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

Abstract

This electrochemical cell comprises a metal plate, an element part, and an intermediate layer. The metal plate has a first surface, and a second surface positioned on the reverse side from the first surface. The element part has: a first electrode which faces the first surface; a solid electrolyte layer; and a second electrode which is positioned on the reverse side from the first electrode with the solid electrolyte layer sandwiched therebetween. The intermediate layer is positioned between the first surface and the first electrode. The intermediate layer has a void which overlaps with at least a portion of the contour of the element part in a plan view from the second electrode side.

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] International Publication No. 2020 / 218431

[0004] An electrochemical cell according to one aspect of the embodiment includes a metal plate, an element unit, and an intermediate layer. The metal plate has a first surface and a second surface opposite the first surface. The element unit includes a first electrode facing the first surface, a solid electrolyte layer, and a second electrode opposite the first electrode across the solid electrolyte layer. The intermediate layer is located between the first surface and the first electrode. When viewed in plan from the second electrode side, the intermediate layer has a gap that overlaps at least a portion of the outline of the element unit.

[0005] An electrochemical cell device according to one aspect of the embodiment 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 cross-sectional view showing an example of an electrochemical cell according to an embodiment. FIG. 1B is an enlarged cross-sectional view of a portion of the electrochemical cell shown in FIG. 1A. FIG. 2 is a plan view of an example of an electrochemical cell according to an embodiment, viewed from the element portion side. FIG. 3 is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 4A is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 4B is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 4C is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 4D is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 4E is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 4F is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. FIG. 5A is a perspective view showing an example of an electrochemical cell device according to an embodiment. FIG. 5B is a cross-sectional view taken along line X-X shown in FIG. 5A. FIG. 5C is a top view showing an example of an electrochemical cell device according to an embodiment. FIG. 6 is an external perspective view showing an example of a module according to an embodiment. FIG. 7 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 cross-sectional view showing an example of an electrochemical cell according to an embodiment. Fig. 1B is a cross-sectional view showing an enlarged portion of the electrochemical cell shown in Fig. 1A. Note that Figs. 1A and 1B show enlarged portions 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, an intermediate layer 4, and a metal plate 32. The element section 3 includes an anode 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, 30% or more and 50% or less, particularly 35% or more and 45% or less. 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. ２and 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 solid oxide electrolyte. The solid electrolyte layer 6 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, 20% to 50%, in particular 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 section 3 may also have a diffusion suppression layer (not shown) located between the solid electrolyte layer 6 and the air electrode 8. A specific element such as Sr (strontium) contained in the air electrode 8 is likely to diffuse into the solid electrolyte layer 6. 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 becomes SrZrO ３ The diffusion suppression layer makes it difficult for elements such as Sr to diffuse, resulting in the formation of a resistance layer such as SrZrO. ３ This makes it difficult for a resistive layer such as the above to form.

[0025] The material of the diffusion barrier layer is not particularly limited as long as it generally makes it difficult for a specific element such as Sr to diffuse. The material of the diffusion barrier layer is, for example, cerium oxide (CeO) in which a rare earth element other than Ce (cerium) is dissolved. ２ ) may be included. Examples of such rare earth elements include Gd (gadolinium) and Sm (samarium).

[0026] The intermediate layer 4 is located between the first surface 321 of the metal plate 32 and the element portion 3. The intermediate layer 4 bonds the element portion 3 and the metal plate 32 together, and fixes the element portion 3 to the metal plate 32.

[0027] The intermediate layer 4 is electrically conductive. For example, the intermediate layer 4 is made of conductive particles such as Ni and TiO ２ , rare earth oxides (e.g., Y ２O ３ , CeO ２ etc.), transition metal oxides (e.g., Fe ２ O ３ The inorganic oxide may include inorganic oxides such as SiO 2 , CuO, etc.

[0028] The intermediate layer 4 has gas permeability. The intermediate layer 4 may be positioned so as to cover an opening 32a, which will be described later.

[0029] The intermediate layer 4 may be a single layer made of a single material, or may be a laminate made of multiple materials. The intermediate layer 4 has voids 4a. Details of the intermediate layer 4 including the voids 4a will be described later.

[0030] A sealing material 9 different from the solid electrolyte layer 6 may be positioned on the side surfaces of the intermediate layer 4 and the element portion 3. The material of the sealing material 9 may be dense glass or ceramic. The material of the sealing material 9 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 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 A -MgO-based material may be used. The sealant 9 may have electrical insulation properties. The sealant 9 may be located apart from the air electrode 8 or may be in contact with the air electrode 8. The material of the sealant 9 may be the same as the material of the solid electrolyte layer 6.

[0031] The cell 1 may further include a diffusion layer (not shown). The diffusion layer may be located between the anode 5 and the intermediate layer 4. The diffusion layer is gas permeable and allows the fuel gas flowing through the flow path 24 (see FIG. 1A ) to pass through to the anode 5. The open porosity of the diffusion layer may be, for example, 30% or more and 50% or less, particularly 35% or more and 45% or less.

[0032] The material of the 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, for example, a plurality of rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb. The material of the diffusion layer may also contain a rare earth element oxide that is not solid-solved in the stabilized zirconia.

[0033] The material of the diffusion layer, for example, reduces the shrinkage of the anode 5 during firing. This allows the degree of shrinkage of the anode 5 and the solid electrolyte layer 6 during firing to be similar, and therefore, in the cell 1 having the diffusion layer, warping or deformation of the element portion 3 is reduced.

[0034] Furthermore, the material of the diffusion layer is similar to the material of the anode 5, and the temperature at which the material of the diffusion layer begins to shrink is close to that of the material of the anode 5. On the other hand, the rare earth element oxide inhibits densification of the diffusion layer. As a result, the diffusion layer has appropriate gas permeability while making the element section 3 less susceptible to deformation. Therefore, the cell 1 having the diffusion layer has improved adhesion between the element section 3 and the intermediate layer 4, and improved durability.

[0035] The cell 1 may further include a constraining layer (not shown). The constraining layer may be located between the element portion 3 and the metal plate 32. The constraining layer cooperates with the solid electrolyte layer 6 to make the element portion 3 less susceptible to warping, bending, and the like.

[0036] 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.

[0037] 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.

[0038] The metal plate 32 has a first surface 321 and a second surface 322 located at both ends in the thickness direction, i.e., the Y-axis direction.

[0039] The metal plate 32 is electrically conductive. The metal plate 32 may be, for example, a member made of a metal containing chromium. The metal plate 32 may be, for example, a stainless steel such as a ferritic stainless steel or an austenitic stainless steel, which has high heat resistance. The metal plate 32 may be, for example, a nickel-chromium alloy or an iron-chromium alloy. The metal plate 32 may contain, for example, a metal oxide. The metal plate 32 may have a coating covering the surface. The metal plate 32 does not have to have a coating on the surface.

[0040] The metal plate 32 also has an opening 32a. The opening 32a is a through-hole that penetrates between the first surface 321 and the second surface 322. The fuel gas flowing through a flow path 33 (described later) is supplied to the fuel electrode 5 of the element section 3 through the opening 32a. The diameter of the opening 32a may be, for example, 0.1 mm or more and 0.5 mm or less, particularly 0.3 mm or more and 0.4 mm or less. When viewed in a plan view along the Y-axis direction, the aperture ratio of the region of the metal plate 32 where the opening 32a is formed may be, for example, 10% or more. The metal plate 32 may have a coating that covers the wall surface of the opening 32a. The metal plate 32 does not need to have a coating on the wall surface of the opening 32a.

[0041] The metal plate 32 may be gas permeable, for example. In such a case, the metal plate 32 does not need to have the opening 32a.

[0042] The cell 1 may further include a flow path member 34 and a current collecting member 36. The flow path member 34 is located on the second surface 322 side of the metal plate 32. The flow path member 34 is fixed and electrically joined, for example, at a contact portion with the second surface 322 by welding or the like. The flow path member 34 may be fixed and electrically joined to the metal plate 32 by a conductive sealing material, brazing material, or the like. The space located between the metal plate 32 and the flow path member 34 is a flow path 33 through which the fuel gas flows. The fuel gas flowing through the flow path 33 permeates the metal plate 32 and is supplied to the anode 5. The metal plate 32 may have one or more protrusions protruding toward the flow path member 34.

[0043] The flow path member 34 is further fixed and electrically joined to the current collecting member 36 by welding or the like. The current collecting member 36 may be fixed and electrically joined to the flow path member 34 by a conductive sealing material, brazing material, or the like. The current collecting member 36 may be 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 36 and the flow path member 34 is a flow path 35 through which an oxygen-containing gas flows. The oxygen-containing gas flowing through the flow path 35 passes through the adhesive from the slits in the current collecting member 36 and is supplied to the air electrode 8 of the adjacent cell 1.

[0044] The flow path member 34 and the current collecting member 36 may be made of a dense metal or alloy. The flow path member 34 makes it difficult for the fuel gas flowing through the flow path 33 and the oxygen-containing gas flowing through the flow path 35 to leak. The flow path member 34 and the current collecting member 36 may have a coating. For example, the surface of the flow path member 34 facing the flow path 33 may have a coating that is resistant to reduction. Furthermore, the surface of the flow path member 34 facing the flow path 35 may have a coating that is resistant to oxidation. These coating layers may be electrically conductive.

[0045] <Details of Voids and Intermediate Layer> Next, details of the voids 4a and the intermediate layer having the voids 4a will be further described with reference to FIGS. 1A, 1B and 2. FIG.

[0046] 2 is a plan view of an example of an electrochemical cell according to an embodiment, viewed from the element portion side. The cell 1 includes a metal plate 32, an element portion 3, and an intermediate layer 4. Note that in FIG. 2, components of the element portion 3, such as the air electrode 8, are not shown, and only an outline 30 of the element portion 3 viewed from the air electrode 8 side is shown.

[0047] 2, the contour 30 of the element portion 3 may have sides 3a to 3d and corners 3e to 3h. Side 3a is located at one end of the element portion 3 located on the negative side of the X-axis, and extends along the Z-axis direction intersecting the X-axis. Side 3c is located at the other end of the element portion 3 located on the positive side of the X-axis, and extends along the Z-axis. Side 3b is located at one end of the element portion 3 located on the negative side of the Z-axis, and extends along the X-axis direction intersecting the Z-axis. Side 3d is located at the other end of the element portion 3 located on the positive side of the Z-axis, and extends along the X-axis direction.

[0048] Corner 3e is located between side 3a and side 3b. Corner 3f is located between side 3b and side 3c. Corner 3g is located between side 3c and side 3d. Corner 3h is located between side 3d and side 3a.

[0049] 1B, the element unit 3 is located on a metal plate 32. The intermediate layer 4 is located between a first surface 321 of the metal plate 32 and the anode 5 of the element unit 3.

[0050] When the cell 1 is viewed in plan from the cathode 8 side of the element unit 3, the intermediate layer 4 has a void 4a that overlaps with at least a part of the outline 30 of the element unit 3. For example, as shown in FIG. 2 , when the cell 1 is viewed in plan from the cathode 8 side of the element unit 3 (i.e., in the Y-axis direction), the intermediate layer 4 may have a void 4a that overlaps with a side portion 3a of the outline 30 of the element unit 3. This makes it possible to alleviate stress caused by the difference in thermal expansion between the intermediate layer 4 and the metal plate 32 by the void 4a. This makes it less likely for cracks to occur in the intermediate layer 4, thereby improving the durability of the cell 1.

[0051] Furthermore, when the cell 1 is viewed in plan from the air electrode 8 side (i.e., in the Y-axis direction), the void 4a may be located between the outline 30 of the element portion 3 and the outline 40 of the intermediate layer 4. This can alleviate stress caused by the difference in thermal expansion between the intermediate layer 4 and the metal plate 32, making it less likely for cracks to occur in the intermediate layer 4. This improves the durability of the cell 1.

[0052] The intermediate layer 4 may also have a first portion 41 located outside the contour 30 of the element portion 3, with a gap 4a in between. This can further reduce stress caused by the difference in thermal expansion between the intermediate layer 4 and the metal plate 32, making it even less likely for cracks to occur in the intermediate layer 4. This improves the durability of the cell 1.

[0053] Furthermore, the voids 4a may have a length of 10 μm or more in a first direction perpendicular to the contour 30 of the element unit 3. For example, as shown in FIG. 2, when the cell 1 is viewed in plan from the cathode 8 side of the element unit 3 (i.e., the Y-axis direction), a case will be described in which the voids 4a overlap with the side portions 3a of the contour 30 of the element unit 3. In such a case, the direction perpendicular to the direction in which the side portions 3a extend (i.e., the Z-axis direction) (i.e., the X-axis direction) can be defined as the first direction. In this case, as shown in FIG. 1B, if the length of the voids 4a in the first direction is L1, L1 may be 10 μm or more. This facilitates relaxation of stress caused by the difference in thermal expansion between the intermediate layer 4 and the metal plate 32, making it less likely for cracks to occur in the intermediate layer 4. This improves the durability of the cell 1.

[0054] Furthermore, the void 4a may have a length of 500 μm or less in the first direction. For example, as shown in FIG. 1B , when the cell 1 is viewed in plan from the cathode 8 side of the element unit 3 (i.e., the Y-axis direction), the void 4a that overlaps with the side portion 3a of the outline 30 of the element unit 3 may have a length L1 of 500 μm or less. This firmly bonds the element unit 3 and the intermediate layer 4, improving the durability of the cell 1.

[0055] Furthermore, the void 4a may have a length of 15 μm or more and 50 mm or less in a direction along the contour 30 of the element unit 3. For example, as shown in FIG. 1B , when the cell 1 is viewed in plan from the air electrode 8 side of the element unit 3 (i.e., the Y-axis direction), if the length along the Z-axis direction of the void 4a that overlaps with the side portion 3a of the contour 30 of the element unit 3 is L2, L2 may be 15 μm or more and 50 mm or less.

[0056] 1B , when the thickness of the intermediate layer 4 along the thickness direction of the cell 1 (i.e., the Y-axis direction) is T0 and the length of the void 4a along the thickness direction of the intermediate layer 4 is L0, the ratio of L0 to T0, L0 / T0, may be 0.1 or more. This makes it easier to alleviate stress caused by the difference in thermal expansion between the element portion 3 and the metal plate 32, and improves the durability of the cell 1.

[0057] Furthermore, L0 / T0 may be 0.7 or less, which allows the element portion 3 and the intermediate layer 4 to be firmly bonded together, improving the durability of the cell 1.

[0058] Furthermore, when the cell 1 is viewed in plan from the air electrode 8 side of the element unit 3 (i.e., in the Y-axis direction), the voids 4a may be positioned so as to overlap with the sides 3a to 3d. This further reduces stress caused by the difference in thermal expansion between the intermediate layer 4 and the metal plate 32, making it even less likely for cracks to occur in the intermediate layer 4, compared to when the voids 4a are positioned so as to overlap only with the corners 3e to 3h of the outline 30 of the element unit 3. This improves the durability of the cell 1.

[0059] 1A , the shapes of the flow path member 34 and the current collecting member 36 of the cell 1 are not limited to those shown in Fig. 1A. The flow path member 34 and the current collecting member 36 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.

[0060] 3 is a cross-sectional view showing another example of an electrochemical cell according to an embodiment. As shown in FIG. 3, for example, a flow path member 34 may be integrated with a current collecting member 36 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.

[0061] Next, another example of the cell 1 according to the embodiment will be described with reference to Figures 4A to 4F. Figures 4A to 4F are cross-sectional views showing another example of the electrochemical cell according to the embodiment. Note that Figures 4A to 4F correspond to partially enlarged cross-sections of the cell 1 shown in Figure 1B or Figure 3.

[0062] 4A, the length of the voids 4a in the width direction (i.e., the X-axis direction) intersecting the thickness direction (i.e., the Y-axis direction) of the intermediate layer 4 may be greater than the length in the thickness direction (i.e., the Y-axis direction) of the intermediate layer 4. Also, as shown in FIG. 4B, the length of the voids 4a in the width direction (i.e., the X-axis direction) intersecting the thickness direction (i.e., the Y-axis direction) of the intermediate layer 4 may be smaller than the length in the thickness direction (i.e., the Y-axis direction) of the intermediate layer 4.

[0063] 4C , the cross-sectional shape of the gap 4 a along the first direction may be asymmetric with respect to the YZ plane perpendicular to the XY plane. The cross-sectional shape of the gap 4 a along the first direction may be symmetric with respect to any plane and / or line perpendicular to the XY plane. The cross-sectional shape of the gap 4 a along the first direction may be asymmetric with respect to any plane and / or line perpendicular to the XY plane.

[0064] 4D, the cross-sectional shape of the void 4a along the first direction may be circular or approximately circular. Also, as shown in Fig. 4E, the void 4a may be formed so that the length in the first direction decreases with increasing distance from the anode 5. Also, as shown in Fig. 4F, the void 4a may be located inside the intermediate layer 4, away from the first surface 321 of the metal plate 32 and the anode 5.

[0065] Furthermore, the void 4 a may have an opening facing the first surface 321 of the metal plate 32 and / or the anode 5. Compared to a void 4 a without an opening, the void 4 a with such an opening can further relieve stress caused by the difference in thermal expansion between the intermediate layer 4 and the metal plate 32, making it even less likely for cracks to occur in the intermediate layer 4. This further improves the durability of the cell 1.

[0066] Here, the arrangement and shape of the voids 4a, the values ​​of T0, L0, and L1 shown in FIG. 1B, and the values ​​of L2 shown in FIG. 2 can be obtained as follows. For example, a polished cross section of the cell 1 including the anode 5, the intermediate layer 4, and the metal plate 32 can be measured by image analysis of a backscattered electron image using a SEM (scanning electron microscope) or a TEM (transmission electron microscope). Specifically, the cell 1 is scanned and analyzed using X-ray CT (computed tomography) to identify the position of the voids 4a. From the X-ray CT image including the voids 4a, the T0, L0, L1, and L2 of the voids 4a can be measured. Alternatively, a cross section of the cell 1 (see, for example, FIG. 1B) that includes the identified voids 4a and is perpendicular to the outline 30 of the element portion 3 where the voids 4a are located may be polished, and the T0, L0, and L1 of the voids 4a may be measured by image analysis of a backscattered electron image of the cross section using a SEM or a TEM. Alternatively, the cross section of the cell 1 along the contour 30 of the element portion 3 may be polished, and the T0, L0 and L2 of the gap 4a may be measured by image analysis of a backscattered electron image of the cross section using an SEM or TEM.

[0067] <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. 5A to 5C. Fig. 5A is a perspective view showing an example of an electrochemical cell device according to an embodiment. Fig. 5B is a cross-sectional view taken along line XX shown in Fig. 5A. Fig. 5C is a top view showing an example of an electrochemical cell device according to an embodiment.

[0068] As shown in Figure 5A, the cell stack device 10 comprises a cell stack 11 having multiple cells 1 arranged (stacked) in the thickness direction of the cells 1 (i.e., the Y-axis direction shown in Figure 1A), and a fixing member 12.

[0069] 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 member 14, which includes the support 15 and the gas tank 16, may be made of metal. The support member 14, which includes the support 15 and the gas tank 16, may be electrically conductive.

[0070] 5B, 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.

[0071] 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.

[0072] In the example shown in Fig. 5A, fuel gas is stored in an internal space 22 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 33 (see Fig. 1A) inside the cell 1. The fuel gas supplied to the gas tank 16 is generated in a reformer 102 (see Fig. 6), which will be described later. The internal space 22 may also be referred to as a space containing fuel gas and having a reducing atmosphere.

[0073] 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.

[0074] The example shown in Fig. 5A 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 may have two through-holes on the top surface. A support 15 is disposed in each through-hole. The internal space 22 may be formed by one gas tank 16 and two supports 15.

[0075] 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 ).

[0076] 5B , the joint between the inner wall of the insertion hole 15a and the lower end of the cell 1 is filled with a fixing material 13 and solidified. As a result, the inner wall of the insertion hole 15a and the lower end of each of the cells 1 may be joined and fixed. Alternatively, the lower ends of the cells 1 may be joined and fixed to each other. The gas flow path 2a of each cell 1 may communicate with the internal space 22 of the support member 14 at its lower end.

[0077] 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.

[0078] 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.

[0079] 5B , a conductive member 18 may be interposed between adjacent cells 1 among the plurality of cells 1. The conductive member 18 can electrically connect one adjacent cell 1 to the other adjacent cell 1 in series. More specifically, the conductive member 18 may connect 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 flow path member 34 or the current collecting member 36 shown in FIG. 1A , or may be a member separate from the flow path member 34 and the current collecting member 36.

[0080] 5B, an end current collecting member 17 may be electrically connected to the cell 1 located at the outermost position in the arrangement direction of the multiple cells 1. The end current collecting member 17 may be connected to a conductive portion 19 that protrudes to the outside of 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. 5A.

[0081] 5C, the cell stack device 10 has two cell stacks 11A and 11B connected in series to function as a single battery. Therefore, the conductive portion 19 of the cell stack device 10 is divided into a positive terminal 19A, a negative terminal 19B, and a connection terminal 19C.

[0082] 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.

[0083] 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.

[0084] <Module> Next, a module according to this embodiment using the above-described cell stack device 10 will be described with reference to Fig. 6. Fig. 6 is an external perspective view showing an example of a module according to this embodiment. Fig. 6 shows a state in which the front and rear surfaces, which are part of the storage container 101, have been removed and the cell stack device 10 of the fuel cell stored inside has been taken out to the rear.

[0085] 6, 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.

[0086] 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.

[0087] The fuel gas produced in the reformer 102 is supplied to the flow path 33 of the cell 1 (see FIG. 1A) through the gas distribution pipe 20, the gas tank 16, and the support member 14.

[0088] Furthermore, in the module 100 having the above-described configuration, the temperature inside the module 100 during normal power generation is approximately 500° C. or higher and 1000° C. or lower due to the combustion of gas and the power generation of the cells 1 .

[0089] In such a module 100, as described above, the module 100 is configured by accommodating the cell stack device 10 having a plurality of highly durable cells 1, thereby making it possible to make the module 100 highly durable.

[0090] <Module Enclosure Device> Fig. 7 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. 6, 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. 7.

[0091] An exterior case 111 of a module accommodating device 110 shown in Figure 7 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 Figure 7, 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, highly durable modules 100 are provided in the module accommodating chamber 115, so that the module accommodating device 110 can be made highly durable.

[0094] [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.

[0095] 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.

[0096] In one embodiment, (1) an electrochemical cell includes: a metal plate having a first surface and a second surface located opposite the first surface; an element portion having a first electrode facing the first surface, a solid electrolyte layer, and a second electrode located opposite the first electrode with the solid electrolyte layer sandwiched therebetween; and an intermediate layer located between the first surface and the first electrode, wherein the intermediate layer has a gap that overlaps with at least a portion of the outline of the element portion when viewed in plan from the second electrode side.

[0097] (2) In the electrochemical cell of (1) above, when viewed from above from the second electrode side, the void may be located between the contour and a contour of the intermediate layer.

[0098] (3) In the electrochemical cell of (1) or (2) above, the intermediate layer may have a first portion located outside the outline of the element portion across the gap.

[0099] (4) In the electrochemical cell of any one of (1) to (3) above, the void may have a length of 10 μm or more in a first direction perpendicular to the outline of the element portion.

[0100] (5) In the electrochemical cell of (4) above, the void may have a length of 500 μm or less in the first direction.

[0101] (6) In the electrochemical cell of any one of (1) to (5) above, when the thickness of the intermediate layer is T0 and the length of the void along the thickness direction of the intermediate layer is L0, L0 / T0 may be 0.1 or more.

[0102] (7) In the electrochemical cell of (6) above, the L0 / T0 may be 0.7 or less.

[0103] (8) In the electrochemical cell of any one of (1) to (7) above, the contour of the element portion may have sides and corners, and when viewed in a plan view from the second electrode side, the void may overlap the sides.

[0104] In one embodiment, (9) an electrochemical cell device has a cell stack including any one of the electrochemical cells (1) to (8) above.

[0105] In one embodiment, a module (10) includes the electrochemical cell device (9) described above, and a container for housing the electrochemical cell device.

[0106] In one embodiment, (11) a module housing device includes: the module of (10); an auxiliary device for operating the module; and an exterior case for 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 portion 4 intermediate layer 4a gap 5 fuel electrode 6 solid electrolyte layer 8 air electrode 9 sealing material 10 cell stack device 30 (element portion) outline 32 metal plate 40 (intermediate layer) outline 41 first portion 100 module 110 module housing device

Claims

1. An electrochemical cell comprising: a metal plate having a first surface and a second surface located opposite the first surface; an element portion having a first electrode facing the first surface, a solid electrolyte layer, and a second electrode located on the opposite side of the solid electrolyte layer from the first electrode; and an intermediate layer located between the first surface and the first electrode, wherein the intermediate layer has a gap that overlaps at least a portion of the outline of the element portion when viewed in plan from the second electrode side.

2. The electrochemical cell according to claim 1, wherein, when viewed from above from the second electrode side, the gap is located between the contour and the contour of the intermediate layer.

3. The electrochemical cell according to claim 1 or 2, wherein the intermediate layer has a first portion positioned outside the outline of the element portion across the gap.

4. An electrochemical cell according to any one of claims 1 to 3, wherein the gap has a length of 10 µm or more in a first direction perpendicular to the contour of the element portion.

5. The electrochemical cell according to claim 4, wherein the void has a length in the first direction of 500 μm or less.

6. The electrochemical cell according to any one of claims 1 to 5, wherein when the thickness of the intermediate layer is T0 and the length of the void along the thickness direction of the intermediate layer is L0, L0 / T0 is 0.1 or greater.

7. The electrochemical cell according to claim 6, wherein L0 / T0 is 0.7 or less.

8. An electrochemical cell according to any one of claims 1 to 7, wherein the contour of the element portion has sides and corners, and when viewed in a plan view from the second electrode side, the voids overlap with the sides.

9. An electrochemical cell device having a cell stack including the electrochemical cell according to any one of claims 1 to 8.

10. A module comprising the electrochemical cell device according to claim 9 and a container housing the electrochemical cell device.

11. A module housing device comprising: a module according to claim 10; an accessory configured to operate said module; and an outer case housing said module and said accessory.

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