JP2007317496A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system which does not require power to supply water and has a high energy efficiency. <P>SOLUTION: The fuel cell power generation system is provided with a fuel cell 100 including a positive electrode 11 to reduce oxygen, a negative electrode 12 to oxidize hydrogen, and a solid electrolyte membrane 13 arranged between the positive electrode 11 and the negative electrode 12 and a hydrogen generating device 200 which includes a hydrogen generating container 21 housing a hydrogen generating material 23 and a water supply container 22 housing water 27 and generates hydrogen by making react the hydrogen generating material 23 and the water 27. The negative electrode 12 and the hydrogen generating container 21 are connected by a hydrogen supply pipe 24, the water supply container 22 and the hydrogen generating container 21 are connected by water supply pipes 28a, 28b, and internal pressure of the water supply container 22 is maintained by atmospheric pressure. When the inner pressure of the hydrogen generating container 21 becomes to have a negative pressure than the atmospheric pressure, the water 27 is supplied from the water supply container 22 to the hydrogen generating container 21 by this negative pressure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system including a fuel cell and a hydrogen generator using a hydrogen generating material that reacts with water to generate hydrogen.

  In recent years, with the widespread use of cordless devices such as personal computers and mobile phones, the battery that is the power source is increasingly required to be smaller and have higher capacity. Currently, lithium ion secondary batteries have been put into practical use as batteries that have high energy density and can be reduced in size and weight, and demand for portable power sources is increasing. However, this lithium ion secondary battery has a problem that it cannot guarantee a sufficient continuous use time for some cordless devices.

  In order to solve the above problems, for example, development of fuel cells such as polymer electrolyte fuel cells (PEFC) has been promoted. The fuel cell can be used continuously if fuel and oxygen are supplied. A PEFC that uses a solid polymer electrolyte as an electrolyte, oxygen in the air as a positive electrode active material, and fuel as a negative electrode active material has attracted attention as a battery having a higher energy density than a lithium ion secondary battery.

  There are several candidates for fuels used in PEFC, but each fuel has technical problems. A direct methanol fuel cell (DMFC) that uses methanol as a fuel and reacts methanol with a direct electrode is a battery that can be easily downsized, and is expected as a portable power source in the future. However, DMFC has a problem that the voltage is lowered due to the crossover of the negative electrode methanol passing through the solid electrolyte and reaching the positive electrode, and a high energy density cannot be obtained. On the other hand, as a fuel cell using hydrogen as a fuel, for example, a battery using a high-pressure tank storing hydrogen or a hydrogen storage alloy tank has been put into practical use. However, a battery using such a tank is not suitable for a portable power source because its volume and mass increase and its energy density decreases. A battery using a hydrocarbon-based fuel as a fuel includes a battery using a reforming apparatus that reforms the fuel to extract hydrogen. However, this type of battery is not suitable for a portable power source because it needs to supply heat to the reformer or insulate the reformer.

Under such circumstances, as a method for producing hydrogen as a fuel source of a fuel cell, a method of generating hydrogen by decomposing water by a chemical reaction between water and aluminum, calcium oxide or the like at room temperature has been proposed ( For example, see Patent Document 1.)
JP 2004-231466 A

  According to the method described in Patent Document 1, hydrogen is generated by introducing a predetermined amount of water into aluminum and calcium oxide at a time, but in this case, necessary hydrogen is generated according to the power generation amount of the fuel cell. It cannot be supplied each time. In order to generate the necessary hydrogen each time according to the power generation amount of the fuel cell, it is necessary to supply water in a timely manner. However, Patent Document 1 proposes power such as a pump as water supply means. . However, when a pump or the like is used as a means for supplying water, not only power for driving the pump is required, but the entire apparatus becomes large, and it is not suitable as a portable power source in terms of both energy density and compactness. .

  The present invention relates to a fuel cell power generation system comprising a fuel cell and a hydrogen generator using a hydrogen generating material that reacts with water to generate hydrogen. A power generation system is provided.

  A fuel cell power generation system according to the present invention includes a fuel cell including a positive electrode that reduces oxygen, a negative electrode that oxidizes hydrogen, and a solid electrolyte disposed between the positive electrode and the negative electrode, and a hydrogen generating material. A fuel cell power generation system including a hydrogen generation device that generates hydrogen by reacting the hydrogen generation material and the water, the hydrogen generation container including a water supply container containing water The negative electrode and the hydrogen generation container are connected by a fuel supply flow path, and the water supply container and the hydrogen generation container are connected by a water supply flow path, and the internal pressure of the water supply container is maintained at atmospheric pressure. When the internal pressure of the hydrogen generation container becomes negative than atmospheric pressure, the water is supplied from the water supply container to the hydrogen generation container by the negative pressure.

  According to the present invention, in a fuel cell power generation system including a fuel cell and a hydrogen generator using a hydrogen generating material that reacts with water to generate hydrogen, the power for supplying water is unnecessary and the fuel cell has high energy efficiency. A power generation system can be provided.

  The fuel cell power generation system of the present invention includes a fuel cell and a hydrogen generator. The fuel cell includes a positive electrode that reduces oxygen, a negative electrode that oxidizes hydrogen, and a solid electrolyte disposed between the positive electrode and the negative electrode. In addition, the hydrogen generation device includes a hydrogen generation container containing a hydrogen generation material and a water supply container containing water, and can generate hydrogen when the hydrogen generation material and water react. Further, the negative electrode of the fuel cell and the hydrogen generation container of the hydrogen generation device are airtightly connected by a fuel supply flow path, and the water supply container and the hydrogen generation container of the hydrogen generation apparatus are airtightly connected by a water supply flow path. The internal pressure of the water supply container is maintained at atmospheric pressure.

  In the fuel cell power generation system of the present invention, when the fuel cell consumes hydrogen by power generation, the internal pressure of the hydrogen generation container becomes smaller than atmospheric pressure, that is, the internal pressure of the hydrogen generation container is maintained at atmospheric pressure. When the internal pressure of the water supply container is negative, water can be supplied from the water supply container to the hydrogen generation container by the negative pressure. Thereby, even if there is no power of a pump or the like, necessary hydrogen can be generated each time according to the power generation amount of the fuel cell, so that a fuel cell power generation system with high energy efficiency can be provided.

  The means for maintaining the internal pressure of the water supply container at atmospheric pressure is not particularly limited, but when the internal pressure of the water supply container is reduced due to the supply of water by providing the air supply opening in the water supply container, The air can be taken in, and the internal pressure of the water supply container can be maintained at atmospheric pressure.

  In addition, by forming the water supply container from a material that can be deformed by atmospheric pressure, the water supply container is compressed by atmospheric pressure when the internal pressure of the water supply container decreases due to the supply of water, and the volume of the water supply container And the internal pressure of the water supply container can be maintained at atmospheric pressure.

  The water supply channel preferably includes a backflow prevention valve. Thereby, it can prevent that the water supplied to the hydrogen generation container flows backward.

  The water supply channel preferably includes a flow rate control unit. Even if the reaction between the hydrogen generating material and water starts, if the supply amount of water is excessive, the reaction temperature may decrease and the reaction rate may decrease. Conversely, if the supply amount of water is too low, the reaction may occur. This is because it is preferable to adjust the amount of water supplied because the efficiency may decrease.

  The fuel supply channel preferably includes a pressure release valve. This is to prevent destruction of the apparatus when the reaction rate between the hydrogen generating material and water increases and hydrogen is excessively generated to increase the pressure in the fuel cell power generation system.

  The air introduction port preferably includes a gas-liquid separation membrane. Thereby, when taking in air | atmosphere from an air introduction port, mixing of the foreign material in air | atmosphere can be prevented.

  The hydrogen generating material is not particularly limited as long as it is a material capable of generating hydrogen by reacting with water, but is selected from the group consisting of aluminum, silicon, zinc, magnesium and alloys mainly composed of these elements. It preferably contains at least one hydrogen generating material. This is because hydrogen can be generated by reacting with water at least during heating.

  Embodiments of a fuel cell power generation system according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a conceptual diagram showing an example of a fuel cell power generation system of the present invention. In FIG. 1, the fuel cell power generation system of the present embodiment includes a fuel cell 100 and a hydrogen generator 200.

  The negative electrode 12 of the fuel cell 100 and the hydrogen generation container 21 (described later) of the hydrogen generator 200 are connected in an airtight state via a hydrogen supply pipe 24 serving as a fuel supply flow path. Here, the connection in an airtight state means that when the hydrogen supply pipe 24 communicates with the negative electrode 12 and the water inlet 21b of the hydrogen generation container 21 is sealed, the hydrogen generation container 21 and the hydrogen supply pipe 24 are connected. This means that the internal pressure can be maintained at a pressure lower than atmospheric pressure.

  Further, the water supply container 22 and the hydrogen generation container 21 of the hydrogen generator 200 are connected via water supply pipes 28a and 28b serving as water supply channels.

  Furthermore, the water supply container 22 is provided with an air inlet 22b, and the internal pressure of the water supply container 22 is maintained at atmospheric pressure. Accordingly, when the fuel cell 100 consumes hydrogen by power generation, the internal pressure of the hydrogen generation container 21 becomes smaller than the atmospheric pressure, that is, the water supply container in which the internal pressure of the hydrogen generation container 21 is maintained at the atmospheric pressure. When the internal pressure of the pressure 22 becomes negative, the water 27 can be supplied from the water supply container 22 to the hydrogen generation container 21 through the water supply pipes 28a and 28b. Thereby, even if there is no power of a pump or the like, necessary hydrogen can be generated each time according to the power generation amount of the fuel cell 100, so that a fuel cell power generation system with high energy efficiency can be provided.

  The fuel cell 100 includes a positive electrode 11 that reduces oxygen, a negative electrode 12 that oxidizes hydrogen, and a solid electrolyte membrane 13 disposed between the positive electrode 11 and the negative electrode 12, and includes the positive electrode 11, the negative electrode 12, and the solid electrolyte membrane. 13 are laminated together to form the membrane electrode assembly 10.

  The positive electrode 11 is not particularly limited as long as it is generally used as a positive electrode of a fuel cell, but in this embodiment, the positive electrode catalyst layer 11a and the positive electrode diffusion layer 11b are laminated. The positive electrode catalyst layer 11a can be formed using, for example, a conductive material carrying a catalyst. As the catalyst, for example, platinum fine particles, alloy fine particles of platinum and at least one kind of metal selected from iron, nickel, cobalt, tin, ruthenium and gold can be used. As the conductive material, a carbon material is mainly used. For example, carbon black, activated carbon, carbon nanotube, carbon nanohorn, or the like can be used. In general, catalyst-supporting carbon in which the catalyst is dispersed and supported on the surface of a conductive material is used. Further, the positive electrode diffusion layer 11b can be formed of a porous electron conductive material, for example, a porous carbon material.

  The negative electrode 12 is not particularly limited as long as it is generally used as a negative electrode of a fuel cell, but in the present embodiment, the negative electrode catalyst layer 12a and the negative electrode diffusion layer 12b are laminated. The negative electrode catalyst layer 12a can be formed using, for example, a conductive material carrying a catalyst. Examples of the catalyst include platinum fine particles, ruthenium, indium, iridium, tin, iron, titanium, gold, silver, chromium, silicon, zinc, manganese, molybdenum, tungsten, rhenium, aluminum, lead, palladium, and osmium. Alloy fine particles of at least one kind of metal and platinum can be used. As the conductive material, the same material as the conductive material of the positive electrode catalyst layer 11a described above can be used. The negative electrode diffusion layer 12b can be formed from a porous electron conductive material, for example, using a porous carbon material.

The solid electrolyte membrane 13 is not particularly limited by its material or configuration as long as it is generally used as an electrolyte of a fuel cell, and is disposed between the positive electrode 11 and the negative electrode 12 and can transport protons. It can be formed of a material having no electron conductivity. For example, polyperfluorosulfonic acid resin film, sulfonated polyether sulfonic acid resin film, sulfonated polyimide resin film, sulfuric acid-doped polybenzimidazole film, phosphoric acid-doped SiO ₂ which is a solid electrolyte, polymer and phosphoric acid-doped SiO ₂ A hybrid of the above, a gel electrolyte in which an acidic solution is impregnated with a polymer and an oxide, and the like can be used.

  A positive electrode current collector plate 14 made of a conductive material is disposed on the surface of the membrane electrode assembly 10 on the positive electrode diffusion layer 11b side. The positive electrode current collector plate 14 is provided with air holes 14 a for supplying air (oxygen) to the positive electrode 11. The positive electrode current collector plate 14 is electrically connected to a positive electrode lead wire 15 formed of a conductive material.

  A negative electrode current collector plate 16 made of a conductive material is disposed on the surface of the membrane electrode assembly 10 on the negative electrode electrode diffusion layer 12b side. The negative electrode current collector plate 16 is provided with a hydrogen introduction hole 16 a for supplying fuel (hydrogen) to the negative electrode 12. The negative electrode current collector plate 16 is electrically connected to a negative electrode lead wire 17 formed of a conductive material. Further, a hydrogen supply pipe 24 is disposed on the negative electrode current collector plate 16 so as to communicate with the negative electrode 12 through the hydrogen introduction hole 16a.

  The positive electrode current collector plate 14, the membrane electrode assembly 10 and the negative electrode current collector plate 16 are stacked in a pressurized state via a sealing material 18 formed of an elastic material. Thereby, the inside of the fuel cell 100 is maintained in an airtight state, and hydrogen can be prevented from leaking to the outside.

  The hydrogen generation apparatus 200 includes a hydrogen generation container 21 and a water supply container 22. A hydrogen generating material 23 is accommodated in the hydrogen generating container 21. The hydrogen generation vessel 21 includes a hydrogen outlet 21a and a water inlet 21b. A hydrogen supply pipe 24 is attached to the hydrogen outlet 21a, and the hydrogen supply pipe 24 connects the negative electrode 12 of the fuel cell 100 and the hydrogen generation container 21 of the hydrogen generator 200 in an airtight state as described above. Yes. A water supply pipe 28a is connected to the water introduction port 21b.

  A pressure release valve 25 is installed at an end of the hydrogen supply pipe 24. A cooling unit 26 is provided in the middle of the hydrogen supply pipe 24. Since the reaction between the hydrogen generating material 23 and water in the hydrogen generating container 21 is an exothermic reaction, the temperature in the hydrogen generating container 21 may be close to 100 ° C., and water is discharged into the hydrogen supply pipe 24 together with water. However, by providing the cooling unit 26, the water vapor can be returned to the water, and hydrogen with higher purity can be supplied to the fuel cell 100. As long as the cooling unit 26 has high heat dissipation characteristics, the structure, material, and the like are not particularly limited. In order to reduce the size and weight of the fuel cell power generation system, the cooling unit 26 can be omitted.

  The material, shape, and the like of the hydrogen generation container 21 are not particularly limited, but since the hydrogen generation material 23 is used as a reaction container for reacting water with water, the structure may be such that supplied water and generated hydrogen do not leak to the outside. In addition, when the water inlet 21b is sealed, the internal pressures of the hydrogen generation vessel 21 and the hydrogen supply pipe 24 must be maintained at a pressure lower than atmospheric pressure. For this reason, the material used for the hydrogen generation vessel 21 is preferably a material that hardly leaks water and hydrogen and has heat resistance, that is, a material that does not break even when heated to about 100 ° C. For example, metals such as aluminum, titanium, and nickel, and resins such as polyethylene, polypropylene, and polycarbonate, ceramics such as alumina, silica, and titania, and materials such as heat-resistant glass can be used. The shape used for the hydrogen generation vessel 21 may be a prismatic shape, a cylindrical shape, or the like.

  The material, shape, and the like of the hydrogen supply pipe 24 and the water supply pipe 28a are not particularly limited, and the same material as that of the hydrogen generation vessel 21 can be used as the material. Can be used.

  Further, a filter may be provided at the hydrogen outlet 21 a or the hydrogen supply pipe 24 so that the hydrogen generating material 23 and water in the hydrogen generating container 21 do not flow out to the fuel cell 100 side. The filter is not particularly limited as long as it has a characteristic of allowing gas to pass but not allowing liquid and solid to pass through. For example, a nonwoven fabric made of polypropylene (PP) can be used.

  It is preferable that a heat insulating material is further disposed outside the hydrogen generation container 21. This is because the reaction between water and the hydrogen generating material 23 is an exothermic reaction, and it becomes easy to maintain the temperature within the hydrogen generating container 21 at a temperature at which the exothermic reaction can be maintained by the heat insulating material, and is less susceptible to the influence of the outside air temperature. The material of the heat insulating material is not particularly limited as long as it has a high heat insulating property. For example, a porous heat insulating material such as polystyrene foam or polyurethane foam, a heat insulating material having a vacuum heat insulating structure, or the like can be used.

  The hydrogen generating material 23 is not particularly limited as long as it includes a hydrogen generating material that reacts with water to generate hydrogen. At least one selected from the group can be suitably used. Elements other than the element that is the main component of the alloy are not particularly limited. Here, the main component means that the element is contained in an amount of 80% by weight or more, more preferably 90% by weight or more based on the whole alloy. These hydrogen generating substances are substances that do not easily react with water at room temperature, but are easily exothermic with water when heated. In this specification, normal temperature is a temperature in the range of 20 to 30 ° C.

  For example, the reaction between aluminum and water is considered to proceed according to any of the following formulas (1) to (3). The calorific value according to the following formula (1) is 419 kJ / mol.

(Formula 1)
2Al + 6H ₂ O → Al ₂ O ₃ .3H ₂ O + 3H ₂ (1)
2Al + 4H ₂ O → Al ₂ O ₃ .H ₂ O + 3H ₂ (2)
2Al + 3H ₂ O → Al ₂ O ₃ + 3H ₂ (3)
The hydrogen generating substance is not particularly limited by the average particle diameter, but the average particle diameter is preferably 0.1 μm or more and 100 μm or less, and more preferably 0.1 μm or more and 50 μm or less. In general, a stable oxide film is formed on the surface of a hydrogen generating substance. For this reason, plate-like, block-like, and bulk-like hydrogen generating materials having a particle diameter of 1 mm or more do not proceed with reaction with water even when heated, and may not substantially generate hydrogen. However, when the average particle size of the hydrogen generating material is 100 μm or less, the action of suppressing the reaction with water by the oxide film is reduced, and although it is difficult to react with water at room temperature, the reactivity with water increases when heated, and hydrogen is generated. The reaction will continue. If the average particle size of the hydrogen generating substance is 50 μm or less, it can react with water and generate hydrogen even under mild conditions of about 40 ° C. On the other hand, when the average particle size of the hydrogen generating material is less than 0.1 μm, the ignitability becomes high and handling becomes difficult, or the filling density of the hydrogen generating material decreases and the energy density tends to decrease. For this reason, it is desirable that the average particle size of the hydrogen generating substance be within the above range.

  In addition, the average particle diameter as used in this specification means the value of the particle diameter in the volume-based integrated fraction of 50%. As a method for measuring the average particle diameter, for example, a laser diffraction / scattering method or the like can be used. Specifically, it is a particle diameter distribution measurement method using a scattering intensity distribution detected by irradiating a measurement target substance dispersed in a liquid phase such as water with laser light. As a particle size distribution measuring apparatus using a laser diffraction / scattering method, for example, “Microtrack HRA” manufactured by Nikkiso Co., Ltd. can be used.

  In addition, the shape of the hydrogen generating substance is not particularly limited, but the average particle diameter may be in the form of particles or flakes within the above range.

  In order to easily start the reaction between water and the hydrogen generating material, it is desirable to heat at least one of the hydrogen generating material and water. Even if the water supply and heating to the inside of the hydrogen generating container 21 are performed simultaneously, Good.

  The temperature for heating at least one of the hydrogen generating substance and water is preferably 40 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower. The temperature at which this exothermic reaction can be maintained is usually 40 ° C. or higher as described above. Once the exothermic reaction starts and hydrogen is generated, the internal pressure of the container may increase and the boiling point of water may increase. Although the internal temperature may reach 120 ° C., it is preferably 100 ° C. or less from the viewpoint of controlling the hydrogen generation rate.

  The heating may be performed only at the start of the exothermic reaction. This is because once the exothermic reaction between water and the hydrogen generating substance is started, the subsequent reaction can be continued by the heat of the exothermic reaction.

  Although the heating method is not particularly limited, heating can be performed using heat generated by energizing the resistor. For example, at least one of the hydrogen generating substance and water can be heated by attaching the resistor to the outside of the hydrogen generating container 21 to generate heat and heating the hydrogen generating container 21 from the outside. The type of the resistor is not particularly limited, and for example, a metal heating element such as a nichrome wire or a platinum wire, silicon carbide, a PTC thermistor, or the like can be used.

  The heating can also be performed by heat generation due to a chemical reaction of the exothermic substance. As the exothermic substance, a substance which becomes an hydroxide or a hydrate by exothermic reaction with water, a substance which generates hydrogen by exothermic reaction with water, or the like can be used. Examples of the substance that becomes exothermic reaction with water to form a hydroxide or a hydrate include, for example, an alkali metal oxide (for example, lithium oxide), an alkaline earth metal oxide (for example, calcium oxide, magnesium oxide). Etc.), alkaline earth metal chlorides (eg, calcium chloride, magnesium chloride, etc.), alkaline earth metal sulfate compounds (eg, calcium sulfate, etc.), and the like can be used. Examples of the substance that generates hydrogen by exothermic reaction with water include alkali metals (eg, lithium, sodium, etc.), alkali metal hydrides (eg, sodium borohydride, potassium borohydride, lithium hydride, etc.) Etc.) can be used. These substances can be used alone or in combination.

  The exothermic substance is mixed with the hydrogen generating substance and placed in the hydrogen generating container 21 as the hydrogen generating material 23, and water and the exothermic substance are reacted exothermically by adding water, whereby hydrogen is generated inside the hydrogen generating container 21. The generated material and water can be heated directly. In addition, by disposing this exothermic substance outside the hydrogen generating container 21 to generate heat and heating the hydrogen generating container 21 from the outside, at least one of the hydrogen generating substance and water can be heated.

  Moreover, as the exothermic substance, a substance that exothermicly reacts with a substance other than water, for example, a substance that exothermicly reacts with oxygen such as iron powder is also known. Since this exothermic substance must introduce oxygen for an exothermic reaction, it is used by being placed outside the hydrogen generation vessel 21.

  According to the fuel cell power generation system of the present invention described above, although it varies depending on conditions, for example, the theoretical hydrogen generation amount when it is assumed that all the hydrogen generating substances have reacted (in the case of aluminum, the theoretical hydrogen generation amount per gram is Therefore, the actual amount of hydrogen generated is approximately 50% or more, more preferably 60% or more, and hydrogen can be efficiently generated.

  On the other hand, water 27 is stored inside the water supply container 22. Further, the water supply container 22 includes a water outlet 22a and an air inlet 22b. A water supply pipe 28b is attached to the water outlet 22a. Further, the water supply pipe 28 b is provided with a backflow prevention valve 29 and a flow rate control unit 30. The specific configuration of the flow rate control unit 30 is not particularly limited, and for example, a flow rate adjustment valve, a squeezed pipe with a reduced pipe diameter, or the like can be used. In addition, the backflow prevention valve 29 can also be arrange | positioned at the water inlet 21b of the hydrogen generation container 21. FIG.

  The water supply pipes 28a and 28b connect the water supply container 22 and the hydrogen generation container 21 as described above.

  An air introduction pipe 31 is attached to the air introduction port 22b. In addition, a gas-liquid separation membrane 32 is installed in the air introduction pipe 31. The material of the gas-liquid separation membrane 32 is not particularly limited. For example, a microporous membrane made of polytetrafluoroethylene (PTFE) or the like can be used.

  The material, shape, etc. of the water supply container 22 are not particularly limited. What is necessary is just to use the same material, shape, etc. as the above-mentioned hydrogen generating container 21. FIG. Further, the material, shape, and the like of the water supply pipes 28a, 28b and the air introduction pipe 31 are not particularly limited, and the same material as that of the water supply container 22 can be used as the material, and the cross section is circular in shape. Or the like can be used. However, when the air inlet 22b and the air inlet pipe 31 are not provided in the water supply container 22, the water supply container 22 can be deformed by atmospheric pressure in order to maintain the internal pressure of the water supply container 22 at atmospheric pressure. It is necessary to form a material, for example, a resin such as PP.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to a following example.

<Fabrication of fuel cell>
A fuel cell having a structure substantially similar to the structure shown in FIG. 1 was produced as follows.

For the positive electrode 11 and the negative electrode 12, a fuel cell electrode “LT140E-W” (Pt amount: 0.5 mg / cm ² ) manufactured by E-TEK, in which platinum (Pt) -carrying carbon was coated on a carbon cloth was used. . As the solid electrolyte membrane 13, a solid electrolyte membrane “Nafion 112” (trade name) manufactured by DuPont was used. The positive electrode 11, the negative electrode 12, and the solid electrolyte membrane 13 were laminated and integrated, and used as the membrane electrode assembly 10. The electrode area of the membrane electrode assembly 10 was 10 cm ² .

  The positive electrode current collector plate 14 having air holes 14a, the negative electrode current collector plate 16 having hydrogen introduction holes 16a, the positive electrode lead wire 15 and the negative electrode lead wire 17 were formed of stainless steel (SUS304) plated with gold.

  Silicone rubber was used for the sealing material 18, and a pressure relief valve with an opening pressure of 0.1 MPa was used for the pressure release valve.

<Production of hydrogen generator>
A hydrogen generator having a structure substantially similar to the structure shown in FIG. 1 was produced as follows.

As the hydrogen generation container 21, a prismatic container made of aluminum having an internal volume of 5 cm ³ was used. As the hydrogen supply pipe 24 and the water supply pipe 28a, aluminum pipes having an inner diameter of 2 mm and an outer diameter of 3 mm were used. As the hydrogen generating material 23, 2.2 g of aluminum powder having an average particle diameter of 3 μm was used as a hydrogen generating material, and 0.3 g of calcium oxide was used as a heat generating material. After filling the main body container portion with the hydrogen generating material 23, the hydrogen generating container 21 was produced by sealing with a lid provided with a hydrogen supply pipe 24 and a water supply pipe 28 a.

As the water supply container 22, an aluminum prismatic container having an internal volume of 10 cm ³ was used. As the water supply pipe 28b, an aluminum pipe having an inner diameter of 2 mm and an outer diameter of 3 mm was used. For the air introduction pipe 31, an aluminum pipe having an inner diameter of 4 mm and an outer diameter of 5 mm was used. After pouring 7 g of water from the air introduction pipe 31 into the water supply container 22, a gas-liquid separation membrane 32 made of a PTFE microporous membrane was installed at the outer end of the air introduction pipe 31.

  A flow rate control unit 30 made of a resin tube having an inner diameter of 0.1 mm is provided in the middle portion of the water supply pipe 28b. A backflow prevention valve 29 is disposed at the end of the water supply pipe 28b. A water supply pipe 28 a of the hydrogen generation container 21 is connected to the backflow prevention valve 29. In this embodiment, the cooling unit 26 is not provided.

<Power generation by fuel cell power generation system>
After injecting 1 mL of water into the hydrogen generation vessel 21 from the water supply pipe 28a, the water supply pipe 28a and the backflow prevention valve 29 were immediately connected. The temperature of the hydrogen generation vessel 21 increased due to the water injection, and the generation of hydrogen was started. Along with this, the fuel cell started generating electricity. When the generated hydrogen was consumed by the fuel cell and the amount of hydrogen decreased, the internal pressures of the hydrogen supply pipe 24 and the hydrogen generation container 21 from the vicinity of the negative electrode 12 became smaller than the atmospheric pressure. That is, the internal pressure of the hydrogen generation container 21 became negative with respect to the internal pressure of the water supply container 22 maintained at atmospheric pressure. Due to the negative pressure, the water 27 in the water supply container 22 flows into the hydrogen generation container 21 through the water supply pipes 28a and 28b, and the generation of hydrogen is started again. Thereby, the internal pressure of the hydrogen generation container 21 increased, and the inflow of water from the water supply container 22 was stopped. Since the generated hydrogen is continuously consumed by the fuel cell, the inflow and stop of water from the water supply container 22 to the hydrogen generation container 21 are repeated many times, and without the power of the pump or the like for about 60 minutes, I was able to maintain power generation.

  FIG. 2 is a graph showing the relationship between the output of the fuel cell, the surface temperature of the hydrogen generation container, and the elapsed time in this example. From FIG. 2, in the fuel cell power generation system of this example, the surface temperature of the hydrogen generation vessel was maintained at about 75 ° C. or higher, and the output of the fuel cell was also maintained at about 1.5 W or higher. It can be seen that the generated substance continuously reacted and hydrogen was stably supplied to the fuel cell.

  As described above, the fuel cell power generation system of the present invention can maintain the power generation of the fuel cell continuously and stably without the power to supply water. Can be provided.

It is a conceptual diagram which shows an example of the fuel cell power generation system of this invention. It is the figure which showed the relationship between the output of the fuel cell in the Example of this invention, the surface temperature of a hydrogen generation container, and elapsed time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Fuel cell 10 Membrane electrode assembly 11 Positive electrode 11a Positive electrode catalyst layer 11b Positive electrode diffusion layer 12 Negative electrode 12a Negative electrode catalyst layer 12b Negative electrode diffusion layer 13 Solid electrolyte membrane 14 Positive electrode current collector plate 14a Air hole 15 Positive electrode lead wire 16 Negative electrode current collector plate 16a Hydrogen inlet 17 Negative electrode lead 18 Sealing material 200 Hydrogen generator 21 Hydrogen generator 21a Hydrogen outlet 21b Water inlet 22 Water supply container 22a Water outlet 22b Air inlet 23b Hydrogen generating material 24 Hydrogen supply pipe 25 Pressure release valve 26 Cooling unit 27 Water 28a, 28b Water supply pipe 29 Backflow prevention valve 30 Flow control unit 31 Atmospheric introduction pipe 32 Gas-liquid separation membrane

Claims (8)

A fuel cell comprising a positive electrode for reducing oxygen, a negative electrode for oxidizing hydrogen, and a solid electrolyte disposed between the positive electrode and the negative electrode; and
A fuel cell power generation system including a hydrogen generation container containing a hydrogen generation material and a water supply container containing water, and comprising a hydrogen generation device that generates hydrogen when the hydrogen generation material reacts with the water Because
The negative electrode and the hydrogen generation container are connected by a fuel supply channel,
The water supply container and the hydrogen generation container are connected by a water supply channel,
The internal pressure of the water supply container is maintained at atmospheric pressure;
A fuel cell power generation system, wherein when the internal pressure of the hydrogen generation container becomes negative than atmospheric pressure, the water is supplied from the water supply container to the hydrogen generation container by the negative pressure.   The fuel cell power generation system according to claim 1, wherein the water supply container includes an air inlet.   The fuel cell power generation system according to claim 1, wherein the water supply container is formed of a material that can be deformed by atmospheric pressure.   The fuel cell power generation system according to claim 1, wherein the water supply channel includes a backflow prevention valve.   The fuel cell power generation system according to claim 1, wherein the water supply channel includes a flow rate control unit.   The fuel cell power generation system according to claim 1, wherein the fuel supply channel includes a pressure release valve.   The fuel cell power generation system according to claim 2, wherein the air introduction port includes a gas-liquid separation membrane.   2. The fuel cell power generation system according to claim 1, wherein the hydrogen generating material includes at least one hydrogen generating material selected from the group consisting of aluminum, silicon, zinc, magnesium, and an alloy mainly composed of these elements.

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