Porous metal sheet, fuel cell, and hydrogen production apparatus

Abstract

This porous metal sheet is formed of a porous metal having a skeleton with a three-dimensional network structure. The porous metal sheet has a main surface in which a plurality of grooves are formed. An upper chamfer is formed on the upper corner of each of the plurality of grooves. A lower chamfer is formed on the lower corner of each of the plurality of grooves.

Description

Metallic porous sheet, fuel cell and hydrogen production device

[0001] The present disclosure relates to a porous metal sheet, a fuel cell, and a hydrogen production device.

[0002] International Publication No. 2020 / 235237 (Patent Document 1) discloses a porous metal sheet having a main surface on which grooves are formed. The porous metal sheet is formed by pressing a mold having a plurality of protrusions against the main surface of the porous metal sheet.

[0003] International Publication No. 2020 / 235237

[0004] The porous metal sheet of the present disclosure is formed from a porous metal having a skeleton with a three-dimensional network structure. The porous metal sheet has a main surface on which a plurality of grooves are formed. An upper chamfer is formed at the upper corner of each of the plurality of grooves. A lower chamfer is formed at the lower corner of each of the plurality of grooves.

[0005] FIG. 1 is a schematic plan view of a metal porous body sheet according to an embodiment. FIG. 2 is a schematic cross-sectional view of a metal porous body sheet according to an embodiment, taken along the section line II-II shown in FIG. 1 . FIG. 3 is a schematic, partially enlarged cross-sectional view of a metal porous body sheet according to an embodiment. FIG. 4 is a schematic view showing the internal structure of a metal porous body sheet according to an embodiment. FIG. 5 is a schematic cross-sectional view showing the internal structure of a metal porous body sheet according to an embodiment. FIG. 6 is a schematic cross-sectional view of a metal porous body sheet according to an embodiment, taken along the section line VI-VI shown in FIG. 5 . FIG. 7 is a flowchart of a method for producing a metal porous body sheet according to an embodiment. FIG. 8 is a schematic, partially enlarged view showing a groove forming step in the method for producing a metal porous body sheet according to an embodiment. FIG. 9 is a schematic, partially cross-sectional view of a fuel cell according to an embodiment. FIG. 10 is a schematic, partially cross-sectional view of a cell of a fuel cell according to an embodiment. FIG. 11 is a schematic, partially cross-sectional view of a hydrogen production apparatus according to an embodiment.

[0006] [Problem to be Solved by the Present Disclosure] In Patent Document 1, when the porous metal sheet is peeled off from the mold for forming the grooves or when tensile stress is applied to the porous metal sheet, the porous metal sheet may tear at the corners of the grooves. The present disclosure has been made in view of the above-mentioned problem, and its purpose is to provide a porous metal sheet that is more resistant to tearing.

[0007] [Effects of the Present Disclosure] According to the present disclosure, it is possible to provide a porous metal sheet that is more resistant to tearing.

[0008] [Outline of the embodiment] First, the embodiments of the present disclosure will be listed and described.

[0009] (1) The porous metal sheet of the present disclosure is formed from a porous metal having a skeleton with a three-dimensional network structure. The porous metal sheet has a main surface on which a plurality of grooves are formed. An upper chamfer is formed at the upper corner of each of the plurality of grooves. A lower chamfer is formed at the lower corner of each of the plurality of grooves.

[0010] Because an upward chamfer is formed at the upper corner, when a groove is formed using a die, the die can be prevented from biting into the metal porous body sheet. The metal porous body sheet is less likely to tear when peeled from the die. Furthermore, tensile stress may be applied to the metal porous body sheet during transportation, when the metal porous body sheet is assembled into a device such as a fuel cell or hydrogen production device, or when the device is in operation. Because a downward chamfer is formed at the lower corner, the metal porous body sheet is less likely to tear even when tensile stress is applied to the metal porous body sheet.

[0011] (2) In the porous metal sheet according to (1) above, the upper chamfer is a first R-chamfer having a first radius of curvature, and the lower chamfer is a second R-chamfer having a second radius of curvature.

[0012] Therefore, the porous metal sheet is less likely to tear when it is peeled off from the mold used to form the grooves, and is also less likely to tear even when tensile stress is applied to the porous metal sheet.

[0013] (3) In the porous metal sheet according to (2) above, the first radius of curvature is 0.05 mm or more.

[0014] This further prevents the mold from biting into the porous metal sheet when forming grooves using the mold, and the porous metal sheet is less likely to tear when peeled off from the mold.

[0015] (4) In the porous metal sheet according to (2) or (3) above, the second radius of curvature is 0.05 mm or more.

[0016] Therefore, even when a tensile stress is applied to the porous metal sheet, the porous metal sheet is even less likely to break.

[0017] (5) In the porous metal sheet according to (2) or (3) above, the second radius of curvature is 0.10 mm or more.

[0018] Therefore, even when a tensile stress is applied to the porous metal sheet, the porous metal sheet is even less likely to break.

[0019] (6) In the porous metal sheet according to any one of (2) to (5) above, the second radius of curvature is equal to or less than half the width of each of the plurality of grooves.

[0020] Therefore, it is possible to form a second R-chamfer having a second radius of curvature at the lower corner of each of the plurality of grooves, making the porous metal sheet even more resistant to tearing even when tensile stress is applied to the porous metal sheet.

[0021] (7) In the porous metal sheet according to any one of (2) to (6) above, the first radius of curvature is equal to or less than half the distance between adjacent grooves among the plurality of grooves.

[0022] This allows the upper corners of each of the grooves to be formed with a first R-chamfer having a first radius of curvature. When forming the grooves using a mold, the mold can be prevented from biting into the porous metal sheet. When peeling the porous metal sheet from the mold, the porous metal sheet is less likely to tear.

[0023] (8) In the porous metal sheet according to any one of (2) to (7) above, the sum of the first radius of curvature and the second radius of curvature is equal to or less than the depth of each of the plurality of grooves.

[0024] Therefore, it is possible to form a first R-chamfer having a first radius of curvature at the upper corner of each of the plurality of grooves, and a second R-chamfer having a second radius of curvature at the lower corner of each of the plurality of grooves. When the porous metal sheet is peeled off from the mold, or even when tensile stress is applied to the porous metal sheet, the porous metal sheet is less likely to tear.

[0025] (9) In the porous metal sheet according to any one of (1) to (8) above, the skeleton of the porous metal sheet contains nickel as a main component.

[0026] Therefore, the porous metal sheet can be suitably used as a current collector for a fuel cell, an electrode for a hydrogen production device, and the like.

[0027] (10) In the porous metal sheet according to (9) above, the skeleton of the porous metal sheet contains at least one of cobalt, tin, and chromium.

[0028] Therefore, the porous metal sheet can be suitably used as a current collector for a fuel cell, an electrode for a hydrogen production device, and the like.

[0029] (11) A fuel cell according to the present disclosure includes the porous metal sheet according to any one of (1) to (10) above, and an interconnector disposed opposite the main surface of the porous metal sheet.

[0030] Therefore, even if tensile stress is applied to the porous metal sheet during assembly and operation of the fuel cell, the porous metal sheet is less likely to break, thereby improving the productivity and lifespan of the fuel cell.

[0031] (12) A hydrogen production device according to the present disclosure includes the metal porous sheet according to any one of (1) to (10) above and an interconnector disposed opposite the main surface.

[0032] Therefore, even if tensile stress is applied to the porous metal sheet during assembly and operation of the water splitting apparatus, the porous metal sheet is less likely to break, thereby improving the productivity and lifespan of the water splitting apparatus.

[0033] [Details of the embodiment] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0034] A porous metal sheet according to an embodiment will be described with reference to Figures 1 to 6. The porous metal sheet 1 is used, for example, as a current collector for a fuel cell or an electrode for a hydrogen production device.

[0035] As shown in FIGS. 1 to 3, the metal porous body sheet 1 has a first main surface 10 and a second main surface 11 opposite the first main surface 10. The first main surface 10 and the second main surface 11 are a pair of surfaces that are relatively larger in area than the other surfaces among the multiple surfaces that make up the metal porous body sheet 1. The first main surface 10 and the second main surface 11 are both end surfaces in the thickness direction of the metal porous body sheet 1. The first main surface 10 and the second main surface 11 each extend in a first direction DR1 and a second direction DR2 perpendicular to the first direction DR1. The thickness direction of the metal porous body sheet 1 is a third direction DR3 perpendicular to the first direction DR1 and the second direction DR2. When viewed in a plan view (hereinafter simply referred to as a "plan view") from the normal direction of the first main surface 10 (i.e., the third direction DR3), the metal porous body sheet 1 has, for example, a rectangular shape. The porous metal sheet 1 has a thickness T. The thickness T is the distance between the first main surface 10 and the second main surface 11.

[0036] A plurality of grooves 12 are formed in the first main surface 10. As shown in FIG. 1 , in a plan view, each of the plurality of grooves 12 extends along a first direction DR1. The longitudinal direction of each of the plurality of grooves 12 is the first direction DR1. The plurality of grooves 12 are arranged in a second direction DR2 at intervals G. For example, the plurality of grooves are arranged periodically in the second direction DR2.

[0037] The total area of ​​the plurality of grooves 12 in plan view is 10 percent or more of the area of ​​the first main surface 10. This makes it possible to reduce pressure loss associated with fluid flow. The total area of ​​the plurality of grooves 12 in plan view may be 30 percent or more of the area of ​​the first main surface 10. The total area of ​​the plurality of grooves 12 in plan view is 90 percent or less of the area of ​​the first main surface 10. This makes it possible to improve the uniformity of fluid flow in the metal porous body sheet 1.

[0038] 2 and 3, in a cross section perpendicular to the first direction DR1, each of the grooves 12 has a generally rectangular shape with chamfered corners. Each of the grooves 12 has side surfaces 12 a, 12 b, a bottom surface 12 c, upper corners 13 a, 13 b, and lower corners 14 a, 14 b.

[0039] The side surface 12a and the side surface 12b face each other in the second direction DR2. The width W of the groove 12 is the distance between the side surface 12a and the side surface 12b. The width W is, for example, 1 mm or more. The width W may be 5 mm or more, or may be 25 mm or more. The gap G between a pair of grooves 12 adjacent to each other in the second direction DR2 is the distance between the side surface 12b of one groove 12 of the pair of grooves 12 and the side surface 12a of the other groove 12 of the pair of grooves 12.

[0040] Each of the multiple grooves 12 has a depth D. The depth D is the distance between the first main surface 10 and the bottom surface 12c of the groove 12. The depth D is 10% or more of the thickness T. Therefore, it is possible to reduce pressure loss associated with the flow of fluid. The depth D may be 30% or more of the thickness T. The depth D is 90% or less of the thickness T. Therefore, it is possible to improve the uniformity of the flow of fluid in the metal porous sheet 1.

[0041] The upper corner 13a is connected to the side surface 12a and the first main surface 10. The upper corner 13b is connected to the side surface 12b and the first main surface 10. An upper chamfer is formed at the upper corners 13a, 13b. The upper chamfer is, for example, a first R-chamfer having a first radius of curvature. The first radius of curvature is equal to or less than half the distance G between adjacent grooves 12. The first radius of curvature is, for example, 0.05 mm or more. The first radius of curvature may be 0.10 mm or more, or may be 0.20 mm or more. The upper chamfer may be a C-chamfer.

[0042] The lower corner 14a is connected to the side surface 12a and the bottom surface 12c. The lower corner 14b is connected to the side surface 12b and the bottom surface 12c. A lower chamfer is formed on the lower corners 14a, 14b. The lower chamfer is, for example, a second R-chamfer having a second radius of curvature. The second radius of curvature is equal to or less than half the width W of each of the plurality of grooves 12. The second radius of curvature is, for example, 0.05 mm or more. The second radius of curvature may be 0.10 mm or more, or may be 0.20 mm or more. The sum of the first radius of curvature and the second radius of curvature is equal to or less than the depth D of each of the plurality of grooves. The lower chamfer may be a C-chamfer.

[0043] As shown in Fig. 4, the porous metal sheet 1 is formed from a porous metal. The porous metal has a skeleton 16 with a three-dimensional network structure. As shown in Figs. 5 and 6, the skeleton 16 has a hollow cylindrical shape. That is, the skeleton 16 has a skeleton main body 16a and an internal space 16b defined by the skeleton main body 16a. Note that the skeleton 16 may be solid and not have the internal space 16b.

[0044] As shown in Fig. 6, the skeleton body 16a has, for example, a triangular shape in a cross section perpendicular to its extension direction. This triangular shape does not have to be a mathematically strict triangular shape. The skeleton body 16a is formed of a metal material. For example, the skeleton body 16a contains nickel as a main component. In this specification, the "main component" of the skeleton body 16a means the component that accounts for the largest mass percentage in the skeleton body 16a. The "main component" of the skeleton body 16a may also be a component that accounts for more than 50 mass% of the skeleton body 16a.

[0045] The skeleton body 16a may be made of, for example, nickel (Ni) or a nickel alloy. The skeleton body 16a may also contain at least one of cobalt, tin, and chromium. For example, the skeleton body 16a may be made of a nickel-cobalt (NiCo) alloy, a nickel-tin (NiSn) alloy, a nickel-chromium (NiCr) alloy, or a nickel-tin-chromium (NiSnCr) alloy.

[0046] A porous metal sheet 1 made of a NiCo alloy is suitable as a current collector for a solid oxide fuel cell (SOFC). This is because, even if the SOFC cell is deformed due to heat, the current collector made of the porous metal sheet 1 made of a NiCo alloy can maintain good contact between the current collector and the SOFC cell. Furthermore, a porous metal body containing nickel as a primary component and at least one of tin and chromium has corrosion resistance and oxidation resistance. Therefore, a porous metal body containing nickel as a primary component and at least one of tin and chromium is suitable as an air electrode current collector for an SOFC.

[0047] As shown in Figures 4 and 5, in the metal porous body, the spaces between the skeletons 16 are pores. The porosity of the metal porous body is, for example, 40% or more and 98% or less. The porosity of the metal porous body is given by the following formula (1): Porosity (%) = (1 - (M / (V x d)) x 100 (1), where M is the mass of the metal porous body [g] and V is the apparent volume of the metal porous body [cm ３ d: density of the metal material constituting the skeleton [g / cm ３In addition to the above examples, the porous metal sheet 1 may be formed from a sintered body of a material having pores formed therein.

[0048] (Method for manufacturing a porous metal sheet) An example of a method for manufacturing a porous metal sheet according to an embodiment will be described with reference to Figures 7 and 8. The example method for manufacturing a porous metal sheet 1 includes a porous metal body forming step S1 and a groove forming step S2. The porous metal body forming step S1 includes a base porous body preparing step S11, a conductive treatment step S12, a plating step S13, and a post-treatment step S14.

[0049] In the base porous body preparation step S11, a base porous body is prepared. The base porous body is a porous body made of a resin material such as urethane foam or styrene foam. The base porous body has a sheet shape.

[0050] In the conductive treatment step S12, a conductive coating layer is formed on the surface of the base porous body. The conductive coating layer is made of a conductive material such as a metal material or a carbon material. The conductive treatment step S12 is performed by sputtering, plating, or the like.

[0051] In the plating step S13, a material constituting the skeleton body 16a is formed on the surface of the base porous body (i.e., the conductive coating layer). The plating step S13 is performed by, for example, electroplating.

[0052] In the post-treatment step S14, the base porous body is removed. The post-treatment step S14 includes a first heat treatment and a second heat treatment. The first heat treatment is a heat treatment for removing the base porous body by oxidation. The first heat treatment is performed in an oxidizing atmosphere. As the base porous body is removed by oxidation, the skeletal body 16a formed on the surface of the base porous body is oxidized. The space where the base porous body existed before the first heat treatment becomes the internal space 16b of the skeleton 16 after the first heat treatment. The second heat treatment is a heat treatment performed in a reducing atmosphere for reducing the skeletal body 16a oxidized in the first heat treatment. As a result, a sheet-like metal porous body having a skeleton 16 with a three-dimensional network structure is formed. The sheet-like metal porous body has a first main surface 10 and a second main surface 11.

[0053] 7 and 8, in the groove forming step S2, a plurality of grooves 12 are formed in the first main surface 10. The plurality of grooves 12 are formed using molds 19 and 20.

[0054] Specifically, the second main surface 11 is supported by a mold 19. The mold 20 includes a base portion 21 and a plurality of protrusions 22 protruding from the base portion 21. Each of the plurality of protrusions 22 has lower corners 23a, 23b and upper corners 24a, 24b. A downward chamfer is formed on the lower corners 23a, 23b. The lower corner 23a has a shape complementary to the upper corner 13a. The lower corner 23b has a shape complementary to the upper corner 13b. An upward chamfer is formed on the upper corners 24a, 24b. The upper corner 24a has a shape complementary to the lower corner 14a. The upper corner 24b has a shape complementary to the lower corner 14b.

[0055] The mold 20 is pressed against the first main surface 10 of the sheet-like porous metal body. The shape of the multiple protrusions 22 is transferred to the first main surface 10. Multiple grooves 12 corresponding to the multiple protrusions 22 of the mold 20 are formed in the first main surface 10. Upper corners 13a, 13b corresponding to the lower corners 23a, 23b of the mold 20 are formed in the sheet-like porous metal body. Lower corners 14a, 14b corresponding to the upper corners 24a, 24b of the mold 20 are formed in the sheet-like porous metal body. In this way, the porous metal sheet 1 is formed.

[0056] (Fuel Cell) A fuel cell 30 according to an embodiment will be described with reference to Figures 9 and 10. The fuel cell 30 according to this embodiment is, for example, a solid oxide fuel cell (SOFC). Referring to Figure 9, the fuel cell 30 includes an interconnector 31, an anode current collector 32, cells 33, a cathode current collector 38, and an interconnector 39. Although not shown, the fuel cell 30 has a cell stack structure formed by stacking unit structures each including the interconnector 31, the anode current collector 32, the cells 33, the cathode current collector 38, and the interconnector 39.

[0057] The interconnector 31 is a flat plate-shaped member. The interconnector 31 is formed of, for example, an iron-chromium alloy. The surface of the interconnector 31 that faces the anode current collector 32 is flat. No grooves are formed on the surface of the interconnector 31 that faces the anode current collector 32.

[0058] An anode current collector 32 is disposed on the interconnector 31. The anode current collector 32 is formed of a porous metal sheet 1. The anode current collector 32 is disposed on the interconnector 31 such that the first main surface 10 faces the interconnector 31.

[0059] A cell 33 is disposed on the anode current collector 32. The cell 33 is disposed between the anode current collector 32 and a cathode current collector 38. Referring to Fig. 10, the cell 33 includes an anode 34, a solid electrolyte 35, and a cathode 37. The cell 33 may further include an intermediate layer 36.

[0060] The fuel electrode 34 is a sheet-like porous body. The porous body constituting the fuel electrode 34 is made of, for example, zirconia (ZrO ２ The anode 34 is formed of a mixture of copper and nickel. The anode 34 is disposed on the anode current collector 32 (more specifically, on the second main surface 11).

[0061] The solid electrolyte 35 is a sheet-like member that allows oxygen ions to pass through. The solid electrolyte 35 is made of, for example, yttria-stabilized zirconia (YSZ). The solid electrolyte 35 is disposed on the fuel electrode 34.

[0062] The air electrode 37 is a flat porous body. The porous body constituting the air electrode 37 is, for example, (La, Sr)MnO ３ or (La,Sr)CoO ３ If the cell 33 does not include the intermediate layer 36, the air electrode 37 is disposed on the solid electrolyte 35. If the cell 33 includes the intermediate layer 36, the air electrode 37 is disposed on the intermediate layer 36.

[0063] The intermediate layer 36 is disposed between the solid electrolyte 35 and the air electrode 37. The intermediate layer 36 prevents a reaction between the solid electrolyte 35 and the air electrode 37. The intermediate layer 36 is formed of, for example, a Gd-doped Ce oxide (GDC).

[0064] A cathode current collector 38 is disposed on the cell 33 (more specifically, the cathode 37). The cathode current collector 38 is formed of a porous metal sheet 1. The cathode current collector 38 is disposed on the cathode 37 so that the second main surface 11 faces the cathode 37.

[0065] The interconnector 39 is a flat plate-shaped member. The interconnector 39 is formed of, for example, an iron-chromium alloy. The interconnector 39 is disposed on the air cathode current collector 38 so as to face the first main surface 10 of the air cathode current collector 38. The surface of the interconnector 39 facing the air cathode current collector 38 is flat. No grooves are formed on the surface of the interconnector 39 facing the air cathode current collector 38. Although not shown, the interconnector 39 is electrically connected to the interconnector 31.

[0066] The operation of the fuel cell 30 will be described. A fuel electrode current collector 32 is supplied with a fuel gas, for example, hydrogen (H ２ The anode current collector 32 may be disposed so that the longitudinal direction of the grooves 12 intersects with the supply direction of hydrogen gas, or so that the longitudinal direction of the grooves 12 is parallel to the supply direction of hydrogen gas.

[0067] The air electrode current collector 38 is charged with oxygen (O ２ The air electrode current collector 38 may be disposed so that the longitudinal direction of the grooves 12 intersects with the supply direction of oxygen gas, or so that the longitudinal direction of the grooves 12 is parallel to the supply direction of hydrogen gas.

[0068] The oxygen ions move from the air electrode 37 to the anode 34 through the solid electrolyte 35. The oxygen ions that reach the anode 34 react with hydrogen gas supplied to the anode 34 through the anode current collector 32. As a result, water (H ２O and electrons are generated. These electrons are supplied to the air electrode 37 through the interconnector 31, the interconnector 39, and the air electrode current collector 38, and ionize the oxygen gas supplied to the air electrode 37 through the air electrode current collector 38. The above reaction is repeated, and the fuel cell 30 generates electricity.

[0069] (Hydrogen Production Apparatus) A hydrogen production apparatus 40 according to an embodiment will be described with reference to Fig. 11. The hydrogen production apparatus 40 is, for example, an alkaline water electrolysis apparatus. The hydrogen production apparatus 40 includes an interconnector 41, a hydrogen generation electrode 42, a diaphragm 43, an oxygen generation electrode 44, and an interconnector 45.

[0070] The interconnector 41 is a flat plate-shaped member. The interconnector 41 is made of, for example, nickel. The surface of the interconnector 41 that faces the hydrogen generation electrode 42 is flat. No grooves are formed on the surface of the interconnector 41 that faces the hydrogen generation electrode 42.

[0071] The hydrogen generation electrode 42 is disposed on the interconnector 41. The hydrogen generation electrode 42 is formed of a porous metal sheet 1. The hydrogen generation electrode 42 is disposed on the interconnector 41 such that the first main surface 10 faces the interconnector 41.

[0072] A diaphragm 43 is disposed on the hydrogen generating electrode 42 (more specifically, on the second main surface 11). The diaphragm 43 is an insulator that allows the alkaline aqueous solution to pass through. The diaphragm 43 is formed of, for example, polyphenylene sulfide (PPS) resin.

[0073] An oxygen generating electrode 44 is disposed on the diaphragm 43. The oxygen generating electrode 44 is formed of the porous metal sheet 1. The oxygen generating electrode 44 is disposed on the diaphragm 43 such that the second main surface 11 faces the diaphragm 43.

[0074] The interconnector 45 is a flat plate-shaped member. The interconnector 45 is made of, for example, nickel. The interconnector 45 is disposed on the oxygen evolving electrode 44 so as to face the first main surface 10 of the oxygen evolving electrode 44. The surface of the interconnector 45 facing the oxygen evolving electrode 44 is flat. No grooves are formed on the surface of the interconnector 45 facing the oxygen evolving electrode 44. Although not shown, the interconnector 45 is electrically connected to the interconnector 41.

[0075] The operation of the hydrogen production device 40 will be described. A voltage is applied between the interconnector 41 and the interconnector 45 so that the potential at the hydrogen generation electrode 42 is lower than the potential at the oxygen generation electrode 44. An alkaline aqueous solution is supplied to the hydrogen generation electrode 42 and the oxygen generation electrode 44. The alkaline aqueous solution is, for example, a potassium hydroxide (KOH) aqueous solution or a sodium hydroxide (NaOH) aqueous solution. The alkaline aqueous solution may be supplied to the hydrogen generation electrode 42 and the oxygen generation electrode 44 along a direction intersecting the longitudinal direction of the groove 12, or along a direction parallel to the longitudinal direction of the groove 12.

[0076] At the oxygen generating electrode 44, hydroxide ions contained in the alkaline aqueous solution are oxidized to generate oxygen gas. At the hydrogen generating electrode 42, water is reduced to generate hydrogen gas. These reactions generate hydrogen gas and oxygen gas at the hydrogen generating electrode 42 and the oxygen generating electrode 44.

[0077] EXAMPLES The present disclosure will be described in detail below with reference to examples, although the present disclosure is not limited to these examples.

[0078] The skeleton 16 of the porous metal sheet of Sample No. 1 to Sample No. 16 was formed of nickel. The porosity of the porous metal sheet of Sample No. 1 to Sample No. 16 was 95 percent. A plurality of grooves 12 were formed on the first main surface 10 of the porous metal sheet of Sample No. 1 to Sample No. 16 using molds 19 and 20.

[0079] The porous metal sheets of Samples No. 1 to 16 each had a length of 40 mm and a width of 10 mm. The thickness T, the spacing G between adjacent grooves 12, the depth D, and the width W of the grooves 12 of Samples No. 1 to 16 were as shown in Tables 1 and 2. The upper corners 13a, 13b and the lower corners 14a, 14b of the groove 12 of Sample No. 1 were not chamfered. The upper corners 13a, 13b of the groove 12 of Sample No. 2 were R-chamfered, with a radius of curvature of 0.05 mm. The lower corners 14a, 14b of the groove 12 of Sample No. 2 were not chamfered. Samples No. 3 to 16 were also chamfered. The upper corners 13a, 13b and lower corners 14a, 14b of the grooves 12 of 16 are rounded, and the radii of curvature of the upper corners 13a, 13b and the lower corners 14a, 14b are as shown in Tables 1 and 2. By changing the shape of the mold 20, it is possible to change the spacing G, the depth D of the groove 12, the width W of the groove 12, and the chamfering of the upper corners 13a, 13b and the lower corners 14a, 14b.

[0080] For the porous metal sheets of Samples No. 1 to No. 16, the porous metal sheets were visually observed for breakage during processing and the breaking strength of the porous metal sheets was measured to evaluate the porous metal sheets. Using an Autograph AGX-V (manufactured by Shimadzu Corporation), the porous metal sheets were pulled in the longitudinal direction of the porous metal sheets at a pulling rate of 100 mm / min, and the breaking strength of the porous metal sheets was measured. The breakage and breaking strength of the porous metal sheets during processing are shown in Tables 1 and 2.

[0081]

[0082]

[0083] The lower corners 23a and 23b of the mold 20 used to produce Sample No. 1 are not chamfered. In the porous metal sheet of Sample No. 1, the upper corners 13a and 13b of the grooves 12 are not chamfered. Therefore, when the mold 20 is pressed against the porous metal sheet, the mold 20 bites into the porous metal sheet. When the porous metal sheet of Sample No. 1 is peeled off from the mold 20, the porous metal sheet of Sample No. 1 is torn at the upper corners 13a and 13b.

[0084] The lower corners 23a, 23b of the mold 20 used to produce Sample No. 2 are chamfered. In the porous metal sheet of Sample No. 2, the upper corners 13a, 13b of the grooves are chamfered. This prevents the mold 20 from digging into the porous metal sheet when pressed against it. When the porous metal sheet of Sample No. 2 is peeled off from the mold 20, the porous metal sheet of Sample No. 2 does not tear. However, the upper corners 24a, 24b of the mold 20 used to produce Sample No. 2 are not chamfered. In the porous metal sheet of Sample No. 2, the lower corners 14a, 14b of the grooves 12 are not chamfered. This prevents the porous metal sheet of Sample No. 2 from breaking when tensile stress is applied to the porous metal sheet of Sample No. 2. The porous metal sheet of sample No. 2 is prone to tearing from the lower corners 14a and 14b. The breaking strength of the porous metal sheet of sample No. 2 is only 3.4 MPa.

[0085] In contrast, the lower corners 23a, 23b of the mold 20 used to produce Samples No. 3 to 16 are chamfered. In the porous metal sheets of Samples No. 3 to 16, the upper corners 13a, 13b of the grooves 12 are chamfered. This prevents the mold 20 from digging into the porous metal sheet when pressed against it. When each of the porous metal sheets of Samples No. 3 to 16 is peeled off from the mold 20, each of the porous metal sheets of Samples No. 3 to 16 does not tear.

[0086] Additionally, the upper corners 24a, 24b of the mold 20 used to produce Samples No. 3 to 16 are chamfered. In the porous metal sheets of Samples No. 3 to 16, the lower corners 14a, 14b of the grooves 12 are chamfered. Therefore, even when tensile stress is applied to each of the porous metal sheets of Samples No. 3 to 16, each of the porous metal sheets of Samples No. 3 to 16 is less likely to break at the lower corners 14a, 14b. The breaking strength of each of the porous metal sheets of Samples No. 3 to 16 is greater than the breaking strength of the porous metal sheet of Sample No. 3.

[0087] When the radius of curvature of the R-chamfered upper corners 13a, 13b is 0.05 mm or more, as in the porous metal sheets of Samples No. 3 to 16, the mold 20 is more effectively prevented from digging into the porous metal sheet when pressed against it. When each of the porous metal sheets of Samples No. 3 to 16 is peeled off from the mold 20, each of the porous metal sheets of Samples No. 3 to 16 is even less likely to tear.

[0088] As in the porous metal sheets of Samples No. 3 to 16, the radius of curvature of the R-chamfer of the lower corners 14a, 14b is, for example, 0.05 mm or more. As in the porous metal sheets of Samples No. 5 to 10 and Samples No. 14 to 16, the radius of curvature of the R-chamfer of the lower corners 14a, 14b may be 0.10 mm or more. As in the porous metal sheets of Samples No. 6 to 10 and Samples No. 14 to 16, the radius of curvature of the R-chamfer of the lower corners 14a, 14b may be 0.20 mm or more. As in the porous metal sheets of Samples No. 7 to 10 and Samples No. 14 to 16, the radius of curvature of the R-chamfer of the lower corners 14a, 14b may be 0.20 mm or more. As in the porous metal sheet 16, the radius of curvature of the R-chamfered lower corners 14 a, 14 b may be 0.25 mm or more, so that even if tensile stress is applied to the porous metal sheet, each of the porous metal sheets is less likely to break at the lower corners 14 a, 14 b.

[0089] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present disclosure is defined by the claims, not by the above-described embodiments, and is intended to include any modifications within the scope of the claims and meanings equivalent to the claims.

[0090] 1 metal porous sheet, 10 first main surface, 11 second main surface, 12 groove, 12a, 12b side surface, 12c bottom surface, 13a, 13b upper corner portion, 14a, 14b lower corner portion, 16 skeleton, 16a skeleton main body, 16b internal space, 19, 20 mold, 21 base portion, 22 convex portion, 23a, 23b lower corner portion, 24a, 24b upper corner portion, 30 fuel cell, 31, 39 interconnector, 32 anode current collector, 33 cell, 34 anode, 35 solid electrolyte, 36 intermediate layer, 37 cathode, 38 cathode current collector, 40 hydrogen production device, 41, 45 interconnector, 42 hydrogen evolution electrode, 43 diaphragm, 44 oxygen evolution electrode.

Claims

1. A porous metal sheet, which is formed from a porous metal having a skeleton with a three-dimensional mesh structure, and has a main surface on which a plurality of grooves are formed, with an upper chamfer formed at the upper corner of each of the plurality of grooves, and a lower chamfer formed at the lower corner of each of the plurality of grooves.

2. The porous metal sheet according to claim 1, wherein the upper chamfer is a first R-chamfer having a first radius of curvature, and the lower chamfer is a second R-chamfer having a second radius of curvature.

3. The porous metal sheet according to claim 2, wherein the first radius of curvature is 0.05 mm or more.

4. A porous metal sheet according to claim 2 or claim 3, wherein the second radius of curvature is 0.05 mm or more.

5. A porous metal sheet according to claim 2 or 3, wherein the second radius of curvature is 0.10 mm or more.

6. A porous metal sheet according to any one of claims 2 to 5, wherein the second radius of curvature is equal to or less than half the width of each of the plurality of grooves.

7. A metal porous sheet according to any one of claims 2 to 6, wherein the first radius of curvature is equal to or less than half the distance between adjacent grooves among the plurality of grooves.

8. A metal porous sheet according to any one of claims 2 to 7, wherein the sum of the first radius of curvature and the second radius of curvature is equal to or less than the depth of each of the plurality of grooves.

9. A porous metal sheet according to any one of claims 1 to 8, wherein the skeleton of the porous metal sheet contains nickel as a main component.

10. The porous metal sheet according to claim 9, wherein the skeleton of the porous metal sheet contains at least one of cobalt, tin, and chromium.

11. A fuel cell comprising the porous metal sheet according to any one of claims 1 to 10 and an interconnector disposed opposite the main surface.

12. A hydrogen production device comprising the porous metal sheet according to any one of claims 1 to 10 and an interconnector arranged opposite the main surface.

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