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

Abstract

The solid electrolyte layer has a first surface and a second surface opposed to each other in a thickness direction, and has a plurality of electrolyte particles including an oxide. The plurality of electrolyte particles include a first particle and a second particle. The first particle is in contact with both the first surface and the second surface. The second particle is in contact with one of the first surface and the second surface and is located away from the other surface.

Description

[Technical field]

[0001] The present disclosure relates to solid electrolyte layers, electrochemical cells, electrochemical cell devices, modules and module housing devices. [Background technology]

[0002] In recent years, various fuel cell stack devices including a plurality of fuel cells have been proposed as next-generation energy sources. A fuel cell is a type of cell that can generate 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] JP 2017-147030 A Summary of the Invention

[0004] A solid electrolyte layer according to one aspect of the embodiment has a first surface and a second surface opposed to each other in a thickness direction, and includes a plurality of electrolyte particles including an oxide. The plurality of electrolyte particles include a first particle and a second particle. The first particle is in contact with both the first surface and the second surface. The second particle is in contact with one of the first surface and the second surface and is located away from the other.

[0005] The electrochemical cell of the present disclosure also includes the solid electrolyte layer described above.

[0006] The electrochemical cell device of the present disclosure also includes a cell stack including the electrochemical cell described above.

[0007] The module of the present disclosure includes the electrochemical cell device described above and a container for housing the electrochemical cell device.

[0008] The module housing device of the present disclosure includes the above-described module, an auxiliary device for operating the module, and an exterior case for housing the module and the auxiliary device. [Brief description of the drawings]

[0009] [Figure 1A] FIG. 1A is a cross-sectional view illustrating an example of an electrochemical cell according to a first embodiment. [Figure 1B] 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. [Figure 1C] FIG. 1C is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the interconnector side. [Figure 2A] FIG. 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. [Figure 2B] FIG. 2B is a cross-sectional view taken along line XX shown in FIG. 2A. [Figure 2C] FIG. 2C is a top view illustrating an example of the electrochemical cell device according to the first embodiment. [Diagram 3] FIG. 3 is an enlarged cross-sectional view of a region R1 shown in FIG. 1A. [Figure 4] FIG. 4 is an external perspective view illustrating an example of the module according to the first embodiment. [Diagram 5] FIG. 5 is an exploded perspective view illustrating an example of a module housing device according to the first embodiment. [Figure 6A] FIG. 6A is a cross-sectional view showing an example of an electrochemical cell device according to a second embodiment. [Figure 6B] FIG. 6B is a cross-sectional view showing an electrochemical cell according to a second embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a region R2 shown in FIG. 6B. [Figure 8] FIG. 8 is a perspective view illustrating an example of an electrochemical cell according to the third embodiment. [Figure 9] FIG. 9 is a partial cross-sectional view of the electrochemical cell shown in FIG. [Figure 10]FIG. 10 is an enlarged cross-sectional view of a region R3 shown in FIG. [Figure 11A] FIG. 11A is a cross-sectional view illustrating an example of an electrochemical cell according to a fourth embodiment. [Figure 11B] FIG. 11B is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 11C] FIG. 11C is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 12] FIG. 12 is an enlarged cross-sectional view of a region R4 shown in FIG. 11A. [Figure 13] FIG. 13 is a diagram showing the evaluation results of Samples 1 to 5. [Figure 14] FIG. 14 is a diagram showing the evaluation results of Samples 1 and 6 to 9. [Figure 15] FIG. 15 is a diagram showing the evaluation results of Samples 1 and 10 to 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Conventional fuel cell stack devices have room for improvement in terms of power generation performance.

[0011] Therefore, it is desirable to provide a solid electrolyte layer, an electrochemical cell, an electrochemical cell device, a module, and a module housing device that can improve performance.

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

[0013] In addition, it should be noted that the drawings are schematic, and that the dimensional relationships, ratios, etc. of each element may differ from the reality. Furthermore, there may be cases where the dimensional relationships, ratios, etc. of each element differ from those of the drawings.

[0014] [First embodiment] <Electrochemical cell configuration> First, with reference to Figures 1A to 1C, an electrochemical cell according to a first embodiment will be described using an example of a solid oxide 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 will be simply referred to as a cell stack device.

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

[0016] 1A to 1C, cell 1 is a hollow flat plate-like elongated plate. As shown in Fig. 1B, the shape of the entire cell 1 as viewed from the side may be, for example, a rectangle with a side length in a length direction L of 5 cm to 50 cm and a length in a width direction W perpendicular to the length direction L of, for example, 1 cm to 10 cm. The thickness of the entire cell 1 in a thickness direction T may be, for example, 1 mm to 5 mm.

[0017] 1A, the cell 1 includes a conductive supporting substrate 2, an element portion 3, and an interconnector 4. The supporting substrate 2 is columnar having a pair of opposing flat surfaces, n1 and n2, and a pair of arc-shaped side surfaces m connecting the surfaces n1 and n2.

[0018] The element section 3 is located on a surface n1 of the support substrate 2. The element section 3 has a fuel electrode 5, a solid electrolyte layer 6, an intermediate layer 7, and a cathode 8.

[0019] 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 face n1. 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, the solid electrolyte layer 6 is exposed on the surface of a pair of arc-shaped side faces m of the cell 1. The interconnector 4 does not have to extend to the lower end of the cell 1.

[0020] Each of the members constituting the cell 1 will be described below.

[0021] The support substrate 2 has therein gas flow channels 2a through which gas flows. The example of the support substrate 2 shown in FIG. 1A has six gas flow channels 2a. The support substrate 2 has gas permeability and allows the fuel gas flowing through the gas flow channels 2a to permeate to the anode 5. The support substrate 2 may be conductive. The conductive support substrate 2 collects electricity generated in the element section 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, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0023] The material of the fuel electrode 5 may be a generally known material. The fuel electrode 5 may be made of a porous conductive ceramic, such as a ceramic containing calcium oxide, magnesium oxide, or ZrO2 in which a rare earth element oxide is dissolved, and Ni and / or NiO. The rare earth element oxide may contain a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or ZrO2 in which a rare earth element oxide is dissolved may be referred to as stabilized zirconia. The stabilized zirconia may also include partially stabilized zirconia.

[0024] The solid electrolyte layer 6 is an electrolyte and 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 leakage of the fuel gas and oxygen-containing gas to occur.

[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 dissolved. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may include, for example, ZrO2 in which Yb, Sc, or Gd is dissolved, or BaZrO3 in which Sc, Y, or Yb is dissolved. 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 Sr (strontium) contained in the air electrode 8, which will be described later, to diffuse into the solid electrolyte layer 6, thereby making it difficult for a resistive layer of SrZrO3 to form on the solid electrolyte layer 6.

[0027] The material of the intermediate layer 7 is not particularly limited as long as it generally prevents diffusion of elements 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 a rare earth element other than Ce (cerium) is dissolved. As such a rare earth element, Gd (gadolinium), Sm (samarium), or the like 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, and particularly in the range of 30% to 50%.

[0029] There are no particular limitations on the material of the air electrode 8 as long as it is a material 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. 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. Note that x is 0 <x<1、yは0<y<1である。

[0031] Moreover, the interconnector 4 is dense and prevents leakage of the fuel gas flowing through the gas flow passage 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0032] Lanthanum chromite-based perovskite oxides (LaCrO3-based oxides), lanthanum strontium titanium-based perovskite oxides (LaSrTiO3-based oxides), etc. may be used as the material for the interconnector 4. These materials are conductive and are not easily reduced or oxidized even when in contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

[0033] <Configuration of electrochemical cell device> Next, an electrochemical cell device according to the present embodiment using the above-mentioned cell 1 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 line XX 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 a thickness direction T of the cells 1 (see FIG. 1A), 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. The support member 14 also has a support body 15 and a gas tank 16. The support body 15 and the gas tank 16, which are the support member 14, are made of, for example, metal.

[0036] 2B, the support 15 has insertion holes 15a into which the lower ends of the multiple cells 1 are inserted. The lower ends of the multiple cells 1 and the inner wall of the insertion holes 15a are joined with a fixing material 13.

[0037] The gas tank 16 has an opening for supplying a reaction gas to the cells 1 through the insertion holes 15a, and a groove 16a located around the opening. The outer peripheral edge of the support 15 is joined to the gas tank 16 by a joining material 21 filled in the groove 16a of the gas tank 16.

[0038] In the example shown in Fig. 2A, fuel gas is stored in an internal space 22 formed by a support body 15, which is the 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 in a reformer 102 (see Fig. 4), which will be described later.

[0039] The hydrogen-rich fuel gas can be produced by steam reforming of the raw fuel, etc. When the fuel gas is produced by steam reforming, the fuel gas contains water vapor.

[0040] The example shown in FIG. 2A includes 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 of the supports 15. The gas tank 16 has two through holes on the upper surface. Each of the supports 15 is disposed in each of the through holes. An internal space 22 is formed by the one gas tank 16 and the two supports 15.

[0041] The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. For example, the length of the insertion hole 15a in the arrangement direction of the cells 1, i.e., the thickness direction T, is greater than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. The width of the insertion hole 15a is, for example, greater than the length of the cell 1 in the width direction W (see FIG. 1A).

[0042] 2B, the joints between the inner walls of the insertion holes 15a and the lower ends of the cells 1 are filled with a fixing material 13 and solidified. This bonds and fixes the inner walls of the insertion holes 15a to the lower ends of the cells 1, respectively, and also bonds and fixes the lower ends of the cells 1 to each other. The gas flow paths 2a of each cell 1 communicate with the internal space 22 of the support member 14 at their lower ends.

[0043] A material having low electrical conductivity, such as glass, can be used for the fixing material 13 and the bonding material 21. Specific materials for the fixing material 13 and the bonding material 21 include amorphous glass, and in particular, crystallized glass.

[0044] As the crystallized glass, for example, any of materials such as SiO2-CaO, MgO-B2O3, La2O3-B2O3-MgO, La2O3-B2O3-ZnO, and SiO2-CaO-ZnO may be used, and in particular, SiO2-MgO-based materials may be used.

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

[0046] As shown in Fig. 2B, an end current collecting member 17 is electrically connected to the cell 1 located at the outermost position in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive part 19 protruding to the outside of the cell stack 11. The conductive part 19 collects electricity generated by power generation in the cells 1 and draws it out to the outside. Note that the end current collecting member 17 is not shown in Fig. 2A.

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

[0048] The positive electrode terminal 19A is a positive electrode when the electric power generated by the cell stack 11 is output to the outside, and is electrically connected to the end current collecting member 17 on the positive electrode side of the cell stack 11A. The negative electrode terminal 19B is a negative electrode when the electric power generated by the cell stack 11 is output to the outside, and is electrically connected to the end current collecting member 17 on the negative electrode side of the cell stack 11B.

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

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

[0051] 3, the solid electrolyte layer 6 has a first surface 6a and a second surface 6b that face each other 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 .

[0052] The solid electrolyte layer 6 has a plurality of electrolyte particles 61. Each of the plurality of electrolyte particles 61 includes an oxide. Adjacent electrolyte particles 61 are separated by grain boundaries 60.

[0053] The electrolyte particles 61 include a first particle 61a and a second particle 61b. The first particle 61a is an electrolyte particle 61 that contacts both the first surface 6a and the second surface 6b. The second particle 61b is an electrolyte particle 61 that contacts one of the first surface 6a and the second surface 6b and is located away from the other.

[0054] The solid electrolyte layer 6 includes the first particles 61a, which, for example, improves ion conductivity in the thickness direction T of the solid electrolyte layer 6. The solid electrolyte layer 6 includes the second particles 61b, which, for example, relieves stress generated inside the solid electrolyte layer 6 and improves durability. Therefore, the solid electrolyte layer 6 according to this embodiment improves the performance of the cell 1.

[0055] Additionally, the plurality of electrolyte particles 61 may further include a third particle 61c located away from both the first surface 6a and the second surface 6b, thereby further improving the performance of the cell 1.

[0056] 3, i.e., the cross section of the solid electrolyte layer 6 intersecting the first surface 6a and the second surface 6b, the area ratio of the first particles 61a may be 4% or more and 70% or less. By setting the area ratio of the first particles 61a to 4% or more, the ion conductivity in the thickness direction T of the solid electrolyte layer 6 is improved. By setting the area ratio of the first particles 61a to 70% or less, the solid electrolyte layer 6 includes the second particles 61b and the third particles 61c in an appropriate amount, which relieves stress generated inside the solid electrolyte layer 6 and improves durability.

[0057] 3, the solid electrolyte layer 6 may include first particles 61a having a diameter (equivalent circle diameter) larger than the average thickness t of the solid electrolyte layer 6. This improves the ionic conductivity in the thickness direction T of the solid electrolyte layer 6 over a wide range.

[0058] 3, the solid electrolyte layer 6 may include first particles 61a having a diameter (equivalent circle diameter) smaller than the average thickness t of the solid electrolyte layer 6. This reduces the porosity of the solid electrolyte layer 6, making it less likely that the movement of ions inside the solid electrolyte layer 6 will be hindered by the pores, and improves ion conductivity.

[0059] 3, the solid electrolyte layer 6 may include one or more, particularly one to five, first particles 61a on the first surface 6a or the second surface 6b within a range of a length corresponding to the average thickness t of the solid electrolyte layer 6. This allows ions to move smoothly between the first surface 6a and the second surface 6b of the solid electrolyte layer 6.

[0060] Furthermore, the solid electrolyte layer 6 may have the first particles 61a in a proportion of 2% to 50% by number among the plurality of electrolyte particles 61. This improves the ion conductivity in the thickness direction T of the solid electrolyte layer 6, relieves stress generated inside the solid electrolyte layer 6, and improves durability.

[0061] The solid electrolyte layer 6 may have an average of 1.3 to 5 electrolyte particles 61 between the first surface 6a and the second surface 6b, which reduces stress generated inside the solid electrolyte layer 6 and improves durability.

[0062] Here, the arrangement and diameter of the electrolyte particles 61 in the solid electrolyte layer 6 can be measured, for example, by using a SEM (scanning electron microscope) and an EDX (energy dispersive X-ray analyzer) to measure the cross section of the element portion 3. Specifically, the cross section of the solid electrolyte layer 6 is photographed with an SEM at a magnification of, for example, 2000 times, and the obtained cross section photograph is subjected to image analysis to calculate the diameters of 200 or more electrolyte particles 61. The diameter of the electrolyte particles 61 may be determined, for example, by measuring the perimeter of the electrolyte particles 61 using image analysis software and converting the perimeter into a circle equivalent diameter. The area ratio, number ratio, etc. of the first particles 61a can be confirmed by image analysis of the cross section photograph.

[0063] The number of first particles 61a contained within a square having one side equal to the average thickness of the solid electrolyte layer 6 can be calculated, for example, as follows. First, the average thickness of the solid electrolyte layer 6 is calculated using a cross-sectional photograph of the solid electrolyte layer 6. Next, a square having one side equal to the calculated average thickness of the solid electrolyte layer 6 is superimposed on the cross-sectional photograph of the solid electrolyte layer 6 such that its center overlaps with the bisector that divides the cross section of the solid electrolyte layer 6 in half in the thickness direction, and two opposing sides of the square are along the first surface 6a and the second surface 6b, respectively. At this time, the number of first particles 61a overlapping the square may be counted.

[0064] Furthermore, the number of electrolyte particles 61 located between the first surface 6a and the second surface 6b can be calculated by counting the number of electrolyte particles 61 located on a line segment in the thickness direction that is tangent to the first surface 6a and the second surface 6b in a cross-sectional photograph of the solid electrolyte layer 6 at, for example, 10 or more locations, and calculating the average.

[0065] <module> Next, a module according to an embodiment of the present disclosure using the electrochemical cell device described above will be described with reference to Fig. 4. Fig. 4 is an external perspective view showing a module according to a first embodiment. Fig. 4 shows a state in which the front and rear surfaces, which are part of the storage container 101, have been removed and the cell stack device 10 of the fuel cell stored inside has been removed to the rear.

[0066] 4, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container. In addition, above the cell stack device 10, a reformer 102 is disposed.

[0067] The reformer 102 reforms raw fuel such as natural gas or kerosene to generate fuel gas and supplies it to the cell 1. The raw fuel is supplied to the reformer 102 through a raw fuel supply pipe 103. The reformer 102 may include a vaporizer 102a that vaporizes water, and a reformer 102b. The reformer 102b includes a reforming catalyst (not shown) and reforms the raw fuel into fuel gas. Such a reformer 102 can perform steam reforming, which is a highly efficient reforming reaction.

[0068] The fuel gas generated in the reformer 102 is supplied to the gas flow channel 2a of the cell 1 (see FIG. 1A) through the gas distribution pipe 20, the gas tank 16, and the support member 14.

[0069] Furthermore, in the module 100 having the above-mentioned configuration, the temperature inside the module 100 during normal power generation becomes approximately 500°C to 1000°C as the gas is combusted and the cells 1 generate power.

[0070] In such a module 100, as described above, by accommodating the cell stack device 10 having the cells 1 whose performance is improved, it is possible to make the module 100 have improved performance.

[0071] <Module storage device> Fig. 5 is an exploded perspective view showing an example of a module housing device according to the first embodiment. A module housing device 110 according to this 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 in the exterior case 111. Note that some components are omitted in Fig. 5.

[0072] An exterior case 111 of a module accommodating device 110 shown in Fig. 5 has support columns 112 and an exterior plate 113. A partition plate 114 divides the interior of the exterior case 111 into upper and lower sections. The space above the partition plate 114 in the exterior case 111 is a module accommodating chamber 115 that accommodates the module 100, and the space below the partition plate 114 in the exterior case 111 is an auxiliary equipment accommodating chamber 116 that accommodates auxiliary equipment that operates the module 100. Note that in Fig. 5, the auxiliary equipment accommodated in the auxiliary equipment accommodating chamber 116 is omitted.

[0073] In addition, the partition plate 114 has an air flow port 117 for allowing air from the auxiliary equipment housing chamber 116 to flow toward the module housing chamber 115. The exterior plate 113 constituting the module housing chamber 115 has an exhaust port 118 for exhausting air from within the module housing chamber 115.

[0074] In such a module housing device 110, as described above, by accommodating the module 100 whose performance is improved in the module housing chamber 115, it is possible to provide a module housing device 110 whose performance is improved.

[0075] In the above embodiment, a case where a hollow flat support substrate is used is exemplified, but the present invention can also be applied to a cell stack device that uses a cylindrical support substrate.

[0076] [Second embodiment] Next, an electrochemical cell and an electrochemical cell device according to a second embodiment will be described with reference to FIGS. 6A to 7. FIG.

[0077] In the above-described embodiment, a so-called "vertical stripe type" has been exemplified in which only one element unit including a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the surface of a supporting substrate. However, the present invention can also be applied to a horizontal stripe type electrochemical cell device in which so-called "horizontal stripe type" electrochemical cells are arranged in which element units are provided at multiple locations spaced apart from each other on the surface of a supporting substrate and adjacent element units are electrically connected.

[0078] Fig. 6A is a cross-sectional view showing an example of an electrochemical cell device according to a second embodiment. Fig. 6B is a transverse cross-sectional view showing an electrochemical cell according to a second embodiment. Fig. 7 is an enlarged view of a region R2 shown in Fig. 6B.

[0079] 6A, in the cell stack device 10A, multiple cells 1A extend in a longitudinal direction L from a pipe 22a through which a fuel gas flows. The cells 1A have multiple element portions 3 on a support substrate 2. A gas flow path 2a through which the fuel gas flows from the pipe 22a is provided inside the support substrate 2.

[0080] Moreover, the cells 1A are electrically connected to each other via connection members 31. The connection members 31 are located between the element portions 3 of the respective cells 1A, and connect the adjacent cells 1A.

[0081] 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 is columnar and has a pair of opposing flat surfaces n1, n2, and a pair of arc-shaped side surfaces m connecting the surfaces n1, n2.

[0082] The pair of element portions 3 are located opposite each other on the surfaces n1, n2 of the support substrate 2. The sealing portion 30 is located so as to cover the side surface m of the support substrate 2.

[0083] 7, the solid electrolyte layer 6 has a first surface 6a and a second surface 6b that face each other 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 .

[0084] The solid electrolyte layer 6 has a plurality of electrolyte particles 61. Each of the plurality of electrolyte particles 61 includes an oxide. Adjacent electrolyte particles 61 are separated by grain boundaries 60.

[0085] The electrolyte particles 61 include a first particle 61a and a second particle 61b. The first particle 61a is an electrolyte particle 61 that contacts both the first surface 6a and the second surface 6b. The second particle 61b is an electrolyte particle 61 that contacts one of the first surface 6a and the second surface 6b and is located away from the other.

[0086] The solid electrolyte layer 6 includes the first particles 61a, which, for example, improves ion conductivity in the thickness direction T of the solid electrolyte layer 6. Furthermore, the solid electrolyte layer 6 includes the second particles 61b, which, for example, relieves stress generated inside the solid electrolyte layer 6 and improves durability. Therefore, the solid electrolyte layer 6 according to this embodiment improves the performance of the cell 1A.

[0087] [Third embodiment] Fig. 8 is a perspective view showing an example of an electrochemical cell according to the third embodiment, and Fig. 9 is a partial cross-sectional view of the electrochemical cell shown in Fig. 8.

[0088] 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 stacked, and conductive members 91, 92. In an electrochemical cell device in which a plurality of flat cell types are stacked, for example, the plurality of cells 1B are electrically connected by conductive members 91, 92 which are adjacent metal layers. The conductive members 91, 92 electrically connect the adjacent cells 1B to each other, and have a gas flow path for supplying gas to the fuel electrode 5 or the air electrode 8.

[0089] 9, cell 1B has a sealing material that hermetically seals the fuel gas flow path and the oxygen-containing gas flow path of the flat cell stack. The sealing material is a fixing member 96 for the cell, and has a bonding material 93 and support members 94, 95 that are frames. The bonding material 93 may be glass or a metal material such as silver solder.

[0090] The support member 94 may be a so-called separator that separates the fuel gas flow path from the oxygen-containing gas flow path. The material of the support members 94, 95 may be, for example, a conductive metal or an insulating ceramic. When the support member 94 is made of a metal, the support member 94 may be integrated with the conductive member 92. When the support member 95 is made of a metal, the support member 95 may be integrated with the conductive member 91.

[0091] Either the bonding material 93 or the support members 94, 95 is insulating, and electrically insulates the two conductive members 91, 92 that sandwich the flat cell from each other.

[0092] Fig. 10 is an enlarged cross-sectional view of region R3 shown in Fig. 9. As shown in Fig. 10, solid electrolyte layer 6 has a first surface 6a and a second surface 6b facing each other in a 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.

[0093] The solid electrolyte layer 6 has a plurality of electrolyte particles 61. Each of the plurality of electrolyte particles 61 includes an oxide. Adjacent electrolyte particles 61 are separated by grain boundaries 60.

[0094] The electrolyte particles 61 include a first particle 61a and a second particle 61b. The first particle 61a is an electrolyte particle 61 that contacts both the first surface 6a and the second surface 6b. The second particle 61b is an electrolyte particle 61 that contacts one of the first surface 6a and the second surface 6b and is located away from the other.

[0095] The solid electrolyte layer 6 includes the first particles 61a, which, for example, improves ion conductivity in the thickness direction T of the solid electrolyte layer 6. The solid electrolyte layer 6 includes the second particles 61b, which, for example, relieves stress generated inside the solid electrolyte layer 6 and improves durability. Therefore, the solid electrolyte layer 6 according to this embodiment improves the performance of the cell 1B.

[0096] [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 another example of an electrochemical cell according to the fourth embodiment. Fig. 12 is an enlarged view of a region R4 shown in Fig. 11A. Fig. 12 can also be applied to the examples of Figs. 11B and 11C.

[0097] As shown in FIG. 11A to FIG. 11C, the cell 1C has an element section 3C in which an anode 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 a through hole or a fine hole at a portion in contact with the element section 3C, and has a member 120 located outside the gas flow path 2a. The support substrate 2 can distribute gas between the gas flow path 2a and the element section 3C. The support substrate 2 may be composed of, for example, one or more 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 the adjacent cells 1C to each other. The element section 3C may be formed directly on the support substrate 2, or may be bonded to the support substrate 2 by a bonding material.

[0098] In the example shown in Fig. 11A, the side surface of the anode 5 is covered with a solid electrolyte layer 6, which airtightly seals a gas flow channel 2a through which the fuel gas flows. As shown in Fig. 11B, the side surface of the anode 5 may be covered and sealed with a dense glass or ceramic sealant 9. The sealant 9 covering the side surface of the anode 5 may have electrical insulation properties.

[0099] Furthermore, the gas flow path 2a of the support substrate 2 may be formed by a member 120 having projections and recesses as shown in FIG. 11C.

[0100] 12, the solid electrolyte layer 6 has a first surface 6a and a second surface 6b that face each other 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 .

[0101] The solid electrolyte layer 6 has a plurality of electrolyte particles 61. Each of the plurality of electrolyte particles 61 includes an oxide. Adjacent electrolyte particles 61 are separated by grain boundaries 60.

[0102] The electrolyte particles 61 include a first particle 61a and a second particle 61b. The first particle 61a is an electrolyte particle 61 that contacts both the first surface 6a and the second surface 6b. The second particle 61b is an electrolyte particle 61 that contacts one of the first surface 6a and the second surface 6b and is located away from the other.

[0103] The solid electrolyte layer 6 includes the first particles 61a, which, for example, improves ion conductivity in the thickness direction T of the solid electrolyte layer 6. The solid electrolyte layer 6 includes the second particles 61b, which, for example, relieves stress generated inside the solid electrolyte layer 6 and improves durability. Therefore, the solid electrolyte layer 6 according to this embodiment improves the performance of the cell 1C.

[0104] [Other embodiments] Next, electrochemical cell devices according to other embodiments will be described.

[0105] In the above-mentioned embodiments, a solid oxide fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as examples of the "electrochemical cell", "electrochemical cell device", "module", and "module housing device", but other examples may be a solid oxide electrolysis cell, an electrolysis cell stack device, an electrolysis module, and an electrolysis device, respectively. The electrolysis cell has a first electrode layer and a second electrode layer, and decomposes water vapor into hydrogen and oxygen, or decomposes carbon dioxide into carbon monoxide and oxygen, when supplied with electric power. In addition, in the above-mentioned embodiments, an oxide ion conductor or a hydrogen ion conductor is shown as an example of the electrolyte material of the electrochemical cell, but a hydroxide ion conductor may also be used. Such an electrolysis cell, an electrolysis cell stack device, an electrolysis module, and an electrolysis device can improve performance. EXAMPLES

[0106] Samples 1 to 13 simulating the solid electrolyte layer 6 were produced and their performance was evaluated.

[0107] (Preparation of Samples 1 to 13) Samples 1 to 13 were fabricated using electrolyte materials with different particle sizes. Two types of ZrO2 material (YSZ material) in which Y2O3 is dissolved at 8 mol% were prepared as electrolyte materials. The two types of YSZ materials were Material A with an average particle size of 1.8 μm and Material B with an average particle size of 0.4 μm.

[0108] Two types of slurries were prepared using material A, material B, a solvent, and a dispersant. Specifically, material A, the solvent, and the dispersant were milled in a ball mill for 10 hours to obtain slurry A. Material B, the solvent, and the dispersant were milled in a ball mill for 10 hours to obtain slurry B. The obtained slurry A and slurry B were mixed in various ratios and dried to obtain mixed powders.

[0109] The resistance of the solid electrolyte layer 6 was evaluated by producing a single cell having the solid electrolyte layer 6 using the above-mentioned mixed powder, the fuel electrode 5, the intermediate layer 7 and the air electrode 8, and measuring the resistance of the single cell.

[0110] The single cell was produced as follows. A laminated sheet was obtained by laminating a sheet for a solid electrolyte layer produced using the above-mentioned mixed powder on a sheet for a fuel electrode. The obtained laminated sheet was degreased and then fired in air at 1500°C to obtain a laminated sintered body. A slurry for an intermediate layer was printed on the solid electrolyte layer of the obtained laminated sintered body, and after degreasing, it was fired in air at 1350°C. Thereafter, a slurry for an air electrode was further printed, degreased, and then fired in air at 1150°C to obtain a single cell having a solid electrolyte layer 6 with a different content of the first particles 61a.

[0111] (Evaluation of Samples 1 to 13) For samples 1 to 13, the area ratio of the first particles 61a in the solid electrolyte layer 6, the number ratio of the first particles 61a, the average number of the first particles 61a between the first surface 6a and the second surface 6b, and the resistance of the single cell were measured. FIG. 13 is a diagram showing the evaluation results of samples 1 to 5. FIG. 14 is a diagram showing the evaluation results of samples 1 and 6 to 9. FIG. 15 is a diagram showing the evaluation results of samples 1 and 10 to 13. The area ratio of the first particles 61a in the solid electrolyte layer, the number ratio of the first particles 61a, and the average number of the first particles 61a between the first surface and the second surface were evaluated by observing a cross section along the stacking direction of the single cell using a scanning electron microscope (SEM). The resistance is an ohmic resistance measured by an AC impedance method.

[0112] As shown in FIGS. 13 to 15, Samples 2 to 13, which contain the first particles 61a other than Sample 1, exhibited lower resistance than Sample 1, which does not contain the first particles.

[0113] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible without departing from the gist of the present disclosure.

[0114] In one embodiment, (1) a solid electrolyte layer has a first surface and a second surface opposed to each other in a thickness direction, and has a plurality of electrolyte particles containing an oxide, The plurality of electrolyte particles include a first particle in contact with both the first surface and the second surface; a second particle located in contact with one of the first surface and the second surface and spaced apart from the other of the first surface and the second surface; Includes.

[0115] (2) In the solid electrolyte layer of (1) above, the plurality of electrolyte particles may include third particles positioned away from both the first surface and the second surface.

[0116] (3) In the solid electrolyte layer of (1) or (2) above, an area ratio of the first particles in a cross section intersecting the first surface and the second surface may be 4% or more and 70% or less.

[0117] (4) The solid electrolyte layer of any one of (1) to (3) above may include the first particles having a diameter larger than an average thickness of the solid electrolyte layer in a cross section intersecting the first surface and the second surface.

[0118] (5) The solid electrolyte layer of any one of (1) to (4) above may include the first particles having a diameter smaller than an average thickness of the solid electrolyte layer in a cross section intersecting the first surface and the second surface.

[0119] (6) The solid electrolyte layer of any one of (1) to (5) above may include one or more of the first particles in a cross section intersecting the first surface and the second surface, within a length range corresponding to an average thickness t of the solid electrolyte layer on the first surface or the second surface.

[0120] (7) In the solid electrolyte layer of any one of the above (1) to (6), the first particles may account for 2% to 50% by number of the plurality of electrolyte particles.

[0121] (8) In any one of the solid electrolyte layers (1) to (7) above, an average of 1.3 to 5 electrolyte particles may be present between the first surface and the second surface.

[0122] In one embodiment, (9) an electrochemical cell includes the solid electrolyte layer according to any one of (1) to (8) above.

[0123] In one embodiment, (10) an electrochemical cell device has a cell stack including the electrochemical cell of (9) above.

[0124] In one embodiment, the module (11) comprises the electrochemical cell device (10) described above, and a container for housing the electrochemical cell device.

[0125] In one embodiment, the module housing device (12) includes the module (11) and Auxiliary equipment for operating the module; and an exterior case that houses the module and the auxiliary equipment.

[0126] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0127] 1,1A~1C Cell 2 Support substrate 3. Element section 4 Interconnector 5 Fuel electrode 6 Solid electrolyte layer 7. Middle Tier 8 Air electrode 10 Cell stack device 11 Cell stack 12 Fixing member 13 Fixing material 14 Support member 15 Support 16 Gas Tank 17 End current collecting member 18 Connection parts 60 grain boundaries 61 Electrolyte particles 100 Modules 110 Module storage device

Claims

1. A solid electrolyte layer having a first surface and a second surface opposed to each other in a thickness direction, the solid electrolyte layer having a plurality of electrolyte particles including an oxide, The plurality of electrolyte particles include a first particle in contact with both the first surface and the second surface; second particles located in contact with one of the first surface and the second surface and spaced apart from the other of the first surface and the second surface; A solid electrolyte layer comprising:

2. The plurality of electrolyte particles includes a third particle located away from both the first surface and the second surface. The solid electrolyte layer according to claim 1 .

3. The area ratio of the first particles in a cross section intersecting the first surface and the second surface is 4% or more and 70% or less. The solid electrolyte layer according to claim 1 .

4. the first particles having a diameter larger than an average thickness of the solid electrolyte layer in a cross section intersecting the first surface and the second surface; The solid electrolyte layer according to claim 1 .

5. The first particles have a diameter smaller than an average thickness of the solid electrolyte layer in a cross section intersecting the first surface and the second surface. The solid electrolyte layer according to claim 1 .

6. In a cross section intersecting the first surface and the second surface, one or more of the first particles are included within a range of a length on the first surface or the second surface that corresponds to an average thickness t of the solid electrolyte layer. The solid electrolyte layer according to claim 1 .

7. Among the plurality of electrolyte particles, the first particles account for 2% or more and 50% or less in terms of number. The solid electrolyte layer according to claim 1 .

8. The electrolyte particles have an average of 1.3 to 5 particles between the first surface and the second surface. The solid electrolyte layer according to claim 1 .

9. An electrochemical cell comprising the solid electrolyte layer according to any one of claims 1 to 8.

10. A cell stack comprising the electrochemical cell according to claim 9. Electrochemical cell setup.

11. The electrochemical cell device according to claim 10 ; A container for housing the electrochemical cell device; A module comprising:

12. A module according to claim 11; Auxiliary equipment for operating the module; an exterior case that houses the module and the auxiliary equipment; A module housing device comprising:

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