Electrochemical cell stack including multi-diameter mesh contact layer

Abstract

To improve electrical contact between a fuel electrode or an air electrode and an interconnect.SOLUTION: An electrochemical cell stack includes: at least two electrochemical cells that each include a fuel electrode, an air electrode, and an electrolyte located between the fuel electrode and the air electrode; at least one interconnect that is located between the at least two electrochemical cells; and a contact layer 400 that electrically connects the at least one interconnect and the fuel electrode of an adjacent one of the at least two electrochemical cells. The contact layer includes first wires 402 that extend in a first direction, the first wires including thinner first wires 402A and thicker first wires 402B, the thicker first wires having a thickness that is larger than a thickness of the thinner first wires, and second wires 404 that extend in a second direction different from the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Aspects of the present disclosure relate generally to electrochemical cell stacks, and more particularly to stacks of fuel or electrolyzer cells that include a mesh contact layer that includes interwoven first and second wires having different diameters. [Background technology]

[0002] A typical electrochemical cell stack, such as a stack of fuel cells or electrolyzer cells, includes multiple fuel cells separated by conductive interconnects (ICs), which provide both electrical connection between adjacent cells in the stack and channels for the delivery and removal of fuel and oxidant. Summary of the Invention

[0003] According to various embodiments, an electrochemical cell stack includes at least two electrochemical cells, each including an anode, a cathode, and an electrolyte located between the anode and the cathode, at least one interconnect located between the at least two electrochemical cells, and a contact layer electrically connecting the at least one interconnect to the anode of an adjacent one of the at least two electrochemical cells, the contact layer including first wires extending in a first direction, the first wires including a thinner first wire and a thicker first wire, the thicker first wire having a thickness greater than that of the thinner first wire, and a second wire extending in a second direction different from the first direction.

[0004] According to various embodiments, an electrochemical cell stack includes at least two electrochemical cells, each including an anode, a cathode, and an electrolyte located between the anode and the cathode, at least one interconnect located between the at least two electrochemical cells, and a contact layer electrically connecting the at least one interconnect to the anode of an adjacent one of the at least two electrochemical cells, the contact layer including a first wire extending in a first direction, the first wire comprising a first material having a first hardness, and a second wire extending in a second direction different from the first direction, the second wire comprising a second material having a second hardness lower than the first hardness.

[0005] According to various embodiments, an electrochemical cell stack includes at least two electrochemical cells, each including an anode, a cathode, and an electrolyte located between the anode and the cathode, at least one interconnect located between the at least two electrochemical cells, and a contact layer electrically connecting the at least one interconnect to the anode of an adjacent one of the at least two electrochemical cells, the contact layer including first wires extending in a first direction, the first wires having a first wire density, and second wires extending in a second direction different from the first direction, the second wires having a second wire density different from the first wire density.

[0006] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

[0007] The accompanying drawings, which are included to provide a further understanding of the invention, and which are incorporated into and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1A is a perspective view of an electrochemical cell stack according to various embodiments of the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view of a portion of the stack of FIG. 1A. [Figure 2A] FIG. 2A is a top view of the air side of an interconnect according to various embodiments of the present disclosure. [Figure 2B] FIG. 2B is a top view of the fuel side of the interconnect of FIG. 2A. [Figure 3A] FIG. 3A is a three-dimensional view of an electrochemical cell column according to various embodiments of the present disclosure. [Figure 3B] FIG. 3B is a vertical cross-sectional view of a portion of the column of FIG. 3A. [Figure 3C-J] 3C-J are perspective views of various weaves that may be used in the mesh contact layer of embodiments of the present disclosure. [Figure 4] FIG. 4 is a top view of an interface layer according to one embodiment of the present disclosure. [Figure 5] FIG. 5 is a top view of an alternative interface layer according to an alternative embodiment of the present disclosure. [Figure 6] FIG. 6 is a top view of an alternative interface layer according to an alternative embodiment of the present disclosure. [Figure 7] FIG. 7 is a top view of an alternative interface layer according to an alternative embodiment of the present disclosure. [Figure 8] FIG. 8 is a top view of an alternative interface layer according to an alternative embodiment of the present disclosure. [Figure 9] FIG. 9 is a top view of an alternative interface layer according to an alternative embodiment of the present disclosure. [Figure 10] FIG. 10 is a top view of an alternative interface layer according to an alternative embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Various embodiments will be described in detail with reference to the accompanying drawings. The drawings, which are not necessarily to scale, are intended to illustrate various features of the invention. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. References to specific examples and implementations are made for illustrative purposes and are not intended to limit the scope of the invention or the claims.

[0010] Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such ranges are expressed, they include, by way of example, from one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the prefix "about" or "substantially," it will be understood that the particular value forms another dimension. In some embodiments, a value "about X" may include the value + / - 1% X. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0011] Electrochemical cell systems include fuel cell and electrolyzer cell systems. In high-temperature fuel cell systems, such as solid oxide fuel cell (SOFC) systems, an oxidizing stream is directed to the cathode side of the fuel cell and a fuel stream is directed to the anode side of the fuel cell. The oxidizing stream is typically air, and the fuel stream can be hydrogen (H2), or a hydrocarbon fuel such as methane, natural gas, ethanol, or methanol, or a hydrogen-containing fuel such as ammonia. When the fuel cell operates at typical temperatures between 750°C and 950°C, negatively charged oxygen ions can be transferred from the cathode flow stream to the anode flow stream, where they combine with free hydrogen or hydrogen in hydrocarbon molecules to form water vapor and / or with carbon monoxide to form carbon dioxide. Excess electrons from the negatively charged ions are directed back to the cathode side of the fuel cell through the completed electrical circuit between the anode and cathode, resulting in the flow of electrical current through the circuit. In electrolyzer systems, such as solid oxide electrolyzer systems, water (eg, steam) is separated into hydrogen and oxygen by applying a voltage across the electrolyzer cells.

[0012] 1A is a perspective view of an electrochemical cell stack 100 according to various embodiments of the present disclosure, and FIG. 1B is a cross-sectional view of a portion of the stack 100. However, it should be noted that the stack 100 can also be operated as an electrolyzer cell stack (e.g., a solid oxide electrolyzer cell (SOEC) stack). In an SOEC stack, the anode is the cathode and the cathode is the anode. Thus, in both SOFC and SOEC cells, the electrode to which fuel (e.g., hydrogen or hydrocarbon fuel in an SOFC and water / steam in an SOEC) is supplied may be referred to as the anode, and the opposite electrode may be referred to as the cathode.

[0013] 1A and 1B, stack 100 includes electrochemical cells (e.g., fuel cells or electrolyzer cells) 30 separated by interconnects 10. Referring to FIG. 1B, each cell 30 includes a cathode 33, a solid oxide electrolyte 35, and an anode 37.

[0014] Various materials may be used for the cathode 33, electrolyte 35, and anode 37. For example, the anode 37 of an SOFC or SOEC may include a cermet containing a nickel-containing phase and a ceramic phase. The nickel-containing phase may consist solely of nickel in a reduced state. This phase may form nickel oxide when oxidized. Thus, the anode 37 is preferably annealed in a reducing atmosphere prior to operation to reduce the nickel oxide to nickel. The nickel-containing phase may include other metals in addition to nickel and / or nickel alloys. The ceramic phase may include stabilized zirconia, such as yttria- and / or scandia-stabilized zirconia, and / or doped ceria, such as gadolinia-, yttria-, and / or samaria-doped ceria.

[0015] The electrolyte 35 of the SOFC or SOEC may include scandia-stabilized zirconia (SSZ), yttria-stabilized zirconia (YSZ), yttria-ceria-stabilized zirconia (YCSZ), ytterbia-ceria-scandia-stabilized zirconia (YbCSSZ), or hybrids thereof. In YbCSSZ, as disclosed in U.S. Pat. No. 8,580,456, incorporated herein by reference, scandia may be present in an amount equal to 9 mol% to 11 mol%, e.g., 10 mol%, ceria may be present in an amount greater than 0 mol% and less than or equal to 3 mol%, e.g., 0.5 mol% to 2.5 mol%, e.g., 1 mol%, and ytterbia may be present in an amount greater than 0 mol% and less than or equal to 2.5 mol%, e.g., 0.5 mol% to 2 mol%, e.g., 1 mol%. Alternatively, the electrolyte 35 may include another ion-conducting material, such as doped ceria.

[0016] The cathode 33 of the SOFC or SOEC may include a conductive material, such as a conductive perovskite material, such as lanthanum strontium manganite (LSM). Other conductive perovskites, such as lanthanum strontium cobaltate, or metals, such as Pt, may also be used. The cathode 33 may also include a ceramic phase similar to the anode 37. The electrodes and electrolyte may each include one or more sublayers of the materials described above.

[0017] An electrochemical cell stack 100 is often constructed from multiple electrochemical cells 30, which may take the form of planar elements, tubes, or other geometric shapes. While the stack in FIG. 1A is oriented vertically, the stack may be oriented horizontally or in other orientations. Fuel and air may be provided to the electrochemically active surfaces of the fuel cells 30. For example, fuel may be provided through fuel holes 20 formed in each interconnect 10. The fuel holes 20 may be aligned to form a fuel conduit (i.e., a fuel riser channel) extending through the stack 100.

[0018] Each interconnect 10 electrically connects adjacent cells 30 in the stack 100. In particular, an interconnect 10 can electrically connect the anode 37 of one cell 30 to the cathode 33 of an adjacent cell 30. Figure 1B shows that the bottom cell 30 is located between two interconnects 10.

[0019] Each interconnect 10 includes fuel ribs 12A that at least partially define fuel channels 8A and air ribs 12B that at least partially define oxidant (e.g., air) channels 8B. The interconnects 10 can operate as gas-fuel separators, separating fuel flowing to the anode 37 of one cell in the stack from oxidant, such as air, flowing to the cathode 33 of an adjacent cell in the stack.

[0020] Each interconnect 10 may be made of or include a conductive material, such as a metal alloy (e.g., a chromium-iron alloy) having a thermal expansion coefficient similar to that of the solid oxide electrolyte in the cell 30 (e.g., a difference of 0% to 10%). For example, the interconnect 10 may include a metal (e.g., a chromium-iron alloy, such as 4 to 6 weight percent iron, optionally up to 1 weight percent yttrium, and the balance chromium). A conductive contact layer 11, which may be formed of a conductive material such as lanthanum strontium manganite (LSM) and / or spinel manganese cobalt oxide (MCO), may be provided on the air side of each interconnect 10.

[0021] FIG. 2A is a top view of the air side of an exemplary interconnect 10, and FIG. 2B is a top view of the fuel side of the interconnect 10, according to one embodiment of the present disclosure. Referring to FIGS. 1B and 2A, the air side includes air channels 8B located between air ribs 12B. Air flows through the air channels 8B to the cathode 33 of an adjacent cell 30. The interconnect 10 may include a ring seal area 14 and a strip seal area 16. The seal areas 14, 16 may be flat surfaces that are flush with the tops of the air ribs 12B. Fuel holes 20 may be formed in the ring seal area 14 or may extend through the interconnect 10. A ring seal 22 may be disposed in the ring seal area 14 surrounding the fuel hole 20 to prevent fuel from contacting the adjacent cathode 33. A strip seal 24 may be disposed in the strip seal area 16. The seals 22, 24 may be formed of glass or glass-ceramic materials. The strip seal area 16 may be a raised platform that does not include ribs or channels.

[0022] In some embodiments, a corrosion barrier layer (CBL) 13 (FIG. 2A) may be formed between the contact layer 11 (FIG. 1B) and the ring seal 22. The CBL 13 may be formed of a glass-ceramic composite configured to limit the diffusion of manganese and / or manganese species from the contact layer 11 into an adjacent glass seal, such as the ring seal 22. The CBL 13 may include a crystalline phase dispersed in a glassy (e.g., amorphous) matrix phase. In some embodiments, the crystalline phase may include zirconium silicate (ZrSiO) crystals and / or magnesium aluminosilicate crystals, such as barium magnesium aluminosilicate crystals or barium-free magnesium aluminosilicate crystals. The crystalline phase may further include calcium silicate crystals, such as calcium magnesium silicate crystals, calcium aluminosilicate crystals, and / or magnesium-free and aluminum-free calcium silicate crystals.

[0023] 1B and 2B, the fuel side of the interconnect 10 may include a fuel channel 8A located between the fuel ribs 12A and a fuel manifold 28 surrounded by a frame seal area 18. The frame seal area 18 may be a flat area flush with the tops of the fuel ribs 12A. Fuel flows from one of the fuel holes 20 (e.g., an inlet hole forming part of a fuel inlet riser) into the adjacent manifold 28, through the fuel channel 8A, and to the anode 37 of the adjacent fuel cell 30. Excess fuel may flow into the other fuel manifold 28 and then into the other (e.g., outlet) fuel hole 20. A frame seal 26 may be disposed in the frame seal area 18. The frame seal 26 may be formed of a glass or glass-ceramic material.

[0024] FIG. 3A is a perspective view of a fuel cell column 300 according to various embodiments of the present disclosure, and FIG. 3B is an exploded cross-sectional view of a portion of the fuel cell column 300.

[0025] 3A and 3B, a fuel cell column 300 may include one or more electrochemical cell stacks 100, an optional fuel inlet conduit 302, an optional fuel exhaust conduit 304, an end plate 306, and an optional fuel manifold 310 (e.g., an anode splitter plate). The fuel inlet conduit 302 is fluidly connected to the fuel manifolds 310 and configured to provide a fuel supply to each of the fuel manifolds 310, and the fuel exhaust conduit 304 is fluidly connected to the fuel manifolds 310 and configured to receive a fuel exhaust from each of the fuel manifolds 310.

[0026] Fuel manifolds 310 may be disposed between stacks 100 and may be configured to provide a fuel supply to and receive a fuel exhaust from stacks 100. For example, fuel manifolds 310 may be fluidly connected to internal fuel riser channels formed by aligning fuel holes 20 of interconnects 10, as discussed above and shown in FIG. 1A. In particular, fuel manifolds 310 may include fuel holes 312 vertically aligned with the riser channels / fuel holes 20 and fuel channels 314 fluidly connecting fuel holes 312 to fuel inlet conduits 302 and fuel exhaust conduits 304.

[0027] Fuel cell column 300 may also include a compression assembly 340 and side baffles 350 positioned on either side of the stacked fuel cells 100. Side baffles 350 may be formed of a ceramic material and may be connected to compression assembly 340 and underlying stack components (not shown) by ceramic connectors 352. Compression assembly 340 may be configured to apply pressure to and / or compress the column to seal adjacent components of the column.

[0028] 3B, each stack 100 may also include an air end plate 50 disposed on the air side of the stack 100 and a fuel end plate 52 disposed on the fuel end of the stack 100. In particular, the fuel end plate 52 may be disposed at the anode 37 of the outermost (e.g., uppermost or lowermost) cell 30 of the stack 100, and the air end plate 50 may be disposed at the cathode 33 of the outermost (e.g., uppermost or lowermost) cell 30 of the stack 100.

[0029] The stack 100 may also include a contact layer 40 compressed between the fuel side of each interconnect 10 and the anode 37 of the adjacent cell 30. The contact layer 40 may also be compressed between the fuel end plate 52 and the anode 37 of the adjacent cell 30. The contact layer 40 may be configured to maintain electrical contact through heat, current, and / or redox cycling. The contact layer 40 may also be configured to accommodate shape and / or thickness inconsistencies in the stack 100 under compression.

[0030] The fuel cell stacks, columns, and interconnects variously shown in Figures 1A, 1B, 2A, 2B, 3A, and 3B are exemplary implementations. Other stack and column configurations are within the scope of the present invention. For example, the contact layers of the disclosed embodiments can be used with interconnects and columns configured such as those disclosed in U.S. Patent Nos. 11,355,762, 11,705,557, and 11,870,121, all of which are incorporated herein by reference.

[0031] In each of the various stack, column, and interconnect embodiments, the contact layers 40 may each include at least one mesh of interwoven metal wires. The wires may be formed of one or more compliant conductive materials that are resistant to high temperatures and chemical reactions, such as nickel and / or nickel alloys. Suitable nickel alloys include nickel-manganese alloys such as Nickel 211 or Nickel 212, and nickel-copper alloys such as Monel 400, Monel 401, Monel 404, Monel R405, or Monel K500.

[0032] The composition ranges for the Nickel 211 and Nickel 212 alloys are shown in weight percent in Table 1 below.

[0033] [Table 1]

[0034] The composition ranges for Monel 400, Monel 401, Monel 404, Monel R405, and Monel K500 alloys are shown in weight percent in Table 2 below.

[0035] [Table 2]

[0036] In particular, the interface layer 40 may include first wires extending in a first direction and second wires extending in a second direction different from the first direction and interwoven with the first wires. In one embodiment, the first and second directions may be perpendicular to each other. In another embodiment, the first and second directions may be non-parallel and non-perpendicular to each other. For example, the first and second directions may extend at least 10 degrees and less than 90 degrees relative to each other, e.g., at least 45 degrees and less than 90 degrees relative to each other, e.g., at least 60 degrees and less than 90 degrees relative to each other. In some embodiments, the first and second directions may be different ones of the warp and weft directions of the mesh.

[0037] The contact layer 40 may be woven in any suitable weave pattern, such as a plain Dutch weave, a twill weave, a square mesh weave (also called a plain weave), a twill Dutch weave, a lock crimp weave, an inter-crimp weave, a twill Dutch double weave, or a stranded weave, as shown in Figures 3C, 3D, 3E, 3F, 3G, 3H, 3I, and 3J, respectively. The contact layer 40 may have a wire density ranging from about 25 to about 150 wires per inch, for example, from about 35 to about 100 wires per inch, or a density of about 50 wires per inch. In one embodiment, the wire density may be at least 50 wires per inch, for example, from 50 to 150 wires per inch.

[0038] For example, the contact layer 40 may have an initial (i.e., uncompressed) thickness approximately equal to the maximum combined thickness of the first and second wires. When a force is applied to compress the contact layer 40, resistance to compression is initially localized at the intersection points (e.g., nodes) of the first and second wires, resulting in deformation of the wires at the intersection points. Further compression of the contact layer involves additional force because compression is resisted by the deformed intersection points and the remaining portions of the first and second wires.

[0039] If the mesh of the interface layer 40 includes first and second wires having the same thickness, the force versus displacement / deformation curve of the interface layer may increase exponentially, resulting in an undesirably relatively steep curve. In contrast, the interface layer 40 of various embodiments may have a gentler force versus displacement / deformation curve by utilizing wires of different thicknesses and / or different materials.

[0040] In the first embodiment, the first wire may include multiple wires having different wire thicknesses. The second wire may also optionally include multiple wires having different wire thicknesses. Specifically, during compression of the interface layer 40, the nodes of the two thicker wires engage first, then as compression increases, the nodes of the thicker wire and the thinner wire engage, and finally the nodes of the two thinner wires engage. Wires of different thicknesses provide the interface layer 40 with desirable properties, such as low hysteresis, a gentle force vs. displacement / deformation curve, and multiple contact points.

[0041] In a second embodiment, the first and second wires are formed of different metals or metal alloys, which may have different hardness and / or creep characteristics. For example, the second wire may be formed of a relatively soft material, such as pure nickel, and the first wire may be formed of a harder material, such as a nickel alloy containing manganese or copper. In one aspect of the second embodiment, the second wire may comprise a denser wire (i.e., having a higher numerical density) than the first wire.

[0042] In the third embodiment, the wires may have a different thickness than in the first embodiment and a different material composition than in the second embodiment. In one aspect of the third embodiment, the contact layer 40 may include thinner wires formed of a relatively soft material, such as pure nickel, and thicker wires formed of a harder material, such as a nickel alloy containing manganese or copper. The force required to compress such a contact layer may increase more gradually compared to a mesh contact layer including wires of the same thickness and material composition. For example, a softer alloy, such as pure nickel, may be used with thinner or higher number density wires. In the plain Dutch twill weave shown in FIG. 3C, thicker wires are used in the warp direction and thinner wires are used in the weft direction, with a harder alloy, such as Ni212, used for the warp wires and a softer material, such as pure nickel, used for the weft wires.

[0043] In a fourth embodiment, the wires may have different wire densities in the warp and weft directions, and optionally the denser wires may be thinner and / or softer than the sparser wires.

[0044] 4 is a top view of an exemplary contact layer 400 that may be included in an electrochemical cell stack according to a first embodiment of the present disclosure. Referring to FIG. 4 , the contact layer 400 may include a square mesh of interwoven first wires 402 and second wires 404. The first wires 402 may extend in a first direction (e.g., may include warp wires or weft wires), and the second wires 404 may extend in a second direction substantially perpendicular to the first direction (e.g., may include the other of the warp wires or weft wires). The first wires 402 and the second wires 404 may be formed of materials independently selected from nickel, nickel alloys as discussed above, or combinations thereof, etc.

[0045] The first wires 402 may include a thinner first wire 402A and a thicker first wire 402B that is thicker than the thinner first wire 402A. The thicker first wire 402B may have a diameter larger than the diameter of the thinner first wire 402A. For example, the diameter of the thicker first wire 402B may be at least 10 microns larger than the diameter of the thinner first wire 402A, such as by about 20 μm to about 50 μm, for example, by about 30 μm to about 40 μm. In one embodiment, the thinner first wires 402A and the thicker first wires 402B may be arranged alternately in the contact layer 400.

[0046] In one embodiment, the thinner first wire 402A may have a diameter in the range of about 25 μm to about 75 μm, for example, about 35 μm to about 65 μm, or about 45 μm to about 55 μm, for example, about 50 μm. In one embodiment, the diameter of the thinner first wire 402A may be the same or approximately the same as the diameter of the second wire 404. The thicker first wire 402B may have a diameter in the range of about 50 μm to about 100 μm, for example, about 65 μm to about 95 μm, or about 75 μm to about 85 μm, for example, about 80 μm.

[0047] Thinner first wires 402A and thicker first wires 402B may reduce the amount of force required to initially compress the contact layer 400. In particular, the combination of thinner first wires 402A and thicker first wires 404B may allow a greater range of plastic deformation in the contact layer 400, allowing the contact layer 400 to accommodate a greater range of thickness changes when compressed.

[0048] In some embodiments, the thinner first wire 402A may be formed of pure nickel or a relatively soft nickel alloy, and the thicker first wire 402B may be formed of a relatively hard nickel alloy that has a higher hardness than the material of the thinner first wire 402A. The first wire 402 and second wire 404 may have the same wire density or may have different wire densities from each other.

[0049] 4, the second wires 404 may have substantially the same diameter as each other. For example, the diameter of the second wires 404 may be in the range of about 25 μm to about 75 μm, e.g., about 35 μm to about 65 μm, or about 45 μm to about 55 μm, e.g., about 50 μm. In some embodiments, the second wires 404 may be formed of pure nickel.

[0050] 5 is a top view of an alternative contact layer 500 that may be included in an electrochemical cell stack according to an alternative embodiment of the present disclosure. Contact layer 500 may be similar to contact layer 400; therefore, only the differences will be discussed in detail.

[0051] Referring to FIG. 5, the first wires 402 of the contact layer 500 may include alternating thinner first wires 402A and thicker first wires 402B as described above, and the second wires 404 of the contact layer 500 may also include alternating thinner second wires 404A and thicker second wires 404B.

[0052] The diameter of the thicker second wire 404B may be at least 10 microns greater than the diameter of the thinner second wire 404A, e.g., by about 20 μm to about 50 μm, e.g., by about 30 μm to about 40 μm. In one embodiment, the thinner second wires 404A and the thicker second wires 404B may be alternately arranged in the contact layer 500. The thinner second wires 404A may have a diameter in the range of about 25 μm to about 75 μm, e.g., about 35 μm to about 65 μm, or about 45 μm to about 55 μm, e.g., about 50 μm. The thicker second wires 404B may have a diameter in the range of about 50 μm to about 100 μm, e.g., about 65 μm to about 95 μm, or about 75 μm to about 85 μm, e.g., about 80 μm. By including thinner and thicker wires in both the first wire 402 and the second wire 404, the mechanical properties of the interface layer 500 may be further improved.

[0053] 6 is a top view of an alternative contact layer 600 that may be included in an electrochemical cell stack according to an alternative embodiment of the present disclosure. Contact layer 600 may be similar to contact layer 500; therefore, only the differences will be discussed in detail.

[0054] 6, the first wires 402 of the contact layer 600 may include alternating thinner first wires 402A, intermediate first wires 402C, and thicker first wires 402B. The intermediate first wires 402C may have a diameter that is between the diameters of the thinner first wires 402A and the diameters of the thicker first wires 402B. The diameters of the thinner first wires 402A, intermediate first wires 402C, and thicker first wires 402B may differ from one another by at least 5 microns, e.g., by about 5 μm to about 40 μm, e.g., by about 10 μm to about 20 μm.

[0055] For example, the thinner first wire 402A may have a diameter in the range of about 25 μm to about 75 μm, e.g., about 35 μm to about 65 μm, or about 45 μm to about 55 μm, e.g., about 50 μm. The thicker first wire 402B may have a diameter in the range of about 50 μm to about 100 μm, e.g., about 65 μm to about 95 μm, or about 75 μm to about 85 μm, e.g., about 80 μm. The intermediate first wire 402C may have a diameter in the range of about 40 μm to about 90 μm, e.g., about 50 μm to about 80 μm, or about 60 μm to about 70 μm, e.g., about 60 μm to about 65 μm.

[0056] The second wires 404 of the contact layer 600 may include alternating thinner second wires 404A, intermediate second wires 404C, and thicker second wires 404B. The intermediate second wires 404C may have a larger diameter than the thinner second wires 404A and a smaller diameter than the thicker second wires 404B. The diameters of the thin second wires 404A, intermediate second wires 404C, and thicker second wires 404B may differ from one another by at least 5 microns, for example, by about 5 μm to about 40 μm, for example, by about 10 μm to about 20 μm.

[0057] For example, the thinner second wire 404A may have a diameter in the range of about 25 μm to about 75 μm, e.g., about 35 μm to about 65 μm, or about 45 μm to about 55 μm, e.g., about 50 μm. The thicker second wire 404B may have a diameter in the range of about 50 μm to about 100 μm, e.g., about 65 μm to about 95 μm, or about 75 μm to about 85 μm, e.g., about 80 μm. The intermediate second wire 404C may have a diameter in the range of about 40 μm to about 90 μm, e.g., about 50 μm to about 80 μm, or about 60 μm to about 70 μm, e.g., about 60 μm to about 65 μm.

[0058] Therefore, the contact layer 600 may include first wires 402 having three different diameters and second wires 404 having three different diameters to further improve the mechanical properties of the contact layer 600.

[0059] 7 is a top view of an alternative contact layer 700 that may be included in an electrochemical cell stack according to an alternative embodiment of the present disclosure. Contact layer 700 may be similar to contact layer 600; therefore, only the differences will be discussed in detail.

[0060] 7, the first wires 402 of the contact layer 700 may include alternating thinner first wires 402A, thinner intermediate first wires 402C, thicker intermediate first wires 402D, and thicker first wires 402B. In some embodiments, the diameters of the thinner first wires 402A, thinner intermediate first wires 402C, thicker intermediate first wires 402D, and thicker first wires 402B differ from one another by at least 5 microns, e.g., by about 5 μm to about 40 μm, e.g., by about 10 μm to about 20 μm.

[0061] For example, the thinner first wire 402A may have a diameter in the range of about 25 μm to about 75 μm, e.g., about 35 μm to about 65 μm, or about 45 μm to about 55 μm, e.g., about 50 μm. The thicker first wire 402B may have a diameter in the range of about 50 μm to about 100 μm, e.g., about 65 μm to about 95 μm, or about 75 μm to about 85 μm, e.g., about 80 μm.

[0062] The thinner intermediate first wire 402C may have a larger diameter than the thinner first wire 402A and a smaller diameter than the thicker first wire 402B. For example, the thinner intermediate first wire 402C may have a diameter in the range of about 40 μm to about 80 μm, e.g., about 50 μm to about 70 μm, e.g., about 60 μm.

[0063] The thicker intermediate first wire 402D may have a larger diameter than the thinner intermediate first wire 402C and a smaller diameter than the thicker first wire 402B. For example, the thicker intermediate first wire 402D may have a diameter in the range of about 50 μm to about 80 μm, e.g., about 50 μm to about 80 μm, e.g., about 70 μm.

[0064] However, in other embodiments, the number of wires of different diameters may vary. For example, the first wire 402 and / or the second wire 404 may include wires having four or more different diameters. In other embodiments, the first wire 402 and the second wire 404 may have a different number of wire diameters. For example, the first wires 402 may all have the same diameter, and the second wire 404 may include wires of three or more different diameters. In an alternative configuration, the first wire 402 may include wires of two different diameters, and the second wire 404 may include wires of three or more different diameters.

[0065] 8 is a top view of an alternative contact layer 800 that may be included in an electrochemical cell stack according to an alternative embodiment of the present disclosure. Contact layer 800 may be similar to contact layer 400; therefore, only the differences will be discussed in detail.

[0066] The contact layer 400 described above includes first and second wires 402, 404 that extend in respective first and second directions that are perpendicular to one another (i.e., the first wire 402 extends at a 90-degree angle relative to the second wire 404). In an alternative contact layer 800, the first and second wires 402, 404 extend in respective first and second directions that are non-parallel and non-perpendicular to one another. For example, the first and second directions may extend at an angle "A" of at least 10 degrees and less than 90 degrees relative to one another, e.g., at least 45 degrees and less than 90 degrees relative to one another, e.g., at least 60 degrees and less than 90 degrees relative to one another. Thus, the first and second wires 402, 404 may be non-parallel and non-perpendicular to one another. In other alternative embodiments, the first wires 402 and second wires 404 in the contact layers 500, 600 or 700 may also be non-parallel and non-perpendicular to each other.

[0067] 9 is a top view of an alternative contact layer 900 that may be included in an electrochemical cell stack according to an alternative embodiment of the present disclosure. Contact layer 900 may be similar to contact layer 500; therefore, only the differences will be discussed in detail.

[0068] The interface layers 400, 500, 600, 700, and 800 described above include a single wire mesh having different wire thicknesses and / or different materials, with first and second wires interwoven. In contrast, the alternative interface layer 900 includes two distinct wire meshes 901 and 903, one above the other. Thus, the first wire mesh 901 includes at least a portion of a second wire 404 (e.g., a thinner second wire 404A) interwoven with a thinner first wire 402A. The second wire mesh 903 includes an additional wire (e.g., a thicker second wire 404B, or a portion of a second wire 404) interwoven with a thicker first wire 402B. The wires of the first mesh 901 are laterally offset from the wires of the second mesh 903. Additionally, the first wires 402A of the first mesh 901 may be parallel or non-parallel to the first wires 402B of the second mesh 903. Similarly, the second wires 404A of the first mesh 901 may be parallel or non-parallel to the second wires 404B of the second mesh 903. Any one of the interface layers 400, 500, 600, 700 and / or 800 described above may include two or more different wire meshes positioned on top of each other but not interwoven with each other.

[0069] 10 is a top view of an alternative contact layer 1000 that may be included in an electrochemical cell stack according to an alternative embodiment of the present disclosure. Contact layer 1000 may be similar to contact layer 400. Therefore, only the differences therebetween will be discussed in detail.

[0070] In the contact layer 1000, the first wires 402 have a first wire density and the second wires 404 have a second wire density that is different from the first density. For example, the second density may be higher than the first density. The first wire density may be in the range of about 25 to about 75 wires per inch, and the second wire density may be in the range of about 50 to about 150 wires per inch.

[0071] In one embodiment, the first wire 402 may comprise a warp wire, and the second wire 404 may comprise a weft wire. In one embodiment, the first wire 402 may have the same thickness (e.g., diameter) and material composition as the second wire 404. In another embodiment, the first wire 402 may have a different thickness (e.g., diameter) and / or a different material composition than the second wire 404. For example, the first wire 402 may be thinner and / or softer than the second wire 404.

[0072] Any one or more features from any one or more embodiments may be used with any one or more features of the other embodiments in any suitable combination. For example, interface layer 40 may include any combination of features found in interface layers 400, 500, 600, 700, 800, 900, and / or 1000. Furthermore, although a square weave is shown in Figures 4-10 for simplicity, other weaves, such as the weaves shown in Figures 3C, 3D, or 3F-3J, may alternatively be used.

[0073] While the foregoing represents particularly preferred embodiments, it will be understood that the present invention is not limited thereto. Those skilled in the art will recognize that various modifications can be made to the disclosed embodiments and that such modifications are intended to be within the scope of the present invention. All publications, patent applications, and patents cited herein are hereby incorporated by reference in their entirety.

Claims

1. 1. An electrochemical cell stack comprising: at least two electrochemical cells, each including an anode, a cathode, and an electrolyte located between the anode and the cathode; at least one interconnect located between the at least two electrochemical cells; a contact layer electrically connecting the at least one interconnect and the anode of an adjacent one of the at least two electrochemical cells, the contact layer comprising: first wires extending in a first direction, the first wires including a thinner first wire and a thicker first wire, the thicker first wire having a thickness greater than a thickness of the thinner first wire; a second wire extending in a second direction different from the first direction; a contact layer comprising: The electrochemical cell stack comprising:

2. the interface layer includes at least one wire mesh; the thicker first wire has a diameter greater than a diameter of the thinner first wire; The electrochemical cell stack of claim 1 .

3. the diameter of the second wire is in the range of about 40 μm to about 60 μm; the diameter of the thinner first wire ranges from about 40 μm to about 60 μm; the diameter of the thicker first wire ranges from about 60 μm to about 90 μm; The electrochemical cell stack of claim 2 .

4. 3. The electrochemical cell stack of claim 2, wherein the first wires further include an intermediate first wire having a diameter greater than a diameter of the thinner first wire and less than a diameter of the thicker first wire.

5. The first wire comprises: an intermediate thinner first wire having a diameter greater than the diameter of the thinner first wire and less than the diameter of the thicker first wire; a thicker intermediate first wire having a diameter greater than the diameter of the thinner intermediate first wire and less than the diameter of the thicker first wire; The electrochemical cell stack of claim 2 further comprising:

6. the thinner first wires, the thinner intermediate first wires, the thicker intermediate first wires, and the thicker first wires are arranged alternately in each contact layer; the diameter of the second wire is in the range of about 40 μm to about 60 μm; the diameter of the thinner first wire ranges from about 40 μm to about 60 μm; the diameter of the thicker first wire ranges from about 70 μm to about 90 μm; the diameter of the thinner intermediate first wire ranges from about 50 μm to about 70 μm; the diameter of the thicker intermediate first wire ranges from about 60 μm to about 80 μm; The electrochemical cell stack of claim 5 .

7. The electrochemical cell stack of claim 1 , wherein the first wire and the second wire comprise nickel, a nickel alloy, or a combination thereof.

8. 8. The electrochemical cell stack of claim 7, wherein the second wire and the thinner first wire are softer than the thicker first wire.

9. The electrochemical cell stack of claim 1 , wherein the at least two electrochemical cells comprise solid oxide fuel cells.

10. The electrochemical cell stack of claim 1 , wherein the at least two electrochemical cells comprise solid oxide electrolyzer cells.

11. 10. The electrochemical cell stack of claim 1, wherein the thicker first wires and the thinner first wires are arranged in alternating order in the contact layer.

12. 3. The electrochemical cell stack of claim 2, wherein the second wires include a thinner second wire and a thicker second wire having a diameter greater than the diameter of the thinner second wire.

13. 13. The electrochemical cell stack of claim 12, wherein the thinner first wire and the thinner second wire comprise a softer material than the thicker first wire and the thicker second wire.

14. 14. The electrochemical cell stack of claim 13, wherein the thinner first wire and the thinner second wire comprise pure nickel and the thicker first wire and the thicker second wire comprise a nickel alloy that is harder than the pure nickel.

15. the diameter of the thinner first wire ranges from about 40 μm to about 60 μm; the diameter of the thinner second wire ranges from about 40 μm to about 60 μm; the diameter of the thicker first wire ranges from about 60 μm to about 90 μm; the diameter of the thicker second wire ranges from about 60 μm to about 90 μm; The electrochemical cell stack of claim 12.

16. the first wires further include an intermediate first wire having a diameter greater than the diameter of the thinner first wire and less than the diameter of the thicker first wire; 13. The electrochemical cell stack of claim 12, wherein the second wires further include a thinner intermediate second wire having a diameter greater than a diameter of the thinner second wire and less than a diameter of the thicker second wire.

17. The electrochemical cell stack of claim 1 , wherein the second direction is perpendicular to the first direction.

18. The electrochemical cell stack of claim 1 , wherein the first direction and the second direction extend at an angle of at least 10 degrees and less than 90 degrees relative to each other.

19. an end plate located adjacent to the anode of the other of the at least two electrochemical cells; another contact layer electrically connecting the anode and the end plate of the other of the at least two electrochemical cells; The electrochemical cell stack of claim 1 further comprising:

20. 10. The electrochemical cell stack of claim 1, wherein the contact layer comprises a single wire mesh, and the second wire is interwoven with the thicker first wire and the thinner first wire in the single wire mesh.

21. 21. The electrochemical cell stack of claim 20, wherein the single wire mesh has a wire density of at least 50 wires per inch.

22. 21. The electrochemical cell stack of claim 20, wherein the first wires have a first wire density and the second wires have a second wire density different from the first wire density.

23. the interface layer includes a first wire mesh and a second wire mesh; the first wire mesh includes at least a portion of the second wires interwoven with the thinner first wires; the second wire mesh includes additional wires interwoven with the thicker first wires; The electrochemical cell stack of claim 1 .

24. 1. An electrochemical cell stack comprising: at least two electrochemical cells, each including an anode, a cathode, and an electrolyte located between the anode and the cathode; at least one interconnect located between the at least two electrochemical cells; a contact layer electrically connecting the at least one interconnect and the anode of an adjacent one of the at least two electrochemical cells, the contact layer comprising: a first wire extending in a first direction, the first wire comprising a first material having a first hardness; a second wire extending in a second direction different from the first direction, the second wire including a second material having a second hardness lower than the first hardness; a contact layer comprising: The electrochemical cell stack comprising:

25. the interface layer includes at least one wire mesh; The first wire is thicker than the second wire.

24. The electrochemical cell stack of claim 23.

26. the at least one wire mesh has a plain weave; the first wires include warp wires including a nickel alloy; the second wire comprises a weft wire comprising pure nickel; 25. The electrochemical cell stack of claim 24.

27. 24. The electrochemical cell stack of claim 23, wherein the at least two electrochemical cells comprise solid oxide fuel cells or solid oxide electrolyzer cells.

28. an end plate located adjacent to the anode of the other of the at least two electrochemical cells; another contact layer electrically connecting the anode and the end plate of the other of the at least two electrochemical cells; 24. The electrochemical cell stack of claim 23, further comprising:

29. 1. An electrochemical cell stack comprising: at least two electrochemical cells, each including an anode, a cathode, and an electrolyte located between the anode and the cathode; at least one interconnect located between the at least two electrochemical cells; a contact layer electrically connecting the at least one interconnect and the anode of an adjacent one of the at least two electrochemical cells, the contact layer comprising: a first wire extending in a first direction, the first wire having a first wire density; second wires extending in a second direction different from the first direction, the second wires having a second wire density different from the first density; a contact layer comprising: The electrochemical cell stack comprising:

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