JP2005216820A - Direct methanol fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small direct methanol fuel cell suitable as a power source of portable electronic equipment, capable of stably, continuously supplying direct liquid fuel from a fuel storage tank to each unit cell. <P>SOLUTION: A fuel cell A is formed in such a way that an electrolyte layer is installed on the outer surface part of a fuel electrode body and an air electrode layer is installed on the outer surface part of the electrolyte layer to form a unit cell, a plurality of unit cells are connected, a fuel supply body 30 having penetration structure to be connected to the fuel storage tank 10 storing liquid fuel or a fuel electrode body is connected to each unit cell 20 to supply liquid fuel, and the end of the fuel supply body is connected to a spent fuel storage tank 40. A porous body having capillary action and/or a relay core 40a comprising fiber bundles are/is arranged in the spent fuel storage tank 40, spent fuel is exhausted to the spent fuel storage tank 40 through the relay core 40a, and the spent fuel storage tank is released. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a direct methanol fuel cell, and more particularly to a small direct methanol fuel cell suitable for use as a power source for portable electronic devices such as mobile phones, notebook computers, and PDAs.

  In general, a fuel cell includes a fuel cell in which an air electrode layer, an electrolyte layer, and a fuel electrode layer are stacked, a fuel supply unit for supplying fuel as a reducing agent to the fuel electrode layer, and an oxidant for the air electrode layer. As a battery, various types of batteries are used to generate an electrochemical reaction in the fuel cell by the fuel and oxygen in the air to obtain electric power outside. Things are being developed.

In recent years, due to increasing awareness of environmental issues and energy conservation, the use of fuel cells as clean energy sources for various applications has been studied. In particular, power can be generated simply by supplying liquid fuel containing methanol and water directly. Direct methanol fuel cells have attracted attention (see, for example, Patent Documents 1 and 2).
Among these, each liquid fuel cell etc. which utilized capillary force for supply of liquid fuel are known (for example, refer to patent documents 3-7).
Since the liquid fuel cell described in each of these patent documents supplies liquid fuel from a fuel tank to the fuel electrode by capillary force, there is an advantage in downsizing such as not requiring a pump for pumping liquid fuel.

  However, although the liquid fuel cell using only the capillary force of the porous body and / or fiber bundle provided in the fuel storage tank is suitable for downsizing in terms of configuration, the fuel is directly liquid at the fuel electrode. Because it is supplied in a state, it is mounted on a small portable device, and in a usage environment where the front, back, left, right, top and bottom of the battery part constantly changes, fuel tracking becomes incomplete during a long period of use, causing problems such as shutting off the fuel supply This is a cause of hindering the constant supply of fuel to the electrolyte layer.

  Further, as one of solutions to these drawbacks, for example, after introducing liquid fuel into a cell by capillary force, the liquid fuel is vaporized in a fuel vaporization layer and used (for example, Patent Document 8). However, there is a problem that the lack of follow-up of fuel, which is a basic problem, has not been improved, and the fuel cell of this structure is used as a fuel after vaporizing a liquid For this reason, there are problems such as difficulty in miniaturization.

As described above, in the conventional direct methanol fuel cell, when supplying the liquid fuel directly to the fuel electrode, the fuel supply is unstable and the output value during operation is fluctuated. At present, it is difficult to reduce the size to such an extent that it can be mounted on equipment.
In addition, these Patent Documents 1 to 8 disclose the storage of spent fuel, but do not clearly disclose the processing of spent fuel thereafter.
JP-A-5-258760 (Claims, Examples, etc.) JP-A-5-307970 (Claims, Examples, etc.) JP 59-66066 A (Claims, Examples, etc.) JP-A-6-188008 (Claims, Examples, etc.) JP 2003-229158 A (Claims, Examples, etc.) JP 2003-299946 A (Claims, Examples, etc.) JP-A-2003-340273 (Claims, Examples, etc.) JP 2001-102069 A (Claims, Examples, etc.)

  The present invention has been made in view of the problems and current situation of the conventional direct methanol fuel cell described above, and has been made to solve this problem. The liquid fuel can be stably supplied directly to the fuel electrode, so that the spent fuel can be easily used. It is an object of the present invention to provide a direct methanol fuel cell that can be processed and can be miniaturized.

  As a result of intensive studies on the above-described conventional problems, the present inventors constructed an electrolyte layer on the outer surface of a fuel electrode body made of a microporous carbon body, and constructed an air electrode layer on the outer surface of the electrolyte layer. In a fuel cell in which a plurality of unit cells are connected to each other, a fuel supply body connected directly from the fuel storage tank to the fuel supply to each unit cell is connected, and a spent fuel storage tank of a specific structure supplies the fuel By connecting to the end of the body, etc., the direct methanol fuel cell of the above purpose was successfully obtained, and the present invention was completed.

That is, the present invention resides in the following (1) to (10).
(1) A plurality of unit cells formed by constructing an electrolyte layer on the outer surface of the fuel electrode body and constructing an air electrode layer on the outer surface of the electrolyte layer are connected to each unit cell. A fuel supply body having an osmotic structure connected to a fuel storage tank for storing fuel is connected to supply liquid fuel, and the end of the fuel supply body is a fuel cell connected to a spent fuel storage tank, A relay core composed of a porous body and / or a fiber bundle having a capillary force is arranged, and spent fuel is discharged to the spent fuel storage tank through the relay core, and the spent fuel storage tank is opened. A direct methanol fuel cell characterized by being made.
(2) The direct methanol fuel cell as described in (1) above, wherein the spent fuel storage tank is provided with a spent fuel storage body comprising a porous body and / or a fiber bundle having a capillary force. .
(3) The direct methanol fuel cell according to (1) or (2), wherein the capillary force of the relay core of the used fuel storage body is equal to or greater than the capillary force of the fuel supply body.
(4) The direct methanol fuel cell according to any one of the above (1) to (3), wherein a capillary force of the used fuel storage body is greater than or equal to a capillary force of the relay core.
(5) Any one of the above (1) to (4), wherein the discharge mechanism for discharging the used liquid fuel to the used fuel storage body has a collector body. The direct methanol fuel cell described in 1.
(6) The direct methanol fuel according to any one of (1) to (5), wherein the collector body is manufactured by injection molding or an optical modeling technique, or the collector body is configured by a single-wafer body. battery.
(7) The direct methanol fuel cell according to any one of (1) to (6), wherein the collector body surface is adjusted to have a surface free energy higher than that of the used liquid fuel. .
(8) The direct methanol fuel cell as described in any one of (1) to (7) above, wherein the spent fuel storage tank is removable.
(9) The direct methanol fuel cell according to any one of (1) to (8) above, wherein the spent fuel storage tank is provided with a lid that can be opened and closed.
(10) The used fuel storage tank is provided with a minute opening, and the surface free energy around the inner surface of the used storage tank and the minute opening is adjusted to be lower than that of the used liquid fuel. The direct methanol fuel cell according to any one of (1) to (9) above.

According to the present invention, liquid fuel can be stably supplied directly from a fuel storage tank to each unit cell, and spent fuel processing can be easily and stably discharged, and the fuel cell can be downsized. A direct methanol fuel cell is provided that can be achieved.
According to invention of Claims 2-7, the process of the spent fuel to a liquid fuel storage tank can be discharged | emitted stably further.
According to the eighth to tenth aspects, the spent fuel can be more easily processed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1A to 1E are schematic views showing a basic embodiment (first embodiment) of a direct methanol fuel cell (hereinafter simply referred to as “fuel cell”) A of the present invention.
In this fuel cell A, as shown in FIGS. 1A to 1E, a fuel storage tank 10 containing liquid fuel and an electrolyte layer 23 are formed on the outer surface of a fuel electrode body 21 made of a microcarbon porous body. The fuel supply body 30 having a permeation structure connected to the unit cells (fuel cell) 20, 20 and the fuel storage tank 10 formed by constructing the air electrode layer 24 on the outer surface of the electrolyte layer 23. And a spent fuel storage tank 40 provided at the end of the fuel supply body 30, and the unit cells 20 and 20 are connected in series so that fuel is sequentially supplied by the fuel supply body 30. Also, the spent fuel storage tank 40 is provided with a relay core 40a made of a porous body and / or a fiber bundle having a capillary force, and the spent fuel is stored in the spent fuel storage via the relay core 40a. In the configuration to discharge to the tank 40, It has a structure in which the spent fuel pool 40 is open.

Examples of the liquid fuel stored in the fuel storage tank 10 include a methanol liquid composed of methanol and water, but hydrogen ions (H ⁺ ) and electrons are efficiently obtained from a compound supplied as fuel in a fuel electrode body described later. As long as (e ⁻ ) can be obtained, the liquid fuel is not particularly limited and depends on the structure of the fuel electrode body. For example, liquid such as dimethyl ether (DME), ethanol solution, formic acid, hydrazine, ammonia solution, etc. Fuel can also be used.
In the present embodiment, the liquid fuel is occluded in an occlusion body 10 a such as a batting, a porous body, or a fiber bundle housed in the fuel storage tank 10. The occlusion body 10a is not particularly limited as long as it can occlude liquid fuel, and an occlusion body having the same configuration as the fuel supply body 30 described later can be used.

  The material of the fuel storage tank 10 is not particularly limited as long as it has storage stability and durability with respect to the liquid fuel to be stored. Metal such as aluminum and stainless steel, polypropylene, polyethylene, polyethylene Examples thereof include synthetic resins such as terephthalate and glass.

  Each fuel cell 20 as a unit cell has a fuel electrode body 21 made of a micro-columnar carbon porous body, and has a through portion 22 that penetrates the fuel supply body 30 at the center thereof, and the fuel electrode body 21. An electrolyte layer 23 is constructed on the outer surface of the electrode layer, and an air electrode layer 24 is constructed on the outer surface of the electrolyte layer 23. A theoretical electromotive force of about 1.2 V is generated for each fuel cell 20.

The fine columnar carbon porous body constituting the fuel electrode body 21 may be a porous structure having minute communication holes, and is composed of, for example, a three-dimensional network structure or a point-sintered structure, and includes amorphous carbon and carbon. Carbon composite molded body composed of powder, isotropic high-density carbon molded body, carbon fiber papermaking molded body, activated carbon molded body, etc., preferably, reaction control at the fuel electrode of the fuel cell is easy and reaction From the viewpoint of further improving efficiency, a carbon composite molded body having fine communication holes made of amorphous carbon and carbon powder is desirable.
The carbon powder used for the production of the carbon composite having the porous structure includes highly oriented pyrolytic graphite (HOPG), quiche graphite, natural graphite, artificial graphite, carbon nanotube, At least one (single or a combination of two or more) selected from fullerenes is preferred.

  Further, a platinum-ruthenium (Pt-Ru) catalyst, an iridium-ruthenium (Ir-Ru) catalyst, a platinum-tin (Pt-Sn) catalyst, and the like are present on the outer surface of the fuel electrode body 21. For example, a solution containing a metal fine particle precursor, such as impregnation or dipping treatment, a reduction treatment, a metal fine particle electrodeposition method, or the like.

Examples of the electrolyte layer 23 include ion exchange membranes having proton conductivity or hydroxide ion conductivity, for example, fluorine ion exchange membranes including Nafion (Nafion, manufactured by Du Pont), heat resistance, Good suppression of methanol crossover, for example, a composite membrane using an inorganic compound as a proton conducting material and a polymer as a membrane material, specifically, using a zeolite as the inorganic compound and a styrene-butadiene system as the polymer Examples thereof include a composite film made of rubber, a hydrocarbon-based graft film, and the like.
As the air electrode layer 24, carbon having a porous structure in which platinum (Pt), palladium (Pd), rhodium (Rh) or the like is supported by a method using a solution containing the above-mentioned metal fine particle precursor or the like. A porous body is mentioned.

  The fuel supply body 30 is not particularly limited as long as it is connected to the storage body 10a for storing liquid fuel stored in the fuel storage tank 10 and has a permeation structure capable of supplying the liquid fuel to each unit cell 20. For example, felts, sponges, porous bodies having a capillary force composed of sintered bodies such as resin particle sintered bodies and resin fiber sintered bodies, natural fibers, animal hair fibers, polyacetal resins, acrylics, etc. Bundles made of one or a combination of two or more of resin, polyester resin, polyamide resin, polyurethane resin, polyolefin resin, polyvinyl resin, polycarbonate resin, polyether resin, polyphenylene resin, etc. The porosity of these porous bodies and fiber bundles is appropriately set according to the amount supplied to each unit cell 20. A.

  The spent fuel storage tank 40 is disposed at the end of the fuel supply body 30 via a relay core 40a. The spent fuel storage tank 40 is provided with a relay core 40a made of a porous body and / or a fiber bundle having a capillary force, and the spent fuel is transferred to the spent fuel storage tank 40 through the relay core 40a. As shown in FIGS. 1 (d) and 1 (e), it has an open structure that has an opening 40c that can be discharged and, together with the insertion hole 40b through the relay core 40a, allows the occlusion body 41 to be largely exposed. . Further, in the spent fuel storage tank 40, an occlusion body 41 such as a porous body or a fiber bundle that occludes used fuel is built in contact with the lower end of the relay core 40a. In addition, the rib body 40d can also be provided so that the occlusion body 41 is not dropped.

The liquid fuel supplied by the fuel supply body 30 is used for the reaction in the fuel battery cell 20, and since the fuel supply amount is linked to the fuel consumption amount, it is unreacted and discharged out of the battery. However, unlike the conventional liquid fuel cell, there is no need for a processing system on the fuel outlet side, but liquid fuel that is not used for the reaction is stored in the storage tank 40 when there is an excessive supply due to operating conditions. It has a structure that can be stored in and prevent the inhibition reaction.
In addition, 50 connects the fuel storage tank 10 and the spent fuel storage tank 40, and reliably supplies liquid fuel directly from the fuel storage tank 10 to each of the unit cells 20 and 20 via the fuel supply body 30. It is a member made of a mesh structure or the like.

The fuel cell A according to the present embodiment configured as described above has the liquid fuel occluded in the occlusion body 10a in the fuel storage tank 10 by the permeation structure of the fuel supply body 30 in the fuel cell units 20 and 20 by capillary force. To be introduced.
In the present embodiment, the spent fuel storage tank 40 has an open structure in which an open portion 40 c is provided together with an insertion hole 40 b through the relay core 40 a, and the relay core 40 a is provided at the end of the fuel supply body 30. The used fuel is directly stored in the storage body 41 via the fuel storage tank 10 (storage body 10a), the fuel electrode body 21 and / or the fuel supply body 30 in contact with the fuel electrode body 21, and the relay. The capillary force of the wick 40a and the spent fuel storage tank 40 (occlusion body 41) is determined as follows: fuel storage tank 10 (occlusion body 10a) <fuel electrode body 21 and / or fuel supply body 30 in contact with the fuel electrode body 21 <relay core 40a <By setting it as the spent fuel storage tank 40 (occlusion body 41), the unit cell 20, 20 from the fuel storage tank 10 is kept in any state (angle), upside down, etc. individual Direct liquid fuel can be supplied stably and continuously without causing backflow or disruption, and liquid fuel that is not used for the reaction can be stored in the storage tank 40 to prevent an inhibition reaction. .

In the present embodiment, since the spent fuel storage tank 40 is not sealed, the spent fuel can be released from the storage body 40a into the atmosphere by evaporation. If a small amount of fuel cell is used, the amount of spent fuel is small, and the spent fuel is easily released into the atmosphere by evaporation.
Further, even when a large amount of spent fuel has been discharged, it is possible to hold the amount that can be occluded by the occlusion body 40a, and the occluded spent fuel is sequentially evaporated into the atmosphere. The release is possible by going.

In these embodiments, the spent fuel storage tank 40, the occlusion body 41 in the spent fuel storage tank 40, or the spent fuel storage tank 40 containing the occlusion body 41 may be replaceable. For discharging the spent fuel, the spent fuel storage tank 40 or the occlusion body 41 in the spent fuel storage tank 40 may be discarded as it is. Moreover, the spent fuel occluded in the occlusion body 41 or the relay core 40a may be squeezed out, and the spent fuel may be discharged by centrifugal discharge, evaporation, etc. In this case, the spent fuel storage tank may be reused. Is possible.
Furthermore, in the fuel cell A of this embodiment, since it becomes a structure that can smoothly supply liquid fuel as it is without vaporization without using an auxiliary device such as a pump, a blower, a fuel vaporizer, and a condenser in particular, It becomes possible to reduce the size of the fuel cell.
Furthermore, a fuel supply body 30 having a permeation structure connected directly from the end of the fuel storage tank 10 is connected to the fuel supply to each unit cell 20, 20, so that a fuel cell comprising a plurality of cells Miniaturization can be achieved.

FIG. 2 shows a fuel cell B showing a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the structure similar to the fuel cell A of the said 1st Embodiment, and the description is abbreviate | omitted (same also after 3rd Embodiment).
In the fuel cell B of this embodiment, the liquid fuel is supplied to the fuel supply body 30 via the insertion body 10a, such as a batting, a porous body, or a fiber bundle housed in the fuel storage tank 10, and the relay core 10b. Thus, it is different from the fuel cell A of the first embodiment.
In this embodiment, at least the fuel storage tank 10 (occlusion body 10a), the relay core 10b <the fuel electrode body 21 and / or the fuel supply body 30 in contact with the fuel electrode body 21, the relay core 40a, the spent fuel storage tank 40 ( The capillary force of the occlusion body 41) is determined as follows: fuel storage tank 10 (occlusion body 10a) <relay core 10b <fuel electrode body 21 and / or fuel supply body 30 in contact with the fuel electrode body 21 <relay core 40a <used fuel storage tank By setting 40 (occlusion body 41), no matter what state (angle), inversion, or the like of the fuel cell B than the fuel cell A, the unit cells 20, 20 In this way, liquid fuel can be supplied stably and continuously without causing direct backflow or disruption of the individual liquid fuel, and liquid fuel that is not used in the reaction is stored in the storage tank 40 and inhibits the reaction. Gukoto can.

FIG. 3 (a) shows a fuel cell C showing a third embodiment of the present invention.
In the fuel cell C of this embodiment, as shown in FIG. 3A, the liquid fuel is directly stored, and the fuel is supplied with the collector body 11 provided in the lower part of the fuel storage tank 10 that stores the liquid fuel. Thus, it is different from the fuel cell A of the first embodiment.
In this embodiment, the collector body 11 has the same configuration as a member used in a direct liquid writing instrument or the like, and liquid fuel that is directly stored in the fuel storage tank 10 due to changes in atmospheric pressure, temperature, or the like is excessive in the fuel supply body 30. The liquid fuel that has become excessive due to expansion or the like is held between the collector portions 11a, 11a,... Of the collector body 11, and the pressure in the fuel storage tank 10 is restored when the changes in pressure and temperature are restored. The structure returns to the above and functions in the same manner as in the first embodiment.

3 (b) and 3 (c) show a fuel cell D showing a fourth embodiment of the present invention.
In the fuel cell D of this embodiment, as shown in FIGS. 2B and 2C, the liquid fuel is directly stored, and the fuel cell D is further provided via a valve member 12 below the fuel storage tank 10 containing the liquid fuel. 2 fuel storage tank 15, a porous body or fiber bundle for storing liquid fuel is built in the second fuel storage tank 15, and the fuel supply body 30 is contained in the second fuel storage tank 15. This is different from the fuel cell A of the first embodiment in that the built-in porous body or fiber bundle is connected, and that the unit cell 20 is a flat unit.
In this embodiment, when the fuel storage tank 10 is pressed (knocked), the valve member 12 is opened and closed, and the liquid fuel flows into the second fuel storage tank 15 for temporary storage. As a result, the liquid fuel is supplied to each unit cell 20 by the fuel supply body 30, and the same effect as the first embodiment is exhibited. Furthermore, in this embodiment, the fuel is supplied by knocking the fuel storage tank 10 and can operate as a fuel cell. Therefore, it is possible to easily adjust the supply amount of liquid fuel, adjust the start time of use, and stop using it. it can.

FIG. 4 shows a fuel cell E showing a fifth embodiment of the present invention.
As shown in FIG. 4, the fuel cell E of this embodiment has a cartridge structure in which liquid fuel is directly stored and a fuel storage tank 10 that stores the liquid fuel is replaceable. The fuel supply body has a liquid fuel inflow tank 14 through an outflow valve 13, and further has a second fuel storage tank 15 through a valve member 12 at the lower part of the liquid fuel inflow tank 14. The storage tank 15 contains a porous body or fiber bundle for storing liquid fuel, and the fuel supply body 30 is connected to the porous body or fiber bundle built in the second fuel storage tank 15. And the point that the unit cells 20 are connected in parallel are different from the fuel cell A of the first embodiment.
In this embodiment, when the fuel storage tank 10 is pressed (knocked), the outflow valve member 13 and the valve member 12 are opened and closed, and the liquid fuel flows into the second fuel storage tank 15 for temporary storage. As a result, the liquid fuel is supplied to each unit cell 20 by the fuel supply body 30, and the same effect as the first embodiment is exhibited. Furthermore, in this embodiment, since the fuel storage tank 10 is of a cartridge type, fuel can be easily replenished and replaced, and fuel can be supplied by operating the fuel storage tank 10 to operate as a fuel cell. Adjustment of the start time of use and suspension of use can be easily performed.

FIG. 5 shows a fuel cell F according to a sixth embodiment of the present invention.
The fuel cell F of this embodiment differs from the fuel cell B of the second embodiment in that a lid 42 that can be opened and closed is provided in the spent fuel storage tank 40 as shown in FIG. Is.
As the structure of the lid 42 that can be opened and closed, for example, a screw cap structure, a hinge structure, a fitting cap structure used in a normal writing instrument, or the like is used as long as it does not easily leak used liquid fuel. be able to.
In this embodiment, while functioning similarly to the fuel cell etc. of the said 1st Embodiment, it becomes possible to replace | exchange the occlusion body 41 in the used fuel storage tank 40, and exhaust of used fuel can be performed easily.
Further, the spent fuel storage tank 40 may be removable, and a large used fuel storage tank 40 may be attached as shown in FIG.
Examples of the configuration that allows the spent fuel storage tank 40 to be removable include a screw cap structure, a fitting structure, and a configuration that can be easily attached and detached, such as fixing with a bolt.

FIG. 6 shows a fuel cell G according to a seventh embodiment of the present invention.
In the fuel cell G of this embodiment, as shown in FIG. 6A, the collector body 45 is provided in the spent fuel storage tank 40 around the relay core 40 b that contacts the fuel supply body 30. Only in the point, it is different from the fuel cell of the first embodiment.
The collector body 45 has the same configuration as a member used in a direct liquid writing instrument or the like, and the spent liquid fuel directly stored in the spent fuel storage tank 40 flows back to the fuel supply body 30 due to changes in atmospheric pressure, temperature, or the like. The spent liquid fuel that is likely to flow backward due to expansion or the like is held between the collector portions 45a, 45a,... Of the collector body 42, and returns to the fuel storage tank 40 when the atmospheric pressure and temperature change are restored. It has a structure.

  The material of the collector body 45 is not particularly limited as long as it has storage stability and durability with respect to the liquid fuel to be accommodated, such as metal such as aluminum and stainless steel, polypropylene, polyethylene, polyethylene terephthalate, and the like. Examples include synthetic resins. Particularly preferred are synthetic resins such as polypropylene, polyethylene, and polyethylene terephthalate, which can be produced by ordinary injection molding or stereolithography technology capable of forming complex shapes. In addition, by stacking single sheets obtained by pressing a film of the synthetic resin or the like, a collector body can be configured instead of the collector portion 45a.

  It is important that the surface energy of these collector bodies 45 is set to be higher than the surface free energy of the spent fuel, thereby improving the wettability of the collector body 45 with respect to the spent fuel and maintaining the spent fuel. Power is improved. For the adjustment of the surface free energy of the collector body 45, plasma treatment, ozone treatment, treatment with a surface modifier or the like is usually used.

This embodiment functions in the same manner as the first embodiment, and the capillary force of the relay core 40a is defined as the fuel electrode body 21 and / or the fuel supply body 30 in contact with the fuel electrode body 21 <the relay core 40a. Thus, liquid fuel that is not used for the reaction can be stored in the storage tank 40 without preventing backflow of the spent fuel individually from the spent fuel storage tank 40 to each of the unit cells 20 and 20, thereby preventing an inhibition reaction.
In this embodiment, the spent fuel can be discharged into the atmosphere by evaporating from the open mouth if the amount of spent fuel discharged is small.
Furthermore, when the amount of spent fuel discharged is large, it is possible to open the lid and discharge the spent fuel.
As the structure of the lid 42 that can be opened and closed, in addition to the structure that can be used for the spent fuel storage tank of the fuel cell F of the sixth embodiment, the liquid fuel from the fuel storage tank can be used in the fourth and fifth embodiments. The valve structure mentioned as the outflow mechanism can also be used.

Furthermore, the spent fuel storage tank 40 may be enlarged, and may be further opened by small openings 40d, 40d... As shown in FIG. A lid 42 that can be opened and closed may be provided. For discharging spent fuel, if the amount of spent fuel discharged is small, it can be discharged into the atmosphere by evaporating from the open mouth. In addition, when the amount of spent fuel discharged is large, it is possible to open the lid and discharge the spent fuel.
Further, by setting the surface free energy in the spent fuel storage tank 40 and around the small opening 40d to be lower than that of the spent fuel, the spent fuel accumulated in the spent fuel storage tank 40 is liquid. It is also possible to prevent leakage.
By reducing the surface free energy inside the spent fuel storage tank 40 and around the opening 40d lower than that of the spent fuel, the wet fuel with respect to the spent fuel is reduced, so that the spent fuel is used. This is to make it difficult to leak from the opening.

FIG. 7 shows a fuel cell H according to an eighth embodiment of the present invention.
In this embodiment, the shape of the occlusion body 41 is further increased when the amount of spent fuel exceeding the amount released into the atmosphere from the spent fuel storage tank 40 in each of the above embodiments is expected. It is different from the fuel cells A to G of the above embodiments only in that the spent fuel is easily evaporated.
As shown in FIGS. 7A to 7C, the occlusion body 41 has a fin-like occlusion body in which the occlusion parts 41a are formed at predetermined intervals, and an air layer 41b is formed between the occlusion part 41a and the occlusion part 41a. By providing this, it is possible to evaporate spent fuel into the atmosphere more efficiently.
In addition, the attachment location of the relay core 40a may be on both sides in addition to the central portion.

The fuel cell of the present invention is not limited to the above embodiments, but can be variously modified within the scope of the technical idea of the present invention.
For example, the spent fuel storage tank of the first to sixth embodiments may be replaced with the spent fuel storage tank having the collector body of the seventh embodiment, and the spent fuel storage of the first to seventh embodiments. It is also possible to increase the storage amount of spent fuel by connecting multiple tanks.

(A) is a schematic sectional view showing the fuel cell of the first embodiment of the present invention in a longitudinal section, (b) is a perspective view of the fuel unit cell, (c) is a longitudinal sectional view of the fuel unit cell, (d). Is a perspective view showing an open structure of a spent fuel storage tank, and (e) is a longitudinal sectional view showing an open structure of a spent fuel storage tank. It is a schematic sectional drawing which shows the fuel cell of 2nd Embodiment of this invention in a longitudinal cross-sectional aspect. (A) is a schematic cross-sectional view showing a fuel cell showing a third embodiment of the present invention in a longitudinal cross-sectional aspect, (b) is a schematic cross-sectional view showing a fuel cell showing a fourth embodiment of the present invention in a vertical cross-sectional aspect, (C) is a fragmentary sectional view which shows the attachment structure of a unit cell. It is a schematic sectional drawing which shows the fuel cell which shows 5th Embodiment of this invention in a longitudinal cross-sectional aspect. (A) is a schematic fragmentary sectional view which shows the fuel cell which shows 6th Embodiment of this invention in a longitudinal cross-sectional aspect, (b) is a schematic sectional drawing which shows another form of a spent fuel storage tank. (A) is a schematic fragmentary sectional view which shows the fuel cell which shows 6th Embodiment of this invention in a longitudinal cross-sectional aspect, (b) is a schematic sectional drawing which shows another form of a spent fuel storage tank. It is a fuel cell which shows 7th Embodiment of this invention, and is drawing which shows the occlusion body accommodated in a spent fuel storage tank, (a) is a perspective view, (b) is a top view, (c) is a top view. It is a front view.

Explanation of symbols

A fuel cell 10 fuel storage tank 10b relay core 11 collector body 20 unit cell 30 fuel supply body 40a relay core 40 spent fuel storage tank

Claims (10)

  A plurality of unit cells are formed by constructing an electrolyte layer on the outer surface of the fuel electrode body and constructing an air electrode layer on the outer surface of the electrolyte layer, and liquid fuel is stored in each unit cell. A fuel supply body having an osmotic structure connected to a fuel storage tank is connected to supply liquid fuel, and the end of the fuel supply body is a fuel cell connected to a spent fuel storage tank, and has a capillary force. The spent fuel storage tank is opened in a configuration in which a relay core composed of a porous body and / or a fiber bundle having a spent core is arranged and used fuel is discharged to the spent fuel storage tank via the relay core. A direct methanol fuel cell.   2. The direct methanol fuel cell according to claim 1, wherein the used fuel storage tank is provided with a used fuel storage body made of a porous body and / or a fiber bundle having a capillary force.   3. The direct methanol fuel cell according to claim 1, wherein a capillary force of a relay core of the used fuel storage body is greater than or equal to a capillary force of the fuel supply body.   The direct methanol fuel cell according to any one of claims 1 to 3, wherein a capillary force of the used fuel storage body is greater than or equal to a capillary force of the relay core.   The direct methanol type according to any one of claims 1 to 4, further comprising a collector body in a discharge mechanism that discharges the used liquid fuel to the used fuel storage body into the used fuel storage tank. Fuel cell.   The direct methanol fuel cell according to any one of claims 1 to 5, wherein the collector body is manufactured by injection molding or stereolithography technology, or the collector body is configured by a single-wafer body.   7. The direct methanol fuel cell according to claim 1, wherein a surface free energy of the surface of the collector body is adjusted to be higher than that of the spent liquid fuel.   The direct methanol fuel cell according to any one of claims 1 to 7, wherein the spent fuel storage tank is removable.   The direct methanol fuel cell according to claim 1, wherein the spent fuel storage tank is provided with a lid that can be opened and closed.   A minute opening is provided in the spent fuel storage tank, and the surface free energy around the inner surface of the spent storage tank and the minute opening is adjusted to be lower than that of the spent liquid fuel. Item 10. The direct methanol fuel cell according to any one of Items 1 to 9.

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