WO2023176242A1 - Electrochemical cell - Google Patents

Electrochemical cell Download PDF

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Publication number
WO2023176242A1
WO2023176242A1 PCT/JP2023/004783 JP2023004783W WO2023176242A1 WO 2023176242 A1 WO2023176242 A1 WO 2023176242A1 JP 2023004783 W JP2023004783 W JP 2023004783W WO 2023176242 A1 WO2023176242 A1 WO 2023176242A1
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WO
WIPO (PCT)
Prior art keywords
electrode layer
metal plate
pores
pore
hole
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PCT/JP2023/004783
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French (fr)
Japanese (ja)
Inventor
玄太 寺澤
明浩 杉江
俊之 中村
誠 大森
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日本碍子株式会社
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Publication of WO2023176242A1 publication Critical patent/WO2023176242A1/en

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • C25B11/031—Porous electrodes
    • C25B11/032—Gas diffusion electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/60—Constructional parts of cells
    • C25B9/65—Means for supplying current; Electrode connections; Electric inter-cell connections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/1213—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the electrode/electrolyte combination or the supporting material
    • H01M8/1226—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the electrode/electrolyte combination or the supporting material characterised by the supporting layer

Definitions

  • the present invention relates to an electrochemical cell.
  • an electrochemical cell such as an electrolytic cell or a fuel cell
  • a structure in which a cell body is supported by a metal plate is known.
  • an electrode layer, an electrolyte layer, and a counter electrode layer are laminated in this order on a metal plate.
  • the metal plate has through holes for supplying gas to the electrode layer.
  • the electrode layer is arranged on a metal plate with through holes, the electrode layer is not supported on the through holes, so if the electrode layer is formed thin, cracks may occur in the electrode layer. There is a problem that occurs.
  • an object of the present invention is to suppress cracking of an electrode layer formed on a metal plate.
  • An electrochemical cell includes a cell main body and a metal plate.
  • the cell main body includes a first electrode layer, a second electrode layer, and an electrolyte layer.
  • An electrolyte layer is disposed between the first electrode layer and the second electrode layer.
  • the metal plate supports the cell body.
  • the metal plate has a first main surface, a second main surface, and a through hole.
  • the first electrode layer has a main body portion, a filling portion, at least one first pore, and at least one second pore.
  • the main body portion is arranged on the first main surface of the metal plate.
  • the filling part is arranged within the through hole.
  • the first pore is arranged within the main body.
  • the second pores are arranged within the filling part.
  • the equivalent circle diameter of the largest second pore among the second pores is larger than the equivalent circle diameter of the largest second pore among the first pores.
  • the filling portion of the first electrode layer is arranged within the through hole of the metal plate, cracking of the first electrode layer formed on the metal plate can be suppressed.
  • the filling part contracts during the reduction process, for example.
  • the maximum second pores which are larger than the maximum first pores, are arranged within the filling part. Therefore, the second pores stop the cracks generated within the filled portion from expanding. As a result, cracks can be prevented from extending and penetrating the electrolyte layer.
  • the largest second pores are arranged on the second main surface side within the filling part.
  • the largest second pores are spaced apart from the inner wall surface defining the through hole.
  • the largest second pores contact the inner wall surface defining the through hole.
  • FIG. 7 is an enlarged sectional view showing details of an electrolytic cell according to a modification.
  • FIG. 7 is an enlarged sectional view showing details of an electrolytic cell according to a modification.
  • FIG. 7 is an enlarged sectional view showing details of an electrolytic cell according to a modification.
  • FIG. 1 is a sectional view showing an electrolytic cell.
  • the solid oxide electrolytic cell will be abbreviated as "cell”.
  • the cell 1 includes a cell main body 10 and a metal plate 4. Further, the cell 1 further includes a flow path member 3.
  • the flow path member 3 is joined to the metal plate 4.
  • the channel member 3 has a channel 31 .
  • the flow path 31 is formed on the surface of the flow path member 3 that faces the metal plate 4 .
  • a flow path 31 is formed on the upper surface of the flow path member 3.
  • the flow path 31 is open toward the metal plate 4.
  • the flow path 31 is connected to a manifold (not shown) or the like. In this embodiment, raw material gas is supplied to the flow path 31.
  • the flow path member 3 can be made of an alloy material, for example.
  • the flow path member 3 may be formed of the same material as the metal plate 4.
  • the flow path member 3 has a frame 32 and an interconnector 33.
  • the frame body 32 is an annular member that surrounds the sides of the flow path 31 .
  • the frame body 32 is joined to the metal plate 4.
  • the interconnector 33 is a plate-like member that electrically connects the electrolytic cell 1 to an external power source or other electrolytic cells in series.
  • the interconnector 33 is joined to the frame 32.
  • the frame 32 and the interconnector 33 are separate members, but the frame 32 and the interconnector 33 may be composed of one member.
  • the metal plate 4 supports the cell main body part 10.
  • the metal plate 4 is formed into a plate shape.
  • the metal plate 4 may be flat or curved.
  • the thickness of the metal plate 4 is not particularly limited as long as it can maintain the strength of the cell 1, and may be, for example, 0.1 mm or more and 2.0 mm or less.
  • the metal plate 4 has a first main surface 41, a second main surface 42, and a plurality of through holes 43.
  • the first main surface 41 of the metal plate 4 supports the cell main body part 10.
  • the second main surface 42 of the metal plate 4 faces the flow path 31.
  • the upper surface of the metal plate 4 is the 1st main surface 41
  • the lower surface of the metal plate 4 is the 2nd main surface 42.
  • the frame 32 of the channel member 3 is connected to the second main surface 42 of the metal plate 4 .
  • the metal plate 4 has a rectangular shape in plan view. Note that the metal plate 4 may have other shapes such as a circular shape.
  • the plurality of through holes 43 are arranged along the longitudinal direction and the lateral direction of the metal plate 4.
  • the plurality of through holes 43 are formed in a region of the metal plate 4 that is joined to a hydrogen electrode layer 5, which will be described later.
  • the through hole 43 is open to the first main surface 41 .
  • the through hole 43 is also open to the second main surface 42 . That is, the through hole 43 penetrates the metal plate 4 in the thickness direction.
  • the through hole 43 communicates with the flow path 31 of the flow path member 3.
  • the through hole 43 has a substantially circular shape in plan view.
  • the area of the through hole 43 in plan view can be, for example, 0.00005 mm 2 or more and 1 mm 2 or less. Further, the diameter of the through hole 43 can be, for example, 10 ⁇ m or more and 1000 ⁇ m or less. Note that the through hole 43 may have a rectangular shape in plan view.
  • the source gas flowing through the flow path 31 is supplied to the hydrogen electrode layer 5 via the through hole 43.
  • a portion of the cell main body 10 is inserted into the through hole 43. Specifically, a part of the hydrogen electrode layer 5 of the cell main body 10 enters into the through hole 43.
  • the through hole 43 can be formed by mechanical processing (eg, punching), laser processing, chemical processing (eg, etching), or the like.
  • the metal plate 4 may also be made of porous metal in order to have gas permeability.
  • the metal plate 4 is made of a metal material.
  • the metal plate 4 is made of an alloy material containing Cr (chromium).
  • Cr chromium
  • Fe--Cr alloy steel stainless steel, etc.
  • Ni--Cr alloy steel etc.
  • the content of Cr in the metal plate 4 is not particularly limited, but may be 4% by mass or more and 30% by mass or less.
  • the metal plate 4 may contain Ti (titanium) or Zr (zirconium). Although the content rate of Ti in the metal plate 4 is not particularly limited, it can be set to 0.01 mol% or more and 1.0 mol% or less. Although the Zr content in the metal plate 4 is not particularly limited, it can be set to 0.01 mol% or more and 0.4 mol% or less.
  • the metal plate 4 may contain Ti as TiO 2 (titania), or may contain Zr as Zr (zirconium).
  • the metal plate 4 may have a chromium oxide film on its surface.
  • the chromium oxide film covers at least a portion of the surface of the metal plate 4.
  • the chromium oxide film only needs to cover at least a portion of the surface of the metal plate 4, but may cover substantially the entire surface. Further, the chromium oxide film may cover the inner wall surface of the through hole 43.
  • the chromium oxide film contains chromium oxide as a main component.
  • composition X "contains substance Y as a main component” means that substance Y accounts for 70% by weight or more of the entire composition X.
  • the thickness of the chromium oxide film is not particularly limited, but may be, for example, 0.1 ⁇ m or more and 20 ⁇ m or less.
  • the cell main body 10 is arranged on the first main surface 41 of the metal plate 4.
  • the cell main body 10 includes a hydrogen electrode layer 5 (cathode), an electrolyte layer 7, a reaction prevention layer 8, and an oxygen electrode layer 9 (anode).
  • the hydrogen electrode layer 5, the electrolyte layer 7, the reaction prevention layer 8, and the oxygen electrode layer 9 are laminated in this order from the metal plate 4 side. Note that the cell main body 10 does not need to have the reaction prevention layer 8.
  • the hydrogen electrode layer 5 is an example of the first electrode layer of the invention
  • the oxygen electrode layer 9 is an example of the second electrode layer of the invention.
  • Hydrogen electrode layer 5 is supported by metal plate 4 . Specifically, the hydrogen electrode layer 5 is arranged on the first main surface 41 of the metal plate 4. As shown in FIG. 2, the hydrogen electrode layer 5 is provided so as to cover a region of the metal plate 4 in which the plurality of through holes 43 are provided.
  • the hydrogen electrode layer 5 has a main body portion 51 and a plurality of filling portions 52.
  • the main body portion 51 is arranged on the first main surface 41 of the metal plate 4.
  • the thickness t of the main body portion 51 can be, for example, 1 ⁇ m or more and 100 ⁇ m or less.
  • the main body portion 51 is thinner than the metal plate 4.
  • the filling part 52 is arranged within the through hole 43.
  • the filling portion 52 may fill the entire through hole 43 as shown in FIG. 3, or may fill only a part of the through hole 43 as shown in FIG. Further, as shown in FIG. 5, the filling portion 52 may protrude from the through hole 43 toward the second main surface 42 side. In this case, the filling portion 52 may be joined to the second main surface 42.
  • the filling part 52 is formed integrally with the main body part 51.
  • the diameter of the filling part 52 is substantially the same as the diameter of the through hole 43.
  • the height h of the filling part 52 is greater than the thickness t of the main body part 51.
  • the height h of the filling portion 52 can be, for example, 100 ⁇ m or more and 1000 ⁇ m or less. Note that the height h of the filling portion 52 means the dimension in the vertical direction in FIG.
  • the hydrogen electrode layer 5 has a plurality of first pores 53 and a plurality of second pores 54.
  • the first pores 53 are arranged within the main body portion 51 . That is, the first pores 53 are arranged on the electrolyte layer 7 side with respect to the first main surface 41 of the metal plate 4.
  • the second pores 54 are arranged within the filling part 52. That is, the second pores 54 are arranged within the through holes 43 of the metal plate 4.
  • a plurality of second pores 54 are arranged within one filling part 52.
  • the largest second pore 54 is referred to as the largest second pore 54. Note that when only one second pore 54 is formed in one filling part 52, that one second pore 54 is the maximum second pore 54.
  • the largest second pores 54 are spaced apart from the inner wall surface defining the through hole 43. Moreover, it is preferable that the largest second pores 54 are arranged on the second main surface 42 side within the filling part 52 . Note that the largest second pores 54 may be arranged on the first main surface 41 side within the filling part 52. Further, the largest second pores 54 may be in contact with the inner wall surface defining the through hole 43.
  • a plurality of first pores 53 are arranged within the main body portion 51.
  • the largest first pore 53 is referred to as the largest first pore 53.
  • the equivalent circle diameter of the maximum second pores 54 is larger than the equivalent circle diameter of the maximum first pores 53.
  • the maximum equivalent circle diameter of the second pores 54 can be twice or more the equivalent circle diameter of the maximum first pores 53.
  • the maximum equivalent circle diameter of the second pores 54 can be 80 times or less the equivalent circle diameter of the maximum first pores 53.
  • the average value of the equivalent circle diameters of the plurality of second pores 54 arranged in one filling part 52 is larger than the average value of the equivalent circle diameters of the first pores 53.
  • the equivalent circular diameter of the maximum second pores 54 is measured as follows. First, as shown in FIG. 1, a cut surface is formed so that the through hole 43 can be confirmed. At this cut surface, the inside of the through hole 43 is photographed with a SEM (scanning electron microscope) at a magnification of 200, and the SEM photograph is subjected to image processing to measure the area of each second pore 54 in the filling portion 52.
  • the second pore 54 with the largest area is defined as the largest second pore 54, and the diameter of a circle having the same area as the largest second pore 54 is defined as the equivalent circular diameter of the largest second pore 54.
  • the equivalent circular diameter of the maximum first pore 53 is measured as follows. First, the cell main body 10 is filled with resin and cut near the center. The main body portion 51 is brought into a mirror state by mechanical polishing, and 20 SEM photographs are taken at a magnification of 1000. Then, each SEM photograph is subjected to image processing, and the largest pore among them is determined as the largest first pore 53. Then, the diameter of a circle having the same area as the maximum first pore 53 is defined as the circle equivalent diameter of the maximum first pore 53.
  • the equivalent circle diameter of the maximum second pore 54 formed in any one of the plurality of filling parts 52 is larger than the equivalent circle diameter of the maximum first pore 53. That is, all of the equivalent circle diameters of the maximum second pores 54 formed in each filling portion 52 do not need to be larger than the equivalent circle diameters of the maximum first pores 53.
  • the equivalent circle diameter of the maximum second pores 54 is larger than the equivalent circle diameter of the maximum first pores 53 in 10% or more of the plurality of filling portions 52 .
  • the above ratio is confirmed, for example, as follows. First, the maximum equivalent circle diameter of the second pores 54 in each of the 100 arbitrary filling portions 52 is measured. Then, among the 100 filled portions 52, the ratio of the filled portions 52 having the maximum second pores 54 having an equivalent circle diameter larger than the equivalent circle diameter of the maximum first pores 53 is checked. It is preferable that this ratio is 10% or more.
  • the maximum equivalent circle diameter of the second pores 54 is preferably 10% or more and 70% or less of the diameter of the through hole 43.
  • the hydrogen electrode layer 5 is porous. Although the porosity of the hydrogen electrode layer 5 is not particularly limited, it can be, for example, 20% or more and 70% or less.
  • Raw material gas is supplied to the hydrogen electrode layer 5 through the through hole 43 .
  • the source gas contains CO 2 and H 2 O.
  • the hydrogen electrode layer 5 generates H 2 , CO, and O 2 ⁇ from the raw material gas according to the electrochemical reaction of co-electrolysis shown in equation (1) below.
  • ⁇ Hydrogen electrode layer 5 CO 2 +H 2 O+4e - ⁇ CO+H 2 +2O 2 -...(1)
  • the hydrogen electrode layer 5 is made of a porous material having electron conductivity.
  • the hydrogen electrode layer 5 may have oxide ion conductivity.
  • the hydrogen electrode layer 5 is made of, for example, 8 mol% yttria-stabilized zirconia (8YSZ), calcia-stabilized zirconia (CSZ), scandia-stabilized zirconia (ScSZ), gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), (La ,Sr)(Cr, Mn)O3, (La,Sr)TiO3, Sr2(Fe,Mo)2O6 , ( La , Sr) VO3 , (La,Sr) FeO3 , and among these It can be composed of a mixed material combining two or more of them, or a composite of one or more of these and NiO.
  • This hydrogen electrode layer 5 can be formed as follows. First, a paste for the main body portion 51 and a paste for the filling portion 52 are prepared.
  • the paste for the main body portion 51 includes any of the above-mentioned materials and a pore-forming material containing an organic component.
  • the paste for the filling part 52 is prepared in the same way as the paste for the main body part 51. Note that the pore-forming material contained in the paste for the filling portion 52 is larger than the pore-forming material contained in the paste for the main body portion 51 .
  • paste for the filling portion 52 is screen printed into the through hole 43 of the metal plate 4, and squeegeeing is performed to push the paste into the through hole 43 and remove the paste from above the first main surface 41. do.
  • a paste for the main body portion 51 is formed on the first main surface 41 of the metal plate 4 by a screen printing method.
  • the pore-forming material is removed by heating in an electric furnace to form pores, and then fired.
  • the hydrogen electrode layer 5 is formed on the metal plate 4.
  • the electrolyte layer 7 is arranged between the hydrogen electrode layer 5 and the oxygen electrode layer 9. In this embodiment, since the cell main body 10 has the reaction prevention layer 8 , the electrolyte layer 7 is interposed between the hydrogen electrode layer 5 and the reaction prevention layer 8 .
  • the thickness of the electrolyte layer 7 is not particularly limited, but may be, for example, 3 ⁇ m or more and 50 ⁇ m or less.
  • the electrolyte layer 7 is arranged to cover the entire hydrogen electrode layer 5.
  • the outer peripheral portion of the electrolyte layer 7 is joined to the first main surface 41 of the metal plate 4 . This ensures airtightness between the hydrogen electrode layer 5 side and the oxygen electrode layer 9 side, so there is no need to separately seal between the metal plate 4 and the electrolyte layer 7.
  • the electrolyte layer 7 transmits O 2 ⁇ generated in the hydrogen electrode layer 5 to the oxygen electrode layer 9.
  • Electrolyte layer 7 has oxide ion conductivity.
  • the electrolyte layer 7 is made of a dense material.
  • the porosity of the electrolyte layer 7 is about 0% or more and 7% or less.
  • the electrolyte layer 7 is a fired body made of a dense material that has ionic conductivity and no electronic conductivity.
  • the electrolyte layer 7 can be made of, for example, 8YSZ, GDC, ScSZ, SDC, LSGM (lanthanum gallate), or the like.
  • the method for forming the electrolyte layer 7 is not particularly limited, and can be formed by a baking method, a spray coating method, a PVD method, a CVD method, or the like.
  • Reaction prevention layer 8 is arranged on electrolyte layer 7 . Reaction prevention layer 8 is interposed between electrolyte layer 7 and oxygen electrode layer 9.
  • the thickness of the reaction prevention layer 8 is not particularly limited, but may be, for example, 3 ⁇ m or more and 50 ⁇ m or less.
  • the reaction prevention layer 8 prevents the constituent materials of the oxygen electrode layer 9 and the constituent materials of the electrolyte layer 7 from reacting to form a reaction layer with high electrical resistance.
  • the reaction prevention layer 8 is made of a material having oxide ion conductivity.
  • the reaction prevention layer 8 can be made of a ceria-based material such as GDC or SDC.
  • the porosity of the reaction prevention layer 8 is not particularly limited, but may be, for example, 0% or more and 50% or less.
  • the method for forming the reaction prevention layer 8 is not particularly limited, and can be formed by a baking method, a spray coating method, a PVD method, a CVD method, or the like.
  • the oxygen electrode layer 9 is arranged on the opposite side of the hydrogen electrode layer 5 with respect to the electrolyte layer 7. In this embodiment, since the cell 1 has the reaction prevention layer 8 , the oxygen electrode layer 9 is arranged on the reaction prevention layer 8 .
  • the oxygen electrode layer 9 is preferably porous.
  • the porosity of the oxygen electrode layer 9 is not particularly limited, but may be, for example, 20% or more and 70% or less.
  • the thickness of the oxygen electrode layer 9 is not particularly limited, but may be, for example, 10 ⁇ m or more and 100 ⁇ m or less.
  • the oxygen electrode layer 9 is made of a porous material having oxide ion conductivity and electron conductivity.
  • the oxygen electrode layer 9 is made of, for example, (La,Sr)(Co,Fe) O3 , (La,Sr) FeO3 , La(Ni,Fe) O3 , (La,Sr) CoO3 , and (Sm,Sr). ) CoO 3 and an oxide ion conductive material (GDC, etc.).
  • the method for forming the oxygen electrode layer 9 is not particularly limited, and can be formed by a baking method, a spray coating method, a PVD method, a CVD method, or the like.
  • the oxygen electrode layer 9 generates O 2 from O 2 ⁇ transmitted from the hydrogen electrode layer 5 via the electrolyte layer 7 according to the chemical reaction of equation (2) below.
  • ⁇ Oxygen electrode layer 9 2O 2- ⁇ O 2 +4e - (2)
  • the hydrogen electrode layer 5 was described as an example of the first electrode layer, and the oxygen electrode layer 9 was described as an example of the second electrode layer, but the reverse may be used. That is, as shown in FIG. 6, the first electrode layer may be the oxygen electrode layer 9, and the second electrode layer may be the hydrogen electrode layer 5. In this case, the oxygen electrode layer 9 is placed on the metal plate 4. Further, the oxygen electrode layer 9 has a main body portion 91 , a filling portion 92 , first pores 93 , and second pores 94 . Further, a reaction prevention layer 8 is disposed between the oxygen electrode layer 9 and the electrolyte layer 7.
  • the electrolytic cell 1 was described as an example of an electrochemical cell, but the electrochemical cell may be other than an electrolytic cell.
  • the electrochemical cell may be a fuel cell such as a solid oxide fuel cell.
  • the first electrode layer can be used as a fuel electrode (anode), and the second electrode layer can be used as an air electrode (cathode).

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Abstract

An electrochemical cell (1) is provided with a cell body section (10) and a metal plate (4). The cell body section (10) has a first electrode layer (5), a second electrode layer (9), and an electrolyte layer (7). The electrolyte layer (7) is disposed between the first electrode layer (5) and the second electrode layer (9). The metal plate (4) supports the cell body section (10). The metal plate (4) has a first principal surface (41), a second principal surface (42), and a through-hole (43). The first electrode layer (5) has a body section (51), a filling section (52), at least one first air hole (53), and at least one second air hole (54). The body section (51) is disposed on a first principal surface (51) of the metal plate (4). The filling section (52) is disposed in the through-hole (43). The first air hole (53) is disposed in the body section (51). The second air hole (54) is disposed in the filling section (52). The circle-equivalent diameter of the largest second air hole (54) of the second air hole (54) is larger than the circle-equivalent diameter of the largest first air hole (53) of the first air hole (53).

Description

電気化学セルelectrochemical cell
　本発明は、電気化学セルに関する。 The present invention relates to an electrochemical cell.
　電解セル又は燃料電池などの電気化学セルにおいて、金属板によってセル本体部を支持する構造が知られている。例えば、特許文献１に開示された電気化学セルは、金属板上に、電極層、電解質層、及び対極電極層がこの順で積層されている。金属板は、電極層へ気体を供給するために、貫通孔を有している。 In an electrochemical cell such as an electrolytic cell or a fuel cell, a structure in which a cell body is supported by a metal plate is known. For example, in the electrochemical cell disclosed in Patent Document 1, an electrode layer, an electrolyte layer, and a counter electrode layer are laminated in this order on a metal plate. The metal plate has through holes for supplying gas to the electrode layer.
国際公開第２０１８／１８１９２６号International Publication No. 2018/181926
　上述したように、貫通孔が形成された金属板上に電極層を配置した構成にすると、貫通孔上では電極層は支持されていないため、電極層を薄く形成した場合に電極層に割れが発生するという問題がある。 As mentioned above, if the electrode layer is arranged on a metal plate with through holes, the electrode layer is not supported on the through holes, so if the electrode layer is formed thin, cracks may occur in the electrode layer. There is a problem that occurs.
　そこで、本発明の課題は、金属板上に形成された電極層の割れを抑制することにある。 Therefore, an object of the present invention is to suppress cracking of an electrode layer formed on a metal plate.
　本発明のある側面に係る電気化学セルは、セル本体部と、金属板とを備える。セル本体部は、第１電極層、第２電極層、及び電解質層を有する。電解質層は、第１電極層と第２電極層との間に配置される。金属板は、セル本体部を支持する。金属板は、第１主面、第２主面、及び貫通孔を有する。第１電極層は、本体部と、充填部と、少なくとも一つの第１気孔と、少なくとも一つの第２気孔とを有する。本体部は、金属板の第１主面上に配置される。充填部は、貫通孔内に配置される。第１気孔は、本体部内に配置される。第２気孔は、充填部内に配置される。第２気孔のうち最も大きい最大第２気孔の円相当径は、第１気孔のうち最も大きい最大第１気孔の円相当径よりも大きい。 An electrochemical cell according to one aspect of the present invention includes a cell main body and a metal plate. The cell main body includes a first electrode layer, a second electrode layer, and an electrolyte layer. An electrolyte layer is disposed between the first electrode layer and the second electrode layer. The metal plate supports the cell body. The metal plate has a first main surface, a second main surface, and a through hole. The first electrode layer has a main body portion, a filling portion, at least one first pore, and at least one second pore. The main body portion is arranged on the first main surface of the metal plate. The filling part is arranged within the through hole. The first pore is arranged within the main body. The second pores are arranged within the filling part. The equivalent circle diameter of the largest second pore among the second pores is larger than the equivalent circle diameter of the largest second pore among the first pores.
　この構成によれば、第１電極層の充填部が金属板の貫通孔内に配置されているため、金属板上に形成された第１電極層の割れを抑制することができる。なお、このように充填部を配置すると、例えば還元過程において充填部が収縮する。この結果、充填部内にクラックが生じ、そのクラックが電解質層まで伸展し、電解質層を貫通してしまうおそれがある。これに対して、上記のように構成された電気化学セルでは、最大第１気孔よりも大きい最大第２気孔が充填部内に配置されている。このため、充填部内で生じたクラックの伸展が第２気孔によって止められる。この結果、クラックが伸展して電解質層を貫通することを抑制することができる。 According to this configuration, since the filling portion of the first electrode layer is arranged within the through hole of the metal plate, cracking of the first electrode layer formed on the metal plate can be suppressed. Note that when the filling part is arranged in this way, the filling part contracts during the reduction process, for example. As a result, there is a possibility that cracks will occur in the filling portion, and the cracks will extend to the electrolyte layer and penetrate the electrolyte layer. On the other hand, in the electrochemical cell configured as described above, the maximum second pores, which are larger than the maximum first pores, are arranged within the filling part. Therefore, the second pores stop the cracks generated within the filled portion from expanding. As a result, cracks can be prevented from extending and penetrating the electrolyte layer.
　好ましくは、最大第２気孔は、充填部内において、第２主面側に配置される。 Preferably, the largest second pores are arranged on the second main surface side within the filling part.
　好ましくは、最大第２気孔は、貫通孔を画定する内壁面と間隔をあけて配置される。 Preferably, the largest second pores are spaced apart from the inner wall surface defining the through hole.
　好ましくは、最大第２気孔は、貫通孔を画定する内壁面に接触する。 Preferably, the largest second pores contact the inner wall surface defining the through hole.
　本発明によれば、金属板上に形成された電極層の割れを抑制することができる。 According to the present invention, cracking of an electrode layer formed on a metal plate can be suppressed.
電解セルを示す断面図。A cross-sectional view showing an electrolytic cell. 金属板の平面図。A plan view of a metal plate. 電解セルの詳細を示す拡大断面図。An enlarged sectional view showing details of an electrolytic cell. 変形例に係る電解セルの詳細を示す拡大断面図。FIG. 7 is an enlarged sectional view showing details of an electrolytic cell according to a modification. 変形例に係る電解セルの詳細を示す拡大断面図。FIG. 7 is an enlarged sectional view showing details of an electrolytic cell according to a modification. 変形例に係る電解セルの詳細を示す拡大断面図。FIG. 7 is an enlarged sectional view showing details of an electrolytic cell according to a modification.
　以下、本実施形態に係る電解セル（電気化学セルの一例）について図面を参照しつつ説明する。なお、本実施形態では、電解セルの一例として固体酸化物形電解セル（ＳＯＥＣ）を用いて説明する。図１は電解セルを示す断面図である。以下の説明では、固体酸化物形電解セルを「セル」と略称する。 Hereinafter, an electrolytic cell (an example of an electrochemical cell) according to the present embodiment will be described with reference to the drawings. Note that this embodiment will be described using a solid oxide electrolytic cell (SOEC) as an example of an electrolytic cell. FIG. 1 is a sectional view showing an electrolytic cell. In the following description, the solid oxide electrolytic cell will be abbreviated as "cell".
　図１に示すように、セル１は、セル本体部１０と、金属板４とを備える。また、セル１は、流路部材３をさらに備えている。 As shown in FIG. 1, the cell 1 includes a cell main body 10 and a metal plate 4. Further, the cell 1 further includes a flow path member 3.
　　［流路部材３］
　流路部材３は、金属板４に接合される。流路部材３は、流路３１を有する。流路３１は、流路部材３の金属板４と対向する面に形成されている。本実施形態では、流路部材３の上面に流路３１が形成されている。流路３１は、金属板４に向かって開口している。流路３１は、図示しないマニホールドなどに繋がる。本実施形態では、流路３１に原料ガスが供給される。 [Flow path member 3]
The flow path member 3 is joined to the metal plate 4. The channel member 3 has a channel 31 . The flow path 31 is formed on the surface of the flow path member 3 that faces the metal plate 4 . In this embodiment, a flow path 31 is formed on the upper surface of the flow path member 3. The flow path 31 is open toward the metal plate 4. The flow path 31 is connected to a manifold (not shown) or the like. In this embodiment, raw material gas is supplied to the flow path 31.
　流路部材３は、例えば、合金材料によって構成することができる。流路部材３は、金属板４と同様の材料によって形成されていてもよい。 The flow path member 3 can be made of an alloy material, for example. The flow path member 3 may be formed of the same material as the metal plate 4.
　流路部材３は、枠体３２及びインターコネクタ３３を有する。枠体３２は、流路３１の側方を取り囲む環状部材である。枠体３２は、金属板４に接合される。インターコネクタ３３は、電解セル１を外部電源又は他の電解セルと電気的に直列に接続する板状部材である。インターコネクタ３３は、枠体３２に接合される。 The flow path member 3 has a frame 32 and an interconnector 33. The frame body 32 is an annular member that surrounds the sides of the flow path 31 . The frame body 32 is joined to the metal plate 4. The interconnector 33 is a plate-like member that electrically connects the electrolytic cell 1 to an external power source or other electrolytic cells in series. The interconnector 33 is joined to the frame 32.
　本実施形態に係る流路部材３では、枠体３２及びインターコネクタ３３が別部材となっているが、枠体３２及びインターコネクタ３３は１つの部材によって構成されていてもよい。 In the flow path member 3 according to the present embodiment, the frame 32 and the interconnector 33 are separate members, but the frame 32 and the interconnector 33 may be composed of one member.
　　［金属板４］
　金属板４は、セル本体部１０を支持する。本実施形態において、金属板４は、板状に形成されている。金属板４は、平板状であってもよいし、曲板状であってもよい。金属板４は、セル１の強度を保つことができればよく、その厚みは特に制限されないが、例えば０．１ｍｍ以上２．０ｍｍ以下とすることができる。 [Metal plate 4]
The metal plate 4 supports the cell main body part 10. In this embodiment, the metal plate 4 is formed into a plate shape. The metal plate 4 may be flat or curved. The thickness of the metal plate 4 is not particularly limited as long as it can maintain the strength of the cell 1, and may be, for example, 0.1 mm or more and 2.0 mm or less.
　金属板４は、第１主面４１、第２主面４２、及び複数の貫通孔４３を有している。金属板４の第１主面４１は、セル本体部１０を支持している。金属板４の第２主面４２は、流路３１と対向している。なお、本実施形態では、金属板４の上面が第１主面４１であり、金属板４の下面が第２主面４２である。金属板４の第２主面４２に流路部材３の枠体３２が接続されている。 The metal plate 4 has a first main surface 41, a second main surface 42, and a plurality of through holes 43. The first main surface 41 of the metal plate 4 supports the cell main body part 10. The second main surface 42 of the metal plate 4 faces the flow path 31. In addition, in this embodiment, the upper surface of the metal plate 4 is the 1st main surface 41, and the lower surface of the metal plate 4 is the 2nd main surface 42. The frame 32 of the channel member 3 is connected to the second main surface 42 of the metal plate 4 .
　図２に示すように、金属板４は、平面視において矩形状である。なお、金属板４は、円形状など他の形状であってもよい。複数の貫通孔４３は、金属板４の長手方向及び短手方向に沿って配列している。複数の貫通孔４３は、金属板４のうち後述する水素極層５に接合される領域に形成されている。貫通孔４３は、第１主面４１に開口している。また、貫通孔４３は、第２主面４２にも開口している。すなわち、貫通孔４３は、金属板４を厚さ方向に貫通している。貫通孔４３は、流路部材３の流路３１と連通している。 As shown in FIG. 2, the metal plate 4 has a rectangular shape in plan view. Note that the metal plate 4 may have other shapes such as a circular shape. The plurality of through holes 43 are arranged along the longitudinal direction and the lateral direction of the metal plate 4. The plurality of through holes 43 are formed in a region of the metal plate 4 that is joined to a hydrogen electrode layer 5, which will be described later. The through hole 43 is open to the first main surface 41 . Furthermore, the through hole 43 is also open to the second main surface 42 . That is, the through hole 43 penetrates the metal plate 4 in the thickness direction. The through hole 43 communicates with the flow path 31 of the flow path member 3.
　貫通孔４３は、平面視において略円形状である。平面視における貫通孔４３の面積は、例えば、０．００００５ｍｍ２以上１ｍｍ２以下とすることができる。また、貫通孔４３の直径は、例えば、１０μｍ以上１０００μｍ以下とすることができる。なお、貫通孔４３は、平面視において矩形状であってもよい。 The through hole 43 has a substantially circular shape in plan view. The area of the through hole 43 in plan view can be, for example, 0.00005 mm 2 or more and 1 mm 2 or less. Further, the diameter of the through hole 43 can be, for example, 10 μm or more and 1000 μm or less. Note that the through hole 43 may have a rectangular shape in plan view.
　流路３１を流れる原料ガスは、貫通孔４３を介して、水素極層５に供給される。この貫通孔４３内にセル本体部１０の一部が入り込んでいる。詳細には、セル本体部１０の水素極層５の一部が貫通孔４３内に入り込んでいる。 The source gas flowing through the flow path 31 is supplied to the hydrogen electrode layer 5 via the through hole 43. A portion of the cell main body 10 is inserted into the through hole 43. Specifically, a part of the hydrogen electrode layer 5 of the cell main body 10 enters into the through hole 43.
　貫通孔４３は、機械加工（例えば、パンチング加工）、レーザ加工、或いは、化学加工（例えば、エッチング加工）などによって形成することができる。金属板４は、ガス透過性を持たせるために、多孔質金属を用いることもできる。 The through hole 43 can be formed by mechanical processing (eg, punching), laser processing, chemical processing (eg, etching), or the like. The metal plate 4 may also be made of porous metal in order to have gas permeability.
　金属板４は、金属材料によって構成されている。例えば、金属板４は、Ｃｒ（クロム）を含有する合金材料によって構成される。このような金属材料としては、Ｆｅ－Ｃｒ系合金鋼（ステンレス鋼など）やＮｉ－Ｃｒ系合金鋼などを用いることができる。金属板４におけるＣｒの含有率は特に制限されないが、４質量％以上３０質量％以下とすることができる。 The metal plate 4 is made of a metal material. For example, the metal plate 4 is made of an alloy material containing Cr (chromium). As such a metal material, Fe--Cr alloy steel (stainless steel, etc.), Ni--Cr alloy steel, etc. can be used. The content of Cr in the metal plate 4 is not particularly limited, but may be 4% by mass or more and 30% by mass or less.
　金属板４は、Ｔｉ（チタン）やＺｒ（ジルコニウム）を含有していてもよい。金属板４におけるＴｉの含有率は特に制限されないが、０．０１ｍｏｌ％以上１．０ｍｏｌ％以下とすることができる。金属板４におけるＺｒの含有率は特に制限されないが、０．０１ｍｏｌ％以上０．４ｍｏｌ％以下とすることができる。金属板４は、ＴｉをＴｉＯ２（チタニア）として含有していてもよいし、ＺｒをＺｒ（ジルコニウム）として含有していてもよい。 The metal plate 4 may contain Ti (titanium) or Zr (zirconium). Although the content rate of Ti in the metal plate 4 is not particularly limited, it can be set to 0.01 mol% or more and 1.0 mol% or less. Although the Zr content in the metal plate 4 is not particularly limited, it can be set to 0.01 mol% or more and 0.4 mol% or less. The metal plate 4 may contain Ti as TiO 2 (titania), or may contain Zr as Zr (zirconium).
　金属板４は、表面に酸化クロム膜を有していてもよい。酸化クロム膜は、金属板４の表面のうち少なくとも一部を覆う。酸化クロム膜は、金属板４の表面のうち少なくとも一部を覆っていればよいが、表面の略全面を覆っていてもよい。また、酸化クロム膜は、貫通孔４３の内壁面を覆っていてもよい。 The metal plate 4 may have a chromium oxide film on its surface. The chromium oxide film covers at least a portion of the surface of the metal plate 4. The chromium oxide film only needs to cover at least a portion of the surface of the metal plate 4, but may cover substantially the entire surface. Further, the chromium oxide film may cover the inner wall surface of the through hole 43.
　酸化クロム膜は、酸化クロムを主成分として含有する。本実施形態において、組成物Ｘが物質Ｙを「主成分として含む」とは、組成物Ｘ全体のうち、物質Ｙが７０重量％以上を占めることを意味する。酸化クロム膜の厚みは特に制限されないが、例えば０．１μｍ以上２０μｍ以下とすることができる。 The chromium oxide film contains chromium oxide as a main component. In this embodiment, composition X "contains substance Y as a main component" means that substance Y accounts for 70% by weight or more of the entire composition X. The thickness of the chromium oxide film is not particularly limited, but may be, for example, 0.1 μm or more and 20 μm or less.
　［セル本体部１０］
　図１に示すように、セル本体部１０は、金属板４の第１主面４１上に配置されている。セル本体部１０は、水素極層５（カソード）、電解質層７、反応防止層８、及び酸素極層９（アノード）を有する。水素極層５、電解質層７、反応防止層８、及び酸素極層９は、この順で金属板４側から積層されている。なお、セル本体部１０は、反応防止層８を有していなくてもよい。また、水素極層５は、本発明の第１電極層の一例であり、酸素極層９は、本発明の第２電極層の一例である。 [Cell body part 10]
As shown in FIG. 1, the cell main body 10 is arranged on the first main surface 41 of the metal plate 4. As shown in FIG. The cell main body 10 includes a hydrogen electrode layer 5 (cathode), an electrolyte layer 7, a reaction prevention layer 8, and an oxygen electrode layer 9 (anode). The hydrogen electrode layer 5, the electrolyte layer 7, the reaction prevention layer 8, and the oxygen electrode layer 9 are laminated in this order from the metal plate 4 side. Note that the cell main body 10 does not need to have the reaction prevention layer 8. Furthermore, the hydrogen electrode layer 5 is an example of the first electrode layer of the invention, and the oxygen electrode layer 9 is an example of the second electrode layer of the invention.
　　［水素極層５］
　水素極層５は、金属板４によって支持される。詳細には、水素極層５は、金属板４の第１主面４１上に配置される。図２に示すように、水素極層５は、金属板４のうち複数の貫通孔４３が設けられた領域を覆うように設けられる。 [Hydrogen pole layer 5]
Hydrogen electrode layer 5 is supported by metal plate 4 . Specifically, the hydrogen electrode layer 5 is arranged on the first main surface 41 of the metal plate 4. As shown in FIG. 2, the hydrogen electrode layer 5 is provided so as to cover a region of the metal plate 4 in which the plurality of through holes 43 are provided.
　図３に示すように、水素極層５は、本体部５１と、複数の充填部５２とを有している。本体部５１は、金属板４の第１主面４１上に配置されている。本体部５１の厚さｔは、例えば、１μｍ以上１００μｍ以下とすることができる。本体部５１は、金属板４よりも薄い。 As shown in FIG. 3, the hydrogen electrode layer 5 has a main body portion 51 and a plurality of filling portions 52. The main body portion 51 is arranged on the first main surface 41 of the metal plate 4. The thickness t of the main body portion 51 can be, for example, 1 μm or more and 100 μm or less. The main body portion 51 is thinner than the metal plate 4.
　充填部５２は、貫通孔４３内に配置されている。充填部５２は、図３に示すように貫通孔４３全体に充填されていてもよいし、図４に示すように貫通孔４３の一部のみに充填されていてもよい。また、図５に示すように、充填部５２は、貫通孔４３から第２主面４２側にはみ出していてもよい。この場合、充填部５２は、第２主面４２と接合していてもよい。充填部５２は、本体部５１と一体的に形成されている。充填部５２の直径は、貫通孔４３の直径と実質的に同じである。 The filling part 52 is arranged within the through hole 43. The filling portion 52 may fill the entire through hole 43 as shown in FIG. 3, or may fill only a part of the through hole 43 as shown in FIG. Further, as shown in FIG. 5, the filling portion 52 may protrude from the through hole 43 toward the second main surface 42 side. In this case, the filling portion 52 may be joined to the second main surface 42. The filling part 52 is formed integrally with the main body part 51. The diameter of the filling part 52 is substantially the same as the diameter of the through hole 43.
　図３に示すように、充填部５２の高さｈは、本体部５１の厚さｔよりも大きい。充填部５２の高さｈは、例えば、１００μｍ以上１０００μｍ以下とすることができる。なお、充填部５２の高さｈとは、図３の上下方向の寸法を意味する。 As shown in FIG. 3, the height h of the filling part 52 is greater than the thickness t of the main body part 51. The height h of the filling portion 52 can be, for example, 100 μm or more and 1000 μm or less. Note that the height h of the filling portion 52 means the dimension in the vertical direction in FIG.
　水素極層５は、複数の第１気孔５３と、複数の第２気孔５４とを有している。第１気孔５３は、本体部５１内に配置される。すなわち、第１気孔５３は、金属板４の第１主面４１に対して、電解質層７側に配置されている。 The hydrogen electrode layer 5 has a plurality of first pores 53 and a plurality of second pores 54. The first pores 53 are arranged within the main body portion 51 . That is, the first pores 53 are arranged on the electrolyte layer 7 side with respect to the first main surface 41 of the metal plate 4.
　第２気孔５４は、充填部５２内に配置されている。すなわち、第２気孔５４は、金属板４の貫通孔４３内に配置されている。 The second pores 54 are arranged within the filling part 52. That is, the second pores 54 are arranged within the through holes 43 of the metal plate 4.
　１つの充填部５２内に複数の第２気孔５４が配置されている。この１つの充填部５２内に配置された複数の第２気孔５４のうち、最も大きい第２気孔５４を最大第２気孔５４と言う。なお、１つの充填部５２内に１つしか第２気孔５４が形成されていない場合、その１つの第２気孔５４が最大第２気孔５４である。 A plurality of second pores 54 are arranged within one filling part 52. Among the plurality of second pores 54 arranged in this one filling part 52, the largest second pore 54 is referred to as the largest second pore 54. Note that when only one second pore 54 is formed in one filling part 52, that one second pore 54 is the maximum second pore 54.
　最大第２気孔５４は、貫通孔４３を画定する内壁面と間隔をあけて配置されている。また、最大第２気孔５４は、充填部５２内において、第２主面４２側に配置されていることが好ましい。なお、最大第２気孔５４は、充填部５２内において、第１主面４１側に配置されていてもよい。また、最大第２気孔５４は、貫通孔４３を画定する内壁面に接触していてもよい。 The largest second pores 54 are spaced apart from the inner wall surface defining the through hole 43. Moreover, it is preferable that the largest second pores 54 are arranged on the second main surface 42 side within the filling part 52 . Note that the largest second pores 54 may be arranged on the first main surface 41 side within the filling part 52. Further, the largest second pores 54 may be in contact with the inner wall surface defining the through hole 43.
　また、本体部５１内に複数の第１気孔５３が配置されている。この本体部５１内に配置された複数の第１気孔５３のうち、最も大きい第１気孔５３を最大第１気孔５３と言う。 Additionally, a plurality of first pores 53 are arranged within the main body portion 51. Among the plurality of first pores 53 arranged in the main body portion 51, the largest first pore 53 is referred to as the largest first pore 53.
　最大第２気孔５４の円相当径は、最大第１気孔５３の円相当径よりも大きい。例えば、最大第２気孔５４の円相当径は、最大第１気孔５３の円相当径の２倍以上とすることができる。また、最大第２気孔５４の円相当径は、最大第１気孔５３の円相当径の８０倍以下とすることができる。なお、好ましくは、１つの充填部５２内に配置される複数の第２気孔５４の円相当径の平均値は、第１気孔５３の円相当径の平均値よりも大きい。 The equivalent circle diameter of the maximum second pores 54 is larger than the equivalent circle diameter of the maximum first pores 53. For example, the maximum equivalent circle diameter of the second pores 54 can be twice or more the equivalent circle diameter of the maximum first pores 53. Further, the maximum equivalent circle diameter of the second pores 54 can be 80 times or less the equivalent circle diameter of the maximum first pores 53. Preferably, the average value of the equivalent circle diameters of the plurality of second pores 54 arranged in one filling part 52 is larger than the average value of the equivalent circle diameters of the first pores 53.
　最大第２気孔５４の円相当径は、以下のようにして測定する。まず、図１のように、貫通孔４３が確認できるように切断面を形成する。この切断面において、貫通孔４３内をＳＥＭ（走査型電子顕微鏡）によって倍率２００で撮影し、そのＳＥＭ写真を画像処理することで、充填部５２内の各第２気孔５４の面積を測定する。そして、最も面積の大きい第２気孔５４を最大第２気孔５４とし、その最大第２気孔５４の面積と同じ面積を有する円の直径を最大第２気孔５４の円相当径とする。 The equivalent circular diameter of the maximum second pores 54 is measured as follows. First, as shown in FIG. 1, a cut surface is formed so that the through hole 43 can be confirmed. At this cut surface, the inside of the through hole 43 is photographed with a SEM (scanning electron microscope) at a magnification of 200, and the SEM photograph is subjected to image processing to measure the area of each second pore 54 in the filling portion 52. The second pore 54 with the largest area is defined as the largest second pore 54, and the diameter of a circle having the same area as the largest second pore 54 is defined as the equivalent circular diameter of the largest second pore 54.
　また、最大第１気孔５３の円相当径は、以下のようにして測定する。まず、セル本体部１０を樹脂埋めし、中央部付近を切断する。機械研磨によって本体部５１を鏡面状態にし、倍率１０００でＳＥＭ写真を２０枚撮影する。そして、各ＳＥＭ写真を画像処理し、その中で最も大きい気孔を最大第１気孔５３とする。そして、その最大第１気孔５３の面積と同じ面積を有する円の直径を最大第１気孔５３の円相当径とする。 Furthermore, the equivalent circular diameter of the maximum first pore 53 is measured as follows. First, the cell main body 10 is filled with resin and cut near the center. The main body portion 51 is brought into a mirror state by mechanical polishing, and 20 SEM photographs are taken at a magnification of 1000. Then, each SEM photograph is subjected to image processing, and the largest pore among them is determined as the largest first pore 53. Then, the diameter of a circle having the same area as the maximum first pore 53 is defined as the circle equivalent diameter of the maximum first pore 53.
　なお、複数の充填部５２のうち、いずれかの充填部５２内に形成された最大第２気孔５４の円相当径が、最大第１気孔５３の円相当径よりも大きければよい。すなわち、各充填部５２内に形成された最大第２気孔５４の円相当径の全てが、最大第１気孔５３の円相当径よりも大きい必要はない。 Note that it is sufficient that the equivalent circle diameter of the maximum second pore 54 formed in any one of the plurality of filling parts 52 is larger than the equivalent circle diameter of the maximum first pore 53. That is, all of the equivalent circle diameters of the maximum second pores 54 formed in each filling portion 52 do not need to be larger than the equivalent circle diameters of the maximum first pores 53.
　好ましくは、複数の充填部５２のうち、１０％以上の充填部５２において、最大第２気孔５４の円相当径が、最大第１気孔５３の円相当径よりも大きい。なお、全ての充填部５２において最大第２気孔５４の円相当径を確認することは困難であるため、例えば、以下のようにして、上記の割合を確認する。まず、任意の１００個の充填部５２のそれぞれにおいて、最大第２気孔５４の円相当径を測定する。そして、その１００個の充填部５２のうち、最大第１気孔５３の円相当径よりも大きい円相当径の最大第２気孔５４を有する充填部５２の割合を確認する。この割合が、１０％以上であることが好ましい。 Preferably, the equivalent circle diameter of the maximum second pores 54 is larger than the equivalent circle diameter of the maximum first pores 53 in 10% or more of the plurality of filling portions 52 . In addition, since it is difficult to confirm the maximum equivalent circle diameter of the second pores 54 in all the filling parts 52, the above ratio is confirmed, for example, as follows. First, the maximum equivalent circle diameter of the second pores 54 in each of the 100 arbitrary filling portions 52 is measured. Then, among the 100 filled portions 52, the ratio of the filled portions 52 having the maximum second pores 54 having an equivalent circle diameter larger than the equivalent circle diameter of the maximum first pores 53 is checked. It is preferable that this ratio is 10% or more.
　最大第２気孔５４の円相当径は、貫通孔４３の直径の１０％以上７０％以下とすることが好ましい。 The maximum equivalent circle diameter of the second pores 54 is preferably 10% or more and 70% or less of the diameter of the through hole 43.
　水素極層５は、多孔質であることが好ましい。水素極層５の気孔率は特に制限されないが、例えば２０％以上７０％以下とすることができる。 It is preferable that the hydrogen electrode layer 5 is porous. Although the porosity of the hydrogen electrode layer 5 is not particularly limited, it can be, for example, 20% or more and 70% or less.
　水素極層５には、貫通孔４３を介して、原料ガスが供給される。原料ガスは、ＣＯ２及びＨ２Ｏを含む。水素極層５は、下記（１）式に示す共電解の電気化学反応に従って、原料ガスから、Ｈ２、ＣＯ、及びＯ２－を生成する。
　・水素極層５：ＣＯ２＋Ｈ２Ｏ＋４ｅ－→ＣＯ＋Ｈ２＋２Ｏ２－・・・（１） Raw material gas is supplied to the hydrogen electrode layer 5 through the through hole 43 . The source gas contains CO 2 and H 2 O. The hydrogen electrode layer 5 generates H 2 , CO, and O 2− from the raw material gas according to the electrochemical reaction of co-electrolysis shown in equation (1) below.
・Hydrogen electrode layer 5: CO 2 +H 2 O+4e - →CO+H 2 +2O 2 -...(1)
　水素極層５は、電子伝導性を有する多孔質材料によって構成される。水素極層５は、酸化物イオン伝導性を有していてよい。水素極層５は、例えば、８ｍｏｌ％イットリア安定化ジルコニア（８ＹＳＺ）、カルシア安定化ジルコニア（ＣＳＺ）、スカンジア安定化ジルコニア（ＳｃＳＺ）、ガドリニウムドープセリア（ＧＤＣ）、サマリウムドープセリア（ＳＤＣ）、（Ｌａ，Ｓｒ）（Ｃｒ，Ｍｎ）Ｏ３、（Ｌａ，Ｓｒ）ＴｉＯ３、Ｓｒ２（Ｆｅ,Ｍｏ）２Ｏ６、（Ｌａ，Ｓｒ）ＶＯ３、（Ｌａ，Ｓｒ）ＦｅＯ３、及びこれらのうち２つ以上を組み合わせた混合材料、或いは、これらのうち１以上とＮｉＯとの複合物によって構成することができる。 The hydrogen electrode layer 5 is made of a porous material having electron conductivity. The hydrogen electrode layer 5 may have oxide ion conductivity. The hydrogen electrode layer 5 is made of, for example, 8 mol% yttria-stabilized zirconia (8YSZ), calcia-stabilized zirconia (CSZ), scandia-stabilized zirconia (ScSZ), gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), (La ,Sr)(Cr, Mn)O3, (La,Sr)TiO3, Sr2(Fe,Mo)2O6 , ( La , Sr) VO3 , (La,Sr) FeO3 , and among these It can be composed of a mixed material combining two or more of them, or a composite of one or more of these and NiO.
　この水素極層５は、以下のようにして形成することができる。まず、本体部５１用のペーストと、充填部５２用のペーストを作製する。本体部５１用のペーストは、上述したいずれかの材料と、有機成分を含有する造孔材と、を含む。充填部５２用のペーストは、本体部５１用のペーストと同様に作製する。なお、充填部５２用のペーストに含まれる造孔材は、本体部５１用のペーストに含まれる造孔剤よりも大きい。 This hydrogen electrode layer 5 can be formed as follows. First, a paste for the main body portion 51 and a paste for the filling portion 52 are prepared. The paste for the main body portion 51 includes any of the above-mentioned materials and a pore-forming material containing an organic component. The paste for the filling part 52 is prepared in the same way as the paste for the main body part 51. Note that the pore-forming material contained in the paste for the filling portion 52 is larger than the pore-forming material contained in the paste for the main body portion 51 .
　次に、充填部５２用のペーストを金属板４の貫通孔４３内にスクリーン印刷し、貫通孔４３内へのペーストの押し込み、及び第１主面４１上からのペーストの除去を兼ねてスキージングする。続いて、本体部５１用のペーストをスクリーン印刷法によって、金属板４の第１主面４１上に形成する。そして、電気炉で加熱することで造孔材を除去することで気孔を形成したのちに焼成する。以上により、金属板４上に水素極層５が形成される。 Next, paste for the filling portion 52 is screen printed into the through hole 43 of the metal plate 4, and squeegeeing is performed to push the paste into the through hole 43 and remove the paste from above the first main surface 41. do. Subsequently, a paste for the main body portion 51 is formed on the first main surface 41 of the metal plate 4 by a screen printing method. Then, the pore-forming material is removed by heating in an electric furnace to form pores, and then fired. Through the above steps, the hydrogen electrode layer 5 is formed on the metal plate 4.
　　［電解質層７］
　図１に示すように、電解質層７は、水素極層５と酸素極層９との間に配置される。本実施形態では、セル本体部１０が反応防止層８を有しているため、電解質層７は、水素極層５と反応防止層８との間に介挿されている。電解質層７の厚さは特に制限されないが、例えば３μｍ以上５０μｍ以下とすることができる。 [Electrolyte layer 7]
As shown in FIG. 1, the electrolyte layer 7 is arranged between the hydrogen electrode layer 5 and the oxygen electrode layer 9. In this embodiment, since the cell main body 10 has the reaction prevention layer 8 , the electrolyte layer 7 is interposed between the hydrogen electrode layer 5 and the reaction prevention layer 8 . The thickness of the electrolyte layer 7 is not particularly limited, but may be, for example, 3 μm or more and 50 μm or less.
　本実施形態において、電解質層７は、水素極層５全体を覆うように配置されている。電解質層７の外周部は、金属板４の第１主面４１に接合されている。これにより、水素極層５側と酸素極層９側との間の気密性を確保できるため、金属板４と電解質層７との間を別途封止する必要がない。 In this embodiment, the electrolyte layer 7 is arranged to cover the entire hydrogen electrode layer 5. The outer peripheral portion of the electrolyte layer 7 is joined to the first main surface 41 of the metal plate 4 . This ensures airtightness between the hydrogen electrode layer 5 side and the oxygen electrode layer 9 side, so there is no need to separately seal between the metal plate 4 and the electrolyte layer 7.
　電解質層７は、水素極層５において生成されたＯ２－を酸素極層９に伝達させる。電解質層７は、酸化物イオン伝導性を有する。電解質層７は、緻密質材料によって構成される。電解質層７の気孔率は、０％以上７％以下程度である。電解質層７は、イオン伝導性を有し且つ電子伝導性を有さない緻密な材料から構成される焼成体である。電解質層７は、例えば、８ＹＳＺ、ＧＤＣ、ＳｃＳＺ、ＳＤＣ、ＬＳＧＭ（ランタンガレート）などによって構成することができる。 The electrolyte layer 7 transmits O 2− generated in the hydrogen electrode layer 5 to the oxygen electrode layer 9. Electrolyte layer 7 has oxide ion conductivity. The electrolyte layer 7 is made of a dense material. The porosity of the electrolyte layer 7 is about 0% or more and 7% or less. The electrolyte layer 7 is a fired body made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte layer 7 can be made of, for example, 8YSZ, GDC, ScSZ, SDC, LSGM (lanthanum gallate), or the like.
　電解質層７の形成方法は特に制限されず、焼成法、スプレーコーティング法、ＰＶＤ法、ＣＶＤ法などにより形成することができる。 The method for forming the electrolyte layer 7 is not particularly limited, and can be formed by a baking method, a spray coating method, a PVD method, a CVD method, or the like.
　　［反応防止層８］
　反応防止層８は、電解質層７上に配置される。反応防止層８は、電解質層７と酸素極層９との間に介挿される。反応防止層８の厚さは特に制限されないが、例えば３μｍ以上５０μｍ以下とすることができる。反応防止層８は、酸素極層９の構成材料と電解質層７の構成材料とが反応して電気抵抗の大きい反応層が形成されることを抑制する。 [Reaction prevention layer 8]
Reaction prevention layer 8 is arranged on electrolyte layer 7 . Reaction prevention layer 8 is interposed between electrolyte layer 7 and oxygen electrode layer 9. The thickness of the reaction prevention layer 8 is not particularly limited, but may be, for example, 3 μm or more and 50 μm or less. The reaction prevention layer 8 prevents the constituent materials of the oxygen electrode layer 9 and the constituent materials of the electrolyte layer 7 from reacting to form a reaction layer with high electrical resistance.
　反応防止層８は、酸化物イオン伝導性を有する材料によって構成される。反応防止層８は、ＧＤＣ、ＳＤＣなどのセリア系材料によって構成することができる。反応防止層８の気孔率は特に制限されないが、例えば０％以上５０％以下とすることができる。反応防止層８の形成方法は特に制限されず、焼成法、スプレーコーティング法、ＰＶＤ法、ＣＶＤ法などにより形成することができる。 The reaction prevention layer 8 is made of a material having oxide ion conductivity. The reaction prevention layer 8 can be made of a ceria-based material such as GDC or SDC. The porosity of the reaction prevention layer 8 is not particularly limited, but may be, for example, 0% or more and 50% or less. The method for forming the reaction prevention layer 8 is not particularly limited, and can be formed by a baking method, a spray coating method, a PVD method, a CVD method, or the like.
　　［酸素極層９］
　酸素極層９は、電解質層７を基準として、水素極層５の反対側に配置される。本実施形態では、セル１が反応防止層８を有しているため、酸素極層９は、反応防止層８上に配置される。 [Oxygen electrode layer 9]
The oxygen electrode layer 9 is arranged on the opposite side of the hydrogen electrode layer 5 with respect to the electrolyte layer 7. In this embodiment, since the cell 1 has the reaction prevention layer 8 , the oxygen electrode layer 9 is arranged on the reaction prevention layer 8 .
　酸素極層９は、多孔質であることが好ましい。酸素極層９の気孔率は特に制限されないが、例えば２０％以上７０％以下とすることができる。酸素極層９の厚さは特に制限されないが、例えば１０μｍ以上１００μｍ以下とすることができる。 The oxygen electrode layer 9 is preferably porous. The porosity of the oxygen electrode layer 9 is not particularly limited, but may be, for example, 20% or more and 70% or less. The thickness of the oxygen electrode layer 9 is not particularly limited, but may be, for example, 10 μm or more and 100 μm or less.
　酸素極層９は、酸化物イオン伝導性及び電子伝導性を有する多孔質材料によって構成される。酸素極層９は、例えば（Ｌａ，Ｓｒ）（Ｃｏ，Ｆｅ）Ｏ３、（Ｌａ，Ｓｒ）ＦｅＯ３、Ｌａ（Ｎｉ，Ｆｅ）Ｏ３、（Ｌａ，Ｓｒ）ＣｏＯ３、及び（Ｓｍ，Ｓｒ）ＣｏＯ３のうち１以上と酸化物イオン伝導材料（ＧＤＣなど）との複合物によって構成することができる。 The oxygen electrode layer 9 is made of a porous material having oxide ion conductivity and electron conductivity. The oxygen electrode layer 9 is made of, for example, (La,Sr)(Co,Fe) O3 , (La,Sr) FeO3 , La(Ni,Fe) O3 , (La,Sr) CoO3 , and (Sm,Sr). ) CoO 3 and an oxide ion conductive material (GDC, etc.).
　酸素極層９の形成方法は特に制限されず、焼成法、スプレーコーティング法、ＰＶＤ法、ＣＶＤ法などにより形成することができる。 The method for forming the oxygen electrode layer 9 is not particularly limited, and can be formed by a baking method, a spray coating method, a PVD method, a CVD method, or the like.
　酸素極層９は、下記（２）式の化学反応に従って、水素極層５から電解質層７を介して伝達されるＯ２－からＯ２を生成する。
　・酸素極層９：２Ｏ２－→Ｏ２＋４ｅ－・・・（２） The oxygen electrode layer 9 generates O 2 from O 2− transmitted from the hydrogen electrode layer 5 via the electrolyte layer 7 according to the chemical reaction of equation (2) below.
・Oxygen electrode layer 9: 2O 2- →O 2 +4e - (2)
　［変形例］
　以上、本発明の実施形態について説明したが、本発明はこれらに限定されるものではなく、本発明の趣旨を逸脱しない限りにおいて種々の変更が可能である。 [Modified example]
Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various changes can be made without departing from the spirit of the present invention.
　（ａ）上記実施形態では、第１電極層の一例として水素極層５、第２電極層の一例として酸素極層９を説明したが、逆であってもよい。すなわち、図６に示すように、第１電極層が酸素極層９であり、第２電極層が水素極層５であってもよい。この場合、酸素極層９が金属板４上に配置される。また、酸素極層９が、本体部９１、充填部９２、第１気孔９３、及び第２気孔９４を有する。また、酸素極層９と電解質層７との間に、反応防止層８を配置する。 (a) In the above embodiment, the hydrogen electrode layer 5 was described as an example of the first electrode layer, and the oxygen electrode layer 9 was described as an example of the second electrode layer, but the reverse may be used. That is, as shown in FIG. 6, the first electrode layer may be the oxygen electrode layer 9, and the second electrode layer may be the hydrogen electrode layer 5. In this case, the oxygen electrode layer 9 is placed on the metal plate 4. Further, the oxygen electrode layer 9 has a main body portion 91 , a filling portion 92 , first pores 93 , and second pores 94 . Further, a reaction prevention layer 8 is disposed between the oxygen electrode layer 9 and the electrolyte layer 7.
　（ｂ）上記実施形態では、電気化学セルの一例として、電解セル１を説明したが、電気化学セルは電解セル以外であってもよい。例えば、固体酸化物系燃料電池などの燃料電池セルであってもよい。この場合、第１電極層を燃料極（アノード）とし、第２電極層を空気極（カソード）とすることができる。 (b) In the above embodiment, the electrolytic cell 1 was described as an example of an electrochemical cell, but the electrochemical cell may be other than an electrolytic cell. For example, it may be a fuel cell such as a solid oxide fuel cell. In this case, the first electrode layer can be used as a fuel electrode (anode), and the second electrode layer can be used as an air electrode (cathode).
１　　：セル
４　　：金属板
４１　　：第１主面
４２　　：第２主面
４３　　：貫通孔
５　　：水素極層
５１　　：本体部
５２　　：充填部
５３　　：第１気孔
５４　　：第２気孔
７　　：電解質層
９　　：酸素極層
１０　：セル本体部 1 : Cell 4 : Metal plate 41 : First main surface 42 : Second main surface 43 : Through hole 5 : Hydrogen electrode layer 51 : Main body part 52 : Filling part 53 : First pore 54 : Second pore 7 : Electrolyte layer 9: Oxygen electrode layer 10: Cell main body

Claims (4)

  1. 　第１電極層、第２電極層、及び前記第１電極層と前記第２電極層との間に配置される電解質層、を有するセル本体部と、
    　第１主面、第２主面、及び貫通孔を有し、前記セル本体部を支持する金属板と、
    を備え、
    　前記第１電極層は、前記金属板の第１主面上に配置される本体部と、前記貫通孔内に配置される充填部と、前記本体部内に配置される少なくとも一つの第１気孔と、前記充填部内に配置される少なくとも一つの第２気孔と、を有し、
    　前記第２気孔のうち最も大きい最大第２気孔の円相当径は、前記第１気孔のうち最も大きい最大第１気孔の円相当径よりも大きい、
    電気化学セル。     a cell main body having a first electrode layer, a second electrode layer, and an electrolyte layer disposed between the first electrode layer and the second electrode layer;
    a metal plate having a first main surface, a second main surface, and a through hole and supporting the cell main body;
    Equipped with
    The first electrode layer includes a main body disposed on the first main surface of the metal plate, a filling part disposed in the through hole, and at least one first pore disposed in the main body. , at least one second pore disposed within the filling part,
    The equivalent circle diameter of the largest maximum second pore among the second pores is larger than the equivalent circle diameter of the largest maximum first pore among the first pores,
    electrochemical cell.
  2. 　前記最大第２気孔は、前記充填部内において、前記第２主面側に配置される、
    請求項１に記載の電気化学セル。     The largest second pores are arranged on the second main surface side in the filling part,
    An electrochemical cell according to claim 1.
  3. 　前記最大第２気孔は、前記貫通孔を画定する内壁面と間隔をあけて配置される、
    請求項１又は２に記載の電気化学セル。     The largest second pore is spaced apart from the inner wall surface defining the through hole.
    The electrochemical cell according to claim 1 or 2.
  4. 　前記最大第２気孔は、前記貫通孔を画定する内壁面に接触する、
    請求項１又は２に記載の電気化学セル。     The largest second pore is in contact with an inner wall surface defining the through hole.
    The electrochemical cell according to claim 1 or 2.
PCT/JP2023/004783 2022-03-14 2023-02-13 Electrochemical cell WO2023176242A1 (en)

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* Cited by examiner, † Cited by third party
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JP2004207088A (en) * 2002-12-26 2004-07-22 Nissan Motor Co Ltd Gas permeable substrate and solid oxide fuel cell using the same
JP2007173243A (en) * 2005-12-21 2007-07-05 Samsung Electro Mech Co Ltd Fuel cell and manufacturing method of the same
JP2008257885A (en) * 2007-03-30 2008-10-23 Dainippon Printing Co Ltd Solid oxide fuel cell
JP2016015308A (en) * 2014-04-01 2016-01-28 ゼネラル・エレクトリック・カンパニイ Interconnection solid-state electrolytic fuel cell device
JP2021158026A (en) * 2020-03-27 2021-10-07 大阪瓦斯株式会社 Metal support for electrochemical element, electrochemical element, electrochemical module, electrochemical device, energy system, solid oxide fuel cell, and solid oxide electrolytic cell

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004207088A (en) * 2002-12-26 2004-07-22 Nissan Motor Co Ltd Gas permeable substrate and solid oxide fuel cell using the same
JP2007173243A (en) * 2005-12-21 2007-07-05 Samsung Electro Mech Co Ltd Fuel cell and manufacturing method of the same
JP2008257885A (en) * 2007-03-30 2008-10-23 Dainippon Printing Co Ltd Solid oxide fuel cell
JP2016015308A (en) * 2014-04-01 2016-01-28 ゼネラル・エレクトリック・カンパニイ Interconnection solid-state electrolytic fuel cell device
JP2021158026A (en) * 2020-03-27 2021-10-07 大阪瓦斯株式会社 Metal support for electrochemical element, electrochemical element, electrochemical module, electrochemical device, energy system, solid oxide fuel cell, and solid oxide electrolytic cell

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