Electrochemical cell

Abstract

An electrochemical cell comprising a metal plate (4), a cell main body, and a first reinforcement part (6). The metal plate (4) has a first main surface (41), a second main surface (42), and a through-hole (43). The cell main body comprises a first electrode layer (5), a second electrode layer (9), and an electrolyte layer (7). The electrolyte layer (7) has been disposed between the first electrode layer (5) and the second electrode layer (9). The cell main body has been disposed on the first main surface (41) of the metal plate (4). The first reinforcement part (6) has been formed on the inner wall surface of the through-hole (43) along the circumferential direction. The first reinforcement part (6) has been constituted so as to reinforce the inner wall surface surrounding the through-hole (43).

Description

Technical Field

[0001] The present invention relates to an electrochemical cell.

Background Art

[0002] In an electrochemical cell such as an electrolytic cell or a fuel cell, a structure in which a cell main 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.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the electrochemical cell configured as described above repeatedly operates and stops, the metal plate repeatedly contracts and expands through a thermal cycle. As a result, there is a problem that the through holes of the metal plate are deformed, and cracks or peeling occur in the electrode layer formed on the through holes.

[0005] Therefore, an object of the present invention is to suppress cracks or peeling of the electrode layer formed on the metal plate.

Means for Solving the Problems

[0006] An electrochemical cell according to an aspect of the present invention includes a metal plate, a cell main body portion, and a first reinforcing portion. The metal plate has a first main surface, a second main surface, and a through hole. The cell main body portion has a first electrode layer, a second electrode layer, and an electrolyte layer. The electrolyte layer is disposed between the first electrode layer and the second electrode layer. The cell main body portion is disposed on the first main surface of the metal plate. The first reinforcing portion is formed along the circumferential direction on the inner wall surface of the through hole. The first reinforcing portion is configured to reinforce the inner wall surface of the through hole.

[0007] According to this configuration, the first reinforcing portion is formed along the circumferential direction on the inner wall surface of the through hole. Therefore, deformation of the through hole can be suppressed. As a result, cracking or peeling of the first electrode layer formed on the metal plate can be suppressed.

[0008] Preferably, the first reinforcing portion is made of a material having a Young's modulus higher than that of the metal plate.

[0009] Preferably, the first reinforcing portion is disposed at an end portion on the second main surface side of the inner wall surface of the through hole.

[0010] Preferably, the first reinforcing portion is annular.

[0011] Preferably, the electrochemical cell further includes a second reinforcing portion. The second reinforcing portion is disposed closer to the first main surface side than the first reinforcing portion. The second reinforcing portion is formed along the circumferential direction on the inner Wall surface of the through hole. The second reinforcing portion is configured to reinforce the inner wall surface of the through hole.

[0012] Preferably, the second reinforcing portion is made of a material having a Young's modulus higher than that of the metal plate.

[0013] Preferably, the first reinforcing portion is made of ceramics.

[0014] Preferably, the first reinforcing portion is made of metal.

Advantages of the Invention

[0015] According to the present invention, cracking or peeling of the electrode layer formed on the metal plate can be suppressed.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an electrolytic cell (an example of an electrochemical cell) according to the present embodiment will be described with reference to the drawings. In the present embodiment, a solid oxide type electrolytic cell (SOEC) will be used as an example of the electrolytic cell for explanation. FIG. 1 is a cross-sectional view showing the electrolytic cell. In the following description, the solid oxide type electrolytic cell may be abbreviated as "cell".

[0018] As shown in FIG. 1, the cell 1 includes a cell main body portion 10, a metal plate 4, and a first reinforcing portion 6. The cell 1 further includes a flow path member 3.

[0019] [Flow path member 3] The flow path member 3 is joined to the metal plate 4. The flow path member 3 has a flow path 31. The flow path 31 is formed on the surface of the flow path member 3 facing the metal plate 4. In the present embodiment, the flow path 31 is formed on the upper surface of the flow path member 3. The flow path 31 opens toward the metal plate 4. The flow path 31 is connected to a manifold (not shown) or the like. In the present embodiment, a raw material gas is supplied to the flow path 31.

[0020] The flow path member 3 can be constituted by, for example, an alloy material. The flow path member 3 may be formed of the same material as the metal plate 4.

[0021] The flow path member 3 has a frame body 32 and an interconnector 33. The frame body 32 is an annular member that surrounds the side 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 in series with an external power source or another electrolytic cell. The interconnector 33 is joined to the frame body 32.

[0022] In the flow path member 3 according to the present embodiment, the frame body 32 and the interconnector 33 are separate members, but the frame body 32 and the interconnector 33 may be constituted by one member.

[0023] [Metal plate 4] The metal plate 4 supports the cell main body portion 10. In the present embodiment, the metal plate 4 is formed in a plate shape. The metal plate 4 may be flat or curved. The metal plate 4 only needs to be able to maintain the strength of the cell 1, and its thickness is not particularly limited, but can be, for example, 0.1 mm or more and 2.0 mm or less.

[0024] 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 portion 10. The second main surface 42 of the metal plate 4 faces the flow path 31. In the present embodiment, the upper surface of the metal plate 4 is the first main surface 41, and the lower surface of the metal plate 4 is the second main surface 42. The frame body 32 of the flow path member 3 is connected to the second main surface 42 of the metal plate 4.

[0025] As shown in Fig. 2, the metal plate 4 is rectangular in plan view. Note that the metal plate 4 may have other shapes such as circular shape. The plurality of through holes 43 are arranged along the longitudinal direction and the short side 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 described later. The through hole 43 opens to the first main surface 41. Further, the through hole 43 also opens to the second main surface 42. That is, the through hole 43 extends in the thickness direction of the metal plate 4 from the first main surface 41 to the second main surface 42 of the metal plate 4. 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 raw material gas flowing through the flow path 31 is supplied to the hydrogen electrode layer 5 through the through hole 43.

[0026] The through hole 43 is substantially circular in plan view. The area of the through hole 43 in plan view is, 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 be rectangular in plan view. Further, the height of the through hole 43 is larger than the thickness of the hydrogen electrode layer 5. The height of the through hole 43 can be, for example, 100 μm or more and 2000 μm or less. Note that the height of the through hole 43 means the dimension in the vertical direction in Fig. 1.

[0027] The through hole 43 can be formed by machining (for example, punching), laser processing, or chemical processing (for example, etching). The metal plate 4 can also be made of a porous metal in order to provide gas permeability.

[0028] 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 (such as stainless steel) or Ni-Cr alloy steel can be used. The content rate of Cr in the metal plate 4 is not particularly limited, but can be 4 mass% or more and 30 mass% or less.

[0029] The metal plate 4 may contain Ti (titanium) or Zr (zirconium). The content rate of Ti in the metal plate 4 is not particularly limited, but can be 0.01 mol% or more and 1.0 mol% or less. The content rate of Zr in the metal plate 4 is not particularly limited, but can be 0.01 mol% or more and 0.4 mol% or less. The metal plate 4 may contain Ti as TiO2 (titanium dioxide), or may contain Zr as ZrO2 (zirconia).

[0030] The metal plate 4 may have an oxide film on its surface. Specifically, the metal plate 4 may have a chromium oxide film on its surface. The oxide film covers at least a part of the surface of the metal plate 4. The oxide film only needs to cover at least a part of the surface of the metal plate 4, but may cover substantially the entire surface. Also, the oxide film may cover the inner wall surface of the through-hole 43. The thickness of the oxide film is not particularly limited, but can be, for example, 0.1 μm or more and 20 μm or less.

[0031] [Cell main body 10] As shown in FIG. 1, the cell main body 10 is disposed on the first main surface 41 of the metal plate 4. The cell main body 10 has 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 may not have the reaction prevention layer 8. Also, the hydrogen electrode layer 5 is an example of the first electrode layer of the present invention, and the oxygen electrode layer 9 is an example of the second electrode layer of the present invention.

[0032] [Hydrogen electrode layer 5] The hydrogen electrode layer 5 is supported by the metal plate 4. Specifically, the hydrogen electrode layer 5 is disposed on the first main surface 41 of the metal plate 4. The thickness t of the hydrogen electrode layer 5 can be, for example, 1 μm or more and 100 μm or less. The hydrogen electrode layer 5 is thinner than 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 where a plurality of through-holes 43 are provided.

[0033] The hydrogen electrode layer 5 is preferably porous. The porosity of the hydrogen electrode layer 5 is not particularly limited, and can be, for example, 20% or more and 70% or less.

[0034] The hydrogen electrode layer 5 is composed of a porous material having electron conductivity. The hydrogen electrode layer 5 may have oxide ion conductivity. The hydrogen electrode layer 5 can be composed 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, a mixed material combining two or more of these, or a composite of one or more of these and NiO.

[0035] The method for forming the hydrogen electrode layer 5 is not particularly limited, and it can be formed by a firing method, a spray coating method, a PVD method, a CVD method, etc.

[0036] A raw material gas is supplied to the hydrogen electrode layer 5 through the through-hole 43. The raw material gas contains CO2 and H2O. The hydrogen electrode layer 5 generates H2, CO, and O from the raw material gas according to the electrochemical reaction of co-electrolysis shown in the following formula (1). 2- to generate. ·Hydrogen electrode layer 5: CO2 + H2O + 4e - → CO + H2 + 2O 2- ···(1)

[0037] [Electrolyte layer 7] As shown in FIG. 1, the electrolyte layer 7 is disposed 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 inserted between the hydrogen electrode layer 5 and the reaction prevention layer 8. The thickness of the electrolyte layer 7 is not particularly limited, and can be, for example, 3 μm or more and 50 μm or less.

[0038] 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. Thereby, since airtightness between the hydrogen electrode layer 5 side and the oxygen electrode layer 9 side can be ensured, it is not necessary to separately seal between the metal plate 4 and the electrolyte layer 7.

[0039] The electrolyte layer 7 transmits O 2- generated in the hydrogen electrode layer 5 to the oxygen electrode layer 9. The electrolyte layer 7 has oxide ion conductivity. The electrolyte layer 7 is composed 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 composed of a dense material having ion conductivity and no electron conductivity. The electrolyte layer 7 can be composed of, for example, 8YSZ, GDC, ScSZ, SDC, LSGM (lanthanum gallate), etc.

[0040] The method for forming the electrolyte layer 7 is not particularly limited, and it can be formed by a firing method, a spray coating method, a PVD method, a CVD method, etc.

[0041] [Reaction prevention layer 8] The reaction prevention layer 8 is arranged on the electrolyte layer 7. The reaction prevention layer 8 is inserted between the electrolyte layer 7 and the oxygen electrode layer 9. The thickness of the reaction prevention layer 8 is not particularly limited, but can be, for example, 3 μm or more and 50 μm or less. The reaction prevention layer 8 suppresses the reaction between the constituent material of the oxygen electrode layer 9 and the constituent material of the electrolyte layer 7 to form a reaction layer with high electrical resistance.

[0042] The reaction prevention layer 8 is composed of a material having oxide ion conductivity. The reaction prevention layer 8 can be composed of a ceria-based material such as GDC, SDC, etc. The porosity of the reaction prevention layer 8 is not particularly limited, but can be, for example, 0% or more and 50% or less. The method for forming the reaction prevention layer 8 is not particularly limited, and it can be formed by a firing method, a spray coating method, a PVD method, a CVD method, etc.

[0043] [Oxygen electrode layer 9] The oxygen electrode layer 9 is disposed on the side opposite to the hydrogen electrode layer 5 with respect to the electrolyte layer 7. In the present embodiment, since the cell 1 has the reaction prevention layer 8, the oxygen electrode layer 9 is disposed on the reaction prevention layer 8.

[0044] The oxygen electrode layer 9 is preferably porous. The porosity of the oxygen electrode layer 9 is not particularly limited, but can be, for example, 20% or more and 70% or less. The thickness of the oxygen electrode layer 9 is not particularly limited, but can be, for example, 10 μm or more and 100 μm or less.

[0045] The oxygen electrode layer 9 is composed of a porous material having oxide ion conductivity and electron conductivity. The oxygen electrode layer 9 can be composed of, for example, a composite of one or more of (La,Sr)(Co,Fe)O3, (La,Sr)FeO3, La(Ni,Fe)O3, (La,Sr)CoO3, and (Sm,Sr)CoO3 and an oxide ion conducting material (such as GDC).

[0046] The method for forming the oxygen electrode layer 9 is not particularly limited, and it can be formed by a firing method, a spray coating method, a PVD method, a CVD method, or the like.

[0047] The oxygen electrode layer 9 generates O2 from O transmitted from the hydrogen electrode layer 5 through the electrolyte layer 7 according to the chemical reaction of the following formula (2). 2- to generate O2. · Oxygen electrode layer 9: 2O 2- → O2 + 4e - ··· (2)

[0048] [First reinforcing portion 6] FIG. 3 is a cross-sectional view showing details around the through-hole, and FIG. 4 is a bottom view of the through-hole as seen from the second main surface side. As shown in FIGS. 3 and 4, the first reinforcing portion 6 is formed along the circumferential direction on the inner wall surface of the through-hole 43. Specifically, the first reinforcing portion 6 is annular. That is, the first reinforcing portion 6 extends continuously along the circumferential direction. Note that the first reinforcing portion 6 may extend intermittently along the circumferential direction. Note that the first reinforcing portion 6 does not necessarily need to be formed directly on the inner wall surface of the through-hole 43. For example, when an oxide film is formed on the inner wall surface of the through-hole 43, the first reinforcing portion 6 is formed on the oxide film.

[0049] The first reinforcing portion 6 is disposed at the end portion on the second main surface 42 side of the inner wall surface of the through-hole 43. Specifically, the through-hole 43 has an end portion on the first main surface 41 side and an end portion on the second main surface 42 side in the axial direction. And the first reinforcing portion 6 is not formed at the end portion on the first main surface 41 side among both end portions in the axial direction of the through-hole 43, but is formed at the end portion on the second main surface 42 side. Note that the first reinforcing portion 6 may be disposed on the first main surface 41 side.

[0050] The first reinforcing portion 6 protrudes from the inner wall surface of the through-hole 43 toward the center. The height of the first reinforcing portion 6 is, for example, 1 μm or more and 100 μm or less. Note that the height of the first reinforcing portion 6 is the dimension from the inner wall surface of the through-hole 43 toward the center.

[0051] The first reinforcing portion 6 is made of a material having a higher Young's modulus than the metal plate 4. For example, the first reinforcing portion 6 is made of ceramics such as an oxide. More specifically, the first reinforcing portion 6 can be made of chromium oxide, iron oxide, manganese oxide, and composite oxides thereof, crystallized glass, YSZ, or GDC.

[0052] Note that the first reinforcing portion 6 may be made of the same material as the oxide film formed on the inner wall surface of the through-hole 43. In this case, the portion protruding with respect to the other portions is the first reinforcing portion 6. That is, the height of the first reinforcing portion 6 is larger than the thickness of the oxide film. Also, the height of the first reinforcing portion 6 in this case is the height from the inner wall surface of the through-hole 43.

[0053] Further, the first reinforcing portion 6 may be made of metal. For example, the first reinforcing portion 6 can be made of nickel, iron, cobalt, copper, or an alloy thereof.

[0054] The first reinforcing portion 6 can be formed by applying a reinforcing material paste along the circumferential direction on the inner wall surface of the through hole 43 by a precision nozzle dispenser and firing the reinforcing material paste. In addition, the first reinforcing portion 6 can also be formed by locally laser-heating the inner wall surface of the through hole 43 along the circumferential direction to form a thick oxide film.

[0055] Note that the first reinforcing portion 6 is preferably formed in all the through holes 43, but it is not necessary to be formed in all the through holes 43. For example, the first reinforcing portion 6 is preferably formed in 50% or more of the through holes 43. Note that the first reinforcing portion 6 is preferably formed in at least 10% or more of the through holes 43.

[0056] [Modification Example] As described above, the embodiments of the present invention have been described, but the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0057] (a) In the above embodiment, the hydrogen electrode layer 5 was disposed on the metal plate 4, but the configuration of the cell main body portion 10 is not limited thereto. For example, as shown in FIG. 5, the oxygen electrode layer 9 may be disposed on the metal plate 4. In this case, the oxygen electrode layer 9, the reaction prevention layer 8, the electrolyte layer 7, and the hydrogen electrode layer 5 are disposed in this order from the metal plate 4 side. The electrolyte layer 7 is formed so as to cover the oxygen electrode layer 9 and the reaction prevention layer 8. Note that the reaction prevention layer 8 may not be formed.

[0058] (b) As shown in FIG. 6, the hydrogen electrode layer 5 may enter into the through-hole 43. In this case, the hydrogen electrode layer 5 may be filled only in a part of the through-hole 43 as shown in FIG. 6, may be filled in the whole of the through-hole 43, or may protrude from the through-hole 43 to the second main surface 42 side.

[0059] (c) As shown in FIG. 7, the electrolytic cell 1 may further have a second reinforcing portion 61. The second reinforcing portion 61 is disposed on the first main surface 41 side rather than the first reinforcing portion 6. For example, the second reinforcing portion 61 is disposed at the central portion in the axial direction of the through-hole 43. The second reinforcing portion 61 is disposed at a distance from the hydrogen electrode layer 5. Also, the second reinforcing portion 61 is disposed at a distance from the first reinforcing portion 6.

[0060] The second reinforcing portion 61, similar to the first reinforcing portion 6, is formed along the circumferential direction on the inner Wall surface of the through-hole 43. The height of the second reinforcing portion 61 may be formed lower than the height of the first reinforcing portion 6. Also, the second reinforcing portion 61 is composed of a material having a higher Young's modulus than the metal plate 4. The second reinforcing portion 61 can be composed of the same material as the first reinforcing portion 6. Also, the second reinforcing portion 61 can be formed in the same manner as the first reinforcing portion 6.

[0061] (d) In the above embodiment, the first reinforcing portion 6 is disposed at the end portion on the second main surface 42 side of the through-hole 43, but the position of the first reinforcing portion 6 is not limited thereto. For example, the first reinforcing portion 6 may be disposed at the central portion in the axial direction of the through-hole 43, or may be disposed at other positions.

[0062] (e) In the above embodiment, the first reinforcing portion 6 is not disposed on the second main surface 42 of the metal plate 4, but the configuration of the first reinforcing portion 6 is not limited thereto. For example, as shown in FIG. 8, the first reinforcing portion 6 may be formed on the inner wall surface of the through-hole 43 and also on the second main surface 42. In this case, the first reinforcing portion 6 is disposed so as to cover the corner portion 421 formed by the inner wall surface of the through-hole 43 and the second main surface 42.

[0063] (f) In the above-described embodiment, the electrolytic cell 1 has been 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).

Explanation of Signs

[0064] 1: Electrolytic cell 4: Metal plate 41: First main surface 42: Second main surface 43: Through hole 5: Hydrogen electrode layer 6: First reinforcing portion 61: Second reinforcing portion 7: Electrolyte layer 9: Oxygen electrode layer 10: Cell main body portion

Claims

1. A metal plate having a first main surface, a second main surface, and a through hole, A cell body portion disposed on the first main surface of the metal plate, 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 first reinforcing portion formed along the circumferential direction on the inner wall surface of the through hole and configured to reinforce the inner wall surface of the through hole; Comprising: The first reinforcing portion protrudes from the inner wall surface of the through hole toward the center and is disposed at an end portion on the second main surface side of the inner wall surface of the through hole. The first reinforcing portion is annular. The first reinforcing portion is made of a material having a higher Young's modulus than the metal plate. An electrochemical cell.

2. The metal plate has an oxide film covering the inner wall surface of the through hole, The first reinforcing portion is disposed on the oxide film. The electrochemical cell according to claim 1.

3. The first reinforcing portion contains components different from those of the oxide film. The electrochemical cell according to claim 2.

4. The first main surface of the metal plate is connected to the inner wall surface of the through hole without an intervening curved surface. The electrochemical cell according to claim 1.

5. Further comprising a second reinforcing portion disposed on the first main surface side of the first reinforcing portion, formed along the circumferential direction on the inner wall surface of the through hole, and configured to reinforce the inner wall surface of the through hole. The electrochemical cell according to claim 1.

6. The second reinforcing portion is made of a material having a higher Young's modulus than the metal plate. The electrochemical cell according to claim 5.

7. The height of the second reinforcing part is lower than the height of the first reinforcing part. The electrochemical cell according to claim 5.

8. The first reinforcing part is made of ceramics. The electrochemical cell according to claim 1.

9. The first reinforcing part is made of metal. The electrochemical cell according to claim 1.

10. A metal plate having a first main surface, a second main surface, and a through hole, A cell body portion disposed on the first main surface of the metal plate, 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 first reinforcing part formed along the circumferential direction on the inner wall surface of the through hole and configured to reinforce the inner wall surface of the through hole, A second reinforcing part disposed closer to the first main surface side than the first reinforcing part, formed along the circumferential direction on the inner wall surface of the through hole, and configured to reinforce the inner wall surface of the through hole, Comprising The first reinforcing part is annular. The first reinforcing part is made of a material having a higher Young's modulus than the metal plate. Electrochemical cell.

Images