JP2004119189A - Fuel cell - Google Patents

Abstract

An object of the present invention is to provide a fuel cell capable of being thin, small, lightweight, and having a high degree of freedom in shape design.
SOLUTION: An anode panel 2 provided with a reducing gas inlet 22 and an outlet 23 through which reducing gas is supplied and discharged, a reducing gas flow path connecting the inlet 22 and the outlet 23, Cathode panel 1 provided with oxidizing gas inlets 12 and outlets through which gas is supplied and discharged, and oxidizing gas channels 1a, 1b, 1c connecting the inlets 12 and the outlets, and an anode panel 2 and a solid polymer electrolyte 4 sandwiched between the electrodes 14 formed on the cathode panel 1. The solid polymer electrolyte 4 is sandwiched between the anode panel and the cathode panel. Thus, the panel unit P is formed, and each of the panels 1 and 2 is formed in a plane, respectively, and corresponds to the surface of the gas flow path portion of each of the panels 1 and 2 where the solid polymer electrolyte is arranged And gold Forming the electrodes 14 by forming a film 14a.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell using a solid polymer electrolyte, and more particularly to a fuel cell that can be reduced in thickness.
[0002]
[Prior art]
Polymer fuel cells using solid polymer electrolytes such as polymer electrolytes have high energy conversion efficiency, and are thin, small and lightweight, and are being actively developed for home cogeneration systems and automobiles. . A conventional structure of such a fuel cell is disclosed in the following Non-Patent Document 1, which is shown in FIG.
[0003]
As shown in FIG. 4, an anode 101 and a cathode 102 are provided with a solid polymer electrolyte membrane 100 interposed therebetween. Furthermore, a unit cell 105 is formed by being sandwiched between a pair of separators 104 via a gasket 103. A plurality of the unit cells 105 are stacked, and the unit cells 105 are electrically connected in series to constitute a fuel cell N. The electrodes 106 can be taken out from the unit cells 105 at both ends of the stacked structure. Such a fuel cell N has attracted attention as a power source for electric vehicles and a distributed power source for home use in various applications because of its features of cleanness and high efficiency.
[0004]
[Non-patent document 1]
Nikkei Mechanical Separate Volume "Frontiers of Fuel Cell Development" Published on June 29, 2001, Published by Nikkei BP, Chapter 3, PEFC, 3.1 Principles and Features p46
[Problems to be solved by the invention]
On the other hand, with the development of IT in recent years, lithium-ion secondary batteries are used for most power supplies of mobile devices such as mobile phones, notebook computers, and digital cameras. However, power consumption tends to increase steadily as these mobile devices become more sophisticated, and attention has been paid to clean and highly efficient fuel cells for power sources.
[0005]
However, the conventional structure as shown in FIG. 4 has no flexibility in structure, and thus has difficulty in reducing the thickness, size, and weight required for a power source of a mobile device and increasing the degree of freedom in shape.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel cell capable of being thin, small, lightweight, and having a high degree of freedom in shape design.
[Means for Solving the Problems]
To solve the above problems, a fuel cell according to the present invention is
An oxidizing gas inlet / outlet through which an oxidizing gas is supplied / discharged, and a cathode panel provided with an oxidizing gas flow path connecting the inlet and the outlet,
A reducing gas inlet / outlet through which reducing gas is supplied / discharged, and an anode panel provided with a reducing gas flow path connecting the inlet and the outlet,
An electrode formed on the anode panel and a solid polymer electrolyte held between the electrodes formed on the cathode panel are provided, and the solid polymer electrolyte is held between the anode panel and the cathode panel. To form a panel unit,
Each of the panels is formed in a planar shape, and the electrode is formed by forming a metal coating on the surface of the gas flow path portion of each panel, corresponding to the region where the solid polymer electrolyte is disposed. It is characterized by forming.
[0007]
The operation and effect of the fuel cell having this configuration are as follows. That is, a panel unit is configured by sandwiching the solid polymer electrolyte between the anode panel and the cathode panel. Each of the panels has a gas flow path for an oxidizing gas or a reducing gas. In each panel, an electrode is formed by a metal film in a gas flow path portion. Since the electrode is formed of a metal film, the thickness can be reduced. In addition, it is made of a metal film and can correspond to various shapes of the panel. Therefore, the degree of freedom of design increases by devising the arrangement of the inlet and outlet of the gas flow path and the way of taking the gas flow path. Further, since each panel is flat and the electrodes are also made of a metal film, the panel unit can be made thin. As a result, it is possible to provide a fuel cell that can be made thin, small, lightweight, and has a high degree of freedom in shape design.
As a preferred embodiment of the present invention, each of the panels has a plurality of electrodes arranged in a plane.
[0008]
By arranging in a plane, output can be earned. In addition, by arranging them in a plane, it is possible to increase the output while maintaining the thinness. The shape can be freely changed by changing the arrangement in a plane.
[0009]
As another preferred embodiment of the present invention, there is a panel in which each of the panels is formed in a rectangular shape, the plurality of electrodes are linearly arranged, and each electrode is provided on a long side of the rectangle. Can be
[0010]
By forming each panel in a rectangular shape and taking out the electrodes from the long side of the rectangle, the electrodes can be taken out while keeping the panel unit thin.
[0011]
In another preferred embodiment of the present invention, a plurality of the panel units are stacked in layers.
The output can also be increased by stacking the panel units in layers.
[0012]
As still another preferred embodiment of the present invention, there is a method in which the metal film is formed by vapor deposition. Thereby, the panel unit can be made thin.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
A preferred embodiment of a fuel cell according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an assembly structure of a fuel cell. FIG. 2 is a diagram showing a cross-sectional shape of the panel. FIG. 3 is a diagram illustrating a cross-sectional shape of the electrolyte holding unit.
[0014]
The panels are formed in a planar shape, and there are two panels for reducing gas (for example, hydrogen gas) and for oxidizing gas (for example, oxygen gas), but both have the same shape. The cathode panel 1 is provided with a gas inlet 12 into which an oxidizing gas is injected and a gas outlet. The panel 1 has a first gas passage 1a, a second gas passage 1b, and a third gas passage 1c. The anode panel 2 is also provided with a gas inlet 22 into which the reducing gas is injected and a gas outlet 23. The panel 2 also has the same gas flow path as the panel 1.
[0015]
In the panel 1, the first gas passage 1a and the second gas passage 1b are formed parallel to each other. The panels 1 and 3 are formed by resin molding, and the gas flow paths 1a to 1c are also integrally formed. A through hole 12 a is formed at an end of the first gas flow path 1 a and communicates with the gas inlet 12. A through hole 13a is also formed at the end of the second gas flow path 10b, and communicates with the gas discharge port. A large number of third gas flow paths 1c are arranged orthogonal to the first and second gas flow paths 1a and 1b.
[0016]
On the panels 1 and 2, five electrodes 14 are formed side by side in a plane. The electrode 14 is formed of a metal coating 14a on the surface of the region where the second gas passage 1b and the third gas passage 1c are formed. The metal film 14a is also formed on the groove bottoms of the gas flow paths 1b and 1c. The metal film 14a is preferably formed by metal deposition, but is not limited to this, and may be formed by metal plating, CVD, or the like. As the metal, gold or platinum is preferable. The electrode take-out part 14b is provided on the long sides of the panels 1 and 2 formed in a rectangular shape. In consideration of connection to an electric circuit, the take-out part 14b of the cathode panel 1 and the take-out part 14c of the anode panel 2 take out electrodes from the long sides in different directions. In addition, in order to facilitate connection with an electric circuit, it is preferable that the end surface of the extraction portion 14b is formed to protrude more than the end surface of the membrane electrode assembly 4 and the anode panel 2 in the same direction. The same applies to the other take-out unit 14c.
[0017]
The electrode 14 of the cathode panel 1 and the electrode of the anode panel 2 face each other, and the electrolyte held by the electrolyte holding unit 4 is sandwiched therebetween. As shown in FIG. 3, a solid electrolyte membrane 40 (for example, a polymer electrolyte) is sandwiched between a cathode membrane electrode 41 and an anode membrane electrode 42, and these are held by a rubber elastic body 43. The electrodes 41 and 42 and the solid electrolyte membrane 40 constitute a membrane electrode assembly. Membrane electrode assemblies are prepared by the number of electrodes 14 to be attached.
[0018]
As described above, the panel unit P is obtained by laminating the cathode panel 1, the electrolyte holding unit 4, and the cathode panel 2 on each other. Lamination can be performed by a method such as ultrasonic fusion or heat fusion. Only this panel unit P can be used as a fuel cell. Further, a fuel cell in which the panel units P are stacked in layers may be used.
[0019]
【Example】
Next, more specific materials and dimensions of the fuel cell described above will be described. Each of the panels 1 and 2 is formed of a polymer resin sheet having electric insulation or a sheet having rigidity and electric insulation made by combining a metal and a polymer resin, and has a size of 93 mm × 27 mm. × 0.4 mm thick. The groove size of the gas flow channel formed in each of the panels 1 and 2 is 0.6 mm in width and 0.2 mm in depth.
[0020]
The size of the membrane electrode assembly is 15 mm × 15 mm, and the thickness is 0.2 mm. The thickness of the rubber elastic body is the same. Five membrane electrode assemblies were prepared as shown in FIG.
[0021]
This electrolyte holding unit was produced as follows. First, a platinum catalyst, carbon black (Ketjen Black EC, Akzo) and polyvinylidene fluoride (Kyner) were mixed at 75% by weight, 15% by weight, and 10% by weight, respectively, and dimethylformamide was added at 2.5% by weight. % Of a polyvinylidene fluoride solution was added to the mixture of the platinum catalyst, carbon black, and polyvinylidene fluoride, and dissolved and mixed in a mortar to prepare a catalyst paste. As the platinum catalyst, a 20% platinum-supported carbon catalyst (EC-20-PTC) manufactured by Electrochem, USA was used. Carbon paper (TGP-H-90, manufactured by Toray) is cut into 10 mm squares, and about 20 mg of the catalyst paste prepared as described above is applied thereon with a spatula, and is dried in a hot air circulating drier at 80 ° C. Dried. Thus, a carbon paper carrying 4 mg of the catalyst composition was produced. The platinum carrying amount is 0.6 mg / cm ² .
[0022]
Two platinum catalyst-carrying carbon papers prepared as described above were used as solid electrolyte membranes using a 13 mm square Nafion film (Nafion 112 manufactured by DuPont), and a mold on both sides at 135 ° C. and 2 MPa. For 2 minutes. The electrode membrane assembly obtained in this manner was mounted in the above-mentioned opposing panel.
[0023]
In this way, a thin and small micro fuel cell having an outer dimension of 93 mm × 27 mm × 1 mm was obtained. That is, since the thickness of each of the panels 1 and 2 is 0.4 mm, the thickness of the panel unit P is 0.4 + 0.4 + 0.2 = 1 mm.
[0024]
The cell characteristics of this micro fuel cell were evaluated. The fuel cell characteristics were evaluated using a fuel cell evaluation system manufactured by Toyo Technica at room temperature using pure hydrogen gas and pure oxygen gas. The gas flow rate was 100 mL / min. The obtained maximum power density was 70 mW / cm ² per electrode area. By electrically connecting the five electrodes, an output of 350 mW was obtained as the micro fuel cell according to the present invention.
[0025]
As described above, according to the present invention, it was possible to provide a micro fuel cell capable of designing a thin, small, lightweight, and highly flexible shape. Further, by stacking a plurality of structures (panel units) according to the present embodiment, a fuel cell with higher output can be obtained.
[0026]
<Another embodiment>
(1) In the present embodiment, five electrodes 14 are arranged side by side, but the present invention is not limited to this. The number to arrange is arbitrary. The direction in which they are arranged does not need to be straight, and they can be arranged appropriately. This increases the degree of freedom in design.
[0027]
(2) The materials of the panels 1 and 2 and the electrolyte holding unit 4 constituting the fuel cell are not limited to specific types of materials. For example, as a constituent material of the panels 1 and 2, an appropriate resin material can be used. Panels 1 and 2 may be formed not only by a single resin sheet but also by bonding a resin sheet and a metal sheet. In this case, the resin and the metal material can be appropriately selected.
[Brief description of the drawings]
FIG. 1 is a view showing an assembly structure of a fuel cell. FIG. 2 is a view showing a cross-sectional shape of a panel. FIG. 3 is a view showing a cross-sectional shape of an electrolyte holding unit. FIG. 4 is a view showing a configuration of a fuel cell according to a conventional technique. Figure [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cathode panel 1a, 1b, 1c Gas flow path 2 Anode panel 4 Electrolyte holding unit 12 Oxidizing gas inlet 14 Electrode 14a Metal coating 14b, 14c Take-out part 22 Reduction gas inlet 23 Reduction gas outlet 40 Solid polymer electrolyte 41 Membrane electrode for cathode 42 Membrane electrode for anode 43 Rubber elastic body P Panel unit

Claims (5)

An oxidizing gas inlet / outlet through which an oxidizing gas is supplied / discharged, and a cathode panel provided with an oxidizing gas flow path connecting the inlet and the outlet,
A reducing gas inlet / outlet through which reducing gas is supplied / discharged, and an anode panel provided with a reducing gas flow path connecting the inlet and the outlet,
An electrode formed on the anode panel and a solid polymer electrolyte held between the electrodes formed on the cathode panel are provided, and the solid polymer electrolyte is held between the anode panel and the cathode panel. To form a panel unit,
Each of the panels is formed in a planar shape, and the electrode is formed by forming a metal coating on the surface of the gas flow path portion of each panel, corresponding to the region where the solid polymer electrolyte is disposed. A fuel cell, comprising: 2. The fuel cell according to claim 1, wherein a plurality of electrodes are arranged on each of the panels in a plane. The fuel cell according to claim 2, wherein each of the panels is formed in a rectangular shape, the plurality of electrodes are linearly arranged, and each electrode is provided on a long side of the rectangle. The fuel cell according to any one of claims 1 to 3, wherein a plurality of the panel units are stacked in layers. The fuel cell according to any one of claims 1 to 4, wherein the metal film is formed by vapor deposition.

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