JPH03257760A - Solid electrolyte type fuel cell - Google Patents

Abstract

PURPOSE:To improve the gas sealing property of the inner manifold part, and to secure an optimum contact for electric conduction by forming a cell three- layer membrane only at the central part of a separator, carrying out the gas sealing at the periphery of the three-layer membrane with seal plates, and separating the inner manifold part from the cell three-layer membrane spatially. CONSTITUTION:Numerous projections are formed on the surface of a separator 9, manifolds 17 to deliver or exhaust the air and the fuel are provided at the outer periphery of them, and cell three-layer membrane 15 which consist of a fuel electrode, a solid electrolyte, and an air electrode are formed on the surface of porous conductive membranous bases 18. The cell three-layer membranes 15 are formed only at the center of the separator 9, and a distance is placed from the inner manifolds 17. And a cell main body made by forming the cell three-layer membrane 15 on the base 18, a seal plate 19 connected to the outer periphery of the cell main body maintaining gas tightness, and a separator 9 are laminated each other, so as to seal between the cell three-layer membranes 15, and the seal plates 19 and the bases 18. Consequently, the gas sealing property at the inner manifold 17 part is improved, and a good contact for electric conduction can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid oxide fuel cell, and particularly to a seal structure thereof.

[Prior Art] Recently, fuel cells have attracted attention and have been developed as a device that directly converts free energy changes in chemical reactions into electrical energy.

A fuel cell is different from a normal chemical cell, but the difference is that the active material of the electrode is not contained within the battery container, the negative electrode contains fuel, and the positive electrode contains a substance that oxidizes the fuel. It generates electricity by continuously supplying energy, and commercialization is being actively considered as one of the leading direct power generation systems.

Among these fuel cells, solid electrolyte fuel cells using stabilized zirconia as an electrolyte are attracting attention as third generation fuel cells.

A solid oxide fuel cell is configured to include a large number of electrode members each having an electrode portion formed thereon, and to electrically connect these electrode members.

FIG. 4 is an explanatory diagram of the principle of such a fuel cell.

As shown in FIG. 4, a solid electrolyte 1, such as stabilized zirconia, is provided with an air electrode 2 on one surface and a fuel electrode 3 on the other surface.

When air (0□) flows through the air electrode 2 and fuel gas (H, Co) flows through the fuel electrode 3, the reaction 02 + 4 e→20 occurs on the air electrode 2 side, and on the fuel electrode 3 side, The reaction 20 →02+4e occurs.

The electrons (e) generated by the above reaction are transferred to the fuel electrode 3
It moves from the side toward the air electrode 2, and electricity flows between the air electrode 2 and the fuel electrode 3.

H+11202→H20 During this reaction, water generated at the same time is discharged from the system.

The solid electrolyte fuel cell is constructed as described above, but as shown in FIG. The electrode member 4 has an electrode 2 formed thereon and a fuel electrode 3 formed on the other side.The electrode member 4 is made of a metal foam, ceramic felt, ceramic foam, etc. that has gas permeability, conductivity, atmosphere resistance, and cushioning properties. distributor 5
A large number of interconnectors 6 are arranged such that the distributor 5 is pressed against the outside of the distributor 5, and a large number of interconnectors 6 are stacked as one unit. Then, the outermost ink connectors 6 are connected to form an electric circuit, and the space formed by the air electrode 2 of the electrode section 4 and the interconnector 6 is gas-sealed with an O-ring 7 to form a fuel passage. , respectively, to supply air and fuel.

However, the conventional flat plate type solid electrolyte fuel cell as described above has a problem in that a gas seal is always required between each electrode member and the interconnector.

Therefore, as a means to solve this problem, the present inventors proposed the following electrode member for a solid oxide fuel cell in Utility Model Application No. 142253/1983.

That is, a solid metal plate separator having a large number of concave portions on at least one surface except for the periphery, has a three-layer film consisting of a fuel electrode, a solid electrolyte, and an air electrode formed on one surface of the four parts. An electrode member for an electrolyte fuel cell is an electrode member for a solid oxide fuel cell in which the peripheral portion of the electrode that contacts a metal flat plate separator is sealed with a solid electrolyte.

To explain this electrode member with reference to FIG. 6, a fuel electrode 3, a solid electrolyte 1, an air electrode 2, The films are formed in this order or in the reverse order.

As shown in the perspective view of Fig. 7, a solid oxide fuel cell using this electrode member has electrode members stacked in multiple stages (three stages in the case of Fig. 7) with spacers IO interposed therebetween. . The separator 9 and the spacer 10 are formed with passages 11 and 12 that serve as fuel passages or air passages, and the fuel is supplied through the passages 11 and 12 via the groove 8 of the separator 9. It has become. Further, the spacer 10 is provided with a fuel or air supply hole 13 and a discharge hole 14 so that fuel or air is supplied to the electrode 2 or 3 that is in contact with the lower surface of the seven filters 9. Therefore, this solid oxide fuel cell does not require a special gas seal.

However, in the solid electrolyte fuel cell described above, the metal separator and the electrode in contact with the metal separator have significantly different components, so there is a difference in thermal expansion between the two. The three-layer body consisting of is easily destroyed.

Furthermore, some metals have a small difference in thermal expansion from ceramics and ceramics, which are the materials of the electrodes, but metals are limited due to problems such as poor high temperature resistance.

[Problem to be solved by the invention] In the above flat plate solid electrolyte fuel cells, air.

One of the remaining issues is the gas seal for fuel, etc.
Until now, there has been no effective method for this.

1) In a flat plate type solid electrolyte fuel cell, as shown in FIG. It is necessary to prevent leakage of air or fuel, but with the method of sandwiching and pressing the battery three-layer membrane 15 with the separator 9, since the battery three-layer membrane 15 is a thin ceramic film, the battery may be damaged and the seal may be broken. Since this is not possible, it is necessary to seal the four peripheries of the battery.

2) In order to avoid the above problem, as shown in FIG.
The method of fixing the separator 9 and the battery 3-layer membrane 15 is often carried out in the laboratory, but for large batteries, the separator 9 and the battery 3-layer membrane 15
There is a risk that the adhesive portion 16 or the battery three-layer membrane 15 may be damaged due to the difference in thermal expansion.

At present, there are 16 effective adhesives that can withstand temperatures of 1000°C.
It is not reliable. Therefore, it has been desired to improve the reliability of the adhesive and absorb the difference in thermal expansion.

3) In addition, in order to supply fuel and air to each cell part, an internal manifold method is preferable to the method of piping to each cell, as shown in Figure 8(C), but in this case,
It is also necessary to prevent leakage of air and fuel at the laminated portions of the separator 9 and spacer 10.

A possible method for sealing the manifold 17 part is to clamp ceramic paper between this part as a gasket. There is a need to.

Furthermore, if the distance between the battery three-layer film 15 and the separator 9 is too large, the battery will not conduct electricity and will no longer function as a battery.

Therefore, there is a need for sealing of the internal manifold 17, as well as a need for energizing contacts.

The present invention provides: ■Sealing of the four circumferential parts of the battery's three-layer membrane; ■Sealing of the internal manifold; ■Separator and battery contact for energization; ■Preventing the cell from being damaged by excessive pressing force; ■Separator and cell The aim is to solve five problems at the same time, such as escaping the difference in thermal expansion.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides the following: (1) An internal manifold for supplying and recovering fuel and air is provided on the outer periphery of the separator.

■The battery 3-layer membrane should be placed only in the center of the separator, keeping a distance from the internal manifold.

■The separator shall have a thin plate structure.

(2) A seal plate is provided on the outer periphery of the three-layer battery membrane to seal the outer circumference of the three-layer battery membrane.

■Put the outer periphery of the seal plate between the separators,
Forms part of the internal manifold.

■The seal plate and the outer periphery of the three-layer battery membrane are made gas-tight by filling them with a gas-tight material.

This is a solid oxide fuel cell having the above configuration.

That is, the present invention provides a battery body in which a three-layer battery film consisting of a fuel electrode, a solid electrolyte, and an air electrode is formed on a conductive and gas-permeable substrate, and a gas-tightness in the outer periphery of the battery. The battery 3
A solid oxide fuel cell, which seals between the layer membrane, the seal plate, and the substrate, and is equipped with an internal manifold on the outer periphery of the cell for supplying or recovering air or fuel to each cell body. be.

In addition, the internal manifold part is characterized by performing gas sealing by being compressed through a gas furnace and soot material, and the outer peripheral part of the seal plate constitutes a part of the internal manifold. The feature is that a gas-tight dense ceramic film is formed between the three-layer film, the seal plate, and the substrate for sealing, and either glass or ceramic powder is formed on the battery three-layer film, the seal plate, and the substrate. The seal plate is sealed with a three-layer battery film, and the seal plate is provided with wrinkles for absorbing deformation. The solid electrolyte fuel cell described above is characterized in that it is made of chromite.

[Function] According to the solid oxide fuel cell of the present invention, the three-layer membrane of the cell is only in the center of the separator, and the outer peripheral part is a seal plate to seal the gas around the three-layer membrane, so the internal manifold part is It is spatially separated from the battery 3-layer membrane, and the separator material is made of a thin plate, so even if the internal manifold part is compressed into the gas seal receptacle, the battery 3-layer membrane part
Optimal current-carrying contact can be ensured without being significantly affected by the internal separator's clamping.

Next, examples of the present invention will be described.

[Example] Figure 1 is an explanatory diagram of a solid oxide fuel cell based on an example of the present invention, and Figures 2 (a) to (d) are illustrations of a solid oxide fuel cell that is an example of the battery of the present invention. FIG. 3 is an explanatory diagram of an embodiment of the gas seal, and FIG. 3 is an explanatory diagram showing the joining of a substrate and a metal foil.

In the figure, 9 is a separator, 10 is a spacer, 15 is a three-layer battery membrane, 17 is an internal manifold, 18 is a film forming substrate, 19 is a seal plate, 20 is an airtight material, 21 is a ceramic powder, and 22 is a wrinkle for absorbing deformation. , 23 are ceramic vapor gaskets.

The solid oxide fuel cell of the present invention has the following configuration.

■As shown in Figures 1 and 2, the separator 9 is corrosion resistant,
It is made of a heat-resistant alloy and has many protrusions on its surface, and a manifold 17 for supplying or exhausting air and fuel is provided on the outer periphery of the separator 9.

(2) A three-layer battery film 15 consisting of a fuel electrode, a solid electrolyte, and an air electrode is formed on the surface of a porous conductive film-forming substrate 18 by a thermal spraying method or the like.

(2) The battery 3 contact membrane 15 is placed only in the center of the separator 9, keeping a distance from the internal manifold 17.

■The separator 9 has a thin plate structure, and between the separator 9 and the spacer 10 and between the spacer 10 and the seal plate 19,
Insert the ceramic paper gas furnace Soto 23.

■The seal plate 19 is a thin plate made of the same material as the separator 9, and is in the form of a foil as shown in FIG. put.

(2) Gas sealing between the battery 3 contact membrane 15 and the metal foil seal plate 19 is performed using the method shown in FIGS. 2(a) to 2(d) below.

(a) As shown in FIG. 2(a), a dense gas-tight ceramic film (for example, lanthanum chromite) 20 is formed on the substrate 18 between the battery three-layer film 15 and the seal plate 19.

(b) As shown in FIG. 2(b), the battery three-layer membrane 15
A step is provided, and the seal plate 19 is stacked on this step,
An airtight material 20 is formed in the same manner as in FIG. 2(a).

(C) As shown in FIG. 2(e), glass or ceramic powder 21 is filled.

(d) Alternatively, as shown in FIG. 2(d), the battery three-layer film 15 is also formed on the seal plate 19 and sealed.

Note that the seal brake 19 may be provided with deformation absorbing wrinkles 22 for absorbing relative deformation between the battery three-layer membrane 15 and the separator 9.

The electrode of the present invention is applicable not only to a flat plate type solid electrolyte fuel cell as shown in FIG. 1, but also to a multi-tube type solid electrolyte fuel cell.

[Effects of the Invention] According to the solid electrolyte fuel cell of the present invention, 1) the internal manifold portion has a structure that can be clamped, and gas sealing properties are improved.

2) The contact between the battery three-layer membrane and the separator for energization is
Good energizing contact can be obtained without being affected by the clamping of the internal manifold part.

It has the following effects.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a solid oxide fuel cell according to an embodiment of the present invention, and FIGS. 2(a) to (d) are embodiments of gas seals of the solid oxide fuel cell which are embodiments of the battery of the present invention. An explanatory diagram of an example, Fig. 3 is an explanatory diagram showing the bonding of a substrate and metal foil (foil), Fig. 4 is an explanatory diagram of the principle of a fuel cell, and Fig. 5 is an explanation of a conventional flat plate solid electrolyte fuel cell. Figures 6 and 7 are explanatory diagrams of electrode members of conventional solid oxide fuel cells, and Figures 8(a) to 8(c) are problems with seals of conventional solid oxide fuel cells. It is an explanatory diagram of points. In the figure, 1: solid electrolyte, 2: air electrode, 3: fuel electrode, 4: electrode member, 5: distributor, 6: interconnector, 7: 0 ring, 8: groove, 9: separator, 10 varnish spacer, 11, 12: Passageway, 13: Supply channel, 14: Discharge channel, 15: Battery three-layer membrane, 16: Adhesive, 17: Internal manifold, 18: Film-forming substrate, 19: Seal plate,
20: Ceramic membrane, 21: Ceramic powder, 22: Deformation absorbing wrinkles, 23: Gasket.

Claims (8)

[Claims] (1) A battery body consisting of a three-layer battery consisting of a fuel electrode, a solid electrolyte, and an air electrode formed on a conductive and gas-permeable substrate, and the outer periphery of the battery to maintain gas-tightness. A seal plate bonded to the battery body and a separator having a large number of protrusions in the portion that contacts the battery body are alternately laminated to seal between the battery three-layer membrane, the seal plate, and the substrate, and the outer peripheral portion of the battery is sealed. A solid oxide fuel cell comprising an internal manifold for supplying or recovering air or fuel to each cell body. (2) The solid oxide fuel cell according to claim 1, wherein the internal manifold portion performs gas sealing by being compressed through a gasket material. (3) The solid oxide fuel cell according to claim 1 or 2, wherein the outer peripheral portion of the seal plate constitutes a part of an internal manifold. (4) Between the battery three-layer film, the seal plate and the substrate,
4. The solid oxide fuel cell according to claim 1, wherein a gas-tight, dense ceramic membrane is formed and sealed. (5) On the battery three-layer film, seal plate and substrate,
4. The solid oxide fuel cell according to claim 1, wherein the solid oxide fuel cell is filled with either glass or ceramic powder and sealed. (6) The solid oxide fuel cell according to any one of claims 1 to 3, wherein the seal plate is sealed with the cell three-layer membrane. (7) The solid oxide fuel cell according to claim 1, wherein the seal plate is provided with wrinkles for absorbing deformation. (8) The solid oxide fuel cell according to claim 4, wherein the ceramic is lanthanum chromite.