JPH1140175A - Manufacture of electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method with high productivity by enhancing adhesion between an electrode and a solid electrolyte layer and between the electrode and a dense body and reducing polarization on the interfaces, when manufacturing an electrochemical cell. SOLUTION: An electrochemical cell equipped with a solid electrolyte layer, an electrode made on the one side of the solid electrolyte layer, another electrode on the other side and a dense body layer integrated with the electrode on the one side is manufactured by this method. As matrix soil 15 A to mold the electrode on one side and matrix soil 16 A to form a dense body layer is being pushed out individually and continuously one by one, while they merge in a mouthpiece 1. A laminated molding body equipped with at least a molding body of the dense body layer, a molding body of the electrode on one side and a molding of the solid electrolyte layer is obtained by merging matrix soil 14 A to mold the solid electrolyte layer to the electrode 15 B on the one side in the mouthpiece, as it is being pushed out continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrochemical cell such as a solid oxide fuel cell, a steam electrolysis cell, an oxygen pump, a Knox decomposition cell and the like.

[0002]

2. Description of the Related Art Solid oxide fuel cells are roughly classified into a so-called flat type and a cylindrical type. In a plate-type solid oxide fuel cell, a so-called separator and a power generation layer are alternately stacked to form a power generation stack.
In JP-A-5-54897, a fuel electrode and an air electrode are respectively formed to form a power generation layer, and an interconnector is formed. Ceramic powder and an organic binder are interposed between the power generation layer and the interconnector. A laminate is produced by sandwiching a thin film containing, and the laminate is heat-treated to join the power generation layer and the interconnector.

In Japanese Patent Application Laid-Open No. Hei 6-68885, a green molded body of an interconnector and a green molded body of an air electrode side distributor are laminated, and the laminated body is integrally sintered to form an interconnector. Joining with a distributor is described. In this method, a stress relaxation layer for relaxing stress between the green molded bodies is formed between the two green molded bodies by applying a material having an extremely different heat shrinkage behavior from the two green molded bodies. This stress relieving layer is finely broken during shrinkage by firing, whereby the stress is relieved.

[0004]

However, the flat solid electrolyte fuel cells manufactured by these manufacturing methods have poor adhesion at the interface between the electrode and the solid electrolyte, tend to cause polarization, and have a high resistance. Layers are easy to form. In addition, since it is necessary to perform sintering for each layer constituting the solid oxide fuel cell, it takes a long time to manufacture, and the productivity is low. Further, during a plurality of sintering steps, the characteristics of each layer deteriorate from desired characteristics. For example, if the air electrode is fired first, the air electrode will be subjected to a plurality of firing steps, during which time the sintering of the air electrode will further proceed, and the porosity of the air electrode will decrease. Come. Further, a high-resistance layer is easily generated between the air electrode and the interconnector.

An object of the present invention is to provide a solid electrolyte layer, one electrode and the other electrode formed on both sides of the solid electrolyte layer, and a dense layer integrated with the one electrode. When manufacturing an electrochemical cell, it is necessary to improve the adhesion between the electrode and the solid electrolyte layer, and between the electrode and the dense body layer, to reduce the polarization at the interface between them, and to provide a production method with high productivity. To provide.

[0006]

SUMMARY OF THE INVENTION The present invention provides a solid electrolyte layer, one electrode and the other electrode formed on both sides of the solid electrolyte layer, and a dense body layer integrated with one electrode. A method for producing an electrochemical cell comprising: a fill for forming one electrode and a fill for forming a dense body layer, while continuously extruding each separately, And then, while continuously extruding the fill for forming the solid electrolyte layer, by joining on one of the electrodes in a die, at least the compact of the dense body layer and the compact of one electrode and the solid The present invention relates to a method for obtaining a laminated molded article including a molded article of an electrolyte layer.

[0007] In the course of exploring a method for efficiently manufacturing an electrochemical cell having the above-mentioned layers, the inventor of the present invention has found that a potting material for forming one electrode and a potting material for forming a dense body layer. It is conceived that the soil and the soil are merged in the die while continuously extruding them separately, and that the soil for forming the solid electrolyte layer is continuously extruded and merged on one electrode in the die. did.

As a result, the adhesion between the electrode and the solid electrolyte layer and the adhesion between the electrode and the dense body layer are improved, and the polarization at the interface between them can be reduced. At the interface between the electrode and the solid electrolyte layer, a fill for forming one electrode and a fill for forming the solid electrolyte layer,
This is probably because the materials were mixed appropriately at the interface between them by extruding them separately while continuously extruding them, and a large number of three-layer interfaces were formed. Similarly, at the interface between the electrode and the dense body layer, the respective materials are appropriately mixed at the interface and the adhesion strength is increased, so that peeling or the like hardly occurs and the interface resistance is reduced. Moreover,
Since the productivity is extremely high and the number of firings is one or two, alteration such as increase in porosity and dimensional change of the electrode layer can be prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a fill material for forming one electrode and a fill material for forming a dense body layer are separately and continuously extruded and joined in a die. Next, while continuously extruding the clay for forming the solid electrolyte layer and the kneaded clay for forming the other electrode in a laminated state, they can be merged on one electrode in the die. This makes it possible to mold all of the main components of the electrochemical cell including the pair of electrodes, the dense body layer, and the solid electrolyte layer in a single type of die, so that only one firing step is required.

In the case where a gas flow path extending in the extrusion direction of each fill is formed between the dense body layer and one of the electrodes, a gas flow path for forming the gas flow path is formed in the base. The child needs to be fixed. At this time, the upstream end of the core is located upstream of or near the same point as the confluence of the fill for forming the dense body layer and the fill for forming one electrode. Is preferably located. Thus, before or at the same time as the fill for forming the dense body layer and the fill for forming the one electrode are merged, it is possible to form a groove for forming a gas flow path. it can.

After the fill for forming the dense body layer and the fill for forming one electrode have merged, they collide with the core for forming the gas flow passage in the die. Then, at this time, the interfaces of the respective clays are already strongly bonded, and this bonded interface is divided into two by the core. For this reason, a large uneven pressure is applied to the vicinity of the interface, the position of the bonding interface is liable to fluctuate, and the size of the molded body is liable to be greatly changed.

In the electrochemical cell, the cross section of the gas flow path can be polygonal. In this case, an arc is formed at each corner of the polygonal gas flow path. Is preferred. This makes it easier for the current to be dispersed to the rounded portion during power generation or the like, making it less likely for the current to concentrate.

Further, it is preferable that the cross section of the gas flow path has a closed curved surface, so that the above-mentioned current concentration hardly occurs. Although such a closed surface is not particularly limited, a circular or elliptical shape is preferable.

The relative density of the dense body layer needs to be 94% or more in order to maintain airtightness. The relative density of the dense layer is up to 100%. Further, the relative density of the electrode is preferably 60% or more from the viewpoint of strength, and is preferably 85% or less, and 75% or less in order to improve the flowability of the gas for power generation. Is more preferred.

The electrochemical cell of the present invention can be used as an oxygen pump. Further, the electrochemical cell of the present invention can be used as a high-temperature steam electrolysis cell. This cell can be used for a hydrogen production device and a steam removal device.
In this case, the following reaction occurs at each electrode.

[0016]

Cathode: H ₂ O + 2e ⁻ → H ₂ + O ² −Anode: O ^{2 −} → 2e ⁻ + 1 / 2O ₂

Furthermore, the electrochemical cell of the present invention can be used as a NOx decomposition cell. This disassembly cell is used for automobiles,
It can be used as a device for purifying exhaust gas from a power generator. At present, NOx generated from a gasoline engine is handled by a three-way catalyst. However, when the number of fuel-efficient engines such as lean burn engines and diesel engines increases, the amount of oxygen in the exhaust gas of these engines is large, so that the three-way catalyst does not function.

Here, when the electrochemical cell of the present invention is used as a NOx decomposition cell, oxygen in exhaust gas is removed through a solid electrolyte membrane, and NOx is electrolyzed to be decomposed into N ₂ and O ^2- . Oxygen generated by this decomposition can also be removed. In addition, along with this process, steam in the exhaust gas is electrolyzed to generate hydrogen and oxygen, and this hydrogen is converted into NO.
the x is reduced to N _2.

In the case of a NOx decomposition cell, the solid electrolyte membrane is particularly preferably made of a cerium oxide-based ceramic, and the cathode material is preferably made of palladium or nickel-zirconia cermet.

In the present invention, one electrode to be laminated first with the dense body layer includes both an air electrode and a fuel electrode, but the air electrode is more preferable. In the case of steam electrolysis, both the anode and the cathode are included, but the anode is more preferable. Moreover, it is particularly preferable to join the self-supporting (self-supporting) air electrode to the dense body layer.

FIG. 1 is a cross-sectional view of a die for extrusion molding which can be suitably used in the manufacturing method of the present invention, which is cut in a length direction thereof. FIG. 2A is a front view showing the entrance side of the kneaded clay supply unit 3, FIG. 2B is a side view of the kneaded clay supply unit 3, and FIG. It is a front view showing the state where part 3 was seen from the exit side. FIG. 3 shows III of the base 1 of FIG.
FIG. 4 is a sectional view taken along line IV-IV of FIG. 1, and FIG. 5 is a sectional view taken along line IV-IV of FIG.
FIG. 4 is a cross-sectional view showing a laminated molded body 21 obtained by the above method.
The following describes an example in which the present invention is applied to the production of a solid oxide fuel cell.

The base 1 includes a base body 10 and a pair of clay supplying units 2 and 3. The kneaded material supply unit 3 is shown in FIG.
As shown in (a), (b), and (c), it has a substantially truncated pyramid shape. Partition 3 in outer shell 3a of kneaded material supply unit 3
b are formed, and two clay supply holes 4 and 5 are formed by the outer shell 3a and the partition 3b.

The clay supply unit 2 has substantially the same form as the clay supply unit 3. That is, the clay supply unit 2 has a substantially truncated pyramid shape, and the partition 2b is formed in the outer shell 2a of the clay supply unit 2, and the outer shell 2a and the partition 2b
Thereby, two clay supply holes 8 and 9 are formed.

The respective clay supply units 2 and 3 are connected to the outer shell of the base body 10. The kneaded material supply holes 8 and 9 of the kneaded material supply unit 2 communicate with the forming holes 10 a of the die body 10, and the kneaded material supply holes 4 and 5 of the kneaded material supply unit 3 are connected to the die body 10.
In the forming hole 10b. Forming holes 10a and 10b
Are separated from each other by a partition 10f. On the outlet side of the base body 10, the forming holes 10a and 10b merge toward one forming hole 10d.

The base 1 is attached to a molding cylinder (not shown). By driving a kneaded material transfer mechanism in the forming cylinder, preferably a plunger, a predetermined kneaded material can be supplied into each of the kneaded material supply holes 4, 5, 8 and 9.

More specifically, the clay supply hole 8 of the clay supply unit 2
The kneaded clay 13A for the fuel electrode is continuously supplied, and the kneaded clay 14A for the solid electrolyte layer is continuously supplied to the kneaded clay supply hole 9. At the same time, the kneaded material 15A for the air electrode is continuously supplied to the kneaded material supply hole 4 of the kneaded material supply unit 3, and the kneaded material for the conductive dense body layer is supplied to the kneaded material supply hole 5. 16A is supplied continuously.

The clay 1 for the fuel electrode flowing through the clay supply hole 8
3A and the clay 14A for the solid electrolyte layer flowing in the clay supply hole 9 are discharged from the clay supply unit 2 and
Continuously flows into the molding hole 10a, and merges at a junction A on the inlet side of the molding hole 10a. At this time, the cross-sectional area of the forming hole 10a is smaller than the cross-sectional area of the kneaded clay supply holes 8 and 9, and when the kneaded clays 13A and 14A merge, the cross-sectional area of the forming hole 10a is greatly increased. High pressure is applied, and as a result, the clay 13B and 14B come to strongly press each other. In this state, the clays 13B and 14B are formed with the forming holes 10a.
It flows toward the junction D through the inside.

Also, the clay 15A flowing through the clay supply hole 4
And the kneaded clay 16A flowing through the kneaded clay supply hole 5 are discharged from the kneaded clay supply unit 3, continuously flow into the forming hole 10b of the die body 10, and meet at the entrance side of the forming hole 10b. Merge at B. At this time, the cross-sectional area of the forming hole 10b is smaller than the cross-sectional area of the kneaded clay supply holes 4 and 5, and when the kneaded clays 15A and 16A merge, the cross-sectional area of the forming hole 10b is greatly increased. Pressure is applied, and as a result, the clay 15B and 1
6B are strongly pressed against each other. In this state, the clay 15B and 16B flow toward the junction D in the forming hole 10b.

FIG. 3 shows the state of the cross section at this time. In this state, the clay 13B, 14B and the clay 15B, 16B
Are still partitioned by the partition 10f. A predetermined number (three in this drawing) of cores 11 are provided in the molding holes 10b. The cross-sectional shape of each core 11 is substantially square or rectangular, respectively, and corresponds to each gas flow path 24 of the unit cell 21 shown in FIG.

Each core 11 extends to the end of the forming hole 10b of the die body 10, that is, to the junction B between the clays 15A and 16A.

Each clay 13B, 14B, 15B and 16
B flows through each of the forming holes 10a and 10b toward the outlet 10e of the die body 10, and merges at a merge point D. FIG.
Indicates the state of each kneaded clay after the merging. By this merging, the clay 13C, 14C, 15C and 16C
Are laminated as shown in FIG.
d, flows toward the exit 10e and exits 10e
Is discharged from

In the compact 21 of the unit cell thus manufactured, the compact 16D of the conductive dense layer, the compact 15D of the air electrode, the unsintered solid electrolyte layer 14D and the unsintered fuel electrode 13D are mutually connected. Closely adhered and laminated. The molded body 16D is rectangular in a plan view, and has a partition wall 16a and a groove 25 formed to extend along its long side. In addition, the air electrode formed body 15D has a planar view.
It has almost the same shape as the molded body 16D. The partition wall 15a and the groove 22 are formed so as to extend along the long side of the molded body 15D. The number of these grooves and partitions can be variously changed. Preferably, a radius is formed at each corner of each groove 22, 25.

An oxidizing gas channel 24 is formed by the pair of grooves 22 and 25 facing each other. The interface 23 between the partition walls 15a and 16a is connected to the side surface 24a of each oxidizing gas flow path 24.

An unsintered solid electrolyte layer 14a is formed so as to cover the upper side surface of the formed body 15D of the air electrode, and an unsintered solid electrolyte layer 14b is formed so as to cover the side surface of the formed body 15D. ing. Solid electrolyte layers 14a, 14b
The unfired fuel electrodes 13a and 13b are formed on the substrate. The surface 13c of the side fuel electrode 13b is
And is continuous with the side surface 16b without a step. This is because the wall surface 18 of the forming hole 10d is flat as shown in FIG. In the unit cell that can be manufactured according to this embodiment, the side surface 16b of the dense body layer 16D and the side surface 13c of the fuel electrode 13D are continuous without any step, but this is not necessary.

When the laminated compact 21 is fired, the compacts 16D and 14D are densified, and the oxidizing gas flow path 24 is isolated from the atmosphere outside the cell.

FIG. 6 shows a base 31 used in another embodiment.
FIG. 7 is a cross-sectional view showing a laminated molded body 33 manufactured using the die of FIG.

The base 31 includes a base body 36 and a pair of clay supply units 3 and 37. The kneaded material supply unit 3 is shown in FIG.
2 and FIGS. 2A, 2B, and 2C. The kneaded material supply unit 37 has a substantially quadrangular pyramid shape, and one kneaded material supply hole 35 is formed in the outer shell of the kneaded material supply unit 2.

The respective clay supply units 3 and 37 are connected to the outer shell of the base body 36. The kneaded material supply hole 35 of the kneaded material supply unit 37 communicates with the forming hole 36a of the die body 36, and the kneaded material supply holes 4 and 5 of the kneaded material supply unit 3 are connected to the die body 36.
Of the molding hole 36b. Forming holes 36a and 36b
Are separated from each other by a partition 36f. On the outlet side of the base body 36, the forming holes 36a and 36b merge toward one forming hole 36d.

The die 31 is also attached to a forming cylinder (not shown), and by driving a kneading material transfer mechanism in the forming cylinder, a predetermined kneading material is supplied to each of the kneading material supply holes 4, 5, 3.
5 can be supplied.

The kneaded clay 14A for the solid electrolyte layer flowing through the kneaded clay supply hole 35 is discharged from the kneaded clay supply unit 37 and continuously flows into the forming hole 36a of the die body 36. The diameter of the kneaded material supply hole 35 gradually decreases as it approaches the die body 36, and the diameter of the forming hole 36a is
It becomes smaller gradually as it approaches.

The kneaded clay 15A flowing through the kneaded clay supply hole 4 and the kneaded clay 16A flowing through the kneaded clay supply hole 5 are discharged from the kneaded clay supply unit 3 and continuously formed in the forming holes 36b of the die body 36. And merges at a junction B on the inlet side of the forming hole 36b. At this time, compared with the cross-sectional area of the kneaded material supply holes 4 and 5,
The cross-sectional area of the forming hole 36b is small, and the clay 15A
When the and 16B merge, a large pressure is applied in the cross-sectional direction of the forming hole 36b, and as a result, the clay 15B and 16B are strongly pressed to each other. In this state, the clay 15B
And 16B flow toward the junction D in the forming hole 36b. The state of the cross section at this time is shown in FIG.

Each of the clays 14B, 15B and 16B passes through each of the forming holes 36a and 36b through the outlet 36e of the die body 36.
And merge at the junction D. By this merging, the clays 14C, 15C and 16C are stacked as shown in FIG. 4 (excluding the fuel electrode clay), and in this state, flow through the forming hole 36d toward the outlet 36e.
It is discharged from the outlet 36e.

In the laminated molded body 33 thus manufactured, the molded body 16D of the conductive dense layer, the molded body 15D of the air electrode, and the unsintered solid electrolyte layer 14D are closely adhered and laminated. The molded body 16D is rectangular in plan view, and the partition 16a extends along the long side thereof.
And a groove 25 are formed. Further, the partition wall 15a and the groove 22 are formed so as to extend along the long side of the molded body 15D.

An oxidizing gas flow path 24 is formed by the pair of grooves 22 and 25 facing each other. The interface 23 between the partition walls 15a and 16a is connected to the side surface 24a of each oxidizing gas flow path 24.

An unsintered solid electrolyte layer 14a is formed so as to cover the upper side surface of the air electrode formed body 15D, and an unsintered solid electrolyte layer 14b is formed so as to cover the side surface of the formed body 15D. ing. The surface 14c of the side solid electrolyte layer 14b is continuous with the side surface 16b of the molded body 16D without any step. However, the side surface 16b of the dense body layer 16D and the side surface 14c of the solid electrolyte layer 14D need not be continuous without any step.

When the laminated compact 33 is fired, the compacts 16D and 14D are densified and isolated so that the oxidizing gas flow path 24 does not come into contact with the atmosphere outside the unit cell.

In the present invention, when an aqueous binder is used as the clay, it is not necessary to perform an exhaust treatment as in the case of using an organic solvent, so that the equipment can be simplified, and the laminated molded body extruded from the die can be formed. It becomes difficult to bend. In this case, the water content is more preferably set to 10 to 20% by weight. Examples of the aqueous binder include polyvinyl alcohol, methyl cellulose, and ethyl cellulose.

The main raw material of the conductive dense layer is preferably a lanthanum-containing perovskite composite oxide, more preferably lanthanum chromite.
This is because it has heat resistance, oxidation resistance, and reduction resistance.
Further, the clay constituting the green compact of the conductive dense body layer can be produced by mixing an organic binder and water with the main raw material. Examples of the organic binder include polymethyl acrylate, nitrocellulose, polyvinyl alcohol, methyl cellulose, ethyl cellulose, starch, wax, acrylic acid polymer and methacrylic acid polymer. When the weight of the main raw material is 100 parts by weight, the amount of the organic binder to be added is preferably 0.5 to 5 parts by weight.

The main raw material of the cathode is preferably a perovskite-type composite oxide containing lanthanum, more preferably lanthanum manganite or lanthanum cobaltite, and more preferably lanthanum manganite. Lantern Chromite and Lantern Manganite
It may be doped with strontium, calcium, chromium (in the case of lanthanum manganite), cobalt, iron, nickel, aluminum or the like. As the main raw material of the fuel electrode, nickel, nickel-zirconia mixed powder is preferable.

The kneaded material constituting the electrode compact can be produced by mixing an organic binder, a pore former and water with the main raw material of the electrode. Examples of the organic binder include those for the dense body described above. When the weight of the main raw material is 100 parts by weight, the amount of the organic binder to be added is preferably 0.5 to 5 parts by weight.

As the material for the solid electrolyte layer, yttria-stabilized zirconia or yttria partially-stabilized zirconia is preferable, but other materials can also be used.

[0052]

EXAMPLES Hereinafter, more specific experimental results will be described. Example 1 A single cell of a solid oxide fuel cell was manufactured in accordance with the method described with reference to FIGS.
Specifically, the following kneaded clay was first manufactured.

(Kneaded clay 13A for fuel electrode) Average particle size 5 μm
To a mixed powder of 60 parts by weight of nickel oxide powder and 40 parts by weight of 8 mol% yttria-stabilized zirconia powder, 4 parts by weight of cellulose, part by weight of methyl cellulose and polyvinyl alcohol were mixed. 14 parts by weight of water was added to this mixture, and a kneaded product was obtained using a kneader. This kneaded material is housed in a vacuum kneader and has a diameter of 50 m.
m, a columnar kneaded clay having a length of 300 mm was produced.

(Clay 14A for Solid Electrolyte Layer) 8 mol% Yttria-Stabilized Zirconia Powder 1 having an Average Particle Size of 2 μm
With respect to 00 parts by weight, 2 parts by weight of methylcellulose and polyvinyl alcohol were mixed. 14 parts by weight of water was added to this mixture, and a kneaded product was obtained using a kneader. This kneaded material is housed in a vacuum kneader and has a diameter of 50 m.
m, a columnar kneaded clay having a length of 300 mm was produced.

(Kneaded clay 15A for air electrode) Average particle size 3 μm
100 parts by weight of lanthanum strontium manganite powder, 4 parts by weight of methylcellulose, 7 parts of cellulose
Parts by weight, 2 parts by weight of carbon and polyvinyl alcohol were mixed. 21 parts by weight of water was added to this mixture, and a kneaded product was obtained using a kneader. The kneaded material was accommodated in a vacuum kneader to produce a cylindrical kneaded material having a diameter of 50 mm and a length of 300 mm.

(Clay 16A for Dense Body Layer) Average Particle Size 3 μm
3 parts by weight of methylcellulose and 100 parts by weight of lanthanum chromite powder of m were mixed with polyvinyl alcohol. 14 parts by weight of water are added to this mixture,
A kneaded material was obtained using a kneader. The kneaded material was accommodated in a vacuum kneader to produce a cylindrical kneaded material having a diameter of 50 mm and a length of 300 mm.

By adjusting the amount of polyvinyl alcohol to be added to each of the above clays, the difference in hardness between the respective clays was made ± 1.

Using the extrusion molding apparatus shown in FIGS.
According to the method described above, the laminated molded body 21 shown in FIG. 5 was manufactured. At this time, the hydraulic pressure of the plunger was controlled such that the extrusion speeds of the respective clays were substantially the same, thereby preventing bending of the laminated molded body.

The laminate 21 was placed in a thermo-hygrostat dryer and dried at 80 ° C. After drying, the dried laminate was placed in an electric furnace and heated at a rate of 40 ° C./hour to 1550 ° C.
The temperature was raised to 1,550 ° C. for 4 hours, and the cells were integrally sintered to produce a unit cell. The external dimensions of this sintered body were 7 mm long, 21 mm wide and 50 mm long. The dimensions of the cross section of each oxidizing gas channel were 3 mm long and 3 mm wide.

A heat cycle test was performed on this single cell. That is, the temperature of the unit cell is increased from room temperature at a rate of 200 ° C./hour, and is maintained at 1200 ° C. for 30 minutes.
The temperature was lowered from 0 ° C. at 200 ° C./hour and kept at 100 ° C. for 30 minutes. This temperature rise-fall cycle between 1200 ° C. and 100 ° C. was repeated, and finally cooled to room temperature to check for cracks. The test was performed on a total of 10 samples. As a result, no crack was observed even after 20 heat cycles.

Further, a power generation experiment was performed using this unit cell. The cell was held by a ceramic manifold, and nickel felt was used as a current collector. Pyrex glass was used for a gas seal portion between the manifold and the unit cell. This Pyrex glass melts under a power generation condition of 1000 ° C. and exhibits a gas sealing function. Hydrogen humidified through a room temperature bubbler was used as fuel gas, and air was used as oxidizing gas. The air was supplied to the air electrode through the oxidizing gas passages of the manifold and the unit cell. Hydrogen was supplied to the fuel electrode side by flowing around the cell.

Under these power generation conditions, the internal resistance of the cell was measured by the complex impedance method. The power generation current was 300 mA / cm ² per unit area of the fuel electrode. Each internal resistance was measured at the initial stage of power generation and after 100 hours of continuous power generation, and changes in internal resistance and the presence or absence of cracks in the unit cells were observed. As a result, no peeling or cracking was observed even after continuous power generation for 100 hours. The initial internal resistance was 0.25 Ω · cm ² , and the internal resistance after 100 hours of power generation was 0.26 Ω · cm ² .

The polarization value of the cell of the present invention thus obtained is
Current density 100 mA / cm ² , 200 mA / cm ² , 3
As a result of measurement at 00 mA / cm ² , respectively, 22 mV,
It was 41 mV and 53 mV. Thus, it was found that the polarization value was small. This is considered to be due to the fact that the materials were appropriately mixed at the interface between the electrode and the electrolyte, and the three-layer interface effective for the reaction was widened. Also, the adhesion strength has been improved,
It is considered that the separation of the interface became difficult to occur.

[Comparative Example 1] In the same manner as in Example 1, a kneaded clay 15A for the air electrode and a kneaded clay 16A for the dense body layer were manufactured, and each kneaded clay was extruded from the same die for extrusion molding. It was molded to obtain a laminated molded article. This laminated molded body was housed in a thermo-hygrostat and dried at 80 ° C. After drying, the dried laminate was placed in an electric furnace and heated at a rate of 40 ° C./hour to 1550 ° C.
The temperature was raised to 1550 ° C. for 4 hours, and the whole was sintered to obtain a substrate.

On this substrate, the above-mentioned powder composed of the above-mentioned raw material for a solid electrolyte was subjected to plasma spraying, and this was heat-treated to form a solid electrolyte membrane. Then, a paste made of the above-mentioned fuel electrode raw material was screen-printed thereon to form a film, and this was heat-treated to form a fuel electrode film. Thus, a cell of Comparative Example 1 was obtained. The external dimensions of this unit cell and the dimensions of the cross section of each oxidizing gas flow path are the same as those in the first embodiment.

The polarization value of the cell of Comparative Example 1 was determined by measuring the current densities of 100 mA / cm ² , 200 mA / cm ² and 300 m / cm ² .
A / cm ² , 40 mV, 62 m
V, 92 mV.

Example 2 A cell was manufactured in the same manner as in Example 1. However, the above-mentioned fuel electrode is a cathode, and the air electrode is an anode. Using this cell, 1
Steam electrolysis was performed at 000 ° C. 5.6% H ₂ O was supplied to the cathode (nickel-zirconia cermet) side using helium containing 0.5% hydrogen as a carrier gas. Air was supplied to the anode (lantern manganite side). At this time, the end of the cell was sealed with glass to the gas supply manifold so that the gas on the cathode side and the gas on the anode side did not mix with each other.

As a result of measuring a current density as a steam electrolysis characteristic, a current density of 250 mA / cm ² or more at 1.5 V was obtained. At this time, the amount of generated hydrogen was measured using a gas chromatograph, and as a result, a hydrogen generation amount of about 14 cc / min was obtained. Thus, it was confirmed that generation of hydrogen by steam electrolysis was possible.

Further, the polarization value of the cell of Example 2 was measured at a current density of 50 mA / cm ² , 100 mA / cm ² , 150 mA.
/ Cm ² , 200 mA / cm ² , and the results were 160 mV, 200 mV, 300 mV, 410 mV
Met.

Comparative Example 2 A cell was manufactured in the same manner as in Comparative Example 1. However, the above-mentioned fuel electrode is a cathode, and the air electrode is an anode. The polarization value of this cell is determined by the current density of 50
mA / cm ² , 100 mA / cm ² , 150 mA / cm
² and 200 mA / cm ² , respectively.
0 mV, 360 mV, 420 mV, and 550 mV.

[0071]

As described above, according to the present invention, the solid electrolyte layer, one electrode and the other electrode formed on both sides of the solid electrolyte layer, and one electrode are integrated. When manufacturing an electrochemical cell having a dense body layer, the electrode and the solid electrolyte layer, and the adhesion between the electrode and the dense body layer can be improved, the polarization at these interfaces can be reduced, and A production method with high productivity can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a die for extrusion molding that can be suitably used in the production method of the present invention, which is cut along a length direction thereof.

FIG. 2A is a front view showing an entrance side of the clay supply unit 3, and FIG. 2B is a side view of the clay supply unit 3,
(C) is a front view showing a state in which the clay supplying unit 3 is viewed from an exit side.

FIG. 3 is a sectional view of the base 1 in FIG. 1 taken along line III-III.

FIG. 4 is a sectional view of the base 1 of FIG. 1 taken along line IV-IV.

5 is a laminated molded body 21 obtained by the die 1 of FIG.
FIG.

FIG. 6 is a cross-sectional view of a die for extrusion molding that can be suitably used in a manufacturing method according to another embodiment of the present invention, which is cut along a length direction thereof.

7 is a cross-sectional view showing a laminated molded body 33 obtained by the base 31 shown in FIG.

[Explanation of symbols]

1, 31 base 2, 3, 37 kneaded clay supply unit 4,
5, 8, 9, 35 Kneaded clay supply hole 10, 36 Base body 10a, 10b, 10d, 36a, 36b, 36
d Forming hole 10f Partition between forming holes 10a and 10b 11 Core 13A Clay for fuel electrode 13B,
14B Clay 13C in forming holes 10a and 36a
14C, 15C, 16C Clay downstream of junction D
13D Unfired fuel electrode 14A Clay for solid electrolyte layer 14D Unfired solid electrolyte layer 15A
Clay for air electrode 15B, 16B forming holes 10b, 36
Clay in b 15D Molded body of air electrode 16A Clay for conductive dense body layer 16D Molded body of conductive dense layer 21 Laminated molded body of unit cell 24 Oxidizing gas channel 33 Laminated molded body A Fuel Junction point B of pole body 13A and solid electrolyte layer body 14A
Clay 15A for solid electrolyte layer and Clay 16 for dense body layer
Confluence with A D Final confluence

Claims (3)

[Claims] An electrochemical cell comprising a solid electrolyte layer, one electrode and the other electrode formed on both sides of the solid electrolyte layer, and a dense layer integrated with the one electrode. The method for manufacturing, the fill for forming the one electrode, and the fill for forming the dense body layer, in the die while continuously extruding separately, and then merged, By merging on the one electrode in the base while continuously extruding the fill for forming the solid electrolyte layer,
A method for producing an electrochemical cell, comprising obtaining a laminated molded body including at least the molded body of the dense body layer, the molded body of the one electrode, and the molded body of the solid electrolyte layer. 2. Filling clay for forming said one electrode,
The fill for forming the dense layer is joined together in a die while continuously and separately extruding, and then the fill for forming the solid electrolyte layer and the other electrode are formed. The method for manufacturing an electrochemical cell according to claim 1, wherein the kneaded material is joined to the one electrode in the die while continuously extruding the kneaded material in a stacked state. 3. A method for manufacturing an electrochemical cell in which a gas flow path extending in a direction in which each fill is extruded is formed between the dense body and the one electrode. The groove for forming the gas flow path is formed before or at the same time as the fill for forming the first electrode and the fill for forming the one electrode merge. 3. The method for producing an electrochemical cell according to 1 or 2.