Electrochemical cell, electrochemical cell device, module, and module storage device

Abstract

This electrochemical cell comprises a first electrode layer, a second electrode layer, and a solid electrolyte layer. The solid electrolyte layer is positioned between the first electrode layer and the second electrode layer. The solid electrolyte layer contains a first element. The first electrode layer includes a second element the valency of which is less likely to vary than the first element.

Description

Electrochemical cell, electrochemical cell device, module, and module housing device

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

[0002] In recent years, various fuel cell stack devices having 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 2018-152200 A

[0004] An electrochemical cell according to one aspect of the embodiment includes a first electrode layer, a second electrode layer, and a solid electrolyte layer. The solid electrolyte layer is located between the first electrode layer and the second electrode layer. The solid electrolyte layer includes a first element. The first electrode layer includes a second element whose valence is less likely to change than the first element.

[0005] The electrochemical cell device of the present disclosure also includes a cell stack including the electrochemical cell described above.

[0006] The module of the present disclosure includes the electrochemical cell device described above and a container that houses the electrochemical cell device.

[0007] 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.

[0008] 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. 3A is an enlarged cross-sectional view of region R1 shown in FIG. 1A. FIG. 3B is a cross-sectional view showing another example of 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 included in the electrochemical cell device according to the second embodiment. FIG. 7 is an enlarged cross-sectional view of 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 of the electrochemical cell shown in Fig. 8. Fig. 10 is an enlarged cross-sectional view of a region R3 shown in Fig. 9. Fig. 11A is a transverse cross-sectional view showing an example of an electrochemical cell according to a fourth embodiment. Fig. 11B is a transverse cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment. Fig. 11C is a transverse cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment. Fig. 12 is an enlarged cross-sectional view of a region R4 shown in Fig. 11A.

[0009] In the above-described fuel cell stack device, there is a concern that power generation performance may be reduced.

[0010] Therefore, there is a need to provide electrochemical cells, electrochemical cell devices, modules, and module housing devices that are less likely to deteriorate in performance.

[0011] Hereinafter, embodiments of an electrochemical cell, an electrochemical cell device, a module, and a module housing device disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the disclosure is not limited to the embodiments described below.

[0012] 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.

[0013] 1A to 1C, electrochemical cells constituting an electrochemical cell device 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.

[0014] 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.

[0015] 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 of 5 cm to 50 cm in the length direction L and a length of 1 cm to 10 cm in the width direction W perpendicular to the length direction L. The thickness of the entire cell 1 in the thickness direction T may be, for example, 1 mm to 5 mm.

[0016] 1A, the cell 1 includes a conductive support substrate 2, an element portion 3, and an interconnector 4. The support substrate 2 is columnar, having a pair of opposing first and second surfaces n1 and n2, and a pair of arc-shaped side surfaces m connecting the first and second surfaces n1 and n2.

[0017] The element section 3 is provided on the first surface n1 of the support substrate 2. The element section 3 has an anode layer 5, a solid electrolyte layer 6, and an air cathode layer 8. In the example shown in FIG. 1A , an interconnector 4 is located on the second surface n2 of the cell 1. The cell 1 may also have an intermediate layer 7 between the solid electrolyte layer 6 and the air cathode layer 8.

[0018] 1B, the air electrode layer 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 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 arcuate side faces m of the cell 1. The interconnector 4 does not have to extend to the lower end of the cell 1.

[0019] Each of the components that make up the cell 1 will be described below.

[0020] 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, allowing the fuel gas flowing through the gas flow channels 2a to permeate to the fuel electrode layer 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.

[0021] 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.

[0022] The fuel electrode layer 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. ２Alternatively, ceramics containing an oxide having ion conductivity such as ZrO, and a metal having electronic conductivity such as Ni may be used. The rare earth element oxide may contain, for example, Y and / or Sc. Calcium oxide, magnesium oxide, or ZrO in which a rare earth element oxide is solid-solved may be used. ２ is sometimes referred to as stabilized zirconia. The stabilized zirconia may include partially stabilized zirconia. The conductive ceramic may be, for example, a ceramic containing an electrolyte material described below and Ni and / or NiO. The fuel electrode layer 5 is an example of a first electrode layer.

[0023] The open porosity of the fuel electrode layer 5 may be, for example, 15% or more, particularly in the range of 20% to 40%. The thickness of the fuel electrode layer 5 may be, for example, 1 μm to 30 μm. Details of the fuel electrode layer 5 will be described later.

[0024] The solid electrolyte layer 6 is an electrolyte and transfers ions between the fuel electrode layer 5 and the air electrode layer 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 solid electrolyte layer 6 has ion conductivity. The solid electrolyte layer 6 may contain, for example, Zr. The material of the solid electrolyte layer 6 is, for example, ZrO in which 3 mol % to 15 mol % of a rare earth element oxide is solid-dissolved. ２ The rare earth element oxide may contain, for example, one or more rare earth elements selected from Ce, Pr, Nd, Sm, Eu, Tb, Tm, and Yb. The material of the solid electrolyte layer 6 may be, for example, stabilized zirconia containing Yb. The material of the solid electrolyte layer 6 may be, for example, a ceria-based material in which Pr, Nd, Sm, Eu, Tb, Tm, or Yb is solid-solved. Details of the solid electrolyte layer 6 will be described later.

[0026] The air electrode layer 8 is gas permeable. The air electrode layer 8 is an example of a second electrode layer. The open porosity of the air electrode layer 8 may be in the range of, for example, 20% to 50%, and particularly 30% to 50%.

[0027] There are no particular restrictions on the material of the air electrode layer 8 as long as it is a material that is generally used for air electrodes. ３ Conductive ceramics such as perovskite oxides may also be used.

[0028] The material of the air electrode layer 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.

[0029] Furthermore, when the element section 3 has the intermediate layer 7, the intermediate layer 7 functions as a diffusion suppression layer. When elements such as Sr (strontium) contained in the air electrode layer 8 diffuse into the solid electrolyte layer 6, the solid electrolyte layer 6 is filled with, for example, SrZrO ３ The intermediate layer 7 is formed as a resistive layer by making it difficult for Sr to diffuse. ３ It makes it difficult for other oxides with electrical insulating properties to form.

[0030] The material of the intermediate layer 7 is not particularly limited as long as it generally prevents diffusion of elements between the air cathode layer 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. Examples of such rare earth elements include Gd (gadolinium) and Sm (samarium).

[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 (LaSrTiO ３ These materials are electrically 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. Alternatively, a metal or an alloy may be used as the material for the interconnector 4.

[0033] <Configuration of Electrochemical Cell Device> Next, an electrochemical cell device according to this embodiment using the above-described electrochemical cell will be described with reference to Figures 2A to 2C. Figure 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. Figure 2B is a cross-sectional view taken along line XX shown in Figure 2A. Figure 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 and are electrically conductive.

[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] In the example shown in FIG. 2A , the cell stack device 10 includes two rows of cell stacks 11, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 includes 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 its top surface. A support 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. Although FIG. 2A shows the cell stack device 10 having two rows of cell stacks 11, the cell stack device may have one row of cell stacks 11, or three or more rows of cell stacks 11.

[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, may be 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 may be 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-based, 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 conductive member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 electrically connects the anode layer 5 of one adjacent cell 1 to the air cathode layer 8 of the other cell 1 in series. More specifically, the conductive member 18 connects the interconnector 4 electrically connected to the anode layer 5 of one adjacent cell 1 to the air cathode layer 8 of the other cell 1. When the interconnector 4 is made of a metal or an alloy, the interconnector 4 and the conductive member 18 may be integrated, or the conductive member 18 may also serve as the interconnector 4.

[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 has two cell stacks 11A and 11B connected in series to function as a single battery. Therefore, 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 Element Unit> Next, the details of the fuel electrode layer 5 and the solid electrolyte layer 6 of the element unit 3 according to the first embodiment will be described with reference to Figures 3A and 3B. Figure 3A is an enlarged cross-sectional view of region R1 shown in Figure 1A.

[0051] 3A , the solid electrolyte layer 6 includes a first element 6 a. The first element 6 a may be, for example, a lanthanoid element having an electron in a 4f orbital. The first element 6 a may be, for example, one or more elements selected from Pr, Nd, Sm, Eu, Tb, Tm, and Yb.

[0052] The fuel electrode layer 5 includes a second element 5 a. The second element 5 a has a valence that is less likely to fluctuate than the first element 6 a. The second element 5 a may be, for example, one or more elements selected from Y, Sc, Mg, and Ca.

[0053] Here, "valence is not likely to fluctuate" means that valence is not likely to fluctuate, that is, the valence in a solid is stable at a certain value. For example, in a solid, the valence of Y and Sc is stable at 3+, and the valence of Mg and Ca is stable at 2+. In this way, by including the second element 5a, whose valence is less likely to fluctuate than the first element 6a, in the fuel electrode layer 5 under a reducing atmosphere, the ion conductivity is less likely to decrease compared to when the fuel electrode layer 5 contains the first element 6a. Therefore, the conductivity of the fuel electrode layer 5 is less likely to decrease, and a cell 1 is obtained in which the power generation performance is less likely to decrease.

[0054] The solid electrolyte layer 6 also includes an ionically conductive electrolyte material. The solid electrolyte layer 6 may include a metal oxide containing a first element 6a as the electrolyte material. The first element 6a may be solid-solved in the electrolyte material of the solid electrolyte layer 6. The electrolyte material of the solid electrolyte layer 6 may include Zr or Ce. The electrolyte material of the solid electrolyte layer 6 may be an oxide containing Zr or Ce. Lanthanoid elements having electrons in a 4f orbital have a small ionic radius. Oxygen vacancies are likely to occur in electrolyte materials in which such elements with a small ionic radius are solid-solved as the first element 6a. Electrolyte materials in which oxygen vacancies are likely to occur tend to exhibit high ionic conductivity. On the other hand, lanthanoid elements having electrons in a 4f orbital are prone to fluctuations in valence. In other words, such elements are prone to fluctuating between different valence states, for example, 2+ and 3+ valences, in a solid. Such elements are easily reduced in a reducing atmosphere.

[0055] The fuel electrode layer 5 contains an electrolyte material having ion conductivity. The fuel electrode layer 5 may contain a metal oxide containing a second element 5a as the electrolyte material. The second element 5a may be dissolved in the electrolyte material included in the fuel electrode layer 5. The electrolyte material included in the fuel electrode layer 5 may contain Zr. The electrolyte material included in the fuel electrode layer 5 may be an oxide containing Zr. The electrolyte material included in the fuel electrode layer 5 may be the same as or different from the electrolyte material included in the solid electrolyte layer 6. The second element 5a is less likely to be reduced than the first element 6a in a reducing atmosphere. Therefore, the electrolyte material in which the second element 5a is dissolved is less likely to have a reduced ion conductivity compared to the electrolyte material in which the first element 6a is dissolved even in a reducing atmosphere.

[0056] Further, the fuel electrode layer 5 may further contain catalyst particles 5b containing a metal. The catalyst particles 5b may be, for example, Ni and / or NiO.

[0057] FIG. 3B is a cross-sectional view showing another example of the region R1 shown in FIG. 1A. As shown in FIG. 3B, the fuel electrode layer 5 may further contain a first element 6a. Thereby, the bonding strength between the solid electrolyte layer 6 containing the first element 6a and the fuel electrode layer 5 is improved.

[0058] Further, the solid electrolyte layer 6 may further contain a second element 5a. Thereby, the bonding strength between the fuel electrode layer 5 containing the second element 5a and the solid electrolyte layer 6 is improved.

[0059] Furthermore, when the anode layer 5 contains the first element 6a, the solid electrolyte layer 6 may have a higher content of the first element 6a than the anode layer 5. This prevents degradation of power generation performance even when the anode layer 5 contains the first element 6a. When the anode layer 5 and / or the solid electrolyte layer 6 contain multiple first elements 6a, the content of the first elements 6a refers to the total content of the multiple first elements 6a. The content of the first element 6a refers to the molar ratio (mol %) of the first element 6a, calculated as an oxide, relative to the total oxide-equivalent of the elements contained in the anode layer 5 and the solid electrolyte layer 6 at a given location. The content of the first element 6a in each of the anode layer 5 and the solid electrolyte layer 6 can be confirmed by elemental analysis using, for example, EPMA. Specifically, a cross-sectional image including the anode layer 5 and the solid electrolyte layer 6 is captured. The elements contained in the anode layer 5 and the solid electrolyte layer 6 are analyzed in the captured cross-sectional image. From the obtained elemental analysis results, the average content (molar ratio) of the first element 6a in each portion can be calculated and compared. The elements contained in the fuel electrode layer 5 and the solid electrolyte layer 6 are elements detected from the electrolyte material contained in predetermined portions of the fuel electrode layer 5 and the solid electrolyte layer 6. In other words, when comparing the content of the first element 6a in each portion, the content of the first element 6a in the remaining elements excluding the catalyst particles 5b contained in the fuel electrode layer 5 can be compared.

[0060] Furthermore, when the solid electrolyte layer 6 contains the second element 5a, the solid electrolyte layer 6 may contain the second element 5a in the vicinity of a surface 61 (first surface) facing the fuel electrode layer 5. This improves the bonding strength between the fuel electrode layer 5 and the solid electrolyte layer 6. Here, "vicinity of surface 61" refers to a portion closer to surface 61 than to surface 62, when surface 61 of the solid electrolyte layer 6 facing the fuel electrode layer 5 and surface 62 of the solid electrolyte layer 6 located opposite surface 61 are defined.

[0061] Furthermore, when the fuel electrode layer 5 contains the first element 6a, the fuel electrode layer 5 may contain the first element 6a in the vicinity of a surface 51 (second surface) facing the solid electrolyte layer 6. This improves the bonding strength between the fuel electrode layer 5 and the solid electrolyte layer 6. Here, "vicinity of surface 51" refers to a portion closer to surface 51 than to surface 52, when surface 51 of the fuel electrode layer 5 facing the solid electrolyte layer 6 and surface 52 of the fuel electrode layer 5 located opposite surface 51 are defined.

[0062] Furthermore, when the anode layer 5 contains the first element 6a, the anode layer 5 may contain the first element 6a only in the vicinity of the surface 51 (second surface) facing the solid electrolyte layer 6. Since the conductivity of the anode layer 5 is less likely to decrease, a cell 1 is obtained in which the power generation performance is less likely to decrease, and the bonding strength between the anode layer 5 and the solid electrolyte layer 6 is improved.

[0063] <Module> Next, a module according to this embodiment 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 taken out to the rear.

[0064] 4, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container 101. 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, by accommodating the cell stack device 10 whose power generation performance is unlikely to deteriorate, the module 100 can be made to be one whose power generation performance is unlikely to deteriorate.

[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 accommodating chamber 115 is provided with a module 100 whose power generation performance is unlikely to deteriorate, thereby making it possible to provide a module accommodating device 110 whose power generation performance is unlikely to deteriorate.

[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" is exemplified in which only one element unit including a fuel electrode layer, a solid electrolyte layer, and an air electrode layer 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] 6A and 6B are cross-sectional views showing an example of an electrochemical cell device according to the second embodiment, and a transverse cross-sectional view showing an example of an electrochemical cell included in the electrochemical cell device according to the second embodiment.

[0077] 6A , in a cell stack device 10A according to this embodiment, multiple cells 1A extend in a longitudinal direction L from a pipe 22a through which fuel gas flows. Each cell 1A has multiple 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 connecting members 31. The connecting members 31 are located between the element units 3 of the cells 1A, and connect the adjacent cells 1A. Specifically, the connecting members 31 electrically connect the air electrode layer 8 of the element unit 3 of one of the adjacent cells 1A to the fuel electrode layer 5 of the element unit 3 of the other cell 1A.

[0079] 6B, the cell 1A 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 surface n1 and a second surface n2, and a pair of arc-shaped side surfaces m connecting the first surface n1 and the second surface n2.

[0080] The pair of element portions 3 are located opposite each other on the first surface n1 and the second 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 is an enlarged cross-sectional view of region R2 shown in FIG. 6B. Solid electrolyte layer 6 includes first element 6a. Fuel electrode layer 5 includes second element 5a whose valence is less likely to fluctuate than that of first element 6a. Fuel electrode layer 5 may further include catalyst particles 5b containing a metal.

[0082] In this way, since the fuel electrode layer 5 contains the second element 5a, whose valence is less likely to fluctuate than the first element 6a, the ionic conductivity is less likely to decrease compared to when the fuel electrode layer 5 under a reducing atmosphere contains the first element 6a. Therefore, the electrical conductivity of the fuel electrode layer 5 is less likely to decrease, and the cell 1A is obtained in which the power generation performance is less likely to decrease.

[0083] [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 of the electrochemical cell shown in Fig. 8 .

[0084] 8 and 9 , cell 1B has an element portion 3B in which an anode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air cathode layer 8 are stacked. In element portion 3B, the solid electrolyte layer 6 is sandwiched between the anode layer 5 and the air cathode layer 8. 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, 92, which are adjacent metal layers. The conductive members 91, 92 electrically connect adjacent cells 1B and have gas flow paths for supplying gas to the anode layer 5 or the air cathode layer 8.

[0085] 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 cell 1B, 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.

[0086] 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.

[0087] 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.

[0088] Figure 10 is an enlarged cross-sectional view of region R3 shown in Figure 9. Solid electrolyte layer 6 contains a first element 6a. Fuel electrode layer 5 contains a second element 5a whose valence is less likely to fluctuate than that of first element 6a. Fuel electrode layer 5 may further contain catalyst particles 5b containing a metal.

[0089] In this way, the fuel electrode layer 5 contains the second element 5a, whose valence is less likely to fluctuate than the first element 6a, so that the ionic conductivity is less likely to decrease compared to when the fuel electrode layer 5 in a reducing atmosphere contains the first element 6a. Therefore, the electrical conductivity of the fuel electrode layer 5 is less likely to decrease, and thus the cell 1B is obtained in which the power generation performance is less likely to decrease.

[0090] [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.

[0091] As shown in FIGS. 11A to 11C , the cell 1C includes an element section 3C, which is composed of a stack of an anode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air cathode layer 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.

[0092] 11A, the side surfaces of the anode layer 5 are 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 surfaces of the anode layer 5 may be covered and sealed with a sealant 9 made of dense glass or ceramic. The sealant 9 covering the side surfaces of the anode layer 5 may have electrical insulating properties.

[0093] 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.

[0094] 12 is an enlarged cross-sectional view of region R4 shown in FIG. 11A. Solid electrolyte layer 6 includes first element 6a. Fuel electrode layer 5 includes second element 5a whose valence is less likely to fluctuate than that of first element 6a. Fuel electrode layer 5 may further include catalyst particles 5b containing a metal.

[0095] In this way, the fuel electrode layer 5 contains the second element 5a, whose valence is less likely to fluctuate than the first element 6a, so that the ionic conductivity is less likely to decrease compared to when the fuel electrode layer 5 in a reducing atmosphere contains the first element 6a. Therefore, the electrical conductivity of the fuel electrode layer 5 is less likely to decrease, and a cell 1C is obtained in which the power generation performance is less likely to decrease.

[0096] Other Embodiments Next, electrochemical cell devices according to other embodiments will be described.

[0097] In the above-described embodiments, a 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 an 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. 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 electrolysis performance.

[0098] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the present disclosure. For example, instead of regions R2 to R4 shown in Figures 7, 10, and 12, an embodiment corresponding to region R1 shown in Figure 3B may be adopted.

[0099] In one embodiment, (1) an electrochemical cell includes: a first electrode layer; a second electrode layer; and a solid electrolyte layer located between the first electrode layer and the second electrode layer, wherein the solid electrolyte layer includes a first element; and the first electrode layer includes a second element whose valence is less likely to fluctuate than that of the first element.

[0100] (2) In the electrochemical cell of (1) above, the first electrode layer may contain the first element, and the solid electrolyte layer may have a larger content of the first element than the first electrode layer.

[0101] (3) In the electrochemical cell of (1) or (2) above, the first electrode layer may further include catalyst particles containing a metal.

[0102] (4) In the electrochemical cell of any one of (1) to (3) above, the first electrode layer and the solid electrolyte layer may contain an electrolyte material having ion conductivity, and the first element and the second element may be solid-solved in the electrolyte material.

[0103] (5) In the electrochemical cell of (4) above, the electrolyte material may contain Zr or Ce.

[0104] (6) In the electrochemical cell of any one of (1) to (5) above, the first element may be one or more elements selected from Pr, Nd, Sm, Eu, Tb, Tm, and Yb.

[0105] (7) In the electrochemical cell of any one of (1) to (6) above, the second element may be one or more elements selected from the group consisting of Y, Sc, Mg, and Ca.

[0106] (8) In the electrochemical cell of any one of (1) to (7) above, the solid electrolyte layer may contain the second element near a first surface facing the first electrode layer.

[0107] (9) In the electrochemical cell of any one of (1) to (8) above, the first electrode layer may contain the first element in the vicinity of a second surface facing the solid electrolyte layer.

[0108] (10) In the electrochemical cell of (9) above, the first electrode layer may contain the first element only in the vicinity of the second surface.

[0109] In one embodiment, (11) an electrochemical cell device has a cell stack including any one of the electrochemical cells (1) to (10) above.

[0110] In one embodiment, (12) a module includes the electrochemical cell device of (11) above, and a container that houses the electrochemical cell device.

[0111] In one embodiment, (13) a module housing device includes: the module of (12); an auxiliary device for operating the module; and an exterior case for housing the module and the auxiliary device.

[0112] 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.

[0113] REFERENCE SIGNS LIST 1 cell 2 support substrate 5 fuel electrode layer 5a second element 6 solid electrolyte layer 6a first element 7 intermediate layer 8 air electrode layer 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 conductive member 100 module 110 module accommodating device

Claims

1. a first electrode layer; A second electrode layer; a solid electrolyte layer located between the first electrode layer and the second electrode layer; Equipped with the solid electrolyte layer contains a first element, The first electrode layer contains a second element whose valence is less likely to change than the first element. Electrochemical cell.

2. the first electrode layer contains the first element, The solid electrolyte layer has a higher content of the first element than the first electrode layer.

10. The electrochemical cell of claim 1.

3. The first electrode layer further includes catalyst particles containing a metal.

10. The electrochemical cell of claim 1.

4. the first electrode layer and the solid electrolyte layer contain an electrolyte material having ion conductivity; The first element and the second element are dissolved in the electrolyte material.

10. The electrochemical cell of claim 1.

5. The electrolyte material contains Zr or Ce.

5. The electrochemical cell of claim 4.

6. The first element is one or more elements selected from Pr, Nd, Sm, Eu, Tb, Tm, and Yb.

10. The electrochemical cell of claim 1.

7. The second element is one or more elements selected from Y, Sc, Mg, and Ca.

10. The electrochemical cell of claim 1.

8. the solid electrolyte layer contains the second element in the vicinity of a first surface facing the first electrode layer; 10. The electrochemical cell of claim 1.

9. The first electrode layer includes the first element in the vicinity of a second surface facing the solid electrolyte layer.

10. The electrochemical cell of claim 1.

10. the first electrode layer contains the first element only in the vicinity of the second surface; 10. The electrochemical cell of claim 9.

11. A cell stack including the electrochemical cell according to any one of claims 1 to 10. Electrochemical cell apparatus.

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

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