JP2004265872A - Fuel cell, fuel cell generator and instrument using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact power source without using a separator and supplemental device like a fluid supplying mechanism, most suitable for portable use. <P>SOLUTION: The fuel cell has an anode 3 oxidizing a liquid fuel, a cathode 4 reducing oxygen, and an electrolyte film 2 insulating the anode 3 from the cathode 4. The fuel cell is structured in a hollow support body, and the power generating part is constructed by arranging the anode 3, the electrolyte film 2, and the cathode 4 on a peripheral surface of the hollow support body 1. The fuel cell is constructed so that the power generating part contacts the fuel at the outside of the hollow support body and contacts oxygen at the inside thereof. A fuel cell generator and an instrument using the fuel cell are provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a fuel cell comprising an anode, an electrolyte membrane, a cathode, and a diffusion layer, wherein fuel is oxidized at the anode and oxygen is reduced at the cathode. In addition, the present invention relates to a power generation device including such a fuel cell, a small portable power supply, and an electric device or an electronic device using such a power supply.

  With the advance of electronic technology, the rapid spread of telephones, book-type personal computers, audio-visual devices, or electric devices such as mobile information terminal devices, electronic devices, and miniaturized portable electronic devices has been progressing. I have.

  Conventionally, such a portable electronic device has been a system driven by a primary battery or a secondary battery. Secondary batteries have been developed from sealed lead batteries to Ni / Cd batteries, Ni / hydrogen batteries, and even Li-ion batteries by the appearance of new types of secondary batteries, and downsizing / lightening and high energy density technologies. However, secondary batteries must be charged after a certain amount of power is used, and charging equipment and charging time are required. Therefore, many problems remain for long-term continuous operation of portable electronic devices. I have. In the future, portable electronic devices are going to require a power source with a higher energy density, that is, a power source with a long continuous use time, in response to an increasing amount of information and its speeding up. The need for generators (micro-generators) is increasing.

  In response to such demands, fuel cell power supplies have been proposed. Fuel cells convert the chemical energy of a fuel electrochemically directly into electrical energy. It does not require a power unit such as that using an internal combustion engine such as a normal engine generator, and has the potential as a small power generation device. In addition, since the fuel cell can continue generating power only by refueling, it is not necessary to stop the operation of the portable electronic device in use for charging as seen in the conventional secondary battery. And can be.

Among such fuel cells, a polymer electrolyte fuel cell (PEFC) that oxidizes hydrogen gas at an anode using a perfluorocarbon sulfonic acid-based electrolyte membrane and reduces oxygen at a cathode to generate power is used. Are known as high power density batteries.

  In order to further reduce the size of this fuel cell, for example, as shown in JP-A-9-223507, an assembly of a cylindrical cell having an anode and a cathode on the inner surface and the outer surface of a hollow-fiber electrolyte is provided. And a small-sized PEFC power supply for supplying hydrogen gas and air to the outside, respectively.

  However, when applied to the power supply of a portable electronic device, since the fuel is hydrogen gas, the volume energy density is low, and it is necessary to increase the volume of the fuel tank.

  In addition, this system requires auxiliary equipment such as a device that feeds fuel gas or oxidizing gas (such as air) to the power generation device, and a device that humidifies the electrolyte membrane to maintain battery performance. This configuration is not enough to reduce the size of the power supply.

In order to increase the volume energy density of the fuel, it is effective to use a liquid fuel, and to adopt a simple configuration that eliminates an auxiliary device for supplying a fuel or an oxidant to a battery, and several proposals have been made. As a recent example, a direct methanol fuel cell (DMFC: DMFC :) using methanol and water as fuel as disclosed in JP-A-2000-268835 and JP-A-2000-268836.
Direct Methanol Fuel Cell) has been proposed.

  This power generation device is configured such that an anode is disposed in contact with an outer wall side of a liquid fuel tank via a material for supplying liquid fuel by capillary force, and a solid polymer electrolyte membrane and a cathode are sequentially joined. ing. Since oxygen is supplied by diffusion of oxygen to the cathode outer surface that comes into contact with the outside air, according to this method, the power generator has a simple configuration that does not require auxiliary equipment for supplying fuel and oxidizing gas. .

  However, since the output voltage of the DMFC under load is 0.3 to 0.4 V per unit battery, the number of fuel tanks provided with fuel cells corresponding to the voltage required by portable electronic devices and the like is mounted and each battery is mounted. Must be connected in series. Therefore, in order to reduce the size of the power generation device, there is a problem that as the number of series-connected batteries increases, the fuel tank capacity decreases, and the number of fuel tanks is dispersed according to the number of series.

  An object of the present invention is to provide a fuel cell power generation device that can easily continue power generation by replenishing fuel without being charged every time a certain amount of power is consumed as in a secondary battery as power is used. Another object of the present invention is to provide a system using a fuel having a high volume energy density.

  Another object of the present invention is to provide a compact and portable power source and a portable power source using the same without using auxiliary equipment such as a fluid supply mechanism for forcibly flowing fuel and oxidizing gas. It is to provide an electronic device.

  In order to achieve the above object, a feature of the present invention is a fuel cell having an anode for oxidizing a liquid fuel, a cathode for reducing oxygen, and an electrolyte membrane insulating the anode and the cathode, The battery has a hollow support structure, and an anode, an electrolyte membrane, and a cathode are arranged on an outer peripheral surface of the hollow support to form a power generation unit. The fuel is generated inside the hollow support and the fuel is generated outside the power generation unit. In a fuel cell in contact with a gas containing oxygen.

  Another feature of the present invention is a fuel cell having an anode for oxidizing a liquid fuel, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode, wherein the fuel cell is a hollow support. A fuel cell unit having a plurality of fuel cells having a structure and having a power generation unit formed by arranging an anode, an electrolyte membrane, and a cathode on the outer peripheral surface of the hollow support; and a container for storing the liquid fuel. Wherein each of the power generation units is electrically connected, and the liquid fuel is supplied from the container to the inside of the hollow support structure to generate electric power.

  A small fuel cell power supply according to the present invention is a liquid fuel fuel cell having an anode for oxidizing fuel and a cathode for reducing oxygen through an electrolyte membrane, and a hollow support having a container for storing liquid fuel as a platform. A fuel cell unit having a power generation unit in which an anode, an electrolyte membrane, and a cathode are arranged is connected to an outer peripheral surface of the fuel cell unit, and the fuel cell units are electrically connected in series or in parallel.

  In particular, when the required current is relatively small and a high voltage is required, a fuel cell unit having a plurality of power generation units having an anode, an electrolyte membrane, and a cathode arranged on the outer peripheral surface of the hollow support is used, and each of the power generation units is electrically conductive. High voltage can be achieved by connecting in series with a flexible interconnector.

  Fuel is supplied to the interior of the hollow support without using a forced supply mechanism by connecting the fuel tank as a platform, and at this time, the liquid fuel is held in the hollow support and refilled by filling with the material that is drawn up by capillary force. Is more stabilized. On the other hand, each fuel cell unit having a power generation unit on the outer peripheral surface of the hollow support is supplied with an oxidant by diffusion of oxygen in the air. By using a methanol aqueous solution having a high volume energy density as a liquid fuel, power generation can be continued for a longer time than when hydrogen gas is used as a fuel in a tank having the same volume.

  The power supply according to the present invention is used as a battery charger attached to charge a portable telephone, a portable personal computer, a portable audio device, a visual device, and other portable information terminals equipped with a secondary battery at rest or a secondary battery. These electronic devices can be used for a long time by directly using a built-in power supply without mounting a, and can be used continuously by refueling.

  According to the present invention, when a required current is relatively small and a high voltage is required, a fuel cell unit having a plurality of power generation units in which an anode, an electrolyte membrane, and a cathode are arranged on an outer peripheral surface of a hollow support is provided. Since the power generation units can be connected in series by a conductive interconnector, a high voltage can be achieved, and a small fuel cell power generation device can be realized.

  Fuel is supplied without the use of a forced supply mechanism inside the hollow support by coupling the fuel tank as a platform. At this time, the fuel is supplied by holding the liquid fuel in the hollow support and filling it with a material that is sucked up by capillary force. Each fuel cell unit having a power generation unit on the outer peripheral surface of the hollow support diffuses oxygen in the air. The oxidizing agent is supplied by this, and a simple system that does not require auxiliary equipment for supplying the fuel and the oxidizing agent can be configured.

  In addition, by using a methanol aqueous solution with a high volume energy density as a liquid fuel, power generation can be continued for a longer time than when hydrogen gas is used as a fuel in a tank of the same volume. A continuous power generator that does not require a charging time like a secondary battery can be realized.

  The power supply according to the present invention is used as a battery charger attached to a portable telephone, a portable personal computer, a portable audio device, a visual device, and other portable information terminals equipped with a secondary battery, or directly built in without a secondary battery. By using a power supply, these electronic devices can be used for a long time, and can be used continuously by refueling.

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1A schematically shows the structure of a fuel cell unit constituting one embodiment of the present invention, and FIG. 1B shows an external view of the fuel cell unit, showing one wall cross-sectional structure thereof. I do.

  An outer peripheral portion of the hollow rectangular support 1 is coated with an anode current collector 6, and an anode electrode 3, an electrolyte 2, a cathode electrode 4, a diffusion layer 5, and a cathode current collector 7 are sequentially superposed and joined thereon. To form a power generation unit. This is a fuel cell, a fuel cell unit or a unit cell. As will be described later, a combination of a plurality of these fuel cell units is referred to as a fuel cell module or a module battery.

  At this time, the wall surface of the hollow support 1 coated with the anode current collector to which the anode is joined has a penetrating mesh or penetrating porous wall surface structure so that the liquid fuel supplied into the cylinder comes into contact with the anode. ing. FIG. 2A shows the configuration of a power supply in which a fuel supply port and fuel outlets 9 and 10 are connected to a fuel tank 102 using a fuel cell module 101 composed of a plurality of fuel cell units as a platform. FIG. 2 (b) shows a cross-sectional view of the state when they are combined.

  The fuel tank 102 is provided with a fuel supply port 103 at an upper portion, and holds an aqueous methanol solution as fuel 104 inside. In this way, the fuel is supplied into the hollow support without using a forced supply mechanism. At this time, the fuel supply can be further stabilized by holding the liquid fuel in the hollow support and filling the liquid holding material 14, which is a material sucked up by the capillary force.

  On the other hand, as shown in FIG. 1B, the cathode electrode 4 has a structure in which it is supplied by diffusion of oxygen in the atmosphere through a porous cathode current collector 7 and a diffusion layer 5, so that the oxidizing gas is forcibly supplied. Receives supply without using a supply mechanism.

  In a fuel cell using a methanol aqueous solution as a fuel, power is generated in such a manner that chemical energy possessed by methanol is directly converted into electric energy by the following electrochemical reaction. On the anode electrode side, the supplied aqueous methanol solution reacts according to the equation (1) to dissociate into carbon dioxide, hydrogen ions and electrons.

CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ (1)
The generated hydrogen ions move from the anode to the cathode side in the electrolyte membrane, and react with oxygen gas diffused from the air on the cathode electrode and electrons on the electrode according to the formula (2) to generate water.

6H ⁺ + 3 / 2O ₂ + 6e ⁻ → 3H ₂ O (2)
Therefore, as shown in equation (3), the entire chemical reaction associated with power generation oxidizes methanol with oxygen to produce carbon dioxide gas and water, and the chemical reaction equation is the same as that of flame combustion of methanol.

CH ₃ OH + 3 / 2O ₂ → CO ₂ + 3H ₂ O (3)
The open-circuit voltage of the unit cell is approximately 1.2 V, and is substantially 0.85 to 1.0 V due to the effect of fuel permeating the electrolyte membrane. Although not particularly limited, the voltage under practical load operation is not limited. Is selected in the range of about 0.3 to 0.6 V. Therefore, when actually used as a power supply, unit batteries are used in series so that a predetermined voltage can be obtained according to the requirements of the load equipment. Although the output current density of the unit cell changes due to the effects of the electrode catalyst, the electrode structure, and the like, the unit is designed so that the power generation unit area of the unit cell is effectively selected to obtain a predetermined current. Also, the battery capacity can be adjusted by connecting them in parallel as appropriate.

  Here, the support constituting the fuel cell unit is characterized in that it has a cylindrical structure, which is one of the hollow support structures, but its cross section may be square, circular or any other shape. There is no particular limitation as long as the shape of the power generation unit can be sufficiently obtained.

  However, in order to load the fuel cell unit compactly in a prescribed volume, the cylindrical type and the square type have good filling efficiency, and can be said to be preferable shapes in terms of workability for mounting the fuel cell power generation unit.

  The support material may be any material that is electrochemically inert, durable and thin enough to have sufficient strength under the use environment. For example, polyethylene, polypropylene, polyethylene terephthalate, vinyl chloride, polyacrylic resin and other engineering resins, electrically insulating materials obtained by reinforcing these with various fillers, carbon materials having excellent corrosion resistance in an atmosphere in which generated water is generated, An electrically conductive material obtained by subjecting the surface of stainless steel, or ordinary iron, nickel, copper, aluminum or an alloy thereof to a corrosion-resistant treatment can be used.

  It is also effective to use an insulating material in which a base metal having poor corrosion resistance is coated with the above resin. In any case, the material is not particularly limited as long as it is a material that supports the shape, has corrosion resistance, and is electrochemically inert.

  The inside of the cylindrical support is used as a fuel transport space, but the wicking material that stabilizes the fuel supply filled inside the cylindrical support has a small contact angle with aqueous methanol solution, is electrochemically inert and corrosion resistant Any material may be used, and a powder or fibrous material may be used. For example, fibers such as glass, alumina, silica-alumina, silica, non-graphitic carbon, cellulose, and water-absorbing polymer fibers are preferable materials having a low packing density and excellent methanol aqueous solution retention.

  As an anode catalyst constituting a power generation unit, a carbon-based powder carrier in which platinum and ruthenium or platinum / ruthenium alloy fine particles are dispersed and supported, and a cathode catalyst in which a carbon-based carrier has platinum fine particles dispersedly supported are easily manufactured and used. It is a material that can be made.

  The catalyst of the anode and the cathode of the fuel cell according to the present invention is not particularly limited as long as it is used for a normal direct methanol fuel cell. A membrane exhibiting hydrogen ion conductivity is used as the electrolyte membrane. Examples of such materials include sulfonated fluoropolymers typified by polyperfluorostyrene sulfonic acid and perfluorocarbon sulfonic acid, and carbonized materials such as polystyrene sulfonic acid, sulfonated polyether sulfones, and sulfonated polyether ether ketones. A material obtained by sulfonating a hydrogen-based polymer can be used. If these materials are used as the electrolyte membrane, the fuel cell can generally be operated at a temperature of 80 ° C. or less.

  In addition, by using a composite electrolyte membrane in which hydrogen ion conductive inorganic substances such as tungsten oxide hydrate, zirconium oxide hydrate, and tin oxide hydrate are micro-dispersed in a heat-resistant resin, the temperature can be increased to higher temperatures. It can also be an operating fuel cell. In any case, when an electrolyte membrane having high hydrogen ion conductivity and low methanol permeability is used, the power generation utilization rate of the fuel is increased, so that the effects of the present invention such as compactness and long-term power generation can be achieved at a higher level. Can be.

  The power generation unit constituting the fuel cell unit can be manufactured by, for example, the following method. That is, 1) a step of applying a conductive current collector plate to the outer peripheral surface of the hollow support to make the wall surface of the anode junction porous by through holes, and 2) volatilizing the same material as the anode catalyst and the electrolyte membrane in advance. A process of adding a solution dissolved in an organic solvent as a binder, dispersing the solution into a paste, and applying the resulting solution to a constant thickness of 10 to 50 μm on a porous portion of a hollow support to form an electrode; Applying an electrolyte solution dissolved in a volatile organic solvent on the anode electrode so that the thickness after film formation is 20 to 50 μm. 4) Then, the same substance as the cathode catalyst and the electrolyte membrane is previously added to the volatile organic solvent. A step of applying a solution obtained by kneading the dissolved solution as a binder into a paste to form a fixed thickness of 10 to 50 μm on an electrolyte membrane to form an electrode; Water repellency An aqueous dispersion of the dispersion material such as polytetrafluoroethylene fine particles in the paste is applied to the surface of the cathode electrode fuel cell unit is made through a process of forming the diffusion layer.

  At this time, in step 3), it is important that the electrolyte membrane portion is larger than the cathode area, and it is important that the support and the electrolyte membrane are adhered to each other or sealed by bonding using an adhesive. A terminal is taken out as a cathode current collector by attaching a conductive porous material or net to the cathode portion of the obtained fuel cell unit, and a terminal is taken out from the anode current collector.

  When the fuel cell unit is composed of a single fuel cell, the step 1) is not required, and the anode terminal can be directly taken out using the conductive hollow support. Further, in the case where the water-repellent aqueous dispersion material contains a platinum catalyst or a surfactant which is a catalyst poison component of a platinum-ruthenium alloy catalyst, for example, a conductive woven fabric surface such as carbon fiber is used. One side is coated with a carbon-based powder and a predetermined amount of an aqueous dispersion of a water-repellent dispersant, for example, polytetrafluoroethylene fine particles, applied in the form of a paste, fired in advance at a temperature at which the surfactant is decomposed, and then the coated surface is brought into contact with the cathode It is effective to use a carbon fiber woven fabric as a cathode terminal.

  In addition, a cylindrical electrolyte membrane is coated in advance with an anode of a predetermined thickness on the inner surface, and a cathode and a diffusion layer are coated on the outer surface to form an electrode-electrolyte membrane assembly (Membrane Electrode Assembly). The anode, the electrolyte membrane, the cathode, and the water-repellent layer may be individually formed in a cylindrical shape in advance, or some of them may be combined and joined to form a cylindrical shape, and then sequentially mounted on a support. It is valid.

Alternatively, an electrode / electrolyte membrane assembly (Membrane
It is also effective to wind the electrode support around the outer periphery of the cylindrical support, join the joints of the electrolyte membranes, and mount them.

  However, since the joining of the anode, the electrolyte membrane, and the cathode is a step of forming a reaction interface between the electrodes, it is desirable to join them in advance by applying the anode and the cathode to the electrolyte.

  In any case, a method is used in which a fuel cell unit is stacked on a support in the order of an anode, an electrolyte membrane, a cathode, and a water-repellent layer, and forms a sufficient reaction interface between the anode / electrolyte membrane and the cathode / electrolyte membrane. There are no special restrictions on the method. Further, when forming the cathode, a predetermined amount of a water-repellent dispersion material, for example, polytetrafluoroethylene fine particles is added to a solution in which the same substance as the cathode catalyst and the electrolyte membrane is dissolved in a volatile organic solvent in advance, and the paste is applied. Can form a battery that does not require a water-repellent layer.

  Next, regarding the structure for obtaining a higher voltage per fuel cell unit, FIG. 3A shows the appearance of such a fuel cell unit, and FIG. explain.

  In this case, the hollow support 1 needs to be formed of a material having an electrical insulation property, and a mesh-like or porous material that forms a power generation portion of the hollow cylindrical support 1 coated with the conductive anode current collector plate 6. The plurality of layers 8 are provided in a stripe pattern on the outer periphery. A fuel outlet 9 and a supply port 10 are provided above and below the fuel cell unit. The configuration of the unit battery is such that a conductive porous anode current collector 6, an anode 3, an electrolyte membrane 2, a cathode 4, a diffusion layer 5, a mesh or porous cathode current collector 7 are stacked in this order from the outer wall surface of the support. The cathode current collector is formed, and each battery is connected in series to an adjacent anode current collector via an interconnector 11. The unit battery is formed by the same method as described above. The output terminals are drawn from the anode current collector 6 at one end and the cathode current collector 7 at the other end.

  The fuel tank is a structure that also serves as a platform of a power generation device including one or more cylindrical fuel cells. For the fuel tank, a material having structural strength and particularly corrosion resistance to an aqueous methanol solution is used. Polyethylene, polypropylene, polyethylene terephthalate, vinyl chloride, polyacrylic resin, other engineering resins, or electrically insulating materials obtained by reinforcing these with various fillers, or stainless steel, or ordinary iron, nickel, copper, or aluminum And materials obtained by subjecting the surfaces of their alloys to corrosion treatment.

  It is also effective to use a material in which a base metal having poor corrosion resistance is coated with the above resin. The fuel tank has one or more fuel supply ports having mounting ports for coupling with fuel supply and discharge holes of a plurality of fuel cell units. The fuel supply and discharge ports need only be an airtight mechanism, and the structure is not particularly limited. In particular, if this coupling is a detachable mechanism, the power supply can be used for a long time by replacing the entire fuel cell module or a specific fuel cell unit when a part of the fuel cell unit is deteriorated or other trouble occurs. This is a preferable structure.

  At the time of power generation, the aqueous methanol solution in the fuel cell unit is oxidized to generate carbon dioxide gas and returned from the fuel cell unit outlet to the fuel tank, so that the tank internal pressure increases. Further, the pressure in the fuel tank rises due to the power source moving from a low temperature to a high temperature environment due to a change in environmental temperature. In order to avoid such a situation, it is effective to provide a gas selective transmission mechanism at the fuel supply port.

  Further, as another embodiment, in addition to the fuel tack serving as a platform of the fuel cell unit group, a structure in which an auxiliary fuel tank can be mounted on the platform may be employed for the purpose of extending the power generation duration. In this case, it is preferable to use a platform tank provided with a receiving port mechanism and an auxiliary tank provided with a fuel supply port having a mounting port mechanism and a gas selective transmission mechanism.

  FIG. 4 shows a cross-sectional structure as a specific embodiment of the gas selective permeation mechanism. A plate having one or more pinholes whose inner surface is made water-repellent or a porous water-repellent plate 52 is sandwiched between the lid portions 51 of the fuel supply port 53. The lid 51 and the fuel supply port 53, and the fuel supply port and the fuel tank are fixed by an airtight screw structure. When the gas pressure in the tank rises due to generation of carbon dioxide gas due to power generation or an increase in environmental temperature, the gas is selectively transmitted and discharged through the multi-pinhole or the porous plate, and the liquid fuel does not flow out.

  A fuel cell unit having a plurality of power generation units having an anode, an electrolyte membrane, and a cathode disposed on the outer peripheral surface of a hollow support which is a feature of the present invention is manufactured, and each power generation unit is connected in series by a conductive interconnector. By using a fuel tank as a platform, the fuel is supplied to the hollow support without using a forced supply mechanism, and each fuel cell unit is supplied with an oxidizing agent by diffusion of oxygen in the air from the outer surface. By using a methanol aqueous solution having a high volume energy density as a liquid fuel, it is possible to realize a small power source that can continue power generation for a long time. This small power supply can be driven by being built in, for example, as a power supply for a mobile phone, a book-type personal computer, or a portable video camera, and can be continuously used for a long time by sequentially replenishing fuel prepared in advance. .

  Further, in order to use the fuel supply frequency significantly less than in the above-described case, the small power supply is connected to a charger for a mobile phone, a book-type personal computer or a portable video camera equipped with a secondary battery, for example. It is effective to use it as a battery charger by attaching it to a part of the storage case. In this case, when the portable electronic device is used, it is taken out of the storage case and driven by the secondary battery, and when not in use, it is stored in the case, so that the small fuel cell power generation device built in the case is connected via the charger to the secondary battery. Charge the next battery. By doing so, the capacity of the fuel tank can be increased, and the frequency of refueling can be significantly reduced.

  The present invention will be described in more detail with reference to the following examples, but the gist of the present invention is not limited to the examples disclosed herein.

  Hereinafter, a first embodiment of the present invention will be described.

  FIG. 5A shows an external structure of a prismatic fuel cell unit according to an embodiment of the present invention, and FIG.

  The hollow support 1 is made of stainless steel SUS304 having a thickness of 0.4 mm and coated with a hydroxyl group-containing polyacrylic resin clear paint (manufactured by Kansai Paint), and is a square container having an outer size of 4 mm × 3 mm and a height of 44 mm. The inside was filled with a glass fiber having a porosity of 85% as a liquid retaining material 14.

  The rectangular tube was provided with airtightness by bonding acrylic plate lids 12 and 13 each having a thickness of 2 mm on both the upper and lower sides.

  A porous layer 8 having a width of 36 mm and a through hole having a diameter of about 1 mm and an opening ratio of about 70% is provided on the outer peripheral surface of the rectangular cylinder. A fuel outlet 9 and a supply port 10 having a diameter of 3 mm and an inner diameter of 2 mm are provided.

The porous layer 8 of the rectangular tube is covered with a stainless steel SUS316 mesh serving as the anode current collecting plate 6, and a platinum / ruthenium-supported carbon catalyst is dried thereon by a weight of 37 mm to cover the porous portion 8 of the rectangular tube with a width of 37 mm. A 5% by weight aqueous Nafion 117 alcohol solution (water, isopropanol, normal propanol in a weight ratio of 20:40:
A mixed solvent of No. 40: manufactured by Fluke Chemical Co.) was added and kneaded into a paste, and the mixture was applied at 60 ° C. for 3 hours so as to have a thickness of 30 μm when dried, thereby forming an anode 3.

After drying at about 60 ° C. for 3 hours, the amount of platinum was about 2 mg / cm ² and the amount of ruthenium was about 1 mg / cm ² .

Then, after drying at 60 ° C., 5% by weight of Nafion 117 alcohol aqueous solution is evaporated, and a liquid concentrated to about 30% by weight is applied to the entire outer periphery of the rectangular tube so that the electrode portion has a coating thickness of about 50 μm, and the electrolyte membrane is formed. 2 was formed.

  After drying at room temperature for 10 hours and further drying at 60 ° C. for 3 hours and measuring the coating thickness of the non-electrode portion, the corner portion of the rectangular tube was slightly thicker, but it was in the range of 73 to 76 μm in the flat portion. In this case, the electrolyte film thickness is generally about 45 μm.

A 5% by weight aqueous solution of Nafion 117 alcohol, which is equivalent to 60% by weight of Nafion 117 in terms of dry weight, was added to the platinum-supported carbon powder catalyst on the formed electrolyte membrane 2 and kneaded in a paste form. The coating was applied so as to overlap with the anode 3 so as to have a thickness of 15 μm, and dried at 60 ° C. for 3 hours to form a cathode 4. The cathode platinum amount at this time is about 0.8
mg / cm ² .

  Next, an aqueous dispersion of water repellent polytetrafluoroethylene fine particles (Teflon (registered trademark) Dispersion D-1: manufactured by Daikin Industries) is added to the carbon powder so that the weight after firing is 40 wt%, and the mixture is kneaded. Then, the paste was applied to one side of a carbon fiber non-woven fabric having a thickness of about 100 μm and a porosity of 87% so as to have a thickness of about 20 μm, dried at room temperature, and then fired at 270 ° C. for 3 hours to diffuse. Layer 5 was formed.

The obtained diffusion layer 5 was cut out into a tape shape having the same width as the cathode width of the above-mentioned square cylinder type fuel cell, and this was wound on the cathode of the square cylinder type fuel cell so that the seam did not overlap, and a stainless steel SUS316 mesh was collected. The diffusion layer 5 was fixed as the electric body 7. The terminals of the fuel cell unit were connected to the ends of the anode and cathode current collector plates 6,7.

The prismatic fuel cell unit thus obtained is a unit cell having a fuel filling volume of about 0.26 cm ³ and a power generation effective area of about 5 cm ² , and is a unit at 55 ° C. measured by filling a 10 wt% methanol aqueous solution as a liquid fuel. The current / voltage characteristics of the initial characteristics of the battery showed an output voltage of 0.30 V at a load current density of 150 mA / cm ² as shown by a curve 61 in FIG. When a power supply is configured by mounting a plurality of fuel cell units having such a structure, the fuel cell units can be arranged and mounted compactly only by providing a necessary and sufficient space for air diffusion.

  Next, a second embodiment of the present invention will be described below.

  FIG. 7A shows an external structure of a cylindrical fuel cell unit using a methanol aqueous solution as a fuel according to another embodiment of the present invention, and FIG. 7B shows a cross-sectional configuration thereof.

  A hollow cylinder made of polypropylene, 4.5 mm in outer diameter, 3.6 mm in inner diameter, and 44 mm in length. A copper anode terminal plate 15 having a width of 3 mm and a thickness of 0.2 mm is fitted on one end of the cylinder in advance. The anode current collector plate 6 was formed by applying a conductive carbon coating material having polyvinylidene fluoride as a binder to a thickness of about 50 μm on the outer periphery of the mold support 1. A porous layer 8 having a diameter of about 0.5 mm was provided on the 38 mm wide cylindrical wall surface to which the anode current collector 6 was applied so as to have an opening ratio of about 65%.

The cylinder is filled with glass fiber having a porosity of 85% as a liquid retaining material 14, and the upper and lower portions of the cylinder are made of polypropylene and have a thickness of 2 mm having a fuel outlet 9 and a supply port 10 having an outer diameter of 3 mm and an inner diameter of 2 mm. The lids 12 and 13 were welded to make them airtight. Next, a 5 wt% aqueous Nafion 117 alcohol solution, in which Nafion is equivalent to 60 wt% of the catalytic amount by dry weight, was added to the platinum-ruthenium-supported carbon catalyst, and the mixture was kneaded into a paste and dried at 60 ° C. for 3 hours. An anode 3 was formed by applying a screen printing method to a 38 mm × 12 mm in-plane of a Nafion 117 (manufactured by DuPont) electrolyte membrane 2 having a size of 44 mm × 14 mm and a thickness of 50 μm so as to have a thickness of 25 μm. The amount of platinum was dried 3 hours at about 60 ° C. is about 1.3 mg / cm ^2, the amount of ruthenium was about 0.65 mg / cm ^2.

  Next, a 5 wt% aqueous Nafion 117 alcohol solution, in which Nafion is equivalent to 60 wt% of the catalytic amount by dry weight, is added to the platinum-supported carbon powder catalyst, and the mixture is kneaded in a paste form so that the dry thickness becomes 15 μm. The surface of the electrolyte membrane 2 opposite to the surface coated with the anode 3 is coated by a screen printing method so as to overlap with the anode 3 and dried at 60 ° C. for 3 hours to form a cathode 4 to form an electrolyte membrane / electrode assembly. And

At this time, the amount of cathode platinum was about 0.8 mg / cm ² . Next, an aqueous dispersion of the water repellent polytetrafluoroethylene fine particles is added to the carbon powder so that the weight after firing becomes 40 wt%, and the mixture is kneaded to form a paste-like material having a thickness of about 100 μm. It is applied to one side of a carbon fiber nonwoven fabric having a rate of 87% so as to have a thickness of about 20 μm, dried at room temperature, and baked at 270 ° C. for 3 hours to form a diffusion layer 5.

  A silicone liquid gasket 16 is applied to a part width of about 2.5 mm where the electrolyte membrane on the upper and lower outer circumferences of the electrolyte membrane / electrode assembly is exposed, and wound around the porous portion 8 of the cylindrical hollow support 1. 5% by weight of Nafion 117 alcohol aqueous solution to about 30% by weight in advance at the electrolyte membrane joint exposed in the longitudinal direction of the cylindrical support 1 of the electrolyte membrane / electrode assembly while fastening the upper and lower ends and tightening from the outer periphery. The concentrated liquid is applied and dried at 60 ° C. for about 3 hours to bind.

  The prepared diffusion layer 5 was cut into a tape shape having the same width as the cathode, wound around the cathode of the cylindrical fuel cell so that the seams did not overlap, and coated on a copper mesh with a conductive carbon paint using polyvinylidene fluoride as a binder. The mesh was used as a cathode terminal.

In addition, the seals at both ends of the cylindrical fuel cell unit were fastened and fixed by rubber-based fastening bands 17. The obtained cylindrical fuel cell unit is a single cell having a fuel filling volume of about 0.37 cm ³ and an effective power generation area of about 4.5 cm ² , and is a unit cell at 55 ° C. measured by filling a 10 wt% methanol aqueous solution as a liquid fuel. The initial current / voltage characteristics indicated an output voltage of 0.32 V at a load current density of 150 mA / cm ² as shown by a curve 62 in FIG.

  When the fuel cell unit is cylindrical as in this embodiment, the process of joining the cell members to the outer periphery of the hollow support becomes easy, the tightening by the porous cathode current collector 7 becomes uniform, and the output voltage of the unit cell becomes higher. Can be higher.

  A third embodiment of the present invention will be described below.

  FIG. 8A shows the external structure of a high-voltage cylindrical fuel cell unit using a methanol aqueous solution as a fuel according to another embodiment of the present invention, and FIG. I do.

  A hollow cylinder made of polypropylene having an outer diameter of 6.4 mm, an inner diameter of 5.5 mm, a length of 90 mm, and two ribs 21 of 1.5 mm in width and 50 μm in height at the outer periphery 30 mm from both ends is manufactured. A copper anode terminal plate 15 having a width of 3 mm and a thickness of 0.2 mm is fitted on the outer periphery of the upper cylindrical end cut into a width of 3 mm and an outer diameter of 6.0 mm to form a hollow cylindrical support 1. . A mask is applied with a resin tape to the outer peripheral surface except the rib surface and the anode current collector plate 6 at the end of the support, and a conductive carbon paint using polyvinylidene fluoride as a binder is applied to a thickness of about 50 μm on the remaining outer peripheral surface. Thus, the anode current collector 6 connected to the interconnector 11 was formed. Three current collector plate forming portions having a width of 25 mm in contact with one side surface of the rib were provided with through holes having a diameter of approximately 0.5 mm so as to have an opening ratio of approximately 65%, thereby forming a porous portion 8. An anode 3 having a thickness of 30 μm is applied to the three divided current collector surfaces in the same manner as in the first embodiment. Then, the rib portion 21 and the anode current collector of the interconnector 11 are masked, and the current collector is formed on the anode 3 formed on the current collector and on the unmasked portion of the anode current collector in the same manner as in the first embodiment. The electrolyte membrane 2 is formed so as to have a thickness of about 40 μm.

  Next, a cathode 4 having a thickness of 15 μm is formed on the electrolyte membrane 2 at a position overlapping with the anode 3 in the same manner as in the first embodiment, and is used in the diffusion layer 5 manufactured in the same manner as in the first embodiment. The same cathode current collector 7 as above was overlapped and the outer peripheral portion was fixed with a polyethylene fastening mesh 20.

  Next, the mask of the anode current collector is removed and the cathode 4 and the side surface of the diffusion layer 5 are masked. The anode current collector is filled with a conductive paint containing nickel metal powder as a filler and polyvinylidene fluoride as a binder. It is electrically coupled to the side surface of the diffusion layer 5.

A glass fiber having a porosity of 85% is filled as a liquid retaining material 14 in the cylinder of the obtained cylindrical fuel cell unit, and a fuel outlet 9 and a supply port, which are made of polypropylene and have an outer diameter of 3 mm and an inner diameter of 2 mm, are provided above and below the cylinder. The lids 12 and 13 having a thickness of 2 mm and having a thickness of 10 were welded to provide airtightness. The anode terminal 18 was pulled out from the anode terminal plate 15, and the cathode terminal 19 was drawn out from the lower end of the cathode current collector 7. The obtained cylindrical fuel cell unit having three cells in series is a unit cell having a fuel filling volume of about 1.8 cm ³ and an effective power generation area of about 5 cm ² , and has a temperature of 55 ° C. when a 10 wt% methanol aqueous solution is charged as a liquid fuel. The voltage at a load current of 0.8 A was about 0.98 V, as shown by curve 71 in FIG.

  In the cylindrical fuel cell unit having such a structure, the joining process of the battery members is facilitated, the output voltage of the unit cell can be increased, and the output voltage of the fuel cell unit can be increased. This gives you the freedom to choose the height of the power supply. Particularly, when the load current is relatively small and a high voltage is required, the power supply can be made compact.

  Next, a fourth embodiment of the present invention will be described.

  FIG. 9 (a) shows the external structure of a square-tube, high-voltage type fuel cell unit using a methanol aqueous solution as a fuel according to another embodiment of the present invention, before the polyethylene mesh 20 tightened from the outer periphery is attached. FIG. 9B shows the external structure, FIG. 10A shows one cross-sectional configuration of the support 1, and FIG. 10B shows another cross-sectional configuration adjacent thereto.

  As shown in FIG. 9B, the hollow support 1 of the fuel cell unit is formed of a polypropylene square tube having an outer shape of 10 mm × 10 mm × 115 mm and a thickness of 1 mm. On the four outer surfaces of the square tube, a 9 mm × 104 mm, 200 μm deep engraved structure battery mounting portion was provided, and as shown in FIGS. An anode current collector plate 6 was formed by applying a conductive carbon paint having a thickness of about 50 μm using vinylidene as a binder.

  Next, a porous portion 8 is provided with a through hole having a diameter of about 0.5 mm and an opening ratio of about 65%, with a region of 5 mm × 100 mm in the surface of the battery mounting portion as a current-carrying portion. The inside of the square tube is filled with glass fiber having a porosity of 85% as a liquid retaining material 14, and the upper and lower sides of the tube are made of polypropylene having an outer diameter of 5 mm and an inner diameter of 4 mm, and glass fiber having an porosity of 85% inside. The lids 12 and 13 each having a thickness of 2 mm and having the fuel discharge port 9 and the supply port 10 filled as the liquid material 14 were adhered to provide airtightness.

  In the same manner as in Example 2, the size of the electrolyte membrane 2 was determined using a platinum-ruthenium-supported carbon catalyst as the anode catalyst, a platinum-supported carbon powder catalyst as the cathode catalyst, a Nafion membrane 117 (manufactured by DuPont) with a thickness of 50 μm as the electrolyte membrane. An anode 3 having a size of 5 mm × 100 mm, a thickness of 25 μm, and a cathode 4 having a thickness of 15 μm were superposed on both sides of the anode 3 to form an electrolyte membrane / electrode assembly.

  Next, the peripheral electrolyte membrane of the electrode / electrolyte membrane assembly and the battery mounting portion are bonded with the silicone-based liquid gasket 16 such that the anode side of the electrode / electrolyte membrane assembly contacts the battery mounting portion of the hollow support. The same diffusion layer 5 as used in Example 2 and a cathode current collector 7a having a tab 7b at the end manufactured by the same method as used in Example 2 are superimposed on the mounted cathode surface. At the same time, the outer peripheral portion was fixed to the electrolyte membrane 2 with a fastening mesh 20 made of polyethylene via a silicone-based liquid gasket 16.

  As shown in FIG. 10B, the tab portions of the cathode current collectors 7 mounted on the four surfaces of the hollow support are alternately overlapped in the upside-down direction, and each tab is adjacent to the adjacent anode current collector 7. To form a battery group of four series.

The obtained cylindrical fuel cell unit has an effective power generation area of about 5 cm ² , and the performance when a 10 wt% methanol aqueous solution is used as the liquid fuel is as follows. At 5 A, a performance of 1.3 V was exhibited. Such a structure of the prismatic fuel cell unit makes it easy to join the battery members because each surface of the prismatic cylinder independently constitutes the battery, and can increase the output voltage of the unit cell. Since the output voltage of the fuel cell unit can be increased, the degree of freedom in selecting the height of the power source comes up. Particularly, when the load current is relatively small and a high voltage is required, the power supply can be made compact.

  Here, as Comparative Example 1, one in-plane structure and a longitudinal cross section of a separator structure based on a conventional structure are shown in FIG. 12A, and the other in-plane structure and a cross section are shown in FIG. FIG. 13 shows the stacking configuration, FIG. 14 shows the configuration of the cell holder, and FIG. 15 shows a power supply system structure in which the cells are stacked in series and a fuel tank is attached.

  As the separator, a graphitized carbon plate having a size of 50 mm × 21 mm and a thickness of 3 mm was used. At the bottom of the separator 81, an internal manifold 82 of 5 mm × 15 mm is provided. As shown in FIG. 12A, grooves of 1 mm width × 0.8 mm depth × 39 mm length are formed at a pitch of 2 mm, and the rib portions 21 are formed. A fuel supply groove was formed to connect the manifold 82 and the upper side surface of the separator 81. As shown in FIG. 12 (b), a rib 21 having grooves of 1 mm width × 1.4 mm depth × 21 mm length formed at a pitch of 2 mm is formed on the other surface in a direction perpendicular thereto. An oxidant supply groove connecting the side surfaces of. Next, a manifold opening 86 was provided in Nafion 117 having a size of 50 mm × 21 mm and a thickness of 50 μm as an electrolyte membrane, and an anode having a size of a power generation unit of 36 mm × 14 mm and a thickness of 25 μm was formed on one surface in the same manner as in Example 2. Then, an electrolyte / membrane assembly 91 in which a cathode having a thickness of 15 μm was applied to the other surface was produced.

As the anode catalyst, a platinum-ruthenium alloy catalyst supported on a carbon carrier was used, and as the cathode catalyst, platinum supported on a carbon carrier was used. The amount of platinum in the anode is about 1.3 mg /
cm ² , the amount of ruthenium was about 0.65 mg / cm ² , and the amount of platinum in the cathode was about 0.8 mg / cm ² .

  Then, a 250 μm-thick liner 92 made of polyethylene terephthalate and a 400 μm-thick neoprene gasket 16 having the same size as the separator 81 and provided with the manifold opening 86 and the power generation opening 85 were produced. Further, a diffusion layer 5 was produced in the same manner as in Example 1.

Next, a pulp paper made wicking material 94 composed of the fuel electrode side groove embedding portion 88 and the manifold embedding portion 87 of the separator 81 was produced. As shown in FIG. 21, these components are stacked in 14 layers in the order of separator 81, wicking material 94, liner 92, gasket 93, electrolyte membrane / electrode assembly 91, diffusion layer 5, liner 92, and separator 81. And pressurized at about 5 kg / cm ² to obtain a laminated battery 23. This laminated battery 23 was fastened and fixed with a fastening band 17 made of fluoro rubber (Viton; manufactured by Du Pont) via a SUS316 cell holder 105 having a structure shown in FIG. 14 as shown in FIG. 15A. . The fuel tank 102 was made of polypropylene having a size of 50 mm in height × 21 mm in length × 21 mm in width and 0.3 mm in side wall thickness.

  As shown in FIG. 15 (b), a screw cap type fuel supply port 103 having a gas selective permeation function equipped with a porous polytetrafluoroethylene membrane having a structure shown in FIG. And the inside of the fuel tank is filled with an aqueous methanol solution as the fuel 104.

The manufactured laminated battery was connected to the fuel tank 102 in a structure as shown in FIG. 15B, and a power supply having a structure as shown in FIG. 15A was manufactured. The obtained power source has a fuel tank having a size of about 50 mm height × 72 mm length × 21 mm width, a power generation unit area of about 5 cm ² and a capacity of about 20 cm ³ .

  It shows a voltage of 2.5 V when the operating temperature is 60 ° C. and the load current is 0.8 A, and the voltage when power is generated by blowing a fan over the entire opening of the side wall of the power supply formed by the air electrode side groove of the separator is 4 .1V.

  It is considered that this is because the supply of oxygen due to sufficient diffusion of air is insufficient in the air electrode side groove structure of the separator at the time of power supply load. The volume output density of this power supply was about 26 W / l without using a ventilation fan, and was about 43 W / l when using a ventilation fan. The fuel tank was filled with 19 ml of a 10 wt% methanol aqueous solution, and was operated at an operating temperature of 60 ° C. and a load current of 0.8 A using a blower fan. When the output voltage was maintained at 4.0 V for about 25 minutes, the voltage rapidly decreased. . Therefore, the volume energy density of one 10 wt% methanol aqueous solution fuel was 18 Wh / l when a ventilation fan was used.

  Next, as a comparative example 2, a high-voltage power supply structure using a separator will be described with reference to FIG. 17 and a structure of a cell holder will be described with reference to FIG.

  The separator, wicking material, liner, gasket, membrane / electrode assembly, and diffusion layer, which are the components of the battery, are the same materials and have the same size as in Comparative Example 1, and the unit procedure is set to 21 cells in the same procedure. Two sets of stacked batteries 23 were produced.

  These two sets of laminated batteries were inserted into the battery fixing plate 106 of the cell holder 105 shown in FIG. 16 so that the bottom surfaces of the batteries were in contact with each other, and were fixed with the fastening band 17 made of fluorine-based rubber as in Comparative Example 1. The fuel tank 102 is made of polypropylene and has a size of 50 mm in height × 21 mm in length × 35 mm in width and 0.3 mm in side wall thickness.

  As shown in FIG. 17, a screw-cap type fuel supply port 103 having a gas selective permeation function equipped with a porous polytetrafluoroethylene membrane having a structure shown in FIG. Have. As shown in FIG. 17, the produced stacked battery was connected to a fuel tank by the same mechanism as in Comparative Example 1, and two sets of stacked batteries were connected in series to constitute a power supply.

The obtained power supply has a size of about 110 mm height × 110 mm length × 21 mm width, and has two fuel tanks 102 each having a unit cell power generation unit area of about 5 cm ² and a capacity of about 34 cm ³ . It shows a voltage of 7.4 V when the operating temperature is 60 ° C. and the load current is 0.8 A, and the voltage when power is generated by blowing a fan over the entire opening of the side wall of the power supply formed by the air electrode side groove of the separator is 13 .1V. It is considered that this is because the supply of oxygen due to sufficient diffusion of air is insufficient in the air electrode side groove structure of the separator at the time of power supply load.

The volume output density of this power supply was about 23 W / l without a ventilation fan and about 41 W / l when a ventilation fan was used. The two fuel tanks were filled with a 10 wt% aqueous methanol solution in a total of 150 cm ³ , and were operated at an operating temperature of 60 ° C. and a load current of 0.8 A using a blower fan. Dropped rapidly. Therefore 10
The volume energy density per filling of the wt% methanol aqueous solution fuel was 20 Wh / l when a ventilation fan was used.

  Hereinafter, a fifth embodiment of the present invention will be described. As a power supply system composed of a prismatic methanol fuel cell unit according to an embodiment of the present invention, a power supply structure produced by the method of Embodiment 1 and combining 14 fuel cell units filled with a liquid retaining material 14 in series is provided. A cross-sectional configuration illustrated in FIG. 18A and illustrating the connection with the fuel tank will be described with reference to FIG.

  The fuel cell units 101 are housed in series in 14 cells made of polyethylene having the structure shown in FIG. The fuel tank 102 is made of polypropylene and has a size of 50 mm in height, 72 mm in length and 15 mm in width, and has a side wall thickness of 0.3 mm.

As shown in FIG. 12 (b), the upper and lower sides of the side wall and the fuel supply port 10 and the discharge port 9 of the fuel cell unit 101 are hermetically mounted using the fuel tank 102 as a platform. A fuel supply port 103 of a screw cap type having a gas selective permeation function equipped with a porous polytetrafluoroethylene membrane having a structured structure is provided, and a 10 wt% methanol aqueous solution is filled as a fuel 104 in a fuel tank.

The cathode terminal of the fuel cell unit mounted on the cell holder 105 is connected to an adjacent anode terminal, and both ends connected in series 14 are power terminals. The obtained power supply has a fuel tank of approximately 50 mm height × 72 mm length × 20 mm width and a capacity of about 50 cm ³ , and exhibits a voltage of 4.2 V at an operating temperature of 65 ° C. and a load current of 0.8 A. Was. The volume power density of this power supply was about 47 W / l. The fuel tank was filled with 50 cm ³ of a 10 wt% methanol aqueous solution and operated at an operating temperature of 60 ° C. and a load current of 0.8 A. As a result, power generation could be stably continued at an output voltage of about 4.2 V for about 60 minutes. Therefore, the volume energy density of one 10 wt% methanol aqueous solution fuel was 47 Wh / l.

  According to the present embodiment, 14 fuel cell units can be compactly mounted, so that the capacity of the fuel tank is larger than that of Comparative Example 1 which has almost the same volume output density in the battery structure using the conventional separator. And the volumetric energy density was about 2.5 times. Since each fuel cell unit is mounted at an interval where air as an oxidant can sufficiently diffuse, it was possible to generate power without using a fan for assisting air supply unlike the power supply of Comparative Example 1. .

  Next, a sixth embodiment of the present invention will be described. As a power supply system composed of a cylindrical fuel cell unit using methanol fuel according to another embodiment of the present invention, a power supply structure obtained by combining 14 series and 2 parallel fuel cell units manufactured by the method of the second embodiment will be described. FIG. 20A shows a cross-sectional configuration for explaining the connection with the fuel tank shown in FIG.

The fuel cell unit 101 is accommodated in a cell holder 105 having a structure shown in FIG. The fuel tank 102 has a platform structure made of polypropylene and having a size of 70 mm in height × 76 mm in length × 22 mm in width and a side wall thickness of 0.3 mm. As shown in FIG. 20 (b), the platform of the fuel tank 102 is filled with a liquid retaining material 14, and the upper surface of the tank is provided with a porous polytetrafluoroethylene membrane having a structure shown in FIG. A fuel supply port 103 of a screw cap type having a permeation function is provided, and the inside is filled with an aqueous methanol solution as fuel.

  As shown in FIG. 20B, the fuel supply port 10 of each fuel cell unit 101 is airtightly connected to a fuel tank 102 serving as a platform, and the upper part of the fuel cell unit group is made of polypropylene and has an outer shape of 10 mm high. An exhaust tank 110 having a size of 76 mm x 76 mm length x 8 mm width and a side wall thickness of 0.3 mm is hermetically mounted to the outlet 9 of each fuel cell unit. The upper surface of the exhaust tank 110 is provided with an exhaust port 111 which is a screw lid type gas selective transmission port equipped with a porous polytetrafluoroethylene film similar to that shown in FIG.

The cathode terminal of each fuel cell unit housed in the cell holder 105 is connected to an adjacent anode terminal and electrically connected in 14 series and 2 parallel. The obtained power supply has a fuel tank of approximately 70 mm height × 76 mm length × 22 mm width and a capacity of about 55 cm ³ , and exhibits a voltage of 3.6 V at an operating temperature of 60 ° C. and a load current of 1.5 A. Was. The volume power density of this power supply was about 50 W / l.

A fuel tank was filled with 55 cm ³ of a 10 wt% methanol aqueous solution and operated at an operating temperature of 60 ° C. and a load current of 1.5 A. As a result, power generation was continued at an output voltage of about 3.5 V for about 20 minutes.

  According to the present embodiment, 28 fuel cell units can be compactly mounted, so that the power generation area can be increased and a large load current can be changed as compared with the battery structure of Comparative Example 1 using the conventional separator. In addition, since each fuel cell unit is mounted at an interval where air as an oxidant can sufficiently diffuse, power is generated without using a fan for assisting air supply as in the power supplies of Comparative Examples 1 and 2. It was possible.

Hereinafter, a seventh embodiment of the present invention will be described. As a power supply system composed of a fuel cell unit using a cylindrical high-voltage type methanol aqueous solution fuel according to another embodiment of the present invention, a power supply in which 14 fuel cell units manufactured by the method of Embodiment 3 are combined in series FIG. 22 (a) shows the external structure of FIG. 22, and FIG. 22 (b) shows the cross-sectional structure of the connection with a fuel tank serving as a platform.

Fourteen fuel cell units 101 are mounted on a cell holder 105 made of polyethylene having the same structure as that described in the fifth embodiment and made of polyethylene, and are electrically connected in series. The fuel tank 102 serving as a platform has an outer shape of 100 mm in height × 120 mm in length × 13 mm in width, and has a side wall thickness of 0.3 mm. On the upper surface of the fuel tank 102, there is provided a screw cap type fuel supply port 103 having a gas selective permeation function equipped with a porous polytetrafluoroethylene membrane having a structure shown in FIG. Is filling. As shown in FIG. 22B, the side wall of the fuel tank 102 is hermetically mounted via a fuel supply port 10 and a discharge port 9 of the fuel cell unit. The obtained power source has a fuel tank of approximately 100 mm height × 120 mm length × 21 mm width and a capacity of about 145 cm ³ , and exhibits a voltage of 13.3 V at an operating temperature of 60 ° C. and a load current of 0.8 A. Was. The volume power density of this power supply was about 42 W / l. When the fuel tank was filled with 145 cm ³ of a 10 wt% methanol aqueous solution and operated at an operating temperature of 60 ° C. and a load current of 0.8 A, power generation could be stably continued at an output voltage of about 13.2 V for about 65 minutes. Accordingly, the volume energy density of one 10 wt% methanol aqueous solution fuel was 45 Wh / l.

  According to the present embodiment, since 14 fuel cell units can be compactly mounted, the capacity of the fuel tank is increased as compared with Comparative Example 2 in which a power supply having substantially the same size is manufactured with a battery structure using a conventional separator. And the volumetric energy density was approximately doubled. Since each fuel cell unit was installed at an interval where air as an oxidant could sufficiently diffuse, it was possible to generate power without using a fan for assisting air supply unlike the power supply of Comparative Example 2. .

  Hereinafter, a fuel cell unit manufactured by the method of Embodiment 4 will be described as a power supply system including a fuel cell unit using an aqueous methanol solution of a square cylinder type and a high voltage type as a fuel according to an eighth embodiment of the present invention. FIG. 23A shows an external structure of a power supply which is combined in seven series, and FIG. 23B shows a cross-sectional configuration showing connection with a fuel tank serving as a platform.

  The seven fuel cell units 101 are mounted on a polyethylene gas permeable cell holder 105 having the same structure as that described in the fifth embodiment, and are electrically connected in series. The fuel tank 102 is made of polypropylene having an outer shape of 130 mm in height × 80 length × 22 mm in width and 1 mm in thickness, and has a structure having a platform for mounting a battery. As shown in FIG. 23 (b), the platform of the fuel tank 102 is filled with the liquid retaining material 14, and the gas selective permeation function in which a porous polytetrafluoroethylene membrane having the structure shown in FIG. The fuel supply port 103 is provided with a screw cap type and has a methanol aqueous solution filled therein as fuel. The platform of each fuel cell unit 101 and the fuel tank 102 is airtightly connected via the fuel supply port 10 of the fuel cell unit 101 with the same mechanism as in the sixth embodiment. At the top of the fuel cell unit group, an exhaust tank 110 made of polypropylene and having a size of 10 mm height × 80 mm length × 10 mm width and a side wall thickness of 0.3 mm passes through the fuel outlet 9 of each fuel cell unit 101. And is mounted airtight.

On the upper surface of the exhaust tank 110, there is provided an exhaust port 111 which is a screw lid type gas selective transmission port equipped with the porous polytetrafluoroethylene film shown in FIG. The power supply obtained is approximately 130
It has a fuel tank of about 110 cm ^{3 in} size with a size of mm height × 80 mm length × 22 mm width, and showed a voltage of 8.5 V at a load current of 0.8 A at an operating temperature of 60 ° C. The volume power density of this power supply was about 30 W / l. The fuel tank was filled with 110 cm ³ of a 10 wt% methanol aqueous solution and operated at an operating temperature of 60 ° C. and a load current of 0.8 A. As a result, power generation could be stably continued at an output voltage of about 8.5 V for about 75 minutes.

  Therefore, the volume energy density of one 10 wt% methanol aqueous solution fuel was 37 Wh / l. According to the present embodiment, since seven fuel cell units in which four cells are connected in series can be compactly mounted, the capacity of the fuel tank can be reduced as compared with a case where a power source is manufactured using a battery structure using a conventional separator. The volume energy density was about twice as large. Since each fuel cell unit is mounted at an interval where air as an oxidant can sufficiently diffuse, power generation can be performed without using a fan for assisting air supply as in the power supplies of Comparative Examples 1 and 2. It was possible.

  FIG. 24A shows an external structure of a fuel cell unit as a power supply system composed of a cylindrical fuel cell unit using a methanol aqueous solution as a fuel according to a ninth embodiment of the present invention, and FIG. The cross-sectional configuration will be described.

A hollow cylindrical support 1 made of stainless steel SUS316 and having a closed bottom with an outer diameter of 5.6 mm, an inner diameter of 5.3 mm, and a length of 47 mm and provided with a screw-type connector 24 in the upper 5 mm. A porous portion 8 having a through hole having a diameter of about 0.5 mm over a width of 36 mm was provided on the outer wall of the cylinder so that the opening ratio was about 70%. On the other hand, a 17.5 mm × 42 mm Nafion 117 membrane was used as the electrolyte membrane 2, and a platinum / ruthenium catalyst with a carbon carrier was applied to a 16 mm ×
It is coated on one of the electrolyte membrane surfaces so as to have a size of 36 mm and a thickness of 20 μm to form an electrode of the anode 3, and a platinum catalyst with a carbon carrier is provided on the opposite surface corresponding to the anode application portion by 60% of the weight of this catalyst. The polytetrafluoroethylene powder was added as a water repellent and mixed, and the mixture was applied so as to have a size of 16 mm × 36 mm and a thickness of 15 μm to prepare an electrolyte membrane / electrode assembly as the cathode electrode 4. A silicone liquid gasket 16 is applied to a 3 mm wide portion of the electrolyte membrane exposed at both ends of the long side of the obtained electrolyte membrane / electrode assembly, and the cathode surface overlaps the porous portion 8 of the hollow support 1. The electrolyte membrane 2 exposed at both ends of the short side portion while being wound and tightened from the outer peripheral portion is preliminarily formed at a joint portion in contact with the cylindrical support in the longitudinal direction.
A Nafion alcohol solution concentrated to wt% was applied, dried and joined.

The exposed surfaces of the electrolyte membrane 2 corresponding to the gasket 16 application portions at the upper and lower ends of the electrolyte membrane / electrode assembly mounted on the hollow cylindrical support are fixed with rubber-based fastening bands 17, and the outer peripheral surface of the cathode 4 is made of copper. The porous cathode current collector 7 covered with a conductive carbon paint using polyvinylidene fluoride as a binder was fastened and fixed to the mesh. The fixed cathode current collector 17 was used as a cathode terminal, and a metal hollow cylindrical support was used as an anode terminal. The resulting fuel cell unit had a power generation area of about 5.7 cm ² and a hollow cylinder volume of about 0.8 cm ³ . A hollow cylinder was filled with a 10 wt% methanol aqueous solution, and the performance of the fuel cell unit was evaluated at a temperature of about 60 ° C. As a result, the load voltage was 0.8 A and the output voltage was 0.36 V.

  Since the fuel cell unit according to the present embodiment is composed of a single cell, the hollow support can be composed of a corrosion-resistant metal material. Accordingly, the hollow support has the functions of an anode current collector and an anode terminal, and the configuration of the fuel cell unit can be simplified.

FIG. 25A shows the external structure of a power supply in which 42 cylindrical fuel cell units manufactured in this example are connected in series, and FIG. 25A shows a cross-sectional structure showing connection with a fuel tank serving as a platform.
The power supply configuration shown in FIG. The fuel tank 102 is made of vinyl chloride and has a height of 65 mm ×
The outer dimensions were 43 mm width x 50 mm length, the bottom thickness was 5 mm, and the other wall thickness was 1 mm. On the upper surface of the fuel tank are provided two screw cap type fuel supply ports 103 having a gas selective permeation function equipped with a porous polytetrafluoroethylene membrane having a structure shown in FIG. Is filled. A screw-type mounting port is provided on the bottom surface of the fuel tank 102 and is air-tightly connected to the connector 24 of the fuel cell unit 101.

The power source is a group of fuel cell units 101 mounted on the fuel tank 102 and the outer dimensions are 43 mm width x
A substrate 112 having a length of 50 mm and a thickness of 3 mm was fixed by a support 113. The obtained power source is approximately 111 mm high x 43 mm wide x 50 mm long, and the maximum fuel filling volume is about 150 mm.
cm ³ , power generation area 5.7 cm ² , 42 in series. This power supply was filled with 150 cm ³ of a 10 wt% methanol aqueous solution as a fuel and operated at a temperature of about 60 ° C. and a load current of 1 A, and continued to generate power at an output voltage of about 13 V for 50 minutes. Therefore, the volume output density of this power source was 54 W / l, and the volume energy density per charge of one 10 wt% methanol aqueous solution fuel was 45 Wh / l.

  Since this power supply has a fuel tank in the upper part, the fuel is always filled in the fuel cell unit cylinder, so that it is not necessary to fill the liquid retaining material of the fuel as shown in Examples 5 to 6. Has features. Also, in this example, the volume energy density was about twice or more as compared with the battery of Comparative Example 2. Since each fuel cell unit is mounted at an interval where air as an oxidant can sufficiently diffuse, power generation can be performed without using a fan for assisting air supply as in the power supplies of Comparative Examples 1 and 2. It was possible.

  Next, FIG. 26A shows a power supply system composed of a cylindrical fuel cell unit using an aqueous methanol solution as a fuel according to a tenth embodiment of the present invention, and FIG. FIG. 27 shows a cross section in which the fuel tank and the auxiliary fuel tank are joined.

The fuel cell unit 101 is accommodated in a cell holder 105 having a structure shown in FIG. The fuel tank 102 has a size of 20 mm in height × 76 mm in length × 30 mm in width and has a side wall thickness of 1 mm made of polypropylene. As shown in FIG. 26 (b), the platform of the fuel tank 102 is filled with a liquid retaining material 14, and the platform portion of the auxiliary fuel tank 107 is provided with a detachable connector 24 as shown in FIG. Have. The auxiliary fuel tank 107 is made of polypropylene and has a 49 mm height × 76 mm length × 22 mm width, side wall thickness of 1 mm, and a porous polytetrafluoroethylene film having the structure shown in FIG. The fuel supply port 103 is provided with a screw lid type having a gas selective permeation function, and is filled with a methanol aqueous solution as fuel.

As shown in FIG. 26 (b), the fuel supply port 10 of each fuel cell unit 101 is air-tightly connected to a fuel tank 102 serving as a platform, and the upper part of the fuel cell unit group is made of polypropylene and has a height of 10 mm. An exhaust tank 110 having a size of 76 mm x 76 mm length x 8 mm width and a side wall thickness of 0.3 mm is hermetically mounted to the outlet 9 of each fuel cell unit. The upper surface of the exhaust tank 110 is provided with an exhaust port 111 which is a screw lid type gas selective transmission port equipped with a porous polytetrafluoroethylene film similar to that shown in FIG. The cathode terminal of each fuel cell unit housed in the cell holder 105 is connected to an adjacent anode terminal and is electrically connected in 28 series. The obtained power source had a size of about 70 mm height × 76 mm length × 30 mm width and was equipped with a fuel tank having a capacity of about 31 cm ³ , and the capacity of the auxiliary fuel tank was about 69 cm ³ . A power generation test at an operating temperature of 60 ° C. showed a voltage of 8.4 V at a load current of 0.8 A. When the auxiliary fuel tank 107 was filled with 65 cm ³ of a 10 wt% methanol aqueous solution and operated at an operating temperature of 60 ° C. and a load current of 1.5 A, power generation was continued at an output voltage of about 3.6 V for about 80 minutes. After this, the auxiliary fuel tank filled with 65 cm ^{3 of} 10 wt% methanol aqueous solution was newly replaced and the power was generated. When the power was operated at an operating temperature of 60 ° C. and a load current of 1.5 A, the output voltage was about 3.6 V and could be continued for about 80 minutes. Was. In the direct methanol fuel cell, an aqueous methanol solution is used as a fuel. In addition to the amount of fuel consumed in power generation, the fuel is permeated through the electrolyte membrane and consumed.

  Since the ratio of the permeation amount of methanol and water permeates the electrolyte membrane depending on the operation state, it is necessary to adjust the concentration of methanol to fall within a predetermined range when fuel is newly refilled into the tank.

  However, if the capacity of the fuel tank connected to the power supply is made relatively small as in the present embodiment and the auxiliary tank is connected and operated, only the auxiliary tank filled with a certain concentration of fuel is replaced with the consumption of fuel. It can be used for a long time without adjusting the methanol concentration.

FIG. 2A is an external view of a fuel cell unit according to the present invention, and FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view of a fuel cell power supply according to the present invention, and FIG. BRIEF DESCRIPTION OF THE DRAWINGS The external structure (a) and sectional structure (b) figure of the high voltage fuel cell unit concerning this invention. FIG. 2 is a sectional configuration diagram of a fuel supply port according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The external structure (a) and sectional structure (b) figure of the prismatic fuel cell unit concerning this invention. FIG. 4 is a current / voltage characteristic diagram of the fuel cell unit according to the first and second embodiments. BRIEF DESCRIPTION OF THE DRAWINGS The external structure (a) and sectional structure (b) figure of the cylindrical fuel cell unit concerning this invention. FIG. 2A is an external view of a high-voltage cylindrical fuel cell unit according to the present invention, and FIG. The external structure (a), (b) figure of the high voltage square cylinder type fuel cell unit concerning this invention. 1A and 1B are cross-sectional views of a high-voltage prismatic fuel cell unit according to the present invention. FIG. 13 is a current / voltage characteristic diagram of the high-voltage fuel cell unit according to the third and fourth embodiments. FIG. 7A is a diagram showing the external structure of a separator according to a comparative example, and FIG. The figure which shows the lamination structure of the battery concerning a comparative example. FIG. 4 is a structural diagram of a cell holder and a tightening band of a battery according to a comparative example. The power supply appearance structure (a) figure and the power supply and fuel tank coupling cross section (b) figure concerning a comparative example. FIG. 4 is a structural diagram of a cell holder and a tightening band of a battery according to a comparative example. FIG. 4 is a power supply appearance structure diagram according to a comparative example. FIG. 1A is an external view of a power supply constituted by a prismatic fuel cell unit according to the present invention, and FIG. FIG. 1 is a structural view of a cell holder for storing a square tubular fuel cell unit according to the present invention. FIG. 2A is an external view of a power supply constituted by a cylindrical fuel cell unit according to the present invention, and FIG. FIG. 2 is a structural view of a cylindrical fuel cell unit storage cell holder according to the present invention. FIG. 2A is an external view of a power supply including a high-voltage cylindrical fuel cell unit according to the present invention, and FIG. FIG. 2A is an external view of a power supply including a high-voltage prismatic fuel cell unit according to the present invention, and FIG. BRIEF DESCRIPTION OF THE DRAWINGS The external structure (a) and sectional structure (b) figure of the cylindrical fuel cell unit concerning this invention. FIG. 2A is an external view of a power supply including a high-voltage prismatic fuel cell unit according to the present invention, and FIG. FIG. 2A is an external view of a power supply constituted by a cylindrical fuel cell unit according to the present invention, and FIG. FIG. 4 is a cross-sectional view of a fuel tank and an auxiliary fuel tank of a power supply constituted by a cylindrical fuel cell unit according to the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... hollow support, 2 ... electrolyte membrane, 3 ... anode electrode, 4, 22 ... cathode electrode, 5 ... diffusion layer, 6 ... anode current collector, anode current collector, 7, 7a ... cathode current collector, cathode Current collector, 7b: cathode terminal plate tab, 8: porous layer, porous portion, 9: fuel outlet, 10: fuel supply port, 11: interconnector, 12: upper lid, 13: lower lid, 14: retaining Liquid material, 15: anode terminal plate, 16: gasket, 17: fastening band, 18: anode terminal, 19: cathode terminal, 20: fastening mesh, 21: rib, 23: laminated battery, 24: connector part,
51: Lid or gas-permeable membrane; 61: Battery performance of the unit manufactured in Example 1; 62: Battery performance of the unit manufactured in Example 2; 71: Battery of the unit manufactured in Example 3 Performance, 72: Battery performance of the unit manufactured in Example 4, 81: Separator, 82: Manifold, 83: Separator longitudinal sectional view, 84: Separator transverse sectional view, 85: Current-carrying aperture, power generation section aperture , 86: manifold opening, 87: manifold embedding, 88: groove embedding, 91: electrolyte membrane / electrode assembly, 92: liner, 93: gasket, 94: wicking material, 101: fuel cell unit , Fuel cell module, 102: fuel tank, 103: fuel supply port, 104: fuel, 105: cell holder, 106: battery fixing plate, 107: auxiliary fuel tank, 110: exhaust tank, 11 ... exhaust port.

Claims (12)

  A fuel cell having an anode for oxidizing a liquid fuel, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode, wherein the fuel cell has a hollow support structure, and has a hollow support structure. A fuel cell, wherein a power generation unit is formed by arranging an anode, an electrolyte membrane, and a cathode on an outer peripheral surface, and the fuel contacts the gas containing oxygen outside the power generation unit inside the hollow support.   A fuel cell having an anode for oxidizing a liquid fuel, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode, wherein the fuel cell has a hollow support structure, and the hollow support A fuel cell unit in which a plurality of fuel cells each having a power generation unit configured by arranging an anode, an electrolyte membrane, and a cathode on the outer peripheral surface of the fuel cell unit; and a container for storing the liquid fuel, A fuel cell power generator, which is electrically connected, wherein the liquid fuel is supplied from the container to the inside of the hollow support structure to generate power.   3. The fuel cell power generator according to claim 1, wherein a diffusion layer is arranged on an outer peripheral portion of the cathode.   4. The fuel cell according to claim 1, wherein the hollow support has electron conductivity.   5. The fuel cell according to claim 1, wherein the hollow support is filled with a holding material for holding the liquid fuel.   The power generation unit according to any one of claims 1 to 5, wherein the hollow support is provided with a plurality of power generation units including the anode, the electrolyte membrane, and the cathode on an outer peripheral surface thereof, and the power generation units are electrically connected to each other. A fuel cell, wherein the fuel cell is connected.   7. The fuel cell according to claim 2, wherein the container for storing the liquid fuel has a gas-liquid separation type exhaust hole.   A fuel cell having a hollow support structure, comprising: an anode for oxidizing a liquid fuel, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode on the outer peripheral surface of the hollow support. An electrolyte membrane and the cathode are formed in this order, and at least one power generation unit configured by disposing a diffusion layer on the outer periphery of the cathode is provided. Wherein the fuel cell unit is coupled to the fuel container storing the fuel, the fuel is supplied from the fuel container to each fuel cell unit, and the fuel cell units are electrically coupled. A fuel cell power generator characterized by the above-mentioned.   9. The fuel cell power generator according to claim 8, wherein the fuel is an aqueous methanol solution.   A fuel cell having an anode for oxidizing methanol, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode, wherein the fuel cell has a hollow support structure and an outer periphery of the hollow support. The surface has a plurality of power generation units including an anode, an electrolyte membrane, a cathode, and a diffusion layer, and the power generation units are electrically coupled to form a fuel cell unit. The plurality of fuel cell units supply the liquid fuel. A portable power supply, comprising: a fuel cell power generation device coupled to the container to be accommodated, wherein the plurality of fuel cell units are electrically coupled to each other.   A fuel cell having an anode for oxidizing methanol, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode, wherein the fuel cell has a hollow support structure and an outer periphery of the hollow support. The surface has a plurality of power generation units including an anode, an electrolyte membrane, a cathode, and a diffusion layer, and the power generation units are electrically coupled to form a fuel cell unit. The plurality of fuel cell units supply the liquid fuel. The plurality of fuel cell units are coupled to the container to be housed, and the plurality of fuel cell units have at least a secondary battery charged by a charger including a fuel cell power generation device electrically coupled to each other. Portable electronic devices. A fuel cell having an anode for oxidizing methanol, a cathode for reducing oxygen, and an electrolyte membrane for insulating the anode and the cathode, wherein the fuel cell has a hollow support structure and an outer periphery of the hollow support. The surface has a plurality of power generation units including an anode, an electrolyte membrane, a cathode, and a diffusion layer, and the power generation units are electrically coupled to form a fuel cell unit. The plurality of fuel cell units supply the liquid fuel. A portable electronic device coupled to the container to be housed, wherein the plurality of fuel cell units are driven by a fuel cell power generation device including a fuel cell power generation device electrically connected to each other.

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