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

Abstract

According to the present invention, an electrochemical cell comprises a gas transmission member, a metal member, and a conduction member. The gas transmission member is conductive and transmits a reducing gas. The metal member contains chromium and is connected to the gas transmission member. The conduction member is porous and is positioned between the gas transmission member and the metal member. The conduction member contains metal particles and a first element that 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 electrochemical cells, electrochemical cell devices, modules and module housing devices. [Background technology]

[0002] In recent years, various fuel cell stack devices including multiple fuel cell units have been proposed as next-generation energy sources. A fuel cell unit is a type of electrochemical cell that can generate electric power using a reducing 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] An electrochemical cell according to one aspect of the embodiment includes a gas permeable member, a metal member, and a conductive member. The gas permeable member is conductive and allows permeation of a reducing gas. The metal member contains chromium and is connected to the gas permeable member. The conductive member is porous and is located between the gas permeable member and the metal member. The conductive member contains metal particles and a first element having a first ionization energy and a free energy of formation of an oxide per mole of oxygen that is smaller than those of chromium.

[0005] The electrochemical cell device of the present disclosure also includes a cell stack including the electrochemical cell described above.

[0006] The module of the present disclosure includes the electrochemical cell device described above and a container that houses the electrochemical cell device.

[0007] The module housing device of the present disclosure includes the module described above, an auxiliary device for operating the module, and an exterior case for housing the module and the auxiliary device. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1A is a cross-sectional view showing an example of an electrochemical cell according to a first embodiment. [Figure 1B] FIG. 1B is a side view of an example of the electrochemical cell according to the first embodiment, viewed from the air electrode side. [Figure 1C] FIG. 1C is a side view of an example of the electrochemical cell according to the first embodiment, viewed from the interconnector side. [Figure 1D] FIG. 1D is a vertical cross-sectional view showing an example of the electrochemical cell according to the first embodiment. [Figure 2A] FIG. 2A is a cross-sectional view showing an example of the configuration of an interconnector and a conductive member. [Figure 2B] FIG. 2B is a cross-sectional view showing an example of the configuration of the interconnector and the conductive member. [Figure 2C] FIG. 2C is a cross-sectional view showing an example of the configuration of the interconnector and the conductive member. [Figure 3A] FIG. 3A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. [Figure 3B] FIG. 3B is a cross-sectional view taken along line XX shown in FIG. 3A. [Figure 3C] FIG. 3C is a top view showing an example of the electrochemical cell device according to the first embodiment. [Figure 4] FIG. 4 is an external perspective view illustrating an example of a module according to the first embodiment. [Figure 5] FIG. 5 is an exploded perspective view schematically illustrating an example of a module housing device according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing an electrochemical cell according to the second embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment. [Figure 8] FIG. 8 is an enlarged view of area A shown in FIG. [Figure 9A]FIG. 9A is a cross-sectional view showing an example of an electrochemical cell according to a third embodiment. [Figure 9B] FIG. 9B is a cross-sectional view showing another example of the electrochemical cell according to the third embodiment. [Figure 9C] FIG. 9C is a cross-sectional view showing another example of the electrochemical cell according to the third embodiment. [Figure 10A] FIG. 10A is an enlarged view showing an example of region B shown in FIG. 9A. [Figure 10B] FIG. 10B is an enlarged view showing another example of region B shown in FIG. 9A. [Figure 11A] FIG. 11A is a cross-sectional view showing an example of an electrochemical cell provided with a metal member having a recess on a first surface thereof. [Figure 11B] FIG. 11B is a plan view of the metal member shown in FIG. 11A as viewed from the first surface side. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of an electrochemical cell, an electrochemical cell device, a module, and a module housing device disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the disclosure is not limited to the embodiments described below.

[0010] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0011] [First embodiment] <Electrochemical cell configuration> First, with reference to Figures 1A to 1D, 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 have a cell stack including a plurality of electrochemical cells. An electrochemical cell device including a plurality of electrochemical cells will be simply referred to as a cell stack device.

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

[0013] 1A to 1D, 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 sides measuring 5 cm to 50 cm in the length direction L and 1 cm to 10 cm in the width direction W perpendicular to the length direction L. The thickness of the entire cell 1 in the thickness direction T is 1 mm to 5 mm.

[0014] 1A, the cell 1 includes a conductive support substrate 2, an element section 3, an interconnector 4, and a conductive member 9. The support substrate 2 is columnar and has a pair of opposing flat surfaces, a first surface n1 and a second surface n2, and a pair of arc-shaped side surfaces m connecting the first surface n1 and the second surface n2.

[0015] The element section 3 is provided 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 air electrode 8. In the example shown in FIG. 1A, a conductive member 9 is located on a second surface n2 of the support substrate 2. The cell 1 may also include an intermediate layer 7 between the solid electrolyte layer 6 and the air electrode 8.

[0016] 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 surfaces of a pair of arc-shaped side faces m of the cell 1. The conductive member 9 does not extend to the upper and lower ends of the cell 1 and is not exposed to the outside of the cell 1.

[0017] Each of the components constituting the cell 1 will be described below.

[0018] The support substrate 2 has gas flow channels 2a therein through which gas flows. The example of the support substrate 2 shown in FIG. 1A has six gas flow channels 2a. The support substrate 2 is gas permeable, allowing the fuel gas flowing 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 power generation element to the interconnector 4.

[0019] The material of the support substrate 2 includes, for example, an iron group metal component and an inorganic oxide. The iron group metal component may be, for example, Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0020] A commonly known material can be used for the anode 5. The anode 5 may be made of porous conductive ceramics, such as ceramics containing calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides, and Ni and / or NiO. The rare earth element oxides may contain, for example, multiple rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. Calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with rare earth element oxides is sometimes referred to as stabilized zirconia. Stabilized zirconia also includes partially stabilized zirconia.

[0021] 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 the fuel gas and oxygen-containing gas to leak.

[0022] 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.

[0023] The air electrode 8 is gas permeable. The open porosity of the air electrode 8 may be, for example, 20% or more, and particularly in the range of 30% to 50%.

[0024] 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.

[0025] 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。

[0026] Furthermore, when the element unit 3 includes the intermediate layer 7, the intermediate layer 7 functions as a diffusion suppression layer. When elements such as Sr (strontium) contained in the air electrode 8 diffuse into the solid electrolyte layer 6, a resistive layer such as SrZrO3 is formed in the solid electrolyte layer 6. The intermediate layer 7 suppresses the diffusion of Sr and makes it difficult for SrZrO3 and other electrically insulating oxides to form.

[0027] There are no particular restrictions on the material of the intermediate layer 7, as long as it is generally used as an element diffusion prevention layer between the air electrode 8 and the solid electrolyte layer 6. The material of the intermediate layer 7 includes, for example, cerium oxide (CeO2) in which rare earth elements other than Ce (cerium) are dissolved. Examples of such rare earth elements include Gd (gadolinium) and Sm (samarium).

[0028] The conductive member 9 is located between the interconnector 4 and the support substrate 2. The conductive member 9 has conductivity. The conductivity of the conductive member 9 is, for example, 1×10 2 S / m~1×10 7 It may be in the range of S / m.

[0029] The conductive member 9 also contains a first element. The conductive member 9 contains, for example, Ce. 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. In addition to Ce, other first elements include Eu, Pr, and Zr. The free energy of formation is also called 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 present in the conductive member 9 as an oxide of the element. Examples of such oxides of the first element include CeO2, EuO, PrO2, and ZrO2. Hereinafter, the oxide of the first element will be referred to as the "first oxide."

[0030] The conductive member 9 may contain, for example, one or more of the first elements. The conductive member 9 may also contain an element other than the first element. The conductive member 9 may contain, for example, CeO2 solid-solubilized with Gd (gadolinium), Sm (samarium), or the like, or may contain ZrO2 solid-solubilized with Y (yttrium), Yb (ytterbium), or the like, so-called stabilized zirconia or partially stabilized zirconia. The conductive member 9 may also contain, for example, a composite oxide containing the first element, such as Ce2Ti2O7.

[0031] The conductive member 9 also contains metal particles. The metal particles are, for example, metal or alloy particles. The metal particles may include, for example, metals or alloys such as Ni, Cu, Co, Fe, and Ti. Metals or alloys such as Ni, Cu, Co, Fe, and Ti have high electrical conductivity. These metals or alloys have high electrical conductivity, making it easier for the interconnector 4 to collect electricity generated in the element section 3. Metallic Ni, in particular, has high electrical conductivity and can maintain its electrical conductivity even in a high-temperature reaction atmosphere. Furthermore, Ni is contained in the support substrate 2, which can improve the bonding between the interconnector 4 and the support substrate 2.

[0032] The conductive member 9 may contain an inorganic oxide other than the first oxide. Examples of inorganic oxides contained in the conductive member 9 include oxides or composite oxides of Ni, Fe, Mn, Co, Zn, Ti, In, Sn, Al, Si, Mg, Ca, Sr, Ba, etc., and rare earth oxides such as Y, Yb, and Gd. The conductive member 9 may also contain rare earth oxides such as titanium oxide and yttrium oxide (YO), ABO3-type perovskite oxides, or composite oxides such as YTiO.

[0033] The ABO3-type perovskite oxide may include, for example, lanthanum chromite-based perovskite oxides (LaCrO3-based oxides), lanthanum strontium titanium-based perovskite oxides (LaSrTiO3-based oxides), etc. These perovskite oxides are electrically conductive and are resistant to reduction and oxidation even when in contact with fuel gases such as hydrogen-containing gases and oxygen-containing gases such as air.

[0034] The conductive member 9 may contain 20% by volume to 70% by volume of metal particles and 30% by volume to 80% by volume of the first oxide and inorganic oxide combined, relative to the total volume of the conductive member 9. The total volume of the conductive member 9 refers to the total volume of the metal particles, the first oxide, and the inorganic oxide. The first oxide may be 0.1% by volume to 40% by volume, or even 0.5% by volume to 30% by volume, relative to the total volume of the conductive member 9.

[0035] Furthermore, the conductive member 9 may be porous, and the open porosity may be in the range of, for example, 20% to 60%.

[0036] The thermal expansion coefficient of the conductive member 9 is, for example, 10×10 -6 / ℃~12×10 -6 / °C range. This makes the thermal expansion coefficient of conductive member 9 close to the thermal expansion coefficients of, for example, interconnector 4 and support substrate 2 that are in contact with conductive member 9, making interconnector 4 less likely to peel from support substrate 2 over the long term.

[0037] Furthermore, the thickness of the conductive member 9 can be set in the range of 10 μm to 200 μm, for example, from the viewpoint of adhesiveness and uniformity.

[0038] Furthermore, the interconnector 4 is a dense metal member, which makes it difficult for the fuel gas flowing through the gas flow channel 2a inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2 to leak. The interconnector 4 is fixed to the support substrate 2 having the gas flow channel 2a by a conductive member 9. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0039] The interconnector 4 contains chromium. The interconnector 4 is, for example, stainless steel. The interconnector 4 may contain, for example, a metal oxide.

[0040] Here, interconnector 4 and conductive member 9, which are metal members, will be described with reference to Figures 2A to 2C. Figures 2A to 2C are cross-sectional views showing configuration examples of the interconnector and conductive member.

[0041] As shown in FIG. 2A, the interconnector 4 may have a first layer 41 and a second layer 42. The second layer 42 may have a higher chromium content than the first layer 41, for example. The second layer 42 contains chromium oxide (Cr2O3), for example. When the interconnector 4 has the second layer 42 in this manner, the durability of the interconnector 4 is increased. Note that the interconnector 4 may partially have the second layer 42, or may not have the second layer 42. Furthermore, as shown in FIG. 2A, the second layer 42 may be located away from the conductive member 9, or may be in contact with the conductive member 9.

[0042] The surface of the interconnector 4 that contacts the conductive member 9 comes into contact with the fuel gas that has passed through the gas flow path 2a and the support substrate 2 and the conductive member 9. The fuel gas is a reducing gas that has reducing properties, and the second layer 42 usually does not grow easily on the surface of the interconnector 4 that contacts the conductive member 9. However, as will be described later, the fuel gas often contains water vapor. The second layer 42 may grow on the surface of the interconnector 4 that contacts the conductive member 9 due to the action of the water vapor contained in the fuel gas, and the internal resistance of the cell 1 may increase.

[0043] As described above, the conductive member 9 in contact with the interconnector 4 contains the first element. This makes it difficult for the second layer 42 to grow, and therefore the interconnector 4 can prevent an increase in internal resistance that accompanies the growth of the second layer 42. This can reduce a decrease in the battery performance of the cell 1. It can also prevent a decrease in the chromium ratio contained in the first layer 41 that accompanies the growth of the second layer 42. This improves the durability of the interconnector 4, and therefore the durability of the cell 1.

[0044] When the support substrate 2 and the interconnector 4 are bonded using a conductive member 9 that does not contain the first element and used at the operating temperature of a fuel cell, the thickness of the second layer 42 at the surface of the interconnector 4 that contacts the conductive member 9 is approximately several μm, for example, 4 μm. On the other hand, when a conductive member 9 that contains the first element, for example, CeO2, is used at the operating temperature of a fuel cell, the thickness of the second layer 42 is smaller than when a conductive member that does not contain the first element is used. For example, when the conductive member 9 contains 1 vol% CeO2, the thickness of the second layer 42 is approximately 3 μm, and when it contains 30 vol% CeO2, the thickness of the second layer 42 is 1 μm or less. The conductivity of Cr2O3 is approximately 1 S / m to 4 S / m.

[0045] For example, the conductivity of the conductive member 9 containing 50% by volume of Ni as metal particles and 50% by volume of TiO2 (titanium oxide) as inorganic oxide particles is 4×10 5The conductivity of the conductive member 9 containing 35 volume % of Ni, 35 volume % of TiO2 (titanium oxide), and 30 volume % of CeO2 (cerium oxide) as the first oxide is 7×10 2 S / m. Since the second layer 42 is thinned by the first element, the internal resistance of the cell using the conductive member 9 containing the first element becomes smaller than the internal resistance of the cell using the conductive member 9 not containing the first element.

[0046] 2B, the interconnector 4 may further include a coating layer 43.

[0047] Coat layer 43 contains elements different from those of first layer 41 and second layer 42, which are base materials. The surface of coat layer 43 is exposed to an oxidizing atmosphere. This makes it possible to reduce, for example, the release of chromium contained in interconnector 4. This improves the durability of interconnector 4, and therefore the durability of cell 1.

[0048] Furthermore, the coating layer 43 may contain, for example, an oxide containing Mn (manganese) and Co (cobalt). Hereinafter, the oxide containing Mn and Co will be referred to as the second oxide. The second oxide has electronic conductivity. The second oxide has higher conductivity than Cr2O3 and the first oxide. The second oxide may have, for example, a conductivity 100 times higher than that of Cr2O3. The molar ratio of Mn contained in the second oxide may be greater than the molar ratio of Co. The coating layer 43 may contain, for example, a second oxide in which the molar ratio of Mn, Co, and O is 1.66:1.34:4. By containing a second oxide having such a composition, the durability of the interconnector 4 can be improved compared to a coating layer 43 containing a second oxide in which the molar ratio of Mn, Co, and O is 1.5:1.5:4. The molar ratio of Mn, Co, and O can be calculated based on the identification of crystalline phases using an X-ray diffractometer (XRD). Furthermore, the second oxide may contain elements other than Mn and Co, such as Zn (zinc), Fe (iron), and Al (aluminum). The coating layer 43 may or may not contain the first element.

[0049] Furthermore, the coating layer 43 may be porous. The coating layer 43 may have a porosity of, for example, 5% or more and 40% or less. When the interconnector 4 has a porous coating layer 43 in this way, it is possible to alleviate stress that the interconnector 4 receives from the outside. This improves the durability of the interconnector 4, and therefore the durability of the cell 1 can be improved.

[0050] 2C, the conductive member 9 may have a laminated structure. The conductive member 9 may have a first layer 91 and a second layer 92.

[0051] The first layer 91 is in contact with the interconnector 4. The second layer 92 is in contact with the support substrate 2. The first layer 91 and the second layer 92 have different compositions. The first layer 91 contains a first element. Since the first layer 91 containing the first element is in contact with the interconnector 4, it becomes even more difficult for the second layer 42 of the interconnector 4 to grow, and therefore the interconnector 4 becomes even less susceptible to an increase in internal resistance that accompanies the growth of the second layer 42. This makes it possible to further reduce the deterioration of the battery performance of the cell 1.

[0052] The second layer 92 may or may not contain the first element. When the second layer 92 contains the first element, the content of the first element may be lower than that of the first layer 91.

[0053] 2C, the first layer 91 may be in contact with the interconnector 4 or may be spaced apart from the interconnector 4. When the first layer 91 is spaced apart from the interconnector 4, the first layer 91 may be located on the interconnector 4 side closer to the interconnector 4 than the support substrate 2. This makes it difficult for the second layer 42 of the interconnector 4 to grow, and therefore the interconnector 4 is even less susceptible to an increase in internal resistance that accompanies the growth of the second layer 42. This makes it possible to reduce a decrease in the battery performance of the cell 1.

[0054] <Configuration of cell stack device> Next, an electrochemical cell device according to this embodiment using the above-described cell 1 will be described with reference to Figures 3A to 3C. Figure 3A is a perspective view showing an example of the electrochemical cell device according to the first embodiment, Figure 3B is a cross-sectional view taken along line XX shown in Figure 3A, and Figure 3C is a top view showing an example of the electrochemical cell device according to the first embodiment.

[0055] As shown in FIG. 3A, 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.

[0056] The fixing member 12 has a fixing material 13 and a support member 14. The support member 14 supports the cell 1. The fixing material 13 fixes the cell 1 to the support member 14. The support member 14 also has a support 15 and a gas tank 16. The support 15 and the gas tank 16, which are the support member 14, are made of, for example, metal.

[0057] 3B, 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.

[0058] 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.

[0059] In the example shown in FIG. 3A, fuel gas is stored in an internal space 22 formed by a support 15, which is the support member 14, and a gas tank 16. A gas circulation pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas circulation pipe 20, and is supplied from the gas tank 16 to a gas flow path 2a (see FIG. 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated in a reformer 102 (see FIG. 4), which will be described later.

[0060] 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.

[0061] In the example shown in FIG. 3A, the cell stack device 10 includes two rows of cell stacks 11, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 has a plurality of cells 1. Each cell stack 11 is fixed to a respective support 15. The gas tank 16 has two through holes on its top surface. A respective 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.

[0062] The shape of the insertion hole 15a is, for example, an oval shape when viewed from above. For example, the length of the insertion hole 15a in the arrangement direction of the cells 1, i.e., the thickness direction T, is greater than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. For example, the width of the insertion hole 15a is greater than the length of the cell 1 in the width direction W (see FIG. 1A).

[0063] 3B, the joints between the inner walls of the insertion holes 15a and the lower ends of the cells 1 are filled with a fixing material 13 and solidified. 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 paths 2a of each cell 1 communicate with the internal space 22 of the support member 14 at their lower ends.

[0064] 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.

[0065] 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.

[0066] 3B, a connecting member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The connecting member 18 electrically connects the anode 5 of one adjacent cell 1 to the cathode 8 of the other adjacent cell 1 in series. More specifically, the connecting member 18 connects the interconnector 4 electrically connected to the anode 5 of one adjacent cell 1 to the cathode 8 of the other adjacent cell 1.

[0067] 3B, 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. 3A.

[0068] 3C, 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.

[0069] 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.

[0070] 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.

[0071] <module> Next, a module 100 according to an embodiment of the present disclosure using the above-described cell stack device 10 will be described with reference to Fig. 4. Fig. 4 is an external perspective view showing the module according to the first embodiment, with the front and rear surfaces, which are part of the storage container 101, removed and the cell stack device 10 of the fuel cell stored inside removed to the rear.

[0072] 4, the module 100 includes a storage container 101 and a cell stack device 10 housed in the storage container 101. A reformer 102 is disposed above the cell stack device 10.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] In such a module 100, as described above, by accommodating the cell stack device 10 that improves battery performance, the module 100 can be made to have improved battery performance.

[0077] <Module storage device> Fig. 5 is an exploded perspective view showing an example of a module housing device according to the first embodiment. The module housing device 110 according to this embodiment includes an outer case 111, the module 100 shown in Fig. 4, and auxiliary equipment (not shown). The auxiliary equipment operates the module 100. The module 100 and the auxiliary equipment are housed in the outer case 111. Note that some components are omitted in Fig. 5.

[0078] An exterior case 111 of a module accommodating device 110 shown in Fig. 5 has support columns 112 and an exterior plate 113. A partition plate 114 divides the interior of the exterior case 111 into upper and lower sections. The space above the partition plate 114 in the exterior case 111 is a module accommodating chamber 115 that accommodates the module 100, and the space below the partition plate 114 in the exterior case 111 is an accessory accommodating chamber 116 that accommodates accessory equipment for operating the module 100. Note that in Fig. 5, the accessory equipment accommodated in the accessory accommodating chamber 116 is omitted.

[0079] 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.

[0080] In such a module accommodating device 110, as described above, by providing the module 100 with improved battery performance in the module accommodating chamber 115, the module accommodating device 110 can be made to have improved battery performance.

[0081] 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.

[0082] [Second embodiment] Next, an electrochemical cell and an electrochemical cell device according to a second embodiment will be described with reference to FIGS.

[0083] 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.

[0084] FIG. 6 is a cross-sectional view showing an electrochemical cell according to the second embodiment, FIG. 7 is a cross-sectional view showing an example of an electrochemical cell device according to the second embodiment, and FIG. 8 is an enlarged view of region A shown in FIG. 7.

[0085] 6, the cell 1A according to the second embodiment includes a support substrate 2, a pair of element sections 3, and a sealing section 30. The support substrate 2 is columnar, having a pair of opposing flat surfaces, a first surface n1 and a second surface n2, and a pair of arc-shaped side surfaces m connecting the first surface n1 and the second surface n2.

[0086] The pair of element portions 3 are located opposite each other on the first surface n1 and the second surface n2 of the support substrate 2. The sealing portion 30 is located so as to cover the side surface m of the support substrate 2.

[0087] 7, in the cell stack device 10A, a plurality of cells 1A extend in a longitudinal direction L from a pipe 22a through which fuel gas flows. Each cell 1A has a plurality of element parts 3 on a support substrate 2. A gas flow path 2a through which fuel gas flows from the pipe 22a is provided inside the support substrate 2.

[0088] The cells 1A are electrically connected to one another via connecting members 31. The connecting members 31 are located between the element units 3 of the cells 1A, and connect the adjacent cells 1A together. Specifically, the connecting members 31 connect the air electrode 8 of the element unit 3 of one of the adjacent cells 1A to the fuel electrode 5 of the other cell 1A, and the interconnector 4, which are electrically joined together using a conductive member 9.

[0089] 8, the interconnector 4 is positioned so as to connect the element sections 3 adjacent to each other in the length direction L. The conductive member 9 is positioned between the interconnector 4 and the support substrate 2.

[0090] In this way, by bonding the interconnector 4 and the support substrate 2 using the conductive member 9, the interconnector 4 is less likely to peel off from the support substrate 2, improving the durability of the cell 1A, and thereby improving the battery performance of the cell stack device 10A.

[0091] [Third embodiment] FIG. 9A is a cross-sectional view showing an example of an electrochemical cell according to the third embodiment. FIGS. 9B and 9C are cross-sectional views showing another example of an electrochemical cell according to the third embodiment. Cell 1B includes a metal support having a metallic support substrate 2 and a flow path member 32, the metal support having a pair of opposing first and second surfaces n1 and n2, and an element unit 3. The element unit 3 is disposed on the first surface n1 of the support substrate 2 and includes an anode 5, a solid electrolyte layer 6, and a cathode 8. The anode 5 is located on the first surface n1 of the support substrate 2, the solid electrolyte layer 6 is located on the anode 5, and the cathode 8 is located on the solid electrolyte layer 6. The element unit 3 may include an intermediate layer between the solid electrolyte layer 6 and the cathode 8.

[0092] The metal support has a gas flow path 2a formed by a flow path member 32 and a second surface n2 opposite to the first surface n1 of the support substrate 2 on which the element section 3 is arranged.

[0093] The support substrate 2, which is a metal member, has gas permeability that allows the gas flowing through the gas flow channel 2a to pass through to the fuel electrode 5. The flow channel member 32 has gas barrier properties that prevent gas from passing between the gas flow channel 2a and the outside of the cell 1B, i.e., to prevent mixing of the fuel gas with an oxygen-containing gas such as air. In the example of Fig. 9A, the gas flow channel 2a is formed by the support substrate 2 and the flow channel member 32 having a U-shaped cross section.

[0094] The support substrate 2 and the flow path member 32 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 and the flow path member 32 electrically connect adjacent cells 1B to each other.

[0095] 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 the 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 sealant 33. The sealant 33 covering the side surface of the anode 5 may have electrical insulating properties. The material of the sealant 33 may be, for example, glass or ceramics.

[0096] As shown in FIG. 9C, the gas flow path 2a may be formed by a flow path member 32 having projections and recesses.

[0097] Fig. 10A is an enlarged view showing an example of region B shown in Fig. 9A, and Fig. 10B is an enlarged view showing another example of region B shown in Fig. 9A. In Fig. 10A and Fig. 10B, conductive member 9 electrically connects support substrate 2, which is a metal member, to fuel electrode 5. Thickness t1 of conductive member 9 can be set to, for example, a range of 10 µm to 200 µm.

[0098] The support substrate 2 may be a flat porous body having an open porosity of, for example, 30% or more, particularly in the range of 35% to 50%. Alternatively, the support substrate 2 may be a dense plate having a plurality of through-holes 2b penetrating the support substrate 2 in the thickness direction, as shown in Fig. 10B. When the support substrate 2 has such an open porosity or through-holes 2b, the fuel gas supplied to the gas flow channel 2a can reach the anode 5.

[0099] The support substrate 2, which is a metal member, may have a recess or a protrusion on at least one of the first surface n1 and the second surface n2. FIG. 11A is a cross-sectional view showing an example of an electrochemical cell including a metal member having a recess on its first surface. FIG. 11B is a plan view of the metal member shown in FIG. 11A, viewed from the first surface side. As shown in FIG. 11A, the support substrate 2, which is a metal member, has a recess 2c on its first surface n1. When the support substrate 2 has a recess 2c on its first surface n1, the recess 2c does not need to be in contact with the anode 5. That is, the cell 1B may have a gap between the recess 2c located on the first surface n1 of the support substrate 2 and the anode 5. In this case, the gap between the recess 2c on the first surface n1 and the anode 5 may be a gas flow path 2a.

[0100] In the cell 1B shown in FIG. 11A, the support substrate 2, which is a metal member, also serves as the flow path member 32 (see FIG. 9A), and the support substrate 2 may not be gas permeable between the first surface n1 and the second surface n2. The cell 1B shown in FIG. 11A also has a conductive member 9 between the first surface n1 and the anode 5. As shown in FIG. 11A, the conductive member 9 is located between the first surface n1, which does not have the recess 2c, and the anode 5. Alternatively, the conductive member 9 may be located between the first surface n1 and the anode 5 over the entire surface of the first surface n1 facing the anode 5. In such a case, the conductive member 9 located between the recess 2c and the anode 5 may be in contact with the anode 5 so as to be spaced apart from the support substrate 2, or may be in contact with the recess 2c of the support substrate 2 so as to be spaced apart from the anode 5.

[0101] The support substrate 2 is a metal member containing chromium, such as stainless steel. The support substrate 2 may have a second layer containing chromium oxide (Cr2O3), like the second layer 42 of the interconnector 4, which is the above-mentioned metal member. The conductive member 9 in contact with the support substrate 2 contains the first element. This makes it difficult for the second layer to grow, and therefore the support substrate 2 is less likely to experience an increase in internal resistance due to the growth of the second layer. This can reduce a decrease in the battery performance of the cell 1B. In this way, by using the conductive member 9 to bond the support substrate 2, which is a metal member, to the anode 5, peeling between the support substrate 2 and the anode 5 is less likely to occur, improving the durability of the cell 1B.

[0102] <Other variations> Next, other modifications of the embodiment will be described.

[0103] 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 electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device, respectively. The electrolytic cell has a hydrogen electrode and an oxygen electrode, and decomposes water vapor into hydrogen 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 the electrolyte material may also be a hydroxide ion conductor.

[0104] Furthermore, in the above embodiment, it has been described that the conductive member 9 is located between the interconnector 4 and the support substrate 2 and bonds the interconnector 4 and the support substrate 2, but as another example, the conductive member 9 may be located between the interconnector 4 and the fuel electrode 5 and bonds the interconnector 4 and the fuel electrode 5. The support substrate 2 and the fuel electrode 5 have in common the fact that they are electrically conductive and gas permeable members that allow fuel gas to pass through.

[0105] Furthermore, a gas seal member such as glass may be positioned at the end of the conductive member 9 so that the conductive member 9 is less likely to be exposed to the oxidizing atmosphere.

[0106] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0107] As described above, the electrochemical cell (cell 1) according to the embodiment includes a gas permeable member (support substrate 2 or fuel electrode 5) that is electrically conductive and allows permeation of a reducing gas, a metal member (interconnector 4) that contains chromium and is connected to the gas permeable member, and a conductive member 9 located between the gas permeable member and the metal member. The conductive member 9 is porous and contains metal particles and a first element whose first ionization energy and free energy of formation of its oxide per mole of oxygen are smaller than those of chromium. This improves the battery performance.

[0108] Moreover, the conductive member 9 according to the embodiment is located on the metal member side and has a first layer 91 containing the first element, which improves the battery performance.

[0109] Furthermore, the metal particles according to the embodiment contain Ni (nickel), which improves the battery performance.

[0110] Moreover, the first element according to the embodiment contains Ce (cerium), which improves the battery performance.

[0111] Moreover, the conductive member 9 according to the embodiment further contains titanium oxide, which improves the battery performance.

[0112] Moreover, the metal member according to the embodiment has a substrate facing the conductive member 9 and a coating layer 43 that covers the substrate and is exposed to an oxidizing atmosphere, thereby improving the battery performance.

[0113] Moreover, the electrochemical cell device (cell stack device 10) according to the embodiment has a cell stack 11 including the electrochemical cell (cell 1) described above. This makes it possible to provide an electrochemical cell device that can improve battery performance.

[0114] Moreover, the module 100 according to the embodiment includes the electrochemical cell device (cell stack device 10) described above and a storage container 101 that stores the electrochemical cell device (cell stack device 10). This allows the module 100 to have improved battery performance.

[0115] 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 improve battery performance.

[0116] 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]

[0117] 1,1A,1B cells 2 Support substrate 3. Element section 4 Interconnector 5 Fuel electrode 6 Solid electrolyte layer 7. Middle class 8 Air electrode 9 Conductive materials 10 Cell stack device 11 Cell stack 12 Fixing member 13 Fixing material 14 Support member 15 Support 16 Gas Tank 17 End current collecting member 18 Connecting member 100 modules 110 Module storage device

Claims

1. a gas permeable member that is electrically conductive and allows a reducing gas to permeate; a metal member containing chromium and connected to the gas permeable member; a porous conductive member positioned between the gas permeable member and the metal member; Equipped with The electrochemical cell, wherein the conductive member includes metal particles and a first element having a first ionization energy and a free energy of formation of an oxide per mole of oxygen that is less than that of chromium.

2. The conductive member is located on the metal member side and has a first layer containing the first element.

10. The electrochemical cell of claim 1.

3. The metal particles contain Ni (nickel).

10. The electrochemical cell of claim 1.

4. The first element includes Ce (cerium).

10. The electrochemical cell of claim 1.

5. The conductive member further contains titanium oxide.

10. The electrochemical cell of claim 1.

6. The metal member has a base material facing the conductive member and a coating layer covering the base material and exposed to an oxidizing atmosphere.

10. The electrochemical cell of claim 1.

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

8. The metal member is an interconnector that electrically connects adjacent element portions.

8. The electrochemical cell device of claim 7.

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

10. A module according to claim 9; 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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