Conductive member, electrochemical cell, electrochemical cell device, module, and module housing device

Abstract

This electroconductive member comprises a substrate and a polycrystal film. The substrate contains chromium. The polycrystal film contains a plurality of chromic oxide particles, and is disposed on the substrate. The polycrystal film contains a first element. The first element is disposed between chromic oxide particles, and has a smaller first ionization energy and a smaller free energy of oxide formation per mol of oxygen than chromium.

Description

[Technical Field]

[0001] The present disclosure relates to an electrically conductive member, an electrochemical cell, an electrochemical cell device, a module, and a module housing device. [Background technology]

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

[0003] [Patent Document 1] International Publication No. 2009 / 131180 Summary of the Invention

[0004] A conductive member according to one aspect of the present invention includes a substrate and a polycrystalline film. The substrate contains chromium. The polycrystalline film includes a plurality of chromium oxide particles and is located on the substrate. The polycrystalline film includes a first element. The first element is located between the chromium oxide particles and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium.

[0005] The electrochemical cell of the present disclosure includes an element portion and the conductive member described above. The conductive member is connected to the element portion.

[0006] The electrochemical cell device of the present disclosure also includes a cell stack including the electrochemical cell described above.

[0007] The module of the present disclosure includes the electrochemical cell device described above and a container that houses the electrochemical cell device.

[0008] The module housing device of the present disclosure includes the module described above, an auxiliary device for operating the module, and an exterior case for housing the module and the auxiliary device. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1A is a cross-sectional view showing an example of an electrochemical cell according to a first embodiment. [Figure 1B] FIG. 1B is a side view of an example of the electrochemical cell according to the first embodiment, viewed from the air electrode side. [Figure 1C] FIG. 1C is a side view of an example of an electrochemical cell according to the first embodiment, viewed from the interconnector side. [Figure 2A] FIG. 2A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. [Figure 2B] FIG. 2B is a cross-sectional view taken along line XX shown in FIG. 2A. [Figure 2C] FIG. 2C is a top view showing an example of the electrochemical cell device according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing an example of a conductive member according to an embodiment. [Figure 4A] FIG. 4A is a cross-sectional view taken along the line AA shown in FIG. [Figure 4B] FIG. 4B is an enlarged view of region B shown in FIG. 4A. [Figure 4C] FIG. 4C is an enlarged view of the polycrystalline film shown in FIG. 4B. [Figure 5] FIG. 5 is an external perspective view showing an example of the module according to the first embodiment. [Figure 6] FIG. 6 is an exploded perspective view schematically illustrating an example of a module housing device according to the first embodiment. [Figure 7A] FIG. 7A is a cross-sectional view showing an electrochemical cell according to a second embodiment. [Figure 7B] FIG. 7B is an enlarged cross-sectional view of the conductive member according to the second embodiment. [Figure 8A]FIG. 8A is a perspective view showing an electrochemical cell according to a third embodiment. [Figure 8B] FIG. 8B is a partial cross-sectional view of the electrochemical cell shown in FIG. 8A. [Figure 8C] FIG. 8C is a partial cross-sectional view of the electrochemical cell shown in FIG. 8A. [Figure 9A] FIG. 9A is a cross-sectional view showing an example of an electrochemical cell according to a fourth embodiment. [Figure 9B] FIG. 9B is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 9C] FIG. 9C is a cross-sectional view showing another example of the electrochemical cell according to the fourth embodiment. [Figure 9D] FIG. 9D is an enlarged cross-sectional view of region C shown in FIG. 9A. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the conductive 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 the disclosure is not limited to the embodiments described below.

[0011] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0012] [First embodiment] <Electrochemical cell configuration> First, with reference to Figures 1A to 1C, an electrochemical cell according to a first embodiment will be described using an example of a solid oxide fuel cell. The electrochemical cell device may include a cell stack having a plurality of electrochemical cells. An electrochemical cell device having a plurality of electrochemical cells will be simply referred to as a cell stack device.

[0013] Fig. 1A is a cross-sectional view showing an example of an electrochemical cell according to the first embodiment, Fig. 1B is a side view of the example of the electrochemical cell according to the first embodiment as seen from the air electrode side, and Fig. 1C is a side view of the example of the electrochemical cell according to the first embodiment as seen from the interconnector side. Note that Figs. 1A to 1C show enlarged views of parts of each component of the electrochemical cell. Hereinafter, the electrochemical cell may also be simply referred to as a cell.

[0014] 1A to 1C, cell 1 is a hollow, flat, elongated plate. As shown in Fig. 1B, the shape of the entire cell 1 as viewed from the side is, for example, a rectangle with a side length in the length direction L of 5 cm to 50 cm and a length in the width direction W perpendicular to the length direction L of 1 cm to 10 cm. The thickness of the entire cell 1 in the thickness direction T is, for example, 1 mm to 5 mm.

[0015] 1A, the cell 1 includes a conductive support substrate 2, an element section 3, and an interconnector 4. The support substrate 2 is columnar, having a pair of opposing first and second surfaces n1 and n2, and a pair of arc-shaped side surfaces m connecting the first and second surfaces n1 and n2.

[0016] The element section 3 is located on a first surface n1 of the support substrate 2. The element section 3 has an anode 5, a solid electrolyte layer 6, and an cathode 8. In the example shown in FIG. 1A, an interconnector 4 is located on a second surface n2 of the cell 1. The cell 1 may also include an intermediate layer 7 between the solid electrolyte layer 6 and the cathode 8.

[0017] 1B, the air electrode 8 does not extend to the lower end of the cell 1. At the lower end of the cell 1, only the solid electrolyte layer 6 is exposed on the surface of the first face n1. As shown in FIG. 1C, the interconnector 4 may extend to the lower end of the cell 1. At the lower end of the cell 1, the interconnector 4 and the solid electrolyte layer 6 are exposed on the surface. As shown in FIG. 1A, the solid electrolyte layer 6 is exposed on the surface of a pair of arc-shaped side faces m of the cell 1. The interconnector 4 does not have to extend to the lower end of the cell 1.

[0018] Each of the components that make up the cell 1 will be described below.

[0019] The support substrate 2 has gas flow channels 2a therein through which gas flows. The example of the support substrate 2 shown in FIG. 1A has six gas flow channels 2a. The support substrate 2 is gas permeable, and allows the gas flowing in the gas flow channels 2a to pass through to the anode 5. The support substrate 2 may be conductive. The conductive support substrate 2 collects electricity generated in the element section 3 to the interconnector 4.

[0020] The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. The iron group metal component may be, for example, Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0021] The material of the anode 5 may be any known material. The anode 5 may be a porous conductive ceramic containing an electronically conductive material and an ionically conductive material. Examples of the conductive ceramic include ceramics containing calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides, and Ni and / or NiO. The rare earth element oxide may contain a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides is sometimes referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia.

[0022] The solid electrolyte layer 6 is an electrolyte and transfers ions between the fuel electrode 5 and the air electrode 8. At the same time, the solid electrolyte layer 6 has gas barrier properties and makes it difficult for leakage of fuel gas and oxygen-containing gas to occur.

[0023] The material of the solid electrolyte layer 6 may be, for example, ZrO2 with 3 mol % to 15 mol % of a rare earth element oxide dissolved therein. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may include, for example, ZrO2 with Yb, Sc, or Gd dissolved therein, CeO2 with La, Nd, or Yb dissolved therein, BaZrO3 with Sc or Yb dissolved therein, or BaCeO3 with Sc or Yb dissolved therein.

[0024] The air electrode 8 is gas permeable. The open porosity of the air electrode 8 may be, for example, in the range of 20% to 50%, and particularly 30% to 50%. The open porosity of the air electrode 8 may also be referred to as the void ratio of the air electrode 8.

[0025] There are no particular restrictions on the material of the air electrode 8 as long as it is one that is generally used for air electrodes. The material of the air electrode 8 may be, for example, a conductive ceramic such as a so-called ABO3 type perovskite oxide.

[0026] 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 O3, La x Sr 1-x MnO3, La x Sr 1-x FeO3, La x Sr 1-x CoO3, etc. Note that x is 0 <x<1、yは0<y<1である。

[0027] Furthermore, when the element section 3 has an intermediate layer 7, the intermediate layer 7 functions as a diffusion suppression layer. When Sr (strontium) contained in the air electrode 8 diffuses into the solid electrolyte layer 6, a resistive layer of SrZrO3 is formed in the solid electrolyte layer 6. The intermediate layer 7 makes it difficult for Sr to diffuse, thereby making it difficult for SrZrO3 to be formed.

[0028] There are no particular restrictions on the material of intermediate layer 7, as long as it is generally used as an element diffusion prevention layer between air electrode 8 and solid electrolyte layer 6. The material of intermediate layer 7 may include, for example, cerium oxide (CeO2) in which a rare earth element other than Ce (cerium) is dissolved. Examples of such rare earth elements that may be used include Gd (gadolinium) and Sm (samarium).

[0029] Furthermore, the interconnector 4 is dense and makes it difficult for leakage of the fuel gas flowing through the gas flow channel 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2 to occur. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0030] Lanthanum chromite-based perovskite oxides (LaCrO3-based oxides), lanthanum strontium titanium-based perovskite oxides (LaSrTiO3-based oxides), etc. may be used as the material for the interconnector 4. These materials are conductive and are resistant to reduction and oxidation even when in contact with fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air.

[0031] <Configuration of electrochemical cell device> Next, an electrochemical cell device according to this embodiment using the above-described cell 1 will be described with reference to Figures 2A to 2C. Figure 2A is a perspective view showing an example of the electrochemical cell device according to the first embodiment, Figure 2B is a cross-sectional view taken along line XX shown in Figure 2A, and Figure 2C is a top view showing an example of the electrochemical cell device according to the first embodiment.

[0032] As shown in FIG. 2A, the cell stack device 10 includes a cell stack 11 having a plurality of cells 1 arranged (stacked) in a thickness direction T of the cells 1 (see FIG. 1A), and a fixing member 12.

[0033] The fixing member 12 has a fixing material 13 and a support member 14. The support member 14 supports the cell 1. The fixing material 13 fixes the cell 1 to the support member 14. The support member 14 also has a support 15 and a gas tank 16. The support 15 and gas tank 16, which are the support member 14, are made of metal and are electrically conductive.

[0034] 2B, the support body 15 has insertion holes 15a into which the lower ends of the plurality of cells 1 are inserted. The lower ends of the plurality of cells 1 and the inner wall of the insertion holes 15a are joined with a fixing material 13.

[0035] The gas tank 16 has an opening for supplying a reaction gas to the cells 1 through the insertion holes 15a, and a recessed groove 16a located around the opening. The outer peripheral edge of the support 15 is joined to the gas tank 16 by a bonding material 21 filled in the recessed groove 16a of the gas tank 16.

[0036] In the example shown in Fig. 2A, fuel gas is stored in an internal space 22 formed by a support 15, which is the support member 14, and a gas tank 16. A gas circulation pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas circulation pipe 20, and is supplied from the gas tank 16 to a gas flow path 2a (see Fig. 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated in a reformer 102 (see Fig. 5), which will be described later.

[0037] The hydrogen-rich fuel gas can be produced by steam reforming the raw fuel, etc. When the fuel gas is produced by steam reforming, the fuel gas contains water vapor.

[0038] The example shown in FIG. 2A includes two rows of cell stacks 11, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 has a plurality of cells 1. Each cell stack 11 is fixed to a corresponding support 15. The gas tank 16 has two through-holes on its top surface. A support 15 is disposed in each through-hole. An internal space 22 is formed by the one gas tank 16 and the two supports 15.

[0039] The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. For example, the length of the insertion hole 15a in the arrangement direction of the cells 1, i.e., the thickness direction T, may be greater than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. For example, the width of the insertion hole 15a may be greater than the length of the cell 1 in the width direction W (see FIG. 1A).

[0040] 2B, a fixing material 13 is filled and solidified in the joints between the inner walls of the insertion holes 15a and the lower ends of the cells 1. This bonds and fixes the inner walls of the insertion holes 15a to the lower ends of the multiple cells 1, respectively, and also bonds and fixes the lower ends of the cells 1 to each other. The gas flow path 2a of each cell 1 communicates with the internal space 22 of the support member 14 at its lower end.

[0041] A material with low conductivity, such as glass, can be used for the fixing material 13 and the bonding material 21. Specific materials for the fixing material 13 and the bonding material 21 include amorphous glass, and in particular, crystallized glass.

[0042] As the crystallized glass, for example, any of materials such as SiO2-CaO, MgO-B2O3, La2O3-B2O3-MgO, La2O3-B2O3-ZnO, and SiO2-CaO-ZnO may be used, and in particular, SiO2-MgO materials may be used.

[0043] 2B, a conductive member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 electrically connects the anode 5 of one adjacent cell 1 to the cathode 8 of the other cell 1 in series. More specifically, the conductive member 18 connects the interconnector 4 electrically connected to the anode 5 of one adjacent cell 1 to the cathode 8 of the other cell 1. Details of the conductive member 18 connected to adjacent cells 1 will be described later.

[0044] 2B, an end current collecting member 17 is electrically connected to the cell 1 located at the outermost position in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive part 19 that protrudes to the outside of the cell stack 11. The conductive part 19 collects electricity generated by power generation in the cells 1 and extracts it to the outside. Note that the end current collecting member 17 is not shown in FIG. 2A.

[0045] 2C, the cell stack device 10 has two cell stacks 11A and 11B connected in series to function as a single battery. Therefore, the conductive part 19 of the cell stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0046] The positive electrode terminal 19A is a positive electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the positive electrode side end current collecting member 17 of the cell stack 11A. The negative electrode terminal 19B is a negative electrode when the power generated by the cell stack 11 is output to the outside, and is electrically connected to the negative electrode side end current collecting member 17 of the cell stack 11B.

[0047] The connection terminal 19C electrically connects the end current collecting member 17 on the negative electrode side of the cell stack 11A and the end current collecting member 17 on the positive electrode side of the cell stack 11B.

[0048] <Details of conductive materials> Next, details of the conductive member 18 according to the first embodiment will be described with reference to Fig. 3 to Fig. 4C. Fig. 3 is a cross-sectional view showing an example of the conductive member according to the embodiment.

[0049] As shown in Fig. 3, the conductive member 18 has a connection portion 18a connected to one adjacent cell 1 and a connection portion 18b connected to the other adjacent cell 1. The conductive member 18 also has linking portions 18c at both ends in the width direction W, which connect the connection portions 18a and 18b. This allows the conductive member 18 to electrically connect the cells 1 adjacent to each other in the thickness direction T. Note that Fig. 3 shows a simplified shape of the cell 1.

[0050] Furthermore, the connection portions 18a and 18b have a first surface 181 facing the cell 1 and a second surface 182 facing the connection portions 18b and 18a.

[0051] Fig. 4A is a cross-sectional view taken along line AA shown in Fig. 3. Fig. 4B is an enlarged view of region B shown in Fig. 4A.

[0052] The conductive member 18 extends in the longitudinal direction L of the cell 1. As shown in Fig. 4A, a plurality of connection portions 18a, 18b of the conductive member 18 are alternately positioned along the longitudinal direction L of the cell 1. The conductive member 18 is in contact with the cell 1 at each of the connection portions 18a, 18b.

[0053] 4B, conductive member 18 has a substrate 41, a polycrystalline film 42, and a coating layer 43. Conductive member 18 has a first surface 181 and a second surface 182 located at both ends in the thickness direction T of cell 1. Conductive member 18 also has third surfaces 183 and 184 connecting first surface 181 and second surface 182.

[0054] The conductive member 18 (connection portion 18b) is joined to the cell 1 via a joining material 50. The joining material 50 is located between the first surface 181 of the conductive member 18 and the cell 1, and joins the conductive member 18 to the cell 1. In addition, the second surface 182 and the third surfaces 183, 184 are exposed to an oxidizing atmosphere, such as air.

[0055] The substrate 41 has electrical conductivity and heat resistance. The substrate 41 contains chromium. The substrate 41 is, for example, stainless steel. The substrate 41 may contain, for example, a metal oxide.

[0056] Fig. 4C is an enlarged view of the polycrystalline film shown in Fig. 4B. Polycrystalline film 42 is located on substrate 41. As shown in Fig. 4C, polycrystalline film 42 includes a plurality of chromium oxide particles 421 and first particles 422.

[0057] The chromium oxide particles 421 contain, for example, chromium oxide (Cr2O3). When the base material 41 contains the chromium oxide particles 421 in this manner, the durability of the conductive member 18 is enhanced. The chromium oxide particles 421 may have, for example, an average particle size (circle-equivalent diameter) of 500 nm or less, particularly 100 nm to 350 nm. The chromium oxide particles 421 may also contain components other than chromium oxide. The chromium oxide particles 421 may not contain the first element. Details of the first element will be described later.

[0058] The first particles 422 are located between the chromium oxide particles 421. The first particles 422 contain a first element. The first element has a first ionization energy and a free energy of formation of its oxide per mole of oxygen that are smaller than those of chromium. Examples of the first element include Y, Ce, Eu, Gd, Pr, Yb, and Zr. The free energy of formation is also referred to as the Gibbs energy of formation. The free energy of formation can be found in a thermodynamic database, such as the "Nuclear Fuel and Nuclear Materials Thermodynamics Database." The first element may be any of Ce, Eu, Pr, and Zr. The first element may be located in the first particles 422 as an oxide of such an element. Examples of such oxides of the first element include Y2O3, CeO2, EuO, Gd2O3, PrO2, Yb2O3, and ZrO2.

[0059] The first particles 422 may contain, for example, one or more of the first element. The first particles 422 may also contain an element other than the first element. The first particles 422 may contain, for example, CeO2 solid-solubilized with Sm (samarium) or Gd (gadolinium), or may contain ZrO2 solid-solubilized with Sc (scandium), Y (yttrium), Yb (ytterbium), or the like, so-called stabilized zirconia or partially stabilized zirconia. The first particles 422 may also contain, for example, a composite oxide containing the first element, such as Ce2Ti2O7.

[0060] Polycrystalline film 42 may have, for example, a grain boundary phase containing the first element between chromium oxide particles 421. The grain boundary phase containing the first element may contain, for example, 0.1 atomic % or more of the first element.

[0061] The polycrystalline film 42 may have a flat interface with the substrate 41, or may have an uneven, wavy interface with the substrate 41, for example.

[0062] Furthermore, polycrystalline film 42 may contain, for example, Si. For example, when polycrystalline film 42 has irregularities at the interface with substrate 41, such Si may be located at the tips of the protrusions protruding toward substrate 41.

[0063] In this way, since the polycrystalline film 42 of the conductive member 18 contains the first element, Cr in the base material 41 is less likely to diffuse, and therefore the polycrystalline film 42 is less likely to grow. This makes it possible to reduce the deterioration of the power generation performance of the cell 1.

[0064] Furthermore, the thickness of the polycrystalline film 42 may be, for example, 20 nm to 5 μm, or even 200 nm to 1.5 μm. When the polycrystalline film 42 has such a thickness, for example, the effect of the polycrystalline film 42 on the internal resistance is reduced, and the internal resistance of the conductive member 18 is therefore less likely to increase. This makes it possible to reduce a decrease in the power generation performance of the cell 1.

[0065] The conductive member 18 may have an oxide of the first element located on the polycrystalline film 42. The oxide of the first element may be, for example, Y2O3, CeO2, EuO, Gd2O3, PrO2, Yb2O3, or ZrO2.

[0066] The presence or absence of the first element and the size of the first particles 422 containing the first element can be confirmed by, for example, mapping the first element using an HAADF-STEM (high-angle annular dark-field scanning transmission electron microscope), a FIB-SEM (focused ion beam scanning electron microscope), or an EPMA (electron probe microanalyzer) on a cross section of the conductive member 18. The average thickness of the polycrystalline film 42 can be obtained by, for example, using an HAADF-STEM with an acceleration voltage of 200 kV to map chromium and the first element at a magnification of 1,000,000 times on a cross section of the conductive member 18, measuring the thicknesses of 10 or more points where chromium and the first element are detected, and calculating the average value.

[0067] Such a conductive member 18 can be obtained by forming a coating containing the first element on the surface of a chromium-containing substrate 41, and then heat-treating the coating containing the first element and the substrate 41. The coating containing the first element may be, for example, an oxide coating of the first element. The coating containing the first element may be formed by, for example, a physical vapor deposition method such as IAD (Ion Assisted Deposition) or by applying a slurry containing an oxide of the first element. The thickness of the coating containing the first element may be, for example, 1 nm to 1000 nm. The thickness of the coating containing the first element may be, for example, 5 nm to 150 nm, or even 10 nm to 100 nm. The coating containing the first element may contain oxide particles of the first element having a diameter of, for example, 30 nm or less. The coating containing the first element may contain, for example, acicular or dendritic oxide particles of the first element. The acicular or dendritic oxide particles of the first element may have a minor axis of 30 nm or less. Oxide particles of the first element having such a diameter or minor axis are likely to be arranged between particles of the polycrystalline film 42 by heat treatment. The heat treatment of the coating containing the first element and the substrate 41 may be carried out, for example, in air at a temperature of 50°C to 1100°C. The substrate 41 does not necessarily need to contain the first element.

[0068] The coating layer 43 is located on the polycrystalline film 42. The coating layer 43 coats the polycrystalline film 42 over the entire thickness direction T and length direction L of the cell 1. The coating layer 43 contains an element different from that of the polycrystalline film 42. The coating layer 43 is, for example, conductive. By being located between the polycrystalline film 42 and the oxidizing atmosphere, the coating layer 43 can, for example, suppress the release of chromium contained in the substrate 41 and / or the polycrystalline film 42. This improves the durability of the conductive member 18, thereby improving the durability of the cell 1.

[0069] Furthermore, the coating layer 43 may contain, for example, an oxide containing Mn (manganese) and Co (cobalt). The coating layer 43 may be porous. The coating layer 43 may have a layered structure containing different elements.

[0070] <module> Next, a module according to an embodiment of the present disclosure using the electrochemical cell device described above will be described with reference to Fig. 5. Fig. 5 is an external perspective view showing the module according to the first embodiment. Fig. 5 shows a state in which the front and rear surfaces, which are part of the storage container 101, have been removed and the cell stack device 10 of the fuel cell stored inside has been pulled out to the rear.

[0071] 5, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container 101. A reformer 102 is disposed above the cell stack device 10.

[0072] The reformer 102 reforms raw fuel such as natural gas or kerosene to generate fuel gas, which is then supplied to the cell 1. The raw fuel is supplied to the reformer 102 through a raw fuel supply pipe 103. The reformer 102 may also include a vaporizer 102a that vaporizes water, and a reformer 102b. The reformer 102b includes a reforming catalyst (not shown) and reforms the raw fuel into fuel gas. Such a reformer 102 can perform steam reforming, a highly efficient reforming reaction.

[0073] The fuel gas produced in the reformer 102 is supplied to the gas flow channel 2a of the cell 1 (see FIG. 1A) through the gas distribution pipe 20, the gas tank 16, and the support member 14.

[0074] Furthermore, in the module 100 having the above-described configuration, the temperature inside the module 100 during normal power generation becomes approximately 500°C to 1000°C due to the combustion of gas and the power generation of the cells 1.

[0075] As described above, such a module 100 is configured to house a cell stack device 10 having multiple cells 1 whose internal resistance is less likely to increase, thereby making it possible to create a module 100 that reduces the decline in power generation performance.

[0076] <Module storage device> Fig. 6 is an exploded perspective view showing an example of a module housing device according to the first embodiment. The module housing device 110 according to this embodiment includes an outer case 111, the module 100 shown in Fig. 5, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed in the outer case 111. Note that some components are omitted in Fig. 6.

[0077] An exterior case 111 of a module accommodating device 110 shown in Fig. 6 has support columns 112 and an exterior plate 113. A partition plate 114 divides the interior of the exterior case 111 into upper and lower sections. The space above the partition plate 114 in the exterior case 111 is a module accommodating chamber 115 that accommodates the module 100, and the space below the partition plate 114 in the exterior case 111 is an accessory accommodating chamber 116 that accommodates accessory equipment for operating the module 100. Note that in Fig. 6, the accessory equipment accommodated in the accessory accommodating chamber 116 is omitted.

[0078] The partition plate 114 also has an air flow port 117 for allowing air from the auxiliary equipment housing chamber 116 to flow toward the module housing chamber 115. The exterior plate 113 that constitutes the module housing chamber 115 has an exhaust port 118 for exhausting air from within the module housing chamber 115.

[0079] In such a module accommodating device 110, as described above, by providing the module 100 that reduces the degradation of power generation performance in the module accommodating chamber 115, the module accommodating device 110 can be made to reduce the degradation of power generation performance.

[0080] In the above embodiment, a case where a hollow flat plate-type support substrate is used is exemplified, but the present invention can also be applied to a cell stack device that uses a cylindrical support substrate.

[0081] [Second embodiment] Next, an electrochemical cell and an electrochemical cell device according to a second embodiment will be described with reference to FIGS. 7A and 7B.

[0082] In the above-described embodiment, a so-called "vertical stripe type" electrochemical cell device has been exemplified, in which only one element unit including a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the surface of a support substrate. However, the present invention can also be applied to a horizontal stripe type electrochemical cell device in which so-called "horizontal stripe type" electrochemical cells are arranged, in which element units are provided at multiple locations spaced apart from each other on the surface of a support substrate, and adjacent element units are electrically connected.

[0083] FIG. 7A is a cross-sectional view showing an electrochemical cell according to a second embodiment. In a cell stack device 10A, multiple cells 1A extend in a longitudinal direction L from a pipe 73 through which a fuel gas flows. Each cell 1A has multiple element units 3A on a support substrate 2. A gas flow path 2a through which gas flows from the pipe 73 is provided inside the support substrate 2. The element units 3A on the support substrate 2 are electrically connected by a connecting layer (not shown). The multiple cells 1A are electrically connected to each other via conductive members 18. The conductive members 18 are located between the element units 3A of each cell 1A and electrically connect adjacent cells 1A. Specifically, the conductive members 18 electrically connect the current collector or interconnector electrically connected to the air electrode of the element unit 3A of one of the adjacent cells 1A to the current collector or interconnector electrically connected to the anode of the element unit 3A of the other cell 1A.

[0084] 7B is an enlarged cross-sectional view of a conductive member according to the second embodiment. As shown in FIG. 7B, conductive member 18 is bonded to adjacent cells 1A via bonding material 50. Conductive member 18 has first surface 181 and second surface 182 that face each other with base material 41 interposed therebetween. Conductive member 18 also has third surfaces 183 and 184 that connect first surface 181 and second surface 182.

[0085] The conductive member 18 is bonded to the cell 1A via a bonding material 50. The bonding material 50 is located between a first surface 181 of the conductive member 18 and the element unit 3A of one of the cells 1A, and between a second surface 182 of the conductive member 18 and the element unit 3A of the other cell 1A, and bonds the pair of cells 1A and the conductive member 18 facing each other across the conductive member 18. In addition, the third surfaces 183 and 184 are exposed to an oxidizing atmosphere, such as air.

[0086] The conductive member 18 has a base material 41, a polycrystalline film 42, and a coating layer 43. Each part constituting the conductive member 18 can be made of, for example, the same material as the conductive member 18 according to the first embodiment described above.

[0087] The polycrystalline film 42 is located on the substrate 41. The polycrystalline film 42 is located between the substrate 41 and the coating layer 43. The polycrystalline film 42 includes a plurality of chromium oxide particles 421 and a first element (see FIG. 4C). The first element is located between the chromium oxide particles 421, and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium.

[0088] In this way, since the conductive member 18 has the first element at a specific position in the polycrystalline film 42, it becomes difficult for the polycrystalline film 42 to grow, and therefore the conductive member 18 is less likely to experience an increase in internal resistance that accompanies the growth of the polycrystalline film 42. This makes it possible to reduce the deterioration in the power generation performance of the cell 1A, and therefore to reduce the deterioration in the power generation performance of the cell stack device 10A.

[0089] [Third embodiment] Fig. 8A is a perspective view showing an electrochemical cell according to a third embodiment, and Fig. 8B is a partial cross-sectional view of the electrochemical cell shown in Fig. 8A.

[0090] 8A, cell 1B, which is a flat-plate electrochemical cell, has an element portion 3B in which an anode 5, a solid electrolyte layer 6, and an air electrode 8 are stacked. In an electrochemical cell device in which a plurality of flat-plate cells are stacked, for example, the plurality of cells 1B are electrically connected by conductive members 91, 92, which are adjacent metal layers. The conductive members 91, 92 electrically connect adjacent cells 1B to each other and have gas flow paths for supplying gas to the anode 5 or the air electrode 8.

[0091] 8B, in this embodiment, the conductive member 92 has a gas flow path 94 that supplies gas to the air electrode 8. The conductive member 92 is bonded to the element section 3B (air electrode 8) via a bonding material 50. The conductive member 92 may be in direct contact with the element section 3B without the bonding material 50. In other words, in this embodiment, the conductive member 92 may be connected directly to the element section 3B without using the bonding material 50.

[0092] The conductive member 92 has a substrate 41, a polycrystalline film 42, and a coating layer 43. Each part constituting the conductive member 92 can be made of, for example, a material similar to the conductive member 18 described above.

[0093] The polycrystalline film 42 is located on the substrate 41. The polycrystalline film 42 is located between the substrate 41 and the coating layer 43. The polycrystalline film 42 includes a plurality of chromium oxide particles 421 and a first element (see FIG. 4C). The first element is located between the chromium oxide particles 421, and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium.

[0094] In this way, since the conductive member 18 has the first element at a specific position in the polycrystalline film 42, it becomes difficult for the polycrystalline film 42 to grow, and therefore the conductive member 18 is less likely to experience an increase in internal resistance that accompanies the growth of the polycrystalline film 42. This makes it possible to reduce the deterioration in the power generation performance of the cell 1B, and therefore to reduce the deterioration in the power generation performance of a cell stack device having a plurality of cells 1B.

[0095] 8C, the conductive member 91 has a gas flow path 93 that supplies fuel gas to the fuel electrode 5. The conductive member 91 is bonded to the element portion 3B (fuel electrode 5) via a bonding material 50. The conductive member 91 may be in direct contact with the element portion 3B without using the bonding material 50. In other words, the conductive member 91 may be directly connected to the element portion 3B without using the bonding material 50.

[0096] The conductive member 91 has a base material 41, a polycrystalline film 42, and a coating layer 43. Each part constituting the conductive member 91 can be made of a material such as the conductive member 92 (conductive member 18) described above.

[0097] The polycrystalline film 42 is located on the substrate 41. The polycrystalline film 42 is located between the substrate 41 and the coating layer 43. The polycrystalline film 42 includes a plurality of chromium oxide particles 421 and a first element (see FIG. 4C). The first element is located between the chromium oxide particles 421, and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium.

[0098] In this way, since the conductive member 91 has the first element at a specific position in the polycrystalline film 42, it becomes difficult for the polycrystalline film 42 to grow, and therefore the conductive member 91 is less likely to experience an increase in internal resistance that accompanies the growth of the polycrystalline film 42. This makes it possible to reduce the deterioration in the power generation performance of the cell 1B, and therefore to reduce the deterioration in the power generation performance of an electrochemical cell device having a plurality of cells 1B.

[0099] 8B and 8C, the conductive members 91, 92 are described as having the coating layer 43, but one or both of the conductive members 91, 92 may not have the coating layer 43. That is, the polycrystalline film 42 may come into contact with the gas supplied to the anode 5 or the cathode 8. Furthermore, in this embodiment, the conductive members 91, 92 are described as both having the polycrystalline film 42, but one of the conductive members 91, 92 may not have the polycrystalline film 42.

[0100] [Fourth embodiment] Fig. 9A is a cross-sectional view showing an example of an electrochemical cell according to the fourth embodiment. Figs. 9B and 9C are cross-sectional views showing another example of an electrochemical cell according to the fourth embodiment. Fig. 9D is an enlarged view of region C shown in Fig. 9A. Note that Fig. 9D can also be applied to the examples of Figs. 9B and 9C.

[0101] As shown in FIG. 9A, the cell 1C includes an element section 3C in which an anode 5, a solid electrolyte layer 6, and an air electrode 8 are stacked, and a support substrate 2. The support substrate 2 has through-holes or pores at a portion of the element section 3 that contacts the anode 5, and also includes a member 120 located outside the gas flow path 2a. The support substrate 2 allows gas to flow between the gas flow path 2a and the element section 3C. The support substrate 2 may be composed of, for example, one or more metal plates. The material of the metal plate may contain chromium. The metal plate may have a conductive coating layer. The support substrate 2 is a conductive member that electrically connects adjacent cells 1C. The element section 3C may be formed directly on the support substrate 2, or may be bonded to the support substrate 2 with a bonding material.

[0102] In the example shown in Fig. 9A, the side surface of the anode 5 is covered with a solid electrolyte layer 6, which airtightly seals a gas flow channel 2a through which the fuel gas flows. As shown in Fig. 9B, the side surface of the anode 5 may be covered and sealed with a dense sealing material 9. The sealing material 9 covering the side surface of the anode 5 may have electrical insulating properties. The material of the sealing material 9 may be, for example, glass or ceramics.

[0103] As shown in FIG. 9C, the gas flow path 2a of the support substrate 2 may be formed by a member 120 having projections and recesses.

[0104] In the fourth embodiment, the member 120 is joined to the air electrode 8 of another adjacent cell 1C via another conductive member such as an inter-cell connection member 60 and a bonding material 50. Note that the member 120 may also be in direct contact with the air electrode 8 of another cell 1C without the intervention of another conductive member.

[0105] 9D, the member 120 has a base material 41, a polycrystalline film 42, and a coating layer 43. Each part constituting the member 120 can be made of a material such as the previously described conductive member 18. Although detailed explanation using drawings is omitted, the inter-cell connection member 60 may also be the conductive member 18 having the base material 41, the polycrystalline film 42, and the coating layer 43.

[0106] The polycrystalline film 42 is located on the substrate 41. The polycrystalline film 42 is located between the substrate 41 and the coating layer 43. The polycrystalline film 42 includes a plurality of chromium oxide particles 421 and a first element (see FIG. 4C). The first element is located between the chromium oxide particles 421, and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium.

[0107] In this way, since the component 120 has the first element at a specific position in the polycrystalline film 42, it becomes difficult for the polycrystalline film 42 to grow, and therefore the component 120 is less likely to experience an increase in internal resistance due to the growth of the polycrystalline film 42. This reduces the deterioration in the power generation performance of the cell 1C, and therefore reduces the deterioration in the power generation performance of an electrochemical cell device having a plurality of cells 1C.

[0108] In this embodiment, the polycrystalline film 42 may be formed only on a part of the member 120. For example, in the example shown in Fig. 9C, the polycrystalline film 42 and the coating layer 43 may be provided only on a first portion 120a facing the air electrode 8 of another cell 1C and a second portion 120b facing the support substrate 2. The support substrate 2 may have the polycrystalline film 42 on a portion facing the fuel electrode 5 of the cell 1C.

[0109] <Other embodiments> Next, electrochemical cell devices according to other embodiments will be described.

[0110] In the above embodiments, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as examples of an "electrochemical cell," "electrochemical cell device," "module," and "module housing device." However, other examples may be an electrolysis cell, an electrolysis cell stack device, an electrolysis module, and an electrolysis device, respectively. The electrolysis cell has a first electrode layer and a second electrode layer, and decomposes water vapor into hydrogen and oxygen, or decomposes carbon dioxide into carbon monoxide and oxygen, when supplied with electric power. Furthermore, in the above embodiments, an oxide ion conductor or a hydrogen ion conductor is shown as an example of the electrolyte material of the electrochemical cell, but a hydroxide ion conductor may also be used. Such an electrolysis cell, an electrolysis cell stack device, an electrolysis module, and an electrolysis device can improve electrolysis performance.

[0111] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0112] As described above, the conductive member 18 according to the embodiment includes a substrate 41 and a polycrystalline film 42 that includes a plurality of chromium oxide particles 421 and is located on the substrate 41. The substrate 41 contains chromium. The polycrystalline film 42 includes a first element. The first element is located between the chromium oxide particles 421 and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium. This can reduce an increase in the internal resistance of the conductive member 18.

[0113] Moreover, the electrochemical cell according to the embodiment includes the element unit 3 and the above-described conductive member 18. The conductive member 18 is connected to the element unit 3. This makes it possible to provide an electrochemical cell that reduces the degradation of cell performance that accompanies an increase in internal resistance.

[0114] Furthermore, the electrochemical cell device according to the embodiment includes a cell stack 11 including a plurality of the electrochemical cells described above. This makes it possible to provide an electrochemical cell device that reduces performance degradation due to increased internal resistance.

[0115] Furthermore, the module 100 according to the embodiment includes the electrochemical cell device described above and a storage container 101 that stores the electrochemical cell device. This allows the module 100 to reduce performance degradation due to an increase in internal resistance.

[0116] Furthermore, the module housing device 110 according to the embodiment includes the above-described module 100, accessories for operating the module 100, and an exterior case for housing the module 100 and the accessories. This allows the module housing device 110 to reduce performance degradation due to increased internal resistance.

[0117] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0118] 1, 1A, 1B, 1C cells 3,3A,3B,3C element part 5 Fuel electrode 6 Solid electrolyte layer 7. Middle class 8 Air electrode 10 Cell stack device 11 Cell stack 12 Fixing member 13 Fixing material 14 Support member 15 Support 16 Gas Tank 17 End current collecting member 18 Conductive material 41 Base material 42 Polycrystalline film 43 Covering layer 100 modules 110 Module storage device

Claims

1. a chromium-containing substrate; a polycrystalline film comprising a plurality of chromium oxide particles and disposed on the substrate; and the polycrystalline film includes a first element; the first element is located between the chromium oxide particles and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium; the polycrystalline film has a grain boundary phase located between the chromium oxide grains, The grain boundary phase has a higher content of the first element than the chromium oxide particles. Conductive material.

2. a chromium-containing metal substrate; a polycrystalline film comprising a plurality of chromium oxide particles and disposed on the substrate; and the polycrystalline film includes a first element; the first element is located between the chromium oxide particles and has a first ionization energy and a free energy of formation of an oxide per mole of oxygen that are smaller than those of chromium; The substrate does not contain the first element. Conductive material.

3. The first element is one or more elements selected from Ce, Eu, Pr, and Zr. The conductive member according to claim 1 or 2.

4. The first element contained in the chromium oxide particles is less than 0.1 atomic %. The conductive member according to claim 1 or 2.

5. The grain boundary phase contains 0.1 atomic % or more of the first element. The conductive member according to claim 1 .

6. the polycrystalline film has a grain boundary phase located between the chromium oxide grains, The grain boundary phase contains 0.1 atomic % or more of the first element. The conductive member according to claim 2 .

7. The polycrystalline film includes first particles that include the first element and are located between the chromium oxide particles. The conductive member according to claim 1 or 2.

8. an oxide of the first element located on the polycrystalline film; The conductive member according to claim 1 or 2.

9. Further comprising a conductive coating layer positioned on the polycrystalline film. The conductive member according to claim 1 or 2.

10. an element portion; The conductive member according to claim 1 or 2, which is connected to the element portion. An electrochemical cell comprising:

11. An electrochemical cell device having a cell stack including the electrochemical cell of claim 10.

12. The electrochemical cell device according to claim 11; a container for housing the electrochemical cell device; A module comprising:

13. A module according to claim 12; Auxiliary equipment for operating the module; an exterior case that houses the module and the auxiliary equipment; A module housing device comprising:

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