Electrochemical cell, electrochemical cell device, module, and module storage device

Abstract

This electrochemical cell comprises a metal plate, a first electrode positioned on the metal plate, and a solid electrolyte layer positioned on the metal plate and the first electrode. The first electrode has a first surface facing the metal plate, a second surface positioned on the opposite side to the first surface, and a third surface connecting the first surface and the second surface. The solid electrolyte layer has a first portion located outside the contour of the first electrode in a plan view, a second portion located on the second surface, and a third portion located between the first portion and the second portion. The average thickness of the first portion is smaller than the average thickness of the second portion.

Description

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

[0001] The present disclosure relates to electrochemical cells, electrochemical cell devices, modules and module housing devices.

[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.

[0003] Patent No. 7394189 Patent No. 7394190

[0004] An electrochemical cell according to one aspect of the embodiment includes a metal plate, a first electrode located on the metal plate, and a solid electrolyte layer located on the metal plate and the first electrode. The first electrode has a first surface facing the metal plate, a second surface located opposite the first surface, and a third surface connecting the first surface and the second surface. The solid electrolyte layer has a first region located outside the outline of the first electrode in a plan view, a second region located on the second surface, and a third region located between the first region and the second region. The average thickness of the first region is smaller than the average thickness of the second region.

[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 also 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 also includes the module described above, an accessory configured to operate the module, and an exterior case housing the module and the accessory.

[0008] FIG. 1A is a plan view showing an example of an electrochemical cell according to an embodiment. FIG. 1B is a cross-sectional view taken along line A-A in FIG. 1A. FIG. 1C is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 2 is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 3A is a perspective view showing an example of an electrochemical cell device according to an embodiment. FIG. 3B is a cross-sectional view taken along line X-X in FIG. 3A. FIG. 3C is a top view showing an example of an electrochemical cell device according to an embodiment. FIG. 4 is an external perspective view showing an example of a module according to an embodiment. FIG. 5 is an exploded perspective view schematically showing an example of a module housing device according to an embodiment.

[0009] The above-described fuel cell stack device has room for improvement in terms of durability.

[0010] Therefore, there is a need to provide an electrochemical cell, an electrochemical cell device, a module, and a module housing device that can improve durability.

[0011] 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.

[0012] 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.

[0013] 1A and 1B, an electrochemical cell according to an 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.

[0014] Fig. 1A is a plan view showing an example of an electrochemical cell according to an embodiment. Fig. 1B is a cross-sectional view taken along line A-A 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.

[0015] 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 description. Furthermore, components similar to those in the electrochemical cells shown in Figures 1A and 1B are denoted by the same reference numerals, and their description will be omitted or simplified.

[0016] 1A, 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.

[0017] The anode 5 is a first electrode that comes into contact with the fuel gas, which is a reducing gas. The anode 5 has gas permeability. The open porosity of the anode 5 may be, for example, in the range of 30% to 50%, particularly 35% to 45%. The open porosity of the anode 5 may also be referred to as the porosity or void ratio of the anode 5.

[0018] A generally known material can be used for the fuel electrode 5. The fuel electrode 5 is made of a porous conductive ceramic, such as calcium oxide, magnesium oxide, or ZrO in which a rare earth element oxide is solid-solved. ２ and Ni and / or NiO may be used. 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 ZrO in which a rare earth element oxide is solid-solved may be used. ２ The stabilized zirconia may contain partially stabilized zirconia. The anode 5 is made of CeO in which La, Nd, or Yb is solid-solved. ２ may include:

[0019] The solid electrolyte layer 6 is a polycrystalline 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, making it difficult for leakage of fuel gas and oxygen-containing gas to occur.

[0020] The material of the solid electrolyte layer 6 is, for example, ZrO in which 3 mol % to 15 mol % of rare earth element oxide is dissolved. ２ 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 be, for example, ZrO in which Yb, Sc, or Gd is solid-solved. ２ and CeO in which La, Nd or Yb is solid-solved. ２ and BaZrO in which Sc or Yb is solid-solved. ３ and BaCeO in which Sc or Yb is solid-solved. ３ may include:

[0021] 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%, particularly 30% to 50%. The open porosity of the air electrode 8 may also be referred to as the porosity of the air electrode 8.

[0022] There are no particular limitations on the material of the air electrode 8 as long as it is a material that is generally used for air electrodes. ３ Conductive ceramics such as perovskite oxides may also be used.

[0023] The material of the air electrode 8 may be, for example, a composite oxide in which Sr (strontium) and La (lanthanum) coexist at the A site. Examples of such composite oxides include La ｘ Sr １－ｘ Co ｙ Fe １－ｙ O ３ , La ｘ Sr １－ｘ MnO ３ , La ｘ Sr １－ｘ FeO ３ , La ｘ Sr １－ｘ CoO ３Here, x is 0<x<1, and y is 0<y<1.

[0024] 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 a specific element to diffuse. For example, when a specific element such as Sr (strontium) contained in the air electrode 8 diffuses into the solid electrolyte layer 6, the solid electrolyte layer 6 is filled with SrZrO, which has a high electrical resistance. ３ The intermediate layer 7 makes it difficult for specific elements such as Sr to diffuse, thereby forming a resistive phase such as SrZrO ３ This makes it difficult for compounds such as

[0025] 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 is, for example, cerium oxide (CeO) in which rare earth elements other than Ce (cerium) are dissolved. ２ ) may be included. Examples of such rare earth elements include Gd (gadolinium) and Sm (samarium).

[0026] The cell 1 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 and the metal plate 23 together, and fixes the element section 3 to the metal plate 23.

[0027] The adhesive 30 may be conductive. For example, the adhesive 30 may be a mixture of conductive particles such as Ni and TiO ２ , rare earth element oxides (Y ２ O ３ , CeO ２ etc.), transition metal oxides (Fe ２ O ３ The inorganic oxide may include inorganic oxides such as SiO 2 , CuO, etc.

[0028] The adhesive 30 may be gas permeable. When the adhesive 30 is gas permeable, the adhesive 30 may be positioned so as to cover the holes 230, which will be described later.

[0029] The adhesive 30 may be formed as a single layer using a single material, or may be formed as a laminate of multiple materials.

[0030] The cell 1 may further include a constraining layer. The constraining layer may be located between the element portion 3 and the metal plate 23. The constraining layer cooperates with the solid electrolyte layer 6 to make the element portion 3 less susceptible to warping, bending, and the like.

[0031] 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.

[0032] 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 obstruct the inflow of fuel gas to the anode 5.

[0033] The cell 1 may further include a gas diffusion layer. The gas diffusion layer may be located between the anode 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 anode 5. The open porosity of the gas diffusion layer may be in the range of, for example, 30% to 50%, particularly 35% to 45%.

[0034] 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.

[0035] 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. The thickness of the metal plate 23 may be, for example, 0.1 mm to 1.0 mm, particularly 0.2 mm to 0.5 mm.

[0036] The metal plate 23 is electrically conductive. The metal plate 23 may be, for example, a member made of a metal 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.

[0037] The metal plate 23 also has a plurality of holes 230. The holes 230 are through-holes that penetrate between the first surface 231 and the second surface 232. The fuel gas flowing through the flow path 24 (described later) is supplied to the fuel electrode 5 of the element section 3 through the holes 230. The diameter (opening diameter) of the holes 230 may be, for example, 0.1 mm to 1.0 mm, particularly 0.3 mm to 0.6 mm. The aperture ratio of the region of the metal plate 23 where the holes 230 are formed, when viewed in a plan view along the Y-axis direction, may be, for example, 10% or more. The metal plate 23 may have a coating that covers the wall surfaces of the holes 230. The metal plate 23 may not have a coating on the wall surfaces of the holes 230.

[0038] The metal plate 23 may be gas permeable, for example. A sealing material different from the solid electrolyte layer 6 may be positioned on the side of the metal plate 23. The sealing material may be dense glass or ceramic. The sealing material may be, for example, amorphous glass or crystallized glass. Examples of crystallized glass include SiO ２ -CaO system, MgO-B ２ O ３ System, La ２ O ３ -B ２ O ３ -MgO-based, La ２ O ３ -B ２ O ３ -ZnO-based, SiO ２ -CaO-ZnO system materials, etc., may be used, and in particular SiO ２An MgO-based material may be used. The sealing material may have electrical insulating properties. The material of the sealing material may be the same as the material of the solid electrolyte layer 6.

[0039] 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 sealant, 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 flow path member 25 may have one or more protrusions protruding toward the metal plate 23. Furthermore, a sealant may be located on the side surface of the flow path member 25.

[0040] The flow path member 25 is further fixed and electrically joined to the current collecting member 27 by welding or the like. The current collecting member 27 may be fixed and electrically joined to the flow path member 25 by a conductive adhesive, brazing material, or the like. The current collecting member 27 is fixed and electrically joined 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.

[0041] 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. For example, the surface of the flow path member 25 facing the flow path 24 may have a reduction-resistant coating. Furthermore, the surface of the flow path member 25 facing the flow path 26 may have an oxidation-resistant coating. These coatings may be conductive.

[0042] 1B , the flow path member 25 and the current collecting member 27 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.

[0043] 1C is a cross-sectional view showing another example of an electrochemical cell according to the embodiment. As shown in FIG. 1C, 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.

[0044] 1A and 1B, the electrochemical cell according to this embodiment will be described in further detail. The cell 1 includes a metal plate 23, a fuel electrode 5 as a first electrode, and a solid electrolyte layer 6.

[0045] The metal plate 23 has an outer peripheral portion 23a and a central portion 23b. As shown in Fig. 1A, the outer peripheral portion 23a is a portion located outside the outline of the anode 5 when the cell 1 is viewed in plan from the cathode 8 side. The central portion 23b is a portion overlapping with the anode 5 when the cell 1 is viewed in plan from the cathode 8 side.

[0046] The anode 5 is located on the metal plate 23. The anode 5 has a first surface 51, a second surface 52, and a third surface 53. The first surface 51 faces the metal plate 23. The second surface 52 is located on the opposite side of the first surface 51. The third surface 53 is a side surface of the anode 5 that connects the first surface 51 and the second surface 52.

[0047] The solid electrolyte layer 6 is located on the metal plate 23 and on the anode 5. The solid electrolyte layer 6 has a first portion 61, a second portion 62, and a third portion 63.

[0048] The first portion 61 is located on the outer peripheral portion 23a of the metal plate 23. In other words, the first portion 61 is located outside the outline of the fuel electrode 5, which is the first electrode, in a plan view.

[0049] The second portion 62 is located on the second surface 52 of the anode 5. The third portion 63 is located between the first portion 61 and the second portion 62.

[0050] The average thickness of the first portion 61 of the solid electrolyte layer 6 is smaller than the average thickness of the second portion 62. When the average thickness of the first portion 61 is t1 and the average thickness of the second portion 62 is t2, t1 and t2 may have a relationship of (1 / 30) × t2 ≦ t1 < t2, for example. Furthermore, t1 and t2 may have a relationship of (1 / 25) × t2 ≦ t1 or a relationship of t1 < (1 / 3) × t2. This reduces the likelihood of cracks in the solid electrolyte layer 6, particularly in the first portion 61, and / or peeling of the first portion 61 from the metal plate 23, which are caused by a difference in thermal expansion between the solid electrolyte layer 6 and the metal plate 23. This improves the durability of the cell 1 according to this embodiment.

[0051] Furthermore, the average thickness of the third portion 63 located on the third surface 53 may be smaller than the average thickness of the second portion 62 overlapping the second surface 52 in a plan view. When the average thickness of the third portion 63 is t3, for example, t3 may have a relationship with t2 such that (1 / 30) × t2 ≦ t3 < t2. Furthermore, t3 may have a relationship with t2 such that (1 / 25) × t2 ≦ t3, or t3 < (1 / 3) × t2. This reduces the likelihood of cracks in the solid electrolyte layer 6, particularly in the third portion 63, and / or peeling of the third portion 63 from the third surface 53, which may be caused by a difference in thermal expansion between the solid electrolyte layer 6 and the anode 5. This improves the durability of the cell 1 according to this embodiment.

[0052] The average thickness of the first portion 61 is the average value of the thickness of the first portion 61. The average thickness of the second portion 62 is the average value of the thickness of the second portion 62. The average thickness of the third portion 63 is the average value of the thickness of the third portion 63. The thickness of the first portion 61 is the length from the interface between the metal plate 23 and the first portion 61 to the surface of the first portion 61 located in a direction perpendicular to the interface. The thickness of the second portion 62 is the length from the second surface 52 of the anode 5 to the surface of the second portion 62 located in a direction perpendicular to the second surface 52, or to the interface between the second portion 62 and the intermediate layer 7 or the cathode 8. The thickness of the third portion 63 is the length from the interface between the anode 5 and the third portion 63 to the surface of the third portion 63 located in a direction perpendicular to the interface. The thickness of the first portion 61 may be, for example, 0.4 μm to 3 μm. The thickness of the second portion 62 may be, for example, 0.4 μm to 3 μm, and the thickness of the third portion 63 may be, for example, 3 μm to 10 μm.

[0053] The solid electrolyte layer 6 is polycrystalline and has a plurality of crystallites. The average crystallite diameter in the first portion 61 may be smaller than the average crystallite diameter in the second portion 62. This makes it even less likely that cracks will occur in the solid electrolyte layer 6, particularly in the first portion 61, and / or that the first portion 61 will peel off from the metal plate 23, due to the difference in thermal expansion between the solid electrolyte layer 6 and the metal plate 23. This further improves the durability of the cell 1 according to this embodiment.

[0054] Furthermore, the average crystallite diameter in the third portion 63 may be smaller than the average crystallite diameter in the second portion 62. This reduces the likelihood of cracking of the solid electrolyte layer 6, particularly in the third portion 63, and / or peeling of the third portion 63 from the third surface 53, which may be caused by a difference in thermal expansion between the solid electrolyte layer 6 and the anode 5. This improves the durability of the cell 1 according to this embodiment.

[0055] Furthermore, the material of the third portion 63 may or may not penetrate into the voids of the fuel electrode 5, adhesive 30, etc. that are located above the central portion 23b and that are in contact with the third portion 63.

[0056] Furthermore, the surface roughness of the third portion 63 may be greater than the surface roughness of the first portion 61 and / or the second portion 62 .

[0057] Furthermore, the compositions of the first portion 61 to the third portion 63 of the solid electrolyte layer 6 may be the same, or any one of the elements may be different, or they may all be different. For example, the elements contained in the first portion 61 to the third portion 63 may be the same, or any one of the elements may be different, or they may all be different. Furthermore, when the elements contained in the first portion 61 to the third portion 63 are the same, the concentrations of the elements may all be the same, or any one of the elements may be different, or they may all be different.

[0058] For example, when the first portion 61 to the third portion 63 have the same composition, peeling, cracks, and the like are less likely to occur at the boundary between the first portion 61 and the third portion 63 and at the boundary between the third portion 63 and the second portion 62. This further improves the durability of the cell 1 according to this embodiment.

[0059] Furthermore, when the first to third regions 61 to 63 have different compositions, for example, the second region 62 may have a composition with high ion conductivity, and the first region 61 and the third region 63 may have a composition with high mechanical strength. This allows the cell 1 according to this embodiment to achieve both high cell performance and durability.

[0060] The average thicknesses (t1 to t3) and average crystallite diameters of the first to third regions 61 to 63 of the solid electrolyte layer 6 can be measured as follows. The solid electrolyte layer 6 includes the first to third regions 61 to 63, which are embedded in a resin and mirror-polished to obtain a cross section perpendicular to the Z-axis direction. The obtained cross section can be observed, for example, using a scanning electron microscope (SEM) to confirm the thickness of each region. Specifically, for example, any cross section perpendicular to the Z-axis direction of the cell 1 is observed using an SEM, and the thicknesses of 10 or more locations in each region are measured and the average value is taken as the average thickness. t1 to t3 may be calculated by averaging the thicknesses measured for the cross sections of any two or more regions. For example, when the length of the air electrode 8 in the Z-axis direction shown in FIG. 1A is L, the any two or more regions may be two regions located (⅓) × L away from a first end of the air electrode 8 in the Z-axis direction and a second end opposite the first end.

[0061] The average crystallite diameter of each portion can be confirmed by analyzing the obtained cross section, for example, by selected area electron diffraction (SAED) using a transmission electron microscope (TEM). Alternatively, the surface of each portion may be analyzed, for example, by X-ray diffraction (XRD). If the air electrode 8, intermediate layer 7, etc. are located on the second portion 62, the air electrode 8, intermediate layer 7, etc. may be removed by scraping, and then the surface of the second portion 62 may be analyzed by XRD.

[0062] The surface roughness and composition of the first region 61 to the third region 63 can be measured as follows. The surface roughness of each region can be confirmed by image analysis of a cross-sectional SEM image. Alternatively, the surface of each region can be measured at three or more locations using a laser microscope, and the average value can be used as the surface roughness of each region. The composition of each region can be confirmed by performing elemental analysis of the obtained cross-section using energy dispersive X-ray spectroscopy (EDS) or X-ray fluorescence analysis (XRF). The surface of each region (the surface of the second region from which the air electrode 8, intermediate layer 7, etc. have been removed) can also be measured using XRD to confirm the composition. Note that instead of a cross-section perpendicular to the Z-axis direction, a cross-section perpendicular to the X-axis direction can also be measured and analyzed.

[0063] Such a structure of the cell 1 including the solid electrolyte layer 6 according to the embodiment can be fabricated, for example, as follows. For example, green sheets for the adhesive 30, the anode 5, and the second region 62 are fabricated by a sheet molding method. A green sheet for the adhesive 30 is laminated on the first surface 231 located in the central portion 23b of the metal plate 23, and a green sheet for the anode 5 and a green sheet for the second region 62 are laminated on top of that to obtain a laminate. Alternatively, a laminate in which the green sheet for the anode 5 and the green sheet for the second region 62 are laminated may be fabricated in advance and fixed to the metal plate 23 using the adhesive 30.

[0064] Next, the material of the first portion 61 and the material of the third portion 63 are formed into films on the laminate using a vacuum film-forming method. That is, at least the first portion 61 and the third portion 63 may be films formed by the vacuum film-forming method. The second portion 62 may be a single layer formed only from a pre-fabricated green sheet, or may be a green sheet on which a film formed by the vacuum film-forming method is laminated.

[0065] Examples of the vacuum film formation method that can be used include physical vapor deposition (PVD) methods such as sputtering and vacuum deposition, chemical vapor deposition (CVD), and room temperature collision solidification.

[0066] The resulting laminate is fired at a temperature of, for example, about 1000°C to 1200°C, and then the intermediate layer 7 and the air electrode 8 are formed, thereby obtaining the cell 1 according to this embodiment. Note that the second portion 62 of the solid electrolyte layer 6 may be produced using a vacuum process such as sputtering, or a film formation method such as thermal spraying, instead of the sheet forming method described above.

[0067] 2 is a cross-sectional view showing another example of an electrochemical cell according to this embodiment. As shown in FIG. 2, the third surface 53, which is the side surface of the anode 5, may be inclined with respect to the Y-axis direction, which is the thickness direction. This makes it less likely that peeling, cracks, etc. will occur in the third portion 63 formed by the vacuum film deposition method. This improves the durability of the cell 1 according to this embodiment.

[0068] <Configuration of Electrochemical Cell Device> Next, an electrochemical cell device according to this embodiment using the above-described cell 1 will be described with reference to Figures 3A to 3C. Figure 3A is a perspective view showing an example of an electrochemical cell device according to an embodiment. Figure 3B is a cross-sectional view taken along line XX shown in Figure 3A. Figure 3C is a top view showing an example of an electrochemical cell device according to an embodiment.

[0069] As shown in Figure 3A, the cell stack device 10 comprises a cell stack 11 having multiple cells 1 arranged (stacked) in the thickness direction of the element section 3 (the Y-axis direction shown in Figure 1A), and a fixing member 12.

[0070] 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 metal and are electrically conductive.

[0071] 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 fixing material 13.

[0072] 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.

[0073] In the example shown in Fig. 3A, fuel gas is stored in an internal space 22 (see Fig. 3B) formed by a support body 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 may be generated in a reformer 102 (see Fig. 4), which will be described later.

[0074] 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.

[0075] The example shown in FIG. 3A 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. The 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.

[0076] The shape of the insertion hole 15a may be, 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. 1A ), may be greater than the distance between the two end current collecting members 17 located at both ends of the cell stack 11. For example, the width of the insertion hole 15a may be greater than the length of the cell 1 in the width direction (X-axis direction shown in FIG. 1A ).

[0077] 3B, the joints between the inner walls of the insertion holes 15a and the lower ends of the cells 1 are filled with and solidified with fixing material 13. 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.

[0078] 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.

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

[0080] 3B, 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.

[0081] 3B, 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 portion 19 that protrudes outward from the cell stack 11. The conductive portion 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.

[0082] 3C, the cell stack device 10 may be a single battery in which two cell stacks 11A, 11B are connected in series. In such a case, the conductive portion 19 of the cell stack device 10 may have a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0083] The positive electrode terminal 19A is a positive electrode when the power generated by the cell stack 11 is output to the outside. The positive electrode terminal 19A is electrically connected to the end current collector 17 on the positive electrode side 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. The negative electrode terminal 19B is electrically connected to the end current collector 17 on the negative electrode side of the cell stack 11B.

[0084] The connection terminal 19C electrically connects the end current collecting member 17 on the negative electrode side of the cell stack 11A to the end current collecting member 17 on the positive electrode side of the cell stack 11B.

[0085] Although not shown in Figures 3A to 3C, 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.

[0086] <Module> Next, a module 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 an example of a module according to an embodiment. Fig. 4 shows a state in which the front and rear surfaces, which are parts of the storage container 101, have been removed and the cell stack device 10 of the fuel cell stored inside has been removed to the rear.

[0087] 4, the module 100 includes a cell stack device 10 and a storage container 101 that stores the cell stack device 10. A reformer 102 may be disposed above the cell stack device 10.

[0088] 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 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.

[0089] 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.

[0090] Note that, 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, and the like may be disposed as appropriate depending on the arrangement of the cell stack device 10 and the reformer 102.

[0091] 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.

[0092] In such a module 100, as described above, the durability of the module 100 can be improved by accommodating the cell stack device 10, which has improved durability.

[0093] <Module Enclosure Device> Fig. 5 is an exploded perspective view schematically illustrating an example of a module enclosure device according to an embodiment. The module enclosure 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 outer case 111 accommodates the module 100 and the auxiliary equipment. Note that some components are omitted in Fig. 5.

[0094] 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. The space below the partition plate 114 in the exterior case 111 is an accessory accommodating chamber 116 that accommodates accessory equipment configured to operate the module 100. Note that in Fig. 5, the accessory equipment accommodated in the accessory accommodating chamber 116 is omitted from the illustration.

[0095] 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.

[0096] In such a module accommodating device 110, as described above, the module 100 with improved durability is provided in the module accommodating chamber 115, thereby making it possible to provide a module accommodating device 110 with improved durability.

[0097] [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. An electrolysis cell has a first electrode and a second electrode, and decomposes water vapor into hydrogen and oxygen, or decomposes carbon dioxide into carbon monoxide and oxygen, when supplied with electric power. Furthermore, in the above-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 electrolysis cells, electrolysis cell stack devices, electrolysis modules, and electrolysis devices can improve electrolysis performance and durability. Solid oxide fuel cells and electrolysis cells are collectively referred to as solid oxide electrochemical cells.

[0098] 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.

[0099] In one embodiment, (1) an electrochemical cell includes: a metal plate; a first electrode located on the metal plate and having a first surface facing the metal plate, a second surface located opposite the first surface, and a third surface connecting the first surface and the second surface; and a solid electrolyte layer located on the metal plate and the first electrode, wherein the solid electrolyte layer has a first region located outside the outline of the first electrode in a plan view, a second region located on the second surface, and a third region located between the first region and the second region, and an average thickness of the first region is smaller than an average thickness of the second region.

[0100] (2) In the electrochemical cell of (1) above, the average crystallite diameter in the first region may be smaller than the average crystallite diameter in the second region.

[0101] (3) In the electrochemical cell of (1) or (2) above, the average thickness of the third portion located on the third surface may be smaller than the average thickness of the second portion overlapping the second surface in a plan view.

[0102] (4) In the electrochemical cell of (3) above, the average crystallite diameter in the third region may be smaller than the average crystallite diameter in the second region.

[0103] (5) In the electrochemical cell of any one of (1) to (4) above, at least the first portion and the third portion may be films formed by a vacuum film-forming method.

[0104] In one embodiment, (6) the electrochemical cell device has a cell stack including any one of the electrochemical cells (1) to (5) above.

[0105] In one embodiment, (7) a module includes the electrochemical cell device of (6) above, and a container that houses the electrochemical cell device.

[0106] In one embodiment, (8) a module housing device includes the module of (7) above, an auxiliary device configured to operate the module, and an outer case housing the module and the auxiliary device.

[0107] 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.

[0108] REFERENCE SIGNS LIST 1 cell 3 element section 5 fuel electrode 6 solid electrolyte layer 7 intermediate layer 8 air electrode 10 cell stack device 23 metal plate 30 adhesive 51 first surface 52 second surface 53 third surface 61 first portion 62 second portion 63 third portion 100 module 110 module housing device

Claims

1. A metal plate and A first electrode located on the metal plate, having a first surface facing the metal plate, a second surface located on the opposite side of the first surface, and a third surface connecting the first surface and the second surface, The metal plate and the solid electrolyte layer located on the first electrode Equipped with, The solid electrolyte layer has a first portion located outside the contour of the first electrode in a plan view, a second portion located on the second surface, and a third portion located between the first portion and the second portion. The average thickness of the first part is smaller than the average thickness of the second part. Electrochemical cell.

2. The average crystallite size in the first region is smaller than the average crystallite size in the second region. The electrochemical cell according to claim 1.

3. The average thickness of the third portion located on the third surface is smaller than the average thickness of the second portion that overlaps with the second surface in a plan view. The electrochemical cell according to claim 1.

4. The average crystallite size in the third region is smaller than the average crystallite size in the second region. The electrochemical cell according to claim 3.

5. At least the first and third portions are films formed by vacuum deposition. The electrochemical cell according to claim 1.

6. A cell stack comprising an electrochemical cell according to any one of claims 1 to 5 Electrochemical cell apparatus.

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

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