JPH0652881A - Solid electrolyte fuel cell of internal manifold type - Google Patents

Abstract

PURPOSE:To enhance the output density of a fuel cell without lowering mechanical strength and to enhance the productivity and serviceability of the fuel cell by arranging the coplanar unit cells of a unit cell collective set so that adjacent cells have different polarities. CONSTITUTION:A fuel cell comprises a number of unit cell collective sets 9 stacked on stop another via gas passage members 11 each having a manifold through hole 14, each of the cell sets 9 having a plurality of flat units cells 1 arranged coplanar with one another using a cell frame portion 6 having a manifold through hole 14. The coplanar unit cells 1 of each set 9 are arranged so that adjacent cells have different polarities. An effective electrode reaction area can then be increased per stage of laminate without causing the deterioration of mechanical strength and so output density is increased and anode and cathode terminals can be taken out from the same direction, whereby the productivity and serviceability of the fuel cell are remarkably enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal manifold type solid electrolyte type fuel cell, and particularly to an internal manifold type solid electrolyte type fuel cell having high productivity and capable of easily forming cells having various outputs. Regarding fuel cells.

[0002]

2. Description of the Related Art A solid oxide fuel cell has a unit cell composed of a solid electrolyte membrane and a fuel side electrode membrane and an oxygen side electrode membrane, which are laminated on both sides of the solid electrolyte membrane, for example, through a gas separator. A large number of these cells are stacked and these single cells are electrically connected in series or in parallel, and are attracting attention as a battery having no electrolyte leakage and a high reaction rate.

Such a solid oxide fuel cell (hereinafter,
In order to improve the output density in SOFC, it is necessary to widen the area of the single cell to increase the effective area that contributes to the electrode reaction, or to increase the number of stacked single cells. In order to increase the effective area that contributes to the electrode reaction, the electrode area of each single cell may be increased, but a large area single cell has many manufacturing problems,
Since the mechanical strength is low, the strength when the fuel cell stack is constructed is lowered, and there is a problem that it is not practical.
In addition, it is difficult to equalize the temperature distribution within one cell, which often causes operational difficulties.

On the other hand, recently, there has been developed a fuel cell in which a plurality of unit cells are grouped in the same plane and are held in, for example, a square shape and are stacked. FIG. 19 is a perspective view in which a cell portion of a conventional molten salt fuel cell having an assembled cell structure is partially disassembled. In the figure, four unit cells each consisting of an electrolyte membrane 101 and an oxygen-side electrode membrane 102 and a fuel-side electrode membrane 103, which are respectively laminated on both sides thereof, are composed of a frame 105.
It is held in the shape of a rice field by. Reference numeral 104 denotes a current collector plate that is in contact with each electrode surface.

A large number of single cell assemblies having such a structure are stacked, for example, via a separator or a connector to form a fuel cell stack. FIG. 20 is an explanatory diagram showing the structure of a fuel cell stack in which the single cell assemblies are stacked.
In the figure, a large number of single cell aggregates 106 in which four single cells are aggregated in a square shape are sandwiched by a wind wheel 107 and are stacked via a biopolar plate 108, and the single cell aggregate 106 is placed on the uppermost part. A base plate 109 having a cathode terminal is arranged, and a base plate 110 having an anode terminal is arranged at the bottom. The fuel gas as the electrode active material and the oxygen-containing gas are introduced into the fuel cell stack having such a configuration from one end of the base plate 109 having the cathode terminal. These electrode active materials are supplied to the electrode surface of each unit cell through the internal manifold.
It is discharged from the other end of the base plate 109. An electrode reaction occurs in each single cell of the fuel cell stack supplied with the cell active material, and the generated electric energy is extracted to the outside via the cathode terminal and the anode terminal.

However, in such a conventional internal manifold type solid oxide fuel cell, all the same surfaces of the single cell assembly have the same polarity, and the output terminals are attached to the upper and lower ends of the fuel cell stack. Therefore, there is a problem that productivity is low and there are many inconveniences in use.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art, to improve the output density without lowering the mechanical strength, and to improve productivity and practicality. An object is to provide an improved internal manifold type solid oxide fuel cell.

[0008]

To achieve the above object, the present invention provides a unit cell assembly in which a plurality of flat unit cells are arranged on the same plane by a frame having a through hole for the manifold. In a solid electrolyte fuel cell of an internal manifold type in which a large number are laminated via a gas flow path member having a through hole, single cells on the same plane of the single cell assembly are arranged so that polarities are different between adjacent single cells. It is characterized by having done.

[0009]

A plurality of unit cells are held on the same plane by a frame body to form a unit cell aggregate, and a large number of the unit cells are laminated so that the electrode reaction per one stage of the laminate can be prevented without lowering the mechanical strength. Since the effective area that contributes can be widened, the power density of the fuel cell stack increases. Also,
By arranging each unit cell in the unit cell aggregate so that the polarity is different for each adjacent unit cell, electrical connection between the unit cell groups (hereinafter referred to as unit cell laminated body parts) stacked one above the other Can be performed by connecting the upper ends and the lower ends of the adjacent single-cell laminated body portions, and by changing the connection method, a high-voltage low-current type or a low-voltage high-current type can be obtained. Also, the anode and cathode output terminals can be provided at the same end of the fuel cell stack.

In the present invention, a single cell is the smallest unit of a battery, and is composed of a solid electrolyte membrane and a fuel side electrode membrane and an oxygen side electrode membrane which are laminated on both sides of the solid electrolyte membrane. As the solid electrolyte membrane material, for example, Zr
_{O 2 -Y 2 O 3 (YSZ} ), ZrO 2 -CaO (CS
Z), CeO ₂ —CaO, CeO ₂ —Y ₂ O ₃ type materials are used. As the oxygen-side electrode material, for example, lanthanum-based LaCoO ₃ , La _1-x Sr _x MnO ₃ , L
a _1-x Ca _x MnO ₃ or the like is used as the fuel-side electrode material, for example, nickel-based NiO—ZrO ₂ —Y ₂ O ₃ or the like is used.

In the present invention, the single cell assembly is a plurality of flat single cells held on the same plane by using a frame, and the frame is an electrically defective conductor, for example, alumina. Composed of ceramics such as. The frame body has through holes for forming a manifold through which the battery active material flows,
Further, a through hole for gas flow is provided for allowing the battery active material to flow between the upper and lower single cell aggregates.

In the present invention, the gas flow channel member is a member which is disposed between the unit cell aggregates to electrically connect the upper and lower unit cells and to form a gas flow channel. It has a similar shape, for example, a rectangle. The gas flow path member is mainly composed of a frame part joined to the frame part of the single cell assembly, a flat plate part surrounded by the frame part, and an electronic flow path provided through the flat plate part. In the same manner as the single cell assembly, the frame portion is provided with a manifold through hole. Further, in the inner frame portion that partitions the flat plate portion, at a position corresponding to the through hole for gas circulation provided in the inner frame portion of the single cell assembly, a guide slit for guiding the gas circulation direction is provided. There is.

In the present invention, a plurality of single cell aggregates are laminated to form a module unit. The electrical connection of the unit cell stack portions in the module unit in which the unit cell aggregates are stacked is performed by connecting the electrode surfaces of the unit cell stack portions adjacent to each other at their lower ends and a pair of adjacent unit cells at the upper end. This is performed by connecting the electrode surfaces of the cell stack portion, and the remaining pair of electrode surfaces are provided with the anode and cathode terminals, respectively.

When it is desired to further stack the module units having the unit outputs having the above-mentioned structure, the conductive flat plate and the manifold gas seal packing may be sandwiched between the upper and lower ends of each module unit and stacked. A single module unit or a laminated body of a plurality of module units (hereinafter referred to as a module) is used as a fuel cell stack.
For example, the solid electrolyte fuel cell is housed in a box kept in a reducing atmosphere.

In the present invention, the supply of the cell active material to the fuel cell is performed through the manifold formed in the fuel cell stack. The battery active material supplied through the manifold is supplied to each single cell through a guide slit provided in the frame portion of the gas flow path member and a gas flow through hole provided in the frame portion of the single cell assembly. It

[0016]

EXAMPLES Next, the present invention will be described in more detail by way of examples. FIG. 1 shows an internal manifold type SOF according to the present invention.
1 is a perspective view showing a single cell assembly forming C, and FIG.
2 is a sectional view taken along line II-II of FIG. 3, and FIG. 3 is an exploded view of FIG. In the figure, four single cells 1 are cell frame parts 6
The cells are grouped into a rice field shape to form a single cell aggregate 9. The individual unit cells 1 are arranged upside down with respect to adjacent unit cells so that different electrode films are adjacent to each other on the same surface. The cell frame portion 6 is made of a ceramic such as alumina which is an electrically poor conductor, and has a manifold through hole 7 at two corners of each unit cell 1, and a central cross-shaped frame portion and a side facing this. A through hole 8 for gas circulation is provided in each. Therefore, in plan view,
Each of the unit cells 1 having a substantially square shape is fitted into the projecting portion of the manifold through hole 7 of the cell frame portion 6, so that the corner portion 2 thereof is formed.
The part is a notch 10.

The gas flow path member is a member of the single cell assembly 9
For intermediates placed between, and for the top and bottom
There are one for the top and one for the bottom, which are arranged
For example, it has a rectangular shape similar to that of the single cell assembly. Figure
4 is a perspective view showing the intermediate gas flow path member, and FIG.
6 is a cross-sectional view taken along the line V-V of FIG.
FIG. In the figure, this intermediate gas
The flow path member 11 is opposed to the cell frame portion 6 of the single cell assembly 9.
Accordingly, the frame portion 12 formed in a T-shape and the frame portion 12
A flat plate part that acts as a gas separator divided into four parts
13 and an electron channel 15 penetrating the flat plate portion 13
And the two corners of the flat plate portion 13 are
Similar to the single cell assembly 9, through holes 14 for manifold
Is provided. A guide slip is attached to the central cross-shaped frame.
The through hole 1 with a slit 16 in the frame portion of the peripheral portion.
7 are provided respectively. Through hole with slit 17
On the adjacent sides in different vertical directions.
The lit is cut off. Guide slit 16 and pickpocket
The slit shape of the through hole 17 with a stopper prevents gas flow.
A shape with low flow resistance that is suitable for
Is preferred. The gas flow path member having such a configuration is
Similar to the cell frame portion 6 of the cell assembly, a ceramic that is a defective conductor
It is composed of a mix, and only the electronic channel 15 is
If LaCrO ₃System, LaMnO₃System, LaCoO₃System
Electronically conductive ceramics or mixtures of these with metals
It is composed of baked bodies.

FIG. 7 is a perspective view of the gas passage member for the upper end, FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7, and FIG. 9 is a sectional view taken along line IX-IX in FIG. , Again FIG.
FIG. 8 is a perspective view showing the back side surface of FIG. 7. In the figure, the upper gas passage member 18 has no through holes for the gas passage in the frame portion around the upper end, but the through holes 14 for the manifold are provided at two corners of the flat plate portion 13. One of them is a through hole 19 for a manifold with a slit. Further, a guide slit 16 having a gas distribution function is provided in the central cross-shaped frame portion on the lower side surface facing the unit cell assembly. The upper end gas flow path member 18 having such a configuration is
It has the role of taking gas from the manifold into the fuel cell stack and guiding the gas from the fuel cell stack to the manifold.

FIG. 11 is a perspective view showing the inner surface of the lower end gas flow path member. The lower end gas flow path member 20 is similar to the upper end gas flow path member 18 in the fuel cell stack. It is configured to guide gas to the manifold and to take gas from the manifold into the fuel cell stack. The unit cell assembly 9 having such a configuration and the gas flow path members 11, 18 and 20 are pressure-bonded at high temperature to form a module unit. At this time, the single cell assembly 9
A current collector plate 5 is bonded to the electrode surface of each unit cell 1 of the above, and each of the unit cells 1 stacked on top of each other has an electron channel 1 of a gas channel member 9.
5 and the current collector 5 are electrically connected in series.
FIG. 12 is a perspective view of a module unit in which a large number of single cell assemblies 9 are stacked with the intermediate gas flow path member 11 interposed therebetween.
In the figure, a large number of single cell aggregates 9 are stacked via a gas flow path member 11, a gas flow path member 18 for the upper end is arranged at the uppermost stage, and a gas flow path member 20 for the lower end is arranged at the lowermost stage. Has been done.

The electrical connection in the module unit in which a predetermined number of single cell aggregates are laminated in this way is performed by pressing metal collecting felts onto the upper and lower ends of each single cell laminated body,
This is performed using the output terminal board and the stack connection terminal board. FIG. 13 shows the SOF using the module unit alone.
It is explanatory drawing at the time of comprising C. In the figure, two pairs of lower side surfaces of each unit cell laminated body portion are electrically connected to each other by a conductor on the lower side surface of the module unit 21, and an upper surface connects a pair of surfaces of adjacent single cell laminated body portions. The anode and cathode output terminal plates 23 are arranged on the other pair of surfaces, respectively. At this time, it is preferable to close only the unused one of the manifold through holes at the corner of the gas flow path member with the lid 24.

When a plurality of module units 21 are laminated and used, metal felts for current collection are separately attached to the upper and lower end portions of the module units 21 respectively, and the layers are sequentially laminated. To be done. FIG. 14 is an explanatory diagram showing an example of an electrical connection method when stacking a plurality of module units 21. In the figure, module unit 2
Separate terminal boards 2 at the top and bottom of each single cell stack
2 are joined together, and a plurality of such module units are laminated to form a module unit laminated body (module). At this time, it is preferable to insert a high temperature gasket in the frame portion between the module units and seal the manifold.

FIG. 15 is a perspective view of a module 25 in which five module units 21 are stacked. The connection of the unit cell laminated body portions in the uppermost and lowermost module units 21 is the same as in the case of using the single module unit. In this case, if the two pairs of two surfaces of the unit cell laminated body part of the lowest module unit are electrically connected by the conductors respectively, the output of the module can be adjusted arbitrarily by changing the connection on the top surface. can do. The upper end of the manifold is closed by a lid 24.

It is also possible to connect a plurality of, for example, four modules 25 having such a structure to form a fuel cell. In this case, the electrical connection of each module is high voltage low current type, medium voltage medium current type or high current low voltage type, etc.
The connection method can be selected according to the purpose of use of the fuel cell. 16A and 16B show a method of connecting the module 25. FIG. 16A is a medium-voltage medium-current type in which two modules are connected in series using the module connecting conductors 26 and the two groups of modules connected in series are further connected in parallel. On the other hand, FIG.
(B) is a high-voltage low-current type in which all the modules are connected in series by the module connecting conductors 26.

The fuel cell stack 27 constructed by electrically connecting a plurality of modules 25 in this manner is housed in a box 28 lined with a heat insulating material, which is maintained in a reducing atmosphere, for example, and is housed in a fuel cell. Becomes FIG. 17 is an explanatory diagram showing a state in which the high-voltage low-current type fuel cell stack 27 is housed in the box 28. In the figure, four modules 2
A fuel cell stack 27 in which 5 is connected to a high-voltage low-current type is housed in a box 28. An air pipe 30 for introducing air into the box 28, and a fuel gas pipe 3 for introducing fuel gas
1 and a reducing gas pipe 32 for introducing a reducing gas for maintaining the inside in a reducing atmosphere are connected.
Further, the upper portion of the box body 28 is closed by a strong lid 35 in order to apply pressure to the gasket of the connecting portion of the module 25.

Air and fuel gas are supplied to the thus constructed fuel cell through an air pipe 30 and a fuel pipe 31, respectively. FIG. 18 shows the flow state of air and fuel gas in one module unit of a high-voltage low-current fuel cell. Air pipe 30 and fuel gas pipe 3
The air and fuel gas supplied to the fuel cell via 1 are
Flow through the manifold formed at the corner of the module unit,
Through the through-hole 19 for the manifold with slits of the gas flow path members 18, 20 at the upper end or the lower end, it flows on the single cell electrode at the uppermost stage or the lowermost stage, and the guide slit 16 of the intermediate gas flow channel member 11 or the through hole with slits. Flows sequentially through the holes 17 and the gas passage through holes 8 of the unit cell assembly 9, and flows out from the gas manifold provided at another corner via all the unit cell electrode surfaces. The fuel gas and the oxygen-containing gas respectively flow into two systems in the module unit, and these two gases are in a cross flow on the plan view. The air flow and the fuel gas flow are parallel flows for each module unit.

In this way, an electrode reaction occurs in each unit cell supplied with air and fuel gas (for example, hydrogen), and electric energy is generated. The generated electric energy is collected and taken out to the outside as a stronger electric energy through the output terminal. According to this embodiment, the single cell assembly 9
By arranging the single cells 1 in FIG. 1 so that the adjacent single cells are upside down and having different polarities, the anode and the cathode terminals can be taken out from the same direction, so that the module 25 can be connected easily and the productivity and productivity can be improved. Practicality is significantly improved. In addition, since the fuel cell stack 27 is configured by combining the module units 21 or the modules 25 having a predetermined output, it is possible to quickly meet various output needs.

According to this embodiment, since the manifold through hole 14 is formed by cutting out a part of the single cell assembly 9 and the gas flow path member 11, the outer surface of the module becomes flat. It can be arranged in high density. Also, by stacking the small module units while sandwiching the gas seal packing and the metal for electrical connection, the module replacement unit is downsized, and
Maintenance costs are reduced.

According to the present embodiment, since the electrode active material flows in parallel for each module 25, it is possible to stop the gas of each module alone, and it is possible to promptly deal with a failure. Further, by setting the inside of the box body 28 accommodating the fuel cell stack 27 in a reducing atmosphere, a metal having excellent electrical conductivity can be used as the module connecting conductor 26.

In the present embodiment, it is preferable that the number and cross-sectional area of the electronic flow paths 15 of the gas flow path member be changed and optimized in consideration of output specifications and the like. Further, the current collector used when stacking the single cell aggregates preferably has a fuel reforming catalytic action. Further, it is preferable to dispose a heating element for heating inside the heat insulating material lined with the box body 28. This facilitates maintaining the fuel cell at the optimum operating temperature.

[0030]

According to the present invention, the arrangement of the unit cells in the unit cell assembly is set to be upside down for each adjacent unit cell so that the polarities are made different, so that the anode and cathode terminals can be taken out from the same direction. Therefore, the productivity and the practicability are remarkably improved. In addition, since the fuel cell is configured by combining the module units having a predetermined output or the modules, it is possible to quickly meet various output needs.

[Brief description of drawings]

FIG. 1 is a perspective view showing a single cell assembly for constructing an SOFC according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an exploded view of FIG.

FIG. 4 is a perspective view showing an intermediate gas flow path member.

5 is a sectional view taken along the line VV of FIG.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a perspective view of an upper end gas flow path member.

8 is a sectional view taken along line VIII-VIII of FIG.

9 is a sectional view taken along line IX-IX of FIG.

FIG. 10 is a perspective view showing an inner surface of a gas passage member for an upper end.

FIG. 11 is a perspective view showing the inner surface of the lower gas flow path member.

FIG. 12 is a perspective view showing a module unit.

FIG. 13 is an explanatory diagram showing an electrical connection method within a module unit.

FIG. 14 is an explanatory diagram showing a connection method when a large number of module units are stacked.

FIG. 15 is an explanatory diagram showing a connection method within a module.

FIG. 16 is a perspective view showing a medium-voltage medium-current type fuel cell stack and a high-voltage low-current type fuel cell stack.

FIG. 17 is an explanatory diagram showing a configuration of a power generation module.

FIG. 18 is an explanatory view showing the flow of gas in the module.

FIG. 19:

FIG. 20 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Single cell, 2 ... Oxygen electrode membrane, 3 ... Fuel electrode membrane, 4 ... Solid electrolyte membrane, 5 ... Current collector plate, 6 ... Cell frame part, 7 ... Manifold through hole, 8 ... Gas distribution through hole, 9 ... Single cell assembly, 1
0 ... notch part, 11 ... intermediate gas flow path member, 12 ... frame part,
13 ... Flat plate part, 14 ... Manifold through hole, 15 ... Electronic flow path, 16 ... Guide slit, 17 ... Slit through hole, 18 ... Upper end gas flow path member, 19 ... Manifold through hole with slit, 20 ... Lower gas flow path member, 2
1 ... Module unit, 22 ... Stack connection terminal plate, 2
3 ... Output terminal plate, 24 ... Manifold through-hole lid, 2
5 ... Module, 26 ... Conductor for module connection, 27
… Fuel cell stack, 28… Box, 30… Air piping, 3
1 ... Fuel gas piping, 32 ... Reducing gas piping, 35 ... Lid.

Front page continuation (72) Inventor Teruo Oda 3-1-1 Tam, Tamano City, Okayama Prefecture Mitsui Engineering & Shipbuilding Co., Ltd. Tamano Office

Claims (1)

[Claims] 1. A plurality of single cell aggregates in which a plurality of flat plate-shaped single cells are arranged on the same plane by using a frame body having through holes for manifolds are stacked through a gas flow path member having through holes for manifolds. In the solid electrolyte fuel cell of the internal manifold type, the internal manifold type solid electrolyte characterized in that the single cells on the same plane of the single cell assembly are arranged so that the polarities are different between adjacent single cells. Type fuel cell.