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

Abstract

To provide an electrochemical cell, electrochemical cell device, module, and module housing device capable of improving cell performance.SOLUTION: The electrochemical cell includes a solid electrolyte layer, a porous first electrode, and a second electrode. The solid electrolyte layer has a first surface and a second surface located opposite the first surface. The first electrode contains metal particles and inorganic oxide particles and faces the first surface. The second electrode faces the second surface. In a cross-section along the thickness direction of the solid electrolyte layer, a maximum height roughness Rz of the second surface is smaller than a maximum height roughness Rz of the first surface.SELECTED DRAWING: Figure 3

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 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] Japanese Patent Application Laid-Open No. 2005-149796 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-174516 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional fuel cell stack devices have room for improvement in terms of power generation performance.

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

[0006] An electrochemical cell according to one aspect of the embodiment includes a solid electrolyte layer, a porous first electrode, and a second electrode. The solid electrolyte layer has a first surface and a second surface opposite the first surface. The first electrode includes metal particles and inorganic oxide particles and faces the first surface. The second electrode faces the second surface. In a cross section along the thickness direction of the solid electrolyte layer, the maximum height roughness Rz of the second surface is smaller than the maximum height roughness Rz of the first surface.

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

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

[0009] The module housing device of the present disclosure includes the module described above, an auxiliary device for operating the module, and an exterior case for housing the module and the auxiliary device. [Effects of the Invention]

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

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

[0012] Hereinafter, embodiments of an electrochemical cell, an electrochemical cell device, a module, and a module housing device disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0013] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0014] [First embodiment] <Electrochemical cell configuration> First, with reference to Figures 1A and 1B, an electrochemical cell according to a first embodiment will be described using an example of a solid oxide fuel cell. The electrochemical cell device may include a cell stack having a plurality of electrochemical cells. An electrochemical cell device having a plurality of electrochemical cells will be simply referred to as a cell stack device.

[0015] Fig. 1A is a plan view showing an example of an electrochemical cell according to a first embodiment. Fig. 1B is a cross-sectional view taken along line AA shown in Fig. 1A. Figs. 1A and 1B show enlarged views of parts of each component of the electrochemical cell. Hereinafter, the electrochemical cell may be simply referred to as a cell.

[0016] For ease of understanding, Figures 1A and 1B illustrate a three-dimensional Cartesian coordinate system including a Z axis, with the vertical upward direction as the positive direction and the vertical downward direction as the negative direction. This Cartesian coordinate system may also be shown in other drawings used in the following explanation. Furthermore, components similar to those in the electrochemical cells shown in Figures 1A and 1B are denoted by the same reference numerals, and their explanations will be omitted or simplified.

[0017] 1A and 1B, the cell 1 according to this embodiment includes an element section 3, a metal plate 23, and a flow path member 25. The element section 3 includes a fuel electrode 5, a solid electrolyte layer 6, and a cathode 8.

[0018] The fuel electrode 5 is a first electrode that comes into contact with the fuel gas, which is a reducing gas. The fuel electrode 5 is made of a gas-permeable porous material. The open porosity of the fuel electrode 5 may be, for example, in the range of 30% to 50%, and particularly 35% to 45%. The open porosity of the fuel electrode 5 may also be referred to as the porosity or void ratio of the fuel electrode 5.

[0019] The anode 5 contains metal particles such as Ni and inorganic oxide particles. The anode 5 may contain porous conductive ceramics, such as ceramics containing calcium oxide, magnesium oxide, or ZrO2 solid-solubilized with a rare earth element oxide, and Ni and / or NiO. The rare earth element oxide may contain, for example, 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 a rare earth element oxide is sometimes referred to as stabilized zirconia. The stabilized zirconia may include partially stabilized zirconia. The anode 5 may contain CeO2 solid-solubilized with Y, La, Nd, Gd, or Yb.

[0020] The solid electrolyte layer 6 is an electrolyte and transfers ions between the fuel electrode 5 and the air electrode 8. At the same time, the solid electrolyte layer 6 has gas barrier properties and makes it difficult for the fuel gas and oxygen-containing gas to leak.

[0021] The solid electrolyte layer 6 may be made of ceramics. The solid electrolyte layer 6 may contain one or both of Zr and Ce. The material of the solid electrolyte layer 6 may be, for example, ZrO2 in which 3 mol % to 15 mol % of a rare earth element oxide is dissolved. The rare earth element oxide may contain, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The solid electrolyte layer 6 may, for example, contain ZrO2 in which Yb, Sc, or Gd is dissolved, CeO2 in which La, Nd, or Yb is dissolved, BaZrO3 in which Sc, Y, or Yb is dissolved, or BaCeO3 in which Sc, Y, Gd, or Yb is dissolved.

[0022] The air electrode 8 is a second electrode that comes into contact with an oxygen-containing gas. The air electrode 8 has gas permeability. The open porosity of the air electrode 8 may be, for example, in the range of 20% to 50%, and particularly in the range of 30% to 50%. The open porosity of the air electrode 8 may also be referred to as the porosity of the air electrode 8.

[0023] 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.

[0024] The material of the air electrode 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. Examples of such composite oxides include La x Sr 1-x Co y Fe 1-y 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。

[0025] The element unit 3 may also have an intermediate layer 7 located between the solid electrolyte layer 6 and the air electrode 8. When the element unit 3 has the intermediate layer 7, the intermediate layer 7 makes it difficult for certain elements to diffuse. For example, 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 form.

[0026] The material of the intermediate layer 7 is not particularly limited as long as it generally prevents diffusion of elements between the air electrode 8 and the solid electrolyte layer 6. The material of the intermediate layer 7 may contain, 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).

[0027] The element section 3 may also have an adhesive 30 located between the fuel electrode 5 and the metal plate 23. The adhesive 30 bonds the element section 3 including itself to the metal plate 23, and fixes the element section 3 to the metal plate 23.

[0028] The adhesive 30 may be conductive. The adhesive 30 may contain, for example, conductive particles such as Ni and inorganic oxides such as TiO, rare earth element oxides (YO, CeO, etc.), and transition metal oxides (FeO, CuO, etc.). The adhesive 30 may contain metal particles and conductive oxide particles.

[0029] The adhesive material 30 may be gas permeable. When the adhesive material 30 is gas permeable, the adhesive material 30 may be positioned so as to cover the holes 32a, which will be described later.

[0030] A sealant 9 different from the solid electrolyte layer 6 may be positioned on the side surfaces of the adhesive 30 and the anode 5. The sealant 9 may be made of dense glass or ceramic. The sealant 9 may be made of, for example, amorphous glass or crystallized glass. Crystallized glass may be, for example, any of SiO2-CaO-based, MgO-B2O3-based, La2O3-B2O3-MgO-based, La2O3-B2O3-ZnO-based, or SiO2-CaO-ZnO-based materials, and particularly, SiO2-MgO-based materials. The sealant 9 may have electrical insulation properties. The sealant 9 may also be made of the same material as the solid electrolyte layer 6.

[0031] The adhesive 30 may be made of a single layer using a single material, or may be made of a laminated layer of multiple materials.

[0032] The cell 1 may further include a constraining layer located between the element section 3 and the adhesive material 30. The constraining layer cooperates with the solid electrolyte layer 6 to make the element section 3 less susceptible to warping or bending.

[0033] The material of the constraining layer exhibits a shrinkage rate similar to that of the material of the solid electrolyte layer 6 during firing. The material of the constraining layer may be the same as the material of the solid electrolyte layer 6. The element unit 3 obtained by sandwiching the material of the anode 5 of the element unit 3 between the material of the solid electrolyte layer 6 and the material of the constraining layer and firing the resulting element unit 3 has little warping or deformation.

[0034] The constraining layer may or may not be gas permeable. When the constraining layer has gas barrier properties comparable to those of the solid electrolyte layer 6, the constraining layer can be partially disposed so as not to impede the inflow of fuel gas to the anode 5.

[0035] The cell 1 may further include a gas diffusion layer. The gas diffusion layer is located between the fuel electrode 5 and the metal plate 23. The gas diffusion layer has gas permeability and allows the fuel gas flowing through a flow path 24 (described later) to pass through to the fuel electrode 5. The open porosity of the gas diffusion layer may be in the range of, for example, 30% to 50%, particularly 35% to 45%.

[0036] The material of the gas diffusion layer may be a porous conductive ceramic, such as a ceramic containing calcium oxide, magnesium oxide, or stabilized zirconia or partially stabilized zirconia in which a rare earth element oxide is solid-solved, and Ni and / or NiO. The rare earth element oxide may contain a plurality of rare earth elements selected from, for example, Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0037] The metal plate 23 has a first surface 231 and a second surface 232 located at both ends in the thickness direction (Y-axis direction). The first surface 231 is located so as to face the element portion 3. The second surface 232 is located on the opposite side of the first surface 231.

[0038] The metal plate 23 is electrically conductive. The metal plate 23 may be, for example, a metal member containing chromium. The metal plate 23 may be, for example, a stainless steel such as a ferritic stainless steel or an austenitic stainless steel having high heat resistance. The metal plate 23 may be, for example, a nickel-chromium alloy or an iron-chromium alloy. The metal plate 23 may contain, for example, a metal oxide. The metal plate 23 may have a coating covering the surface. The metal plate 23 may not have a coating on the surface.

[0039] The metal plate 23 also has a plurality of through holes 23a. The through holes 23a penetrate between the first surface 231 and the second surface 232. The fuel gas flowing through the flow path 24, which will be described later, is supplied to the fuel electrode 5 of the element section 3 through the through holes 23a. The diameter (opening diameter) of the through holes 23a may be, for example, 0.1 mm to 1.0 mm, particularly 0.3 mm to 0.6 mm. In a plan view of the metal plate 23 along the Y-axis direction, the area in which the through holes 23a are formed may have an opening ratio of, for example, 10% or more. The metal plate 23 may have a coating covering the wall surfaces of the through holes 23a. The metal plate 23 does not need to have a coating on the wall surfaces of the through holes 23a.

[0040] The metal plate 23 may be, for example, gas permeable. Also, the sealing material 9 may be located on the side surface of the metal plate 23.

[0041] The flow path member 25 is located on the second surface 232 side of the metal plate 23. The flow path member 25 is fixed and electrically joined by, for example, welding or the like at the contact portion with the second surface 232. The flow path member 25 may be fixed and electrically joined to the metal plate 23 with a conductive sealing material, brazing material, or the like. The space located between the metal plate 23 and the flow path member 25 is a flow path 24 through which the fuel gas flows. The fuel gas flowing through the flow path 24 permeates the metal plate 23 and is supplied to the anode 5. The metal plate 23 may have one or more protrusions protruding toward the flow path member 25. Furthermore, a sealing material 9 may be located on the side surface of the flow path member 25.

[0042] The flow path member 25 is further fixed and electrically connected to the current collecting member 27 by welding or the like. The current collecting member 27 may be fixed and electrically connected to the flow path member 25 by a conductive adhesive or brazing material. The current collecting member 27 is fixed and electrically connected to the air electrode 8 of an adjacent cell 1 via an adhesive (not shown). The space located between the current collecting member 27 and the flow path member 25 is a flow path 26 through which an oxygen-containing gas flows. The oxygen-containing gas flowing through the flow path 26 is supplied to the air electrode 8 of the adjacent cell 1 via the slits in the current collecting member 27 and the adhesive.

[0043] The flow path member 25 and the current collecting member 27 are made of a dense metal or alloy. The flow path member 25 makes it difficult for the fuel gas flowing through the flow path 24 and the oxygen-containing gas flowing through the flow path 26 to leak. The flow path member 25 and the current collecting member 27 may have a coating layer. For example, the surface of the flow path member 25 facing the flow path 24 may have a coating layer that is resistant to reduction, and the surface of the flow path member 25 facing the flow path 26 may have a coating layer that is resistant to oxidation. These coating layers may be electrically conductive.

[0044] Furthermore, the surface of the adhesive 30 that is not in contact with the metal plate 23 and the element section 3 may be covered with the sealing material 9 .

[0045] 1B, the shapes of the flow path member 25 and the current collecting member 27 are not limited to those shown in Fig. 1B. They may have any shape as long as they electrically connect adjacent cells 1 and make it difficult for the fuel gas and oxygen-containing gas to leak.

[0046] 2A and 2B are cross-sectional views showing another example of the electrochemical cell according to the first embodiment. As shown in Fig. 2A, a flow path member 25 may be integrated with a current collecting member 27 and have a first convex portion that protrudes toward an adjacent cell 1 along the Y-axis direction and a second convex portion that protrudes toward the opposite side from the first convex portion. Furthermore, as shown in Fig. 2B, a solid electrolyte layer 6 may cover the side surface of the fuel electrode 5 and airtightly seal a flow path 24 through which the fuel gas flows.

[0047] <Details of the electrochemical cell> Next, the electrochemical cell according to this embodiment will be described in further detail with reference to Fig. 3. Fig. 3 is an enlarged cross-sectional view of region R1 shown in Fig. 1B.

[0048] The electrochemical cell according to this embodiment has an element section 3. The element section 3 has a solid electrolyte layer 6, a fuel electrode 5, and a cathode 8.

[0049] The solid electrolyte layer 6 has a first surface 61 and a second surface 62 located opposite the first surface 61. The anode 5 contains metal particles and inorganic oxide particles. The anode 5 is a porous first electrode facing the first surface 61. The cathode 8 is a second electrode facing the second surface 62.

[0050] The solid electrolyte layer 6 of the electrochemical cell according to this embodiment has a first surface 61 and a second surface 62 that are different in shape. Specifically, as shown in Fig. 3, in a cross section along the thickness direction of the solid electrolyte layer 6, the maximum roughness in height Rz of the second surface 62 is smaller than the maximum roughness in height Rz of the first surface 61.

[0051] In this way, since the maximum height roughness Rz of the second surface 62 is smaller than the maximum height roughness Rz of the first surface 61, the O 2- Therefore, the electrochemical cell according to this embodiment improves power generation performance (cell performance).

[0052] Furthermore, the maximum height roughness Rz of the first surface 61 is larger than the maximum height roughness Rz of the second surface 62. The maximum height roughness Rz of the first surface 61 may be 1.2 times or more, particularly 2 times or more, the maximum height roughness Rz of the second surface 62. This increases the reaction area between the ion-conductive electrolyte material and the fuel electrode 5 on the first surface 61. Therefore, the electrochemical cell according to this embodiment improves power generation performance.

[0053] The maximum height roughness Rz of the second surface 62 may be 0.8 μm or less, and particularly 0.7 μm or less. 2-Therefore, the electrochemical cell according to this embodiment has a further improved power generation performance.

[0054] The first surface 61 may have a maximum height roughness Rz of 1.0 μm or more, particularly 1.2 μm or more. This further increases the reaction area between the ion-conductive electrolyte material and the fuel electrode 5 on the first surface 61. This further improves the power generation performance of the electrochemical cell according to this embodiment.

[0055] The element section 3 may further include an intermediate layer 7 located between the second surface 62 and the air electrode 8. The solid electrolyte layer 6 may contain Zr. The intermediate layer 7 may contain Ce and may have a dense portion 7a at the boundary 71 with the second surface 62. This increases the contact area between the intermediate layer 7 and the solid electrolyte layer 6, and 2- is easily transferred from the intermediate layer 7 to the solid electrolyte layer 6.

[0056] The boundary portion 71 refers to a region of the intermediate layer 7 that is 0.6 μm or less from the second surface 62. The dense portion 7a refers to a region having a porosity of 2% or less. Whether the intermediate layer 7 has the dense portion 7a or not can be confirmed by observing a cross section including the intermediate layer 7 and the solid electrolyte layer 6, for example, using a scanning electron microscope (SEM). The dense portion 7a may be located continuously over the entire boundary portion 71 facing the second surface 62, or may be located in a part of the boundary portion 71.

[0057] The maximum height roughness Rz of the first surface 61 and the second surface 62 can be measured as follows. A cross section including the intermediate layer 7, the solid electrolyte layer 6, and the anode 5 is mirror-polished. The obtained cross section is observed using an SEM, and a cross-sectional image is taken. The obtained cross-sectional image is subjected to image analysis using ImageJ, allowing the maximum height roughness Rz of the first surface 61 and the second surface 62 to be calculated.

[0058] <Configuration of electrochemical cell device> Next, an electrochemical cell device according to this embodiment using the above-described cell 1 will be described with reference to Figs. 4A to 4C. Fig. 4A is a perspective view showing an example of the electrochemical cell device according to the first embodiment. Fig. 4B is a cross-sectional view taken along line XX shown in Fig. 4A. Fig. 4C is a top view showing an example of the electrochemical cell device according to the first embodiment.

[0059] As shown in FIG. 4A, the cell stack device 10 includes a cell stack 11 having a plurality of cells 1 arranged (stacked) in the thickness direction of the element section 3 (the Y-axis direction shown in FIG. 1B), and a fixing member 12.

[0060] 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.

[0061] 4B, the support body 15 has insertion holes 15a into which the lower ends of the plurality of cells 1 are inserted. The lower ends of the plurality of cells 1 and the inner wall of the insertion holes 15a are joined with fixing material 13.

[0062] 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.

[0063] In the example shown in FIG. 4A, fuel gas is stored in an internal space 22 (see FIG. 4B) formed by a support 15, which is the support member 14, and a gas tank 16. A gas circulation pipe 20 is connected to the gas tank 16. The fuel gas is supplied to the gas tank 16 through this gas circulation pipe 20, and is supplied from the gas tank 16 to a flow path 24 (see FIG. 1B) 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.

[0064] 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.

[0065] The example shown in FIG. 4A includes two rows of cell stacks 11, two supports 15, and a gas tank 16. Each of the two rows of cell stacks 11 has a plurality of cells 1. Each cell stack 11 is fixed to a corresponding support 15. The gas tank 16 has two through-holes on its top surface. A support 15 is disposed in each through-hole. An internal space 22 is formed by one gas tank 16 and two supports 15. The cell stack device 10 may include only one cell stack 11, or may include three or more cell stacks 11.

[0066] 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 (Y-axis direction shown in FIG. 1B), 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 (X-axis direction shown in FIG. 1B).

[0067] 4B, 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.

[0068] 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.

[0069] 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.

[0070] 4B, a conductive member 18 is interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 electrically connects one adjacent cell 1 to the other adjacent cell 1 in series. More specifically, the conductive member 18 connects the fuel electrode 5 of one cell 1 to the air electrode 8 of the other cell 1. The conductive member 18 may be the current collecting member 27 shown in FIG. 1B, or may be a member separate from the current collecting member 27.

[0071] As shown in Fig. 4B, an end current collecting member 17 is electrically connected to the cell 1A located on the outermost side in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive part 19 that protrudes outward from the cell stack 11. The conductive part 19 collects electricity generated by power generation in the cells 1 and extracts it to the outside. Note that the end current collecting member 17 is not shown in Fig. 4A.

[0072] 4C, the cell stack device 10 may be a single battery in which two cell stacks 11A and 11B are connected in series. In this case, the conductive part 19 of the cell stack device 10 may have a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0073] 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.

[0074] 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.

[0075] Although not shown in Figures 4A to 4C, the cell stack device 10 may also be provided with a second gas tank at the top of the cell stack 11, which fixes the upper ends of multiple cells 1 and collects gas discharged from the flow path 24 inside the cells 1.

[0076] <module> Next, a module according to this embodiment using the above-described cell stack device 10 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.

[0077] 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.

[0078] 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.

[0079] The fuel gas produced in the reformer 102 is supplied to the flow path 24 of the cell 1 (see FIG. 1B) through the gas distribution pipe 20, the gas tank 16, and the support member 14.

[0080] When the cell stack device 10 includes a second gas tank above the cell stack 11, the reformer 102 may be disposed in a location other than above the cell stack device 10. The raw fuel supply pipe 103, the gas circulation pipe 20, etc. may be disposed appropriately depending on the arrangement of the cell stack device 10 and the reformer 102.

[0081] 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 as the cells 1 generate power.

[0082] In such a module 100, as described above, by accommodating the cell stack device 10, which has improved durability, the module 100 can be made to have improved durability.

[0083] <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.

[0084] 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.

[0085] 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.

[0086] In such a module housing device 110, as described above, the module housing chamber 115 is provided with the module 100 having improved durability, so that the module housing device 110 can have improved durability.

[0087] [Second embodiment] <Electrochemical cell configuration> Fig. 7A is a cross-sectional view showing an example of an electrochemical cell according to a second embodiment. Fig. 7B is a side view of an example of an electrochemical cell according to the second embodiment, viewed from the air electrode side. Fig. 7C is a side view of an example of an electrochemical cell according to the second embodiment, viewed from the interconnector side. Figs. 7A to 7C show enlarged views of parts of each component of the electrochemical cell.

[0088] 7A to 7C, cell 1 is a hollow, flat, elongated plate. As shown in Fig. 7B, the shape of the entire cell 1 as viewed from the side may be, 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 may be, for example, 1 mm to 5 mm.

[0089] 7A, the cell 1 includes a conductive support substrate 2, an element portion 3A, and an interconnector 4. The support substrate 2 is columnar and has a pair of opposing flat surfaces, a first flat surface n1 and a second flat surface n2, and a pair of arc-shaped side surfaces m connecting the first flat surface n1 and the second flat surface n2.

[0090] The element unit 3A is located on a first flat surface n1 of the support substrate 2. The element unit 3A has a fuel electrode 5 as a first electrode, a solid electrolyte layer 6, and a cathode 8 as a second electrode. The element unit 3A may also have an intermediate layer 7 located between the solid electrolyte layer 6 and the cathode 8.

[0091] 7B, 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 flat face n1. As shown in FIG. 7C, 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. 7A, 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.

[0092] The support substrate 2 has gas flow channels 2a therein through which gas flows. The example of the support substrate 2 shown in FIG. 7A has six gas flow channels 2a. The support substrate 2 is gas permeable, allowing the fuel gas flowing in the gas flow channels 2a to permeate to the anode 5. The support substrate 2 may be conductive. The conductive support substrate 2 collects electricity generated in the element section 3 to the interconnector 4.

[0093] The material of the support substrate 2 includes, for example, an iron-group metal component and an inorganic oxide. The iron-group metal component may be, for example, Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc (scandium), Y (yttrium), La (lanthanum), Nd (neodymium), Sm (samarium), Gd (gadolinium), Dy (dysprosium), and Yb (ytterbium).

[0094] Furthermore, the interconnector 4 is dense and prevents leakage of the fuel gas flowing through the gas flow passage 2a located inside the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2. The interconnector 4 may have a relative density of 93% or more, particularly 95% or more.

[0095] 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.

[0096] <Details of the electrochemical cell> Next, the electrochemical cell according to this embodiment will be described in further detail with reference to Fig. 8. Fig. 8 is an enlarged cross-sectional view of region R2 shown in Fig. 7A.

[0097] The electrochemical cell according to this embodiment includes an element part 3 A. The element part 3 A includes a solid electrolyte layer 6, a fuel electrode 5, and a cathode 8.

[0098] The solid electrolyte layer 6 has a first surface 61 and a second surface 62 located opposite the first surface 61. The anode 5 contains metal particles and inorganic oxide particles. The anode 5 is a porous first electrode facing the first surface 61. The cathode 8 is a second electrode facing the second surface 62.

[0099] In the electrochemical cell according to this embodiment, the maximum roughness in height Rz of the second surface 62 is smaller than the maximum roughness in height Rz of the first surface 61 in a cross section along the thickness direction T of the solid electrolyte layer 6, as shown in FIG.

[0100] In this way, since the maximum height roughness Rz of the second surface 62 is smaller than the maximum height roughness Rz of the first surface 61, the O 2-Therefore, the electrochemical cell according to this embodiment improves power generation performance (cell performance).

[0101] Furthermore, the maximum height roughness Rz of the first surface 61 is greater than the maximum height roughness Rz of the second surface 62. This increases the reaction area between the ion-conductive electrolyte material and the fuel electrode 5 on the first surface 61. This improves the power generation performance of the electrochemical cell according to this embodiment.

[0102] The maximum height roughness Rz of the first surface 61 may be 1.2 times or more, particularly 2 times or more, the maximum height roughness Rz of the second surface 62. This further improves the power generation performance of the electrochemical cell according to this embodiment.

[0103] The element section 3A may further include an intermediate layer 7 located between the second surface 62 and the air electrode 8. The solid electrolyte layer 6 may contain Zr. The intermediate layer 7 may contain Ce and may have a dense portion 7a at the boundary 71 with the second surface 62. This increases the contact area between the intermediate layer 7 and the solid electrolyte layer 6, and 2- is easily transferred from the intermediate layer 7 to the solid electrolyte layer 6.

[0104] [Third embodiment] Next, an electrochemical cell and an electrochemical cell device according to a third embodiment will be described with reference to FIGS. 9A to 10. FIG.

[0105] In the second embodiment described above, a so-called "vertical stripe type" electrochemical cell device was exemplified, in which only one element unit including a fuel electrode, a solid electrolyte layer, and an air electrode was 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.

[0106] 9A and 9B are cross-sectional views showing an example of an electrochemical cell device according to the third embodiment, and a transverse cross-sectional view showing an electrochemical cell according to the third embodiment.

[0107] 9A, in a cell stack device 10B, a plurality of cells 1 extend in a longitudinal direction L from a pipe 22a through which a fuel gas flows. Each cell 1 has a plurality of element portions 3B on a support substrate 2. A gas flow path 2a through which the fuel gas flows from the pipe 22a is provided inside the support substrate 2.

[0108] Moreover, the cells 1 are electrically connected to one another via connection members 31. The connection members 31 are located between the element portions 3B of the respective cells 1, and connect the adjacent cells 1 to one another.

[0109] 9B, the cell 1 according to this embodiment includes a support substrate 2, a pair of element portions 3B, and a sealing portion 32. The support substrate 2 is columnar and has a pair of opposing flat surfaces, a first flat surface n1 and a second flat surface n2, and a pair of arc-shaped side surfaces m connecting the first flat surface n1 and the second flat surface n2.

[0110] The pair of element portions 3B are located opposite each other on the first flat surface n1 and the second flat surface n2 of the support substrate 2. The sealing portion 32 is located so as to cover the side surface m of the support substrate 2.

[0111] Fig. 10 is an enlarged view of region R3 shown in Fig. 9B. The electrochemical cell according to this embodiment has an element section 3B. The element section 3B has a solid electrolyte layer 6, a fuel electrode 5, and a cathode 8.

[0112] The solid electrolyte layer 6 has a first surface 61 and a second surface 62 located opposite the first surface 61. The anode 5 contains metal particles and inorganic oxide particles. The anode 5 is a porous first electrode facing the first surface 61. The cathode 8 is a second electrode facing the second surface 62.

[0113] In the electrochemical cell according to this embodiment, the maximum roughness in height Rz of the second surface 62 is smaller than the maximum roughness in height Rz of the first surface 61 in a cross section along the thickness direction T of the solid electrolyte layer 6, as shown in FIG.

[0114] In this way, since the maximum height roughness Rz of the second surface 62 is smaller than the maximum height roughness Rz of the first surface 61, the O 2- Therefore, the electrochemical cell according to this embodiment improves power generation performance (cell performance).

[0115] Furthermore, the maximum height roughness Rz of the first surface 61 is greater than the maximum height roughness Rz of the second surface 62. This increases the reaction area between the ion-conductive electrolyte material and the fuel electrode 5 on the first surface 61. This improves the power generation performance of the electrochemical cell according to this embodiment.

[0116] The maximum height roughness Rz of the first surface 61 may be 1.2 times or more, particularly 2 times or more, the maximum height roughness Rz of the second surface 62. This further improves the power generation performance of the electrochemical cell according to this embodiment.

[0117] The element section 3B may further include an intermediate layer 7 located between the second surface 62 and the air electrode 8. The solid electrolyte layer 6 may contain Zr. The intermediate layer 7 may contain Ce and may have a dense portion 7a at the boundary 71 with the second surface 62. This increases the contact area between the intermediate layer 7 and the solid electrolyte layer 6, and 2- is easily transferred from the intermediate layer 7 to the solid electrolyte layer 6.

[0118] [Fourth embodiment] Fig. 11A is a perspective view showing an example of an electrochemical cell according to a fourth embodiment, and Fig. 11B is a partial cross-sectional view of the electrochemical cell shown in Fig. 11A.

[0119] 11A and 11B, cell 1 has an element section 3C having an anode 5, a solid electrolyte layer 6, and an air electrode 8, and conductive members 91 and 92. In an electrochemical cell device in which a plurality of flat cells are stacked, for example, the plurality of cells 1 are electrically connected by conductive members 91 and 92, which are adjacent metal layers. The conductive members 91 and 92 electrically connect adjacent cells 1 to each other and have gas flow paths for supplying gas to the anode 5 or the air electrode 8.

[0120] 11B, the cell 1 has a sealing material that airtightly seals the fuel gas flow path and the oxygen-containing gas flow path of the flat cell stack. The sealing material is a fixing member 96 for the cell, and has a bonding material 93 and support members 94 and 95 that serve as a frame. The bonding material 93 may be glass or a metal material such as silver solder.

[0121] The support member 94 may be a so-called separator that separates the fuel gas flow path from the oxygen-containing gas flow path. The material of the support members 94, 95 may be, for example, a conductive metal or an insulating ceramic. Either or both of the support members 94, 95 may be made of an insulating material. If the support member 94 is made of metal, the support member 94 may be integrated with the conductive member 92. If the support member 95 is made of metal, the support member 95 may be integrated with the conductive member 91.

[0122] One of the support members 94 and 95 is insulating, and electrically insulates the two conductive members 91 and 92 that sandwich the flat cell from each other.

[0123] 11B. The electrochemical cell according to this embodiment has an element section 3C. The element section 3C has a solid electrolyte layer 6, a fuel electrode 5, and a cathode 8.

[0124] The solid electrolyte layer 6 has a first surface 61 and a second surface 62 located opposite the first surface 61. The anode 5 contains metal particles and inorganic oxide particles. The anode 5 is a porous first electrode facing the first surface 61. The cathode 8 is a second electrode facing the second surface 62.

[0125] In the electrochemical cell according to this embodiment, the maximum roughness in height Rz of the second surface 62 is smaller than the maximum roughness in height Rz of the first surface 61 in a cross section along the thickness direction of the solid electrolyte layer 6, as shown in FIG.

[0126] In this way, since the maximum height roughness Rz of the second surface 62 is smaller than the maximum height roughness Rz of the first surface 61, the O 2- Therefore, the electrochemical cell according to this embodiment improves power generation performance (cell performance).

[0127] Furthermore, the maximum height roughness Rz of the first surface 61 is greater than the maximum height roughness Rz of the second surface 62. This increases the reaction area between the ion-conductive electrolyte material and the fuel electrode 5 on the first surface 61. This improves the power generation performance of the electrochemical cell according to this embodiment.

[0128] The maximum height roughness Rz of the first surface 61 may be 1.2 times or more, particularly 2 times or more, the maximum height roughness Rz of the second surface 62. This further improves the power generation performance of the electrochemical cell according to this embodiment.

[0129] The element section 3C may further include an intermediate layer 7 located between the second surface 62 and the air electrode 8. The solid electrolyte layer 6 may contain Zr. The intermediate layer 7 may contain Ce and may have a dense portion 7a at the boundary 71 with the second surface 62. This increases the contact area between the intermediate layer 7 and the solid electrolyte layer 6, and 2- is easily transferred from the intermediate layer 7 to the solid electrolyte layer 6.

[0130] [Other embodiments] In the above-described embodiments, a fuel cell, a fuel cell stack device, a fuel cell module, and a fuel cell device are shown as examples of an "electrochemical cell," "electrochemical cell device," "module," and "module housing device." However, other examples may be an electrolysis cell, an electrolysis cell stack device, an electrolysis module, and an electrolysis device, respectively. The electrolysis cell has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen, or carbon dioxide into carbon monoxide and oxygen, when supplied with electric power. Furthermore, in the above-described 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 (cell performance).

[0131] 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.

[0132] In one embodiment, (1) an electrochemical cell includes a solid electrolyte layer having a first surface and a second surface opposite the first surface; a porous first electrode including metal particles and inorganic oxide particles and facing the first surface; a second electrode facing the second surface; Equipped with In a cross section along the thickness direction of the solid electrolyte layer, the second surface has a maximum roughness in height Rz smaller than the maximum roughness in height Rz of the first surface.

[0133] (2) In the electrochemical cell of (1) above, the first surface may have a maximum height roughness Rz that is 1.2 times or more the maximum height roughness Rz of the second surface.

[0134] (3) In the electrochemical cell of (1) or (2) above, the second surface may have a maximum height roughness Rz of 0.8 μm or less.

[0135] (4) In the electrochemical cell of any one of (1) to (3) above, the first surface may have a maximum height roughness Rz of 1.0 μm or more.

[0136] (5) In the electrochemical cell of any one of (1) to (4) above, the solid electrolyte layer may be made of ceramics.

[0137] (6) In the electrochemical cell of any one of (1) to (5) above, the solid electrolyte layer may contain one or both of Zr and Ce.

[0138] (7) The electrochemical cell according to any one of (1) to (6) above, further comprising an intermediate layer located between the second surface and the second electrode, the solid electrolyte layer contains Zr, The intermediate layer may contain Ce and have a dense portion at the boundary with the second surface.

[0139] In one embodiment, (8) an electrochemical cell device has a cell stack including any one of the electrochemical cells (1) to (7) above.

[0140] In one embodiment, the module (9) comprises the electrochemical cell device (8) described above, and a container for housing the electrochemical cell device.

[0141] In one embodiment, the module storage device (10) includes the module (9) and Auxiliary equipment for operating the module; and an exterior case that houses the module and the auxiliary equipment.

[0142] 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]

[0143] 1 cell 3. Element section 5 Fuel electrode 6 Solid electrolyte layer 7. Middle class 8 Air electrode 9. Encapsulating materials 10 Cell stack device 23 Metal plate 30 Adhesive 100 modules 110 Module storage device

Claims

1. a solid electrolyte layer having a first surface and a second surface opposite the first surface; a porous first electrode including metal particles and inorganic oxide particles and facing the first surface; a second electrode facing the second surface; Equipped with In a cross section along the thickness direction of the solid electrolyte layer, the second surface has a maximum height roughness Rz smaller than the maximum height roughness Rz of the first surface. Electrochemical cell.

2. The maximum height roughness Rz of the first surface is 1.2 times or more the maximum height roughness Rz of the second surface.

10. The electrochemical cell of claim 1.

3. The second surface has a maximum height roughness Rz of 0.8 μm or less.

10. The electrochemical cell of claim 1.

4. The first surface has a maximum height roughness Rz of 1.0 μm or more.

10. The electrochemical cell of claim 1.

5. The solid electrolyte layer is made of ceramics.

10. The electrochemical cell of claim 1.

6. The solid electrolyte layer contains one or both of Zr and Ce.

10. The electrochemical cell of claim 1.

7. further comprising an intermediate layer located between the second surface and the second electrode; the solid electrolyte layer contains Zr, The intermediate layer contains Ce and has a dense portion at the boundary with the second surface.

10. The electrochemical cell of claim 1.

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

9. The electrochemical cell device according to claim 8 ; 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:

Images