JP2009099491A - Fuel cell system and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of continuing power generation by a fuel cell without supplying hydrogen from the outside, and to provide electronic equipment having the same. <P>SOLUTION: The fuel cell system is provided with the fuel cell having an electrolyte membrane, a fuel electrode formed on one surface of the electrolyte membrane, and an air electrode formed on the other surface of the electrolyte membrane, an air chamber which stores air including steam generated in the air electrode by the power generation reaction of the fuel cell, a fuel chamber which holds fuel, a hydrogen generating mechanism which generates hydrogen by making the air including steam react with a hydrogen generating material, a hydrogen separating mechanism which is interposed between the fuel chamber and the hydrogen generating mechanism and separates hydrogen from the hydrogen generating mechanism to supply it to the fuel chamber, and an introduction mechanism which introduces the air including steam from the air chamber into the hydrogen generating mechanism. An electronic equipment having the fuel cell system is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system in which a fuel cell having good power generation characteristics is incorporated, and an electronic device equipped with the fuel cell system.

In recent years, energy problems and environmental problems have attracted attention, and one of the means for solving these problems is the use of fuel cells capable of high-efficiency power generation. When a fuel cell uses hydrogen as a fuel, only water is discharged. Therefore, the emission of harmful substances such as nitrogen compounds (NO _x ) and sulfur compounds (SO _x ) generated by burning fossil fuels such as petroleum, and carbon dioxide (CO ₂ ), which is said to be one cause of global warming, is suppressed. It is a highly efficient power generation system that can Hydrogen, which is mainly used as fuel, has been attracting attention as a clean energy that can replace fossil fuels, which are currently being depleted, and has the potential to contribute to the protection of the global environment and the establishment of a recycling society.

  A polymer polymer fuel cell (hereinafter referred to as “PEFC”) is a form of a fuel cell using a solid polymer membrane, and has an advantage of high output at room temperature and easy miniaturization. A fuel cell represented by PEFC typically has a fuel electrode, a fuel diffusion layer, a fuel electrode conductive layer, an electrolyte membrane, an air electrode, an air diffusion layer, and an air electrode conductive layer. Then, hydrogen is introduced into the fuel electrode and air is introduced into the air electrode, and electric energy is taken out from the following reaction.

Fuel electrode: H ₂ → 2H ++ 2e ⁻ (oxidation reaction)
Air electrode: 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (reduction reaction)
One of the technical issues for the practical application of PEFC is the lack of energy density of the fuel cell. This is because, at present, the fuel having the highest reaction rate in the oxidation reaction of the fuel electrode is hydrogen. This is because hydrogen is a gas at room temperature and has a low density per volume, and when hydrogen is supplied to the fuel cell by a high-pressure cylinder method, an increase in the size of the fuel cell system is inevitable. Therefore, the high-pressure cylinder fuel cell system is not suitable for portable / communication equipment.

  For this reason, means for generating and supplying hydrogen in the fuel cell system has been introduced to reduce the size of the fuel cell system. Examples of means for generating and supplying hydrogen include hydrogen generation by high-temperature reforming of high energy density hydrocarbon fuels, hydrogen generation from hydrogen storage alloys, hydrolysis of hydrogen generating materials, or hydrogen generation by oxidation, etc. Is mentioned.

  Of these, external heating is required for high-temperature reforming of hydrocarbon fuels and hydrogen generation from hydrogen storage alloys. In a fuel cell system using a hydrocarbon-based fuel or a hydrogen storage alloy, the energy required for this heating includes one that uses the combustion heat of the fuel or one that uses the power generation energy of the fuel cell. On the other hand, the hydrogen generation material does not require heating for hydrolysis or oxidation, and hydrogen can be generated at room temperature. Therefore, in the fuel cell system using the hydrogen generating material, complicated heating structure and heat insulation structure can be omitted.

  However, hydrolysis of the hydrogen generating material or generation of hydrogen by oxidation has other problems, and one of them is that corresponding water is required to generate hydrogen. The following shows the hydrolysis or oxidation reaction of typical hydrogen generating materials.

CaH ₂ + 2H ₂ O → Ca (OH) ₂ + 2H ₂
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂
NH ₃ BH ₃ + 2H ₂ O → NH ₄ ⁺ + BO ₂ ⁻ + 3H ₂
Al + 3H ₂ O → Al (OH) ₃ + 3 / 2H ₂
Generally used hydrogen generating materials have high energy density per weight / volume, but in fuel cell systems that combine hydrogen generating material and water required for reaction, the energy density per weight / volume is high. There is a problem that becomes lower. In particular, in small fuel cell systems suitable for portable electronic devices, hydrogen is generated so that the energy density obtained by dividing the electric energy generated by the generated hydrogen by the weight and volume of the hydrogen generating material and water is increased. It is important to select the material.

To solve this problem, Patent Document 1 proposes a fuel cell system having a structure for supplying water (steam) of a product generated by power generation of a fuel cell to a hydrogen generating material. In this structure, water necessary for hydrogen generation is covered by water generated in the fuel cell system, so that it is not necessary to carry water. Hydrogen generated from the hydrogen generating material is supplied to the fuel cell, and the hydrogen is generated again by oxidizing the hydrogen and generating electricity, and the operation of the fuel cell is performed without the need to add hydrogen from the outside. It is possible to last.
JP-T-2006-503414

  However, in order to realize the water supply system according to Patent Document 1 described above with PEFC, air containing water vapor generated at the air electrode is supplied to the hydrogen generating material. In this case, since hydrogen generated from the hydrogen generating material and air containing water vapor cannot be separated, a mixed gas of hydrogen and air containing water vapor is supplied to the fuel electrode of the fuel cell. Then, since the density of hydrogen contained per unit volume of the mixed gas is low, the output density obtained by the fuel cell is low, and when air enters the fuel electrode, it is contained in hydrogen and air as shown below at the fuel electrode. Reacts with oxygen.

H ₂ + 1 / 2O ₂ → H ₂ O
This reaction is a hydrogen combustion reaction, and the energy used for the combustion reaction cannot be taken out as electric energy. That is, the hydrogen consumed in this combustion reaction cannot contribute to power generation, resulting in a decrease in hydrogen utilization efficiency. Further, the reaction field of the fuel electrode is reduced due to the combustion reaction described above, and the output density of the fuel cell is lowered. For this reason, Patent Document 1 describes that use in a solid oxide fuel cell (SOFC) in which water as liquid is generated at the fuel electrode is the most profitable form than PEFC in which water is generated at the air electrode. .

  The present invention has been made in view of such a situation, and means for separating hydrogen that improves the utilization efficiency of hydrogen obtained from a hydrogen generating material, the hydrogen separation mechanism thereof, and the hydrogen separation mechanism of the present invention. It is an object of the present invention to provide a fuel cell system and an electronic device having a high output density obtained by providing the above.

  The present invention relates to a fuel cell having an electrolyte membrane, a fuel electrode formed on one surface of the electrolyte membrane, and an air electrode formed on the other surface of the electrolyte membrane, and an air electrode by a power generation reaction of the fuel cell. An air chamber for accumulating air containing water vapor generated in step 1, a fuel chamber for holding fuel, a hydrogen generation mechanism for generating hydrogen by reacting air containing water vapor and a hydrogen generating material, and a fuel chamber and hydrogen generation The present invention relates to a fuel cell system comprising a hydrogen separation mechanism that is interposed in the mechanism and separates hydrogen from a hydrogen generation mechanism and supplies the hydrogen to a fuel chamber, and an introduction mechanism that introduces air containing water vapor from the air chamber into the hydrogen generation mechanism.

  The fuel cell system of the present invention preferably further includes a heat supply mechanism for supplying heat generated by hydrolysis or oxidation reaction of the hydrogen generating material in the hydrogen generation mechanism to the fuel cell.

  In the fuel cell system of the present invention, the introduction mechanism preferably includes a valve for adjusting the amount of water vapor introduced into the hydrogen generation mechanism.

The fuel cell system of the present invention preferably includes an air supply fan.
In the fuel cell system of the present invention, it is preferable that the internal pressure P1 in the hydrogen generation mechanism is larger than the internal pressure P2 in the fuel chamber.

  In the fuel cell system of the present invention, it is preferable that a leak valve for adjusting the pressures of the internal pressure P1 and the internal pressure P2 is provided in at least one of the hydrogen generation mechanism and the fuel chamber.

  In the fuel cell system of the present invention, the hydrogen generating material in the hydrogen generating mechanism is preferably arranged such that the gap between the hydrogen generating materials is smaller toward the downstream than the upstream where the air containing water vapor is introduced. .

  Further, in the fuel cell system of the present invention, the hydrogen generating material has a stoichiometric number of hydrogen generated from the stoichiometric number of water vapor necessary for generating hydrogen for adjusting the internal pressure P1 and the internal pressure P2. It is preferable to have a large hydrogen generating material and provide a check valve between the air chamber and the hydrogen generation mechanism.

In the fuel cell system of the present invention, the hydrogen generating material is
A hydride represented by the general formula MH _4-n ,
A hydride represented by the general formula M (BH ₄ ) _4-n ,
A hydride represented by the general formula M (AlH ₄ ) _4-n ,
(Here, M is an alkali metal of Group 1A of the periodic table, an alkaline earth metal of Group 2A, and n is an integer of 0 to 3),
NH ₃ BH ₃ , and one or a mixture of two or more selected from the group of metal fine particles selected from Al, Fe and Mg are preferable.

Further, in the fuel cell system of the present invention, the hydrogen generating material, LiH, NaH, KH, in _{MgH 2, CaH 2, AlH 3} , LiBH 4, NaBH 4, 1 or more compounds selected from LiAlH ₄ and NaAlH ₄ Preferably there is.

In the fuel cell system of the present invention, the hydrogen generating material is preferably one or a mixture of two or more selected from NaBH ₄ , LiBH ₄ and NH ₃ BH ₃ .

  Further, in the fuel cell system of the present invention, the hydrogen separation mechanism includes a polymer membrane made of polyimide or polysulfone, an inorganic porous membrane made of porous ceramics, and a metal support made of niobium, tantalum or vanadium, or porous It is preferably any one selected from palladium or an alloy film in which the surface of an inorganic porous support made of glass, porous ceramics or porous aluminum oxide is coated with palladium or a palladium alloy.

  Further, in the fuel cell system of the present invention, the fuel held in the fuel chamber is methanol, ethanol, dimethoxymethane, formic acid, methyl formate, dimethyl ether, butane, ascorbic acid, hydrazine, ammonia, sulfurous acid, bisulfite, thiosulfuric acid. It is preferably one or a mixture of two or more selected from salts, dithionite, hypophosphorous acid and phosphorous acid.

  In the fuel cell system of the present invention, the fuel held in the fuel chamber is preferably gaseous fuel.

  In the fuel cell system of the present invention, the gaseous fuel is preferably at least one selected from hydrogen, dimethyl ether, butane, and ammonia.

  In the fuel cell system of the present invention, the fuel is a liquid fuel or a solid fuel dissolved in a liquid, and at least one selected from methanol, ethanol, dimethoxymethane, formic acid, methyl formate, ascorbic acid and hydrazine. It is preferable that

  In the fuel cell system of the present invention, it is preferable that a gas-liquid separation membrane is further provided in the fuel chamber.

  In the fuel cell system of the present invention, the gas-liquid separation membrane is preferably a porous layer.

  Further, in the fuel cell system of the present invention, the fuel cell system includes a plurality of fuel cells, has a partition separating hydrogen generated by the hydrogen generation mechanism and fuel in the fuel chamber, and is supplied with fuel in the fuel chamber; It is preferable to include a fuel cell to which hydrogen generated by the hydrogen generation mechanism and fuel in the fuel chamber are supplied.

  Moreover, this invention relates to an electronic device provided with the above-mentioned fuel cell system.

  Since the fuel cell system of the present invention has a hydrogen separation mechanism, hydrogen generated from the hydrogen generating material can be separated from the air and supplied to the fuel cell. It is possible to improve the utilization efficiency of the generated hydrogen. In addition, the volume and weight of the fuel cell system can be suppressed, and the entire fuel cell system including the fuel cell can be reduced in weight and size.

  Furthermore, since the temperature of the fuel and the fuel cell can be easily raised using the heat generated by the hydrolysis or oxidation reaction of the hydrogen generating material, the output density obtained from the fuel cell can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In addition, dimensional relationships such as length, size, and width in the drawings are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensions.

<Basic configuration of fuel cell system>
FIG. 1 is a perspective view schematically showing an embodiment of the fuel cell system of the present invention. Hereinafter, a description will be given based on FIG.

  The fuel cell system of the present invention mainly includes a fuel cell 10, an air chamber 50, a fuel chamber 80, a hydrogen generation mechanism 30, a hydrogen separation mechanism 20, and an introduction mechanism 90. The fuel cell 10 mainly includes an electrolyte membrane 5, a fuel electrode 4 formed on one surface of the electrolyte membrane 5, and an air electrode 6 formed on the other surface of the electrolyte membrane 5. The fuel cell 10 further includes the fuel diffusion layer 3 and the fuel electrode conductive layer 2 on the fuel electrode 4 side, and the air diffusion layer 7 and the air electrode conductive layer 8 on the air electrode 6 side.

  As a power generation reaction in the fuel cell 10, as described below, a reduction reaction occurs on the air electrode 6 side that is the positive electrode, and an oxidation reaction occurs on the fuel electrode 4 side that is the negative electrode.

Fuel electrode: H ₂ → 2H ++ 2e ⁻ (oxidation reaction)
Air electrode: 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (reduction reaction)
The air chamber 50 is a space in which air containing water vapor generated at the air electrode 6 by the power generation reaction of the fuel cell 10 can be accumulated. The fuel chamber 80 is a space that can hold fuel such as hydrogen necessary for the power generation reaction of the fuel cell 10.

  The air chamber 50 and the hydrogen generation mechanism 30 are connected by an introduction mechanism 90, and air containing water vapor accumulated in the air chamber 50 is introduced into the hydrogen generation mechanism 30 by the introduction mechanism 90. The hydrogen generating material 30 holds the hydrogen generating material 40. In the hydrogen generating mechanism 30, the air containing the water vapor and the hydrogen generating material 40 react to generate hydrogen.

  The introduction mechanism 90 can include a valve 60. At this time, the amount of air containing water vapor introduced from the air chamber 50 to the hydrogen generation mechanism 30 by the introduction mechanism 90 can be adjusted by opening and closing the valve 60.

  The hydrogen generation mechanism 30 is adjacent to the fuel chamber 80, and the hydrogen separation mechanism 20 is interposed between the hydrogen generation mechanism 30 and the fuel chamber 80. In the configuration shown in FIG. 1, the hydrogen generation mechanism 30 and the fuel chamber 80 are separated by the hydrogen separation mechanism 20. At this time, it is preferable that the hydrogen generation mechanism 30 and the fuel chamber 80 are completely blocked by the hydrogen separation mechanism 20. The hydrogen separation mechanism 20 separates hydrogen from a mixture of air containing water vapor introduced into the hydrogen generation mechanism 30 and the generated hydrogen, and supplies the hydrogen to the fuel chamber 80. As the hydrogen separation mechanism 20, a hydrogen permeation mechanism that does not permeate gases other than hydrogen can be used. As the hydrogen separation mechanism 20, for example, a hydrogen separation membrane can be used. Specifically, a polymer membrane made of polyimide or polysulfone, an inorganic porous membrane made of porous ceramics, and a metal made of niobium, tantalum or vanadium. It is preferably any one selected from palladium or an alloy film in which the surface of an inorganic porous support made of porous glass, porous ceramics or porous aluminum oxide is coated with palladium or a palladium alloy.

  In the configuration of FIG. 1, the hydrogen separation mechanism 20 serves as a heat supply mechanism that transfers heat generated by hydrolysis or oxidation reaction of the hydrogen generating material in the hydrogen generation mechanism 30 to the fuel chamber and supplies the fuel cell 10. Also plays a role. By supplying the heat to the fuel cell 10, the power generation efficiency of the fuel cell system can be improved and the output density can be improved.

  In the air chamber 50, external air can be supplied by the air supply fan 70, and the hydrogen generation mechanism 30 is provided with a discharge port for appropriately discharging the air containing water vapor introduced by the introduction mechanism 90. . The air supply fan 70 has a role of supplying air also to the air electrode 6.

  Further, in order to prevent hydrogen generated by the hydrogen generation mechanism 30 from diffusing to the air electrode 6 side and being oxidized at the air electrode 6, the air flow is directed so that the gas flow direction is from the air chamber 50 to the hydrogen generation mechanism 30. It is preferable to appropriately set the air supply fan 70 for this purpose.

  Next, the operation of the fuel cell system of the present invention will be described. First, as a power generation reaction in the fuel cell 10 described above, a reduction reaction occurs on the air electrode 6 side that is the positive electrode, and an oxidation reaction occurs on the fuel electrode 4 side that is the negative electrode. At this time, the air diffusion layer 7 has a role of uniformly supplying air to the air electrode 6 and a function of facilitating discharge of water (water vapor) generated by the air electrode 6. Has the role of supplying fuel uniformly. The electric energy generated by the power generation reaction of the fuel cell 10 can be taken out by a metal wire or the like that is electrically connected to the air electrode conductive layer 8 and the fuel electrode conductive layer 2. Water vapor generated at the air electrode 6 is accumulated in the air chamber 50. At the same time, external air is supplied to the air chamber 50 by the air supply fan 70. The air containing water vapor in the air chamber 50 is introduced into the hydrogen generation mechanism 30 by the introduction mechanism 90. At this time, the amount of air containing water vapor introduced into the hydrogen generation mechanism 30 by the valve 60 can be controlled. That is, the amount of water vapor introduced into the hydrogen generation mechanism 30 can be controlled.

  The hydrogen generating mechanism 30 is provided with a hydrogen generating material 40, and hydrogen is generated when the water vapor and the hydrogen generating material 40 react with each other. By controlling the amount of water vapor introduced into the hydrogen generation mechanism 30 with the valve 60 described above, the amount of hydrogen generated can be controlled. In order to stop the power generation of the fuel cell 10, it is possible to close the valve 60 and stop the supply of water vapor. The generated hydrogen is separated by the hydrogen separation mechanism 20, and only hydrogen is supplied to the fuel chamber 80. Further, when hydrogen is generated at the same time, heat is generated by hydrolysis or oxidation reaction of the hydrogen generating material 40. The heat in the hydrogen generation mechanism 30 is supplied to the fuel cell. Specifically, in the configuration of FIG. 1, the heat is transferred to the fuel chamber 80 via the hydrogen separation mechanism 20 that also serves as a heat supply mechanism. The heat supplied to the fuel chamber 80 by this heat supply mechanism is used to raise the temperature of the fuel and the fuel cell. Further, fuel is previously held in the fuel chamber 80, and hydrogen derived from the fuel is also held in the fuel chamber 80. In addition, when the fuel is not held in the fuel chamber 80 in advance, the first water (steam) necessary for hydrolysis or oxidation of the hydrogen generating material 40 cannot be supplied from water generated by the power generation of the fuel cell. It will be. In this case, the first water is not water generated by power generation of the fuel cell but only water vapor originally contained in the air supplied from the air supply fan 70 to the air chamber 50, and the amount of hydrogen generated by the hydrogen generation mechanism 30 is reduced. It will be affected by the amount of water vapor in the outside air, that is, the humidity. Since the humidity of the outside air is not always constant, it is not possible to generate power stably and continuously. Therefore, it is preferable that the fuel is held in the fuel chamber 80 in advance.

  The hydrogen generating material 40 in the present invention is a compound mainly combined with hydrogen and has a property of generating hydrogen by thermal decomposition, hydrolysis, or oxidation reaction. The hydrogen generating material 40 is preferably in the form of a stable powder that does not decompose naturally and generate hydrogen. The particle size of the hydrogen generating material 40 is preferably 1 μm to 5 mm, and more preferably 1 μm to 100 μm. This is because the smaller the particle size, the larger the area exposed on the surface of the hydrogen generating material, and the reaction rate can be improved. In addition, the particle diameter of the hydrogen generating material 40 can be confirmed by an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) depending on the diameter.

As the hydrogen generating material 40 in the present invention,
A hydride represented by the general formula MH _4-n ,
A hydride represented by the general formula M (BH ₄ ) _4-n ,
A hydride represented by the general formula M (AlH ₄ ) _4-n ,
(Here, M is an alkali metal of Group 1A of the periodic table, an alkaline earth metal of Group 2A, and n is an integer of 0 to 3),
NH ₃ BH ₃ , and one or a mixture of two or more selected from the group of metal fine particles selected from Al, Fe and Mg are preferable.

Specific examples of the hydride represented by the general formula MH _4-n include LiH, NaH, KH, MgH ₂ , CaH ₂ and AlH _{3, and} are represented by the general formula M (BH ₄ ) _4-n. examples of that hydrides, LiBH ₄ and NaBH ₄ and the like, specific examples of the hydrides of the general formula _{M (AlH 4) 4-n} , include LiAlH ₄ and NaAlH _4.

The hydrogen generating material is particularly preferably one or a mixture of two or more selected from NaBH ₄ , LiBH ₄ and NH ₃ BH ₃ . This is for the reason described in “Mode 3” described later.

  Examples of the fuel retained in the fuel chamber 80 in the present invention include hydrogen, alcohols such as methanol and ethanol, acetals such as dimethoxymethane, carboxylic acids such as formic acid, esters such as methyl formate, and ethers such as dimethyl ether. , Hydrocarbon compounds such as butane and ascorbic acid, and inorganic compounds such as hydrazine, ammonia, sulfite, bisulfite, thiosulfate, dithionite, hypophosphorous acid and phosphorous acid One type or a mixture of two or more types can be exemplified.

  Further, the electrolyte membrane 5, the fuel electrode 4, the air electrode 6, the fuel diffusion layer 3, the fuel electrode conductive layer 2, the air diffusion layer 7 and the air electrode conductive layer 8 in the fuel cell 10 according to the present invention are conventionally used. It is possible to use the material currently used suitably. Further, for the purpose of facilitating handling and reducing the electrical resistance at the interface between the members, it is preferable that the fuel cell is constituted by integrating the members. For example, the air electrode conductive layer 8, the air diffusion layer 7, the air electrode 6, the electrolyte membrane 5, the fuel electrode 4, the fuel diffusion layer 3, and the fuel electrode conductive layer 2 are laminated in this order from below, and this laminate is used as a hot press machine. By using thermocompression bonding at a temperature exceeding the softening temperature or glass transition temperature of the electrolyte in the electrolyte membrane or the catalyst layer in the layer thickness direction, each member becomes a state bonded by chemical bond, anchor effect, adhesive force, etc. Can be integrated.

Examples of the electrolyte membrane 5 include perfluorosulfonic acid electrolyte membranes (Nafion (DuPont), Dow membrane (Dow Chemical), Aciplex (Asahi Kasei), Flemion (Asahi Glass)) and polystyrene. Examples thereof include hydrocarbon electrolyte membranes such as sulfonic acid and sulfonated polyether ether ketone, and examples of inorganic membranes include phosphate glass, cesium hydrogen sulfate, polytungstophosphoric acid, and ammonium polyphosphate. An example of the composite film is a Gore Select film (manufactured by Gore). The electrolyte membrane preferably has a proton conductivity of 10 ⁻⁵ S / cm or more, more preferably a polymer having a proton conductivity of 10 ⁻³ S / cm or more, such as a perfluorosulfonic acid polymer or a hydrocarbon-based polymer. It is desirable to use an electrolyte membrane.

  As the fuel electrode 4 and the air electrode 6, a material including a carrier supporting a catalyst and an electrolyte can be used. Examples of the catalyst used for the fuel electrode 4 and the air electrode 6 include noble metals such as Pt, Ru, Au, Ag, Rh, Pd, Os, Ir, Ni, V, Ti, Co, Mo, Fe, Cu, and Zn. Examples thereof include base metals such as Sn, W, Zr, oxides thereof, carbides, carbonitrides, and carbon. One or a combination of two or more of these materials can be used as a catalyst. The catalyst used for each of the fuel electrode 4 and the air electrode 6 is not necessarily limited to the same type, and different substances can be used.

  The carrier contained in the fuel electrode 4 and the air electrode 6 is preferably made of a carbon material having high electrical conductivity, such as carbon black (specifically, XC72 (manufactured by Vulcan), etc.), ketjen black, carbon Examples include nanotubes and carbon nanohorns. In addition to carbon materials, noble metals such as Pt, Ru, Au, Ag, Rh, Pd, Os, Ir, Ni, V, Ti, Co, Mo, Fe, Cu, Zn, Sn, W, Zr, etc. Base metals, and oxides, carbides, nitrides, and carbonitrides thereof. These materials can be used alone or in combination of two or more as the carrier. Further, a material imparted with proton conductivity to the carrier, specifically, sulfated zirconia, zirconium phosphate, or the like may be used.

  The electrolyte used for the fuel electrode 4 and the air electrode 6 is not particularly limited as long as it is a material having proton conductivity and electrical insulation, but is preferably a solid or gel that is not dissolved by the fuel. Specifically, organic polymers having strong acid groups such as sulfonic acid and phosphoric acid groups and weak acid groups such as carboxyl groups are preferred. Examples of such organic polymers include perfluorocarbon (Nafion (manufactured by DuPont)), carboxyl group-containing perfluorocarbon (Flemion (manufactured by Asahi Kasei)), polystyrene sulfonic acid copolymer, polyvinyl sulfonic acid copolymer, and imidazole (Im). And an ionic liquid (room temperature molten salt) having trifluoromethanesulfonimide (HTFSI), sulfonated imide, 2-acrylamide 2-methylpropanesulfonic acid (AMPS), and the like. In addition, when the above-described carrier imparted with proton conductivity is used, an electrolyte is not necessarily required because the carrier conducts proton conduction.

  The thickness of the fuel electrode 4 and the air electrode 6 is preferably 0.2 mm or less in order to reduce the resistance of proton conduction and the resistance of electron conduction and reduce the diffusion resistance of fuel or air. Moreover, in order to improve the output as a battery, it is necessary to carry | support sufficient catalyst, and it is preferable that it is at least 0.1 micrometer or more.

  The fuel diffusion layer 3 and the air diffusion layer 7 need to be conductive materials to exchange electrons with the fuel electrode 4 and the air electrode 6. For example, carbon materials such as carbon black, Au, Pt, Pd, etc. It is preferable to use noble metals, metals such as Ti, Ta, W, Nb and Cr, nitrides and carbides of these metals, stainless steel, Cu—Cr, Ni—Cr, Ti—Pt alloys and the like. In addition, when using metals with poor corrosion resistance in an acidic atmosphere such as Cu, Ag, Zn, Ni, etc., noble metals and metal materials having corrosion resistance, conductive oxides, conductive nitrides, conductive Conductive carbonitrides such as carbides can be used as the surface coating. By using a material having high corrosion resistance, deterioration of the electrolyte membrane mainly due to elution of metal ions or the like can be suppressed, so that the life of the fuel cell can be extended. The air diffusion layer 7 preferably contains a fluorine-based resin having water repellency such as PTFE (polytetrafluoroethylene) and PVDF (polyvinylidene fluoride) in addition to the above-described materials. With these water-repellent resins, water generated by the power generation of the fuel cell can be quickly discharged from the air diffusion layer 7 to increase the amount of water vapor required in the present invention.

  The shape of the fuel diffusion layer 3 and the air diffusion layer 7 is not particularly limited as long as it has a communication hole capable of supplying fuel or air to the fuel electrode 4 and the air electrode 6. It is preferable to have a hole communicating in a vertical direction with respect to the metal, and examples thereof include foam metal, metal fabric, metal sintered body, carbon paper, carbon cloth, and carbon felt. The porosity of the fuel diffusion layer 3 and the air diffusion layer 7 is preferably 10% or more for reducing the diffusion resistance of fuel or air, 95% or less is preferable for reducing the electric resistance, and is 30% to 85%. More preferably. For the measurement of the porosity, for example, a mercury intrusion method can be used.

  The fuel diffusion layer 3 and the air diffusion layer 7 preferably have a thickness of 10 μm or more in order to supply fuel or air uniformly to the catalyst layer. The thickness direction of the fuel diffusion layer 3 and the air diffusion layer 7 In order to reduce the diffusion resistance of fuel or oxygen to the substrate, the thickness after hot pressing is preferably 1 mm or less, and more preferably 50 μm to 300 μm.

  The fuel electrode conductive layer 2 and the air electrode conductive layer 8 have a function of exchanging electrons with the fuel diffusion layer 3 and the air diffusion layer 7. Materials used for the conductive layer include carbon materials such as graphite, noble metals such as Au, Pt, and Pd, metals such as Ti, Ta, W, Nb, Ni, Al, Cr, Ag, Cu, Zn, and Su, It is preferable to use Si and alloys thereof such as nitrides, carbides, carbonitrides, stainless steel, Cu—Cr, Ni—Cr, Ti—Pt, etc., and Pt, Ti, Au, Ag, Cu, Ni, More preferably, it contains at least one element selected from the group consisting of W. In addition, when using a metal having poor corrosion resistance in an acidic atmosphere such as Cu, Ag, Zn, etc., noble metals and metal materials having corrosion resistance such as Au, Pt, Pd, conductive nitride, conductive Conductive carbide, conductive carbonitride, conductive oxide, etc. can be used as the surface coating. By using a material having high corrosion resistance, deterioration of the electrolyte membrane mainly due to elution of metal ions or the like can be suppressed, so that the life of the fuel cell can be extended. Moreover, since the specific resistance of the fuel electrode conductive layer 2 and the air electrode conductive layer 8 is reduced by including the above elements, the voltage drop due to the electrical resistance of the fuel electrode conductive layer 2 and the air electrode conductive layer 8 is reduced, Higher power generation characteristics can be obtained.

<Configuration of hydrogen generation mechanism and fuel chamber>
2 to 4 are cross-sectional views showing one embodiment of the hydrogen generation mechanism, the hydrogen separation mechanism, and the fuel chamber, respectively, in the present invention. 2 to 4 illustrate a preferred configuration of the hydrogen generation mechanism and the fuel chamber of the present invention. 2 to 4 indicate the internal pressure in the hydrogen generation mechanism and the internal pressure in the fuel chamber, respectively. The “product” in FIGS. 2 to 4 indicates a compound that is generated in the power generation using the fuel previously generated in the fuel chamber or hydrogen generated by the hydrogen generation mechanism, and the “unreacted product” is the fuel. The fuel before being supplied to the battery or the fuel that has not reacted in the fuel cell is shown.

≪Hydrogen generation mechanism and fuel chamber configuration: Form 1≫
This embodiment will be described with reference to FIG. The fuel chamber 81, the hydrogen generation mechanism 31, the hydrogen separation mechanism 21, and the hydrogen generating material 41 in FIG. 2 are as described above. In this embodiment, the hydrogen generating mechanism 31 is provided with the first leak valve 100, and the fuel chamber 81 is provided with the second leak valve 101. The first leak valve 100 has a role of adjusting the internal pressure P1 in the hydrogen generation mechanism 31, and the second leak valve 101 has a role of adjusting the internal pressure P2 in the fuel chamber 81. In FIG. 2, the first leak valve 100 and the second leak valve 101 are provided, but only the first leak valve 100 or only the second leak valve 101 may be provided.

  The internal pressure adjustment method in the first leak valve 100 and the second leak valve 101 is not particularly limited. For example, a pressure relief valve 61B2 (manufactured by IBS Co., Ltd.) and RL3 (manufactured by Swagelok) can be employed.

  The operation of the above-described relief valve is as follows. The valve has a function of releasing a gas and maintaining a constant pressure when an appropriate set stress is applied, for example, a stress in a range of 0.1 MPa to 1.5 MPa. The relief valve does not discharge gas from the hydrogen generation mechanism 31 when the internal pressures P1 and P2 in the hydrogen generation mechanism 31 and the fuel chamber 81 are less than the set stress. However, when the internal pressures P1 and P2 exceed the set stress, the gas is released from the relief valve and the pressure is maintained.

  The internal pressure P1 and the internal pressure P2 can be measured by, for example, a normal pressure gauge (manufactured by Nagano Keiki Co., Ltd.). Further, when a relief valve is used as the first leak valve 100 and the second leak valve 101, it can be regarded as the internal pressure P1 and the internal pressure P2 by reading from the opening / closing pressures of the valves. For example, when a set pressure of 0.5 MPa is set, the valve does not open, and when a set pressure of 0.4 MPa is set, when the valve opens, the internal pressure may be regarded as approximately 0.4 MPa.

  In this embodiment, during the operation of the fuel cell system, the first leak valve 100 and the second leak valve are set such that the relationship between the internal pressure P1 of the hydrogen generation mechanism 31 and the internal pressure P2 of the fuel chamber 81 is P1> P2. 101 and can be adjusted. When the relationship between the internal pressure P1 and the internal pressure P2 is P1> P2, it is preferable because the hydrogen generated by the hydrogen generating mechanism 31 and the air containing water vapor can be easily separated. The separation is facilitated when P1> P2 because the driving force of hydrogen permeation of the hydrogen separation mechanism 21 depends on the differential pressure between P1 and P2, and the hydrogen permeate in proportion to the differential pressure. The flow rate increases.

  The differential pressure between the internal pressure P1 and the internal pressure P2 is preferably 0.1 MPa to 1.0 MPa, and particularly preferably 0.2 MPa to 1.0 MPa. This is because when the differential pressure range between the internal pressure P1 and the internal pressure P2 is within the above-described numerical range, it is easy to separate hydrogen and air containing water vapor. Further, the internal pressure P1 is preferably 0.2 MPa to 1.1 MPa, and the internal pressure P2 is preferably normal pressure (0.1 MPa).

  In this embodiment, the arrangement of the hydrogen generating material 41 in the hydrogen generating mechanism 31 is not particularly limited. Further, the shape of the hydrogen separation mechanism 21 is not particularly limited.

  In the hydrogen generation mechanism 31, when the hydrogen generation material 41 is arranged to form a thin layer in contact with the hydrogen separation mechanism 21, the utilization efficiency of the hydrogen generation material 41 is improved. This is because the pressure of the air containing water vapor introduced into the hydrogen generation mechanism 31 is uniformly applied to the hydrogen generating material 41. In order to improve the hydrogen permeability in the hydrogen separation mechanism 21, it is preferable to increase the surface area of the hydrogen separation mechanism 21 with respect to the fuel chamber 81. Therefore, for example, the hydrogen separation mechanism 21 is arranged in a cylindrical shape. Specifically, a hollow cylindrical wall surface is formed by the hydrogen separation mechanism 21, and the hydrogen generating material 41 is provided inside the wall, and this is provided in the fuel chamber 81. The surface area of the hydrogen separation mechanism 21 can be increased.

  In addition, the heat generated in the hydrogen generation mechanism 31 is transferred to the fuel chamber 81 via the hydrogen separation mechanism 21, and as a result, the power generation efficiency of the fuel cell is improved. According to this embodiment, the hydrogen separation mechanism 21 also serves as a heat supply mechanism.

  The material of the first leak valve 100 and the second leak valve is preferably a material having corrosion resistance in an acidic atmosphere. Specifically, fluoropolymer resins with high corrosion resistance such as PTFE, PVDF, PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), noble metals such as Au, Pt and Pd, Ti, Ta, W It is preferable to use metals such as Nb, Ni, Al, Cr, Ag, Cu, Zn and Su, alloys of C, Si, stainless steel and titanium-platinum, and nitrides and carbides of these metals. Moreover, when using metals, such as Cu, Ag, and Zn, it is preferable to coat with noble metals Au, Ag, Pt, etc. which have higher corrosion resistance than the metal.

≪Hydrogen generation mechanism and fuel chamber configuration: Form 2≫
This embodiment will be described with reference to FIG. The fuel chamber 82, the hydrogen generation mechanism 32, the hydrogen separation mechanism 22, and the hydrogen generating material 42 in FIG. 3 are as described above.

  In the hydrogen generation mechanism 32, when the direction in which air containing water vapor is introduced is upstream and the direction in which the gas in the hydrogen generation mechanism 32 is exhausted is downstream, the arrangement interval of the hydrogen generating material 42 downstream is upstream. It is preferable that it is smaller than the arrangement interval of the hydrogen generating material 42 in FIG. Further, at this time, it is preferable that the particle diameter of the hydrogen generating material 42 arranged becomes smaller from the upstream side to the downstream side.

  In this embodiment, the pressure loss of the gas in the hydrogen generation mechanism 32 increases as it goes downstream in the hydrogen generation mechanism 32. Therefore, the internal pressure of the hydrogen generation mechanism can be increased without providing the leak valve as in the first mode. As a result, the internal pressure P1 of the hydrogen generation mechanism 32 becomes larger than the internal pressure P2 of the fuel chamber 82, so that hydrogen and air can be easily separated. In the case of this structure, the internal pressure P1 and the internal pressure P2 can be controlled without providing a leak valve, which is advantageous for reducing the weight and size of the fuel cell system.

≪Hydrogen generation mechanism and fuel chamber configuration: Form 3≫
This embodiment will be described with reference to FIG. The fuel chamber 83, the hydrogen generation mechanism 33, the hydrogen separation mechanism 23, and the hydrogen generating material 43 in FIG. 4 are as described above.

  In the hydrogen generation mechanism 33, the check valve 103 is connected to an introduction portion (not shown) that uses the specific hydrogen generation material 43 and connects the hydrogen generation mechanism 33 and the air chamber (not shown). Is provided.

The above-mentioned “specific hydrogen generating material 43” is a reaction in which the stoichiometric number of generated hydrogen is larger than the stoichiometric number of water in the air containing water vapor necessary for generating hydrogen from the hydrogen generating material. For example, LiBH ₄ , NaBH ₄ and NH ₃ BH ₃ can be exemplified.

The reaction when LiBH ₄ , NaBH ₄ and NH ₃ BH ₃ are used as the hydrogen generating material 43 is as follows.

LiBH ₄ + 2H ₂ O → LiBO ₂ + 4H ₂
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂
NH ₃ BH ₃ + 2H ₂ O → NH ₄ ⁺ + BO ₂ ⁻ + 3H ₂
As shown above, the stoichiometric number of hydrogen produced is larger than the stoichiometric number of “water” used in the reaction.

  The check valve 103 provided in the introduction mechanism allows water containing water vapor to pass from the air chamber toward the hydrogen generation mechanism 33, but the gas in the hydrogen generation mechanism 33 flows from the hydrogen generation mechanism 33 toward the air chamber. Suppress. When air containing water vapor is introduced into the hydrogen generation mechanism 33, the above-described reaction occurs in the hydrogen generation mechanism 33, and the volume of generated hydrogen becomes larger than the volume of water vapor necessary for the reaction. As a result, the gas in the hydrogen generation mechanism 33 generates a force to flow back to the air chamber through the introduction mechanism, but the check valve 103 makes it difficult for the gas to flow back to the air chamber. Therefore, the internal pressure P1 in the hydrogen generation mechanism 23 increases, and as a result, the internal pressure P1> the internal pressure P2, and separation between hydrogen and air containing water vapor becomes easy.

  Furthermore, heat is generated by hydrolysis or oxidation of the hydrogen generating material in any of the structures 1 to 3 of the hydrogen separation mechanism. Since this heat is transmitted to the fuel chamber via the hydrogen separation mechanism, it is easy to raise the temperature of the fuel chamber. That is, in Embodiments 1 to 3, the hydrogen separation mechanism also serves as a heat supply mechanism that transmits heat generated in the hydrogen generation mechanism to the fuel chamber and supplies it to the fuel cell.

  In addition, the hydrogen generation mechanism and the fuel chamber according to any one of the first to third aspects of the hydrogen separation mechanism described above are connected to the fuel cell, and the hydrogen permeated through the hydrogen separation mechanism results in the fuel of the fuel cell. Supplied to the pole. When fuel is held in advance in the fuel chamber before power generation by the fuel cell, the fuel held in advance and the hydrogen generated from the hydrogen generation mechanism are supplied to the same fuel cell. In order to improve the hydrogen permeation rate in the hydrogen separation mechanism, the fuel previously held in the fuel chamber is preferably a gaseous fuel that is a gas at normal temperature (25 ° C.), and hydrogen or a hydrocarbon fuel having a low boiling point. Examples thereof include DME (dimethyl ether), butane, and ammonia. Here, as the fuel, when a liquid fuel that is liquid at normal temperature (25 ° C.) or a fuel obtained by melting a solid fuel that is solid at normal temperature (25 ° C.) into a liquid is selected, the pressures of internal pressure P1 and internal pressure P2 are selected. It may be difficult to obtain the difference, and it is more preferable to select a gaseous fuel because a sufficient hydrogen permeation rate cannot be obtained. However, liquid fuel can be used depending on the form of the fuel cell system.

  Hereinafter, the present invention will be described in more detail with reference to specific embodiments, but the present invention is not limited thereto.

<Embodiment 1>
FIG. 5 is a cross-sectional view of a surface perpendicular to the layer thickness direction of the fuel cell schematically showing one embodiment of the fuel cell system of the present invention. Hereinafter, a description will be given based on FIG.

  The fuel cell system of the present embodiment has the same basic configuration as the fuel cell system in FIG. However, regarding the configuration of the hydrogen generation mechanism and the fuel chamber, any one of the above-described forms 1 to 3 may be used.

  When performing the hydrogen separation shown in FIG. 4, the valve 60 that adjusts the amount of air containing water vapor introduced into the hydrogen generation mechanism 30 is closer to the air chamber 50 than the check valve 103 in FIG. 4 described above. It is preferable to be formed. When the valve 60 and the check valve 103 are arranged in reverse, the hydrogen generation mechanism 30 is pressurized when hydrogen is generated by the hydrogen generation mechanism 30, so that the structure and material of the valve 60 can withstand the pressure increase. This is because it becomes necessary to do this.

<Embodiment 2>
FIG. 6 is a cross-sectional view of a surface perpendicular to the layer thickness direction of the fuel cell schematically showing one embodiment of the fuel cell system of the present invention. Hereinafter, a description will be given with reference to FIG.

  The basic configuration of the fuel cell system of the present embodiment is the same as that of the fuel cell system of the first embodiment. And about the structure of a hydrogen production | generation mechanism and a fuel chamber, you may use any of the form 1 to form 3 mentioned above.

  The present embodiment is different from the first embodiment in that a gas-liquid separation membrane 104 is further provided in the fuel chamber 80. The gas-liquid separation membrane 104 is preferably provided so as to bisect the fuel chamber 80 in parallel to the fuel chamber 80 in the stacking direction of the fuel cell 10. The gas-liquid separation membrane 104 mainly refers to a membrane having the property of impervious to liquids composed of fuel and its aqueous solution and the property of permeable to gas (hydrogen) from the hydrogen separation mechanism 20. By providing the gas-liquid separation membrane 104 in the fuel chamber 80, the fuel in the fuel chamber 80 and the hydrogen separation mechanism 20 are prevented from coming into contact with each other, and the hydrogen permeation rate in the hydrogen separation mechanism 20 is hardly hindered. In addition, when the by-product generated by the power generation of the fuel or the fuel cell is acidic, these do not directly touch the hydrogen separation mechanism 20, so that the effect of suppressing the corrosion deterioration of the metal contained in the hydrogen separation mechanism 20 is obtained. It is done. In the present embodiment, liquid fuel can be selected as the fuel previously held in the fuel chamber. This is because the hydrogen generated in the hydrogen generation mechanism 30 reaches the fuel chamber 80, but the liquid fuel is not in contact with the hydrogen separation mechanism 20 by providing the gas-liquid separation membrane 104. Further, the liquid fuel has a high hydrogen content per volume, and the energy density of the fuel is high.

  The liquid fuel is not particularly limited, but is preferably a fuel that is liquid at room temperature (25 ° C.) or a fuel obtained by dissolving a solid fuel that is solid at room temperature (25 ° C.) in a liquid such as water. . Specific examples of the liquid fuel include alcohols such as methanol and ethanol, acetals such as dimethoxymethane, carboxylic acids such as formic acid, esters such as methyl formate, ascorbic acid and hydrazine.

  The gas-liquid separation membrane 104 is preferably a porous material, which will be described later. Further, when the by-product generated by the power generation of the fuel or the fuel cell is acidic, it is preferable to use a material having high corrosion resistance. Specifically, fluorine resin such as PTFE and PVDF, carbon black (specifically, XC72 (manufactured by Vulcan), etc.), ketjen black, amorphous carbon, carbon nanotube, carbon nanohorn, and other inclusions A porous layer made of a mixture into which is introduced can be exemplified. Since the above-described carbon-based inclusions have a high bulk density, a gap is generated between the materials, and a porous layer can be formed. And it is preferable that the gas-liquid separation membrane 104 is 10-500 micrometers thick.

<Embodiment 3>
FIG. 7 is a cross-sectional view of a surface perpendicular to the layer thickness direction of the fuel cell schematically showing one embodiment of the fuel cell system of the present invention. Hereinafter, a description will be given with reference to FIG.

  Hereinafter, although the fuel cell system incorporating the first fuel cell and the second fuel cell will be described, these configurations are the same as the above-described fuel cell.

  The fuel cell system of the present embodiment includes a first fuel cell 11, a second fuel cell 12, a first fuel chamber 84, a second fuel chamber 85, a first air chamber 54, and a second air chamber 55. The first introduction mechanism 91, the second introduction mechanism 92, the first valve 61, the second valve 62, and the hydrogen generation mechanism 34 are basically provided. The hydrogen generating mechanism 34 includes a hydrogen generating material 44, the first fuel chamber 84 and the hydrogen generating mechanism 34 are separated by a partition 110, and the second fuel chamber 85 and the hydrogen generating mechanism 34 are separated from the hydrogen separating mechanism 24. Separated by

  The first fuel chamber 84 and the first air chamber 54 are adjacent to the first fuel cell 11, and the second fuel chamber 85 and the second air chamber 55 are adjacent to the second fuel cell 12. The first fuel chamber 84 and the second fuel chamber 85 are separated by the hydrogen separation mechanism 24 and the partition 110, and the hydrogen generation mechanism 34 is formed by the hydrogen separation mechanism 24 and the partition 110. The partition 110 preferably completely blocks between the hydrogen generation mechanism 34 and the first fuel chamber 84.

  The air containing water vapor in the first air chamber 54 is introduced into the hydrogen generation mechanism 34 by the introduction mechanism 91, and the air containing water vapor in the second air chamber 55 is introduced into the hydrogen generation mechanism 34 by the introduction mechanism 92. . The amount of air containing water vapor introduced by the introduction mechanism 91 is controlled by the first valve 61, and the amount of air containing water vapor introduced by the introduction mechanism 92 is controlled by the second valve 62.

  It is preferable that fuel is held in the first fuel chamber 84 in advance. The hydrogen generation mechanism 34 and the first fuel chamber 84 are separated from each other by the partition 110, and the hydrogen generated by the hydrogen generation mechanism 34 is not supplied to the first fuel cell 11, and the fuel is supplied to the first fuel chamber 84. This is because the first fuel cell 11 does not operate unless is held.

  The fuel is preferably held in advance in the second fuel chamber 85, but it is not necessary to hold the fuel in the second fuel chamber 85 as long as the fuel is previously held in the first fuel chamber 84. This is because when the fuel is previously held in the first fuel chamber 84, the first fuel cell 11 is operated, air containing water vapor is accumulated in the first air chamber 54, and hydrogen is generated by the introduction mechanism 91. Air containing the water vapor is introduced into the mechanism 34. At this time, hydrogen is generated in the hydrogen generation mechanism 34, and the generated hydrogen is supplied to the second fuel chamber 85 through the hydrogen separation mechanism 24. Then, since the 2nd fuel cell 12 starts electric power generation, it is because a continuous driving | operation is possible.

  In the first embodiment and the second embodiment, when the fuel previously held in the fuel chamber 80 is other than hydrogen, the fuel electrode is formed by the fuel held in advance and a reaction intermediate generated in the oxidation reaction of the fuel. There is a possibility that sufficient space for the reaction of hydrogen oxidation in 4 is not obtained. Only at this time, there is a possibility that a problem of reduction in power generation efficiency in the fuel cell may occur. In the present embodiment, in order to solve the above-described problem, a fuel cell system with higher output can be provided.

  For example, even when the fuel previously held in the first fuel chamber 84 is other than hydrogen, the fuel in the first fuel chamber 84 and the hydrogen generated by the hydrogen generation mechanism 34 are not mixed with each other by the partition 110, and the above-described first The fuel and hydrogen held in the first fuel chamber 84 are separately supplied to the first fuel cell 11 or the second fuel cell 12. Therefore, according to the present embodiment, hydrogen oxidation in the first fuel chamber 84 and the second fuel chamber 85 is not inhibited, and as a result, a high output can be obtained from the first fuel cell 11 and the second fuel cell 12.

  Further, the hydrogen generated by the hydrogen generating mechanism 34 is not supplied to the first fuel chamber 84, but the reaction heat generated by the hydrogen generating mechanism 34 is transferred through the partition 110. That is, the partition 110 also serves as a heat supply mechanism that supplies heat to the first fuel cell 11. The hydrogen generation mechanism 34 also functions as a heat supply mechanism that supplies heat to the second fuel cell 12. Due to the heat supply mechanism, the power generation efficiency of the first fuel cell 11 and the second fuel cell 12 is improved.

  The partition 110 also serves as a heat supply mechanism that transfers heat to the first fuel chamber 84 and supplies heat to the first fuel cell 11. A material having excellent heat conductivity and corrosion resistance is preferable so that the reaction heat of hydrogen generation in the hydrogen generation mechanism 34 is easily transferred to the first fuel chamber 84. By using a material having high corrosion resistance, deterioration of the electrolyte membrane mainly due to elution of metal ions or the like can be suppressed, so that the life of the fuel cell can be extended. Specifically, the partition 110 includes noble metals such as Au, Pt and Pd, metals such as C, Ti, Ta, W, Nb, Ni, Al, Cr, Ag, Cu, Zn and Su, Si, and further stainless steel and titanium. -It is preferable to use platinum alloys and alloys of these metals such as nitrides and carbides. Further, when using a metal such as Cu, Ag, or Zn, the partition 110 can be used by coating with a noble metal having corrosion resistance such as Au, Ag, or Pt.

<Embodiment 4>
FIG. 8 is a cross-sectional view of a surface perpendicular to the layer thickness direction of the fuel cell schematically showing one embodiment of the fuel cell system of the present invention. Hereinafter, a description will be given based on FIG.

  The fuel cell system of the present embodiment includes a first fuel cell 13, a second fuel cell 14, a first fuel chamber 86, a second fuel chamber 87, an air chamber 56, an introduction mechanism 93, and hydrogen generation. A mechanism 35 is basically provided. The hydrogen generating mechanism 35 is provided with a hydrogen generating material 45, and the second fuel chamber 87 and the hydrogen generating mechanism 34 are separated by a hydrogen separation mechanism 25 provided in parallel with the layer of the second fuel cell 14. The first fuel chamber 86 is separated from the hydrogen generation mechanism 35 and the second fuel chamber 87 by a partition 111 perpendicular to the layer thickness direction of the first fuel cell 13.

  The first fuel chamber 86 and the air chamber 56 are adjacent to the first fuel cell 13, and the second fuel chamber 87 and the air chamber 56 are adjacent to the second fuel cell 12. Further, the first fuel cell 13 and the second fuel cell 14 have the same layer thickness direction.

  The first fuel cell 13 and the second fuel cell 14 share an air chamber 56. Therefore, air containing water vapor generated from the air electrode in the first fuel cell 13 and the second fuel cell 14 is accumulated in the air chamber 56 and is introduced into the hydrogen generation mechanism 35 by the introduction mechanism 93. The amount of air containing the water vapor can be controlled by the valve 63 to be introduced into the hydrogen generation mechanism 45.

  It is preferable that fuel is held in the first fuel chamber 86 in advance. The hydrogen generation mechanism 35 and the first fuel chamber 86 are separated by a partition 111, and the hydrogen generated by the hydrogen generation mechanism 34 is not supplied to the first fuel chamber, and fuel is supplied to the first fuel chamber 84. This is because the first fuel cell 11 does not operate unless it is held.

  Although it is preferable that the fuel is held in the second fuel chamber 87 in advance, it is not necessary to hold the fuel in the second fuel chamber 87 if the fuel is held in the first fuel chamber 86 in advance. This is because when the fuel is previously held in the first fuel chamber 86, the first fuel cell 13 is operated, air containing water vapor is accumulated in the air chamber 56, and the hydrogen generation mechanism 35 is introduced by the introduction mechanism 93. The air containing the water vapor is introduced. At this time, hydrogen is generated in the hydrogen generation mechanism 35, and the generated hydrogen is supplied to the second fuel chamber 87 through the hydrogen separation mechanism 25. Then, since the second fuel cell 14 starts power generation, continuous operation is possible.

  In the first and second embodiments, when the fuel previously held in the fuel chamber 80 is other than hydrogen, the hydrogen in the fuel electrode 4 is caused by the fuel held in advance and a reaction intermediate generated in the oxidation reaction of the fuel. There is a possibility that sufficient space for oxidation reaction may not be obtained. Only at this time, there is a possibility that a problem of reduction in power generation efficiency in the fuel cell may occur. In the present embodiment, in order to solve the above-described problem, a fuel cell system with higher output can be provided.

  Furthermore, in the present embodiment, it is possible to make the fuel cell system thinner in the layer thickness direction than in the third embodiment. Since the air chamber 56 can be shared by the first fuel cell 13 and the second fuel cell 14, the pressure loss for supplying air can be minimized, and the power consumption of the air supply fan 70 is reduced. can do. Further, it is not necessary to provide an introduction mechanism from each of the first air chamber and the second air chamber to the hydrogen generation mechanism as in the third embodiment, and an introduction mechanism 93 from one air chamber 56 to the hydrogen generation mechanism 35 is provided. Can be provided. Therefore, the structure of the fuel cell system becomes simple, and the amount of air containing water vapor introduced by the valve 63 can be easily controlled. It is also possible to share the electrolyte membrane of the first fuel cell 13 and the second fuel cell 14.

  However, since the contact area between the partition 111 and the first fuel chamber 86 is smaller than in the third embodiment, the heat generated in the hydrogen generation mechanism 35 is not easily transmitted to the first fuel chamber 86. The amount of heat supplied to the first fuel cell 13 by the partition 111 as a heat supply mechanism is lower than that in the third embodiment. Note that heat is transferred to the second fuel cell 14 through the hydrogen separation mechanism 25 as in the third embodiment, and the power generation efficiency is improved.

  The partition 111 between the first fuel chamber 86 and the hydrogen generation mechanism 35 is preferably made of the same material as in the third embodiment.

  Embodiments 1 to 4 described above merely exemplify the minimum configuration, and the number of hydrogen generation mechanisms and the number of fuel cells to be arranged are not particularly limited as long as the number is the minimum number or more. For example, in the first and second embodiments, a configuration in which one hydrogen generation mechanism is provided for one fuel cell is taken as an example. However, a fuel cell having a plurality of fuel cells for one hydrogen generation mechanism. It may be a system. Further, the fuel cell system may be configured to include a plurality of hydrogen generation mechanisms and fuel cells. The third embodiment is composed of one hydrogen generation mechanism and two fuel cells. However, a number of fuel cells that use hydrogen obtained from the hydrogen generation mechanism for power generation reaction are arranged for one hydrogen generation mechanism, and steam is supplied. It is also possible to construct a fuel cell system with an increased supply of air.

  In other words, a fuel cell is provided with a plurality of fuel cells, and a partition that separates hydrogen generated by the hydrogen generation mechanism and fuel in the fuel chamber is installed, and the partition selects a material that does not allow hydrogen to pass. It is possible to appropriately construct a fuel cell system including a fuel cell to be supplied and a fuel cell to which hydrogen generated by a hydrogen generation mechanism and fuel in a fuel chamber are supplied. The fuel cell to which the fuel in the fuel chamber is supplied and the fuel cell to which the hydrogen generated by the hydrogen generation mechanism and the fuel in the fuel chamber are supplied undergo a power generation reaction separately.

  In order to secure a desired output voltage, in the fuel cell systems of the first to fourth embodiments, the fuel cell systems can be connected in series or in parallel. Thus, the fuel cell system of Embodiment 4 can be constructed by combining them in series or in parallel. For example, in the third embodiment, the first fuel cell 1 and the second fuel cell 2 are arranged in the layer thickness direction, and in the fourth embodiment, the first fuel cell and the second fuel cell are arranged perpendicular to the layer thickness direction. However, a combination of these may be used to arrange a plurality of fuel cells in each of the layer thickness direction and the direction perpendicular to the layer thickness direction.

<Embodiment 5>
FIG. 9 is a schematic diagram showing a preferred example of an electronic apparatus equipped with the fuel cell system according to the present invention. Hereinafter, a description will be given with reference to FIG.

  The fuel cell system 200 of the present invention can be suitably applied to electronic devices, in particular, portable electronic devices such as mobile devices, since it is lightweight, small and capable of obtaining high output. The electronic device shown in FIG. 9 is a mobile phone, but other electronic devices include, for example, an electronic notebook, portable game device, mobile TV device, handy terminal, PDA, mobile DVD player, notebook computer, video device, and camera. Examples include equipment, ubiquitous equipment, and mobile generators.

  In the fuel cell system 200, it is preferable that a plurality of fuel cell systems having the same configuration as the fuel cell systems shown in FIGS. 5 to 8 are electrically connected in series so that the extraction voltage is about 1 to 4V.

  The fuel cell system 200 mounted on the electronic device is connected to a component (not shown) such as a DC / DC converter or a capacitor that supplements instantaneous power, which is converted into a voltage suitable for the electronic device, and connected to the electronic device. can do. A power source other than a fuel cell such as a secondary battery can be provided together with the fuel cell as an auxiliary power source for starting up the electronic device or a power source for covering the maximum output.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a perspective view schematically showing an embodiment of a fuel cell system of the present invention. It is sectional drawing which shows one form of the hydrogen production | generation mechanism in this invention, a hydrogen separation mechanism, and a fuel chamber. It is sectional drawing which shows one form of the hydrogen production | generation mechanism in this invention, a hydrogen separation mechanism, and a fuel chamber. It is sectional drawing which shows one form of the hydrogen production | generation mechanism in this invention, a hydrogen separation mechanism, and a fuel chamber. 1 is a cross-sectional view of a surface perpendicular to a layer thickness direction of a fuel cell schematically showing one embodiment of a fuel cell system of the present invention. 1 is a cross-sectional view of a surface perpendicular to a layer thickness direction of a fuel cell schematically showing one embodiment of a fuel cell system of the present invention. 1 is a cross-sectional view of a surface perpendicular to a layer thickness direction of a fuel cell schematically showing one embodiment of a fuel cell system of the present invention. 1 is a cross-sectional view of a surface perpendicular to a layer thickness direction of a fuel cell schematically showing one embodiment of a fuel cell system of the present invention. It is the schematic which shows a preferable example of the electronic device provided with the fuel cell system in this invention.

Explanation of symbols

  2 Fuel electrode conductive layer, 3 Fuel diffusion layer, 4 Fuel electrode, 5 Electrolyte membrane, 6 Air electrode, 7 Air diffusion layer, 8 Air electrode conductive layer, 10 Fuel cell, 11, 13 First fuel cell, 12, 14 First 2 fuel cell, 20, 21, 22, 23, 24, 25 Hydrogen separation mechanism, 30, 31, 32, 33, 34, 35 Hydrogen generation mechanism, 40, 41, 42, 43, 44, 45 Hydrogen generating material, 50 , 56 Air chamber, 54 First air chamber, 55 Second air chamber, 60, 63 valve, 61 First valve, 62 Second valve, 70 Air supply fan, 80, 81, 82, 83 Fuel chamber, 84, 86 First fuel chamber, 85, 87 Second fuel chamber, 90, 93 introduction mechanism, 91 first introduction mechanism, 92 second introduction mechanism, 100 first leak valve, 101 second leak valve, 103 check valve, 104 air Liquid separation membrane, 110, 111 finish Ri, 200 fuel cell system.

Claims (20)

A fuel cell having an electrolyte membrane, a fuel electrode formed on one surface of the electrolyte membrane, and an air electrode formed on the other surface of the electrolyte membrane;
An air chamber for storing air containing water vapor generated at the air electrode by a power generation reaction of the fuel cell;
A fuel chamber for holding fuel;
A hydrogen generating mechanism for generating hydrogen by reacting the air containing water vapor with a hydrogen generating material;
A hydrogen separation mechanism interposed between the fuel chamber and the hydrogen generation mechanism, for separating hydrogen from the hydrogen generation mechanism and supplying the hydrogen to the fuel chamber;
An introduction mechanism for introducing air containing water vapor from the air chamber into the hydrogen generation mechanism;
A fuel cell system comprising:   2. The fuel cell system according to claim 1, further comprising a heat supply mechanism that supplies heat generated by hydrolysis or oxidation reaction of the hydrogen generating material in the hydrogen generation mechanism to the fuel cell. The fuel cell system according to claim 1, wherein the introduction mechanism includes a valve that adjusts an amount of water vapor introduced into the hydrogen generation mechanism.   The fuel cell system according to claim 1, further comprising an air supply fan.   The fuel cell system according to any one of claims 1 to 4, wherein an internal pressure P1 in the hydrogen generation mechanism is greater than an internal pressure P2 in the fuel chamber.   The fuel cell system according to any one of claims 1 to 5, wherein a leak valve for adjusting the pressures of the internal pressure P1 and the internal pressure P2 is provided in at least one of the hydrogen generation mechanism and the fuel chamber. The arrangement of the hydrogen generating material in the hydrogen generation mechanism is as follows:
The fuel cell system according to any one of claims 1 to 6, wherein a gap between the hydrogen generating materials is arranged smaller toward the downstream side than the upstream side where the air containing the water vapor is introduced. In order to adjust the internal pressure P1 and the internal pressure P2, the hydrogen generating material has a hydrogen generating material in which the stoichiometric number of generated hydrogen is larger than the stoichiometric number of water vapor necessary for generating hydrogen. ,
The fuel cell system according to any one of claims 1 to 7, wherein a check valve is provided between the air chamber and the hydrogen generation mechanism. The hydrogen generating material is
A hydride represented by the general formula MH _4-n ,
A hydride represented by the general formula M (BH ₄ ) _4-n ,
A hydride represented by the general formula M (AlH ₄ ) _4-n ,
(Here, M is an alkali metal of Group 1A of the periodic table, an alkaline earth metal of Group 2A, and n is an integer of 0 to 3),
NH ₃ BH ₃ ,
And
The fuel cell system according to any one of claims 1 to 8, which is one or a mixture of two or more selected from the group of metal fine particles selected from Al, Fe and Mg. The hydrogen generating material is
_{LiH, NaH, KH, MgH 2} , CaH 2, AlH 3, LiBH 4, NaBH 4, LiAlH 4 and NaAlH ₄
The fuel cell system according to claim 9, which is one or more compounds selected from the group consisting of: The fuel cell system according to claim 8 or 9, wherein the hydrogen generating material is one or a mixture of two or more selected from NaBH ₄ , LiBH ₄ and NH ₃ BH ₃ . The hydrogen separation mechanism is
A polymer membrane made of polyimide or polysulfone,
An inorganic porous film made of porous ceramics, and
An alloy film in which palladium or a palladium alloy is coated on the surface of a metal support made of niobium, tantalum or vanadium, or an inorganic porous support made of porous glass, porous ceramics or porous aluminum oxide,
The fuel cell system according to claim 1, wherein the fuel cell system is selected from the group consisting of:   The fuel held in the fuel chamber is methanol, ethanol, dimethoxymethane, formic acid, methyl formate, dimethyl ether, butane, ascorbic acid, hydrazine, ammonia, sulfite, bisulfite, thiosulfate, dithionite, hyposulfite. The fuel cell system according to claim 1, which is one or a mixture of two or more selected from phosphoric acid and phosphorous acid.   The fuel cell system according to claim 13, wherein the fuel held in the fuel chamber is a gaseous fuel.   The fuel cell system according to claim 14, wherein the gaseous fuel is at least one selected from hydrogen, dimethyl ether, butane, and ammonia. The fuel is a liquid fuel or a solid fuel dissolved in a liquid,
The fuel cell system according to claim 13, which is at least one selected from methanol, ethanol, dimethoxymethane, formic acid, methyl formate, ascorbic acid and hydrazine.   The fuel cell system according to any one of claims 1 to 16, further comprising a gas-liquid separation membrane in the fuel chamber.   The fuel cell system according to claim 17, wherein the gas-liquid separation membrane is a porous layer. Comprising a plurality of the fuel cells;
Having a partition separating hydrogen generated by the hydrogen generation mechanism and fuel in the fuel chamber;
The fuel cell supplied with fuel in the fuel chamber;
The fuel cell system according to any one of claims 1 to 18, further comprising the fuel cell to which hydrogen generated by the hydrogen generation mechanism and fuel in the fuel chamber are supplied.   An electronic device comprising the fuel cell system according to any one of claims 1 to 19.

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