WO2025047085A1 - Mesh, water electrolysis device, and fuel cell - Google Patents

Abstract

This mesh is composed of a skeleton comprising a plurality of support parts and a plurality of node parts. Each of the plurality of node parts connects two or more support parts among the plurality of support parts. The skeleton consists of a skeleton body and an internal part surrounded by the skeleton body. The skeleton body consists essentially of nickel or a nickel alloy.

Description

Mesh, water electrolysis device and fuel cell

This disclosure relates to a mesh, a water electrolysis device, and a fuel cell. This application claims priority to Japanese Patent Application No. 2023-139548, filed on August 30, 2023. All contents of said Japanese Patent Application are incorporated herein by reference.

Metal meshes have traditionally been used in electronic devices and water electrolysis electrodes (Patent Document 1).

JP 2009-185378 A

The mesh according to one embodiment of the present disclosure is comprised of a skeleton having a plurality of strut portions and a plurality of node portions. Each of the plurality of node portions connects two or more of the plurality of strut portions. The skeleton comprises a skeleton body and an interior surrounded by the skeleton body. The skeleton body consists essentially of nickel or a nickel alloy.

FIG. 1 is a plan view of a mesh according to a first embodiment. 2 is an end view of the support portion of the mesh of the first embodiment as viewed from the direction of the arrows II-II in FIG. FIG. 3 is an end view of a node portion of the mesh of the first embodiment as viewed from the direction of the arrows III-III in FIG. FIG. 4 is a flowchart showing a method for manufacturing the mesh of the first embodiment. FIG. 5 is a plan view of the mesh of the second embodiment. FIG. 6 is an end view of the mesh of the second embodiment as viewed from the direction of the arrows VI-VI in FIG. FIG. 7 is a flowchart showing a method for manufacturing a mesh according to the second embodiment. FIG. 8 is a plan view of a mesh according to a first modified example of the second embodiment. FIG. 9 is a plan view of a mesh according to a second modified example of the second embodiment. FIG. 10 is a plan view of a mesh according to a third modified example of the second embodiment. FIG. 11 is a plan view of a mesh according to a fourth modified example of the second embodiment. FIG. 12 is a plan view of a mesh according to a fifth modified example of the second embodiment. FIG. 13 is a schematic partial cross-sectional view of a water electrolysis apparatus according to the third embodiment. FIG. 14 is a schematic partial cross-sectional view of a fuel cell according to the fourth embodiment. FIG. 15 is a schematic partial cross-sectional view of a cell of a fuel cell according to the fourth embodiment.

[Problem that this disclosure aims to solve]
In recent years, metal meshes have been used as water electrolysis electrodes. Metal meshes are required to have excellent mechanical strength and low electrical resistance. However, in meshes formed by weaving drawn metal wires, the warp threads (metal wires) and weft threads (metal wires) are only in contact with each other at their intersections. Therefore, it has been difficult to achieve excellent mechanical strength and low electrical resistance with such meshes.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a mesh having better mechanical strength and lower electrical resistance.
[Effects of this disclosure]
According to the present disclosure, a mesh can be provided that has better mechanical strength and lower electrical resistance.

[Summary of the embodiment of the present disclosure]
First, the embodiments of the present disclosure will be listed and described.

[1] A mesh according to one embodiment of the present disclosure is comprised of a skeleton having a plurality of struts and a plurality of nodes. Each of the plurality of nodes connects two or more of the plurality of struts. The skeleton comprises a skeleton body and an interior surrounded by the skeleton body. The skeleton body consists essentially of nickel or a nickel alloy.

In the mesh of the present disclosure, two or more struts are integrated at the nodes. This provides the mesh with better mechanical strength and lower electrical resistance.

[2] In the above [1], in the central cross section of each of the multiple node parts along the longitudinal direction of one of the two or more support parts, a first ratio of the internal minor axis to the internal major axis may be 0.01 or more and 0.9 or less. In the central cross section of one of the support parts perpendicular to the longitudinal direction, a second ratio of the internal second length to the internal first length may be 0.1 or more and 1.0 or less. The first length is the internal length in the in-plane direction of the mesh in the central cross section of one of the support parts. The second length is the internal length in the thickness direction of the mesh in the central cross section of one of the support parts.

As a result, the surface irregularities of the mesh are reduced. Components adjacent to the mesh are prevented from being broken through by the mesh. If the component is an insulating component such as a diaphragm in a zero-gap water electrolysis cell, the insulating properties of the insulating component can be ensured.

[3] In the above [1] or [2], the content of the first atom in the skeletal body may be 0 ppm or more and 100 ppm or less by mass, and the first atom may be at least one atom selected from the group consisting of phosphorus atoms and boron atoms.

The melting point of nickel or the nickel alloy is lowered by the reducing agent components that are inevitably mixed in during the reduction of the first atoms. As a result, the mesh has better mechanical strength and lower electrical resistance.

[4] In any one of the above [1] to [3], the inside may be hollow.
Therefore, it is possible to provide a mesh that has superior mechanical strength, lower electrical resistance, and is lighter in weight. In addition, by rolling the mesh, the thickness of the mesh can be easily adjusted. The mesh can be easily attached to a member adjacent to the mesh (e.g., a diaphragm of a water electrolysis cell).

[5] In any of the above [1] to [3], the inside may be made of an alkali-resistant resin or an alkali-resistant carbon fiber.

As a result, the mesh has better alkali resistance. Because the inside of the skeleton is solid, the mesh has better mechanical strength. The mesh can be suitably used as a water electrolysis electrode in a water electrolysis device that uses a strong alkaline solution.

[6] In the above [5], the alkali-resistant resin may be at least one resin selected from the group consisting of polypropylene, polyethylene, polyester, nylon, and polytetrafluoroethylene.

As a result, the mesh has better alkali resistance. Because the inside of the skeleton is solid, the mesh has better mechanical strength. The mesh can be suitably used as a water electrolysis electrode in a water electrolysis device that uses a strong alkaline solution.

[7] In any of [1] to [6] above, the opening ratio of the mesh may be 0.2 percent or more and 80 percent or less.

The mesh has an opening rate of 0.2 percent or more, so that the mesh can pass through liquids and gases. The mesh can be suitably used for water electrolysis electrodes in water electrolysis devices that use strong alkaline solutions. In addition, the mesh has an opening rate of 80 percent or less, so that the mesh has superior mechanical strength.

[8] In any of the above [1] to [7], the average circular equivalent diameter of each of the plurality of support parts in a cross section perpendicular to the longitudinal direction of each of the plurality of support parts may be 0.007 mm or more and 0.5 mm or less.

Therefore, the mesh has better mechanical strength.
[9] In any one of the above [1] to [8], the mesh has a main surface on which grooves are formed. The depth of the grooves may be 10% or more of the thickness of the mesh. In a plan view of the main surface, the area of the grooves may be 10% or more of the area of the main surface.

This improves the uniformity of the flow of fluids such as gas and liquid through the mesh.

[10] In the above [9], in the plan view, the mesh has a first edge, a second edge opposite the first edge, a third edge, and a fourth edge opposite the third edge. The third edge and the fourth edge are connected to the first edge and the second edge, respectively. In the plan view, the skeleton may have a lattice shape. Each of the multiple filaments constituting the lattice may extend from one of the first edge, the second edge, the third edge, and the fourth edge to another of the first edge, the second edge, the third edge, and the fourth edge. The minimum value of the ratio of the length of the portion of each of the multiple filaments where the grooves are not formed may be 10 percent or more.

This improves the uniformity of the flow of fluids such as gas and liquid through the mesh.

[11] A water electrolysis device according to one embodiment of the present disclosure includes a current collector, a diaphragm, and an electrode disposed between the current collector and the diaphragm. At least one of the electrodes or the current collector is formed from any one of the meshes described above in [1] to [10].

As a result, the uniformity of the flow of the aqueous solution in at least one of the electrodes or current collectors can be improved. In addition, the discharge of gas generated within the water electrolysis device is promoted. The performance of the water electrolysis device can be improved.

[12] A fuel cell according to one embodiment of the present disclosure includes a current collector, an electrolyte, and an electrode disposed between the current collector and the electrolyte. The current collector is formed from any one of the meshes described above in [1] to [10].

As a result, the uniformity of the gas flow in the current collector can be improved, thereby improving the performance of the fuel cell.

[Details of the embodiment of the present disclosure]
The embodiments of the present disclosure will be described below with reference to the drawings. In the drawings of the present disclosure, the same reference numerals represent the same or corresponding parts. In addition, the dimensional relationships such as length, width, thickness, depth, etc. are appropriately changed for clarity and simplification of the drawings, and do not necessarily represent the actual dimensional relationships.

(Embodiment 1)
A mesh 1 according to a first embodiment will be described with reference to Figures 1 to 3. Figure 1 is a plan view of the mesh 1. Figure 2 is an end view seen from the direction of the arrows II-II in Figure 1. Figure 3 is an end view seen from the direction of the arrows III-III in Figure 1.

The mesh 1 is composed of a skeleton 5 having a plurality of strut sections 6 and a plurality of node sections 7. Each of the plurality of node sections 7 connects two or more of the plurality of strut sections 6. The skeleton 5 is composed of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2. The skeleton body 2 is essentially composed of nickel or a nickel alloy.

As a result, mesh 1 has excellent mechanical strength and low electrical resistance. This is presumably because mesh 1's skeleton 5 does not have a structure in which metal wires contact each other at their intersections, but rather has a structure in which multiple hollow metal wires are connected by metallic bonds at each of multiple node portions 7.

<Mesh 1>
<Structure of Mesh 1>
The mesh 1 according to this embodiment is composed of a skeleton 5 including a plurality of support parts 6 and a plurality of node parts 7. Each of the plurality of node parts 7 connects two or more support parts 6 out of the plurality of support parts 6. Each of the plurality of node parts 7 may connect three or more support parts 6 out of the plurality of support parts 6. Each of the plurality of node parts 7 may connect seven or less support parts 6 out of the plurality of support parts 6, may connect six or less support parts 6 out of the plurality of support parts 6, may connect five or less support parts 6 out of the plurality of support parts 6, or may connect four or less support parts 6 out of the plurality of support parts 6. Each of the plurality of node parts 7 may connect two or more and seven or less support parts 6 out of the plurality of support parts 6, may connect three or more and six or less support parts 6 out of the plurality of support parts 6, may connect three or more and five or less support parts 6 out of the plurality of support parts 6, or may connect three or more and four or less support parts 6 out of the plurality of support parts 6. Each of the multiple node portions 7 may connect three support portions 6, four support portions 6, five support portions 6, six support portions 6, or seven support portions 6. In the present disclosure, the mesh 1 refers to a mesh-like structure. The mesh-like structure is also referred to as a mesh structure.

The average equivalent circle diameter of each of the multiple support parts 6 in a cross section perpendicular to the longitudinal direction of each of the multiple support parts 6 may be 0.007 mm or more and 0.5 mm or less. This allows the mesh 1 to have better mechanical strength. The lower limit of the average equivalent circle diameter of each of the multiple support parts 6 may be 0.007 mm or more, 0.01 mm or more, or 0.1 mm or more. The upper limit of the average equivalent circle diameter of each of the multiple support parts 6 may be 0.5 mm or less, 0.3 mm or less, or 0.2 mm or less. The average equivalent circle diameter of each of the multiple support parts 6 may be 0.01 mm or more and 0.3 mm or less, or 0.1 mm or more and 0.2 mm or less.

The average equivalent circle diameter of the support portion 6 in a cross section perpendicular to the longitudinal direction of the support portion 6 can be determined by the following method. A cross section of the support portion 6 perpendicular to the longitudinal direction of the support portion 6 is produced using a cross section polisher (CP). The cross section of the support portion 6 is then observed using a scanning electron microscope (SEM). Finally, the average value of the equivalent circle diameters of any 10 support portions 6 in the cross section of the support portion 6 is calculated. In this way, the average equivalent circle diameter of the support portion 6 can be determined.

The opening ratio of the mesh 1 may be 0.2% or more and 80% or less. Since the opening ratio of the mesh 1 is 0.2% or more, the fluid can easily pass through the mesh 1 and the mesh 1 is lighter. Since the opening ratio of the mesh 1 is 80% or less, the mesh 1 has better mechanical strength and lower electrical resistance. The lower limit of the opening ratio of the mesh 1 may be 0.2% or more, 6% or more, 10% or more, 20% or more, 25% or more, or 40% or more. The upper limit of the opening ratio of the mesh 1 may be 80% or less, 70% or less, or 60% or less. The opening ratio of the mesh 1 may be 0.2% or more and 70% or less, 60% or more and 80% or less, 6% or more and 70% or less, 10% or more and 70% or less, 20% or more and 70% or less, or 40% or more and 60% or less.

The opening ratio of mesh 1 can be measured using the opening ratio measuring device disclosed in JP 2005-290623 A.

Referring to FIG. 3, the thickness T of the mesh 1 is the maximum thickness of the node portion 7. The thickness T of the mesh 1 may be 0.05 mm or more and 0.5 mm or less. This allows the mechanical strength of the mesh 1 to be further increased. The lower limit of the thickness T of the mesh 1 may be 0.05 mm or more, 0.1 mm or more, or 0.2 mm or more. The upper limit of the thickness T of the mesh 1 may be 0.5 mm or less, 0.4 mm or less, or 0.3 mm or less. The thickness T of the mesh 1 may be 0.1 mm or more and 0.4 mm or less, or 0.2 mm or more and 0.3 mm or less.

The thickness T of the mesh 1 can be determined by the following method. First, a digital thickness gauge (Teclock Corporation) is used to measure the thickness of the node portions 7 at any 10 locations on the mesh 1. Then, the average value of the thicknesses of the node portions 7 at the 10 locations is calculated. In this way, the thickness T of the mesh 1 is determined.

The shape of the openings 4 in the mesh 1 is not particularly limited, but may be, for example, a rectangle, a hexagon, an ellipse, or a triangle. The rectangle may be, for example, a square, a rectangle, or a diamond.

In the skeleton 5, the basis weight may be 10 g/m ² or more and 1000 g/m ² or less. Therefore, breakage is unlikely to occur (in other words, the skeleton 5 is unlikely to break), and the mesh 1 is easy to bend, so that it is easy to manufacture in continuous plating and heat treatment equipment, and the mesh 1 can be made lighter. The lower limit of the basis weight may be 50 g/m ² or more, 100 g/m ² or more, or 200 g/m ² or more. The upper limit of the basis weight may be 800 g/m ² or less, 500 g/m ² or less, or 400 g/m ² or less. The basis weight can be specified by the Archimedes method.

The skeleton 5 is made up of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2. This improves the mechanical strength of the mesh 1, reduces the electrical resistance of the mesh 1, and makes the mesh 1 lightweight, particularly when used as a water electrolysis electrode. Note that "the skeleton 5 is made up of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2" can also be understood as "the composition of the skeleton body 2 is different from the composition of the interior 3 surrounded by the skeleton body 2 in the skeleton 5." Furthermore, "the skeleton 5 is made up of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2" is a concept that also includes, for example, a case where the skeleton 5 has an end face and the interior 3 is exposed to the outside of the mesh 1 at the end face of the skeleton 5.

The fact that "the skeleton 5 is composed of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2" can be identified by the following method. By observing a cross section perpendicular to the longitudinal direction of the support portion 6 at any one point of the skeleton 5, it is confirmed that "the skeleton 5 is composed of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2" at that cross section. Next, it is confirmed in the same manner for any other four points of the skeleton 5 that "the skeleton 5 is composed of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2". From the above, it is identified that "the skeleton 5 is composed of a skeleton body 2 and an interior 3 surrounded by the skeleton body 2" in the mesh 1.

<Body frame>
The skeleton body 2 is essentially made of nickel or a nickel alloy. Therefore, the mechanical strength of the mesh 1 is improved, and the electrical resistance of the mesh 1 can be suppressed to be low. Here, "the skeleton body 2 is essentially made of nickel or a nickel alloy" means that the skeleton body 2 may contain other components other than nickel, within a range that does not impair the effects of the present disclosure. Examples of other components include the first atom described below, cobalt, chromium, tin, copper, and iron. In this embodiment, nickel means a nickel atom. The nickel alloy may be at least one alloy selected from the group consisting of a NiCo alloy, a NiCr alloy, a NiSn alloy, a NiCu alloy, and a NiFe alloy.

The first atom is inevitably contained in the plating solution used in the plating step (S3) described below. The first atom is incorporated into the skeletal body 2 in the plating step (S3). The first atom is, for example, at least one type of atom selected from the group consisting of phosphorus atoms and boron atoms.

The content of the first atom in the skeletal body 2 may be 0 ppm or more and 100 ppm or less on a mass basis. Since nickel and the first atom form a eutectic, the melting point of the skeletal body 2 is lower than the melting point of nickel. Therefore, in the heat treatment step (S4) described later, the mesh 1 becomes more flexible and plating defects in the skeletal body 2 are repaired. The mesh 1 has better mechanical strength and lower electrical resistance. The lower limit of the content of the first atom in the skeletal body 2 may be 0 ppm or more, 5 ppm or more, or 10 ppm or more on a mass basis. The upper limit of the content of the first atom in the skeletal body 2 may be 100 ppm or less, 50 ppm or less, or 30 ppm or less on a mass basis. The content of the first atom in the skeletal body 2 may be 5 ppm or more and 50 ppm or less, or 10 ppm or more and 30 ppm or less.

The composition of the skeletal body 2 can be measured by dissolving all of the metal components of the skeletal body 2 and then performing ICP optical emission spectroscopy and mass spectrometry.

<Inside>
The interior 3 may be hollow. Therefore, the amount of metal in the skeleton main body 2 is kept relatively low, and the surface area of the skeleton 5 is increased. It is possible to provide a mesh 1 that has superior mechanical strength, lower electrical resistance, and is lighter. In addition, since the interior 3 is hollow, the mechanical strength of the mesh 1 in the direction along the diagonal of the rectangle is improved, particularly when the shape of the opening 4 is rectangular.

The fact that the interior 3 is hollow can be identified by the following method. A cross section of the skeleton 5 is taken using CP. Then, the cross section of the skeleton 5 is observed using SEM. In this way, it can be identified that the interior 3 is hollow.

The interior 3 may be made of an alkali-resistant resin or an alkali-resistant carbon fiber. Therefore, the mesh 1 has better alkali resistance. Since the interior 3 of the skeleton 5 is solid, the mesh 1 has better mechanical strength. The mesh 1 can be suitably used as a water electrolysis electrode in a water electrolysis device that uses a strong alkaline solution.

The alkali-resistant resin may be at least one resin selected from the group consisting of polypropylene, polyethylene, polyester, nylon, and polytetrafluoroethylene. The interior 3 may be formed of a material that is more flexible than the skeleton body 2. The interior 3 may be formed of a material that has a smaller specific gravity than the skeleton body 2. Therefore, a composite material is formed of a metal (i.e., nickel or nickel alloy) and a resin that is more flexible than the metal (nickel or nickel alloy). The skeleton 5 is formed of a composite material. Therefore, a mesh 1 that has better mechanical strength, lower electrical resistance, and is lighter can be provided.

The alkali-resistant carbon fiber may be at least one type of carbon fiber selected from the group consisting of polyacrylonitrile (PAN) sintered carbon fiber and pitch-based carbon fiber. This allows the metal (i.e., nickel or nickel alloy) and the carbon fiber, which is more flexible than the metal (nickel or nickel alloy), to form a composite material. The skeleton 5 is formed of the composite material. Therefore, it is possible to provide a mesh 1 that has superior mechanical strength, lower electrical resistance, and is lighter in weight.

　The fact that the inner part 3 is made of an alkali-resistant resin or an alkali-resistant carbon fiber can be identified by the following method. First, the mass of the mesh 1 (hereinafter also referred to as the "first mass") is measured. Next, the mesh 1 is immersed in a KOH solution of about 6 mol/L at 70°C for one week. Next, the immersed mesh 1 is washed with water and then dried. Next, the mass of the dried mesh 1 (hereinafter also referred to as the "second mass") is measured. Next, "[{(first mass) - (second mass)}/(first mass)] x 100" is calculated. If "[{(first mass) - (second mass)}/(first mass)] x 100" is 5% or less, it is identified that "the inner part 3 is made of an alkali-resistant resin or an alkali-resistant carbon fiber."

The wire diameter of the alkali-resistant carbon fiber may be 0.05 mm or more and 0.5 mm or less. Therefore, it is possible to provide a mesh 1 that has better mechanical strength, lower electrical resistance, and is lighter. The lower limit of the wire diameter of the alkali-resistant carbon fiber may be 0.05 mm or more, or 0.07 mm or more. The upper limit of the wire diameter of the alkali-resistant carbon fiber may be 0.5 mm or less, 0.2 mm or less, or 0.1 mm or less. The wire diameter of the alkali-resistant carbon fiber may be 0.05 mm or more and 0.2 mm or less, or 0.07 mm or more and 0.1 mm or less.

The diameter of alkali-resistant carbon fibers can be determined according to the test method for "Carbon fibers - Single fiber diameter and cross-sectional area" in "JIS R7607:2000."

The density of the alkali-resistant carbon fiber may be 1.7 g/cm ³ or more and 1.9 g/cm ³ or less. Therefore, it is possible to provide a mesh 1 that has better mechanical strength, lower electrical resistance, and is lighter. The lower limit of the density of the alkali-resistant carbon fiber may be 1.79 g/cm ³ or more, 1.80 g/cm ³ or more, or 1.81 g/cm ³ or more. The upper limit of the density of the alkali-resistant carbon fiber may be 1.9 g/cm ³ or less, 1.85 g/cm ³ or less, or 1.83 g/cm ³ or less. The density of the alkali-resistant carbon fiber may be 1.79 g/cm ³ or more and 1.85 g/cm ³ or less, or 1.81 g/cm ³ or more and 1.83 g/cm ³ or less.

The density of alkali-resistant carbon fiber can be determined according to the test method for "carbon fiber density" in "JIS R7603:1999."

<First ratio, second ratio>
3 , in a cross section at the center of a node portion 7 along the longitudinal direction of one of two or more strut portions 6 connected by each of the multiple node portions 7, a first ratio D2/D1 of a minor diameter D2 of the interior portion 3 to a major diameter D1 of the interior portion 3 may be 0.01 or more and 0.9 or less. The major diameter D1 of the interior portion 3 is the length of the interior portion 3 in the in-plane direction of the mesh 1 in the cross section at the center of the node portion 7 along the longitudinal direction of the one strut portion 6. The minor diameter D2 of the interior portion 3 is the length of the interior portion 3 in the thickness direction of the mesh 1 in the cross section at the center of the node portion 7 along the longitudinal direction of the one strut portion 6.

Referring to FIG. 2, in a central cross section of one of two or more strut sections 6 connected by each of the multiple node sections 7, perpendicular to the longitudinal direction of the one strut section 6, a second ratio D4/D3 of the second length D4 of the interior 3 to the first length D3 of the interior 3 may be 0.1 or more and 1.0 or less. The first length D3 of the interior 3 is the length of the interior 3 in the in-plane direction of the mesh 1 in the central cross section of the one strut section 6. The second length D4 of the interior 3 is the length of the interior 3 in the thickness direction of the mesh 1 in the central cross section of the one strut section 6.

As a result, the surface irregularities of the mesh 1 are reduced. Members adjacent to the mesh 1 are prevented from being broken by the mesh 1. If the member is an insulating member such as a diaphragm in a zero-gap type water electrolysis cell, the insulating properties of the insulating member can be ensured. Furthermore, if the interior 3 is hollow, the surface area of the mesh 1 is kept large while the node portion 7 is less likely to be damaged. Therefore, it is possible to provide a mesh 1 that has superior mechanical strength, lower electrical resistance, and is lighter in weight.

The lower limit of the first ratio D2/D1 may be 0.01 or more, 0.05 or more, or 0.1 or more. The upper limit of the first ratio D2/D1 may be 0.9 or less, 0.5 or less, or 0.4 or less. The first ratio D2/D1 may be 0.05 or more and 0.5 or less, or 0.1 or more and 0.4 or less.

The first ratio D2/D1 can be determined by the following method. A central cross section of the node portion 7 along the longitudinal direction of one of two or more support portions 6 connected by each of the multiple node portions 7 is taken using a CP. The central cross section of the node portion 7 is then observed using an SEM. The average value of the first ratio D2/D1 at any ten points on the central cross section of the node portion 7 is calculated. In this way, the first ratio D2/D1 can be determined.

The lower limit of the second ratio D4/D3 may be 0.1 or more, 0.2 or more, or 0.4 or more. The upper limit of the second ratio D4/D3 may be 1.0 or less, 0.8 or less, or 0.5 or less. The second ratio D4/D3 may be 0.2 or more and 0.8 or less, or 0.4 or more and 0.5 or less.

The second ratio D4/D3 can be determined by the following method. A central cross section of one of two or more support sections 6 connected by each of a plurality of node sections 7 is taken using CP, the central cross section of the support section 6 being perpendicular to the longitudinal direction of the support section 6. The central cross section of the support section 6 is then observed using SEM. The average value of the second ratio D4/D3 at any ten points on the central cross section of the support section 6 is calculated. In this way, the second ratio D4/D3 can be determined.

<Applications>
The mesh 1 according to the present embodiment can be used as a water electrolysis electrode. The mesh 1 according to the present embodiment can also be suitably used in, for example, a solid oxide fuel cell, a solid oxide steam electrolysis cell, a water electrolysis cell, or an electromagnetic wave shield. Examples of water electrolysis cells include an alkaline water electrolysis cell and an anion exchange membrane water electrolysis cell.

[Method of manufacturing mesh 1]
A method for manufacturing the mesh 1 according to this embodiment will be described with reference to FIG.

The method for manufacturing mesh 1 according to this embodiment includes, for example, a step of preparing a fabric (step S1), a step of obtaining a mesh intermediate (step S2), and a step of plating the surface of the mesh intermediate (step S3), in this order. Furthermore, the method for manufacturing mesh 1 according to this embodiment may further include a heat treatment step (step S4) after the plating step (step S3). The method for manufacturing mesh 1 according to this embodiment may further include a rolling step (step S5).

<Step S1>
In step S1, a dough is prepared. The dough may be prepared by purchasing a commercially available product, or may be prepared by manufacturing the dough by a conventionally known method.

The weave of the fabric may be one type of weave selected from the group consisting of plain weave, twill weave, satin weave, plain tatami weave, herringbone twill weave, twill tatami weave, honeycomb weave, and 3D fabric weave. The wire diameter of the fabric is not particularly limited, but may be, for example, 0.007 mm or more and 2 mm or less. The mesh size of the fabric is not particularly limited, but may be, for example, 0.004 mm or more and 1 mm or less. The pitch of the fabric is not particularly limited, but may be, for example, 0.007 mm or more and 3 mm or less.

The fabric may be made of the above-mentioned alkali-resistant resin or alkali-resistant carbon fiber. Carbon fiber is conductive. Therefore, if the fabric is made of alkali-resistant carbon fiber, step S2 described below may be omitted.

<Step S2>
In step S2, a conductive coating layer is formed on the surface of the fabric. For example, a conductive paste is applied to the surface of the fabric. Then, the solvent is evaporated from the conductive paste. In this manner, a mesh intermediate is obtained. In the conductive paste, the conductive carbon particles may be 3 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the solvent. Examples of the solvent include water. Examples of the conductive carbon particles include natural graphite and artificial graphite. In this disclosure, "conductive" means "electrically conductive".

<Step S3>
In step S3, plating such as nickel plating is applied to the surface of the mesh intermediate. The plating can be performed by a conventionally known method. In the nickel plating, Ni and Co, Cr, Sn, Cu, Fe, etc. may be plated simultaneously, or Co, Cr, Sn, Cu, Fe, etc. may be plated after nickel plating. The mesh 1 having the skeleton 5 with a bare interior is obtained by steps S1 to S3. Step S4 is performed to obtain the mesh 1 having the skeleton 5 with a hollow interior.

<Step S4>
In step S4, the plated mesh intermediate is heat-treated. This heat treatment removes the base material and makes the inside of the skeleton 5 hollow. The conditions of the heat treatment are not particularly limited, but for example, the heat treatment temperature may be 800° C. or higher and 1200° C. or lower, and the heat treatment time may be 5 minutes or higher and 60 minutes or lower. In this way, the mesh 1 having the skeleton 5 with a hollow interior is obtained.

<Step S5>
Step S5 is a rolling process carried out to adjust the thickness of the mesh 1. The mesh 1 having the hollow skeleton 5 obtained in step S3, or the mesh 1 having the hollow skeleton 5 obtained in step S4 is rolled. As shown in FIG. 3, the internal length of the mesh 1 in the thickness direction is reduced, and the thickness of the mesh 1 is reduced. The internal length of the mesh 1 in the thickness direction is smaller than the internal length in the in-plane direction of the mesh 1. In this way, the thickness of the mesh 1 is adjusted.

(Example)
The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

<Preparation of Meshes for Samples 1 to 21>
Meshes relating to Samples 1 to 21 were produced by the following method.

<Dough preparation process>
Fabrics made of the resins shown in Table 1 and having weave, wire diameter, mesh size, and pitch as shown in Table 1 were prepared by purchasing commercially available products.

<Mesh intermediate formation process>
A conductive paste was prepared by dispersing artificial graphite (conductive carbon particles) in 100 parts by mass of water (solvent) using artificial graphite (conductive carbon particles) and an acrylic adhesive as raw materials containing carbon atoms in the parts by mass shown in Table 1. Next, the conductive paste was applied to the surface of the fabric. Next, the conductive paste was vacuum-dried at 80°C for 0.1 hours to volatilize the water (solvent) from the conductive paste. In this way, a mesh intermediate was obtained.

<Plating process>
The mesh intermediate was subjected to nickel plating using the following plating bath composition and electrolysis conditions to obtain a mesh.

(Composition of plating bath)
Salt (aqueous solution): Nickel sulfamate (the plating bath contains nickel at the concentration shown in Table 2)
Boric acid: as shown in Table 2 pH: as shown in Table 2 (Electrolysis conditions)
Temperature: 60°C
Current density: 10A/ ^dm2
Anode: Nickel pellet anode Time: Adjusted according to the metal type and coating weight.

<Heat treatment process>
Among the meshes according to Samples 1 to 21, the meshes according to Samples 1 to 20 were heat-treated under the temperature and time conditions shown in Table 2 to obtain meshes according to Samples 1 to 20 having a hollow skeleton 5. The heat treatment process includes a roasting process in which the resin is burned in an air atmosphere, and a reduction process in which the metal components on the surface of the skeleton oxidized in the roasting process are reduced in a reducing atmosphere. Note that when "-" is written in the "Temperature [°C]" and "Time [min]" columns of the "Heat Treatment Process" column in Table 2, it means that the heat treatment process was not performed.

As a result of the above, "meshes composed of a skeleton having multiple support parts and node parts connecting the support parts in the number listed in Table 3" were manufactured for samples 1 to 21.

<Preparation of Mesh for Sample 101>
A nickel mesh (area weight: 370 g/ ^m2 , pitch: 0.75 mm, wire diameter: 0.15 mm, mesh size: 0.6 mm, weave: plain weave) manufactured by Taiyo Wire Mesh Co., Ltd. was purchased to prepare the mesh for sample 101. In sample 101, the nickel wires are merely crossed, and are not connected to each other by metallic bonds. Therefore, in sample 101, no nodes are formed, and there are no supports connecting the nodes (see Table 3).

<Preparation of Mesh for Sample 102>
The "mesh composed of a skeleton having a plurality of struts and nodes connecting the struts in the number shown in Table 3" according to sample 102 was prepared by the following method. First, nickel plating was performed on the mesh of sample 101 with the following plating bath composition and electrolysis conditions so that the plating amount was 130 g/ ^m2 .

(Composition of plating bath)
Salt (aqueous solution): Nickel sulfamate (containing 90 g/L of nickel in the plating bath)
Boric acid: 20g/L
pH: 4
(Electrolysis conditions)
Temperature: 60°C
Current density: 10A/ ^dm2
Anode: Nickel pellet anode Time: Adjusted according to the metal type and coating weight.

Next, heat treatment was performed at 1000°C for 30 minutes to obtain "a mesh composed of a skeleton having multiple support parts and nodes connecting the support parts in the number shown in Table 3" for sample 102.

<Preparation of mesh for sample 103>
The mesh of sample 103 was prepared by the following method. First, a conductive paste was prepared by dispersing 10 parts by mass of artificial graphite (conductive carbon particles) as a raw material containing carbon atoms in 100 parts by mass of water (solvent) using an acrylic adhesive and artificial graphite (conductive carbon particles). Next, the conductive paste was applied to the surface of a polypropylene single fiber having a wire diameter of 180 μm. Next, the conductive paste was vacuum dried at 80° C. for 0.1 hours. Water (solvent) was volatilized from the conductive paste to obtain a conductive single fiber. Next, nickel plating was performed on the conductive single fiber with the following plating bath composition and electrolysis conditions so that the average thickness of the plating was 5 μm. The average thickness of the plating was determined by measuring the shortest distance from the surface of the single fiber to the surface of the plating at each of five arbitrary locations of the cross section perpendicular to the longitudinal direction of the conductive single fiber plated with nickel, and calculating the average value of the shortest distances at the five locations.

(Composition of plating bath)
Salt (aqueous solution): Nickel sulfamate (containing 90 g/L of nickel in the plating bath)
Boric acid: 20g/L
pH: 4
(Electrolysis conditions)
Temperature: 60°C
Current density: 10A/ ^dm2
Anode: Nickel pellet anode Time: Adjusted according to the metal type and coating weight.

Then, the nickel-plated monofilaments were woven in a plain weave to obtain a mesh intermediate having the following pitch and mesh size. The mesh intermediate was then heat-treated at 1000°C for 30 minutes to obtain the mesh of sample 103. In sample 103, the nickel-plated monofilaments are merely crossed, and are not connected to each other by metallic bonds. Therefore, in sample 103, no nodes are formed, and there are no supports connecting the nodes (see Table 3).

<Mesh characteristic evaluation>
<Skeletal structure>
The presence or absence of "a skeleton consisting of a skeleton main body and an interior surrounded by the skeleton main body" was identified by the method described above. The results obtained are shown in the "Presence or absence of skeleton main body + interior" column in Table 3.

<Composition of the skeleton>
The nickel content in the skeletal body was determined by the method described above. The results obtained are shown in the "Ni content [mass%]" column of the "skeletal body" column in Table 3. The content of the first atom in the skeletal body was determined by the method described above. The results obtained are shown in the "First atom content [mass%]" column of the "skeletal body" column in Table 3.

<First ratio D2/D1 and second ratio D4/D3>
In a central cross section of a node part along the longitudinal direction of one of two or more strut parts connected by each of the multiple node parts, a first ratio D2/D1 of the internal minor diameter D2 to the internal major diameter D1 was determined by the above-mentioned method. The obtained results are shown in the "D2/D1" column of Table 3. In addition, in a central cross section of a strut part perpendicular to the longitudinal direction of one of two or more strut parts connected by each of the multiple node parts, a second ratio D4/D3 of the internal second length D4 to the internal first length D3 was determined by the above-mentioned method. The obtained results are shown in the "D4/D3" column of Table 3.

<Mesh aperture ratio>
The mesh opening ratio was determined by the method described above. The results are shown in the "Mesh opening ratio [%]" column in Table 3.

<Average circle equivalent diameter of the support part in a cross section perpendicular to the longitudinal direction of the support part>
The average equivalent circular diameter of the support portion in a cross section perpendicular to the longitudinal direction of the support portion was determined by the method described above. The results are shown in the "Average equivalent circular diameter [mm]" column of Table 3.

<Mechanical strength of mesh>
The mechanical strength of the mesh was determined using "Autograph AGX-10NVD" (trademark) manufactured by Shimadzu Corporation. The results obtained are shown in the "Mechanical strength [N/10 mm]" column of Table 4. A relatively high value shown in the "Mechanical strength [N/10 mm]" column of Table 4 means that the mechanical strength of the mesh is excellent.

The meshes of Samples 1 to 21 correspond to examples of this embodiment. The meshes of Samples 101 to 103 correspond to comparative examples. It was found that the meshes of Samples 1 to 21 have exceptionally superior mechanical strength compared to the meshes of Samples 101 to 103.

<Mesh Electrical Resistance>
The electrical resistance of the mesh was determined by the following method. For each sample, a square mesh with a side length of 5 cm was prepared. The part of the square mesh that was 5 mm inside in the vertical and horizontal directions from the first corner of the mesh was clamped by a first clip terminal. The part of the square mesh that was 5 mm inside in the vertical and horizontal directions from the second corner of the square mesh that was diagonally opposite the first corner was clamped by a second clip terminal. A current was passed between the first clip terminal and the second clip terminal, and the electrical resistance of the mesh was measured using a "BT3562 BATTERY HiTESTER" manufactured by Hioki E.E.C. Corporation. The results thus obtained are shown in the "Electrical Resistance [mΩ]" column of Table 4. A relatively low value in the "Electrical Resistance [mΩ]" column of Table 4 means that the electrical resistance of the mesh is relatively low. It was found that the meshes of Samples 1 to 21 had significantly lower electrical resistance than the meshes of Samples 101 and 103.

<Frame Weight>
The basis weight of the skeleton was determined by the method described above. The results obtained are shown in the "Basis Weight [g/ ^m2 ]" column of Table 4. A relatively low basis weight of the skeleton means that the mesh is relatively light. It was found that the meshes of Samples 1 to 21 were significantly lighter than the mesh of Sample 102.

<Insulation evaluation test>
The insulating property of the diaphragm sandwiched between two meshes was evaluated by the following method. First, a laminate was obtained by sandwiching a 20 μm-thick polyethylene (PE) diaphragm between two meshes. The PE diaphragm has insulating properties. Next, a pressure of 10 t/cm ² was applied to the laminate, and a current was passed between the two meshes to measure the electrical resistance of the laminate. The insulating property of the diaphragm sandwiched between two meshes was evaluated based on the following evaluation criteria. When the electrical resistance of the laminate was 10 MΩ or more, evaluation criterion A was given. When the electrical resistance of the laminate was 100 kΩ or more and less than 10 MΩ, evaluation criterion B was given. When the electrical resistance of the laminate was less than 100 kΩ, evaluation criterion C was given. The obtained results are shown in the "insulating property" column of Table 4. In the present disclosure, insulating property means the resistance of the diaphragm to electric leakage. When the two meshes are in a "short circuit" state, electrical leakage is likely to occur in the diaphragm, and the insulating properties of the diaphragm are reduced. An evaluation criterion of A or B means that the diaphragm is not broken by the mesh even when pressure is applied to the laminate, and the insulating properties of the diaphragm sandwiched between the two meshes are ensured.

(Evaluation Criteria)
A: No short circuit B: Slight short circuit C: Short circuit

The insulating properties of the diaphragm sandwiched between two meshes in samples 1 to 21 were found to be superior to the insulating properties of the diaphragm sandwiched between two meshes in samples 101 and 102. This is because the meshes in samples 1 to 21 have reduced surface irregularities, so that even if pressure is applied to the mesh and diaphragm stack, the diaphragm (for example, the diaphragm of a zero-gap water electrolysis cell) is prevented from being broken by the mesh.

From the above, it was found that the meshes of Samples 1 to 21 have excellent mechanical strength and low electrical resistance. It was also found that the meshes of Samples 1 to 21 can ensure the insulation of the insulating member (e.g., a diaphragm) sandwiched between the two meshes.

(Embodiment 2)
The mesh 1 of the second embodiment will be described with reference to Figures 5 and 6. The mesh 1 of the second embodiment is configured similarly to the mesh 1 of the first embodiment, but differs from the mesh 1 of the first embodiment in that the mesh 1 of the second embodiment is provided with a plurality of grooves 17.

Mesh 1 has a main surface 10a and a main surface 10b opposite to main surface 10a. Main surface 10a and main surface 10b are spaced apart from each other in the thickness direction of mesh 1. In plan view, mesh 1 has a first edge 11, a second edge 12 opposite to first edge 11, a third edge 13, and a fourth edge 14 opposite to third edge 13. Third edge 13 and fourth edge 14 are connected to first edge 11 and second edge 12, respectively. In this specification, plan view means a plan view of main surface 10a shown in FIG. 5, unless otherwise specified.

In a plan view, the skeleton 5 has a lattice shape. In this embodiment, the lattice is a square lattice, but it may be a triangular lattice or a hexagonal lattice. The multiple filaments 15 constituting the lattice each extend from one of the first edge 11, the second edge 12, the third edge 13, and the fourth edge 14 to another one of the first edge 11, the second edge 12, the third edge 13, and the fourth edge 14. When the skeleton 5 has a square lattice shape as shown in FIG. 5, the multiple filaments 15 are composed of multiple first filaments 15a and multiple second filaments 15b, and the lattice is formed by multiple first filaments 15a and multiple second filaments 15b. The multiple first filaments 15a each extend from the first edge 11 to the second edge 12. The multiple second filaments 15b each extend from the third edge 13 to the fourth edge 14.

A plurality of grooves 17 are formed on the main surface 10a of the mesh 1. For example, each of the plurality of grooves 17 is a long, thin, straight groove. The plurality of grooves 17 are parallel to each other. In a plan view, the plurality of grooves 17 extend in the same direction. Each of the plurality of grooves 17 extends from the first edge 11 to the second edge 12. The longitudinal direction of each of the plurality of grooves 17 may be parallel to the longitudinal direction of the second filament 15b. Each of the plurality of grooves 17 may extend parallel to the second filament 15b.

Each of the grooves 17 has a depth d and a width W. The depth d is given by the difference between the height of the node portion 7 in the area of the mesh 1 where the grooves 17 are not formed and the height of the node portion 7 in the groove 17. The depth d may be 10% or more of the thickness T of the mesh 1, or 30% or more of the thickness T of the mesh 1. The depth d may be 90% or less of the thickness T of the mesh 1. In this embodiment, the thickness T of the mesh 1 is the thickness of the center of the node portion 7 where the grooves 17 are not formed. In a plan view, the area of the grooves 17 may be 10% or more of the area of the main surface 10a, or 30% or more of the area of the main surface 10a. In a plan view, the area of the grooves 17 may be 90% or less of the area of the main surface 10a. In this specification, the area of the grooves 17 means the total area of the grooves 17 in a plan view.

The method for manufacturing mesh 1 of this embodiment will be described with reference to FIG. 7. The method for manufacturing mesh 1 of this embodiment includes the same steps as the method for manufacturing mesh 1 of embodiment 1 shown in FIG. 4, but differs from the method for manufacturing mesh 1 of embodiment 1 in that the method for manufacturing mesh 1 of this embodiment further includes a groove forming step (step S6).

The groove forming step (step S6) is performed after the rolling step (step S5). In the groove forming step (step S6), multiple grooves 17 are formed in the main surface 10a. Specifically, a die (not shown) is pressed against the main surface 10a of the mesh 1. The shape of the convex parts of the die is transferred to the main surface 10a. In this way, the mesh 1 is obtained with multiple grooves 17 formed in the main surface 10a.

Referring to FIG. 8, mesh 1 of a first modified example of this embodiment will be described. In mesh 1 of this modified example of this embodiment, the grooves 17 are each inclined with respect to the first filaments 15a and the second filaments 15b. In a further modified example of this embodiment, the grooves 17 may be formed in a concentric circle shape in a plan view. The grooves 17 may be formed in a spiral shape in a plan view. As shown in FIG. 9, the grooves 17 may be formed in a radial shape in a plan view. As shown in FIG. 10, the grooves 17 may be spaced apart from the first edge 11, the second edge 12, the third edge 13, and the fourth edge 14 in a plan view, and the grooves 17 may be arranged in a lattice shape.

11 and 12, in a plan view, the multiple grooves 17 may be formed of multiple first grooves 17a and multiple second grooves 17b intersecting the multiple first grooves 17a. As shown in FIG. 11, in a plan view, the multiple first grooves 17a may each be parallel to the multiple first filaments 15a, and the multiple second grooves 17b may each be parallel to the multiple second filaments 15b. As shown in FIG. 12, in a plan view, the multiple first grooves 17a may each be inclined with respect to the multiple first filaments 15a and the multiple second filaments 15b, and the multiple second grooves 17b may each be inclined with respect to the multiple first filaments 15a and the multiple second filaments 15b.

In the above modified examples of this embodiment (see, for example, the modified examples shown in Figures 8, 10, and 12), each of the multiple filaments 15 has a portion where the multiple grooves 17 are not formed (hereinafter, sometimes referred to as a "groove-free portion"). The minimum value of the length ratio of the groove-free portion of each of the multiple filaments 15 is 10% or more. Therefore, the mechanical strength of the mesh 1 is improved. The minimum value of the length ratio of the groove-free portion of each of the multiple filaments 15 may be 30% or more, or may be 50% or more. In this specification, the minimum value of the length ratio of the groove-free portion of each of the multiple filaments 15 means the minimum value of the length ratio of the groove-free portion of each of the multiple filaments 15 calculated by dividing the length of the groove-free portion of each of the multiple filaments 15 by the total length of each of the multiple filaments 15.

(Example)
The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

The mesh of sample 34 is similar to the mesh of sample 1 of embodiment 1 (see Tables 1 to 4), but has the number of openings and thickness T shown in Table 5. The number of openings in the mesh is the number of openings per inch (2.54 cm) of length. Sample 34 does not have multiple grooves 17.

The mesh of sample 31 is similar to the mesh of sample 34, but has a number of grooves 17 formed on the main surface 10a of the mesh as shown in Figure 5. The depth d and width of each of the grooves 17, as well as the spacing between adjacent grooves 17, are as shown in Table 5. In the mesh of sample 31, the grooves 17 extend parallel to the second filaments 15b, so that the minimum proportion of the non-grooved portion of each of the filaments 15 is zero.

The meshes of Samples 32 and 33 are similar to the mesh of Sample 31, but in the meshes of Samples 32 and 33, multiple grooves 17 as shown in FIG. 8 are formed on the main surface 10a of the mesh. The multiple grooves 17 are each inclined relative to the multiple first filaments 15a and the multiple second filaments 15b. The minimum value of the proportion of non-groove-forming portions of each of the multiple filaments 15 in the mesh of Sample 32 and the minimum value of the proportion of non-groove-forming portions of each of the multiple filaments 15 in the mesh of Sample 33 are as shown in Table 5.

A solid oxide fuel cell (SOFC) was fabricated in which the anode current collector was formed from a mesh according to one of samples 31 to 34, and the power generation performance and heat cycle characteristics of the SOFC were measured. The prototype SOFC included an anode interconnector, an air electrode interconnector, a solid electrolyte, an air electrode, an anode, an anode current collector, and an air electrode current collector.

The anode interconnector and the cathode interconnector are made of an iron-chromium alloy. The solid electrolyte is disposed between the anode interconnector and the cathode interconnector. The solid electrolyte is made of yttria-stabilized zirconia (YSZ). The anode is disposed between the anode interconnector and the solid electrolyte. The anode is a porous body formed of a composite of nickel (Ni) and yttria-stabilized zirconia (YSZ). The cathode is disposed between the cathode interconnector and the solid electrolyte. The cathode is a porous body formed of lanthanum strontium cobaltite (LSC). The anode current collector is disposed between the anode interconnector and the anode. The anode current collector is formed of a mesh according to one of samples 31 to 34. The cathode current collector is disposed between the cathode interconnector and the cathode. The cathode current collector is formed of silver paste.

The prototype SOFC is heated to a temperature of 760 degrees Celsius. Then, 0.4 liters/min of hydrogen and 0.6 liters/min of air are flowed into the SOFC. Thus, the power generation performance of the SOFC is measured. The heat cycle characteristics of the SOFC are measured as follows. While a current of 0.4 A/ ^cm2 is flowed through the SOFC, 20 heat cycles are applied to the SOFC. In each heat cycle, the temperature of the SOFC changes between 50 degrees Celsius and 760 degrees Celsius. The temperature increase rate and the temperature decrease rate in each heat cycle are 30 degrees/min. The first output voltage of the SOFC at a temperature of 760 degrees Celsius in the first cycle is measured. The second output voltage of the SOFC at a temperature of 760 degrees Celsius in the 20th cycle is measured. The heat cycle characteristics of the SOFC are obtained by expressing the ratio of the second output voltage to the first output voltage as a percentage.

Table 5 shows the power generation performance and heat cycle characteristics of the prototype SOFC. The power generation performance of an SOFC in which the anode current collector is formed from the mesh of one of samples 31 to 33 is higher than the power generation performance of an SOFC in which the anode current collector is formed from the mesh of sample 34. This is because the provision of multiple grooves 17 in the anode current collector reduces the gas pressure loss in the anode current collector, improving the uniformity of the gas flow in the anode current collector.

The heat cycle characteristics of an SOFC in which the fuel electrode current collector is formed from the mesh of one of Samples 32 and 33 are superior to the heat cycle characteristics of an SOFC in which the fuel electrode current collector is formed from the mesh of Sample 31. This is because the minimum value of the non-grooved portion of the mesh of Samples 32 and 33 is greater than the minimum value of the non-grooved portion of the mesh of Sample 31, and the mesh of Samples 32 and 33 has improved mechanical strength compared to the mesh of Sample 31.

(Embodiment 3)
A water electrolysis apparatus 20 according to a third embodiment will be described with reference to Fig. 13. The water electrolysis apparatus 20 is, for example, a zero-gap alkaline water electrolysis apparatus. The water electrolysis apparatus 20 includes bipolar plates 21 and 22, a spacer 23, a diaphragm 30, an anode 31, a cathode 32, a conductive elastic body 33, current collectors 34 and 35, and conductive ribs 36 and 37.

Bipolar plates 21 and 22 are flat plate-shaped members. Bipolar plates 21 and 22 are made of, for example, an iron-chromium alloy.

The spacer 23 is disposed between the bipolar plates 21 and 22. The spacer 23 defines the gap between the bipolar plates 21 and 22. The spacer 23 is made of an insulating material such as polytetrafluoroethylene (PTFE). The diaphragm 30, the anode 31, the cathode 32, the conductive elastic body 33, and the current collectors 34 and 35 are housed in the internal space defined by the bipolar plates 21 and 22 and the spacer 23.

The diaphragm 30 is disposed between the bipolar plates 21 and 22. The diaphragm 30 is supported by the spacer 23. The diaphragm 30 divides the internal space defined by the bipolar plates 21, 22 and the spacer 23 into an anode chamber 28 and a cathode chamber 29. The diaphragm 30 is an insulator and is permeable to ions such as hydroxide ions. The diaphragm 30 is formed, for example, from polyphenylene sulfide (PPS).

The spacer 23 is provided with inlets 24, 25 and outlets 26, 27. The inlet 24 and outlet 26 are connected to the anode chamber 28. The inlet 25 and outlet 27 are connected to the cathode chamber 29. An alkaline aqueous solution flows into the anode chamber 28 from the inlet 24 and into the cathode chamber 29 from the inlet 25. The alkaline aqueous solution is, for example, a potassium hydroxide (KOH) aqueous solution or a sodium hydroxide (NaOH) aqueous solution. Oxygen and the alkaline aqueous solution generated at the anode 31 flow out from the outlet 26. Hydrogen and the alkaline aqueous solution generated at the cathode 32 flow out from the outlet 27.

The anode 31, the current collector 34, and the conductive rib 36 are disposed in the anode chamber 28. The cathode 32, the conductive elastic body 33, the current collector 35, and the conductive rib 37 are disposed in the cathode chamber 29.

The anode 31 is disposed between the bipolar plate 21 and the diaphragm 30. The anode 31 may be in contact with the diaphragm 30. The cathode 32 is disposed between the bipolar plate 22 and the diaphragm 30. The cathode 32 may be in contact with the diaphragm 30. The conductive elastic body 33 is disposed between the cathode 32 and the bipolar plate 22. The conductive elastic body 33 is in contact with the cathode 32.

The current collector 34 is disposed between the bipolar plate 21 and the anode 31. The current collector 34 is in contact with the anode 31. The current collector 34 is pressed against the anode 31 by a conductive rib 36 protruding from the bipolar plate 21. The current collector 35 is disposed between the bipolar plate 22 and the cathode 32. The current collector 35 is in contact with the cathode 32. The current collector 35 is pressed against the cathode 32 by a conductive rib 37 protruding from the bipolar plate 22.

At least one of the anode 31, the cathode 32, the current collector 34, and the current collector 35 is formed of the mesh 1 of any of the first embodiment, second embodiment, and their modifications.

The operation of the water electrolysis device 20 will now be described.
An alkaline aqueous solution is supplied to the anode chamber 28 and the cathode chamber 29 of the water electrolysis device 20 through the inlets 24, 25. A voltage is applied between the bipolar plates 21 and 22 so that the potential of the cathode 32 is lower than the potential of the anode 31. At the cathode 32, water is reduced to generate hydrogen gas and hydroxide ions. The hydroxide ions move from the cathode 32 to the anode 31 through the diaphragm 30. At the anode 31, the hydroxide ions contained in the alkaline aqueous solution are oxidized to generate oxygen gas. The oxygen generated at the anode 31 and the alkaline aqueous solution flow out from the outlet 26. The hydrogen generated at the cathode 32 and the alkaline aqueous solution flow out from the outlet 27.

The water electrolysis device 20 is not limited to an alkaline water electrolysis device, but may be an anion exchange membrane water electrolysis device, etc.

The effects of the water electrolysis device 20 of this embodiment will be described.
The water electrolysis apparatus 20 of this embodiment includes a current collector (current collector 34 or current collector 35), a diaphragm 30, and an electrode (anode 31 or cathode 32) disposed between the current collector and the diaphragm. At least one of the electrodes or the current collector is formed of the mesh 1 according to any one of the first embodiment, the second embodiment, and the modifications thereof.

As a result, the uniformity of the flow of the aqueous solution in at least one of the electrodes or current collectors can be improved. In addition, the discharge of gas generated within the water electrolysis device 20 is promoted. The performance of the water electrolysis device 20 can be improved.

(Embodiment 4)
A fuel cell 40 according to a fourth embodiment will be described with reference to Fig. 14 and Fig. 15. The fuel cell 40 according to the present embodiment is, for example, a solid oxide fuel cell (SOFC). With reference to Fig. 14, the fuel cell 40 includes interconnectors 41 and 42, an anode current collector 43, a cell 44, an air electrode current collector 49, and a spacer 50. Although not shown, the fuel cell 40 has a cell stack structure formed by stacking unit structures including the interconnectors 41 and 42, the anode current collector 43, the cell 44, the air electrode current collector 49, and the spacer 50.

The interconnectors 41 and 42 are flat plate-shaped members. The interconnector 41 is formed, for example, from an iron-chromium alloy. Although not shown, the interconnector 42 is electrically connected to the interconnector 41. A groove 41a may be formed in the surface of the interconnector 41 facing the fuel electrode current collector 43. A groove 42a may be formed in the surface of the interconnector 42 facing the air electrode current collector 49. The interconnector 41 is provided with an inlet 41b and an outlet (not shown). The interconnector 42 is provided with an inlet 42b and an outlet (not shown).

The spacer 50 is disposed between the interconnector 41 and the interconnector 42. The spacer 50 defines the distance between the interconnector 41 and the interconnector 42. The spacer 50 is formed of an insulating material such as mica. The fuel electrode current collector 43, the cell 44, and the air electrode current collector 49 are housed in the internal space defined by the interconnectors 41, 42 and the spacer 50.

The cell 44 is disposed between the interconnector 41 and the interconnector 42. The fuel electrode current collector 43 is disposed between the interconnector 41 and the cell 44. The air electrode current collector 49 is disposed between the interconnector 42 and the cell 44. The cell 44 is disposed between the fuel electrode current collector 43 and the air electrode current collector 49.

Referring to FIG. 15, the cell 44 includes an anode 45, a solid electrolyte 46, and an cathode 48. The cell 44 may further include an intermediate layer 47.

The fuel electrode 45 is a sheet-like porous body. The porous body constituting the fuel electrode 45 is formed of, for example, a composite of zirconia (ZrO ₂ ) and nickel. The fuel electrode 45 may be formed by applying a conductive material to the fuel electrode current collector 43.

The solid electrolyte 46 is disposed between the fuel electrode 45 and the air electrode 48. The solid electrolyte 46 is in contact with the fuel electrode 45. The solid electrolyte 46 is a sheet-like member that allows oxygen ions to pass through. The solid electrolyte 46 is formed, for example, from yttria-stabilized zirconia (YSZ).

The air electrode 48 is a flat porous body. The porous body constituting the air electrode 48 is formed of, for example, (La, Sr) _MnO3 or (La, Sr) _CoO3 . The air electrode 48 may be formed by applying a conductive material to the air electrode current collector 49. When the cell 44 does not include the intermediate layer 47, the air electrode 48 is in contact with the solid electrolyte 46. When the cell 44 includes the intermediate layer 47, the air electrode 48 is in contact with the intermediate layer 47.

The intermediate layer 47 is disposed between the solid electrolyte 46 and the air electrode 48. The intermediate layer 47 prevents a reaction between the solid electrolyte 46 and the air electrode 48. The intermediate layer 47 is formed of, for example, an oxide of Ce doped with Gd (GDC).

The anode current collector 43 is disposed between the interconnector 41 and the cell 44 (more specifically, the anode 45). The anode current collector 43 is in contact with the interconnector 41 and the cell 44 (more specifically, the anode 45). The cathode current collector 49 is disposed between the interconnector 42 and the cell 44 (more specifically, the cathode 48). The cathode current collector 49 is in contact with the interconnector 42 and the cell 44 (more specifically, the cathode 48).

In the fuel cell 40 of this embodiment, at least one of the fuel electrode current collector 43 or the air electrode current collector 49 is formed from the mesh 1 of any of the first embodiment, second embodiment, and their modifications.

The operation of the fuel cell 40 will now be described.
A fuel gas is supplied to the anode current collector 43 and the anode 45 through the inlet 41b. The fuel gas is, for example, hydrogen (H ₂ ) gas. The fuel gas passes through the grooves 41a and is spread over the entire anode current collector 43 and the entire anode 45.

Oxygen gas is supplied to the air electrode current collector 49 and the air electrode 48 through the inlet 42b. The oxygen gas is spread throughout the air electrode current collector 49 and the air electrode 48 through the grooves 42a. Oxygen ions move from the air electrode 48 to the fuel electrode 45 through the solid electrolyte 46. The oxygen ions that reach the fuel electrode 45 react with hydrogen gas supplied to the fuel electrode 45 through the fuel electrode current collector 43. As a result, water (H ₂ O) and electrons are generated. The electrons are supplied to the air electrode 48 through the interconnector 41, the interconnector 42, and the air electrode current collector 49, and ionize the oxygen gas supplied to the air electrode 48 through the air electrode current collector 49. The above reactions are repeated, and the fuel cell 40 generates electricity.

The effects of the fuel cell 40 of this embodiment will be described.
The fuel cell 40 of this embodiment includes a current collector (anode current collector 43 or cathode current collector 49), an electrolyte (solid electrolyte 46), and an electrode (anode 45 or cathode 48) disposed between the current collector and the electrolyte. The current collector is formed of the mesh 1 of any one of the first embodiment, the second embodiment, and their modifications.

As a result, the pressure loss of the gas in the collector is reduced, and the uniformity of the gas flow in the collector is improved. The performance of the fuel cell 40 can be improved.

Embodiments 1 to 4 disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present disclosure is indicated by the claims rather than the above-described embodiments, and is intended to include the meaning equivalent to the claims and all modifications within the scope.

1 mesh, 2 skeleton body, 3 inside, 4 opening, 5 skeleton, 6 support section, 7 node section, 10a, 10b main surface, 11 first edge, 12 second edge, 13 third edge, 14 fourth edge, 15 filament, 15a first filament, 15b second filament, 17 groove, 17a first groove, 17b second groove, 20 water electrolysis device, 21, 22 bipolar plate, 23 spacer, 24, 25, 41b, 42b inlet Inlet, 26, 27 Outlet, 28 Anode chamber, 29 Cathode chamber, 30 Diaphragm, 31 Anode, 32 Cathode, 33 Conductive elastic body, 34, 35 Current collector, 36, 37 Conductive rib, 40 Fuel cell, 41, 42 Interconnector, 41a, 42a Groove, 43 Anode current collector, 44 Cell, 45 Anode, 46 Solid electrolyte, 47 Intermediate layer, 48 Air electrode, 49 Air electrode current collector, 50 Spacer.

Claims (12)

A mesh having a skeleton including a plurality of struts and a plurality of nodes,
Each of the plurality of node portions connects two or more of the plurality of support portions,
The skeleton includes a skeleton body and an interior portion surrounded by the skeleton body,
The mesh, wherein the skeletal body consists essentially of nickel or a nickel alloy. In a central cross section of each of the plurality of node portions along a longitudinal direction of one of the two or more support portions, a first ratio of the inner minor axis to the inner major axis is 0.01 or more and 0.9 or less;
2. The mesh of claim 1, wherein in a cross section at the center of one of the struts perpendicular to the longitudinal direction, a second ratio of the second length of the interior to the first length of the interior is greater than or equal to 0.1 and less than or equal to 1.0, the first length being the length of the interior in the in-plane direction of the mesh in the cross section at the center of the one of the struts, and the second length being the length of the interior in the thickness direction of the mesh in the cross section at the center of the one of the struts. the content of the first atom in the skeleton body is equal to or greater than 0 ppm and equal to or less than 100 ppm by mass,
3. The mesh of claim 1 or claim 2, wherein the first atom is at least one atom selected from the group consisting of phosphorus atoms and boron atoms. The mesh according to any one of claims 1 to 3, wherein the interior is hollow. The mesh according to any one of claims 1 to 3, wherein the interior is made of an alkali-resistant resin or an alkali-resistant carbon fiber. The mesh according to claim 5, wherein the alkali-resistant resin is at least one resin selected from the group consisting of polypropylene, polyethylene, polyester, nylon, and polytetrafluoroethylene. The mesh according to any one of claims 1 to 6, wherein the opening ratio of the mesh is 0.2 percent or more and 80 percent or less. The mesh according to any one of claims 1 to 7, wherein the average circular equivalent diameter of each of the plurality of support parts in a cross section perpendicular to the longitudinal direction of each of the plurality of support parts is 0.007 mm or more and 0.5 mm or less. The mesh has a main surface having grooves formed thereon,
the depth of the groove is equal to or greater than 10 percent of the thickness of the mesh;
The mesh according to claim 1 , wherein, in a plan view of the main surface, the area of the grooves is 10 percent or more of the area of the main surface. In the plan view, the mesh has a first edge, a second edge opposite the first edge, a third edge, and a fourth edge opposite the third edge, the third edge and the fourth edge being connected to the first edge and the second edge, respectively;
In the plan view, the skeleton has a lattice shape, and each of the plurality of filaments constituting the lattice extends from one of the first edge, the second edge, the third edge, and the fourth edge to another of the first edge, the second edge, the third edge, and the fourth edge,
10. The mesh of claim 9, wherein a minimum value of a percentage of the length of the portion of each of the plurality of filaments where the grooves are not formed is 10 percent or greater. A current collector;
A diaphragm;
an electrode disposed between the current collector and the diaphragm;
A water electrolysis apparatus, wherein at least one of the electrodes or the current collectors is formed of the mesh according to any one of claims 1 to 10. A current collector;
An electrolyte;
an electrode disposed between the current collector and the electrolyte;
A fuel cell, wherein the current collector is formed of the mesh according to any one of claims 1 to 10.

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