JPH09274927A - Solid electrolyte type fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for separately providing collector for leads by providing conductivity to sealer. SOLUTION: A plurality of single cells 11 is incorporated in parallel in a housing with two opposing sides opened, and the opened sides of the housing are sealed by a metallic sealer 13 which may be semi-melted at the battery operating temperature such as aluminum alloy so as to prevent leakage of fuel gas to be supplied in the housing. Thus edges of collector 12 attached to the outer circumference of each single cell 11 is electrically connected to one of air electrode 11b extending from the edge of adjoining single cell 11 by means of the metallic sealer 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell using a metal sealing material.

[0002]

2. Description of the Related Art Solid oxide fuel cells are manufactured, for example, from yttria-stabilized zirconia (YS) having oxygen ion permeability.
Z) or calcia-stabilized zirconia (CSZ), sandwiching a solid electrolyte between them, an air electrode made of a perovskite-type lanthanum-based oxide and a fuel electrode mainly made of nickel are provided, and they are made to flow facing each of these electrodes. Electromotive force is obtained by electrochemically reacting air and fuel gas via a solid electrolyte. In this type of fuel cell,
Since it is necessary to separate the fuel gas channel and the air channel in an airtight state, for example, in the case of a single cell in which a fuel electrode is provided on the inner surface of a cylindrical solid electrolyte and an air electrode is provided on the outer surface, this cylindrical shape is used. It is known that the fuel gas is circulated so as to come into contact with the fuel electrode on the inside of the unit cell and the outside air electrode is formed so as to come into contact with the outside air to obtain electric power. In this case, since the electric power obtained by the single cell is small, it is general that a plurality of single cells are arranged in parallel and electrically connected in parallel or in series by the current collecting member to obtain the required electric power.

2 to 4 show a conventional solid oxide fuel cell, FIG. 2 is a perspective view showing a cylindrical single cell, and FIG. 3 is an example of a conventional cylindrical single cell gas seal structure. FIG. 4 is a schematic explanatory view showing another conventional gas seal structure.

As shown in FIG. 2, the unit cell 1 includes an air electrode (anode) on the inner peripheral surface of a solid electrolyte 1a formed in a cylindrical shape.
1b, a fuel electrode (cathode) 1c is formed on the outer peripheral surface of the solid electrolyte 1a.
Cylindrically extending from both ends. And
As shown in FIG. 3, a plurality of unit cells 1 each having a current collector 2 attached to an outer fuel electrode 1a are connected to the air electrodes 1 at both ends of each unit cell 1.
The housings are arranged in parallel in a housing (not shown) whose two opposite sides are open so that b is exposed, and the housing is opened so that fuel gas supplied to the inside of the housing does not leak to the outside. The part (one is omitted) is hermetically sealed with glass 3.

At this time, the insides of the tubular air electrodes 1b at both ends of each unit cell 1 communicate with the outside of the housing, and the end of the current collector 2 attached to the outer peripheral surface of each unit cell 1 has one end. The air electrode 1b side is made to extend airtight from the sealing portion made of glass 3. Then, the end portion of each current collector 2 extended from the seal portion of the glass 3 has a connection current collecting member 4
Are connected to the air electrodes 1b of the adjacent single cells 1 via. In this way, a plurality of unit cells 1 are connected in series and stacked to form a solid oxide fuel cell. The glass 3 seals the glass 3 in a semi-molten state to maintain the sealing property when heated during battery operation, and also absorbs the difference in thermal expansion between each single cell 1 and the housing, etc. It is designed to prevent

Further, as shown in FIG. 4, a plurality of unit cells 1
A housing (not shown) whose two opposite sides are open
Inside, they are arranged side by side in parallel, and the open portion of the housing is hermetically sealed with glass 3.
At this time, the insides of the tubular air electrodes 1b at both ends of each unit cell 1 communicate with the outside of the housing, and each unit cell 1
The ends of the current collectors 2 attached to the outer periphery of the are connected in advance to the air electrodes 1b of the adjacent single cells 1 via the connection current collecting members 5, and the connection current collecting members 5 are sealed by the glass 3. It is designed to be embedded in the department. In this way, a plurality of unit cells 1 are connected in series and stacked to form a solid oxide fuel cell.

[0007]

In the former conventional solid oxide fuel cell described above, the open portion of the housing accommodating the plurality of unit cells 1 is hermetically sealed by the glass 3 and then the glass 3 portion. It is necessary to electrically connect the end of the current collector 2 extending from the air electrode 1b to the air electrode 1b of the adjacent single cell 1 by the connection current collecting member 4. This connection work is complicated and troublesome. At the same time, the connecting current collecting member 4 protrudes outside the housing, and the device becomes large accordingly.

Further, in the latter conventional solid oxide fuel cell, the device can be downsized because the connecting current collecting member does not protrude to the outside as compared with the former, but before sealing by the glass 3, However, the complicated work of electrically connecting the current collector 2 and the air electrode 1b of the adjacent single cell 1 by the connection current collecting member 5 is required, and there is a problem that productivity is poor.

The present invention has been made in view of the above circumstances, and provides a solid oxide fuel cell which does not require the work of connecting an air electrode and a current collector when stacking a plurality of single cells. With the goal.

[0010]

In order to solve the above problems, in the present invention, a fuel electrode is formed on one side and an air electrode is formed on the other side with a solid electrolyte having oxygen ion permeability interposed therebetween. A plurality of single cells are provided, and a fuel gas flow path that faces the fuel electrode of each of the single cells to flow the fuel gas and an oxidation gas flow path that faces the air electrode to flow the oxidizing gas are isolated. In the solid oxide fuel cell hermetically sealed with a sealing material, the sealing material is a metal that becomes a semi-molten state at the operating temperature of the solid oxide fuel cell, and the plurality of single cells are connected in series or in parallel. It is also characterized in that it also serves as a current collecting member electrically connected to.

According to the present invention, the fuel gas passage formed so as to face each fuel electrode of the plurality of unit cells and the oxidizing gas passage formed so as to face each air electrode are isolated from each other. As the sealing material for sealing, a metal that is in a semi-molten state at the operating temperature of the solid oxide fuel cell is used, and the plurality of single cells are electrically connected in series or in parallel by the sealing material. Since the sealing material also serves as the connection current collecting member, it is not necessary to separately provide the connection current collecting member.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an embodiment of the solid oxide fuel cell of the present invention, which is a yttria-stabilized zirconia (YS) having oxygen ion permeability.
Z) is formed into a cylindrical shape having a predetermined size, and a porous air electrode 11a made of a perovskite-type lanthanum oxide is formed on the inner peripheral surface of the solid electrolyte 11a, and a fuel mainly containing nickel or the like is formed on the outer peripheral surface thereof. It is composed of a plurality of cylindrical single cells 11 formed by forming electrodes 11b.

That is, a plurality of unit cells 11 are arranged in parallel in a housing (not shown) whose two opposite sides are open so that the air electrodes 11b at both ends of each unit cell 11 are exposed. A metal seal material 13 which is housed and semi-molten at an open portion (one is omitted) of the housing so that fuel gas supplied to the inside of the housing does not leak outside at a battery operating temperature (about 1000 ° C.).
Seal airtightly with. Examples of the metal sealing material include copper / aluminum alloy.

Further, the insides of the tubular air electrodes 11b at both ends of each unit cell 11 communicate with the outside of the housing, and the other end of the current collector 12 has one end connected to the fuel electrode 11c on the outer periphery of each unit cell 11. The end is projected so as to be aligned with the one air electrode 11b projecting from the end of each unit cell 11. Then, the metal sealing material 13 is provided on the end of each current collector 12 and the air electrode 11 of the adjacent single cell 11.
b is integrally wrapped and electrically connected, each unit cell 11 is fixed in the housing, and the opening of the housing is hermetically sealed.

Next, the operation of this embodiment configured as described above will be described. When the fuel gas is supplied into the housing accommodating the plurality of unit cells 11 and air is circulated as the oxidizing gas in the air electrode 11b communicating with the outside of the housing of each unit cell 11, the porous air electrode 11b is obtained.
Oxygen gas in the air that has passed through turns into ions, passes through the solid electrolyte 11a, and reaches the fuel electrode 11c side. Then, the oxygen ions electrochemically react with hydrogen gas in the fuel gas flowing in contact with the porous fuel electrode 11c to generate an electromotive force in the single cell 11. The electric power generated in each unit cell 11 is connected to each current collector 12 and the air electrode 11b of the adjacent unit cell 11 in series by the metal seal material 13, so that the electric power of the housing end (not shown) is generated. It is taken out through the current collecting member.

The operating temperature of the fuel cell (about 10
At (00 ° C.), since the metal seal material 13 is heated to be in a semi-molten state, the difference in thermal expansion between the unit cells 11 and the housing is absorbed, damage to each member is prevented, and high sealing performance and The electrical connection state is maintained.

In this embodiment, the fuel electrode 1
The case where 1c is a solid oxide fuel cell including a plurality of single cells 11 formed on the outer periphery of the cylinder has been described. However, in the case of a solid oxide fuel cell including a single cell having a fuel electrode on the inner peripheral surface of the cylinder. However, it can be implemented in substantially the same manner.

In the above embodiment, the case of the cylindrical cell has been described, but the present invention can be applied to a fuel cell using a flat cell or a honeycomb cell.

[0019]

As is apparent from the above description, according to the present invention, the sealing material that hermetically seals between the fuel gas flow path and the oxidizing gas flow path is a metal, and this sealing material is a current collecting member. Since it also serves as a collector, it is not necessary to separately provide a current collecting member. Therefore, the connection work of the current collecting member, which has been conventionally required, becomes unnecessary, the productivity is improved, and the current collecting member does not project to the outside. Can be miniaturized.

[Brief description of drawings]

FIG. 1 is a sectional plan view of a stack showing an embodiment of a solid oxide fuel cell of the present invention.

FIG. 2 is a perspective view of a cylindrical single cell.

FIG. 3 is a cross-sectional plan view of a stack showing an example of a conventional solid oxide fuel cell.

FIG. 4 is a cross-sectional plan view of a stack showing another example of a conventional solid oxide fuel cell.

[Explanation of symbols]

11 ... Single cell, 11a ... Solid electrolyte, 11b ... Air electrode, 11c ... Fuel electrode, 12 ... Current collector, 13 ...
Metal seal material.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Satoru Yamaoka 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Ltd. (72) Inventor Mikiyuki Ono 1-1-5 Kiba, Koto-ku, Tokyo Shares Inside Fujikura

Claims (1)

[Claims] 1. A plurality of unit cells each having a fuel electrode formed on one side and an air electrode formed on the other side with a solid electrolyte having oxygen ion permeability interposed therebetween are provided, and the fuel electrode of each unit cell is provided. In the solid electrolyte fuel cell, the fuel gas passage for flowing the fuel gas and the oxidizing gas passage for flowing the oxidizing gas facing the air electrode are hermetically sealed with a sealing material so as to isolate the fuel gas passage from the air electrode. The sealing material is a metal that is in a semi-molten state at the operating temperature of the solid oxide fuel cell, and also functions as a current collecting member that electrically connects the plurality of unit cells in series or in parallel. Solid oxide fuel cell.