JP2000182642A - Solid oxide fuel cell module - Google Patents

Abstract

(57) [Problem] To provide a fuel cell module which is inexpensive and can be used for a long time using an interconnectless fuel cell. SOLUTION: A solid oxide fuel cell 10 without an interconnector is arranged in a matrix to form one assembly 12, and a plurality of assemblies are accommodated in one power generation chamber 11. The electric charge generated at the air electrode 103 of each of the solid oxide fuel cells belonging to each assembly by the power generation action is transferred to the upper air electrode side current collector plate 33 by the air electrode side current collector 34 arranged between the air electrode 103 itself and the air electrode. The electric charge generated at the fuel electrode 101 of each of the solid oxide fuel cells belonging to each assembly is collected by a common fuel electrode side current collector plate 39.
DC power is obtained by connecting all fuel cell assemblies in series.
A LaCrOx-based oxide layer 111 is formed at the upper end of the air electrode 103,
This portion is configured to be in contact with the air electrode side current collector plate 33 to enhance durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid oxide fuel cell module using an interconnect-less solid oxide fuel cell.

[0002]

2. Description of the Related Art In recent years, solid oxide fuel cells (SOF)
The development of a solid oxide fuel cell module applicable to the practical device of C) is underway. JP-A-10-01225
No. 8 proposes an internal reforming solid oxide fuel cell module. In this conventional solid oxide fuel cell module, a reforming reaction between fuel gas and steam is performed in the module without providing an external reforming reactor, and then the fuel gas is supplied to the fuel cell stack and used for power generation. It is assumed that.

In this conventional solid oxide fuel cell module, a vertical stripe solid oxide fuel cell having an interconnector 1 as shown in FIG. 11 is used for each solid oxide fuel cell. The vertical stripe type solid electrolyte fuel cell having the interconnector 1 has a porous substrate tube 2
The air electrode 3, the solid electrolyte 4, and the fuel electrode 5
The interconnector 1 is laminated by the VD method or another method and is embedded in a form insulated from the fuel electrode 5 for series connection with an adjacent solid oxide fuel cell. It is the structure connected to.

[0004]

However, in the case of a solid oxide fuel cell module employing a solid oxide fuel cell having such an interconnect, a boundary portion between the fuel electrode 5, the solid electrolyte 4 and the interconnect 1 is required. There is a difference in the material, especially the fuel cell module 800 ~
Since power is generated under a high temperature condition of 1000 ° C., there is a problem that breakage easily occurs due to a difference in thermal expansion coefficient.

[0005] To cope with this, a technology for constructing a fuel cell module using an interconnect-less solid oxide fuel cell is being developed. However, in the case of an interconnect-less solid oxide fuel cell, a fuel cell assembly is used. In order to electrically connect fuel cells adjacent to each other, a technique that replaces the conventional interconnector is required.

SUMMARY OF THE INVENTION The present invention has been made to solve such a technical problem, and is directed to a solid electrolyte module using an interconnect-less solid electrolyte fuel cell, which can be operated for a long time. It is an object of the present invention to provide a solid oxide fuel cell module capable of extracting generated power with high efficiency and reducing manufacturing costs.

[0007]

According to a first aspect of the present invention, an air electrode, a solid electrolyte, and a fuel electrode are laminated in order from the outside to the inside, and a fuel supply pipe for both current collection and insertion is inserted inside the fuel electrode. A predetermined number of interconnect-less solid oxide fuel cells are arranged in a matrix to form one assembly, a plurality of assemblies are accommodated in a power generation chamber, and a fuel discharge chamber and a fuel supply chamber are formed above the power generation chamber. , The entirety of which is surrounded by a heat insulating material, and in each of the assemblies, each of the air electrodes is brought into common and electrical contact with the air electrode-side current collector, and each of the fuel supply pipes is made common with the fuel electrode-side current collector. A solid oxide fuel cell module having an electrically connected structure, a LaCrOx-based oxide layer is formed on a surface of a contact portion of each of the air electrodes with the air electrode-side current collector plate, and the protective layer is Air electrode side current collection It is obtained by contacting the.

In the solid oxide fuel cell module according to the first aspect of the present invention, a predetermined number of interconnect-less solid oxide fuel cells are arranged in a matrix to form one assembly, and a plurality of assemblies are arranged in one power generation chamber. It is housed and generates electricity by each. The charge generated in the air electrode of each solid oxide fuel cell belonging to the assembly by the power generation of each assembly is collected by the air electrode side current collector,
The electric charge generated at the fuel electrode of each of the solid oxide fuel cells belonging to the assembly is collected by the fuel electrode side current collector.

According to a second aspect of the present invention, in the solid oxide fuel cell module of the first aspect, a nickel layer is further formed on the surface of the LaCrOx-based oxide layer, and the nickel layer is formed on the air electrode side current collector plate. The electric contact between the air electrode and the air electrode side current collector is improved, and the current collection efficiency is increased.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a structural view of one embodiment of the present invention. A solid oxide fuel cell module according to this embodiment includes a solid electrolyte fuel cell 10 in a power generation chamber 11.
A fuel cell assembly 12 in which a plurality of fuel cells 10 are arranged in a matrix in this case,
A fuel supply chamber 13 for supplying natural gas and steam as fuel gas 22 to the fuel cell 10 of the power generation chamber 11, and a fuel discharge chamber for discharging fuel exhaust gas and unreacted gas generated by the fuel cell reaction to the outside as discharged fuel 25. 14 and power generation room 1
A heat exchanger 17 for exchanging heat between the air 24 supplied to 1 and the exhaust air 26 is provided, and these are surrounded by a heat insulating material 19.

As a solid oxide fuel cell 10, FIG.
Use the one without interconnector shown in (1). The solid oxide fuel cell 10 has a fuel electrode 10
1. A solid electrolyte 102 and an air electrode 103 are formed, and a current collector / fuel supply pipe 104 made porous for fuel ejection is inserted into the center thereof.
Is filled with a conductive felt 105 having a fuel reforming function. The fuel gas 22 is supplied to the fuel supply pipe 104 under a high temperature condition of 800 to 1000 ° C., and the air 24 flows around the outer periphery. This causes a power generation reaction.

The natural gas and steam supplied as the fuel gas 22 may have been subjected to a reforming treatment before being introduced into the module in the same manner as in the prior art, and Japanese Patent Application Laid-Open No. 10-012258. As described in (1), a pre-reformer may be provided at the upper end of the fuel supply pipe 104 that also serves as a current collector, and a reforming process may be performed here. There is no particular limitation.

The upper end of the air electrode 103, which is the outermost shell of each of the solid oxide fuel cells 10 belonging to each assembly 12, is fixed and supported by an insulating partition member 31 that separates the power generation chamber 11 and the fuel discharge chamber 14. The upper end of the fuel supply pipe 104 of each solid oxide fuel cell 10 has an insulating partition member 3 that separates the fuel discharge chamber 14 from the fuel supply chamber 13.
2 fixed and supported.

As shown in detail in FIG. 3, the upper end of each solid oxide fuel cell 10 is supported by an insulating partition member 31 for partitioning between the power generation chamber 11 and the fuel discharge chamber 14. 31 is electrically connected to the stacked air electrode side current collector plate 33 on the fuel discharge chamber 14 side. The exposed portion of the air electrode 103 at the upper end of the solid oxide fuel cell 10 toward the fuel discharge chamber 14 side includes:
The LaCrOx-based oxide layer 111 is coated and sealed, and nickel (N) is used to improve the electrical contact between the LaCrOx-based oxide layer 111 and the cathode-side current collector 33.
i) A layer 112 is formed, and the Ni layer 112 is brought into contact with the air electrode side current collector 33. The portion of the Ni layer 112 is joined and fixed to the cathode-side current collecting plate 33 by the nickel paste 113. This LaCrO
The x-based oxide layer 111 is formed by, for example, a plasma spraying method.

As shown in detail in FIG. 4, in each fuel cell assembly 12 in the power generation chamber 11, an air electrode side current collecting member 34 also serving as a spacer is provided between adjacent solid oxide fuel cells 10. Are located. As shown in FIG. 5, this air electrode side current collecting member 34 is made of SUS or Ni-C
An r-based alloy is used as the base material 34A, and LaCrO
This is a structure in which an x-based oxide coating layer 34B is formed. Then, in order to reduce the contact resistance with each air electrode 103, a platinum paste 35 is interposed on the contact surface between them.

As shown in detail in FIGS. 5 and 6, a current collecting end 3 is provided at the upper end of the air electrode side current collecting member 34.
6 are provided. This current collecting end 36 is electrically connected to the air electrode side current collecting plate 33 provided on the upper surface side of the insulating partition member 31. The structure of this connection portion will be described with reference to FIG. 5. A nickel layer 37 for further improving conductivity is provided on the surface of the current collecting end portion 36 on which the LaCrOx-based oxide coating layer 34B is formed.
The air electrode side current collector 33 is brought into contact with the nickel layer 37, and the two are joined and fixed by a nickel paste 38.

As shown in FIGS. 1 and 7, the fuel supply chamber 1
Insulating partition member 3 for partitioning the fuel discharge chamber 3 from the fuel discharge chamber 14
A fuel electrode side current collector plate 39 is provided on the lower surface side of the fuel cell 2, that is, on the side facing the fuel discharge chamber 14, and the upper end of the fuel supply pipe 104 of each fuel cell 10 belonging to each fuel cell assembly 12. Are connected in common. Therefore, in each fuel cell assembly 12, the air electrode side current collector 33 and the fuel electrode side current collector 39 face up and down in the same fuel discharge chamber 14. When the solid oxide fuel cell module shown in FIG. 1 is composed of four assemblies 12 as shown in FIGS. 6 and 7, as shown in an equivalent electric circuit in FIG. Of the air electrode side current collector plate 1+ and the second
And the anode-side current collector plate of each assembly is connected in series with the anode-side current collector plate of an adjacent assembly in the same manner. Finally, the four assemblies are connected in series. Output terminals 41 and 42 for extracting electric power to the outside are respectively provided on the fuel electrode side current collector 1- of the first assembly and the air electrode side current collector 4+ of the fourth assembly which are located at the end positions of the series connection. Connected.

Next, the operation of the solid oxide fuel cell module having the above configuration will be described. The fuel gas 22 is supplied to the fuel supply chamber 13 and supplied from each of the fuel supply pipes 104 into each of the solid oxide fuel cells 10, or after being reformed by the pre-reformer at the upper end of the fuel supply pipe 104, 104 each solid oxide fuel cell 1
It is supplied within 0 and used for power generation. Then, after being used for power generation, it is collected in the fuel discharge chamber 14 and exhausted outside the system as exhaust fuel 25.

On the other hand, the air 24 performs regenerative heat exchange with the exhaust air 26 by an air heat exchanger 17 provided at the lower part of the module, and is preheated before being supplied to the power generation chamber 11. Here, the air 24 is used for power generation in the power generation chamber 11,
Thereafter, the discharged air 26 heated to 800 to 1000 ° C.
Is collected in the air discharge pipe 18 and sent to the heat exchanger 17,
Here, after heat exchange, the air is exhausted to the outside.

The negative charge generated on the air electrode 103 side of each solid oxide fuel cell 10 by the power generation action of the solid oxide fuel cell module is converted to the air electrode side current collecting member 34.
The air electrode 103 itself also derives a negative charge to the upper air electrode side current collector 33 due to its conductivity, and the air electrode 103 itself assembles by the air electrode side current collector 33. Collect power every 12 minutes. In parallel with this, the negative charges generated on the fuel electrode 101 side are led out to the fuel electrode side current collector 39 on the upper side by the fuel supply pipe 104, and the current is collected for each assembly 12 here. And
All the collected electric charges flow as DC through the four assemblies 12 connected in series, and finally output terminals 41 and 4.
2 is taken out as DC power.

Here, assuming that the electromotive voltage V and the current I of each solid oxide fuel cell 10 alone are, four fuel cells 10 are connected in parallel in each assembly 12 unit.
An electromotive voltage V and a current 4I, the four assemblies 12
Are connected in series so that the final output is obtained.
V and current 4I.

Thus, in the solid oxide fuel cell module of this embodiment, a plurality of solid oxide fuel cells are arranged in a matrix to form one assembly 12, and a plurality of assemblies constitute one module. In each assembly, an air electrode side current collecting member 34 also serving as a spacer is arranged between adjacent opposing fuel cell rows to make electrical contact with each air electrode 103, and the upper end current collecting end 36 is connected to the air electrode 103. At the same time, the upper end of the air electrode 103 on the outer periphery of each fuel cell 10 is also connected to the air electrode side current collector 33, and in parallel with this, the fuel supply pipes 104 in each assembly are respectively connected. Are connected in parallel by the fuel electrode side current collector plate 39, and are connected in series between the assemblies 12 by the connection wires 40. Even when a solid oxide fuel cell is used, high-voltage, low-current DC power can be extracted, and a fuel cell without an interconnector can be used. It is less susceptible to damage due to the difference between the two, and long-term continuous operation is possible.

Further, in the solid oxide fuel cell module of this embodiment, a LaCrOx-based oxide layer 111 is formed on the surface of the air electrode 103 at the upper end of each fuel cell 10, and the LaCrOx-based oxide layer 111 is further formed. Has a structure in which a nickel layer 112 having high conductivity is formed on the surface thereof and this nickel layer 112 is bonded to the air electrode side current collector plate 33, so that the nickel layer 112 has durability against power generation under high temperature conditions. To enable long-term use.

In the above embodiment, one assembly 12 is constituted by the four solid oxide fuel cells 10 and one module is constituted by the four assemblies 12. However, these values are not particularly limited. The number of assemblies connected in series can be increased as much as possible, especially in order to obtain large power.

Further, the structure of the air electrode side current collecting member 34 is not limited to the above-described embodiment, and a structure shown in FIG. 9 or FIG. 10 can be used. The air electrode side current collecting member 34 shown in FIG.
LaCrOx-based oxide or LaMnOx is applied to the entire surface of the Cr-based alloy base material 34A (including the entire surface of the current collecting end 36).
Forming a coating layer 34B of a system oxide;
6 has a structure in which a nickel layer 37 is coated on the entire surface of a coating layer 34B, and this is joined to a current collector 33 by a nickel paste 38. The structure shown in FIG.
A LaMnOx-based oxide coating layer 34B1 is formed almost entirely on the surface of the base material 34A of the S or Ni—Cr-based alloy except for the current collecting end portion 36, and the surface corresponding to the current collecting end portion 36 is formed on the surface. Forms a LaCrOx-based oxide coating layer 34B2, forms a nickel layer 37 on the surface of the LaCrOx-based oxide coating layer 34B2 in the same manner as in the above embodiment, and forms the nickel layer 37 on the air electrode side. In this structure, the current collector 33 is brought into contact with the current collector 33, and the two are fixed with a nickel paste 38.

[0026]

As described above, according to the first aspect of the present invention,
A predetermined number of interconnect-less solid oxide fuel cells are arranged in a matrix to form one assembly, a plurality of assemblies are accommodated in one power generation chamber, and each assembly generates power, and the solid oxide fuel cell belongs to the assembly. The electric charge generated at each air electrode is collected by the air electrode current collector, and the electric charge generated at each fuel electrode of the solid oxide fuel cell belonging to the assembly is collected by the fuel electrode current collector. In the solid oxide fuel cell module, a LaCrOx-based oxide layer was formed on the surface of the air electrode, and this LaCrOx-based oxide layer was brought into contact with the air electrode-side current collector plate. During operation, the temperature is as high as 800 to 1000 ° C, and the upper end of the fuel cell is protected by the LaCrOx-based oxide layer on the surface of the air electrode. By adopting a structure that does not have an interconnector for each solid oxide fuel cell, damage due to the difference in the coefficient of thermal expansion that is likely to occur during power generation operation at high temperature is suppressed, and It can be used for a long period of time with reduced vulnerability.

According to the invention of claim 2, in the solid oxide fuel cell module of claim 1, a nickel layer is further formed on the surface of the LaCrOx-based oxide layer formed on the surface of the upper end of the air electrode. Since the nickel layer is brought into contact with the air electrode side current collector, electrical contact between the air electrode and the air electrode side current collector is improved, and current collection efficiency is increased.

[Brief description of the drawings]

FIG. 1 is a structural cross-sectional view of one embodiment of the present invention.

FIG. 2 is a cross-sectional view of the solid oxide fuel cell according to the embodiment.

FIG. 3 is a cross-sectional view showing a connection structure between an upper end portion of the fuel cell and an air electrode side current collector in the embodiment.

FIG. 4 is a sectional perspective view of the fuel cell assembly according to the embodiment.

FIG. 5 is a sectional view showing a connection structure of an upper end portion of the air electrode side current collecting member in the embodiment.

FIG. 6 is a sectional view taken along line VI-VI in FIG. 1;

FIG. 7 is a sectional view taken along line VII-VII in FIG. 1;

FIG. 8 is an equivalent circuit of a power generation operation in the embodiment.

FIG. 9 is a cross-sectional view illustrating a connection structure between an upper end portion of an air electrode side current collector and an air electrode side current collector plate according to the second embodiment of the present invention.

FIG. 10 is a sectional view showing a connection structure between an upper end portion of an air electrode side current collector and an air electrode side current collector plate according to a third embodiment of the present invention.

FIG. 11 is a perspective view of a vertical stripe type solid electrolyte fuel cell used in a conventional example.

[Explanation of symbols]

 Reference Signs List 10 solid oxide fuel cell 11 power generation chamber 12 fuel cell assembly 13 fuel supply chamber 14 fuel discharge chamber 17 heat exchanger 18 air discharge pipe 22 fuel gas 24 air 25 discharged fuel 26 discharged air 31 partition member 32 partition member 33 air electrode side Current collecting plate 34 Air electrode side current collecting member 34A Base material 34B, 34B1, 34B2 Coating layer 35 Platinum paste 36 Current collecting end 37 Nickel layer 38 Nickel paste 39 Fuel electrode side current collecting plate 40 Connection line 41 Output terminal 42 Output terminal DESCRIPTION OF SYMBOLS 101 Fuel electrode 102 Solid electrolyte 103 Air electrode 104 Fuel supply pipe 105 Conductive felt 111 LaCrOx layer 112 Nickel layer 113 Nickel paste

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masayoshi Nishimura 3-2-22-2 Nakanoshima, Kita-ku, Osaka-shi, Osaka Kansai Electric Power Co., Inc. (72) Inventor Masakatsu Nagata 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Co., Ltd. (72) Inventor Masataka Mochizuki 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Co., Ltd. (72) Inventor Riki Iwasawa 1-5-1, Kiba, Koto-ku, Tokyo F-term in Fujikura Co., Ltd. (Reference) 5H026 AA06 BB04 CV02 CV08 CX06 CX09 CX10 EE02 EE13

Claims (2)

[Claims] 1. An interconnector-less solid electrolyte fuel cell in which an air electrode, a solid electrolyte, and a fuel electrode are laminated in order from the outside to the inside, and a fuel supply pipe for current collection is inserted inside the fuel electrode. A plurality of assemblies are arranged in a matrix to form one assembly, a plurality of assemblies are accommodated in a power generation chamber, a fuel discharge chamber and a fuel supply chamber are formed above the power generation chamber, and the whole is surrounded by a heat insulating material. In each of the assemblies, a solid electrolyte having a structure in which each of the air electrodes is electrically contacted in common with an air electrode-side current collector, and each of the fuel supply pipes is electrically connected in common with the fuel electrode-side current collector. In the fuel cell module, a LaCrOx-based oxide layer is formed on a surface of a contact portion of each of the air electrodes with the air electrode-side current collector, and the LaC
A solid oxide fuel cell module, wherein an rOx-based oxide layer is brought into contact with the air electrode side current collector. 2. The solid electrolyte fuel according to claim 1, wherein a nickel layer is formed on the surface of the LaCrOx-based oxide layer, and the nickel layer is brought into contact with the air electrode side current collector. Battery module.