Electrochemical cell

Abstract

An electrolysis cell (1) is provided with a gas container (3) and a cell body part (2). An internal space (3a) of the gas container (3) has a gas supply chamber (a1) connected to a gas supply hole (15), a gas discharge chamber (a2) connected to a gas discharge hole (16), and a gas circulation chamber (a3) connected to communication holes (11) and disposed between the gas supply chamber (a1) and the gas discharge chamber (16). In a plan view of a first main surface (12) of a metal support (10), a welded part (30) includes a first constricted part (31) for partitioning between the gas circulation chamber (a3) and the gas supply chamber (a1).

Description

electrochemical cell

[0001] The present invention relates to electrochemical cells.

[0002] Patent Document 1 discloses an electrochemical cell (electrolysis cell, fuel cell, etc.) having a cell main body disposed on a gas container. The gas container has a metal support having a plurality of communication holes formed on a main surface thereof and a flow path member forming an internal space between the metal support and the flow path member. The metal support is welded to the flow path member.

[0003] Japanese Patent Application Laid-Open No. 2020-533737

[0004] In order to smooth the flow of current inside the gas container, it is effective to increase the area of ​​the main surface of the metal support and thereby increase the weld length. However, when the area of ​​the main surface of the metal support is increased, the distance between the cell body and the weld increases, resulting in current loss between them.

[0005] An object of the present invention is to provide an electrochemical cell that can suppress current loss in a gas container.

[0006] An electrochemical cell according to a first aspect of the present invention includes a gas container and a cell main body. The gas container includes a metal support having a plurality of communication holes, gas supply holes, and gas exhaust holes formed on a main surface thereof, a flow path member forming an internal space between the metal support and the cell main body, and a weld that seals a gap between the metal support and the flow path member. The cell main body is disposed on the main surface and covers the plurality of communication holes. The internal space includes a gas supply chamber connected to the gas supply holes, a gas exhaust chamber connected to the gas exhaust holes, and a gas flow chamber connected to the plurality of communication holes and disposed between the gas supply chamber and the gas exhaust chamber. In a plan view of the main surface, the weld has a constriction that separates the gas flow chamber from the gas supply chamber or the gas exhaust chamber.

[0007] An electrochemical cell according to a second aspect of the present invention is related to the first aspect, wherein the gas container has a recess formed along the constricted portion in a plan view of the main surface.

[0008] An electrochemical cell according to a third aspect of the present invention is the electrochemical cell according to the first or second aspect, wherein, in a plan view of the main surface, corners of the constricted portion are rounded.

[0009] An electrochemical cell according to a fourth aspect of the present invention is related to any one of the first to third aspects, and when the constricted portion separates the gas flow chamber and the gas supply chamber in a plan view of the main surface, a corner of a first part of the weld facing the gas supply chamber is rounded.

[0010] An electrochemical cell according to a fifth aspect of the present invention relates to any one of the first to fourth aspects, and when the constricted portion separates the gas flow chamber and the gas exhaust chamber in a plan view of the main surface, a corner of a second part of the weld facing the gas exhaust chamber is rounded.

[0011] An electrochemical cell according to a sixth aspect of the present invention is the electrochemical cell according to any one of the first to fifth aspects, wherein, in a plan view of the main surface, a corner of a third portion of the welded portion facing the gas flow chamber is rounded.

[0012] According to the present invention, it is possible to provide an electrochemical cell that can suppress current loss in a gas container.

[0013] Fig. 1 is a plan view of an electrolytic cell according to an embodiment. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1. Fig. 3 is a plan view of an electrolytic cell according to Modification 1. Fig. 4 is a plan view of an electrolytic cell according to Modification 2. Figs. 5(a) to (h) are plan views of electrolytic cells according to Modification 2.

[0014] (Electrolytic cell 1) Fig. 1 is a plan view of an electrolytic cell 1 according to an embodiment. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1.

[0015] The electrolytic cell 1 is an example of an "electrochemical cell" according to the present invention. The electrolytic cell 1 is a so-called metal-supported type.

[0016] The electrolytic cell 1 is formed in a plate shape extending in the X-axis and Y-axis directions. In the present embodiment, the electrolytic cell 1 is formed in a rectangular shape extending in the Y-axis direction when viewed in a plan view from the Z-axis direction perpendicular to the X-axis and Y-axis directions. However, the planar shape of the electrolytic cell 1 is not particularly limited, and may be a polygon other than a rectangle, an ellipse, a circle, or the like.

[0017] As shown in FIGS. 1 and 2, the electrolysis cell 1 includes a cell body 2 and a gas container 3 .

[0018] (Cell Main Body 2) The cell main body 2 is supported by the gas container 3. The cell main body 2 is disposed on a first main surface 12 of a metal support 10 of the gas container 3, which will be described later.

[0019] 2, the cell body 2 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 stacked in this order in the Z-axis direction from the gas container 3 side. The hydrogen electrode layer 6, electrolyte layer 7, and oxygen electrode layer 9 are essential components, while the reaction prevention layer 8 is optional.

[0020] [Hydrogen Electrode Layer 6 ] The hydrogen electrode layer 6 is formed on the first main surface 12 of the metal support 10 .

[0021] The hydrogen electrode layer 6 is supplied with a source gas through each of the communication holes 11 of the metal support 10. The source gas contains at least water vapor (H ２ O).

[0022] The raw material gas is H ２ When only O is contained, the hydrogen electrode layer 6 converts H from the raw material gas according to the electrochemical reaction of water electrolysis shown in the following formula (1): ２ Generate.

[0023] Hydrogen electrode layer 6: H ２ O + 2e － →H ２ +O ２－ ...(1)

[0024] The raw material gas is H ２ O plus CO ２ In this case, the hydrogen electrode layer 6 converts the source gas into H according to the electrochemical reactions of co-electrolysis shown in the following formulas (2), (3), and (4).２ , CO and O ２－ Generate.

[0025] Hydrogen electrode layer 6: CO ２ +H ２ O+4e － →CO+H ２ +20 ２－ ... (2) H ２ Electrochemical reaction of O: H ２ O + 2e － →H ２ +O ２－ ... (3) CO ２ Electrochemical reaction of: CO ２ +2e － →CO+O ２－ ...(4)

[0026] H generated in the hydrogen electrode layer 6 ２ flows out from each of the communication holes 11 of the metal support 10 into the internal space 3a described below.

[0027] The hydrogen electrode layer 6 is a porous body having electron conductivity. The hydrogen electrode layer 6 contains nickel (Ni). In the case of co-electrolysis, Ni functions as an electron conductor and also functions as a conductor for the generated H ２ and CO contained in the raw material gas ２ It also functions as a thermal catalyst that promotes the thermal reaction with HCl and maintains an appropriate gas composition for methanation, Fischer-Tropsch (FT) synthesis, etc. The Ni contained in the hydrogen electrode layer 6 is basically present in the form of metallic Ni during operation of the electrolysis cell 1, but a portion of it may also be present in the form of nickel oxide (NiO).

[0028] The hydrogen electrode layer 6 may contain an ion-conductive material, such as yttria-stabilized zirconia (YSZ), calcia-stabilized zirconia (CSZ), scandia-stabilized zirconia (ScSZ), gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), (La,Sr)(Cr,Mn)O, or the like. ３ , (La,Sr)TiO ３ , Sr ２ (Fe, Mo) ２ O ６ , (La, Sr)VO ３, (La,Sr)FeO ３ and mixed materials of two or more of these.

[0029] 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.

[0030] 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 spraying 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.

[0031] [Electrolyte Layer 7] The electrolyte layer 7 is formed on the hydrogen electrode layer 6. The electrolyte layer 7 is disposed between the hydrogen electrode layer 6 and the oxygen electrode layer 9. In this embodiment, the electrolyte layer 7 is sandwiched between the hydrogen electrode layer 6 and the reaction prevention layer 8 and is connected to both of them.

[0032] The electrolyte layer 7 covers the hydrogen electrode layer 6 and is connected to the first main surface 12 of the metal support 10 .

[0033] The electrolyte layer 7 is a dense body having oxide ion conductivity. ２－ to the oxygen electrode layer 9. The electrolyte layer 7 is made of an oxide ion conductive material. The electrolyte layer 7 can be made of, for example, YSZ, GDC, ScSZ, SDC, or LSGM (lanthanum gallate), with YSZ being particularly suitable.

[0034] 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.

[0035] The method for forming the electrolyte layer 7 is not particularly limited, and may be a baking method, a spray coating method, a PVD method, a CVD method, or the like.

[0036] [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 from 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.

[0037] The reaction prevention layer 8 is made of an oxide ion conductive material, such as GDC or SDC.

[0038] 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.

[0039] The method for forming the reaction prevention layer 8 is not particularly limited, and may be a baking method, a spray coating method, a PVD method, a CVD method, or the like.

[0040] [Oxygen Electrode Layer 9] The oxygen electrode layer 9 is disposed on the opposite side of the electrolyte layer 7 from the hydrogen electrode layer 6. 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.

[0041] The oxygen electrode layer 9 reacts with O transferred from the hydrogen electrode layer 6 through the electrolyte layer 7 in accordance with the chemical reaction of the following formula (5): ２－ From O ２ Generate.

[0042] Oxygen electrode layer 9: 2O ２－ →O ２ +4e － ...(5)

[0043] The oxygen electrode layer 9 is a porous body having oxide ion conductivity and electron conductivity. The oxygen electrode layer 9 is made of, for example, (La, Sr)(Co, Fe)O ３ , (La,Sr)FeO ３ , La(Ni,Fe)O ３ , (La,Sr)CoO ３ , and (Sm,Sr)CoO ３and an oxide ion conductive material (such as GDC).

[0044] 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.

[0045] The method for forming the oxygen electrode layer 9 is not particularly limited, and may be a firing method, a spray coating method, a PVD method, a CVD method, or the like.

[0046] (Gas container 3) The gas container 3 supports the cell main body 2. The gas container 3 is used for supplying and discharging gas. The gas container 3 supplies the source gas to the cell main body 2 (specifically, the hydrogen electrode layer 6). The gas container 3 discharges to the outside the product gas generated in the hydrogen electrode layer 6 and the remaining source gas not consumed in the cell main body 2 (specifically, the hydrogen electrode layer 6).

[0047] The gas container 3 has a metal support 10, a flow path member 20, and a welded portion 30. The gas container 3 has an internal space 3a therein.

[0048] [Metal Support 10] The metal support 10 supports the cell main body 2. In this embodiment, the metal support 10 is formed in a plate shape. The metal support 10 may be in a flat plate shape or a curved plate shape.

[0049] The metal support 10 is only required to be able to support the cell body 2, and its thickness is not particularly limited, but can be, for example, 0.1 mm or more and 2.0 mm or less.

[0050] The metal support 10 has a plurality of communication holes 11 , a first main surface 12 and a second main surface 13 .

[0051] Each communication hole 11 is formed in the first main surface 12. Each communication hole 11 penetrates the metal support 10 from the first main surface 12 to the second main surface 13. Each communication hole 11 opens to the first main surface 12 and the second main surface 13. The opening of each communication hole 11 on the first main surface 12 side is covered by the cell main body 2 (specifically, the hydrogen electrode layer 6). The opening of each communication hole 11 on the second main surface 13 side is connected to a gas flow chamber a3 (described later) in the internal space 3a.

[0052] Each of the communication holes 11 can be formed by mechanical processing (for example, punching), laser processing, or chemical processing (for example, etching).

[0053] In this embodiment, each communication hole 11 is formed linearly along the Z-axis direction. However, each communication hole 11 may be inclined with respect to the Z-axis direction or may not be linear. Furthermore, the communication holes 11 may be connected to each other.

[0054] The first main surface 12 is provided on the opposite side to the second main surface 13. The cell main body 2 is disposed on the first main surface 12. The flow path member 20 is bonded to the second main surface 13.

[0055] The metal support 10 has gas supply holes 15 and gas exhaust holes 16 .

[0056] The gas supply holes 15 are formed in the first main surface 12. The gas supply holes 15 penetrate the metal support 10 from the first main surface 12 to the second main surface 13. The gas supply holes 15 open to both the first main surface 12 and the second main surface 13. The opening of the gas supply hole 15 on the first main surface 12 side is connected to a gas supply hole 25 of a flow path member 20 of another electrolysis cell 1 (not shown). The opening of the gas supply hole 15 on the second main surface 13 side is connected to a gas supply chamber a1 (described later) in the internal space 3a.

[0057] The gas exhaust hole 16 is formed in the first main surface 12. The gas exhaust hole 16 penetrates the metal support 10 from the first main surface 12 to the second main surface 13. The gas exhaust hole 16 opens to both the first main surface 12 and the second main surface 13. The opening of the gas exhaust hole 16 on the first main surface 12 side is connected to a gas exhaust hole 26 of a flow path member 20 of another electrolysis cell 1 (not shown). The opening of the gas exhaust hole 16 on the second main surface 13 side is connected to a gas exhaust chamber a2 (described later) in the internal space 3a.

[0058] The metal support 10 is made of a metal material. For example, the metal support 10 can be 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 10 is not particularly limited, but can be set to 4 mass % or more and 30 mass % or less.

[0059] The metal support 10 may contain Ti (titanium) or Zr (zirconium). The Ti content in the metal support 10 is not particularly limited, but may be 0.01 mol % or more and 1.0 mol % or less. The Zr content in the metal support 10 is not particularly limited, but may be 0.01 mol % or more and 0.4 mol % or less. The metal support 10 may contain Ti in the form of TiO ２ (titania), or Zr may be contained as ZrO ２ It may be contained as (zirconia).

[0060] [Flow Channel Member 20] The flow channel member 20 is joined to the metal support 10. The flow channel member 20 is joined to the metal support 10 by a weld 30. That is, the flow channel member 20 is welded to the metal support 10.

[0061] The flow path member 20 is made of a metal material. For example, the flow path member 20 can be made of the above-mentioned alloy material. The material composition of the flow path member 20 may be the same as or different from the material composition of the metal support 10.

[0062] The flow path member 20 has a frame portion 21 and an interconnector 22. In this embodiment, the frame portion 21 and the interconnector 22 are separate members. The frame portion 21 is joined to the interconnector 22 by a welded portion 30. That is, the frame portion 21 is welded to the interconnector 22.

[0063] The frame portion 21 is formed in an annular shape. The frame portion 21 is disposed on the outer edge of the interconnector 22. The frame portion 21 functions as a spacer for forming a gap between the metal support 10 and the interconnector 22. The thickness of the frame portion 21 is not particularly limited, but can be, for example, 0.1 mm or more and 2.0 mm or less.

[0064] The interconnector 22 is disposed on the opposite side of the metal support 10 with respect to the frame 21. The interconnector 22 is an electrical connection member for electrically connecting the electrolytic cell 1 to another electrolytic cell or an external power source. The interconnector 22 is formed in a plate shape. The interconnector 22 may be in the shape of a flat plate or a curved plate. The thickness of the interconnector 22 is not particularly limited, but may be, for example, 0.1 mm or more and 2.0 mm or less.

[0065] The interconnector 22 has a first main surface 23 and a second main surface 24. The first main surface 23 faces the second main surface 13 of the metal support 10. The second main surface 24 is provided on the opposite side of the first main surface 23.

[0066] The interconnector 22 has a gas supply hole 25 and a gas exhaust hole 26 .

[0067] The gas supply holes 25 are formed in the first main surface 23. The gas supply holes 25 penetrate the interconnector 22 from the first main surface 23 to the second main surface 24. The openings of the gas supply holes 25 on the first main surface 23 side communicate with a gas supply chamber a1 (described later) in the internal space 3a. The openings of the gas supply holes 25 on the second main surface 24 side communicate with gas supply holes 15 of a metal support 10 of another electrolysis cell 1 (not shown).

[0068] The gas exhaust hole 26 is formed in the first main surface 23. The gas exhaust hole 26 penetrates the interconnector 22 from the first main surface 23 to the second main surface 24. The gas exhaust hole 26 opens to both the first main surface 23 and the second main surface 24. The opening of the gas exhaust hole 26 on the first main surface 23 side communicates with a gas exhaust chamber a2 (described later) in the internal space 3a. The opening of the gas exhaust hole 26 on the second main surface 24 side communicates with a gas exhaust hole 16 of a metal support 10 of another electrolysis cell 1 (not shown).

[0069] [Internal Space 3a] The internal space 3a is a space between the metal support 10 and the flow path member 20. The outer periphery of the internal space 3a in the surface direction is sealed by a welded portion 30.

[0070] As shown in FIGS. 1 and 2, the internal space 3a has a gas supply chamber a1, a gas discharge chamber a2, and a gas flow chamber a3.

[0071] The gas supply chamber a1 communicates with the gas supply holes 15 of the metal support 10. The gas supply chamber a1 communicates with the gas supply holes 25 of the flow path member 20. The gas supply chamber a1 communicates with the gas flow chamber a3 in the gas flow direction.

[0072] In this specification, the gas flow direction means a direction parallel to a straight line L1 connecting the geometric center of the gas supply hole 15 and the geometric center of the gas exhaust hole 16 in a plan view of the first main surface 12 of the metal support 10. In the following description, a direction perpendicular to the gas flow direction in a plan view of the first main surface 12 of the metal support 10 is referred to as a width direction.

[0073] The gas discharge chamber a2 is connected to the gas discharge hole 16 of the metal support 10. The gas discharge chamber a2 is connected to the gas discharge hole 26 of the flow path member 20. The gas discharge chamber a2 is connected to the gas flow chamber a3 in the gas flow direction. The gas discharge chamber a2 is disposed on the opposite side of the gas supply chamber a1 in the gas flow direction with the gas flow chamber a3 as the reference.

[0074] The gas flow chamber a3 is connected to each of the communication holes 11 of the metal support 10. The gas flow chamber a3 is disposed between the gas supply chamber a1 and the gas discharge chamber a2 in the gas flow direction.

[0075] The source gas is supplied to the gas supply chamber a1 through the gas supply hole 15 of the metal support 10 or the gas supply hole 25 of the flow path member 20. The source gas that has flowed into the gas supply chamber a1 flows from the gas supply chamber a1 into the gas flow chamber a3. The source gas that has flowed into the gas flow chamber a3 flows from the gas flow chamber a3 into each of the communication holes 11 of the metal support 10. The product gas generated in the hydrogen electrode layer 6 flows into the gas flow chamber a3 through each of the communication holes 11 of the metal support 10. The product gas generated in the hydrogen electrode layer 6 and the remaining source gas not consumed in the hydrogen electrode layer 6 flow from the gas flow chamber a3 into the gas discharge chamber a2. The product gas and remaining source gas that have flowed into the gas discharge chamber a2 are discharged to the outside through the gas discharge hole 16 of the metal support 10 or the gas discharge hole 26 of the flow path member 20.

[0076] 1, the welded portion 30 has a first constricted portion 31 and a second constricted portion 32. Each of the first constricted portion 31 and the second constricted portion 32 is an example of a "constricted portion" according to the present invention.

[0077] The first constricted portion 31 is formed between the gas supply holes 15 of the metal support 10 and the cell main body 2 in a plan view of the first main surface 12 of the metal support 10. The first constricted portion 31 is a recess formed in a convex shape toward the inside of the internal space 3a in the width direction. In other words, the first constricted portion 31 is a portion of the welded portion 30 that is narrow in the width direction. The first constricted portion 31 is narrower than the portion of the welded portion 30 upstream of the first constricted portion 31, and is also narrower than the portion of the welded portion 30 downstream of the first constricted portion 31. Therefore, the width of the welded portion 30 in the width direction is partially narrowed at the first constricted portion 31.

[0078] 1 , the first constricted portion 31 separates the gas supply chamber a1 from the gas flow chamber a3. The space in the internal space 3a upstream of the first constricted portion 31 is the gas supply chamber a1, and the space in the internal space 3a downstream of the first constricted portion 31 is the gas flow chamber a3. Specifically, the upstream side of a straight line L2 that passes through the innermost points P1 and P2 of the first constricted portion 31 and is parallel to the width direction is the gas supply chamber a1, and the downstream side of the straight line L2 is the gas flow chamber a3.

[0079] The welded portion 30 has the first constricted portion 31, which allows the gas supply chamber a1 to be separated from the gas flow chamber a3 by the first constricted portion 31. This allows the area of ​​the first main surface 12 of the metal support 10 to be increased and the length of the welded portion 30 to be longer than in the case where the gas supply chamber a1 is not present. This allows the current to flow smoothly within the gas container 3.

[0080] Furthermore, since the welded portion 30 has the first constricted portion 31, a part of the welded portion 30 can be extended in the width direction along the cell main body 2. Therefore, the distance between the cell main body 2 and the first constricted portion 31 of the welded portion 30 can be shortened, and current loss between the cell main body 2 and the welded portion 30 can be suppressed.

[0081] As described above, by providing the first constricted portion 31 to the welded portion 30, it is possible to suppress current loss in the gas container 3 while smoothing the flow of current within the gas container 3.

[0082] The second constricted portion 32 is formed between the gas exhaust hole 16 of the metal support 10 and the cell main body 2 in a plan view of the first main surface 12 of the metal support 10. The second constricted portion 32 is a recess formed in a convex shape toward the inside in the width direction of the internal space 3a. In other words, the second constricted portion 32 is a portion of the welded portion 30 that is narrow in the width direction. The second constricted portion 32 is narrower than the portion of the welded portion 30 upstream of the second constricted portion 32, and is also narrower than the portion of the welded portion 30 downstream of the second constricted portion 32. Therefore, the width of the welded portion 30 in the width direction is partially narrowed at the second constricted portion 32.

[0083] 1 , the second constricted portion 32 separates the gas discharge chamber a2 from the gas flow chamber a3. The space in the internal space 3a upstream of the second constricted portion 32 is the gas flow chamber a3, and the space in the internal space 3a downstream of the second constricted portion 32 is the gas discharge chamber a2. Specifically, the upstream side of a straight line L3 that passes through the innermost points P3 and P4 of the second constricted portion 32 and is parallel to the width direction is the gas flow chamber a3, and the downstream side of the straight line L3 is the gas discharge chamber a2.

[0084] The welded portion 30 has the second constricted portion 32, which provides a gas exhaust chamber a2 separated from the gas flow chamber a3 by the second constricted portion 32. This increases the area of ​​the first main surface 12 of the metal support 10 and increases the length of the welded portion 30 compared to when the gas exhaust chamber a2 does not exist. This allows the current to flow smoothly within the gas container 3.

[0085] Furthermore, since the welded portion 30 has the second constricted portion 32, a portion of the welded portion 30 can be extended in the width direction along the cell main body 2. Therefore, the distance between the cell main body 2 and the second constricted portion 32 of the welded portion 30 can be shortened, and current loss between the cell main body 2 and the welded portion 30 can be suppressed.

[0086] As described above, by providing the welded portion 30 with the second constricted portion 32, it is possible to suppress current loss in the gas container 3 while smoothing the flow of current within the gas container 3.

[0087] As shown in FIG. 1, the welded portion 30 has a first portion 33, a second portion 34, and a third portion 35.

[0088] The first portion 33 is a portion of the welded portion 30 that faces the gas supply chamber a1. The first portion 33 includes a part of the first constricted portion 31. Specifically, the first portion 33 includes a portion of the first constricted portion 31 that is upstream of the innermost points P1 and P2.

[0089] 1, the corner of the first portion 33 preferably has a rounded shape in plan view. This allows the corner of the gas supply chamber a1 to be streamlined, thereby preventing gas from accumulating at the corner of the gas supply chamber a1 and allowing smooth gas flow within the gas supply chamber a1. In this specification, a corner means a region where two straight lines connect in plan view.

[0090] The second portion 34 is a portion of the welded portion 30 that faces the gas discharge chamber a2. The second portion 34 includes a part of the second constricted portion 32. Specifically, the second portion 34 includes a portion of the second constricted portion 32 that is downstream of the innermost points P3 and P4.

[0091] 1, the corner of the second portion 34 preferably has an R-shape in plan view, which allows the corner of the gas discharge chamber a2 to be streamlined, thereby preventing gas from accumulating at the corner of the gas discharge chamber a2 and allowing the gas to flow smoothly within the gas discharge chamber a2.

[0092] The third portion 35 is a portion of the welded portion 30 that faces the gas flow chamber a3. The third portion 35 includes a portion of the first constricted portion 31 and a portion of the second constricted portion 32. Specifically, the third portion 35 includes a portion of the first constricted portion 31 that is downstream of the innermost point P1 and a portion of the second constricted portion 32 that is upstream of the innermost point P3, and a portion of the first constricted portion 31 that is downstream of the innermost point P2 and a portion of the second constricted portion 32 that is upstream of the innermost point P4.

[0093] 1, it is preferable that the corner of the third portion 35 has an R-shape in plan view, which allows the corner of the gas flow chamber a3 to be streamlined, thereby preventing gas from accumulating at the corner of the gas flow chamber a3 and allowing the gas to flow smoothly within the gas flow chamber a3.

[0094] 1, the corner of the first constricted portion 31 preferably has an R-shape in plan view, which allows the corner of the first constricted portion 31 to be streamlined, thereby smoothing the gas flow from the gas supply chamber a1 to the gas flow chamber a3 and preventing the first constricted portion 31 from interfering with the flow of current from the cell main body 2 to the first part 33 of the welded portion 30.

[0095] 1, the corner of the second constricted portion 32 preferably has an R-shape in plan view, which allows the corner of the second constricted portion 32 to be streamlined, thereby smoothing the gas flow from the gas flow chamber a3 to the gas discharge chamber a2 and preventing the second constricted portion 32 from interfering with the flow of current from the cell main body 2 to the second part 34 of the welded portion 30.

[0096] 1, the gas container 3 preferably has a first recess 3b formed along the first constricted portion 31 in a plan view of the first main surface 12 of the metal support 10. This allows the gas container 3 to have flexibility, thereby improving the durability of the gas container 3. From this viewpoint, it is more preferable that the corners of the first recess 3b have an R-shape in a plan view.

[0097] The first recess 3b is formed between the gas supply hole 15 of the metal support 10 and the cell main body 2 in a plan view of the first main surface 12 of the metal support 10. The first recess 3b is formed in a convex shape facing inward in the width direction of the internal space 3a. The width of the gas container 3 in the width direction is partially narrowed at the first recess 3b.

[0098] 1, the gas container 3 preferably has a second recess 3c formed along the second constricted portion 32 in a plan view of the first main surface 12 of the metal support 10. This allows the gas container 3 to have flexibility, thereby improving the durability of the gas container 3. From this viewpoint, it is more preferable that the corner of the second recess 3c has an R-shape in a plan view.

[0099] The second recess 3c is formed between the gas exhaust hole 16 of the metal support 10 and the cell main body 2 in a plan view of the first main surface 12 of the metal support 10. The second recess 3c is formed in a convex shape facing inward in the width direction of the internal space 3a. The width of the gas container 3 in the width direction is partially narrowed at the second recess 3c.

[0100] (Modifications of the Embodiment) Although the embodiment of the present invention has 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.

[0101] [Modification 1] In the above embodiment, the corners of the first constricted portion 31, the second constricted portion 32, the first portion 33, the second portion 34, and the third portion 35 of the welded portion 30 are rounded, but this is not limited to this. As shown in Fig. 3 , at least one corner of the first constricted portion 31, the second constricted portion 32, the first portion 33, the second portion 34, and the third portion 35 of the welded portion 30 may be bent.

[0102] [Modification 2] In the above embodiment, the gas container 3 has the first recess 3 b and the second recess 3 c, but this is not limited to this. As shown in Fig. 4, the gas container 3 does not have at least one of the first recess 3 b and the second recess 3 c.

[0103] [Modification 3] In the above embodiment, the welded portion 30 has a shape that is symmetrical in the width direction, but this is not limitative.

[0104] For example, the first constricted portion 31 does not need to be recessed on both sides in the width direction, but may be recessed on only one side in the width direction. Similarly, the second constricted portion 32 does not need to be recessed on both sides in the width direction, but may be recessed on only one side in the width direction.

[0105] [Variation 4] In the above embodiment, the electrolysis cell 1 is formed into a rectangle extending in the Y-axis direction. However, as shown in FIGS. 5( a) to 5( h), the shape of the electrolysis cell 1 can be modified as appropriate. Specifically, as shown in FIGS. 5( a) to 5( e), the depths of the first recess 3b and the second recess 3c of the gas container 3 can be modified as appropriate. Furthermore, as shown in FIG. 5( f), in the gas container 3, the first recess 3b and the second recess 3c may be asymmetric in the width direction, the gas supply hole 15 and the gas exhaust hole 16 may be offset from the center in the width direction, and the widths of the gas supply chamber a1 and the gas exhaust chamber a2 may be narrower than the width of the gas flow chamber a3. Furthermore, as shown in FIG. 5( g), the cell main body 2 may be a rectangle extending in the X-axis direction. Furthermore, in the gas container 3, the widths of the gas supply chamber a1 and the gas exhaust chamber a2 may be wider than the width of the gas flow chamber a3, as shown in FIG. 5( h).

[0106] [Modification 5] In the above embodiment, the frame 21 and the interconnector 22 that constitute the flow path member 20 are separate members, but the frame 21 and the interconnector 22 may be integrated.

[0107] [Variation 6] In the above embodiment, an electrolytic cell has been described as an example of an electrochemical cell, but the electrochemical cell is not limited to an electrolytic 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, electrochemical cells include, for example, fuel cells that use oxide ions or protons as carriers.

[0108] REFERENCE SIGNS LIST 1...electrolytic cell, 2...cell main body, 6...hydrogen electrode layer, 7...electrolyte layer, 8...reaction prevention layer, 9...oxygen electrode layer, 3...gas container, 3a...internal space, a1...gas supply chamber, a2...gas exhaust chamber, a3...gas flow chamber, 3b...first recess, 3c...second recess, 10...metal support, 11...communication hole, 12...first main surface, 13...second main surface, 15...gas supply hole, 16...gas exhaust hole, 20...flow path member, 21...frame, 22...interconnector, 30...welded portion, 31...first constricted portion, 32...second constricted portion, 33...first portion, 34...second portion, 35...third portion

Claims

1. An electrochemical cell comprising: a gas container having a metal support having a plurality of communication holes, gas supply holes, and gas exhaust holes formed in a main surface thereof; a flow path member which forms an internal space between the metal support and the gas container; and a cell main body which is disposed on the main surface and covers the plurality of communication holes; wherein the internal space has a gas supply chamber which is connected to the gas supply holes, a gas exhaust chamber which is connected to the gas exhaust hole, and a gas circulation chamber which is connected to the plurality of communication holes and is disposed between the gas supply chamber and the gas exhaust chamber; and wherein, in a plan view of the main surface, the weld has a constriction which separates the gas circulation chamber from the gas supply chamber or the gas exhaust chamber.

2. The electrochemical cell according to claim 1, wherein the gas container has a recess formed along the constricted portion in a plan view of the main surface.

3. The electrochemical cell according to claim 1 or 2, wherein corners of the constricted portion are rounded in plan view of the main surface.

4. The electrochemical cell according to claim 1, wherein, when the constricted portion separates the gas flow chamber and the gas supply chamber in a plan view of the main surface, a corner of a first portion of the welded portion facing the gas supply chamber is rounded.

5. The electrochemical cell according to claim 1, wherein, when the constricted portion separates the gas flow chamber and the gas exhaust chamber in a plan view of the main surface, a corner of a second portion of the welded portion facing the gas exhaust chamber is rounded.

6. The electrochemical cell according to claim 1, wherein, in a plan view of the main surface, a corner of a third portion of the welded portion facing the gas flow chamber is rounded.

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