JP2003022829A - Humidification of reaction gas for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide technology, capable of easily controlling moisture content in reaction gas to be supplied to a fuel cell. SOLUTION: A fuel cell system is equipped with a fuel cell 100; a reactant gas passage 352 for passing the reactant gas to be supplied to the fuel cell; and an off-gas passage 354 for passing the off-gas exhausted from the fuel cell. A moisture absorbing-desorbing part 320 is installed midway of the reaction gas passage 352 and midway of the off-gas passage 354, and the moisture absorbing-desorbing part 320 contains a rotating member, which absorbs moisture in the off-gas and discharges the moisture to the reactant gas. The number of revolutions of the rotating member is controlled by a control part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system, and more particularly to a technique for humidifying a reaction gas supplied to a fuel cell.

[0002]

2. Description of the Related Art A fuel cell system includes a fuel cell, a reaction gas passage through which a reaction gas supplied to the fuel cell passes, and an offgas passage through which an offgas discharged from the fuel cell passes. When a polymer electrolyte fuel cell is used as the fuel cell, it is necessary to replenish the water depleted from the electrolyte membrane. Therefore, the reaction gas supplied to the fuel cell is usually humidified.

Conventionally, various methods have been adopted to humidify the reaction gas. For example, a method of humidifying the reaction gas by bubbling is adopted. In addition, a method of arranging a water vapor permeable membrane at the interface between the reaction gas passage and the off gas passage and moving the water vapor in the off gas into the reaction gas to humidify the reaction gas is adopted (Japanese Patent Laid-Open No. 6-132038). Issue).

[0004]

However, when the conventional method is adopted, it is difficult to adjust the amount of water in the reaction gas.

This problem is not limited to the fuel cell system including the polymer electrolyte fuel cell, but is common to other fuel cell systems that humidify the reaction gas supplied to the fuel cell.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a technique capable of easily adjusting the amount of water in the reaction gas supplied to the fuel cell. .

[0007]

In order to solve at least a part of the above-mentioned problems, an apparatus of the present invention is a fuel cell system, which is provided with a fuel cell and the fuel cell. A reaction gas passage through which a reaction gas passes, an off gas passage through which an off gas discharged from the fuel cell passes, and an adsorbing / dehumidifying portion arranged in the middle of both the reaction gas passage and the off gas passage, An absorption / dehumidification unit that includes a rotating member that absorbs water in off-gas and that can release water into the reaction gas; and a control unit that rotates the rotating member and adjusts the rotation speed of the rotating member. ,
It is characterized by including.

In this fuel cell system, an adsorbing / dehumidifying portion including a rotating member capable of absorbing the moisture in the offgas and releasing the moisture into the reaction gas is arranged in the middle of both the reaction gas passage and the offgas passage. Has been done. When the rotation speed of the rotating member is increased, the amount of water in the reaction gas increases, and when the rotation speed of the rotating member is decreased, the amount of water in the reaction gas decreases. Therefore, it is possible to easily adjust the amount of water in the reaction gas supplied to the fuel cell by adjusting the rotation speed of the rotating member.

When the fuel cell uses oxygen gas and hydrogen gas for power generation, the reaction gas may be an oxidizing gas containing oxygen gas or a fuel gas containing hydrogen gas. May be.

In the above apparatus, the control section includes a measuring device used for measuring specific information relating to the amount of water contained in the electrolyte layer of the fuel cell, and the control section uses the information to measure, It is preferable to adjust the number of rotations of the rotating member.

With this, the amount of water contained in the electrolyte layer of the fuel cell can be maintained within an appropriate range, and the fuel cell can perform stable power generation.

In the above apparatus, the control section includes a flow rate adjusting section for adjusting the flow rate of the reaction gas, and the control section controls the rotation rate of the rotating member to fall outside a predetermined range. It is preferable to adjust the flow rate of the reaction gas.

In this way, the amount of water contained in the electrolyte layer of the fuel cell can be kept within an appropriate range even when the rotation speed of the rotating member is out of the predetermined range. The control unit may decrease the flow rate of the reaction gas when, for example, the rotation speed of the rotating member becomes larger than the relatively large first limit value, and the second rotation speed of the rotating member is relatively small. When it becomes smaller than the limit value, the flow rate of the reaction gas may be increased.

In the above apparatus, the information includes the humidity of the reaction gas discharged from the adsorbing / dehumidifying unit, and the control unit keeps the humidity of the reaction gas within a predetermined range. The number of rotations of the rotating member may be adjusted.

When the humidity of the reaction gas is relatively high, the amount of water contained in the electrolyte layer of the fuel cell becomes relatively large,
When the humidity of the reaction gas is relatively low, the amount of water contained in the electrolyte layer of the fuel cell is relatively small. Therefore,
According to the above, the amount of water contained in the electrolyte layer of the fuel cell can be easily kept within an appropriate range.

In the above apparatus, the information includes the output voltage of the fuel cell, and the control unit controls the rotation speed of the rotating member so that the output voltage of the fuel cell is kept within a predetermined range. May be adjusted.

When the amount of water contained in the electrolyte layer of the fuel cell cannot be kept within an appropriate range, the output voltage of the fuel cell changes. Therefore, with the above configuration, the amount of water contained in the electrolyte layer of the fuel cell can be easily kept within an appropriate range.

In the above apparatus, the information is a first amount of water contained in the off gas discharged from the fuel cell, and a second amount of water generated in the fuel cell.
The control unit may adjust the number of rotations of the rotating member such that the difference between the first water amount and the second water amount is maintained within a predetermined range.

When the difference between the amount of water contained in the off gas discharged from the fuel cell (that is, the off gas supplied to the adsorption / dehumidification section) and the amount of water generated in the fuel cell is supplied to the fuel cell. The amount of water contained in the electrolyte layer of the fuel cell is kept almost constant. Therefore, with the above configuration, the amount of water contained in the electrolyte layer of the fuel cell can be easily kept within an appropriate range.

In the above apparatus, the information includes a first amount of water contained in the off gas discharged from the fuel cell, and a second amount of water contained in the off gas discharged from the adsorbing / dehumidifying section. The control unit may adjust the number of rotations of the rotating member such that the difference between the first water amount and the second water amount is maintained within a predetermined range.

The difference between the amount of water contained in the off gas discharged from the fuel cell (that is, the off gas supplied to the adsorption / dehumidification unit) and the amount of water contained in the off gas discharged from the adsorption / dehumidification unit is calculated by It is almost equal to the amount of water contained in the reaction gas discharged from the section. So if you do the above,
The amount of water contained in the electrolyte layer of the fuel cell can be easily kept within an appropriate range.

In the above apparatus, the information includes a first amount of water generated in the fuel cell and a second amount of water contained in the off gas discharged from the adsorbing / dehumidifying portion.
The control unit may adjust the number of rotations of the rotating member such that the difference between the first water amount and the second water amount is maintained within a predetermined range.

When the amount of water produced in the fuel cell and the amount of water contained in the offgas discharged from the adsorbing / dehumidifying portion are substantially equal to each other, the amount of water contained in the electrolyte layer of the fuel cell is kept substantially constant. . Therefore, with the above configuration, the amount of water contained in the electrolyte layer of the fuel cell can be easily kept within an appropriate range.

[0024]

Other Embodiments of the Invention The present invention also includes the following embodiments. That is, the method of the present invention includes a fuel cell, a reaction gas passage through which a reaction gas supplied to the fuel cell passes, an off gas passage through which an off gas discharged from the fuel cell passes, the reaction gas passage and the off gas passage. And an adsorbing / dehumidifying portion disposed in the middle of both passages, the absorbing / dehumidifying portion including a rotating member capable of absorbing the moisture in the off-gas and releasing the moisture into the reaction gas. A method for humidifying the reaction gas in a fuel cell system, comprising the step of rotating the rotating member and adjusting the number of rotations of the rotating member.

Even when this method is used, the same action and effect as when the apparatus of the present invention is used can be obtained, and the amount of water in the reaction gas supplied to the fuel cell can be easily adjusted.

As described above, the present invention provides a fuel cell system,
A device such as a mobile body equipped with a fuel cell system, a method for humidifying a reaction gas in the fuel cell system, a computer program for realizing the function of the method or the device, a recording medium recording the computer program,
It can be realized in various modes such as a data signal including the computer program and embodied in a carrier wave.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION A. First Example: Next, an embodiment of the present invention will be described based on examples. FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system according to the first embodiment of the present invention. This fuel cell system includes a fuel cell 1
00, a fuel gas supply unit 200 that supplies a fuel gas containing hydrogen gas to the fuel cell, and an oxidizing gas supply unit 300 that supplies an oxidizing gas containing oxygen gas to the fuel cell.

The fuel cell 100 is a polymer electrolyte fuel cell that is relatively small and has excellent power generation efficiency. FIG. 2 is an explanatory diagram showing a schematic configuration inside the fuel cell 100. As shown in the figure, the fuel cell 100 is formed by stacking a plurality of single cells (single cells). One unit cell 110 includes an electrolyte membrane 112, an anode (hydrogen electrode) 114a and a cathode (oxygen electrode) 114c, and a pair of separators 116.
Includes and. The electrolyte membrane 112 has two electrodes 114.
It is sandwiched by a and 114c, and further sandwiched by two separators 116 on the outer side. Each separator 116 is arranged so as to separate two adjacent single cells 110. Specifically, each separator 116 has an anode 114 in one of the adjacent single cells.
The cathode 114 in the other single cell while being in contact with a
It is arranged so as to contact with c. Separator 116
A plurality of grooves are formed on both surfaces of the anode 11
4a and the separator 116, and the cathode 11
A plurality of passages 114ap and 114cp are formed between the 4c and the separator 116, respectively. In FIG. 2, the anode side passage 114 ap and the cathode side passage 114 a
The cp and the cp are formed in parallel with each other, but may be formed so as to be orthogonal to each other.

The electrolyte membrane 112 is a cation exchange resin membrane and has good conductivity in a wet state. As the cation exchange resin film, a film formed of a solid polymer material such as a fluorine resin can be used, and for example, a Nafion film manufactured by DuPont can be used. Anode 114a and cathode 114
c is made of a material having sufficient gas diffusivity and conductivity such as carbon cloth woven of carbon fibers, carbon paper, and carbon felt. It should be noted that the interface between each electrode 114a, 114c and the electrolyte membrane 112 is coated with a catalyst for causing the reaction in each electrode 114a, 114c to proceed at a relatively low temperature (about 50 ° C to about 100 ° C). As the catalyst, for example, platinum or an alloy containing platinum can be used. Separator 116
Is formed of a material having sufficient gas impermeability, conductivity and corrosion resistance, such as press-molded carbon and metal.

Fuel gas containing hydrogen gas is supplied from the fuel gas supply unit 200 to the anode side passage 114ap shown in FIG. 2, and oxidizing gas containing oxygen gas is supplied from the oxidizing gas supply unit 300 to the cathode side passage 114cp. Is supplied. Then, the following electrochemical reaction proceeds.

H ₂ → 2H ⁺ + 2e ⁻ (1) (1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2) H ₂ + (1/2) O ₂ → H ₂ O … (3)

Equation (1) shows the reaction at the anode 114a. Hydrogen ions generated at the anode 114a in each unit cell move toward the cathode 114c in the same unit cell through the electrolyte membrane 112. On the other hand, the electrons generated at the anode 114a in each unit cell are separated by the separator 116 from the adjacent unit cell 1.
It moves toward the cathode 114 c inside 10. At this time, in the cathode 114c, the reaction represented by the formula (2) proceeds and water (actually water vapor) is generated. Then, the reaction represented by the formula (3) proceeds in the entire fuel cell. In addition,
The water generated at the cathode 114c is also referred to as "produced water" below.

The fuel gas supply unit 200 (FIG. 1) produces a fuel gas containing hydrogen gas and supplies it to the fuel cell 100. The fuel gas supply unit 200 includes a raw material tank 212, a water tank 214, two evaporators 222 and 224, a fuel gas generation unit 230, a combustion unit 240, and a condenser 250. The raw material tank 212 of this embodiment stores methanol.

The first evaporator 222 is a raw material tank 212.
And the mixed liquid introduced from the water tank 214 is vaporized, and the mixed gas of the raw material and water (hereinafter, referred to as “raw material gas”) is supplied to the fuel gas generation unit 230. The second evaporator 224 vaporizes the water introduced from the water tank 214 and supplies water vapor to the fuel gas generation unit 230.

The fuel gas generation unit 230 includes a reforming unit 232.
And a hydrogen separation membrane 234 and an extraction unit 236. The fuel gas generation unit 230 is integrated, and the hydrogen separation membrane 234 is sandwiched between the reforming unit 232 and the extraction unit 236. The reforming section 232 is supplied with the raw material gas from the first evaporator 222, and the extraction section 236 is supplied with the steam from the second evaporator 224.

In the reforming section 232, the chemical reactions (reforming reactions) shown in the following equations (4) and (5) sequentially proceed to produce a mixed gas containing hydrogen gas. Then, the reforming reaction represented by the equation (6) proceeds in the entire reforming section. Note that the reforming section 232 carries a catalyst for promoting the reforming reaction, and as the catalyst, for example, a CuO—ZnO-based catalyst or a Cu—ZnO-based catalyst can be used.

[0037]     CH₃OH → CO + 2H₂                  … (4)     CO + H₂O → CO₂+ H₂              … (5)     CH₃OH + H₂O → CO₂+ 3H₂        … (6)

The hydrogen separation membrane 234 is formed by selectively permeating hydrogen gas from a mixed gas (ie, raw material gas, carbon monoxide gas, carbon dioxide gas, hydrogen gas, etc.) contained in the reforming section 232. , Hydrogen gas is separated.
In this embodiment, as the hydrogen separation membrane 234, a membrane in which fine metal particles having selective hydrogen permeability are supported on a porous support made of ceramic is used. As the ceramic, for example, alumina, silicon nitride, silica or the like can be used. Moreover, as the metal, palladium, an alloy of palladium and silver, an alloy of lanthanum and nickel, or the like can be used. The hydrogen separation membrane 234 is
It can be produced by impregnating a porous support with a solvent containing metal fine particles and firing it, or by firing a mixture of ceramic fine particles and metal fine particles constituting the porous support. Note that the hydrogen separation membrane 234
May be formed only of a metal having selective hydrogen permeability.

The extraction unit 236 promotes the permeation of hydrogen gas from the hydrogen separation membrane 234 by using the supplied water vapor. That is, the hydrogen gas generated in the reforming section 232 passes through the hydrogen separation membrane 234 according to the hydrogen partial pressure difference between the reforming section 232 and the extraction section 236. Therefore, in this embodiment, the partial pressure of hydrogen in the extraction section 236 is set to be lower than the partial pressure of hydrogen in the reforming section 232 by sequentially supplying steam to the extraction section 236.

Further, in this embodiment, the total pressure of the extraction section 236 is set higher than the total pressure of the reforming section 232. This is to prevent carbon monoxide gas from mixing in the fuel gas obtained in the extraction section 236. That is, when the carbon monoxide gas is mixed in the fuel gas, the catalyst applied to the interface between the anode 114a and the electrolyte membrane 112 in the fuel cell 100 is poisoned by the carbon monoxide gas and stable electricity is generated. The chemical reaction is hindered. However, if the total pressure between the extraction section 236 and the reforming section 232 is set as described above, even if there are pinholes in the hydrogen separation membrane 234, the carbon monoxide gas inside the reforming section 232 will be extracted by the extraction section 236.
Can be suppressed. Further, if steam leaks from the extraction section 236 to the reforming section 232 via the pinhole of the hydrogen separation membrane 234, the leaked steam can be used for the reforming reaction (equation (6)). In addition,
When there are no pinholes in the hydrogen separation membrane 234,
It is preferable to set the total pressure of the reforming section 232 higher than the total pressure of the extraction section 236 to improve the hydrogen gas separation efficiency.

Further, in FIG. 1, the source gas and the steam are shown to flow in the same direction in the reforming section 232 and the extracting section 236, but in reality, they flow in opposition. The hydrogen partial pressure in the reforming section 232 is higher on the downstream side where the reforming reaction is progressing. On the other hand, the hydrogen partial pressure in the extraction section 236 is lower on the upstream side where the hydrogen gas extraction is less progressing. When the flows of the raw material gas and the steam are opposed to each other, the downstream side portion of the reforming section 232 is adjacent to the upstream side portion of the extraction section 236 via the hydrogen separation membrane 234. At this time, the downstream side portion of the reforming section 232 (that is, the extraction section 23
Since the hydrogen partial pressure difference in the upstream portion 6) becomes considerably large, the hydrogen gas can be efficiently separated.

An impermeable gas discharged from the reforming section 232 (that is, a gas that has not permeated the hydrogen separation membrane 234).
Are oxidized in the combustion section 240. Specifically, carbon monoxide gas is oxidized to carbon dioxide gas, and hydrogen gas is oxidized to water vapor. This makes it possible to prevent the carbon monoxide gas contained in the impermeable gas from being released into the atmosphere.

The fuel gas discharged from the extraction section 236 is
It is supplied to the condenser 250. The condenser 250 condenses and removes the water vapor contained in the fuel gas, and then supplies the fuel gas to the fuel cell 100. The condensed water obtained in the condenser 250 is returned to the water tank 214.

The oxidizing gas supply unit 300 (FIG. 1) supplies an oxidizing gas containing oxygen gas to the fuel cell 100. The oxidizing gas supply unit 300 includes a blower 310 and an adsorbing / dehumidifying unit 320.
And a condenser 390.

The blower 310 compresses air (oxidizing gas) and supplies it to the adsorbing / dehumidifying section 320. In the adsorption / dehumidification unit 320,
The oxidizing gas supplied to the fuel cell 100 is introduced, and the oxidizing off gas discharged from the fuel cell 100 is introduced. The adsorption / dehumidification unit 320 transfers moisture between the oxidizing gas and the oxidizing off gas. In particular,
The adsorption / dehumidification unit 320 absorbs moisture (water vapor) in the oxidizing off gas and releases the absorbed moisture into the oxidizing gas to humidify the oxidizing gas. The condenser 390 condenses the water vapor remaining in the oxidation off gas discharged from the adsorption / dehumidification unit 320, and condenses the condensed water into the water tank 2 of the fuel gas supply unit 200.
Supply to 14. Thereby, the condensed water can be used in the fuel gas generation unit 230.

By the way, the oxidizing off-gas immediately after being discharged from the fuel cell 100 contains water vapor produced by the produced water according to the above-mentioned equation (2) and the water deprived from the electrolyte membrane 112. . The electrolyte membrane 112
Water is depleted from the electrolyte membrane 112 due to hydrogen ions.
This is because water molecules in the electrolyte membrane 112 are carried to the cathode 114c side and vaporized when moving inside. Further, by exposing the electrolyte membrane 112 to the flow of oxidizing gas,
This is because water on the surface of the electrolyte membrane 112 is vaporized. The adsorption / desorption unit 320 humidifies the oxidizing gas in order to replenish the moisture depleted from the electrolyte membrane 112.

FIG. 3 is an explanatory view showing the external appearance of the adsorption / desorption unit 320 (FIG. 1). As shown, the adsorption / dehumidification unit 320
Are connected to an oxidizing gas passage 352 through which the oxidizing gas supplied to the fuel cell 100 passes and an oxidizing off gas passage 354 through which the oxidizing off gas discharged from the fuel cell 100 passes. In other words, the adsorbing / dehumidifying portion 320 has the oxidizing gas passage 3
52 and the oxidation off gas passage 354 are arranged in the middle of both passages.

FIG. 4 is a schematic sectional view of the adsorption / desorption unit 320 shown in FIG. 4 (A) and 4 (B) are respectively shown in FIG.
2 shows a cross section of the adsorption / dehumidification unit 320 cut along the dashed-dotted line A in parallel with the yz plane and a cross section taken along the dashed-dotted line B in parallel with the xy plane. As illustrated, the moisture absorbing / dehumidifying unit 320 includes a rotating member 330 and a storage unit 340 that stores the rotating member 330.

The storage portion 340 has a substantially columnar outer shape, and the two bottom surfaces thereof have the oxidizing gas passage 35.
2 and the oxidation off-gas passage 354. Partition plates 341 and 342 for partitioning the inside of the storage unit 340 into two spaces are provided inside the two bottom surfaces of the storage unit 340. The two spaces are each passage 35
It communicates with 2,354. Further, seal members 345 and 346 are provided around the inside of the two bottom surfaces of the storage section 340. The seal member ensures that the oxidizing gas and the oxidizing off gas flowing into each space pass through the rotating member 330.

The rotating member 330 has a substantially columnar outer shape. FIG. 5 is an explanatory diagram showing the outer appearance of the rotating member 330 of FIG. As shown, the rotating member 330 is
A shaft member 332 and a substantially cylindrical water exchange section 334 provided around the shaft member are provided. Moisture exchange section 334
Have a plurality of small passages formed along the shaft member 332 and arranged in a honeycomb shape. Then, the wall surface of each small passage is coated with a moisture absorbing / dehumidifying material capable of absorbing and releasing moisture. The honeycomb member of the water exchange unit 334 can be formed of stainless steel, for example. Further, as the absorbent / dehumidifier, for example, zeolite (zeolite) can be used. Zeolite has hygroscopicity and dehumidifying properties, and has a property of easily absorbing water at a relatively low temperature and easily releasing water at a relatively high temperature.

The rotating member 330 (FIG. 4) is a shaft member 332.
It is stored in the storage portion 340 so as to be rotatable around.
The rotating member 330 rotates when a driving unit such as a motor rotates the shaft member 332 protruding from the storage unit 340. The specific portion of the water exchange unit 334 is arranged in the space communicating with the oxidation off-gas passage 354 at the first time. At this time, this specific portion absorbs the water in the oxidizing off gas. This specific portion is the rotating member 3
At a second time after the rotation of 30, it is arranged in the space communicating with the oxidizing gas passage 352. At this time, this specific part humidifies the oxidizing gas by releasing the moisture absorbed at the first time into the oxidizing gas. In this way, the moisture exchange unit 334 can absorb the moisture in the passing oxidizing off gas and release the moisture into the passing oxidizing gas.

The water exchange section 334 of this embodiment also has a function as a heat exchange section. That is, the moisture exchange unit 334 stores the heat of the oxidation offgas when absorbing the moisture (water vapor) in the oxidation offgas. Then, the moisture exchange unit 334, when releasing moisture into the oxidizing gas,
The stored heat is given to the oxidizing gas. The water exchange unit 334
The heat that is stored includes sensible heat associated with the temperature change of water vapor and latent heat associated with the phase change of water vapor into water. By using such a water exchange unit 334, the efficiency of the fuel cell system can be improved, and it is not necessary to separately provide a heating unit for heating the oxidizing gas to a temperature suitable for the electrochemical reaction in the fuel cell 100. There is an advantage. of course,
You may make it provide a heating part.

FIG. 6 is a graph schematically showing the relationship between the humidification amount Wh of the oxidizing gas by the adsorption / desorption unit 320 and the output voltage of the fuel cell 100. Here, the humidification amount Wh of the oxidizing gas
(Mol / min) is the amount of water contained in the oxidizing gas discharged from the adsorption / desorption unit 320 per unit time.

As shown in the drawing, when the humidifying amount Wh of the oxidizing gas is appropriate, in other words, when the humidifying amount Wh of the oxidizing gas is included in Wh1 to Wh2 in the figure, the fuel cell 1
The output voltage of 00 is kept almost constant. However,
When the humidifying amount Wh of the oxidizing gas is not appropriate, that is, when the humidifying amount Wh of the oxidizing gas is smaller than the first limiting humidifying amount Wh1 and is larger than the second limiting humidifying amount Wh2, the output voltage of the fuel cell 100. Is reduced. This is because when the humidification amount Wh is too small, the amount of water in the electrolyte membrane 112 becomes too small and the mobility of hydrogen ions becomes small. On the other hand, when the humidification amount Wh is excessive, the electrolyte membrane 1
The amount of water in 12 becomes excessive, and the cathode side passage 114c
This is because the water is accumulated in p, so that sufficient oxygen gas cannot be supplied to the cathode 114c. In the following, a state in which the amount of water in the electrolyte membrane 112 is too small is also called a “dry state”, and a state in which the amount of water in the electrolyte membrane 112 is too large is also called a “flooding state”.

As described above, it is desirable that the oxidizing gas be appropriately humidified. Therefore, in the present embodiment, the humidification amount of the oxidizing gas is adjusted by adjusting the number of rotations of the rotating member 330 in the adsorption / dehumidification unit 320.

FIG. 7 is a graph showing the relationship between the rotation speed of the rotating member 330 and the humidifying amount Wh of the oxidizing gas. The three curves C1 to C3 show the relationships when the load of the fuel cell 100 is different.

When the load of the fuel cell changes, in order to change the output current of the fuel cell, the reaction gas (fuel gas and oxidizing gas) having a flow rate according to the load is supplied to the fuel cell. Specifically, the greater the load on the fuel cell,
The reaction gas flow rate is set large. The flow rate means the volume of the fluid (reaction gas) flowing per unit time. In the present embodiment, the adjustment of the fuel gas flow rate can be realized, for example, by controlling the amount of the mixed liquid introduced into the first evaporator 222 of FIG. The adjustment of the oxidizing gas flow rate can be realized by controlling the blower 310, for example.

The first curve C1 shows the case where the load of the fuel cell is relatively large (that is, the flow rate of the oxidizing gas is relatively large), and the third curve C3 shows the case where the load of the fuel cell is relatively large. The case is small (that is, the flow rate of the oxidizing gas is relatively small).

As can be seen from the three curves C1 to C3,
Humidification amount of oxidizing gas (that is, the amount of water contained in the oxidizing gas discharged from the adsorption / dehumidification unit 320 per unit time) Wh
(Mol / min) increases as the oxidizing gas flow rate increases. The humidifying amount Wh (mol / min) of the oxidizing gas increases as the rotation speed (rpm) of the rotating member 330 increases. In the present embodiment, the humidification amount of the oxidizing gas is adjusted by adjusting the number of rotations of the rotating member 330 in the adsorption / desorption unit 320 based on the relationship shown in FIG. 7.

FIG. 8 shows the rotating member 33 in the first embodiment.
It is explanatory drawing which shows the electric constitution for adjusting the rotation speed of 0. As shown in the drawing, the motor 4
02 is connected, and the motor 402 is connected to the control unit 400A. The motor 402 rotates the rotating member 330, and the control unit 400A controls the motor 402 to adjust the number of rotations of the rotating member 330. Further, a hygrometer 410 is provided in the oxidizing gas passage 352 (FIG. 4) on the downstream side of the adsorption / dehumidification unit 320. The hygrometer 410 measures the absolute humidity of the oxidizing gas discharged from the adsorption / dehumidification unit 320, and gives the measurement result to the control unit 400A.

The control unit 400A, the motor 402 and the hygrometer 410 shown in FIG. 8 correspond to the control section in the present invention.

When the absolute humidity of the oxidizing gas is relatively high, the amount of water in the electrolyte membrane 112 is relatively large, and when the absolute humidity of the oxidizing gas is relatively low, the electrolyte membrane 11 is large.
The amount of water in 2 is relatively small. That is, when the absolute humidity of the oxidizing gas is kept within a predetermined range, the water content in the electrolyte membrane 112 is kept within an appropriate range.

The control unit 400A of this embodiment controls the absolute humidity to be substantially equal to the preset target value.
The rotation speed of the rotating member 330 is adjusted. By doing so, the amount of water in the electrolyte membrane 112 can be easily kept within an appropriate range, and as a result, the output voltage of the fuel cell 100 can be kept substantially constant.

The amount of water deprived from the electrolyte membrane 112 of the fuel cell 100 changes according to the load of the fuel cell (in other words, according to the flow rate of oxidizing gas). The target value is set according to the load. That is, a target value of absolute humidity corresponding to the load of the fuel cell is stored in advance in a memory (not shown) in the control unit 400A.

As described above, in the present embodiment, the target value is set according to the load of the fuel cell, but the fuel cell system of the present embodiment is applied to an apparatus in which the load of the fuel cell hardly changes. In this case, the same target value may be used regardless of the load. However, when the fuel cell system is mounted on a moving body such as a vehicle, it is desirable to set the target value according to the load of the fuel cell as in the present embodiment.

Although the absolute humidity of the oxidizing gas is measured in this embodiment, the absolute humidity may be obtained by measuring pressure, temperature and relative humidity instead.
Further, although the absolute humidity is measured in the present embodiment, there is a possibility that the rotation speed of the rotating member 330 can be adjusted well even if the relative humidity is measured.

Generally, the control unit may adjust the rotation speed of the rotating member 330 so that the humidity of the oxidizing gas discharged from the adsorption / desorption unit 320 is maintained within a predetermined range.

By the way, when the number of rotations of the rotating member 330 is outside the predetermined range during the normal operation other than the start and stop of the fuel cell system, it is considered that some abnormality has occurred. Therefore, the control unit 400A of the present embodiment controls the blower 310 (FIG. 1) to adjust the flow rate of the oxidizing gas supplied to the fuel cell 100, so that the water content in the electrolyte membrane 112 falls within an appropriate range. Keep it at. The blower 310 corresponds to the flow rate adjusting unit in the present invention.

Specifically, when the rotation speed of the rotating member 330 is equal to or higher than the relatively large first limit value, it is considered that the adsorption / dehumidification unit 320 cannot properly humidify the oxidizing gas. In such a case, the electrolyte membrane 112 may be in a dry state, and therefore the control unit 400A determines that there is an abnormality and reduces the oxidizing gas flow rate. When the flow rate of the oxidizing gas decreases, the amount of water taken from the surface of the electrolyte membrane 112 decreases, so that the drying of the electrolyte membrane 112 can be reduced. As a result, it is possible to reduce the decrease in the output voltage of the fuel cell 100.

On the other hand, when the rotation speed of the rotating member 330 is equal to or lower than the relatively small second limit value, the adsorption / dehumidification unit 320
Is thought to have excessively humidified the oxidizing gas. This can occur, for example, due to deterioration of the moisture exchange section 334 (FIG. 5). In such a case, the electrolyte membrane 11
2 may be in a flooding state, the control unit 400A determines that there is an abnormality and increases the flow rate of the oxidizing gas. When the flow rate of the oxidizing gas is increased, the water condensed in the cathode side passage 114cp of the fuel cell 100 can be removed, so that the flooding of the electrolyte membrane 112 can be reduced. As a result, it is possible to reduce the decrease in the output voltage of the fuel cell 100.

The first and second limit values may be stored in a memory (not shown) in the control unit 400A.

As described above, in the fuel cell system of this embodiment, the moisture in the oxidizing off gas is absorbed in the middle of both the oxidizing gas passage 352 and the oxidizing off gas passage 354, and the moisture is absorbed in the oxidizing gas. Releasable rotating member 330
The adsorption / dehumidification unit 320 including is disposed. Rotating member 33
When the number of revolutions of 0 is increased, the amount of water in the oxidizing gas increases, and when the number of revolutions of the rotating member 330 is decreased, the amount of water in the oxidizing gas decreases. Therefore, the rotating member 33
By adjusting the number of rotations of 0, the amount of water in the oxidizing gas supplied to the fuel cell can be easily adjusted.

Further, since the amount of water in the electrolyte membrane 112 can be kept within an appropriate range by adjusting the number of rotations of the rotating member 330, the fuel cell system has a fluctuation in load when starting or stopping. It is possible to generate electric power stably even at times.

B. Second Embodiment: FIG. 9 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the second embodiment. In FIG. 9, the hygrometer 410 of FIG.
Instead of this, a voltmeter 420 is provided. Voltmeter 42
0 is connected to the fuel cell 100, measures the output voltage of the fuel cell, and gives the measurement result to the control unit 400B.

The control unit 400B, the motor 402 and the voltmeter 420 shown in FIG. 9 correspond to the control section in the present invention.

As described with reference to FIG. 6, if the amount of water in the electrolyte membrane 112 is not kept within an appropriate range, the output voltage of the fuel cell 100 will drop. In other words, when the output voltage of the fuel cell is kept within a predetermined range, the water content in the electrolyte membrane 112 is kept within an appropriate range.

The control unit 400B of the present embodiment adjusts the rotation speed of the rotating member 330 so that the output voltage given by the voltmeter 420 becomes a predetermined value or more. by the way,
The output voltage of the fuel cell 100 decreases in both the dry state and the flooding state. Therefore, when the output voltage becomes lower than the predetermined value, the control unit 400B temporarily increases or decreases the rotation speed of the rotating member 330 to determine whether it is the dry state or the flooding state. For example, when the output voltage becomes lower than the predetermined value, the control unit 400B slightly increases the rotation speed of the rotating member 330. As a result, if the output voltage becomes large, the control unit 400B determines that it is in a dry state,
The rotation speed of the rotating member 330 is further increased. On the other hand, when the output voltage becomes low, the control unit 400B determines that the flooding state is present and reduces the rotation speed of the rotating member 330.

FIG. 10 is an explanatory view showing a modification of the second embodiment (FIG. 9). Although FIG. 10 is almost the same as FIG. 9, the hygrometer 410 of FIG. 8 is added. The control unit 400Ba includes a voltmeter 420 and a hygrometer 410.
The rotation speed of the rotating member 330 is adjusted using the measurement result given by

The control unit 400Ba, the motor 402, and the two measuring instruments 410 and 420 shown in FIG. 10 correspond to the control section in the present invention.

Similar to the control unit 400B of FIG. 9, the control unit 400Ba adjusts the rotation speed of the rotating member 330 so that the output voltage given by the voltmeter 420 becomes a predetermined value or more. However, the control unit 400Ba
Refers to the absolute humidity given by the hygrometer 410 when the output voltage becomes smaller than a predetermined value. And
When the absolute humidity is relatively low, it is determined to be a dry state, and the rotation speed of the rotating member 330 is increased. On the other hand, when the absolute humidity is relatively high, it is determined that the flooding state has occurred, and the rotation speed of the rotating member 330 is reduced.

In this way, the control unit 400B
Since it is possible to determine the dry state or the flooding state without temporarily increasing or decreasing the rotational speed of the rotating member 330, it is possible to adjust the rotational speed of the rotating member 330 relatively quickly. .

As described above, the control unit of the present embodiment adjusts the rotation speed of the rotating member 330 so that the output voltage of the fuel cell 100 is kept within a predetermined range. It is possible to easily keep the amount of water in an appropriate range, and as a result, it is possible to keep the output voltage of the fuel cell 100 substantially constant.

In the first embodiment, since the rotation speed of the rotating member 330 is adjusted using the absolute humidity of the oxidizing gas, it is determined whether the water content in the electrolyte membrane 112 is kept within an appropriate range. It is actually unknown. Therefore, the output voltage of the fuel cell 100 may decrease. However, in the present embodiment, since the rotation speed of the rotating member 330 is adjusted using the output voltage of the fuel cell 100, it is possible to reliably suppress the decrease in the output voltage of the fuel cell 100, and also the electrolyte membrane. The amount of water in 112 can be kept within an appropriate range. Therefore, the configuration of the present embodiment is particularly effective when it is relatively difficult to control the amount of water in the electrolyte membrane when the fuel cell system is started, stopped, or when the load changes.

C. Third Embodiment: FIG. 11 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the third embodiment. As shown, in the present embodiment, the oxidation-off gas passage 354 on the downstream side of the fuel cell 100 is provided.
In FIG. 4, a pressure gauge 432 and a thermometer 434 are provided. The fuel cell 100 also includes an ammeter / voltmeter 43.
0 is connected. The pressure gauge 432 and the thermometer 434 respectively measure the pressure and temperature of the oxidizing off gas discharged from the fuel cell 100, and give the measurement result to the control unit 400C. Further, the ammeter / voltmeter 430 measures the output current and the output voltage of the fuel cell 100 and gives the measurement result to the control unit 400C.

The control unit 400C, the motor 402, and the three measuring instruments 430, 432, 434 shown in FIG. 11 correspond to the control section in the present invention.

By the way, the electrolyte membrane 11 of the fuel cell 100.
When the water depleted from No. 2 is replenished by the water contained in the oxidizing gas discharged from the adsorption / dehumidification unit 320,
The water content in the electrolyte membrane 112 is kept substantially constant. Therefore, when the following equation (7) is satisfied, the water content in the electrolyte membrane 112 is kept substantially constant.

[0087]     Wo-Wg = Wht (7)

Here, “Wo” is the oxidation off gas (that is,
The amount of water contained in the off gas supplied to the adsorption / dehumidification unit (mol)
/ Min). “Wg” is the amount of generated water (mol / min) generated in the fuel cell 100 per unit time. The water amount Wo includes the generated water amount Wg and the amount of water deprived from the electrolyte membrane 112 per unit time. Further, “Wht” is the amount of water (mol / min) that should be contained in the oxidizing gas discharged from the adsorption / dehumidification unit 320 per unit time, that is, the theoretical amount of humidification of the oxidizing gas.

As can be seen from the above description, when the difference between the two water amounts Wo and Wg is kept within a predetermined range, in other words, the difference between the two water amounts Wo and Wg is the theoretical humidification amount Wh.
When it is substantially equal to t, the water content in the electrolyte membrane 112 is kept within an appropriate range.

The control unit 400C of the present embodiment uses the measurement results provided from the respective measuring instruments 432, 434, 430 so that the equation (7) is satisfied, in other words, the humidifying amount Wh of the oxidizing gas Wh. The rotational speed of the rotating member 330 is adjusted so that is substantially equal to the theoretical humidification amount Wht.

The water amount Wo can be obtained from the pressure and temperature of the oxidizing off gas. That is, the fuel cell 1
Immediately after being discharged from 00, the oxidizing off gas is usually moist air (saturated moist air) having a relative humidity of 100%. Therefore, the saturated vapor pressure of the oxidizing off gas can be known from the pressure and the temperature of the oxidizing off gas. Further, since the oxidizing gas flow rate is determined according to the load of the fuel cell 100, the oxidizing off gas flow rate is known. Therefore, the state equation can be used to determine the water amount Wo. Further, the generated water amount Wg is determined from the current and voltage measured by the ammeter / voltmeter 430. And two water volumes Wo, W
By using g, the amount of water to be supplied to the fuel cell per unit time, that is, the theoretical humidification amount Wht can be obtained.

FIG. 12 is an explanatory view showing a modification of the third embodiment (FIG. 11). FIG. 12 is almost the same as FIG. 11, but a hygrometer 436 is added. Hygrometer 436
Is the oxidation off-gas passage 354 on the downstream side of the fuel cell 100.
(FIG. 4), the relative humidity of the oxidizing off gas discharged from the fuel cell 100 is measured, and the measurement result is given to the control unit 400Ca.

The control unit 400Ca, the motor 402 and the four measuring instruments 430, 432, 434 shown in FIG.
436 corresponds to the control unit in the present invention.

In FIG. 11, the oxidizing off gas has a relative humidity of 1
Although treated as 00% saturated humid air, in some cases, relative humidity may be less than 100%.
Therefore, in this embodiment, the theoretical humidification amount Wht is obtained more accurately by using the relative humidity of the oxidizing off gas. That is, since the saturated vapor pressure of the oxidizing off gas is known from the pressure and the temperature of the oxidizing off gas, the vapor pressure of the oxidizing off gas can be known by using the relative humidity. If this water vapor pressure is used, the water amount Wo can be obtained more accurately, and therefore the theoretical humidification amount Wht can be obtained more accurately.
With this configuration, the control unit 400Ca can accurately adjust the rotation speed of the rotating member 330.

As described above, the control unit of the present embodiment adjusts the rotation speed of the rotating member 330 so that the difference between the two water amounts Wo and Wg is kept within a predetermined range.
The amount of water in the electrolyte membrane 112 can be easily kept within an appropriate range, and as a result, the output voltage of the fuel cell 100 can be kept substantially constant.

D. Fourth Embodiment: FIG. 13 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the fourth embodiment. In FIG. 13, the current of FIG.
Instead of the voltmeter 430, a pressure gauge 442, a thermometer 444 and a hygrometer 446 are provided. Three measuring instruments 44
2, 444 and 446 are provided in the oxidation off-gas passage 354 (FIG. 4) on the downstream side of the adsorption / dehumidification section 320, and the pressure, temperature, and relative humidity of the oxidation off-gas discharged from the adsorption / dehumidification section 320, respectively. Is measured and the measurement result is given to the control unit 400D.

The control unit 400D, the motor 402, and the six measuring instruments 432, 434, 436, 4 of FIG.
42, 444 and 446 correspond to the control unit in the present invention.

By the way, in the adsorption / desorption unit 320, the following equation (8) is established.

[0099]     Wo-Wd = Whp (8)

Here, “Wo” is the same as the equation (7). “Wd” is the amount of water (mol / min) contained in the oxidation off gas discharged from the adsorption / dehumidification unit 320 per unit time. “Whp” is the adsorption / desorption unit 320 per unit time.
Amount of water (mol / mi contained in the oxidizing gas discharged from the
n), that is, the current humidification amount of the oxidizing gas.

As can be seen from the equation (8), the two water amounts W
The difference between o and Wd is substantially equal to the current humidification amount Whp of the oxidizing gas. Therefore, when the difference between the two water amounts Wo and Wd (that is, the current humidification amount Whp) is kept within a predetermined range, the water amount in the electrolyte membrane 112 is kept within an appropriate range.

The control unit 400D according to the present embodiment includes measuring devices 432, 434, 436, 442, 444 and 446.
The rotation speed of the rotating member 330 is adjusted so that the current humidification amount Whp is maintained within the appropriate range Wh1 to Wh2 shown in FIG.

The water amount Wo can be obtained by using the pressure, temperature and relative humidity of the oxidizing off gas discharged from the fuel cell 100, as described above. Similarly, the amount of water W
d can also be calculated using the pressure, temperature, and relative humidity of the oxidizing off gas discharged from the adsorption / dehumidification unit 320. Then, using the two water amounts Wo and Wd, the current humidification amount Wh
p can be obtained.

The control unit 400D uses the current humidification amount Wh
When p becomes smaller than the first limited humidification amount Wh1, the rotation member 33 is set so that the current humidification amount Whp becomes large.
Increase the 0 rpm. On the other hand, the control unit 400D
When the current humidification amount Whp is larger than the second limited humidification amount Wh2, the rotational speed of the rotating member 330 is reduced so that the current humidification amount Whp becomes smaller. The two limited humidification amounts Wh1 and Wh2 are determined by the control unit 400D.
It is stored in advance in a memory (not shown).

FIG. 14 is an explanatory view showing a modification of the fourth embodiment (FIG. 13). FIG. 14 is almost the same as FIG. 13, but instead of the three measuring devices 442, 444, 446,
A water meter 448 is provided. The water meter 448 is a condenser 390 (FIG. 1) arranged on the downstream side of the adsorption / desorption unit 320.
Is connected to the control unit 400, and measures the amount of water condensed by the condenser 390 per unit time.
Give to Da.

The control unit 400Da, the motor 402 and the four measuring instruments 432, 434, 436 shown in FIG.
Reference numeral 448 corresponds to the control unit in the present invention.

The amount of water condensed in the condenser 390, that is, the measurement result obtained by the water amount meter 448 is considered to be substantially equal to the amount Wd of water. Therefore, the control unit 40
0 Da is set so that the current humidification amount Whp of the formula (8) is kept within the appropriate range Wh1 to Wh2 shown in FIG. 6 even if the measurement results given from the respective measuring devices 432, 434, 436, 448 are used. The rotation speed of the rotating member 330 can be adjusted.

The measurement result of the water amount meter 448 is almost equal to the water amount Wd when the condensation temperature is sufficiently low, but becomes smaller than the water amount Wd when the condensation temperature is relatively high. In such a case, the water temperature Wd may be obtained more accurately by measuring the condensation temperature, the pressure, and the like. In this way, the control unit 400Da can adjust the rotation speed of the rotating member 330 with relatively high accuracy.

As described above, the control unit of the present embodiment adjusts the rotation speed of the rotating member 330 so that the difference between the two water amounts Wo and Wd is kept within a predetermined range.
The amount of water in the electrolyte membrane 112 can be easily kept within an appropriate range, and as a result, the output voltage of the fuel cell 100 can be kept substantially constant.

E. Fifth Embodiment: FIG. 15 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the fifth embodiment. 15, instead of the three measuring instruments 432, 434, 436 of FIG. 12, the same water meter 448 as that of FIG. 14 is provided. The control unit 400E of the present embodiment includes a current / voltmeter 430 and a water meter 448.
The rotation speed of the rotating member 330 is adjusted using the measurement result given by

The control unit 400E, the motor 402, and the two measuring instruments 430 and 448 shown in FIG. 15 correspond to the control section in the present invention.

As can be seen by comparing the above equations (7) and (8), the water amount Wd of the equation (8) is the generated water amount W of the equation (7).
When it is almost equal to g, the current humidification amount Whp in equation (8)
Is approximately equal to the theoretical humidification amount Wht in equation (7). At this time, as described above, the amount of water in the electrolyte membrane 112 is kept substantially constant. In other words, when the difference between the water amount Wd and the generated water amount Wg is kept within a predetermined range, the electrolyte membrane 1
The amount of water in 12 is kept within an appropriate range.

The control unit 400E of this embodiment uses the rotating member 3 so that the water amount Wd is equal to the generated water amount Wg.
Adjust the rotation speed of 30. Specifically, when the water amount Wd is larger than the generated water amount Wg, the current humidification amount Whp is relatively small, so the control unit 400E causes the rotating member 33 to rotate.
The number of rotations of 0 is increased to increase the current humidification amount Whp. On the other hand, when the water amount Wd is smaller than the generated water amount Wg, the current humidification amount Whp is relatively large, so the control unit 400E reduces the rotation speed of the rotating member 330 to reduce the current humidification amount Whp. Accordingly, the control unit 400E can adjust the rotation speed of the rotating member 330 so that the current humidification amount Whp is kept substantially constant within the appropriate range Wh1 to Wh2 shown in FIG.

As described above, the control unit of the present embodiment adjusts the rotation speed of the rotating member 330 so that the difference between the two water amounts Wd and Wg is kept within a predetermined range.
The amount of water in the electrolyte membrane 112 can be easily kept within an appropriate range, and as a result, the output voltage of the fuel cell 100 can be kept substantially constant.

Also, the control unit 400E of this embodiment.
Are control units 400C, 4 of the third and fourth embodiments.
Unlike 00Ca, 400D, and 400Da, it is not necessary to obtain the amount of water using the state quantity of gas, and therefore, there is an advantage that the rotation speed of the rotating member 330 can be adjusted relatively easily.

The present invention is not limited to the above embodiments and embodiments, but can be implemented in various modes without departing from the scope of the invention.
For example, the following modifications are possible.

(1) In the above embodiment, as shown in FIG. 1, the combustion section 240 for treating the carbon monoxide gas generated by the reforming reaction is provided on the downstream side of the reforming section 232. However, instead of this, a shift section and a CO oxidation section may be provided. The shift unit produces hydrogen gas and carbon dioxide gas from carbon monoxide gas and water vapor. The CO oxidation unit oxidizes the carbon monoxide gas that is not processed in the shift unit to generate carbon dioxide gas. When the shift unit is provided as described above, it is preferable that the hydrogen gas generated in the shift unit is merged with the fuel gas discharged from the extraction unit 236 and supplied to the fuel cell 100. This makes it possible to improve the utilization efficiency of hydrogen gas.

(2) In the above embodiment, the control unit is equipped with various measuring instruments, but other measuring instruments may be used. Generally, the control unit may include a measuring device used for measuring specific information relating to the amount of water contained in the electrolyte layer of the fuel cell.

(3) In the above embodiment, the adsorption / desorption unit 320
Is disposed in the middle of both the oxidizing gas passage 352 and the oxidizing off gas passage 354, but instead of this or together with this, the adsorption / dehumidification portion is provided in both the fuel gas passage and the fuel off gas passage. It may be arranged in the middle of the passage.

In general, the adsorbing / dehumidifying portion may be arranged in the middle of both the reaction gas passage through which the reaction gas supplied to the fuel cell passes and the off gas passage through which the off gas discharged from the fuel cell passes. .

(4) In the above embodiment, the adsorption / desorption unit 320
Includes a rotating member 330 in which the wall surface of each passage of the honeycomb member is coated with zeolite, but instead of this, a rotating member formed of a porous material such as alumina may be provided. .

In general, the adsorbing / dehumidifying portion may include a rotating member capable of absorbing the water in the off gas and releasing the water in the reaction gas.

(5) In the above embodiment, the fuel cell system is provided with the fuel gas supply section 200 for producing a fuel gas containing hydrogen gas using methanol, but instead of this, another alcohol or A fuel gas supply unit for generating a fuel gas containing hydrogen gas using natural gas, gasoline, ether, aldehyde or the like may be provided. In general, various hydrocarbon compounds containing hydrogen atoms can be used as the raw material.

Further, in the above-mentioned embodiment, the fuel cell system is provided with the fuel gas supply section 200 for producing hydrogen gas by reforming methanol, but instead of this, a hydrogen storage alloy, a hydrogen cylinder, etc. A fuel gas supply unit for obtaining hydrogen gas from may be provided.

(6) In the above embodiments, the case where the present invention is applied to a polymer electrolyte fuel cell has been described. However, the present invention is directed to other cases where the amount of water contained in the electrolyte layer of the fuel cell needs to be controlled. It is also applicable to fuel cells of the type.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration inside a fuel cell 100.

FIG. 3 is an explanatory diagram showing an appearance of a moisture absorption / dehumidification unit 320 (FIG. 1).

FIG. 4 is a schematic cross-sectional view of a moisture absorption / dehumidification unit 320 shown in FIG.

5 is an explanatory diagram showing an appearance of a rotating member 330 of FIG.

6 is a graph schematically showing the relationship between the humidification amount of oxidizing gas by the adsorption / desorption unit 320 and the output voltage of the fuel cell 100. FIG.

FIG. 7 is a graph showing the relationship between the number of rotations of a rotating member 330 and the humidification amount of oxidizing gas.

FIG. 8 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the first embodiment.

FIG. 9 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the second embodiment.

FIG. 10 is an explanatory diagram showing a modified example of the second embodiment (FIG. 9).

FIG. 11 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the third embodiment.

FIG. 12 is an explanatory diagram showing a modification of the third embodiment (FIG. 11).

FIG. 13 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the fourth embodiment.

FIG. 14 is an explanatory diagram showing a modification of the fourth embodiment (FIG. 13).

FIG. 15 is an explanatory diagram showing an electrical configuration for adjusting the rotation speed of the rotating member 330 in the fifth embodiment.

[Explanation of symbols]

100 ... Fuel cell 110 ... Single cell 112 ... Electrolyte membrane 114a ... Anode 114c ... Cathode 114ap ... Anode side passage 114cp ... Cathode side passage 116 ... Separator 200 ... Fuel gas supply section 212 ... Raw material tank 214 ... Water tank 222, 224 ... Evaporation Unit 230 ... Fuel gas generation unit 232 ... Reforming unit 234 ... Hydrogen separation membrane 236 ... Extraction unit 240 ... Combustion unit 250 ... Condenser 300 ... Oxidizing gas supply unit 310 ... Blower 320 ... Adsorption / dehumidification unit 330 ... Rotating member 332 ... Shaft member 334 ... Moisture exchange part 340 ... Storage parts 341, 342 ... Partition plates 345, 346 ... Seal member 352 ... Oxidizing gas passage 354 ... Oxidizing off gas passage 390 ... Condenser 400A, B, Ba, C, Ca, D, Da , E ... Control unit 402 ... Motor 410 ... Hygrometer 420 ... Voltmeter 430 ... Current / voltmeter 4 2 ... pressure gauge 434 ... thermometer 436 ... hygrometer 442 ... pressure gauge 444 ... thermometer 446 ... hygrometer 448 ... water meter

Claims (8)

[Claims] 1. A fuel cell system comprising: a fuel cell; a reaction gas passage through which a reaction gas supplied to the fuel cell passes; an off gas passage through which an off gas discharged from the fuel cell passes; and a reaction gas passage. And a dehumidifying / dehumidifying portion disposed in the middle of both the offgas passage and the offgas passage, the absorbing / dehumidifying portion including a rotating member capable of absorbing the moisture in the offgas and releasing the moisture into the reaction gas. And a control unit for rotating the rotating member and adjusting the number of rotations of the rotating member. 2. The fuel cell system according to claim 1, wherein the control unit includes a measuring device used for measuring specific information related to the amount of water contained in the electrolyte layer of the fuel cell, The unit adjusts the rotation speed of the rotating member using the information, and the fuel cell system. 3. The fuel cell system according to claim 2, wherein the control unit includes a flow rate adjusting unit for adjusting the flow rate of the reaction gas, and the control unit controls the rotation speed of the rotating member. A fuel cell system for adjusting the flow rate of the reaction gas when the value is outside a predetermined range. 4. The fuel cell system according to claim 2, wherein the information includes a humidity of the reaction gas discharged from the adsorption / dehumidification unit, and the control unit determines a humidity of the reaction gas to be a predetermined value. A fuel cell system in which the number of rotations of the rotating member is adjusted so as to be maintained within the range. 5. The fuel cell system according to claim 2, wherein the information includes an output voltage of the fuel cell, and the control unit keeps the output voltage of the fuel cell within a predetermined range. To adjust the number of rotations of the rotating member,
Fuel cell system. 6. The fuel cell system according to claim 2, wherein the information includes a first amount of water contained in the off gas discharged from the fuel cell and a second amount of water generated in the fuel cell. The fuel cell system, wherein the control unit adjusts the rotation speed of the rotating member such that the difference between the first water amount and the second water amount is maintained within a predetermined range. 7. The fuel cell system according to claim 2, wherein the information includes a first amount of water contained in the off gas discharged from the fuel cell and the off gas discharged from the adsorption / dehumidification unit. And a second water amount included in, wherein the control unit controls the rotation speed of the rotating member so that the difference between the first water amount and the second water amount is kept within a predetermined range. Adjust the fuel cell system. 8. The fuel cell system according to claim 2, wherein the information is a second amount contained in the first amount of water generated in the fuel cell and the off-gas discharged from the adsorbing / dehumidifying portion. The fuel cell, wherein the controller adjusts the rotation speed of the rotating member so that the difference between the first water quantity and the second water quantity is kept within a predetermined range. system.