JP3466511B2 - Fuel cell manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a fuel cell, in particular, to a manufacturing method for a fuel cell having a single cell.

[0002]

2. Description of the Related Art The conventional single cell structure of a fuel cell disclosed in JP-A-63-32862, JP-A-63-32858 and JP-A-63-186074 is shown in FIG.
As shown in FIG. 2, either one or both of the air electrode 105 and the fuel electrode 106 and the electrode catalyst layer and the matrix layer 10 are
4 was integrally molded. In addition, JP-A-58-1
64153, JP-A-58-44672, and JP-A-1-176665, as shown in FIG.
A method is shown in which the air electrode 105, the fuel electrode 106, and the peripheral portion of the matrix layer 104 are film-coated or integrally molded with an end member 108 made of a fluororesin or the like.

Further, in JP-A-59-181466 and JP-A-64-41174, as shown in FIG. 8, between the air electrode 105 and the fuel electrode 106, the electrolyte-resistant fine particles and the binder are used. Matrix layer (first paste) 1
No. 04 is applied, dried, and heat-treated to form a second paste layer 109 in which electrolyte resistant fine particles are mixed with a binder and an electrolyte, and both electrodes are joined and integrated.

In the figure, reference numeral 101 is an electrode substrate, 10
Reference numeral 2 denotes an air electrode catalyst layer, and the electrode base material 01 and the air electrode catalyst layer 102 form an air electrode 105. Also,
Reference numeral 103 is a fuel electrode catalyst layer, and the electrode base material 101 and the fuel electrode catalyst layer 103 form a fuel electrode 106. 111 is an air side porous carbon plate provided with an air gas flow channel, 112 is a fuel side porous carbon plate provided with a fuel gas flow channel, and 113 is a separator.

Next, the operation of the fuel cell will be described.
The separator 113 is an impermeable and dense carbon plate, and an air-gas flow path provided on the air-side porous carbon plate 111 and the fuel-side porous carbon plate 112 arranged on both sides thereof,
The air and fuel gas supplied to the fuel gas flow path are separated. The air-side porous carbon plate 111 and the fuel-side porous carbon plate 112 supply gas to the entire surface and, at the same time, retain an electrolyte required during actual operation.

On the other hand, the electrode base material 101 is also made of porous carbon and supports the electrode catalyst layer composed of the air electrode catalyst layer 102 and the fuel electrode catalyst layer 103, and at the same time, the air side porous carbon plate 111 and the fuel. Side porous carbon plate 11
The gas supplied to the porous carbon plate composed of 2 is diffused into the electrode catalyst layer. Further, the electrolyte required for the electrode catalyst layer is supplied from the porous carbon plate.

The air and fuel gas reaching the electrode catalyst layer react through the matrix layer 104 to generate electricity. The generated electric current reacts through the matrix layer 104 to generate electric power. The generated current flows in the penetrating direction of each member by ionic conduction in the matrix layer 104 portion and electronic conduction in the other portions.

[0008]

In the conventional fuel cell, a plurality of laminated members described above are alternately and repeatedly laminated. That is, after the stacking is completed, the matrix layer 104 is sandwiched between the air electrode 105 and the fuel electrode 106, and the separator 113 not adjacent to the cooling unit is sandwiched between the air side porous carbon plate 111 and the fuel side porous carbon plate 112. Therefore, when laminating each independent member individually, there is a problem that a very large number of members must be laminated. For example, when stacking 100 cells, the matrix layer 104 and the air electrode 10 are excluded even if the cooling unit is excluded.
If the fuel electrode 106, the air-side porous carbon plate 111, the fuel electrode porous carbon plate 112, and the separator 113 were independent of each other, a total of 600 members had to be laminated.

Since each member of the conventional fuel cell is not provided with sufficient handling strength and the aim is to have a large area and a thin wall, its workability is not good. In particular,
The matrix layer 104 is preferably as thin as possible in order to reduce ionic conductive resistance during power generation, but handling is extremely difficult in the case of the matrix layer independent of the electrodes. As a countermeasure, the matrix layer 104, the air electrode 105, and the fuel electrode 106 are described in the above-mentioned conventional example in which they are integrated before stacking. Further, regarding the integration of the air-side porous carbon plate 111, the fuel-side porous carbon plate 112, and the separator 113, it is also disclosed in JP-A-60-236461.
The disclosure is made in other publications including the publication.

Here, the matrix layer 104 and the air electrode 1
05, regarding the integration of the fuel electrode 106, the problems of the conventional example will be described. The above-mentioned JP-A-63-32862, JP-A-63-32858 and JP-A-63-186074.
In the case of the publication, although the catalyst layer and the matrix layer are integrally formed and the method thereof is disclosed, there is no reference to the integral structure of the electrode seal portion. Japanese Patent Laid-Open No. 63-186074 discloses a method in which a thick catalyst layer sheet and a matrix sheet are prepared in advance, and they are simply stacked and rolled to integrate them, but in reality, the catalyst layer and the matrix layer are disclosed. However, there is a problem in that each layer cannot be made uniform no matter how much is rolled after bonding, and the layer having the weaker strength tends to be cracked or broken due to the different physical properties.

Regarding the method of applying the electrolyte, a method in which only the two catalyst layers of the air electrode or the fuel electrode and the matrix layer are integrated so that the matrix surfaces face each other and carbon paper is inserted between them is used. A method of layer integration and impregnating the carbon paper with an electrolyte is shown. However, this structure has a problem that the substantial electrolyte layer becomes two matrix layers and a carbon paper layer, which becomes very thick, and the ion conduction resistance remarkably increases, resulting in a decrease in power generation efficiency.

In the cases of JP-A-58-164153, JP-A-58-44672, and JP-A-1-176665, the fuel electrode, the air electrode, and the sealing portion around the matrix layer are made of a fluororesin film or the like. A method of integration by coating or molding is disclosed. However, when the peripheral portion of each member is coated with a film, the coated portion becomes thicker than the central portion in the surface, and there is a problem that special work is required to absorb this step. Further, in the molding of the seal portion, the problem of the seal step is eliminated, but when the temperature is high enough to melt the fluororesin, the electrode catalyst layer and the matrix layer are also subjected to a high temperature heat history, which adversely affects the electrode characteristics. There was a problem. Further, it does not mention how to impregnate the electrolyte and what the conditions should be.

Further, Japanese Patent Laid-Open No. 59-181466,
In JP-A-64-41174, a matrix layer (first paste layer) composed of electrolyte resistant fine particles and a binder is applied between electrodes, dried and heat-treated to form the electrolyte resistant fine particles, the binder and the electrolyte. There is disclosed a method of forming a second paste layer in which the two are mixed and joining and integrating both electrodes. In this case, since the matrix of the first paste layer is applied, dried and heat-treated on the surface of the catalyst layer, cracking and appearance of water repellency due to heat treatment history cannot be avoided. There is a problem that an unfired second paste layer has to be provided as a protection means and an extra matrix layer has to be formed. At the same time, since the matrix layer becomes a total of two layers and becomes thick, there is a problem that the ionic conductive resistance increases and the battery characteristics deteriorate.

Since water repellency appears in the first paste layer due to the history of heat treatment, and the electrolyte does not easily permeate sufficiently, the second paste layer is preliminarily filled with an electrolyte in the paste in order to promote sufficient electrolyte renewal in the matrix layer. It is necessary to apply a mixture of. However, in the case of a phosphoric acid fuel cell, the hygroscopicity of phosphoric acid as an electrolyte is very high,
Even after the joining and integration, moisture in the surrounding atmosphere is absorbed, which makes it difficult to handle the electrode itself, resulting in a decrease in workability. In addition, when moisture absorption by the electrolyte is remarkable, there is also a problem that the integrated electrode joined at a corner is peeled off during handling.

The present invention has been made in order to solve the above problems, and takes into consideration not only the catalyst layer (reaction part) but also the peripheral seal layer, and the thickness of the matrix layer and the electrolyte layer are increased. It is an object of the present invention to provide a method for manufacturing a fuel cell capable of joining and integrating an air electrode and a fuel electrode without doing so.

[0016]

A method of manufacturing a fuel cell according to the present invention comprises a step of filling a base material filling seal around the peripheral portions or both sides of first and second electrode base materials.
First each surface of the second electrode substrate, and simultaneously applying the second catalyst paste was coated with the first, sealing paste to the outer periphery of the second electrode substrate, Shirupe was applied
The catalyst layer is dried and the catalyst paste is baked.
The air electrode catalyst layer and the
An air electrode in which the air-side peripheral sealing layer is integrated with the same thickness,
In addition, the fuel electrode catalyst layer and the fuel side peripheral seal have the same thickness.
Step of obtaining an integrated fuel electrode, the air electrode and the fuel electrode are overlapped and pressure-bonded so that the first and second catalyst layers are in contact with the first and second surfaces of the unsintered matrix layer, respectively. At the time of pressure bonding, a step of obtaining a unit cell by pressure bonding at a temperature of 60 to 170 ° C., a surface pressure of 1.0 MPa or more and less than an electrode breaking load is included.

Further, according to the method of manufacturing a fuel cell of the present invention, the first and second electrode base materials are provided on the peripheral portion or both sides.
The step of filling the base material filling seal with the first and second electrodes.
Apply the first and second catalyst pastes to the surface of the electrode substrate.
Simultaneously with the work, the outer periphery of the first and second electrode base materials is sealed.
After applying the paste paste,
The catalyst paste is dried and calcined to remove the catalyst layer area and
And the seal area, the air electrode catalyst layer and the air side circumference, respectively.
An air electrode with the same thickness of the side sealing layer and a fuel
The electrode catalyst layer and fuel side peripheral seal are integrated with the same thickness.
The process of obtaining the burned fuel electrode, the first unbaked matrix layer
The first and second catalyst layers contact the surface and the second surface, respectively.
Stack the air electrode and fuel electrode, and crimp
The matrix layer and the air electrode and fuel electrode
Binder is applied to the surface and 0.5 MPa or less at room temperature.
In addition, by pressing with a surface pressure less than the electrode breaking load, the unit cell can be
It includes a step of obtaining.

Further, the method for producing a fuel cell according to the present invention uses a fluororesin as a binder.

The fluororesin used as the binder in the method for producing a fuel cell according to the present invention is a water-soluble or organic solvent-based polytetrafluoroethylene dispersion or tetrafluoroethylene-hexafluoropropylene copolymer dispersion. Selected from the group consisting of:
It is set to 60%.

Further, the binder used in the method for producing a fuel cell according to the present invention is cellulose which is water-soluble or dissolved in an organic solvent.

The cellulose used as the binder in the method for producing a fuel cell according to the present invention is selected from the group consisting of hydroxypropylcellulose, methylcellulose, hydroxypropylmethylcellulose and hydroxyethylmethylcellulose, and the above-mentioned cellulose solution of the binder is used. The concentration is 0.5 to 5 %.

Further, in the method for producing a fuel cell according to the present invention, the coating pattern of the binder applied to the interface between the matrix layer and the air electrode and the fuel electrode is a frame shape, and the binder is the air electrode, It is selectively applied to the interface corresponding to the seal layer forming region of the fuel electrode.

Further, in the method of manufacturing a fuel cell according to the present invention, the coating pattern of the binder applied to the interface between the matrix layer and the air electrode or the fuel electrode is streaky, and the binder is applied to the interface region. It is selectively applied.

Further, a method of manufacturing a fuel cell according to the present invention
The method is to use the peripheral part or both sides of the first and second electrode base materials.
The step of filling the base material filling seal with the first and second electrodes.
Apply the first and second catalyst pastes to the surface of the electrode substrate.
Simultaneously with the work, the outer periphery of the first and second electrode base materials is sealed.
After applying the paste paste,
The catalyst paste is dried and calcined to remove the catalyst layer area and
And the seal area, the air electrode catalyst layer and the air side circumference, respectively.
An air electrode with the same thickness of the side sealing layer and a fuel
The electrode catalyst layer and fuel side peripheral seal are integrated with the same thickness.
The process of obtaining the burned fuel electrode, the first unbaked matrix layer
The first and second catalyst layers contact the surface and the second surface, respectively.
Stack the air electrode and fuel electrode, and crimp
When doing so, wet the first and second surfaces of the matrix layer with pure water.
However, at room temperature, 2.0 MPa or more, no electrode breaking load
Crimping with full surface pressure.

In the fuel cell manufacturing method according to the present invention, the first surface and the second surface of the matrix layer are wetted with pure water in a grid pattern, and the first surface and the second surface are selectively wetted. It is a thing.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. First Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view showing a single cell structure according to the present invention. Reference numeral 1 is an electrode base material (first and second electrode base materials), 2 is an air electrode catalyst layer (first catalyst layer),
3 is a fuel electrode catalyst layer (second catalyst layer), 4 is a matrix layer, and an air electrode 5 including an electrode base material 1 and an air electrode catalyst layer 2.
Between the electrode base material 1 and the fuel electrode 6 including the fuel electrode catalyst layer 3 so that both surfaces of the matrix layer 4 are in contact with the catalyst layer to form a single cell 7. further,
An air-side base material filling seal layer 21 is arranged on the outer peripheral portion or both sides of the electrode base material 1 forming the air electrode 5, and an air-side peripheral seal layer 22 is arranged on the outer peripheral portion of the air electrode catalyst layer 2. Has been done. Similarly, a fuel-side base material filling seal layer 23 and a fuel-side peripheral seal layer 24 are also formed on the fuel electrode 6 side.

Further, in FIG. 1, reference numeral 14 denotes a composite separator in which the air-side porous carbon plate 11 and the fuel-side porous carbon plate 12 are arranged on both surfaces of the separator 13 and joined and integrated. The air side porous carbon plate 11 of the composite separator 14 is arranged so as to contact the electrode base material 1 on the air electrode 5 side of the single cell 7, and the fuel side of another composite separator 14 on the electrode base material 1 on the fuel electrode 6 side. It is possible to obtain a structure in which the porous carbon plates 12 are arranged in contact with each other and a plurality of unit cells 7 are stacked.

Next, a method for manufacturing a single cell of a fuel cell according to the present invention will be described. First, the particle size is 10 to 80n
m carbon black, thickener and pure water are mixed, stirred and pulverized, and then 60 wt% PTFE dispersion and a surfactant are added as a binder and mixed and dispersed to prepare a seal paste. The seal paste is roll-filled in the peripheral portion or both sides of the electrode base material 1 and dried. The electrode base material 1 has the same size as the planar outer shape of the final battery stack.

Next, a catalyst powder carrying platinum, a thickener and pure water are mixed, stirred and pulverized, and then a 60 wt% PEFE dispersion and a surfactant are added and mixed and dispersed to carry out a catalyst paste for a fuel electrode. To produce. In this case, P
The TFE dispersion not only functions as a binder, but also has a function of suppressing excessive wetting by the electrolyte during electrode reaction. In the case of the air electrode 5, what is supported on the catalyst powder is different, but the catalyst paste manufacturing process is the same.

Next, seal filling is performed so as to surround the outer periphery of the electrode base material 1 constituting the air electrode 5 and the fuel electrode 6, and the air side base material filling seal layer 21 and the fuel side base material filling seal layer 23 are respectively formed. Form. After that, the seal paste and the catalyst paste manufactured as described above are simultaneously coated on the electrode base material 1. At this time, the catalyst paste is applied to the central portion of the electrode where the electrode reaction takes place, and the seal paste is applied to the peripheral portion surrounding the outer periphery thereof so as to have a constant thickness (thick film coating).

Thereafter, the applied seal paste and catalyst paste are dried and fired, and the air electrode catalyst layer 2 and the air-side peripheral seal layer 22 are integrated into the catalyst layer region and the seal region with the same thickness, respectively. It is possible to obtain the fuel electrode 6 in which the air electrode 5, the fuel electrode catalyst layer 3 and the fuel side peripheral seal layer 23 are integrated in the same thickness. In addition,
Compared to the catalyst paste, the seal paste has a PT
Since the FE content is extremely low, the sealing area shows almost no water repellency as compared with the catalyst layer area although it has undergone a firing history, and sufficient electrolyte is permeated and impregnated into the sealing area to form a wet seal. Form.

Further, silicon carbide having an average particle size of 0.5 to 5 μm, pure water, and 60 wt% PTF as a binder.
E dispersion and a surfactant are added and mixed and dispersed, and then dried without heating. A plasticizer is added to this, and the mixture is kneaded, rolled, degreased and dried to form a matrix sheet having a predetermined thickness. The matrix sheet forming the matrix layer 4 is
It is an unfired product that has not been heat-treated, has no water repellency, and is molded to have a dimension that is slightly larger in the vertical and horizontal dimensions than the planar external dimensions of the final battery stack.

Finally, as shown in FIG. 2, the matrix sheet obtained as described above is placed on the upper surface of the fuel electrode 6 on the catalyst layer side, and the catalyst layer side of the air electrode 5 is in contact with the matrix sheet. Electric heater 3
A pressure device 31 having a built-in No. 3 heat-bonds them under the conditions of a temperature of 60 to 170 ° C. and a surface pressure of 1.0 MPa or more (however, less than the electrode breaking load). It is P to heat above 60 ℃
This is to make the TFE dispersion easier to fit by thermal deformation, but conversely, if the temperature is set to 170 ° C. or higher, it becomes too familiar and the influence on the electrode pore structure becomes large. As a result of making trials with various surface pressures, the air electrode 5, the matrix layer 4,
It was found that the pressure contact pressure of 1.0 MPa or more is required to stabilize the joining of the three layers of the fuel electrode. Further, since the matrix layer 4 is not heat-treated at a high temperature such that the component fluororesin is melted, the matrix layer 4 is not yet provided with water repellency and is easily impregnated with the electrolyte.

When heating and joining the three layers as described above, a holding jig 32 for holding the three layers is used. The holding jig 32 holds the fuel electrode 6 and the air electrode during the stacking work. 5
The device is designed so that it can be accurately and easily aligned. The outer dimensions of the matrix layer 4 are set so as to have a plane shape slightly larger than that of the fuel electrode 6 and the air electrode 5. However, the matrix layer 4 protrudes so as to match the sizes of the air electrode 5 and the fuel electrode 6 after heating and bonding. Since the outer side surface of the single cell can be smoothed by cutting the open portion, no special work is required for the peripheral sealing portion of the single cell 7 in which the three layers are integrated.

In the single cell 7 obtained by the above method, the three layers are bonded and integrated in advance with an excessive surface pressure, so that the contact resistance is higher than that in the conventional case where the three layers are independent. Decrease. Also, since each layer is originally manufactured with a uniform thickness over the entire surface, and there are no seal members with different thicknesses in the plane,
It is possible to make the thickness of the single cell integrally bonded with three layers uniform over the entire surface with high accuracy.

In order to confirm this, in the conventional structure in which the unit cells 7 produced by the manufacturing method shown in the first embodiment are stacked for 10 cells, and the sealing portion is a separate member and three layers are independent. In the case of stacking 10 cells, the same load was applied to both cells and the in-plane surface pressure distribution was measured and compared. As a result, the surface pressure ratio between the in-plane central portion of the cell and the peripheral seal portion was 1: 3 to 4 in the conventional configuration cell, but was 1: 1 to 1.3 in the single cell of the first embodiment of the present invention. The difference from 5 was significantly smaller.

That is, in the conventional structure cell, the thickness of the peripheral portion is increased so that the peripheral seal portion is always in contact with the seal portion so that the sealing performance is not deteriorated. Therefore, almost no surface pressure is applied to the in-plane central portion. It was in a state of not having. However, it has been found that in the single cell according to the present invention, since the thickness of the entire flat surface is uniform, it is possible to secure a necessary sealing partial surface pressure and at the same time, to provide a sufficient surface pressure to the central portion of the electrode.

As described above, according to the fuel cell including the unit cell 7 of the first embodiment of the present invention, a uniform thickness can be obtained over the entire surface of the cell, so that the sealing performance between the laminated cells is deteriorated. It is possible to improve the substantial surface pressure of the electrode reaction portion without any need, and to significantly reduce the contact resistance loss during power generation. Ie. It is possible to improve the cell characteristics, and it is possible to reduce the number of stacked cells by the amount of the improved characteristics.

Embodiment 2. Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 3, reference numeral 25 is a binder applied to the entire joint surface between the air electrode 5 and the matrix layer 4 constituting the single cell, the joint surface between the fuel electrode 6 and the matrix layer 4, and 31a is a pressurizing device. In addition, the same reference numerals as those already used for the description indicate the same or corresponding portions. In the above-described first embodiment, an example in which the air electrode 5, the matrix layer 4, and the fuel electrode 6 are pressure-bonded to each other while heating and bonding without interposing a binder between the layers has been described. In the second embodiment, the binder 2 is provided between the layers.
An example in which No. 5 is arranged and pressure bonding is performed at room temperature is shown.

The production of the matrix sheet to be the air electrode 5, the fuel electrode 6 and the matrix layer 4 is carried out in the same manner as in the first embodiment, and in the subsequent three-layer bonding, as shown in FIG. The fuel electrode 6 is arranged on the nipping tool 32 arranged on the pressurizing surface side of the pressurizing device 31a, which is not provided with the catalyst layer side up, and the binder 25 is formed on the entire upper surface of the fuel electrode 6. And a matrix sheet to be the matrix layer 4 is overlaid. Further, the binder 2 is applied on the upper surface of the matrix sheet.
5 is applied, and the air electrode 6 is superposed on the matrix sheet so that the catalyst layer side faces each other. The three layers are fixed by the sandwiching jig 32, and pressure bonding is performed by the pressure device 31a at a surface pressure of 0.5 MPa or more (but less than the electrode breaking load) to perform pressure bonding and integration at room temperature to obtain a single cell.

As the binder 25, the above-mentioned electrode catalyst layer,
The water-based PTFE dispersion of fluororesin used for the base material filling seal, the peripheral seal and the formation of the matrix layer 4 was used. In the manufacturing method shown in the second embodiment, as the binder 25, the particle solid content of the PTFE dispersion is 5 to 60%, that is, the PTFE dispersion stock solution or pure water diluted and adjusted can be used. From the viewpoint of bonding strength, the particle solid content is 10
It is preferably in the range of 30%.

In the unit cell manufactured by the above manufacturing method, the air electrode 5, the matrix layer 4, and the fuel electrode 6 are firmly joined, and peeling does not occur, and handling is easy. In addition, since the three-layer bonding can be integrated with a low surface pressure without heating during the three-layer bonding, workability of the bonding work is improved, and energy for heating can be saved.

Although it has been shown that a PTFE dispersion is used as the bonding agent 25, an organic solvent-based PTF is used.
The same effect can be obtained with E dispersion or FEP dispersion of organic solvent type. It goes without saying that it is possible to use the pressurizing device 31 provided with the electric heater 33 shown in the first embodiment and to use it with the electric heater 33 turned off.

Embodiment 3. Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 4, reference numeral 25a indicates a binder applied to the region corresponding to the outer periphery of the single cell when the three layers are bonded. In addition, the same reference numerals as those already used for the description are the same, Or, it shows a considerable portion. In the second embodiment described above, the method of using the PTFE dispersion or FEP dispersion of the fluororesin as the binder 25 for joining the three layers constituting the single cell has been described. A case where cellulose having a small effect on the stacking operation and strong adhesiveness at a low solution concentration is used as the adhesive 25a will be described.

As the binder 25a, it is possible to use a cellulose powder dissolved and adjusted to a solution concentration of 0.5 to 5% with pure water, but it is 0 from the viewpoint of coating workability related to bonding strength and viscosity. It is desirable to be in the range of 0.5 to 5%.
Here, as shown in FIG. 4, the fuel electrode 6 was prepared by dissolving and adjusting hydroxypropylmethylcellulose powder with pure water.
After being applied in a frame shape on the fuel-side base material filling seal layer 23 around the catalyst layer and around the upper surface of the matrix layer 4,
A matrix sheet to be the matrix layer 4 is sandwiched between the air electrode 5 and the fuel electrode 6, and they are superposed, and pressure bonding is performed by a pressure device 31a at room temperature at a surface pressure of 0.5 MPa and a uniform thickness in the plane. An integrated single cell can be obtained.

The single cell produced by the process as described above, the air electrode 5, the matrix layer 4, the fuel electrode 6 without the Turkey occurred peeling are strongly bonded, the handling is easy. There is also an effect that heating is not necessary. Furthermore, the three layers can be integrated by selectively applying the binder 25a not to the entire bonding surface but to the region corresponding to the outer peripheral portion, and the workability of applying the binder is improved. At the same time, there is an effect that the amount of the adhesive 25a used can be reduced.

Although an example of using water-soluble hydroxypropylmethylcellulose powder as the binder 25a has been shown, the same applies when water-soluble or organic solvent-soluble hydroxypropylcellulose, methylcellulose, hydroxyethylmethylcellulose or the like is used. The effect can be obtained.

In the above example, when the binder 25a is applied to the periphery of the fuel electrode catalyst layer 3 on the region corresponding to the fuel side base material filling seal layer 23 and to the periphery of the matrix layer 4 in a frame shape. About the air electrode 5 and the fuel electrode 6
It is also possible to apply it in a streak shape on a part of the catalyst layer and the seal part.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 5, reference numeral 26 is pure water which plays a role of a binder for wetting both surfaces of the matrix layer 4 at the time of joining three layers, and the same reference numerals as those already used for the description are the same, Or, it shows a considerable portion. In the above-described Embodiments 2 and 3, an example in which the binders 25 and 25a are applied to the interfaces for joining the three layers constituting the single cell has been shown. However, in Embodiment 4, the matrix layers 4 and A method of wetting both surfaces of the matrix sheet to be joined with pure water 26 will be described.

The air electrode 5, the matrix layer 4, and the fuel electrode 6 are similarly formed by the method shown in the first embodiment. At the final joining of the three layers, as shown in FIG. 5, both surfaces of the matrix layer 4 are wetted with pure water 26, and the air electrode 5 and the fuel electrode 6 are formed.
Are superposed on each other, and are pressure-bonded and integrated with a pressure device 31a at room temperature at a surface pressure of 2.0 MPa or more (however, less than the electrode breaking load) to obtain a single cell. In this method, since three layers can be joined and integrated without heating, workability of the joining work is good, heating energy can be saved, and pure water only needs to be prepared.

In the method of manufacturing a single cell according to the fourth embodiment, pure water 26 in which a part of the unsintered PTFE dispersion in the matrix layer 4 wets the surface of the matrix layer 4
It penetrates inside and plays the role of a binder. However, unlike the second embodiment, since the binder 25 or the like is not specially applied, the joining cannot be performed under the surface pressure of 2.0 MPa or less, and the surface pressure of 2.0 M is required to integrate the three layers.
Pa or more is required.

In addition to the method of wetting the entire surface of the matrix layer 4 with the pure water 26, for example, the first surface of the matrix layer 4 which is in contact with the fuel electrode 6 is a region in which the pure water 26 is wet in a vertical stripe shape. On the other hand, the matrix layer 4 is formed on the second surface of the matrix layer 4 which is in contact with the air electrode 5 in a laterally streaky manner by being wetted by the pure water 26.
As a whole, it is possible to obtain a state where it is wet with pure water 26 in a grid pattern. Pure water 26 on both surfaces of the matrix layer 4
It is also possible to obtain a sufficient joining force by wetting in a grid shape without needing to wet it with.

The single cell formed by the manufacturing method shown in the fourth embodiment can be integrated into three layers without heating, the workability of the joining work is good, and the heating energy can be saved. Since it is only necessary to prepare the pure water 26 without using a special binder, the fuel cell can be manufactured at low cost.

[0054]

The method of manufacturing a fuel cell according to the present invention comprises:
A step of filling the peripheral portion or both sides of the first and second electrode base materials with a base material filling seal, and applying the first and second catalyst pastes to the surfaces of the first and second electrode base materials, respectively. At the same time, after applying the seal paste on the outer periphery of the first and second electrode base materials, the applied seal paste and the catalyst paste are applied.
The paste is dried and calcined to remove the catalyst layer area and the sea.
Air cathode catalyst layer and air side peripheral seal, respectively.
Of the air electrode and fuel electrode, in which
The step of obtaining a fuel electrode in which the medium layer and the fuel-side peripheral seal are integrated with the same thickness, and the first and second catalyst layers are formed on the first and second surfaces of the unbaked matrix layer, respectively. The air electrode and the fuel electrode are overlapped so that they contact each other and crimped.
Since it includes a step of obtaining a single cell by pressure bonding at a temperature of 0 to 170 ° C., a surface pressure of 1.0 MPa or more and less than an electrode breaking load, a catalyst layer containing a seal paste forming an air electrode and a fuel electrode is formed. It is possible to form a uniform thickness,
It is possible to improve the characteristics of the obtained cell, and it is possible to obtain a single cell that does not peel off without using a binder for pressure bonding the matrix layer to the air electrode and the fuel electrode.

Further, in the method for producing a fuel cell according to the present invention , the step of filling a base material filling seal around the peripheral portions or both sides of the first and second electrode base materials, the first and second electrode base materials described above. At the same time as applying the first and second catalyst pastes to the surfaces of the above, and at the same time applying the seal paste to the outer periphery of the first and second electrode base materials, respectively, the applied seal paste and the catalyst paste are dried. , Calcination is performed, and an air electrode in which the air electrode catalyst layer and the air-side peripheral seal layer are integrated with the same thickness in the catalyst layer region and the seal region, and the fuel electrode catalyst layer and the fuel-side peripheral seal are integrated with the same thickness The step of obtaining a modified fuel electrode, the first surface of the unsintered matrix layer, the first electrode, the second electrode respectively on the second surface, the air electrode, the fuel electrode is superposed and pressure-bonded, When crimping, the above matri Since a binder is applied to the interface between the electrode layer and the air electrode and the fuel electrode, and a pressure is applied at room temperature to a pressure of 0.5 MPa or more and less than the electrode breaking load, a unit cell is obtained. It is possible to form a catalyst layer containing a seal paste that constitutes the air electrode and the fuel electrode to a uniform thickness, and it is possible to improve the characteristics of the resulting cell, and to prevent a single cell that does not peel off. It is possible to obtain.

Further, according to the method for producing a fuel cell of the present invention, a fluorocarbon resin or cellulose is used as a binder for pressure-bonding the matrix layer to the air electrode and the fuel electrode to obtain a single cell without peeling. Is possible.

Further, according to the method for producing a fuel cell of the present invention, when cellulose is used as a binder to press-bond the matrix layer to the air electrode and the fuel electrode, the application pattern of the binder is frame-shaped or striped. Sufficient bonding can be achieved even if the interface is selectively applied, such as in the form of a sheet, and the amount of the binder used can be reduced.

Further, a method of manufacturing a fuel cell according to the present invention
The method is to use the peripheral part or both sides of the first and second electrode base materials.
The step of filling the base material filling seal with the first and second electrodes.
Apply the first and second catalyst pastes to the surface of the electrode substrate.
Simultaneously with the work, the outer periphery of the first and second electrode base materials is sealed.
After applying the paste paste,
The catalyst paste is dried and calcined to remove the catalyst layer area and
And the seal area, the air electrode catalyst layer and the air side circumference, respectively.
An air electrode with the same thickness of the side sealing layer and a fuel
The electrode catalyst layer and fuel side peripheral seal are integrated with the same thickness.
The process of obtaining the burned fuel electrode, the first unbaked matrix layer
The first and second catalyst layers contact the surface and the second surface, respectively.
Stack the air electrode and fuel electrode, and crimp
When doing so, wet the first and second surfaces of the matrix layer with pure water.
However, at room temperature, 2.0 MPa or more, no electrode breaking load
A single cell that does not come off is obtained by crimping with full surface pressure
It is possible.

Further, according to the method of manufacturing a fuel cell of the present invention, the first surface and the second surface of the matrix layer are wetted with pure water in a grid pattern so that the entire surface of the matrix layer and the air can be removed even if the entire surface is not wetted. Crimping with the electrode and fuel electrode is possible.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of a single cell constituting a fuel cell according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of the unit cell according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing the manufacturing process of the unit cell according to the second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the manufacturing process of the unit cell according to the third embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the manufacturing process of the unit cell according to the fourth embodiment of the present invention.

FIG. 6 is a view showing a cross section of a single cell constituting a fuel cell according to a conventional technique.

FIG. 7 is a view showing a cross section of a single cell constituting a fuel cell according to another conventional technique.

FIG. 8 is a cross-sectional view showing a process of manufacturing a single cell according to a conventional technique.

[Explanation of symbols]

1. Electrode substrate 2. Air electrode catalyst layer 3. Fuel electrode catalyst layer 4. Matrix layer 5. Air electrode 6. Fuel electrode 7. Single cell 11. Air side porous carbon plate 12. Fuel side porous carbon plate 13. Separator 14. Composite separator 21. Air-side base material filling seal layer 22. Air side peripheral sealing layer 23. Fuel side base material filling seal layer 24. Fuel side peripheral sealing layers 25, 25a. Binder 26.
Pure water 31, 31a. Pressure device 32. Holding jig 33. Electric heater.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 8/02

Claims (10)

(57) [Claims] 1. A step of filling a peripheral portion or both sides of a first and a second electrode base material with a base material filling seal, wherein the surface of the first and second electrode base materials is a first and a second, respectively. At the same time as applying the catalyst paste, the seal paste is applied to the outer peripheries of the first and second electrode base materials, and then the applied seal paper is applied.
The catalyst and catalyst paste are dried and fired to form the catalyst layer area.
The air electrode catalyst layer and the
An air electrode with a uniform air-side peripheral sealing layer with the same thickness,
And the fuel electrode catalyst layer and the fuel side peripheral seal have the same thickness.
Obtaining a conjugated fuel electrode, the first surface of the unfired matrix layer, respectively the first to the second surface, the air electrode, by superposing the fuel electrode and pressed so that the second catalyst layer in contact with ,
At the time of pressure bonding, a temperature of 60 to 170 ° C., 1.0 MPa or more,
A method for producing a fuel cell, comprising the step of obtaining a single cell by pressure bonding under a surface pressure less than an electrode breaking load. 2. A peripheral portion or both of the first and second electrode base materials.
Step of filling the side with the base material filling seal, the above first, second
The surface of the second electrode base material has a first and second catalyst pace, respectively.
At the same time as coating the outer surface of the first and second electrode base materials.
After applying the seal paste on the circumference,
The catalyst and catalyst paste are dried and fired to form the catalyst layer area.
The air electrode catalyst layer and the
An air electrode with a uniform air-side peripheral sealing layer with the same thickness,
And the fuel electrode catalyst layer and the fuel side peripheral seal have the same thickness.
Step of obtaining a solidified fuel electrode, unbaked matrix layer
The first and second catalyst layers are in contact with the first and second surfaces, respectively.
So that the air electrode and the fuel electrode are overlapped and crimped,
At the time of pressure bonding, the matrix layer and the air electrode and the fuel electrode
A binder is applied to the interface of and the pressure is 0.5 MPa at room temperature.
As described above, by pressing with a surface pressure less than the electrode breaking load, the unit cell
For producing a fuel cell, including the steps of obtaining
Law. 3. The method for producing a fuel cell according to claim 2 , wherein the binder is a fluororesin. 4. The fluororesin is selected from the group consisting of water-soluble or organic solvent-based polytetrafluoroethylene dispersions and tetrafluoroethylene-hexafluoropropylene copolymer dispersions, and has a particle solid content of 5 It is -60%, The manufacturing method of the fuel cell of Claim 3 characterized by the above-mentioned. 5. The method for producing a fuel cell according to claim 2 , wherein the binder is water-soluble or cellulose dissolved in an organic solvent. 6. The fuel according to claim 5 , wherein the cellulose is selected from the group consisting of hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose and has a solution concentration of 0.5 to 5 %. Battery manufacturing method. 7. The coating pattern of the binder applied to the interface between the matrix layer and the air electrode and the fuel electrode has a frame shape, and the binder corresponds to the seal layer forming region of the air electrode and the fuel electrode. claim characterized in that it is selectively applied to the interface 5
A method for manufacturing the fuel cell described. 8. The coating pattern of the binder applied to the interface between the matrix layer and the air electrode or the fuel electrode is streaky, and the binder is selectively applied to the interface region. The method of manufacturing a fuel cell according to claim 5 . 9. A peripheral portion or both of the first and second electrode base materials.
Step of filling the side with the base material filling seal, the above first, second
The surface of the second electrode base material has a first and second catalyst pace, respectively.
At the same time as coating the outer surface of the first and second electrode base materials.
After applying the seal paste on the circumference,
The catalyst and catalyst paste are dried and fired to form the catalyst layer area.
The air electrode catalyst layer and the
An air electrode with a uniform air-side peripheral sealing layer with the same thickness,
And the fuel electrode catalyst layer and the fuel side peripheral seal have the same thickness.
Step of obtaining a solidified fuel electrode, unbaked matrix layer
The first and second catalyst layers are in contact with the first and second surfaces, respectively.
So that the air electrode and the fuel electrode are overlapped and crimped,
A method for manufacturing a fuel cell, wherein the first surface and the second surface of the matrix layer are wetted with pure water at the time of pressure bonding, and pressure-bonded at a surface pressure of 2.0 MPa or more and less than an electrode breaking load at room temperature. 10. A first side of the matrix layer, the pattern of the second surface wetting with pure water is the lattice shape, the first surface, according to claim 9, wherein the selectively wets it the second surface Fuel cell manufacturing method.