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

Abstract

This electrochemical cell comprises a conductive first porous layer and a solid electrolyte layer. The first porous layer has a first surface and a second surface positioned on the side opposite from the first surface, and contains a metal material and an electrolyte material. The solid electrolyte layer faces the first surface and contains an electrolyte material. The first porous layer includes a first portion which includes the first surface, and a second portion which includes the second surface and which has a metal material content smaller than that of the first 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] JP 2014-235858 A JP 2014-40354 A

[0004] An electrochemical cell according to one aspect of the present invention includes a conductive first porous layer and a solid electrolyte layer. The first porous layer has a first surface and a second surface opposite the first surface, and contains a metal material and an electrolyte material. The solid electrolyte layer faces the first surface and contains the electrolyte material. The first porous layer has a first portion including the first surface and a second portion including the second surface, the second portion having a lower content of the metal material than the first portion.

[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 the first embodiment. FIG. 1B is a cross-sectional view showing an example of the A-A line shown in FIG. 1A. FIG. 2A is a cross-sectional view showing another example of the A-A line shown in FIG. 1A. FIG. 2B is a cross-sectional view showing another example of the A-A line shown in FIG. 1A. FIG. 3A is a cross-sectional view showing an enlarged example of a region R1 shown in FIG. 1B. FIG. 3B is a cross-sectional view showing another enlarged example of a region R1 shown in FIG. 1B. FIG. 4A is a perspective view showing an example of an electrochemical cell device according to the first embodiment. FIG. 4B is a cross-sectional view taken along the X-X line shown in FIG. 4A. FIG. 4C is a top view showing an example of an electrochemical cell device according to the first embodiment. FIG. 5 is an external perspective view showing an example of a module according to the first embodiment. FIG. 6 is an exploded perspective view schematically showing an example of a module housing device according to the first embodiment. FIG. 7A is a perspective view showing an example of an electrochemical cell according to the second embodiment. FIG. 7B is a partial cross-sectional view of the electrochemical cell shown in FIG. 7A. FIG. 8 is an enlarged cross-sectional view of a region R2 shown in FIG. 7B.

[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 a first embodiment. Fig. 1B is a cross-sectional view showing an example of a 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.

[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 and 1B, the cell 1 according to this embodiment includes an element section 3, a metal plate 23, and an adhesive 30. The element section 3 includes an anode 5, a solid electrolyte layer 6, and an cathode 8.

[0017] The anode 5 is an electrode that comes into contact with the fuel gas, which is a reducing gas. The anode 5 has gas permeability. "Gas permeability" means that gas can flow through open pores, voids, etc. The open porosity of the anode 5 may be, for example, 30% or more and 50% or less, particularly 35% or more and 45% or less. The open porosity of the anode 5 is sometimes 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. ２Alternatively, ceramics containing an electrolyte material such as Cr, Y, La, Nd, Sm, Gd, Dy, and Yb may be used. Calcium oxide, magnesium oxide, or ZrO in which a rare earth element oxide is solid-dissolved may be used. ２ The stabilized zirconia may contain partially stabilized zirconia. The anode 5 is made of CeO in which an oxide of La, Nd, or Yb is dissolved. ２ The anode 5 may contain, for example, 30% by volume or more of the metal material, where the total of the electrolyte material and the metal material is 100% by volume. The electrolyte material and the metal material contained in the anode 5 may be in the form of particles.

[0019] The solid electrolyte layer 6 is an electrolyte and transfers ions between the fuel electrode 5 and the air electrode 8. At the same time, the solid electrolyte layer 6 has gas barrier properties and makes it difficult for leakage of fuel gas and oxygen-containing gas to occur.

[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 first 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 ３ Here, x is 0<x<1, and y is 0<y<1.

[0024] The element unit 3 may also have a diffusion-preventing layer 7 located between the solid electrolyte layer 6 and the air electrode 8. When the element unit 3 has the diffusion-preventing layer 7, the diffusion-preventing 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 diffusion-preventing layer 7 makes it difficult for a specific element such as SrZrO ３ The diffusion suppression layer 7 makes it difficult for elements such as Sr to diffuse, thereby preventing the solid electrolyte layer 6 from forming a resistive phase such as SrZrO. ３ This makes it difficult for compounds such as

[0025] The material of the diffusion-preventing layer 7 is not particularly limited as long as it generally makes it difficult for elements to diffuse between the air electrode 8 and the solid electrolyte layer 6. The material of the diffusion-preventing 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 metal plate 23 has a surface 231 and a surface 232 located at both ends in the thickness direction (Y-axis direction). The surface 231 is located so as to face the adhesive 30. The surface 232 is located on the opposite side of the surface 231.

[0027] The metal plate 23 is electrically conductive. Alternatively, the metal plate 23 may be a member made of a metal containing chromium, for example. The metal plate 23 may be stainless steel, such as ferritic stainless steel or austenitic stainless steel, which has high heat resistance. The metal plate 23 may be a nickel-chromium alloy or an iron-chromium alloy, for example. The metal plate 23 may contain a metal oxide, for example. The metal plate 23 may have a coating covering the surface. The metal plate 23 may not have a coating on the surface. The coating may be, for example, an oxide film of a metal component contained in the metal plate 23. The coating may be a metal different from the metal component contained in the metal plate 23, or an oxide thereof.

[0028] The metal plate 23 also has a plurality of through holes 23a. The through holes 23a penetrate between the surface 231 and the surface 232. The fuel gas flowing through the flow path 24 (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 or more and 1.0 mm or less, particularly 0.3 mm or more and 0.6 mm or less. When viewed in a plan view along the Y-axis direction, the aperture ratio of the region of the metal plate 23 where the through holes 23a are formed may be, 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 may not have a coating on the wall surfaces of the through holes 23a.

[0029] The metal plate 23 may be a porous body having gas permeability, for example.

[0030] The adhesive 30 is positioned between the element section 3 and the metal plate 23. The adhesive 30 is positioned between the surface 231 of the metal plate 23 and the fuel electrode 5.

[0031] The flow path member 25 is located on the 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 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 is supplied to the anode 5 through the metal plate 23. The metal plate 23 may have one or more protrusions protruding toward the flow path member 25. Furthermore, a sealant 9 may be located on the side surface of the flow path member 25.

[0032] The flow path member 25 may be 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.

[0033] 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 flow path member 25 may have a reduction-resistant coating on the surface facing the flow path 24, and an oxidation-resistant coating on the surface facing the flow path 26. These coatings may be conductive.

[0034] Furthermore, the surface of the adhesive 30 that is not in contact with the metal plate 23 and the element portion 3 may be covered with the sealing material 9 .

[0035] 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.

[0036] 2A and 2B are cross-sectional views showing another example of the cross-section taken along line A-A in Fig. 1A. As shown in Fig. 2A, flow path member 25 may be integrated with current collecting member 27 and have a first convex portion that protrudes toward adjacent cells 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, solid electrolyte layer 6 may cover the side surface of fuel electrode 5 and airtightly seal flow path 24 through which fuel gas flows.

[0037] <Details of Electrochemical Cell> Next, the electrochemical cell according to this embodiment will be described in further detail. Fig. 3A is a cross-sectional view showing an example in which the region R1 shown in Fig. 1B is enlarged.

[0038] As shown in FIG. 3A , the electrochemical cell according to this embodiment includes an anode 5 and a solid electrolyte layer 6. The anode 5 is electrically conductive. The anode 5 has a first surface 51 and a second surface 52 located on the opposite side of the first surface 51. The anode 5 includes a metal material and an electrolyte material. The anode 5 is an example of a first porous layer that is electrically conductive. The metal material may be, for example, nickel. The electrolyte material may be, for example, ZrO in which a rare earth element oxide is solid-solved. ２ may be.

[0039] The solid electrolyte layer 6 is located so as to face the first surface 51. The solid electrolyte layer 6 includes an electrolyte material. The electrolyte material is, for example, ZrO ２ may be.

[0040] The anode 5 includes a first portion 5a and a second portion 5b. When the anode 5 is divided into two equal portions in the thickness direction, the first portion 5a is a portion that includes a first surface 51. The second portion 5b is a portion that includes a second surface 52. The second portion 5b has a lower content of metal material than the first portion 5a.

[0041] In this way, since the anode 5 has the second portion 5b having a lower content of metal material than the first portion 5a, cracks in the anode 5, particularly in the second portion 5b, and / or peeling of the anode 5 from the metal plate 23 (see FIG. 1B ) caused by, for example, a difference in thermal expansion between the anode 5 and the metal plate 23 are less likely to occur, thereby improving the durability of the electrochemical cell according to this embodiment.

[0042] The electrochemical cell according to this embodiment may further include an adhesive 30 positioned to face the second surface 52. The adhesive 30 may be conductive. The adhesive 30 may include a metal material and a first oxide different from the electrolyte material. The metal material and the first oxide included in the adhesive 30 may have a particle shape. The adhesive 30 is an example of a second porous layer having conductivity. The metal material may be, for example, nickel. The first oxide may be, for example, TiO ２ TiO ２ has a different composition from the electrolyte material. ２ has a thermal expansion coefficient different from that of the electrolyte material. This makes it less likely that cracks will occur in the anode 5, particularly in the second portion 5b, and / or that the anode 5 will peel off from the metal plate 23, which may be caused by a difference in thermal expansion between the anode 5 and the metal plate 23. This improves the durability of the electrochemical cell according to this embodiment.

[0043] The second portion 5b may also have a third portion 5c having a metallic material content of 15% by volume or less. The third portion 5c may be located within a range where L1, the distance from the second surface 52, is 4 μm or less. This reduces the likelihood of cracking of the anode 5, particularly in the third portion 5c, and / or peeling of the anode 5 from the metallic plate 23, due to, for example, a difference in thermal expansion between the anode 5 and the metallic plate 23. This improves the durability of the electrochemical cell according to this embodiment. The third portion 5c may be located over the entire second surface 52 or may be located partially. The third portion 5c may contain 4% by volume or more of the metallic material. This more easily maintains electrical connection between the anode 5 and the metallic plate 23 or the adhesive 30.

[0044] 3B is a cross-sectional view showing another example in which the region R1 shown in FIG. 1B is enlarged. As shown in FIG. 3B, the cell 1 may further include a diffusion layer 40. The diffusion layer 40 is electrically conductive. The diffusion layer 40 has a first surface 401 and a second surface 402 located on the opposite side of the first surface 401. The diffusion layer 40 includes a metal material and an oxide material. The metal material and the oxide material included in the diffusion layer 40 may be in the form of particles. The diffusion layer 40 is an example of a first porous layer having electrical conductivity. The metal material may be, for example, nickel. The oxide material may be, for example, calcium oxide, magnesium oxide, or ZrO in which a rare earth element oxide is solid-solved. ２ The diffusion layer 40 may contain, for example, 20% by volume or more of the metal material, with the total of the oxide material and the metal material being 100% by volume.

[0045] The solid electrolyte layer 6 is located so as to face the first surface 401. The solid electrolyte layer 6 includes an electrolyte material. The electrolyte material is, for example, ZrO ２ may be.

[0046] Diffusion layer 40 may be located between anode 5 and adhesive 30. Diffusion layer 40 is gas permeable and allows fuel gas flowing through flow path 24 (see FIG. 1B ) to pass through to anode 5. The open porosity of diffusion layer 40 may be, for example, 30% or more and 50% or less, particularly 35% or more and 45% or less.

[0047] The diffusion layer 40 includes a first portion 40a and a second portion 40b. When the diffusion layer 40 is divided into two equal portions in the thickness direction, the first portion 40a is a portion that includes a first surface 401. The second portion 40b is a portion that includes a second surface 402. The second portion 40b has a lower metal material content than the first portion 5a.

[0048] In this way, the diffusion layer 40 has the second portion 40b, which has a lower content of metal material than the first portion 40a, so that cracks in the diffusion layer 40, particularly in the first portion 40a, and / or peeling of the diffusion layer 40 from the metal plate 23, caused by, for example, a difference in thermal expansion between the diffusion layer 40 and the metal plate 23, are less likely to occur. This improves the durability of the cell 1 according to this embodiment.

[0049] The second portion 40b may also include a third portion 40c having a metal material content of 15% by volume or less. The third portion 40c may be located such that, when the distance from the second surface 402 is L2, L2 is 4 μm or less. This reduces the likelihood of cracks in the diffusion layer 40, particularly in the third portion 40c, and / or peeling of the diffusion layer 40 from the metal plate 23, due to, for example, a difference in thermal expansion between the anode 5 and the metal plate 23. This improves the durability of the cell 1 according to this embodiment. The third portion 40c may be located over the entire surface of the second surface 402 or may be located partially. The third portion 40c may contain 4% by volume or more of metal particles. This more reliably maintains electrical connection between the diffusion layer 40 and the metal plate 23 or the adhesive 30.

[0050] The diffusion layer 40 may also contain two or more oxide materials. The two or more oxide materials may be, for example, Y ２ O ３ The electrolyte may contain rare earth oxides such as Y and stabilized zirconia. The stabilized zirconia is an electrolyte material. ２ O ３ The rare earth oxides such as Y are examples of second oxides that are different from the electrolyte material. ２ O ３ The rare earth oxides such as Y have a different composition from the electrolyte material. ２ O ３The rare earth element oxides such as those mentioned above have a thermal expansion coefficient different from that of the electrolyte material. Two or more oxide materials may be contained in the diffusion layer 40, particularly in the second portion 40b. This reduces the likelihood of cracks in the diffusion layer 40, particularly in the second portion 40b, and / or peeling of the diffusion layer 40 from the metal plate 23, which may be caused by a difference in thermal expansion between the diffusion layer 40 and the metal plate 23. This improves the durability of the cell 1 according to this embodiment.

[0051] The diffusion layer 40 may contain a larger amount of rare earth elements than the fuel electrode 5. The diffusion layer 40 may contain particles of stabilized zirconia and particles of a rare earth element oxide.

[0052] The material of the diffusion layer 40 reduces the shrinkage of the anode 5 during firing, for example. This allows the degree of shrinkage of the anode 5 and the solid electrolyte layer 6 during firing to be similar, and therefore, the warping or deformation of the element portion 3 of the cell 1 having the diffusion layer 40 is reduced.

[0053] Furthermore, the material of the diffusion layer 40 is similar to the material of the anode 5, and the temperature at which the material of the diffusion layer 40 begins to shrink is close to that of the material of the anode 5. On the other hand, the rare earth element oxide contained in the diffusion layer 40 inhibits densification of the diffusion layer 40. As a result, the diffusion layer 40 has appropriate gas permeability while making the element portion 3 less likely to deform. Therefore, the cell 1 having the diffusion layer 40 has improved adhesion between the element portion 3 and the adhesive 30, and improved durability.

[0054] The cell 1 may also have a constraining layer 50. The constraining layer 50 may be located between the diffusion layer 40 and the adhesive 30. If the cell 1 does not have the diffusion layer 40, the constraining layer 50 may be located between the anode 5 and the adhesive 30. The constraining layer 50 may have a smaller porosity than the diffusion layer 40 or the anode 5.

[0055] The constraining layer 50 cooperates with the solid electrolyte layer 6 to make the element unit 3 less susceptible to warping, bending, etc. The material of the constraining layer 50 exhibits a similar shrinkage rate to the material of the solid electrolyte layer 6 during firing. The material of the constraining layer 50 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 50 and firing the resulting element unit 3 has reduced warping or deformation.

[0056] The constraining layer 50 may or may not be gas permeable. When the constraining layer 50 has gas barrier properties comparable to those of the solid electrolyte layer 6, the constraining layer 50 may have a plurality of through-holes that penetrate the cell 1 in the thickness direction (Y-axis direction) so as not to inhibit the inflow of fuel gas to the anode 5. When the constraining layer 50 has through-holes, a part of any of the adhesive 30, the diffusion layer 40, and the anode 5 may be located inside the through-holes.

[0057] The metallic material content in the anode 5 and the diffusion layer 40 can be measured as follows. For example, the polished cross-section of the cell 1, including the solid electrolyte layer 6, the anode 5, and optionally the diffusion layer 40, the adhesive 30, and the constrained layer 50, is photographed using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The photographed area is then subjected to semi-quantitative analysis (element mapping) of the elements contained in each region using an energy dispersive X-ray analyzer (EDX) or an electron probe microanalyzer (EPMA). Based on the results of the structural image and elemental mapping, the metallic material is distinguished from other materials, such as electrolyte material or oxide material. Furthermore, the metallic material content (volume %) in each region can be calculated using the average content (mass %) of the elements constituting the metallic material and the average content (mass %) of the elements constituting the other materials.

[0058] The arrangement and shape of the first portion 5a to the third portion 5c of the anode 5 and the first portion 40a to the third portion 40c of the diffusion layer 40 are obtained as follows: For example, a sheet-shaped solid electrolyte layer precursor containing the material of the solid electrolyte layer 6, a sheet-shaped anode precursor containing the material of the anode 5, and, if necessary, a sheet-shaped diffusion layer precursor containing the material of the diffusion layer 40 are prepared.

[0059] The anode 5 having the first portion 5a to the third portion 5c can be obtained, for example, as follows: A sheet-shaped first anode precursor containing 25 to 60 volume % of a metal material and a sheet-shaped second anode precursor containing 15 to 50 volume % of a metal material are prepared. A laminate is produced by sequentially stacking the first anode precursor and the second anode precursor on a solid electrolyte layer precursor. The produced laminate is fired, for example, in an oxidizing atmosphere at 1100 to 1450°C for 1 to 5 hours, to produce the anode 5 having the first portion 5a to the third portion 5c.

[0060] Alternatively, the laminate may be placed on a setter such as alumina so that the second anode precursor is in contact with the setter, and then fired. Alternatively, without using the second anode precursor, the solid electrolyte layer precursor and the first anode precursor may be stacked, and then the laminate may be placed on the setter so that the first anode precursor is in contact with the setter, and then fired. In this case, by appropriately adjusting the firing conditions, the metal component contained in the first anode precursor can be appropriately diffused from the surface of the first anode precursor to the setter, resulting in an anode 5 having first portions 5a to third portions 5c.

[0061] The diffusion layer 40 having the first portion 40a to the third portion 40c can be obtained, for example, as follows: A sheet-shaped first diffusion layer precursor containing 25% to 60% by volume of a metal material and a sheet-shaped second diffusion layer precursor containing 15% to 50% by volume of a metal material are prepared. A stack is produced by sequentially stacking the anode precursor, the first diffusion layer precursor, and the second diffusion layer precursor on the solid electrolyte layer precursor. The produced stack is fired, for example, in an oxidizing atmosphere at 1100°C to 1450°C for 1 hour to 5 hours, to produce the diffusion layer 40 having the first portion 40a to the third portion 40c.

[0062] Alternatively, the laminate may be placed on a setter such as alumina so that the second diffusion layer precursor is in contact with the setter, and then fired. In this case, without using the second diffusion layer precursor, the first diffusion layer precursor may be stacked on the anode precursor on the solid electrolyte layer precursor, and then the first diffusion layer precursor may be placed on the setter so that the first diffusion layer precursor is in contact with the setter, and then fired. In this case, by appropriately adjusting the firing conditions, the metal component contained in the first diffusion layer precursor can be appropriately diffused from the surface of the first diffusion layer precursor to the setter, resulting in a diffusion layer 40 having first portions 40a to third portions 40c.

[0063] Alternatively, a laminate may be formed by disposing a sheet-like constraining layer precursor containing the material of the constraining layer 50 and having a plurality of through-holes on the surface of the anode precursor that will become the second surface 52 of the anode 5 or on the surface of the diffusion layer precursor that will become the second surface 402 of the diffusion layer 40. The laminate may then be fired in an oxidizing atmosphere at 1100°C to 1450°C for 1 hour to 5 hours. The laminate may also be placed on a setter such as alumina so that the constraining layer precursor is in contact with the setter, and then fired. By adjusting the size and arrangement of the through-holes in the constraining layer precursor, the metal component contained in the anode precursor or diffusion layer precursor can be appropriately diffused from the surface of the anode precursor or diffusion layer precursor facing the through-holes in the constraining layer precursor to the setter, thereby obtaining an anode 5 having first portions 5a to third portions 5c, or a diffusion layer 40 having first portions 40a to third portions 40c.

[0064] The above-described method for producing the diffusion layer 40 and / or the fuel electrode 5 is merely an example, and they may be produced by any method.

[0065] <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 an electrochemical cell device according to the first embodiment. Fig. 4B is a cross-sectional view taken along line X-X shown in Fig. 4A. Fig. 4C is a top view showing an example of an electrochemical cell device according to the first embodiment.

[0066] As shown in Figure 4A, 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] In the example shown in Fig. 4A, fuel gas is stored in an internal space 22 (see Fig. 4B) 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 is generated in a reformer 102 (see Fig. 5), which will be described later.

[0071] 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.

[0072] 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. 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.

[0073] 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. 1A ), 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. 1A ).

[0074] 4B , 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.

[0075] 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.

[0076] Examples of the crystallized glass include SiO ２ -CaO system, MgO-B ２ O ３ System, La ２ O ３ -B ２ O ３ -MgO system, La ２ O ３ -B ２ O ３ -ZnO-based, SiO ２-CaO-ZnO system materials, etc., may be used, and in particular SiO ２ - MgO-based materials may also be used.

[0077] 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.

[0078] 4B, an end current collecting member 17 is electrically connected to the cell 1 positioned outermost in the arrangement direction of the multiple cells 1. The end current collecting member 17 is connected to a conductive portion 19 that protrudes outside 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. 4A.

[0079] 4C, 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.

[0080] 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.

[0081] 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.

[0082] Although not shown in Figures 4A to 4C, the cell stack device 10 may 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.

[0083] <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. 5. Fig. 5 is an external perspective view showing an example of a module according to the first embodiment. Fig. 5 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 pulled out to the rear.

[0084] 5, 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] <Module Enclosure Device> Fig. 6 is an exploded perspective view schematically illustrating an example of a module enclosure device according to the first embodiment. The module enclosure 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 outer case 111 accommodates the module 100 and the auxiliary equipment. Note that some components are omitted in Fig. 6.

[0091] 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. The space below the partition plate 114 in the exterior case 111 is an accessory accommodating chamber 116 that accommodates accessories configured to operate the module 100. Note that in Fig. 6, the accessories accommodated in the accessory accommodating chamber 116 are omitted from the illustration.

[0092] 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.

[0093] 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.

[0094] Second Embodiment Fig. 7A is a perspective view showing an example of an electrochemical cell according to a second embodiment, and Fig. 7B is a partial cross-sectional view of the electrochemical cell shown in Fig. 7A.

[0095] 7A and 7B , the cell 1 includes an element section 3A having an anode 5, a solid electrolyte layer 6, and a cathode 8, and conductive members 91 and 92. The element section 3A may further include a diffusion-suppressing layer 7 located between the solid electrolyte layer 6 and the cathode 8. 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 cathode 8.

[0096] 7B, 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.

[0097] 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.

[0098] 8 is an enlarged cross-sectional view of region R2 shown in FIG. 7B. As shown in FIG. 8, the electrochemical cell according to this embodiment includes an anode 5 as a conductive first porous layer, and a solid electrolyte layer 6. The anode 5 has a first surface 51 and a second surface 52 located on the opposite side of the first surface 51. The anode 5 includes a metal material and an electrolyte material. The anode 5 is an example of a conductive first porous layer. The metal material may be, for example, nickel. The electrolyte material may be, for example, ZrO in which a rare earth element oxide is solid-solved. ２ may be.

[0099] The solid electrolyte layer 6 is located so as to face the first surface 51. The solid electrolyte layer 6 includes an electrolyte material. The electrolyte material is, for example, ZrO ２ may be.

[0100] The anode 5 includes a first portion 5 a and a second portion 5 b. The first portion 5 a includes a first surface 51. The second portion 5 b includes a second surface 52. The second portion 5 b has a lower content of metal material than the first portion 5 a.

[0101] In this way, since the anode 5 has the second portion 5b having a lower content of metal material than the first portion 5a, cracks in the anode 5, particularly in the second portion 5b, and / or peeling of the anode 5 from the metal plate 23 (see FIG. 1B ) caused by, for example, a difference in thermal expansion between the anode 5 and the metal plate 23 are less likely to occur, thereby improving the durability of the electrochemical cell according to this embodiment.

[0102] The second portion 5b may also have a third portion 5c having a metal material content of 15% by volume or less. The third portion 5c may be located such that the distance L3 from the second surface 52 is 4 μm or less. This reduces the likelihood of cracking of the anode 5, particularly in the third portion 5c, and / or peeling of the anode 5 from the conductive member 91, due to, for example, a difference in thermal expansion between the anode 5 and the conductive member 91. This improves the durability of the electrochemical cell according to this embodiment. The third portion 5c may be located over the entire second surface 52 or may be located partially. The third portion 5c may also be located in the first portion 5a.

[0103] 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 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 durability. Solid oxide fuel cells and electrolysis cells are collectively referred to as solid oxide electrochemical cells.

[0104] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0105] In one embodiment, (1) an electrochemical cell includes: a conductive first porous layer having a first surface and a second surface opposite to the first surface, the first porous layer including a metal material and an electrolyte material; and a solid electrolyte layer facing the first surface and including the electrolyte material, wherein the first porous layer has a first portion including the first surface and a second portion including the second surface, the second portion having a lower content of the metal material than the first portion.

[0106] (2) In the electrochemical cell of (1) above, the second region may have a third region in which the content of the metal material is 15% by volume or less.

[0107] (3) In the electrochemical cell of (2) above, the third portion may be located within a range of a distance of 4 μm or less from the second surface.

[0108] (4) The electrochemical cell of any one of (1) to (3) above may further include a conductive second porous layer facing the second surface and containing the metal particles and a first oxide different from the electrolyte material.

[0109] (5) In the electrochemical cell of any one of (1) to (4) above, the second portion may further include a second oxide different from the electrolyte material.

[0110] In one embodiment, (6) the electrochemical cell device has a cell stack including any one of the electrochemical cells (1) to (5) above.

[0111] In one embodiment, (7) a module includes the electrochemical cell device of (6) above, and a container that houses the electrochemical cell device.

[0112] 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.

[0113] 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.

[0114] REFERENCE SIGNS LIST 1 cell 3 element portion 5 fuel electrode 5a first portion 5b second portion 6 solid electrolyte layer 8 air electrode 9 sealing material 10 cell stack device 23 metal plate 30 adhesive material 51 first surface 52 second surface 100 module 110 module housing device

Claims

1. An electrochemical cell comprising: a conductive first porous layer having a first surface and a second surface opposite the first surface, the first porous layer containing a metallic material and an electrolyte material; and a solid electrolyte layer facing the first surface and containing the electrolyte material, wherein the first porous layer has a first portion including the first surface and a second portion including the second surface, the second portion having a lower content of the metallic material than the first portion.

2. The electrochemical cell according to claim 1, wherein the second portion has a third portion in which the content of the metal material is 15% by volume or less.

3. The electrochemical cell according to claim 2, wherein the third portion is located within a range of 4 μm or less from the second surface.

4. The electrochemical cell according to any one of claims 1 to 3, further comprising a conductive second porous layer facing the second surface and containing the metal material and a first oxide different from the electrolyte material.

5. An electrochemical cell according to any one of claims 1 to 4, wherein the second region further contains a second oxide different from the electrolyte material.

6. An electrochemical cell device having a cell stack comprising the electrochemical cell according to any one of claims 1 to 5.

7. A module comprising the electrochemical cell device according to claim 6 and a container that houses the electrochemical cell device.

8. A module housing device comprising: a module according to claim 7; an accessory configured to operate said module; and an outer case housing said module and said accessory.

Images