JP2005019072A - Solid electrolyte fuel cell and unit cell for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a unit cell for a fuel cell having no gas leakage, wherein the unit cell is formed by laminating a cell element on an electrical conductive metal substrate, and to provide a light and thin solid electrolyte fuel cell without deteriorating performance by laminating the unit cell having no gas leakage. <P>SOLUTION: A unit cell for fuel cell 1 is formed by comprising an electrical conductive metal substrate 2 with a though-hole 2a and a cell element 3 formed so as to hold an electrolyte layer 3c between a fuel electrode layer 3a and an air electrode layer 3b and by laminating the element 3 to the through-hole 2a of the substrate 2. A sealing member 4 is impregnated between the substrate 2 of the unit cell 1 and the end of the fuel electrode layer 3a of the elements 3 contacting to the substrate 2 so as to cover the through-hole 2a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid electrolyte fuel cell having a configuration in which a solid electrolyte is sandwiched between a pair of electrodes as a battery element, and a single cell for a fuel cell.
[0002]
[Prior art]
Conventional solid oxide fuel cells include a cell, a cell support, and a separator, and a cell enclosure that covers the cell is formed by joining the outer periphery of each of the cell support and the separator. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-45454
[Problems to be solved by the invention]
However, in the above-described solid oxide fuel cell, the outer periphery of each of the cell support and the separator forming the cell enclosure is joined in a state where airtightness is ensured, but the cell and the cell support Since there is no gas seal between them, there is a risk that the gas may cross-leak, and as a result, there is a problem that the performance may be deteriorated, and it is a conventional problem to solve this problem It was.
[0005]
OBJECT OF THE INVENTION
The present invention has been made by paying attention to the above-described conventional problems, and provides a single cell for a fuel cell free from gas leakage, which is formed by laminating battery elements on an electrically conductive metal substrate, and a fuel cell free from this gas leakage. It is an object of the present invention to provide a lightweight and thin solid oxide fuel cell that does not cause a decrease in performance by stacking single cells for use.
[0006]
[Means for Solving the Problems]
The solid electrolyte fuel cell according to the present invention includes an electrically conductive metal substrate having a through hole and a battery element formed by sandwiching an electrolyte layer between a pair of electrode layers, and the above-described electrode is formed on the through hole of the electrically conductive metal substrate. In a solid oxide fuel cell having a single cell for a fuel cell formed by stacking battery elements, the electrically conductive metal substrate of the single cell for a fuel cell is in contact with the electrically conductive metal substrate so as to cover a through hole. It is characterized by having a structure in which a sealing material is impregnated between the end portions of the electrode layer of the battery element, and the structure of this solid oxide fuel cell is a means for solving the above-described conventional problems. .
[0007]
In the solid oxide fuel cell of the present invention, since the sealing material is impregnated between the electrically conductive metal substrate of the single cell for fuel cells and the end of the electrode layer of the battery element, the electrically conductive metal substrate and Gas leakage from between the battery elements is prevented, and by stacking the single cells for fuel cells without such gas leakage, the light weight and thickness can be reduced without degrading the performance.
[0008]
【The invention's effect】
According to the present invention, since it has the above-described configuration, it is possible to provide a very excellent effect that it is possible to provide a solid oxide fuel cell that is lightweight and thin, and hardly causes gas leakage.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the solid oxide fuel cell according to the present invention, a single cell for a fuel cell in which a thin-film battery element is laminated on an electrically conductive metal substrate having a through-hole has a peripheral portion made of a gastight electrically conductive metal substrate. For the convenience of disposing a porous electrode layer on the through-hole of the electrically conductive metal substrate, it is necessary to perform a gas seal around this electrode layer. Also, when an electrolyte layer thinner than 100 μm is formed immediately above the electrode layer covering the through-hole, cracks are likely to occur from the stepped portion due to the heat cycle, and a cross leak occurs and the performance deteriorates.
[0010]
Therefore, if the periphery of the electrode layer is covered with a sealing material so as to ensure airtightness, the strength of the end of the electrode layer is increased and gas cross-leakage can be prevented. At this time, since the peripheral portion of the unit cell for the fuel cell is an electrically conductive metal substrate, the end of the electrode layer may be sealed only on one side on which the battery elements are laminated, and thus only one side is sealed. Therefore, the stress is released without restraining the member, and problems such as breakage are reduced, and durability is improved.
[0011]
As a sealing material covering the periphery of the electrode layer, for example, a gas having a melting point equal to or higher than the operating temperature of glass, Ag, an Ag alloy, etc. is softened above the melting point and impregnated into the porous electrode layer. A material that shuts off is used.
[0012]
In the solid oxide fuel cell of the present invention, it is desirable to provide a cell support that is bonded to the electrically conductive metal substrate via a sealing material. By sticking the cell support through the sealing material covering the periphery of the electrode layer in this way, the outer peripheral portion of the single cell for the fuel cell is reinforced, and the cell support is performed without processing the single cell for the fuel cell. If only the body is processed, stacking is possible, and as a result, the peripheral members of the fuel cell single cell can be simplified.
[0013]
In addition, since the cell support is attached to only one side of the fuel cell unit cell, there is no need to press the outer periphery of the fuel cell unit cell from above and below for gas sealing. It can be stacked without any effort. That is, the fuel cell single cell can be processed without damaging it, and the processing itself can be simplified. In addition, it is desirable to use a 10-500 micrometers thin plate for a cell support body, and it is desirable that the distance of a cell support body and an electroconductive metal substrate shall be 0-5 mm.
[0014]
In the solid oxide fuel cell according to the present invention, the cell support has a plurality of openings, each of the openings is provided with a single cell for a fuel cell, and the periphery of the opening and the electric power of the single cell for the fuel cell are arranged. It is desirable to bond the conductive metal substrate to each other through a sealing material, so that a plurality of fuel cell single cells can be installed on the cell support, that is, the plurality of fuel cell single cells are the same. A so-called cell plate installed on a flat surface is obtained.
[0015]
Thus, if a plurality of single cells for a fuel cell are installed on the same plane, the thermal stress caused by the heat cycle can be relaxed. In addition, since the difference in heat generation temperature occurs in the cell surface due to the difference in fuel concentration generated between the gas upstream and gas downstream during power generation, the difference in heat generation temperature may occur when the area of a single cell for a fuel cell is large. However, as described above, the temperature difference is reduced by reducing the area of each single unit cell for fuel cells, reducing the thermal stress. Accordingly, it is possible to improve durability by providing the cell support.
[0016]
In the solid oxide fuel cell of the present invention, when the cell support is made of a conductive material and the insulating material is a sealing material, the sealing material can be electrically insulated when the battery elements are stacked. For this reason, the degree of freedom in design is expanded, and a compact design can be realized.
[0017]
In this case, as the conductive material constituting the cell support, a heat resistant alloy containing Ni, Ag, Pt, Cu such as SUS or Inconel can be adopted, and it is desirable to use a metal foil of 10 to 500 μm. . On the other hand, as the sealing material having an insulating property, an electrically insulating material such as glass or ceramic that softens at a melting point or higher and exhibits a gas sealing property is suitably used.
[0018]
On the other hand, if the cell support is made of an insulating material, the cell support can be electrically insulated when the battery elements are stacked, so that the degree of freedom in design is expanded as described above. Compacting is possible.
[0019]
In this case, as an insulating material constituting the cell support, an insulator (<10 ⁻⁷ S · cm ⁻¹ ) member such as ceramics such as Al ₂ O ₃ and TiO ₂ and glass such as SiO ₂ is used. Are preferably used. In addition, the cell support may have a frame shape or a shape having a plurality of openings.
[0020]
By configuring the cell support with an insulating material, both the insulating material and the conductive material can be used as the sealing material, and the degree of freedom of design is expanded accordingly. If silver or a silver alloy, which is a conductor, is used as a material, adjacent single cells can be electrically connected in parallel. On the other hand, if an insulating material is used as a sealing material, single cells can be electrically divided. It will be.
[0021]
In the solid oxide fuel cell of the present invention, when the fuel cell single cells are stacked on each other, that is, a plurality of fuel cell single cells are stacked, or a plurality of fuel cell single cells are installed on the same plane. When the cell plates are stacked, the structure of the joining portion is simplified, so that the weight of the parts can be reduced, and a thin and lightweight solid oxide fuel cell can be manufactured.
[0022]
【Example】
Hereinafter, the present invention will be described with reference to the drawings.
[0023]
[Example 1]
FIG. 1 shows an embodiment of the present invention.
[0024]
As shown in FIG. 1, this single cell 1 for fuel cells includes an electrically conductive metal substrate 2 having a through hole 2a and a battery element 3 formed by sandwiching an electrolyte layer 3c between a pair of electrode layers 3a and 3b. The battery element 3 is laminated on the through hole 2a of the electrically conductive metal substrate 2, and the electrically conductive metal substrate 2 is in contact with the electrically conductive metal substrate 2 so as to cover the through hole 2a. A sealing material 4 is impregnated between the ends of the electrode layer (fuel electrode) 3a of the battery element 3 to be operated.
[0025]
In this embodiment, the electrically conductive metal substrate 2 is an etching board made of SUS430 having a thickness of 0.1 mm manufactured by photoetching, and the fuel electrode layer 3a constituting the battery element 3 is manufactured by screen printing. 0.12 mm NiO + SDC (Sm-added ceria), electrolyte layer 3c 10ScSZ (Sc-added stabilized zirconia) produced by screen printing, and cathode layer 3b produced by screen printing SSC having a layer thickness of 20um (Sm, Sr-added cobalt oxide), and the sealing material 4 is a glass seal made of low-melting glass.
[0026]
Specifically, the fuel electrode layer 3a of the battery element 3 is formed by baking at 1100 ° C. in an H ₂ reducing atmosphere after applying the paste, and the electrolyte layer 3c is formed by reducing the H ₂ reduction after applying the paste. The air electrode layer 3b is formed by baking at 850 ° C. in an H ₂ reducing atmosphere after applying the paste. Further, the sealing material 4 is applied to the porous portion of the electrically conductive metal substrate 2 and then melted and impregnated while being kept at 800 ° C.
[0027]
In this single cell 1 for a fuel cell, since the periphery of the fuel electrode layer 3a of the battery element 3 is covered with a sealing material 4 so as to ensure airtightness, the strength of the end of the fuel electrode layer 3a is increased and gas cross In this case, since the peripheral portion of the unit cell 1 for the fuel cell is the electrically conductive metal substrate 2, the seal at the end of the fuel electrode layer 3a has at least the battery element 3 laminated. Since only one side (the upper surface in the figure) needs to be sealed, it is sufficient to seal only one side, so that stress is released without restraining the members, and problems such as breakage are reduced, resulting in improved durability. Will be.
[0028]
[Example 2]
FIG. 2 shows another embodiment of the present invention.
[0029]
As shown in FIG. 2, in the solid oxide fuel cell of this embodiment, a frame-shaped cell joined to the fuel cell single cell 1 of Embodiment 1 via an electrically conductive metal substrate 2 and a sealing material 4. A support 5 is provided, and the cell support 5 is a conductive substrate made of Inconel having a thickness of 50 μm. The configuration of the fuel cell single cell 1 itself is the same as that of the first embodiment.
[0030]
In the solid oxide fuel cell in this embodiment, the cell support 5 is attached via the sealing material 4 that covers the periphery of the fuel electrode layer 3a of the battery element 3, so that the single cell 1 for fuel cell 1 itself is processed. Stacking is possible by processing only the cell support 5 without the need, and as a result, the peripheral members of the unit cell 1 for fuel cells can be simplified. Further, in the solid oxide fuel cell according to this embodiment, the cell support 5 is made of a conductive substrate, and the glass seal made of low-melting glass is used as the sealing material 4. Since the material 4 can be electrically insulated, the degree of freedom in design is increased and a compact design can be realized.
[0031]
[Example 3]
FIG. 3 shows still another embodiment of the present invention.
[0032]
As shown in FIG. 3, in the solid oxide fuel cell in this example, in addition to the single cell 1 for the fuel cell of Example 1, a cell support 15 made of SUS430 having a plate thickness of 100 μm is provided.
[0033]
In this case, the cell support 15 has a disk shape having a plurality of openings 15a. The single cell 1 for the fuel cell of Example 1 is disposed in each of the openings 15a, and the openings 15a The peripheral edge portion and the electrically conductive metal substrate 2 of the unit cell 1 for a fuel cell are joined via a sealing material 4.
[0034]
In the solid oxide fuel cell in this embodiment, by using the cell support 15 having a plurality of openings 15a, a so-called cell plate 1A in which a plurality of fuel cell single cells 1 are installed on the same plane is obtained. As described above, if a plurality of single cells 1 for a fuel cell are installed on the same plane, thermal stress generated by the heat cycle can be alleviated, and improvement in durability can be realized.
[0035]
[Example 4]
FIG. 4 shows still another embodiment of the present invention.
[0036]
As shown in FIG. 4, in the solid oxide fuel cell according to this example, the single cell 1 for the fuel cell of Example 1 is provided with an insulating cell support 25 made of Al ₂ O ₃ having a thickness of 100 μm. ing.
[0037]
The cell support 25 has a frame shape having a plurality of openings 25a. The single cell 1 for the fuel cell of Example 1 is disposed in each of the openings 25a, and the periphery of the opening 25a The electrically conductive metal substrate 2 of the unit cell 1 for a fuel cell is joined via a sealing material 4.
[0038]
In this case, as shown in FIG. 4B, the sealing material 4A for joining the vertical frame 25b and the horizontal frame 25c passing through the center of the cell support 25 to the electrically conductive metal substrate 2 is a conductive material made of a silver alloy. As a seal.
[0039]
Also in the solid oxide fuel cell in this embodiment, since a cell plate in which a plurality of single cells 1 for fuel cells are installed on the same plane is obtained, the thermal stress caused by the heat cycle can be alleviated, and durability is improved. An improvement in performance can be realized.
[0040]
In this embodiment, since the cell support 25 is made of Al ₂ O ₃ , the cell support 25 can be electrically insulated when the battery elements 3 are stacked. Therefore, it is possible to achieve a compact size.
[0041]
Thus, by constituting the cell support 25 with Al ₂ O ₃ which is an insulating material, both the insulating sealing material 4 and the conductive sealing material 4A can be used. The degree of freedom is widened, and by using the conductive sealing material 4A made of a silver alloy as in this embodiment, adjacent fuel cell single cells 1 can be electrically connected in parallel. In addition, if the insulating sealing material 4 is used also for the joint part of the vertical frame 25b and the horizontal frame 25c which pass through the center of the cell support body 25, the single cells 1 for fuel cells can be electrically divided.
[0042]
[Example 5]
FIG. 5 shows still another embodiment of the present invention.
[0043]
As shown in FIG. 5, the solid oxide fuel cell in this example includes a cell plate 1A in a plurality of examples 3 and a plurality of separators 6 each having a flow path formed on a conductive substrate made of Inconel having a thickness of 150 μm. In this solid oxide fuel cell, the structure of the joint is simplified, so the weight of the parts is reduced, and a thin and lightweight solid oxide fuel cell is manufactured. Will get.
[0044]
In addition, the code | symbol 7 in FIG. 5 shows a porous conductor, the code | symbol 8 has shown the fuel flow, and the code | symbol 9 has shown the air flow, respectively.
[0045]
The detailed configurations of the solid oxide fuel cell and the single cell for fuel cell of the present invention are not limited to the above-described embodiments.
[Brief description of the drawings]
FIG. 1 is an explanatory cross-sectional view showing one embodiment of a solid oxide fuel cell of the present invention.
FIG. 2 is an explanatory plan view (a) and a sectional explanatory view (b) showing another embodiment of the solid oxide fuel cell of the present invention.
FIG. 3 is an explanatory plan view (a) and a sectional explanatory view (b) showing still another embodiment of the solid oxide fuel cell of the present invention.
FIG. 4 is an explanatory plan view (a) and an explanatory sectional view (b) showing still another embodiment of the solid oxide fuel cell of the present invention.
FIG. 5 is a cross-sectional explanatory view showing still another embodiment of the solid oxide fuel cell of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Unit cell for fuel cells 2 Electrically conductive metal substrate 2a Through-hole 3 Battery element 3a Fuel electrode layer (electrode layer)
3b Air electrode layer (electrode layer)
3c Electrolyte layer 4 Insulating sealing material 4A Conductive sealing material 5, 15, 25 Cell support

Claims (7)

A fuel cell comprising a conductive metal substrate having a through hole and a battery element formed by sandwiching an electrolyte layer between a pair of electrode layers, and the battery element is laminated on the through hole of the conductive metal substrate. In a solid oxide fuel cell including a single cell, an electric conductive metal substrate of the single cell for the fuel cell, and an end portion of an electrode layer of a battery element in contact with the electric conductive metal substrate so as to cover a through hole A solid oxide fuel cell, wherein a sealing material is impregnated in between. The solid oxide fuel cell according to claim 1, further comprising a cell support that is joined to the electrically conductive metal substrate via a sealing material. The cell support includes a plurality of openings, each of which is provided with a single cell for a fuel cell, and the periphery of the opening and the electrically conductive metal substrate of the single cell for a fuel cell are interposed via a sealing material. The solid oxide fuel cell according to claim 2, which is bonded to each other. The solid oxide fuel cell according to claim 2 or 3, wherein the cell support is made of a conductive material, and the sealing material has an insulating property. 4. The solid oxide fuel cell according to claim 2, wherein the cell support is made of an insulating material. The solid oxide fuel cell according to any one of claims 1 to 5, wherein a plurality of single cells for a fuel cell are stacked on each other. A fuel cell comprising a conductive metal substrate having a through hole and a battery element formed by sandwiching an electrolyte layer between a pair of electrode layers, and the battery element is laminated on the through hole of the conductive metal substrate. In a single cell, a sealing material is impregnated between the electrically conductive metal substrate and an end portion of an electrode layer of a battery element that contacts the electrically conductive metal substrate so as to cover a through hole. Single cell for fuel cell.

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