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

Abstract

The present invention provides a solid electrolyte layer, electrochemical cell, electrochemical cell apparatus, module, and module housing apparatus that can improve durability. [Solution] The solid electrolyte layer has a first surface and a second surface located at both ends in the thickness direction, and contains a plurality of pores. The plurality of pores have a major axis extending in the direction along the first surface, and include a flattened first pore. In a cross-section along the thickness direction, the first area ratio, which is the area ratio occupied by the first pore, is 2% or more and 10% or less.

Description

[Technical Field]

[0001] This disclosure relates to a solid electrolyte layer, an electrochemical cell, an electrochemical cell apparatus, a module, and a module housing apparatus. [Background technology]

[0002] In recent years, various fuel cell cell stack devices, which have multiple fuel cell cells, have been proposed as next-generation energy sources. A fuel cell is a type of electrochemical cell that can generate electricity using a fuel gas such as hydrogen-containing gas and an oxygen-containing gas such as air. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2013 / 031961 [Patent Document 2] Japanese Patent Publication No. 2023-130811 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional fuel cell cell stack devices had room for improvement in terms of durability.

[0005] One embodiment aims to provide a solid electrolyte layer, an electrochemical cell, an electrochemical cell apparatus, a module, and a module housing apparatus that can improve durability. [Means for solving the problem]

[0006] A solid electrolyte layer according to one embodiment has a first surface and a second surface located at both ends in the thickness direction, and contains a plurality of pores. The plurality of pores have a major axis extending in the direction along the first surface and include a flattened first pore. In the cross-section along the thickness direction, the first area ratio, which is the area ratio occupied by the first pore, is 2% or more and 10% or less.

[0007] Furthermore, the electrochemical cell of this disclosure comprises the solid electrolyte layer described above.

[0008] Furthermore, the electrochemical cell apparatus of this disclosure has a cell stack comprising the electrochemical cells described above.

[0009] Furthermore, the module of this disclosure comprises the electrochemical cell apparatus described above and a storage container housing the electrochemical cell apparatus.

[0010] Furthermore, the module housing device of this disclosure comprises the module described above, an auxiliary device configured to operate the module, and an outer case housing the module and the auxiliary device. [Effects of the Invention]

[0011] According to one embodiment, a solid electrolyte layer, an electrochemical cell, an electrochemical cell apparatus, a module, and a module housing apparatus can be provided that can improve durability. [Brief explanation of the drawing]

[0012] [Figure 1A] Figure 1A is a cross-sectional view showing an example of an electrochemical cell according to the first embodiment. [Figure 1B] Figure 1B is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the air electrode side. [Figure 1C] Figure 1C is a side view of an example of an electrochemical cell according to the first embodiment, as seen from the interconnector side. [Figure 2] Figure 2 is an enlarged cross-sectional view of region R1 shown in Figure 1A. [Figure 3A] Figure 3A is a perspective view showing an example of an electrochemical cell apparatus according to the first embodiment. [Figure 3B] Figure 3B is a cross-sectional view of the XX line shown in Figure 3A. [Figure 3C] Figure 3C is a top view showing an example of an electrochemical cell apparatus according to the first embodiment. [Figure 4] FIG. 4 is an external perspective view showing an example of a module according to the first embodiment. [Figure 5] FIG. 5 is an exploded perspective view schematically showing an example of a module housing device according to the first embodiment. [Figure 6A] FIG. 6A is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. [Figure 6B] FIG. 6B is a cross-sectional view showing an electrochemical cell according to the second embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a region R2 shown in FIG. 6B. [Figure 8A] FIG. 8A is a perspective view showing an example of an electrochemical cell according to the third embodiment. [Figure 8B] FIG. 8B is a partial cross-sectional view of the electrochemical cell shown in FIG. 8A. [Figure 9] FIG. 9 is an enlarged cross-sectional view of a region R3 shown in FIG. 8B. [Figure 10A] FIG. 10A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. [Figure 10B] FIG. 10B is a cross-sectional view showing another example of an electrochemical cell according to the fourth embodiment. [Figure 10C] FIG. 10C is a cross-sectional view showing another example of an 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. MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of a solid electrolyte layer, 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. Note that the present disclosure is not limited by the embodiments shown below.

[0014] Furthermore, it is important to note that drawings are schematic representations, and the dimensional relationships and proportions of each element may differ from reality. Moreover, there may be discrepancies in dimensional relationships and proportions between drawings themselves.

[0015] [First Embodiment] <Configuration of an electrochemical cell> First, with reference to Figures 1A to 1C, the electrochemical cell according to the first embodiment will be described using an example of a solid oxide fuel cell. The electrochemical cell device may include a cell stack having multiple electrochemical cells. An electrochemical cell device having multiple electrochemical cells will simply be referred to as a cell stack device.

[0016] Figure 1A is a cross-sectional view showing an example of an electrochemical cell according to the first embodiment. Figure 1B is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the air electrode side. Figure 1C is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the interconnector side. Figures 1A to 1C show enlarged views of some of the components of the electrochemical cell. Hereinafter, the electrochemical cell may simply be referred to as a cell.

[0017] In the examples shown in Figures 1A to 1C, cell 1 may be a hollow flat plate or an elongated plate. As shown in Figure 1B, the overall shape of cell 1 when viewed from the side may be, for example, a rectangle with a length of 5 cm to 50 cm along the length direction L and a width direction W perpendicular to this length direction L, for example, 1 cm to 10 cm. The overall thickness direction T of cell 1 may be, for example, 1 mm to 5 mm.

[0018] As shown in Figure 1A, cell 1 comprises a conductive support substrate 2, an element section 3, and an interconnector 4. The support substrate 2 may be columnar in shape, having a pair of opposing flat surfaces n1 and n2, and a pair of arc-shaped side surfaces m connecting surfaces n1 and n2.

[0019] The element portion 3 is located on the surface n1 of the support substrate 2. This element portion 3 comprises a fuel electrode 5, a solid electrolyte layer 6, and an air electrode 8.

[0020] Furthermore, as shown in Figure 1B, the air electrode 8 does not extend to the lower end of cell 1. At the lower end of cell 1, only the solid electrolyte layer 6 is exposed on the surface of plane n1. Also, as shown in Figure 1C, the interconnector 4 may extend to the lower end of cell 1. At the lower end of cell 1, both the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. Note that, as shown in Figure 1A, the solid electrolyte layer 6 is exposed on the surface of the pair of arc-shaped side surfaces m of cell 1. The interconnector 4 does not necessarily have to extend to the lower end of cell 1.

[0021] The following describes each component that makes up Cell 1.

[0022] The support substrate 2 has gas passages 2a inside through which gas flows. An example of the support substrate 2 shown in Figure 1A has six gas passages 2a. The support substrate 2 is gas permeable and allows the fuel gas flowing through the gas passages 2a to pass through to the fuel electrode 5. The support substrate 2 may also be conductive. A conductive support substrate 2 collects the electricity generated in the element section 3 and sends it to the interconnector 4.

[0023] The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. The iron group metal component may be, for example, Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc (scandium), Y (yttrium), La (lanthanum), Nd (neodymium), Sm (samarium), Gd (gadolinium), Dy (dysprosium), and Yb (ytterbium).

[0024] The fuel electrode 5 is the first electrode in contact with the reducing fuel gas. The fuel electrode 5 is gas permeable. The open porosity of the fuel electrode 5 may be in the range of, for example, 30% to 50%, and particularly 35% to 45%. The open porosity of the fuel electrode 5 is sometimes referred to as the porosity or void ratio of the fuel electrode 5.

[0025] The fuel electrode 5 contains metal particles. The metal particles may be, for example, Ni. The fuel electrode 5 may also contain porous conductive ceramics, such as ceramics containing ZrO2 in which calcium oxide, magnesium oxide, or rare earth element oxides are in solid solution, and Ni and / or NiO. These rare earth element oxides may include, for example, multiple rare earth elements selected from Sc, Y, La, Ce, Nd, Sm, Gd, Dy, and Yb. ZrO2 in which calcium oxide, magnesium oxide, or rare earth element oxides are in solid solution may also be referred to as stabilized zirconia. The stabilized zirconia may include partially stabilized zirconia. The fuel electrode 5 may also contain CeO2 in which Y, La, Nd, Gd, Sm, or Yb are in solid solution.

[0026] The solid electrolyte layer 6 is an electrolyte that facilitates ion transfer between the fuel electrode 5 and the air electrode 8. At the same time, the solid electrolyte layer 6 has gas barrier properties, making it difficult for leaks between the fuel gas and the oxygen-containing gas to occur.

[0027] The material of the solid electrolyte layer 6 may be, for example, ZrO2 in which 3 mol% to 15 mol% of rare earth element oxides are dissolved. The rare earth element oxides may include, for example, one or more rare earth elements selected from Sc, Y, La, Ce, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may also contain, for example, ZrO2 in which Y, Yb, Sc, or Gd are dissolved, or BaZrO3 in which Sc, Y, or Yb are dissolved. Details of the solid electrolyte layer 6 will be described later.

[0028] The air electrode 8 is a second electrode in 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%, particularly 30% to 50%. The open porosity of the air electrode 8 is sometimes referred to as the porosity of the air electrode 8.

[0029] The air electrode 8 contains inorganic oxide particles. There is no particular limitation on the material of the air electrode 8 as long as it 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.

[0030] The material of the air electrode 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. An example of such a composite oxide is 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, and the like. Note that x satisfies 0<x<1, and y satisfies 0<y<1.

[0031] Further, the interconnector 4 is dense, and makes it difficult for leakage of the fuel gas flowing through the gas flow path 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2 to occur. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0032] As the material of the interconnector 4, a lanthanum chromite-based perovskite oxide (LaCrO3-based oxide), a lanthanum strontium titanium-based perovskite oxide (LaSrTiO3-based oxide), or the like may be used. These materials have electrical conductivity, and are hardly reduced or oxidized even when brought into contact with a fuel gas such as a hydrogen-containing gas and an oxygen-containing gas such as air.

[0033] Furthermore, the element section 3 may further include an intermediate layer 7 located between the solid electrolyte layer 6 and the air electrode 8. When the element section 3 has an intermediate layer 7, the intermediate layer 7 makes it difficult for certain elements to diffuse. For example, if elements such as Sr (strontium) contained in the air electrode 8 diffuse into the solid electrolyte layer 6, a resistive phase such as SrZrO3 will be formed in the solid electrolyte layer 6. The intermediate layer 7 makes it difficult for compounds such as SrZrO3 to form by making it difficult for certain elements such as Sr to diffuse.

[0034] The material of the intermediate layer 7 is not particularly limited as long as it generally prevents the diffusion of elements between the air electrode 8 and the solid electrolyte layer 6. The material of the intermediate layer 7 may, for example, contain cerium oxide (CeO2) in which rare earth elements other than Ce (cerium) are dissolved. Such rare earth elements may include Gd (gadolinium) or Sm (samarium).

[0035] <Details of the electrochemical cell> Next, the details of the electrochemical cell according to this embodiment will be further explained with reference to Figures 1A and 2. Figure 2 is an enlarged cross-sectional view of region R1 shown in Figure 1A.

[0036] The solid electrolyte layer 6 is located between the fuel electrode 5 and the air electrode 8. As shown in Figure 2, the solid electrolyte layer 6 has a first surface 61 and a second surface 62 located at both ends in the thickness direction T. The first surface 61 is in contact with the fuel electrode 5. The second surface 62 is in contact with the intermediate layer 7. The second surface 62 may also be in contact with the air electrode 8.

[0037] The solid electrolyte layer 6 contains a plurality of pores 60. The porosity of the solid electrolyte layer 6 may be, for example, 3 area% to 15 area%.

[0038] The pores 60 include a first pore 60a. The first pore 60a is a pore 60 having a major axis extending in a direction along the first surface 61. When a pore 60 is said to have a major axis extending in a direction along the first surface 61, it means that when the angle between the major axis of the pore 60 and the first surface 61 is θ, -45° ≤ θ ≤ 45°. Note that if the major axis of the pore 60 and the first surface 61 are parallel, θ = 0°. Also, if the major axis of the pore 60 and the first surface 61 are perpendicular, θ = ±90°. Note that the major axis here refers to the direction in which the major axis of the pore 60 extends.

[0039] Furthermore, the first pore 60a is flattened. Specifically, a pore 60 with an aspect ratio of 2 or more is called a flattened pore 60. The aspect ratio of a pore 60 is calculated as D / d, where D is the major axis and d is the minor axis of the pore 60. The major axis of the pore 60 may be, for example, 0.25 μm to 0.7 μm. The minor axis of the pore 60 may be, for example, 0.05 μm to 0.25 μm.

[0040] As shown in Figure 2, in a cross-section along the thickness direction T of the solid electrolyte layer 6, the first area ratio, which is the area ratio occupied by the first pores 60a, is 2% or more and 10% or less.

[0041] Thus, when the first area ratio is between 2% and 10%, the gas barrier properties of the solid electrolyte layer 6 are maintained. Furthermore, even if a crack occurs inside the solid electrolyte layer 6, the crack reaches the first pore 60a, making further crack propagation difficult. For this reason, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less prone to strength reduction, thereby improving durability.

[0042] Furthermore, the distribution of the first pores 60a in the solid electrolyte layer 6 may differ depending on the location. The solid electrolyte layer 6 may be divided into a first section 6a including a first surface 61, a second section 6b including a second surface 62, and a third section 6c located between the first section 6a and the second section 6b. When the thickness of the solid electrolyte layer 6 is t, the first section 6a can be a section where the distance from the first surface 61 is 20% or less of t. The second section 6b can be a section where the distance from the second surface 62 is 20% or less of t.

[0043] In a cross-section along the thickness direction T, the solid electrolyte layer 6 may have a first area ratio in the third portion 6c that is greater than the first area ratio in the first portion 6a and / or the second portion 6b.

[0044] Tensile stress associated with oxidation and reduction of cell 1 tends to occur near the surface of the solid electrolyte layer 6, close to the first surface 61 and / or the second surface 62. The first pore 60a located in the third area 6c is less likely to become a fracture initiation point compared to the first pore 60a located in the first area 6a and / or the second area 6b, while also making it less likely for cracks to propagate inside the solid electrolyte layer 6. Therefore, according to the solid electrolyte layer 6 and cell 1 equipped therewith in this embodiment, the strength is less likely to decrease further, thereby further improving durability.

[0045] The first pores 60a may include second pores 60b. The second pores 60b are pores 60 of the first pores 60a having an aspect ratio of 3 to 10. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the second area ratio, which is the area ratio occupied by the second pores 60b, may be 30% to 50% of the first area ratio. This makes it easier for cracks to reach the first pores 60a even if cracks occur inside the solid electrolyte layer 6, further crack propagation is less likely to occur. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to decrease in strength, and thus durability is further improved.

[0046] Here, the arrangement and shape of the pores 60 in the solid electrolyte layer 6 can be obtained as follows. For example, the polished cross-section of the cell 1 containing the solid electrolyte layer 6 can be measured by image analysis using an SEM (scanning electron microscope). Specifically, the cell 1 is cut at any point containing the solid electrolyte layer 6 in a direction perpendicular to the first surface 61 and / or the second surface 62 to obtain a cut piece. The obtained cut piece is embedded in resin and polished to obtain a cross-section along the thickness direction of the solid electrolyte layer 6. The arrangement and shape of the pores 60 in the solid electrolyte layer 6 can be confirmed by observing the obtained cross-section using an SEM or the like. For example, a cross-sectional image including the first surface 61 and / or the second surface 62 can be taken using an SEM at a magnification of 10,000x, and the arrangement and shape of the pores 60 can be confirmed by image analysis of the obtained cross-sectional image.

[0047] The major and minor axes of the pores 60 can be calculated based on cross-sectional images of the solid electrolyte layer 6. The major axis of the pores 60 is the largest Ferret diameter among the Ferret diameters of the pores 60 viewed in cross-section. The minor axis of the pores 60 is the smallest Ferret diameter. Furthermore, the direction in which the major axis of the pores 60 extends can also be determined based on the shape of the pores 60 viewed in cross-section. The first and second area ratios are obtained by identifying the first pores 60a and the second pores 60b based on the arrangement and shape of the pores 60 confirmed by image analysis, and then performing further image analysis. The first area ratio, the second area ratio, and the ratio of the second area ratio to the first area ratio can be determined by evaluating the average value of each value calculated from each cross-sectional image.

[0048] The shape of the pores 60 in the solid electrolyte layer 6 can be adjusted, for example, by changing the shape of a known pore-forming material added to the material of the solid electrolyte layer 6. Furthermore, the arrangement of the first pores 60a can be adjusted, for example, by appropriately changing the fluidity of the material of the solid electrolyte layer 6 or the timing of adding the pore-forming material to the material of the solid electrolyte layer 6. However, there are no restrictions on the manufacturing method of the solid electrolyte layer 6 having the first pores 60a; it may be manufactured by any method.

[0049] <Configuration of an electrochemical cell system> Next, the electrochemical cell apparatus according to this embodiment using the cell 1 described above will be explained with reference to Figures 3A to 3C. Figure 3A is a perspective view showing an example of the electrochemical cell apparatus according to the first embodiment. Figure 3B is a cross-sectional view taken along line XX shown in Figure 3A. Figure 3C is a top view showing an example of the electrochemical cell apparatus according to the first embodiment.

[0050] As shown in Figure 3A, the cell stacking device 10 comprises a cell stack 11 having a plurality of cells 1 arranged (stacked) in the thickness direction T (see Figure 1A) of the cell 1, and a fixing member 12.

[0051] The fixing member 12 includes 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 includes a support body 15 and a gas tank 16. The support body 15 and the gas tank 16, which make up the support member 14, are made of, for example, metal.

[0052] As shown in Figure 3B, the support 15 has an insertion hole 15a into which the lower ends of the multiple cells 1 are inserted. The lower ends of the multiple cells 1 and the inner wall of the insertion hole 15a are joined together by a fixing member 13.

[0053] The gas tank 16 has an opening that supplies reaction gas to multiple cells 1 through an insertion hole 15a, and a groove 16a located around the opening. The outer end of the support 15 is joined to the gas tank 16 by a bonding material 21 that is filled into the groove 16a of the gas tank 16.

[0054] In the example shown in Figure 3A, fuel gas is stored in the internal space 22 (see Figure 3B) formed by the support member 14, which is the support 15, and the gas tank 16. A gas flow pipe 20 is connected to the gas tank 16. Fuel gas is supplied to the gas tank 16 through this gas flow pipe 20 and then supplied from the gas tank 16 to the gas flow path 2a (see Figure 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated in the reformer 102 (see Figure 4), which will be described later.

[0055] Hydrogen-rich fuel gas can be produced by steam reforming of the raw fuel. When fuel gas is produced by steam reforming, the fuel gas contains water vapor.

[0056] The example shown in Figure 3A includes two rows of cell stacks 11, two support members 15, and a gas tank 16. Each of the two rows of cell stacks 11 has multiple cells 1. Each cell stack 11 is fixed to each support member 15. The gas tank 16 has two through holes on its top surface. Each support member 15 is placed in each through hole. The internal space 22 is formed by one gas tank 16 and two support members 15. The cell stack device 10 may have only one cell stack 11, or it may have three or more cell stacks 11.

[0057] The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. The length of the insertion hole 15a in the arrangement direction of the cell 1, i.e., the thickness direction T, may be greater than the distance between the two end current collectors 17 located at both ends of the cell stack 11. The width of the insertion hole 15a may be, for example, greater than the length in the width direction W (see Figure 1A) of the cell 1.

[0058] As shown in Figure 3B, the joint between the inner wall of the insertion hole 15a and the lower end of the cell 1 is filled with a fixing material 13 and solidified. This joins and fixes the inner wall of the insertion hole 15a to the lower ends of the multiple cells 1, and also joins and fixes the lower ends of the cells 1 to each other. The gas passage 2a of each cell 1 communicates with the internal space 22 of the support member 14 at its lower end.

[0059] The fixing material 13 and the bonding material 21 can be made of materials with low conductivity, such as glass. Specific materials for the fixing material 13 and the bonding material 21 may include amorphous glass, and in particular, crystallized glass may be used.

[0060] As the crystallized glass, any of the following materials may be used, for example: SiO2-CaO system, MgO-B2O3 system, La2O3-B2O3-MgO system, La2O3-B2O3-ZnO system, SiO2-CaO-ZnO system, and in particular, SiO2-MgO system materials may be used.

[0061] Furthermore, as shown in Figure 3B, a connecting member 18 is interposed between adjacent cells 1 among the multiple cells 1. The connecting member 18 electrically connects the fuel electrode 5 of one adjacent cell 1 to the air electrode 8 of the other cell 1 in series. More specifically, the connecting member 18 connects the interconnector 4, which is electrically connected to the fuel electrode 5 of one adjacent cell 1, to the air electrode 8 of the other cell 1.

[0062] Furthermore, as shown in Figure 3B, the end current collector 17 is electrically connected to the outermost cell 1 in the arrangement direction of the multiple cells 1. The end current collector 17 is connected to a conductive part 19 that protrudes to the outside of the cell stack 11. The conductive part 19 collects the electricity generated by the cell 1 and draws it out to the outside. Note that the end current collector 17 is not shown in Figure 3A.

[0063] Furthermore, as shown in Figure 3C, the cell stack device 10 may be a single battery in which two cell stacks 11A and 11B are connected in series. In this case, the conductive part 19 of the cell stack device 10 is distinguished into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0064] The positive terminal 19A is the positive terminal when the power generated by the cell stack 11 is output to the outside. The positive terminal 19A is electrically connected to the positive terminal end current collector 17 of the cell stack 11A. The negative terminal 19B is the negative terminal when the power generated by the cell stack 11 is output to the outside. The negative terminal 19B is electrically connected to the negative terminal end current collector 17 of the cell stack 11B.

[0065] The connection terminal 19C electrically connects the negative terminal end current collector 17 of the cell stack 11A to the positive terminal end current collector 17 of the cell stack 11B.

[0066] <module> Next, a module according to the embodiment of this disclosure using the electrochemical cell apparatus described above will be explained with reference to Figure 4. Figure 4 is an external perspective view showing an example of a module according to the first embodiment. In Figure 4, the front and rear surfaces, which are part of the storage container 101, have been removed, and the fuel cell cell stack device 10 housed inside has been taken out to the rear.

[0067] As shown in Figure 4, module 100 comprises a cell stacking device 10 and a storage container 101 that houses the cell stacking device 10. A reformer 102 is positioned above the cell stacking device 10.

[0068] The reformer 102 reforms raw fuels such as natural gas and kerosene to produce fuel gas, which is then supplied to cell 1. The raw fuels are supplied to the reformer 102 through a raw fuel supply pipe 103. The reformer 102 may also include a vaporization section 102a for vaporizing water and a reforming section 102b. The reforming section 102b is equipped with a reforming catalyst (not shown) and reforms the raw fuels into fuel gas. Such a reformer 102 can perform steam reforming, which is a highly efficient reforming reaction.

[0069] The fuel gas generated in the reformer 102 is then supplied to the gas flow path 2a of cell 1 (see Figure 1A) through the gas flow pipe 20, the gas tank 16, and the support member 14.

[0070] Furthermore, in the module 100 with the above configuration, the temperature inside the module 100 during normal power generation is approximately 500°C to 1000°C due to the combustion of gas and the power generation of cell 1.

[0071] In such a module 100, as described above, the module 100 can be made more durable by housing a cell stack device 10 having a cell 1 with improved durability.

[0072] <Module housing device> Figure 5 is a schematic 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 comprises an outer case 111, a module 100 shown in Figure 4, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The outer case 111 houses the module 100 and the auxiliary equipment. Note that some components are omitted in Figure 5.

[0073] The outer casing 111 of the module housing device 110 shown in Figure 5 has support columns 112 and outer panels 113. Partition plates 114 divide the inside of the outer casing 111 into upper and lower sections. The space above the partition plates 114 inside the outer casing 111 is the module housing chamber 115 for housing the module 100, and the space below the partition plates 114 inside the outer casing 111 is the auxiliary equipment housing chamber 116 for housing auxiliary equipment configured to operate the module 100. Note that in Figure 5, the auxiliary equipment housed in the auxiliary equipment housing chamber 116 is omitted from the illustration.

[0074] Furthermore, the partition plate 114 has an air circulation port 117 for allowing air from the auxiliary equipment storage room 116 to flow towards the module storage room 115. The outer panel 113 that constitutes the module storage room 115 has an exhaust port 118 for exhausting the air inside the module storage room 115.

[0075] In such a module housing device 110, as described above, by providing a module 100 with improved durability in the module housing chamber 115, the module housing device 110 can be made more durable.

[0076] In the above embodiment, a case using a hollow flat support substrate was illustrated, but it can also be applied to a cell stacking device using a cylindrical support substrate.

[0077] [Second Embodiment] Next, the electrochemical cell and electrochemical cell apparatus according to the second embodiment will be described with reference to Figures 6A to 7.

[0078] In the above-described embodiment, a so-called "vertical stripe type" was exemplified, in which only one element section including a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the surface of the support substrate. However, this can also be applied to a horizontal stripe type electrochemical cell apparatus in which a so-called "horizontal stripe type" electrochemical cell is arranged, in which element sections are provided at multiple locations on the surface of the support substrate that are far apart from each other, and adjacent element sections are electrically connected.

[0079] Figure 6A is a cross-sectional view showing an example of an electrochemical cell apparatus according to the second embodiment. Figure 6B is a transverse cross-sectional view showing an electrochemical cell according to the second embodiment. Figure 7 is an enlarged cross-sectional view of region R2 shown in Figure 6B.

[0080] As shown in Figure 6A, the cell stack device 10A has multiple cells 1 extending in the longitudinal direction L from a pipe 22a through which fuel gas flows. Each cell 1 has multiple element sections 3 on a support substrate 2. Inside the support substrate 2, there is a gas passage 2a through which the fuel gas from the pipe 22a flows.

[0081] Furthermore, each cell 1 is electrically connected to one another via a connecting member 31. The connecting member 31 is located between the element portions 3 of each cell 1 and connects adjacent cells 1.

[0082] Furthermore, as shown in Figure 6B, the cell 1 according to this embodiment comprises a support substrate 2, a pair of element portions 3A, and a sealing portion 32. The support substrate 2 is columnar in shape, having a pair of opposing flat surfaces n1 and n2, and a pair of arc-shaped side surfaces m connecting surfaces n1 and n2.

[0083] The pair of element portions 3A are located on surfaces n1 and n2 of the support substrate 2, respectively. The sealing portion 32 is positioned to cover the side surface m of the support substrate 2.

[0084] The electrochemical cell according to this embodiment has an element section 3A. The element section 3A includes a solid electrolyte layer 6, a fuel electrode 5, and an air electrode 8. The element section 3A may also have an intermediate layer 7 located between the solid electrolyte layer 6 and the air electrode 8.

[0085] As shown in Figure 7, the solid electrolyte layer 6 is located between the fuel electrode 5 and the air electrode 8. The solid electrolyte layer 6 contains a plurality of pores 60.

[0086] The pores 60 include first pores 60a. The first pores 60a have a major axis extending in the direction along the first surface 61 and are flattened pores 60. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the first area ratio, which is the area ratio occupied by the first pores 60a, is 2% or more and 10% or less.

[0087] Thus, when the first area ratio is between 2% and 10%, the gas barrier properties of the solid electrolyte layer 6 are maintained. Furthermore, even if a crack occurs inside the solid electrolyte layer 6, the crack reaches the first pore 60a, making further crack propagation difficult. For this reason, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less prone to strength reduction, thereby improving durability.

[0088] Furthermore, in a cross-section along the thickness direction T, the first area ratio in the third portion 6c of the solid electrolyte layer 6 may be greater than the first area ratio in the first portion 6a and / or the second portion 6b. This makes it less likely for the first pore 60a to become a fracture initiation point of the solid electrolyte layer 6, and also makes it less likely for cracks to propagate inside the solid electrolyte layer 6. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to experience further strength degradation, thereby further improving durability.

[0089] The first pores 60a may also include second pores 60b. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the second area ratio, which is the area ratio occupied by the second pores 60b, may be 30% or more and 50% or less of the first area ratio. This makes it easier for cracks to reach the first pores 60a even if cracks occur inside the solid electrolyte layer 6, further crack propagation is less likely to occur. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to decrease in strength, and thus durability is further improved.

[0090] [Third Embodiment] Figure 8A is a perspective view showing an example of an electrochemical cell according to the third embodiment. Figure 8B is a partial cross-sectional view of the electrochemical cell shown in Figure 8A.

[0091] As shown in Figures 8A and 8B, cell 1 has an element section 3B in which a fuel electrode 5, a solid electrolyte layer 6, and an air electrode 8 are stacked in order, and conductive members 91 and 92 positioned to sandwich both ends of the element section 3B. The element section 3B may also have an intermediate layer 7 located between the solid electrolyte layer 6 and the air electrode 8. In an electrochemical cell apparatus in which multiple planar cells are stacked, for example, multiple cells 1 are electrically connected by conductive members 91 and 92, which are adjacent metal layers. The conductive members 91 and 92 electrically connect adjacent cells 1 to each other and also have gas channels for supplying gas to the fuel electrode 5 or the air electrode 8.

[0092] As shown in Figure 8B, cell 1 has a sealing material that hermetically seals the fuel gas flow path and the oxygen-containing gas flow path of the flat-plate cell stack. The sealing material is a fixing member 96 of cell 1 and has a joining member 93 and support members 94 and 95 which are frames. The joining member 93 may be glass or a metal material such as silver solder.

[0093] The support member 94 may be a so-called separator that divides the fuel gas flow path from the oxygen-containing gas flow path. The material of the support members 94 and 95 may be, for example, a conductive metal or an insulating ceramic. Both or one of the support members 94 and 95 may be made of an insulating material. If the support member 94 is made of metal, it may be integrated with the conductive member 92. If the support member 95 is made of metal, it may be integrated with the conductive member 91.

[0094] Figure 9 is an enlarged cross-sectional view of region R3 shown in Figure 8B. As shown in Figure 9, the solid electrolyte layer 6 is located between the fuel electrode 5 and the air electrode 8. The solid electrolyte layer 6 contains a plurality of pores 60.

[0095] The pores 60 include first pores 60a. The first pores 60a have a major axis extending in the direction along the first surface 61 and are flattened pores 60. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the first area ratio, which is the area ratio occupied by the first pores 60a, is 2% or more and 10% or less.

[0096] Thus, when the first area ratio is between 2% and 10%, the gas barrier properties of the solid electrolyte layer 6 are maintained. Furthermore, even if a crack occurs inside the solid electrolyte layer 6, the crack reaches the first pore 60a, making further crack propagation difficult. For this reason, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less prone to strength reduction, thereby improving durability.

[0097] Furthermore, in a cross-section along the thickness direction T, the first area ratio in the third portion 6c of the solid electrolyte layer 6 may be greater than the first area ratio in the first portion 6a and / or the second portion 6b. This makes it less likely for the first pore 60a to become a fracture initiation point of the solid electrolyte layer 6, and also makes it less likely for cracks to propagate inside the solid electrolyte layer 6. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to experience further strength degradation, thereby further improving durability.

[0098] The first pores 60a may also include second pores 60b. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the second area ratio, which is the area ratio occupied by the second pores 60b, may be 30% or more and 50% or less of the first area ratio. This makes it easier for cracks to reach the first pores 60a even if cracks occur inside the solid electrolyte layer 6, further crack propagation is less likely to occur. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to decrease in strength, and thus durability is further improved.

[0099] [Fourth Embodiment] Figure 10A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. Figures 10B and 10C are cross-sectional views showing other examples of the electrochemical cell according to the fourth embodiment. Figure 11 is an enlarged cross-sectional view of region R4 shown in Figure 10A. Note that Figure 11 can also be applied to the electrochemical cells shown in Figures 10B and 10C.

[0100] As shown in Figures 10A to 10C, cell 1 has an element section 3C and a support substrate 2. The support substrate 2 has through holes or pores in the portion in contact with the element section 3C, and also has 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 plates may contain chromium. The metal plates may have a conductive coating layer. The support substrate 2 electrically connects adjacent cells 1 to each other. The element section 3C may be formed directly on the support substrate 2, or it may be joined to the support substrate 2 by a bonding material.

[0101] Furthermore, cell 1 may have an adhesive (not shown) located between the fuel electrode 5 and the support substrate 2. The adhesive joins the element portion 3C to the support substrate 2 and fixes the element portion 3C to the support substrate 2.

[0102] The adhesive may be conductive. The adhesive may contain, for example, conductive particles such as Ni and inorganic oxides such as TiO2, rare earth element oxides (Y2O3, CeO2, etc.), and transition metal oxides (Fe2O3, CuO, etc.). The adhesive may also contain metal particles and conductive oxide particles.

[0103] The adhesive may be gas permeable. If the adhesive is gas permeable, it may be positioned to cover the through holes or pores in the support substrate 2.

[0104] The adhesive may consist of a single layer made of a single material, or it may consist of a laminate made by layering multiple materials.

[0105] Furthermore, cell 1 may have a restraining layer (not shown). The restraining layer is located between the element portion 3C and the adhesive. The restraining layer works in cooperation with the solid electrolyte layer 6 to prevent warping or bending of the element portion 3C.

[0106] The material of the constraining layer exhibits a shrinkage rate similar to that of the solid electrolyte layer 6 during firing. The material of the constraining layer may be the same as that of the solid electrolyte layer 6. The element 3C obtained by sandwiching the fuel electrode 5 material of the element 3C between the solid electrolyte layer 6 material and the constraining layer material and firing it exhibits reduced warping or deformation.

[0107] The restraining layer may or may not be gas permeable. If the restraining layer has gas barrier properties similar to those of the solid electrolyte layer 6, the restraining layer can be partially positioned so as not to obstruct the inflow of fuel gas to the fuel electrode 5.

[0108] Cell 1 may also have a gas diffusion layer (not shown). The gas diffusion layer is located between the fuel electrode 5 and the support substrate 2. The gas diffusion layer is gas permeable and allows the fuel gas flowing through the gas channel 2a to permeate to the fuel electrode 5. The open porosity of the gas diffusion layer may be, for example, in the range of 30% to 50%, particularly 35% to 45%.

[0109] The material for the gas diffusion layer may be a porous conductive ceramic, such as a ceramic containing calcium oxide, magnesium oxide, or stabilized or partially stabilized zirconia in which a rare earth element oxide is in solid solution, and Ni and / or NiO. This rare earth element oxide may contain, for example, multiple rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0110] In the example shown in Figure 10A, the side surface of the fuel electrode 5 is covered with a solid electrolyte layer 6, hermetically sealing the gas passage 2a through which the fuel gas flows. As shown in Figure 10B, the side surface of the fuel electrode 5 may also be covered and sealed with a dense glass or ceramic sealant 9. The sealant 9 covering the side surface of the fuel electrode 5 may have electrical insulating properties.

[0111] Furthermore, the gas flow path 2a of the support substrate 2 may be formed by a member 120 having irregularities, as shown in Figure 10C.

[0112] The electrochemical cell according to this embodiment has an element section 3C. The element section 3C has a solid electrolyte layer 6, a fuel electrode 5, and an air electrode 8. The element section 3C may also have an intermediate layer 7 located between the solid electrolyte layer 6 and the air electrode 8.

[0113] As shown in Figure 11, the solid electrolyte layer 6 is located between the fuel electrode 5 and the air electrode 8. The solid electrolyte layer 6 contains a plurality of pores 60.

[0114] The pores 60 include first pores 60a. The first pores 60a have a major axis extending in the direction along the first surface 61 and are flattened pores 60. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the first area ratio, which is the area ratio occupied by the first pores 60a, is 2% or more and 10% or less.

[0115] Thus, when the first area ratio is between 2% and 10%, the gas barrier properties of the solid electrolyte layer 6 are maintained. Furthermore, even if a crack occurs inside the solid electrolyte layer 6, the crack reaches the first pore 60a, making further crack propagation difficult. For this reason, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less prone to strength reduction, thereby improving durability.

[0116] Furthermore, in a cross-section along the thickness direction T, the first area ratio in the third portion 6c of the solid electrolyte layer 6 may be greater than the first area ratio in the first portion 6a and / or the second portion 6b. This makes it less likely for the first pore 60a to become a fracture initiation point of the solid electrolyte layer 6, and also makes it less likely for cracks to propagate inside the solid electrolyte layer 6. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to experience further strength degradation, thereby further improving durability.

[0117] The first pores 60a may also include second pores 60b. In a cross-section along the thickness direction T of the solid electrolyte layer 6, the second area ratio, which is the area ratio occupied by the second pores 60b, may be 30% or more and 50% or less of the first area ratio. This makes it easier for cracks to reach the first pores 60a even if cracks occur inside the solid electrolyte layer 6, further crack propagation is less likely to occur. Therefore, the solid electrolyte layer 6 and the cell 1 equipped therewith according to this embodiment are less likely to decrease in strength, and thus durability is further improved.

[0118] [Other embodiments] In the embodiments described above, fuel cell cells, fuel cell stack devices, fuel cell modules, and fuel cell devices were shown as examples of "electrochemical cells," "electrochemical cell devices," "modules," and "module housing devices," but other examples may be electrolytic cells, electrolytic cell stack devices, electrolytic modules, and electrolytic devices, respectively. An electrolytic cell, for example, has an oxygen electrode as a first electrode and a hydrogen electrode as a second electrode, and decomposes water vapor into hydrogen and oxygen by supplying electricity. Alternatively, an electrolytic cell may decompose carbon dioxide into carbon monoxide and oxygen by supplying electricity. In addition, in each of the embodiments described above, oxide ion conductors or hydrogen ion conductors were shown as examples of electrolyte materials for electrochemical cells, but hydroxide ion conductors may also be used. Such electrolytic cells, electrolytic cell stack devices, electrolytic modules, and electrolytic devices can improve durability. Solid oxide type fuel cell cells and electrolytic cells are collectively referred to as solid oxide type electrochemical cells.

[0119] Although the present disclosure has been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0120] In one embodiment, (1) the solid electrolyte layer has a first surface and a second surface located at both ends in the thickness direction, and is a solid electrolyte layer containing a plurality of pores, The plurality of pores have a major axis extending in a direction along the first surface and include a flattened first pore, In the cross-section along the thickness direction, the first area ratio, which is the area ratio occupied by the first pore, is 2% or more and 10% or less.

[0121] (2) In the solid electrolyte layer described in (1) above, when the thickness of the solid electrolyte layer is t, The first part whose distance from the first surface is 20% or less of t, The second part, whose distance from the second surface is 20% or less of t, A third part located between the first and second parts and It has, In the cross-section, the first area ratio in the third portion may be greater than the first area ratio in the first portion and / or the second portion.

[0122] (3) In the solid electrolyte layer of (1) or (2) above, the first pore includes a second pore having an aspect ratio of 3 or more and 10 or less, In the cross-section, the second area ratio, which is the area ratio occupied by the second pore, may be 30% or more and 50% or less of the first area ratio.

[0123] In one embodiment, (4) the electrochemical cell comprises one of the solid electrolyte layers described in (1) to (3) above.

[0124] In one embodiment, (5) the electrochemical cell apparatus has a cell stack comprising the electrochemical cell described in (4) above.

[0125] In one embodiment, module (6) is an electrochemical cell apparatus of the above (5), The system includes a storage container that houses the aforementioned electrochemical cell apparatus.

[0126] In one embodiment, (7) the module housing device includes the module described in (6) above, An auxiliary device configured to operate the aforementioned module, The system comprises the module and an outer casing housing the auxiliary equipment.

[0127] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0128] 1 cell 3,3A~3C element part 5 Fuel electrode 6 Solid electrolyte layer 6a Part 1 6b 2nd part 6c 3rd part 7. Middle Class 8. Air pole 10-cell stack device 11-cell stack 60 Stomata 60a First stoma 60b Second Stomata 61 Page 1 62 2nd page 100 modules 110 Module housing device

Claims

1. A solid electrolyte layer having a first surface and a second surface located at both ends in the thickness direction, and containing a plurality of pores, The plurality of pores have a major axis extending in a direction along the first surface and include a flattened first pore, In the cross-section along the thickness direction, the first area ratio, which is the area ratio occupied by the first pore, is 2% or more and 10% or less. Solid electrolyte layer.

2. When the thickness of the solid electrolyte layer is t, The first part whose distance from the first surface is 20% or less of t, The second part is located at a distance of 20% or less of t from the second surface, A third part located between the first part and the second part and It has, In the cross-section, the first area ratio in the third portion is greater than the first area ratio in the first portion and / or the second portion. The solid electrolyte layer according to claim 1.

3. The first pore includes a second pore having an aspect ratio of 3 to 10. In the aforementioned cross-section, the second area ratio, which is the area ratio occupied by the second pore, is 30% or more and 50% or less of the first area ratio. The solid electrolyte layer according to claim 1.

4. The solid electrolyte layer is provided according to any one of claims 1 to 3. Electrochemical cell.

5. A cell stack comprising the electrochemical cell described in claim 4. Electrochemical cell apparatus.

6. The electrochemical cell apparatus according to claim 5, The storage container housing the aforementioned electrochemical cell apparatus and A module equipped with the following features.

7. The module according to claim 6, An auxiliary device configured to operate the aforementioned module, The outer casing housing the module and the auxiliary equipment A module housing device equipped with the following features.

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