JP4982951B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell including a cell module having a hollow electrolyte membrane.

  A fuel cell directly converts chemical energy into electrical energy by supplying fuel and an oxidant to two electrically connected electrodes and causing the fuel to be oxidized electrochemically. Unlike thermal power generation, it is not subject to the Carnot cycle, so it exhibits high energy conversion efficiency. Among them, the solid polymer electrolyte fuel cell is a fuel cell that uses a solid polymer electrolyte membrane as an electrolyte, and has advantages such as easy miniaturization and operation at a low temperature. It is attracting attention as a power source for mobile objects.

In the solid polymer electrolyte fuel cell, when hydrogen is used as the fuel, the reaction of the formula (1) proceeds at the anode.
H ₂ → 2H ⁺ + 2e ⁻ (1)
The electrons generated by the equation (1) reach the cathode after working with an external load via an external circuit. Then, the proton generated in the formula (1) moves by electroosmosis from the anode side to the cathode side in the solid polymer electrolyte membrane in a state of being hydrated with water.

Further, when oxygen is used as the oxidizing agent, the reaction of the formula (2) proceeds at the cathode.
4H ⁺ + O ₂ + 4e ⁻ → 2H ₂ O (2)
The water produced at the cathode mainly passes through the gas diffusion layer and is discharged to the outside.
As described above, the fuel cell is a clean power generation device having no emission other than water.

  Conventionally, as a solid polymer electrolyte fuel cell, a catalyst layer serving as an anode and a cathode is provided on one surface of a planar solid polymer electrolyte membrane, and the resulting planar membrane / electrode assembly is obtained. There has been developed a fuel cell stack obtained by laminating a plurality of flat single cells prepared by further providing gas diffusion layers on both sides and finally sandwiching them with a planar separator.

In order to improve the output density of the solid polymer electrolyte fuel cell, a proton conductive polymer membrane having a very thin film thickness is used as the solid polymer electrolyte membrane. The film thickness of 100 μm or less is the mainstream, and even if a thinner electrolyte membrane is used to further improve the power density, the thickness of the single cell cannot be dramatically reduced from the present one. Similarly, the catalyst layer, the gas diffusion layer, the separator, and the like have been made thinner, but there is a limit to the improvement of the output density per unit volume even by making all these members thinner.
In addition, a sheet-like carbon material having excellent corrosivity is usually used for the separator. This carbon material itself is also expensive. However, in order to distribute the fuel gas and the oxidant gas almost uniformly over the entire surface of the planar membrane / electrode assembly, a gas is usually provided on the surface of the separator. Since the groove to be the flow path is finely processed, the processing makes the separator very expensive, which increases the manufacturing cost of the fuel cell.

  In addition to the above problems, it is a technology to reliably seal the periphery of a plurality of unit cells stacked so that fuel gas and oxidant gas do not leak from the gas flow path in the flat unit cell. There are many problems such as difficulty in power generation and reduction in power generation efficiency due to deflection or deformation of the planar membrane / electrode assembly.

In recent years, a solid polymer electrolyte fuel cell has been developed in which a cell module having electrodes on the inner surface side and outer surface side of a hollow electrolyte membrane is used as a basic power generation unit. (For example, see Patent Documents 1 to 4).
Usually, in a fuel cell having such a hollow cell module, it is not necessary to use a member corresponding to a separator used in a flat type. Since different types of gas are supplied to the inner surface and the outer surface for power generation, it is not necessary to form a gas flow path. Therefore, the manufacturing cost is expected to be reduced. Further, since the cell module has a three-dimensional shape, the specific surface area with respect to the volume can be increased as compared with the flat single cell, and the power generation output density per volume can be expected to be improved.

By the way, in a polymer electrolyte fuel cell using a solid polymer electrolyte membrane that is one of proton conducting membranes as an electrolyte membrane, protons generated at the anode are hydrated with water in the polymer electrolyte membrane. Since the polymer electrolyte membrane moves from the cathode side to the cathode side, proton conductivity decreases when the water content of the polymer electrolyte membrane is low. Therefore, it is important to keep the moisture content of the polymer electrolyte membrane high and prevent drying. In addition, if the electrodes formed on both sides of the polymer electrolyte membrane are dry, the electrolyte membrane cannot be kept in a high wet state, so that the electrode also needs to be in a high wet state.
On the other hand, if excessive moisture is present in the electrode and the electrode is in a water-immersed state, the diffusibility of the reaction gas in the electrode is reduced, and a sufficient amount of the reaction gas necessary for power generation is not supplied to the electrode. The power generation performance of the battery is reduced.
Therefore, in the polymer electrolyte fuel cell, it is necessary to keep the electrolyte membrane and the electrode in a proper wet state.

JP-A-9-223507 JP 2002-124273 A JP 2002-158015 A Japanese Patent Laid-Open No. 2002-260685

Since the hollow cell module has a large specific surface area as described above, the amount of water released from the electrode provided on the outer surface of the cell module is particularly large. Therefore, the electrode and the electrolyte membrane are easily dried, and the power generation performance of the fuel cell is lowered.
An object of the present invention is to provide a fuel cell having a hollow cell module, in which the humidity of the environment surrounding the cell module can be adjusted to a state suitable for power generation of the fuel cell.

  The fuel cell of the present invention is a fuel cell comprising a cell module having a hollow electrolyte membrane and a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, the cell module comprising the pair of electrodes. Among them, an electrode for generating generated water is provided on the outer surface side of the hollow electrolyte membrane, and is housed in a moisture-impermeable container, and the container has humidity adjusting means for adjusting the humidity of the internal space of the container. It is provided.

In the fuel cell of the present invention, an electrode for generating generated water is provided on the outer surface side of the hollow cell module. However, since the cell module is housed in a container having moisture impermeability, The inside of the container can be kept in a high humidity state by moisture such as water vapor or water droplets discharged from an electrode for generating generated water provided on the outer surface side. As a result, the electrolyte membrane and the electrode of the cell module are maintained in a moderately wet state, so that it is possible to prevent a decrease in power generation performance of the fuel cell due to drying of the electrolyte membrane.
Moreover, since the container in which the cell module is accommodated is provided with a humidity adjusting means capable of adjusting the humidity of the internal space of the container, it is possible to prevent the humidity in the container from becoming excessively high. It is possible to prevent a decrease in power generation performance due to excess water remaining in the electrode.

  As an example of the humidity adjusting means, there is an opening / closing window capable of communicating and blocking the internal space of the container with the external space. In addition, as a specific configuration example of the opening / closing window, one that can be opened / closed by a shutter portion that slides along the outer wall of the container and that can adjust the area of the opening portion of the opening / closing window can be mentioned.

  The humidity of the internal space of the container can be adjusted according to the humidity detected by the humidity detection means by providing humidity detection means for detecting the humidity of the internal space of the container. Examples of the humidity detecting means include means for detecting the output of the fuel cell, and the humidity of the internal space of the container can be adjusted according to the output detected by the output detecting means.

  According to the present invention, since the wet state of the cell module can be appropriately adjusted to a state suitable for the operation of the fuel cell, the influence of the inappropriate wet state of the cell module on the power generation performance of the fuel cell is small. It shows excellent power generation performance and can supply stable power.

  The fuel cell of the present invention is a fuel cell comprising a cell module having a hollow electrolyte membrane and a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, the cell module comprising the pair of electrodes. Among them, an electrode for generating generated water is provided on the outer surface side of the hollow electrolyte membrane, and is housed in a moisture-impermeable container, and the container has humidity adjusting means for adjusting the humidity of the internal space of the container. It is characterized by being provided.

  Hereinafter, the fuel cell of the present invention will be described by taking as an example a case where a solid polymer electrolyte membrane which is a kind of proton conducting membrane is used as an electrolyte membrane. Here, a perfluorocarbon sulfonic acid resin membrane is used as the solid polymer electrolyte membrane.

  First, an embodiment of the fuel cell of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an example of a cell module used in the present invention.

  1, the cell module 101 includes a tube-shaped electrolyte membrane (perfluorocarbon sulfonic acid resin membrane) 1 and may be referred to as an electrode (hereinafter referred to as a first electrode) that generates generated water. The other electrode (hereinafter, referred to as a second electrode, which is referred to as a second electrode in the present embodiment) 3 is formed on the hollow outer surface side of the electrolyte membrane 1. Is formed on the hollow inner surface side. Inside the second electrode (anode) 3, a hollow portion (usually a flow path for a fuel gas such as hydrogen gas) 4 into which a reaction gas supplied to the second electrode flows is formed. Current collectors 5 and 6 are connected to the first electrode 2 and the second electrode 3, respectively, and one end of the current collectors 5 and 6 functions as an output terminal.

  FIG. 2 is a cross-sectional perspective view showing an embodiment of a container in which a plurality of cell modules are arranged and accommodated. In FIG. 2, the plurality of cell modules 101 are accommodated in the container 7 in a state of being supported and arranged by a support plate (not shown). The plurality of cell modules accommodated in the container 7 constitutes a cell group in which the cathode terminal 5 (not shown) and the anode terminal 6 (not shown) are bundled and connected in parallel or in series. The internal space of the container 7 is an oxidant gas (generally air) supply source (not shown), and the hollow portion 4 of the cell module 101 is a fuel gas (generally hydrogen gas) supply source (not shown). The reaction gas is supplied to each of the electrodes 2 and 3, respectively.

  The container 7 is impermeable to moisture such as water vapor and water droplets. However, it does not have to be completely impermeable to water, and it is sufficient that the humidity of the internal space and the external space of the container 7 can be made different. In the present embodiment, the container 7 passes the fuel gas through the oxidant gas inlet and the oxidant gas outlet through which the oxidant gas flows into the internal space of the container 7 and the hollow portion 4 of the cell module 101. The parts other than the fuel gas inlet and the fuel gas outlet and the open / close window 8 (when opened) are made of a material that is blocked from the external space and does not substantially transmit moisture.

Since the cell module of the fuel cell of the present invention is provided with the first electrode (cathode) 2 for generating generated water on the outer surface side of the hollow electrolyte membrane 1, the moisture impermeable container as described above is provided. 7, moisture discharged from the first electrode (water generated by the first electrode, water supplied to the electrode together with the reaction gas, and moved from the second electrode accompanying protons) The humidity of the internal space of the container 7 is kept high by moisture and the like. Accordingly, the wet state of the electrode and electrolyte membrane of the cell module is kept high, so that it is possible to prevent the power generation performance of the fuel cell from being lowered due to the drying of the electrode and electrolyte membrane. As described above, in the present invention, the wet state in the cell module is kept high by utilizing moisture discharged from the electrode provided on the hollow outer surface side of the cell module, and the wet state of the cell module is made suitable for power generation. can do.
The fuel cell of the present invention also has the advantage that the temperature of the cell module can be maintained and the electrode reaction can be stabilized by accommodating the cell module in a container that is somewhat blocked from the external space. Have.

In the present embodiment, the container 7 has a cylindrical shape, but the shape of the container 7 is not particularly limited, and may be appropriately designed. The material for forming the container 7 is not particularly limited as long as it has moisture impermeability, but the arrangement of the cell modules to be accommodated is maintained, and the cell modules are mechanically operated as necessary. It is preferable that it has the intensity | strength which can protect from an impact. Also, in the polymer electrolyte fuel cell, the water produced at the cathode itself is pure water, but the water discharged from the cathode as a result of mixing with water molecules etc. that have moved along with protons from the anode side. Since it usually shows acidity, it is preferably a material having excellent corrosion resistance. Specific examples include plastic, stainless steel, gold, Ti alloy, and stainless steel, gold, and Ti alloy are particularly preferable. The stainless steel SUS316 or the like, as the Ti alloy Tiva, TiSi _2, and the like. The container may be formed of a single material or a combination of a plurality of materials.

The container 7 is provided with an opening / closing window 8 capable of communicating and blocking the internal space of the container 7 with the external space as humidity adjusting means for adjusting the humidity of the internal space of the container 7. When the open / close window 8 is closed, the internal space of the container 7 can maintain high humidity. On the other hand, when the open / close window 8 is opened, the internal space of the container 7 communicates with the external space, and moisture can be lowered by releasing moisture into the external space.
That is, when the humidity of the internal space of the container 7 is low and the electrolyte membrane or electrode constituting the cell module is dry, the humidity in the container is increased by closing the open / close window 8 to wet the electrolyte membrane or electrode. A state can be made high. On the other hand, when the humidity in the container 7 rises excessively and excessive moisture stays in the electrode, which prevents the reaction gas from diffusing in the electrode, the humidity in the container is lowered by opening the opening / closing window 8. The electrode can be in a moderately wet state.

  As described above, according to the fuel cell of the present invention, it is possible to adjust the humidity in the container housing the cell module by the humidity adjusting means such as the open / close window 8, and as a result, the electrolyte membrane and the electrode Can be maintained at a humidity suitable for power generation of the fuel cell. Therefore, the fuel cell of the present invention exhibits high power generation performance without being greatly affected by the operating state of the fuel cell, the temperature and humidity of the external space, and the like.

The open / close window 8 is opened and closed with the dew point of the internal space in the container 7 as a guide so that the humidity (relative humidity) of the internal space of the container 7 is suitable for the operation of the fuel cell. The opening and closing time, the degree of opening and closing, and the like may be adjusted according to the humidity and temperature of the external space along with the humidity. At this time, it is preferable to open and close the window so as not to inhibit the diffusion of the reaction gas flowing through the internal space of the container 7.
In this embodiment, since the reaction gas (oxidant gas) supplied to the electrode (cathode 2) provided on the outer surface side of the cell module is air, the external space of the container internal space by the opening / closing window 8 is used. Due to the opening, the problem caused by mixing of the reaction gas flowing through the internal space and the air in the external space does not occur. In the present embodiment, air is freely supplied to the cathode provided on the outer surface side as necessary, so that the partial pressure of oxygen as an electrode reaction component does not change.

  In the fuel cell of the present invention, the configuration of the window provided in the container as the humidification adjusting means may be any as long as the humidity in the container can be adjusted by opening and closing the window. It is not limited. The opening / closing window 8 in the present embodiment shown in FIG. 2 has a structure that can be opened and closed by a shutter portion 9 that slides along the outer wall of the container 7, and the area of the opening portion 10 is determined by the sliding distance of the shutter portion 9. It can be adjusted (FIGS. 2-A to 2-C). The open / close window 8 having such a structure is preferable in that it does not hinder downsizing of the fuel cell because there is almost no exclusive space necessary for opening and closing the window.

As another configuration of the opening / closing window, for example, a configuration including a shutter unit such as a hinged door or a folding door may be used, or a configuration including a shutter unit that can be folded in an accordion manner. Further, in the configuration including the sliding shutter unit as shown in FIG. 2, the shutter unit may be composed of a plurality, and the sliding direction of the shutter unit is not particularly limited. Further, the size of the window is not particularly limited, and may be appropriately determined according to the size of the container, the environment in which the fuel cell is used, and the like.
Further, since the opening / closing window 8 is a means for adjusting the humidity in the container 7, it is sufficient that the opening 9 of the opening / closing window 8 can pass moisture (water droplets or water vapor), and it can be completely applied to the external space. It does not have to be open. For example, the opening may be covered with a moisture-permeable material such as a perfluorocarbon sulfonic acid resin film, a nylon cloth, or gauze.

  In the present invention, the humidity adjusting means for adjusting the humidity in the container in which the cell module is accommodated is not limited to the open / close window as described above, and the humidity in the container is adjusted to a state suitable for the operation of the fuel cell. Anything can be used.

The humidity of the internal space of the container 7 can be detected by the humidity detecting means and adjusted accordingly by the humidity adjusting means. Examples of the humidity detecting means for detecting the humidity of the internal space include means for detecting the output of the fuel cell. The output of a fuel cell using a solid polymer electrolyte membrane that requires water for ion exchange represented by Nafion (trade name, manufactured by DuPont) changes according to the wet state in the cell module. Since the relationship between the wet state and the output of the fuel cell is unambiguous, the humidity in the container in which the cell module is accommodated can be made suitable for the operation of the fuel cell according to the output of the fuel cell. . Specific examples of a method for adjusting the humidity in the container in accordance with the output of the fuel cell include the following methods. First, the relationship between the humidity around the cell module of the fuel cell to be used and the output is obtained in advance, and a map is created. During operation of the fuel cell, the output is monitored, and the humidity adjusting means is operated according to the monitored output using the map.
As described above, adjusting the humidity according to the output of the fuel cell can ensure that the inside of the container in which the cell module is accommodated is in a humidity state suitable for the operation of the fuel cell. Highly effective in improving performance.

  As other humidity detection means, for example, means for directly detecting the humidity of the internal space of the container, or the humidity at the outlet of the reaction gas (oxidant gas in this embodiment) flowing through the internal space of the container is detected. Means etc. are mentioned. Since the humidity is closer to the humidity in the cell module, it is preferable to directly detect the humidity in the internal space of the container. As a method of measuring the humidity, an electrical resistance hygrometer or a telescopic hygrometer using a polymer moisture sensitive material such as perfluorocarbon sulfonic acid resin (trade name Nafion, manufactured by DuPont, etc.) or bimetal is used. be able to.

Hereinafter, the cell module accommodated in the container will be described in detail.
In FIG. 1, an electrolyte membrane having a tubular hollow shape is used as the hollow electrolyte membrane. However, the hollow electrolyte membrane in the present invention is not limited to a tubular shape, and has a hollow portion, and a reaction occurs in the hollow portion. What is necessary is just to be able to supply a reaction component required for an electrochemical reaction to the inner surface side electrode by flowing gas.

  In the present embodiment, a perfluorocarbon sulfonic acid resin membrane, which is one of solid polymer electrolyte membranes, which is a kind of proton conducting membrane, is described as an electrolyte membrane. However, the fuel cell of the present invention is hollow. Since it has a cell module having a shape, it can take a larger electrode area per unit volume than a fuel cell having a flat cell, so it does not have a higher proton conductivity than a perfluorocarbon sulfonic acid resin membrane. Even when an electrolyte membrane is used, a fuel cell having a high output density per unit volume can be obtained. As the solid polymer electrolyte membrane, perfluorocarbon sulfonic acid resin and materials used for the electrolyte membrane of solid polymer fuel cells can be used. For example, fluorine other than perfluorocarbon sulfonic acid resin can be used. One kind of proton exchange groups such as at least sulfonic acid groups, phosphonic acid groups, and phosphoric acid groups, based on hydrocarbons such as polyolefins such as polystyrene ion exchange resins and polystyrene cation exchange membranes having sulfonic acid groups A complex of a basic polymer and a strong acid, which is disclosed in Japanese Patent Application Laid-Open No. 11-503262, etc., in which a basic polymer such as polybenzimidazole, polypyrimidine, and polybenzoxazole is doped with a strong acid And polymer electrolytes such as solid polymer electrolytes.

A solid polymer electrolyte membrane using such an electrolyte should be reinforced with a perfluorocarbon polymer in the form of a fibril, a fabric, a non-fabric, or a porous sheet, or the membrane surface can be coated with an inorganic oxide or metal. It can also be reinforced. In addition, examples of the perfluorocarbon sulfonic acid resin membrane include commercially available products such as Nafion manufactured by DuPont of the United States and Flemion manufactured by Asahi Glass.
In addition, the proton conductive electrolyte membrane is not limited to the solid polymer electrolyte membrane as described above, a porous electrolyte plate impregnated with a phosphoric acid aqueous solution, a proton conductor made of porous glass, Use hydrogelated phosphate glass, organic-inorganic hybrid proton conductive membrane with proton conductive functional groups introduced into the surface and pores of nanoporous glass, inorganic metal fiber reinforced electrolyte polymer, etc. Can do.

  Each electrode provided on the inner surface and the outer surface of the perfluorocarbon sulfonic acid resin film can be formed using an electrode material used in a polymer electrolyte fuel cell. Usually, an electrode configured by laminating a catalyst layer and a gas diffusion layer in order from the electrolyte membrane side is used.

  The catalyst layer contains catalyst particles and may contain a proton conductive material for increasing the utilization efficiency of the catalyst particles. As the proton conductive material, those used as the material of the electrolyte membrane can be used. As the catalyst particles, catalyst particles in which a catalyst component is supported on a conductive material such as a carbon material such as carbonaceous particles or carbonaceous fibers are preferably used. Since the fuel cell of the present invention has a cell module having a hollow shape, the electrode area per unit volume can be made larger than that of a fuel cell having a flat cell. Even when components are used, a fuel cell having a high output density per unit volume can be obtained. The catalyst component is not particularly limited as long as it has a catalytic action for hydrogen oxidation reaction at the anode and oxygen reduction reaction at the cathode. For example, platinum (Pt), ruthenium (Ru), iridium (Ir) , Rhodium (Rh), palladium (Pd), osmium (Os), tungsten (W), lead (Pb), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn) , Vanadium (V), molybdenum (Mo), gallium (Ga), aluminum (Al) and other metals, or alloys thereof. Preferable are platinum and an alloy made of platinum and another metal such as ruthenium.

  As the gas diffusion layer, a conductive material mainly composed of a carbon material such as carbonaceous particles and / or carbonaceous fibers can be used. The sizes of the carbonaceous particles and the carbonaceous fibers may be appropriately selected in consideration of the dispersibility in the solution when the gas diffusion layer is produced, the drainage property of the obtained gas diffusion layer, and the like. The configuration of each electrode provided on the inner and outer surfaces of the electrolyte membrane, the material used for the electrode, and the like may be the same or different. The gas diffusion layer is impregnated with, for example, polytetrafluoroethylene, polyvinylidene fluoride (PVDF), perfluorocarbon alkoxyalkane, ethylene-tetrafluoroethylene polymer, or a mixture thereof from the viewpoint of enhancing the drainage of moisture such as generated water. It is preferable to carry out water repellent treatment by forming a water repellent layer using these substances.

The method of providing a pair of electrodes on the inner and outer surfaces of the tubular electrolyte membrane is not particularly limited. For example, first, a tubular electrolyte membrane is prepared. It does not specifically limit as a method of forming a tubular electrolyte membrane, You may use the electrolyte membrane formed in the tube shape of a commercial item. Then, a solution containing electrolyte and catalyst particles is applied and dried on the inner and outer surfaces of the tubular electrolyte membrane to form a catalyst layer, and carbonaceous particles and / or carbonaceous fibers are contained on the two catalyst layers. The method of apply | coating and drying a solution and forming a gas diffusion layer is mentioned. At this time, the catalyst layer and the gas diffusion layer are formed so that a hollow portion exists on the inner surface of the gas diffusion layer formed on the inner surface side of the electrolyte membrane.
Alternatively, first, a carbon material such as carbonaceous particles and / or carbonaceous fibers and formed into a tube shape (tubular carbonaceous material) is used as a gas diffusion layer of the second electrode (anode), and the gas A solution containing an electrolyte and catalyst particles is applied to the outer surface of the diffusion layer and dried to form a catalyst layer to produce a second electrode, and then a solution containing the electrolyte is applied to the outer surface of the catalyst layer and dried. The first catalyst layer is formed on the outer surface of the electrolyte membrane layer and the electrolyte membrane layer, and the first gas diffusion layer is formed by applying and drying a solution containing a carbon material on the outer surface of the first catalyst layer. The method of doing is also mentioned. The tubular carbonaceous material can be obtained, for example, by dispersing a carbon material such as carbonaceous particles and an epoxy and / or phenolic resin in a solvent to form a tubular shape, thermosetting, and firing.

  In addition, the solvent used when forming the electrolyte membrane, the catalyst layer, and the gas diffusion layer may be appropriately selected according to the material to be dispersed and / or dissolved, and the coating method when forming each layer is also as follows. It can be appropriately selected from various methods such as spraying and screeching printing.

  The inner diameter, outer diameter, length, etc. of the tubular cell module can be appropriately designed according to the output required for the fuel cell, the design of the fuel cell such as the equipment to which the fuel cell is applied, and the operating conditions, and are particularly limited. Although not intended, the outer diameter of the tubular electrolyte membrane is preferably 0.01 to 10 mm, more preferably 0.1 to 1 mm, and particularly preferably 0.1 to 0.5 mm. . At present, it is difficult to manufacture a tubular electrolyte membrane having an outer diameter of less than 0.01 mm due to technical problems. On the other hand, when the outer diameter exceeds 10 mm, the surface area with respect to the occupied volume becomes small. This is not preferable because the power generation output per unit volume of the obtained cell module becomes small.

  The perfluorocarbon sulfonic acid resin membrane is preferably thin from the viewpoint of improving proton conductivity, but if it is too thin, the function of isolating gas is lowered and the permeation amount of aprotic hydrogen is increased. However, in comparison with a conventional fuel cell in which flat cells for fuel cells are stacked, a fuel cell manufactured by collecting a large number of hollow cell modules can take a large electrode area. Even when is used, sufficient output is shown. From this viewpoint, the thickness of the perfluorocarbon sulfonic acid resin film is 10 to 100 μm, more preferably 50 to 60 μm, and still more preferably 50 to 55 μm.

Moreover, from the preferable range of the outer diameter and film thickness of the above-mentioned perfluorocarbon sulfonic acid resin film, the preferable range of the inner diameter is 0.01 to 10 mm, more preferably 0.1 to 1 mm, and still more preferably 0. .1 to 0.5 mm.
The thickness of the catalyst layer provided on the inner and outer surfaces of the electrolyte membrane is preferably about 1 to 100 μm, and the thickness of the gas diffusion layer is preferably about 3 to 10 μm.

The cell module having a hollow shape used in the fuel cell of the present invention is not limited to the configuration exemplified above, and a layer other than the catalyst layer and the gas diffusion layer may be provided for the purpose of enhancing the function of the cell module. .
Moreover, the form and material of a collector (5, 6) are not specifically limited. Examples of the current collector material include a metal wire such as stainless steel or a foil. For example, the current collector may be fixed on the electrode with a conductive adhesive such as a carbon-based adhesive or an Ag paste.

  The arrangement state of the cell modules in the usage state of the fuel cell is not particularly limited, and the longitudinal direction may be parallel to, inclined, or perpendicular to the direction of gravity. Moreover, the number of cell modules accommodated in one container, the connection method (parallel connection, series connection) between cell modules, etc. are not specifically limited. For example, a plurality of cell modules are arranged and a group of cells connected in series and / or in parallel is accommodated in a container, and a plurality of cell groups accommodated in the container in this way are connected (series connection and / or parallel connection). A cell assembly may be used, or a cell assembly in which a plurality of cell groups are connected in series and / or in parallel may be accommodated in one container.

In the embodiment shown in FIG. 1, a perfluorocarbon sulfonic acid resin film, which is a proton conducting film, is used as the electrolyte film, but the electrolyte film used in the fuel cell of the present invention is particularly limited. Instead, it may be proton-conductive or other ion-conductive such as hydroxide ions or oxide ions (O ²⁻ ). Examples of other ion-conducting electrolytes such as hydroxide ions and oxide ions (O ²⁻ ) include those containing ceramics. In the case of using an oxide ion conductive electrolyte membrane, oxide ions generated on the cathode side pass through the electrolyte membrane and reach the anode side, react with hydrogen to generate water and simultaneously release electrons. Therefore, in this case, since generated water is generated on the anode side, an anode is provided on the outer surface side of the tubular electrolyte membrane, and an oxidizing gas is circulated in the hollow.

It is the schematic which shows one example of the cell module with which the fuel cell of this invention is equipped. It is the schematic which shows the example of 1 which accommodated the cell module of FIG. 1 in the container.

Explanation of symbols

101 ... Cell module 1 ... Hollow electrolyte membrane (perfluorocarbon sulfonic acid resin membrane)
2 ... 1st electrode (cathode)
3. Second electrode (anode)
DESCRIPTION OF SYMBOLS 4 ... Hollow part 5,6 ... Current collector 7 ... Container 8 ... Opening / closing window 9 ... Shutter part 10 ... Opening part

Claims (5)

  A fuel cell comprising a cell module having a hollow electrolyte membrane and a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, wherein the cell module is an electrode that generates generated water of the pair of electrodes. On the outer surface side of the hollow electrolyte membrane and housed in a moisture-impermeable container, the container being provided with humidity adjusting means for adjusting the humidity of the internal space of the container. A fuel cell.   2. The fuel cell according to claim 1, wherein the humidity adjusting means is an opening / closing window capable of communicating and blocking an internal space of the container with an external space.   The fuel cell according to claim 2, wherein the opening / closing window is opened and closed by a shutter portion that slides along the outer wall of the container, and the area of the opening of the opening / closing window can be adjusted.   The humidity detection means which detects the humidity of the internal space of the said container, The humidity of the internal space of the said container is adjusted according to the humidity detected by the said humidity detection means. Fuel cell. 5. The fuel cell according to claim 4, wherein the humidity detecting means is means for detecting the output of the fuel cell, and the humidity of the internal space of the container is adjusted according to the output detected by the output detecting means.

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