JP2003017102A - Fuel supplying device for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supplying device for a fuel cell, using a simple hydrogen supplying method, which can be simply and safely handled. SOLUTION: The fuel supplying device for a cell comprises a cartridge and a capillary tube detachment freely inserted into the cartridge. The cartridge has a raw substance chamber housing raw substance as a fuel, and a reaction chamber housing reactive substance reacting with the raw substance, and the capillary tube has a supplying path guiding the raw substance from the raw substance chamber to the reaction chamber, and an exhausting path exhausting the fuel generated by the reaction from the reaction chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for a fuel cell for supplying hydrogen as a fuel to a polymer electrolyte fuel cell as a power source for a small electronic device or the like. The present invention relates to a fuel supply device for a fuel cell, in which a capillary tube having a double structure has a function of safely supplying hydrogen.

[0002]

2. Description of the Related Art A fuel cell is provided with electrodes on both sides of an electrolyte which is an ionic conductor, one electrode is supplied with an oxidizing gas such as oxygen or air, and the other electrode is a gaseous fuel such as hydrogen or hydrocarbon. Or a liquid fuel such as alcohol is supplied to cause an electrochemical reaction between these electrodes to generate electricity and water.

Although there are various types of fuel cells depending on the type of electrolyte, a liquid electrolyte phosphoric acid fuel cell (PAF) is used.
In a polymer electrolyte fuel cell (PEFC) using C) or a solid polymer electrolyte membrane as an electrolyte, a system for supplying hydrogen produced by externally reforming hydrocarbon as a fuel or hydrogen produced directly in a factory Fuel cells are nearing commercialization.

In particular, since the PEFC can operate effectively at a low temperature and has a high power density, it is highly likely to be put to practical use for power generation for vehicles and power generation for small-scale houses.

A direct methanol fuel cell (DMFC), which directly supplies methanol as a fuel, can use a solid polymer electrolyte membrane as an electrolyte, and therefore has a temperature of 100 ° C.
It is considered to be suitable for small size and portability because it can operate in the following conditions and is easy to transport and store as liquid fuel, and it is a promising power source for future automobiles and mobile electronic devices. Is being watched.

A direct methanol fuel cell (PEM-DMFC) using a solid polymer electrolyte membrane is a fluorine-based polymer membrane partially having a sulfonic acid group, for example, Du
It has a structure in which both sides of a thin film such as a Nafion film manufactured by Pont are sandwiched between porous electrodes carrying a catalyst,
An aqueous methanol solution is directly supplied to the negative electrode, and oxygen or air is supplied to the positive electrode.

In the DMFC, an aqueous methanol solution is directly supplied to the negative electrode and oxygen or air is supplied to the positive electrode,
The oxidation reaction of methanol proceeds due to the action of the catalyst supported on the electrodes.

Platinum (Pt) is particularly excellent as a catalyst for the anode reaction, but the Pt surface of the catalyst is poisoned by CO produced in the oxidation reaction process of methanol.

That is, the adsorption of CO on the surface of Pt reduces the reaction area and deteriorates the battery characteristics.

In order to prevent the catalyst from being poisoned by CO,
By improving the surface structure of Pt, different metals (Ru, Sn, W
Etc.) has been adopted. In particular, Ru dissociates water to form an OH group, which is more likely to be covered with the OH group than Pt, and CO generated when methanol is reformed.
It is often used because it promotes the oxidation of

However, Ru has a lower catalytic activity for methanol than Pt, and it is necessary to raise the reaction temperature to compensate for it. When the reaction temperature is raised, methanol permeates the proton-conducting polymer membrane (Nafion membrane, Dow membrane, Aciplex, Flemion, etc.), which is the electrolyte membrane, from the negative electrode side to the positive electrode. It causes a short circuit phenomenon (crossover) that directly reacts, and reduces the battery performance.

[0012]

In order to use a solid oxide fuel cell as a power source for a portable electronic device, it is safe and easy to handle, like methanol of a direct methanol fuel cell, and it is simple and convenient. A new hydrogen supply method is required.

The present invention has been made in view of the above circumstances, and an object thereof is to use a method for generating and supplying hydrogen which is safe, easy to handle, and simple. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel supply device for a fuel cell, which can prevent the possibility of deterioration of the cell performance to a considerable extent as compared with the prior art.

[0014]

SUMMARY OF THE INVENTION The present invention comprises a cartridge and a capillary tube which is detachably inserted into the cartridge, and the cartridge comprises a raw material chamber for containing a raw material as a raw material for fuel, and a reaction with the raw material. For supplying the raw material to the reaction chamber, and a discharge passage for discharging the fuel generated by the reaction from the reaction chamber. Provide a device.

In the present invention, the capillary tube may be a double tube, and one tube may form the supply path and the other tube may form the discharge path. In this invention, the capillary tube has first and second side holes,
A first side hole communicates with the supply passage from the raw material chamber,
Side holes may communicate with the discharge hole from the reaction chamber.
The present invention may further include a connection pipe that detachably connects the fuel supply port of the solar cell and the discharge passage.

That is, the fuel supply system according to the present invention is
A connection pipe, a capillary tube, and a cartridge may be provided, and one end of the connection pipe may be connected to the polymer electrolyte fuel cell.

In the fuel supply device according to the present invention, the capillary tube is preferably covered with a water-repellent and abrasion-resistant coating film.

In the fuel supply device configured as described above, when the raw material is, for example, an acid aqueous solution,
It is possible to prevent deterioration of the capillary tube due to acid.

Such a coating film is made of, for example, a film containing a fluoroethylene vinyl ether resin and a blocked isocyanate.

In the fuel supply device thus constructed, the deterioration of the capillary tube can be reliably prevented at a relatively low cost.

In the fuel supply device according to the present invention, it is preferable that the cartridge is provided with an air hole for taking the outside air into the raw material chamber.

In the fuel supply device thus constructed, when the raw material is, for example, an aqueous acid solution,
By the air taken into the raw material chamber through the air holes, the acid aqueous solution passes through the capillary tube and is guided to the reaction chamber, so that the reaction can be easily started.

In the fuel supply device according to the present invention, the air holes are
It is preferably covered with a breathable waterproof cloth.

In the fuel supply device thus constructed, air is introduced from the air holes through the moisture-permeable waterproof cloth, but the acid aqueous solution in the cartridge is prevented from leaking by the waterproof cloth. The safety can be improved.

In the fuel supply device according to the present invention, it is preferable that the moisture-permeable waterproof cloth is covered with a thermoplastic resin cap.

In the fuel supply device thus constructed, when the cartridge is not used, the air holes are closed by covering the cartridge with the cap, so that the evaporation of the acid aqueous solution can be prevented.

In the fuel supply device according to the present invention, the partition walls of the raw material chamber and the reaction chamber of the cartridge are preferably made of thermoplastic resin.

In the fuel supply device having such a structure, the partition wall can be composed of, for example, a thermoplastic resin such as ABS resin used for a sample bottle cap of gas chromatography.

In the fuel supply device according to the present invention, the raw material is an aqueous solution of mineral acid or organic acid, and the reaction material is
It is preferably a metal, a metal oxide or a metal hydroxide.

In the fuel supply device having such a structure, since the raw material and the reactant are easily available, hydrogen can be supplied relatively easily, at low cost, safely and simply. You can

In the fuel supply device according to the present invention, the surface of the reactant is preferably covered with a water-soluble protective film.

In the fuel supply device having such a structure, the reaction of the reactant can be suppressed during the time until the reactant comes into contact with the raw material which is an aqueous solution of mineral acid or organic acid.

In the fuel supply device according to the present invention, the water-soluble protective film is preferably made of polyvinyl alcohol.

In the fuel supply device thus constructed, the water-soluble protective film can be formed relatively easily and at low cost.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to this.

FIG. 1 shows a schematic cross-sectional view of a solid polymer electrolyte fuel cell to which the fuel supply device according to the present invention is connected--a fuel cell having a solid polymer electrolyte used as a power source for small electronic devices. .

The fuel supply device D according to the present invention comprises a connection pipe 15, a capillary tube 16 and a cartridge 17, and one end of the connection pipe 15 supplies fuel to the polymer electrolyte fuel cell 50. It is connected to the mouth 6.

The capillary tube 16 is provided at the other end of the connection pipe 15 so as to project outward. The cartridge 17 is for supplying hydrogen as fuel to the fuel cell 50 safely through the capillary tube 16 and the connection pipe 15.

As shown in FIGS. 3 and 4, the capillary tube 16 is a double tube consisting of an outer tube 161 and an inner tube 162 arranged substantially coaxially inside the outer tube 161.
1 and an inner tube 162, and an outer shell portion 31 which is a space formed between the inner tube 162 and the inner tube 162.

The tip of the capillary tube 16 is
A first side hole 22 that is configured to be sharp and has a closed portion 33 in its inner shell portion 32, and has a middle length portion that is provided in the outer pipe 161 and communicates only with the outer shell portion 31; 16
1 to the inner pipe 162 and a second side hole 23 that communicates only with the inner shell portion 32, and the base end portion has a closed portion (not shown) in the outer shell portion 31, and the connection pipe 15 Has an inner shell portion 32 opening to the inside.

As shown in FIGS. 1 and 2, the cartridge 17 is a cylindrical body having one end open and the other end closed. Inside the cartridge 17, a first partition wall 20 is provided at a position near one end so that the distal end of the capillary tube 16 can be detachably penetrated.
A similar second partition wall 21 is provided at a position closer to the other end by a predetermined distance from the first partition wall 20.

Then, the second partition 21 and the cartridge 17
Raw material chamber 18 which is a space formed between the other end of the
In the first partition 2
In the reaction chamber 19 which is a space formed between 0 and the second partition wall 21, a reaction substance which reacts with the raw material substance to generate hydrogen is accommodated.

The fuel supply device D enables stable operation of the fuel cell 50 at low temperatures.

First, as a method for generating hydrogen, a known method, which utilizes a reaction between an aqueous acid solution and a metal, can be considered.

Specifically, in advance, an aqueous solution of a mineral acid or an organic acid is placed in the raw material chamber 18 of the cartridge 17 in the reaction chamber 19
Capable of holding a specific metal in the capillary tube 1
Insert 6 to the fixed position. As a result, the capillary tube 16 penetrates the first partition wall 20 and the second partition wall 21 and all the first side holes 22 and the second side holes 23 are formed in the reaction chamber 19.
To open. Therefore, the aqueous solution of mineral acid or organic acid stored in the raw material chamber 18 is
Hydrogen is generated by passing through the inside and entering the reaction chamber 19 and reacting with a specific metal, and the generated hydrogen is generated by the fuel cell 50.
Is supplied to.

However, it is necessary to control the ionic reaction in which hydrogen is produced by the acid and the metal, because the reaction is instantaneously terminated.

As a first example thereof, there is a method in which a plurality of metals having different particle diameters or a plurality of metals having different dissolution rates are combined with an acid to sequentially generate hydrogen.

As a second example, there is a method utilizing the fact that even the same kind of metal has different dissolution rates depending on the kind of acid. For example, aluminum dissolves very quickly and in large quantities in nitric acid, but very slowly and only in trace amounts in acetic acid. Therefore, aluminum is first dissolved in nitric acid to generate hydrogen, and when nitric acid is consumed, it is dissolved in acetic acid to generate hydrogen.

As a third example, a water-soluble resin film is applied to a metal, and the dissolution rate is changed by changing the thickness of the film. For example, prepare zinc dust and use it for 5%, 1
When soaked in 0%, 30%, and 50% aqueous polyvinyl alcohol solutions and then dried, the thickness of the polyvinyl alcohol film coating the surface of each particle is different. When these are mixed and an aqueous solution of 1 mol of hydrochloric acid is supplied, the surface of the resin thin particles is first dissolved, and then the surface of the resin thick particles is gradually dissolved to control the rate of hydrogen generation by the acid and the metal. be able to.

These three examples may be appropriately combined and used.

Furthermore, considering the case of interrupting the reaction,
The first partition wall 20 and the second partition wall 21 were made of a thermoplastic resin such as ABS resin used for a sample bottle cap for gas chromatography. As a result, even if the capillary tube 16 is pulled out from the first partition wall 20 and / or the second partition wall 21 during the reaction, those partition walls 2
Due to the high elasticity of 0/21, the pores of the partition wall 20/21 by the capillary tube are minimized, and the exudation of the acid aqueous solution can be prevented.

In this embodiment, in order to introduce the raw material and the produced hydrogen in one capillary tube 16, the capillary tube 16 has a double structure as described above.

With such a double structure, the aqueous solution of the mineral acid or the organic acid contained in the raw material chamber 18 is introduced into the reaction chamber 19 through the outer shell portion 31 of the capillary tube 16 and at the same time, the reaction chamber 19 The hydrogen generated in step 3 is used for the inner shell portion 32 of the capillary tube 16 and the connecting pipe 15.
And is supplied to the inside of the fuel cell 50 through the fuel supply port 6.

When the capillary tube 16 is brought into contact with an aqueous acid solution, at least the contact portion must be acid resistant. Therefore, the surface of the capillary tube 16 is coated with a water-repellent and abrasion-resistant coating agent containing, for example, a fluoroethylene vinyl ether resin and a blocked isocyanate, and deterioration due to acid is prevented.

In addition, when the fuel is supplied, the cartridge 17
As a means for inserting the capillary tube 16 into the cartridge to start the reaction, at the other end of the cartridge 17,
Air holes 24 for taking in outside air into the raw material chamber 18.
To provide.

According to such a structure, the cartridge 1
After inserting the capillary tube 16 into 7, the external air is introduced by opening the air hole 24, the aqueous acid solution in the raw material chamber 18 passes through the capillary tube 16 and is guided to the reaction chamber 19 to start the reaction. It

Further, the air holes 24 are provided with a moisture-permeable waterproof cloth 26.
Covered with. According to such a structure, air is introduced, but it is possible to prevent the acid aqueous solution in the cartridge 17 from leaking, and safety is improved.

Further, the air holes 24 covered with the waterproof cloth 26
As a means for closing, the thermoplastic resin cap 25 is detachably attached to the other end of the cartridge 17. With such a structure, when the cartridge 17 is not used, the air hole 24 is closed by covering the other end of the cartridge 17 with the cap 25, so that the evaporation of the acid aqueous solution can be prevented.

The fuel cell 50 is manufactured as follows. That is, as shown in FIG. 1, first, Du Pon
A Nafion membrane manufactured by T. Co., Ltd. is used as the electrolyte membrane 3, and a pair of porous electrodes 4 attached with 5 g of carbon supporting 10 wt% platinum,
The catalyst-integrated electrolyte membrane obtained by joining 5 on both sides of the electrolyte membrane 3 by hot pressing is formed by a casing (A) 1 and a casing (B) 2 made of acrylic resin as an insulating resin. In order to hold and prevent leakage of hydrogen, air or oxygen, silicone resin (not shown) is placed on the joint surface between the housing (A) 1 and the housing (B) 2 for sealing, and then the bolt 10 is used. Conclude by

If necessary, a current collector (not shown) may be inserted on the negative electrode 4 side and the positive electrode 5 side.

Hydrogen gas serving as a fuel is supplied from the fuel supply port 6 provided in the housing (A) 1 to the negative electrode 4 side. The remaining hydrogen gas fuel inside the fuel cell 50 is discharged from the discharge port 7 provided in the housing (A) 1. Positive electrode 5
On the side, electricity is taken out by supplying air from the air supply port 8 provided in the housing (B) 2.

In order to efficiently take out electricity, an aluminum negative electrode 11 installed in the housing (A) 1 is physically connected to the outside of the negative electrode-side porous electrode 4. One end of a copper spring 12 is connected to 11.

Also on the outside of the positive electrode side porous electrode 5,
Aluminum positive pole 13 installed in case (B) 2
Are physically connected to each other, and one end of a copper spring 14 is connected to the plus electrode 13 so that the single cell fuel cell 5
0 is configured.

In addition to carbon, the base material of the catalyst electrode is not only carbon but also porous material such as carbon paper, carbon molded body, carbon sintered body, sintered metal, foam metal, metal fiber aggregate and the like. It may be used as an electrode by applying a noble metal catalyst to a water-repellent substrate.

As the noble metal catalyst used here, in addition to platinum, gold, palladium and ruthenium can be used as the simple substance or as an alloy for the positive electrode 5 and the negative electrode 4.

One end of the connection pipe 15 is connected to the fuel supply port 6. At the other end of the connection pipe 15,
A stainless steel capillary tube 16 is fixed. This capillary tube 16 has an inner diameter of 0.5.
mm, the outer diameter is 0.8 mm, and the surface is covered with fluoroethylene vinyl ether resin.

Next, the construction of the fuel supply cartridge 17 and its action on the fuel cell will be described in detail with reference to FIGS. 1 and 2.

As shown in FIG. 2, the cartridge 17 is made of acrylic resin, and the inside thereof is divided into a raw material chamber 18 and a reaction chamber 19 by a first partition wall 20 and a second partition wall 21 made of an acid-resistant ABS resin. Has been done. One end of the cartridge 17 is connected to the other end of the connection pipe 15. The other end of the cartridge 17 has a diameter of 1 mm.
5 air holes 24 are provided. In the raw material chamber 18,
For example, 10 ml of 0.1 mol / liter hydrochloric acid is added. Further, 3 g and 2 g of zinc having a particle size of 0.5 mm and 3 mm, for example, are placed in the reaction chamber 19.

As shown in FIG. 1, when the cartridge 17 covered with the cap 25 is connected to the connecting pipe 15, the capillary tube 16 causes the first partition wall 20 and the second partition wall 20.
Since it penetrates the partition wall 21, external air enters the raw material chamber 18 through the air holes 24 by removing the cap 25 thereafter. Then, the aqueous hydrochloric acid solution enters the capillary tube 16.

The hydrochloric acid aqueous solution contained in the capillary tube 16 flows out from the first side hole 22 thereof, enters the reaction chamber 19, and reacts with zinc in the reaction chamber 19. Hydrogen generated by the reaction between the hydrochloric acid aqueous solution and zinc passes through the inside of the capillary tube 16 from the second side hole 23 of the capillary tube 16, passes through the connection pipe 15, and is introduced into the negative electrode 4 of the fuel cell 50, where power generation is performed. Get up.

The reaction in the reaction chamber 19 in this case can be expressed by the following chemical reaction formula. For other metals and acids,
Hydrogen is generated although there is a difference in reaction rate. Zn + 2HCl → ZnCl ₂ + H ₂

Hydrogen generated by the reaction in the reaction chamber 19 is guided to the connection pipe 15 through the second side hole 23 of the capillary tube 16 and supplied from the fuel supply port 6 to the negative electrode 4.

This hydrogen is ionized by a noble metal catalyst such as Pt attached to the porous electrode of the negative electrode 4 to generate a proton. H ₂ → 2H ⁺ + 2e ^- This proton conducts the polymer electrolyte and reacts with oxygen ions on the positive electrode 5 side to become water. O ₂ → 2O ² − − 4e ⁻ 2H ⁺ + O ^{2 −} → H ₂ O It is possible to use it as electricity by conducting the electrons in this period to the outside of the battery system. The open circuit voltage at this time is about 0.8
V.

The capillary tube 1 was used during the reaction.
Even if 6 is pulled out, the holes of the first partition wall 20 and the second partition wall 21 formed by the capillary tube 16 are closed by the elasticity of the ABS resin, which is the material of these partition walls 20 and 21, so that the acid aqueous solution is left in the reaction chamber 19. The reaction stops completely.

Next, as a reference example, a direct methanol fuel cell in which methanol was directly supplied was prepared.

This direct methanol fuel cell is
We used a cartridge tube consisting of only one chamber and a simple structure without any double structure. Inject 70% aqueous methanol solution into the cartridge,
It was supplied to the fuel cell. The open circuit voltage at this time is about 0.3V
Met.

From the above, it is understood that hydrogen fuel is suitable for the small fuel cell, and the present invention enables safe and simple hydrogen supply.

In the present embodiment, the fuel supply capillary tube is connected to the fuel cell, but the capillary tube may be installed in the fuel cell.

[0079]

In the fuel supply device of the present invention, when the capillary tube is inserted into the cartridge when the fuel needs to be supplied to the fuel cell, the raw material enters the reaction chamber through the capillary tube. As a result, the generated fuel is discharged through the capillary tube and supplied to the fuel cell. Further, the supply can be stopped by removing the capillary tube from the cartridge. Therefore, it is possible to easily supply and stop the fuel with a device that is easy to handle and safe.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a state in which a fuel supply device according to an embodiment of the present invention is connected to a polymer electrolyte fuel cell.

FIG. 2 is a schematic cross-sectional view of a cartridge that constitutes the fuel supply device of FIG.

FIG. 3 is an enlarged perspective view of a distal end portion of a capillary tube which constitutes the fuel supply device of FIG.

FIG. 4 is an enlarged schematic cross-sectional view of a distal end portion of a capillary tube which constitutes the fuel supply device of FIG.

[Explanation of symbols]

1 case (A) 2 housing (B) 3 Electrolyte membrane 4 Negative electrode (porous electrode) 5 Positive electrode (porous electrode) 6 Fuel supply port 7 Fuel outlet 8 Air supply port 9 Air outlet 10 volts 11 Metal negative pole 12 metal springs 13 metal plus pole 14 Metal spring 15 Connection pipe 16 capillary tubes 17 cartridges 18 Raw material chamber 19 Reaction chamber 20 First partition 21 second partition 22 First side hole 23 Second side hole 24 air holes 25 caps 26 Breathable waterproof cloth

Continued front page    (72) Inventor Mutsuko Komoda             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Kazuhito Nishimura             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F-term (reference) 4G040 EA02 EB04 EB46                 5H026 AA06 AA08                 5H027 AA06 AA08 BA13

Claims (13)

[Claims] 1. A cartridge and a capillary tube removably inserted into the cartridge, the cartridge including a raw material chamber for containing a raw material as a raw material of a fuel, and a reaction chamber for containing a reactive material that reacts with the raw material. And a capillary tube having a supply passage for introducing the raw material from the raw material chamber to the reaction chamber, and a discharge passage for discharging the fuel generated by the reaction from the reaction chamber. 2. The fuel supply device according to claim 1, wherein the capillary tube is a double tube, and one tube forms the supply passage and the other pipe forms the discharge passage. 3. The capillary tube has first and second side holes, the first side hole communicates from the raw material chamber to the supply passage, and the second side hole from the reaction chamber to the discharge hole. The fuel supply device according to claim 2, which is in communication with the fuel supply device. 4. The fuel supply device according to claim 1, further comprising a connection pipe detachably connecting the fuel supply port of the solar cell and the discharge passage. 5. The fuel supply device according to claim 1, wherein the capillary tube is covered with a water-repellent and wear-resistant coating film. 6. The coating film is formed of a film containing a fluoroethylene vinyl ether resin and a blocked isocyanate.
The fuel supply device described in 1. 7. The fuel supply device according to claim 1, wherein the cartridge is provided with an air hole for taking in outside air into the raw material chamber. 8. The fuel supply device according to claim 7, wherein the air holes are covered with a moisture-permeable waterproof cloth. 9. The fuel supply device according to claim 8, wherein the moisture-permeable waterproof cloth is covered with a cap made of a thermoplastic resin. 10. The fuel supply device according to claim 1, wherein the partition walls of the raw material chamber and the reaction chamber are made of a thermoplastic resin. 11. The fuel supply apparatus according to claim 1, wherein the raw material is an aqueous solution of a mineral acid or an organic acid, and the reaction material is a metal, a metal oxide or a metal hydroxide. 12. The fuel supply device according to claim 11, wherein the reactant has a surface covered with a water-soluble protective film. 13. The fuel supply device according to claim 12, wherein the water-soluble protective film is made of polyvinyl alcohol.