Solid electrolyte layer, electrochemical cell, electrochemical cell device, module, and module storage device

Abstract

To provide a solid electrolyte layer, an electrochemical cell, an electrochemical cell device, a module, and a module storage device that can improve durability.SOLUTION: A solid electrolyte layer has a plurality of electrolyte particles including oxide, and a plurality of pores. The plurality of electrolyte particles include first particles and second particles. The plurality of pores include first pores and second pores. The first pores are in contact with the first particles. The second pores are inside the second particles.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a solid electrolyte layer, an electrochemical cell, an electrochemical cell device, a module, and a module housing device.

Background Art

[0002] In recent years, various fuel cell stack devices having a plurality of fuel cells have been proposed as next-generation energy. A fuel cell is a type of electrochemical cell that can obtain electric power using a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0004] A solid electrolyte layer according to one aspect of the embodiment has a plurality of electrolyte particles containing an oxide and a plurality of pores. The plurality of electrolyte particles include a first particle and a second particle. The plurality of pores include a first pore and a second pore. The first pore is in contact with the first particle. The second pore is inside the second particle.

[0005] Also, an electrochemical cell of the present disclosure includes the solid electrolyte layer described above.

[0006] Also, an electrochemical cell device of the present disclosure has a cell stack including the electrochemical cell described above.

[0007] Also, a module of the present disclosure includes the electrochemical cell device described above and a storage container for storing the electrochemical cell device.

[0008] In addition, the module housing device of the present disclosure includes the module described above, auxiliary equipment for operating the module, and an exterior case for housing the module and the auxiliary equipment.

Brief Description of the Drawings

[0009]

Figure 1A

Figure 1B

Figure 1C

Figure 2A

Figure 2B

Figure 2C

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11A

Figure 11B

Figure 11C

Figure 12

[0010] In the above fuel cell stack device, there was room for improvement in terms of improving durability.

[0011] Therefore, there is an expectation for providing a solid electrolyte layer, an electrochemical cell, an electrochemical cell device, a module, and a module housing device that can improve durability.

[0012] Hereinafter, embodiments of the solid electrolyte layer, electrochemical cell, electrochemical cell device, module, and module housing device disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that this disclosure is not limited by the embodiments shown below.

[0013] Also, note that the drawings are schematic, and it is necessary to be aware that the dimensional relationships between elements, the ratios of the elements, etc. may be different from reality. Furthermore, there may be parts where the dimensional relationships and ratios between the drawings are different from each other.

[0014] [First Embodiment] [Configuration of Electrochemical Cell] First, with reference to FIGS. 1A to 1C, an electrochemical cell according to the first embodiment will be described using an example of a solid oxide type fuel cell. The electrochemical cell device may include a cell stack having a plurality of electrochemical cells. An electrochemical cell device having a plurality of electrochemical cells is simply referred to as a cell stack device.

[0015] FIG. 1A is a cross-sectional view showing an example of the electrochemical cell according to the first embodiment. FIG. 1B is a side view of an example of the electrochemical cell according to the first embodiment as viewed from the air electrode side. FIG. 1C is a side view of an example of the electrochemical cell according to the first embodiment as viewed from the interconnector side. Note that FIGS. 1A to 1C show a part of each component of the electrochemical cell in an enlarged manner. Hereinafter, the electrochemical cell may also be simply referred to as a cell.

[0016] In the example shown in FIGS. 1A to 1C, the cell 1 is a hollow flat plate type and is an elongated plate shape. As shown in FIG. 1B, the shape of the entire cell 1 as viewed from the side may be, for example, a rectangle having a side length in the length direction L of 5 cm to 50 cm, and a length in the width direction W orthogonal to this length direction L may be, for example, 1 cm to 10 cm. The thickness in the thickness direction T of the entire cell 1 may be, for example, 1 mm to 5 mm.

[0017] As shown in FIG. 1A, the cell 1 includes a conductive support substrate 2, an element portion 3, and an interconnector 4. The support substrate 2 is columnar and has a first flat surface n1 and a second flat surface n2 which are a pair of opposing flat surfaces, and a pair of arc-shaped side surfaces m connecting the first flat surface n1 and the second flat surface n2.

[0018] The element portion 3 is located on the first flat surface n1 of the support substrate 2. Such an element portion 3 has a fuel electrode 5 which is a first electrode, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode 8 which is a second electrode.

[0019] Further, as shown in FIG. 1B, the air electrode 8 does not extend to the lower end of the cell 1. At the lower end of the cell 1, only the solid electrolyte layer 6 is exposed on the surface of the first flat surface n1. Also, as shown in FIG. 1C, the interconnector 4 may extend to the lower end of the cell 1. At the lower end of the cell 1, the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. As shown in FIG. 1A, on the surface of the pair of arc-shaped side surfaces m of the cell 1, the solid electrolyte layer 6 is exposed. The interconnector 4 does not have to extend to the lower end of the cell 1.

[0020] Hereinafter, each member constituting the cell 1 will be described.

[0021] The support substrate 2 has a gas flow path 2a through which gas flows inside. The example of the support substrate 2 shown in FIG. 1A has six gas flow paths 2a. The support substrate 2 has gas permeability and allows the fuel gas flowing through the gas flow path 2a to permeate to the fuel electrode 5. The support substrate 2 may have conductivity. The support substrate 2 having conductivity collects the electricity generated in the element part 3 to the interconnector 4.

[0022] The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. The iron group metal component may be, for example, Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include one or more rare earth elements selected from, for example, Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0023] As the material of the fuel electrode 5, generally known materials can be used. The fuel electrode 5 may be made of, for example, a porous conductive ceramic such as ZrO2 in which calcium oxide, magnesium oxide, or a rare earth element oxide is solid-solved, and Ni and / or NiO. This rare earth element oxide may contain, for example, a plurality of rare earth elements selected from Sc, Y, La, Ce, Nd, Sm, Gd, Dy, and Yb. ZrO2 in which calcium oxide, magnesium oxide, or a rare earth element oxide is solid-solved is sometimes referred to as stabilized zirconia. Stabilized zirconia may also include partially stabilized zirconia.

[0024] The solid electrolyte layer 6 is an electrolyte that transfers ions between the fuel electrode 5 and the air electrode 8. At the same time, the solid electrolyte layer 6 has gas barrier properties and makes it difficult for fuel gas and oxygen-containing gas to leak.

[0025] The material of the solid electrolyte layer 6 may be, for example, ZrO2 in which 3 mol% to 15 mol% of a rare earth element oxide is solid-solved. The rare earth element oxide may contain, for example, one or more rare earth elements selected from Sc, Y, La, Ce, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may contain, for example, ZrO2 in which Yb, Sc, or Gd is solid-solved, or may contain BaZrO3 in which Sc, Y, or Yb is solid-solved. Details of the solid electrolyte layer 6 will be described later.

[0026] The intermediate layer 7 functions as a diffusion suppression layer. The intermediate layer 7 makes it difficult for elements such as Sr (strontium) contained in the air electrode 8 described later to diffuse into the solid electrolyte layer 6, thereby making it difficult to form an electric resistance layer such as SrZrO3 in the solid electrolyte layer 6.

[0027] The material of the intermediate layer 7 is not particularly limited as long as it generally makes it difficult for elements to diffuse between the air electrode 8 and the solid electrolyte layer 6. The material of the intermediate layer 7 may contain, for example, cerium oxide (CeO2) in which rare earth elements excluding Ce (cerium) are solid-dissolved. As such rare earth elements, Gd (gadolinium), Sm (samarium), etc. may be used.

[0028] The air electrode 8 has gas permeability. The open porosity of the air electrode 8 may be, for example, 20% or more, particularly in the range of 30% to 50%.

[0029] The material of the air electrode 8 is not particularly limited as long as it is generally used for air electrodes. The material of the air electrode 8 may be, for example, a conductive ceramic such as a so-called ABO3-type perovskite oxide.

[0030] The material of the air electrode 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. Examples of such composite oxides include La x Sr 1-x Co y Fe 1-y O3, La x Sr 1-x MnO3, La x Sr 1-x FeO3, La x Sr 1-x CoO3, etc. Here, x is 0 < x < 1 and y is 0 < y < 1.

[0031] Further, the interconnector 4 is dense and makes it difficult for fuel gas flowing through the gas flow path 2a located inside the support substrate 2 and oxygen-containing gas flowing outside the support substrate 2 to leak. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0032] As the material of the interconnector 4, a lanthanum chromite-based perovskite oxide (LaCrO3-based oxide), a lanthanum strontium titanium-based perovskite oxide (LaSrTiO3-based oxide), or the like may be used. These materials have conductivity and are less likely to be reduced or oxidized even when they come into contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

[0033] <Configuration of the Electrochemical Cell Device> Next, the electrochemical cell device according to the present embodiment using the cell 1 described above will be described with reference to FIGS. 2A to 2C. FIG. 2A is a perspective view showing an example of the electrochemical cell device according to the first embodiment. FIG. 2B is a cross-sectional view taken along the line X-X shown in FIG. 2A. FIG. 2C is a top view showing an example of the electrochemical cell device according to the first embodiment.

[0034] As shown in FIG. 2A, the cell stack device 10 includes a cell stack 11 having a plurality of cells 1 arranged (stacked) in the thickness direction T (see FIG. 1A) of the cell 1, and a fixing member 12.

[0035] The fixing member 12 has a fixing material 13 and a support member 14. The support member 14 supports the cell 1. The fixing material 13 fixes the cell 1 to the support member 14. Further, the support member 14 has a support body 15 and a gas tank 16. The support body 15 and the gas tank 16, which are the support members 14, are made of, for example, metal.

[0036] As shown in FIG. 2B, the support body 15 has insertion holes 15a into which the lower end portions of the plurality of cells 1 are inserted. The lower end portions of the plurality of cells 1 and the inner wall of the insertion holes 15a are joined by the fixing material 13.

[0037] The gas tank 16 has an opening for supplying a reaction gas to the plurality of cells 1 through the insertion holes 15a, and a concave groove 16a located around such an opening. The end portion of the outer periphery of the support body 15 is joined to the gas tank 16 by a bonding material 21 filled in the concave groove 16a of the gas tank 16.

[0038] In the example shown in FIG. 2A, fuel gas is stored in an internal space 22 (see FIG. 2B) formed by a support 15, which is a support member 14, and a gas tank 16. A gas circulation pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas circulation pipe 20 and is supplied from the gas tank 16 to a gas flow path 2a (see FIG. 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated by a reformer 102 (see FIG. 4), which will be described later.

[0039] A hydrogen-rich fuel gas can be generated by steam reforming or the like of a raw fuel. When generating a fuel gas by steam reforming, the fuel gas contains steam.

[0040] In the example shown in FIG. 2A, there are two rows of cell stacks 11, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 has a plurality of cells 1. Each cell stack 11 is fixed to each support 15. The gas tank 16 has two through holes on its upper surface. Each support 15 is disposed in each through hole. The internal space 22 is formed by one gas tank 16 and two supports 15.

[0041] The shape of the insertion hole 15a may be, for example, an oval shape in a top view. The insertion hole 15a may be, for example, such that the length in the arrangement direction of the cells 1, that is, the thickness direction T, is greater than the distance between two end current collecting members 17 located at both ends of the cell stack 11. The width of the insertion hole 15a may be, for example, greater than the length in the width direction W (see FIG. 1A) of the cell 1.

[0042] As shown in FIG. 2B, the joint between the inner wall of the insertion hole 15a and the lower end portion of the cell 1 is filled with a fixing material 13 and solidified. Thereby, the inner wall of the insertion hole 15a and the lower end portions of the plurality of cells 1 are joined and fixed respectively, and the lower end portions of the cells 1 are joined and fixed to each other. The gas flow path 2a of each cell 1 communicates with the internal space 22 of the support member 14 at the lower end portion.

[0043] The fixing member 13 and the joining member 21 can be made of materials with low conductivity such as glass. As specific materials for the fixing member 13 and the joining member 21, amorphous glass or the like may be used, and particularly, crystallized glass or the like may be used.

[0044] As the crystallized glass, for example, any of materials such as SiO2-CaO system, MgO-B2O3 system, La2O3-B2O3-MgO system, La2O3-B2O3-ZnO system, SiO2-CaO-ZnO system may be used, and particularly, a material of SiO2-MgO system may be used.

[0045] Also, as shown in FIG. 2B, between adjacent cells 1 among the plurality of cells 1, a connection member 18 is interposed. The connection member 18 electrically connects the fuel electrode 5 of one adjacent cell 1 and the air electrode 8 of the other cell 1 in series. More specifically, the connection member 18 connects an interconnector 4 electrically connected to the fuel electrode 5 of one adjacent cell 1 and the air electrode 8 of the other cell 1.

[0046] Also, as shown in FIG. 2B, an end current collecting member 17 is electrically connected to the cell 1 located on the outermost side in the arrangement direction of the plurality of cells 1. The end current collecting member 17 is connected to a conductive portion 19 protruding outside the cell stack 11. The conductive portion 19 collects the electricity generated by the power generation of the cell 1 and draws it out to the outside. In FIG. 2A, the illustration of the end current collecting member 17 is omitted.

[0047] Also, as shown in FIG. 2C, the cell stack device 10 may be a single battery in which two cell stacks 11A and 11B are connected in series. In such a case, the conductive portion 19 of the cell stack device 10 is distinguished into a positive electrode terminal 19A, a negative electrode terminal 19B, and a connection terminal 19C.

[0048] The positive electrode terminal 19A is the positive electrode when the cell stack 11 outputs the generated power to the outside, and is electrically connected to the end collector member 17 on the positive electrode side in the cell stack 11A. The negative electrode terminal 19B is the negative electrode when the cell stack 11 outputs the generated power to the outside, and is electrically connected to the end collector member 17 on the negative electrode side in the cell stack 11B.

[0049] The connection terminal 19C electrically connects the end collector member 17 on the negative electrode side in the cell stack 11A and the end collector member 17 on the positive electrode side in the cell stack 11B.

[0050] <Details of the solid electrolyte layer> Next, the details of the solid electrolyte layer 6 included in the electrochemical cell according to the present embodiment will be described with reference to FIG. 3. FIG. 3 is an enlarged cross-sectional view of the region R1 shown in FIG. 1A.

[0051] As shown in FIG. 3, the solid electrolyte layer 6 has a first surface 6a and a second surface 6b located at both ends in the thickness direction T. The first surface 6a is in contact with the fuel electrode 5. The second surface 6b is in contact with the intermediate layer 7.

[0052] The solid electrolyte layer 6 has a plurality of electrolyte particles 60 and a plurality of pores 62. Each of the plurality of electrolyte particles 60 contains an oxide. Among the plurality of electrolyte particles 60, adjacent electrolyte particles 60 are partitioned by grain boundaries 61. The plurality of electrolyte particles 60 include first particles and second particles.

[0053] In addition, the plurality of pores 62 include a first pore 62a and a second pore 62b. The first pore 62a is located outside the electrolyte particles 60 which are the first particles and is in contact with the first particles. The first pore 62a is a pore 62 located at the grain boundary 61 in the cross-section shown in FIG. 3, that is, the cross-section of the solid electrolyte layer 6 intersecting the first surface 6a and the second surface 6b. In other words, the first pore 62a is in contact with two or more different first particles. The first particles may be in contact with two or more first pores 62a. The second pore 62b is a pore 62 located inside the electrolyte particles 60 which are the second particles. The second pore 62b is contained inside one second particle. The second particles may contain two or more second pores 62b. The first particles in contact with the first pore 62a may also serve as the second particles containing the second pore 62b inside. Further, the plurality of electrolyte particles 60 may have electrolyte particles 60 that are not in contact with the first pore 62a and do not contain the second pore 62b inside.

[0054] By having the plurality of pores 62 including the first pore 62a and the second pore 62b, the solid electrolyte layer 6 is less likely to generate cracks, delamination, etc. associated with, for example, thermal expansion and / or thermal contraction. Thereby, the solid electrolyte layer 6 and the cell 1 having such a solid electrolyte layer 6 have improved durability as compared with, for example, the case where the plurality of pores 62 do not include the first pore 62a and the second pore 62b.

[0055] Also, in the cross-section shown in FIG. 3, the number of the first pores 62a present per unit area may be less than that of the second pores 62b. For example, the number of the first pores 62a present per unit area may be 1 / 2 or less of the number of the second pores 62b. Thereby, the solid electrolyte layer 6 and the cell 1 having such a solid electrolyte layer 6 have improved durability because the adjacent electrolyte particles 60 are less likely to delaminate at the grain boundary 61 as compared with, for example, the case where the first pores 62a are more than the second pores 62b. Further, since there is a concern that the ions are less likely to conduct between the electrolyte particles 60 due to the first pores 62a, the solid electrolyte layer 6 may have only the second pores 62b and not have the first pores 62a.

[0056] Further, in the cross-section shown in FIG. 3, when the average diameter of the first pores 62a is defined as the first diameter and the average diameter of the second pores 62b is defined as the second diameter, the first diameter may be smaller than the second diameter. Here, the average diameters of the first pores 62a and the second pores 62b can be calculated based on the equivalent circle diameters obtained by observing the cross-section of the solid electrolyte layer 6. Thereby, in the solid electrolyte layer 6 and the cell 1 having such a solid electrolyte layer 6, for example, adjacent electrolyte particles 60 are less likely to peel off at the grain boundaries 61 as compared with the case where the first diameter is larger than the second diameter, so that the durability is improved.

[0057] The first diameter, which is the average diameter of the first pores 62a, may be, for example, 0.3 μm or less, particularly 0.1 μm or more and 0.3 μm or less.

[0058] Further, the second diameter, which is the average diameter of the second pores 62b, may be, for example, 1 μm or less, particularly 0.4 μm or more and 0.7 μm or less.

[0059] Further, in the cross-section shown in FIG. 3, the area ratio of the plurality of pores 62 may be 2% or less. Thereby, for example, the movement of ions in the thickness direction T inside the solid electrolyte layer 6 is less likely to be hindered, and the ionic conductivity is improved. Further, according to the cell 1 having such a solid electrolyte layer 6, for example, the power generation performance is improved. The area ratio of the plurality of pores 62 may be 0.3% or more. Thereby, the solid electrolyte layer 6 and the cell 1 having high durability can be obtained.

[0060] Here, the average thickness t of the solid electrolyte layer 6 can be calculated using a cross-sectional photograph of the solid electrolyte layer 6. Also, the arrangement and diameter of the plurality of pores 62 in the solid electrolyte layer 6 can be confirmed and calculated by analyzing the cross-section of the solid electrolyte layer 6 that intersects the first surface 6a and the second surface 6b. Specifically, a cross-sectional photograph of the solid electrolyte layer 6 is taken with an SEM at, for example, a magnification of 5000 times. The cross-sectional photograph taken is subjected to image analysis to calculate the diameters of the first pore 62a and the second pore 62b located in a region having 200 or more electrolyte particles 60 between the first surface 6a and the second surface 6b. The diameters of the first pore 62a and the second pore 62b are, for example, those obtained by measuring the areas of the first pore 62a and the second pore 62b using image analysis software and converting the areas into equivalent circle diameters. Further, a square having the average thickness t of the solid electrolyte layer 6 as one side may be used as a unit area, and the number of the first pores 62a and the second pores 62b existing in this unit area may be counted respectively.

[0061] <Module> Next, the module according to the embodiment of the present disclosure using the above-described electrochemical cell device will be described with reference to FIG. 4. FIG. 4 is an external perspective view showing an example of the module according to the first embodiment. FIG. 4 shows a state in which a front surface and a rear surface, which are parts of the storage container 101, are removed and the cell stack device 10 of the fuel cell stored inside is taken out backward.

[0062] As shown in FIG. 4, the module 100 includes a storage container 101 and a cell stack device 10 stored in the storage container. Further, a reformer 102 is disposed above the cell stack device 10.

[0063] Such a reformer 102 reforms a raw fuel such as natural gas or kerosene to generate a fuel gas and supplies it to the cell 1. The raw fuel is supplied to the reformer 102 through the raw fuel supply pipe 103. Note that the reformer 102 may include a vaporization unit 102a that vaporizes water and a reforming unit 102b. The reforming unit 102b includes a reforming catalyst (not shown) and reforms the raw fuel into a fuel gas. Such a reformer 102 can perform steam reforming, which is an efficient reforming reaction.

[0064] Then, the fuel gas generated by the reformer 102 is supplied to the gas flow path 2a (see FIG. 1A) of the cell 1 through the gas flow pipe 20, the gas tank 16, and the support member 14.

[0065] Also, in the module 100 having the above-described configuration, the temperature inside the module 100 during normal power generation becomes about 500°C to 1000°C due to the combustion of the gas and the power generation of the cell 1.

[0066] In such a module 100, as described above, by accommodating the cell stack device 10 having the cell 1 whose performance is improved, the module 100 whose performance is improved can be obtained.

[0067] <Module housing device> FIG. 5 is an exploded perspective view schematically showing an example of a module housing device according to the first embodiment. The module housing device 110 according to the present embodiment includes an exterior case 111, the module 100 shown in FIG. 4, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed inside the exterior case 111. Note that some configurations are omitted in FIG. 5.

[0068] The exterior case 111 of the module housing device 110 shown in FIG. 5 has a support column 112 and an exterior plate 113. The partition plate 114 vertically partitions the inside of the exterior case 111. The space above the partition plate 114 inside the exterior case 111 is a module housing chamber 115 for housing the module 100, and the space below the partition plate 114 inside the exterior case 111 is an auxiliary machine housing chamber 116 for housing auxiliary machines for operating the module 100. In FIG. 5, the auxiliary machines housed in the auxiliary machine housing chamber 116 are omitted.

[0069] Also, the partition plate 114 has an air circulation port 117 for flowing the air in the auxiliary machine housing chamber 116 to the module housing chamber 115 side. The exterior plate 113 constituting the module housing chamber 115 has an exhaust port 118 for exhausting the air in the module housing chamber 115.

[0070] In such a module housing device 110, as described above, by providing the module 100 with improved performance in the module housing chamber 115, a module housing device 110 with improved performance can be obtained.

[0071] In the above-described embodiment, the case where a hollow flat plate-shaped support substrate is used is exemplified, but it can also be applied to a cell stack device using a cylindrical support substrate.

[0072] [Second Embodiment] Next, the electrochemical cell and the electrochemical cell device according to the second embodiment will be described with reference to FIGS. 6A to 7.

[0073] In the above-described embodiment, the so-called "vertical stripe type" in which only one element part including a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the surface of the support substrate is exemplified. However, the so-called "horizontal stripe type" electrochemical cell in which element parts are provided at a plurality of locations separated from each other on the surface of the support substrate and adjacent element parts are electrically connected can be applied to a horizontal stripe type electrochemical cell device in which such electrochemical cells are arranged.

[0074] FIG. 6A is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. FIG. 6B is a cross-sectional view showing an electrochemical cell according to the second embodiment. FIG. 7 is an enlarged view of a region R2 shown in FIG. 6B.

[0075] As shown in FIG. 6A, in the cell stack device 10A, a plurality of cells 1A extend in the longitudinal direction L from a pipe 22a through which fuel gas flows. Each cell 1A has a plurality of element portions 3 on a support substrate 2. Inside the support substrate 2, a gas flow path 2a through which fuel gas from the pipe 22a flows is provided.

[0076] Also, each cell 1A is electrically connected to each other via a connection member 31. The connection member 31 is located between the element portions 3 that each cell 1A has, and connects adjacent cells 1A.

[0077] Also, as shown in FIG. 6B, the cell 1A according to the second embodiment includes a support substrate 2, a pair of element portions 3, and a sealing portion 30. The support substrate 2 has a columnar shape having a first flat surface n1 and a second flat surface n2 that are a pair of opposing flat surfaces, and a pair of arc-shaped side surfaces m that connect the first flat surface n1 and the second flat surface n2.

[0078] The pair of element portions 3 are positioned on the first flat surface n1 and the second flat surface n2 of the support substrate 2 so as to face each other. Also, the sealing portion 30 is positioned so as to cover the side surface m of the support substrate 2.

[0079] In the cross-section shown in FIG. 7, the solid electrolyte layer 6 has a plurality of electrolyte particles 60 and a plurality of pores 62. Each of the plurality of electrolyte particles 60 contains an oxide. Among the plurality of electrolyte particles 60, adjacent electrolyte particles 60 are partitioned by grain boundaries 61. The plurality of electrolyte particles 60 include first particles and second particles.

[0080] Also, the plurality of pores 62 include first pores 62a that are in contact with the first particles and are located at the grain boundaries 61, and second pores 62b that are located inside the second particles.

[0081] The solid electrolyte layer 6 has a plurality of pores 62 including first pores 62a and second pores 62b, so that, for example, cracks, peeling, etc. caused by thermal expansion and / or thermal contraction are less likely to occur. Thereby, the solid electrolyte layer 6 and the cell 1A having such a solid electrolyte layer 6 have improved durability, for example, as compared with the case where the plurality of pores 62 do not include the first pores 62a and the second pores 62b.

[0082] Also, in the cross section shown in FIG. 7, the number of the first pores 62a present per unit area may be smaller than that of the second pores 62b. For example, the number of the first pores 62a present per unit area may be 1 / 2 or less of the number of the second pores 62b. Thereby, the solid electrolyte layer 6 and the cell 1A having such a solid electrolyte layer 6 have improved durability because, for example, adjacent electrolyte particles 60 are less likely to peel at the grain boundary 61 as compared with the case where the first pores 62a are more than the second pores 62b.

[0083] [Third Embodiment] FIG. 8 is a perspective view showing an example of an electrochemical cell according to the third embodiment. FIG. 9 is a partial cross-sectional view of the electrochemical cell shown in FIG. 8.

[0084] As shown in FIGS. 8 and 9, the cell 1B has an element portion 3B in which a fuel electrode 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode 8 are laminated, and conductive members 91 and 92. In an electrochemical cell device in which a plurality of flat plate-type cells are laminated, for example, a plurality of cells 1B are electrically connected by conductive members 91 and 92 which are metal layers adjacent to each other. The conductive members 91 and 92 electrically connect adjacent cells 1B to each other and have gas flow paths for supplying gas to the fuel electrode 5 or the air electrode 8.

[0085] As shown in FIG. 9, the cell 1B has a sealing material that hermetically seals the fuel gas flow path and the oxygen-containing gas flow path of the flat plate-type cell stack. The sealing material is a fixing member 96 of the cell and has a joining material 93 and support members 94 and 95 which are frames. The joining material 93 may be glass or a metal material such as silver solder.

[0086] The support member 94 may be a so-called separator that partitions the flow path of the fuel gas and the flow path of the oxygen-containing gas. The materials of the support members 94 and 95 may be, for example, a conductive metal or an insulating ceramic. Either or both of the support members 94 and 95 may be made of an insulating material. When the support member 94 is a metal, the support member 94 may be integrated with the conductive member 92. When the support member 95 is a metal, the support member 95 may be integrated with the conductive member 91.

[0087] Either one of the support members 94 and 95 is insulating, and electrically insulates the two conductive members 91 and 92 sandwiching the flat plate type cell from each other.

[0088] FIG. 10 is an enlarged cross-sectional view of the region R3 shown in FIG. 9. In the cross-section shown in FIG. 10, the solid electrolyte layer 6 has a plurality of electrolyte particles 60 and a plurality of pores 62. Each of the plurality of electrolyte particles 60 contains an oxide. Among the plurality of electrolyte particles 60, adjacent electrolyte particles 60 are partitioned by grain boundaries 61. The plurality of electrolyte particles 60 includes a first particle and a second particle.

[0089] Further, the plurality of pores 62 includes first pores 62a that are in contact with the first particles and located at the grain boundaries 61, and second pores 62b that are located inside the second particles.

[0090] Since the solid electrolyte layer 6 has a plurality of pores 62 including the first pores 62a and the second pores 62b, for example, cracks, peeling, etc. due to thermal expansion and / or thermal contraction are less likely to occur. Thereby, the solid electrolyte layer 6 and the cell 1B having such a solid electrolyte layer 6 have improved durability, for example, as compared with the case where the plurality of pores 62 do not include the first pores 62a and the second pores 62b.

[0091] Further, in the cross-section shown in FIG. 10, the number of the first pores 62a present per unit area may be smaller than that of the second pores 62b. For example, the number of the first pores 62a present per unit area may be 1 / 2 or less of the number of the second pores 62b. Thereby, the solid electrolyte layer 6 and the cell 1B having such a solid electrolyte layer 6 are less likely to have adjacent electrolyte particles 60 peeled off at the grain boundaries 61 as compared with, for example, the case where the first pores 62a are more numerous than the second pores 62b, and thus the durability is improved.

[0092] [Fourth Embodiment] FIG. 11A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. FIGS. 11B and 11C are cross-sectional views showing other examples of the electrochemical cell according to the fourth embodiment. FIG. 12 is an enlarged view of a region R4 shown in FIG. 11A. Note that FIG. 12 is also applicable to the examples of FIGS. 11B and 11C.

[0093] As shown in FIGS. 11A to 11C, the cell 1C includes an element portion 3C in which a fuel electrode 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode 8 are laminated, and a support substrate 2. The support substrate 2 has through-holes or pores at a portion in contact with the element portion 3C and has a member 120 located outside the gas flow path 2a. The support substrate 2 can allow gas to flow between the gas flow path 2a and the element portion 3C. The support substrate 2 may be formed of, for example, one or a plurality of metal plates. The material of the metal plate may contain chromium. The metal plate may have a conductive coating layer. The support substrate 2 electrically connects adjacent cells 1C to each other. The element portion 3C may be directly formed on the support substrate 2 or may be joined to the support substrate 2 with a joining material.

[0094] In the example shown in FIG. 11A, the side surface of the fuel electrode 5 is covered with the solid electrolyte layer 6, and the gas flow path 2a through which fuel gas flows is hermetically sealed. As shown in FIG. 11B, the side surface of the fuel electrode 5 may be covered with a dense glass or ceramic sealing material 9 and sealed. The sealing material 9 covering the side surface of the fuel electrode 5 may have electrical insulation.

[0095] Further, the gas flow path 2a of the support substrate 2 may be formed by a member 120 having irregularities as shown in FIG. 11C.

[0096] In the cross section shown in FIG. 12, the solid electrolyte layer 6 has a plurality of electrolyte particles 60 and a plurality of pores 62. Each of the plurality of electrolyte particles 60 contains an oxide. Among the plurality of electrolyte particles 60, adjacent electrolyte particles 60 are partitioned by grain boundaries 61. The plurality of electrolyte particles 60 includes a first particle and a second particle.

[0097] Further, the plurality of pores 62 includes a first pore 62a that is in contact with the first particle and is located at the grain boundary 61, and a second pore 62b that is located inside the second particle.

[0098] By having the plurality of pores 62 including the first pore 62a and the second pore 62b, the solid electrolyte layer 6 is less likely to crack, peel, etc. due to, for example, thermal expansion and / or thermal contraction. Thereby, the solid electrolyte layer 6 and the cell 1C having such a solid electrolyte layer 6 have improved durability as compared to, for example, the case where the plurality of pores 62 do not include the first pore 62a and the second pore 62b.

[0099] Also, in the cross section shown in FIG. 12, the number of the first pores 62a present per unit area may be smaller than that of the second pores 62b. For example, the number of the first pores 62a present per unit area may be 1 / 2 or less of the number of the second pores 62b. Thereby, the solid electrolyte layer 6 and the cell 1C having such a solid electrolyte layer 6 have improved durability because adjacent electrolyte particles 60 are less likely to peel at the grain boundary 61 as compared to, for example, the case where the first pores 62a are more than the second pores 62b.

[0100] [Other Embodiments] Next, an electrochemical cell device according to other embodiments will be described.

[0101] In the above-described embodiments, fuel cell, fuel cell stack device, fuel cell module, and fuel cell device were shown as examples of the "electrochemical cell", "electrochemical cell device", "module", and "module housing device". However, as other examples, an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device may be used, respectively. The electrolytic cell has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen or decomposes carbon dioxide into carbon monoxide and oxygen by supplying power. Further, in each of the above-described embodiments, an oxide ion conductor or a hydrogen ion conductor was shown as an example of the electrolyte material of the electrochemical cell, but a hydroxide ion conductor may also be used. According to such an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, durability can be improved.

[0102] As described above in detail, the present disclosure is not limited to the above-described embodiments, and various changes, improvements, etc. are possible without departing from the gist of the present disclosure.

[0103] In one embodiment, (1) the solid electrolyte layer has a plurality of electrolyte particles containing an oxide and a plurality of pores, the plurality of electrolyte particles include first particles and second particles, the plurality of pores include first pores and second pores, the first pores are in contact with the first particles, the second pores are inside the second particles.

[0104] (2) In the solid electrolyte layer of (1) above, in the cross section of the solid electrolyte layer, the number of the first pores present per unit area may be less than that of the second pores.

[0105] (3) In the solid electrolyte layer of (2) above, the number of the first pores present per unit area may be 1 / 2 or less of the number of the second pores.

[0106] (4) In any one of the solid electrolyte layers of (1) to (3) above, in the cross-section of the solid electrolyte layer, the first diameter, which is the average diameter of the first pores, may be smaller than the second diameter, which is the average diameter of the second pores.

[0107] (5) In the solid electrolyte layer of (4) above, the second diameter may be 1 μm or less.

[0108] (6) In the solid electrolyte layer of (4) or (5) above, the first diameter may be 0.3 μm or less.

[0109] (7) In any one of the solid electrolyte layers of (1) to (6) above, in the cross-section of the solid electrolyte layer, the plurality of pores may have an area ratio of 2% or less.

[0110] In one embodiment, (8) The electrochemical cell includes any one of the solid electrolyte layers of (1) to (7) above.

[0111] In one embodiment, (9) The electrochemical cell device has a cell stack including the electrochemical cell of (8) above.

[0112] In one embodiment, (10) The module includes the electrochemical cell device of (9) above and a storage container for storing the electrochemical cell device.

[0113] In one embodiment, (11) The module housing device includes the module of (10) above, auxiliary equipment for operating the module, and an exterior case for housing the module and the auxiliary equipment.

[0114] It should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. In fact, the above-described embodiments can be embodied in various forms. Also, the above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and spirit of the appended claims.

Description of Symbols

[0115] 1,1A~1C cells 2 support substrates 3 element parts 4 interconnector 5 fuel electrode 6 solid electrolyte layer 7 intermediate layer 8 air electrode 10 cell stack device 11 cell stack 12 fixing member 13 fixing material 14 supporting member 15 support 16 gas tank 17 end current collecting member 18 connecting member 60 electrolyte particles 61 grain boundaries 62 pores 62a first pore 62b second pore 100 module 110 module housing device

Claims

1. It has a plurality of electrolyte particles containing an oxide and a plurality of pores, The plurality of electrolyte particles include a first particle and a second particle, The plurality of pores include a first pore and a second pore, The first pore is in contact with the first particle, The second pore is inside the second particle Solid electrolyte layer.

2. In the cross-section of the solid electrolyte layer, the number of the first pores present per unit area is less than that of the second pores The solid electrolyte layer according to Claim 1.

3. The number of the first pores present per unit area is 1 / 2 or less of the number of the second pores The solid electrolyte layer according to Claim 2.

4. In the cross-section of the solid electrolyte layer, a first diameter which is the average diameter of the first pores is smaller than a second diameter which is the average diameter of the second pores The solid electrolyte layer according to Claim 1.

5. The second diameter is 1 μm or less The solid electrolyte layer according to Claim 4.

6. The first diameter is 0.3 μm or less The solid electrolyte layer according to Claim 4.

7. In the cross-section of the solid electrolyte layer, the area ratio of the plurality of pores is 2% or less The solid electrolyte layer according to Claim 1.

8. An electrochemical cell including the solid electrolyte layer according to any one of Claims 1 to 7.

9. It has a cell stack including the electrochemical cell according to Claim 8 Electrochemical cell device.

10. The electrochemical cell device according to Claim 9, and A storage container for storing the electrochemical cell device Module comprising.

11. The module according to Claim 10, Auxiliary equipment for operating the module, An exterior case for housing the module and the auxiliary equipment Module housing device comprising.

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