JP2001068132A - Current collector plate and solid electrolyte fuel cell using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure electric conduction between flat unit cells and provide a fuel cell in which no excessive load can be exerted on the flat unit cell due to a thermal stress or the like. SOLUTION: A solid electrolyte fuel cell 4 comprises a flat unit cell 6, a first spacer 8, a second spacer 10 and metal thin plates 11, 12 forming current collecting plates. The metal thin plate 11 is provided with projections projecting at the obverse and reverse by pressing, and the metal thin plate 12 is provided with projections projecting at the obverse and reverse. The projection is formed in such a height as to be brought into contact with the surface of a fuel or air electrode when the solid electrolyte fuel cell 4 is laminated. Consequently, the metal thin plate 12 defines a fuel gas passing portion and an oxidant gas passing portion. The projections of the metal thin plate 11 is brought into elastic contact with the fuel electrode of the solid electrolyte fuel cell 4 and the air electrode of the other solid electrolyte fuel cell 4, thereby achieving the electric conduction between the electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolyte fuel cell in which a flat plate cell and a separator are stacked, and more particularly, to ensuring mutual energization between the flat plate cells, separation of gas passages, and temperature change. The present invention relates to a solid electrolyte fuel cell that is prevented from being damaged by thermal stress caused by the above.

[0002]

2. Description of the Related Art Recently, fuel cells which directly convert chemical energy inherent in fuel into electric energy by using, for example, air and hydrogen as oxidizing gas and fuel gas, respectively, have attracted attention from the viewpoint of resource saving and environmental protection. Research and development are progressing because solid electrolyte fuel cells have many advantages such as high power generation efficiency and effective use of waste heat.

FIG. 13 shows a conventional plate type solid electrolyte fuel cell 100 of an internal manifold system.

In order to supply the fuel gas and the oxidizing gas to the solid electrolyte fuel cell, gas supply / exhaust holes for each gas are provided in a separator or the like of the solid electrolyte fuel cell. The one that supplies and exhausts each gas to and from the surface is called an internal manifold type.

As shown in FIG. 13, a flat solid electrolyte fuel cell 100 has a flat solid electrolyte layer 102 made of a zirconia sintered body (YSZ) doped with yttria or the like. Air electrode 1
04 and the Ni / YSZ cermet fuel electrode 106 are arranged, and the flat plate cells 108 adjacent to each other are electrically connected in series. A mesh metal 115 is disposed between the separator 110 and the fuel electrode 106, and a connection layer 117 is disposed between the separator 110 and the air electrode 104. , Separator 110, fuel electrode 106, and air electrode 1
04, and a seal member 119 is provided on the side surface to close the cover.

[0006] The flat solid electrolyte fuel cell 100
Are alternately stacked, and an oxidizing gas and a fuel gas are introduced from the passages 114, respectively.
4, and by bringing the oxidant gas and the fuel gas into contact with the surface of the fuel electrode 106, an electromotive force is generated, and output from the solid electrolyte fuel cells 100 stacked in series.

[0007]

SUMMARY OF THE INVENTION Conventional separator 110
The current collecting surface is formed flat by machining or the like,
The flat plate cell 108 has a warp or distortion generated at the time of manufacturing, and it is difficult to correct the distortion to a perfect plane by performing mechanical processing due to the material of the flat plate cell 108 or the like. . Therefore, when the separator 110 is attached to the flat cell 108, the flat cell 108 does not come into contact with the current collecting surface of the separator 110 on the entire surface, but has at most three points of contact, thereby providing good electric power. Connection state may not be obtained. Therefore, a method is considered in which the flat cell 108 is deformed, or the surfaces of the current collecting surface of the separator 110 and the flat cell 108 are brought into contact with each other using a conductive adhesive or the like. However, when joined by using a conductive adhesive, the thermal expansion characteristics of the respective members are different, so that during operation, thermal deformation due to a temperature change at the time of stop occurs, and particularly, the stress generated due to high rigidity of the separator 110 is generated. Is greatly applied to the flat cell 108, and the flat cell 108 may be damaged. Further, in this case, there is a problem that the processing cost is high and the weight is heavy.

When a plurality of flat plate cells 108 are stacked, the tightening load is increased by a ceramic separator 110.
The separator 110 and the flat cell 108 may be broken when the tightening force changes due to temperature fluctuation and the load becomes excessive when the load is excessive. Further, in order to cope with the deformation, the conducting metal 115 for electrically connecting the flat cell 108 must be strengthened.
It is conceivable that a load is applied to the plate 8 and the flat cell 108 is damaged by thermal stress or the like.

[0009]

According to the present invention, a fuel cell is constructed as follows in order to solve the above-mentioned problems.

That is, a current collector plate is formed by a metal flat plate and a thin metal plate, and a metal flat plate is provided between the stacked flat cell units to separate a fuel passage and an air passage of the flat unit cell. A thin metal plate having irregularities on its surface is attached to the flat plate, and is electrically connected to the air electrode or the fuel electrode of the flat plate cell facing the thin metal plate with elasticity.

As described above, the current collecting plate is formed by the metal flat plate and the metal thin plate, and the current collecting plate is provided between the stacked flat unit cells, so that the air is formed by the metal thin plates provided on both sides of the metal flat plate. The electrode and fuel electrode are reliably electrically connected in a good contact state, and since the thin metal plate is elastically in contact with the flat cell, the load on the flat cell can be reduced, and stress due to temperature fluctuations etc. can be reduced. It is possible to prevent the damage of the flat plate type cell which is the cause.

Further, since the flat plate cells are stacked via a metal plate, the fuel passage and the air passage can be completely separated from each other, and local distortion caused by distortion of the entire stack, warpage of the unit cell, and the like can be achieved. Stress concentration can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for energizing a fuel cell according to the present invention and an embodiment of the fuel cell will be described.

FIG. 1 is a sectional view of a fuel cell 2 of an internal manifold system. FIG. 1 is a sectional view of the fuel cell 2 in FIG. As shown in FIG.
Is formed by laminating a plurality of solid electrolyte fuel cells 4 in a predetermined number, and the solid electrolyte fuel cell 4 includes a flat cell 6, a first spacer 8, a second spacer 10, 3 are formed of a metal thin plate 11 and a metal flat plate 12.

The first spacer 8 and the second spacer 10 are substantially square as shown in FIG. 3, and are formed of a heat-resistant metal. An accommodation portion 14 for accommodating the flat cell 6 is formed at the center of the first spacer 8, and a fuel gas supply passage 22 and a fuel gas exhaust passage 24 are provided around the accommodation portion 14.
In addition, an oxidizing gas supply passage 26 and an oxidizing gas exhaust passage 28 are formed. The accommodating portion 14 has a square shape substantially equal to that of the flat cell 6 and is formed to penetrate the front and back. Fuel gas supply passage 22 and fuel gas exhaust passage 2
The oxidizing gas supply passage 26 and the oxidizing gas exhaust passage 28 are formed diagonally opposite to each other with the housing portion 14 interposed therebetween, and the fuel gas supply passage 22 and the fuel gas exhaust passage Reference numeral 24 is open to the accommodating portion 14.

The second spacer 10 has substantially the same shape as the first spacer 8 and has a cutout 20 formed in the center, and a fuel gas supply passage 22 and a fuel gas exhaust passage 2 around the periphery.
4, an oxidizing gas supply passage 26, and an oxidizing gas exhaust passage 28 are formed similarly to the first spacer 8. The notch 20 is formed slightly larger than the air electrode surface of the flat plate type cell 6 and penetrates the front and back. The fuel gas supply passage 22 and the fuel gas exhaust passage 24, and the oxidizing gas supply passage 26 and the oxidizing gas exhaust passage 28 are formed to face each other with the notch 20 interposed therebetween. A supply passage 26 and an oxidant gas exhaust passage 28 are open in the notch 20.

The flat cell 6 has a substantially square shape and a YSZ
(La, on both sides of a flat solid electrolyte layer composed of
Sr) An air electrode of MnO ₃ and a fuel electrode of Ni / YSZ cermet (both not shown) are arranged and formed. Further, the holding thin plate frame 1 is provided on the outer peripheral portion of the surface of the flat cell 6.
6 are joined by a joining material 17. The holding thin plate frame 16 has a fuel gas supply passage 22 and a fuel gas exhaust passage 2.
4, an oxidizing gas supply passage 26, and an oxidizing gas exhaust passage 28 are formed similarly to the first spacer 8, and the holding thin plate frame 16 is sandwiched between the first spacer 8 and the second spacer 10, and Battery 6 is divided into first spacer 8 and second spacer 1
It is structured to support between zero.

The metal flat plate 12 is a metal flat plate made of Inconel 600, has substantially the same outer shape as the first spacer 8, and further has a fuel gas supply passage 22 and a fuel gas An exhaust passage 24, an oxidant gas supply passage 26, and an oxidant gas exhaust passage 28 are formed similarly to the first spacer 8. In addition, the metal flat plate 12 does not need to be a perfect flat plate shape and may be appropriately curved or the like.
Further, a metal fitting for fixing the metal sheet 11 may be provided. Examples of the fixing bracket include, for example, irregularities that can be inserted and removed, protrusions that hold the periphery of the thin metal plate 11, and insertion fittings that can be inserted and removed in a slide shape.

The metal thin plate 11 is a metal plate made of Inconel 600, and has protrusions 18 formed on the front surface as shown in FIG. 2 by pressing or the like. The current collector 3 is formed by combining the metal sheet 12 with the metal sheet 12. As shown in FIG. 1, when the solid electrolyte fuel cell 4 is stacked together with the metal flat plate 12 as shown in FIG. 1, the protrusion 18 has a height that contacts the surface of the fuel electrode or the air electrode of the solid electrolyte fuel cell 4 facing the thin metal plate 11. Have. Further, the projection 18 has a moderate elasticity, and when an excessive load is applied, the projection 18 is appropriately deformed without damaging the fuel electrode, the air electrode, etc. in contact with the projection 18 to reduce the load. It is supposed to. In addition, it has a moderate deformation restoring property. Note that the metal thin plate 11 and the metal flat plate 12 are both heat-resistant alloys. If the material is such that it is difficult to form an oxide film on the surface in a high-temperature oxygen atmosphere, the above-mentioned Inconel 60 is used.
Other than 0 may be used.

Thus, when the above members and the current collector plate 3 are laminated, a passage portion through which the fuel gas is supplied to the fuel electrode is formed by the first spacer 8 and the metal flat plate 12, and the second spacer 10 and the metal flat plate are formed. 12 forms a passage portion through which the oxidant gas is supplied to the air electrode. Further, since the metal sheet 11 is provided with the projection 18, the above-mentioned respective passages are not interrupted, and one of the metal sheets 11 comes into contact with the fuel electrode of the solid electrolyte fuel cell 4, and the other of the metal sheets 11 Since it contacts the air electrode of another solid electrolyte fuel cell 4 stacked on the solid electrolyte fuel cell 4, the stacked solid electrolyte fuel cell 4
Are electrically conducted by a set of the thin metal plate 11 and the flat metal plate 12, that is, the current collector plate 3.

Next, the operation of the fuel cell 2 will be described.

As shown in FIG. 1, in the fuel cell 2, solid electrolyte fuel cells 4 are sequentially stacked and fastened in a vertical direction at a predetermined pressure by fastening means (not shown). By stacking the solid electrolyte fuel cells 4, the fuel gas supply passage 22,
The fuel gas exhaust passage 24, the oxidizing gas supply passage 26, and the oxidizing gas exhaust passage 28 are continuous and formed as respective flow passages.

Therefore, when the fuel gas flows from the fuel gas supply passage 22, the fuel gas is supplied to the fuel electrode of each solid electrolyte fuel cell 4, exhausted from the fuel gas exhaust passage 24, and exhausted from the oxidant gas. When the oxidizing gas flows from the supply passage 26, the oxidizing gas is similarly supplied to the air electrode of each solid oxide fuel cell 4 and is exhausted from the oxidizing gas exhaust passage 28.

After the fuel cell 2 is heated to a predetermined temperature and the fuel gas and the air are supplied to the fuel electrode and the air electrode of the flat cell 6 in this manner, the electromotive force is generated by the flat cell 6. Is generated, and the generated electromotive force is applied to the current collector plate 3 (the metal thin plate 11, the metal flat plate 1) for connecting the respective flat plate cells 6 in series.
2. It flows sequentially through the thin metal plate 11) and can be taken out as a current from an output terminal (not shown) of the fuel cell 2.

As described above, according to the fuel cell 2, each solid electrolyte fuel cell 4 is separated by the metal flat plate 12 to partition the passage of the fuel gas and the passage of the oxidizing gas. Since the fuel electrode and the air electrode are in contact with each other in this state, current can be efficiently extracted. Further, the metal sheet 11 has irregularities formed by press working, and since the tip of the projection 18 is in contact with the surface of the flat cell 6, each part expands and contracts due to a temperature change. Even if it occurs, the elastic deformation of the projection 18 absorbs the thermal stress to maintain the contact, so that the energization between the solid electrolyte fuel cells 4 is not interrupted, and the thermal stress does not damage the flat cell 6. .

Further, the fuel gas and the oxidizing gas supplied to the flat cell 6 are reliably separated by the metal flat plate 12, so that the fuel gas and the oxidizing gas are not mixed inside and the fuel electrode and the air are not mixed. It can flow efficiently on the pole surface.

Next, another example of the metal sheet 11 will be described with reference to the drawings.

The metal sheet 11 may have a rectangular shape as shown in FIG. In this way, the fuel electrode and the like and the metal flat plate 12 can be brought into contact with each other with a predetermined width. FIG. 7 shows a state where the metal thin plate 11 is overlaid on the metal flat plate 12. As shown in FIG. 11, the metal sheets 11 are stacked in a direction in which the fuel gas or the like passes.

Instead of a rectangular shape, a wave shape may be used as shown in FIG. Also in this case, similarly to the above example, they are arranged in accordance with the direction in which the fuel gas or the like passes.

Further, as shown in FIGS. 9 and 10, a plurality of strip-shaped metal pieces 19 are protruded from the flat metal sheet 11 by pressing or the like, and the tip of the protruded metal piece 19 is used as a fuel electrode or the like. You may make it contact an air electrode. In this way, even when the opening that penetrates the front and back sides is formed in the thin metal plate 11 by press working or the like, the gas passage between the flat plate cells 6 is blocked by the thin metal plate 12 so that the fuel gas and the oxidizing gas are Since they do not mix, the metal sheet 11 can be processed into any shape. The metal piece 19 may be attached by welding or the like. Further, the metal thin plates 11 having different shapes may be used on the front and back surfaces of the metal flat plate 12.

Further, as shown in FIG. 6, a narrowed portion 13 may be formed around the metal flat plate 12, and the narrowed portion 13 may be sandwiched by spacers. If you do this,
The degree of adhesion of the spacer can be improved, and the thermal stress can be reduced.

The shape of the flat cell is not limited to a square, and the shape is not limited to a rectangle, a circle, an ellipse or the like. A plurality of flat cells may be provided in parallel in the horizontal direction. FIG.
As shown in FIG. 2, the fuel gas supply passage 22 and the fuel gas exhaust passage 24 are opposed to each other, and the oxidant gas supply passage 26 and the oxidant gas exhaust passage 28 are opposed to each other in a direction perpendicular to the fuel gas supply passage 22. The fuel gas and the oxidizing gas may be introduced into the fuel cell 2 at right angles from the respective flow passages.

[0033]

According to the fuel cell of the present invention, a solid electrolyte fuel cell is provided by providing between the solid electrolyte fuel cells current collector plates provided with metal thin plates having irregularities on the front and back surfaces of a metal flat plate. When stacked, each flat cell is electrically connected to a thin metal plate via a metal flat plate while maintaining good contact.Moreover, since the flat cell is contacted by the thin metal plate, the fuel cell is Even if the components of the stack expand or contract due to temperature fluctuations during operation, the fluctuations can be absorbed to prevent damage to the flat cell.

Further, since the spacers are laminated via the metal flat plate, the spacers can be adhered to each other, the gas passages can be completely separated, leakage can be reliably prevented, and the stack and the like due to the difference in thermal expansion can be prevented. Damage can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a solid oxide fuel cell according to the present invention.

FIG. 2 is a perspective sectional view showing a metal thin plate.

FIG. 3 is an exploded perspective view showing one embodiment of the solid oxide fuel cell according to the present invention.

FIG. 4 is a view showing another example of a thin metal plate.

FIG. 5 is a view showing another example of a metal thin plate.

FIG. 6 is a diagram showing another example of a thin metal plate.

FIG. 7 is a perspective view showing another example of a thin metal plate.

FIG. 8 is a perspective view showing another example of a thin metal plate.

FIG. 9 is a perspective view showing another example of a thin metal plate.

FIG. 10 is a cross-sectional view showing another example of a thin metal plate.

FIG. 11 is an exploded perspective view showing another embodiment of the solid oxide fuel cell according to the present invention.

FIG. 12 is an exploded perspective view showing another embodiment of the solid oxide fuel cell according to the present invention.

FIG. 13 is a view showing a conventional solid oxide fuel cell.

[Explanation of symbols]

 Reference Signs List 2 fuel cell 3 current collector 4 solid electrolyte fuel cell 6 flat unit cell 8 1st spacer 10 2nd spacer 11 metal thin plate 12 metal flat plate 13 squeezed portion 14 accommodation portion 16 holding thin plate frame 17 bonding material 18 protrusion 19 metal piece 22 Supply passage for fuel gas 24 Exhaust passage for fuel gas 26 Supply passage for oxidant gas 28 Exhaust passage for oxidant gas

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Kentaro Ito 3-3-3308-310 F-term (reference) 5H026 AA06 CC03 CC04 CC05 CC08 EE02

Claims (12)

[Claims] 1. A metal flat plate provided between stacked flat type single cells to block the flow of gas between the flat type single cells, and provided on the front and back surfaces of the metal flat plate in contact with the metal flat plate. And a thin metal plate elastically contacting the fuel electrode or the air electrode of the flat cell provided in the flat cell, and having a function of relieving stress applied to the flat cell. A current collector plate for a solid electrolyte fuel cell. 2. The current collector plate according to claim 1, wherein the thin metal plate has a protrusion on one or both of the front and back surfaces. 3. The projection of the thin metal plate has a wavy shape, a rectangular shape,
The current collector plate according to claim 2, wherein the current collector plate is in any one of a dimple shape, a spindle shape, and a strip shape, or a combination of two or more thereof. 4. A fuel cell comprising a flat plate type cell in which a fuel electrode and an air electrode are provided opposite to each other on the front and back surfaces of a plate type solid electrolyte. A metal flat plate for blocking gas flow between the cells is arranged, and a thin metal plate having irregularities is attached to the front and back surfaces of the flat metal plate in a state of being in contact with the flat metal plate, respectively, by the unevenness formed on the thin metal plate. A method of laminating solid electrolyte fuel cells, characterized in that the flat plate cells sandwiching the flat metal plate are electrically connected to each other, and the stress applied to the flat plate cells is reduced by the unevenness. 5. The unevenness of the thin metal plate is wavy, rectangular,
5. The method for laminating a solid electrolyte fuel cell according to claim 4, wherein the method is a dimple shape, a spindle shape, a strip shape, or a combination of two or more thereof. 6. A flat cell having a fuel electrode and an air electrode opposed to each other on the front and back surfaces of a flat solid electrolyte, and provided between the stacked flat cells and between the flat cells. A metal flat plate that blocks the flow of gas, and provided on the front and back surfaces of the metal flat plate, respectively, in contact with the front and back surfaces of the metal flat plate, and is elastic on the fuel electrode or air electrode of the flat plate cell. And a thin metal plate for conducting the air electrode and the fuel electrode of the laminated flat cell through the flat metal plate. . 7. A flat cell having a fuel cell and an air electrode opposed to each other on the front and back surfaces of the flat solid electrolyte, a housing portion for housing the flat cell in a central portion, and A fuel gas supply hole and a fuel gas exhaust hole, and an oxidizing gas supply hole and an oxidizing gas exhaust hole are formed so as to face each other with the housing portion interposed therebetween, and the fuel gas supply hole and the fuel gas exhaust hole are formed so as to face each other. A first spacer having an opening in the housing portion, and a cutout larger than an air electrode of the flat plate type cell at the center, and a fuel gas supply hole, a fuel gas exhaust hole, an oxidant gas supply hole, A second spacer having an oxidizing gas supply hole and an oxidizing gas exhaust hole formed in the notch, each of which has the same agent gas exhaust hole as the first spacer, and is stacked on the second spacer; The cutting of the second spacer A metal flat plate for closing a notch; and a metal plate provided on the front and back surfaces of the metal flat plate, the metal flat plate and the air electrode of the flat plate type cell, and the metal flat plate and the second flat plate.
A solid electrolyte fuel cell, comprising: a set of thin metal plates that are in contact with the fuel electrode of the next flat plate cell stacked on the spacer. 8. The solid electrolyte fuel cell according to claim 7, wherein the spacer is made of heat resistant steel formed by alumina forming. 9. A holding thin plate frame attached to the periphery of the flat cell and closing the periphery of the flat cell when the flat cell is accommodated in the first spacer. The solid electrolyte fuel cell according to claim 7 or 8, wherein 10. An aperture is formed around the flat metal plate,
The solid electrolyte fuel cell according to any one of claims 7 to 9, wherein a stress located in a direction perpendicular to the laminating direction of the flat plate cells is also alleviated by an aperture located inside the spacer. . 11. The solid electrolyte fuel cell according to claim 6, wherein the thin metal plate has an elastic projection on one or both of the front and back surfaces. 12. The method according to claim 11, wherein the protrusion of the metal thin plate has any one of a wave shape, a rectangular shape, a dimple shape, a spindle shape, and a strip shape, or a combination of two or more thereof. Solid electrolyte fuel cell.