JP2003317738A - Method for manufacturing fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fuel cell, capable of keeping the percentage of contraction by sintering within a proper range when manufacturing a cylindrical solid electrolyte fuel cell, securing the denseness for an electrolyte film and an inter-connector, and enhancing a fuel utilization factor. <P>SOLUTION: Each of the electrolyte film and the inter-connector preferably satisfies at least one or two of conditions (a)-(c). (a) It contains a coarse particle and a fine particle having mutually different particle diameters, and 0-50% of the coarse particle is added to the fine particle. (b) The ratio (R/r) of the particle diameter (R) of the coarse particle to the particle diameter (r) of the fine particle is 4≤(R/r)≤30. (c) The particle diameter (r) of the fine particle is 0.1≤r≤1. When the conditions (a)-(c) are all satisfied, its relative density becomes 92-98%, and its percentage of contraction by sintering becomes 8-17%. <P>COPYRIGHT: (C)2004,JPO

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 a fuel cell, and more particularly to a material used when manufacturing a fuel cell.

[0002]

2. Description of the Related Art A technique relating to a method for forming a lanthanum chromite dense thin film is described in JP-A-9-263961.

A method for forming a dense thin film of lanthanum chromite on a porous ceramic substrate includes a total of five steps, a first step to a fifth step. The first step is a step of preparing a lanthanum chromite powder (coarse powder) having an average particle size of 1 to 2 μm and a lanthanum chromite powder (fine powder) having an average particle size of 0.1 to 0.2 μm by pulverization and classification.
In the second step, the obtained powder is converted into a coarse powder: fine powder ratio (wt%).
It is a step of mixing at a ratio of 90:10 to 50:50.

In the third step, the mixed powder is used as a binder.
This is a step of obtaining a slurry by mixing with a solvent or the like. The fourth step is a step of forming a lanthanum chromite film on the porous ceramic substrate using the slurry. The fifth step is a step of sintering the formed lanthanum chromite film.

The chemical composition of the above lanthanum chromite is L
a _(1-x) Ca _x CrO ₃ , and the sintering temperature is 13
It is 00-1500 degreeC. The porous ceramic substrate is an air electrode of a polymer electrolyte fuel cell, and the lanthanum chromite dense thin film is an interconnector. The porous ceramic substrate is made of lanthanum manganite and has an average pore diameter of 0.05 to 10 μm.

Next, the fuel cell manufacturing method 10a of the present invention.
A conventional technique related to the above will be described. The fuel cell 10 mainly targeted in the present invention is a solid oxide fuel cell (hereinafter referred to as “SOFC”). SOFCs are classified into cylindrical SOFCs and flat plate SOFCs.
The FC is further classified into a horizontal striped type and a vertical striped type according to the difference in its structure.

In the production of a cylindrical SOFC, whether it is a horizontal striped type or a vertical striped type, first, a fuel electrode material film, an electrolyte membrane material film, an interconnector material film, and an air electrode material film are formed on a substrate tube. Is formed using a method such as a screen printing method or a dipping method. After that, a method of forming each element of the fuel electrode, the electrolyte membrane, the interconnector, and the air electrode on the base pipe by performing integral sintering is performed.
However, in the production of the horizontal cylindrical SOFC, first, the air electrode material film is not integrally formed but is integrally sintered, and then the air electrode material film is formed and sintered to form the air electrode. May be formed.

[0008] Each element contracts due to sintering, and the contraction causes the electrolyte membrane and the interconnector to be densified. The densification makes it possible to minimize the gas permeation of the fuel gas and the oxidant gas. In order to achieve this densification, it is necessary that the relative density with respect to the electrolyte membrane and the interconnector be 92% or more, and as a result, the shrinkage rate due to sintering with respect to the cylindrical SOFC in which each element is formed is , 18 to 22%.

Therefore, the contraction rate for the fuel electrode and the air electrode is about the same as the contraction rate for the electrolyte membrane and the interconnector. However, when the contraction rate for each of the fuel electrode and the air electrode is 18 to 22%, the diffusion resistance of the fuel gas or the oxidant gas at those electrodes becomes very large. Therefore, as a result, the progress of the fuel cell reaction is hindered, and the utilization rates of the fuel gas and the oxidant gas (hereinafter, referred to as “fuel utilization rate”) are reduced, and the output density in power generation is reduced.

On the other hand, in the manufacture of flat plate type SOFC,
(1) In some cases, the material film for the electrolyte membrane (or the material film for the interconnector) is independently formed, and the formed material film for the electrolyte membrane (or the material film for the interconnector) is sintered. In some cases, (2) the air electrode material film, the electrolyte film material film, the interconnector material film, and the fuel electrode material film are formed and integrally sintered. In both cases of (1) and (2), if the shrinkage ratio during sintering is larger than an appropriate value, uneven contraction may occur due to restraint of the supporting surface during sintering, and deformation may occur. . This deformation causes a reduction in the contact area between the respective elements formed by sintering and a reduction in the sealability, resulting in a reduction in the power density during power generation and a reduction in the fuel utilization rate.

Therefore, conventionally, a sintered flat plate type SOF is used.
The straightening process was performed by placing a weight on the deformed portion of C (or around it) and heat-treating it. However, the increase in manufacturing cost due to the correction process has been a problem.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel cell capable of ensuring compactness with respect to an electrolyte membrane and an interconnector by suppressing the shrinkage rate due to sintering of a cylindrical SOFC within an appropriate range. It is to provide a manufacturing method of.

Another object of the present invention is to provide a method of manufacturing a fuel cell capable of improving the fuel utilization rate by suppressing the shrinkage rate due to sintering of a cylindrical SOFC within an appropriate range. .

Still another object of the present invention is a flat plate type SOFC.
It is an object of the present invention to provide a method for manufacturing a fuel cell, which can reduce the need for a straightening treatment after firing by minimizing the shrinkage rate due to sintering.

Still another object of the present invention is a flat plate type SOFC.
It is an object of the present invention to provide a method for manufacturing a fuel cell capable of improving the fuel utilization rate and the power density by minimizing the shrinkage rate due to the sintering.

Still another object of the present invention is to provide a fuel cell manufactured by the above manufacturing method.

[0017]

[Means for Solving the Problems] The means for solving the problems will be described below by using the numbers and symbols used in [Embodiment of the Invention] in parentheses. These signs are
Although added to clarify the correspondence between the description of [Claims] and the description of [Embodiment of the Invention], the technical scope of the invention described in [Claims] is added. It should not be used to interpret ranges.

Method for producing fuel cell of the present invention (10a)
Is a step (S1) of forming a base tube (11), and a fuel electrode (20) and an electrolyte membrane (2) on the base tube (11).
1), steps of forming an air electrode (22) (S3, S
4 and S5). The material of the electrolyte membrane (21) includes first particles (AA) and second particles (BB), and the content ratio of the first particles (AA) is 10 to 50 vo.
1%. The ratio of the particle size of the first particles (r1) to the particle size of the second particles (r2) is 4 ≦ (r1 / r2).
≦ 30. The step of forming (S3, S4, S5) includes forming a fuel electrode material film, an electrolyte membrane material film, and an air electrode material film on the base pipe (11).
The formed fuel electrode material film, electrolyte membrane material film, and air electrode material film are sintered to form the fuel electrode (20), the electrolyte membrane (21), and the base electrode (11) on the base tube (11). Including the step of forming the cathode (22), the formed electrolyte membrane (21) has a relative density of 92 to 98%. The contraction rate of the material film for the electrolyte membrane due to sintering is 8 to 17%.
Is.

The step of forming (S3, S4, S5) includes the step of forming an interconnector material film on the base pipe (11). (S3, S
4, S5) forming step includes the step of sintering the material film for interconnector to form the interconnector (23) on the base tube (11), and baking on the base tube (11). The relative density of the interconnected connectors (23) is 92 to 98%. The shrinkage rate of the material film for interconnector due to sintering is 8 to 17%.
The material of the interconnector (23) is the third particle (C
C) and fourth particles (DD), and the third particles (C
The content rate of C) is 10 to 50 vol%. The third
The particle size of the particles (r3) and the particle size of the fourth particles (r3
The ratio with 4) is 4 ≦ (r3 / r4) ≦ 30.

Method for producing fuel cell of the present invention (10a)
Is a step (S1) of forming a base tube (11), and a fuel electrode (20) and an electrolyte membrane (2) on the base tube (11).
1), steps of forming an air electrode (22) (S3, S
4 and S5). The material of the electrolyte membrane (21) contains first particles (AA) and second particles (BB), and the particle diameter (r1) of the first particles (AA) and the second particles (BB) The ratio with the particle size (r2) is 4 ≦ (r1
/ R2) ≦ 30. The step of forming (S3, S4, S5) includes forming a fuel electrode material film, an electrolyte membrane material film, and an air electrode material film on the base tube (11), and forming the fuel electrode. The base material tube (11) obtained by sintering a material film for electrolyte, a material film for electrolyte membrane, and a material film for air electrode.
The step of forming the fuel electrode (20), the electrolyte membrane (21), and the air electrode (22) on the upper side, the relative density of the formed electrolyte membrane (21) is 92 to 98%. The contraction rate of the material film for the electrolyte membrane due to sintering is 8 to
17%.

The step of forming (S3, S4, S5) includes the step of forming an interconnector material film on the base pipe (11). The material of the interconnector (23) contains third particles (CC) and fourth particles (DD), and the particle diameter (r of the third particles (CC) is
The ratio of 3) to the particle diameter (r4) of the fourth particles (DD) is 4 ≦ (r3 / r4) ≦ 30. (S3, S
4, S5) the step of forming includes the step of sintering the material film for interconnector formed on the base pipe (11) to form the interconnector (23), and the formed interconnector ( The relative density of 23) is
It is 92 to 98%. The shrinkage rate of the material film for interconnector due to sintering is 8 to 17%.

The fuel cell (10) of the present invention includes a cylindrical horizontal stripe type solid electrolyte type fuel cell and a cylindrical vertical stripe type solid electrolyte type fuel cell, and these fuel cells (10) are manufactured by the above manufacturing method. Is manufactured using.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) FIG. 1 shows the structure of a cylindrical horizontal stripe SOFC. Further, FIG. 2 shows the structure of a cylindrical vertical stripe SOFC. Each of these cylindrical SOFCs has a base tube 11 and a fuel electrode 20, an electrolyte membrane 21, an air electrode 22 and an interconnector 2 formed on the base tube 11.
It is composed of a plurality of fuel cell units 19 each having three elements. The cylindrical horizontal stripe type SOFC and the cylindrical vertical stripe type SOFC differ in the formation order of each element on the base tube 11.
The horizontal cylindrical SOFC has a structure in which the fuel electrode 20,
The electrolyte membrane 21 and the air electrode 22 are formed in this order, and the interconnector 23 is configured to connect the fuel electrode 20, the electrolyte membrane 21, and the air electrode 22 included in different fuel cell units 19 to each other. The cylindrical vertical stripe type SOFC has an air electrode 22, an electrolyte membrane 21, and a fuel electrode 2 from the surface of the substrate tube 11.
They are formed in the order of 0, and the interconnector 23 includes an air electrode 22 and an electrolyte membrane 2 which are included in different fuel cell parts 19.
1. The fuel electrode 20 is configured to be connected to each other. The material for each of the electrolyte membrane 21 and the interconnector 23 preferably satisfies the conditions (a) to (c) described later (at least any one or two).

In manufacturing the fuel cell 10 (cylindrical SOFC), as the material of the electrolyte membrane 21, particles having a relatively small particle size (fine particles BB) and particles having a relatively large particle size (coarse particles AA) are used. By using an appropriate amount added, it is possible to suppress the shrinkage rate during sintering, as compared with the case where only the fine particles BB are used. By suppressing the contraction rate, it becomes possible to suppress an increase in gas diffusion resistance in the fuel electrode 20 and the air electrode 22. However, when the contraction rate is very low, the fuel utilization rate decreases due to gas permeation through the electrolyte membrane 21.

Therefore, in order to keep the shrinkage ratio within an appropriate range, first consider the relative density of each of the electrolyte membranes 21. The relative density is the relative ratio of the density of a certain substance to the density of pure water at 4 ° C., and is calculated using the following equation (1) for each electrolyte membrane 21. (Density of electrolyte membrane 21 / Density of pure water at 4 ° C.) × 100 (1)

The relative density calculated using the equation (1) is
This indicates the degree of densification of the electrolyte membrane 21 due to sintering. If the relative density exceeds the appropriate range, the fuel electrode 2
0 and the diffusion resistance of the gas in the air electrode 22 increase, and the fuel utilization rate decreases. On the other hand, when the relative density is below the appropriate range, the fuel utilization rate decreases due to gas permeation through the electrolyte membrane 21. Therefore, in order to prevent the fuel utilization rate from decreasing, the material may be prepared so that the relative density of the electrolyte membrane 21 falls within an appropriate range. From this viewpoint, a plurality of types of materials for the electrolyte membrane 21 were prepared, and an experiment was conducted using each of these materials. The result is shown in FIG.

In FIG. 3, test number 3a, fine particle diameter 3b, coarse particle diameter 3c, fine particle amount 3d, coarse particle amount 3e, shrinkage rate 3f, electrolyte membrane relative density 3g, output density 3h, maximum fuel utilization rate 3i is shown. Fine particle size 3b, coarse particle size 3
c indicates the particle size of the fine particles BB or the coarse particles AA used for each material corresponding to the test number 3a. Fine particle amount 3d,
The coarse particle amount 3e indicates the content rates of the fine particles BB and the coarse particles AA with respect to the material of the electrolyte membrane 21, respectively.

The experimental method will be described below. First, the electrolyte membrane
As the material of No. 21, the material corresponding to each of the test numbers 3a
Using the fuel cell 10 (including the interconnector 23
A cylindrical horizontal stripe type SOFC) was manufactured. Then the fuel
Power generation test at 900 ° C using hydrogen as fuel using the battery 10.
Tested, 200mA / cm^TwoPower density at 3h
And the maximum fuel utilization rate 3i was calculated. Also, for power generation test
After that, the resin-filled and polished sample is observed under an optical microscope to obtain an image.
The density of the electrolyte membrane 21 was obtained by analysis. Furthermore,
Of the electrolyte membrane relative density of 3 g based on the density of
The degree of densification of the electrolyte membrane 21 was calculated and examined. To the material
Is 8 mol% Y as the electrolyte membrane 21._TwoO _ThreeFull stabilization
ZrO_TwoWas used. Base tube 11, fuel electrode 20, air electrode 2
2 is 15 mol% CaO containing 20% NiO.
Standardized ZrO_Two, 60% NiO and 40% YSZ, La
_0.6CaO_0.4MnO_ThreeOf each.

For test numbers 3a = 1 to 5, the fine particle size 3b (0.5 μm) and the coarse particle size 3c (8 μm) were unified, and the fine particle amount 3d (100 to 40%) was changed. Corresponds to the prepared material. When the amount of fine particles 3d is 100% (test number 3a = 1), the maximum fuel utilization rate 3i is 75%.
Which is lower than the test numbers 3a = 2 to 4. At this time, the electrolyte membrane relative density 3 g was 99% and the shrinkage ratio 3f was 20%.
It is considered that the problem of gas permeation from No. 1 has been solved. However, for the fuel electrode 20 and the air electrode 22, the gas (fuel gas,
It is considered that the diffusion resistance of the oxidant gas) has increased.

When the fine particle amount 3d is 40% (test number 3a
= 5), the maximum fuel utilization rate 3i is 72%,
Compared with the materials corresponding to each of the test numbers 1a = 1 to 4, the value remains low. At this time, the relative density of the electrolyte membrane 3g was 91.2% and the shrinkage rate 3f was 7.5%, and it is considered that the densification of the electrolyte membrane 21 has not progressed. Therefore, from the electrolyte membrane 21 It is conceivable that the maximum fuel utilization rate 3i has decreased due to the significant progress of gas permeation.

On the other hand, when the amount of fine particles 3d is 90 to 50% (test number 3a = 2 to 4), the maximum fuel utilization rate 3i is 80% or more. At these times,
The electrolyte membrane relative density of 3 g and the contraction rate of 3 f are within the ranges of 92 to 98% and 8 to 17% for all materials, respectively. Therefore, from the viewpoint of densification of the electrolyte membrane 21 and improvement of the fuel utilization rate, as the material of the electrolyte membrane 21, the blending amount is fine particles (vol%): coarse particles (vol%) = 90:10 to 5
It is considered desirable to set it to 0:50. Further, when compared among the test numbers 3a = 2 to 4, the fuel utilization rate 3i is particularly high when the test numbers 3a = 3 and 4, and therefore, the blending amount is fine particles (vol%): coarse particles (vol%). = 7
It is considered to be more desirable to set it in the vicinity of 0:30 to 50:50.

Test number 3a = 6 to 9 is a coarse grain size 3c
(8 μm) and the amount of fine particles 3d (70%) are unified, and the fine particle size 3b (0.08 to 1.5 μm) is changed to correspond to the prepared material. When the fine particle diameter 3b is 0.08 μm (test number 3a = 6), the maximum fuel utilization rate 3i is 70.
%, Which is lower than the test number 3a = 7 to 9. At this time, the electrolyte membrane relative density 3 g was 99% and the shrinkage ratio 3f was 25%.
It is considered that the gas permeation from 1 hardly progressed. However, it is considered that the densification of the fuel electrode 20 and the air electrode 22 greatly progressed, so that the gas diffusion resistance became extremely large.

When the fine particle diameter 3b is 1.5 μm (test number 3a = 9), the maximum fuel utilization rate 3i is 70%, which is lower than that when test number 3a = 6-8. Stays in. At this time, the electrolyte membrane relative density of 3 g is 99
%, And the shrinkage rate 3f is 25%, and it is considered that gas permeation from the electrolyte membrane 21 has hardly progressed.
However, with respect to the fuel electrode 20 and the air electrode 22, it is considered that the gas diffusion resistance increased because the densification proceeded greatly.

On the other hand, when the fine particle amounts 3d are 0.1 μm and 1 μm (test number 3a = 7, 8), the relative density of the electrolyte membrane is 3
g is 98% and 92.2%, respectively, and in these cases, the maximum fuel utilization rate 3i is within 80% or more (83%, 85%). Therefore, from the viewpoint of densification of the electrolyte membrane 21 and improvement of the fuel utilization rate, as a material used for the electrolyte membrane 21, the particle size (r) of the fine particles BB is 0.
It is considered desirable to set 1 μm ≦ r ≦ 1 μm. Further, comparing the test numbers 3a = 7 and 8, the fuel utilization rate 3i is relatively high when the test number 3a = 8,
Therefore, it is considered more desirable to set the particle size (r) of the fine particles BB to around 1 μm.

Test number 3a = 10 to 13 is fine particle size 3
b (0.5 μm) and the fine particle amount 3d (70%) are unified, and the coarse particle size 3c (1.5 to 20 μm) is changed to correspond to the prepared material. When the coarse particle size 3c is 1.5 μm (test number 3a = 10), the maximum fuel utilization rate 3i is 7
The value is 0%, which is a low value as compared with the test numbers 3a = 11 to 13. At this time, the electrolyte membrane relative density 3 g was 99% and the shrinkage rate 3f was 25%, and it is considered that gas permeation from the electrolyte membrane 21 has hardly progressed. However, with respect to the fuel electrode 20 and the air electrode 22, it is considered that the gas diffusion resistance increased because the densification proceeded greatly.

When the coarse particle diameter 3c is 20 μm (test number 3a = 13), the maximum fuel utilization rate 3i is 70%, which is lower than that when test number 3a = 10-12. It remains. At this time, the electrolyte membrane relative density 3 g was 87.3% and the shrinkage ratio 3f was 6.4%.
It is considered that the densification of No. 1 has not progressed, and for this reason, the gas permeation from the electrolyte membrane 21 has greatly progressed, and the maximum fuel utilization rate 3i has decreased.

On the other hand, when the coarse grain size 3c is 2 μm and 15 μm (test number 3a = 11, 12), the maximum fuel utilization rate 3i is 80% or more (81%, 83%). There is. Therefore, from the viewpoint of densification of the electrolyte membrane 21 and improvement of the fuel utilization rate, the grain size ratio (coarse grain size 3c / fine grain size 3b) rr is defined as the material used for the electrolyte membrane 21 by r
r = 4 (test number 3a = 11) to 30 (test number 3a =
It is considered desirable to set it to 12). Also,
Compared with test numbers 3a = 11 and 12, fuel utilization rate 3
i is relatively high when the test number 3a = 12, and therefore it is considered to be more desirable if the particle size ratio rr is set near 30.

From the experimental results shown in FIG. 3, the electrolyte membrane 21
It is considered that the desirable conditions for the material (1) to (3) are the following (a) to (c). (A) It contains coarse particles BB and fine particles AA having different particle diameters, and the content ratio of the coarse particles AA is 10 to 5.
It is 0%. (B) The ratio (R / r) of the particle size (R) of the coarse particles BB and the particle size (r) of the fine particles AA is 4 ≦ (R / r) ≦ 30.
Is. (C) The particle size (r) of the fine particles AA is 0.1 μm ≦
r ≦ 1 μm. When the conditions (a) to (c) are satisfied, the maximum fuel utilization rate 3i is improved as compared with the conventional one, and at this time, the electrolyte membrane relative density 3g is 92 to 98% and the shrinkage rate 3f is 7 to 18%. Become. However, the conditions (a) to (c) do not always have to be satisfied, and even when either one or two are satisfied, the maximum fuel utilization rate 3i is improved as compared with the conventional case. It is considered to be a thing.

Next, in order to investigate whether the conditions (a) to (c) hold regardless of the type of the electrolyte membrane 21,
An experiment was performed using a fuel cell 10 (cylindrical horizontal stripe type SOFC not including the interconnector 23) in which the material of the electrolyte membrane 21 was changed. The results of this experiment are shown in FIG.

FIG. 4 shows test number 4a, electrolyte membrane material 4
b, fine particle diameter 4c, coarse particle diameter 4d, particle diameter ratio 4e, fine particle amount 4f, coarse particle amount 4g, shrinkage rate 4h, electrolyte membrane relative density 4
i, power density 4j, and maximum fuel utilization rate 4k are included. In addition, based on the conditions (a) to (c), the fine grain size 4 was set for each electrolyte membrane 21 shown in test number 4a of FIG.
c, the fine particle amount 4f, and the particle size ratio rr are each 0.1 to 1 μm,
70% and 14 to 22.5 are set. Test number 4a
= 14, 3 mol% Y ₂ O ₃ partially stabilized ZrO ₂ , 1
Lanthanum gallate system for 5 and 16, 17 and 1
For No. 8, the ceria-based electrolyte membrane 21 is used.

At this time, regardless of the electrolyte membrane material 4b,
In both cases, the maximum fuel utilization rate of 4k is 80% or more.
It For these, the electrolyte membrane relative density 4i is 93
It is ~ 96%. Therefore, densification of the electrolyte membrane 21
And to achieve improved fuel utilization, the electrolyte membrane 21 seed
Regardless of type, conditions (a) to (c) above (at least
Also use the material prepared based on
Is considered desirable. Also, test number 4a
= 16 and 18, the maximum fuel utilization rate 4k is the highest,
Therefore, La_0.9Sr_0.1Ga_0.9Mg_0.1O
_Three, (CeO_Two) _0.8(SmO_1.5)_0.2Nozu
If any of them is used, it may be more desirable.

Next, in order to investigate whether the conditions (a) to (c) are satisfied for the interconnector 23 as well, the fuel cell 10 (cylindrical horizontal stripe SOFC) in which the material of the interconnector 23 is changed is investigated. , Cylindrical vertical stripe type SOFC). The material of the interconnector 23 is different from that of the electrolyte membrane 21, and the coarse particles CC and the fine particles DD are used.
Is included.

In FIG. 5, test number 5a, interconnector material 5b, fine particle diameter 5c, coarse particle diameter 5d, and fine particle amount 5 are shown.
e, coarse grain amount 5f, shrinkage rate 5g, interconnector relative density 5h, output density 5i, maximum fuel utilization rate 5j, and cell configuration 5k. Further, based on the conditions (a) to (c), the fine particle size 5c, the fine particle amount 5e, and the particle size ratio rr are set to 0.1 to 1 μm, 70%, and 5 to 19, respectively. Test number 5a = 19 and 20 are lanthanum chromite type,
Calcium titanate type interconnectors 23 are used for 21 and 22, respectively.

At this time, regardless of the interconnector material 5b, the maximum fuel utilization rate 5k is 80% or more in all cases. Therefore, in order to achieve the densification of the interconnector 23 and the improvement of the fuel utilization rate, the interconnector 2
It is considered preferable to use the materials prepared based on the conditions (a) to (c) (at least any one or two) regardless of the types. Further, when the test number 5a = 21, the maximum fuel utilization rate 5j is the highest,
Therefore, the use of Ca _0.9 La _0.2 TiO ₃ is considered to be more desirable.

From the results shown in FIGS. 3 to 5, the electrolyte membrane 2
1 and each material of the interconnector 23 satisfy the above conditions (a) to (c) (at least any one or two).
The fuel cell 10 (cylindrical SOFC) is manufactured by using the prepared material. Regarding the processing of the fuel cell manufacturing method 10a, FIGS.
Will be described with reference to.

A raw material of ceramic powder for the base tube 11 (such as zirconia powder) is mixed with an organic solvent (including additives) to form a uniform slurry, and a tubular ceramic molded body is formed by extrusion molding. The base tube 11 which is the above is molded (step S1). The base pipe 11 is a pipe in which the fuel cell unit 19 is formed, and is a cylindrical cylindrical pipe made of ceramics.

After molding, the base tube 11 is provided with a seal ring 14a.
Attach the seal cap 14b. Further, the base tube 11 is attached to the ceramic attachment portion 14 of the firing furnace 12, and calcination is performed at 1000 ° C. while controlling the heater 13 (step S2).

The firing furnace 12 is an electric furnace for firing a molded body of a ceramic such as a sheet or a tube. The firing furnace 12 has a heater 1 for heating and heating the compact.
3 is provided. Various heating elements can be used for the heater 13 depending on the temperature and atmosphere. However, the firing of the ceramic body is performed at high temperature (1000
Since it is carried out in an oxidizing atmosphere of (° C. or higher), a corresponding heating element is used. For example, there are Fe-Cr-Al alloy heating elements and Pt-Rh alloy heating elements.

The ceramic mounting portion 14 is located on the upper portion of the firing furnace 12, and one end of the ceramic molded body is mounted on the ceramic mounting portion 14.
It is a jig for fixing the position. In the case of a tubular ceramic molded body, the ceramic molded body is
It is fixed in a suspended state and fired (or calcined).

The inner diameter of the hole on the bottom surface of the ceramic mounting portion 14 is the same as the outer diameter of the cylindrical portion of the seal ring 14a. The base tube 11 is fitted into the hole and is hung on the ceramics mounting portion 14 at the holding portion of the seal ring 14a. The side of the ceramics mounting portion 14 opposite to the bottom surface is joined to the firing furnace 12 so that there is no gas leak and the weight of the base tube 11 is supported.

The seal cap 14b is a cylindrical lid, and is composed of a cylindrical portion and a cylindrical portion extending from the outer periphery of the cylindrical portion toward the base pipe 11. The inner diameter of the cylindrical portion is substantially equal to the outer diameter of the base tube 11. The lower end of the base tube 11 is closed so that the fuel gas flowing inside does not leak to the outside.
Alternatively, on the contrary, the external gas is prevented from leaking into the inside of the base pipe 11.

After step S2, the processes of steps S3 and S4 are performed. This process will be described below.

During calcination (or after calcination), the air electrode 22
An organic solvent is mixed with the raw material of 1 to form a uniform slurry 16 and the slurry 16 is poured into the container 15. After the calcination, one rubber stopper 18 is inserted into each end of the base tube 11, and the non-film-forming portion of the base tube 11 is masked with the vinyl tape 17. The base tube 11 having the vinyl tape 17 and the rubber plug 18 mounted thereon is dipped in the slurry 16 for the air electrode 22 (step S3).
The substrate tube 11 taken out from the slurry 16 is dried, thereby forming the air electrode material film (step S
4).

The same processing as in steps S3 and S4 is performed by the electrolyte membrane 21, the interconnector 23, and the fuel electrode 2.
This is sequentially performed using the slurry 16 for 0. As a result, an air electrode material film, an electrolyte film material film, an interconnector material film, and a fuel electrode material film are formed on the base tube 11.

The processing of steps S3 and S4 is an example in the case of manufacturing a vertical stripe type cylindrical SOFC. When manufacturing a horizontal striped SOFC, the fuel electrode material film, the electrolyte film material film, the interconnector material film, and the air electrode material film are formed in this order.

The container 15 is used for the slurry 16 used in the dipping method or the like. The slurry 16 is a muddy substance that is a material for each element of the fuel cell unit 19, and different materials are used for each element. Of each element, the electrolyte membrane 21 and the interconnector 2
Each material of 3 is prepared based on the conditions (a) to (c) (at least any one or two) described above. The vinyl tape 17 is a film (a fuel electrode material film, an electrolyte membrane material film, an interconnector material film, an air connector material film, and an air film) on the outer surface of the base tube 11 when the base tube 11 is dipped in the slurry 16 to form a film. This is a member for masking a portion that is not the target of the formation of the electrode material film). The rubber stopper 18 is
This is a member for preventing the slurry 16 from entering the inner portion of the base pipe 11 when the base pipe 11 is immersed in the slurry 16 to form a film, and one member is inserted into each end of the base pipe 11.

The fuel cell section 19 includes a fuel electrode 20, an electrolyte membrane 21, an air electrode 22, and an interconnector 23. Alternatively, it represents a state in the process of forming the fuel cell 10. The state is a horizontal stripe cylindrical SOF.
The case of manufacturing C will be described below as an example.

The states are (A) a state where only the fuel electrode material film is formed, (B) a state where only the fuel electrode material film and the electrolyte membrane material film are formed, and (C) the fuel electrode. A material film for electrolyte, a material film for electrolyte membrane, a material film for air electrode, (D) a material film for fuel electrode, a material film for electrolyte membrane, a material film for interconnector,
(E) One of the states in which the fuel electrode material film, the electrolyte film material film, the interconnector material film, and the air electrode material film are formed.

After step S4, the process of step S5 is performed. This processing will be described next.

The cell tube 25 produced by forming the fuel cell section 19 in the state (C) or (E) is attached to the ceramic attachment portion 14 of the firing furnace 12, and the heater 1
The fuel cell 10 is produced by sintering at 1350 ° C. while controlling 3 (step S5).

(Second Embodiment) FIG. 8 shows a flat plate type SOFC.
An example of (fuel cell 27) is shown. For the flat plate SOFC,
Similar to the cylindrical SOFC, the fuel electrode 20, the electrolyte membrane 21,
It is composed of an air electrode 22 and an interconnector 23. The material for each of the electrolyte membrane 21 and the interconnector 23 satisfies the conditions (at least any one or two) of (a) to (c) described in the first embodiment.

As described in the first embodiment, the electrolyte membrane 2 is used for manufacturing the fuel cell 10 (cylindrical SOFC).
Suppressing the shrinkage rate at the time of sintering by using, as the material of No. 1, a material obtained by adding an appropriate amount of particles having a relatively large particle size (coarse particles AA) to particles having a small particle size (fine particles BB) Is possible. In addition, this principle is based on the interconnector 2
It turns out that it holds for 3. If this principle can be applied to a flat-plate SOFC, it is considered possible to reduce the need for straightening treatment when the flat-plate SOFC is sintered. Therefore, for the fuel cell 27 as shown in FIG. 8, the electrolyte membrane 21 (or the interconnector 23) is used under the conditions (at least any one or two) of (a) to (c) described in the first embodiment. It was attempted to suppress the shrinkage rate by preparing (1). The experimental results regarding this are shown in FIG.

The results shown in FIG. 9 are obtained by using the electrolyte membrane 21 or the interconnector 23 which are each sintered alone. In FIG. 9, test number 9a, material 9b, fine particle diameter 9c, coarse particle diameter 9d, fine particle amount 9e, coarse particle amount 9f, shrinkage rate 9g, relative density 9h, average thickness 9i,
The maximum thickness 9j, the deformation amount 9k, and the deformation rate 9l are shown.

The method of calculating the relative density 9h is the same as that described in the first embodiment. The average thickness 9i and the maximum thickness 9j represent the average thickness and the maximum thickness for each of the electrolyte membrane 21 and the interconnector 23 formed by sintering. These thicknesses are different from those of the electrolyte membrane 21.
Alternatively, it is obtained by installing the interconnector 23 on the base plate and measuring the height from the base plate. The deformation amount 9k represents the difference between the maximum thickness 9j and the average thickness 9i, and the deformation rate 9l is calculated based on the average thickness 9i and the deformation amount 9k.

Test numbers 9a = 23 to 29 correspond to different materials for the electrolyte membrane 21 (however, test number 9a).
= 23 and 24 are the same.) The material of the electrolyte membrane 21 is shown in the material 9b.
When the test number 9a = 23, the fine particle amount 9e is 100%, whereas in the other cases (test number 9a = 24 to 29), the fine particle amount 9e is unified to 70%. When the test number 9a = 23, the shrinkage rate 9g is 22%, which shows that the shrinkage of the fuel cell 27 is progressing as compared with the other (test number 9a = 24 to 29). .

Deformation rate 9l when test number 9a = 23
Comparing (217%) with the test numbers 9a = 24 to 29, the shrinkage rate of 9 g is suppressed when the material corresponding to the test numbers 9a = 24 to 29 is used. In _particular, when using the _{(CeO 2) 0.8 (Gd 1} .5) 0.2, it is compared to shrinkage largely suppressed with the other,
From the viewpoint of suppressing the shrinkage rate of 9 g, it is considered that the use of this material is the most desirable.

Test numbers 9a = 30 to 33 correspond to different materials for the interconnector 23 (however, the same test numbers 9a = 30, 31, 32 are used). The material 9b has its interconnector 23
The material is shown. When test number 9a = 30,
The fine particle amount 9e is 100%, whereas in other cases (test number 9a = 31 to 33), the fine particle amount 9e is 70%.
Are unified. When the test number 8a = 30, the shrinkage rate 9g is 21%, and other (test number 9a =
31 to 33), the shrinkage of the fuel cell 27 is shown to be progressing.

Deformation rate 9l when test number 9a = 30
(310%) and test number 9a = 31 to 33
By comparison, the materials corresponding to test number 9a = 31-33
When used, the shrinkage rate of 9 g is suppressed. Special
To Ca_0.9La_0.2TiO _ThreeWhen using
Shrinkage rate of 9g is greatly suppressed compared to
From the viewpoint of suppressing 9g, it is most preferable to use this material.
Considered desirable.

From the results of FIG. 9, the materials of the electrolyte membrane 21 and the interconnector 23 were prepared based on the above conditions (a) to (c) (at least any one or two), and the prepared materials. Fuel cell 27 (flat plate SOF
C) is to be manufactured. Manufacturing method 1 of the fuel cell
The processing of 0a will be described with reference to FIG.

The raw material for the air electrode 22 is mixed with an organic solvent to form a uniform slurry 16, which is slowly poured from the knife edge onto the carrier film 28 and dried. After drying, the sheet molded body 26 is produced. Similarly, the electrolyte membrane 21, the fuel electrode 20, and the interconnector 23
The same process is performed using the above material to produce the sheet molded body 26 provided with the air electrode material film, the electrolyte film material film, the fuel electrode material film, and the interconnector material film. At this time, the electrolyte membrane 21 and the interconnector 23
The material (1) is prepared based on the above conditions (a) to (c) (at least any one or two) (step S7).

In the sheet molded body 26, the slurry 16 produced based on the respective raw materials of the fuel electrode 20, the electrolyte membrane 21, the air electrode 22 and the interconnector 23 is dried, and the dried slurry 16 is 100 mm × 100 mm. It is generated by cutting it into a square. Fuel cell 2
Reference numeral 7 is a flat plate type SOFC having elements such as a fuel electrode 20, an electrolyte 21, an air electrode 22 and an interconnector 23.
The carrier film 28 is a film for flowing out, drying, and cutting out the slurry 16 generated based on the raw materials of the fuel electrode 20, the electrolyte 21, the air electrode 22, and the interconnector 23.

Sheet molded body 2 generated in step S7
The fuel cell 27 is produced by placing 6 in the firing furnace 12 and sintering it at 1350 ° C. (step S8).

In step S7, after the sheet molded body 26 is formed on the basis of the electrolyte membrane material film or the interconnector material film, each of them may be sintered alone. In that case, in step S8, a sintered body of the electrolyte 21 or the interconnector 23 is generated.

[0074]

By using the method for producing a fuel cell according to the present invention, the shrinkage rate of the cylindrical SOFC due to sintering can be suppressed within an appropriate range, and as a result, the compactness with respect to the electrolyte and the interconnector can be secured. It is possible to produce a fuel cell that can be used.

By using the method of manufacturing a fuel cell of the present invention, the shrinkage rate of the cylindrical SOFC due to sintering can be suppressed within an appropriate range, and as a result, the fuel utilization rate can be improved. Can be generated.

By using the method for producing a fuel cell of the present invention, the shrinkage rate due to the sintering of the flat plate type SOFC can be minimized, and the need for the straightening treatment after firing can be reduced. Can be generated.

By using the method for producing a fuel cell of the present invention, it is possible to produce a fuel cell capable of improving the fuel utilization rate and the power density by minimizing the shrinkage rate due to the sintering of the flat plate type SOFC. .

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a cylindrical horizontal stripe type SOFC according to a method for manufacturing a fuel cell of the present invention.

FIG. 2 is a diagram showing a configuration of a cylindrical vertical stripe type SOFC according to the method for manufacturing a fuel cell of the present invention.

FIG. 3 is a diagram showing the results of an experiment conducted using a cylindrical horizontal stripe SOFC according to the method for producing a fuel cell of the present invention.

FIG. 4 is a diagram showing a result of an experiment conducted by using a cylindrical horizontal stripe type SOFC and various electrolyte membrane materials according to the method for producing a fuel cell of the present invention.

FIG. 5 is a diagram showing a result of an experiment conducted by using a cylindrical horizontal striped SOFC or a cylindrical vertical striped SOFC and various interconnector materials according to the method for producing a fuel cell of the present invention.

FIG. 6 is a cylindrical S according to the method for manufacturing a fuel cell of the present invention.
It is a figure which shows the process of manufacturing of OFC.

FIG. 7 is a cylindrical S according to the method for manufacturing a fuel cell of the present invention.
It is a figure which shows the process of manufacturing of OFC.

FIG. 8 is a flat plate type S according to the method for manufacturing a fuel cell of the present invention.
It is a figure which shows an example of a structure of OFC.

FIG. 9 is a flat plate type S according to the method for manufacturing a fuel cell of the present invention.
It is a figure which shows the result of the experiment performed using OFC and using various electrolyte membrane materials.

FIG. 10 is a diagram showing a process of producing a flat plate SOFC according to the method for producing a fuel cell of the present invention.

[Explanation of symbols]

11: Base tube 12: firing furnace 13: Heater 14: Ceramics mounting part 14a: seal ring 14b: Seal cap 15: Container 16: Slurry 17: Vinyl tape 18: Rubber stopper 19: Fuel cell section 20: Fuel pole 21: Electrolyte membrane 22: Air electrode 23: Interconnector 3a: test number 3b: Fine particle size 3c: coarse grain size 3d: Amount of fine particles 3e: Coarse grain amount 3f: Shrinkage rate 3 g: relative density of electrolyte membrane 3h: Power density 3i: Maximum fuel utilization rate 3l: particle size ratio 4a: test number 4b: Electrolyte membrane material 4c: Fine particle size 4d: coarse grain size 4e: Amount of fine particles 4f: Coarse grain amount 4g: Shrinkage rate 4h: Relative density of electrolyte membrane 4i: Power density 4j: Maximum fuel utilization rate 4k: Particle size ratio 5a: test number 5b: Interconnector material 5c: Fine particle size 5d: Coarse grain size 5e: Amount of fine particles 5f: Amount of coarse particles 5g: Shrinkage rate 5h: Relative density of electrolyte membrane 5i: Power density 5j: Maximum fuel utilization rate 5k: Cell configuration 5l: particle size ratio 26: Ceramic molded body 27: Fuel cell 28: Carrier film 9a: test number 9b: Material 9c: Fine particle size 9d: Coarse grain size 9e: Amount of fine particles 9f: Coarse grain amount 9g: Shrinkage rate 9h: Relative density 9i: average thickness 9j: maximum thickness 9k: Deformation amount 9l: Deformation rate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 8/12 H01M 8/12 (72) Inventor Nagao Kurume 1-1 No. 1 Watsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Industry Co., Ltd. Nagasaki Shipyard (72) Inventor Yutaka Kawaguchi 1-1, Atsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard (72) Inventor Toru Hojo 5, 717-1, Fukahori-cho, Nagasaki-shi, Nagasaki Prefecture Ryokan Engineering Co., Ltd. F term (reference) 4G031 AA01 AA04 AA08 AA12 AA16 AA19 AA23 BA03 CA08 GA03 5H026 AA06 BB01 CV02 HH05

Claims (19)

[Claims] 1. A material of the electrolyte membrane, comprising: (S1) forming a base tube; and (S3, S4, S5) forming a fuel electrode, an electrolyte membrane, and an air electrode on the base tube. Includes a first particle and a second particle, and the content ratio of the first particle is 10 to 50 vol%. 2. The fuel cell according to claim 1, wherein the ratio of the particle size (r1) of the first particles to the particle size (r2) of the second particles is 4 ≦ (r1 / r2) ≦ 30. Manufacturing method. 3. The step of forming (S3, S4, S5) according to claim 1, wherein the step of forming a fuel electrode material film, an electrolyte film material film, and an air electrode material film is performed on the substrate tube. Forming the fuel electrode, the electrolyte membrane, and the air electrode on the base tube by sintering the formed fuel electrode material film, the electrolyte membrane material film, and the air electrode material film. The relative density of the formed electrolyte membrane is 92 to 98%. 4. The contraction rate according to claim 3, wherein the contraction rate of the material film for electrolyte membrane due to sintering is 8 to 17
% Fuel cell manufacturing method. 5. The method of manufacturing a fuel cell according to claim 1, wherein the forming step (S3, S4, S5) includes a step of forming an interconnector material film on the substrate tube. 6. The step of forming (S3, S4, S5) according to claim 5, wherein the formed interconnector material film is sintered,
Forming the interconnector on the base pipe, wherein the relative density of the formed interconnector is from 92 to
98% fuel cell manufacturing method. 7. The shrinkage rate according to claim 6, wherein the shrinkage rate of the interconnector material film due to sintering is
A method for manufacturing a fuel cell, which is 8 to 17%. 8. The method of manufacturing a fuel cell according to claim 6, wherein the material of the interconnector includes third particles and fourth particles, and the content ratio of the third particles is 10 to 50 vol%. 9. The fuel cell according to claim 8, wherein the ratio of the particle diameter (r3) of the third particles to the particle diameter (r4) of the fourth particles is 4 ≦ (r3 / r4) ≦ 30. Manufacturing method. 10. A material of the electrolyte membrane, comprising: (S1) forming a base tube; and (S3, S4, S5) forming a fuel electrode, an electrolyte membrane, and an air electrode on the base tube. Includes first particles and second particles, and the ratio of the particle diameter (r1) of the first particles to the particle diameter (r2) of the second particles is 4 ≦ (r1 / r2) ≦ 30. A fuel cell manufacturing method. 11. The step of forming (S3, S4, S5) according to claim 10, wherein the step of forming a fuel electrode material film, an electrolyte membrane material film, and an air electrode material film on the base tube is performed. And a step of sintering the formed fuel electrode material film, electrolyte film material film, air electrode material film to form a fuel electrode, an electrolyte film, and an air electrode on the base tube, The relative density of the formed electrolyte membrane is 92 to 98%. 12. The shrinkage rate according to sintering of the material film for an electrolyte membrane according to claim 11,
% Fuel cell manufacturing method. 13. The method of manufacturing a fuel cell according to claim 10, wherein the step of forming (S3, S4, S5) includes the step of forming an interconnector material film on the substrate tube. 14. The step of forming (S3, S4, S5) according to claim 10, wherein the step of forming (S3, S4, S5) sinters the formed interconnector material film,
Forming interconnectors, wherein the formed interconnectors have a relative density of 92-
98% fuel cell manufacturing method. 15. The shrinkage rate according to claim 13, wherein the shrinkage rate of the interconnector material film due to sintering is
A method for manufacturing a fuel cell, which is 8 to 17%. 16. The material of the interconnector according to claim 14, wherein the material includes third particles and fourth particles, and the particle diameter (r3) of the third particles and the particle diameter (r4) of the fourth particles. And a ratio of 4 ≦ (r3 / r4) ≦ 30. 17. A fuel cell manufactured by using the method for manufacturing a fuel cell according to claim 1. Description: 18. A cylindrical horizontal stripe type solid oxide fuel cell manufactured by using the method for manufacturing a fuel cell according to claim 1. 19. A cylindrical vertical stripe type solid oxide fuel cell manufactured by the method for manufacturing a fuel cell according to claim 1. Description: