Electrochemical cell, electrochemical cell device, module, and module accommodation device

Abstract

This electrochemical cell comprises a solid electrolyte layer and a first electrode. The first electrode includes a first dopant and CeO2. The first electrode has a first portion and a second portion located between the first portion and the solid electrolyte layer. In the second portion, the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce is larger than that in the first portion.

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 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] Japanese Patent Application Laid-Open No. 2003-272639

[0004] An electrochemical cell according to one aspect of the embodiment includes a solid electrolyte layer and a first electrode. The first electrode includes a first dopant and CeO. ２ The first electrode has a first portion and a second portion located between the first portion and the solid electrolyte layer, wherein the ratio of the concentration of the first dopant in the second portion to the total concentration of the first dopant and Ce is greater than that in the first portion.

[0005] An electrochemical cell according to one aspect of the embodiment includes a solid electrolyte layer and a first electrode. The first electrode includes a first dopant and CeO. ２ The first electrode has a first surface located opposite the solid electrolyte layer and a second surface in contact with the solid electrolyte layer, wherein the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce gradually decreases from the second surface to the first surface.

[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 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 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 transverse cross-sectional view showing an example of an electrochemical cell according to the 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 region R4 shown in Fig. 11A. Fig. 13 is an enlarged cross-sectional view of a portion of a transverse cross-sectional view showing another example of an electrochemical cell according to the first embodiment.

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

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

[0012] 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.

[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 portion 3, and an interconnector 4. The support substrate 2 may be columnar, having a pair of opposing flat surfaces, faces n1 and n2, and a pair of arc-shaped side faces m connecting faces n1 and n2.

[0018] The element section 3 is located on the 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 face n1. As shown in FIG. 1C, the interconnector 4 may extend to the lower end of the cell 1. At the lower end of the cell 1, the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. As shown in FIG. 1A, the solid electrolyte layer 6 is exposed on the surface of a pair of arc-shaped side faces m of the cell 1. The interconnector 4 does not have to extend to the lower end of the cell 1.

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

[0021] The support substrate 2 has gas flow channels 2a therein through which gas flows. FIG. 1A illustrates a support substrate 2 having six gas flow channels 2a as an example. The support substrate 2 has gas permeability, allowing the fuel gas flowing through the gas flow channels 2a to permeate to the anode 5. The support substrate 2 may be conductive. The conductive support substrate 2 collects electricity generated in the element section 3 to the interconnector 4.

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

[0023] The anode 5 is gas permeable and may have a porosity in the range of, for example, 30% to 50%, particularly 35% to 45%.

[0024] The fuel electrode 5 is made of a porous conductive ceramic, for example, cerium oxide (CeO ２ Alternatively, ceramics containing Ni and / or NiO may be used. Details of the anode 5 will be described later.

[0025] 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.

[0026] 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 may include:

[0027] The intermediate layer 7 functions as a diffusion suppression layer. The intermediate layer 7 makes it difficult for elements such as Sr (strontium) contained in the air electrode 8 (described later) to diffuse into the solid electrolyte layer 6, thereby preventing the solid electrolyte layer 6 from being filled with SrZrO ３ This makes it difficult for an electrically resistive layer such as the above to form.

[0028] 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.

[0029] The cathode 8 is gas permeable. The porosity of the cathode 8 may be, for example, 20% or more, and particularly in the range of 30% to 50%.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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 fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air.

[0034] <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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The shape of the insertion hole 15a may be, 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 ).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The positive electrode terminal 19A is a positive electrode when the power generated by the cell stack 11 is output to the outside. The positive electrode terminal 19A is electrically connected to the end current collector 17 on the positive electrode side of the cell stack 11A. The negative electrode terminal 19B is a negative electrode when the power generated by the cell stack 11 is output to the outside. The negative electrode terminal 19B is electrically connected to the end current collector 17 on the negative electrode side of the cell stack 11B.

[0050] 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.

[0051] <Details of Electrochemical Cell> Next, details of the electrochemical cell according to this embodiment will be described with reference to Fig. 3. Fig. 3 is an enlarged cross-sectional view of region R1 shown in Fig. 1A.

[0052] 3 , the fuel electrode 5 as a first electrode has a first surface 5f1 and a second surface 5f2 located at both ends in the thickness direction T. The first surface 5f1 is located on the opposite side of the solid electrolyte layer 6. The second surface 5f2 is located on the opposite side of the first surface 5f1 and is in contact with the solid electrolyte layer 6. The first surface 5f1 may be in contact with the support substrate 2.

[0053] The fuel electrode 5 is composed of a first dopant and CeO ２The first dopant may be, for example, Gd. The first dopant may be, for example, Sm, Y, La, Pr, or Yb. Ce is not included in the first dopant. CeO ２ exhibits ionic conductivity and electronic conductivity under a reducing atmosphere such as a hydrogen-containing gas. ２ Even when only the metal is included, it functions as an electrode.

[0054] The anode 5 has a first portion 51 and a second portion 52. The first portion 51 is located so as to include the first surface 5f1. The second portion 52 is located between the first portion 51 and the solid electrolyte layer 6, and the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce is higher in the first portion 51. For example, when the anode 5 is divided into three equal parts in the thickness direction T, the region including the first surface 5f1 may be defined as the first portion 51, and the region in contact with the solid electrolyte layer 6 and including the second surface 5f2 may be defined as the second portion 52.

[0055] CeO with a dopant solid solution amount of 30 atomic % or less ２ It is known that the ionic conductivity is low in a region where the amount of the dopant dissolved in solid solution is small, and the ionic conductivity is high in a region where the amount of the dopant dissolved in solid solution is large. ２ The ratio of the first dopant concentration to the first dopant concentration in the second portion 52 is approximately proportional to the amount of the first dopant dissolved in the first portion 52. The anode 5 is located between the first portion 51 and the solid electrolyte layer 6, and has the second portion 52 in which the ratio of the first dopant concentration is greater than that in the first portion 51. This increases the ionic conductivity in the second portion 52, which is closer to the solid electrolyte layer 6. Therefore, the electrode reaction is promoted in the cell 1 in which the anode 5 has the second portion 52, compared to the cell 1 in which the anode 5 does not have the second portion 52.

[0056] In addition, CeO, which has a small amount of dopant dissolved therein, ２ Therefore, when the anode 5 is located between the second portion 52 and the support substrate 2 and has the first portion 51 in which the Ce concentration ratio is higher than that in the second portion 52, the electron conductivity in the first portion 51 closer to the support substrate 2 becomes high. As a result, the cell 1 in which the anode 5 has the first portion 51 has improved cell performance compared to a cell in which the anode 5 does not have the first portion 51.

[0057] Furthermore, in second portion 52, the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce may be 1.5% or more, or even 2% or more, higher than the ratio of the first dopant in first portion 51. Furthermore, second portion 52 may have an average thickness of, for example, 2.5 μm or more, particularly 2.5 μm or more and 10 μm or less. Second portion 52 may be located so as to include the entire second surface 5f2, or may be located so as to include a portion of second surface 5f2.

[0058] In the first portion 51, for example, the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce may be 1 atomic % or more and 28 atomic % or less, and the ratio of the concentration of Ce to the total concentration of the first dopant and Ce may be 72 atomic % or more and 99 atomic % or less. In addition, in the second portion 52, for example, the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce may be 2.5 atomic % or more and 30 atomic % or less, and the ratio of the concentration of Ce to the total concentration of the first dopant and Ce may be 70 atomic % or more and 97.5 atomic % or less.

[0059] The anode 5 may include first particles 5a and second particles 5b. The first particles 5a may include a first dopant and CeO. ２ The second particles 5b have electronic conductivity and catalytic activity. The fuel electrode 5 includes the first particles 5a and the second particles 5b having catalytic activity, thereby improving the cell performance.

[0060] Here, the concentrations (atomic %) of Ce and the first dopant in each portion of the fuel electrode 5 can be confirmed by, for example, cutting or scraping each portion from the cell 1 and performing elemental analysis such as ICP optical emission spectroscopy. Furthermore, whether or not a specific element is present in a specific portion of each member can be determined by cross-sectional elemental analysis, such as specific element mapping, using a scanning electron microscope (SEM), transmission electron microscope (TEM), scanning transmission electron microscope (STEM), electron probe microanalyzer (EPMA), wavelength dispersive X-ray spectroscopy (WDS), or energy dispersive X-ray spectroscopy (EDS). The concentrations of Ce and the first dopant may be measured, for example, at three or more locations in each portion of the fuel electrode 5, and the average values ​​of the obtained concentrations may be compared.

[0061] <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.

[0062] 4, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container. A reformer 102 may be disposed above the cell stack device 10.

[0063] 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.

[0064] 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 .

[0065] 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.

[0066] In such a module 100, as described above, the module 100 is configured to house a cell stack device 10 having cells 1 that improve cell performance, thereby making it possible to create a module 100 with improved power generation performance.

[0067] <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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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 an electrochemical cell device that uses a cylindrical support substrate.

[0072] 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.

[0073] In the above-described embodiment, a vertically striped electrochemical cell device is illustrated in which so-called "vertically striped" electrochemical cells, each having only one element unit including a fuel electrode, a solid electrolyte layer, and an air electrode, are arranged on the surface of a support substrate. However, the present invention can also be applied to a horizontally striped electrochemical cell device in which so-called "horizontally striped" 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.

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

[0075] 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.

[0076] 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.

[0077] 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 may be columnar, having a pair of opposing flat surfaces, namely, surfaces n1 and n2, and a pair of arc-shaped side surfaces m connecting the surfaces n1 and n2.

[0078] The pair of element portions 3 are located opposite each other on the surfaces n1 and 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.

[0079] 7 , the fuel electrode 5 as a first electrode has a first surface 5f1 and a second surface 5f2 located at both ends in the thickness direction T. The first surface 5f1 is located on the opposite side of the solid electrolyte layer 6. The second surface 5f2 is located on the opposite side of the first surface 5f1 and is in contact with the solid electrolyte layer 6. The first surface 5f1 may be in contact with the support substrate 2.

[0080] The fuel electrode 5 is composed of a first dopant and CeO ２ The first dopant may be, for example, Gd. The first dopant may be, for example, Sm, Y, La, Pr, or Yb. Ce is not included in the first dopant.

[0081] The anode 5 has a first portion 51 and a second portion 52. The first portion 51 is located so as to include the first surface 5f1. The second portion 52 is located between the first portion 51 and the solid electrolyte layer 6, and the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce is greater in the first portion 51.

[0082] The anode 5 is located between the first portion 51 and the solid electrolyte layer 6, and has the second portion 52 in which the ratio of the concentration of the first dopant is greater than that in the first portion 51. This increases the ionic conductivity in the second portion 52, which is closer to the solid electrolyte layer 6. Therefore, the electrode reaction in the cell 1A in which the anode 5 has the second portion 52 is promoted compared to when the anode 5 does not have the second portion 52.

[0083] Furthermore, the anode 5 is located between the second portion 52 and the support substrate 2, and has the first portion 51 in which the Ce concentration ratio is greater than that in the second portion 52. This increases the electronic conductivity in the first portion 51, which is closer to the support substrate 2. Therefore, the cell 1A in which the anode 5 has the first portion 51 has improved cell performance compared to a cell without the first portion 51.

[0084] The anode 5 may include first particles 5a and second particles 5b. The first particles 5a may include a first dopant and CeO. ２ The second particles 5b have electronic conductivity and catalytic activity. In this way, the fuel electrode 5 includes the first particles 5a and the second particles 5b, thereby improving the cell 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 of the electrochemical cell shown in Fig. 8 .

[0086] 8 and 9 , cell 1B has an element section 3B in which an anode 5, a solid electrolyte layer 6, and a cathode 8 are stacked, and conductive members 91 and 92. The element section 3B may have an intermediate layer 7 located between the solid electrolyte layer 6 and the cathode 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 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 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.

[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. When the support member 94 is made of metal, the support member 94 may be integrated with the conductive member 92. When 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. In the cross section shown in Fig. 10, the fuel electrode 5 serving as the first electrode has a first surface 5f1 and a second surface 5f2 located at both ends in the thickness direction T. The first surface 5f1 is located on the opposite side of the solid electrolyte layer 6. The second surface 5f2 is located on the opposite side of the first surface 5f1 and is in contact with the solid electrolyte layer 6. The first surface 5f1 may be in contact with a conductive member 91.

[0091] The fuel electrode 5 is composed of a first dopant and CeO ２ The first dopant may be, for example, Gd. The first dopant may be, for example, Sm, Y, La, Pr, or Yb. Ce is not included in the first dopant.

[0092] The anode 5 has a first portion 51 and a second portion 52. The first portion 51 is located so as to include the first surface 5f1. The second portion 52 is located between the first portion 51 and the solid electrolyte layer 6, and the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce is greater in the first portion 51.

[0093] The anode 5 is located between the first portion 51 and the solid electrolyte layer 6, and has the second portion 52 in which the ratio of the concentration of the first dopant is greater than that in the first portion 51. This increases the ionic conductivity in the second portion 52, which is closer to the solid electrolyte layer 6. Therefore, the electrode reaction in the cell 1B in which the anode 5 has the second portion 52 is promoted compared to when the anode 5 does not have the second portion 52.

[0094] Furthermore, the anode 5 is located between the second portion 52 and the conductive member 91, and has the first portion 51 in which the Ce concentration ratio is greater than that in the second portion 52. This increases the electronic conductivity in the first portion 51, which is closer to the conductive member 91. Therefore, the cell 1B in which the anode 5 has the first portion 51 has improved cell performance compared to a cell without the first portion 51.

[0095] The anode 5 may include first particles 5a and second particles 5b. The first particles 5a may include a first dopant and CeO. ２ The second particles 5b have electronic conductivity and catalytic activity. In this way, the fuel electrode 5 includes the first particles 5a and the second particles 5b, thereby improving the cell performance.

[0096] [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 cross-sectional view of region R4 shown in Fig. 11A. Note that Fig. 12 can also be applied to the examples of Figs. 11B and 11C.

[0097] As shown in FIGS. 11A to 11C , the cell 1C includes an element section 3C, which includes a stack of an anode 5, a solid electrolyte layer 6, 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 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 metal plates may contain chromium. The metal plates 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. The element section 3C may also include an intermediate layer 7 located between the solid electrolyte layer 6 and the cathode 8.

[0098] 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.

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

[0100] 12 , the fuel electrode 5 serving as the first electrode has a first surface 5f1 and a second surface 5f2 located at both ends in the thickness direction T. The first surface 5f1 is located on the opposite side of the solid electrolyte layer 6. The second surface 5f2 is located on the opposite side of the first surface 5f1 and is in contact with the solid electrolyte layer 6. The first surface 5f1 may be in contact with the support substrate 2.

[0101] The fuel electrode 5 is composed of a first dopant and CeO ２ The first dopant may be, for example, Gd. The first dopant may be, for example, Sm, Y, La, Pr, or Yb. Ce is not included in the first dopant.

[0102] The anode 5 has a first portion 51 and a second portion 52. The first portion 51 is located so as to include the first surface 5f1. The second portion 52 is located between the first portion 51 and the solid electrolyte layer 6, and the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce is greater in the first portion 51.

[0103] The anode 5 is located between the first portion 51 and the solid electrolyte layer 6, and has the second portion 52 in which the concentration ratio of the first dopant is greater than that in the first portion 51. This increases the ionic conductivity in the second portion 52, which is closer to the solid electrolyte layer 6. Therefore, the electrode reaction in the cell 1C in which the anode 5 has the second portion 52 is promoted compared to when the anode 5 does not have the second portion 52.

[0104] Furthermore, the anode 5 is located between the second portion 52 and the support substrate 2, and has the first portion 51 in which the Ce concentration ratio is greater than that in the second portion 52. This increases the electronic conductivity in the first portion 51, which is closer to the support substrate 2. Therefore, the cell 1C in which the anode 5 has the first portion 51 has improved cell performance compared to a cell without the first portion 51.

[0105] The anode 5 may include first particles 5a and second particles 5b. The first particles 5a may include a first dopant and CeO. ２ The second particles 5b have electronic conductivity and catalytic activity. In this way, the fuel electrode 5 includes the first particles 5a and the second particles 5b, thereby improving the cell performance.

[0106] 13 is a cross-sectional view showing an enlarged portion of a cross-sectional view illustrating another example of the electrochemical cell according to the first embodiment.

[0107] 13 , the fuel electrode 5 as a first electrode has a first surface 5f1 and a second surface 5f2 located at both ends in the thickness direction T. The first surface 5f1 is located on the opposite side of the solid electrolyte layer 6. The second surface 5f2 is located on the opposite side of the first surface 5f1 and is in contact with the solid electrolyte layer 6. The first surface 5f1 may be in contact with the support substrate 2.

[0108] The fuel electrode 5 is composed of a first dopant and CeO ２ The first dopant may be, for example, Gd. The first dopant may be, for example, Sm, Y, La, Pr, or Yb. Ce is not included in the first dopant.

[0109] In the anode 5, the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce gradually decreases from the second surface 5f2 to the first surface 5f1. This gradual decrease in the ratio of the concentration of the first dopant from the second surface 5f2 to the first surface 5f1 increases ionic conductivity on the second surface 5f2 side and electronic conductivity on the first surface 5f1 side, thereby improving the performance of the cell 1.

[0110] The anode 5 may include first particles 5a and second particles 5b. The first particles 5a may include a first dopant and CeO. ２ The second particles 5b have electronic conductivity and catalytic activity. In this way, the fuel electrode 5 includes the first particles 5a and the second particles 5b, thereby improving the cell performance.

[0111] The structure of the fuel electrode 5 shown in FIG. 13 may be applied to the electrochemical cell devices according to the other embodiments described above.

[0112] Furthermore, 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 electrolytic cell, an electrolytic cell stack device, an electrolysis module, and an electrolysis device, respectively. The electrolytic cell has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen, or decomposes carbon dioxide into carbon monoxide and oxygen, 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 electrolytic cell, an electrolytic cell stack device, an electrolysis module, and an electrolysis device can improve cell performance and electrolysis performance.

[0113] The present disclosure has been described in detail above, but 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) an electrochemical cell includes a solid electrolyte layer, a first dopant, and CeO ２ and a first electrode including:

[0115] In one embodiment, the electrochemical cell (2) comprises a solid electrolyte layer and a first dopant and CeO ２ and a first electrode having a first surface located opposite the solid electrolyte layer and a second surface in contact with the solid electrolyte layer, wherein the ratio of the concentration of the first dopant to the total concentration of the first dopant and Ce gradually decreases from the second surface to the first surface.

[0116] (3) In the electrochemical cell of (1) or (2), the first electrode contains the first dopant and CeO ２and second particles having electronic conductivity and catalytic activity.

[0117] In one embodiment, the electrochemical cell device (4) has a cell stack including any one of the electrochemical cells (1) to (3) above.

[0118] In one embodiment, (5) a module includes the electrochemical cell device of (4) above, and a container that houses the electrochemical cell device.

[0119] In one embodiment, (6) a module housing device includes the module of (5) above, an auxiliary device for operating the module, and an exterior case for housing the module and the auxiliary device.

[0120] 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.

[0121] REFERENCE SIGNS LIST 1, 1A to 1C Cell 2 Support substrate 3 Element portion 4 Interconnector 5 Anode 5a First particle 5b Second particle 6 Solid electrolyte layer 7 Intermediate layer 8 Air electrode 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 51 First portion 52 Second portion 100 Module 110 Module accommodating device

Claims

1. A solid electrolyte layer, a first dopant and CeO ２ and a first electrode including:

2. A solid electrolyte layer, a first dopant and CeO ２ and a first electrode having a first surface located opposite the solid electrolyte layer and a second surface in contact with the solid electrolyte layer, wherein a ratio of a concentration of the first dopant to a total concentration of the first dopant and Ce gradually decreases from the second surface to the first surface.

3. The first electrode is a first dopant and CeO ２ 3. The electrochemical cell of claim 1 or 2, comprising first particles comprising:

4. An electrochemical cell device having a cell stack comprising the electrochemical cell according to any one of claims 1 to 3.

5. A module comprising the electrochemical cell device according to claim 4 and a container for housing said electrochemical cell device.

6. A module housing device comprising: a module according to claim 5; an auxiliary device for operating said module; and an exterior case for housing said module and said auxiliary device.

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