Conductive porous member, electrochemical cell, electrochemical cell device, module, and module storage device

Abstract

This conductive porous member comprises metal particles and titanium oxide particles. The titanium oxide particles include first titanium oxide particles having a first part containing TiOx (0.5≤x≤1.95) in a surface layer portion at a distance of 30 nm or less from the particle surface.

Description

Conductive porous member, electrochemical cell, electrochemical cell apparatus, module, and module housing apparatus

[0001] This disclosure relates to conductive porous members, electrochemical cells, electrochemical cell devices, modules, and module housing devices.

[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.

[0003] International Publication No. 2020 / 218431

[0004] A conductive porous member according to one embodiment includes metal particles and titanium oxide particles. The titanium oxide particles have a surface layer at a distance of 30 nm or less from the particle surface containing TiO ｘ It contains a first titanium oxide particle in which a first region having (0.5 ≤ x ≤ 1.95) is located.

[0005] Furthermore, the electrochemical cell of this disclosure comprises a metal plate, an element portion, and an intermediate layer located between the metal plate and the element portion. The intermediate layer is the conductive porous member described above.

[0006] Furthermore, the electrochemical cell apparatus of this disclosure has a cell stack comprising the electrochemical cells described above.

[0007] Furthermore, the module of this disclosure comprises the electrochemical cell apparatus described above and a housing container that houses the electrochemical cell apparatus.

[0008] Furthermore, the module housing device of this disclosure comprises the module described above, an auxiliary device configured to operate the module, and an outer casing housing the module and the auxiliary device.

[0009] FIG. 1A is a plan view showing an example of an electrochemical cell according to an embodiment. FIG. 1B is a cross-sectional view showing an example of line A-A shown in FIG. 1A. FIG. 1C is a cross-sectional view showing another example of line A-A shown in FIG. 1A. FIG. 2A is a cross-sectional view schematically showing an example of a conductive porous member included in the electrochemical cell according to the embodiment. FIG. 2B is a cross-sectional view schematically showing an example of first titanium oxide particles included in the conductive porous member according to the embodiment. FIG. 3A is a perspective view showing an example of an electrochemical cell device according to the embodiment. FIG. 3B is a cross-sectional view of line X-X shown in FIG. 3A. FIG. 3C is a top view showing an example of the electrochemical cell device according to the embodiment. FIG. 4 is an external perspective view showing an example of a module according to the embodiment. FIG. 5 is an exploded perspective view schematically showing an example of a module housing device according to the embodiment.

[0010] In the above fuel cell stack device, for example, there was room for improvement in terms of improving power generation performance.

[0011] Therefore, there is an expectation for providing a conductive porous member, an electrochemical cell, an electrochemical cell device, a module, and a module housing device that can improve performance.

[0012] Hereinafter, embodiments of the conductive porous member, electrochemical cell, electrochemical cell device, module, and module housing device disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that this disclosure is not limited by the embodiments shown below.

[0013] Also, note that the drawings are schematic, and it is necessary to be aware that the dimensional relationships of each element, the ratios of each element, etc. may be different from reality. Furthermore, even between the drawings, there may be portions where the dimensional relationships, ratios, etc. of each other are different.

[0014] [Embodiment] <Configuration of Electrochemical Cell> First, with reference to FIGS. 1A to 1C, the electrochemical cell according to the embodiment will be described using an example of a solid oxide type 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 is simply referred to as a cell stack device.

[0015] Figure 1A is a plan view showing an example of an electrochemical cell according to the embodiment. Figure 1B is a cross-sectional view showing an example of the line A-A shown in Figure 1A. Figures 1A and 1B show enlarged views of some of the components of the electrochemical cell. Hereinafter, the electrochemical cell may simply be referred to as a cell.

[0016] For the sake of clarity, Figures 1A and 1B illustrate a three-dimensional Cartesian coordinate system including a Z-axis, where the vertically upward direction is positive and the vertically downward direction is negative. This Cartesian coordinate system may also be shown in other drawings used in the explanations below. Furthermore, components with the same reference numerals as those in the electrochemical cell shown in Figures 1A and 1B are used, and their explanations are omitted or simplified.

[0017] As shown in Figures 1A and 1B, the cell 1 according to this embodiment comprises an element section 3, a metal plate 23, and an intermediate layer 30. The element section 3 has a fuel electrode 5, a solid electrolyte layer 6, and an air electrode 8.

[0018] 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 is gas permeable. The open porosity of the fuel electrode 5 may be, for example, 30% or more and 50% or less, and particularly 35% or more and 45% or less. The open porosity of the fuel electrode 5 is sometimes referred to as the porosity or void ratio of the fuel electrode 5.

[0019] The fuel electrode 5 can be made of a material that is generally known. The fuel electrode 5 can be made of porous conductive ceramics, such as calcium oxide, magnesium oxide, or ZrO2 in which rare earth element oxides are in solid solution. ２ Furthermore, ceramics containing elemental Ni, namely metallic Ni and / or NiO, may be used. This rare earth element oxide may include, for example, multiple rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or ZrO containing a solid solution of rare earth element oxides may also be used. ２ This is sometimes referred to as stabilized zirconia. Stabilized zirconia may include partially stabilized zirconia. The fuel electrode 5 is CeO in which La, Nd or Yb is in solid solution. ２ It may include.

[0020] 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 fuel gas and oxygen-containing gas to leak.

[0021] The material of the solid electrolyte layer 6 may be, for example, ZrO in which 3 mol% or more and 15 mol% or less of rare earth element oxide is dissolved. ２ It may be. 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 contain, for example, ZrO in which Yb, Sc or Gd is dissolved. ２ The solid electrolyte layer 6 may contain, for example, CeO in which La, Nd or Yb is dissolved. ２ The solid electrolyte layer 6 may contain, for example, BaZrO in which Sc or Yb is dissolved. ３ The solid electrolyte layer 6 may contain, for example, BaCeO in which Sc or Yb is dissolved. ３ It may be.

[0022] The air electrode 8 is a first electrode in contact with the oxygen-containing gas. The air electrode 8 has gas permeability. The open porosity of the air electrode 8 may be, for example, 20% or more and 50% or less, and particularly may be 30% or more and 50% or less. When the open porosity of the air electrode 8 is referred to as the porosity of the air electrode 8.

[0023] The material of the air electrode 8 is not particularly limited as long as it is generally used for air electrodes. The material of the air electrode 8 may be, for example, conductive ceramics such as so-called ABO ３ type perovskite oxides.

[0024] The material of the air electrode 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. Examples of such composite oxides include La ｘ Sr １－ｘ Co ｙ Fe １－ｙ O ３ 、La ｘ Sr １－ｘ MnO ３ 、La ｘ Sr １－ｘ FeO３ La ｘ Sr １－ｘ CoO ３ These are some examples. Note that x is 0 < x < 1 and y is 0 < y < 1.

[0025] Furthermore, the element portion 3 may have a diffusion suppression layer 7 located between the solid electrolyte layer 6 and the air electrode 8. When the element portion 3 has a diffusion suppression layer 7, the diffusion suppression layer 7 makes it difficult for specific elements to diffuse. For example, when a specific element such as Sr (strontium) contained in the air electrode 8 diffuses into the solid electrolyte layer 6, SrZrO, which has high electrical resistance, will be released into the solid electrolyte layer 6. ３ The resistive phase, such as Sr, is more likely to form. The diffusion-suppressing layer 7 makes it difficult for specific elements such as Sr to diffuse, so that SrZrO is formed in the solid electrolyte layer 6. ３ This makes it difficult for compounds with high electrical resistance, such as those mentioned above, to form.

[0026] The material of the diffusion-suppressing layer 7 is not particularly limited as long as it generally makes it difficult for elements to diffuse between the air electrode 8 and the solid electrolyte layer 6. The material of the diffusion-suppressing layer 7 may be, for example, cerium oxide (CeO2) in which rare earth elements other than Ce (cerium) are solid-solved. ２ ) may also be included. Examples of such rare earth elements include Gd (gadolinium) and Sm (samarium).

[0027] The metal plate 23 has surfaces 231 and 232 located at both ends in the thickness direction (Y-axis direction). Surface 231 is positioned facing the intermediate layer 30. Surface 232 is positioned on the opposite side of surface 231.

[0028] The metal plate 23 may be conductive. The metal plate 23 may also be a metal component containing, for example, chromium. The metal plate 23 may be, for example, a stainless steel such as a heat-resistant ferritic stainless steel or austenitic stainless steel. The metal plate 23 may also be, for example, a nickel-chromium alloy or an iron-chromium alloy. The metal plate 23 may also contain, for example, a metal oxide. Furthermore, the metal plate 23 may have a coating covering its surface. The metal plate 23 does not necessarily have a coating on its surface.

[0029] Furthermore, the metal plate 23 may have a plurality of through holes 23a. The through holes 23a penetrate between the surface 231 and the surface 232. The fuel gas flowing through the flow path 24, which will be described later, is supplied to the fuel electrode 5 of the element section 3 through the through holes 23a. The diameter (opening diameter) of the through holes 23a may be, for example, 0.1 mm to 1.0 mm, and particularly 0.3 mm to 0.6 mm. The opening ratio in the region where the through holes 23a are formed in the metal plate 23 viewed in plan along the Y-axis direction may be, for example, 10% or more. The metal plate 23 may have a coating covering the wall surface of the through holes 23a. The metal plate 23 does not have to have a coating on the wall surface of the through holes 23a.

[0030] The metal plate 23 may, for example, be gas permeable. If the metal plate 23 is gas permeable, it does not need to have through holes 23a.

[0031] The intermediate layer 30 is located between the element portion 3 and the metal plate 23. The intermediate layer 30 is located between the surface 231 of the metal plate 23 and the fuel electrode 5. The intermediate layer 30 is, for example, electrically conductive. The intermediate layer 30 is, for example, gas permeable. The intermediate layer 30 may be, for example, a conductive porous member 30A according to the embodiment. Details of the conductive porous member 30A will be described later.

[0032] Cell 1 may also have a flow path member 25. The flow path member 25 may be located on the side of the metal plate 232. The flow path member 25 may be fixed and electrically joined, for example, by welding at the contact portion with the surface 232. The flow path member 25 may be fixed and electrically joined to the metal plate 23 with a conductive sealing material or brazing material. The space located between the metal plate 23 and the flow path member 25 may be a flow path 24 through which fuel gas flows. The fuel gas flowing through the flow path 24 may be supplied to the fuel electrode 5 by permeating through the metal plate 23. The metal plate 23 may have one or more protrusions projecting toward the flow path member 25.

[0033] The flow channel member 25 may be further fixed to the current collector member 27 by welding or the like, and electrically joined. The current collector member 27 may be fixed to the flow channel member 25 with a conductive adhesive or brazing material, and electrically joined. The current collector member 27 may be fixed to the air electrode 8 of an adjacent cell 1 via an adhesive (not shown), and electrically joined. The space located between the current collector member 27 and the flow channel member 25 may be a flow channel 26 through which oxygen-containing gas flows. The oxygen-containing gas flowing through the flow channel 26 may be supplied to the air electrode 8 of the adjacent cell 1 via the slits and adhesive of the current collector member 27.

[0034] The material of the flow path member 25 and the current collector member 27 may be, for example, a dense metal or alloy. The flow path member 25 may be positioned to minimize leakage of the fuel gas flowing through the flow path 24 and the oxygen-containing gas flowing through the flow path 26. The flow path member 25 and the current collector member 27 may have a coating. For example, the surface of the flow path member 25 facing the flow path 24 may have a reduction-resistant coating, and the surface of the flow path member 25 facing the flow path 26 may have an oxidation-resistant coating. These coatings may be conductive.

[0035] Furthermore, as shown in Figure 1B, a sealing material 9 different from the solid electrolyte layer 6 may be located on the side surface of the element portion 3. The material of the sealing material 9 may be dense glass or ceramic. The material of the sealing material 9 may be, for example, amorphous glass or crystallized glass. As for crystallized glass, for example, SiO ２ -CaO system, MgO-B ２ O ３ System, La ２ O ３ -B ２ O ３ - MgO system, La ２ O ３ -B ２ O ３ - ZnO system, SiO ２ Any of the following materials may be used, particularly SiO ２-MgO-based materials may be used. The encapsulant 9 may have electrical insulating properties. Also, the material of the encapsulant 9 may be the same as the material of the solid electrolyte layer 6.

[0036] The sealing material 9 may be positioned to surround the side surface of the element portion 3. Alternatively, the surface of the intermediate layer 30 that is not in contact with the metal plate 23 and the element portion 3 may be covered with the sealing material 9. Furthermore, the sealing material 9 may be located on the side surface of the metal plate 23. Also, the sealing material 9 may be located on the side surface of the flow path member 25.

[0037] Furthermore, cell 1 may have a restraining layer (not shown). The restraining layer may be located between the element portion 3 and the intermediate layer 30. The restraining layer cooperates with the solid electrolyte layer 6 to prevent warping, bending, etc., of the element portion 3.

[0038] The material of the constraining layer may exhibit a shrinkage rate similar to that of the solid electrolyte layer 6 during firing. The material of the constraining layer may have a similar or identical composition to that of the solid electrolyte layer 6. The element 3 obtained by sandwiching the fuel electrode 5 material of the element 3 between the solid electrolyte layer 6 material and the constraining layer material and firing it will have reduced warping or deformation.

[0039] 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.

[0040] Furthermore, cell 1 may have a gas diffusion layer, which is not shown. The gas diffusion layer may be located between the fuel electrode 5 and the intermediate layer 30. The gas diffusion layer may be gas permeable so as to allow the fuel gas flowing through the channel 24 to pass through to the fuel electrode 5. The open porosity of the gas diffusion layer may be, for example, 30% or more and 50% or less, and particularly 35% or more and 45% or less.

[0041] The material for the gas diffusion layer may be a porous conductive ceramic, such as a ceramic containing stabilized or partially stabilized zirconia in which calcium oxide, magnesium oxide, or rare earth element oxides are solid-solved, and metallic Ni and / or NiO. These rare earth element oxides may include, for example, a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0042] Note that the shapes of the flow path member 25 and the current collector member 27 are not limited to those shown in Figure 1B. The flow path member 25 and the current collector member 27 may have any shape as long as they electrically connect adjacent cells 1 and make it difficult for fuel gas and oxygen-containing gas to leak.

[0043] Figure 1C is a cross-sectional view showing another example of the line A-A shown in Figure 1A. As shown in Figure 1C, the flow path member 25 may be integrated with the current collector member 27 and have a first protrusion that protrudes toward the adjacent cell 1 along the Y-axis direction and a second protrusion that protrudes toward the opposite side of the first protrusion.

[0044] <Configuration of the Conductive Porous Member> Next, the configuration of the conductive porous member of the electrochemical cell according to this embodiment will be described with reference to Figures 2A to 2B. Figure 2A is a schematic cross-sectional view showing an example of the conductive porous member of the electrochemical cell according to this embodiment.

[0045] The conductive porous member 30A according to this embodiment includes metal particles 31 and titanium oxide particles 32. The titanium oxide particles 32 include first titanium oxide particles 35.

[0046] Figure 2B is a schematic cross-sectional view showing an example of first titanium oxide particles in a conductive porous member according to the embodiment. The first titanium oxide particles 35 have a surface layer 35a containing TiO ｘ This is a titanium oxide particle 32 in which a first region 37 having (0.5 ≤ x ≤ 1.95) is located.

[0047] The surface layer 35a refers to the portion of the first titanium oxide particle 35 that is 30 nm or less in distance from the surface 350, which is the particle surface. ｘ (0.5 ≤ x ≤ 1.95) is TiO２ It has higher conductivity compared to [another material]. Therefore, by having the first portion 37 on the surface layer 35a of the first titanium oxide particles 35, the conductivity of the first titanium oxide particles 35 is improved compared to the case where the surface layer 35a does not have the first portion 37. In addition, by having the first portion 37 on the surface layer 35a of the first titanium oxide particles 35, conductive paths are more easily formed on the surface 350 and / or its vicinity, and the electrical resistance of the entire conductive porous member 30A is reduced. Cell 1 with such a conductive porous member 30A arranged as an intermediate layer 30 has improved power generation performance.

[0048] In the first titanium oxide particles 35, the occupancy ratio of the first portion 37 may be 1% or more and 20% or less. This makes it easier for conductive paths to be formed on and / or near the surface 350, and further reduces the electrical resistance of the entire conductive porous member 30A. A cell 1 in which such a conductive porous member 30A is arranged as an intermediate layer 30 has further improved power generation performance.

[0049] Furthermore, the metal particles 31 may also include first metal particles 33 having a particle size of 0.5 μm or less. The first metal particles 33 may be in contact with the first titanium oxide particles 35. The first metal particles 33 contribute, for example, to the gas permeability of the conductive porous member 30A. The first metal particles 33 ensure the gas permeability of the conductive porous member 30A by, for example, hindering the growth of the titanium oxide particles 32, which include the first titanium oxide particles 35. Therefore, according to the conductive porous member 30A of this embodiment, gas permeability is improved compared to, for example, the case without the first metal particles 33.

[0050] The first metal particle 33 may, for example, be in contact with the surface 350 of the first titanium oxide particle 35. The first metal particle 33 may be located inside the first titanium oxide particle 35, as shown in Figure 2B. When the first metal particle 33 is located inside the first titanium oxide particle 35, the first titanium oxide particle 35 has TiO in its portion 35b. ｘ A first portion 37 having (0.5 ≤ x ≤ 1.95) may be located there.

[0051] Part 35b refers to the portion of the first titanium oxide particles 35 that is 30 nm or less in distance from the boundary 352 with the first metal particles 33 located inside the first titanium oxide particles 35. The boundary 352 may include, for example, voids or other portions that are not in contact with the first metal particles 33.

[0052] By having the first portion 37 in portion 35b, the conductivity of the first titanium oxide particles 35 is improved compared to the case where the first portion 37 is not present in portion 35b. Furthermore, by having the first portion 37 in portion 35b, the electrical resistance of the entire conductive porous member 30A is reduced. A cell 1 in which such a conductive porous member 30A is arranged as an intermediate layer 30 exhibits further improved power generation performance.

[0053] Returning to Figure 2A, let's explain further. The conductive porous member 30A may contain 10% to 40% of first metal particles 33 relative to the total amount of metal particles 31. A cell 1 in which such a conductive porous member 30A is arranged as an intermediate layer 30 will have further improved power generation performance.

[0054] If the proportion of the first metal particles 33 in the metal particles 31 is less than 10%, for example, the electrical resistance of the entire conductive porous member 30A may not decrease sufficiently, making it difficult to improve power generation performance. Also, if the proportion of the first metal particles 33 in the metal particles 31 exceeds 40%, for example, the conductivity of the entire conductive porous member 30A may decrease, making it difficult to obtain the desired power generation performance.

[0055] Furthermore, the conductive porous member 30A may have a porosity of 10% or more and 40% or less. This makes it possible to create a conductive porous member 30A with gas permeability suitable for the intermediate layer 30 of cell 1, for example.

[0056] Furthermore, the conductive porous member 30A may further contain second metal particles 34. The second metal particles 34 are metal particles 31 having a particle diameter of 1 μm or more.

[0057] Furthermore, the conductive porous member 30A may have a skeletal structure in which a plurality of particles, including titanium oxide particles 32 and second metal particles 34, are linked together. This allows, for example, adjustment of the mixing ratio of second metal particles 34, which have a large linear thermal expansion coefficient, and titanium oxide particles 32, which have a small linear thermal expansion coefficient. Therefore, the linear thermal expansion coefficient of the conductive porous member 30A as a whole can be adjusted. In addition, by incorporating the second metal particles 34, which are highly conductive metals, into the skeletal structure, the conductivity of the entire conductive porous member 30A is improved. Note that "skeletal structure including titanium oxide particles 32 and second metal particles 34" refers to a structure in which the framework, which is the skeleton that supports the shape, contains both titanium oxide particles 32 and second metal particles 34. The skeletal structure may have, for example, a three-dimensional network structure or a lattice structure. The titanium oxide particles 32 and second metal particles 34 constituting the skeleton may be bonded to each other, or to each other, or to titanium oxide particles 32 and second metal particles 34. The skeletal structure can be described as a structure in which multiple particles, including titanium oxide particles 32 and second metal particles 34, are connected. The first metal particles 33 are not included in the multiple particles that constitute the skeletal structure and are not incorporated into the skeletal structure. Even if the first metal particles 33 are removed from the conductive porous member 30A, the mesh-like, lattice-like framework is maintained. The first metal particles 33 may be in contact with only one titanium oxide particle 32 and not in contact with the other titanium oxide particles 32 and the second metal particles 34.

[0058] Furthermore, the conductive porous member 30A may have a skeletal structure of titanium oxide particles 32. Generally, metals are easily oxidized and reduced, and relatively large volume changes tend to occur as a result of oxidation and reduction. Titanium oxide particles 32 are relatively stable and resistant to oxidation and reduction, and relatively resistant to volume changes. By having a skeletal structure of titanium oxide particles 32 that is resistant to volume changes, for example, the overall volume change of the conductive porous member 30A caused by oxidation and reduction can be reduced. Note that "skeletal structure of titanium oxide particles 32" means that the framework that supports the shape contains only titanium oxide particles 32. In other words, if a mesh-like, lattice-like framework is maintained even when elements other than titanium oxide particles 32, namely the first metal particles 33 and the second metal particles 34, are removed from the conductive porous member 30A, then the conductive porous member 30A has a skeletal structure of titanium oxide particles 32.

[0059] The metal particles 31 may be, for example, metallic Ni. The conductive porous member 30A may also contain metal particles 31 other than the first metal particles 33 and the second metal particles 34.

[0060] The conductive porous member 30A may contain oxide particles other than titanium oxide particles 32. Such oxide particles may be, for example, rare earth element oxides (Y ２ O ３ , CEO ２ etc.), transition metal oxides (Fe ２ O ３ ZrO in solid solution of rare earth element oxides (such as CuO, etc.) ２ They are equivalent.

[0061] Here, whether the titanium oxide particles 32 in the intermediate layer 30 of cell 1 are first titanium oxide particles 35 with a first portion 37 located on the surface portion 35a can be confirmed, for example, by observing and analyzing the cross-section of the intermediate layer 30 using a STEM (scanning transmission electron microscope). Specifically, a portion of cell 1 including the intermediate layer 30, which is a conductive porous material, is cut out to prepare a resin-embedded sample. The resin-embedded sample is processed using a focused ion beam (FIB) to prepare a thin film sample with a thickness of several μm having the cross-section of the intermediate layer 30. The thin film sample is observed using a STEM, and the titanium oxide particles 32 contained in the intermediate layer 30 are identified by elemental analysis such as energy-dispersive X-ray spectroscopy (EDS). The surface portion 35a of the identified titanium oxide particles 32 is analyzed by line analysis or surface analysis using electron energy loss spectroscopy (EELS) to obtain an energy loss profile of the analyzed area. From the obtained energy loss profile, it is determined that TiO is present in the analyzed area. ２ KaTiO ｘ Determine whether it is TiO ｘ The area where the substance is detected is designated as the first area 37, and the titanium oxide particle 32 having the first area 37 on its surface layer 35a is designated as the first titanium oxide particle 35.

[0062] The occupancy ratio of the first portion 37 in the first titanium oxide particle 35 is obtained by surface analysis of the cross-section of the first titanium oxide particle 35 using EELS. The total area of ​​the surface analysis of the cross-section of the first titanium oxide particle 35 is divided into TiO ｘ The ratio of the area in which it was detected should be calculated and used as the occupancy ratio of the first part 37.

[0063] Whether a metal particle 31 is a first metal particle 33 or a second metal particle 34 can be confirmed, for example, by processing an SEM (Scanning Electron Microscope) image taken of a cross-section of the intermediate layer 30. Specifically, a cross-section of the intermediate layer 30 of cell 1 is photographed, and the metal particles 31 located in the intermediate layer 30 of the obtained SEM image are identified. Then, the equivalent circle diameter is calculated from the contour of each particle obtained by image processing. Using the calculated equivalent circle diameter, it is determined whether a metal particle 31 is a first metal particle 33 or a second metal particle 34. Furthermore, the proportion of the first metal particle 33 in the metal particle 31 can be determined, for example, by observing the cross-section of the intermediate layer 30 at five arbitrary locations in cell 1 with an SEM and taking an SEM image at a magnification of 20,000x. Each SEM image is processed as described above, and the total area S0 of the metal particles 31 and the total area S1 of the first metal particles 33 included in each SEM image are calculated. The proportion of the first metal particle 33 in the total metal particle 31 can be determined by the average value of S1 / S0 for each SEM image.

[0064] The porosity of the intermediate layer 30 can be determined, for example, by image processing of an SEM image taken of a cross-section of the intermediate layer 30. Specifically, the voids 36 (see Figure 2A) can be identified from the cross-sectional SEM image, and the area ratio of the voids 36 can be calculated by image analysis to obtain the porosity of the intermediate layer 30. The porosity of the intermediate layer 30 can also be obtained by averaging the results calculated from SEM images of three arbitrary cross-sections.

[0065] Furthermore, the conductive porous member 30A can be manufactured, for example, as follows: A slurry is prepared by mixing oxide powder, which is the raw material, with two types of metal powders with different average particle sizes, and adding additives such as solvents, organic binders, and pore-forming materials as needed. The two types of metal powders with different average particle sizes are, for example, metal powder A having an average particle size of 0.5 times or more the average particle size of the oxide powder, and metal powder B having an average particle size of 0.3 times or less the average particle size of the oxide powder. A molded body is produced using the prepared slurry by a well-known molding method, such as sheet molding. A porous sintered body is obtained by firing the produced molded body at a predetermined temperature in an oxidizing atmosphere. By heat-treating the porous sintered body in a reducing atmosphere, the metal particles oxidized by firing in an oxidizing atmosphere are reduced, and the conductive porous member 30A is obtained. Note that instead of two types of metal powders with different particle sizes, two types of metal oxide powders with different particle sizes may be used as raw materials. Even in this case, by heat-treating the porous sintered body obtained by firing in an oxidizing atmosphere in a reducing atmosphere, the metal oxide particles in the porous sintered body are reduced, and a conductive porous member 30A is obtained.

[0066] Furthermore, the intermediate layer 30 of cell 1 can be manufactured, for example, as follows: Using the slurry described above, a coating ink is prepared as needed. The coating ink is applied to the metal plate 23. On the coated molded body, a precursor of the element part 3 (fuel electrode precursor, solid electrolyte layer precursor, air electrode precursor, etc.) is formed as needed, and then fired at a predetermined temperature in an oxidizing atmosphere. By further heat-treating it in a reducing atmosphere, a cell 1 having an intermediate layer 30 of conductive porous member 30A can be obtained.

[0067] The above-described method for manufacturing the conductive porous member 30A and the intermediate layer 30 is merely illustrative, and they may be manufactured by any method. Although the intermediate layer 30 was described as an example of the conductive porous member 30A, the conductive porous member 30A may be, for example, a gas diffusion layer. The conductive porous member 30A may also be a porous cermet support having one or more gas channels inside. A porous cermet support can be manufactured, for example, as follows: An oxide powder and two types of metal powders with different average particle sizes are mixed with additives such as a solvent, organic binder, and pore-forming material as needed, and a tubular molded body having one or more cavities inside is manufactured by extrusion molding or the like. A porous sintered body is obtained by firing the manufactured molded body at a predetermined temperature in an oxidizing atmosphere. A precursor of the element part 3 (fuel electrode precursor, solid electrolyte layer precursor, air electrode precursor, etc.) is formed on the manufactured molded body or porous sintered body as needed, and then fired at a predetermined temperature in an oxidizing atmosphere. By introducing a reducing gas into the cavity of the porous sintered body on which the element portion 3 is formed and performing heat treatment, the metal oxide particles in the porous sintered body are reduced, and a cell 1 equipped with a porous cermet support can be obtained.

[0068] <Configuration of the Electrochemical Cell Apparatus> 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 embodiment. Figure 3B is a cross-sectional view taken along the line X-X shown in Figure 3A. Figure 3C is a top view showing an example of the electrochemical cell apparatus according to the embodiment.

[0069] 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 (Y-axis direction shown in Figure 1A) of the element section 3, and a fixing member 12.

[0070] 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 metal and are electrically conductive.

[0071] 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.

[0072] The gas tank 16 has an opening that supplies reaction gas to a plurality of 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.

[0073] In the example shown in Figure 3A, fuel gas is stored in an 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 internal flow path 24 (see Figure 1B) of the cell 1. The fuel gas supplied to the gas tank 16 is generated in a reformer 102 (see Figure 4), which will be described later.

[0074] 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.

[0075] As shown in Figure 3A, the cell stack device 10 may comprise 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 upper surface. Each support member 15 is positioned 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 comprise only one cell stack 11, or it may comprise three or more cell stacks 11.

[0076] The shape of the insertion hole 15a may be, for example, an oval shape when viewed from above. The oval shape includes an elliptical shape and a rectangular shape with rounded corners. The length of the insertion hole 15a may be, for example, greater than the distance between the two end current collectors 17 located at both ends of the cell stack 11, in the direction of arrangement of the cell 1, i.e., the thickness direction (Y-axis direction shown in Figure 1A). The width of the insertion hole 15a may be, for example, greater than the length of the cell 1 in the width direction (X-axis direction shown in Figure 1A).

[0077] 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. As a result, the inner wall of the insertion hole 15a is joined and fixed to the lower ends of the multiple cells 1, and the lower ends of the cells 1 are also joined and fixed 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.

[0078] 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.

[0079] Examples of crystallized glass include SiO ２ -CaO system, MgO-B ２ O ３ System, La ２ O ３ -B ２ O ３ - MgO system, La ２ O ３ -B ２ O ３ - ZnO system, SiO ２ Any of the following materials may be used, particularly SiO ２ -MgO-based materials may also be used.

[0080] Furthermore, as shown in Figure 3B, a conductive member 18 may be interposed between adjacent cells 1 among the multiple cells 1. The conductive member 18 electrically connects one adjacent cell 1 and the other cell 1 in series. More specifically, the conductive member 18 connects the fuel electrode 5 of one cell 1 and the air electrode 8 of the other cell 1. The conductive member 18 may be integrated with the current collector 27 shown in Figure 1B. The current collector 27 may also serve as the conductive member 18. The conductive member 18 may be a separate member from the current collector 27. The conductive member 18 may be fixed to the air electrode 8 of the other cell 1 via a conductive adhesive and electrically joined.

[0081] 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 portion 19 that protrudes to the outside of the cell stack 11. The conductive portion 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.

[0082] 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 may have a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0083] 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.

[0084] 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.

[0085] Although not shown in Figures 3A to 3C, the cell stack device 10 may also include a second gas tank at the top of the cell stack 11, which fixes the upper ends of multiple cells 1 and recovers the gas discharged from the flow path 24 (see Figure 1B) inside the cells 1.

[0086] <Module> Next, a module according to the embodiment of this disclosure using the cell stack device 10 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 embodiment. Figure 4 shows the 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 housed inside has been taken out to the rear.

[0087] As shown in Figure 4, the module 100 comprises a cell stacking device 10 and a storage container 101 that houses the cell stacking device 10. A reformer 102 may also be positioned above the cell stacking device 10.

[0088] 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.

[0089] The fuel gas generated in the reformer 102 is then supplied to the flow path 24 of the cell 1 (see Figure 1B) through the gas flow pipe 20, the gas tank 16, and the support member 14.

[0090] If the cell stack device 10 is equipped with a second gas tank on top of the cell stack 11, the reformer 102 may be located in a place other than above the cell stack device 10. The raw fuel supply pipe 103, gas flow pipe 20, etc., may be appropriately arranged according to the arrangement of the cell stack device 10 and the reformer 102.

[0091] 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 power generation by cell 1, etc.

[0092] In such a module 100, as described above, the module 100 can be configured to house a cell stack device 10 that improves power generation performance, thereby improving power generation performance.

[0093] <Module Housing Device> Figure 5 is a schematic exploded perspective view showing an example of a module housing device according to this 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.

[0094] 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 modules 100. 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 modules 100. Note that in Figure 5, the auxiliary equipment housed in the auxiliary equipment housing chamber 116 is omitted from the illustration.

[0095] 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 air from inside the module storage room 115.

[0096] In such a module housing device 110, as described above, by providing the module housing chamber 115 with a module 100 that has improved power generation performance, the module housing device 110 can be made to have improved power generation performance.

[0097] [Other Embodiments] In the embodiments described above, a fuel cell cell, fuel cell stack device, fuel cell module, and fuel cell device were shown as examples of "electrochemical cell," "electrochemical cell device," "module," and "module housing device." Other examples include an electrolytic cell, electrolytic cell stack device, electrolytic module, and electrolytic device, respectively. The electrolytic cell has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen, or carbon dioxide into carbon monoxide and oxygen, by supplying electricity. In the embodiments described above, an oxide ion conductor or a hydrogen ion conductor was shown as an example of the electrolyte material for the electrochemical cell, but a hydroxide ion conductor may also be used. Such electrolytic cells, electrolytic cell stack devices, electrolytic modules, and electrolytic devices can improve electrolysis performance. Solid oxide type fuel cell cells and electrolytic cells are collectively referred to as solid oxide type electrochemical cells.

[0098] 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.

[0099] In one embodiment, (1) the conductive porous member comprises metal particles and titanium oxide particles, wherein the titanium oxide particles have TiO in the surface layer at a distance of 30 nm or less from the particle surface. ｘ It contains a first titanium oxide particle in which a first region having (0.5 ≤ x ≤ 1.95) is located.

[0100] (2) In the conductive porous member described in (1) above, the occupancy ratio of the first portion in the first titanium oxide particles may be 1% or more and 20% or less.

[0101] (3) In the conductive porous member of (1) or (2) above, the metal particles include first metal particles having a particle diameter of 0.5 μm or less, and the first metal particles may be in contact with the first titanium oxide particles.

[0102] (4) The conductive porous member described in (3) above may contain 10% to 40% of the first metal particles relative to the total amount of metal particles.

[0103] (5) In any one of the conductive porous members described in (1) to (4) above, the porosity may be 10% or more and 40% or less.

[0104] (6) In any one of the conductive porous members described in (1) to (5) above, the metal particles may include second metal particles having a particle diameter of 1 μm or more, and may have a skeletal structure in which a plurality of particles including the titanium oxide particles and the second metal particles are linked together.

[0105] (7) Any one of the conductive porous members described in (1) to (5) above may have a skeletal structure in which multiple titanium oxide particles are linked together.

[0106] In one embodiment, (8) the electrochemical cell comprises a metal plate, an element portion, and an intermediate layer located between the metal plate and the element portion, wherein the intermediate layer is one of the conductive porous members described in (1) to (7) above.

[0107] In one embodiment, (9) the electrochemical cell apparatus has a cell stack comprising the electrochemical cell described in (8) above.

[0108] In one embodiment, module (10) comprises the electrochemical cell device described in (9) above and a storage container housing the electrochemical cell device.

[0109] In one embodiment, the module housing device (11) comprises the module (10) described above, an auxiliary device configured to operate the module, and an outer case housing the module and the auxiliary device.

[0110] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. 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.

[0111] 1 Cell 3 Element section 5 Fuel electrode 6 Solid electrolyte layer 8 Air electrode 9 Sealing material 10 Cell stack device 23 Metal plate 30 Intermediate layer 30A Conductive porous member 31 Metal particles 32 Titanium oxide particles 33 First metal particles 34 Second metal particles 35 First titanium oxide particles 35a Surface layer 37 First section 100 Module 110 Module housing device

Claims

1. Containing metal particles and titanium oxide particles, the titanium oxide particles have TiO in the surface layer at a distance of 30 nm or less from the particle surface. ｘ A conductive porous member containing first titanium oxide particles in which a first region having (0.5 ≤ x ≤ 1.95) is located.

2. The conductive porous member according to claim 1, wherein the occupancy ratio of the first portion in the first titanium oxide particles is 1% or more and 20% or less.

3. The conductive porous member according to claim 1 or 2, wherein the metal particles include first metal particles having a particle diameter of 0.5 μm or less, and the first metal particles are in contact with the first titanium oxide particles.

4. The conductive porous member according to claim 3, comprising 10% or more and 40% or less of the first metal particles relative to the total amount of metal particles.

5. A conductive porous member according to any one of claims 1 to 4, wherein the porosity is 10% or more and 40% or less.

6. The conductive porous member according to any one of claims 1 to 5, wherein the metal particles include second metal particles having a particle diameter of 1 μm or more, and the plurality of particles including the titanium oxide particles and the second metal particles are linked together to form a skeletal structure.

7. A conductive porous member according to any one of claims 1 to 5, having a skeletal structure in which a plurality of titanium oxide particles are linked together.

8. An electrochemical cell comprising a metal plate, an element portion, and an intermediate layer located between the metal plate and the element portion, wherein the intermediate layer is a conductive porous member according to any one of claims 1 to 7.

9. An electrochemical cell apparatus having a cell stack comprising the electrochemical cell described in claim 8.

10. A module comprising an electrochemical cell apparatus as described in claim 9, and a storage container housing the electrochemical cell apparatus.

11. A module housing device comprising: a module according to claim 10; an auxiliary device configured to operate the module; and an outer case housing the module and the auxiliary device.

Images