JPH11297344A - Solid electrolyte type fuel cell of honeycomb integrated structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an effective area, and to provide high power generation performance by operating as cells all the lateral and vertical partitioning walls in a solid electrolyte type fuel cell of honeycomb integrated structure. SOLUTION: Fuel electrode channels 14, 14, etc., with fuel electrodes (Ni-YSZ), air electrode channels 16, 16, etc., with air electrodes (La1-x Srx MnO3 ) are arranged alternately to be neighbored each other via partitioning walls of a honeycomb structure in inner walls of the honeycomb structure, comprising a solid electrolyte material 11 (yttria-stabilized zirconia(YSZ)) arranged laterally and vertically in a matrix form with a large number of honeycomb channels 12, 12, etc. The respective fuel electrodes and the respective air electrodes are electricaly connected respectively to fuel electrode side electrodes 14a and air electrode side electrodes 16a which are provided in opened end faces of the honeycomb channels 12, 12, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolyte fuel cell having a honeycomb integral structure, and more particularly, to a honeycomb structure in which a large number of honeycomb channels having a polygonal cross section are arranged vertically and horizontally by a solid electrolyte material. The present invention relates to a solid electrolyte fuel cell (hereinafter, referred to as "SOFC") having a honeycomb integral structure in which a fuel electrode and an air electrode are formed integrally and provided on the inner wall surface of each honeycomb channel.

[0002]

2. Description of the Related Art Solid oxide fuel cells (SOFCs)
A solid material with ionic conductivity is used as an electrolyte material instead of a liquid material such as a phosphoric acid aqueous solution or a molten carbonate, and has higher power generation efficiency and higher exhaust heat temperature than other fuel cells It has the characteristic. According to this, a power generation system that can be used efficiently can be constructed, and therefore, solid oxide fuel cells (SOFCs) have received particular attention in recent years.

The structure of this SOFC is generally a stacked structure in which a number of unit cells are stacked, because the voltage of each unit cell is as low as 1 V or less. Therefore, SO
In order to put FC into practical use, it is necessary to have a stacked structure in which a plurality of cells are connected in series. However, in order to further increase the capacity of the battery, in addition to increasing the number of stacked layers, a large number of batteries are connected in parallel. To be integrated. As the integrated structure, a flat plate type SOFC and a cylindrical type SOFC are well known as well-known technologies.

[0004] Among them, the flat type SOFC generally has the entire structure shown in FIG. 12, and the structure of each cell constituting the SOFC is yttria-stabilized zirconia (Y ₂ O ₃ Stabilized ZrO). ₂ )
Material or scandia stabilized zirconia (Sc ₂ O ₃
A single cell 106 in which a thin film of a fuel electrode 102 made of a nickel-cermet material and a thin film of an air electrode 104 made of a lanthanum strontium manganite material is coated on both surfaces of a solid electrolyte plate 100 made of a Stabilized ZrO ₂ ) material is made of a lanthanum chromite ceramic material or heat-resistant. A multilayer structure having a multilayer structure laminated via a separator 108 made of a metal material has already been proposed as having a good conductive function.

In order to obtain a large-capacity fuel cell using this multilayer structure, a larger number of cells and electric connecting members (flat SOFs) for stacking these cells are required.
C requires a separator, and a cylindrical SOFC uses Ni felt).

However, as described above, in the conventional stack type SOFC, the unit cell and the separator are separate members, and not only the assembling process is required, but also a fuel gas supply pipe, an air supply pipe, and the like. There is a drawback that a large number of members are required due to the necessity of the arrangement, which leads to an increase in cost. In addition, flat type SOF
In the case of C, a gas passage is provided in the connection member (separator) of each unit cell, but the shape is complicated, so that there is a problem that the manufacturing process is expensive, and as a result, the separator is expensive. Further, in the case of a cylindrical SOFC, since each unit cell is manufactured by an expensive thin film manufacturing process such as electrochemical deposition (EVD), there is a problem that the unit cell itself becomes extremely expensive.

Further, in the above-mentioned flat type SOFC, if the gas passage of the separator becomes complicated, the pressure loss becomes large, and since each unit cell is formed of a thin plate of zirconia, the structural strength becomes weak. . In addition, cylindrical type S
In the OFC, since each unit cell is formed by a porous air electrode cylinder, the structural strength is also weakened.
In addition, since the electric connection between each unit cell of the flat / cylindrical SOFC is only contact, power loss due to this contact resistance is large, and reliability in this part is reduced in the long term. Problems have also been pointed out.

Further, in the case of a flat-plate SOFC, it is necessary to match the thermal expansion coefficients of each unit cell and its connecting member (separator) from the viewpoint of manufacturing into a laminated structure, and it is difficult to perform gas sealing. is there.

Therefore, as a structure for efficiently integrating a large number of unit cells, a unit having a honeycomb structure without interposing a connecting member between the unit cells is disclosed in Japanese Patent Publication No. 60-2330.
No. 1 discloses this. In this honeycomb structure, electrodes are provided on both surfaces of each partition wall made of a honeycomb-shaped solid electrolyte material, and a desired capacity is obtained by allowing each space partitioned by each partition to function as an anode layer or a cathode layer, respectively. It is like that.

However, this Japanese Patent Publication No. Sho 60-2330
According to the honeycomb structure disclosed in Japanese Patent Publication No. 1 (1999), since a constituent member corresponding to a connecting member for electrically connecting an anode layer and a cathode layer alternately arranged by each partition is not provided, However, there may be a disadvantage that the same polar layers of the unit batteries which should be adjacent to each other independently act on the different polar layers between them with the same polar function. Then, the same polar layers function so that currents flow in opposite directions to each other, and as a result, a problem that a desired current and voltage cannot be taken out occurs. Also, when the electrical connection is made at the end, a high power generation performance cannot be expected because the current path becomes long.

In order to solve the above-mentioned problem, the present inventor has disclosed in Japanese Patent Application No. 8-354848 a honeycomb structure in which a large number of honeycomb channels having a polygonal cross section are arranged vertically and horizontally. A fuel electrode channel row in which a fuel electrode is provided on the inner wall surface of the honeycomb channel, an air electrode channel row in which an air electrode is provided on the inner wall surface of the honeycomb channel, and a honeycomb channel inner wall formed integrally with the solid electrolyte material. Separator (interconnector)
Has been proposed in which a separator (interconnector) channel row provided with is sequentially formed in a laminated shape.

According to the method disclosed in Japanese Patent Application No. 8-354848, since the unit cells are electrically connected by the separator channel, it is not necessary to connect the unit cells by electrodes such as platinum. This avoids the disadvantage that the same polarity layers of each unit cell act on the different polarity layers between them with the same polarity function, and the disadvantage that the power generation performance is reduced due to a longer current path. is there.

[0013]

However, the inner wall surface of the honeycomb structure is simply coated with the fuel electrode, the air electrode, and the separator material, and the fuel electrode channel row, the air electrode channel row, and the separator channel row are vertically arranged. In a solid oxide fuel cell formed sequentially in a stack in the direction, only the lateral partition walls separating the fuel electrode channel row and the air electrode channel row operate as a battery, so that the effective area of the battery is reduced. However, there is a problem that power generation performance is low.

An object of the present invention is to provide a honeycomb integral structure in which a fuel electrode channel having a fuel electrode provided on the inner wall surface of a honeycomb channel and an air electrode channel having an air electrode provided on the inner wall surface of the honeycomb channel are formed. In the solid oxide fuel cell (SOFC) of the above, by operating all of the horizontal partition and the vertical partition as cells,
An object of the present invention is to provide a solid oxide fuel cell (SOFC) having a honeycomb integrated structure with a high effective area and high power generation performance.

[0015]

In order to solve this problem, a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to the present invention has a large number of honeycomb channels having a polygonal cross section arranged in rows and columns. A honeycomb structure is integrally formed from a solid electrolyte material, and a fuel electrode channel provided with a fuel electrode on the inner wall surface of the honeycomb channel of the honeycomb structure and an air electrode channel provided with an air electrode on the inner wall surface of the honeycomb channel are formed. Arranged alternately so as to be adjacent to each other via a partition, each fuel electrode is electrically coupled to one open end face of the honeycomb structure, and each fuel electrode is electrically connected to the other open end face of the honeycomb structure. The gist is that the air electrode is electrically connected.

In this case, the solid electrolyte material includes:
Conventionally known yttria-stabilized zirconia (YS
Z) and scandia-stabilized zirconia (ScSZ) disclosed in Japanese Unexamined Patent Publication No. 7-6774 filed by the present applicant.
It is most suitable to use ceria (CeO ₂ ) or the like. Further, the honeycomb integral structure is formed by extruding this zirconia (ZrO ₂ ) into a zirconia honeycomb molded body in which a large number of honeycomb channels having a polygonal cross section are integrally molded, and then subjected to a firing treatment. To obtain a zirconia honeycomb.

In this case, the polygonal cross section of a large number of honeycomb channels integrally formed by extrusion molding is as follows:
It consists of a triangle, a quadrangle, a hexagon or any other shape. For example, square honeycomb channels are arranged vertically and horizontally, and fuel electrode channels and air electrode channels are alternately arranged so as to be adjacent to each other via partition walls of the honeycomb structure, or triangular honeycomb channels are arranged vertically and horizontally. For example, the fuel electrode channel and the air electrode channel are arranged alternately so as to be adjacent to each other via each side of the triangle. When the cross-sectional shape of each honeycomb channel is a square, a form in which each honeycomb channel is formed in an oblique lattice shape and the fuel electrode channel and the air electrode channel are provided alternately in a diagonal direction may be used.

Further, a fuel electrode side electrode is provided on one open end surface of the honeycomb structure, and the fuel electrodes formed on the honeycomb structure are electrically coupled to the fuel electrode side electrode. Preferably, an air electrode is provided on the other open end surface of the honeycomb structure, and the air electrodes and the air electrode formed on the honeycomb structure are electrically coupled. With such a configuration, the unit cells can be connected in parallel, and electricity generated by the SOFC can be extracted from both ends of the honeycomb channel.

Further, the thickness of the honeycomb structure in the extrusion direction is preferably 5 cm or less. If the thickness of the honeycomb structure exceeds 5 cm, the current path becomes longer, the internal resistance of the solid oxide fuel cell increases, and the power generation performance deteriorates. In addition, in order to obtain a solid oxide fuel cell having a high open circuit voltage, the honeycomb structure configured as described above may be stacked in the extrusion direction.

The fuel electrode channel and the air electrode channel of the zirconia honeycomb structure are formed by the following method as an example. That is, when forming the fuel electrode channel, the channel hole of the air electrode channel is sealed and closed, and the other end of the channel hole is covered with a braze or the like, and nickel is formed on the inner wall surface of the honeycomb channel forming the fuel electrode. -Yttria stabilized zirconia (Ni
-YSZ) is flowed or immersed in the slurry material to adhere the slurry to the inner wall surface of the honeycomb channel and one end of the channel hole. After drying the slurry, the slurry is fired to obtain a fuel electrode channel,
And a fuel electrode side electrode are formed.

In forming the air electrode channel,
Similarly, the channel hole of the fuel electrode channel is closed, and one end of the channel hole is covered with a braze or the like. La _1-x
A slurry of Sr _x MnO ₃ (x = 0.1 to 0.4) is applied by flowing or the like, and is formed by drying and firing. In addition, you may make it bake at once at the end.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

The SOFC 10 shown in FIG. 1 is a solid electrolyte material of yttria-stabilized zirconia (Y ₂ O ₃ St).
available ZrO ₂ ) or scandia stabilized zirconia (Sc ₂ O ₃ Stabilized)
ZrO ₂ ) A zirconia honeycomb structure integrally formed through an extrusion molding process and a firing process using a material,
It is formed by providing a fuel electrode and an air electrode described later.

As a result, the SOFC 10 has a large number of honeycomb channels 1 each having a rectangular cross section and both ends being open.
Are arranged in rows and columns. The thickness of the honeycomb structure can be reduced by extrusion, and is 0.1 mm to 0.3 mm.

In this zirconia honeycomb structure, the fuel electrode channels 14, 14,... And the air electrode channels 16, 16,... Are alternately arranged in the horizontal direction, and the fuel electrode channels 14, 14,. And the cathode channel 16,
16 are alternately arranged. In the figure, the honeycomb channels 12, 12,...
1 and 10 are shown.

First, the fuel electrode channels 14, 14,... Are formed by coating a slurry of nickel-yttria stabilized zirconia (Ni-YSZ) as a fuel electrode (anode: negative electrode) on inner wall surfaces 20, 20,. are those, sectional rectangular space the coating is formed by the honeycomb channel wall 20, 20 which has been subjected, hydrogen (H ₂₎ have a function as a fuel gas passage 22 which the gas flows ... doing.

The air electrode channels 16, 16,... Are provided on the inner wall surfaces 20, 20,.
Lanthanum strontium manganite (L)
a _{1− x} Sr _x MnO ₃ : x = 0.1 to 0.4) is coated, and the coated honeycomb channel inner wall surfaces 20, 20,...
Have a function as air flow paths 24 through which air flows.

FIG. 2 is an enlarged front view of the solid electrolyte fuel cell (SOFC) having a honeycomb integral structure shown in FIG.
, The honeycomb channel inner wall surfaces 20, 20, the fuel gas flow paths 22, 22, the air flow paths 24, 24, etc. are shown in an enlarged manner. With this configuration, all the partition walls of the honeycomb structure can be used as a battery, so that the effective area is six times as large as that of a conventional solid oxide fuel cell in which only horizontal partition walls operate as a battery. Become. Therefore, the reaction area is increased, and the same effect as that obtained by increasing the area of the battery is obtained, so that the power generation performance can be improved.

FIG. 3 is a side sectional view of the solid oxide fuel cell (SOFC) having a honeycomb integral structure shown in FIG.
, 16,... Are arranged alternately in the vertical direction. The inner wall surface of each fuel electrode channel 14 is coated with a fuel electrode, and the same material as the fuel electrode is also formed on one open end face of a honeycomb channel surrounded by a solid electrolyte material (zirconia) 11. This portion is coated as a fuel electrode side electrode (-electrode) 14a. Each fuel electrode has a structure integrally connected by a fuel electrode side electrode (-pole) 14a.

Similarly, the inner wall surface of each of the cathode channels 16, 16,... Is coated with an cathode,
The other opening end face of the honeycomb channel surrounded by the solid electrolyte material 11 is also coated with the same material as the air electrode, and this portion serves as the air electrode side (+ electrode) 16a. Each air electrode has a structure integrally connected by an air electrode side (+ electrode) 16a.

Therefore, in the structure shown in FIG. 1, each of the anode channels 14, 14,... And each of the cathode channels 16, 16,.
And the unit cells formed on the partition wall between them are connected in parallel. Therefore, since a single honeycomb structure does not form a stacked battery, when stacking, as shown in FIG. 4, the respective honeycomb structures may be stacked in the extrusion direction such that different electrodes are adjacent to each other. .

When the thickness D of one honeycomb structure is increased, the current flow path becomes longer and the internal resistance is increased. Therefore, the smaller the thickness D of the honeycomb structure, the smaller the power generation performance per unit volume. Will be higher. Specifically, the thickness D of the honeycomb structure is preferably 5 cm or less, and particularly preferably 1 cm or less.

Further, in order to reduce the interfacial resistance of the SOFC 10, the inner walls of the fuel electrode channels 14, 14,... And the air electrode channels 16, 16,. (Pt) A thin film may be coated in advance.

A method of manufacturing the SOFC 10 having such a configuration will be described. First, a method for manufacturing a solid electrolyte material provided for the SOFC 10 will be described.
First, powder particles of zirconia (ZrO ₂ ) as a main material and powder particles of yttria (Y ₂ O ₃ ) as a stabilizing material are mixed at an appropriate mixing ratio. The average particle size of this mixed powder is about 3 μm. In addition, when a liquid phase manufacturing process such as a sol-gel method or a coprecipitation method is applied as a method for adjusting the mixed powder of zirconia / yttria, a uniform mixed powder having few impurities can be obtained.

Next, a binder for molding is added to this mixed powder, and the cross section after firing is formed into a rectangular parallelepiped having a size of about 10 cm × 10 cm and a length of about 1 cm. Are extruded so as to form a large number of honeycomb channels 12, 12... Having both ends open. The honeycomb channels 12, 12,... Are formed such that the wall thickness between the honeycomb channels becomes about 0.1 to 0.3 mm after firing in the same manner as described above.

Then, this zirconia honeycomb formed body was
By firing at a temperature of 500 ° C. to 1700 ° C., a zirconia honeycomb made of a yttria-stabilized zirconia (YSZ) material in which yttria (Y ₂ O ₃ ) is dissolved in zirconia (ZrO ₂ ) is obtained.

Next, in forming the fuel electrode, the air electrode, and the fuel electrode and the air electrode on the zirconia honeycomb, a so-called slurry coating method is employed. That is, when forming the fuel electrode channels 14, 14,... And the fuel electrode side electrode 14a, the channel hole of the air electrode channel is sealed and closed, and the inner wall surface of the honeycomb channel forming the fuel electrode and one of the honeycomb channels are formed. Nickel (Ni) 40% by weight-zirconia (Zr
O ₂ ) A slurry obtained by converting 60% by weight of nickel-yttria-stabilized zirconia (Ni-YSZ) powder into
The slurry is flown so as to have a thickness of about 0 μm, or immersed in the slurry material, and the slurry is applied to the inner wall surface of the honeycomb channel and one end surface of the honeycomb channel.
Attach so as to be about 0 μm. After the slurry is dried, the slurry is fired at a temperature of 1200 ° C. to 1400 ° C. to form the fuel electrode channels 14 integrally connected to the fuel electrode 14a.

When the air electrode channels 16, 16,... And the air electrode 16a are formed, the channel hole of the fuel electrode channel is similarly closed, and the inner wall surface of the honeycomb channel forming the air electrode and the other end surface of the honeycomb channel are formed. Lanthanum strontium manganite (La _1-x Sr _x Mn)
O ₃ : x = 0.1 to 0.4) is applied by flowing the slurry so that its thickness becomes about 50 μm. And
If it is dried and baked at a temperature of about 1150 ° C. to 1200 ° C., the air electrode channels 16 are integrally connected to the air electrode 16a. The mixing ratio of the air electrode material is preferably about 10 to 40 mol% of strontium with respect to 90 to 60 mol% of lanthanum.

It is desirable that the firing be performed in the order of higher firing temperatures, that is, in the order of the fuel electrode channels 14, 14,... And the air electrode channels 16, 16,.
Depending on the composition of the material applied to the inner wall surface of each channel row, the slurry may be applied to all the channel rows in advance, and then may be performed at once at the end.

Scandium (S) is used as a stabilizing material.
When the powder particles of c) are applied, see JP-A-7-677.
As disclosed in Japanese Unexamined Patent Publication No. 4 (1999) -2004, zirconia (ZrO ₂
) And scandia (Sc ₂ O ₃ ) are converted to scandia (S
mixing ratio of c ₂ O ₃₎ may be adjusted to 8-15 mol%.

FIG. 5 is an exploded perspective view showing the overall structure of the SOFC 10 having the honeycomb integrated structure shown in FIGS. 1 and 2 when actually used as a fuel cell. As shown in the drawing, the SOFC 10 includes a gas supply plate 28a that discharges fuel gas and supplies air to both open ends of the above-described honeycomb structure via pressing plates 26a and 26b, respectively.
Gas supply plate 28 for supplying fuel gas and discharging air
b is provided to supply fuel gas and air from opposite directions.

As shown in FIG. 6, the holding plate 26a has fuel gas discharge holes 30, 30,.
.. Are provided in the holding plate 26b.
, And air discharge holes 44, 44, respectively, are connected to the anode channels 14, 14, respectively, of the honeycomb structure shown in FIG.
.. And the cathode channels 16, 16,...

The SOF is provided on the air supply plate 28a.
A fuel gas discharge pipe 34 for discharging the fuel gas (H ₂ ) introduced into C10 and an air introduction pipe 36 for introducing air gas (Air) to the SOFC 10 are attached. The SOFC 1 is provided on the fuel supply plate 28b.
A fuel gas introduction pipe 38 for introducing the fuel gas (H ₂ ) into the fuel cell 0 and an air discharge pipe 40 for discharging the air introduced into the SOFC 10 are provided.

That is, the fuel gas discharge holes 30, 30
Are the fuel gas flow paths 2 of the fuel electrode channels 14, 14,.
2, 22... And the air introduction holes 3
, 32 ... are provided in communication with the air flow paths 24, 24 ... of each air electrode channel row 16, 16 .... Similarly, the holding plate 26b has fuel gas introduction holes 42, 42, and air discharge holes 44, 44,.
.. And the air flow paths 24, 24,.

As shown in FIG. 7, the air supply plate 28a is provided with a comb-shaped fuel gas discharge passage 46 obliquely, which is provided in the air supply plate 28a. The gas after the reaction is discharged to the fuel gas discharge pipe 34 through the holes 30, 30,. Further, similarly to the fuel gas supply passage 46, a comb-shaped air supply passage 48 is also obliquely provided in the gas supply plate 28a, so that air introduced through the air introduction pipe 36 can be introduced. Each of the cathode channels 16, 16,... Through the air introduction holes 32, 32,.
Are formed in the air passages 24, 24,.

Similarly, the fuel gas (H) introduced through the fuel gas introduction pipe 38 is supplied to the fuel supply plate 28b.
₂ ) through the fuel gas introduction holes 42, 42,.
The fuel gas supply passage 50 in the form of a comb is provided diagonally to supply the fuel gas to the air discharge pipe 40 from the air flow paths 24, 24 through the air discharge holes 44, 44. A comb-shaped air discharge passage 52 for discharging air is also provided obliquely, so that the air introduced through the air introduction pipe 36 or the fuel gas introduction pipe 38 or the gas after the reaction of the fuel gas reacts with the air. The gas is discharged from the discharge pipe 40 and the fuel gas discharge pipe 34.

Therefore, the air introduction pipe 36, the air supply path 48, the air introduction hole 32, the air flow paths 24, 24,..., The air discharge holes 44, 44,. The fuel gas introduction pipe 38, the fuel gas supply path 50, the fuel gas introduction holes 42, 42,..., The fuel gas flow paths 22, 22,. 30, the fuel gas discharge path 46 and the fuel gas discharge pipe 34 are also provided so as to communicate with each other to form a fuel gas flow path.

When actually used, for example,
Current is taken out in the direction A shown by an arrow in FIG. 5, but in this case, the holding plates 26a located at both ends of the SOFC 10 come into contact with the air electrode 16a to serve as a positive electrode, and the holding plate 26b serves as a fuel. It becomes a negative electrode in contact with the pole side electrode 14a.

In the above configuration, the power generation mechanism of the solid oxide fuel cell (SOFC) is as follows.
That is, the air introduced from the air introduction pipe 36 passes through the air supply path 48 and the air introduction holes 32, 32,.
Of the air electrode channels 16, 16... (La _1-x S
r _x O ₃ ) upon contact with its cathode channel 16,
At 16 ..., oxygen ions ( ^O2- ) are generated.

Then, the cathode channels 16, 16
The oxygen ions (O ²⁻ ) generated at the air electrode move within the walls of the honeycomb channels 12, 12... Toward the fuel electrodes in the corresponding honeycomb channels of the corresponding fuel electrode channels 14, 14,. Corresponding anode channel 14,1
The fuel electrode of 4 ... is reached.

On the other hand, the fuel of the anode channels 14, 14,...
The gas flow paths 22, 22,...
Hydrogen gas (H₂ ) Is the fuel supply plate 28
b through the fuel gas supply path 50,
The oxygen ions (O
^2-) Is the hydrogen gas (H₂) And react with water vapor (H ₂
O), and electrons are emitted. As a result, the power generation state
can get. The air and fuel gas after the reaction are
Discharged through the gas exhaust pipe 40 and the fuel gas exhaust pipe 34.
You.

FIG. 8 is an exploded perspective view of a 2 kW module to which the above-described solid oxide fuel cell (SOFC) having a honeycomb integral structure is applied, and the SOFC 10 having a square cross section is shown.
(10 cm × 10 cm × 1 cm) are stacked in ten layers (10 cm × 10 cm × 10 cm). The output power is 500W per one
A power generation state can be obtained by a power generation mechanism similar to that shown in FIG. As shown in FIG. 8, an air electrode side electrode 16 a (+ electrode) and a fuel electrode side electrode 14 b (− electrode) are provided on both end surfaces in the pushing direction of the SOFC 10. SOF
The member illustrated at the lower part and the member illustrated at the upper part of C10 are taken out as terminals, for example, in the direction B indicated by an arrow.

That is, in the figure, a member shown below the SOFC 10 is provided with an air introduction pipe 36, a fuel gas discharge pipe 34, and the like in addition to the fuel gas discharge path 46 and the air supply path 48. And an air supply plate 28a. Furthermore, SOF
The member illustrated above the C10 is provided with a fuel gas supply path 50, an air discharge path 52, and the like (not shown) in addition to the air discharge pipe 40 and the fuel gas introduction pipe 38. 28b.

In order to obtain a larger electric power by applying the SOFC 10, as shown in FIG. 9, as shown in FIG.
Five modules were stacked in the direction along the air / fuel gas flow path to form a 10 kW module, and the 1
In order to keep the size in the direction in which the 0 kW modules are stacked, four are combined so as to form a configuration having a larger cross-sectional square shape. When assembling the modules, various connecting members such as a bus bar 58 can be used, or the air introducing pipe 36 and the air discharging pipe 40 can have a function as a connecting member.

Next, another embodiment of the cross-sectional form of the honeycomb structure of the present invention will be described with reference to FIGS. Each of the honeycomb integrated structures shown in FIGS. 10 and 11 is integrally formed through an extrusion forming process and a firing process similarly to the one shown in FIG.

FIG. 10 shows an example of a triangular cross-sectional polygonal shape. In this case, the anode channels 14, 14,... And the cathode channels 16, 16 are alternately arranged so as to be adjacent to each other via each side of the triangle.
All the partition walls of the zirconia honeycomb structure constitute unit cells.

FIG. 11 shows an example in which a polygonal cross section is formed into a diagonal lattice square shape. In this case, as in the case shown in FIG.
And the air electrode channels 16, 16 are alternately arranged so as to be adjacent to each other via the partition walls of the zirconia honeycomb structure, and all the partition walls of the zirconia honeycomb structure constitute a unit cell. .

Further, the SOF shown in FIGS.
C has an air electrode side electrode and a fuel electrode side electrode provided on both end surfaces in the pushing direction, respectively, as shown in FIG.
The generated electricity can be taken out from both ends of the honeycomb channel. Also, in order to secure a large voltage, the honeycomb structure shown in FIG. 10 or 11 may be laminated in the extrusion direction, similarly to the example shown in FIG.

The shape of the honeycomb channel may be hexagonal. In this case, all the anode channels 14, 14,... And the cathode channels 16, 16,... Cannot be arranged "alternately" due to the nature of the shape. The fuel electrode channels 14, 14,..., And all other portions may be the cathode electrode channels 16, 16,. In this way, among the partitions of the zirconia honeycomb structure, the partitions other than the portion where the air electrode channels 16, 16... Are adjacent to each other constitute a unit cell.

Although the embodiment of the present invention has been described above, as described above, by alternately arranging the fuel electrode channel and the air electrode channel, all the partition walls can be used as a battery, so that the effective area increases. Power generation performance is improved.
In addition, since the separator channel is not required, the output density per unit volume can be improved. Moreover,
Since the honeycomb structure is integrally formed of a single material, a contact portion of a component made of another material is not required in the stacked battery, and power loss due to contact resistance is reduced. In addition, since the fuel gas flow path and the air flow path in each stacked cell are linear flow paths, there is an advantage that pressure loss is reduced.

Further, a solid oxide fuel cell (SOF)
C) itself is a thin-walled structure composed of a large number of honeycomb channels, but being integrally formed of a single material contributes to extremely high structural strength. Therefore, a highly reliable structure is formed even with a material having relatively low strength such as ceria (CeO ₂ ). As for the gas seal characteristics, the inner wall along the fuel gas flow path and air flow path is completely gas-sealed against the outside atmosphere, so no special structure for gas seal is required. There are advantages. On the other hand, both ends having a polygonal cross-section need gas seals, but since the parts to be sealed have a regular shape, gas seals are easy.

Moreover, yttria-stabilized zirconia (Y
Since the integrated structure of SZ) is used, there is an advantage that the material design in consideration of the difference in the coefficient of thermal expansion of each electrode material is not required unlike the related art. Therefore, application of other materials (for example, ceria (CeO ₂ )) can be easily performed.

The present invention is not limited to the above-described embodiment.
The scope of the present invention is not limited and does not depart from the gist of the present invention.
Various modifications are possible in the box. For example, in the above example
As a material for the honeycomb structure
Zirconia (Y₂O₃ Stabilized Zr
O₂) Or Scandia stabilized zirconia (Sc ₂
O₃ Stabilized ZrO₂ Apply
As mentioned above, without being limited to this, Ytterbium
Zirconia doped with (Yb) (ZrO₂) Etc. solid
Electrolyte, cadmium (Gd), samarium (S
m), cerium oxide doped with yttrium (Y)
(CeO₂ ), Oxygen ions (O^2-) Penetrating solid
Body electrolytes are generally applicable.

[0064]

According to the solid oxide fuel cell (SOFC) having a honeycomb integral structure of the present invention, a honeycomb structure in which a large number of honeycomb channels having a polygonal cross section are arranged vertically and horizontally is integrally formed of a solid electrolyte material. So that the fuel electrode channel in which the fuel electrode is provided on the honeycomb channel inner wall surface of the honeycomb structure and the air electrode channel in which the air electrode is provided on the honeycomb channel inner wall surface are adjacent to each other via the partition wall. Since they are arranged alternately, they are excellent in structural strength and can not only reduce power loss due to contact resistance, etc., but also can use all of the partition walls of the honeycomb structure as a battery. The effective area of the battery is six times that of the conventional structure in which the air electrode channel row and the separator channel row are sequentially stacked in the vertical direction, and the power generation performance is improved. It is possible to. This SO
According to FC, the honeycomb structure is manufactured from a single material, so that not only the production cost can be reduced but also mass production can be achieved. Therefore, producing such a solid oxide fuel cell (SOFC) is extremely beneficial in industry.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

FIG. 2 is an enlarged front view of the solid oxide fuel cell (SOFC) having a honeycomb integral structure shown in FIG.

FIG. 3 is a side sectional view of the solid oxide fuel cell (SOFC) having a honeycomb integral structure shown in FIG.

FIG. 4 is a view showing a state where the solid oxide fuel cells (SOFC) having a honeycomb integral structure shown in FIG. 1 are stacked in the extrusion direction.

FIG. 5 is an exploded perspective view of a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

6 is a plan view of the holding plates 26a and 26b shown in FIG.

FIG. 7 is a plan view of an air supply plate 28a and a fuel supply plate 28b shown in FIG.

FIG. 8 is an exploded perspective view of a 2 kW module using a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

FIG. 9 is an assembly configuration diagram of a 40 kW stack using a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

FIG. 10 is a diagram showing a honeycomb structure (triangle) according to another embodiment of the present invention.

FIG. 11 is a view showing a honeycomb structure (oblique lattice shape) according to another embodiment of the present invention.

FIG. 12 is an external perspective view of a conventionally known solid oxide fuel cell (SOFC) having a laminated structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Solid oxide fuel cell (SOFC) 12 Honeycomb channel 14 Fuel electrode channel 14a Fuel electrode side electrode 16 Air electrode channel 16a Air electrode side electrode 20 Honeycomb channel inner wall surface 22 Fuel gas flow path 24 Air flow path

Claims (5)

[Claims] 1. A honeycomb structure in which a large number of honeycomb channels having a polygonal cross section are arranged vertically and horizontally by a solid electrolyte material, and a fuel electrode is provided on a honeycomb channel inner wall surface of the honeycomb structure. The fuel electrode channel and the air electrode channel having an air electrode provided on the inner wall surface of the honeycomb channel are alternately arranged so as to be adjacent to each other with a partition wall interposed therebetween. A solid electrolyte fuel cell having an integral honeycomb structure, wherein the electrodes are electrically coupled to each other and the air electrodes are electrically coupled to the other open end face of the honeycomb structure. 2. The solid electrolyte fuel according to claim 1, wherein a cross-sectional shape of each honeycomb channel of the honeycomb structure is a triangle, a quadrangle, a hexagon, or any other shape. battery. 3. The solid oxide fuel cell having a honeycomb integral structure according to claim 1, wherein the thickness of the honeycomb structure in the extrusion direction is 5 cm or less. 4. The solid electrolyte fuel cell according to claim 3, wherein the honeycomb structures are stacked in an extrusion direction. 5. The honeycomb integrated body according to claim 1, wherein the solid electrolyte material of the honeycomb structure is one selected from yttria-stabilized zirconia, scandia-stabilized zirconia, and ceria. Solid electrolyte fuel cell with structure.