WO2006082986A1

WO2006082986A1 - Fuel cell and method of producing fuel cell

Info

Publication number: WO2006082986A1
Application number: PCT/JP2006/302097
Authority: WO
Inventors: Yuichiro Hama
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2005-02-01
Filing date: 2006-02-01
Publication date: 2006-08-10
Also published as: JP2006216281A

Abstract

A tubular fuel cell having a tubular joint body, a reception section for receiving the tubular joint body, and a collector formed by filling the inside and outside of the tubular joint body with electrically conductive beads. The tubular joint body is composed of a tubular electrolyte film, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte film, and an air electrode provided on the other of the inner and outer surfaces.

Description

Description Fuel cell and fuel cell manufacturing method [Technical Field]

The present invention relates to a fuel cell, in particular, a cylindrical fuel cell and a method for manufacturing the same. [Background]

As one of the countermeasures against environmental problems and resource problems, electrochemical reaction using oxidizing gas such as oxygen and air and reducing gas such as hydrogen and methane (fuel gas) or liquid fuel such as methanol as raw materials Fuel cells that generate chemical power by converting chemical energy into electrical energy are attracting attention. A fuel cell has a fuel electrode (an anode catalyst layer) on one side of the electrolyte membrane and an air electrode (forced sword catalyst layer) on the other side of the electrolyte membrane with the electrolyte membrane in between. A diffusion layer is further provided on the outside of each catalyst layer that sandwiches the catalyst, and these are sandwiched by separators provided with passages for supplying raw materials. A battery is configured by supplying raw materials such as hydrogen and oxygen to each catalyst layer to generate electricity. .

During power generation of the fuel cell, if the raw material supplied to the fuel electrode is hydrogen gas and the raw material supplied to the air electrode is air, hydrogen ions and electrons are generated from the hydrogen gas at the fuel electrode. The electrons reach the air electrode from the external terminal through the external circuit. At the air electrode, water is generated by oxygen in the supplied air, hydrogen ions that have passed through the electrolyte membrane, and electrons that have reached the air electrode through an external circuit. In this way, a chemical reaction occurs at the fuel electrode and the air electrode, generating electric charge and functioning as a battery. This fuel cell has a variety of sources of clean energy due to the abundance of raw material gas and liquid fuel used for power generation and the fact that the substance discharged from the power generation principle is water. Considered.

As such a fuel cell, a tubular (cylindrical) fuel cell is known. A tubular fuel cell has a feature that it can be easily downsized as compared with a planar fuel cell. For example, in Japanese Patent Application Laid-Open No. 2 093-2 9 7 3 7 2, a fuel electrode is provided on one of the inner and outer surfaces of a tubular polymer electrolyte membrane, and an air electrode is provided on the other surface. A tube-shaped fuel cell is described in which a carbon fiber carrying a catalyst is disposed on one or both of a fuel electrode and an air electrode.

JP-A-11-1 1 1 3 1 3 discloses that a tube-shaped polymer electrolyte membrane is provided with a fuel electrode on one of the inner and outer surfaces and an air electrode on the other surface. The first layer of conductive felt with fuel reforming function is lined, and a coiled elastic support material is inserted inside the first layer to press the first layer in close contact with the inner peripheral surface of the tube by expansion force. A tubular fuel cell is formed by lining a second layer of a conductive film having a fuel reforming function inside a coiled elastic support material and inserting a fuel supply conductive tube inside the second layer. Is described. In Patent Document 2, by using a conductive felt and a coiled elastic support material as a diffusion layer that plays the role of a current collector, the diffusion layer is packed inside in close contact with the electrode without damaging the electrode. It can be done.

On the other hand, in Japanese Patent Application Laid-Open Nos. 2000-0 6 8 1 12 and 2 0 4-7 7 1 4 5 6, spherical titanium powder is used as a current collector in a polymer electrolyte fuel cell. It describes the use of a porous conductive plate that has been sintered and has a smooth surface. As a result, damage to adjacent electrodes can be suppressed.

[Disclosure of the Invention]

However, in the tubular fuel cell described in Japanese Patent Laid-Open No. 20-2973 72, it is necessary to insert carbon fiber into the tube as a current collector. Will damage the electrode. In addition, as shown in FIG. 6, the carbon fiber 30 pierces the electrolyte membrane 32 and the catalyst layer 34 due to the shape of the carbon fiber, causing cross-leakage during power generation, which makes it impossible to generate power.

In addition, in the tubular fuel cell described in JP-A-11-1 1 1 3 1 3, a conductive felt as a current collector is used even though a coil-shaped elastic support material is used. It is necessary to pack it softly with a force that does not damage the electrode, which may damage the electrode. In addition, after packing the first layer of conductive felt, it is necessary to insert a coil-like elastic support material and pack the second layer of conductive felt, which complicates the process. Furthermore, the porous conductive plate described in Japanese Patent Application Laid-Open Nos. 2000-0 6 8 1 1 2 and 2 0 4-7 7 1 4 5 6 lacks flexibility and has a tubular shape. It is difficult to use it as a current collector by inserting it into the fuel cell.

The present invention relates to a cylindrical electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and a void provided on the other surface of the inner and outer surfaces of the electrolyte membrane so as to face the fuel electrode. In a cylindrical fuel cell having a cylindrical joined body having an air electrode, a cylindrical fuel cell capable of easily forming a current collector while suppressing damage to electrodes inside the cylinder, and a method for manufacturing the same It is.

The present invention is a tubular fuel cell, comprising a tubular electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and the other surface of the inner and outer surfaces of the electrolyte membrane. An air electrode provided; a cylindrical joined body having: a housing portion for housing the tubular joined body; and inner and outer sides of the tubular joined body filled with conductive beads. A current collector;

In the fuel cell, it is preferable that the conductive beads have an average particle diameter that changes stepwise along the long axis direction of the cylindrical joined body.

The present invention is also a method for manufacturing a cylindrical fuel cell, comprising a cylindrical electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and inner and outer surfaces of the electrolyte membrane. A current collector is formed by filling inner and outer sides of a joined body having an air electrode provided on the other surface of the air electrode so as to face the fuel electrode, and a conductive bead.

In the method for manufacturing a fuel cell, it is preferable that the conductive beads are filled with vibration.

In the fuel cell manufacturing method, it is preferable to press the conductive beads after filling the conductive beads.

In the fuel cell manufacturing method, it is preferable that the conductive beads are filled so that the average particle diameter changes stepwise along the long axis direction of the cylindrical assembly.

The present invention relates to a cylindrical electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and a void provided on the other surface of the inner and outer surfaces of the electrolyte membrane so as to face the fuel electrode. In a cylindrical fuel cell having a cylindrical joined body having an air electrode, a tubular joined body A fuel cell and a method of manufacturing the fuel cell can be formed by filling conductive beads on the inside and outside of the tube to suppress damage to the electrodes inside the cylinder and easily forming a current collector.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the configuration of a fuel cell according to an embodiment of the present invention. FIG. 2 is a diagram showing an axial cross section of an example of a fuel cell according to an embodiment of the present invention.

FIG. 3 is a diagram showing a method for manufacturing a fuel cell according to an embodiment of the present invention.

FIG. 4 is a diagram showing an axial cross section of another example of the fuel cell according to the embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the current density and voltage of the fuel cells in Example 1 and Comparative Example 1 of the present invention.

FIG. 6 is a view showing a cross section in the axial direction of a conventional tubular fuel cell using carbon fiber as a current collector.

[Best Mode for Carrying Out the Invention]

Hereinafter, a fuel cell according to an embodiment of the present invention will be described.

A fuel cell according to an embodiment of the present invention includes a cylindrical electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and air provided on the other surface of the inner and outer surfaces of the electrolyte membrane. A cylindrical joined body having a pole, a storage portion for housing the tubular joined body, and a current collector formed by filling the inside and outside of the tubular joined body with conductive beads. Yes.

An outline of an example of a fuel cell 1 according to an embodiment of the present invention is shown in FIG. 1, and the configuration will be described. The fuel cell 1 includes an electrolyte membrane 10, a fuel electrode (anode catalyst layer) 12, an air electrode (cathode catalyst layer) 14, current collectors 16 a and 16 b, and a storage unit 18. The

In the fuel cell 1, a fuel electrode 1 2 is provided on the inner surface of a cylindrical electrolyte membrane 10, an air electrode 14 is provided on the outer surface of the electrolyte membrane 10, and a cylindrical assembly (MEA: M em brane E lectrode As s emb ly) 20 has been established. The cylindrical joined body 20 is housed in the housing portion 18, and the current collectors 16 a and 16 b are formed by filling the inside and outside spaces of the joined body 20 with conductive beads. In the joined body 20, the fuel electrode 12 may be provided on the outer surface of the cylindrical electrolyte membrane 10, and the air electrode 14 may be provided on the inner surface of the electrolyte membrane 10. Normally, the outer surface of the cylindrical electrolyte membrane 10 may be provided. The air electrode 14 is provided on the inner surface of the electrolyte membrane 10, and the fuel electrode 12 is provided on the inner surface of the electrolyte membrane 10.

In such a fuel cell 1, the current collector 16a formed inside the joined body 20 and the current collector 16b formed outside the joined body 20 are electrically connected to an external circuit, If a raw material is supplied to the inside and outside of the joined body 20 and operated, it can function as a battery.

The electrolyte membrane 10 is not particularly limited as long as it is a material having high ion conductivity such as proton (H +) or oxygen ion (O ² —). Examples thereof include a solid polymer electrolyte membrane and a stabilized zirconia membrane. However, a solid polymer electrolyte membrane such as perfluorosulfonic acid is preferably used. Specifically, Goreselect (registered trademark) of Japan Gore-Tex Co., Ltd., Nafion (registered trademark) of Du Pont (Du Pont), and Aciplex (A) of Asahi Kasei Co., Ltd. (A) Perfluorosulfonic acid solid polymer electrolyte membranes such as cip 1 e X (registered trademark) and Flemion (registered trademark) of Asahi Glass Co., Ltd. can be used. The thickness of the electrolyte membrane 10 is, for example, 10 m to 200 m, preferably 30 ^ m to 50 m.

The fuel electrode 12 includes, for example, a catalyst such as carbon carrying platinum (Pt) or the like together with another metal such as ruthenium (R _U ) dispersed in a resin such as a solid polymer electrolyte such as naphthion (registered trademark). The film was formed. The film thickness of the fuel electrode 12 is, for example, 1π! ~ 100 μm, preferably 1 μπ! The range is ~ 2◦ m.

The air electrode 14 is formed, for example, by dispersing a catalyst such as carbon carrying platinum (Pt) or the like in a resin such as a solid polymer electrolyte such as naphthion (registered trademark). The film thickness of the air electrode 14 is, for example, in the range of 1 μm to 100 m, preferably 1 m to 20; um. The joined body 20 including the electrolyte membrane 10, the fuel electrode 1 2, and the air electrode 1 4 may be in a cylindrical shape, for example, a cylindrical shape; a polygonal cylindrical shape such as a triangular cylinder, a square cylinder, a pentagonal cylinder, a hexagonal cylinder, or the like. It may be any shape such as an elliptical cylinder, but is usually cylindrical. Here, in this specification, “tubular” includes a solid body in addition to a hollow body.

Fig. 2 shows an enlarged view of the AA 'cross section of fuel cell 1 in Fig. 1. As shown in FIG. 2, the current collector 16 is composed of conductive 1 and raw beads 2 2. Examples of the conductive beads 22 include metal-coated particles such as carbon or titanium whose surface is coated with a metal such as gold or platinum, and metal particles such as gold or platinum.

The shape of the conductive beads 22 is not particularly limited as long as the bonded body 20 does not need to be damaged or pierced. However, in order to suppress the bonded body 20 from being damaged or pierced, the conductive beads 22 should be filled uniformly. For this purpose, a spherical shape or an elliptical shape is preferable, and a spherical shape is more preferable for close packing.

The average particle size of the conductive beads 2 2 is preferably in the range of 10 μm to 500 μm, 5 0 ί π! Les, more preferred to be in the range of ~ 2 0 0 iz m. If the particle size is smaller than 10 zm, the packing density increases, and the raw material supply efficiency may be reduced. If the particle size is larger than 50 in, the packing density is lowered, the contact area with the joined body 20 is lowered, and the current collection efficiency may be lowered.

Here, “average particle size” is the average value of 100 particle sizes measured on a microscope image. In the case of an elliptical particle, the average particle diameter of the conductive beads 22 is the long diameter of the particle on the microscope image when the particle is observed with a microscope (the maximum between any two points on the particle outline). Value).

“Spherical” is expressed by the circularity SF obtained by the following method. The degree of circularity is the value obtained by dividing the circumference L of the circle obtained from the same circle equivalent diameter as the projected area of the particle when observed with a microscope by the circumference D of the projected image of the particle (SF = L ZD) In the case of a true sphere, SF = 1, and in the case of an ellipse, the value is less than 1. The conductive beads 22 in this embodiment are preferably “spherical” having an average circularity F in the range of 0.9 to 1.0. The circularity F can be obtained by image analysis or the like based on a microscopic image. Further, the ratio of the length of the major axis to the minor axis (minor axis / major axis) is preferably 1 (spherical) to 15 (elliptical). The ratio is not particularly limited unless the bonded body 20 is scratched or pierced.

The current collector is required to have diffusivity such as gas diffusibility as a supply path for raw materials such as raw material gas as well as electron conductivity for passing electrons during power generation in the joined body. The current collector 16 according to the present embodiment is filled with the conductive beads 22 so that the conductive beads 22 are in contact with the bonded body 20, and thus has electronic conductivity and is filled with the conductive beads 22. In addition, it has diffusibility due to the gap after being pressed.

The storage section 18 in FIG. 1 is not particularly limited as long as it has a bottomed shape capable of storing the entire joined body 20. For example, a bottomed cylindrical shape; a triangular cylinder, a square cylinder, a pentagonal cylinder The shape may be any shape such as a polygonal cylinder such as a hexagonal cylinder or an elliptical cylinder, but is usually a cylindrical shape. Examples of the material of the storage portion 18 include a resin such as polyether imide, a metal such as titanium, and the like. For example, a metal mesh (material: titanium) can be used.

Next, a method for manufacturing the fuel cell according to the present embodiment will be described with reference to FIG.

First, on a cylindrical support body 2 4 such as a Teflon (registered trademark) or other resin rod with good releasability, a metal rod coated with a Teflon (registered trademark) or other resin having good releasability, For example, the fuel electrode film is formed by a coating method such as a spray method or a dipping method. In the spray method, a paste in which a catalyst powder for a fuel electrode is dispersed in a solution obtained by dissolving a resin such as a solid polymer electrolyte such as naphthion (registered trademark) in an alcohol solvent such as methanol, ethanol or isopropanol. Is sprayed onto the support 24 to form a film having a desired thickness, and then dried. In the immersion method, the catalyst powder for the fuel electrode 12 is dispersed in a solution obtained by dissolving a resin such as a solid polymer electrolyte such as naphthion (registered trademark) in an alcohol solvent such as methanol, ethanol, or isopropanol. The substrate 24 is dipped in the paste 26 and pulled up (FIG. 3 (a)) to form a film having a desired thickness, and then dried.

Note that the shape of the support 24 may be selected according to the shape of the cylindrical joined body 20 to be manufactured. Further, the drying temperature may be a temperature that does not cause alteration of the catalyst, the electrolyte membrane, etc., depending on the boiling point of the solvent used. When isopropanol or the like is used, the temperature should be 80 to 100 ° C.

Next, in the same manner, an electrolyte membrane is formed on a support 24 on which a fuel electrode membrane is formed, using a paste 26 in which a solid polymer electrolyte or the like is dissolved in the solvent. In the same manner, a resin such as a solid polymer electrolyte such as naphthion (registered trademark) is dissolved in the above alcohol solvent on the support 24 on which the fuel electrode and the electrolyte membrane are formed. Using the paste 26 in which the air electrode catalyst powder is dispersed in the solution thus prepared, an air electrode film is formed to form a joined body 20.

The thus formed joined body 20 is taken out from the support 24 (FIG. 3 (b)), and a cylindrical joined body 20 having a fuel electrode on the inner surface of the electrolyte membrane and an air electrode on the outer surface. Is obtained.

Next, the thus obtained cylindrical joined body 20 is accommodated in a bottomed cylindrical accommodating portion 18 such as a metal mesh with its central axis aligned. Thereafter, the conductive beads 22 are filled into the inside of the joined body 20, and between the outside of the joined body 20 and the inside of the storage portion 18 (FIG. 3 (c)). At this time, the inside of the joined body 20, the outside of the joined body 20, and the inside of the housing portion 18 may be filled simultaneously, or may be filled separately. The conductive beads 22 are filled with a predetermined amount so as to contact a predetermined portion of the surface of the bonded body 20.

In addition, when filling the conductive beads 2 2, in order to fill the conductive beads 2 2 in a close-packed manner, the container 1 8 is vibrated and filled while applying vibration to the conductive beads 2 2. Is preferred. The vibration of the storage unit 18 is preferably performed so as to vibrate in the horizontal direction with respect to the central axis direction of the storage unit 18 and the joined body 20.

After filling a predetermined amount of the conductive beads 22, finally, the conductive beads 22 are pressed from the outside of the storage unit 18 using a stainless wire or the like (FIG. 3 (d)). By pressing, it is possible to prevent the conductive beads 22 from moving inside and outside the bonded body 20, and to further reduce the contact resistance between the bonded body 20 and the conductive beads 22. Further, the conductive beads 22 can be sufficiently functioned as a current collector without being sintered after being filled and pressed to form a sintered body. Since there is no need to sinter, it is not necessary to take into account the deterioration of the bonded body 20 due to sintering.

The pressure when pressing the conductive beads 2 2 is the catalyst layer (fuel electrode 1 2 and air electrode 1 4) is not particularly limited as long as the pressure does not damage or the conductive beads 22 do not break. For example, when pressing using stainless steel wire, 1 O kgf Zcm ² to 50 kgf Zcm ² The pressure is preferably.

In the fuel cell 1 shown in FIG. 1 manufactured as described above, the current collector 16 a formed inside the joined body 20 and the current collector 16 b formed outside the joined body 20 are removed. If it is electrically connected to the partial circuit and supplied with the raw material gas to the inside and outside of the joined body 20, it can be operated as a battery.

Examples of the raw material supplied to the fuel electrode 1 or 2 include reducing gas (fuel gas) such as hydrogen and methane or liquid fuel such as methanol. Examples of the raw material supplied to the air electrode 14 include oxidative gases such as oxygen and air.

In the fuel cell 1, for example, when the raw material supplied to the fuel electrode 1 2 is operated as hydrogen gas, and the raw material supplied to the air electrode 14 is operated as air,

2H ₂ → 4H ⁺ +4 e—

The hydrogen ion (H +) and the electron (e1) are generated from the hydrogen gas (H ₂ ) through the reaction formula shown in FIG. The electron (e1) passes from the current collector 16 a through the external circuit and reaches the air electrode 14 from the current collector 16 b. In the air electrode 14, oxygen (0 ₂ ) in the supplied air, hydrogen ions (H +) that have passed through the electrolyte membrane 10, and electrons (e 1) that have reached the air electrode 14 through an external circuit,

4H ⁺ +0 ₂ + 4 e— → 2H ₂ 0

Water is generated through the reaction formula shown in FIG. In this way, a chemical reaction occurs in the fuel electrode 12 and the air electrode 14, and electric charges are generated to function as a battery. And since the component discharged | emitted in a series of reaction is ice, a clean battery will be comprised.

When the raw material is supplied through the current collector 16 of the fuel cell 1, especially when the raw material is a gas, the difference in gas pressure between the raw material supply port of the current collector 16 and the raw material outlet of the current collector 16 ( When the pressure loss is small, there may be a difference in the concentration of the raw material gas supplied along the flow direction of the gas from the raw material supply port to the raw material outlet. In this case, as shown in FIG. It is preferable that the conductive beads 22 are filled so that the average particle diameter changes stepwise along the long axis direction of the cylindrical joined body 20, that is, along the flow direction of the source gas. Sile,. For example, by enlarging the gap in the portion near the material supply port of the current collector 16 and reducing the gap in the portion near the material outlet of the current collector 16 to increase the pressure loss, the source gas can be efficiently catalyzed. It can be distributed to the layers (fuel electrode 12 and air electrode 14). In this case, the average particle diameter of the conductive beads 22 is changed stepwise along the long axis direction of the cylindrical joined body 20 according to the pressure state of the raw material gas inside the current collector 16. It only needs to be filled, and it can be changed to two stages or can be changed to three or more stages.

For example, in order to increase the pressure loss, increase the gap in the portion near the raw material supply port of the current collector 16 and decrease the gap in the portion near the raw material outlet of the current collector 16 to increase the pressure loss. When changing the average particle size to three stages, the above method is used to first fill a predetermined amount of the conductive beads 22 with the smallest average particle size, and then add the second conductive beads 22 with the second average particle size. A predetermined amount is filled, and then a predetermined amount of conductive beads 22 having the largest average particle diameter is filled. Finally, the conductive beads 22 are pressed from the outside of the storage portion 18.

As described above, by filling the inner and outer sides of the cylindrical joined body 20 with the conductive beads 22 by the fuel cell and fuel cell manufacturing method according to the present embodiment, damage to the electrodes inside the cylinder is achieved. Thus, the current collector can be easily formed. This also prevents the carbon fiber 30 from sticking into the electrolyte membrane 32 and the catalyst layer 34 as shown in FIG. 6 and causing cross-leakage during power generation, thereby preventing power generation. Can do. Conventionally, there is also a method in which a catalyst layer and an electrolyte membrane are formed directly on a porous metal rod or metal wire as a current collector by the above-described paste or the like by a dipping method, a spray method, or the like. It was difficult to form a uniform joined body because the paste soaked into the pores of the solid metal rod and metal wire. However, after forming the uniform joined body 20 by the fuel cell and the fuel cell manufacturing method according to the present embodiment, the conductive beads 22 are filled, thereby collecting current without causing such a problem. The body 16 can be easily formed.

In addition, when a conventional porous metal, metal mesh, metal fiber cloth, or conductive felt is used as the current collector 16, the porosity is substantially constant with respect to the flow direction of the source gas. Although it was difficult to control the state of the pressure, as described above, if the current collector 1 6 is configured by changing the particle size of the conductive beads 22 to be filled in stages, the current collector 1 Since the porosity of 6 can be changed arbitrarily, Therefore, the diffusibility of the raw material can be controlled, and the raw material gas can be efficiently distributed to the catalyst layer.

The fuel cell according to the present embodiment can obtain necessary current and voltage by collecting a plurality of cylindrical fuel cells (single cells) and connecting them in series.

. A plurality of cylindrical fuel cells (single cells) may be assembled and connected in parallel.

Since the fuel cell according to the present embodiment has a simple structure and can be reduced in size and weight, it can be used as a small power source for mopile equipment such as a mobile phone and a portable personal computer;

[Example]

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail more concretely, this invention is not limited to a following example.

(Example 1)

Glued body fabrication>

Using a cylindrical Teflon (registered trademark) rod (diameter l mni, length 20 O mm) as a support, a fuel electrode, an electrolyte membrane, and an air electrode were formed in this order by an immersion method. For film formation, a paste in which carbon carrying platinum (P t) and ruthenium (R u) as a catalyst is dispersed in a 2-propanol solution of resin (Naphion, registered trademark) for the fuel electrode, electrolyte For membranes, perfluorosulfonic acid solid polymer electrolyte (Naphion, registered trademark) dissolved in 2_propanol Paste for air electrode, resin (Naphion, registered trademark) 2-propanol solution In addition, pastes in which carbon carrying platinum (Pt) was dispersed were used as catalysts. After each film formation, the film was dried in an oven at 80 ° C. for 60 minutes. The film thickness was 10 m for the fuel electrode, 4 ° m for the electrolyte film, and 10 μm for the air electrode. The joined body thus formed was taken out of the Teflon rod, and a cylindrical joined body having a fuel electrode on the inner surface of the electrolyte membrane and an air electrode on the outer surface was obtained.

<Filling with conductive beads> Next, the cylindrical joined body thus obtained was stored in a bottomed cylindrical metal mesh (material stainless steel, diameter 2 min, height 200 mm, mesh diameter 25 m) with the center axis aligned. After that, spherical conductive beads (material titanium, average particle size 30 μm, circularity of 0.99) are placed on the inside of the joined body, between the outside of the joined body and the inside of the metal mesh, Each of the inner and outer surfaces was filled so as to be almost filled. After filling a predetermined amount of conductive beads, finally, the conductive beads were pressed from the outside of the metal mesh using a stainless wire (pressure 30 kgf Zcm ² ) to obtain a fuel cell. No damage was observed on the fuel electrode and the air electrode. Hydrogen gas was supplied to the inside of the assembly, and air was supplied to the outside of the assembly. there were. Figure 5 shows the results of evaluating the battery performance of the obtained fuel cells.

(Example 2)

Filling with conductive beads>

The joined body obtained in Example 1 was stored in a cylindrical metal mesh with a bottom (material stainless steel, diameter 2 mm, height 200 mm, mesh diameter 25 m) with the center axis aligned. After that, spherical conductive beads (material titanium, average particle size 30 111, circularity 0.999) are placed on the inside of the joined body, between the outside of the joined body and the inside of the metal mesh, Each was filled up to 50mm from the bottom. Next, spherical conductive beads (material titanium, average particle size 100 μιη, circularity 0.9.9) are placed on the inside of the joined body, between the outside of the joined body and the inside of the metal mesh. Each was filled up to 150 mm from the bottom. Finally, a spherical conductive bead (material titanium, average particle size 1 50 μπι, circularity 0.9.9) is applied to the inside of the joint and between the outside of the joint and the inside of the metal mesh. Each of the metal meshes was filled up to 200 mm from the bottom.

After filling a predetermined amount of conductive beads, finally press the conductive beads using a stainless wire from the outside of the metal mesh (pressure 30 kgf / cm ² ), and set the average particle size of the conductive beads to 3 levels. The fuel cell changed in step 1 was obtained. No damage was seen in the fuel electrode and air electrode. Supply hydrogen gas inside the assembly and air outside the assembly However, the difference (pressure loss) in gas pressure between the current supply port of the current collector and the current outlet of the current collector is

It was 2 0 k Pa, which was larger than Example 1.

(Comparative Example 1)

Filling with conductive beads>

A porous metal wire (material: stainless steel) as a current collector was inserted into the joined body obtained in Example 1 between the inside of the joined body and between the outside of the joined body and the inside of the metal mesh. . Damage was seen in the fuel electrode and air electrode. Figure 5 shows the results of evaluating the battery performance of the obtained fuel cells.

Thus, the fuel cell of Example 1 has improved current-voltage characteristics compared to the fuel cell of Comparative Example 1, and in particular, a decrease of about 20% in concentration overvoltage is observed.

Claims

1. A cylindrical fuel cell,

A cylindrical electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and an air electrode provided on the other surface of the inner and outer surfaces of the electrolyte membrane. Coalesce,

A storage section for storing the tubular joined body;

A current collector formed by filling inside and outside of the cylindrical joined body with conductive beads.

Body,

A fuel cell comprising:

of

2. A fuel pond as claimed in claim 1,

Surrounding

The fuel cell according to claim 1, wherein the conductive beads have an average particle diameter that changes stepwise along a long axis direction of the cylindrical joined body.

3. A method of manufacturing a tubular fuel cell, comprising:

A cylindrical electrolyte membrane, a fuel electrode provided on one of the inner and outer surfaces of the electrolyte membrane, and an air electrode provided on the other surface of the inner and outer surfaces of the electrolyte membrane so as to face the fuel electrode A method of manufacturing a fuel cell, comprising forming a current collector by filling conductive beads on the inside and outside of a joined body having:

4. A method of manufacturing a fuel cell according to claim 3,

A method of manufacturing a fuel cell, wherein the conductive beads are filled while applying vibration.

5. A method of manufacturing a fuel cell according to claim 3 or 4,

A method for producing a fuel cell, comprising pressing the conductive beads after filling the conductive beads.

6. The method of manufacturing a fuel cell according to any one of claims 3 to 5, wherein the conductive beads are stepped in an average particle size along a major axis direction of the cylindrical joined body. A fuel cell manufacturing method, wherein filling is performed in a changing manner.