Electrochemical cell and method for manufacturing the same

Abstract

To provide an electrochemical cell that includes a support achieving both mechanical strength and gas permeability at a high level.SOLUTION: An electrochemical cell 100 disclosed herein includes a plate-shaped support 10 that supports a laminated structure producing an electrochemical reaction. The support 10 of the electrochemical cell 100 disclosed herein includes a plurality of first holes 12 extending from a bottom face 10a of the support 10 toward a top face 10b thereof, and a plurality of second holes 16 which is formed inside a partition wall 14 separating each of the plurality of first holes 12. In the support 10, a circulation property of a fuel gas in a film thickness direction of the support 10 is improved by the first holes 12, and also the fuel gas passing through the first holes 12 can be preferably diffused by the second holes 16. As a result, preferable gas permeability can be obtained without significantly increasing an open porosity ratio of the support 10, so that both mechanical strength and gas permeability of the support can be achieved at a high level.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrochemical cell and a method for manufacturing the same.

Background Art

[0002] A solid oxide fuel cell (SOFC) has advantages such as high power generation efficiency and low environmental impact, and its demand has been increasing in recent years. This SOFC has, for example, a laminated structure that exhibits an electrochemical reaction in which a fuel electrode (anode), a solid electrolyte layer, and an air electrode (cathode) are laminated in this order. In such a SOFC structure, oxygen (O2) in the oxygen-containing gas (typically air) supplied to the air electrode is reduced to oxygen ions (O 2- -). Such oxygen ions move through the solid electrolyte layer to the fuel electrode and react with the fuel gas (e.g., hydrogen (H2)) supplied to the fuel electrode. At this time, electrons are released to an external load to generate electrical energy, and water vapor (H2O) is generated at the fuel electrode. On the other hand, this laminated structure functions as a solid oxide electrolysis cell (SOEC) by applying reverse current and can also generate hydrogen gas from water (water vapor). Specifically, water vapor is decomposed by applying current in a state where water vapor is supplied to the anode of the laminated structure that exhibits the above-described electrochemical reaction. At this time, oxygen gas is generated at the cathode and hydrogen gas is generated at the anode. In this specification, a cell including a laminated structure that functions as such a SOFC and SOEC is referred to as an "electrochemical cell".

[0003] In this type of electrochemical cell, a ceramic support may be disposed below the fuel electrode in order to maintain the shape of the stacked structure. Here, in the electrochemical cell having the above configuration, it is required to uniformly supply a gas (fuel gas or water vapor) to the entire area of the anode. Further, when used as an SOEC, it is necessary to efficiently recover the hydrogen gas generated at the anode. For these reasons, the support below the anode is required to have good gas permeability. Therefore, a porous body having a large number of pores is usually used for the support of the electrochemical cell. For example, Patent Document 1 discloses an oxygen ion transport composite element in which a porous layer (support) is disposed below a dense layer. In this Patent Document 1, a metal plate having pores formed by a beam drilling method or the like is disposed below the porous layer. Further, another example of an electrochemical cell in which a support layer having a plurality of pores is disposed below a dense layer is described in Patent Document 2.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in recent years, in order to improve the operating efficiency of an electrochemical cell, it has been required to further improve the gas permeability of the support. However, if the open porosity of the support is increased too much for the purpose of improving the gas permeability, the mechanical strength of the support will be greatly reduced, and there is a risk that the shape of the cell structure cannot be maintained. That is, in the support of an electrochemical cell, there is a trade-off relationship between gas permeability and mechanical strength, and it has been difficult to balance these characteristics. The present invention has been made to solve such problems, and an object thereof is to provide an electrochemical cell having a support in which mechanical strength and gas permeability are compatible at a high level.

Means for Solving the Problems

[0006] In order to achieve the above object, an electrochemical cell having the following configuration is provided by the technology disclosed herein.

[0007] The electrochemical cell disclosed herein includes a plate-shaped support that supports a laminated structure that exhibits an electrochemical reaction. And the support of the electrochemical cell disclosed herein includes a plurality of first holes extending from the bottom surface to the top surface of the support, a partition wall separating each of the plurality of first holes, and a plurality of second holes formed inside the partition wall.

[0008] First, the effects when the electrochemical cell with the above configuration is used as an SOFC will be described. In the support of this electrochemical cell, first holes extending from the bottom surface to the top surface of the support are formed. By means of such first holes, sufficient flow of fuel gas in the membrane thickness direction of the support can be ensured. And inside the partition walls separating each of the first holes, a plurality of second holes are formed. Thereby, the fuel gas passing through the first holes can be suitably diffused in the planar direction. As a result, the fuel gas can be efficiently supplied to the laminated structure (typically, the anode of the laminated structure), and the power generation efficiency of the SOFC can be improved. On the other hand, the support with the above configuration can also contribute to the improvement of the operating efficiency of the SOEC. Specifically, in the electrochemical cell disclosed herein, since the hydrogen gas generated in the laminated structure can be collected into the first holes via the second holes, the recovery efficiency of hydrogen gas can be improved. And according to the experiments conducted by the present inventor, it has been confirmed that the support having these two types of ventilation holes can ensure suitable gas permeability without increasing the open pore ratio which is the cause of the decrease in mechanical strength. That is, according to the technology disclosed herein, the trade-off relationship in the support can be broken, and both mechanical strength and gas permeability can be achieved at a high level.

[0009] In a preferred embodiment of the electrochemical cell disclosed herein, the first holes are non-through holes that do not reach the top surface of the support. Thereby, the flatness of the top surface of the support can be maintained, and the formation of the laminated structure can be facilitated. Also, according to this embodiment, the permeation distance of the gas passing through the first holes is set to an appropriate length, and the gas diffusion by the second holes is performed more efficiently, so that the power generation efficiency of the SOFC can be further improved.

[0010] Further, in the embodiment where the first holes are non-through holes, the length of the first holes in the thickness direction of the support is preferably 10% or more and 95% or less of the thickness of the support. Thereby, the gas permeability in the membrane thickness direction of the support can be suitably improved, and the flatness of the top surface of the support can be suitably maintained.

[0011] Furthermore, in an embodiment where the first hole is a non-through hole, the first hole preferably has a tapered shape in which the cross-sectional area decreases toward the upper surface of the support. This prevents the formation of a convex portion corresponding to the upper surface of the first hole on the upper surface of the support, and can more suitably maintain the flatness of the upper surface of the support.

[0012] In a preferred embodiment of the electrochemical cell disclosed herein, the planar shape of the first hole at the bottom surface of the support is substantially circular or substantially rectangular. The planar shape of the first hole is not particularly limited, and these shapes can be adopted without particular limitation.

[0013] In a preferred embodiment of the electrochemical cell disclosed herein, the average opening length of the first hole at the bottom surface of the support is 20 μm or more and 300 μm or less. This can achieve both a higher level of mechanical strength and gas permeability of the support.

[0014] In a preferred embodiment of the electrochemical cell disclosed herein, the formation density of the first holes on the bottom surface of the support is 100 holes / cm 2 or more and 10,000 holes / cm 2 or less. This can achieve both a higher level of mechanical strength and gas permeability of the support.

[0015] In a preferred embodiment of the electrochemical cell disclosed herein, the average value of the formation pitch of the first holes is 80 μm or more and 980 μm or less. This can achieve both a higher level of mechanical strength and gas permeability of the support.

[0016] In a preferred embodiment of the electrochemical cell disclosed herein, the open porosity of the partition wall in the oxidized state is 30% or less. This can sufficiently ensure the mechanical strength of the support.

[0017] In a preferred embodiment of the electrochemical cell disclosed herein, the laminated structure includes an anode formed on the upper surface of the support, a solid electrolyte layer formed on the upper surface of the anode, and a cathode formed on the upper surface of the solid electrolyte layer. In the technology disclosed herein, the "laminated structure that exhibits an electrochemical reaction" can have the above-described configuration.

[0018] Also, as another aspect of the technology disclosed herein, a method for manufacturing an electrochemical cell (hereinafter, also simply referred to as the "manufacturing method") is provided. Such a manufacturing method is a method for manufacturing an electrochemical cell including a plate-shaped support that supports a laminated structure exhibiting an electrochemical reaction. And the manufacturing method disclosed herein includes a step of preparing a raw material for a support including at least an inorganic material, a binder, and a pore-forming material, a step of forming the raw material for the support into a sheet shape to produce a green sheet for the support, and a step of pressing an opening jig having a plurality of protrusions against the bottom surface of the green sheet for the support to form a plurality of first holes extending from the bottom surface to the top surface of the green sheet for the support, and a step of firing the green sheet for the support to burn out the pore-forming material and form second holes inside partitions separating each of the plurality of first holes. The electrochemical cell manufactured by such a manufacturing method has a support in which mechanical strength and gas permeability are compatible at a high level.

[0019] Also, in a preferred embodiment of the manufacturing method disclosed herein, the plurality of protrusions formed on the opening jig are conical. Thereby, it is possible to prevent a convex portion corresponding to the upper surface of the protrusion of the opening jig from being formed on the upper surface of the support, and it is possible to easily form a laminated structure on the upper surface of the support.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

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Figure 9

Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings as appropriate. In addition, matters other than those specifically mentioned in this specification, which are necessary for the implementation of the technology disclosed herein (for example, detailed materials and manufacturing methods of each layer except the support), can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field. In the following drawings, members and parts having the same function are denoted by the same reference numerals and described, and duplicate descriptions may be omitted or simplified. In this specification, the notation "X to Y (where X and Y are arbitrary values)" indicating a numerical range means "X or more and Y or less".

[0022] [First Embodiment] 1. Electrochemical Cell First, an embodiment (first embodiment) of the electrochemical cell disclosed herein will be described. FIG. 1 is a diagram schematically showing the electrochemical cell according to the first embodiment. Further, FIG. 2 is a partial cross-sectional perspective view showing the support of the electrochemical cell according to the first embodiment. As shown in FIG. 1, the electrochemical cell 100 according to the present embodiment includes a plate-shaped support 10 that supports a laminated structure that exhibits an electrochemical reaction. And the said laminated structure in this embodiment is comprised by laminating | stacking a fuel electrode 20, a solid electrolyte layer 30, and an air electrode 40 in this order. Hereinafter, each member will be described.

[0023] (1) Support The support 10 is a member that supports the laminated structure (fuel electrode 20, solid electrolyte layer 30, and air electrode 40) of the electrochemical cell 100. The material of such a support 10 only needs to have a predetermined heat resistance and strength, and conventionally known inorganic materials that can be used in this type of electrochemical cell can be used without particular limitation. Examples of the inorganic materials included in such a support 10 include stabilized zirconias such as yttria-stabilized zirconia (YSZ), calcia-stabilized zirconia (CSZ), and scandia-stabilized zirconia (ScSZ), and cerium oxides such as gadolinia-doped ceria (GDC) and samaria-doped ceria (SDC). Further, metal composite oxides such as lanthanum strontium titanium composite oxide (LST), metal oxides such as nickel oxide (NiO) and copper oxide (CuO), and alloy materials such as nickel-chromium-iron alloy (NCF) and nickel-chromium-cobalt alloy (NCC) can also be used for the support 10.

[0024] Note that the support 10 may be a conductive support or an insulating support. When constructing a conductive support, it is preferable to mix a conductive material as the inorganic material of the support. Among the materials described above, nickel oxide (NiO) is suitable as the inorganic material when constructing a conductive support because it functions as a conductive material when reduced with hydrogen gas before use in an SOFC. Even when constructing a conductive support, a ceramic material having no conductivity (for example, YSZ, etc.) may be added. In this case, the mixing ratio (mass ratio) of the conductive material and the ceramic material is preferably in the range of 3:7 to 7:3, for example, about 5:5. The technology disclosed herein can be particularly preferably applied to an electrochemical cell provided with a conductive support. When the open porosity is increased for the purpose of improving the gas permeability of such a conductive support, not only the mechanical strength but also the conductivity may decrease. However, according to the technology disclosed herein, the gas permeability can be improved without significantly increasing the open porosity, so that the decrease in conductivity can also be preferably suppressed.

[0025] As shown in Fig. 1, the support 10 according to the present embodiment is a plate-shaped member. Note that the shape of the support 10 in plan view is not particularly limited, and it may be circular or rectangular. Also, since the mechanical strength of the support 10 improves as the film thickness of the support 10 increases, the cell structure can be appropriately held. From such a viewpoint, the film thickness of the support 10 is preferably 150 μm or more, more preferably 200 μm or more, and particularly preferably 250 μm or more. On the other hand, as the film thickness of the support 10 decreases, the supply of fuel gas to the laminated structure (typically the fuel electrode 20) tends to become easier. From such a viewpoint, the upper limit of the film thickness of the support 10 is preferably 600 μm or less, more preferably 500 μm or less, and particularly preferably 400 μm or less.

[0026] Also, as shown in Figs. 1 and 2, in the electrochemical cell 100 according to the present embodiment, a plurality of first holes 12 and second holes 16 are provided in the support 10. The pore structure of such a support 10 will be described in detail later.

[0027] (2) Fuel Electrode (Anode) The fuel electrode (anode) 20 is formed on the upper surface 10b of the support 10. This fuel electrode 20 is, for example, a porous body containing a conductive material (a material having catalytic activity). It is preferable that this fuel electrode 20 has a large number of pores. Thereby, fuel gas can be efficiently supplied to the entire area of the fuel electrode 20. Note that the open porosity of the fuel electrode 14 is preferably 5 to 20% (for example, about 15%). Also, regarding the material of the fuel electrode 20, a conventionally known conductive material that can be used for this type of electrochemical cell can be used without particular limitation. As an example of the conductive material of the fuel electrode 20, metals such as nickel (Ni), copper (Cu), gold (Au), platinum (Pt), palladium (Pd), ruthenium (Ru), cobalt (Co), lanthanum (La), strontium (Sr), titanium (Ti), etc., or metal oxides thereof can be mentioned. Further, these conductive materials can be used alone or in an appropriate combination of two or more. Among them, nickel is particularly suitable because it is inexpensive compared to other metals and exhibits high reaction activity (the reactivity with fuel gas is sufficiently large). Also, the fuel electrode 20 may contain a ceramic material having ion conductivity (for example, YSZ, etc.). In this case, the mixing ratio (mass ratio) of the conductive material and the ceramic material is preferably within the range of 3:7 to 7:3, for example, about 6:4. Note that the film thickness of the fuel electrode 20 is not particularly limited and may be 5 μm or more and 100 μm or less.

[0028] (3) Solid electrolyte layer The solid electrolyte layer 30 is formed on the upper surface of the fuel electrode 20. This solid electrolyte layer 30 is a dense layer containing a solid electrolyte having oxygen ion conductivity. Regarding this solid electrolyte as well, a conventionally known material that can be used for this type of electrochemical cell can be used without particular limitation. For example, as an example of the solid electrolyte, stabilized zirconia such as yttria-stabilized zirconia (YSZ), calcia-stabilized zirconia (CSZ), scandia-stabilized zirconia (ScSZ), etc. can be mentioned. The film thickness of the solid electrolyte layer 30 is not particularly limited and may be 3 μm or more and 30 μm or less. Also, the relative density of the solid electrolyte layer 30 is, for example, about 95 to 100 (%).

[0029] (4) Air electrode (cathode) The air electrode (cathode) 40 is formed on the upper surface of the solid electrolyte layer 30. For this air electrode 40 as well, conventionally known materials that can be used in this type of electrochemical cell can be used without particular limitation. As an example of the material for such an air electrode 40, perovskite-type oxides containing La, Sr, and Co such as lanthanum strontium cobalt composite oxide (LSC, e.g., La 0.6 Sr 0.4 CoO3) and lanthanum strontium cobalt iron composite oxide (LSCF, e.g., La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3) can be mentioned. These LSC and LSCF can have various substitution ratios at both A and B sites, and those with an appropriate substitution ratio can be used according to the desired ion conductivity, reduction expansion rate, etc. Further, the air electrode 40 is preferably a porous body having a plurality of pores. Thereby, an oxygen-containing gas (air) can be supplied to the entire area of the air electrode 40. Note that the film thickness of the air electrode 40 is not particularly limited either and may be 5 μm or more and 100 μm or less.

[0030] (5) Pore structure of the support When the electrochemical cell 100 with the above configuration is used as an SOFC, an oxygen-containing gas (such as air) is supplied to the air electrode 40, and a fuel gas (such as hydrogen gas) is supplied to the fuel electrode 20. At this time, the oxygen ions generated at the air electrode 40 pass through the solid electrolyte layer 30 and reach the fuel electrode 20. Then, water and electrical energy are generated by the reaction of oxygen ions and the fuel gas at the fuel electrode 20. Here, in the electrochemical cell 100 having the support 10 as in this embodiment, since the fuel gas is supplied to the lower side of the support 10, in order to improve the operating efficiency (power generation efficiency) as an SOFC, it is required that the support 10 has suitable gas permeability. On the other hand, the support 10 in this embodiment has a pore structure that can improve gas permeability without significantly reducing the mechanical strength. Hereinafter, the pore structure of the support 10 in this embodiment will be described.

[0031] First, the support 10 in the present embodiment is provided with a plurality of first holes 12 extending from the bottom surface 10a to the top surface 10b of the support 10. As a result, sufficient circulation of the fuel gas in the film thickness direction of the support 10 can be ensured. In this support 10, each of the plurality of first holes 12 is separated by a partition wall 14, and a plurality of second holes 16 are formed inside the partition wall 14. As a result, the fuel gas flowing in the film thickness direction of the support 10 through the first holes 12 can be diffused in the plane direction of the support 10. As described above, according to the present embodiment, the fuel gas supplied to the lower side of the support 10 can be efficiently supplied to the fuel electrode 20, so the power generation efficiency of the SOFC can be improved. And the support 10 having these two types of ventilation holes can exhibit high gas permeability without significantly increasing the open porosity, so a decrease in mechanical strength can be suppressed. That is, according to the present embodiment, the trade-off relationship in the support is broken, and mechanical strength and gas permeability can be compatible at a high level. Hereinafter, the specific forms of each hole will be described.

[0032] (a) First hole As described above, the first hole 12 is a hole extending from the bottom surface 10a to the top surface 10b of the support 10. Although it will be described in detail later, this first hole 12 is formed by pressing an opening jig J having a plurality of protrusions J1 against the support (the green sheet 100 for the support) before the firing process (see FIG. 3). As shown in FIGS. 1 and 2, the first hole 12 in the present embodiment is a non-through hole that does not reach the top surface 10b of the support 10. As a result, the top surface 10b of the support 10 can be maintained flat, so that a laminated structure (typically the fuel electrode 20) can be easily formed on the top surface 10b of the support 10. Also, when the first hole 12 is a non-through hole as in the present embodiment, the permeation distance of the gas passing through the first hole 12 is set to an appropriate length, and gas diffusion by the second hole 16 is performed more efficiently, so the power generation efficiency of the SOFC can be further improved.

[0033] Incidentally, the length L1 (see Fig. 2) of the non-penetrating first hole 12 in the film thickness direction of the support 10 is preferably 10% or more, more preferably 20% or more, still more preferably 30% or more, and particularly preferably 40% or more of the film thickness T of the support 10. By this, the flow rate of the fuel gas in the film thickness direction can be increased, and the gas permeability of the support 10 can be further improved. On the other hand, the upper limit of the length L1 of the non-penetrating first hole 12 is not particularly limited, and it may be 99% or less of the film thickness T of the support 10. However, from the viewpoint of more appropriately preventing unevenness from being formed on the upper surface 10b of the support 10, the upper limit of the length of the non-penetrating first hole 12 is preferably 95% or less, more preferably 80% or less, still more preferably 85% or less, and particularly preferably 80% or less. Incidentally, the "length of the first hole in the film thickness direction" in this specification is the average value of the depths of a plurality (for example, 100) of first holes measured by microscopic observation.

[0034] Further, the non-penetrating first hole 12 preferably has a tapered shape in which the cross-sectional area decreases toward the upper surface 10b of the support 10. Although it will be described in detail later, by forming such a tapered first hole 12, it is possible to prevent a convex portion from being formed on the upper surface 10b of the support 10, and the flatness of the upper surface 10b of the support 10 can be suitably maintained. As a result, a laminated structure (typically the fuel electrode 20) can be easily formed on the upper surface 10b of the support 10. Further, as shown in Fig. 2, the planar shape of the first hole 12 of the support 10 in the present embodiment at the bottom surface 10a of the support 10 is substantially circular. In other words, a substantially conical first hole 12 is formed in the support 10 in the present embodiment. By forming such a substantially conical first hole 12, it is possible to prevent the support 10 (partition wall 14) from being damaged starting from the ridge line of the first hole 12.

[0035] Further, the average opening length (average value of the opening length L2) of the first holes 12 on the bottom surface 10a of the support 10 is preferably 20 μm or more, more preferably 30 μm or more, still more preferably 40 μm or more, and particularly preferably 50 μm or more. As the opening length L2 of the first holes 12 increases, the gas permeability of the support 10 tends to improve. On the other hand, as the opening length L2 of the first holes 12 decreases, the mechanical strength of the support 10 tends to improve. From such a viewpoint, the upper limit value of the average opening length of the first holes 12 is preferably 300 μm or less, more preferably 250 μm or less, and particularly preferably 200 μm or less. In the present specification, the "opening length" is the maximum length of the opening of the first hole on the bottom surface of the support. That is, when the conical first holes 12 as shown in FIG. 2 are formed, the diameter of the bottom surface of the first holes 12 is the "opening length L2 of the first holes". Although details will be described later, in the technology disclosed herein, the first holes 12 having a substantially quadrangular pyramid shape as shown in FIG. 5 may be formed. When such substantially quadrangular pyramid-shaped first holes 12 are formed, the length of the diagonal of the bottom surface of the first holes 12 is the "opening length L2 of the first holes". Further, when calculating the "average opening length", the opening lengths of a plurality (for example, 100) of the first holes may be measured and the average value thereof may be calculated.

[0036] In addition, the formation density of the first holes 12 on the bottom surface 10a of the support 10 is preferably 100 holes / cm 2 or more, more preferably 500 holes / cm 2 or more, still more preferably 2000 holes / cm 2 or more, and particularly preferably 4000 holes / cm 2 or more. As the formation density of the first holes 12 increases, the gas permeability of the support 10 tends to improve. On the other hand, as the formation density of the first holes 12 decreases, the mechanical strength of the support 10 tends to improve. From such a viewpoint, the formation density of the first holes 12 is preferably 10000 holes / cm 2 or less, more preferably 8000 holes / cm 2 or less, still more preferably 6000 holes / cm 2 or less, and particularly preferably 5000 holes / cm 2 or less.

[0037] Also, the average value of the formation pitch P1 of the first holes 12 in the support 10 after firing is preferably 80 μm or more, more preferably 88 μm or more, still more preferably 104 μm or more, and particularly preferably 120 μm or more. Thereby, since the interval between adjacent first holes 12 can be sufficiently widened, the mechanical strength of the support 10 can be sufficiently ensured. On the other hand, the upper limit of the average value of the formation pitch of the first holes 12 is preferably 960 μm or less, more preferably 800 μm or less, still more preferably 400 μm or less, and particularly preferably 240 μm or less. Thereby, the gas permeability of the support 10 can be suitably improved.

[0038] (b) Second holes Next, the second holes 16 are holes formed inside the partition walls 14 that separate the first holes 12. Although it will be described in detail later, these second holes 16 are formed by mixing a pore-forming material 116 in the green sheet 110 for the support and burning out the pore-forming material 116 by a firing process (see FIG. 3). Therefore, the second holes 16 have a shape corresponding to the mixed pore-forming material. For example, the second holes 16 can take a shape such as substantially spherical, flaky, needle-shaped, or amorphous. For the sake of convenience of explanation, although not shown in FIGS. 1 and 2, the partition walls 14 of the support 10 have fine pores formed in the gaps of the inorganic material in addition to the second holes 16. And the first holes 12 and the second holes 16 communicate with each other directly or through fine pores. Thereby, the fuel gas passing through the first holes 12 is diffused by the second holes 16.

[0039] Incidentally, the average pore diameter of the second holes 16 is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, and particularly preferably 5 μm or more. As the average pore diameter of the second holes 16 increases, the gas permeability of the support 10 tends to improve. On the other hand, as the average pore diameter of the second holes 16 decreases, the mechanical strength of the support 10 tends to improve. From such a viewpoint, the upper limit of the average pore diameter of the second holes 16 is preferably 60 μm or less, more preferably 40 μm or less, still more preferably 20 μm or less, and particularly preferably 10 μm or less. The "average pore diameter of the second holes" in this specification is the average value of the equivalent circle diameters of a plurality (for example, 100) of the second holes confirmed by electron microscope observation. Incidentally, the pore diameter of the second holes 16 formed in the partition walls 14 of the support 10 may vary depending on whether the electrochemical cell 100 is in an oxidized state or a reduced state. The "average pore diameter of the second holes" in this specification is calculated based on the pore diameter of the second holes when the electrochemical cell is in an oxidized state, unless otherwise specified.

[0040] Also, from the viewpoint of sufficiently ensuring the mechanical strength of the support 10, the open porosity of the partition walls 14 is preferably less than 35%, more preferably 34% or less, still more preferably 32% or less, and particularly preferably 30% or less. On the other hand, the lower limit value of the open porosity of the partition walls 14 is not particularly limited as long as it is not 0% (that is, the partition walls 14 are dense layers). However, from the viewpoint of further improving the gas permeability of the support 10, the open porosity of the partition walls 14 is preferably 5% or more, more preferably 10% or more, still more preferably 15% or more, and particularly preferably 20% or more. The "open porosity of the partition walls" is measured based on the pore diameter distribution of the partition walls using the mercury intrusion method. Specifically, a test piece obtained by cutting out a partition wall (that is, a region where the first holes are not formed) from the support is prepared, and the pore diameter distribution of the partition wall can be obtained by performing the mercury intrusion method on the test piece. Also, the "open porosity of the partition walls" in this specification is measured when the electrochemical cell is in an oxidized state, similar to the "average pore diameter of the second holes" described above.

[0041] The above describes one embodiment of the electrochemical cell disclosed herein. Note that this electrochemical cell 100 can be used not only as an SOFC but also as an SOEC. When this electrochemical cell 100 is used as an SOEC, an electric current is applied while supplying water vapor (H2O) to the lower side of the support 10. As a result, when the water vapor passes through the support 10 and is supplied to the fuel electrode (anode) 20, the water vapor is decomposed, oxygen gas is generated at the air electrode (cathode) 40, and hydrogen gas is generated at the fuel electrode (anode) 20. Then, this hydrogen gas passes through the support 10 and is recovered. At this time, since the support 10 of the electrochemical cell 100 according to this embodiment has suitable gas permeability, the supply of water vapor and the recovery of hydrogen gas when used as an SOEC can be efficiently performed.

[0042] Also, in the above-described embodiment, the laminated structure that exhibits an electrochemical reaction includes a fuel electrode (anode) 20, a solid electrolyte layer 30, and an air electrode (cathode) 40. However, the laminated structure in the technology disclosed herein is not limited to the above-described configuration as long as it exhibits an electrochemical reaction. For example, a laminated structure in which a reaction suppression layer is interposed between the solid electrolyte layer and the cathode can be constructed.

[0043] 2. Method for manufacturing an electrochemical cell Next, a method for manufacturing the electrochemical cell 100 according to this embodiment will be described. The manufacturing method according to this embodiment includes a raw material preparation step, a green sheet preparation step for the support, an opening treatment step, a lamination step, and a firing step. Hereinafter, each step will be described.

[0044] (1) Raw material preparation step In this step, raw materials for the support 10 and raw materials for each layer (for example, the fuel electrode 20, the solid electrolyte layer 30, the air electrode 40) that constitute the laminated structure are prepared. Hereinafter, the raw material for the support 10 (raw material for the support) will be specifically described. Note that raw materials for each layer other than the support 10 can be used without particular limitation as conventionally known raw materials, and since they do not have a significant impact on the effects of the technology disclosed herein, detailed description thereof will be omitted.

[0045] The raw material for the support used in the manufacturing method according to this embodiment contains at least an inorganic material, a binder, and a pore-forming material. The inorganic material is the main component constituting the support 10 after firing. The specific type of this inorganic material is as described above. The content of the inorganic material in the raw material for the support is preferably 50 wt% or more, more preferably 60 wt% or more, still more preferably 65 wt% or more, and particularly preferably 70 wt% or more. Thereby, the support 10 having a certain level of mechanical strength can be easily formed. On the other hand, considering the formability of the green sheet and the gas permeability of the support 10 after firing, the content of the inorganic material in the raw material for the support is preferably 90 wt% or less, more preferably 85 wt% or less, still more preferably 82 wt% or less, and particularly preferably 80 wt% or less. In addition, the "content in the raw material for the support" in the following description is the weight ratio (wt%) when the total amount of the raw material for the support is 100 wt% unless otherwise specified.

[0046] The binder is a resin material that imparts a certain formability to the raw material for the support. Also, when the binder burns out in the firing process, minute pores that connect the first pores 12 and the second pores 16 to each other are formed in the partition wall 14. As an example of such a binder, cellulose-based polymer compounds such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, carboxyethyl methyl cellulose, cellulose acetate phthalate; ester-based polymer compounds such as methacrylic acid esters; acrylic-based polymer compounds such as polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl methacrylate; imide-based polymer compounds such as polyamideimide, polyimide; ethylene-based polymer compounds such as polyethylene oxide; nitrile-based polymer compounds such as polyacrylonitrile, polymethacrylonitrile; urethane-based polymer compounds such as polyurethane; vinyl-based polymer compounds such as polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyvinyl fluoride, vinyl acetate; latex-based polymer compounds such as styrene-butadiene rubber; epoxy-based polymer compounds such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, glycidylamine type epoxy resin; etc. can be used. Note that the content of the binder in the raw material for the support is preferably 1 wt% or more, more preferably 5 wt% or more, still more preferably 10 wt% or more, and particularly preferably 15 wt% or more. Thereby, the green sheet for the support can be easily formed, and suitable gas permeability can be imparted to the support 10 after firing. On the other hand, considering the mechanical strength of the support 10 after firing, the upper limit of the content of the binder is preferably 35 wt% or less, more preferably 30 wt% or less, still more preferably 25 wt% or less, and particularly preferably 20 wt% or less.

[0047] The pore-forming material is a solid resin material that burns out during the firing process to form the second pores 16. As an example of such a pore-forming material, resin beads mainly composed of acrylic resin, polyester resin, polyurethane resin, epoxy resin, phenol resin, silicone resin, etc. can be mentioned. Note that the shape of the pore-forming material is not particularly limited, and it may be substantially spherical, flaky (flake-shaped), needle-shaped, amorphous, etc. Considering the mechanical strength of the support 10 after firing, it is preferable to use substantially spherical pore-forming materials. Here, "substantially spherical" in this specification refers to a form that can be generally regarded as a sphere (ball-shaped) as a whole, and refers to particles with an average aspect ratio generally in the range of 1 to 2, for example, 1 to 1.5. Note that the "aspect ratio" refers to the ratio (b / a) of the length of the long side (b) to the length of the short side (a) when a rectangle circumscribing the obtained observation image is drawn by observing the pore-forming material with an electron microscope. And the average aspect ratio means the arithmetic mean value of the aspect ratios of a plurality of particles (for example, 100 particles).

[0048] From the viewpoint of imparting suitable gas permeability to the support 10 after firing, the average particle size of the pore-forming material is preferably 1 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and particularly preferably 5 μm or more. On the other hand, considering the mechanical strength of the support 10, the average particle size of the pore-forming material is preferably 75 μm or less, more preferably 50 μm or less, still more preferably 25 μm or less, and particularly preferably 12 μm or less. Note that the "average particle size of the pore-forming material" in this specification is the average value of the particle sizes of a plurality of (for example, 100) pore-forming materials based on electron microscope observation.

[0049] Also, the content of the pore-forming material in the raw material for the support is preferably 5 wt% or more, more preferably 5.5 wt% or more, still more preferably 6 wt% or more, and particularly preferably 6.5 wt% or more. Thereby, suitable gas permeability can be imparted to the support 10 after firing. On the other hand, considering the mechanical strength of the support 10 after firing, the content of the pore-forming material in the raw material for the support is preferably 13 wt% or less, more preferably 12.5 wt% or less, still more preferably 12 wt% or less, and particularly preferably 11.5 wt% or less.

[0050] (2) Process for manufacturing the support using a green sheet In this process, a raw material for the support is formed into a sheet shape to produce a green sheet for the support. The means for producing the green sheet is not particularly limited, and conventionally known means can be adopted without particular limitation. As an example of the means for producing the green sheet for the support using the above-described raw material for the support, the roll compaction method can be mentioned. Specifically, first, a slurry in which the raw material for the support is dispersed in a predetermined dispersion medium (for example, water) is prepared. Then, the slurry is spray-dried using the spray-drying method to obtain a granulated powder of the raw material for the support. And the granulated powder of the raw material for the support is supplied between a pair of rotating rolls. Thereby, the green sheet 110 for the support containing the pore-forming material 116 (see FIG. 3) is roll-formed. Note that the means for producing the green sheet for the support is not limited to the roll compaction method, and the doctor blade method, the extrusion molding method, etc. can also be adopted.

[0051] (3) Opening treatment process Next, in the manufacturing method according to the present embodiment, an opening treatment process for forming a first hole in the green sheet for the support is performed. An example of such an opening treatment process is shown in FIG. 3. As shown in FIG. 3, in this process, with the bottom surface 110a of the green sheet 110 for the support (that is, the surface disposed downward when constructing the electrochemical cell) facing upward, the green sheet 110 for the support is placed on a pedestal B (such as a rubber sheet). And an opening jig J having a plurality of protrusions J1 is pressed against the bottom surface 110a of the green sheet 110 for the support. Thereby, the plurality of protrusions J1 are inserted into the green sheet 110 for the support, and a plurality of first holes extending from the bottom surface 110a to the upper surface 110b of the green sheet 110 for the support are formed.

[0052] Note that the shape of the protrusion J1 of the opening jig J can be appropriately changed according to the shape, dimensions, and formation density of the target first hole. For example, it is preferable that the protruding height of the protrusion J1 is smaller than the film thickness of the green sheet 110 for the support. Thereby, a non-penetrating first hole 12 as shown in FIG. 1 can be formed, and the flatness of the upper surface 10b of the support 10 can be maintained. Further, when forming a non-penetrating first hole, it is preferable to use a conical protrusion J1 as shown in FIG. 3. If the protrusion of the opening jig when forming the non-penetrating first hole is columnar, the upper surface of the green sheet for the support may be pushed down by the tip surface of the columnar protrusion, and a convex portion corresponding to the tip surface of the columnar protrusion may be formed on the upper surface of the support. On the other hand, since the conical protrusion J1 as in the present embodiment does not have a tip surface that pushes down the upper surface 110b of the green sheet 110 for the support, it is possible to prevent a convex portion from being formed on the upper surface 10b of the support 10 after production. As a result, since the flatness of the upper surface 10b of the support 10 is maintained, a laminated structure can be easily formed on the upper surface 10b of the support 10.

[0053] (4) Lamination process In this process, the green sheets of each layer including the green sheet 110 for the support are laminated. Specifically, by laminating the green sheets of each layer constituting the laminated structure on the upper surface 110b of the green sheet 110 for the support, a laminate which is a precursor of the electrochemical cell 100 is produced. Note that, for forming the green sheets of each layer (for example, the fuel electrode, the solid electrolyte layer, the air electrode) constituting the laminated structure, conventionally known means that can be used in the manufacture of the electrochemical cell can be adopted without particular limitation, and since the technology disclosed herein is not limited, detailed description thereof is omitted.

[0054] (5) Firing process In this process, co-firing for firing the fabricated laminate is performed. As a result, the green sheets of each layer are fired simultaneously, and an electrochemical cell 100 in which a laminated structure exhibiting an electrochemical reaction is supported by a support 10 is manufactured (see FIG. 1). At this time, in the present embodiment, as shown in FIG. 3, a pore-forming material 116 is included in the green sheet 110 for the support. By burning out the pore-forming material 116 in this process, a second hole 16 is formed inside the partition wall 14 of the fired support 10 (see FIG. 1). In this process, it is preferable to perform a second firing process (sintering process) for sintering an inorganic material after performing a first firing process (debinding process) for the purpose of burning out the pore-forming material 116. This can prevent the generation of cracks due to gas caused by the decomposition of a binder or the like.

[0055] In the above-described first firing process (debinding process), it is preferable to perform firing such that the firing temperature is decreased without maintaining the target temperature after raising the temperature until the target temperature is reached. Thereby, the pore-forming material 116 can be efficiently burned out. The target temperature (maximum firing temperature) in this first firing process is preferably about 200°C to 500°C (for example, 400°C). Also, the total firing time (time from the start of temperature rise to the end of heating) in the first firing process is preferably about 20 hours to 60 hours. On the other hand, in the second firing process (sintering process), it is preferable to perform firing such that the target temperature is maintained for a certain period of time after raising the temperature until the target temperature is reached. At this time, the target temperature (maximum firing temperature) in the second firing process is preferably about 1000°C to 1500°C (for example, 1300°C). Also, the firing time (time for maintaining the target temperature) in the second firing process is preferably about 2 hours to 10 hours.

[0056] The electrochemical cell 100 according to this embodiment can be manufactured by the above steps. In the above manufacturing method, so-called co-firing is performed in which the green sheet of the support 10 and the green sheets of the respective layers constituting the laminated structure are fired simultaneously. However, the manufacturing method disclosed herein is not limited to the manufacturing method that performs co-firing. For example, after manufacturing the support by firing the produced green sheet for the support alone, a laminated structure may be formed on the upper surface of the support. Even when such a manufacturing method is adopted, the electrochemical cell can be appropriately manufactured.

[0057] [Other Embodiments] As described above, one embodiment of the technology disclosed herein has been described. Note that the technology disclosed herein is not limited to the first embodiment described above, and can include various embodiments. Hereinafter, other embodiments of the technology disclosed herein will be described. FIG. 4 is a diagram schematically showing an electrochemical cell according to the second embodiment. Further, FIG. 5 is a partial cross-sectional perspective view showing a support of an electrochemical cell according to the third embodiment.

[0058] 1. Second Embodiment In the first embodiment, the first hole 12 that is conical and non-penetrating is formed in the support 10 (see FIG. 1). However, the first hole only needs to be formed so as to extend from the lower surface to the upper surface of the support, and is not limited to the shape of the first embodiment. For example, as shown in FIG. 4, the support 10 in the second embodiment is formed with a first hole 12 that is columnar and penetrates the support 10. Even when such a columnar through-hole is formed as the first hole 12, since the fuel gas can be efficiently supplied in the film thickness direction of the support 10, it is possible to contribute to the improvement of gas permeability while suppressing a significant decrease in the mechanical strength of the support 10. However, when this type of through-hole is formed in the support 10, it becomes difficult to form a laminated structure on the upper surface 10b of the support 10, which may cause a decrease in production efficiency. From such a viewpoint, the non-through-hole as shown in FIG. 1 is preferable for the first hole 12.

[0059] When forming the first hole 12 as shown in FIG. 4, it is preferable to perform punching on the green sheet for the support before firing. By doing so, a columnar first hole 12 penetrating the support 10 can be easily formed. Further, when forming a through hole as the first hole, it is preferable to interpose an intermediate layer made of a raw material for the support between the support and the laminated structure. This can flatten the surface for forming the laminated structure and facilitate the formation of the laminated structure. However, considering the addition of working steps and the increase in the amount of raw material used due to the formation of the intermediate layer, it is more preferable to form a conical non-through hole as the first hole 12 as in the first embodiment to maintain the flatness of the upper surface 10a of the support 10.

[0060] 2. Third Embodiment Further, in the first embodiment, a first hole 12 (typically, a conical first hole) having a circular planar shape is formed in the bottom surface 10a of the support 10 (see FIG. 2). However, the shape of the first hole in plan view is not particularly limited, and various shapes can be adopted. Another example of the planar shape of such a first hole is a rectangular shape. For example, as shown in FIG. 5, even when a first hole 12 having a quadrangular shape (typically, a quadrangular pyramid shape) is formed in plan view, it is possible to improve gas permeability while suppressing a significant decrease in the mechanical strength of the support 10. However, considering the possibility of the partition wall 14 being damaged starting from the ridge line of the quadrangular pyramid-shaped first hole 12, it is more preferable to form a substantially conical first hole 12 as in the first embodiment.

[0061] [Test Example] Hereinafter, test examples related to the technology disclosed herein will be described. Note that the following description is not intended to limit the technology disclosed herein to the content shown in the test examples.

[0062] A. First Test In this test, eight types of supports (Samples 1 to 8) with different compositions were prepared, and various performances of each support were evaluated.

[0063] 1. Preparation of Samples (1) Sample 1 First, an inorganic material was prepared by mixing YSZ with an average particle size of 0.3 μm and nickel oxide with an average particle size of 0.5 μm at a ratio of 1:1. Then, this inorganic material, a pore-forming material (resin beads) with an average particle size of 5 μm, and a resin binder (acrylic binder) were mixed to prepare a raw material for the support. The content of the inorganic material in this raw material for the support was 72 wt%, the content of the pore-forming material was 10 wt%, and the content of the resin binder was 18 wt%. Then, this raw material for the support was kneaded with a dispersion medium (water) using a pot mill for 8 hours to obtain a raw material slurry. Next, this raw material slurry was spray-dried to produce a granulated powder with an average particle diameter of 30 μm. Then, a green sheet for the support with a film thickness of 360 μm was produced by roll compaction of the granulated powder.

[0064] And in Sample 1, the prepared green sheet for the support was placed on a rubber sheet, and an opening jig with a plurality of quadrangular pyramid-shaped protrusions was pressed at a pressure of 50 kg / cm 2 to form a plurality of substantially quadrangular pyramid-shaped first holes in the green sheet for the support. The height of the protrusions in Sample 1 was set to 56% of the film thickness of the green sheet for the support. Also, the pitch of the protrusions forming the first holes was set to 1200 μm. Next, a first firing treatment (debinding treatment) with a firing temperature set to 400 °C and a second firing treatment (sintering treatment) with a firing temperature set to 1300 °C were sequentially performed to produce a support for the electrochemical cell. The total firing time of the first firing treatment was 24 hours, and the total firing time of the second firing treatment was 40 hours. And the support after such firing had shrunk to about 80% compared to the green sheet for the support before firing. That is, in the support after firing, the film thickness was about 300 μm, and the formation pitch of the first holes was 960 μm.

[0065] (2) Samples 2 - 5 Supports were produced under the same conditions as in Sample 1, except that the form of the protrusions (shape, height of the protrusions relative to the film thickness, formation pitch) of the opening jig was changed. The shape, protruding height, and formation pitch of the protrusions in each sample are shown in Table 1 described later.

[0066] (3) Samples 6 - 8 The support was fabricated in the same procedure as Sample 1, except that the formation of the first hole using the opening jig was not performed. In Samples 6 - 8, the content of the pore - forming material in the support raw material was varied. Specifically, in Sample 6, the content of the pore - forming material was set to 10 wt%, the same as in Samples 1 - 5. In Sample 7, the content of the pore - forming material was increased to 14 wt%, and in Sample 8, the content of the pore - forming material was increased to 18 wt%.

[0067] 2. Evaluation Test (1) Microscopic Observation The support of each sample after firing was observed with an optical microscope. The photograph of the bottom surface of the support of Sample 3 (magnification: 160 times) is shown in Fig. 7, and the cross - sectional photograph (magnification: 160 times) is shown in Fig. 8. Also, the photograph of the bottom surface of the support of Sample 4 (magnification: 160 times) is shown in Fig. 9, and the cross - sectional photograph (magnification: 160 times) is shown in Fig. 10.

[0068] (2) Open - Pore Ratio In this evaluation, the open - pore ratio of the partition walls of the support after firing was measured. Specifically, from the support of each sample, regions (partition walls) where the first hole was not formed were cut out to obtain five test pieces with an area of 5 mm×10 mm. Then, the mercury intrusion method was performed on each test piece, and after obtaining the pore size distribution of the partition walls of each sample, the average value of the open - pore ratio was calculated. The results are shown in Table 1.

[0069] (2) Gas Permeability Test gas (nitrogen) was supplied to the supports of Samples 1 - 8 to evaluate the gas permeability. Specifically, in accordance with JIS R 1761, the gas permeability rate (mol·m / m 2 ·s·Pa) of each sample was measured. Then, based on this measurement result, the gas permeability of each sample was evaluated in three levels of "○, △, ×". Specifically, samples with a gas permeability rate less than 1.3×10 -9 were evaluated as "×", samples with a gas permeability rate of 1.3×10 -9 or more and less than 2.7×10 -9 were evaluated as "△", and samples with a gas permeability rate of 2.7×10 -9The above samples were evaluated as "○". The evaluation results are shown in Table 1.

[0070] (3) Mechanical strength For the supports of Samples 1 to 8, the three-point bending strength (MPa) was measured based on the bending strength test method according to JIS R 1601:2008. In this test, a circular pin (diameter: 4.0 mm) was used for the jig to fix the support, and the distance between the fulcrums was set to 30 mm. Also, the pressurization rate during the test was set to 0.5 mm / min. The measurement results are shown in Table 1.

[0071] (4) Conductivity In this test, first, the supports of Samples 1 to 8 were subjected to a reduction treatment by exposing them to a reducing gas (96% nitrogen, 4% hydrogen). Then, the conductivity of the supports of Samples 1 to 8 after reduction was measured based on the four-terminal method. In this test, the measurement temperature was set to 700°C. Samples with a conductivity of less than 1300 S / cm were evaluated as "×", samples with a conductivity of 1300 S / cm or more and less than 1500 S / cm were evaluated as "△", and samples with a conductivity of 1500 S / cm or more were evaluated as "○". The evaluation results are shown in Table 1.

[0072]

Table 1

[0073] First, as shown in FIGS. 6 to 9, in Samples 1 to 5, the first holes having a shape corresponding to the protrusions of the opening jig were formed. And as shown in Table 1, in these Samples 1 to 5, the mechanical strength and gas permeability were compatible at a high level without increasing the open porosity of the partition wall. On the other hand, in Samples 6 to 8, it was confirmed that there was a trade-off relationship in which the gas permeability improved while the mechanical strength significantly decreased when the content of the pore-forming material was increased to increase the open porosity. From the above results, it was found that a support in which the mechanical strength and gas permeability were compatible at a high level could be produced by forming two types of holes, the first holes extending in the film thickness direction and the second holes derived from the pore-forming material.

[0074] B. Second Test In this test, an electrochemical cell was constructed using the support of Sample 4, which had suitable mechanical strength and gas permeability in the above first test. Specifically, a raw material for the fuel electrode was prepared by kneading nickel oxide, YSZ, and a binder (methyl cellulose) at a mass ratio of 5:3:2. Then, this raw material for the fuel electrode was applied and dried on the upper surface of the support of Sample 4 using the screen printing method to form a green sheet for the fuel electrode with a film thickness of 10 μm.

[0075] Next, a raw material for the solid electrolyte layer was prepared by kneading YSZ and a binder (ethyl cellulose) at a mass ratio of 7:3. This was applied and dried on the upper surface of the green sheet for the fuel electrode using the screen printing method to form a green sheet having a solid electrolyte layer with a film thickness of 6 μm. Then, by firing at 1300°C for 7 hours, a fuel electrode and a solid electrolyte layer were formed on the support. Next, a raw material for the air electrode was prepared by kneading LSCF composite oxide (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O3) and a binder (ethyl cellulose) at a mass ratio of 7:3. This was applied and dried on the upper surface of the solid electrolyte layer using the screen printing method to form a green sheet for the air electrode with a film thickness of 40 μm. Then, by firing at 1100°C for 1 hour, an air electrode was formed on the upper surface of the solid electrolyte layer. As a result of supplying hydrogen gas to the lower side of the support of this cell structure and supplying air to the air electrode, it was found that an electrochemical cell that functions properly as an SOFC can be constructed even when using a support having the first holes and the second holes like Sample 4.

[0076] As described above, specific examples of the present invention have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

Explanation of Reference Numerals

[0077] 10 Support 12 First Hole 14 partition wall 16 second hole 100 electrochemical cell 110 green sheet for support 116 pore former

Claims

1. An electrochemical cell comprising a plate-shaped support for supporting a laminated structure exhibiting an electrochemical reaction, wherein the support includes a plurality of first holes extending from the bottom surface to the top surface of the support, partition walls separating each of the plurality of first holes, and a plurality of second holes formed inside the partition walls, and the first holes are non-through holes that do not reach the top surface of the support and have a conical shape with a decreasing cross-sectional area toward the top surface of the support, and the support is an electrochemical cell containing a ceramic material.

2. The electrochemical cell according to claim 1, wherein the length of the first holes in the thickness direction of the support is 10% or more and 95% or less of the thickness of the support.

3. The electrochemical cell according to claim 1 or 2, wherein the average opening length of the first holes on the bottom surface of the support is 20 μm or more and 300 μm or less.

4. The electrochemical cell according to any one of claims 1 to 3, wherein the formation density of the first holes on the bottom surface of the support is 100 holes / cm ２ or more and 10,000 holes / cm ２ or less.

5. The electrochemical cell according to any one of claims 1 to 4, wherein the average value of the formation pitch of the first holes is 80 μm or more and 960 μm or less.

6. The electrochemical cell according to any one of claims 1 to 5, wherein the open porosity of the partition walls in the oxidized state is 30% or less.

7. The electrochemical cell according to any one of claims 1 to 6, wherein the laminated structure includes an anode formed on the top surface of the support, a solid electrolyte layer formed on the top surface of the anode, and a cathode formed on the top surface of the solid electrolyte layer.

8. A method for manufacturing an electrochemical cell including a plate-like support for supporting a laminated structure that exhibits an electrochemical reaction, the method comprising: preparing a raw material for the support including at least an inorganic material containing a ceramic material, a binder, and a pore former; forming the raw material for the support into a sheet shape to produce a green sheet for the support; forming a plurality of first holes extending from the bottom surface to the top surface of the green sheet for the support by pressing an opening jig having a plurality of protrusions against the bottom surface of the green sheet for the support; firing the green sheet for the support to burn out the pore former and forming second holes inside partition walls separating each of the plurality of first holes; and the method for manufacturing an electrochemical cell, wherein the plurality of protrusions formed on the opening jig have a conical shape, and a protruding height of the plurality of protrusions is smaller than a film thickness of the green sheet for the support.

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