

[0082] For this purpose, as can be seen in [Fig. 3], the stacks 14 are placed vertically one on top of the other with their principal axes B coaxial with each other. Also, a guiding tool 50 is used to position the stacks 14 coaxially with each other.

[0083] The guiding tool 50 comprises a flat, horizontal base 52 and vertical arms 54, preferably three in number, extending upwards from the base 52 and between which the stacks 14 are received. During the installation of the stacks in the guiding tool 50, the principal axes B of the stacks are oriented vertically according to Earth's gravity and the stacks 14 are held coaxial to each other by means of the vertical arms 54 between which the stacks 14 are received. CLAMPING TOOLS

[0084] When all the stacks 14 are placed on the guide tool 50, they are secured together by a clamping tool 56 shown in [Fig.4], which clamps all the stacks 14 along the axial direction of the stack.

[0085] The clamping tool 56 is here made up of two identical elements 58, it will be understood that the clamping tool 56 may include a different number of such elements 58.

[0086] Each element 58 consists of a bar which is substantially parallel to the common principal axis B of the stacks 14, i.e. which is substantially vertical when the element is placed on the guiding tooling 50.

[0087] A first end 60 of the element 58 has a lug projecting perpendicularly to the rest of the element 58, which is intended to come into contact with an axial end face 20 of a stack 14 located at one end of the set of stacks 14, preferably here against a lower axial end face 20 of the stack 14 located vertically at the bottom of the set, and therefore against a face which is in contact with the base 52 of the tooling 50.

[0088] The second end 62 of the element 58 carries a movable finger 64 which protrudes from the rest of the element and which is intended to come into contact with an axial end face of a stack 14 located at a second end of the set of stacks 14, preferably here against an upper axial end face 20 of the stack 14 located vertically at the top of the set, and therefore against a free end face of the set of stacks 14.

[0089] The position of the movable finger 64 along the element 58 is adjustable, to allow axial clamping of the stacks 14 between the movable finger and the lug, for the purpose of handling this stack of stacks 14 out of the guide tooling 50, without the stacks 14 moving relative to each other. MANUFACTURING PROCESS

[0090] In the following description, we will describe the steps which are successively implemented for the manufacturing process using an installation 10 according to the invention.

[0091] Initially, the stacks 14 are assembled with each other and coaxially with each other by using the guiding tool 50.

[0092] This assembly is carried out by installing the stacks 14 one by one in the guide tooling with their main axes B oriented vertically.

[0093] After installing all the stacks 14 that are to undergo the thermal cycle in the guiding tool 50, they are secured together using the clamping tool 56, that is, by using several elements 58 that clamp the stacks 14 together. The magnitude of the clamping force produced by the elements 58 is sufficient to hold the stacks 14 together during handling, without being so great as to damage the stacks 14.

[0094] The sub-assembly consisting of the assembled stacks 14 and the clamping tool 56 is then placed in the enclosure 12.

[0095] For this purpose, one of the half-shells 16, preferably the upper half-shell 16, is disassembled beforehand, leaving sufficient space for the installation of the sub-assembly.

[0096] The installation of the subassembly in the enclosure 12 consists first of placing the main axis B of the coaxial subassembly to the horizontal main axis A of the enclosure 12 and then positioning the subassembly between the two shafts 22, 24.

[0097] This positioning of the sub-assembly between the two shafts 22, 24 is carried out by first placing the stack assembly against the first shaft 22 and then axially translating the second shaft 24 towards the first shaft 22 to come to rest against the stack assembly 14.

[0098] Next, a first axial stress is exerted via the second shaft 24 on the stacks 14.

[0099] The amplitude of this first axial stress is at least equal to the amplitude of the clamping force exerted by the clamping tooling 56 on the stacks 14, which thus makes it possible to keep the subassembly in place between the shafts 22, 24.

[0100] Next, the elements 58 of the clamping tooling 56 are detached from the stacks 14. The stacks 14 are held in place by the axial support of the second shaft 24 on the stacks 14. The elements 58 are then stored outside the enclosure 12.

[0101] The enclosure 12 is then hermetically sealed by assembling the half-shell 16 which had previously been disassembled.

[0102] Finally, the longitudinal bars 36 of the radial support devices 34 are brought into contact with the periphery of the stacks 14.

[0103] According to an alternative embodiment, the longitudinal bars 36 of the radial support devices 34 which are associated with the lower half-shell 16 are positioned radially to support the subassembly and position it coaxially to the main axis A of the enclosure, before contact and therefore before axial support of the second shaft 24 against the stack assembly 14.

[0104] The installation 10 prior to the implementation of the thermal cycle is shown in [Fig.5].

[0105] The thermal cycle during which the stacks 14 are heated can then be implemented.

[0106] This thermal cycle consists of rotating the stacks 14 around the main axis A. For this, the motor 28 is supplied in a controlled manner to have a constant and determined rotational speed.

[0107] Also, the internal volume of the enclosure 12 is either filled with sweeping gases at a controlled flow rate and pressure, these sweeping gases are supplied into the enclosure via the conduit 48 formed in the second shaft 48 or an air vacuum is formed in the internal volume of the enclosure 12.

[0108] The support force exerted by the second shaft 24 is controlled and maintained throughout the thermal cycle to accompany the decrease in the axial dimension of the stacks 14. The possibility of displacement of the second shaft 24 along the main axis A makes it possible to compensate for the decrease in the axial dimension of the stacks 14.

[0109] Finally, the heating elements 32 are activated to heat the internal volume of the enclosure 12 and the stacks 14 homogeneously during the implementation of the thermal cycle.

[0110] The rotation of all the stacks 14 prevents the glass from flowing due to gravity when it enters a viscoplastic state. This rotational movement also ensures homogeneous heating of all the components constituting each stack 14, eliminating the convective effects observed in vertical furnaces. The peripheral radial support devices 34 ensure the guidance and proper alignment of the rotating stacks 14 during the manufacturing process.

[0111] At the end of the thermal cycle, the enclosure 12 is opened by dismantling the upper half-shell 16. The elements 58 of the clamping tooling 56 are put back in place on the stacks 14 and maintain an axial compression force on the stacks 14 to allow their manipulation without them moving relative to each other, or becoming disjointed, during the handling of the subassembly.

[0112] The possibility of moving the movable finger 64 allows the same element 58 to be mounted on all the stacks 14, whether before the implementation of the thermal cycle, in which case the dimension of each stack along its main axis B is the most important, or after the implementation of the thermal cycle, in which case the dimension of each stack 14 along its main axis B is reduced.

[0113] The second tree 24 is then moved back axially, that is to say it is moved away from the first tree 22, to decouple the subset from the trees 22, 24.

[0114] The subassembly comprising the clamping tool 56 and the stacking assembly 14 is then removed from the internal volume of the enclosure 12. The clamping tool 56 is then removed, the stacking 14 can then be integrated into a module. SECOND METHOD OF IMPLEMENTATION

[0115] Figures 6 and following show an installation adapted for the manufacture of stacks 14 of cylindrical shape with square cross-section.

[0116] Unlike the previous embodiment, during the rotation of the stacks in the enclosure 12, it is not possible to use a radial support device 34 carried by the enclosure 12, which comes into contact with the cylindrical wall of the stacks 14.

[0117] The installation includes heating elements 32 similar to those of the first embodiment, i.e. which extend at least over the entire longitudinal length of the stacks 14 when they are placed in the enclosure. ROTATING CRADLE

[0118] According to this second aspect of the invention, the maintenance of the stacks 14 in their shape is obtained by means of a rotating cradle 70 in which the stacks 14 are positioned for the implementation of the thermal cycle, and which is mounted to rotate around the main axis A.

[0119] The rotating cradle 70, shown in more detail in [Fig.7], is in main cylindrical shape of revolution coaxial with the main axis A of the enclosure 12.

[0120] It comprises a cylindrical structure 72 made in two parts 74, one part of which is removable to allow access to the internal volume of the rotating cradle, a central hub 76 and two end flanges 78.

[0121] Each end flange 78 is traversed by a shaft 22, 24. In addition, each of the two shafts 22, 24 is here mounted to slide axially relative to the end flange 78 associated with it to achieve axial clamping of the stacks against the central hub 76.

[0122] The rotating cradle 70 is driven in rotation around the main axis A by an external motor 28 which meshes with a toothed wheel 80 carried by one of the two end flanges 78.

[0123] The rotating cradle 70 further includes openings 94 formed in the two parts 74 which are designed to allow the elements 58 of the clamping tooling 56 to be deposited after the stacks 14 have been placed in the rotating cradle 70 and the latter closed. LONGITUDINAL BARS

[0124] Also, the longitudinal bars 36 are supported by the rotating cradle 70, so that they follow the stacks during their rotation around the main axis A. They are arranged inside the rotating cradle 70 and they are distributed around the main axis A to define a plurality of support planes against which a lateral face of the stacks 14 is supported.

[0125] Thus, preferably, the longitudinal bars 36 are distributed in several pairs, each pair of longitudinal bars 36 defining a support plane associated with a lateral face of the stacks 14.

[0126] The longitudinal bars 36 are further distributed over the two parts 74 of the rotating cradle 70.

[0127] Thus, the stacks 14 are first installed on the longitudinal bars of the first part 74 of the rotating cradle 70 and then, when the second part 74 of the rotating cradle 70 is assembled with the first part, the longitudinal bars 36 that it carries come to rest against the stacks 14. TWO-TREE TRAINING

[0128] As previously stated, the two shafts 22, 24 are all movable along the main axis A and clamp the stacks 14 together and against the central hub 76.

[0129] Each shaft 22, 24 has an internal end provided with a support plate 82 which is intended to bear against an axial end face 20 of the stacks 14.

[0130] The installation 10 also includes a drive device 84 for the two shafts 22, 24 in longitudinal translation towards each other to apply the clamping force of the stacks 14.

[0131] The drive device 84 includes a cylinder 86 for producing the clamping force and a linkage 88 connecting each end 90 of the cylinder 86 to an external end 92 of a shaft 22, 24 which is associated with it and which is located outside the enclosure 12. The linkage 88 is connected to each external end 92 of a shaft 22, 24 by a ball joint.

[0132] The linkage 88 distributes the force produced by the cylinder 86 evenly to the two shafts 22, 24 so that this clamping force is substantially identical on both sides of the central hub 76. The linkage 88 also causes the two shafts to move in opposite and simultaneous directions. That is to say, the linkage allows the two shafts 22, 24 to move together or apart simultaneously. MANUFACTURING PROCESS

[0133] In the following description, we will describe the steps which are successively implemented for the manufacturing process using an installation 10 according to the second embodiment of the invention.

[0134] Initially, the stacks 14 are assembled one on top of the other and coaxially to each other by the use of a guiding tool (not shown).

[0135] This assembly is carried out by installing the stacks 14 one by one in the guide tooling with their main axes B oriented vertically.

[0136] After installing all the stacks 14 that are to undergo the thermal cycle in the guiding tool 50, they are secured together using the clamping tool 56, that is, by using several elements 58 that clamp the stacks 14 together. Here, since the stacks 14 have a square cross-section, four elements 58 are used, one element 58 being positioned at each face of the stacks.

[0137] The magnitude of the clamping force produced by the elements 58 is sufficient to maintain the stacks 14 together during their handling, without being too great to damage the stacks.

[0138] The sub-assembly consisting of the assembled stacks 14 and the clamping tooling 56 is then placed in the rotating cradle 70 and therefore in the enclosure 12.

[0139] To this end, one of the half-shells 16, preferably the upper half-shell 16, is first detached from the other half-shell 16, leaving sufficient space for the installation of the sub-assembly. Similarly, the upper part 74 of the rotating cradle 70 is first detached.

[0140] The placement of the sub-assembly in the cradle consists first of positioning it on the longitudinal bars 36 which define a space complementary to the stacks 14.

[0141] The second part 74 of the rotating cradle 70 is put in place and fixed on the first fixed part 74 to close the rotating cradle 70 and to support all the longitudinal bars 36 against the side walls of the stacks 14.

[0142] Next, the two shafts 22, 24 are placed in axial support against the stacks 14 by an axial translation of the shafts 22 24 towards the stacks 14, and therefore in the direction of the central hub 76. By this axial support of the shafts 22, 24, a first axial stress is exerted on the stacks 14.

[0143] The amplitude of this first axial stress is at least equal to the amplitude of the clamping force exerted by the clamping tool 56 on the stacks 14.

[0144] Next, the elements 58 of the clamping tooling 56 are detached from the stacks 14 and are removed through the openings 94 formed in the two parts 74 of the rotating cradle 70. The elements 58 are therefore stored outside the enclosure 12.

[0145] The enclosure 12 is then hermetically sealed by assembling the half-shell 16 which had previously been disassembled.

[0146] The thermal cycle can then be implemented.

[0147] This thermal cycle consists of rotating the stacks 14 around the main axis A. For this, the motor 28 is supplied in a controlled manner to have a constant and determined rotational speed.

[0148] Also, the internal volume of the enclosure 12 is either filled with sweeping gases at a controlled flow rate and pressure, these sweeping gases are supplied via the conduit 48 of the second shaft 24 or an air vacuum is formed in the internal volume of the enclosure 12.

[0149] The axial support force exerted by the two shafts 22, 24 is controlled and maintained throughout the thermal cycle to accompany the decrease in the axial dimension of the stacks 14. The possibility of displacement of the two shafts 22, 24 along the main axis A makes it possible to compensate for the decrease in the axial dimension of the stacks 14.

[0150] Finally, during the thermal cycle, the heating elements 32 are activated to heat the internal volume of the enclosure 12 and the stacks 14 homogeneously.

[0151] The rotation of the stack of 14 layers prevents the glass from flowing due to gravity when it enters a viscoplastic state. This rotational movement also ensures homogeneous heating of the structure, eliminating the convective effects observed in vertical furnaces.

[0152] At the end of the thermal cycle, the enclosure 12 is opened by dismantling the upper half-shell 16. The elements 58 of the clamping tooling 56 are put back in place on the stacks 14 through the openings 94 of the rotating cradle 70.

[0153] The rotating cradle is then opened by dismantling the upper part 74.

[0154] The two shafts 22, 24 are then axially retracted, that is to say they are moved away from each other and from the central hub 76 allowing the stacks 14 to be separated from the shafts 22, 24.

[0155] The subassembly comprising the clamping tool 56 and the stacking assembly 14 is then removed from the internal volume of the enclosure 12. The clamping tool 56 is then removed, and the stacking 14 can then be integrated into a module.

[0156] As alternative embodiments, the enclosure and / or the rotating cradle may have a monobloc structure with a design for setting up the stacks 14 by translation along the main axis A.

[0157] According to this variant, the straight heating elements can possibly be replaced by solenoid-type heating elements.

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[0193] NOMENCLATURE: 10 installation 12 enclosure 14 stacks 16 half-shells 18 chassis 20 axial end face 22 first shaft 24 second shaft 26 axial end wall 28 motor 30 axial end wall 32 heating elements 34 radial support device 36 longitudinal bar 38 rods 40 cylindrical span 42 connecting bar 44 cylinder 46 springs 48 second shaft conduit 50 guide tooling 52 base 54 vertical arms 56 clamping tooling 58 single element 60 first end 62 second end 64 movable finger 70 rotating cradle 72 cylindrical structure 74 parts 76 central hub 78 end flanges 80 gear 82 support plate.

[0194]

[0195]

[0196]

[0197]

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[0199] 84 drive device 86 cylinder 88 linkage 90 cylinder end 92 external end 94 openings

Claims

Demands

1. Installation (10) for the production of solid oxide stacks (14), comprising: - a cylindrical enclosure (12) with main axis A in which the stacks (14) are intended to be placed coaxially with the main axis A, - a first shaft (22) and a second shaft (24) between which the stacks (14) are placed, - heating elements (32) arranged in the enclosure (12), characterized in that the main axis A of the enclosure (12) is horizontal and perpendicular to a vertical axis according to Earth's gravity, and in that the enclosure (12) comprises means for driving the stacks and the shafts (22, 24) in rotation around the main axis A.

2. 2. Installation (10) according to the preceding claim, characterized in that the drive means comprise a motor (28) coupled to the first shaft (22).

3. 3. Installation (10) according to any one of the preceding claims, characterized in that the heating elements (32) consist of a plurality of straight elements parallel to the main axis A, which are distributed around the main axis A and around the stacks (14) when the stacks are installed in the enclosure (12).

4. 4. Installation (10) according to any one of the preceding claims, in combination with claim 2 characterized in that it comprises at least one radial support device (34) which achieves centering of the stacks (14) during their rotation around the main axis A.

5. 5. Installation (10) according to the preceding claim, characterized in that the radial support device (34) comprises a longitudinal bar (36) which is movable in a radial direction relative to the main axis A and comprises drive means (44, 46) of the longitudinal bar (36) in the radial direction.

6. 6. Installation (10) according to claim 4 or 5, characterized in that the installation comprises a plurality of radial support devices (34) which are distributed around the main axis A.

7. 7. Installation (10) according to any one of the preceding claims, characterized in that at least one shaft among the first shaft (22) and the second shaft (24) is movable in axial translation along the principal axis A relative to the enclosure (12).

8. 8. Installation (10) according to claim 1, characterized in that it comprises a cradle (70) mounted for rotation inside the enclosure (12) around the main axis A and in which the stacks (14) are placed coaxially to the main axis A.

9. 9. Installation (10) according to the preceding claim, characterized in that the cradle (70) has an end flange (78) which is connected to a drive motor (28) of the cradle (70) in rotation about the main axis A.

10. 10. Installation (10) according to claim 8 or 9, characterized in that the cradle (70) comprises a central hub (76) on either side of which the stacks (14) are arranged.

11. 11. Installation (10) according to any one of claims 8 to 10, characterized in that the two shafts (22, 24) are movable in opposite and simultaneous displacements along the main axis A.

12. 12. Installation (10) according to the preceding claim, characterized in that it comprises a linkage connecting an actuator (86) to the shafts (22, 24), which transforms a displacement of the actuator (86) into opposite and simultaneous displacements of the shafts (22, 24).

13. 13. Installation (10) according to any one of claims 8 to 12, characterized in that the cradle (70) carries a plurality of longitudinal bars (36) intended to bear against the stacks (14).

14. 14. Installation (10) according to any one of the preceding claims, characterized in that it comprises a device (50) for positioning stacks (14) coaxially with each other in which the stacks (14) are assembled with their principal axes (B) vertical, according to Earth's gravity.

15. 15. Installation (10) according to the preceding claim, characterized in that it comprises means for clamping the stacks (14) to allow their handling before their placement in the enclosure (12).