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

Abstract

To provide an electrochemical cell that can improve durability, an electrochemical cell device, a module, and a module housing device.SOLUTION: An electrochemical cell comprises a first electrode including Sr, a solid electrolyte layer including Zr, and an intermediate layer including Ce, Zr, and Sr. The intermediate layer is located between the first electrode and the solid electrolyte layer. The intermediate layer has a first portion located near the first electrode and a second portion located near the solid electrolyte layer. At least part of the second portion contains a larger amount of Sr than the average content of Sr in the first portion.SELECTED DRAWING: Figure 2

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 including multiple fuel cell units have been proposed as next-generation energy sources. A fuel cell unit is a type of cell that can generate electricity 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] Japanese Patent Application Laid-Open No. 2012-43801 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-26926 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional fuel cell stack devices have room for improvement in terms of durability.

[0005] An object of one aspect of the embodiment is to provide an electrochemical cell, an electrochemical cell device, a module, and a module housing device that can improve durability. [Means for solving the problem]

[0006] An electrochemical cell according to one aspect of the present invention includes a first electrode containing Sr, a solid electrolyte layer containing Zr, and an intermediate layer containing Ce, Zr, and Sr. The intermediate layer is located between the first electrode and the solid electrolyte layer. The intermediate layer has a first region located near the first electrode and a second region located near the solid electrolyte layer. At least some of the second regions contain more Sr than the average Sr content of the first regions.

[0007] The electrochemical cell device of the present disclosure also includes a cell stack including the electrochemical cell described above.

[0008] The module of the present disclosure includes the electrochemical cell device described above and a container that houses the electrochemical cell device.

[0009] 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. [Effects of the Invention]

[0010] According to one aspect of the embodiment, it is possible to provide an electrochemical cell, an electrochemical cell device, a module, and a module housing device that can improve durability. [Brief explanation of the drawings]

[0011] [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 2] FIG. 2 is a cross-sectional view showing an example in which a region R1 shown in FIG. 1A is enlarged. [Figure 3A] FIG. 3A is a cross-sectional view showing another example in which the region R1 shown in FIG. 1A is enlarged. [Figure 3B] FIG. 3B is a cross-sectional view showing an example in which the region R0 shown in FIG. 1A is enlarged. [Figure 4A] FIG. 4A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. [Figure 4B] FIG. 4B is a cross-sectional view taken along line XX shown in FIG. 4A. [Figure 4C] FIG. 4C is a top view showing an example of the electrochemical cell device according to the first embodiment. [Figure 5] FIG. 5 is an external perspective view showing an example of the module according to the first embodiment. [Figure 6] FIG. 6 is an exploded perspective view schematically illustrating an example of a module housing device according to the first embodiment. [Figure 7A] FIG. 7A is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. [Figure 7B] FIG. 7B is a cross-sectional view showing an example of an electrochemical cell according to the second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing an example in which the region R2 shown in FIG. 7B is enlarged. [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 10] FIG. 10 is a cross-sectional view showing an example in which the region R3 shown in FIG. 9B is enlarged. [Figure 11A] FIG. 11A is a cross-sectional view showing an example of an electrochemical cell according to a fourth embodiment. [Figure 11B] FIG. 11B is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 11C] FIG. 11C is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 12] FIG. 12 is a cross-sectional view showing an example in which a region R4 shown in FIG. 11A is enlarged. DETAILED DESCRIPTION OF THE INVENTION

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

[0015] Fig. 1A is a cross-sectional view showing an example of an electrochemical cell according to the first embodiment, Fig. 1B is a side view of the example of the electrochemical cell according to the first embodiment 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.

[0016] 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.

[0017] 1A, the cell 1 includes a conductive support substrate 2, an element section 3, and an interconnector 4. The support substrate 2 is columnar, 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.

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

[0019] 1B, the intermediate layer 7 and the air electrode 8 do 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. A portion of the surface of the intermediate layer 7 facing the air electrode 8 may be exposed to the outside. 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 surfaces 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. The entire surface of the intermediate layer 7 facing the air electrode 8 may be in contact with the air electrode 8.

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

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

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

[0023] The fuel electrode 5 is a second electrode that comes into contact with the fuel gas, which is a reducing gas. The fuel electrode 5 has gas permeability. The open porosity of the fuel electrode 5 may be, for example, in the range of 30% to 50%, and particularly 35% to 45%. The open porosity of the fuel electrode 5 may also be referred to as the porosity or void ratio of the fuel electrode 5.

[0024] A commonly known material can be used for the anode 5. The anode 5 may be made of porous conductive ceramics, such as ceramics containing calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides, and Ni and / or NiO. The rare earth element oxides may contain, for example, multiple 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.

[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 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 is dissolved. 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, for example, contain ZrO2 in which Yb, Sc, or Gd is dissolved, CeO2 in which La, Nd, or Yb is dissolved, BaZrO3 in which Sc or Yb is dissolved, or BaCeO3 in which Sc or Yb is dissolved.

[0027] The intermediate layer 7 functions as a diffusion-preventing layer. The intermediate layer 7 makes it difficult for Sr (strontium) contained in the air electrode 8 (described later) to diffuse into the solid electrolyte layer 6, thereby making it difficult for SrZrO3, which has high electrical resistance, to form in the solid electrolyte layer 6.

[0028] There are no particular restrictions on the material of the intermediate layer 7, as long as it is a material that is generally used for a Sr diffusion suppression layer. The material of the intermediate layer 7 includes, for example, cerium oxide (CeO2) in which rare earth elements other than Ce (cerium) are dissolved. Examples of such rare earth elements include Gd (gadolinium) and Sm (samarium).

[0029] The air electrode 8 is a first electrode that comes into contact with an oxygen-containing gas. The air electrode 8 has gas permeability. The open porosity of the air electrode 8 may be, for example, in the range of 20% to 50%, and particularly in the range of 30% to 50%. The open porosity of the air electrode 8 may also be referred to as the porosity of the air electrode 8.

[0030] There are no particular restrictions on the material of the air electrode 8 as long as it is one that is generally used for air electrodes. The material of the air electrode 8 may be, for example, a conductive ceramic such as a so-called ABO3-type perovskite oxide.

[0031] The air electrode 8 contains Sr. 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 Sr1-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。

[0032] 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.

[0033] Lanthanum chromite-based perovskite oxides (LaCrO3-based oxides), lanthanum strontium titanium-based perovskite oxides (LaSrTiO3-based oxides), etc. may be used as the material for the interconnector 4. These materials are conductive and are resistant to reduction and oxidation even when in contact with fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air.

[0034] <Details of the middle layer> Next, details of the intermediate layer 7 of the electrochemical cell according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing an example in which a region R1 shown in Fig. 1A is enlarged.

[0035] 2, the intermediate layer 7 has a first portion 7A and a second portion 7B. The first portion 7A is located near the air electrode 8. The second portion 7B is located near the solid electrolyte layer 6.

[0036] The first region 7A refers to a region included in a range of (1 / 2)t from the air electrode 8, where t is the average thickness of the intermediate layer 7. In other words, when the thickness of the first region 7A is t1, there is a relationship of t1=(1 / 2)t.

[0037] When the average thickness of the intermediate layer 7 is t, the second region 7B refers to a region included in the range of (1 / 2)t from the solid electrolyte layer 6. In other words, when the thickness of the second region 7B is t2, the relationship t2=(1 / 2)t holds.

[0038] At least a portion of the second region 7B contains more Sr than the average Sr content in the first region 7A. When the second region 7B facing the solid electrolyte layer 6 has a portion containing more Sr than the average Sr content in the first region 7A, Zr contained in the solid electrolyte layer 6 is less likely to diffuse into the first region 7A and the air electrode 8. This makes it easier to maintain the strength of the intermediate layer 7. As a result, the bonding strength between the solid electrolyte layer 6 and the intermediate layer 7 and the bonding strength between the intermediate layer 7 and the air electrode 8 are less likely to decrease, improving the durability of the cell 1.

[0039] The average Sr content in the second region 7B may be greater than the average Sr content in the first region 7A. This makes it even more difficult for Zr contained in the solid electrolyte layer 6 to diffuse into the first region 7A and the air electrode 8. This makes it even easier to maintain the strength of the intermediate layer 7, making it even more difficult for the bond strength between the solid electrolyte layer 6 and the intermediate layer 7 to decrease, and further improving the durability of the cell 1.

[0040] The average Sr content of the second portion 7B may be 0.1 atomic % or more, 0.2 atomic % or more, or even 1 atomic % or more, relative to the total amount of metal elements contained in the second portion 7B. This further reduces the likelihood of Zr contained in the solid electrolyte layer 6 diffusing toward the air electrode 8. This further improves the strength of the solid electrolyte layer 6 and the intermediate layer 7, making it more difficult for the bond strength between the solid electrolyte layer 6 and the intermediate layer 7 and the bond strength between the intermediate layer 7 and the air electrode 8 to decrease, thereby further improving the durability of the cell 1.

[0041] The average Sr content in the second portion 7B may be 7 atomic % or less, 5 atomic % or less, or even 3 atomic % or less, relative to the total amount of metal elements contained in the second portion 7B. This makes it less likely that SrZrO3, which has high electrical resistance, will be formed excessively due to a reaction between Sr and Zr contained in the solid electrolyte layer 6, and makes it less likely that the power generation performance of the cell 1 will deteriorate.

[0042] The Sr and other metal element contents in the first region 7A and the second region 7B can be determined, for example, by elemental analysis of the intermediate layer 7 using an EPMA. Whether at least a portion of the second region 7B contains more Sr than the average Sr content in the first region 7A can also be determined by elemental analysis of the intermediate layer 7 using an EPMA. For example, a portion of the second region 7B where the Sr content is determined to be higher than the other portions can be identified, and the Sr content in that portion can be compared with the average Sr content in the first region 7A. Specifically, for example, a cross section of the element unit 3 including the intermediate layer 7 in the stacking direction is mirror-polished, and Sr is analyzed by area analysis or line analysis in the stacking direction using an EPMA to obtain a Sr concentration map or concentration profile. Based on the obtained Sr concentration map or concentration profile, it can be determined whether or not a portion of the second region 7B of the intermediate layer 7 contains more Sr than the average Sr content in the first region 7A.

[0043] The intermediate layer 7 may have pores. The intermediate layer 7 may have a porous portion having a large number of pores. When the intermediate layer 7 has a porous portion, even if the thermal expansion coefficient of the intermediate layer 7 differs from that of the solid electrolyte layer 6, the stress generated due to the difference in the thermal expansion coefficients is alleviated, making it less likely for cracks to occur in the solid electrolyte layer 6. The porous portion may be located in either or both of the first portion 7A and the second portion 7B. The porosity of the second portion 7B may be greater than the porosity of the first portion 7A.

[0044] The Sr content in the first portion 7A and the second portion 7B can be adjusted, for example, by changing the temperature and time set when heat treating the material of the intermediate layer 7 in the process of forming the element portion 3. However, the method of forming the element portion 3 is not limited to the above.

[0045] Fig. 3A is an enlarged cross-sectional view showing another example of region R1 shown in Fig. 1A. As shown in Fig. 3A, second portion 7B may have boundary portion 7Ba including interface 70 with solid electrolyte layer 6.

[0046] When the average thickness of the intermediate layer 7 is t, the boundary portion 7Ba refers to a region included in the range of (1 / 4)t from the solid electrolyte layer 6. In other words, when the thickness of the boundary portion 7Ba is t3, the relationship t3=(1 / 4)t holds.

[0047] The boundary portion 7Ba may contain more Sr than the second portion 7B other than the boundary portion 7Ba. The boundary portion 7Ba may contain Zr and may further contain SrZrO3. This increases the bonding strength between the solid electrolyte layer 6 and the intermediate layer 7, further improving the durability of the cell 1.

[0048] 3B is a cross-sectional view showing an example in which the region R0 shown in FIG.

[0049] The first region 71 is a region of the intermediate layer 7 that overlaps with the air electrode 8 as the first electrode when viewed from above. The second region 72 is a region of the intermediate layer 7 other than the first region 71. In other words, the second region 72 is a region located outside the outline of the air electrode 8 as the first electrode when viewed from above.

[0050] The average Zr content of the second portions 7B located in the second region 72 may be greater than the average Zr content of the second portions 7B located in the first region 71. In other words, the Zr contained in the solid electrolyte layer 6 may be diffused more in the second portions 7B located in the second region 72 than in the second portions 7B located in the first region 71. This increases the bonding strength between the solid electrolyte layer 6 and the intermediate layer 7 in the second region 72, which is the outer periphery of the element portion 3 and where peeling between the solid electrolyte layer 6 and the intermediate layer 7 is likely to occur, thereby improving the durability of the cell 1. In the second region 72, the first portions 7A may contain Zr.

[0051] Furthermore, in plan view, in the first region 71 overlapping with the air electrode 8, Zr contained in the solid electrolyte layer 6 diffuses less into the second region 7B and even less into the first region 7A. Therefore, a solid solution containing Ce and Zr, which has high electrical resistance, is less likely to form in the intermediate layer 7 located in the first region 71, and the power generation performance of the cell 1 is less likely to deteriorate.

[0052] <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. 4A to 4C. Fig. 4A is a perspective view showing an example of the electrochemical cell device according to the first embodiment. Fig. 4B is a cross-sectional view taken along line XX shown in Fig. 4A. Fig. 4C is a top view showing an example of the electrochemical cell device according to the first embodiment.

[0053] As shown in FIG. 4A, 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.

[0054] 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.

[0055] 4B, 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.

[0056] 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.

[0057] In the example shown in FIG. 4A, fuel gas is stored in an internal space 22 (see FIG. 4B) 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. 5), which will be described later.

[0058] 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.

[0059] The example shown in FIG. 4A 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 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 one gas tank 16 and two supports 15. The cell stack device 10 may include only one cell stack 11, or may include three or more cell stacks 11.

[0060] The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. For example, the length of the insertion hole 15a in the arrangement direction of the cells 1, i.e., the thickness direction T, is greater than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. For example, the width of the insertion hole 15a is greater than the length of the cell 1 in the width direction W (see FIG. 1A).

[0061] 4B, 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.

[0062] 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.

[0063] 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.

[0064] 4B, 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 adjacent 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 adjacent cell 1.

[0065] As shown in Fig. 4B, 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. 4A.

[0066] 4C, 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 part 19 of the cell stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0067] 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.

[0068] 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.

[0069] <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. 5. Fig. 5 is an external perspective view showing an example of a module according to a first embodiment. Fig. 5 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.

[0070] 5, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container. A reformer 102 is disposed above the cell stack device 10.

[0071] 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, which is a highly efficient reforming reaction.

[0072] 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.

[0073] 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.

[0074] In such a module 100, as described above, by accommodating the cell stack device 10, which has improved durability, the module 100 can be made to have improved durability.

[0075] <Module storage device> Fig. 6 is an exploded perspective view schematically illustrating 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. 5, 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. 6.

[0076] An exterior case 111 of a module accommodating device 110 shown in Fig. 6 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. 6, the accessory equipment accommodated in the accessory accommodating chamber 116 is omitted.

[0077] 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.

[0078] In such a module housing device 110, as described above, the module housing chamber 115 is provided with the module 100 having improved durability, so that the module housing device 110 can have improved durability.

[0079] 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.

[0080] [Second embodiment] Next, an electrochemical cell and an electrochemical cell device according to a second embodiment will be described with reference to FIGS. 7A to 8. FIG.

[0081] In the above-described embodiment, a so-called "vertical stripe type" electrochemical cell device has been exemplified, in which only one element unit including a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the surface of a support substrate. However, the present invention can also be applied to a horizontal stripe type electrochemical cell device in which so-called "horizontal stripe type" electrochemical cells are arranged, in which element units are provided at multiple locations spaced apart from each other on the surface of a support substrate, and adjacent element units are electrically connected.

[0082] Fig. 7A is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. Fig. 7B is a transverse cross-sectional view showing an example of an electrochemical cell according to the second embodiment. Fig. 8 is an enlarged view showing an example of a region R2 shown in Fig. 7B.

[0083] 7A, in the cell stack device 10A, 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 parts 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.

[0084] Moreover, 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 respective cells 1A, and connect the adjacent cells 1A.

[0085] 7B, the cell 1A according to this embodiment includes a support substrate 2, a pair of element sections 3, and a sealing section 30. The support substrate 2 is columnar and has a pair of opposing flat surfaces, a first surface n1 and a second surface n2, and a pair of arc-shaped side surfaces m connecting the first surface n1 and the second surface n2.

[0086] 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.

[0087] 8, the intermediate layer 7 has a first portion 7A and a second portion 7B. The first portion 7A is located near the air electrode 8. The second portion 7B is located near the solid electrolyte layer 6.

[0088] The first region 7A refers to a region included in the range of (1 / 2)t from the air electrode 8, where t is the average thickness of the intermediate layer 7. The second region 7B refers to a region included in the range of (1 / 2)t from the solid electrolyte layer 6, where t is the average thickness of the intermediate layer 7.

[0089] At least a portion of the second region 7B contains more Sr than the average Sr content of the first region 7A. When the second region 7B facing the solid electrolyte layer 6 has a portion containing more Sr than the average Sr content of the first region 7A, Zr contained in the solid electrolyte layer 6 is less likely to diffuse into the first region 7A and the air electrode 8. This makes it easier to maintain the strength of the intermediate layer 7. This makes it less likely that the bonding strength between the solid electrolyte layer 6 and the intermediate layer 7, and between the intermediate layer 7 and the air electrode 8 will decrease, improving the durability of the cell 1A.

[0090] The average Sr content in the second region 7B may be greater than the average Sr content in the first region 7A. This further reduces the likelihood of Zr contained in the solid electrolyte layer 6 diffusing into the first region 7A and the air electrode 8. This further improves the ability to maintain the strength of the intermediate layer 7, making it even more difficult for the bond strength between the solid electrolyte layer 6 and the intermediate layer 7 to decrease, and further improving the durability of the cell 1A.

[0091] [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.

[0092] 9A and 9B, cell 1B has an element section 3B in which an anode 5, a solid electrolyte layer 6, an intermediate layer 7, and an air electrode 8 are stacked, and conductive members 91 and 92. In an electrochemical cell device in which a plurality of flat cells are stacked, for example, the plurality of cells 1B are electrically connected by conductive members 91 and 92, which are adjacent metal layers. The conductive members 91 and 92 electrically connect adjacent cells 1B to each other and have gas flow paths for supplying gas to the anode 5 or the air electrode 8.

[0093] 9B, 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 cell fixing member 96, 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.

[0094] 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. If the support member 94 is made of metal, the support member 94 may be integrated with the conductive member 92. If the support member 95 is made of metal, the support member 95 may be integrated with the conductive member 91.

[0095] 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.

[0096] 10 is an enlarged cross-sectional view of an example of region R3 shown in FIG. 9B. As shown in FIG. 10, intermediate layer 7 has first portion 7A and second portion 7B. First portion 7A is located near air electrode 8. Second portion 7B is located near solid electrolyte layer 6.

[0097] The first region 7A refers to a region included in the range of (1 / 2)t from the air electrode 8, where t is the average thickness of the intermediate layer 7. The second region 7B refers to a region included in the range of (1 / 2)t from the solid electrolyte layer 6, where t is the average thickness of the intermediate layer 7.

[0098] At least a portion of the second region 7B contains more Sr than the average Sr content of the first region 7A. When the second region 7B facing the solid electrolyte layer 6 has a portion containing more Sr than the average Sr content of the first region 7A, Zr contained in the solid electrolyte layer 6 is less likely to diffuse into the first region 7A and the air electrode 8. This makes it easier to maintain the strength of the intermediate layer 7. This makes it less likely that the bonding strength between the solid electrolyte layer 6 and the intermediate layer 7 and between the intermediate layer 7 and the air electrode 8 will decrease, improving the durability of the cell 1B.

[0099] The average Sr content in the second region 7B may be greater than the average Sr content in the first region 7A. This makes it even more difficult for Zr contained in the solid electrolyte layer 6 to diffuse into the first region 7A and the air electrode 8. This makes it even easier to maintain the strength of the intermediate layer 7, making it even more difficult for the bond strength between the solid electrolyte layer 6 and the intermediate layer 7 to decrease, and further improving the durability of the cell 1B.

[0100] [Fourth embodiment] Fig. 11A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. Figs. 11B and 11C are cross-sectional views showing another example of an electrochemical cell according to the fourth embodiment. Fig. 12 is a cross-sectional view showing an example in which region R4 shown in Fig. 11A is enlarged. Note that Fig. 12 can also be applied to the examples of Figs. 11B and 11C.

[0101] As shown in FIGS. 11A to 11C, a cell 1C includes an element section 3C in which an anode 5, a solid electrolyte layer 6, an intermediate layer 7, and a cathode 8 are stacked, and a support substrate 2. The support substrate 2 has through-holes or pores in a portion in contact with the element section 3C, and also includes a member 120 located outside the gas flow path 2a. The support substrate 2 allows gas to flow between the gas flow path 2a and the element section 3C. The support substrate 2 may be composed of, for example, one or more metal plates. The material of the metal plate may contain chromium. The metal plate may have a conductive coating layer. The support substrate 2 electrically connects adjacent cells 1C. The element section 3C may be formed directly on the support substrate 2, or may be bonded to the support substrate 2 with a bonding material.

[0102] 11A, the side surfaces of the anode 5 are covered with a solid electrolyte layer 6, which airtightly seals a gas flow channel 2a through which the fuel gas flows. As shown in FIG. 11B, the side surfaces of the anode 5 may be covered and sealed with a sealant 9 made of dense glass or ceramic. The sealant 9 covering the side surfaces of the anode 5 may have electrical insulating properties.

[0103] 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.

[0104] 12, the intermediate layer 7 has a first portion 7A and a second portion 7B. The first portion 7A is located near the air electrode 8. The second portion 7B is located near the solid electrolyte layer 6.

[0105] The first region 7A refers to a region included in the range of (1 / 2)t from the air electrode 8, where t is the average thickness of the intermediate layer 7. The second region 7B refers to a region included in the range of (1 / 2)t from the solid electrolyte layer 6, where t is the average thickness of the intermediate layer 7.

[0106] At least a portion of the second region 7B contains more Sr than the average Sr content of the first region 7A. The second region 7B facing the solid electrolyte layer 6 has a portion containing more Sr than the average Sr content of the first region 7A, which makes it difficult for Zr contained in the solid electrolyte layer 6 to diffuse into the first region 7A and the air electrode 8. This makes it easier to maintain the strength of the intermediate layer 7. This makes it difficult for the bonding strength between the solid electrolyte layer 6 and the intermediate layer 7 and between the intermediate layer 7 and the air electrode 8 to decrease, improving the durability of the cell 1C.

[0107] The average Sr content in the second portion 7B may be greater than the average Sr content in the first portion 7A. This makes it even more difficult for Zr contained in the solid electrolyte layer 6 to diffuse into the first portion 7A and the air electrode 8. This makes it even easier to maintain the strength of the intermediate layer 7, making it even more difficult for the bond strength between the solid electrolyte layer 6 and the intermediate layer 7 to decrease, and further improving the durability of the cell 1C.

[0108] [Other embodiments] In the above 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 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 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 and durability.

[0109] 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.

[0110] In one embodiment, (1) an electrochemical cell includes a first electrode comprising Sr; a solid electrolyte layer containing Zr; an intermediate layer located between the first electrode and the solid electrolyte layer and containing Ce, Zr, and Sr; Equipped with the intermediate layer has a first portion located near the first electrode and a second portion located near the solid electrolyte layer; At least a portion of the second regions contains more Sr than the average Sr content of the first regions.

[0111] (2) In the electrochemical cell of (1) above, the average Sr content of the second regions may be greater than the average Sr content of the first regions.

[0112] (3) In the electrochemical cell of (1) or (2), the second portion has a boundary portion including an interface with the solid electrolyte layer, The boundary portion may contain more Sr than the second portion other than the boundary portion.

[0113] (4) In the electrochemical cell of any one of (1) to (3) above, the second region may have an average Sr content of 0.1 atomic % or more relative to the total amount of metal elements contained in the second region.

[0114] (5) In the electrochemical cell of (4) above, the second region may have an average Sr content of 7 atomic % or less relative to the total amount of metal elements contained in the second region.

[0115] (6) In the electrochemical cell of (5) above, in a plan view from the first electrode, the intermediate layer has a first region overlapping with the first electrode and a second region positioned outside the outline of the first electrode; The second portions located in the second region may have a higher average Zr content than the second portions located in the first region.

[0116] In one embodiment, the electrochemical cell device (7) may have a cell stack including any one of the electrochemical cells (1) to (6) above.

[0117] In one embodiment, the module (8) comprises the electrochemical cell device (7) described above, and a container for housing the electrochemical cell device.

[0118] In one embodiment, the module storage device (9) includes the module (8) and Auxiliary equipment for operating the module; and an exterior case that houses the module and the auxiliary equipment.

[0119] 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]

[0120] 1,1A~1C cell 2 Support substrate 3. Element section 4 Interconnector 5 Fuel electrode 6 Solid electrolyte layer 7. Middle class 7A 1st part 7B 2nd part 8 Air electrode 10 Cell stack device 11 Cell stack 12 Fixing member 13 Fixing material 14 Support member 15 Support 16 Gas Tank 17 End current collecting member 18 Connecting member 100 modules 110 Module storage device

Claims

1. a first electrode containing Sr; a solid electrolyte layer containing Zr; an intermediate layer located between the first electrode and the solid electrolyte layer and containing Ce, Zr, and Sr; Equipped with the intermediate layer has a first portion located near the first electrode and a second portion located near the solid electrolyte layer; At least a portion of the second region contains more Sr than the average Sr content of the first region. Electrochemical cell.

2. The average Sr content of the second region is greater than the average Sr content of the first region.

10. The electrochemical cell of claim 1.

3. the second portion has a boundary portion including an interface with the solid electrolyte layer, The boundary portion contains more Sr than the second portion other than the boundary portion.

10. The electrochemical cell of claim 1.

4. The average Sr content of the second region is 0.1 atomic % or more with respect to the total amount of metal elements contained in the second region.

10. The electrochemical cell of claim 1.

5. The average Sr content of the second region is 7 atomic % or less with respect to the total amount of metal elements contained in the second region.

5. The electrochemical cell of claim 4.

6. When viewed from above from the first electrode, the intermediate layer has a first region overlapping with the first electrode and a second region positioned outside the outline of the first electrode, The average Zr content of the second portions located in the second region is greater than the average Zr content of the second portions located in the first region.

6. The electrochemical cell of claim 5.

7. A cell stack comprising the electrochemical cell according to any one of claims 1 to 6. Electrochemical cell apparatus.

8. The electrochemical cell device according to claim 7 ; a container for housing the electrochemical cell device; A module comprising:

9. A module according to claim 8; 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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