JP3360349B2 - Fuel cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly, to a fuel cell for generating electricity by reforming a fuel, and to a fuel cell with less air pollution.

[0002]

2. Description of the Related Art As a prior art, there is known a fuel cell in which hydrogen is used as a reducing agent, oxygen is used as an oxidizing agent, and a current is taken out to the outside.

FIG. 6 is a configuration diagram schematically showing a conventional fuel cell (single cell). Referring to FIG. 6, this fuel cell 600 includes a negative electrode 608, an electrolyte layer 601 and a positive electrode 60.
9 inclusive. The negative electrode 608 and the positive electrode 609 are
1 are provided at the center so as to face each other. The negative electrode 608 is provided so that the surface thereof is in contact with the electrolyte layer 601, and the positive electrode 609 is provided with the electrolyte layer 601.
Is provided so that the surface thereof contacts. Each of the negative electrode 608 and the positive electrode 609 is formed of a porous member such as carbon. The negative electrode 608 and the positive electrode 609 each include a catalyst such as platinum. As the electrolyte layer 601, for example, a cation exchange membrane is used.

An anode active material is continuously supplied to the anode 608 from the outside, and a cathode active material is continuously supplied to the cathode 609 from the outside.

A fuel (reducing agent) is used as the negative electrode active material, and an oxidizing agent is used as the positive electrode active material. Further, the reaction product generated in the fuel cell 600 is configured to be removed from the cell without delay.

As the fuel (reducing agent), for example, hydrogen is used, and as the oxidizing agent, for example, oxygen is used.

Next, the operation of the fuel cell 600 (the principle of power generation)
Will be described below using a hydrogen-oxygen based fuel cell using a cation exchange membrane as the electrolyte layer 601 as an example.

First, an external load circuit 604 having an external load 605 is connected between the negative electrode 608 and the positive electrode 609. Then, the following reaction occurs in the negative electrode 608,
Hydrogen ions (H ⁺ ) are generated, and electrons are released to the external load circuit 604.

[0009]

## STR1 ## H ₂ → 2H + ⁺ 2e ^- On the other hand, the positive electrode 609, electrons of oxygen has passed through an external load circuit 604, and has passed through the cation exchange membrane H
⁺ Produces water by the following reaction.

[0010]

2H ⁺ + 2e ⁻ + ／ O ₂ → H ₂ O At this time, about 1 V is applied between the negative electrode 608 and the positive electrode 609.
Is obtained.

Meanwhile, in a fuel cell of a practical level, the above-mentioned fuel cell (single cell) is used in order to increase the generated voltage.
Are stacked in series for several tens to several hundreds.

[0012] Further, it is preferable that hydrogen serving as a fuel be pure hydrogen in order to facilitate the above-mentioned electrode reaction.

However, hydrogen is generally expensive, and it is necessary to use a high-pressure tank or a hydrogen storage alloy to store hydrogen. Therefore, a fuel cell that stores hydrogen externally and uses the stored hydrogen as a fuel (reducing agent) has a problem in that the manufacturing cost and running cost of the fuel cell increase.

As a technique for solving such a problem, there is an invention described in Japanese Patent Application Laid-Open No. 4-129173. The fuel cell described in Japanese Patent Application Laid-Open No. 4-129173 is provided with a reformer for extracting hydrogen from natural gas and the like and water, and a power generation unit for generating power using the hydrogen extracted by the reformer. .

FIG. 7 is a sectional view schematically showing a main part of a fuel reformer described in Japanese Patent Application Laid-Open No. 4-129173. Referring to FIG. 7, this reformer 700 includes a reforming reaction tube 701 and a hydrogen separation tube 702 disposed inside reforming reaction tube 701. Reforming reaction tube 701 and hydrogen separation tube 70
2 is filled with a reforming catalyst 704 such as Ni. In addition, the hydrogen separation tube 702
Is formed by forming a palladium thin film on a porous metal tube. For example, methane (CH ₄ ) and water (H ₂ O) are supplied to the gap 703. In the reforming reaction tube 701,
The following reactions occur.

[0016]

CH ₄ + H ₂ O → CO + CO ₂ + H ₂ O + H _{2 The} generated hydrogen (H ₂ ) is taken out into a hydrogen separation tube 702, and water (H ₂ O), CO, CO _{2 and the} like are removed from the atmosphere. To be released to

Referring to FIG. 6 and FIG.
Hydrogen taken out in 02 is sent to the negative electrode 608 and used for power generation.

The fuel cell described in Japanese Patent Application Laid-Open No. 4-129173 has a structure in which a power generation section of the fuel cell includes CH ₄ , C
_It has the advantage of having pure hydrogen (H ₂ ) obtained by fuel reforming from fuels such as ₂ H ₆ , C ₃ H ₈ , CH ₃ OH, etc., and enabling efficient power generation.

As described above, conventionally, for the purpose of reducing the manufacturing cost and running cost of a fuel cell,
A reformer is provided as a device for generating hydrogen from natural gas, alcohol, or the like. The reformer reforms natural gas, alcohol, or the like to generate hydrogen, and performs power generation using the generated hydrogen. Various fuel cells have been proposed.

The conventional hydrogen generating method performed in the reformer includes a steam reforming method in which steam is added to a raw material gas to convert the raw material hydrocarbon into hydrogen, carbon monoxide, and carbon dioxide; Partial oxidation (partial combustion) to burn part and obtain hydrogen, carbon monoxide and carbon dioxide
There is a law.

If hydrocarbons are generally represented by C _n H _m , the reactions occurring in the steam reforming process can be shown as the following reactions.

[0022]

Embedded image C _n H _m + nH ₂ O → nCO + (n + m / 2) H ₂ Similarly, if a hydrocarbon is generally represented by C _n H _m ,
The reaction occurring in the partial oxidation method can be shown as the reaction shown below.

[0023]

Embedded image in _{C n H m + n / 2O} 2 → nCO + m / 2H 2 These reactions, some of the carbon monoxide undergoes the following reactions, these reactions proceed by maintaining the equilibrium.

[0024]

Embedded image CO + H ₂ O → CO ₂ + H ₂

[0025]

## STR7 ## The reaction represented by CO + 3H ₂ → CH ₄ + H ₂ O 4 is an endothermic reaction, and the other reactions are exothermic reactions. Therefore, in the reaction shown in Chemical formula 4, external heating is required, and the reaction is usually performed at a temperature of 800 ° C. to 900 ° C. in a heat-resistant metal reaction tube filled with a nickel-based catalyst. On the other hand, at such a temperature,
The reactions of Chemical Formulas 6 and 7 do not proceed to the right, for example, in the case of the reaction at 850 ° C., the concentration of carbon dioxide is 1
3% to 14%, and the concentration of methane is 3% to 4%.

When methanol, which is a kind of alcohol, is used instead of hydrocarbon, the reforming proceeds by reaction with water as shown in the following formula.

[0027]

Embedded image CH_ThreeOH + nH_TwoO → (1-n) CO + nH
_TwoO + nCO_Two+ (2 + n) H _Two However, the reaction represented by O <n <1 is 0 kg / cm^Two~ 20kg / c
m^TwoPressure, set to a temperature between 200 ° C and 600 ° C
Is preferred.

[0028]

After performing the above reaction, the gas leaving the reformer contains a considerable concentration of carbon monoxide.

For this reason, carbon monoxide contained in the gas exiting the reformer may poison the fuel cell catalyst and the like, and may interfere with the normal cell reaction.

Therefore, in order to reduce the residual amount of carbon monoxide, a device called a carbon monoxide converter is used to push the reaction shown in Chemical formula 6 to the right. In the carbon monoxide converter, first, the reaction temperature is set to about 350 ° C. to 370 ° C. in order to promote the reaction shown in Chemical formula 6, which is an exothermic reaction.
In order to increase the reaction rate, so-called high temperature conversion (Hot Shift) is performed using an iron-chromium type catalyst or the like.
A low-temperature conversion (Cold Shift) is performed at about 30 ° C. Thereby, the concentration of carbon monoxide can be reduced.

On the other hand, when the fuel is alcohol, after this reforming reaction, CO in the reformed gas is further reduced.
An O shift catalyst is used. As a CO shift catalyst,
An iron-chromium catalyst, a copper-zinc catalyst, or the like is used. In the CO shift process, the concentration of CO is reduced to about 1% by the reaction of CO with H ₂ O.
Further, in order to further reduce the CO concentration, it is possible to reduce the CO concentration to 100 ppm by further reacting the reformed gas with air by the second CO reduction device. However, such a method has a problem that the apparatus itself is complicated and requires a high temperature. In particular, when such a fuel cell is used in an electric vehicle or the like, there is a problem that the system becomes large.

The present invention has been made in order to solve the above-mentioned problems, and it has been made possible to convert carbon monoxide (C) from fuel without using a complicated flow system as described above.
O) can be generated with almost no generation of hydrogen gas, and power can be generated using the generated hydrogen gas.
An object is to provide a compact fuel cell.

[0033]

[0034]

[0035]

Fuel cell according to [SUMMARY for the present invention includes a first electrode made of a material containing a catalyst, provided in contact with the surface of the first electrode, the first with a cation exchange capacity An electrolyte layer, a second electrode provided to be in contact with the surface of the first electrolyte layer and made of a material containing a catalyst;
A fuel supply means for supplying fuel to the first electrode, a third electrode made of a material containing a catalyst, provided in contact with the surface of the third electrode, the second having a cation exchange capacity 2
And a fourth electrode provided so as to be in contact with the surface of the second electrolyte layer and made of a material containing a catalyst, and means for supplying a reducing agent generated at the second electrode to the third electrode And provided between the second electrode and the third electrode;
Means for supplying a current and oxidant supply means for supplying an oxidant to the fourth electrode are provided, and the current is extracted from the first and fourth electrodes.

The fuel cell according to the present invention is preferably
A reducing agent generated in the second electrode means for supplying to the third electrode, and is provided between the second electrode and the third electrode, means for conducting current, same conductive porous It is formed of a quality member.

Note that the porous member includes a communicating hole that communicates the surface on one side with the surface on the other side.

Further, in the fuel cell according to the present invention, preferably, the fuel contains at least methanol and water, and the reducing agent contains hydrogen.

The term "electrode" used in the present specification means a fuel electrode, a counter electrode, an electrode composed of a combination of a fuel electrode and a separator, and an electrode composed of a combination of a counter electrode and a separator. Including.

[0040]

The operation mechanism of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram showing an example of a reducing agent generating means for generating a reducing agent by electrochemically decomposing a fuel used in the fuel cell according to the present invention. Referring to FIG. 2, this reducing agent generation device 200
Includes a first electrode 208, an electrolyte layer 201 having a cation exchange ability, and a second electrode 209.

As the electrolyte layer 201 having a cation exchange ability, for example, a cation exchange membrane made of a solid polymer electrolyte is used.

The first electrode 208 includes, for example, a porous fuel electrode 202 carrying a platinum catalyst, and a conductive separator 206.

The second electrode 209 includes, for example, a porous counter electrode 203 carrying a platinum catalyst, and a conductive separator 207.

One surface 202a of the fuel electrode 202
Is provided so as to be in contact with one surface 201 a of the electrolyte layer 201.

One surface 203a of the counter electrode 203
Is provided to be in contact with the other surface 201b of the electrolyte layer 201.

The joined body in which the fuel electrode 202 and the counter electrode 203 are combined so as to face each other with the electrolyte layer 201 at the center is composed of a separator 206 and a separator 207.
It is pinched by.

On a surface 206a of the separator 206 on the side in contact with the fuel electrode 202, a plurality of fuel supply and CO _{2 are} provided as means for supplying fuel and discharging reaction products.
A discharge groove 206h is formed.

A plurality of hydrogen (H ₂ ) discharge grooves 2 are formed on the surface 207a of the separator 207 on the side in contact with the counter electrode 203.
07h is formed.

The fuel electrode 202 is supplied with fuel from outside. An external circuit 204 is electrically connected to the fuel electrode 202 and the counter electrode 203 via a separator 206 and a separator 207, respectively.

The external circuit 204 is provided with a DC power supply 205 as a means for applying a voltage so that the first electrode 208 has a positive polarity and the second electrode 209 has a negative polarity. The fuel electrode 202 is a positive electrode, and the counter electrode 20
3 is a negative electrode.

In the above-described reducing agent generator 200,
Water or water vapor is supplied to the fuel electrode 202 together with methanol as a fuel, and a voltage is applied through an external circuit 204 so as to extract electrons from the fuel electrode 202.
As a result, the following reaction proceeds at the fuel electrode 202.

[0053]

Embedded image The hydrogen ions generated at the fuel electrode 202 pass through the cation exchange membrane, and are converted as follows at the counter electrode 203. CH ₃ OH + 2H ₂ O → CO ₂ + 6e ⁻ + 6H ⁺

[0054]

6H ⁺ + 6e ⁻ → 3H ₂ By such a process, hydrogen can be selectively generated on the counter electrode 203 side. Further, as is apparent from the reaction formula shown in Chemical formula 9, since almost no CO is generated in this reaction, the concentration of carbon monoxide can be kept at an extremely low level.

Next, the action mechanism of the power generating means for generating power using the reducing agent generated by the reducing agent generating means will be described with reference to the drawings.

FIG. 3 is a schematic diagram showing an example of a power generating means used in the fuel cell according to the present invention, which generates power using the reducing agent generated by the reducing agent generating means. With reference to FIG.
Electrode 308 and electrolyte layer 30 having cation exchange ability
1 and a fourth electrode 309.

As the electrolyte layer 301 having a cation exchange ability, for example, a cation exchange membrane made of a solid polymer electrolyte is used.

The third electrode 308 includes, for example, a porous fuel electrode 302 supporting a platinum catalyst, and a conductive separator 306.

The fourth electrode 309 includes, for example, a porous counter electrode 303 carrying a platinum catalyst, and a conductive separator 307.

One side surface 302a of fuel electrode 302
Is provided so as to be in contact with one surface 301a of the electrolyte layer 301.

One surface 303a of counter electrode 303
Is provided so as to be in contact with the surface 301 b on the other side of the electrolyte layer 301.

The assembly in which the fuel electrode 302 and the counter electrode 303 are combined so as to face each other with the electrolyte layer 301 at the center is sandwiched between the separator 306 and the separator 307.

The separator 306 contacts the fuel electrode 302.
The fuel (H) _TwoTo supply)
As a means, a plurality of 306h are formed.

The surface 307a of the separator 307 on the side in contact with the counter electrode 303 is provided with a plurality of oxygen supply and H ₂ O
A discharge groove 307h is formed.

The fuel electrode 302 is supplied with hydrogen generated by the above-described reducing agent generator 200. Further, oxygen (O ₂ ) is supplied to the counter electrode 303 from the outside.

The fuel electrode 302 and the counter electrode 303
An external load circuit 304 having an external load 305 is connected via a separator 306 and a separator 307, respectively. Then, in the fuel electrode 302, a current flows so as to extract electrons from the fuel electrode 302, and the following reaction proceeds in the fuel current 302.

[0067]

H ₂ → 2H ⁺ + 2e ⁻ On the other hand, at the counter electrode 303, the following reaction proceeds.

[0068]

2H ⁺ + 2e ⁻ + と な り H ₂ O → H ₂ O At this time, the fuel electrode 302 functions as a negative electrode, and the counter electrode 303 functions as a positive electrode.

[0069]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited by the following examples.

Embodiment 1 FIG. 1 is a configuration diagram schematically showing an embodiment of a fuel cell for reference .

Referring to FIG. 1, this fuel cell 100 includes:
It includes a reducing agent generation device 200 and a power generation device 300.

The reducing agent generating device 200 is the same as the reducing agent generating device 200 shown in FIG.

The power generation device 300 is the same as the power generation device 300 shown in FIG.

Referring to FIG. 1, FIG. 2 and FIG. 3, the reducing agent generated at counter electrode 203 is supplied through reducing agent supply line 25.
By 0, it is supplied to the fuel electrode 302.

In this embodiment, the reducing agent generator 20
0 and the counter electrode 203
It was formed as follows.

First, as the electrolyte layer 201, a cation exchange membrane (trade name: NAFION) made of a solid polymer electrolyte membrane
117 ^R (manufactured by DuPont) was prepared.

Next, as a metal salt, a 3% chloroplatinic acid solution,
After using a 1% NaBH ₄ solution as a reducing agent and allowing the reducing agent to permeate the cation exchange membrane, the surface of the cation exchange membrane was brought into contact with a chloroplatinic acid solution to deposit a platinum layer. By this method, a porous platinum catalyst layer was formed on the surface of the cation exchange membrane to form a pair of electrodes.

Further, in the present embodiment, the power generator 30
0, and the counter electrode 303
It was formed as follows.

As a base material of the fuel electrode 302 and the counter electrode 303, a porous base material of conductive carbon: PTFE (polytetrafluoroethylene) = 3: 7 was prepared. Next, as a catalyst, 5 mg /
Loaded with a mass of cm ² . As the electrolyte layer 301, a cation exchange membrane (trade name: NAF) made of a solid polymer electrolyte membrane
ION117 using ^R (manufactured by DuPont)).

Next, a methanol-water mixed solution having a molar ratio of methanol: water = 1: 2 is supplied to the fuel electrode 202 constituting the reducing agent generator 200 of the fuel cell 100, and the reducing agent generator The temperature of the cells constituting 200 is 30
Set to ° C. Then, the fuel electrode 202 side is defined as a positive electrode, and 0.
When a voltage of 2 V was applied, a current of 1.0 mA / cm ² flowed, and CO ₂ was discharged from the fuel electrode 202 to the counter electrode 20.
3 generated hydrogen gas. No carbon monoxide was detected in the generated hydrogen.

Next, the hydrogen generated from the reducing agent generator 200 is supplied to the power generator 3 using the reducing agent supply pipe 250.
00 was supplied to the fuel electrode 302.

Water generated by reducing agent generator 200
Element to the fuel electrode 302 and oxygen to the counter electrode 303.
When the power was supplied, the power generation device 200 provided 1.0 mA /
cm ^Two, 0.9V.

As a result, at a current value of 1 mA / cm ² ,
When the voltage of 0.2 V required by the reducing agent generation device 200 is subtracted from the output voltage of 0.9 V output from the power generation device 300, 1 mA / cm ² ,
An output voltage of 0.7 V was obtained.

In this embodiment, the reducing agent generator 200
Although the example in which the external power supply 205 is provided is shown, the power generation device 300 may be used as such an external power supply 205.

Embodiment 2 FIG. 4 is a configuration diagram schematically showing one embodiment of a fuel cell according to the present invention.

Referring to FIG. 4, this fuel cell 400 includes:
Separator 421, porous current collecting layer 406, fuel electrode (methanol electrode) 402, cation exchange membrane layer 401, counter electrode (hydrogen generating electrode) 403, porous current collecting layer 420,
Fuel electrode (hydrogen electrode) 412, cation exchange membrane layer 41
1. Counter electrode (oxygen electrode) 413, Porous current collecting layer 417
And the separator 422 are sequentially stacked in this order so as to be in contact with each other.

The separator 421 and the separator 422
Have terminals 423 and 42 for connection to an external load circuit.
4 are provided.

The fuel electrode 402 of the porous current collecting layer 406
The surface 406a on the side in contact with is provided with a plurality of fuel supply and C as means for supplying fuel and discharging reaction products.
An O ₂ discharge groove 406h is formed.

The surface 420a of the porous current collecting layer 420 on the side in contact with the counter electrode 403 is provided with a plurality of hydrogen discharging grooves 420.
ha is formed.

The fuel electrode 412 of the porous current collecting layer 420
A plurality of hydrogen supply grooves 42 are provided on the surface 420b
0hb is formed.

As a means for supplying an oxidizing agent and discharging a reaction product, a plurality of oxygen-supplying and hydrogen-supplying means 417 is provided on a surface 417a of the porous current collecting layer 417 in contact with the counter electrode 413.
_The 2O discharging groove 417h is formed.

The fuel electrode 402 is provided with fuel supply means (not shown) for supplying fuel.

[0093] The counter electrode 413 is provided with an oxidant supply means (not shown) for supplying an oxidant.

[0094] The porous current collecting layer 420 is
20 is made of a porous member having a communicating hole that communicates the surface 420a on one side and the surface 420b on the other side.

Further, the counter electrode 413 includes the counter electrode 41.
Reaction product (H ₂ O) generated in 3 and counter electrode 4
Means (not shown) for discharging the excess oxidant supplied to the fuel cell 13 from the fuel cell 400 is provided.

Next, the operation of the fuel cell 400 will be described below, taking as an example the case where methanol and water are used as the fuel.

First, methanol and water were introduced into the fuel electrode 402, and the fuel electrode 402 was used as a positive electrode.
A voltage is applied so that 03 is a negative electrode.

Then, at the fuel electrode 402, the following reaction proceeds.

[0099]

Embedded image _{CH 3 OH + 2H 2 O →} CO 2 + 6H + + 6e - In H ⁺ is produced the reaction, through the cation exchange membrane 401, in the counter electrode 403, generates and H ₂ as follows .

[0100]

Embedded image 6H ^{+ +} 6e ^- → 3H ₂ generated hydrogen passes through the communicating pores of the current collector layer 420, and reaches the fuel electrode (hydrogen electrode) 412.

Next, oxygen is supplied to the counter electrode (oxygen electrode) 413. Further, the power source applied to the fuel electrode 402 and the counter electrode 403 is removed. Next, the terminal 423 and the terminal 4
24, an external load circuit (not shown) is connected.

Then, at the fuel electrode (hydrogen electrode) 412, electrons are extracted and the following reaction occurs.

[0103]

Embedded image 3H ₂ → 6H ⁺ + 6e ⁻ H ⁺ generated by this reaction passes through the cation exchange membrane 411 and causes the following reaction at the counter electrode (oxygen electrode) 413.

[0104]

Embedded image ^{6H + + 6e - + 2 /} 3O 2 → 3H 2 O or less continuously the methanol and water supplied to the fuel electrode 402, by continuously supplying oxygen to the counter electrode (oxygen electrode) 417 The current can be continuously taken out to the outside.

The following is a more detailed description based on specific data. As the current collecting layers 406, 420, and 417, a porous carbon plate was used.

In this embodiment, the fuel electrode 402 and the counter electrode (hydrogen generating electrode) 403 were formed as follows.

First, as the cation exchange membrane layer 401, a cation exchange membrane made of a solid polymer electrolyte membrane (trade name NA)
FION117 was prepared ^R (manufactured by DuPont)). Next, 3% chloroplatinic acid solution as a metal salt and 1% as a reducing agent
After permeating a reducing agent into the cation exchange membrane using a% NaBH ₄ solution, the surface of the cation exchange membrane was brought into contact with a chloroplatinic acid solution to precipitate a platinum layer. In this way,
A porous platinum catalyst layer was formed on both surfaces of the cation exchange membrane to form a pair of electrodes.

In this example, the fuel electrode (hydrogen electrode) 412 and the counter electrode (oxygen electrode) 413 were formed as follows.

As a base material for the fuel electrode 412 and the counter electrode 413, a porous base material made of conductive carbon: PTFE (polytetrafluoroethylene) = 3: 7 was prepared. Next, as a catalyst, 5 mg /
Loaded with a mass of cm ² .

As the cation exchange membrane layer 411, a cation exchange membrane made of a solid polymer electrolyte membrane (trade name: NAFIO)
N117 using the ^R (manufactured by DuPont)).

Next, the molar ratio is measured on the fuel electrode 402 side.
Supply methanol-water mixture of 1: 1 methanol / water
Then, the temperature of the cell was set to 30 ° C. And the fuel
Positive electrode 402 side, fuel electrode 402 and counter electrode
When a voltage of 0.2 V was applied between the voltage and
mA / cm^TwoCurrent flows from the fuel electrode 402
_TwoHowever, hydrogen gas was generated from the counter electrode 403. Occurred
No carbon monoxide was detected in the hydrogen. This operation
After a certain period of time, oxygen is applied to the counter electrode (oxygen electrode) 413.
Was supplied. Next, the fuel electrode 402 and the counter electrode 403
The voltage applied between and was removed.

Next, the terminals 423 and 424 were connected to an external load circuit (not shown). Hereinafter, by continuously supplying methanol and water to the fuel electrode 402 and continuously supplying oxygen to the counter electrode (oxygen electrode) 413, the current density of the entire fuel cell 400 is 1.0 mA / cm ² . ,
An output voltage of 0.7 V could be continuously taken out.

In this embodiment, a porous base material is used as the current collecting layer 406 and the current collecting layer 417. However, the current collecting layer 406 and the current collecting layer 417 are formed of a dense material. You may.

When a dense material is used for the current collecting layer 406 and the current collecting layer 417, the separator 421 and the separator 422 are not particularly necessary members.

The hydrogen discharging groove 420ha and the hydrogen supplying groove 420hb provided in the current collecting layer 420 are respectively
It should be noted that it may be formed as needed and is not an essential component of the present invention.

In this embodiment, the fuel electrode 402 is
Methanol and water are introduced, and a voltage is applied such that the fuel electrode 402 is a positive electrode and the counter electrode 403 is a negative electrode.
Thereafter, the example in which the fuel cell 400 is started using hydrogen generated at the counter electrode 403 and reaching the fuel electrode 412 and oxygen supplied to the counter electrode 413 has been described. The method is not limited to the activation method described above. The fuel cell 400 may also be started by supplying hydrogen to the fuel electrode 412 from the outside and supplying oxygen to the counter electrode 413, and then introducing methanol and water to the fuel electrode 402.

Embodiment 3 The fuel cell 400 shown in Embodiment 2 is a single cell unit,
Example 4 This single cell unit was stacked in series in four cells.
The same operation as described above was performed.

By the above operation, in the 4-cell in-line type fuel cell shown in Example 3, a current density of 1.0 mA / cm ² and an output voltage of 2.8 V could be continuously taken out.

The disclosure of the above embodiments is merely a specific example of the present invention, and does not limit the technical scope of the present invention.

The electrolyte layer having a cation exchange ability used in the present invention is not particularly limited as long as it selectively allows cations to pass therethrough. Such a cation exchange-capable electrolyte layer is a solid,
Further, it may be a liquid such as an electrolytic solution. When a cation exchange membrane is used as the electrolyte layer having cation exchange ability, for example, a solid polymer electrolyte membrane, a membrane composed of a matrix containing phosphoric acid, a membrane composed of a matrix containing sulfuric acid, a membrane composed of a solid electrolyte, and the like Can be mentioned.
Further, as the cation exchange group, an ion exchange membrane having sulfonic acid, phosphonic acid, sulfate ester, phosphate ester, or the like can be used.

The catalyst used in the present invention is not particularly limited to the following cases.
t), rhodium (Rh), palladium (Pd), ruthenium (Ru), gold (Au), iridium (Ir), or nickel (Ni), cobalt (C
o) and the like. The electrodes are
Platinum (Pt), rhodium (Rh), palladium (P
d), a catalyst material itself such as ruthenium (Ru), gold (Au), iridium (Ir) and an alloy containing at least one of these elements, or a catalyst material for a conductive carbon electrode or the like. May be formed.

The electrode according to the present invention can be formed, for example, by depositing an electrode material in a porous structure on the surface of a cation exchange membrane. In addition, the electrode according to the present invention can be formed, for example, by supporting a catalyst on a porous body that has been prepared in advance by burning or the like.

In the present invention, the fuel supply means includes, for example, a container or tank for storing the fuel for bringing the fuel into contact with one of the electrodes, a pump for feeding the fuel to the container or the tank at a predetermined pressure, or the like. Can be
The invention is not limited thereto, and any mechanism may be used as long as it supplies fuel to the electrode.

The fuel used in the fuel cell according to the present invention includes a fuel containing at least methanol and water.

Further, by stacking a large number of the units shown in the second embodiment in series, it is possible to increase the voltage. FIG.
FIG. 1 is a configuration diagram schematically showing a fuel cell in which many such fuel cells 400 are stacked in series.

Referring to FIG. 5, the power generation section of the fuel cell is configured by stacking a number of fuel cells 400 in series.

Terminals are provided on the current-collecting layer on the fuel supply side and the current-collecting layer on the oxidant-supplying side of the battery cell units at both ends of the fuel cell 400 which is stacked in series. And an external terminal 504 having an external load 505 is connected.

[0128]

As described above, according to the present invention,
No complicated reaction system and flow system as in the prior art is required, and highly pure hydrogen can be produced by a very simple apparatus. According to the present invention, generation of impurities such as CO is suppressed.

Therefore, in the fuel cell according to the present invention, since the generated CO is significantly reduced, a decrease in chemical reactivity due to poisoning of the catalyst is also prevented.

In addition, by stacking a plurality of fuel cells (single cells) according to the present invention in series, it is possible to increase the voltage.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a specific example of a fuel cell referred to as a reference .

FIG. 2 is a configuration diagram schematically showing a specific example of a reducing agent generating device for a fuel cell according to the present invention.

FIG. 3 is a configuration diagram schematically showing one embodiment of a power generation device for a fuel cell according to the present invention.

FIG. 4 is a configuration diagram schematically showing a specific example of a fuel cell according to the present invention.

FIG. 5 is a configuration diagram schematically showing a specific example of a fuel cell in which a plurality of fuel cells (single cells) according to the present invention are stacked in series.

FIG. 6 is a configuration diagram schematically showing a conventional fuel cell.

FIG. 7 is a configuration diagram schematically showing a conventional fuel reformer.

[Explanation of symbols]

100, 400, 500 Fuel cell 200 Reducing agent generator 201, 301, 401, 411 Electrolyte layer 202, 302, 402, 412 having cation exchange ability Fuel electrode 203, 303, 403, 413 Counter electrode 204, 304 504 External circuit 205 Power supply 206, 207, 306, 307, 421, 422 Separator 206h, 406h Fuel supply / CO ₂ discharge groove 207h, 420ha Hydrogen discharge groove 208, 209, 308, 309 Electrode 300 Power generator 305, 505 External load 306h, 420hb Hydrogen supply groove 307h, 417h Oxygen supply / H ₂ O discharge groove 406, 420, 417 Current collecting layer 423, 424 terminal

Claims (3)

(57) [Claims] 1. A first electrode made of a material containing a catalyst, a first electrolyte layer provided in contact with a surface of the first electrode and having a cation exchange ability, and a first electrolyte layer A second electrode provided so as to be in contact with the surface of the first electrode and made of a material containing a catalyst, fuel supply means for supplying fuel to the first electrode, a third electrode made of a material containing a catalyst, wherein provided in contact with the surface of the third electrode, a second electrolyte layer having cation-exchange ability, provided in contact with the surface of the second electrolyte layer, a fourth of a material containing a catalyst and electrodes, and means for supplying a reducing agent generated in the second electrode to the third electrode is provided between the second electrode and the third electrode,
A fuel cell, comprising: means for supplying a current; and oxidant supply means for supplying an oxidant to the fourth electrode, wherein the current is extracted from the first and fourth electrodes. Wherein means for supplying a reducing agent generated in the second electrode to the third electrode, and the second
2. The fuel cell according to claim 1 , wherein the means for supplying a current provided between the third electrode and the third electrode is formed of the same conductive porous member. Wherein the fuel comprises at least methanol and water, and the reducing agent comprises hydrogen, according to claim 1 or
Or the fuel cell according to 2 .