JP3048689B2 - Structure of solid oxide fuel cell module - Google Patents

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 module structure in which a plurality of cylindrical single cells are combined.

[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 oxidation-reduction reaction between a fuel gas and air via a solid electrolyte. In this type of fuel cell, it is necessary to separate the fuel gas flow path and the air flow path from each other in an airtight state. Therefore, it is preferable to form the solid electrolyte into a cylindrical shape and provide the electrodes on the inner and outer peripheral surfaces thereof. . Further, since the power obtained by a single cell is small, conventionally, a plurality of single cells are connected in series and parallel to form a module, and a plurality of these are used to obtain required power.

FIG. 3 is a sectional view of a module constituted by six 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 close contact with the outer periphery of the anode-side current collector 6, and each of the interconnectors 5 is electrically connected to a conductive felt 7 provided on the outer peripheral surface of the anode-side current collector 6. In contact. Further, the whole of these is accommodated in a cylindrical cathode current collector 8, and the fuel electrode 4 of each unit cell 1 is electrically connected to a conductive felt 9 provided on the inner peripheral surface of the cathode current collector 8. Contacting state. The central portion of each unit cell 1 serves as an air passage 10, and the outer peripheral portion of each unit cell 1 serves as a fuel gas passage 11 such as hydrogen gas.

The module shown in FIG. 4 is configured by arranging nine single cells 1 in a matrix of three columns and three rows between a pair of current collectors 12 and 13. In each unit cell 1 arranged in the vertical direction, the interconnector 5 is electrically connected to the outer peripheral surface of the fuel electrode 4 of the adjacent unit cell 1 via a conductive felt 14, and furthermore, the horizontal direction in FIG. The single cells 1 in each row arranged in the direction electrically connect the fuel electrodes 4 to each other via the conductive felt 14.

[0005]

Therefore, in the module shown in FIG. 3, electric power can be extracted from the current collectors 6, 8 by flowing air or fuel gas through the flow paths 10, 11, and FIG. In the module shown in FIG.
Power can be obtained using the upper current collector 12 as an anode and the lower current collector 13 as a cathode. The output thus obtained is the sum of the outputs of each single cell 1,
Since the power generation efficiency varies depending on the temperature, the supply state of air or fuel gas to the surface of the solid electrolyte 2, the degree of deterioration of the solid electrolyte 2, etc., it is necessary to manage each unit cell 1 in order to increase the output of each module. . However, in the above-described conventional module, only the output as a whole can be known, so that even when the power generation efficiency of any single cell is poor, air or fuel gas flows evenly through each single cell. Energy efficiency may be reduced,
In addition, when the output of the entire module is reduced due to poor power generation efficiency of any single cell, the entire module has to be replaced, resulting in an increase in maintenance cost.

The present invention has been made in view of the above circumstances, and has as its object to provide a structure of a fuel cell module capable of knowing the output state of each unit cell constituting the module. .

[0007]

According to the present invention, in order to achieve the above object, one of an air electrode and a fuel electrode is formed on an inner peripheral surface of a cylindrical solid electrolyte, and the other is formed on the other side. Electrodes are formed on the outer peripheral surface of the solid electrolyte,
In the structure of a solid oxide fuel cell module comprising a plurality of single cells provided with an interconnector which is electrically connected to the inner electrode and not electrically connected to the outer electrode, and is provided so as to protrude outward in the radial direction. Providing, for each single cell, a current collector electrically connected only to the interconnector or the outer electrode, bringing the current collector into contact with an insulating holder common to a plurality of single cells, and Are drawn out so as to be electrically connectable to one axial end of each unit cell.

[0008]

In the single cell constituting the module of the present invention, one of the air and the fuel gas flows in the center portion and the other flows on the outer peripheral side, whereby an oxidation-reduction reaction occurs through the solid electrolyte to generate an electromotive force. Is generated. One electrode of each single cell is electrically connected to a current collector provided individually corresponding to each electrode, and the current collectors are held in contact with an insulating holder. Therefore, since each current collector corresponds to each single cell, power can be taken out for each single cell via those current collectors, whereby the operating state of the single cell can be known. In addition, if each current collector is put together at one end of the single cell, it becomes one electrode of the whole module.

[0009]

FIG. 1 is a sectional view showing an embodiment of the present invention. A fuel cell module 20 shown in FIG. 1 is composed of six single cells 21. Have been. The unit cell 21 has substantially the same structure as a conventional unit cell, and its sectional shape is as shown in FIG. That is, calcia stabilized zirconia (C
An air electrode 23 is formed on the entire outer peripheral surface of a support tube 22 which is a porous tube made of SZ), alumina (Al203) or the like, and a solid electrolyte 24 is formed in a partially notched state on the outer periphery. The fuel electrode 25 is formed in a partially cut-out state on the outer periphery. An interconnector 26 is formed in a partially cutout portion of the solid electrolyte 24 so as to straddle both ends thereof.

The six single cells 21 are arranged in close contact with each other around a center support tube 27 such that the respective interconnectors 26 face the center. The center support tube 27 is made of an insulating material, for example, made of alumina.
One and the same number of ridges are formed along the axial direction, and a current collector 28 made of nickel (Ni) felt and a Ni rod is arranged between the ridges. The corresponding current collector 28 is in electrical conduction. Each current collector 28 extends to one end in the axial direction of the unit cell 21 so that a lead wire or the like (not shown) can be connected thereto.

As described above, the six single cells 21 equally arranged around the center support tube 27 are accommodated in the conductive pipe 29 in that state. The conductive pipe 29 is made of, for example, Ni or Ni and ZrO2, and the fuel electrode 25 of each unit cell 21 is made of Ni felt 30.
And is electrically connected to the inner peripheral side of the conductive pipe 29 via the.

The center of each unit cell 21 is located in the air passage 3
1 and the hollow portion on the outer peripheral side of each unit cell 21 is a fuel gas flow path 32 for hydrogen gas or the like. Therefore, the module 20 shown in FIG. 1 operates using each current collector 28 as an anode and the conductive pipe 29 as a cathode.

That is, when air is supplied to the air flow path 31 and hydrogen gas is supplied to the fuel gas flow path 32, an oxidation-reduction reaction occurs through the solid electrolyte 24. In this case, oxygen ions move the solid electrolyte 24 from the air electrode 23 side to the fuel electrode 25 side.
Is an anode, and the fuel electrode 25 is a cathode. Therefore, as a whole of the module 20, each current collector 28 is an anode and the conductive pipe 29 is a cathode. Since the current collector 28 serving as the anode is independent for each single cell 21, if the current collectors 28 are combined into one, the current collector 28 serves as the anode in the module 20 while one current collector 28 is used. If they are separately divided, they can be output for each single cell 21. In other words, in the module shown in FIG. 1, the electromotive force of each single cell 21 can be known, and the energy efficiency can be increased by adjusting the air supply amount of each single cell 21 based on the measurement result. In addition, pass / fail can be determined for each single cell 21.

In the above-described embodiment, the current collector 28 connected to the interconnector 26 is provided. However, the present invention is not limited to the above-described embodiment.
For 5, an independent current collector may be provided for each single cell. Further, the present invention is not limited to a cylindrical module, and can be applied to a module in which single cells are arranged in a matrix.

[0015]

As explained above, according to the present invention,
Since it is possible to know the electromotive force and operating status of each single cell that constitutes the module, it is possible to manage the air supply amount and replacement time for each single cell, resulting in efficient power generation. In addition, the management and maintenance cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view of the single cell.

FIG. 3 is a sectional view of a conventional cylindrical module.

FIG. 4 is a cross-sectional view of a conventional module in which single cells are arranged in a matrix.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 20 ... Module, 21 ... Single cell, 23 ... Air electrode, 24 ... Solid electrolyte, 25 ... Fuel electrode, 26 ... Interconnector, 27 ... Center side support tube, 28 ... Current collector.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takenori Nakajima 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (56) References JP-A-2-312165 (JP, A) JP-A-61 -259462 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 8/00-8/24

Claims (1)

(57) [Claims] 1. An air electrode or a fuel electrode is formed on an inner peripheral surface of a cylindrical solid electrolyte, and
The other electrode is formed on the outer peripheral surface of the solid electrolyte, and a plurality of interconnectors are provided projecting radially outward from the inner peripheral electrode and not interconnecting the outer peripheral electrode. In the structure of a solid oxide fuel cell module composed of single cells, a current collector that is conducted only to the interconnector or the outer electrode is provided for each single cell, and the current collector is shared by a plurality of single cells. A structure of a solid oxide fuel cell module, wherein each solid collector is brought into contact with an insulating holder, and each current collector is drawn out so as to be electrically connectable to one axial end of each unit cell.