JP3200219B2 - Current collection structure of solid oxide fuel cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to a fuel cell using a solid electrolyte, relates to a current collecting structure of a fuel cell are electrically connected in particular single cell via an electrically 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) interposed therebetween. And a fuel electrode (cathode) mainly composed of nickel or the like, and an electromotive force is obtained by an electrochemical reaction between a fuel gas and air via a solid electrolyte. In this type of fuel cell, since it is necessary to separate the fuel gas flow path and the air flow path in an airtight state, conventionally, for example, a solid electrolyte is formed in a cylindrical shape, and the electrodes are formed on the inner and outer peripheral surfaces thereof. Provision is being made. In addition, since the power obtained by a single cell is small, conventionally, the required power is 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 constituted by 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. At the same time, the fuel electrode 4 is formed in a partially cut-out state on the outer peripheral surface of the solid electrolyte 2, and the interconnector 5 electrically connected to the air electrode 3 is protruded from the cut-out portion of the fuel electrode 4. . These single cells 1 are arranged in three rows 3 between a pair of current collector plates 7 and 8 made of, for example, nickel.
The unit cells 1 arranged in a matrix of rows and arranged in the vertical direction in FIG. 4 are arranged on the outer peripheral surface of the fuel electrode 4 of the unit cell 1 whose interconnector 5 is adjacent to the unit cell 1. The fuel cells 4 are electrically connected to each other via the conductive felt 6 in the unit cells 1 in each row arranged in the horizontal direction in FIG.

[0004] A current collecting plate 7 is electrically connected to the interconnector 5 of the three single cells 1 at the anode-side power take-out end of the module via a conductive felt 6. 3 which is the side power take-out end
A current collecting plate 8 is also electrically connected to the air electrode 3 of each single cell 1 via the conductive felt 6. Further, rod-shaped leads 9 and 10 made of, for example, nickel for extracting power are attached to the current collecting plates 7 and 8. The central part of each unit cell 1 serves as an air flow path, and the outer peripheral part of each unit cell 1 serves as a fuel gas flow path. Electric power can be extracted from the leads 9 and 10 via the electric plates 7 and 8.

[0005]

However, since the oxidation-reduction reaction between the fuel gas and the air via the solid electrolyte 2 in the module is performed at a temperature of about 1000 ° C., the conductive felt 6 becomes thin during power generation. bonded fibers are sintered to each other, electrically conductive felt 6 with shrinks to decrease its gap portion, disadvantageously the elasticity is lowered occurs. For this reason, the conductive felt 6
The contact state between the single cells 1 and between the single cells 1 and the current collector plates 7 and 8 deteriorates, and the electric resistance between them becomes large, so that sufficient power cannot be taken out from the leads 9 and 10. Occurs.

[0006] collector of the present invention has been made in view of the circumstances described above, the solid electrolyte fuel cell can be extracted sufficiently to the current collector means side via an electrically conductive felt the electromotive force generated in the unit cell It is intended to provide a structure .

[0007]

SUMMARY OF THE INVENTION The present invention, in order to achieve the above object, one or more single cell formed by sandwiching a solid electrolyte of a pair of electrodes, a pair of current collecting hand stage
Between the cells and between the single cells
In its contact <br/> the current collecting structure of the solid body electrolyte fuel cell of the unit cells and the current collection means are electrically connected via an electrically conductive felt, the current collector means electrically conductive For those who compress felt
Sandwiching always-on pre Symbol Single Cells and conductive felt countercurrent
A member for elastically pressing the current collecting means.
It is characterized in that there.

[0008]

According to the present invention, one or more single cells electrically connected between a pair of current collecting means via a conductive felt are constantly pressed from both sides by the elastically biased current collecting means. be conductive felt during power generation and sintering shrinkage, electrical of these unit cells and electric conductive felt is挾圧between collector means, the single cell and the current collecting means through the electrically conductive felt The connection is kept in good condition.

[0009]

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

That is, in this module, a plurality of single cells in which an air electrode 3 and a fuel electrode 4 are respectively formed on the inner and outer surfaces of a cylindrical solid electrolyte 2, and an interconnector 5 is provided to protrude from the air electrode 3. 1, the fuel electrodes 4 and the interconnector 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 the left and right The electrodes 4 are also electrically connected via the conductive felt 6. In addition, the interconnector 5 of the upper unit cell 1
And the current collecting plate 7 are electrically connected via the conductive felt 6, and the fuel electrode 4 of the lower unit cell 1 and the current collecting plate 8 are electrically connected via the conductive felt 6. The current collectors 7 and 8 are connected to rod-shaped leads 9 and 10 for extracting electric power.

When air flows into the air passage 11 at the center of each unit cell 1, oxygen gas passing through the air electrode 3 becomes oxygen ions, passes through the solid electrolyte 2 and passes through the fuel electrode 4
Side, and this electrochemically reacts with hydrogen gas in the fuel gas flowing in the fuel gas flow path on the outer peripheral side of each unit cell 1, and the air electrode 3 side of the unit cell 1 and the fuel electrode An electromotive force is generated on the four sides. Then, the electromotive force generated in each single cell 1 is collected by the pair of current collector plates 7 and 8 via the conductive felt 6, and is extracted to the outside by the leads 9 and 10.

The pair of current collectors 7 and 8 are movable together with the leads 9 and 10 toward the single cell 1, and the current collectors 7 and 8 are connected to the current collectors 7 and 8 and the solid state. It is always elastically urged toward the unit cell 1 at a predetermined pressure by an insulating compression spring 14 disposed between a fixed portion of the electrolyte fuel cell, for example, a cell case 13 covering the module.
It should be noted that the compression spring 14 operates at the temperature of the single cell 1 during power generation (approximately 10
(00 ° C.) because it is necessary to sufficiently withstand the strength and to generate the necessary spring force. Therefore, it is made of a material having excellent heat resistance such as nickel, nickel cermet or ceramics. When formed from a material, an insulating material is interposed between the compression spring 14 and the current collector plates 7 and 8.

Therefore, the conductive felt 6 sinters during power generation, thereby shrinking and reducing elasticity.
Even if the electrical connection between the single cells 1 and the current collecting plates 7 and 8 is insufficient, the single cells 1 positioned vertically
The current collectors 7, which are elastically biased by the compression springs 14,
8, the conductive felt 6 between the single cells 1 and between the single cell 1 and the current collectors 7 and 8 is compressed and adhered to each other, and the single cell 1 is pressed via the conductive felt 6.
Each other and the single cell 1 and the current collector plates 7 and 8 are electrically connected in a sufficiently favorable state. Therefore, even if sintering occurs in the conductive felt 6, the electromotive force generated in the single cell 1 can be sufficiently extracted to the current collector plates 7 and 8 through the conductive felt 6.

In the above embodiment, both the current collectors 7 and 8 are pressed toward the single cell 1 by the compression springs 14. For example, one current collector 7 is fixed and the other current collector 8 is pressed. Only the single cell 1 may be pressed by the compression spring 14.

The pressing of the current collector plates 7 and 8 toward the single cell 1 is not limited to the compression spring. For example, one end of an insulating piston pressurized by a fluid in a cylinder is applied to the current collector plates 7 and 8. After being mounted, the pistons may elastically urge the current collector plates 7 and 8 toward the single cell 1 at a predetermined pressure.

Further, the solid oxide fuel cell of interest is not only a module in which the single cells 1 are connected in series and parallel, but also
A stack (in this case, having a plurality of stacks) in which the single cells 1 are connected in series as shown in FIG.
May be connected in parallel.

[0017]

As is apparent from the above description, according to the present invention , the conductive felt loses its elasticity due to sintering.
Or shrink, but in a direction to compress the conductive felt
Current collector elastically sandwiches single cell and conductive felt
Good contact condition via conductive felt
As a result, the electromotive force generated in the single cell can be stably taken out to the current collector through the conductive felt.

[Brief description of the drawings]

FIG. 1 is a sectional view of a solid oxide fuel cell module showing one 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 ... current collecting plate (current collecting means), 8 ... current collecting plate (current collecting means), 13 ... cell case, 14 ... compression spring.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takenori Nakajima 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (56) References JP-A-3-8266 (JP, A) JP-A-61- 218074 (JP, A) JP-A-3-171562 (JP, A) JP-A-63-162458 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 8/02 H01M 8 / 12 H01M 8/24

Claims (1)

(57) [Claims] 1. A solid one or more single cell an electrolyte is formed sandwiched by a pair of electrodes, the pair of collector hand stage
Placed between them and between those single cells or
A current collecting structure of the solid body electrolyte fuel cell of the unit cells and the current collection means are electrically connected via an electrically conductive felt Te at <br/>, the current collector means electrically conductive felt the pre <br/> Symbol single cells and conductive felt in a direction to compress as give always-on clamp the
And a member for elastically pressing the current collecting means .