JPH06203857A - Method for collecting current in solid electrolyte fuel cell - Google Patents

Abstract

PURPOSE:To provide a method for collecting current in a solid electrolyte fuel cell, whereby a sufficient amount of electromotive force generated by cells can be taken out to current collection means via conductive felt. CONSTITUTION:One or two (or more) cells 1, disposed between and electricaly connected to a pair of current collection means 7, 8 via conductive felt 6, are pressed by the current collection means 7,8. Since the current collection means 7, 8 are resiliently pressed by compression springs 14 to press the conductive felt 6 and the cells 1, even if contraction, etc., of the conductive felt 6 occurs due to sintering at power generation the current collecting plates 7, 8 and the cells 1 are held in good electrical connection with one another, so that a sufficient amount of electromotive force generated by the cells 1 can be taken out to the current collection means 7, 8 via the conductive felt 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell using a solid electrolyte, and more particularly to a fuel cell current collecting method in which single cells are electrically connected through a conductive felt.

[0002]

2. Description of the Related Art A solid oxide fuel cell is an air electrode (anode) made of, for example, a perovskite-type lanthanum-based composite oxide with a solid electrolyte such as yttria-stabilized zirconia (YSZ) or calcia-stabilized zirconia (CSZ) sandwiched therebetween. And a fuel electrode (cathode) mainly composed of nickel and the like are provided, and an electromotive force is obtained by an electrochemical reaction between the fuel gas and air through the solid electrolyte. In this type of fuel cell, it is necessary to separate the fuel gas flow path and the air flow path in an airtight state. Therefore, conventionally, for example, a solid electrolyte is formed in a cylindrical shape, and the electrodes are formed on the inner peripheral surface and the outer peripheral surface thereof. It is being provided. In addition, since the power obtained by a single cell is low, the required power can be conventionally reduced by connecting a plurality of single cells in series to form a stack or by connecting a plurality of single cells in series and parallel to form a module. It has gained.

FIG. 4 is a sectional view of a module composed of nine cylindrical single cells 1. Each single cell 1 shown here has an air electrode 3 formed on the inner peripheral surface of a cylindrical solid electrolyte 2. In addition, the fuel electrode 4 is formed in a partially cutout state on the outer peripheral surface of the solid electrolyte 2, and the interconnector 5 that is electrically connected to the air electrode 3 is provided so as to project from the cutout portion of the fuel electrode 4. . These unit cells 1 are arranged in three rows 3 between a pair of collector plates 7 and 8 made of nickel, for example.
The unit cells 1 arranged in a matrix of rows and arranged in the vertical direction in FIG. 4 have a conductive structure made of, for example, nickel on the outer peripheral surface of the fuel electrode 4 of the unit cell 1 to which the interconnector 5 is adjacent. 3 are electrically connected via the conductive felt 6, and the fuel cells 4 of the unit cells 1 in each row arranged in the left-right direction in FIG. 3 are electrically connected via the conductive felt 6.

A collector plate 7 is electrically connected to the interconnectors 5 of the three unit cells 1 which are the anode side power extraction ends of this module through a conductive felt 6, and the cathode of this module is 3 which is the end of the side power extraction
A current collector plate 8 is electrically connected to the air electrode 3 of each single cell 1 through the conductive felt 6. Further, rod-shaped leads 9 and 10 made of, for example, nickel for extracting electric power are attached to the current collector plates 7 and 8. The central portion of each single cell 1 serves as an air flow passage, and the outer peripheral portion of each single cell 1 serves as a fuel gas flow passage. Electric power can be taken out from the leads 9 and 10 via the electric plates 7 and 8.

[0005]

However, since the redox reaction between the fuel gas and the air via the solid electrolyte 2 in the module is carried out at a temperature of about 1000 ° C., the conductive felt 6 is thin during power generation. The fibers are sintered and bonded to each other, the voids of the conductive felt 6 are reduced and the conductive felt 6 contracts, and the elasticity of the conductive felt 6 decreases. Therefore, the conductive felt 6
The contact state between the unit cells 1 connected to each other and between the unit cells 1 and the current collecting plates 7 and 8 is deteriorated, and the electric resistance between them becomes large, so that sufficient power cannot be extracted from the leads 9 and 10. Occurs.

The present invention has been made in view of the above circumstances, and a collector of a solid oxide fuel cell capable of sufficiently extracting the electromotive force generated in a single cell to the collector means side through a conductive felt. It is intended to provide a method.

[0007]

In order to achieve the above-mentioned object, the present invention has one or more unit cells formed by sandwiching a solid electrolyte between a pair of electrodes. In a current collecting method for a solid oxide fuel cell arranged in a state of being electrically connected via a conductive felt, the current collecting means is elastic so as to constantly press the single cell and the conductive felt. It is characterized by being biased.

[0008]

Since one or more unit cells electrically connected between the pair of current collecting means through the conductive felt are constantly pressed from both sides by the elastically biased current collecting means, Even if the conductive felt sinters and contracts during power generation,
These unit cells and conductive felts are pressed between the current collecting means, and the electrical connection with the unit cells and current collecting means through the conductive felts is maintained in a good state.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view of a module of a solid oxide fuel cell according to an embodiment of the present invention, and the basic configuration of this module is almost the same as the module shown in FIG.

That is, in this module, the air electrode 3 and the fuel electrode 4 are formed on the inner and outer surfaces of the cylindrical solid electrolyte 2, respectively, and the interconnector 5 is provided so as to project from the air electrode 3. 1, the fuel electrodes 4 and the interconnectors 5 of the unit cells 1 vertically adjacent to each other in FIG. 1 are electrically connected via the conductive felt 6, and the fuel of the unit cells 1 adjacent to each other in the left and right direction is also provided. The electrodes 4 are also electrically connected to each other via the conductive felt 6. In addition, the interconnector 5 of the upper single cell 1
And the current collector plate 7 are electrically connected via the conductive felt 6, and the fuel electrode 4 of the lower unit cell 1 and the current collector plate 8 are electrically connected via the conductive felt 6. In addition, rod-shaped leads 9 and 10 for taking out electric power are connected to these collector plates 7 and 8.

When air is passed through the air flow path 11 on the central side of each unit cell 1, the oxygen gas passing through the air electrode 3 becomes oxygen ions and passes through the solid electrolyte 2 to pass through the fuel electrode 4
Of the single cell 1 and the hydrogen gas in the fuel gas flowing in the fuel gas flow path on the outer peripheral side of each unit cell 1 electrochemically react with each other, and the air electrode 3 side of the unit cell 1 and the fuel electrode Electromotive force is generated on the 4 side. The electromotive force generated in each unit cell 1 is collected by the pair of collector plates 7 and 8 through the conductive felt 6 and taken out by the leads 9 and 10.

The pair of current collecting plates 7 and 8 are movable together with the leads 9 and 10 toward the unit cell 1 side, and the current collecting plates 7 and 8 are solid and solid. An insulating compression spring 14 arranged between a fixed portion of the electrolyte fuel cell, for example, a cell case 13 covering the module, is constantly elastically biased toward the unit cell 1 side with a predetermined pressure.
It should be noted that the compression spring 14 has a temperature (about 10
It is made of a material with excellent heat resistance, such as nickel, nickel cermet or ceramics, because it is necessary to sufficiently withstand the temperature (00 ° C) and generate the required spring force. When it is made of a material, an insulating material is interposed between the compression spring 14 and the current collector plates 7 and 8.

Therefore, when the conductive felt 6 is sintered during power generation, the conductive felt 6 contracts and becomes less elastic, so that the unit cell 1
Between the unit cells 1 and the current collectors 7 and 8 even if the electrical connection between the unit cells 1 and the current collector plates 7 and 8 becomes insufficient, the unit cells 1 are positioned vertically.
The collector plates 7, which are elastically biased by the compression spring 14,
Since it is pressed with a predetermined pressure by 8, the conductive felts 6 between the single cells 1 and between the single cells 1 and the current collecting plates 7 and 8 are compressed and adhered to each other.
The single cells 1 and the current collecting plates 7 and 8 are electrically connected to each other in a sufficiently good condition. Therefore, even if the conductive felt 6 is sintered, the electromotive force generated in the unit cell 1 can be sufficiently taken out to the current collector plates 7 and 8 side through the conductive felt 6.

In the above embodiment, both the current collecting plates 7 and 8 are pressed to the unit cell 1 side by the compression spring 14. However, for example, one current collecting plate 7 is fixed and the other current collecting plate 8 is fixed. Only the unit cell 1 may be pressed by the compression spring 14.

Further, the pressing of the current collector plates 7, 8 toward the unit cell 1 side is not limited to the compression spring, and for example, one end of an insulating piston pressurized by the fluid in the cylinder is applied to the current collector plates 7, 8. Alternatively, the pistons may be attached so that the current collector plates 7 and 8 are elastically biased toward the unit cell 1 by a predetermined pressure.

Further, the target solid oxide fuel cell is not only a module in which the unit cells 1 are connected in series and parallel,
A stack in which the unit cells 1 as shown in FIG. 2 are connected in series (in this case, a plurality of stacks are provided), and FIG.
The single cells 1 as shown by may be connected in parallel.

[0017]

As is apparent from the above description, according to the present invention, one or more unit cells formed by sandwiching a solid electrolyte between a pair of electrodes are electrically conductive between a pair of current collecting means. In a current collecting method of a solid oxide fuel cell arranged in a state of being electrically connected via a felt, a current collecting circuit in which a unit cell and a conductive felt between the current collecting means are elastically biased. Since the conductive felt is pressed by the means, even if the conductive felt sinters and shrinks, the current collecting means and the unit cell are always electrically connected in a good state through the conductive felt. The electromotive force generated in the cell can be stably taken out to the current collector side via the conductive felt.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a solid oxide fuel cell stack showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view around a single cell of a solid oxide fuel cell showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional solid oxide fuel cell module.

[Explanation of symbols]

1 ... Single cell, 2 ... Solid electrolyte, 3 ... Air electrode, 4
... fuel electrode, 6 ... conductive felt, 7 ... collector (collector), 8 ... collector (collector), 13 ... cell case, 14 ... compression spring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takenori Nakajima 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Ltd.

Claims (1)

[Claims] 1. One or more unit cells formed by sandwiching a solid electrolyte between a pair of electrodes are arranged in a state of being electrically connected between a pair of current collecting means via a conductive felt. In the current collecting method of a solid oxide fuel cell, the current collecting means is elastically biased so as to constantly press the single cell and the conductive felt. Collection method.