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

Abstract

The solid electrolyte layer has a plurality of electrolyte particles containing an oxide. The plurality of electrolyte particles have first particles and second particles. The first particles have a particle diameter of 1 / 10 or more with respect to the average thickness of the solid electrolyte layer. The second particles have a smaller particle diameter than the first particles.

Description

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

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

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

[0003] JP 2001-351647 A JP 2003-317738 A

[0004] A solid electrolyte layer according to one aspect of the embodiment includes a plurality of electrolyte particles containing an oxide. The plurality of electrolyte particles include first particles and second particles. The first particles have a particle size that is 1 / 10 or more of the average thickness of the solid electrolyte layer. The second particles have a particle size smaller than that of the first particles.

[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 that houses the electrochemical cell device.

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

[0009] 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 an example of an electrochemical cell according to the first embodiment, viewed from the air electrode side. FIG. 1C is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the interconnector side. FIG. 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. FIG. 2B is a cross-sectional view taken along line X-X shown in FIG. 2A. FIG. 2C is a top view showing an example of an electrochemical cell device according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of a region R1 shown in FIG. 1A. FIG. 4 is an external perspective view showing an example of a module according to the first embodiment. FIG. 5 is an exploded perspective view schematically showing an example of a module housing device according to the first embodiment. 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 example of an electrochemical cell according to the second embodiment. FIG. 7 is an enlarged cross-sectional view of a region R2 shown in FIG. 6B. FIG. 8 is a perspective view showing an example of an electrochemical cell according to a third embodiment. FIG. 9 is a partial cross-sectional view showing the example of the electrochemical cell shown in FIG. 8. Fig. 10 is an enlarged cross-sectional view of region R3 shown in Fig. 9. Fig. 11A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. Fig. 11B is a cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment. Fig. 11C is a cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment. Fig. 12 is an enlarged cross-sectional view of region R4 shown in Fig. 11A. Fig. 13 is a diagram showing the evaluation results of samples Nos. 1 to 4. Fig. 14 is a diagram showing the evaluation results of samples Nos. 5 to 8.

[0010] The above-described fuel cell stack device has room for improvement in terms of performance.

[0011] Therefore, it is desired 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, 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 the disclosure is not limited to the embodiments described below.

[0013] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0014] 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 an example of an electrochemical cell according to the first embodiment, viewed from the air electrode side. FIG. 1C is a side view of an example of an electrochemical cell according to the first embodiment, viewed 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 also be simply referred to as a cell.

[0016] 1A to 1C, the cell 1 is a hollow, flat, 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 the length direction L of 5 cm to 50 cm and a width direction W perpendicular to the length direction L of 1 cm to 10 cm. The thickness of the entire cell 1 in the thickness direction T may be, for example, 1 mm to 5 mm.

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

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

[0019] 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. 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 surfaces 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 components constituting the cell 1 will be described below.

[0021] The support substrate 2 has gas flow channels 2a therein 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 in 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] A generally known material can be used for the fuel electrode 5. The fuel electrode 5 is made of a porous conductive ceramic, such as calcium oxide, magnesium oxide, or ZrO in which a rare earth element oxide is solid-solved. ２and Ni and / or NiO may be used. The rare earth element oxide may contain, for example, a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or ZrO in which a rare earth element oxide is solid-solved may be used. ２ 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 fuel gas and oxygen-containing gas to occur.

[0025] The material of the solid electrolyte layer 6 is, for example, ZrO in which 3 mol % to 15 mol % of rare earth element oxide is dissolved. ２ The rare earth element oxide may contain, 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 be, for example, ZrO in which Y, Yb, Sc, or Gd is solid-solved. ２ and BaZrO in which Sc, Y or Yb is solid-solved. ３ The solid electrolyte layer 6 will be described in detail 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 (described later) to diffuse into the solid electrolyte layer 6, thereby preventing the solid electrolyte layer 6 from being filled with SrZrO ３ This makes it difficult for an electrically resistive layer to form.

[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 is, for example, cerium oxide (CeO) in which rare earth elements other than Ce (cerium) are dissolved. ２ ) may be included. As such a rare earth element, Gd (gadolinium), Sm (samarium), etc. may be used.

[0028] The air electrode 8 is gas permeable. 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 that is generally used for air electrodes. ３ The material may be a conductive ceramic such as a perovskite-type 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 O ３ , La ｘ Sr １－ｘ MnO ３ , La ｘ Sr １－ｘ FeO ３ , La ｘ Sr １－ｘ CoO ３ Here, x is 0<x<1, and y is 0<y<1.

[0031] Furthermore, the interconnector 4 is dense and makes it difficult for 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 to occur. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0032] The material of the interconnector 4 is a lanthanum chromite-based perovskite oxide (LaCrO ３ -based oxides), lanthanum strontium titanium-based perovskite-type oxides ((La,Sr)TiO ３ These materials are electrically conductive and are not easily reduced or oxidized even when in contact with fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air.

[0033] <Configuration of Electrochemical Cell Device> Next, an electrochemical cell device according to this embodiment using the above-described cell 1 will be described with reference to FIGS. 2A to 2C. FIG. 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. FIG. 2B is a cross-sectional view taken along line X-X shown in FIG. 2A. FIG. 2C is a top view showing an example of an 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 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 15 and a gas tank 16. The support 15 and the gas tank 16, which are the support member 14, are made of, for example, metal.

[0036] 2B, the support body 15 has insertion holes 15a into which the lower ends of the plurality of cells 1 are inserted. The lower ends of the plurality of cells 1 and the inner wall of the insertion holes 15a are joined with 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 recessed groove 16a located around the opening. The outer peripheral edge of the support 15 is joined to the gas tank 16 by a bonding material 21 filled in the recessed 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 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 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 a respective support 15. The gas tank 16 has two through-holes on its top surface. A respective support 15 is disposed in each through-hole. An internal space 22 is formed by one gas tank 16 and 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. For example, the width of the insertion hole 15a is greater than the length of the cell 1 in the width direction W (see FIG. 1A ).

[0042] 2B , a fixing material 13 is filled and solidified at the joint between the inner wall of the insertion hole 15a and the lower end of the cell 1. This bonds and fixes the inner wall of the insertion hole 15a to the lower end of each of the multiple cells 1, and also bonds and fixes the lower ends of the cells 1 to each other. The gas flow path 2a of each cell 1 communicates with the internal space 22 of the support member 14 at its lower end.

[0043] A material with low 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] Examples of the crystallized glass include SiO ２ -CaO system, MgO-B ２ O ３ System, La ２ O ３ -B ２ O ３ -MgO system, La ２ O ３ -B ２ O ３-ZnO-based, SiO ２ -CaO-ZnO system materials, etc., may be used, and in particular SiO ２ - MgO-based materials may also be used.

[0045] 2B , a connecting member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The connecting member 18 electrically connects the anode 5 of one adjacent cell 1 to the cathode 8 of the other cell 1 in series. More specifically, the connecting member 18 connects the interconnector 4 electrically connected to the anode 5 of one adjacent cell 1 to the cathode 8 of the other cell 1.

[0046] 2B, an end current collecting member 17 is electrically connected to the cell 1 positioned outermost in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive portion 19 that protrudes outside the cell stack 11. The conductive portion 19 collects electricity generated by power generation in the cells 1 and extracts it 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 and 11B are connected in series. In such a 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 terminal 19A is a positive electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the positive-side end current collecting member 17 of the cell stack 11A. The negative terminal 19B is a negative electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the negative-side end current collecting member 17 of the cell stack 11B.

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

[0050] <Details of Solid Electrolyte Layer> Next, details of the solid electrolyte layer 6 of the electrochemical cell 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 6 a and a second surface 6 b located at both ends in the thickness direction T. The first surface 6 a is in contact with the anode 5. The second surface 6 b is in contact with the intermediate layer 7.

[0052] The solid electrolyte layer 6 includes 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 plurality of electrolyte particles 61 include first particles 61a and second particles 61b. The first particles 61a have a particle diameter equal to or greater than 1 / 10 of the average thickness of the solid electrolyte layer 6. The second particles 61b have a particle diameter equal to or less than 1 / 10 of the average thickness of the solid electrolyte layer 6. That is, when the average thickness of the solid electrolyte layer 6 is t, the first particles 61a have a particle diameter equal to or greater than (1 / 10)t, and the second particles 61b have a particle diameter equal to or less than (1 / 10)t. In other words, the second particles 61b are electrolyte particles 61 having a particle diameter smaller than that of the first particles 61a. The particle diameter of the electrolyte particles 61 is a circle-equivalent diameter obtained by observing a cross section of the solid electrolyte layer 6. The average particle diameter of the second particles 61b may be equal to or less than 1 / 5 of the average particle diameter of the first particles 61a.

[0054] In the solid electrolyte layer 6, the plurality of electrolyte particles 61 include the first particles 61 a and the second particles 61 b, which, for example, reduces the likelihood of voids occurring between adjacent electrolyte particles 61. This improves the bending strength of the solid electrolyte layer 6 compared to, for example, a case in which the plurality of electrolyte particles 61 do not include the second particles 61 b. Furthermore, a cell 1 having such a solid electrolyte layer 6 improves, for example, performance.

[0055] Furthermore, in the cross section shown in FIG. 3 , i.e., in the cross section of the solid electrolyte layer 6 intersecting the first surface 6a and the second surface 6b, the second particles 61b may include second particles 61b that are in contact with two or more first particles 61a and surrounded by the two or more first particles 61a. This, for example, makes it easier to relieve stress generated inside the solid electrolyte layer 6, further improving the bending strength of the solid electrolyte layer 6. Furthermore, a cell 1 having such a solid electrolyte layer 6 may, for example, further improve performance. Hereinafter, a second particle 61b that is in contact with two or more first particles 61a and surrounded by the two or more first particles 61a will simply be referred to as a second particle 61b surrounded by two or more first particles 61a. The second particle 61b may be in contact with the first particle 61a via a grain boundary phase. In this case, the grain boundary phase may have a thickness equal to or less than the particle diameter of the second particle 61b.

[0056] 3, the second particles 61b surrounded by two or more first particles 61a may be two or less second particles 61b that are in contact with each other. This, for example, makes it less likely that ions will be impeded from moving in the thickness direction T inside the solid electrolyte layer 6, improving ion conductivity. Furthermore, a cell 1 having such a solid electrolyte layer 6 improves power generation performance, for example.

[0057] In addition, in the cross section of the solid electrolyte layer 6 shown in FIG. 3 , one or more first particles 61a may be located between the first surface 6a and the second particles 61b. Furthermore, one or more first particles 61a may be located between the second surface 6b and the second particles 61b. In other words, the solid electrolyte layer 6 may have one or more first particles 61a between the first surface 6a and the second surface 6b and the second particles 61b. Alternatively, the second particles 61b may not face the first surface 6a and the second surface 6b. In this manner, the solid electrolyte layer 6 has second particles 61b located away from the first surface 6a and the second surface 6b. In such a solid electrolyte layer 6, stress generated inside the solid electrolyte layer 6 is more easily alleviated compared to, for example, a case in which the solid electrolyte layer 6 does not have second particles 61b located away from the first surface 6a and the second surface 6b. As a result, the bending strength of the solid electrolyte layer 6 is improved. Furthermore, the cell 1 having such a solid electrolyte layer 6 has improved performance, for example.

[0058] Furthermore, the number of second particles 61b located away from the first surface 6a and the second surface 6b may be 90% or more of the plurality of electrolyte particles 61 included in the solid electrolyte layer 6. In this manner, the solid electrolyte layer 6 has a large number of second particles 61b located away from the first surface 6a and the second surface 6b, which, for example, makes it easier to relieve stress generated inside the solid electrolyte layer 6 and improves the bending strength of the solid electrolyte layer 6. Furthermore, a cell 1 including such a solid electrolyte layer 6 can, for example, improve performance.

[0059] 3, the plurality of electrolyte particles 61 in the solid electrolyte layer 6 may contain 20% or less of the second particles 61b by number. This makes it less likely that the movement of ions in the thickness direction T within the solid electrolyte layer 6 is hindered compared to when the plurality of electrolyte particles 61 contain more than 20% of the second particles 61b, thereby improving ion conductivity. Furthermore, a cell 1 having such a solid electrolyte layer 6 may, for example, improve power generation performance.

[0060] 3, the plurality of electrolyte particles 61 in the solid electrolyte layer 6 may contain 1% or more of the second particles 61b by number. This makes it easier to alleviate stress generated inside the solid electrolyte layer 6 compared to, for example, a case in which the plurality of electrolyte particles 61 contain less than 1% of the second particles 61b, thereby improving the bending strength of the solid electrolyte layer 6. Furthermore, a cell 1 having such a solid electrolyte layer 6 may, for example, improve performance.

[0061] 3, the solid electrolyte layer 6 may have a porosity of 1% or less. This, for example, makes it less likely to impede the movement of ions in the thickness direction T inside the solid electrolyte layer 6, improving ion conductivity. Furthermore, a cell 1 having such a solid electrolyte layer 6 may, for example, improve power generation performance.

[0062] 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. The arrangement and particle size of the multiple electrolyte particles 61 in the solid electrolyte layer 6 can be calculated based on the results of an electron backscatter diffraction (EBSD) analysis of a cross section of the solid electrolyte layer 6 intersecting the first surface 6 a and the second surface 6 b. Specifically, a cross-sectional photograph of the solid electrolyte layer 6 is taken with an SEM at a magnification of, for example, 5000 times, and the obtained cross-sectional photograph is subjected to image analysis to calculate the particle size of each of the electrolyte particles 61 located in a region between the first surface 6 a and the second surface 6 b that contains 200 or more electrolyte particles 61. The particle size of the electrolyte particles 61 is calculated by measuring the area of ​​the electrolyte particles 61 using, for example, image analysis software and converting the area into a circle-equivalent diameter.

[0063] <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 an example of a module according to the first embodiment. Fig. 4 shows a state in which the front and rear surfaces, which are parts 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.

[0064] 4, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container. A reformer 102 is disposed above the cell stack device 10.

[0065] The reformer 102 reforms raw fuel such as natural gas or kerosene to generate fuel gas, which is then supplied 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, a highly efficient reforming reaction.

[0066] The fuel gas produced in the reformer 102 is supplied to the gas flow channel 2 a of the cell 1 (see FIG. 1A) through the gas distribution pipe 20 , the gas tank 16 , and the support member 14 .

[0067] Furthermore, in the module 100 having the above-described configuration, the temperature inside the module 100 during normal power generation reaches approximately 500°C to 1000°C due to the combustion of gas and the power generation of the cells 1.

[0068] In such a module 100, as described above, the module 100 can be configured to house the cell stack device 10 having the cells 1 with improved performance, thereby making it possible to make the module 100 with improved performance.

[0069] <Module Enclosure Device> Fig. 5 is an exploded perspective view schematically illustrating an example of a module enclosure device according to the first embodiment. The module enclosure device 110 according to this embodiment includes an outer 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 outer case 111. Note that some components are omitted in Fig. 5.

[0070] 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 for operating the module 100. Note that in Fig. 5, the auxiliary equipment accommodated in the auxiliary equipment accommodating chamber 116 is omitted from the illustration.

[0071] The partition plate 114 also 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 that constitutes the module housing chamber 115 has an exhaust port 118 for exhausting air from within the module housing chamber 115.

[0072] In such a module accommodating device 110, as described above, the module 100 with improved performance is provided in the module accommodating chamber 115, so that the module accommodating device 110 can have improved performance.

[0073] In the above embodiment, a case where a hollow flat plate-type 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.

[0074] 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.

[0075] In the above-described embodiment, a so-called "vertical stripe type" electrochemical cell device 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 support 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 support substrate, and adjacent element units are electrically connected.

[0076] Fig. 6A is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. Fig. 6B is a transverse cross-sectional view showing an example of an electrochemical cell according to the second embodiment. Fig. 7 is an enlarged cross-sectional view of a region R2 shown in Fig. 6B.

[0077] 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 units 3 on a support substrate 2. A gas flow path 2a through which fuel gas flows from the pipe 22a is provided inside the support substrate 2.

[0078] The cells 1A are electrically connected to one another via connection members 31. The connection members 31 are located between the element portions 3 of the cells 1A, and connect the adjacent cells 1A to one another.

[0079] 6B , the cell 1A according to the second embodiment includes a support substrate 2, a pair of element units 3, and a sealing unit 30. The support substrate 2 is columnar and has a pair of opposing flat surfaces, a first flat surface n1 and a second flat surface n2, and a pair of arc-shaped side surfaces m connecting the first flat surface n1 and the second flat surface n2.

[0080] The pair of element portions 3 are located opposite each other on the first flat surface n1 and the second flat surface 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.

[0081] 7 , the solid electrolyte layer 6 has a first surface 6 a and a second surface 6 b located at both ends in the thickness direction T. The first surface 6 a is in contact with the anode 5. The second surface 6 b is in contact with the intermediate layer 7.

[0082] The solid electrolyte layer 6 has a plurality of electrolyte particles 61 separated by grain boundaries 60. Each of the plurality of electrolyte particles 61 includes an oxide.

[0083] The plurality of electrolyte particles 61 include first particles 61 a and second particles 61 b. The first particles 61 a are electrolyte particles 61 having a particle size that is 1 / 10 or more of the average thickness of the solid electrolyte layer 6. The second particles 61 b ​​are electrolyte particles 61 having a particle size that is smaller than the particle size of the first particles 61 a. In other words, when the average thickness of the solid electrolyte layer 6 is t, the first particles 61 a have a particle size that is (1 / 10)t or more, and the second particles 61 b ​​have a particle size that is less than (1 / 10)t.

[0084] In the solid electrolyte layer 6, the plurality of electrolyte particles 61 include the first particles 61 a and the second particles 61 b, which, for example, reduces the likelihood of voids occurring between adjacent electrolyte particles 61. This improves the bending strength of the solid electrolyte layer 6 compared to, for example, a case in which the plurality of electrolyte particles 61 do not include the second particles 61 b. Furthermore, a cell 1A having such a solid electrolyte layer 6 improves, for example, performance.

[0085] [Third Embodiment] Fig. 8 is a perspective view showing an example of an electrochemical cell according to a third embodiment, and Fig. 9 is a partial cross-sectional view showing the example of the electrochemical cell shown in Fig. 8.

[0086] 8 and 9 , the cell 1B includes an element portion 3B in which an anode 5, a solid electrolyte layer 6, an intermediate layer 7, and a cathode 8 are stacked, and conductive members 91 and 92. In an electrochemical cell device in which a plurality of flat cells are stacked, for example, the plurality of cells 1B are electrically connected by conductive members 91 and 92, which are adjacent metal layers. The conductive members 91 and 92 electrically connect adjacent cells 1B to each other and have gas flow paths for supplying gas to the anode 5 or the cathode 8.

[0087] 9, cell 1B has a sealing material that airtightly 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 and 95 that serve as a frame. The bonding material 93 may be glass or a metal material such as silver solder.

[0088] 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. Either or both of the support members 94, 95 may be made of an insulating material. If the support member 94 is made of metal, the support member 94 may be integrated with the conductive member 92. If the support member 95 is made of metal, the support member 95 may be integrated with the conductive member 91.

[0089] One of the support members 94 and 95 is insulating, and electrically insulates the two conductive members 91 and 92 that sandwich the flat cell from each other.

[0090] 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 located at both ends in the thickness direction T. First surface 6a is in contact with anode 5. Second surface 6b is in contact with intermediate layer 7.

[0091] The solid electrolyte layer 6 has a plurality of electrolyte particles 61 separated by grain boundaries 60. Each of the plurality of electrolyte particles 61 includes an oxide.

[0092] The plurality of electrolyte particles 61 include first particles 61 a and second particles 61 b. The first particles 61 a are electrolyte particles 61 having a particle size that is 1 / 10 or more of the average thickness of the solid electrolyte layer 6. The second particles 61 b ​​are electrolyte particles 61 having a particle size that is smaller than the particle size of the first particles 61 a. In other words, when the average thickness of the solid electrolyte layer 6 is t, the first particles 61 a have a particle size that is (1 / 10)t or more, and the second particles 61 b ​​have a particle size that is less than (1 / 10)t.

[0093] In the solid electrolyte layer 6, the plurality of electrolyte particles 61 include the first particles 61 a and the second particles 61 b, which, for example, reduces the likelihood of voids occurring between adjacent electrolyte particles 61. This improves the bending strength of the solid electrolyte layer 6 compared to, for example, a case in which the plurality of electrolyte particles 61 do not include the second particles 61 b. Furthermore, a cell 1B having such a solid electrolyte layer 6 improves, for example, performance.

[0094] [Fourth embodiment] Fig. 11A is a cross-sectional view showing an example of an electrochemical cell according to a 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 region R4 shown in Fig. 11A. Note that Fig. 12 can also be applied to the examples of Figs. 11B and 11C.

[0095] As shown in FIGS. 11A to 11C , the cell 1C includes an element section 3C, which is composed of a stack of an anode 5, a solid electrolyte layer 6, an intermediate layer 7, and a cathode 8, and a support substrate 2. The support substrate 2 has through-holes or pores in a portion in contact with the element section 3C, and also includes a member 120 located outside the gas flow path 2a. The support substrate 2 allows gas to flow 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 adjacent cells 1C. The element section 3C may be formed directly on the support substrate 2, or may be bonded to the support substrate 2 with a bonding material.

[0096] 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 insulating properties.

[0097] 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.

[0098] 12 , the solid electrolyte layer 6 has a first surface 6 a and a second surface 6 b located at both ends in the thickness direction T. The first surface 6 a is in contact with the anode 5. The second surface 6 b is in contact with the intermediate layer 7.

[0099] The solid electrolyte layer 6 has a plurality of electrolyte particles 61 separated by grain boundaries 60. Each of the plurality of electrolyte particles 61 includes an oxide.

[0100] The plurality of electrolyte particles 61 include first particles 61 a and second particles 61 b. The first particles 61 a are electrolyte particles 61 having a particle size that is 1 / 10 or more of the average thickness of the solid electrolyte layer 6. The second particles 61 b ​​are electrolyte particles 61 having a particle size that is smaller than the particle size of the first particles 61 a. In other words, when the average thickness of the solid electrolyte layer 6 is t, the first particles 61 a have a particle size that is (1 / 10)t or more, and the second particles 61 b ​​have a particle size that is less than (1 / 10)t.

[0101] In the solid electrolyte layer 6, the plurality of electrolyte particles 61 include the first particles 61 a and the second particles 61 b, which, for example, reduces the likelihood of voids occurring between adjacent electrolyte particles 61. This improves the bending strength of the solid electrolyte layer 6 compared to, for example, a case in which the plurality of electrolyte particles 61 do not include the second particles 61 b. Furthermore, a cell 1C having such a solid electrolyte layer 6 improves, for example, performance.

[0102] Other Embodiments Next, electrochemical cell devices according to other embodiments will be described.

[0103] In the above-described 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 an "electrochemical cell," "electrochemical cell device," "module," and "module housing device." However, 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 and a second electrode, and decomposes water vapor into hydrogen and oxygen, or decomposes carbon dioxide into carbon monoxide and oxygen, when supplied with electric power. Furthermore, in the above-described 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.

[0104] Samples Nos. 1 to 8 simulating the solid electrolyte layer 6 were prepared and their performance was evaluated.

[0105] (Preparation of Samples No. 1 to 8) Samples No. 1 to 8 were prepared using particulate electrolyte materials with different particle sizes. ２ O ３ ZrO in which 8 mol % is dissolved ２ Two types of material (YSZ material) were prepared. The two types of YSZ material were material A with an average particle size of 2 μm and material B with an average particle size of 0.5 μm. Two types of slurries were prepared using material A, material B, a solvent, and a dispersant. Slurry A was prepared by crushing material A together with the solvent and dispersant in a ball mill for 10 hours. Slurry B was prepared by crushing material B together with the solvent and dispersant in a ball mill for 0.5 hours. The crushing time for slurry B was shortened so that some particle agglomerations remained. The agglomerated particles of material B were not easily absorbed by the particles of material A even when mixed with material A and fired, and tended to remain as second particles 61b in the solid electrolyte layer 6.

[0106] Slurry A and Slurry B were mixed in the following ratios and dried to obtain mixed powders. The mixing ratios of Slurry A and Slurry B, expressed as the mass ratio (A:B) of material A to material B, were as follows: Samples Nos. 1 and 5 (100:0), Samples Nos. 2 and 6 (98:2), Samples Nos. 3 and 7 (97:3), and Samples Nos. 4 and 8 (95:5).

[0107] The prepared mixed powders were used to prepare test pieces (samples No. 1 to 4) for bending strength tests. The mixed powders were uniaxially pressed to prepare rectangular prism-shaped compacts. The obtained compacts were fired at 1500°C in air to prepare sintered bodies with different contents of the second particles 61b.

[0108] The resistance of the solid electrolyte layer 6 was evaluated by fabricating single cells (Samples Nos. 5 to 8) each having a solid electrolyte layer 6 using the above-described mixed powder, an anode 5, an intermediate layer 7, and an air electrode 8. A laminated sheet was formed by laminating a solid electrolyte sheet fabricated using the above-described mixed powder on an anode molded sheet. The laminated sheet was then degreased and fired in air at 1500°C to obtain a laminated sintered body. A slurry for an intermediate layer was applied to the solid electrolyte layer of the obtained laminated sintered body, followed by degreasing and firing in air at 1350°C. A slurry for an air electrode was further applied to the formed intermediate layer, followed by degreasing and firing in air at 1150°C to obtain single cells having solid electrolyte layers 6 with different contents of second particles 61b.

[0109] (Evaluation of Samples No. 1 to 4) For Samples No. 1 to 4, the average particle size of the first particles 61a, the average particle size of the second particles 61b, the content of the second particles 61b, and the bending strength of the solid electrolyte layer 6 were measured. FIG. 13 is a diagram showing the evaluation results for Samples No. 1 to 4. In FIG. 13, the content of the second particles 61b is the proportion of the number of second particles 61b among the electrolyte particles 61 in each of Samples No. 1 to 4 whose cross sections were observed. The bending strength was a four-point bending strength measured in accordance with JIS R 1601.

[0110] 13 , Samples No. 2 to 4, which included first particles 61 a and second particles 61 b, had higher bending strength than Sample No. 1, which included only first particles 61 a. Furthermore, in Samples No. 2 to 4, as the content of second particles 61 b ​​increased, the bending strength also increased.

[0111] (Evaluation of Samples No. 5 to 8) For Samples No. 5 to 8, the average particle size of the first particles 61a, the average particle size of the second particles 61b contained in the solid electrolyte layer 6, the content of the second particles 61b, and the resistance of the single cell were measured. FIG. 14 is a diagram showing the evaluation results for Samples No. 5 to 8. In FIG. 14, the content of the second particles 61b is the proportion of the number of second particles 61b among the electrolyte particles 61 in the solid electrolyte layer 6 of each of Samples No. 5 to 8, which was observed in cross section. The resistance is an ohmic resistance measured by an AC impedance method.

[0112] 14 , in Samples No. 6 to 8, which contained first particles 61 a and second particles 61 b, the resistance increased as the content of second particles 61 b ​​increased. Samples No. 6 to 7 had resistance equivalent to that of Sample No. 5, which contained only first particles 61 a. Furthermore, the resistance of Sample No. 8 increased compared to Sample No. 5, but to an extent that did not pose a problem in practical use.

[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 within the scope that does not deviate from the gist of the present disclosure.

[0114] In one embodiment, (1) the solid electrolyte layer has a plurality of electrolyte particles containing an oxide, and the plurality of electrolyte particles include first particles having a particle size that is 1 / 10 or more of an average thickness of the solid electrolyte layer, and second particles having a particle size that is smaller than that of the first particles.

[0115] (2) The solid electrolyte layer of (1) above may have a first surface and a second surface located at both ends in a thickness direction, and in a cross section intersecting the first surface and the second surface, the second particle may be in contact with two or more of the first particles and may include a second particle surrounded by the two or more first particles.

[0116] (3) In the solid electrolyte layer of (2) above, in a cross section intersecting the first surface and the second surface, the two or more first particles may surround two or less of the surrounded second particles that are in contact with each other.

[0117] (4) The solid electrolyte layer of any one of (1) to (3) above may have a first surface and a second surface located at both ends in a thickness direction, and one or more of the first particles may be located between the first surface and the second surface and the second particle in a cross section intersecting the first surface and the second surface.

[0118] (5) The solid electrolyte layer according to any one of (1) to (4) above may have a first surface and a second surface located at both ends in a thickness direction, and in a cross section intersecting the first surface and the second surface, the plurality of electrolyte particles may include 20% or less of the second particles by number.

[0119] (6) The solid electrolyte layer according to any one of (1) to (5) above may have a first surface and a second surface located at both ends in a thickness direction, and a porosity of 1% or less in a cross section intersecting the first surface and the second surface.

[0120] In one embodiment, (7) an electrochemical cell includes the solid electrolyte layer of any one of (1) to (6) above.

[0121] In one embodiment, the electrochemical cell device (8) has a cell stack including the electrochemical cell (7) described above.

[0122] In one embodiment, (9) a module includes the electrochemical cell device of (8) above, and a container that houses the electrochemical cell device.

[0123] In one embodiment, (10) a module housing device includes the module of (9) above, an auxiliary device for operating the module, and an exterior case for housing the module and the auxiliary device.

[0124] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0125] REFERENCE SIGNS LIST 1, 1A to 1C Cell 2 Support substrate 3 Element portion 4 Interconnector 5 Anode 6 Solid electrolyte layer 7 Intermediate layer 8 Cathode 10 Cell stack device 11 Cell stack 12 Fixing member 13 Fixing material 14 Support member 15 Support body 16 Gas tank 17 End current collecting member 18 Connection member 60 Grain boundary 61 Electrolyte particle 61a First particle 61b Second particle 100 Module 110 Module housing device

Claims

1. A solid electrolyte layer having a plurality of electrolyte particles including an oxide, The plurality of electrolyte particles include first particles having a particle size equal to or greater than 1 / 10 of the average thickness of the solid electrolyte layer; second particles having a particle size smaller than that of the first particles; a solid electrolyte layer comprising:

2. a first surface and a second surface located at both ends in a thickness direction; In a cross section intersecting the first surface and the second surface, the second particle includes a second particle that is in contact with two or more of the first particles and is surrounded by the two or more first particles. The solid electrolyte layer according to claim 1 .

3. In a cross section intersecting the first surface and the second surface, the two or more first particles surround two or less of the surrounded second particles that are in contact with each other. The solid electrolyte layer according to claim 2 .

4. a first surface and a second surface located at both ends in a thickness direction; In a cross section intersecting the first surface and the second surface, one or more of the first particles are located between the first surface and the second surface and the second particle. The solid electrolyte layer according to claim 1 .

5. a first surface and a second surface located at both ends in a thickness direction; In a cross section intersecting the first surface and the second surface, the plurality of electrolyte particles include the second particles in a number ratio of 20% or less. The solid electrolyte layer according to claim 1 .

6. a first surface and a second surface located at both ends in a thickness direction; The porosity is 1% or less in a cross section intersecting the first surface and the second surface. The solid electrolyte layer according to claim 1 .

7. An electrochemical cell comprising the solid electrolyte layer according to any one of claims 1 to 6.

8. A cell stack comprising the electrochemical cell of claim 7. Electrochemical cell apparatus.

9. The electrochemical cell device according to claim 8 ; a container for housing the electrochemical cell device; A module comprising:

10. A module according to claim 9; Auxiliary equipment for operating the module; an exterior case that houses the module and the auxiliary equipment; A module housing device comprising: