Electrochemical Cell

Abstract

An electrolyte layer (7) comprises an inner part (71), an outer part (72) and a middle part (73). The inner part (71) covers the surface of a hydrogen electrode layer (6) and is estranged from the tip (P6) of the hydrogen electrode layer (6) in the surface direction by at least a set distance (D1). The outer part (72) covers approximately all of a region of a first main surface (20S) that is exposed from the hydrogen electrode layer (6) and is estranged from the tip (P6) of the hydrogen electrode layer (6) in the surface direction by at least the set distance (D1). The middle part (73) lies between the inner part (71) and the outer part (72), in the surface direction. The average thickness of the middle part (73) is greater than the average thickness of the inner part (71).

Description

[Technical field]

[0001] The present invention relates to electrochemical cells. [Background technology]

[0002] In electrochemical cells (electrolysis cells, fuel cells, etc.), a structure in which a cell body is supported by a metal support is known. For example, the electrochemical cell described in Patent Document 1 includes a cell body in which a first electrode layer, an electrolyte layer, and a second electrode layer are laminated in this order on a main surface of a metal support. The electrolyte layer covers the first electrode layer, and an end of the electrolyte layer is connected to the main surface of the cell body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2020-155337 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the electrochemical cell described in Patent Document 1, the outer periphery of the metal support is exposed from the electrolyte layer, and therefore the rigidity of the outer periphery of the electrochemical cell depends solely on the rigidity of the metal support.

[0005] An object of the present invention is to provide an electrochemical cell capable of improving rigidity. [Means for solving the problem]

[0006] An electrochemical cell according to a first aspect of the present invention includes a metal support having a plurality of supply holes formed on a main surface, a first electrode layer formed on the main surface and covering the plurality of supply holes, a second electrode layer, and a cell body having an electrolyte layer disposed between the first and second electrode layers. In a cross section perpendicular to the main surface, the electrolyte layer has an inner portion covering the surface of the first electrode layer and spaced a predetermined distance or more from a tip of the first electrode layer in a planar direction parallel to the main surface, an outer portion covering substantially the entire area of ​​the main surface of the metal support that is exposed from the first electrode layer and spaced a predetermined distance or more from the tip of the first electrode layer in the planar direction, and a middle portion sandwiched between the inner portion and the outer portion in the planar direction. The average thickness of the middle portion is greater than the average thickness of the inner portion.

[0007] An electrochemical cell according to a second aspect of the present invention is the electrochemical cell according to the first aspect, wherein the average thickness of the middle portion is greater than the average thickness of the outer portion.

[0008] An electrochemical cell according to a third aspect of the present invention is related to the first or second aspect, wherein the predetermined distance is half the thickness of the metal support.

[0009] An electrochemical cell according to a fourth aspect of the present invention relates to any of the first to third aspects, and the average thickness of the intermediate portion is the average thickness of the three locations that divide the intermediate portion into four equal parts in the surface direction, and the average thickness of the inner portion is the average thickness of the three locations that divide the portion of the inner portion up to a predetermined distance from the intermediate portion in the surface direction into four equal parts.

[0010] An electrochemical cell according to a fifth aspect of the present invention relates to any of the second to fourth aspects, wherein the average thickness of the intermediate portion is the average value of thicknesses at three locations that divide the intermediate portion into four equal parts in the surface direction, and the average thickness of the outer portion is the average value of thicknesses at three locations that divide the outer portion into four equal parts in the surface direction.

[0011] An electrochemical cell according to a sixth aspect of the present invention relates to any one of the first to fifth aspects, wherein the first electrode layer has a side surface formed along a thickness direction perpendicular to the surface direction, and the side surface is uneven. Effect of the Invention

[0012] According to the present invention, it is possible to provide an electrochemical cell capable of improving rigidity. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view of an electrolysis cell according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA of FIG. [Diagram 3] FIG. 3 is a partially enlarged view of FIG. [Figure 4] FIG. 4 is a cross-sectional view of an electrolysis cell according to the first modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] (Electrolysis cell 1) Fig. 1 is a plan view of an electrolysis cell 1 according to an embodiment. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. The electrolysis cell 1 is an example of the "electrochemical cell" according to the present invention.

[0015] The electrolysis cell 1 is formed in a plate shape extending in the X-axis and Y-axis directions. In this embodiment, the electrolysis cell 1 is formed in a rectangular shape extending in the Y-axis direction in a plan view. However, the planar shape of the electrolysis cell 1 is not particularly limited, and may be a polygon other than a rectangle, an ellipse, a circle, or the like.

[0016] As shown in FIG. 2, the electrolysis cell 1 includes a cell main body 10, a metal support 20, and a flow path member 30.

[0017] [Cell body 10] The cell main body 10 has a hydrogen electrode layer 6 (cathode), an electrolyte layer 7, a reaction prevention layer 8, and an oxygen electrode layer 9 (anode). The hydrogen electrode layer 6, electrolyte layer 7, reaction prevention layer 8, and oxygen electrode layer 9 are laminated in this order from the metal support 20 side in the Z-axis direction perpendicular to the X-axis direction and the Y-axis direction. The hydrogen electrode layer 6, electrolyte layer 7, and oxygen electrode layer 9 are essential components, while the reaction prevention layer 8 is optional.

[0018] [Hydrogen electrode layer 6] The hydrogen electrode layer 6 is disposed between the metal support 20 and the electrolyte layer 7. The hydrogen electrode layer 6 is supported by the metal support 20. In detail, the hydrogen electrode layer 6 is disposed on the first main surface 20S of the metal support 20. The hydrogen electrode layer 6 covers a plurality of supply holes 21 formed in the first main surface 20S of the metal support 20. A portion of the hydrogen electrode layer 6 may extend into each supply hole 21. The hydrogen electrode layer 6 is an example of a "first electrode layer" according to the present invention.

[0019] A source gas is supplied to the hydrogen electrode 6 through each supply hole 21. The source gas contains at least H2O.

[0020] When the raw material gas contains only H2O, the hydrogen electrode 6 produces H2 from the raw material gas in accordance with the electrochemical reaction of water electrolysis shown in the following formula (1). Hydrogen electrode 6: H2O+2e - →H2+O 2- (1)

[0021] When the raw gas contains CO in addition to H2O, the hydrogen electrode 6 converts the raw gas into H2, CO, and O2 in accordance with the electrochemical reactions of co-electrolysis shown in the following formulas (2), (3), and (4). 2- Generate. Hydrogen electrode 6: CO2+H2O+4e - →CO+H2+2O 2- (2) Electrochemical reaction of H2O: H2O+2e - →H2+O 2- (3) Electrochemical reaction of CO2: CO2+2e - →CO+O 2- (4)

[0022] The hydrogen electrode layer 6 is made of a porous material having electronic conductivity. The hydrogen electrode layer 6 may have oxide ion conductivity. The hydrogen electrode layer 6 may be 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, a mixed material of two or more of these, or a composite of one or more of these and NiO.

[0023] The value of the thermal expansion coefficient of the hydrogen electrode layer 6 is not particularly limited. For example, ―6 / ℃ or more 20×10 -6 / °C or less.

[0024] The porosity of the hydrogen electrode layer 6 is not particularly limited, but may be, for example, 5% to 70%. The thickness of the hydrogen electrode layer 6 is not particularly limited, but may be, for example, 1 μm to 100 μm.

[0025] The method for forming the hydrogen electrode layer 6 is not particularly limited, and may be a firing method, a spray coating method (such as a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method.

[0026] [Electrolyte layer 7] The electrolyte layer 7 is disposed between the hydrogen electrode layer 6 and the oxygen electrode layer 9. In this embodiment, the reaction prevention layer 8 is disposed between the electrolyte layer 7 and the oxygen electrode layer 9, and therefore the electrolyte layer 7 is disposed between the hydrogen electrode layer 6 and the reaction prevention layer 8 and is connected to both the hydrogen electrode layer 6 and the reaction prevention layer 8.

[0027] The electrolyte layer 7 covers the hydrogen electrode layer 6 and also covers the region of the first main surface 20S of the metal support 20 that is exposed from the hydrogen electrode layer 6. As shown in Fig. 1, the electrolyte layer 7 covers the entire surface of the hydrogen electrode layer 6 in a plan view. As shown in Fig. 1, the electrolyte layer 7 preferably covers the entire region of the first main surface 20S that is exposed from the hydrogen electrode layer 6 in a plan view, but a part of the first main surface 20S may be exposed from the electrolyte layer 7. A detailed configuration of the electrolyte layer 7 will be described later.

[0028] The electrolyte layer 7 is formed by discharging the O 2- to the oxygen electrode layer 9. The electrolyte layer 7 is made of a dense material having oxide ion conductivity. The electrolyte layer 7 can be made of, for example, YSZ (yttria-stabilized zirconia, e.g., 8YSZ), GDC (gadolinium-doped ceria), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), LSGM (lanthanum gallate), or the like.

[0029] The value of the thermal expansion coefficient of the electrolyte layer 7 is not particularly limited, but is, for example, 10×10 ―6 / ℃ or more 12×10 ―6 / °C or less.

[0030] The porosity of the electrolyte layer 7 is not particularly limited, but may be, for example, 0.1% to 7%. The thickness of the electrolyte layer 7 is not particularly limited, but may be, for example, 1 μm to 100 μm.

[0031] The method for forming the electrolyte layer 7 is not particularly limited, and a baking method, a spray coating method, a PVD method, a CVD method, or the like can be used.

[0032] [Reaction prevention layer 8] The reaction prevention layer 8 is disposed between the electrolyte layer 7 and the oxygen electrode layer 9. The reaction prevention layer 8 is disposed on the opposite side of the electrolyte layer 7 to the hydrogen electrode layer 6. The reaction prevention layer 8 prevents the constituent elements of the electrolyte layer 7 from reacting with the constituent elements of the oxygen electrode layer 9 to form a layer with high electrical resistance.

[0033] The reaction prevention layer 8 is made of an oxide ion conductive material, and may be made of GDC, SDC, or the like.

[0034] The porosity of the reaction prevention layer 8 is not particularly limited, but may be, for example, 0.1% to 50%. The thickness of the reaction prevention layer 8 is not particularly limited, but may be, for example, 1 μm to 50 μm.

[0035] The method for forming the reaction prevention layer 8 is not particularly limited, and a baking method, a spray coating method, a PVD method, a CVD method, or the like can be used.

[0036] [Oxygen electrode layer 9] The oxygen electrode layer 9 is disposed on the opposite side of the hydrogen electrode layer 6 with respect to the electrolyte layer 7. In this embodiment, the reaction prevention layer 8 is disposed between the electrolyte layer 7 and the oxygen electrode layer 9, and therefore the oxygen electrode layer 9 is connected to the reaction prevention layer 8. If the reaction prevention layer 8 is not disposed between the electrolyte layer 7 and the oxygen electrode layer 9, the oxygen electrode layer 9 is connected to the electrolyte layer 7. The oxygen electrode layer 9 is an example of a "second electrode layer" according to the present invention.

[0037] The oxygen electrode layer 9 reacts with O 2 transferred from the hydrogen electrode layer 6 through the electrolyte layer 7 in accordance with the chemical reaction of the following formula (2): 2- produces O2 from Oxygen electrode layer 9:2O 2- →O2+4e - (2)

[0038] The oxygen electrode layer 9 is made of a porous material having oxide ion conductivity and electron conductivity. The oxygen electrode layer 9 can be made of a composite material 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 conductive material (such as GDC).

[0039] The porosity of the oxygen electrode layer 9 is not particularly limited, but may be, for example, 20% to 60%. The thickness of the oxygen electrode layer 9 is not particularly limited, but may be, for example, 1 μm to 100 μm.

[0040] The method for forming the oxygen electrode layer 9 is not particularly limited, and a baking method, a spray coating method, a PVD method, a CVD method, or the like can be used.

[0041] [Metal support 20] The metal support 20 supports the cell main body 10. The metal support 20 is formed in a plate shape. The metal support 20 may be in a flat plate shape or a curved plate shape. The metal support 20 may have any thickness as long as it can maintain the strength of the electrolysis cell 1, and the thickness is not particularly limited, but may be, for example, 0.1 mm or more and 2.0 mm or less.

[0042] 2, the metal support 20 has a plurality of supply holes 21, a first main surface 20S and a second main surface 20T. The first main surface 20S is an example of the "main surface" according to the present invention.

[0043] Each supply hole 21 is formed in the first main surface 20S. Each supply hole 21 penetrates the metal support 20 from the first main surface 20S to the second main surface 20T. Each supply hole 21 opens to each of the first main surface 20S and the second main surface 20T. The opening of each supply hole 21 in the first main surface 20S is covered by the hydrogen electrode layer 6. That is, each supply hole 21 is formed in a region of the first main surface 20S that is joined to the hydrogen electrode layer 6. Each supply hole 21 is connected to a flow path 30a between the metal support 20 and the flow path member 30.

[0044] Each supply hole 21 can be formed by mechanical processing (e.g., punching), laser processing, chemical processing (e.g., etching), or the like. When the metal support 20 is made of a porous metal, each supply hole 21 may be an open hole of the porous metal. Each supply hole 21 may be perpendicular to the first main surface 20S, or may not be perpendicular to the first main surface 20S, and may not be linear.

[0045] The cell main body 10 is joined to the first main surface 20S. The flow path member 30 is joined to the second main surface 20T. The first main surface 20S is provided on the opposite side to the second main surface 20T.

[0046] The metal support 20 is made of a metal material. For example, the metal support 20 is made of an alloy material containing Cr (chromium). Examples of such metal materials include Fe-Cr alloy steel (stainless steel, etc.) and Ni-Cr alloy steel. The Cr content in the metal support 20 is not particularly limited, but may be 4% by mass or more and 30% by mass or less.

[0047] The metal support 20 may contain Ti (titanium) and / or Zr (zirconium). The Ti content in the metal support 20 is not particularly limited, but may be 0.01 mol% or more and 1.0 mol% or less. The Al content in the metal support 20 is not particularly limited, but may be 0.01 mol% or more and 0.4 mol% or less. The metal support 20 may contain Ti as TiO2 (titania) and Zr as ZrO2 (zirconia).

[0048] The thermal expansion coefficient of the metal support 20 is not particularly limited. For example, ―6 / ℃ or more 20×10 ―6 / °C or less.

[0049] The metal support 20 may have an oxide film on its surface, which is formed by oxidation of the constituent elements of the metal support 20. A typical example of the oxide film is a chromium oxide film. The chromium oxide film covers at least a part of the surface of the metal support 20. The chromium oxide film may also cover at least a part of the inner wall surface of each supply hole 21.

[0050] [Flow path member 30] The flow path member 30 is joined to the second main surface 20T of the metal support 20. A flow path 30a is formed between the flow path member 30 and the metal support 20. A source gas is supplied to the flow path 30a. The source gas supplied to the flow path 30a is supplied to the hydrogen electrode layer 6 of the cell main body 10 through each supply hole 21 of the metal support 20.

[0051] The flow path member 30 can be made of, for example, an alloy material. The flow path member 30 may be formed of the same material as the metal support 20. In this case, the flow path member 30 may be substantially integral with the metal support 20.

[0052] The flow path member 30 has a frame 31 and an interconnector 32. The frame 31 is an annular member that surrounds the side of the flow path 30a. The frame 31 is joined to the second main surface 20T of the metal support 20. The interconnector 32 is a plate-like member for electrically connecting an external power source or another electrolysis cell to the electrolysis cell 1 in series. The interconnector 32 is joined to the frame 31.

[0053] In this embodiment, the frame 31 and the interconnector 32 are separate members, but the frame 31 and the interconnector 32 may be an integrated member.

[0054] [Configuration of electrolyte layer 7] Fig. 3 is a partially enlarged view of Fig. 2. Fig. 3 is a cross section perpendicular to the first main surface 20S of the metal support 20. In Fig. 3, a cross section of the outer periphery of the electrolysis cell 1 is shown.

[0055] 3, the electrolyte layer 7 has an inner portion 71, an outer portion 72, and an intermediate portion 73. In a planar direction parallel to the first main surface 20S of the metal support 20 (the X-axis direction shown in FIG. 3), the inner portion 71 is surrounded by the intermediate portion 73, and the intermediate portion 73 is surrounded by the outer portion 72.

[0056] The inner portion 71 covers the surface of the hydrogen electrode layer 6 and is separated in the planar direction by a predetermined distance D1 or more from the tip P6 of the hydrogen electrode layer 6. The inner portion 71 is a portion of the electrolyte layer 7 that is on the first reference line L1 and is located inside the first reference line L1. In this specification, the inner portion means the side from the tip P20 of the first main surface 20S toward the tip P6 of the hydrogen electrode layer 6 in the planar direction.

[0057] The first reference line L1 is a straight line that is parallel to the second reference line L2 and is set a predetermined distance D1 inward from the second reference line L2. The second reference line L2 is a straight line that passes through the tip P6 of the hydrogen electrode layer 6 and is perpendicular to the first main surface 20S. The predetermined distance D1 is half the thickness Ta of the metal support 20 on the second reference line L2. The reason for defining the predetermined distance D1 based on the thickness Ta of the metal support 20 is to identify the portion adjacent to the tip P6 of the hydrogen electrode layer 6 as the intermediate portion 73.

[0058] When defining the second reference line L2, a straight line obtained by linearizing the first main surface 20S on a cross-sectional image (e.g., an SEM image) using the least squares method is used as the first main surface 20S. In addition, although the tip P6 of the hydrogen electrode layer 6 is located on the first main surface 20S in Fig. 3, the tip P6 of the hydrogen electrode layer 6 may be separated from the first main surface 20S.

[0059] The outer portion 72 covers substantially the entire region of the first main surface 20S exposed from the hydrogen electrode layer 6, and is at least a predetermined distance D1 away from the tip P6 of the hydrogen electrode layer 6 in the planar direction. Covering substantially the entire region of the first main surface 20S exposed from the hydrogen electrode layer 6 means that the outer portion 72 covers up to the tip P20 of the first main surface 20S. The outer portion 72 is a portion of the electrolyte layer 7 on the third reference line L3 and outside the third reference line L3. In this specification, the outside means the side from the tip P6 of the hydrogen electrode layer 6 toward the tip P20 of the first main surface 20S in the planar direction. The third reference line L3 is a straight line that is parallel to the second reference line L2 and is set a predetermined distance D1 outward from the second reference line L2.

[0060] The intermediate portion 73 is sandwiched between the inner portion 71 and the outer portion 72 in the surface direction. The intermediate portion 73 is the portion of the electrolyte layer 7 between the first reference line L1 and the third reference line L3. The intermediate portion 73 is disposed outside the inner portion 71 and inside the outer portion 72. The intermediate portion 73 is connected to both the inner portion 71 and the outer portion 72. The boundary between the intermediate portion 73 and the inner portion 71 is defined by the first reference line L1. The boundary between the intermediate portion 73 and the outer portion 72 is defined by the third reference line L3. The center of the intermediate portion 73 in the surface direction is defined by the second reference line L2.

[0061] Here, the average thickness of the intermediate portion 73 is greater than the average thickness of the inner portion 71 .

[0062] The average thickness of the intermediate portion 73 is the average value of thicknesses T1, T2, and T3 at three locations that divide the intermediate portion 73 into four equal parts in the surface direction. The thicknesses T1, T2, and T3 of the intermediate portion 73 are thicknesses measured at three locations that divide the area between the first reference line L1 and the third reference line L3 into four equal parts in the surface direction. In this specification, thickness refers to the thickness in the Z-axis direction (thickness direction).

[0063] The average thickness of the inner portion 71 is the average value of thicknesses T4, T5, and T6 at three points that divide the portion of the inner portion 71 from the first reference line L1 to the predetermined distance D1 in the surface direction into four equal parts. The thicknesses T4, T5, and T6 of the inner portion 71 are thicknesses measured at three points that divide the portion between the first reference line L1 and the fourth reference line L4 into four equal parts in the surface direction. The fourth reference line L4 is a line that is symmetrical with the second reference line L2 with respect to the first reference line L1. The fourth reference line L4 is a straight line that is parallel to the first reference line L1 and is set twice the predetermined distance D1 inward from the second reference line L2. As described above, the predetermined distance D1 is half the thickness Ta of the metal support 20 on the first reference line L1.

[0064] The average thickness of the middle portion 73 is not particularly limited, but may be, for example, 10 μm or more and 100 μm or less. The average thickness of the inner portion 71 is not particularly limited, but may be, for example, 3 μm or more and 50 μm or less. The average thickness of the middle portion 73 is greater than the average thickness of the outer portion 72. The average thickness of the middle portion 73 is measured as described above.

[0065] The average thickness of the outer portion 72 is the average value of thicknesses T7, T8, and T9 at three locations that divide the outer portion 72 into four equal parts. The thicknesses T7, T8, and T9 of the outer portion 72 are thicknesses measured at three locations that divide the area from the third reference line L3 to the tip P7 of the electrolyte layer 7 into four equal parts in the planar direction. In this embodiment, the tip P7 of the electrolyte layer 7 is located outside the tip P20 of the first main surface 20S in the planar direction, but may be located on the tip P20 of the first main surface 20S or inside the tip P20 of the first main surface 20S.

[0066] The average thickness of the outer portion 72 is not particularly limited, but may be, for example, 3 μm or more and 50 μm or less. The average thickness of the outer portion 72 may be greater or smaller than the average thickness of the inner portion 71, or may be the same as the average thickness of the inner portion 71.

[0067] 3, the outer portion 72 may have a protruding portion 72a. The protruding portion 72a is a portion of the outer portion 72 that protrudes outward from the first main surface 20S of the metal support 20. In other words, the protruding portion 72a is a portion of the outer portion 72 that is located outward from the tip P20 of the first main surface 20S.

[0068] Although not shown, it is preferable that the protruding portion 72a of the outer portion 72 cover at least a part of the side surface 20U of the metal support 20. This allows the side surface 20U to be covered by the protruding portion 72a, thereby further suppressing heat radiation from the metal support 20.

[0069] (Features)

[0070] (1) As shown in Fig. 3, the electrolyte layer 7 has an inner portion 71, an outer portion 72, and an intermediate portion 73. The inner portion 71 covers the surface of the hydrogen electrode layer 6 and is spaced a predetermined distance D1 or more from the front end P6 of the hydrogen electrode layer 6 in the planar direction. The outer portion 72 covers substantially the entire region of the first main surface 20S that is exposed from the hydrogen electrode layer 6 and is spaced a predetermined distance D1 or more from the front end P6 of the hydrogen electrode layer 6 in the planar direction. The intermediate portion 73 is sandwiched between the inner portion 71 and the outer portion 72 in the planar direction. The average thickness of the intermediate portion 73 is greater than the average thickness of the inner portion 71.

[0071] In this manner, the outer portion 72 covers substantially the entire region of the first main surface 20S that is exposed from the hydrogen electrode layer 6, so that not only the rigidity of the metal support 20 but also the rigidity of the dense electrolyte layer 7 can be imparted to the outer periphery of the electrolysis cell 1. Therefore, the rigidity of the entire electrolysis cell 1 can be improved.

[0072] Furthermore, since the average thickness of the intermediate portion 73 is greater than the average thickness of the inner portion 71, it is possible to prevent cracks originating near the tip P6 of the hydrogen electrode layer 6 from occurring in the electrolyte layer 7. Specifically, this is as follows.

[0073] When the electrolysis cell 1 is started, the metal support 20 made of a metal material is more likely to rise in temperature than the cell body 10 made of ceramics. At this time, the temperature of the hydrogen electrode layer 6 in contact with the metal support 20 is more likely to rise, but the temperature of the part of the electrolyte layer 7 arranged on the hydrogen electrode layer 6 is less likely to rise. Therefore, thermal stress occurs between the part of the electrolyte layer 7 arranged on the hydrogen electrode layer 6 and the hydrogen electrode layer 6. Also, the temperature of the part of the electrolyte layer 7 in contact with the metal support 20 is more likely to rise, but the temperature of the part of the electrolyte layer 7 arranged on the hydrogen electrode layer 6 is less likely to rise. Therefore, thermal stress is likely to concentrate near the tip P6 of the hydrogen electrode layer 6, but as described above, the strength of the intermediate portion 73 is increased by making the average thickness of the intermediate portion 73 larger than the average thickness of the inner portion 71. Therefore, it is possible to suppress the occurrence of cracks in the intermediate portion 73 starting from the tip P6 of the hydrogen electrode layer 6. If cracks occur in the intermediate portion 73, part of the function of the electrolyte layer 7 will be lost, so it is important to suppress cracks in the intermediate portion 73.

[0074] (2) The average thickness of the intermediate portion 73 is greater than the average thickness of the outer portion 72. This makes it easier to make the intermediate portion 73 thicker, thereby sufficiently increasing the strength of the intermediate portion 73. This makes it possible to further prevent cracks from occurring in the intermediate portion 73, starting from the vicinity of the tip P6 of the hydrogen electrode layer 6.

[0075] (Modification of the embodiment) Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0076] [Variation 1] In the above embodiment, the thickness of the hydrogen electrode layer 6 is gradually thinner toward the tip P6 as shown in Fig. 3, but is not limited thereto. For example, the thickness of the hydrogen electrode layer 6 may be generally constant as a whole as shown in Fig. 4. Even in this case, the first to fourth reference lines L1 to L4 are set based on the tip P6 of the hydrogen electrode layer 6, thereby defining the inner portion 71, the outer portion 72, and the middle portion 73, and determining their average thicknesses.

[0077] 4, when the hydrogen electrode layer 6 has a side surface 6S formed along the Z-axis direction, it is preferable that the side surface 6S is unevenly formed, which can increase the interfacial strength between the hydrogen electrode layer 6 and the electrolyte layer 7 and reduce damage due to thermal stress when the temperature is increased or decreased.

[0078] [Variation 2] In the above embodiment, it has been described that the average thickness of the intermediate portion 73 is greater than the average thickness of the inner portion 71 in the cross section shown in Fig. 3. The configuration shown in Fig. 3 is preferably observed in all cross sections of the outer periphery of the electrolytic cell 1, but it is sufficient if it is observed in at least one cross section of the outer periphery of the electrolytic cell 1. This is because, if the configuration shown in Fig. 3 is observed in even one cross section, it is possible to suppress the occurrence of cracks in the intermediate portion 73 at least in that location.

[0079] [Variation 3] In the above embodiment, the hydrogen electrode layer 6 functions as a cathode and the oxygen electrode layer 9 functions as an anode, but the hydrogen electrode layer 6 may function as an anode and the oxygen electrode layer 9 may function as a cathode. In this case, the constituent materials of the hydrogen electrode layer 6 and the oxygen electrode layer 9 are switched, and a source gas is passed over the outer surface of the hydrogen electrode layer 6.

[0080] [Variation 4] In the above embodiment, the electrolysis cell 1 has been described as an example of an electrochemical cell, but the electrochemical cell is not limited to the electrolysis cell. An electrochemical cell is a general term for an element in which a pair of electrodes are arranged so that an electromotive force is generated from an overall oxidation-reduction reaction in order to convert electrical energy into chemical energy, and an element for converting chemical energy into electrical energy. Therefore, the electrochemical cell includes, for example, a fuel cell that uses oxide ions or protons as a carrier. [Explanation of symbols]

[0081] 1 cell 6 Hydrogen electrode layer 7 Electrolyte layer 71 Inner part 72 Outer part 73 Middle Section 8. Reaction prevention layer 9 Oxygen Polar Layer 10 Cell body 20 Metal support 20S 1st main surface 21 Supply hole 30 Flow path member 30a Flow path L1~L4 1st to 4th reference line P20 Tip of the first main surface P6 Hydrogen electrode tip D1 Predetermined distance

Claims

1. a metal support having a plurality of supply holes formed in a major surface thereof; a cell main body portion including a first electrode layer formed on the main surface and covering the plurality of supply holes, a second electrode layer, and an electrolyte layer disposed between the first electrode layer and the second electrode layer; Equipped with The electrolyte layer has, in a cross section perpendicular to the main surface, an inner portion covering a surface of the first electrode layer and spaced a predetermined distance or more from a tip of the first electrode layer in a planar direction parallel to the main surface; an outer portion spaced apart from a tip of the first electrode layer by the predetermined distance or more in the surface direction; an intermediate portion sandwiched between the inner portion and the outer portion in the surface direction; having the outer portion covers the entire main surface of the metal support from the intermediate portion to a tip of the main surface, the metal support is made of an alloy material containing Cr; The average thickness of the intermediate portion is greater than the average thickness of the inner portion and greater than the average thickness of the outer portion; The average thickness of the intermediate portion is an average value of thicknesses at three points that divide the intermediate portion into four equal parts in the surface direction, The average thickness of the inner portion is an average value of thicknesses at three locations that divide a portion of the inner portion from a first reference line to the predetermined distance in the surface direction into four equal parts, the first reference line is a straight line that is parallel to a second reference line that is a straight line that passes through the tip of the first electrode layer and is perpendicular to the main surface of the metal support, and is set inward from the second reference line by the predetermined distance; The average thickness of the outer portion is an average value of thicknesses at three points that divide the outer portion into four equal parts in the surface direction. Electrochemical cell.

2. The predetermined distance is half the thickness of the metal support.

10. The electrochemical cell of claim 1.

3. the first electrode layer has a side surface formed along a thickness direction perpendicular to the surface direction, The side surface is formed with projections and recesses.

3. An electrochemical cell according to claim 1 or 2.

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