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

Abstract

To improve cell performance.SOLUTION: An electrochemical cell comprises a first electrode layer, a second electrode layer, and a solid electrolyte layer. The first electrode layer includes first material and second material having ion conductivity. The solid electrolyte layer is located between the first electrode layer and the second electrode layer, and contains Zr (zirconium). The first material has higher electron conductivity than the second material. The first electrode layer has a first portion including the first material, and a second portion located between the first portion and the solid electrolyte layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2014-524655 Summary of the Invention

[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 first electrode layer includes a first material and a second material having ion conductivity. The solid electrolyte layer is located between the first electrode layer and the second electrode layer and includes Zr (zirconium). The first material has higher electronic conductivity than the second material. The first electrode layer includes a first portion including the first material and a second portion located between the first portion and the solid electrolyte layer.

[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. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1A is a cross-sectional view showing an example of an electrochemical cell according to a first embodiment. [Figure 1B] FIG. 1B is a side view of an example of the electrochemical cell according to the first embodiment, viewed from the air electrode side. [Figure 1C] FIG. 1C is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the interconnector side. [Figure 2A] FIG. 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. [Figure 2B] FIG. 2B is a cross-sectional view taken along line XX shown in FIG. 2A. [Figure 2C] FIG. 2C is a top view showing an example of the electrochemical cell device according to the first embodiment. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a region R1 shown in FIG. 1A. [Figure 4] FIG. 4 is an external perspective view illustrating an example of the module according to the first embodiment. [Figure 5] FIG. 5 is an exploded perspective view schematically illustrating an example of a module housing device according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view of the electrochemical cell device according to the second embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing an example of an electrochemical cell according to the second embodiment. [Figure 8] FIG. 8 is an enlarged cross-sectional view of a region R2 shown in FIG. [Figure 9A] FIG. 9A is a perspective view showing an example of an electrochemical cell according to a third embodiment. [Figure 9B] FIG. 9B is a partial cross-sectional view of the electrochemical cell shown in FIG. 9A. [Figure 9C]FIG. 9C is an enlarged cross-sectional view of region R3 shown in FIG. 9B. [Figure 10A] FIG. 10A is a cross-sectional view showing an example of an electrochemical cell according to a fourth embodiment. [Figure 10B] FIG. 10B is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 10C] FIG. 10C is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 11] FIG. 11 is an enlarged cross-sectional view of a region R4 shown in FIG. 10A. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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.

[0010] 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.

[0011] [First embodiment] <Electrochemical cell configuration> First, with reference to Figures 1A to 1C, an electrochemical cell 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.

[0012] Fig. 1A is a cross-sectional view showing an example of an electrochemical cell according to the first embodiment, Fig. 1B is a side view of the example of the electrochemical cell according to the first embodiment as seen from the air electrode side, and Fig. 1C is a side view of the example of the electrochemical cell according to the first embodiment as seen from the interconnector side. Note that Figs. 1A to 1C show enlarged views of parts of each component of the electrochemical cell. Hereinafter, the electrochemical cell may also be simply referred to as a cell.

[0013] 1A to 1C, 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 is, for example, a rectangle with a side length in the length direction L of 5 cm to 50 cm and a length in the 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 is, for example, 1 mm to 5 mm.

[0014] 1A, the cell 1 includes a conductive support substrate 2, an element section 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.

[0015] The element section 3 is provided on a first surface n1 of the support substrate 2. The element section 3 has a fuel electrode layer 5, a solid electrolyte layer 6, and an air electrode layer 8. In the example shown in FIG. 1A, an interconnector 4 is located on a 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 electrode layer 8.

[0016] 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 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.

[0017] Each of the components that make up the cell 1 will be described below.

[0018] 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 is gas permeable, 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.

[0019] 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.

[0020] The fuel electrode layer 5 may be made of porous conductive ceramics. Examples of materials that may be used for the fuel electrode layer 5 include ceramics containing calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides, and Ni and / or NiO. The rare earth element oxide may contain a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides is sometimes referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia. The fuel electrode layer 5 is an example of a first electrode layer.

[0021] The fuel electrode layer 5 may also contain cerium oxide (CeO2) in which a rare earth element such as La (lanthanum), Gd (gadolinium), or Sm (samarium) is dissolved.The fuel electrode layer 5 may also contain a perovskite-type compound in which a rare earth element is dissolved, such as BaMO3 or SrMO3 (wherein M is Zr and / or Ce).

[0022] The content of ZrO2, CeO2, BaMO3, SrMO3, etc., in which rare earth element oxides are dissolved, in the fuel electrode layer 5 may be in the range of 35% to 65% by volume. The content of Ni and / or NiO may be in the range of 65% to 35% by volume. The porosity of the fuel electrode layer 5 may be 15% or more, particularly in the range of 20% to 40%. The thickness of the fuel electrode layer 5 may be 1 μm to 30 μm. Details of the fuel electrode layer 5 will be described later.

[0023] 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, making it difficult for leakage of fuel gas and oxygen-containing gas to occur.

[0024] The solid electrolyte layer 6 contains Zr. The material of the solid electrolyte layer 6 may be, for example, ZrO2 in which 3 mol % to 15 mol % of a rare earth element oxide, calcium oxide, or magnesium oxide is solid-solved. 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 material of the solid electrolyte layer 6 may be, for example, stabilized zirconia containing Yb. The solid electrolyte layer 6 may also contain, for example, a perovskite-type compound such as BaZrO3 or SrZrO3 in which a rare earth element such as Sc, Y, La, Nd, Sm, Gd, Dy, or Yb is solid-solved.

[0025] 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, for example, in the range of 20% to 50%, and particularly in the range of 30% to 50%.

[0026] There are no particular restrictions on the material of the air electrode layer 8, as long as it is one that is generally used for air electrodes. The material of the air electrode layer 8 may be, for example, a conductive ceramic such as a so-called ABO3-type perovskite oxide.

[0027] 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 O3, La x Sr 1-x MnO3, La x Sr 1-x FeO3, La x Sr 1-x CoO3, etc. Note that x is 0 <x<1、yは0<y<1である。

[0028] Furthermore, when the element section 3 includes an 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, a resistive layer such as SrZrO3 is formed in the solid electrolyte layer 6. The intermediate layer 7 makes it difficult for Sr to diffuse, thereby making it difficult for SrZrO3 and other electrically insulating oxides to form.

[0029] There are no particular restrictions on the material of intermediate layer 7, as long as it is generally used as an element diffusion prevention layer between air cathode layer 8 and solid electrolyte layer 6. The material of intermediate layer 7 may include, for example, cerium oxide (CeO2) in which a rare earth element other than Ce (cerium) is dissolved. Examples of such rare earth elements that may be used include Gd (gadolinium) and Sm (samarium).

[0030] Furthermore, the interconnector 4 is dense and makes it difficult for leakage of the fuel gas flowing through the gas flow channel 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.

[0031] The material for the interconnector 4 may be a lanthanum chromite-based perovskite oxide (LaCrO3-based oxide), a lanthanum strontium titanium-based perovskite oxide (LaSrTiO3-based oxide), or the like. These materials are conductive and are resistant to reduction and oxidation 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 alloy may be used as the material for the interconnector 4.

[0032] <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 the electrochemical cell device according to the first embodiment, Figure 2B is a cross-sectional view taken along line XX shown in Figure 2A, and Figure 2C is a top view showing an example of the electrochemical cell device according to the first embodiment.

[0033] As shown in FIG. 2A, the cell stack device 10 includes a cell stack 11 having a plurality of cells 1 arranged (stacked) in a thickness direction T of the cells 1 (see FIG. 1A), and a fixing member 12.

[0034] 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 gas tank 16, which are the support member 14, are made of, for example, metal and are electrically conductive.

[0035] 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 a fixing material 13.

[0036] 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.

[0037] In the example shown in Fig. 2A, fuel gas is stored in an internal space 22 formed by a support 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.

[0038] 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.

[0039] 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 a corresponding support 15. The gas tank 16 has two through-holes on its top surface. A support 15 is disposed in each through-hole. An internal space 22 is formed by the single 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 a single row of cell stacks 11, or three or more rows of cell stacks 11.

[0040] 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).

[0041] 2B, a fixing material 13 is filled and solidified in the joints between the inner walls of the insertion holes 15a and the lower ends of the cells 1. This bonds and fixes the inner walls of the insertion holes 15a to the lower ends of the multiple cells 1, respectively, 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.

[0042] 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.

[0043] As the crystallized glass, for example, any of materials such as SiO2-CaO, MgO-B2O3, La2O3-B2O3-MgO, La2O3-B2O3-ZnO, and SiO2-CaO-ZnO may be used, and in particular, SiO2-MgO materials may be used.

[0044] 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.

[0045] 2B, an end current collecting member 17 is electrically connected to the cell 1 located at the outermost position in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive part 19 that protrudes to the outside of the cell stack 11. The conductive part 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.

[0046] 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 part 19 of the cell stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0047] The positive electrode 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 electrode side end current collecting member 17 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, and is electrically connected to the negative electrode side end current collecting member 17 of the cell stack 11B.

[0048] The connection terminal 19C electrically connects the end current collecting member 17 on the negative electrode side of the cell stack 11A and the end current collecting member 17 on the positive electrode side of the cell stack 11B.

[0049] <Details of the fuel electrode layer> Next, the fuel electrode layer 5 according to the first embodiment will be described in detail with reference to Fig. 3. Fig. 3 is an enlarged cross-sectional view of region R1 shown in Fig. 1A.

[0050] As shown in Fig. 3, the fuel electrode layer 5 has a first portion 5A and a second portion 5B. The first portion 5A is located so as to contact the support substrate 2. The second portion 5B is located between the first portion 5A and the solid electrolyte layer 6. The thickness of the fuel electrode layer 5 may be, for example, 20 µm or less. The second portion 5B may be located so as to contact the solid electrolyte layer 6.

[0051] The fuel electrode layer 5 includes a first material and a second material, both of which have ionic conductivity. The first material has higher electronic conductivity than the second material. The electronic conductivities of the first material and the second material can be evaluated, for example, by fabricating a rectangular sintered body having the composition of the first material and a rectangular sintered body having the composition of the second material, and measuring the ionic transport number and electrical conductivity of each sintered body.

[0052] The first material may contain cerium. The first material may be, for example, a ceria-based compound containing CeO2. The first material may be, for example, CeO2 in which Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb, or the like is solid-solved. The first material may be, for example, a perovskite-type compound such as BaMO3 or SrMO3 (wherein M is Zr and / or Ce) in which a rare earth element such as Sc, Y, La, Nd, Sm, Gd, Dy, or Yb is solid-solved. The fuel electrode layer 5 may contain multiple types of first materials.

[0053] The second material contains Zr. The second material may be, for example, a zirconia-based compound or a perovskite-type compound. The second material may be, for example, stabilized zirconia containing Yb. The second material may be, for example, a perovskite-type compound such as BaZrO3 or SrZrO3 in which a rare earth element such as Sc, Y, La, Nd, Sm, Gd, Dy, or Yb is dissolved. The fuel electrode layer 5 may contain multiple types of second materials.

[0054] The first region 5A contains the first material. The first region 5A may have a higher content of the first material than the second region 5B. The second region 5B may have a higher content of the second material than the first region 5A. The first region 5A may have a higher content of the first material than the second material. The second region 5B may have a higher content of the second material than the first region 5A. The contents of the first and second materials can be confirmed, for example, by elemental analysis using an EPMA. Specifically, for example, a cross section of the element section 3 in the stacking direction is mirror-polished, and the fuel electrode layer 5 is divided into two equal parts in the thickness direction, with the first region 5A being the region adjacent to the support substrate 2 and the second region 5B being the region adjacent to the solid electrolyte layer 6. By semi-quantitatively analyzing the first and second materials in a predetermined area of ​​the cross section defined by the second region 5B, the contents per unit area of ​​each material can be calculated. The area for elemental analysis may be, for example, the area of ​​a rectangle whose sides are equal to or shorter than the thickness of the second region 5B. The content of the first material here refers to the mass of the main element (for example, Ce) that constitutes the first material relative to the total mass of elements detected in the measurement region.

[0055] Alternatively, the first region 5A and the second region 5B may be distinguished by, for example, determining by elemental analysis using an EPMA that a portion of the fuel electrode layer 5 has a higher content of the first material than the vicinity of the solid electrolyte layer 6 as the first region 5A and the portion near the solid electrolyte layer 6 as the second region 5B. Alternatively, the portion of the fuel electrode layer 5 has a higher content of the first material than the vicinity of the solid electrolyte layer 6 as the first region 5A and the remaining portion as the second region 5B. Specifically, for example, a cross section of the element unit 3 in the stacking direction is mirror-polished, and each element is subjected to area analysis or line analysis in the stacking direction using an EPMA to obtain a concentration map or concentration profile of each element. From the obtained concentration map or concentration profile results of each element, a region of the fuel electrode layer 5 where the content of the first material is higher than the vicinity of the solid electrolyte layer 6 or higher than the content of the second material can be determined as the first region 5A, and the remaining region can be determined as the second region 5B.

[0056] Thus, the first region 5A contains the first material having high electronic conductivity, thereby improving the electrode activity and electrical conductivity of the anode layer 5. Furthermore, by providing the second region 5B between the solid electrolyte layer 6 and the first region 5A, where the content of the first material is higher than that in the vicinity of the solid electrolyte layer 6 or higher than the content of the second material, components derived from the first material are less likely to diffuse into the solid electrolyte layer 6, making it less likely that a low-conductivity reaction layer will form in the solid electrolyte layer 6 or at the interface between the solid electrolyte layer 6 and the anode layer 5. As a result, the problem of a decrease in electrical conductivity between the solid electrolyte layer 6 and the anode layer 5 can be reduced. Therefore, the cell 1 according to this embodiment can improve power generation performance. The solid electrolyte layer 6 does not necessarily need to contain components of the first material, such as Sm, Gd, and Ce.

[0057] The porosity of the first portion 5A may be greater than the porosity of the second portion 5B, which allows the fuel gas to easily permeate through the first portion 5A located on the support substrate 2 side.

[0058] Furthermore, the thickness of the first portion 5A may be smaller than the thickness of the second portion 5B, which allows the fuel gas to easily permeate through the first portion 5A located on the support substrate 2 side.

[0059] Furthermore, when the surface of the anode layer 5 opposite the solid electrolyte layer 6 is defined as the first surface and the surface in contact with the solid electrolyte layer 6 is defined as the second surface, the content of the first material near the first surface may be higher than the content of the first material near the second surface. The "near the first surface" refers to a region of the anode layer 5 closer to the first surface than the solid electrolyte layer 6, and the "near the second surface" refers to a region of the anode layer 5 closer to the solid electrolyte layer 6 than the first surface. The average content of the first material may gradually decrease from the first surface to the second surface. The average content of the second material may gradually decrease from the second surface to the first surface. By having a higher content of the first material, which has high electronic conductivity, near the first surface than near the second surface, the electrode activity and electrical conductivity of the anode layer 5 can be improved. Furthermore, a low-conductivity reaction layer is less likely to form near the second surface.

[0060] The average content of each material can be obtained as follows. For example, a cross section of the element section 3 in the stacking direction is mirror-polished, and each element is analyzed by area analysis or by line analysis at least five locations in the stacking direction using an EPMA to obtain a concentration map or concentration profile for each element. The obtained concentration map or concentration profile data is integrated in the direction along the interface between the fuel electrode layer 5 and the solid electrolyte layer 6 to calculate the average concentration of each element. The average concentration of the main elements constituting each material obtained in this way can be used as the average content of each material.

[0061] <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 the module according to the first embodiment. Fig. 4 shows a state in which the front and rear surfaces, which are part of the storage container 101, have been removed and the cell stack device 10 of the fuel cell stored inside has been pulled out to the rear.

[0062] 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.

[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 also 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 2a 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 becomes 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, by accommodating the cell stack device 10 that improves power generation performance, the module 100 can be made to have improved power generation performance.

[0067] <Module storage device> Fig. 5 is an exploded perspective view showing an example of a module housing device according to the first embodiment. The module housing 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 accessory accommodating chamber 116 that accommodates accessory equipment for operating the module 100. Note that in Fig. 5, the accessory equipment accommodated in the accessory accommodating chamber 116 is omitted.

[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 that improves the power generation performance is provided in the module accommodating chamber 115, so that the module accommodating device 110 can be made to have improved power generation 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 a cell stack 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.

[0073] 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.

[0074] Fig. 6 is a cross-sectional view of an electrochemical cell device according to the second embodiment, and Fig. 7 is a transverse cross-sectional view showing an example of an electrochemical cell according to the second embodiment.

[0075] 6, in a cell stack device 10A according to the second embodiment, a plurality of cells 1A extend in a 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 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.

[0077] 7, the cell 1A includes a support substrate 2, a pair of element sections 3, and a sealing section 30. The support substrate 2 is columnar, having 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.

[0078] 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.

[0079] The cell 1A has a symmetrical shape with respect to a plane that passes through the center in the thickness direction T and is parallel to the main surface of the support substrate 2. The element section 3 has a fuel electrode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode layer 8 laminated in this order.

[0080] Fig. 8 is an enlarged cross-sectional view of region R2 shown in Fig. 7. As shown in Fig. 8, fuel electrode layer 5 has second portion 5B and first portion 5A located in this order from the solid electrolyte layer 6 side.

[0081] The solid electrolyte layer 6 contains Zr. The fuel electrode layer 5 has a first portion 5A containing the first material and a second portion 5B located between the first portion 5A and the solid electrolyte layer 6. This enhances the electrode activity and electrical conductivity of the fuel electrode layer 5. The content of the first material in the vicinity of the first surface of the fuel electrode layer 5 opposite the solid electrolyte layer 6 may be higher than the content of the first material in the vicinity of the second surface in contact with the solid electrolyte layer 6. This reduces the diffusion of components derived from the first material into the solid electrolyte layer 6, making it difficult for a low-conductivity reaction layer to form in the solid electrolyte layer 6 or at the interface between the solid electrolyte layer 6 and the fuel electrode layer 5. This reduces the problem of reduced electrical conductivity between the solid electrolyte layer 6 and the fuel electrode layer 5. Therefore, the cell 1A according to this embodiment can improve power generation performance.

[0082] [Third embodiment] Fig. 9A is a perspective view showing an example of an electrochemical cell according to Embodiment 3. Fig. 9B is a partial cross-sectional view of the electrochemical cell shown in Fig. 9A.

[0083] As shown in FIG. 9A, cell 1B has an element section 3B in which an anode layer 5, a solid electrolyte layer 6, and an air cathode layer 8 are stacked. In element section 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 to each other and have gas flow paths that supply gas to the anode layer 5 or the air cathode layer 8.

[0084] 9B, a sealing material is provided to hermetically seal a fuel gas flow path 98 and an oxygen-containing gas flow path 97 of the flat cell stack. The sealing material is a fixing member 96 for the cells, and includes 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.

[0085] The support member 94 may be a so-called separator that separates a fuel gas flow path 98 from an oxygen-containing gas flow path 97. 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.

[0086] 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.

[0087] Fig. 9C is an enlarged cross-sectional view of region R3 shown in Fig. 9B. As shown in Fig. 9C, fuel electrode layer 5 has second portion 5B and first portion 5A located in this order from the solid electrolyte layer 6 side.

[0088] The solid electrolyte layer 6 contains Zr. The fuel electrode layer 5 has a first portion 5A containing the first material and a second portion 5B located between the first portion 5A and the solid electrolyte layer 6. This enhances the electrode activity and electrical conductivity of the fuel electrode layer 5. The content of the first material in the vicinity of the first surface of the fuel electrode layer 5 opposite the solid electrolyte layer 6 may be higher than the content of the first material in the vicinity of the second surface in contact with the solid electrolyte layer 6. This reduces the diffusion of components derived from the first material into the solid electrolyte layer 6, making it difficult for a low-conductivity reaction layer to form in the solid electrolyte layer 6 or at the interface between the solid electrolyte layer 6 and the fuel electrode layer 5. This reduces the problem of reduced electrical conductivity between the solid electrolyte layer 6 and the fuel electrode layer 5. Therefore, the cell 1B according to this embodiment can improve power generation performance.

[0089] [Fourth embodiment] Fig. 10A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. Figs. 10B and 10C are cross-sectional views showing another example of an electrochemical cell according to the fourth embodiment. Fig. 11 is an enlarged view of region R4 shown in Fig. 10A. Note that Fig. 11 can also be applied to the examples of Figs. 10B and 10C.

[0090] As shown in FIGS. 10A to 10C, the cell 1C includes a support substrate 2 and an element section 3C including a laminate of an anode layer 5, a solid electrolyte layer 6, an intermediate layer 7, and an air cathode layer 8. The support substrate 2 has through-holes or pores in a portion in contact with the element section 3, 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 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.

[0091] In the example shown in Fig. 10A, the side surfaces of the fuel electrode layer 5 are covered with a solid electrolyte layer 6, which airtightly seals the gas flow channel 2a through which the fuel gas flows. As shown in Fig. 10B, the side surfaces of the fuel electrode 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 fuel electrode layer 5 may have electrical insulating properties.

[0092] 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. 10C.

[0093] Fig. 11 is an enlarged cross-sectional view of region R4 shown in Fig. 10A. As shown in Fig. 11, fuel electrode layer 5 has second portion 5B and first portion 5A located in this order from the solid electrolyte layer 6 side.

[0094] The solid electrolyte layer 6 contains Zr. The fuel electrode layer 5 has a first portion 5A containing the first material and a second portion 5B located between the first portion 5A and the solid electrolyte layer 6. This enhances the electrode activity and electrical conductivity of the fuel electrode layer 5. The content of the first material in the vicinity of the first surface of the fuel electrode layer 5 opposite the solid electrolyte layer 6 may be higher than the content of the first material in the vicinity of the second surface in contact with the solid electrolyte layer 6. This reduces the diffusion of components derived from the first material into the solid electrolyte layer 6, making it difficult for a low-conductivity reaction layer to form in the solid electrolyte layer 6 or at the interface between the solid electrolyte layer 6 and the fuel electrode layer 5. This reduces the problem of reduced electrical conductivity between the solid electrolyte layer 6 and the fuel electrode layer 5. Therefore, the cell 1C according to this embodiment can improve power generation performance.

[0095] <Other embodiments> Next, electrochemical cell devices according to other embodiments will be described.

[0096] 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.

[0097] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0098] As described above, the electrochemical cell (cell 1) according to this embodiment includes a first electrode layer (fuel electrode layer 5), a second electrode layer (air electrode layer 8), and a solid electrolyte layer 6. The first electrode layer includes a first material and a second material, both of which have ion conductivity. The solid electrolyte layer 6 is located between the first electrode layer and the second electrode layer and contains Zr. The first material has higher electronic conductivity than the second material. The first electrode layer includes a first portion 5A including the first material and a second portion 5B located between the first portion 5A and the solid electrolyte layer 6. This improves the cell performance, such as the power generation performance and electrolysis performance, of the electrochemical cell.

[0099] Furthermore, the electrochemical cell device (cell stack device 10) according to the embodiment has a cell stack 11 including the electrochemical cell described above. This makes it possible to improve the cell performance, such as the power generation performance and electrolysis performance, of the electrochemical cell device.

[0100] Moreover, the module 100 according to the embodiment includes the electrochemical cell device (cell stack device 10) described above and a storage container 101 that stores the electrochemical cell device. This allows the module 100 to have improved cell performance, such as power generation performance and electrolysis performance.

[0101] Furthermore, the module housing device 110 according to the embodiment includes the above-described module 100, accessories for operating the module 100, and an exterior case 111 for housing the module 100 and the accessories. This allows the module housing device 110 to improve cell performance such as power generation performance and electrolysis performance.

[0102] 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. [Explanation of symbols]

[0103] 1 cell 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 material 100 modules 110 Module storage device

Claims

1. A first electrode layer including metal Ni and a first material and a second material having ion conductivity; A second electrode layer; a solid electrolyte layer containing Zr (zirconium) and located between the first electrode layer and the second electrode layer; Equipped with the first material has a higher electronic conductivity than the second material; The first electrode layer has a first portion including the first material and a second portion including the second material and located between the first portion and the solid electrolyte layer. Electrochemical cell.

2. The first portion has a higher content of the first material than the second portion.

10. The electrochemical cell of claim 1.

3. The second portion has a content of the second material that is greater than a content of the first material.

10. The electrochemical cell of claim 1.

4. The first portion has a content of the first material that is greater than a content of the second material.

10. The electrochemical cell of claim 1.

5. The porosity of the first region is greater than the porosity of the second region.

10. The electrochemical cell of claim 1.

6. A first electrode layer including metal Ni and a first material and a second material having ion conductivity; A second electrode layer; a solid electrolyte layer containing Zr (zirconium) and located between the first electrode layer and the second electrode layer; Equipped with the first electrode layer has a first surface located on the opposite side of the solid electrolyte layer and a second surface in contact with the solid electrolyte layer; the first material has higher electronic conductivity than the second material, and a content of the first material near the first surface is higher than a content of the first material near the second surface; The second material is contained in the vicinity of the second surface. Electrochemical cell.

7. The content of the first material gradually decreases from the first surface to the second surface.

7. The electrochemical cell of claim 6.

8. The content of the second material gradually decreases from the second surface to the first surface.

7. The electrochemical cell of claim 6.

9. the first material is a ceria-based compound, The second material is a zirconia-based compound or a perovskite-based compound.

10. The electrochemical cell of claim 1 or 6.

10. The second material is stabilized zirconia.

10. The electrochemical cell of claim 1 or 6.

11. The first material is CeO in which Sm or Gd is solid-solved. ２ is 10. The electrochemical cell of claim 1 or 6.

12. A cell stack including the electrochemical cell according to claim 1 or 6. Electrochemical cell apparatus.

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

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

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