SOC stack including integrated interconnect and spacer

Abstract

The solid oxide cell stack has an integrated interconnect and spacer formed by bending excess portions of the plate interconnect by 180 degrees to form at least the spacer portion connected to the interconnect by the bend on the top surface of the interconnect.

Description

[Technical field]

[0001] The present invention relates to a solid oxide cell (SOC) stack, in particular a solid oxide electrolysis cell (SOEC) or solid oxide fuel cell (SOFC) stack, comprising an integrated interconnect and spacer, in particular an integrated interconnect and spacer made from one component, i.e. folded sheet metal. [Background technology]

[0002] In an SOC stack having an operating temperature between 600°C and 1000°C, preferably between 600°C and 850°C, a number of cell units are assembled to form a stack and are connected to each other by interconnectors. The interconnectors act as a gas barrier to separate the anode and cathode sides of adjacent cell units, and at the same time they allow the conduction of electrical current between adjacent cells, i.e., the anode of one cell and the cathode of the next cell. Furthermore, the interconnectors are usually provided with a number of flow paths for the passage of process gases on both sides of the interconnect. To optimize the performance of the SOC stack, the range of advantageous values ​​should be maximized without unacceptable consequences on other ranges of associated unfavorable values ​​that should be minimized. Some of these values ​​are:

[0003] [Table 1]

[0004] Nearly all of the above values ​​are interrelated, meaning that changing one value will affect the others. Here are some relationships between the process gas flow properties in the cell and the above values: Process gas usage: The flow paths on the interconnect should be designed to provide equal amounts of process gas to each cell in the stack, ie, there should be no flow "shortcuts" through the stack.

[0005] Parasitic losses: The design of the process gas flow paths within the SOC stack and its cell units should seek to achieve low pressure drop per unit volume, reducing parasitic losses to the blower.

[0006] Electrical Efficiency: The interconnects conduct the electric current between the anode and cathode layers of adjacent cells, and therefore, in order to reduce the internal resistance, the electrically conductive contacts (hereinafter simply called "contacts") of the interconnects should be designed to establish good electrical contact to the electrodes (anode and cathode), and the contacts should not be anywhere apart, since in that case the current would flow through a longer distance of the electrodes, creating a higher internal resistance.

[0007] lifespan: It is desirable to maximize the lifetime of the SOC stack, i.e., in SOFC mode, it can be used to generate as much electricity as possible, and in SOEC mode, the amount of electrolysis products (e.g., H2 and / or CO) is maximized. The stack lifetime depends on a series of factors, such as the selection of interconnects and spacers, flow distribution on both process gas sides of the interconnect, evenly distributed protective coatings on the materials, operating conditions (temperature, current density, voltage, etc.), cell design and materials, and many other factors.

[0008] cost: The cost contribution of the interconnects (and spacers) can be reduced by avoiding the use of scarce materials, reducing the manufacturing time of the interconnects and spacers, minimizing part count, and minimizing material waste (the amount of material wasted during the manufacturing process).

[0009] size: The overall size of the fuel stack is reduced as the interconnect design ensures high utilization of the available cell area, the dead areas with low process gas flow rates should be reduced, and the inactive zones for sealing surfaces should be minimized.

[0010] Production time: The manufacturing time of the interconnects and spacers themselves should be minimized, and the interconnect design should also contribute to fast assembly of the entire stack. Generally, it is not necessary to design interconnects for every component, as this would increase manufacturing time.

[0011] Defect Rate The interconnect and spacer manufacturing methods and materials should allow for low interconnect defect rates (e.g., undesirable holes in the interconnect gas barrier, non-uniform material thickness or properties). Additionally, defect rates of assembled cell stacks can be reduced when the interconnect design reduces the total number of parts to be assembled and reduces the length and number of sealing surfaces.

[0012] Number of parts: In addition to minimizing errors and assembly time as previously mentioned, reduced part count reduces costs.

[0013] How the anode and cathode gas flows are distributed within the SOC stack is by having common manifolds for each of these two process gases. These manifolds can be either internal or external manifolds. The manifolds deliver the process gases to the individual layers in the SOC stack by way of flow paths to each layer. These flow paths are usually located in one layer of the repeating elements contained in the SOC stack, i.e. the spacer or interconnect.

[0014] Interconnectors and spacers made of sheet metal are typically made from two separate pieces of sheet material that are sealed together in the SOC stack. This requires sealing between the interconnect and spacer, as well as handling of separate parts during manufacturing. Furthermore, because these two separate sheet-like pieces generally have the same outer dimensions, a lot of material is wasted when most of the central material of the spacer sheet is removed (e.g., punched out).

[0015] US6492053 discloses a fuel cell stack including an interconnector and a spacer. Both the interconnector and the spacer are provided with inlet and outlet manifolds for oxygen / fuel flow. These inlet and outlet manifolds have grooves / passages on their surfaces for oxygen / fuel distribution along the anode and cathode. However, the grooves / passages of the interconnector and the spacer are not aligned with each other, and therefore their geometries cannot be combined to achieve multiple inlet points. Also, since these grooves / passages are on the surfaces of both the interconnector and the spacer, the formation of multiple inlet points is not feasible.

[0016] US2010297535 (Patent Document 2) discloses a bipolar plate for a fuel cell with flow channels. The flow plate has a number of channels for uniformly distributing fluids between the active areas of the fuel cell. This document does not disclose a second layer and similar flow channels therein.

[0017] US2005016729 (Patent Document 3) discloses ceramic fuel cell(s) supported in thermally conductive interconnect plates, the plates forming a conductive heater called a stack. The connection of the stacks forms a fuel cell stick. The sticks are connected end to end to form a fuel cell string. The string can be a thousand feet or more in length and is made long enough to penetrate into underground resource layers, such as oil reservoirs. A preheater brings the string to an operating temperature of over 700°C, and the fuel cell then maintains the temperature through conduits that supply fuel and oxidant to the fuel cell and carry the exhaust gas to the planetary surface. A manifold can be used between the string and the planetary surface to extend the conduits and act as a heat exchanger between the exhaust gas and the oxidant / fuel.

[0018] None of the above known techniques provide a simple, effective and reliable solution to the above problems. [Prior art documents] [Patent documents]

[0019] [Patent Document 1] US6492053 [Patent Document 2] US2010297535 [Patent Document 3] US2005016729 Summary of the Invention [Problem to be solved by the invention]

[0020] Therefore, in conjunction with the above considerations, there is a need for a multi-channel interconnect and spacer solution for SOC stacks that is robust, simple, inexpensive and easy to manufacture and handle.

[0021] These and other objectives are accomplished by the invention described below. [Means for solving the problem]

[0022] The present invention produces a single part (combining the functions of interconnector and spacer) in the form of sheet metal by folding the spacer part from an IC sheet onto one side of the sheet metal. Folding (or bending) is a mass-conserving process and therefore no waste is generated. When folding thin sheet material as in the present case, the folding radius depends on the sheet thickness and very small folding radii can be obtained.

[0023] By folding the spacer away from the interconnect sheet metal, several problems are eliminated: - The sealing area in the stack is reduced, therefore there are fewer places where leaks can occur while saving sealing layers per interconnect-spacer assembly. - Fewer parts to handle during manufacturing. - Because the spacers are manufactured from the same sheet metal as the interconnects, the thickness of the interconnects and spacers is the same, thereby reducing tolerance issues in stack assembly. If the spacer were manufactured from a separate sheet metal, it would use more material than the sealing area that is usually located at the periphery of the interconnect. Therefore, this folding solution saves material, since the folded part is included at the periphery of the interconnect and the "inside" of the spacer is used for the interconnect. The same material of the interconnects and spacers and the absence of sealing material provide the same thermal expansion coefficient. - Because the spacer is part of the interconnect, alignment of a separate spacer part is eliminated. The folding process is inexpensive and can be scaled industrially. To manufacture the integrated interconnect and spacer, the interconnect geometry is expanded to include a spacer that is then folded against the top surface of the interconnect. The folding process is simple and robust and is used in several industries (e.g., metal cans).

[0024] The thickness of the spacer is the same as the thickness of the interconnect. This reduces the tolerances when assembling the stack. This same tolerance cannot be achieved with other processes, i.e. etching of the seal between the interconnect and the spacer is omitted. This saves on part handling, since the interconnect and the spacer are one part. The spacers are usually placed on the periphery of the interconnect, so the center is cut out and discarded using standard methods. If the spacer is part of the interconnect, the inside of the spacer is not discarded, reducing the amount of material waste.

[0025] The invention as claimed in claim 1 is a solid oxide cell stack including a plurality of stacked cell units. Each of the cell units includes a cell layer with an anode, a cathode and an electrolyte, and an interconnector layer. These layers are stacked in an alternating manner such that one interconnector layer separates one cell layer from an adjacent cell layer in the cell stack. The interconnector layer does not include a separate spacer as known in the prior art, but includes an integrated interconnector and spacer manufactured from a single plate of thickness T. The spacer is formed by folding at least a part of the edge of the interconnector 180° a number N to provide a spacer covering at least a part of the edge of the interconnector. It is understood that the folding is 180° with the tolerances inherent and normal to this folding manufacturing process (which may also include some curling). It is also understood that the plate piece to be folded before folding has a larger dimension than the final integrated interconnector and spacer, with the excess area to be folded and forming the spacer after folding. After folding, the spacer and interconnector together form at least some edges of the integrated interconnector and spacer with a thickness of not more than (1+N) times the thickness T of the plate. It is understood that the thickness depends on the material and manufacturing tolerances that may result in dimensions slightly more than or slightly less than the exact thickness of not more than (1+N) times the thickness T of the plate and therefore within the scope of the claims. However, it is part of the invention that the folding process may also provide higher precision than known from conventional solid oxide cell stacks, because the gasket between the spacer and interconnector is omitted and because the folding process may be followed by a precision pressing operation that flattens the thickness of the integrated interconnector and spacer to a precise tolerance. It is understood that the contact between the cells by the integrated interconnector and spacer is ensured by both the folded edges and the contact points on the entire surface of the integrated interconnector and spacer.These contact points may be provided by contact enabling elements provided on the interconnect on the same side as the fold, which may be in the form of nets, by pressed contact points or by any other known technique.

[0026] In one particular embodiment of the invention, at least some of the edges of the interconnects are folded 180° once to provide interconnects and spacers with a thickness less than or equal to twice the thickness T of the plates.

[0027] When folded, the integrated interconnect and spacer can form at least one flow distributor for manifolds, i.e. for the inflow and outflow of process gases to the stack from a part of the edge of the interconnect, called the external manifold, and from the flow passages located inside the interconnect, called the internal manifold. The edges to be folded can be formed and they can have gaps that allow the process gases to flow through the stack, and the flow path can be oriented by the shape of the edges forming the flow distributor. These edges can be formed, for example, as pins, wedges or any other shape adapted to allow the flow and guidance of the process. This can be used for both internal and external manifolds as known in the art.

[0028] The spacer may also be formed, at least in part, by adjacent liquid-tight edges that may be adapted to form a liquid-tight seal to an external manifold or around an internal manifold. Besides the folding itself, the spacer may be further connected to an interconnect at at least a portion of the edge or surface of the spacer by diffusion bonding (a process in which atoms of two solid metal surfaces diffuse together over time), welding or other suitable connection technique.

[0029] In one aspect of the invention, the folding is facilitated and guided by grooves on one, the other or both sides of the interconnect at least a portion of the folding line. The grooves may be present on at least one side of the interconnect to shape the flow fields of the process streams. The grooves may be formed, for example, by etching.

[0030] In one particular aspect of the invention, the stack is a solid oxide electrolysis cell stack having an operating temperature as previously described. In yet another aspect of the invention, the stack is a solid oxide fuel cell stack. The sheet metal used to fabricate the integrated interconnects and spacers can be austenitic steel, ferritic steel, or any alloy suitable for the stack.

[0031] In one aspect of the invention, the solid oxide cell stack described above is manufactured by steps including providing a single plate having a thickness T and an area larger than the interconnect layer. At least some of the edges of the plate are folded 180° a number N to form a spacer. The spacer and interconnect are formed from the single plate together with at least some edges of the integrated interconnect and spacer having a thickness less than or equal to (1+N) times the thickness T of the plate.

[0032] In one specific embodiment, the plate is folded only once, so that the spacer and the interconnector together form at least some edges of the integrated interconnector and spacer with a thickness less than or equal to twice the thickness T of the plate. A further step may include a calibration of the thickness of the integrated interconnector and spacer, which allows to minimize the tolerance even further than the (double) tolerance of the plate itself. This is done by pressing the integrated interconnector and spacer to a predetermined stop value set less than (1+N) times T. The pressing force is set to a value greater than the force of plastic deformation of the integrated interconnector and spacer (permanent deformation that occurs when a material is subjected to a compressive stress, e.g., beyond its yield strength, and then compressed, e.g.).

[0033] Features of the invention 1. A solid oxide cell stack comprising a plurality of stacked cell units, each cell unit comprising a cell layer and an interconnect layer, with one interconnect layer isolating one cell layer from an adjacent cell layer within the cell stack, wherein the interconnect layer comprises an integrated interconnect and spacer fabricated from a single plate of thickness T, the spacer being formed by at least a portion of an edge of the interconnect being folded 180° a number N, thereby providing a spacer covering at least a portion of the edge of the interconnect such that the spacer and interconnect together form at least a portion of the edge of the integrated interconnect and spacer with a thickness of less than or equal to (1+N) times the thickness T of the plate.

[0034] 2. The solid oxide cell stack of feature 1, wherein the at least a portion of the edge of the interconnect is folded 180 degrees once to provide a spacer covering at least a portion of the edge of the interconnect, such that the spacer and interconnect together form at least a portion of the edge of the integrated interconnect and spacer with a thickness of less than or equal to twice the thickness T of the plates.

[0035] 3. A solid oxide cell stack according to any one of the preceding features, wherein a spacer of the integrated interconnect and spacer further forms at least one flow distributor for a manifold.

[0036] 4. A solid oxide cell stack according to any one of the preceding features, wherein a spacer of the integrated interconnect and spacer further forms at least one flow distributor adapted for an external manifold.

[0037] 5. A solid oxide cell stack according to any one of the preceding features, wherein a spacer of the integrated interconnect and spacer further defines at least one flow distributor adapted for an internal manifold.

[0038] 6. The solid oxide cell stack of any one of the preceding features, wherein a spacer of the integrated interconnect and spacer is at least partially formed by a pin.

[0039] 7. A solid oxide cell stack according to any one of the preceding features, wherein the spacers of the integrated interconnect and spacer are at least partially formed by pins formed as wedge shapes that are flow guides for the flow of process fluids.

[0040] 8. The solid oxide cell stack of any one of the preceding features, wherein a spacer of the integrated interconnect and spacer is at least partially formed by adjacent liquid-tight edges.

[0041] 9. A solid oxide cell stack according to any one of the preceding features, wherein the spacer of the integrated interconnect and spacer is at least partially formed by adjacent fluid-tight edges adapted to form a fluid-tight seal against an external manifold.

[0042] 10. A solid oxide cell stack according to any one of the preceding features, wherein the spacer of the integrated interconnect and spacer is at least partially formed by adjacent fluid-tight edges adapted to form a fluid-tight seal around an internal manifold.

[0043] 11. A solid oxide cell stack according to any one of the preceding features, wherein the spacer is not only connected to the interconnect by a folded portion but also at least one further edge or surface of the spacer facing the interconnect.

[0044] 12. The solid oxide cell stack of any one of the preceding features, wherein the spacers are connected by diffusion bonding on at least a portion of the surface of the spacers facing the interconnect.

[0045] 13. The solid oxide cell stack of any one of the preceding features, wherein the spacer is connected to the interconnect by welding on at least a portion of the spacer surface facing the interconnect.

[0046] 14. The solid oxide cell stack of any one of the previous features, wherein the interconnect has a groove on at least one surface thereof adapted to facilitate and guide said 180° fold.

[0047] 15. A solid oxide cell stack according to any one of the previous features, wherein the interconnect has grooves on at least one surface thereof adapted to form flow fields for the process fluids.

[0048] 16. A solid oxide cell stack according to any one of the previous features, wherein the interconnect has grooves etched on at least one surface thereof to form flow fields for the process fluids.

[0049] 17. A solid oxide cell stack according to any one of the preceding features, which is a solid oxide electrolysis cell stack.

[0050] 18. A method of manufacturing a solid oxide cell stack according to any one of the preceding features, comprising a plurality of stacked cell units, each cell unit comprising a cell layer and an interconnect layer, an interconnect layer separating a cell layer from an adjacent cell layer in the cell stack, and the interconnect layer comprising an integrated interconnect and spacer fabricated from a single plate, comprising the steps of: Providing a piece of plate having a thickness T and an area greater than the area of ​​the interconnect layer, forming the spacer by folding at least a portion of the edge of the plate 180° a number N times such that the spacer and the interconnect have a thickness of less than or equal to (1+N) times the thickness T of the plate and together form at least a portion of the edge of the integrated interconnect and spacer; The method comprising:

[0051] 19. The method of claim 18, wherein the at least a portion of the edges of the plates are folded once so that the spacer and interconnector together form at least a portion of the edges of the integrated interconnector and spacer with a thickness of less than or equal to twice the thickness T of the plates.

[0052] 20. A method for manufacturing a solid oxide cell stack according to any one of claims 18 to 19, further comprising the steps of: performing a calibration press on the integrated interconnect and spacer with a force greater than the plastic deformation force up to a predefined stop value in order to establish a uniform thickness of the edges of the integrated interconnect and spacer; The method comprising:

[0053] 21. A method for manufacturing a solid oxide cell stack according to any one of the above features 18 to 20, further comprising the steps of: performing a calibration press on the integrated interconnect and spacer with a force greater than the plastic deformation force up to a predetermined stop value to establish a uniform thickness of the edge of the integrated interconnect and spacer, the uniform thickness being less than (1+N) times the thickness T; The method comprising:

[0054] 22. A method for manufacturing a solid oxide cell stack according to any one of the preceding features 18 to 21, further comprising the following preceding steps: providing on at least one face of said plate a groove adapted to facilitate and guide said 180° folding, The method comprising:

[0055] 23. A method for manufacturing a solid oxide cell stack according to claim 22, wherein the grooves are formed by etching.

[0056] 24. A method for manufacturing a solid oxide cell stack according to any one of the above features 18 to 23, further comprising the steps of: Etching at least one surface of the integrated interconnect and spacer before or after folding to form flow fields for process fluids; The method comprising:

[0057] 25. A method for manufacturing a solid oxide cell stack according to any one of features 18 to 24, further comprising the step of diffusion bonding the spacer to the interconnect on at least a portion of a surface of the spacer facing the interconnect.

[0058] 26. A method for manufacturing a solid oxide cell stack according to any one of features 18 to 25, further comprising the step of welding the spacer to the interconnect on at least a portion of a surface of the spacer facing the interconnect.

[0059] The present invention is further illustrated by the accompanying drawings, which show examples of embodiments of the invention. [Brief description of the drawings]

[0060] [Figure 1] FIG. 1 shows an isometric top view of an integrated interconnect and spacer prior to folding. [Diagram 2] FIG. 2 shows an isometric top view of the integrated interconnect and spacer of FIG. 1, but now with the spacer (excess) portion of the interconnect folded over the top surface of the interconnect. [Diagram 3] FIG. 3 shows an isometric bottom view of the integrated interconnect and spacer of FIG. [Figure 4] FIG. 4 shows an enlarged isometric top view of a central portion of the integrated interconnect and spacer of FIG. [Explanation of symbols]

[0061] 1. Integrated interconnect and spacer 2. Spacer 3. Flow distributor adapted for external manifolds 4. Flow distributor adapted for internal manifolds 5. Pin 6. Adjacent liquid-tight edges DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] FIG. 1 shows an integrated interconnect and spacer 01 for a solid oxide cell stack (not shown). FIG. 1 shows the interconnect as one flat piece of sheet metal with excess material adapted to form spacers 02, but before folding, so the spacers have not yet been formed. This shape of the six sided integrated interconnect and spacer is chosen only as an example. As can be seen, part of the spacer is in the form of pins 05, which will be described in more detail below.

[0063] In FIG. 2, the excess material of the interconnect shown in FIG. 1 is now folded 180° on the top side of the interconnect to form spacers around the three edges of the interconnect as well as around the two through holes in the interconnect. Along these three edges as well as around the central through hole of the interconnect, the spacers are formed as pins to allow the process gas to flow between the spacer pins. Thus, along these three edges, the pin-shaped spacers form flow distributors adapted for the external manifolds 03; on the other hand, around the central through hole of the interconnect, the pin-shaped spacers form flow distributors adapted for the internal manifolds 04. These spacers adapted for the manifolds may be formed in various shapes to control and guide the product gas flow to, along and from the interconnect. One spacer in FIG. 2 is formed with adjacent liquid-tight edges 06, which when folded form edges around the peripheral through holes of the interconnect, thereby serving as product gas flow paths to the inside of the stack. FIG. 3 shows the same folded integrated interconnect and spacer as shown in FIG. 2, only viewed from the opposite (bottom) side of the interconnect.

[0064] The folded pins, which act as flow distributors adapted for the internal manifold around the central through hole of the interconnect, are shown in more detail in Figure 4. It should be understood that in one embodiment (not shown), the guidance and tolerance of the folded pins can be enhanced by grooves in the folded sections on one side of the sheet metal, the other side, or both sides. Also, the folded spacers can have any other shape and can be shapes other than pins, such as hole edge shapes or wedge shapes.

Claims

1. A solid oxide cell stack comprising a plurality of stacked cell units, each cell unit comprising a cell layer and an interconnect layer, with one interconnect layer isolating one cell layer from an adjacent cell layer within the cell stack, wherein the interconnect layer comprises an integrated interconnect and spacer fabricated from a single plate of thickness T, the spacer being formed by at least a portion of an edge of the interconnect being folded 180° a number N, thereby providing a spacer covering at least a portion of the edge of the interconnect, such that the spacer and interconnect together form at least a portion of the edge of the integrated interconnect and spacer with a thickness of less than or equal to (1+N) times the thickness T of the plate.

2. 2. The solid oxide cell stack of claim 1, wherein the at least a portion of an edge of the interconnect is folded once 180 degrees to provide a spacer covering at least a portion of an edge of the interconnect such that the spacer and interconnect together form an edge of at least a portion of the integrated interconnect and spacer with a thickness of no more than twice the thickness T of the plate.

3. 3. The solid oxide cell stack of claim 1 or 2, wherein a spacer of the integrated interconnect and spacer further forms at least one flow distributor for a manifold.

4. 4. The solid oxide cell stack of claim 1, wherein the spacer of the integrated interconnect and spacer further defines at least one flow distributor adapted for an external manifold.

5. 5. The solid oxide cell stack of claim 1, wherein a spacer of the integrated interconnect and spacer further defines at least one flow distributor adapted for an internal manifold.

6. The solid oxide cell stack of any one of claims 1 to 5, wherein a spacer of the integrated interconnect and spacer is at least partially formed by a pin.

7. 7. The solid oxide cell stack of claim 1, wherein the spacers of the integrated interconnect and spacer are at least partially formed by pins formed as wedge shapes that are flow guides for the flow of process fluids.

8. The solid oxide cell stack of any one of claims 1 to 7, wherein the spacer of the integrated interconnect and spacer is at least partially formed by adjacent liquid-tight edges.

9. 9. The solid oxide cell stack of claim 1, wherein the spacer of the integrated interconnect and spacer is at least partially formed by adjacent fluid-tight edges adapted to form a fluid-tight seal with an external manifold.

10. 10. The solid oxide cell stack of claim 1, wherein the spacer of the integrated interconnect and spacer is at least partially formed by adjacent fluid-tight edges adapted to form a fluid-tight seal around an internal manifold.

11. 11. The solid oxide cell stack of claim 1, wherein the spacer is not only connected to the interconnect by the folded portion but also at least one further edge or surface of the spacer facing the interconnect.

12. The solid oxide cell stack according to any one of claims 1 to 11, wherein the spacers are connected by diffusion bonding on at least a portion of the surface of the spacers facing the interconnect.

13. The solid oxide cell stack according to any one of claims 1 to 12, wherein the spacers are connected to the interconnects by welding on at least a portion of the surface of the spacers facing the interconnects.

14. The solid oxide cell stack of any one of claims 1 to 13, wherein the interconnect has a groove on at least one surface thereof adapted to facilitate and guide said 180° fold.

15. A solid oxide cell stack according to any one of claims 1 to 14, wherein the interconnect has grooves on at least one surface thereof adapted to create flow fields for the process fluids.

16. The solid oxide cell stack of any one of claims 1 to 15, wherein the interconnect has grooves etched on at least one surface thereof to form flow fields for the process fluids.

17. The solid oxide cell stack according to any one of claims 1 to 16, which is a solid oxide electrolysis cell stack.

18. 18. A method for manufacturing a solid oxide cell stack according to any one of claims 1 to 17, comprising a plurality of stacked cell units, each cell unit comprising a cell layer and an interconnect layer, an interconnect layer separating one cell layer from an adjacent cell layer in the cell stack, and the interconnect layer comprising an integrated interconnect and spacer fabricated from a single plate, comprising the steps of: - providing a piece of plate having a thickness T and an area greater than the area of ​​the interconnect layer; - forming the spacer by folding at least some of the edges of the plate 180° a number N times such that the spacer and interconnect have a thickness of less than or equal to (1+N) times the thickness T of the plate and together form at least some edges of the integrated interconnect and spacer; The method comprising:

19. 20. The method of claim 18, wherein at least a portion of the edges of the plates are folded once so that the spacers and interconnects together form at least a portion of the edges of the integrated interconnects and spacers with a thickness less than or equal to twice the thickness T of the plates.

20. 20. A method for manufacturing a solid oxide cell stack according to claim 18 or 19, further comprising the steps of: - performing a calibration press on the integrated interconnect and spacer with a force greater than the plastic deformation force up to a predefined stop value in order to establish a uniform thickness of the edges of the integrated interconnect and spacer; The method comprising:

21. A method for manufacturing a solid oxide cell stack according to any one of claims 18 to 20, further comprising the steps of: - performing a calibration press on the integrated interconnect and spacer with a force greater than the plastic deformation force up to a predetermined stop value to establish a uniform thickness of the edges of the integrated interconnect and spacer, the uniform thickness being less than (1+N) times the thickness T; The method comprising:

22. A method for manufacturing a solid oxide cell stack according to any one of claims 18 to 21, further comprising the following preceding steps: - providing a groove on at least one face of said plate adapted to facilitate and guide said 180° fold; The method comprising:

23. 23. The method of manufacturing a solid oxide cell stack according to claim 22, wherein the grooves are formed by etching.

24. A method for manufacturing a solid oxide cell stack according to any one of claims 18 to 23, further comprising the steps of: - Etching at least one surface of the integrated interconnect and spacer, before or after folding, to form flow fields for process fluids; The method comprising:

25. 25. A method for manufacturing a solid oxide cell stack according to any one of claims 18 to 24, further comprising the step of diffusion bonding the spacer to the interconnect on at least a portion of a surface of the spacer facing the interconnect.

26. 26. A method for manufacturing a solid oxide cell stack according to any one of claims 18 to 25, further comprising the step of welding the spacer to the interconnect on at least a portion of a surface of the spacer facing the interconnect.

Images