JP2008243578A - Fuel cell - Google Patents

Abstract

A fuel cell capable of generating power stably without being affected by outside air is provided.
SOLUTION: A negative electrode that oxidizes fuel to obtain electrons and protons, an electrolyte layer through which protons pass, and an electrolyte layer sandwiched between the negative electrode and protons and electrons are reduced using oxygen as an active material to produce water. A power generation unit provided with a positive electrode to be generated, a housing in which the power generation unit is housed and provided with a gas permeable vent, and a ventilation rate of 1 cc / cm when the differential pressure is 125 Pa, which closes the vent. ^And a porous portion made of a porous porous material that is ² sec or less.
[Selection] Figure 5

Description

  The present invention relates to a fuel cell that generates electric power by converting combustion energy of fuel into electric energy.

  In recent years, as portable electronic devices such as mobile phones and laptop computers have become smaller, lighter, and more functional, batteries that are power sources for portable electronic devices have become lighter and larger in capacity. . As a battery for a portable electronic device, a lithium ion battery having a high driving voltage and a large capacity is generally used.

  However, lithium-ion batteries often have used batteries that can be recycled and are discarded without being collected, which causes environmental problems and is sufficient when used on laptop computers with high power consumption. There is a problem that continuous continuous use time cannot be guaranteed.

  In this regard, in recent years, fuel cells that directly convert combustion energy of fuel into electric energy have been developed. When a fuel cell supplies fuel to the negative electrode and oxygen to the positive electrode, an electrochemical reaction is generated by the action of the catalyst contained in each of the positive electrode and the negative electrode, and current can be taken out using the fuel as a supply source. it can. Fuel cells can achieve a capacity several times that of lithium-ion batteries, and can be used over and over again by replenishing fuel, and can continuously generate power for a long time. There is an advantage that it is very excellent in terms of environment because it does not generate substances.

  Fuel cells are classified into various types depending on the type of electrolyte and fuel. However, batteries for portable electronic devices operate at a low temperature of about room temperature, are resistant to vibration, and are easy to mass-produce. For this reason, a direct methanol fuel cell (DMFC) that supplies an aqueous methanol solution as a fuel is considered suitable. Among direct methanol fuel cells, a natural vaporization type passive DMFC that supplies high-concentration methanol directly to the negative electrode through a vaporization membrane is particularly preferable in terms of downsizing and simplification of the device. Research and development have been carried out (for example, see Patent Documents 1 to 3).

  FIG. 1 is a schematic configuration diagram of a natural vaporization type passive DMFC.

  The fuel cell 1 shown in FIG. 1 includes a power generation unit 10 that generates power, a fuel supply unit 20 that supplies fuel to the power generation unit 10, and an oxygen supply unit 30 that supplies oxygen to the power generation unit 10.

  The power generation unit 10 oxidizes gaseous fuel to generate an anode catalyst layer 11 that generates electrons and protons, and air that generates water by reducing protons and electrons generated in the anode catalyst layer 11 using oxygen as an active material. An electrode catalyst layer 12 and a solid electrolyte layer 13 which is provided between the fuel electrode catalyst layer 11 and the air electrode catalyst layer 12 and transports protons generated in the fuel electrode catalyst layer 11 to the air electrode catalyst layer 12. Has been.

  The fuel supply unit 20 includes a fuel electrode casing 21, a fuel tank 23 that stores methanol 22 that is liquid fuel, a liquid fuel vaporization film 24 that vaporizes the methanol 22 to generate gaseous fuel, and a liquid fuel vaporization film. The vaporized fuel diffusion layer 25 for diffusing the gaseous fuel vaporized at 24, the anode current collector 26 provided with a path capable of supplying the gaseous fuel to the anode catalyst layer 11, and the anode current collector 26 The fuel electrode gas diffusion layer 27 for diffusing the vaporized fuel and supplying the diffused gaseous fuel to the fuel electrode catalyst layer 11, and the carbon dioxide gas exhaust for discharging carbon dioxide generated by the electrochemical reaction in the fuel electrode catalyst layer 11 And an outlet 28.

  The oxygen supply unit 30 includes an air electrode side housing 31 and an air electrode current collector 32 for supplying oxygen supplied from the oxygen supply port 31a of the air electrode side housing 31 to the air electrode catalyst layer 12. And an air electrode gas diffusion layer 33 for diffusing oxygen supplied from the air electrode current collector 32 and supplying the diffused oxygen to the air electrode catalyst layer 12.

  The methanol 22 accommodated in the fuel tank 23 is vaporized by passing through the liquid fuel vaporization film 24, and the fuel electrode catalyst is passed through the vaporized fuel diffusion layer 25, the fuel electrode current collector 26, and the fuel electrode gas diffusion layer 27. Supplied to layer 11. In the fuel electrode catalyst layer 11, an electrochemical reaction as shown in the formula (1) is performed, and the vaporized fuel is oxidized to generate electrons and protons.

CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ Formula (1)
In the air electrode catalyst layer 12, an electrochemical reaction as shown in Formula (2) is performed, and protons that have passed through the solid electrolyte layer 13 are generated in the fuel electrode catalyst layer 11 and supplied to a mobile phone or the like. The generated electrons are reduced using oxygen in the air supplied from the oxygen supply port 31 a of the air electrode side housing 31.

6H ⁺ + (3/2) O ₂ + 6e ⁻ → 3H ₂ O Formula (2)
That is, when Expression (1) and Expression (2) are combined, water generated in the air electrode catalyst layer 12 is used in the fuel electrode catalyst layer 11 and the fuel electrode catalyst layer 11 in the fuel electrode 1 as a whole. By using the generated protons and electrons in the air electrode catalyst layer 12,
CH ₃ OH + (3/2) O ₂ → CO ₂ + 2H ₂ O Formula (3)
Thus, electricity is generated from the methanol 22 as the fuel.

By the way, carbon dioxide generated during power generation is exhausted from the oxygen supply port 31a through the carbon dioxide discharge port 28, and a part of the generated water is used in the fuel electrode catalyst layer 11 and excess water is vaporized. Then, it is exhausted from the oxygen supply port 31a in the state of water vapor. Patent Document 3 describes a fuel cell comprising 1 to 100 pieces of 0.1 mm ² to 10 mm ² around the through-holes in the oxygen supply port 31a. For example, if the through hole is 0.1 mm ² , the hole diameter is Φ0.18 mm, which is considered to be almost the same as the state where the oxygen supply port 31a is closed with carbon paper (approximately Φ0.20 mm). According to such a fuel cell, oxygen in the air can be reliably taken into the fuel cell 1 and carbon dioxide and water can be efficiently exhausted to the outside of the fuel cell. It is possible to avoid the trouble of entering.
JP 2004-206885 A JP 2006-54082 A JP 2002-373693 A

  However, in the technique described in Patent Document 3, when a mobile phone or the like is used outdoors on a windy day, outside air Q enters from the through hole of the oxygen supply port 31a and excessively vaporizes water in the fuel cell 1. As a result, the solid electrolyte layer 13 is dried and sufficient ion conductivity cannot be obtained, and there is a possibility that “dry out” may occur in which the power generation output of the fuel cell 1 is greatly deteriorated. The fuel cell is assumed to be mounted on a portable electronic device and used outdoors, and development of a fuel cell that stably generates power without being affected by outside air is desired.

  In view of the above circumstances, an object of the present invention is to provide a fuel cell that can stably generate power without being affected by outside air.

The fuel cell of the present invention that achieves the above object comprises a negative electrode that oxidizes fuel to obtain electrons and protons, an electrolyte layer through which protons pass, and an electrolyte layer sandwiched between the negative electrode and protons and electrons that are combined with oxygen. A power generation unit including a positive electrode that generates water by reduction as an active material;
A housing that houses the power generation unit and is provided with a gas permeable vent,
And a porous part made of a porous porous material having an air permeability of 1 cc / cm ² · sec or less when the differential pressure is 125 Pa.

  When water evaporates, from the side close to the water surface, the water-saturated layer near the water surface, the diffusion layer having a concentration gradient of water vapor, and the atmospheric pressure in which the vapor pressure is determined by the relative humidity and environmental temperature of the diffusion layer The evaporation rate of water is determined by the saturated vapor pressure of the layer near the water surface, the thickness of the diffusion layer, and the environmental vapor pressure of the environmental atmosphere layer. The thickness of the diffusion layer is greatly affected by the convection in the environment. The greater the convection in the environment, the thinner the diffusion layer and the faster the water evaporation rate. When there is almost no convection in the environment, the thickness of the diffusion layer can be calculated using the above-mentioned saturation vapor pressure, environmental vapor pressure, and interdiffusion coefficient of vapor pressure in air, and is almost constant. Become. From such analysis, it was found that in order to control the amount of water in the fuel cell, it is necessary to suppress convection in the fuel cell, that is, to reduce the influence of outside air.

The fuel cell according to the present invention includes a porous portion made of a porous material having an air permeability of 1 cc / cm ² · sec or less when the differential pressure is 125 Pa. By providing such a porous portion, the influence of outside air in the fuel cell can be suppressed to a level that does not affect the power generation performance of the fuel cell, and the electrolyte is appropriately humidified by water generated during power generation, and excess water Can be exhausted outside the fuel cell, and power can be stably generated without being affected by outside air.

  In the fuel cell of the present invention, it is preferable that the casing has a space formed between the power generation section and the porous section.

  Accurately adjust the amount of water in the fuel cell by forming an unstable diffusion layer with a water vapor concentration gradient in the space between the power generation unit and the porous unit that is not easily affected by outside air Can do.

Further, in the fuel cell of the present invention, a fuel tank for storing fuel,
It is preferable that the fuel supply part which supplies the fuel accommodated in the fuel tank to a negative electrode is provided.

  By storing the fuel in the fuel tank, power can be generated for a long time.

  In the fuel cell of the present invention, it is preferable that the fuel tank has a supply port for supplying fuel.

  By replenishing the fuel, the fuel cell can be used over and over again, and the continuous use time can be extended.

In the fuel cell of the present invention, the fuel is a liquid fuel,
The fuel tank is provided with at least an opening through which fuel passes,
The fuel supply unit is preferably a fuel vaporization layer provided in the opening for vaporizing fuel to be supplied to the negative electrode.

  According to this preferred fuel cell, a pump for supplying liquid fuel to the negative electrode can be omitted, and the fuel cell can be miniaturized.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell which can generate electric power stably without being influenced by external air can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 2 is an external perspective view of a mobile phone to which an embodiment of the present invention is applied.

  The mobile phone 100 according to the present embodiment has a built-in rechargeable battery, and can be driven by supplying power from the rechargeable battery by being connected to a charger and charging the rechargeable battery. By mounting a cradle (see FIG. 3) with a built-in battery, it can be driven using the power generated by the fuel cell.

  In the mobile phone 100 shown in FIG. 2, an upper casing 100A provided with a liquid crystal panel 101 and a lower casing 100B held by a user's hand are connected so as to be foldable around a hinge 100C.

  The upper housing 100A is provided with a liquid crystal panel 101 on which a telephone number, a TV program, a photographed image, and the like are displayed, and a speaker (see FIG. 4) inside, and a mouthpiece 102 for emitting sound emitted from the speaker. The lower casing 100B includes a selection button 104 used as a shutter button for selecting various functions and shooting, a push button 105 for inputting a telephone number, and a microphone inside. (See FIG. 4) is provided, and includes an earpiece 106 for transmitting a voice to the microphone, a charging terminal 107 for connecting a charger and a cradle (see FIG. 3), and the like.

  FIG. 3 is a diagram showing the mobile phone 100 mounted on the cradle.

  The cradle 200 holds the mobile phone 100 in a state where a telephone call and key operation are possible. The cradle 200 includes a connecting portion 210 connected to the charging terminal 107 shown in FIG. 2, a fuel cell 300, and a lid 220 that can be freely opened and closed. In the fuel cell 300, a power generation unit that generates power using fuel is housed in the cradle 200, and a gas exchange unit 301 that exhausts various gases generated in the power generation unit and supplies air to the power generation unit is provided in the cradle 200. It is exposed on the side. The fuel cell 300 will be described in detail later. The gas exchange part 301 corresponds to an example of a porous part referred to in the present invention.

  Next, the internal structure of the mobile phone 100 will be described.

  FIG. 4 is an internal block diagram of the mobile phone 100.

  As shown in FIG. 4, the mobile phone 100 includes a CPU 110, ROM 111, nonvolatile memory 112, RAM 113, microphone device 121, display device 122, speaker device 123, key device 124, camera device 125, clock 126, short distance device 131. The long-distance device 132, the media controller 140, and the rechargeable battery 151 are incorporated, and the cradle 200 shown in FIG. 3 is attached to connect the fuel cell 300. Various components shown in FIG. 4 are connected to each other via a bus.

  The CPU 110 has a function of executing various programs and controls the entire mobile phone.

  The ROM 111 stores various programs executed by the CPU 110 and various constants necessary for executing the various programs. The CPU 110 executes the programs stored in the ROM 111 using the RAM 113 as a work area.

  The nonvolatile memory 112 stores various information that can be rewritten, such as an address book and received e-mail.

  The microphone device 121 is a functional block that processes a microphone that picks up a user's voice and a voice picked up by the microphone.

  The speaker device 123 is a functional block that generates a speaker that outputs audio toward the user and an audio signal that drives the speaker.

  The camera device 125 is a block that manages the collection of image data by taking a picture, the display device 122 is a block that controls the display of an image on the liquid crystal panel 101 (see FIG. 2), and the key device 124 is a key that is used by the user. The operation detection block, and the clock 126 is a block for acquiring the current time.

  The media controller 140 reads data from the loaded recording medium 141 and writes image data generated by the camera device 125 to the recording medium 141.

  The short-distance device 131 is for transmitting an image, a telephone number, or the like to an external device at a short distance by infrared communication without going through a base station (not shown).

  The long-distance device 132 is for making a call or sending / receiving an e-mail via a base station (not shown).

  The rechargeable battery 151 is charged by being connected to a charger and supplies power to the mobile phone 100.

  The fuel cell 300 generates power using fuel and supplies power to the mobile phone 100, and corresponds to one embodiment of the fuel cell of the present invention.

  The mobile phone of this embodiment is basically configured as described above.

  Next, the fuel cell 300 will be described in detail.

  FIG. 5 is a schematic configuration diagram of the fuel cell 300.

  The fuel cell 300 includes a power generation unit 310 that generates power, a fuel supply unit 320 that supplies fuel to the power generation unit 310, and an oxygen supply unit 330 that supplies oxygen to the power generation unit 310.

  The power generation unit 310 includes a fuel electrode catalyst layer 311, an air electrode catalyst layer 312, and a solid electrolyte layer 313.

The fuel electrode catalyst layer 311 is supplied with gaseous fuel (in this embodiment, methanol: CH ₃ OH) and generates electrons (e ⁻ ) and protons (H ⁺ ). It corresponds to an example.

The air electrode catalyst layer 312 generates water (H ₂ O) by reducing protons (H ⁺ ) and electrons (e ⁻ ) generated in the fuel electrode catalyst layer 311 using oxygen (O ₂ ) as an active material. Yes, and corresponds to an example of the positive electrode referred to in the present invention. As the air electrode catalyst layer 312, a solid electrolyte layer is prepared by mixing a catalyst or catalyst carrier capable of generating an electrochemical reaction that generates water from protons and oxygen and a proton conductive polymer solid electrolyte. What was apply | coated to 313 and the air electrode gas diffusion layer 333 (after-mentioned) is applied.

The solid electrolyte layer 313 is provided between the fuel electrode catalyst layer 311 and the air electrode catalyst layer 312 and transports protons (H ⁺ ) generated in the fuel electrode catalyst layer 311 to the air electrode catalyst layer 312. This corresponds to an example of the electrolyte layer according to the present invention. As the solid electrolyte layer 313, a polymer material having proton conductivity can be applied. For example, a perfluorosulfonic acid resin film is preferable. Specifically, Nafion N112 (manufactured by DuPont: registered) Trademark) and the like can be applied.

  The fuel supply unit 320 includes a fuel electrode side casing 321, a fuel tank 323, a liquid fuel vaporization film 324, a vaporized fuel diffusion layer 325, a fuel electrode current collector 326, and a fuel electrode gas diffusion layer 327. And a carbon dioxide gas outlet 328.

  The fuel tank 323 stores methanol 322, which is a liquid fuel, and is detachably attached to the cradle 200 shown in FIG. The fuel tank 323 corresponds to an example of the fuel tank according to the present invention.

  The liquid fuel vaporization film 324 vaporizes methanol 322 oozing out from the fuel tank 323 to generate a gaseous fuel. The liquid fuel vaporization film 324 is an example of a fuel supply unit according to the present invention, and is a fuel vaporization layer according to the present invention. It corresponds to an example. The liquid fuel vaporized film 324 is a film capable of separating the fuel methanol 322 and the vaporized fuel diffusion layer 325, and is a porous film having separability due to surface tension, or a non-porous polymer material having permeation impregnation properties. Etc. are suitable. For example, Nafion (manufactured by DuPont: registered trademark), Flemion (manufactured by Asahi Glass Co., Ltd.), Aciplex (manufactured by Asahi Kasei Co., Ltd.), and the like, which are perfluoro resins, can be used because they are insoluble in a high-concentration aqueous methanol solution.

  The vaporized fuel diffusion layer 325 diffuses the gaseous fuel vaporized by the liquid fuel vaporized film 324. The end portion of the vaporized fuel diffusion layer 325 has a configuration exposed to the outside of the power generation unit 310 of the fuel cell 300, and the exposed portion has a carbon dioxide discharge port 328 that discharges carbon dioxide generated in the power generation unit 310. Forming.

  The fuel electrode current collector 326 is for supplying gaseous fuel to the fuel electrode catalyst layer 311. As the fuel electrode current collector 326, an electrically conductive highly corrosion-resistant alloy (for example, SUS304, SUS316, etc.) whose surface is Au-plated can be applied, and gaseous fuel or oxygen in the air is used as the fuel electrode catalyst. Preferably, the layer 311 has a shape such as a mesh, an expanded metal, or a foam metal that can be introduced into the layer 311.

  The fuel electrode gas diffusion layer 327 diffuses the vaporized fuel supplied from the fuel electrode current collector 326 and supplies the diffused gaseous fuel to the fuel electrode catalyst layer 311. The anode gas diffusion layer 327 preferably has a porous body shape that can introduce gaseous fuel or oxygen in the air into the anode catalyst layer 311, and the anode electrode catalyst layer 311 and the anode current collector. It is necessary to have conductivity in a state of being disposed between the 326 and the H.326. As such a material, for example, carbon paper (manufactured by Toray Industries, Inc.) can be applied.

  The oxygen supply unit 330 includes an air electrode side housing 331, a gas exchange unit 301, an air electrode current collector 332, and an air electrode gas diffusion layer 333.

  The air electrode side housing 331 is provided with a vent hole 331a, and the gas exchange unit 301 closes the vent hole 331a. The air electrode side casing 331 corresponds to an example of the casing according to the present invention, and the vent hole 331a corresponds to an example of the vent hole according to the present invention.

The gas exchange part 301 is made of a gas-permeable porous material having an air permeability of 1 cc / cm ² · sec or less when the differential pressure is 125 Pa, and corresponds to an example of the porous part referred to in the present invention. A space P is provided between the gas exchange unit 301 and the power generation unit 310. As the gas exchange unit 301, a Durapore membrane filter HVHP14250 (manufactured by Nippon Millipore: air permeability 0.15 cc / cm ² · sec) or the like can be applied.

  The air electrode current collector 332 is for supplying oxygen supplied from the gas exchange unit 301 to the air electrode catalyst layer 312, and the same material as that of the fuel electrode current collector 326 described above can be applied. .

  The air electrode gas diffusion layer 333 is for diffusing oxygen supplied from the air electrode current collector 332 and supplying the diffused oxygen to the air electrode catalyst layer 312. The same material as 327 can be applied.

  FIG. 6 is a cross-sectional view showing the side of the mobile phone 100 attached to the cradle 200 shown in FIG.

  The cross-sectional view shown in FIG. 6 corresponds to the cross-sectional view when the fuel cell 300 shown in FIG. 5 is cut in the horizontal direction of the drawing. As shown in FIG. 6, the cradle 200 is provided with a lid 220, and the fuel can be supplied to the fuel tank 323 by opening the lid 220 and pouring methanol from the fuel supply port 323 a. The fuel supply port 323a corresponds to an example of a supply port according to the present invention. In the present embodiment, spaces P are also provided between the upper and lower surfaces of the power generator 310 and the housing.

  The methanol 322 stored in the fuel tank 323 is vaporized by passing through the liquid fuel vaporization film 324, and the fuel electrode catalyst is passed through the vaporized fuel diffusion layer 325, the fuel electrode current collector 326, and the fuel electrode gas diffusion layer 327. Supplied to layer 311.

  In the fuel electrode catalyst layer 311, carbon dioxide, electrons, and protons are generated using vaporized fuel and water. The generated carbon dioxide is exhausted to the outside of the fuel cell 300 through the carbon dioxide discharge port 328, and the generated electrons are transmitted to the circuit unit 230 to the mobile phone 100 through the connection unit 210 and the charging terminal 107. Supplied. The electrons returned from the mobile phone 100 are supplied to the air electrode catalyst layer 312. The generated protons are supplied to the air electrode catalyst layer 312 through the solid electrolyte layer 313.

  In the air electrode catalyst layer 312, protons and electrons are reduced using oxygen in the air supplied from the gas exchange unit 301 to generate water. The generated water is used not only for the electrochemical reaction on the fuel electrode catalyst layer 311 side but also for humidification of the solid electrolyte layer 313, and the excess is exhausted from the gas exchange unit 301.

In the present embodiment, the gas exchange unit 301 is made of a porous porous material having an air permeability of 1 cc / cm ² · sec or less when the differential pressure is 125 Pa, and the inside of the fuel cell 300 is convected by the outside air Q. Since it is hardly affected, even when the mobile phone 100 is used outdoors with strong wind, the solid electrolyte layer 313 can be humidified while keeping the amount of water in the fuel cell 300 moderately and stably. It can generate electricity.

  Further, in the vicinity of the air electrode catalyst layer 312, a water surface vicinity layer saturated with water generated in the air electrode catalyst layer 312, a diffusion layer having a concentration gradient of water vapor, and an environmental atmosphere layer whose vapor pressure is determined by an environmental temperature, etc. However, in this embodiment, the space P is provided between the power generation unit 310 and the gas exchange unit 301, and a diffusion layer is formed in the space P that is not easily affected by outside air. The amount of water in the battery 300 can be stabilized with high accuracy.

Examples of the present invention will be described below.
(Evaluation methods)
In the fuel cell having the same configuration as the fuel cell 300 shown in FIG. 5, an example in which the gas exchange unit 301 was changed and a comparative example were prepared.

  The following components were used for the components constituting the power generation unit 310.

Fuel electrode catalyst layer 311: Pt—Ru alloy supported catalyst TEC61E54 (Tanaka Kikinzoku Co., Ltd.)
Air electrode catalyst layer 312: Pt-supported catalyst TEC10E50E (Tanaka Kikinzoku Co., Ltd.)
Solid electrolyte layer 313: Nafion N112 (manufactured by DuPont: registered trademark)
The following was used as the gas exchange unit 301.

  Table 1 is a table showing materials constituting the gas exchange unit 301.

  Three examples and two comparative examples in which the air permeability was adjusted by stacking one or a plurality of materials shown in Table 1 were prepared.

  Table 2 is a table | surface which shows the air permeability of an Example and a comparative example.

The fuel cell composed of the above components was installed in an evaluation fuel cell system, and the output value of the fuel cell at an environmental wind speed of 5 m / sec and an environmental wind speed of 1 m / sec was measured. Evaluation result when the maximum output value of the fuel cell among the measured output values at the environmental wind speed of 1 m / sec is the maximum output value of the fuel cell, and the measured output value at the environmental wind speed of 5 m / sec is 70% or more of the maximum output value. Was determined to be good.
(Evaluation results)
FIG. 7 is a graph showing the evaluation results.

  The horizontal axis of the graph represents the air permeability shown in Table 2, and the vertical axis of the graph represents the measured output value of the fuel cell.

  In addition, the evaluation results of the examples and comparative examples when the environmental wind speed is 1 m / sec are plotted with black squares, and the evaluation results of the examples and comparative examples when the environmental wind speed is 5 m / sec are black diamonds. The evaluation result of Comparative Example 2 when the environmental wind speed is 1 m / sec is plotted with a white square, and the evaluation result of Comparative Example 2 when the environmental wind speed is 5 m / sec is a white diamond. It is plotted.

  As shown in FIG. 7, at the environmental wind speed of 5 m / sec, in Examples 1, 2 and 3, the measured output value exceeded 70% of the maximum output value, and the evaluation result was determined to be good. In Comparative Examples 1 and 2, the measured output value was significantly lower than the maximum output value, and the evaluation result was determined to be defective. In Comparative Examples 1 and 2, since the gas exchange unit 301 has a high air permeability, the solid electrolyte layer 313 is dried by the wind in a strong wind such as an environmental wind speed of 5 m / sec, and good ion conductivity can be obtained. This is thought to be because there is not.

  From the above results, the usefulness of the present invention was confirmed.

It is a schematic block diagram of a natural vaporization type passive DMFC. 1 is an external perspective view of a mobile phone to which an embodiment of the present invention is applied. It is a figure which shows the mobile telephone in the state with which the cradle was mounted | worn. It is an internal block diagram of a mobile phone. It is a schematic block diagram of a fuel cell. It is sectional drawing which shows the side surface side of the mobile telephone with which the cradle shown in FIG. 3 was mounted | worn. It is a graph which shows an evaluation result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Mobile phone 100A Upper housing | casing 100B Lower housing | casing 100C Intermediate housing | casing 101 Liquid crystal panel 102 Mouthpiece 104 Selection button 105 Push button 106 Earpiece 110 CPU
111 ROM
112 Nonvolatile memory 113 RAM
121 Microphone device 122 Display device 123 Speaker device 124 Key device 125 Camera device 126 Clock 131 Short-distance device 132 Long-distance device 140 Media controller 151 Rechargeable battery 200 Cradle 210 Connection unit 220 Lid 300 Fuel cell 301 Gas exchange unit 310 Power generation unit 311 Fuel Electrode catalyst layer 312 Air electrode catalyst layer 313 Solid electrolyte layer 320 Fuel supply unit 321 Fuel electrode side housing 323 Fuel tank 323a Fuel supply port 324 Liquid fuel vaporization film 325 Vaporized fuel diffusion layer 326 Fuel electrode current collector 327 Fuel electrode gas diffusion Layer 328 Carbon dioxide gas outlet 330 Oxygen supply unit 331 Air electrode side housing 332 Air electrode current collector 333 Air electrode gas diffusion layer

Claims (5)

A negative electrode that oxidizes fuel to obtain electrons and protons, an electrolyte layer through which the protons pass, and an electrolyte layer sandwiched between the negative electrode and the protons and electrons that are reduced using oxygen as an active material to form water A power generation unit with a positive electrode for generating
A housing that houses the power generation unit and is provided with a gas permeable air hole;
A fuel cell comprising: a porous portion made of a porous porous material that blocks the air hole and has an air permeability of 1 cc / cm ² · sec or less when the differential pressure is 125 Pa.   The fuel cell according to claim 1, wherein the casing has a space formed between the power generation unit and the porous unit. A fuel tank containing the fuel;
The fuel cell according to claim 1, further comprising: a fuel supply unit that supplies the fuel stored in the fuel tank to the negative electrode.   The fuel cell according to claim 3, wherein the fuel tank is provided with a supply port for supplying fuel. The fuel is a liquid fuel;
The fuel tank is provided with at least an opening through which the fuel passes,
5. The fuel cell according to claim 3, wherein the fuel supply unit is a fuel vaporization layer provided in the opening to vaporize the fuel and supply the fuel to the negative electrode.

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