Electrochemical cell, solid oxide fuel cell, solid oxide electrolysis cell, and method for manufacturing electrochemical cell

Abstract

The present invention comprises: a cell main body part in which a first electrode layer, an electrolyte layer, and a second electrode layer are stacked in this order; and a metal support body which supports the cell main body part. The metal support body comprises: a support part which comprises a support surface that supports one main surface of the cell main body part, and an opposite surface on the reverse side of the support surface, and which can communicate a gas between the support surface and the opposite surface; and a frame part which is disposed so as to surround the outer periphery of the support part. The thickness of the support part is formed to be thinner than the thickness of the frame part.

Description

Electrochemical cell, solid oxide fuel cell, solid oxide electrolysis cell, and method for manufacturing electrochemical cell

[0001] The present invention relates to an electrochemical cell, a solid oxide fuel cell, a solid oxide electrolysis cell, and a method for manufacturing an electrochemical cell.

[0002] JP6757433B discloses an electrochemical cell including a cell body having a first electrode layer, an electrolyte layer, and a second electrode layer, a support surface that supports the cell body, and a metal support that has through holes that open into the support surface and supports the cell body.

[0003] The through holes in the metal support disclosed in JP 6757433B and other publications are formed, for example, using a fiber laser (a laser using a laser diode or the like as a light source). In this case, the laser energy is concentrated at the position where the laser is irradiated on the surface of the metal support, resulting in a large opening. If an electrode layer is formed in this state, the material of the electrode layer sinks into the opening, which causes the uneven shape caused by the sinking of the electrode layer to be transferred to the upper surface of the electrode layer and the electrolyte layer formed on the upper surface. If the electrode layer and electrolyte layer are sintered with such an uneven shape in the electrolyte layer, cracks may occur in the electrolyte layer, potentially resulting in gas leaks.

[0004] Therefore, an object of the present invention is to provide an electrochemical cell, a solid oxide fuel cell, a solid oxide electrolysis cell, and a method for manufacturing an electrochemical cell that reduce the occurrence of cracks in the electrolyte layer.

[0005] According to one aspect of the present invention, a cell includes a cell main body portion formed by stacking a first electrode layer, an electrolyte layer, and a second electrode layer in that order, and a metal support supporting the cell main body portion, wherein the metal support includes a support surface supporting one main surface of the cell main body portion and an opposite surface of the support surface, and the support portion is capable of communicating gas between the support surface and the opposite surface, and a frame portion arranged to surround the outer periphery of the support portion, and the thickness of the support portion is formed to be thinner than the thickness of the frame portion.

[0006] FIG. 1 is a cross-sectional view of an electrochemical cell of a first embodiment. FIG. 2 is a bottom view of the electrochemical cell of the first embodiment. FIG. 3 is a partial detailed view showing a support portion and an anode support layer of the electrochemical cell of the first embodiment. FIG. 4 is a flow diagram showing a manufacturing process of the electrochemical cell of the first embodiment. FIG. 5 is a cross-sectional view of an electrochemical cell of a first comparative example. FIG. 6 is a cross-sectional view of an electrochemical cell of a second comparative example. FIG. 7 is a cross-sectional view of an electrochemical cell of the second embodiment. FIG. 8 is a bottom view of an electrochemical cell of the second embodiment. FIG. 9 is a cross-sectional view of an electrochemical cell of a third embodiment. FIG. 10 is a cross-sectional view of an electrochemical cell of a fourth embodiment. FIG. 11 is a schematic view of an electrochemical cell of this embodiment used as a solid oxide electrolysis cell.

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] [First embodiment] Fig. 1 is a cross-sectional view of an electrochemical cell of the first embodiment. Fig. 2 is a bottom view of the electrochemical cell of the first embodiment. The electrochemical cell of the first embodiment is formed by a metal support 1 and a cell main body 6 (anode support layer 2 (first electrode layer), anode active layer 3 (first electrode layer), electrolyte layer 4, and air cathode layer 5 (second electrode layer)).

[0009] The cell body 6 (electrolyte layer 4) is a ２－ In the first embodiment, the cell body 6 functions as a solid oxide fuel cell that generates electricity by supplying an anode gas (hydrogen gas) to the first electrode layer (anode support layer 2, anode active layer 3) and a cathode gas (air, oxygen) to the second electrode layer (air cathode layer 5).

[0010] The metal support 1 has a plate shape with a predetermined thickness. As shown in FIG. 2 , the metal support 1 has, for example, a rectangular shape in plan view, but may have other shapes. A recess 11 is formed in the metal support 1, and the portion that is outside the recess 11 in plan view becomes a frame portion 13, and the portion that is the bottom surface of the recess 11 becomes a support portion 12 (support surface 121). As shown in FIG. 2 , the recess 11 has, for example, a rectangular shape in plan view, but may have other shapes.

[0011] A plurality of through holes 123 are formed in the bottom surface of the recess 11 of the metal support 1, that is, in the support portion 12.

[0012] The through holes 123 have a cross-sectional shape that is, for example, circular, and communicate with the support surface 121 and the opposite surface thereof, the gas flow surface 122. The arrangement pattern of the through holes 123 can be set arbitrarily, but it is preferable to arrange them so that they are distributed approximately uniformly in the support part 12 in a plan view.

[0013] The through-holes 123 can be formed by mechanical processing (for example, punching), laser processing, or chemical processing (for example, etching), but in this embodiment, they are preferably formed by a fiber laser.

[0014] The through holes 123 allow gas to pass between the support surface 121 and the flow surface 122. However, instead of forming the through holes 123, the metal support 1 may be made of a porous metal to be permeable to gas, thereby supplying gas to the anode support layer 2 and the anode active layer 3.

[0015] The diameter of the through-hole 123 is preferably 100 μm to 500 μm. The thickness of the support portion 12 is preferably 50 μm to 500 μm, and the thickness of the frame portion 13 is not particularly limited except that it is thicker than the support portion 12, but is preferably 500 μm to 1000 μm, for example. When the thickness of the frame portion 13 is set to 500 μm, the thickness of the support portion 12 is formed to be thinner than 500 μm.

[0016] The metal support 1 is preferably made of Fe-Cr alloy steel (for example, stainless steel such as SUS304), but Ni-Cr alloy steel or the like can also be used. ２ ) and Al (Al ２ O ３ ) may be contained.

[0017] The anode support layer 2 (anode layer) is supported by a support portion 12 (the bottom surface of the recess 11) formed on the metal support 1, and is disposed on a support surface 121 of the support portion 12. The anode support layer 2 is housed in the recess 11, and is in contact with the bottom surface (support surface 121) and the inner wall surface of the recess 11.

[0018] The fuel electrode support layer 2 communicates with the flow surface 122 side of the support portion 12 via the through-holes 123 .

[0019] The anode support layer 2 is preferably porous. The porosity (100% - filling rate) of the anode support layer 2 is not particularly limited, but may be, for example, 20% to 70%. The thickness of the anode support layer 2 is not particularly limited, but may be, for example, 1 μm to 100 μm.

[0020] In the first embodiment, an anode gas (for example, hydrogen gas) is supplied to the fuel electrode support layer 2, and the fuel electrode support layer 2 functions as the anode of the solid oxide fuel cell.

[0021] The fuel electrode support layer 2 is made of NiO-GDC (gadolinium-doped ceria), Ni-GDC, NiO-YSZ (yttria-stabilized zirconia), Ni-YSZ, or CuO-CeO ２ , Cu—CeO ２ It can be made of composite materials such as:

[0022] The method for forming the fuel electrode support layer 2 is not particularly limited, and the layer can be formed by a screen printing method, a press molding method, a tape casting method, 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.

[0023] The anode active layer 3 is disposed on the anode support layer 2. The anode active layer 3 is housed in the recess 11 and contacts the inner side surface of the recess 11. The upper surface of the anode active layer 3 is generally flush with, for example, the upper surface of the frame 13. There are no particular limitations on the thickness of the anode active layer 3, but it can be, for example, 1 μm to 100 μm.

[0024] The anode active layer 3 preferably has oxide ion (oxygen ion) conductivity. The anode active layer 3 more preferably has electron conductivity. The anode active layer 3 can be made of YSZ, GDC, SSZ (scandium-stabilized zirconia), SDC (samarium-doped ceria), or the like. There are no particular limitations on the method for forming the anode active layer 3, and it can be formed by screen printing, press molding, tape casting, firing, spray coating, PVD, CVD, or the like.

[0025] The electrolyte layer 4 is disposed on the anode active layer 3. The electrolyte layer 4 is disposed so as to cover at least the anode active layer 3.

[0026] As described above, the electrolyte layer 4 contains oxygen ions (O ２－ ) The electrolyte layer 4 has gas barrier properties sufficient to prevent mixing of the anode gas and the cathode gas. The electrolyte layer 4 may have a multi-layer structure, but it is preferable that at least one layer is a dense layer. The porosity of the dense layer is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less. The thickness of the electrolyte layer 4 is not particularly limited, but can be, for example, 1 μm to 10 μm.

[0027] The electrolyte layer 4 can be made of YSZ, GDC, SSZ, SDC, LSGM, etc. The method for forming the electrolyte layer 4 is not particularly limited, and the electrolyte layer 4 can be formed by a screen printing method, a press molding method, a firing method, a spray coating method, a PVD method, a CVD method, etc.

[0028] The cathode layer 5 is disposed on the electrolyte layer 4. The electrolyte layer 4 is thus sandwiched between the cathode layer 5 and the anode active layer 3.

[0029] The air electrode layer 5 is formed in such a manner that its outer shape is housed inside the outer shape of the electrolyte layer 4 in a plan view, for example.

[0030] The air electrode layer 5 is preferably porous. The porosity of the air electrode layer 5 is not particularly limited, but may be, for example, 20% to 70%. The thickness of the air electrode layer 5 is not particularly limited, but may be, for example, 1 μm to 100 μm.

[0031] As described above, a cathode gas (air, oxygen) is supplied to the air electrode layer 5, and the air electrode layer 5 functions as a cathode of the solid oxide fuel cell. The air electrode layer 5 can be composed of LSCF, LSF, LSC, LNF, LSM, or the like. In particular, the air electrode layer 5 preferably contains a perovskite-type oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co, and Fe.

[0032] There are no particular limitations on the method for forming the air electrode layer 5, and it can be formed by screen printing, press molding, firing, spray coating, PVD, CVD, or the like.

[0033] FIG. 3 is a partial detailed view showing the support portion 12 and the fuel electrode support layer 2 of the electrochemical cell of the first embodiment.

[0034] As shown in FIG. 3 , the fuel electrode support layer 2 is disposed on the support surface 121 of the support portion 12 of the metal support 1 , but faces the through-hole 123 and communicates with the flow surface 122 through the through-hole 123 .

[0035] As described above, when the through hole 123 is formed using a fiber laser, the laser is irradiated onto the support surface 121 of the support portion 12 (the bottom surface of the recess 11 (Figure 1)) and the through hole 123 is formed in a manner that excavates from the support surface 121 of the support portion 12 to the flow surface 122 of the support portion 12 (the lower surface of the metal support 1).

[0036] At this time, a curved surface 123a is formed at the end (opening) of the through hole 123 on the support surface 121 side, connecting the inner wall of the through hole 123 and the bottom surface of the recess 11. The cross-sectional shape of the curved surface 123a is an arc shape. Due to this curved surface 123a, the end of the through hole 123 on the support surface 121 side has a tapered shape in which the diameter of the through hole 123 increases toward the support surface 121.

[0037] When the anode support layer 2 is formed on the support 12 having the through-holes 123, the material of the anode support layer 2 sinks into the openings of the through-holes 123, and as a result, the uneven shape caused by the sinking of the anode support layer 2 is transferred to the upper surface of the anode support layer 2 and to the electrolyte layer 4 formed on the upper surface of the anode support layer 2. If the layers are sintered while the electrolyte layer 4 has such an uneven shape, cracks may occur in the electrolyte layer 4, which may result in gas leakage (see FIG. 5 ).

[0038] However, in this embodiment, when the radius of curvature of the curved surface 123a formed in the through hole 123 is R and the thickness of the support portion 12 is T, the support portion 12 is formed so that R≦T / 3. This reduces the depth of the through hole 123 in the anode support layer 2 and reduces the steps of the uneven shape transferred to the electrolyte layer 4, thereby reducing cracks that occur in the electrolyte layer 4 during sintering and reducing gas leakage. Furthermore, as described above, by setting the diameter of the through hole 123 to 100 μm to 500 μm and the thickness of the support portion 12 to 50 μm to 500 μm, cracks that occur in the electrolyte layer 4 can be further reduced and gas leakage can be further reduced.

[0039] [Manufacturing Process of Electrochemical Cell] FIG. 4 is a flow diagram showing the manufacturing process of the electrochemical cell of the first embodiment.

[0040] As shown in FIG. 4, the manufacturing process of the electrochemical cell of this embodiment comprises steps S1 to S5.

[0041] In step S1, a recess 11 is formed in a metal support 1 (stainless steel plate). Any method can be used to form the recess 11, such as rolling, cutting, or electrical discharge machining. By forming the recess 11 in the metal support 1, the portion including the bottom surface of the recess 11 becomes a support portion 12, and the portion of the metal support 1 other than the recess 11 becomes a frame portion 13.

[0042] In step S2, a plurality of through holes 123 are formed in the support portion 12. The through holes 123 are formed, for example, by irradiating a fiber laser from the support surface 121 of the support portion 12 to engrave from the support surface 121 to the flow surface 122, or by performing a punching process using a press in which a punching member having an outer diameter equal to the inner diameter of the through holes 123 is passed from the support surface 121 to the flow surface 122.

[0043] In step S3, the anode support layer 2, the anode active layer 3, and the electrolyte layer 4 are laminated in this order on the support 12. Any method such as screen printing, tape casting, or spray coating can be used to form each layer.

[0044] In step S4, the anode support layer 2, the anode active layer 3, and the electrolyte layer 4 are fired at a high temperature (1000°C to 1500°C) in an inert gas (nitrogen, argon) or reducing atmosphere to prevent deformation of the stainless steel due to high-temperature oxidation.

[0045] In step S5, the air electrode layer 5 is laminated on the electrolyte layer 4 by, for example, screen printing, and the air electrode layer 5 is solidified by heat treatment at a predetermined temperature.

[0046] In steps S3 and S4, the anode support layer 2 may be laminated on the support surface 121 and fired, the anode active layer 3 may be formed on the fired anode support layer 2 and fired, and the electrolyte layer 4 may be laminated on the fired anode active layer 3 and fired. Alternatively, in steps S3 to S5, the anode support layer 2, the anode active layer 3, the electrolyte layer 4, and the air cathode layer 5 may be laminated in this order and then fired simultaneously.

[0047] Comparative Examples Fig. 5 is a cross-sectional view of an electrochemical cell of a first comparative example, and Fig. 6 is a cross-sectional view of an electrochemical cell of a second comparative example.

[0048] As shown in FIG. 5 , the first comparative example has a configuration in which a through-hole 123 (support portion 12) is formed in a metal support 1 without forming a recess 11, and an anode support layer 2, an anode active layer 3, an electrolyte layer 4, and an air cathode layer 5 are laminated on the support portion 12.

[0049] In Comparative Example 1, the electrolyte layer 4 is disposed so as to cover the upper surface of the anode active layer 3, the side surfaces of the anode active layer 3, the side surfaces of the anode support layer 2, and the outer periphery of the side surfaces of the anode support layer 2 on the lower surface of the frame 13. That is, the electrolyte layer 4, which has a dense structure with the metal support 1, seals the anode support layer 2 and the anode active layer 3. This effectively reduces gas leakage from the anode support layer 2 and the anode active layer 3 to the air electrode layer 5 side. The through-holes 123 are formed by a fiber laser.

[0050] In the first comparative example, the thickness of the metal support 1 is set to be thicker than 500 μm, for example. Therefore, the irradiation time of the fiber laser until the laser penetrates the metal support 1 is longer by the thickness, and the amount of heat applied to the area surrounding the through hole 123 of the metal support 1 increases, and the diameter of the opening of the through hole 123 on the support surface 121 side of the support portion 12 increases.

[0051] As described above, when the anode support layer 2 is formed on the support member 12 having the through-holes 123 with large opening diameters, the material of the anode support layer 2 sinks into the openings of the through-holes 123, as shown in Fig. 5, and as a result, the uneven shape caused by the sinking of the anode support layer 2 is transferred to the upper surface of the anode support layer 2 and to the electrolyte layer 4 formed on the upper surface. If the layers are sintered while the electrolyte layer 4 has such an uneven shape, cracks may occur in the electrolyte layer 4, which may result in gas leakage.

[0052] 6 (before sintering), the second comparative example has the same configuration as the first comparative example, but the thickness of the metal support 1 is set to be thinner than, for example, 500 μm. Therefore, the irradiation time of the fiber laser until the laser penetrates the metal support 1 is shortened by the thinner thickness, the amount of heat applied to the portion surrounding the through hole 123 of the metal support 1 is also suppressed, and the expansion of the diameter of the opening of the through hole 123 on the support surface 121 side of the support portion 12 is suppressed.

[0053] Therefore, in the second comparative example, the amount of sinking of the material of the fuel electrode support layer 2 into the opening of the through-hole 123 is reduced.

[0054] However, as shown in FIG. 6 (after sintering, only the outline is shown), in the second comparative example, the overall thickness of the metal support 1 is formed to be thin, and therefore, when each layer is fired, each layer shrinks in the planar direction, causing each layer and the metal support 1 (support portion 12) to warp (bend) in the thickness direction (toward each layer) as a whole, resulting in a decrease in yield.

[0055] On the other hand, in this embodiment, the thickness of the portion forming the support portion 12 is formed thin, as in the second comparative example, and therefore, the expansion of the diameter of the opening of the through hole 123 on the support surface 121 side is suppressed. Furthermore, the periphery of the support portion 12 is supported by the frame portion 13, which is thicker than the support portion 12, and therefore the surface rigidity of the support portion 12 is higher than in the second comparative example, and warping of the support portion 12 and each layer during firing is suppressed, thereby improving yield.

[0056] Second Embodiment Fig. 7 is a cross-sectional view of an electrochemical cell according to a second embodiment, and Fig. 8 is a bottom view of the electrochemical cell according to the second embodiment.

[0057] In the electrochemical cell of the second embodiment, the electrolyte layer 4 is disposed so as to cover the upper surface of the frame 13 and is joined to the upper surface of the frame 13. As a result, the electrolyte layer 4, which has a dense structure, closes the opening of the recess 11, and leakage of the anode gas supplied through the through-holes 123 to the upper surface side of the frame 13 can be reduced.

[0058] In the second embodiment, a coating 111 (passive coating) of an oxide of at least one metal selected from Al (aluminum), Co (cobalt), Mn (manganese), Cu (copper), Zr (zirconium), Si (silicon), and Ce (cerium) is formed on the bottom surface (support surface 121) and inner side surface of the recess 11. The coating 111 is formed by surface application using sputtering, spraying, plating, or the like. Placing the anode support layer 2 and anode active layer 3 in the recess 11 with this coating 111 improves the bonding strength between the metal support 1 and the anode support layer 2 and anode active layer 3. This suppresses gas leakage at the interfaces between the recess 11 and the anode support layer 2 and anode active layer 3, improving yield.

[0059] In the second embodiment, when forming the stainless steel used for the metal support 1, it is possible to dope the stainless steel base material with at least one metal selected from the group consisting of aluminum (Al), cobalt (Co), manganese (Mn), copper (Cu), zirconium (Zr), silicon (Si), and cerium (Ce), thereby forming a coating 111 (passive coating) made of the doped material (oxide of the doped material) on the stainless steel surface. In this case, the coating 111 is formed on the entire surface of the metal support 1, thereby suppressing gas leakage at the interface between the electrolyte layer 4 and the frame 13 and further improving yield. As described above, the electrochemical cell of the first embodiment is made of stainless steel, and a coating 111 (passive coating) made of chromium oxide (not shown in FIG. 1 ) is formed on the surface of the stainless steel.

[0060] In the second embodiment, the support portion 12 includes a thin portion 127 in which a through hole 123 is formed, and a thick portion 124 that is thicker than the thin portion 127. In Figures 7 and 8, the thick portion 124 does not have a through hole 123 formed therein, but the thick portion 124 may also have a through hole 123 formed therein.

[0061] The thick portion 124 is flush with the thin portion 127 on the support surface 121 and protrudes from the thin portion 127 on the flow surface 122 .

[0062] The thick portion 124 has a first beam 125 that is parallel to the long sides of the support portion 12 and passes through the center of the support portion 12 when viewed in plan, and a second beam 126 that is parallel to the short sides of the support portion 12 and intersects (is perpendicular to) the first beam 125 at the center of the support portion 12. Both ends of the first beam 125 and both ends of the second beam 126 are connected to the frame portion 13.

[0063] As shown in FIG. 8, the thin portion 127 is formed as a plurality of (four) regions partitioned by the first beam 125 and the second beam 126 .

[0064] As shown in FIG. 7, the thick portion 124 (first beam 125, second beam 126) and the frame portion 13 form the same plane on the lower surface of the metal support 1, but may have a step.

[0065] As described above, by forming the cross-shaped first beam 125 and second beam 126 in the support portion 12, the surface rigidity of the metal support body 1 is improved, and in particular, by connecting the first beam 125 and the second beam 126 to the frame portion 13, the surface rigidity is further improved, thereby reducing the occurrence of warping (curving) and undulation during sintering and further improving the yield.

[0066] 9 is a cross-sectional view of an electrochemical cell according to a third embodiment. In the electrochemical cell according to the third embodiment, the anode support layer 2, the anode active layer 3, the electrolyte layer 4, and the cathode layer 5 are disposed on the flow surface 122 side of the metal support 1, rather than on the recess 11 side.

[0067] The through hole 123 is formed using a fiber laser or the like as described above, but it can be formed not only by digging from the support surface 121 of the support portion 12 (the bottom surface of the recess 11) toward the flow surface 122 of the support portion 12, but also by digging from the flow surface 122 toward the support surface 121.

[0068] In this case, however, burrs are generated at the openings of the support surface 121 of the through holes 123 , protruding away from the bottom surfaces of the recesses 11 in the thickness direction of the metal support body 1 .

[0069] If the anode support layer 2, the anode active layer 3, and the electrolyte layer 4 are arranged as in the first embodiment while these burrs are present, the uneven shape of the burrs will be transferred to the electrolyte layer 4 as well, and cracks will occur in the electrolyte layer 4 when the layers are fired, which could result in gas leakage.

[0070] Therefore, in the third embodiment, when the through-holes 123 are formed by digging from the flow surface 122 toward the support surface 121 (the bottom surface of the recess 11), the flow surface 122 serves as the support surface 121, and the anode support layer 2, the anode active layer 3, the electrolyte layer 4, and the air cathode layer 5 are disposed on the support surface 121. Note that the electrolyte layer 4 is configured to seal the anode support layer 2 and the anode active layer 3, as in the above-described comparative example 1.

[0071] In the third embodiment, an anode gas is supplied to the through-holes 123 that open to the recesses 11 of the metal support 1 .

[0072] 10 is a cross-sectional view of an electrochemical cell according to a fourth embodiment. In the fourth embodiment, the metal support 1 is formed by joining two metal plates together.

[0073] The metal support 1 includes a first metal plate 1a in which the through hole 123 is formed, and a frame-shaped second metal plate 1b having an opening having the shape of the recess 11 when viewed from above.

[0074] Then, the main surface of the first metal plate 1a and the main surface of the second metal plate 1b are joined together in a state where the region of the first metal plate 1a where the through hole 123 is formed (support portion 12) and the region of the second metal plate 1b where the opening is formed face each other, thereby forming the metal support 1 having the recess 11. The first metal plate 1a and the second metal plate 1b can be joined by any joining method such as welding or solid-state welding.

[0075] The through-holes 123 may also be formed after the first metal plate 1a and the second metal plate 1b are joined together.

[0076] By forming the metal support 1 as described above, the recesses 11 are formed by assembly, so there is no need to form the recesses 11 by directly carving them into the metal support 1, and it is possible to reduce variations in the depth of the recesses 11. Furthermore, since the metal support 1 can be formed without preparing a metal material with the same thickness as the thickness of the metal support 1, it is possible to reduce costs.

[0077] In the fourth embodiment, the anode support layer 2, anode active layer 3, electrolyte layer 4, and air cathode layer 5 are not shown, but the configuration and manufacturing process are the same as those of the first embodiment.

[0078] [Solid Oxide Electrolysis Cell] FIG. 11 is a schematic diagram of the electrochemical cell of this embodiment used as a solid oxide electrolysis cell.

[0079] The electrochemical cell of this embodiment can also be used as a solid oxide electrolysis cell. Fig. 11 shows a solid oxide electrolysis cell using the electrochemical cell of the first embodiment, but the electrochemical cells of the second to fourth embodiments can also be applied.

[0080] 11, water is supplied to the anode support layer 2 side, and a DC voltage is applied to the cell body, with the cathode layer 5 on the positive side of the DC voltage and the metal support 1 (anode support layer 2 and anode active layer 3) on the negative side of the DC voltage.

[0081] Water molecules (2H ２ O) reacts with hydrogen ions (4H ＋ ) and oxygen ions (2O ２－ )

[0082] Hydrogen ion (4H ＋ ) is converted into hydrogen molecules (2H) by the supply of electrons in the anode support layer 2 or the anode active layer 3. ２ )

[0083] Oxygen ions (2O ２－ ) is conducted through the electrolyte layer 4 to reach the air electrode layer 5, where electrons are taken away, resulting in oxygen molecules (O ２ )

[0084] Effect of this embodiment The electrochemical cell of this embodiment includes a cell main body 6 in which a first electrode layer (anode support layer 2, anode active layer 3), an electrolyte layer 4, and a second electrode layer (air electrode layer 5) are laminated in this order, and a metal support 1 that supports the cell main body 6. The metal support 1 includes a support surface 121 that supports one main surface of the cell main body 6 (e.g., the main surface on the anode support layer 2 side), and a support part 12 that includes an opposite surface (flow surface 122) of the support surface 121 and allows gas to communicate between the support surface 121 and the opposite surface (flow surface 122). A frame part 13 is arranged to surround the outer periphery of the support part 12, and the thickness of the support part 12 is smaller than the thickness of the frame part 13.

[0085] With the above configuration, the thickness of the portion forming support 12 is made thinner than frame 13, so when through-holes 123 are formed in support 12, the diameter of the openings of through-holes 123 on the support surface 121 side is suppressed from increasing. This reduces sinking of the first electrode layer (anode support layer 2, anode active layer 3) into through-hole 123, and also reduces the transfer of unevenness caused by this sinking to electrolyte layer 4. This suppresses the occurrence of cracks in electrolyte layer 4 during firing, thereby reducing gas leakage from electrolyte layer 4. Furthermore, because the periphery of support 12 is supported by frame 13, which is thicker than support 12, the surface rigidity of support 12 is improved, suppressing warping of support 12, the first electrode layer (anode support layer 2, anode active layer 3), electrolyte layer 4, and air cathode layer 5 during firing, and improving yield.

[0086] In this embodiment, the support portion 12 has through holes 123 that allow gas to communicate between the support surface 121 and the opposite surface (flow surface 122).

[0087] With the above configuration, the support portion 12 can be constructed with a simple configuration.

[0088] In this embodiment, the diameter of the through-hole 123 is 500 μm or less.

[0089] The above configuration reduces sinking of the first electrode layer (anode support layer 2, anode active layer 3) into through-holes 123, and similarly reduces gas leakage in electrolyte layer 4.

[0090] In this embodiment, the thickness of the support portion 12 is 500 μm or less.

[0091] With the above configuration, by suppressing the expansion of the diameter of the opening of the through hole 123 on the support surface 121 side during the formation of the through hole 123, it is possible to reduce sinking of the first electrode layer (anode support layer 2, anode active layer 3) into the through hole 123, and similarly to the above, reduce gas leakage in the electrolyte layer 4.

[0092] In this embodiment, the radius of curvature (R) of the curved surface 123a that connects the support surface 121 formed around (opening of) the through hole 123 of the support surface 121 of the support portion 12 and the inner wall of the through hole 123 is 1 / 3 or less of the thickness (T) of the support portion 12.

[0093] The above configuration reduces sinking of the first electrode layer (anode support layer 2, anode active layer 3) into through-holes 123, and similarly reduces gas leakage in electrolyte layer 4.

[0094] In this embodiment, the material of the metal support 1 is stainless steel.

[0095] With the above configuration, when a fiber laser is irradiated to form a through hole 123 in the metal support 1 (support portion 12), the portion irradiated with the laser is exposed to high temperatures. However, if the stainless steel contains chromium, a coating 111 (passivation coating) (FIG. 7) is immediately formed on the exposed portion, which suppresses oxidation (deterioration) of the portion inside the coating 111. This reduces gas leakage through portions of the metal support 1 other than the through hole 123.

[0096] In this embodiment, the metal support 1 has a recess 11 whose bottom surface is the support surface 121 and whose inner side surface is a step formed in the thickness direction of the metal support 1 between the frame portion 13 and the support portion 12, the first electrode layer (anode support layer 2, anode active layer 3) is accommodated in the recess 11, and the electrolyte layer 4 is exposed from the recess 11 and is disposed so as to close the opening of the recess 11 and is joined to the frame portion 13.

[0097] With the above-described configuration, the metal support 1 and the electrolyte layer 4 having a dense structure seal the first electrode layer (anode support layer 2, anode active layer 3), thereby reducing gas leakage from the first electrode layer (anode support layer 2, anode active layer 3).

[0098] In this embodiment, the metal support 1 has a recess 11 whose bottom surface is the support surface 121 and whose inner side surface is a step formed in the thickness direction of the metal support 1 between the frame portion 13 and the support portion 12, and the support portion 12 includes a thin-walled portion 127 in which a through hole 123 is formed, and a thick-walled portion 124 that is thicker than the thin-walled portion 127.

[0099] The above-described configuration increases the surface rigidity of the support portion 12, and reduces warping of the entire electrochemical cell that may occur during sintering.

[0100] In this embodiment, the thick-walled portion 124 includes a first beam 125 that extends in one direction and is flush with the thin-walled portion 127 on the support surface 121, and is formed so as to protrude more than the thin-walled portion 127 on the opposite surface (flow surface 122), and a second beam 126 that forms the same plane as the thin-walled portion 127 on the support surface 121, and is formed so as to protrude more than the thin-walled portion 127 on the opposite surface (flow surface 122), and intersects with the first beam 125, and the thin-walled portion 127 is formed as multiple regions separated by the first beam 125 and the second beam 126 on the support surface 121.

[0101] With the above configuration, the first beam 125 and the second beam 126 are connected to the frame 13, and a certain level of rigidity is achieved between the first beam 125, the second beam 126, and the frame 13. Therefore, the thin-walled portion 127 having the through-hole 123 is supported by the frame 13, the first beam 125, and the second beam 126, dramatically improving the surface rigidity of the thin-walled portion 127. Therefore, the surface rigidity of the thin-walled portion 127 is increased, and warpage of the entire electrochemical cell that may occur during sintering can be reduced with high precision.

[0102] In this embodiment, the metal support 1 has a recess 11 having a support surface 121 as its bottom surface and a step formed in the thickness direction of the metal support 1 between the frame portion 13 and the support portion 12 as its inner side surface, and the first electrode layer (anode support layer 2, anode active layer 3) is housed in the recess 11 and is joined to the bottom surface (support surface 121) and the inner side surface, and a coating 111 ( FIG. 7 ) containing at least one of aluminum, cobalt, manganese, copper, zirconium, and cerium is formed on the bottom surface (support surface 121) and the inner side surface.

[0103] In the above configuration, the metal support 1 having the coating is formed by doping the stainless steel base material that forms the metal support 1 with the coating material. Then, when the anode support layer 2 and the anode active layer 3 are disposed in the recess 11 having the coating, the bonding strength between the metal support 1 and the anode support layer 2 and the anode active layer 3 is improved. This suppresses the occurrence of gas leakage at the interface between the recess 11 and the anode support layer 2 and the anode active layer 3, improving the yield. Furthermore, because the coating is formed over the entire surface of the metal support 1, it also suppresses the occurrence of gas leakage at the interface between the electrolyte layer 4 and the frame 13, improving the yield.

[0104] The solid oxide fuel cell of this embodiment is a solid oxide fuel cell that uses the above-described electrochemical cell, in which support 12 supports the main surface of the electrochemical cell on the side of the first electrode layer (anode support layer 2, anode active layer 3), electrolyte layer 4 is formed of an oxygen ion conductive oxide, and cathode gas (air, oxygen) is supplied to the second electrode layer (air cathode layer 5), and anode gas (hydrogen) is supplied to the first electrode layer (anode support layer 2, anode active layer 3) via support 12, thereby enabling cell main body 6 to generate electricity.

[0105] With the above configuration, a solid oxide fuel cell can be constructed with a simple configuration.

[0106] The solid oxide electrolysis cell of this embodiment is a solid oxide electrolysis cell using the above-described electrochemical cell, in which a support 12 supports the main surface of the electrochemical cell on the side of the first electrode layer (anode support layer 2, anode active layer 3), the electrolyte layer 4 is formed of an oxygen ion conductive oxide, water is supplied to the first electrode layer (air cathode layer 5) via the support 12, and a voltage is applied between the first electrode layer (anode support layer 2, anode active layer 3) and the second electrode layer (air cathode layer 5), thereby enabling electrolysis of the water supplied to the first electrode layer (anode support layer 2, anode active layer 3).

[0107] With the above configuration, a solid oxide electrolysis cell can be constructed with a simple configuration.

[0108] The method for manufacturing an electrochemical cell of this embodiment is a method for manufacturing an electrochemical cell by laminating a first electrode layer (anode support layer 2, anode active layer 3), an electrolyte layer 4, and a second electrode layer (air cathode layer 5) in this order on a metal support 1, in which a recess 11 is formed on one main surface of the metal support 1, a plurality of through holes 123 that penetrate the metal support 1 in the thickness direction are formed in an area of ​​the metal support 1 that will become the bottom surface of the recess 11, and the first electrode layer (anode support layer 2, anode active layer 3), the electrolyte layer 4, and the second electrode layer (air cathode layer 5) are laminated in this order on the bottom surface or on the surface of the metal support 1 opposite to the bottom surface.

[0109] In the above method, the region of metal support 1 where recess 11 is formed becomes support portion 12 that supports the first electrode layer (anode support layer 2, anode active layer 3), and the region surrounding support portion 12 becomes frame portion 13 that is thicker than support portion 12. The above method allows the thickness of the portion that forms support portion 12 to be thinner than frame portion 13, so that when through holes 123 are formed in support portion 12, the diameter of the opening of through hole 123 on the support surface 121 side is suppressed from increasing. This reduces sinking of the first electrode layer (anode support layer 2, anode active layer 3) into through hole 123 and also reduces the transfer of the uneven shape caused by this sinking to electrolyte layer 4. This suppresses the occurrence of cracks in electrolyte layer 4 during firing, thereby reducing gas leakage in electrolyte layer 4. Furthermore, since the periphery of the support portion 12 is supported by the frame portion 13, which is thicker than the support portion 12, the surface rigidity of the support portion 12 is improved, which suppresses warping of the support portion 12, the first electrode layer (anode support layer 2, anode active layer 3), the electrolyte layer 4, and the air cathode layer 5 during firing, thereby improving yield.

[0110] In this embodiment, when the through-hole 123 is formed by digging from the bottom surface toward the opposite surface, the first electrode layer (anode support layer 2, anode active layer 3), electrolyte layer 4, and second electrode layer (air electrode layer 5) are laminated in this order on the bottom surface, and when the through-hole 123 is formed by digging from the opposite surface toward the bottom surface, the first electrode layer (anode support layer 2, anode active layer 3), electrolyte layer 4, and second electrode layer (air electrode layer 5) are laminated in this order on the opposite surface.

[0111] In the above method, when through hole 123 is formed by digging from the bottom surface (support surface 121) toward the opposite surface, a burr is generated at the opening of through hole 123 on the opposite surface, protruding away from the opposite surface in the thickness direction of metal support 1. Conversely, when through hole 123 is formed by digging from the opposite surface toward the bottom surface (support surface 121), a burr is generated at the opening of through hole 123 on the bottom surface (support surface 121), protruding away from the bottom surface of recess 11 in the thickness direction of metal support 1. If the first electrode layer (anode support layer 2, anode active layer 3) and electrolyte layer 4 are placed on this burr, the uneven shape of the burr is also transferred to electrolyte layer 4, which may cause cracks in electrolyte layer 4 when the layers are fired, resulting in gas leaks. Therefore, by disposing the first electrode layer (anode support layer 2, anode active layer 3) and electrolyte layer 4 on a surface without burrs as in the above method, it is possible to prevent the uneven shape of the burrs from being transferred to the electrolyte layer 4 and reduce gas leakage from the electrolyte layer 4.

[0112] In this embodiment, the metal support 1 includes a first metal plate 1a in which a through hole 123 is formed, and a frame-shaped second metal plate 1b having an opening shaped like the recess 11 when viewed in plan, and the metal support 1 having the recess 11 is formed by joining the main surface of the second metal plate 1b to the main surface of the first metal plate 1a.

[0113] According to the above method, the recesses 11 are formed by assembly, so there is no need to form the recesses 11 by directly carving them into the metal support 1, and it is possible to reduce variations in the depth of the recesses 11. Furthermore, since the metal support 1 can be formed without preparing a metal material with the same thickness as the thickness of the metal support 1, it is possible to reduce costs.

[0114] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. An electrochemical cell comprising: a cell body portion formed by laminating a first electrode layer, an electrolyte layer, and a second electrode layer in this order; and a metal support supporting the cell body portion, wherein the metal support includes: a support portion including a support surface supporting one main surface of the cell body portion and an opposite surface of the support surface, and allowing gas to communicate between the support surface and the opposite surface; and a frame portion arranged to surround the outer periphery of the support portion, wherein the thickness of the support portion is formed to be thinner than the thickness of the frame portion.

2. The electrochemical cell according to claim 1, wherein the support portion has through-holes that allow gas to communicate between the support surface and the opposite surface.

3. The electrochemical cell according to claim 2, wherein the diameter of the through holes is 500 μm or less.

4. The electrochemical cell according to claim 2, wherein the thickness of the support portion is 500 μm or less.

5. An electrochemical cell as described in claim 2, wherein the radius of curvature of the curved surface that connects the support surface formed around the through hole of the support part to the inner wall of the through hole is 1 / 3 or less of the thickness of the support part.

6. The electrochemical cell according to claim 1, wherein the material of the metal support is stainless steel.

7. The electrochemical cell according to claim 1, wherein the metal support has a recess whose bottom surface is the support surface and whose inner side surface is a step formed in the thickness direction of the metal support between the frame and the support, the first electrode layer is accommodated in the recess, and the electrolyte layer is exposed from the recess and is positioned so as to close the opening of the recess and is joined to the frame.

8. The electrochemical cell according to claim 2, wherein the metal support has a recess whose bottom surface is the support surface and whose inner side surface is a step formed in the thickness direction of the metal support between the frame portion and the support portion, and the support portion includes a thin-walled portion in which the through hole is formed, and a thick-walled portion that is thicker than the thin-walled portion.

9. An electrochemical cell as described in claim 8, wherein the thick portion includes a first beam that is flush with the thin portion on the support surface, is formed so as to protrude further than the thin portion on the opposite surface, and extends in one direction, and a second beam that is flush with the thin portion on the support surface, is formed so as to protrude further than the thin portion on the opposite surface, and intersects with the first beam, and the thin portion is formed as a plurality of regions partitioned by the first beam and the second beam on the support surface.

10. The electrochemical cell described in claim 1, wherein the metal support has a recess whose bottom surface is the support surface and whose inner side surface is a step formed in the thickness direction of the metal support between the frame portion and the support portion, the first electrode layer is accommodated in the recess and joined to the bottom surface and the inner side surface, and a coating containing at least one of aluminum, cobalt, manganese, copper, zirconium, and cerium is formed on the bottom surface and the inner side surface.

11. A solid oxide fuel cell using an electrochemical cell according to any one of claims 1 to 10, wherein the support part supports the main surface of the electrochemical cell on the side of the first electrode layer, the electrolyte layer is formed from an oxygen ion conductive oxide, and a cathode gas is supplied to the second electrode layer and an anode gas is supplied to the first electrode layer via the support part, thereby enabling the cell main body to generate electricity.

12. A solid oxide electrolysis cell using the electrochemical cell according to any one of claims 1 to 10, wherein the support part supports a main surface of the electrochemical cell on the side of the first electrode layer, the electrolyte layer is formed of an oxygen ion conductive oxide, and water is supplied to the first electrode layer via the support part, and a voltage is applied between the first electrode layer and the second electrode layer, thereby enabling electrolysis of the water supplied to the first electrode layer.

13. A method for manufacturing an electrochemical cell formed by laminating a first electrode layer, an electrolyte layer, and a second electrode layer in this order on a metal support, comprising: forming a recess on one main surface of the metal support; forming a plurality of through holes that penetrate the metal support in the thickness direction in an area of ​​the metal support that will become the bottom surface of the recess; and laminating the first electrode layer, the electrolyte layer, and the second electrode layer in this order on the bottom surface or on the opposite surface of the metal support that faces the bottom surface.

14. A method for manufacturing an electrochemical cell as described in claim 13, wherein when the through-hole is formed by digging from the bottom surface toward the opposite surface, the first electrode layer, the electrolyte layer, and the second electrode layer are stacked in this order on the bottom surface, and when the through-hole is formed by digging from the opposite surface toward the bottom surface, the first electrode layer, the electrolyte layer, and the second electrode layer are stacked in this order on the opposite surface.

15. A method for manufacturing an electrochemical cell as described in claim 13, wherein the metal support includes a first metal plate in which the through hole is formed and a frame-shaped second metal plate having an opening that has a shape similar to the recess when viewed in plan, and the metal support having the recess is formed by joining a main surface of the second metal plate to a main surface of the first metal plate.

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