JPH11297343A - Solid electrolyte type fuel cell of honeycomb integrated structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an effective area of a cell, and to enhance power generation performance by making uneven a surface operated as a fuel cell. SOLUTION: A honeycomb structure arranged vertically and laterally in a matrix form with many cross-sectionally polygonal honeycomb channels 12, 12, etc., is formed integrally out of a solid electrolyte material, fuel electrode channel rows 14, 14, etc., with fuel electrodes, air electrode channel lows 16, 16, etc., with air electrodes, separator, channel rows 18, 18, etc., with separators are formed in order into layered structure in inner wall faces of the honeycomb channels 12, 12, etc. The cross-sectional shapes of the fuel electrode channels 14, 14, etc., and the air electrode channels 16, 16, etc., are made to be combined alternately with large one and small one in their layered direction respectively, and boundary faces, operated as cells, between the respective fuel electrode channels 14, 14, etc., and the respective air electrode channels 16, 16, etc., are formed into ruggedness rectangular planar shapes.

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. A solid electrolyte fuel cell (hereinafter, referred to as "SOFC") formed integrally with a fuel electrode, an air electrode, and a separator provided on the inner wall surface of each honeycomb channel, or a honeycomb structure wall of a honeycomb structure is formed of a solid electrolyte material. Of honeycomb integrated structure formed integrally with a conductive material (separator)
It concerns OFC.

[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-plate type SOFC generally has an overall structure shown in FIG. 10, and the structure of each unit 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. FIG. 11 shows a typical example thereof, in which the fuel electrode channel rows 14, 14,..., The air electrode channel rows 16, 16,.
The honeycomb structure in which 16... Are sequentially stacked is shown.

Further, in Japanese Patent Application No. 8-3554849, a honeycomb structure wall in which a large number of honeycomb channels having a polygonal cross section are arranged vertically and horizontally is formed of a solid electrolyte material. And a separator (interconnector) material alternately forming a fuel electrode channel row in which a fuel electrode is provided on a honeycomb channel inner wall face and an air electrode channel row in which an air electrode is provided on a honeycomb channel inner wall face. Proposed is a solid oxide fuel cell which 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, there is no need to connect the unit cells by electrodes such as platinum. It is possible to avoid the inconvenience of the same polarity layer of each unit cell acting on the different polarity layer between them with the same polarity function and the inconvenience of reduced power generation performance due to a longer current path. Further, according to the method disclosed in Japanese Patent Application No. 8-3554849, the separator channel is not required, so that the output density is improved and the power loss due to the contact resistance can be avoided.

[0014]

However, when each channel of the honeycomb structure is formed in a uniform shape, for example, a square shape, the air electrode portion, the fuel electrode portion, and the separator portion are uniformly and alternately arranged. As a result, the shape of the surface that operates as a fuel cell is a simple flat surface, and the effective area of the cell is determined by the width of the honeycomb x the length of the honeycomb x the number of stacked layers, and the output density per unit volume is low. was there.

The problem to be solved by the present invention is to form 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 to form a honeycomb structure on the inner wall surface of each honeycomb channel. A surface that operates as a fuel cell in an SOFC provided with a fuel electrode, an air electrode, and a separator, or a SOFC having a honeycomb integrated structure in which a honeycomb structure wall of a honeycomb structure is integrally formed of a solid electrolyte material and a conductive material (separator). Is to increase the effective area of the battery and provide an SOFC with high power generation performance.

[0016]

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 fuel electrode channel row in which a honeycomb structure is integrally formed from a solid electrolyte material, and a fuel electrode is provided on a honeycomb channel inner wall surface of the honeycomb structure, and an air electrode channel in which an air electrode is provided on the honeycomb channel inner wall surface A row and a separator channel row in which a separator is provided on the inner wall surface of the honeycomb channel are sequentially formed in a laminated shape, and the cross-sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the laminating direction in the stacking direction. The gist is that the operating surface of the battery at the boundary between the fuel electrode channel and the air electrode channel has a rectangular planar shape with irregularities. A.

In this case, the solid electrolyte material includes:
Conventionally known yttria-stabilized zirconia (Y ₂
In addition to O ₃ Stabilized ZrO ₂ ), scandia-stabilized zirconia (Sc ₂ O ₃ Stabil) disclosed in Japanese Patent Application Laid-Open No. 7-6774 filed by the present applicant, etc.
It is most suitable to use, for example, size ZrO ₂ ) or ceria (CeO ₂ ). 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.

As a separator, lanthanum chromite (LaCrO ₃ ) is provided on the inner wall surface of the honeycomb channel.
Alternatively, in order to improve the electronic conductivity and sinterability of the lanthanum chromite system, an oxide (La _1-x Ca) in which a part of lanthanum (La) or chromium (Cr) is replaced with an alkaline earth metal or nickel (Ni). _{x Cr 1-y Ni y O} 3: x = 0
０．２0.2, y = 0０〜0.1) and the like are optimal.

Further, the cross-sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the laminating direction in the stacking direction, and the operating surface as a battery at the boundary between each fuel electrode channel and the air electrode channel has a rectangular shape. Have a planar shape.
A honeycomb having such a shape can be easily manufactured by forming a die for extrusion into a desired shape.

The fuel electrode channel row and the air electrode channel row of the zirconia honeycomb structure are formed by the following method as an example. That is, when forming the fuel electrode channel row, the channel holes of the other channel rows are sealed and closed, and nickel-yttria stabilized zirconia (Ni-YSZ) is formed on the inner wall surface of the honeycomb channel forming the fuel electrode. The slurry is flowed or immersed in the slurry material to cause the slurry to adhere to the inner wall surface of the honeycomb channel. After the slurry is dried and fired, a fuel electrode channel row is formed.

In forming the air electrode channel array, the lanthanum strontium manganite (La _1-x Sr _x MnO ₃₎ is similarly formed on the inner wall surface of the honeycomb channel forming the air electrode by closing the channel holes of the other channel arrays. x =
0.1-0.4), and adhere by flowing, etc.
It is formed by drying and firing.

Further, when a separator channel row is provided,
The same applies to the case where the lantern curtain is
Might (LaCrO)₃Or lanthanum chromite
Lanthanum (L)
a) and part of chromium (Cr)
Oxide (La) substituted with Kel (Ni)_1-xCa_xCr
_1-yNi_yO₃: X = 0-0.2, y = 0-0.1)
 After drying the slurry, it is dried and fired.
Formed. In addition, firing should be done at once at the end.
You may.

A second aspect of the present invention is to provide a honeycomb structure in which a large number of honeycomb channels having a polygonal cross section are arranged vertically and horizontally, and the honeycomb structure walls between the honeycomb channel rows are made of a solid electrolyte material and a separator material. And a fuel electrode channel array in which a fuel electrode is provided on the inner wall surface of the honeycomb channel of the honeycomb structure and an air electrode channel array in which an air electrode is provided on the inner wall surface of the honeycomb channel are sequentially laminated. And the cross-sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the stacking direction in the stacking direction, and the operating surface as a battery at the boundary between each fuel electrode channel and the air electrode channel has irregularities. The gist of the present invention is that it has a rectangular planar shape.

In this case, the solid electrolyte material includes:
Yttria stabilized zirconia (Y ₂ O ₃ Stabil
sized ZrO ₂ ), scandia-stabilized zirconia (Sc ₂ O ₃ Stabilized ZrO ₂ ),
It is optimal to apply ceria (CeO ₂ ),
And lanthanum chromite (LaC
rO ₃ ) or an oxide obtained by replacing a part of lanthanum (La) or chromium (Cr) with an alkaline earth metal or nickel (Ni) in a lanthanum chromite system (La _{1- x} Ca
_{x Cr 1-y Ni y O} 3: x = 0~0.2, y = 0~
The point where it is optimal to apply 0.1) or the like is as described above.

Further, the honeycomb integral structure is characterized in that the solid electrolyte material and the separator material are extruded from separate pouring ports of an extruder into dies (dies), respectively, so that the honeycomb channel wall made of the solid electrolyte material and the separator material are used. The honeycomb channel walls are formed, and are alternately formed in a laminated shape. Then, a honeycomb formed body having a two-layer structure of zirconia / lanthanum chromite formed by integrally forming a large number of honeycomb channels having a polygonal cross section is fired, and then subjected to a firing treatment. Is obtained as

In this case, a fuel electrode channel row in which a fuel electrode is provided on an inner wall surface of a honeycomb channel of a honeycomb structure integrally formed by extrusion molding, and an air electrode in which an air electrode is provided on an inner wall surface of the honeycomb channel The channel rows are sequentially formed in a stacked shape, and the sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the stacking direction in the stacking direction, so as to form a battery at the boundary between each fuel electrode channel and the air electrode channel. As described above, the operation surface has a rectangular planar shape having irregularities.

[0027]

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, an air electrode, and a separator electrode described later.

Thus, the SOFC 10 has a structure in which a large number of honeycomb channels 12, 12... Having a rectangular cross section and open at both ends 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 the zirconia honeycomb structure, honeycomb channels or separator channels having the same polarity are arranged in the horizontal direction, and fuel electrode channel rows 14, 14... 16
, And separator channel rows 18, 18,... For electrically connecting the unit cells are sequentially formed in a laminated shape. In the figure, the separator channel rows 18, 1
8 shows a structure in which unit cells are stacked in four stages.

First, the fuel electrode channel rows 14, 14,...
Are coated with a slurry of nickel-yttria-stabilized zirconia (Ni-YSZ) as a fuel electrode (anode: -electrode) on the inner wall surfaces 20, 20, ... of the honeycomb channels, and the inner wall surfaces of the coated honeycomb channels are provided. The space having a rectangular cross section formed by 20, 20,... Has a function as fuel gas flow paths 22, 22,... Through which hydrogen (H ₂ ) gas flows.

The air electrode channel rows 16, 16... Are provided with air electrodes (cathode: +
Lanthanum strontium manganite (L)
_{a 1 -x Sr x MnO 3:} x = 0.1~0.4) are those slurry is formed by coating, the honeycomb channel wall 20, 20 the coating is applied ...
Have a function as air flow paths 24 through which air flows.

The separator channel rows 18, 18... Are made of lanthanum chromite (LaCrO ₃ ) or lanthanum chromite-based electronic conductors, which are conductors for connecting cells in series to the inner wall surfaces 20, 20. for binding of improvement, lanthanum (La) and oxides obtained by substituting chromium some alkaline earth metals and nickel _{(Cr) (Ni) (La} 1-x Ca x Cr
_1-y Ni _y O ₃ : x = 0 to 0.2, y = 0 to 0.1)
Is coated.

Further, the separator channel rows 18, 18
.. Do not require gas to pass therethrough, and therefore have a horizontally long rectangular shape of equal size and a reduced cross-sectional area, while the fuel electrode channel rows 14, 14. ... means that rectangles having different sizes are alternately arranged.

Therefore, the fuel electrode channel rows 14, 14,...
Are separated by a horizontal partition and a part of the vertical partition. Not only the horizontal partition but also a part of the vertical partition is used as a battery. Operate. This makes it possible to double the effective area of the battery, unlike the conventional structure in which channel rows having a square cross section are arranged. Accordingly, 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. 2 is an enlarged front view of the solid oxide fuel cell (SOFC) having a honeycomb integral structure shown in FIG. 1 and includes fuel electrode channel rows 14, 14,... (A), and air electrode channel rows 16, 16. ... (C), separator channel row 1
8, 18 ... (S), honeycomb channel inner wall surfaces 20, 20
..., fuel gas flow paths 22, 22, ... and air flow paths 24, 24
… Etc. are shown enlarged.

It should be noted that the separator channel rows 18, 18,...
When the yttria-stabilized zirconia (YSZ) layer is made to have electronic conductivity, titanium (Ti), iron (Fe),
Nickel (Ni), terbium (Tb), cerium (C
e), one or more elements such as neodymium (Nd), iridium (Ir), manganese (Mn), and vanadium (V).

In order to reduce the interfacial resistance of the SOFC 10, an aqueous solution of a platinum complex such as paradichloroammineplatinum is used for the inner walls of the fuel electrode channel rows 14, 14,... And the air electrode channel rows 16, 16,. In this case, a platinum (Pt) thin film may be coated in advance. Further, in order to reduce the DC resistance, the air electrode channel rows 16, 1
6 ... Lantern strontium manga night (La
_1-x Sr _x MnO ₃ ) as well as lanthanum strontium cobaltite (La _1-x Sr)
_x CoO ₃ ).

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 the mixed powder and molded into a rectangular parallelepiped having a size of about 10 cm × 10 cm and a length of about 20 cm after firing. Are extruded so that a large number of rectangular honeycomb channels 12, 12... 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.

The 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, a fuel electrode and an empty
When forming the air electrode or separator,
A loose slurry coating method is employed. That is,
In forming the parator channel rows 18, 18,...
Seal and close the channel hole of the channel row of
Inner wall of honeycomb channel forming separator channel
Lanthanum chromite (LaCrO)₃ ) Or la
Electron conductivity and sinterability have been improved for
Lanthanum (La) and part of chrome (Cr)
Oxide (La) substituted with earth metal or nickel (Ni)
_1-xCa_xCr _1-yNi_yO₃: X = 0 to 0.2,
(y = 0 to 0.1).

When forming the fuel electrode channel rows 14, 14,..., Similarly, the channel holes of the other channel rows are sealed and closed, and nickel (Ni) is formed on the inner wall surface of the honeycomb channel forming the fuel electrode. ) 40% by weight of zirconia (ZrO ₂ ) 60% by weight of nickel-yttria-stabilized zirconia (Ni-YSZ) powder made into a slurry having a thickness of about 50 μm is flown into the slurry, The slurry is immersed and adhered to the inner wall surface of the honeycomb channel so that its thickness is also about 50 μm. Then, after drying the slurry, 1
By firing at a temperature of 200 ° C. to 1400 ° C., the fuel electrode channel rows 14 are formed.

Further, when forming the air electrode channel arrays 16, 16,..., The lanthanum strontium manganite (La _1-x Sr) is similarly formed on the inner wall surface of the honeycomb channel which blocks the channel holes of the other channel arrays and forms the air electrode. _x M
(nO ₃ : x = 0.1 to 0.4) is applied by flowing so that the thickness thereof becomes about 50 μm. Then, if it is dried and fired at a temperature of about 1150 ° C. to 1200 ° C., the air electrode channel rows 16 are formed. 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.

The firing is performed in the order of higher firing temperatures, that is, the separator channel rows 18, 18,..., The fuel electrode channel rows 14, 14, and the air electrode channel rows 16, 16,.
However, 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.

Further, 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. 3 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 FIG. 1, the SOFC 10 has a gas supply plate 28a for supplying fuel gas and air via pressing plates 26a and 26b at both open ends of the above-mentioned honeycomb structure, and a gas discharge plate 28b for discharging fuel gas and air. Is provided. As shown in FIG. 4, the presser plate 26a has fuel gas introduction holes 30, 30,... And air introduction holes 32, 32, respectively, of the fuel electrode channel rows 14, 14,... Of the honeycomb structure shown in FIG. Channel and cathode channel rows 16,1
6 are provided in a horizontal row corresponding to the channels.

The gas supply plate 28a has a fuel gas introduction pipe 34 for introducing the fuel gas (H ₂ ) into the SOFC 10, and an air introduction pipe 36 for introducing the air gas (Air) into the SOFC 10 as well. Is attached. Further, the SOFC1 is provided on the gas discharge plate 28b.
A fuel gas discharge pipe 38 for discharging the fuel gas (H ₂ ) introduced into the SOFC 10 and an air discharge pipe 40 for discharging the air similarly introduced into the SOFC 10 are provided.

That is, the fuel gas introduction holes 30, 30
... are provided in communication with the fuel gas flow paths 22, 22, ... of the respective honeycomb channels of the fuel electrode channel rows 14, 14, ...
The air introduction holes 32, 32,...
Air passages 24, 24 of each of the honeycomb channels 6, 16,...
… Are provided. Similarly, the holding plate 26
. b and the fuel gas discharge holes 42, 42.
Are provided in communication with the fuel gas passages 22, 22, and the air passages 24, 24, respectively.

As shown in FIG. 5, a comb-shaped fuel gas supply passage 46 is provided in the gas supply plate 28a.
This means that the fuel gas (H ₂ ) introduced through the fuel gas introduction pipe 34 is supplied through the fuel gas introduction holes 30, 30. Are supplied to the flow paths 22, 22,. The gas supply plate 28a is connected to the fuel gas supply passage 46.
A comb-shaped air supply passage 48 is also provided so as to alternately intersect with the air supply pipe 36, and thereby the air introduction pipe 36 is provided.
Are supplied to the air flow paths 24 formed in each channel of the air electrode channel rows 16, 16... Through the air introduction holes 32, 32. .

A fuel gas discharge passage 50 for discharging the reacted gas from the fuel gas flow passages 22 to the fuel gas discharge pipe 38 through the fuel gas discharge holes 42, 42 is provided in the gas discharge plate 28b. Are provided, and the air flow paths 24 and 2 are provided.
4 through the air discharge holes 44, 44,.
A comb-shaped air discharge passage 52 is also provided for discharging air after the reaction to zero, so that the air or fuel gas introduced through the air introduction pipe 36 or the fuel gas introduction pipe 34 reacts. Are discharged from the air discharge pipe 40 and the fuel gas discharge pipe 38.

Accordingly, 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 34, the fuel gas supply path 46, the fuel gas introduction holes 30, 30,..., The fuel gas flow paths 22, 22,. 42, the fuel gas discharge path 50 and the fuel gas discharge pipe 38 are also provided in communication with each other to form a fuel gas flow path.

When actually used, for example,
A current is taken out in a direction A shown by an arrow in FIG. 3. In this case, the electrode terminal plates 54 and 56 as shown in FIG.

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,.
The air electrode (La _1-x
Sr _x O ₃ ), the air electrode channel row 1
At 6, 16,..., Oxygen ions (O ²⁻ ) are generated.

Then, the air electrode channel rows 16, 1
Oxygen ions (O ²⁻ ) generated at the air electrodes No. 6 toward the corresponding fuel channels in the corresponding honeycomb channels of the corresponding fuel electrode channel rows 14, 14.
… Move inside the wall of the corresponding anode channel 1
The fuel electrodes of 4, 14, ... are reached.

On the other hand, the hydrogen gas (H ₂ ) introduced from the fuel gas introduction pipe 34 is also supplied to the gas supply plate 2 in the fuel gas passages 22 of the fuel electrode channel rows 14.
8a, the oxygen ions (O ²⁻ ) that have moved from the air electrode channel rows 16, 16,... React with the hydrogen gas (H ₂ ) to produce water vapor (H ₂ O). ), And electrons are emitted. Thereby, a power generation state is obtained. And the air and fuel gas after the reaction are
Each is discharged through an air discharge pipe 40 and a fuel gas discharge pipe 38.

FIG. 6 is an exploded perspective view of a 2 kW module to which the above-described solid electrolyte fuel cell (SOFC) having a honeycomb integral structure is applied.
(10 cm × 10 cm × 20 cm). The output power is 500 W per one, and a power generation state can be obtained by a power generation mechanism similar to that shown in FIG. As shown in FIG.
Electrode terminal plates 54 and 56 are provided on the outer surface of the OFC 10 so as to face each other, and the generated electricity is extracted from these electrode terminal plates 54 and 56 in, for example, a direction B shown by an arrow.

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

In order to obtain a larger electric power by applying the SOFC 10, as shown in FIG. 7, 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. 8 and 9 is integrally formed through an extrusion forming process and a firing process similarly to the one shown in FIG.

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)
Zirconia structural wall 1 formed from ZrO ₂ ) material
, And separator structure walls 19 formed of a lanthanum chromite (LaCrO ₃ ) material, which is a separator material, are formed alternately with a predetermined thickness through an extrusion molding process and a firing process. The zirconia honeycomb structure formed integrally is provided with a fuel electrode and an air electrode described later.

Although not shown, a platinum (Pt) thin film is previously coated using an aqueous solution of a platinum complex such as paradichloroammineplatinum in order to reduce the interface resistance of the SOFC 10. Further, in order to reduce the DC resistance, lanthanum strontium manganite (La _1-x Sr _x Mn) is added to the air electrode channel rows 16, 16.
Not only O ₃ ) but also lanthanum strontium cobaltite (La _1-x Sr _x CoO ₃ ) is coated on the inner wall.

As a result, the SOFC 10 has a large number of honeycomb channels 1 each having a rectangular cross section and open at both ends.
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 the zirconia honeycomb structure, honeycomb channels having the same polarity are arranged in the horizontal direction, and the fuel electrode channel rows 14, 14... And the air electrode channel rows 16, 16,. Are sequentially and alternately formed in a stacked manner, and the fuel electrode channel rows 14, 14,... And the air electrode channel rows 16, 16,. FIG. 1 shows a structure in which unit cells made of a solid electrolyte material (zirconia) are stacked in five stages via separator structure walls 19, 19.

First, the fuel electrode channel rows 14, 14,...
Are coated with a slurry of nickel-yttria-stabilized zirconia (Ni-YSZ) as a fuel electrode (anode: -electrode) on the inner wall surfaces 20, 20, ... of the honeycomb channels, and the inner wall surfaces of the coated honeycomb channels are provided. The space having a rectangular cross section formed by 20, 20,... Has a function as fuel gas flow paths 22, 22,... Through which hydrogen (H ₂ ) gas flows.

The air electrode channel rows 16, 16...
Lanthanum strontium manganite (La _1-x Sr _x MnO ₃ : x = 0.1 to 0.4) as an air electrode (cathode: + pole) on the inner wall surfaces 20, 20... Of the honeycomb channels.
Is coated, and the honeycomb channel inner wall surface 20,
20 have a function as air flow paths 24 through which air flows.

As the material of the separator structure walls 19, lanthanum chromite (LaCrO ₃ ) or lanthanum chromite is used to improve electronic conductivity and sinterability, and part of lanthanum (La) or chromium (Cr) is used. (L) in which is substituted by an alkaline earth metal or nickel (Ni)
_{a 1-x Ca x Cr 1} -y Ni y O 3: x = 0~0.
2, y = 0 to 0.1) is used.

FIG. 9 is an enlarged front view of the solid oxide fuel cell (SOFC) having a honeycomb integral structure shown in FIG. 8, and is sandwiched between zirconia structure walls 11, 11 and separator structure walls 19, 19. .. (A) and air electrode channel arrays 16, 16,... (C) are formed in the two honeycomb channel arrays. Are coated with the fuel electrode, and the air electrode channel rows 16, 16 are coated with the air electrode. Also, in the same figure, the honeycomb channel inner wall surfaces 20, 20,.
, And air passages 24, 24, etc. are shown in an enlarged manner.

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. When applying powder particles of scandium (Sc) as a stabilizing material,
Scandia (Sc ₂ ) against zirconia (ZrO ₂ )
As described above, the amount of O ₃ ) may be adjusted so as to be 8 to 15 mol%.

Next, a method for manufacturing a separator material will be described. Lanthanum chromite (LaCrO ₃ ) or lanthanum chromite-based oxide in which a part of lanthanum (La) or chromium (Cr) is replaced with alkaline earth metal or nickel (Ni) to improve electronic conductivity and sinterability
_{(La 1-x Ca x Cr} 1-y Ni y O 3: x = 0~
0.2, y = 0-0.1). If a liquid phase production process such as a sol-gel method or a coprecipitation method is applied, a uniform mixed powder with few impurities can be obtained.

In this way, the yttria-stabilized zirconia material and the lanthanum chromite material are simultaneously extruded from separate pouring ports by an extruder in which a die (die) having a honeycomb structure cross section is set. This allows
The size after firing is about 10 cm × 10 cm, and a formed body in which rectangular honeycomb channels 12, 12... Having different sizes are alternately arranged is extruded. Are formed such that the thickness thereof becomes about 0.1 to 0.3 mm after firing.

The honeycomb formed body of zirconia / lanthanum chromite is fired at a temperature of 1500 ° C. to 1700 ° C. As a result, a honeycomb fired body of zirconia / lanthanum chromite made of a yttria-stabilized zirconia (YSZ) material in which yttria (Y ₂ O ₃ ) is dissolved in zirconia (ZrO ₂ ) and a lanthanum chromite material is obtained.

The point that a fuel electrode and an air electrode are formed on the obtained zirconia honeycomb by a slurry coating method is the same as described above. Thereby, the fuel electrode channel row 1 in which rectangles having different sizes are alternately arranged.
, 4 and 14 and cathode channel rows 16, 16 ...
Moreover, the fuel cell channel rows 14, 14 of one unit cell
, And the air electrode channel rows 16, 1 of another unit battery
6 can obtain an SOFC partitioned by a partition wall made of lanthanum chromite.

The SOFC obtained in this manner is composed of the anode electrode channel rows 14, 14,.
6 are separated by a horizontal partition and a part of the vertical partition, and not only the horizontal partition but also a part of the vertical partition operates as a battery. This makes it possible to double the effective area of the battery, unlike the conventional structure in which channel rows having a square cross section are arranged. Accordingly, 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.

Although the embodiments of the present invention have been described above, as described above, the power generation performance is improved by providing the fuel electrode channel row and the air electrode channel row in which large and small rectangles having different sizes are alternately arranged. When the honeycomb structure is integrally formed using zirconia and lanthanum chromite materials, a contact portion of a separate component member 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, the honeycomb structure of zirconia / lanthanum chromite is made of yttria-stabilized zirconia (Y
SZ) or scandia stabilized zirconia (ScS
The battery resistance is lower than that of the zirconia honeycomb composed only of Z), and high output can be achieved. In addition, if the thickness of each stacked body is reduced, the power generation density of the battery increases, so that the performance of the material can be improved from both the material side and the structural side.

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 contributes to extremely high structural strength. Therefore, ceria (Ce
Even with a material having relatively low strength such as O ₂ ), a highly reliable structure is formed. 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 although the parts to be sealed are different in size, the gas seals are easy because they have a regular shape.

The present invention is not at all limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the material of the zirconia structure wall of the honeycomb structure is yttria-stabilized zirconia (Y ₂ O ₃ Stab).
illuminated ZrO ₂ ) or scandia stabilized zirconia (Sc ₂ O ₃ Stabilized Zr)
O ₂ ) was applied. However, the present invention is not limited to this, and a solid electrolyte such as zirconia (ZrO ₂ ) doped with ytterbium (Yb) or cadmium (G
d), samarium (Sm), yttrium (Y) doped cerium oxide (CeO ₂ ), etc.
^2- ) A solid electrolyte that permeates through is generally applicable.

[0079]

According to the solid electrolyte 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. A fuel electrode channel row in which a fuel electrode is provided on a honeycomb channel inner wall face of the honeycomb structure, an air electrode channel row in which an air electrode is provided on a honeycomb channel inner wall face, and a separator provided on a honeycomb channel inner wall face. And the separator channel rows are sequentially formed in a laminated shape, and the sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the laminating direction in the stacking direction, and the cells at the boundary between each fuel electrode channel and the air electrode channel are formed. The operating surface of the battery has a rectangular flat shape with irregularities, so the effective area of the battery can be increased about twice and the battery area can be increased. The same effect as is obtained.

Further, the honeycomb structure walls are alternately and integrally formed of a solid electrolyte material and a separator material, and a fuel electrode channel row and an air electrode channel row are formed thereon in a laminated manner. Since the cross-sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the laminating direction in the laminating direction, the operating surface as a battery at the boundary between each of the fuel electrode channel and the air electrode channel has a rectangular planar shape having irregularities. The effective area of the battery can be approximately doubled, and the same effect as increasing the area of the battery can be obtained. In addition, by adopting the honeycomb integrated structure, not only the structural strength is excellent, but also since there is no contact portion, it is possible to reduce the power loss due to the contact resistance or to achieve a higher output. In addition, the honeycomb structure of this SOFC is manufactured integrally by simultaneous extrusion molding of two kinds of materials, and since it is easy to form a fuel electrode and an air electrode, mass production can be achieved. It is very promising.

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

FIG. 4 is a plan view of the holding plates 26a and 26b shown in FIG.

FIG. 5 is a plan view of a gas supply plate 28a and a gas discharge plate 28b shown in FIG.

FIG. 6 is an exploded perspective view of a 4 kW module using a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

FIG. 7 is an assembly configuration diagram of an 80 kW stack using a solid oxide fuel cell (SOFC) having a honeycomb integral structure according to an embodiment of the present invention.

FIG. 8 is a diagram showing a honeycomb structure according to another embodiment of the present invention.

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

FIG. 10 is an external perspective view of a conventional solid oxide fuel cell (SOFC) having a laminated structure.

FIG. 11 is an external perspective view of a solid oxide fuel cell (SOFC) having a honeycomb integral structure which is generally known in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Solid oxide fuel cell (SOFC) 11 Zirconia structure wall 12 Honeycomb channel 14 Fuel electrode channel row 16 Air electrode channel row 18 Separator channel row 19 Separator structure wall 20 Honeycomb channel inner wall face 22 Fuel gas flow path 24 Air flow path

Claims (7)

[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. A fuel electrode channel array, an air electrode channel array in which an air electrode is provided on a honeycomb channel inner wall surface, and a separator channel array in which a separator is provided on a honeycomb channel inner wall surface, are sequentially formed in a laminated shape, and the fuel electrode The cross-sectional shapes of the channel and the air electrode channel are alternately large and small in the stacking direction, and the operating surface as a battery at the boundary between each fuel electrode channel and the air electrode channel has a rectangular planar shape with irregularities. Solid electrolyte fuel cell with a honeycomb integral structure. 2. The honeycomb integrated structure according to claim 1, wherein the solid electrolyte material of the honeycomb structure is one selected from the group consisting of yttria-stabilized zirconia, scandia-stabilized zirconia, and ceria. Solid oxide fuel cell. 3. The separator of the honeycomb structure is lanthanum chromite or an oxide selected from lanthanum chromite and an oxide obtained by substituting a part of lanthanum or chromium with alkaline earth metal or nickel. The solid electrolyte fuel cell having a honeycomb integral structure according to claim 1. 4. A honeycomb structure wall in which a large number of honeycomb channels having a polygonal cross-section are arranged in rows and columns alternately formed of a honeycomb structure wall formed of a solid electrolyte material and a separator material between respective honeycomb channel rows. A fuel electrode channel row in which a fuel electrode is provided on a honeycomb channel inner wall surface of the honeycomb structure, and an air electrode channel row in which an air electrode is provided on a honeycomb channel inner wall face are sequentially formed in a stacked shape, The cross-sectional shapes of the fuel electrode channel and the air electrode channel are alternately combined in the stacking direction in the stacking direction, and the operating surface as a battery at the boundary between each of the fuel electrode channel and the air electrode channel has a rectangular planar shape having irregularities. A solid electrolyte fuel cell with a honeycomb integral structure. 5. The honeycomb integrated structure according to claim 4, wherein the solid electrolyte material of the honeycomb structure is one selected from the group consisting of yttria-stabilized zirconia, scandia-stabilized zirconia, and ceria. Solid oxide fuel cell. 6. The lanthanum chromite or the oxide of lanthanum chromium in which a part of lanthanum or chromium is replaced with an alkaline earth metal or nickel is selected from the group consisting of lanthanum chromite and a separator material of the honeycomb structure. The solid electrolyte fuel cell having a honeycomb integral structure according to claim 4 or 5. 7. The honeycomb integrated structure according to claim 4, wherein the honeycomb structure is formed by integrally extruding two kinds of materials, a solid electrolyte material and a separator material. Solid oxide fuel cell.