JPH08273684A - Fuel cell system - Google Patents

Abstract

PURPOSE: To completely remove methanol in fuel gas from a fuel cell when operation of the fuel cell is stopped. CONSTITUTION: A flow regulating valve 34 and a bypass circuit 29 which heats purge gas by heat of a reformer 16 and bypasses this flow regulating valve 34, are arranged in a purge gas supply passage 28 to a fuel cell stack 10 from a purge gas tank 20 provided in a fuel cell system 1. When the fuel cell stack 10 is stopped, the purge gas regulated to a boiling point or more of methanol is supplied to the fuel cell stack 10 by the flow regulating valve 34 instead of fuel gas. As a result, since the fuel cell stack 10 is not cooled by supply of the purge gas, methanol in fuel gas in the fuel cell stack 10 is not liquefied, and is expelled still as gas from the fuel cell stack 10.

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 reformer for producing a fuel gas containing hydrogen from methanol and water, and an oxidizer containing the produced fuel gas and oxygen. The present invention relates to a fuel cell system including a fuel cell that uses gas and fuel as a fuel to generate electricity by an electrochemical reaction.

[0002]

2. Description of the Related Art Generally, a fuel cell is known as a device for directly converting the energy of fuel into electrical energy. In a fuel cell, usually, a pair of electrodes are arranged with an electrolyte in between, and one electrode (anode) is supplied with a fuel gas containing hydrogen and the other electrode (cathode) is supplied with an oxidizing gas containing oxygen. Then, the electric energy is taken out from between the electrodes by utilizing the electrochemical reactions represented by the following formulas (1) and (2) that occur on the surfaces of the pair of electrodes on the electrolyte side.

Anode reaction: H ₂ → 2H ⁺ + 2e ⁻ (1) Cathode reaction: 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O (2)

As a device for producing the fuel gas supplied to the fuel cell, there is a reformer for steam reforming methanol to produce a fuel gas containing a large amount of hydrogen. As a reformer of this type, generally, a methanol decomposition reaction represented by the following formula (3) and a carbon monoxide modification reaction represented by the following formula (4) are simultaneously advanced by supplying methanol and water. (Reaction of the following formula (5) as a whole), a reforming section for producing a reformed gas containing hydrogen and carbon dioxide, and the reformed gas produced in the reforming section are supplied. The unreacted carbon monoxide and water are similarly modified into hydrogen and carbon dioxide by a modification reaction of the following formula (4) to generate a fuel gas having a high hydrogen content.

CH ₃ OH → CO + 2H ₂ −21.7 kcal / mol (3) CO + H ₂ O → CO ₂ + H ₂ +9.8 kcal / mol (4) CH ₃ OH + H ₂ O → CO ₂ + 3H ₂ −11.9 kcal / Mol… (5)

[0006]

However, since it is practically difficult to completely carry out the reactions of the formulas (3) and (4), the fuel gas contains unreacted carbon monoxide and methanol. Therefore, there is a problem that the performance of the fuel cell is deteriorated. Carbon monoxide in the fuel gas is adsorbed on the platinum catalyst supported on the electrode to reduce the function as a catalyst, and inhibits the hydrogen decomposition reaction represented by the formula (1). The degree of this inhibition increases as the concentration of carbon monoxide in the fuel gas increases. Further, when the fuel cell is a polymer electrolyte fuel cell, methanol in the fuel gas reaches the cathode through the electrolyte membrane from the anode side, reacts with oxygen on the cathode side, and lowers the cathode potential, Although not so much as carbon monoxide, it adsorbs on a platinum catalyst to reduce its catalytic function and inhibits hydrogen decomposition reaction. The extent to which the cathode potential is lowered and the extent to which the hydrogen decomposition reaction is inhibited become greater as the concentration of methanol in the fuel gas increases.

In the polymer electrolyte fuel cell,
The electrolyte membrane and the electrode are joined by, for example, a hot pressing method, but methanol has a function of separating this joining, and particularly liquid methanol has a great influence. Therefore, when methanol is contained in the fuel gas, this bonded body is deteriorated. Further, when the fuel cell is stopped, methanol is liquefied together with the water vapor in the fuel gas as the temperature of the fuel cell is lowered. Therefore, depending on the concentration of methanol and the time the fuel cell is stopped, the electrolyte may It is conceivable that the membrane-electrode assembly will be immersed in liquid methanol for a long period of time, and the assembly will separate and no longer function as a fuel cell.

From the viewpoint of resource saving, the fuel cell system includes water contained in exhaust gas discharged from the fuel cell, for example, water obtained by humidifying a fuel gas or an oxidizing gas, or a reaction of the above equation (2) of the fuel cell. Some are equipped with a water recovery device for recovering the water generated by the exhaust gas from the exhaust gas (see, for example, Japanese Patent Laid-Open No. Hei 6)
-29036, JP-A-6-45000, JP-A-6-140065, etc.). In a fuel cell system equipped with such a water recovery device, most of the methanol contained in the fuel gas will be contained in the exhaust gas as it is. Therefore, when water is recovered from the exhaust gas, methanol is also recovered at the same time. Methanol will be mixed in the water system. When methanol is mixed in the water system of the fuel cell system as described above, this methanol is vaporized together with water when the fuel gas and the oxidizing gas are humidified, and mixed in these gases. It will also be mixed in water. Methanol corrodes many types of metal pipes and reduces or dissolves the strength of many types of plastic pipes.Therefore, in systems where methanol is not mixed, the water system pipes will corrode. In a system where methanol is mixed, the pipes for the water system, fuel gas, and oxidizing gas must all be made of a material having methanol resistance. .

Regarding the problems relating to carbon monoxide contained in fuel gas among these problems, the applicant has proposed a carbon monoxide detection device for detecting carbon monoxide in fuel gas with high accuracy, and at the same time, has proposed this carbon monoxide. A fuel cell system (Japanese Patent Application No. 6-293808) for controlling the operation of a reformer so as to reduce the concentration of carbon monoxide in fuel gas based on the concentration of carbon monoxide detected by a detector, and this modification. A fuel cell system (Japanese Patent Application No. 6-302834), which controls the operation of the fuel cell so as to prevent the output from the fuel cell from decreasing in addition to the control of the operation of the quality control device, has been proposed. Regarding the problem of methanol contained in the fuel gas, the applicant has proposed a methanol device that detects methanol in the fuel gas with high accuracy, and based on the concentration of methanol detected by the methanol detection device, A fuel cell system that controls the operation of the reformer so as to reduce the concentration of methanol in it, and in addition to controlling the operation of this reformer, also controls the operation of the fuel cell so as to prevent the output from the fuel cell from decreasing. We are proposing a fuel cell system, etc. (filed on the same day as this application).

However, in these proposed fuel cell systems, the allowable values are set so that the output of the fuel cell does not decrease with respect to the concentrations of carbon monoxide and methanol contained in the fuel gas, and carbon monoxide and methanol are used. Since the concentration is controlled to be less than or equal to each allowable value, methanol cannot be completely removed from the fuel gas. Therefore, in these systems, due to the problem that methanol in the fuel gas when the operation of the fuel cell is stopped is liquefied and adversely affects the assembly of the electrolyte membrane and the electrode, and the mixture of methanol in the water system of the system. The problem is not resolved.

The fuel cell system of the present invention aims to solve these problems, eliminate methanol in the fuel gas when the fuel cell is stopped, and prevent the mixture of methanol in the water system of the system. , Adopted the following configuration.

[0012]

According to a first aspect of the present invention, there is provided a fuel cell system in which a fuel gas containing hydrogen produced from methanol and water and an oxidizing gas containing oxygen are used as fuels. A fuel cell system including a fuel cell that generates power by reaction, wherein when the operation of the fuel cell is stopped, fuel gas supply stopping means for stopping the supply of fuel gas to the fuel cell, and the supply of the fuel gas The non-reactive gas that does not react with the fuel gas and the oxidizing gas in place of the fuel gas and supplies the fuel cell with the non-reactive gas; and the non-reactive gas supply means. The gist is that the heating means is provided for heating the non-reactive gas supplied to the fuel cell to at least the boiling point of methanol.

A fuel cell system according to a second aspect of the present invention is a fuel cell for generating electricity by an electrochemical reaction using a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen as fuels. A fuel cell system comprising: a fuel gas supply stopping means for stopping the supply of the fuel gas to the fuel cell when stopping the operation of the fuel cell; and with the stop of the supply of the fuel gas, A non-reactive gas supply means for supplying a predetermined amount of non-reactive gas that does not react with the fuel gas and the oxidizing gas to the fuel cell, and the non-reactive gas is supplied by the non-reactive gas supply means. The gist is that the fuel cell is provided with an oxidizing gas supply means for supplying the oxidizing gas instead of the non-reactive gas after the predetermined amount is supplied to the fuel cell.

A fuel cell system according to a third aspect of the present invention is a fuel cell system in which a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen are used as fuels to generate electricity by an electrochemical reaction. A fuel cell system comprising: a fuel gas supply stopping means for stopping the supply of the fuel gas to the fuel cell when stopping the operation of the fuel cell; and with the stop of the supply of the fuel gas, The gist of the present invention is to provide a pressure reducing means for gradually reducing the pressures of the fuel gas and the oxidizing gas in the fuel cell.

A fuel cell system according to a fourth aspect of the present invention is a fuel cell system in which a fuel gas containing hydrogen produced from methanol and water and an oxidizing gas containing oxygen are used as fuels to generate electricity by an electrochemical reaction. A fuel cell system comprising: a heating means for heating the fuel cell to at least the boiling point of methanol when starting the fuel cell; and, after heating the fuel cell by the heating means, to the fuel cell. And a fuel gas supply starting means for starting the supply of the fuel gas.

A fuel cell system according to a fifth aspect of the present invention is a fuel cell system that uses a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen as fuels to generate electricity by an electrochemical reaction. A water recovery means for recovering water from exhaust gas discharged from the fuel cell, wherein the water recovery means is a first predetermined temperature lower than an operating temperature of the fuel cell and higher than a boiling point of methanol. The first water recovery means set to the temperature of the
It is characterized in that it comprises a second water recovery means installed at a stage subsequent to the water recovery means and set to a second predetermined temperature lower than the boiling point of methanol.

According to a sixth aspect of the present invention, there is provided a fuel cell system including a reformer for producing a fuel gas containing hydrogen from methanol and water, and an oxidizing gas containing the produced fuel gas and oxygen. A fuel cell system including a fuel cell that generates electricity by an electrochemical reaction as a fuel, comprising an oxidizer that oxidizes methanol contained in exhaust gas on the oxidizing gas side of exhaust gas discharged from the fuel cell. The main point is that.

Here, in the fuel cell system according to claim 6, exhaust gas temperature detecting means for detecting the temperature of the exhaust gas on the oxidizing gas side, oxidation temperature detecting means for detecting the temperature of the oxidizing means, and Control means for controlling the operation of the reformer so as to reduce the concentration of methanol in the fuel gas based on the temperature detected by the exhaust gas temperature detection means and the temperature detected by the oxidation temperature detection means. It is also possible to adopt a configuration provided with (Claim 7).

In the fuel cell system according to the seventh aspect, the control means sets the deviation between the temperature detected by the exhaust gas temperature detection means and the temperature detected by the oxidation temperature detection means to a predetermined value or more. When the temperature becomes low, the operating temperature of the reformer may be controlled to a predetermined temperature higher than the ideal operating temperature (Claim 8).

A fuel cell system according to a ninth aspect of the present invention is a fuel cell system that uses a fuel gas containing hydrogen and oxygen-containing oxidizing gas produced from methanol and water as a fuel to generate electricity by an electrochemical reaction. A fuel cell system provided with a water recovery means for recovering water from the exhaust gas discharged from the fuel cell, the water recovery means being provided at a stage subsequent to the water recovery means and being included in the water recovered by the water recovery means. The gist is that an oxidizing means for oxidizing methanol is provided.

[0021]

In the fuel cell system according to claim 1 of the present invention configured as described above, when the fuel gas supply stopping means stops the operation of the fuel cell, the fuel gas containing hydrogen to the fuel cell. And the non-reactive gas supply means replaces the non-reactive gas that does not react with the fuel gas and the oxidizing gas containing oxygen with the fuel gas in the fuel cell. Supply. The heating means heats the non-reactive gas supplied to the fuel cell by the non-reactive gas supply means to at least the boiling point of methanol. As a result, the non-reactive gas having a temperature higher than the boiling point of methanol is supplied to the fuel cell.

In the fuel cell system according to the second aspect, when the fuel gas supply stopping means stops the operation of the fuel cell, the supply of the fuel gas containing hydrogen to the fuel cell is stopped, and the non-reactive gas is supplied. When the supply of the fuel gas is stopped, the supply means replaces the fuel gas with a non-reactive gas that does not react with the oxidizing gas containing the fuel gas and oxygen, and supplies a predetermined amount to the fuel cell. The oxidant gas supply means supplies the oxidant gas to the fuel cell in place of the non-reactive gas after the non-reactive gas supply means supplies a predetermined amount of the non-reactive gas to the fuel cell.

In the fuel cell system according to the third aspect, when the fuel gas supply stopping means stops the operation of the fuel cell, the supply of the fuel gas containing hydrogen to the fuel cell is stopped, and the depressurizing means, With the stop of this fuel gas supply,
The pressure of the fuel gas of the fuel cell and the oxidizing gas containing oxygen are gradually reduced.

In the fuel cell system according to the fourth aspect, the heating means heats the fuel cell to at least the boiling point of methanol when starting the fuel cell, and the fuel gas supply starting means heats the fuel cell by the heating means. Then, the supply of the fuel gas containing hydrogen to the fuel cell is started.

The fuel cell system according to claim 5 has a first temperature lower than the operating temperature of the fuel cell and higher than the boiling point of methanol.
The first water recovery means set to a predetermined temperature of
A second water recovery means, which recovers water from the exhaust gas discharged from the fuel cell at a predetermined temperature, is installed at a stage subsequent to the first water recovery means and is set to a second predetermined temperature lower than the boiling point of methanol. , Water is recovered from the exhaust gas discharged from the fuel cell at the second predetermined temperature.

In the fuel cell system according to claim 6, the reformer produces a fuel gas containing hydrogen from methanol and water, and the fuel cell produces an oxidizing gas containing the produced fuel gas and oxygen. Power is generated by an electrochemical reaction using and as fuel. The oxidizing means oxidizes methanol contained in the exhaust gas on the side of the oxidizing gas containing oxygen among the exhaust gases discharged from the fuel cell. As a result, methanol is removed from the exhaust gas on the oxidizing gas side.

In the fuel cell system according to the seventh aspect, the exhaust gas temperature detecting means detects the temperature of the exhaust gas on the oxidizing gas side, and the oxidizing temperature detecting means detects the temperature of the oxidizing means. The control means controls the operation of the reformer so as to reduce the concentration of methanol in the fuel gas based on the temperature detected by the exhaust gas temperature detection means and the temperature detected by the oxidation temperature detection means. ..

In the fuel cell system according to claim 8, the control means, when the deviation between the temperature detected by the exhaust gas temperature detecting means and the temperature detected by the oxidation temperature detecting means becomes a predetermined value or more, The operating temperature of the reformer is controlled to a predetermined temperature higher than the ideal operating temperature.

In a fuel cell system according to a ninth aspect, the fuel cell generates electricity by an electrochemical reaction using a fuel gas containing hydrogen and oxygen-containing oxidizing gas produced from methanol and water as a fuel to generate water. The recovery means recovers water from the exhaust gas discharged from the fuel cell. The oxidizing means provided after the water collecting means oxidizes the methanol contained in the water collected by the water collecting means.

[0030]

Preferred embodiments of the present invention will be described below in order to further clarify the structure and operation of the present invention described above. FIG. 1 is a block diagram illustrating a schematic configuration of a fuel cell system 1 which is a preferred embodiment of the present invention. As shown in the figure, the fuel cell system 1 includes a solid polymer fuel cell stack 10 that receives fuel to generate electric power, methanol stored in a methanol tank 12 and water stored in a water tank 14. A reformer 16 that produces a hydrogen-rich gas (fuel gas), a purge gas tank 20 that stores a gas (purge gas) that is inactive to hydrogen and oxygen in the normal operating state of the fuel cell stack 10, and the operation of each device. Control unit 50 for controlling
With.

The fuel cell stack 10 is a polymer electrolyte fuel cell as described above, and has the structure shown in FIG. 2 as its single cell structure. That is, as shown in FIG.
The cell is composed of an electrolyte membrane 61, an anode 62 and a cathode 63 as gas diffusion electrodes which sandwich the electrolyte membrane 61 from both sides to form a sandwich structure, and an anode 62 and a cathode 63 which sandwich the sandwich structure from both sides. Separators 64 and 65 that form a flow path of an oxidizing gas containing gas and oxygen;
An anode 62 and a cathode 63 arranged outside 65
And collector plates 66 and 67 serving as collector electrodes.

The electrolyte membrane 61 is a proton conductive membrane formed of a solid polymer material, for example, a fluorine resin, and exhibits good electric conductivity in a wet state. Anode 6
2 and the cathode 63 are both formed of a carbon cloth woven from threads made of carbon fibers, and carbon powder carrying platinum or an alloy of platinum and another metal as a catalyst is crossed on the carbon cloth. Is kneaded into the surface and the gap on the electrolyte membrane 61 side. In the embodiment, the anode 62 and the cathode 63 are formed of carbon cloth, but a configuration in which they are formed of carbon paper or carbon felt made of carbon fiber is also suitable.

The electrolyte membrane 61, the anode 62, and the cathode 63 are joined by the following method, for example, with the electrolyte membrane 61 sandwiched between the anode 62 and the cathode 63.

On the surface of an electrode base material (anode 62 and cathode 63, the same applies hereinafter) formed of carbon cloth or carbon paper or the like, catalyst powder prepared by previously supporting platinum on the surface of carbon powder is applied, Electrolyte membrane 6
Method of integrating 1 and this electrode base material by hot pressing.

On the surface of the electrode base material, a catalyst powder prepared by previously supporting platinum on the surface of carbon powder was applied, and the electrolyte membrane 61 and this electrode base material were adhered with a proton conductive solid polymer solution. How to integrate.

The catalyst powder prepared by previously supporting platinum on the surface of carbon powder is dispersed in an appropriate organic solvent to form a paste, which is applied to the surface of the electrolyte membrane 61 by a screen printing method or the like. After that, it is integrated with the electrode base material by hot pressing.

A method in which platinum is supported on the surface of the electrolyte membrane 61 by a thin film forming method such as a sputtering method, a vapor deposition method, a CVD method or a PVD method, and then integrated with an electrode base material by hot pressing.

The carbon powder supporting the platinum catalyst is prepared by the following method. First, an aqueous solution of chloroplatinic acid and sodium thiosulfate are mixed to obtain an aqueous solution of a platinum sulfite complex. While stirring this aqueous solution, hydrogen peroxide solution is removed to deposit colloidal platinum particles in the aqueous solution. Let
Next, while adding carbon black (for example, Vulcan XC-72 (trademark of CABOT Inc. in the US) or Denka Black (trademark of Denki Kagaku Kogyo Co., Ltd.)) as a carrier to this aqueous solution, the mixture is stirred to form a carbon black surface Deposit colloidal platinum particles. Then, the solution is suction-filtered or pressure-filtered to separate the carbon black to which the platinum particles are attached, then repeatedly washed with deionized water and completely dried at room temperature. Next, the agglomerated carbon black is crushed by a crusher, and the carbon black is crushed in a hydrogen reducing atmosphere at 250
The platinum on the carbon black is reduced by heating for about 2 hours at ℃ to 350 ℃, and the residual chlorine is completely removed to complete the platinum catalyst.

Density of platinum supported on carbon black (ratio of platinum weight on carbon to carbon weight)
Can be adjusted by changing the ratio between the amount of chloroplatinic acid and the amount of carbon black, and a platinum catalyst having any supported density can be obtained. The method for producing the platinum catalyst is not limited to the above-mentioned method, and may be produced by another method as long as sufficient catalytic activity can be obtained.

In the above description, in order to simplify the contents, the case where platinum is used has been described. In addition to this, platinum as the first component and ruthenium, nickel, cobalt, and vanadium as the second components are used. It is also possible to use an alloy catalyst composed of an alloy of one or more components selected from the group consisting of palladium, indium, iron, chromium, manganese and the like.

A method for producing a platinum-ruthenium catalyst (carbon powder carrying an alloy catalyst of platinum and ruthenium) as an example of the alloy catalyst will be described below. The platinum catalyst (carbon powder supporting the platinum catalyst) produced by the above-described method is dispersed in deionized water while stirring, and the ruthenium chloride aqueous solution is gradually added and stirred. Further, the sodium carbonate solution is gradually added and stirred to deposit ruthenium on the carbon black supporting the platinum catalyst. Next, the solution is suction-filtered or pressure-filtered to separate the carbon black on which ruthenium is deposited. The separated carbon black is repeatedly washed with deionized water,
Then, it is sufficiently dried at room temperature. The carbon black thus dried is pulverized by a pulverizer and heated in a hydrogen reducing atmosphere at 250 ° C. to 350 ° C. for about 2 hours to reduce platinum and ruthenium on the carbon black, and when ruthenium is deposited. Completely removes the chlorine that is taken up and remains. Then, by heating in an inert gas stream (nitrogen or argon) at 800 ° C. to 900 ° C. for about 1 hour, the platinum on the carbon black and ruthenium are alloyed to form a platinum-ruthenium catalyst (an alloy of platinum and ruthenium). A carbon powder carrying a catalyst is completed.

Here, the loading amounts of platinum and ruthenium can be adjusted from the loadings of carbon black and platinum loading ruthenium chloride. The method for producing the platinum-ruthenium catalyst is not limited to the above-mentioned method, and may be produced by any other method as long as sufficient catalytic activity can be obtained.

The separators 64 and 65 are formed of a gas impermeable conductive material, for example, dense carbon that is made gas impermeable by compressing carbon. As shown in the drawing, a plurality of ribs arranged in parallel are formed on the anode 62 side of the separator 64, and a flow passage groove 64p that forms a passage for fuel gas is formed between the rib and the surface of the anode 62. ing. Similarly, a plurality of ribs arranged in parallel are formed on the cathode 63 side of the separator 65, and the ribs and the surface of the cathode 63 form a flow channel groove 65p forming a passage for an oxidizing gas containing oxygen. Has been done.

The collector plates 66, 67 are made of a gas impermeable conductive material, for example, dense carbon that is made gas impermeable by compressing carbon.

The structure described above has the fuel cell stack 10
However, in reality, the separator 6
4, a plurality of anodes 62, electrolyte membranes 61, cathodes 63, and separators 65 are laminated in this order, and current collecting plates 66 and 67 are arranged on the outer sides thereof, whereby the fuel cell stack 1
0 is configured.

The anode side gas inlet 10a of the fuel cell stack 10 is connected to the reformer 16 by the fuel gas supply passage 22, and the fuel gas produced by the reformer 16 is passed through this fuel gas supply passage 22. Are supplied to the fuel cell stack 10. Also, the anode gas inlet 10a
Is connected to a fuel gas side supply manifold (not shown) included in the fuel cell stack 10, and is branched and connected to a plurality of flow channel grooves 64p on the fuel gas side of the fuel cell stack 10 via the supply manifold. The fuel gas supply passage 22 is provided with an electromagnetic valve 32 that controls the start and stop of the supply of the fuel gas manufactured by the reformer 16 to the fuel cell stack 10. The solenoid valve 32 is connected to the electronic control unit 50 by a conductive line and is controlled by the electronic control unit 50.

The anode side gas outlet 10b of the fuel cell stack 10 is connected to a fuel gas side discharge manifold (not shown) provided in the fuel cell stack 10, and a plurality of flow paths of the fuel cell stack 10 are passed through the discharge manifold. It is branched and connected to the groove 64p (connected from the side opposite to the fuel gas supply passage 22). The anode side gas outlet 10b is connected to the reformer 16 through the fuel gas discharge passage 24, and sends the fuel gas side discharge gas discharged from the fuel cell stack 10 to the reformer 16.

The cathode gas inlet 10c of the fuel cell stack 10 is connected to the blower 46 by the oxidizing gas supply passage 42, and the oxidizing gas (for example, air) is supplied to the fuel cell stack 10 by the blower 46. This cathode side gas inlet 10c is also connected to an oxidizing gas side supply manifold (not shown) included in the fuel cell stack 10 like the anode side gas inlet 10a, and the oxidizing gas side of the fuel cell stack 10 is connected via this supply manifold. Is branched and connected to a plurality of flow channel grooves 65p (a flow channel groove that faces the flow channel groove 64p connected to the anode gas inlet 10a with the electrolyte membrane 61 interposed therebetween). Note that the oxidizing gas supplied to the fuel cell stack 10 is the oxidizing gas supply passage 4
2 is humidified by a humidifier (not shown). Further, the blower 46 is connected to the electronic control unit 50 by a conductive line, and receives drive control by the electronic control unit 50.

Similarly to the anode side gas outlet 10b, the cathode side gas outlet 10d of the fuel cell stack 10 is also connected to an oxidant gas side discharge manifold (not shown) of the fuel cell stack 10, and the fuel is passed through this discharge manifold. It is branched and connected to a plurality of flow channel grooves 65p of the battery stack 10 (connected from the side opposite to the oxidizing gas supply passage 42). The cathode side gas outlet 10d is connected to a water recovery device (not shown) through the oxidizing gas discharge passage 44, and the oxidizing gas side exhaust gas discharged from the fuel cell stack 10 is included in the exhaust gas in the water recovery device. The collected water is released to the atmosphere after being collected.

The fuel cell stack 10 includes a pressure sensor 10 for detecting the pressure of the fuel gas in the fuel cell stack 10.
e and a temperature sensor 10f that detects the temperature in the fuel cell stack 10 are installed, and both sensors are connected to the electronic control unit 50 by a conductive line.

In the reformer 16, the decomposition reaction (the above equation (3)) in which methanol is decomposed into carbon monoxide and hydrogen, and the carbon monoxide generated by this decomposition reaction and water are reacted to generate carbon dioxide. And a reaction for generating hydrogen (the above formula (4)) are performed to produce a hydrogen-rich gas. Since these reactions are endothermic reactions (the above formula (5)) as a whole, the reformer 16 is equipped with a burner 16a for heating the reformer 16 in order to obtain the heat necessary for this reaction. A part of the fuel gas generated by the reformer 16 is supplied to the burner 16a as fuel, and the exhaust gas of the fuel gas system of the fuel cell stack 10 is sent through the fuel gas exhaust passage 24. Therefore, the unreacted hydrogen in the exhaust gas of the fuel gas system is burned by the burner 16a. The burner 16a is connected to the electronic control unit 50 by a conductive line, and the electronic control unit 50 burns the burner 16a, that is, the burner 16a.
The amount of fuel gas supplied to the reformer 16 is adjusted, and the operating temperature of the reformer 16 is controlled. The exhaust gas from the burner 16a is released to the atmosphere via the exhaust gas passage 26.

In the embodiment, the burner 16a is supplied with the exhaust gas of the fuel gas system of the fuel cell stack 10 and a part of the fuel gas generated by the reformer 16 as the fuel. A configuration is also suitable in which the methanol stored in the methanol tank 12 is supplied as a fuel by a pump instead of the fuel gas generated by. As described above, when methanol is used as the fuel of the burner 16a, it is possible to improve the energy efficiency and contribute to energy saving as compared with the case where the fuel gas that is a hydrogen-rich gas is reformed with methanol and the fuel gas is used as the fuel. You can

The purge gas tank 20 is a pressure tank for storing a purge gas (for example, an inert gas such as nitrogen gas or argon) which is inactive to hydrogen and oxygen in the normal operating state of the fuel cell stack 10 in this system. The purge gas supply passage 28 allows the fuel gas supply passage 2
It is connected to the downstream side of the second solenoid valve 32. The purge gas supply passage 28 is provided with a flow rate adjusting valve 34 for adjusting the flow rate of the purge gas and an electromagnetic valve 38 for controlling the start and stop of the supply of the purge gas. In addition, the purge gas supply passage 28 is provided with a bypass 29, a part of which is built in the reformer 16 and bypasses the flow rate control valve 34, and the purge gas passing through this bypass 29 is heated by the reformer 16. It is configured to do. Therefore, the flow rate of the purge gas passing through the flow rate adjusting valve 34 and the flow rate of the purge gas passing through the bypass 29 can be adjusted by adjusting the opening degree of the flow rate adjusting valve 34, so that the mixed gas is passed through each passage. The temperature of the purge gas can be adjusted to the desired temperature.
As described above, in order to adjust the temperature of the purge gas to a desired temperature by the opening degree of the flow rate control valve 34, the purge gas temperature sensor 36 for detecting the temperature of the purge gas mixed downstream of the confluence point of the bypass 29 of the purge gas supply passage 28. Is provided. The flow rate control valve 34 and the solenoid valve 38 are connected to the electronic control unit 50 by conductive lines, and are controlled by the electronic control unit 50. The purge gas temperature sensor 36 is also connected to the electronic control unit 50 by a conductive line.

The electronic control unit 50 is configured as a logic circuit centered on a microcomputer, and more specifically, a CPU 52 that executes a predetermined calculation and the like according to a preset control program, and the CPU 52 executes various calculation processes. A ROM 54 in which control programs and control data necessary for the above are stored in advance, a RAM 56 in which various data necessary for executing various arithmetic processes in the CPU 52 are temporarily read and written, and a fuel cell stack 10 The detection signals from the pressure sensor 10e, the temperature sensor 10f, and the purge gas temperature sensor 36 are input, and the drive signals are output to the burner 16a, the blower 46, the flow rate control valve 34, the solenoid valves 32, 38, etc. according to the calculation result of the CPU 52. The input / output port 58 and the like are provided. In addition, the electronic control unit 50 includes a timer 59 that counts time and a power supply circuit (not shown) that supplies necessary power to each unit.

Fuel cell system 1 constructed in this way
In the steady operation state, the solenoid valve 32 is open and the solenoid valve 38 is closed, and the electronic control unit 50 controls the methanol tank 12 and the water tank 14 so that the fuel cell stack 10 can generate electric power efficiently and stably. Control of supply flow rates of methanol and water to the reformer 16, control of supply amount of fuel gas to the burner 16a for heating the reformer 16, control of supply amount of oxidizing gas to the fuel cell stack 10, fuel cell The temperature of the stack 10 is controlled, and the electric power generated in the fuel cell stack 10 is supplied to a device (load) such as a motor connected to an output terminal (not shown) of the fuel cell stack 10 via a power supply line.

Next, the operation of stopping the operation of the fuel cell stack 10 in the fuel cell system 1 will be described based on the operation stop control routine of FIG. This routine is executed when the operator gives an instruction to stop the operation of the fuel cell system 1 to the electronic control unit 50, or when some abnormality is detected in the fuel cell system 1.

When this routine is executed, the CPU 52
First, a drive signal is output to the solenoid valve 32 via the input / output port 58 to close the solenoid valve 32 to stop the supply of fuel gas to the fuel cell stack 10 (step S10).
0). At the same time, the supply of methanol and water from the methanol tank 12 and the water tank 14 to the reformer 16 is also stopped. Next, the pressure P of the fuel gas in the fuel cell stack 10 and the temperature TF in the fuel cell stack 10 detected by the pressure sensor 10e and the temperature sensor 10f provided in the fuel cell stack 10 are passed through the input / output port 58. Read in (step S102). Then, the boiling point TM of methanol at the read pressure P is obtained (step S104). The boiling point TM of methanol can be obtained by examining the relationship between the boiling point of methanol and the pressure in advance and referring to the map stored in the ROM 54 as a map (not shown).

Next, the read fuel cell stack 10
The average of the internal temperature TF and the obtained boiling point TM of methanol is calculated as the target temperature TPM of the purge gas (step S
106). Here, the target temperature TPM is set as the target temperature of the purge gas when the purge gas is supplied to the fuel cell stack 10. This target temperature TP
When M is set, the purge gas temperature control routine (FIG. 4) described below is executed, whereby the fuel cell stack 1
The temperature of the purge gas supplied to zero is adjusted. In addition,
When the pressure P of the fuel gas in the fuel cell stack 10 is high,
The temperature TF in the fuel cell stack 10 may be lower than the boiling point TM of methanol. In this case, the target temperature T
PM is set to the temperature TF in the fuel cell stack 10.

Next, the CPU 52 outputs a drive signal to the solenoid valve 38 via the input / output port 58 to open the solenoid valve 38, so that both the fuel gas and the oxidizing gas are inactive and the target temperature TPM is reached. The purge gas whose temperature has been adjusted is supplied to the fuel cell stack 10 (step S108), and the process waits for a predetermined time after starting the supply of the purge gas (step S110). When the purge gas is supplied to the fuel cell stack 10, the purge gas mixes with the fuel gas remaining in the fuel cell stack 10 and expels the fuel gas from the fuel cell stack 10 as a whole. At this time, since the purge gas is adjusted to a temperature higher than the boiling point TM of methanol at the pressure P, even if it is mixed with the fuel gas, the temperature does not become lower than the boiling point TM of methanol. Therefore, even when unreacted methanol is contained in the fuel gas, the methanol is discharged from the fuel cell stack 10 together with the fuel gas as a gas without being liquefied in the fuel cell stack 10.
In addition, the time to supply the purge gas (the above-mentioned predetermined time)
Is set as the time required to almost completely discharge the fuel gas from the fuel cell stack 10 by the supply of the purge gas, and is determined by the structure, capacity, etc. of the fuel cell stack 10.

The temperature TF in the fuel cell stack 10
Is lower than the boiling point TM of methanol, the target temperature T
The temperature TF is set in PM, but in this state, the fuel gas contains only methanol up to the saturated vapor pressure of methanol at the temperature TF. Therefore, the same temperature T
When the adjusted purge gas is supplied to F, methanol is not liquefied and is discharged from the fuel cell stack 10 together with the fuel gas as it is.

When a predetermined time has passed in step S110,
The CPU 52 outputs a drive signal to the solenoid valve 38 to close the solenoid valve 38, stops the supply of the purge gas to the fuel cell stack 10 (step S112), and ends this routine.

In order to supply the purge gas adjusted to the target temperature TPM to the fuel cell stack 10 as described above, the electronic control unit 50 in step S108.
The purge gas temperature control routine illustrated in FIG. 4 is repeatedly executed every predetermined time (for example, every 10 msec) from when the supply of the purge gas to the fuel cell stack 10 is started in step S112 until the supply of the purge gas is stopped in step S112. To be done.

When this purge gas temperature control routine is executed, the CPU 52 first causes the purge gas temperature sensor 3 to operate.
The temperature TP1 of the purge gas detected by 6 is read via the input / output port 58 (step S120). Next, the deviation ΔT is calculated by subtracting the temperature TP1 of the purge gas read from the target temperature TPM of the purge gas (step S122), the calculated deviation ΔT is multiplied by the proportional gain K, and the flow rate acting to cancel the deviation is calculated. Control valve 34
Drive amount ΔS is calculated (step S124). And
The drive amount ΔS of the flow rate adjusting valve 34 is output to the flow rate adjusting valve 34 via the input / output port 58, and the flow rate adjusting valve 34 is driven by the drive amount ΔS (step S126). As a result,
The flow rate of the purge gas from the purge gas tank 20 through the flow rate control valve 34 and the flow rate of the purge gas through the bypass 29 are adjusted, and the temperature of the purge gas mixed through each passage is controlled to the target temperature TPM.

The fuel cell system 1 of the embodiment described above
According to the above, when the operation of the fuel cell stack 10 is stopped,
Since the purge gas adjusted to a temperature higher than the boiling point TM of methanol is supplied to the fuel cell stack 10 instead of the fuel gas, the methanol is liquefied in the fuel cell stack 10 even when the fuel gas contains unreacted methanol. Therefore, methanol can be discharged from the fuel cell stack 10 together with the fuel gas. As a result, methanol is liquefied in the fuel cell stack 10, and this liquefied methanol can be prevented from permeating the joined body of the electrolyte membrane 61, the anode 62, and the cathode 63 to separate the joined body. .

Further, the pressure P of the fuel gas in the fuel cell stack 10 is detected, the boiling point TM of methanol is determined based on the pressure P, and the boiling point TM of the methanol and the temperature TF in the fuel cell stack 10 are determined. Since the target temperature TPM of the purge gas is set by the above, the methanol in the fuel gas can be more reliably discharged from the fuel cell stack 10 even when the fuel cell stack 10 is stopped from the state where it is not in the steady operation state.

In the fuel cell system 1 of the embodiment,
The target temperature TPM of the purge gas was calculated as the average of the temperature TF in the fuel cell stack 10 and the boiling point TM of methanol at the pressure P of the fuel gas in the fuel cell stack 10.
Since it does not have to be liquefied inside, it may be any number of times as long as it is equal to or higher than the boiling point TM of methanol at this pressure P. Therefore, the target temperature TPM may be set to the boiling point TM of methanol, but it is difficult to set the temperature of the purge gas to the boiling point TM of methanol completely with normal control, and some error occurs, so the target temperature TPM is set to the target temperature TPM. The temperature TPM is preferably set to a temperature slightly higher than the boiling point TM of methanol. The target temperature TPM may be equal to or higher than the temperature TF of the fuel cell stack 10, but depending on the temperature of the purge gas, the cooling water in the fuel cell stack 10 may be boiled, and the amount of heat required for the purge gas may be increased. From the viewpoint of reducing the temperature, it is desirable that the temperature is equal to or lower than the temperature TF of the fuel cell stack 10.

Further, in the fuel cell system 1 of the embodiment,
The boiling point TM of the methanol is determined based on the pressure P of the fuel gas in the fuel cell stack 10, and the target temperature TPM is set based on the boiling point TM of the methanol and the temperature TF of the fuel cell stack 10. Assuming a possible pressure P of the fuel cell stack 10 in this state, the boiling point TM of methanol at the maximum value of the possible pressure P is preset as the target temperature TPM, and the pressure P and the temperature of the fuel gas in the fuel cell stack 10 It does not matter even if the TF is not detected.

Further, in the fuel cell system 1 of the embodiment, the supply of the purge gas to the fuel cell stack 10 is set to the predetermined time, but the fuel gas supply passage 22 is downstream of the confluence point of the purge gas supply passage 28 or the purge gas supply passage. 28 is provided with a flow meter, and the supply amount of the purge gas necessary for the fuel gas remaining in the fuel cell stack 10 to be almost completely discharged from the fuel cell stack 10 is obtained in advance by an experiment or the like, and this is set to a predetermined amount. Alternatively, the solenoid valve 38 may be closed when the supply amount obtained by integrating the flow rate detected by the flow meter reaches this predetermined amount.

Next, a fuel cell system 1B which is a second embodiment of the present invention will be described. FIG. 5 shows the second aspect of the present invention.
It is a block diagram which illustrates the outline of composition of fuel cell system 1B which is an example. As shown in the figure, the fuel cell system 1B according to the second embodiment includes a polymer electrolyte fuel cell stack 10 that receives fuel to generate electric power, a methanol tank 12, and a methanol and water tank 14. A reformer 16 for producing a hydrogen-rich gas (fuel gas) from the water, a purge gas tank 20 for storing a gas (purge gas) inert to hydrogen and oxygen in a normal operation state of the fuel cell stack 10, An electronic control unit 50 that controls the operation of each device. Fuel cell stack 1 included in the fuel cell system 1B of the second embodiment
0, the reformer 16, the purge gas tank 20, and the electronic control unit 50 have the same configuration as that of the fuel cell system 1 of the first embodiment except that the reformer 16 does not include a part of the bypass 29. Are doing Therefore, these devices are denoted by the same reference symbols as those assigned to the devices included in the fuel cell system 1 of the first embodiment, and the description thereof is omitted. Further, regarding the other devices included in the fuel cell system 1B of the second embodiment, the fuel cell system 1 of the first embodiment is also used.
Components having the same configurations as those of the devices are attached with the same reference numerals, and description thereof will be omitted.

The anode side gas inlet 10a of the fuel cell stack 10 is modified by the fuel gas supply passage 22 provided with a solenoid valve 32 in the middle, similar to the fuel cell stack 10 included in the fuel cell system 1 of the first embodiment. The gas outlet 10b on the anode side is connected to the reformer 16 through the fuel gas discharge passage 24. The cathode-side gas inlet 10c of the fuel cell stack 10 is also provided in the fuel cell system 1 of the first embodiment.
Like 0, it is connected to the blower 46 by the oxidizing gas supply passage 42. The exhaust gas on the oxidizing gas side of the fuel cell stack 10 is released to the outside air after water in the exhaust gas is recovered from a cathode side gas outlet 10d via an oxidizing gas exhaust passage 44 by a water recovery device (not shown). A solenoid valve 48 that controls the start and stop of the supply of the oxidizing gas to the fuel cell stack 10 is provided downstream of the blower 46 in the oxidizing gas supply passage 42.

The purge gas tank 20 is connected to the downstream side of the electromagnetic valve 32 of the fuel gas supply passage 22 by the purge gas supply passage 28.
An electromagnetic valve 38 that controls the start and stop of the supply of purge gas is provided. The downstream side of the solenoid valve 38 of the purge gas supply passage 28 is connected to the upstream side of the solenoid valve 48 on the downstream side of the blower 46 of the oxidizing gas supply passage 42 by the oxidizing gas communication passage 43. An electromagnetic valve 49, which is an opening / closing valve, is provided in the.

The electromagnetic valves 32, 38, 48, 49 provided in the fuel cell system 1B are connected to the electronic control unit 50 by conductive lines and are controlled by the electronic control unit 50.

In the fuel cell system 1B of the second embodiment thus constructed, the solenoid valve 32 and the solenoid valve 48 are open and the solenoid valve 38 and the solenoid valve 49 are closed in the steady operation state, and the fuel cell stack 10 So as to efficiently and stably generate power, similarly to the fuel cell system 1 of the first embodiment,
The electronic control unit 50 controls the supply flow rates of methanol and water from the methanol tank 12 and the water tank 14 to the reformer 16, and the burner 1 that heats the reformer 16.
Control of fuel gas supply to 6a, fuel cell stack 1
The supply amount of the oxidizing gas to the fuel cell stack 10 is controlled, and the electric power generated in the fuel cell stack 10 is supplied to a device (load) such as a motor connected to an output terminal (not shown) of the fuel cell stack 10 by a power supply line. To do.

In the electronic control unit 50 of the fuel cell system 1B of the second embodiment, when stopping the operation of the fuel cell stack 10, the operation stop control routine illustrated in FIG. 6 is executed. This routine is similar to the operation stop control routine in the fuel cell system 1 of the first embodiment, when the operator gives an instruction to stop the operation of the fuel cell system 1B to the electronic control unit 50 of the fuel cell system 1B. Alternatively, it is executed when any abnormality is detected in the fuel cell system 1.

When this routine is executed, the CPU 52
First, a drive signal is output to the solenoid valve 32 via the input / output port 58 to close the solenoid valve 32 to stop the supply of fuel gas to the fuel cell stack 10 (step S10).
0). At the same time, a drive signal is also output to the solenoid valve 48, and the solenoid valve 48 is closed to supply the oxidizing gas to the fuel cell stack 10 and to supply methanol to the reformer 16 from the methanol tank 12 and the water tank 14. Water supply is also stopped.

Next, the CPU 52 uses the input / output port 58.
A driving signal is output to the solenoid valve 38 via the solenoid valve 38 to open the solenoid valve 38 to start the supply of the purge gas to the fuel cell stack 10 (step S202), and a predetermined time T1 has elapsed since the supply of the purge gas was started. (Step S204), a drive signal is output to the solenoid valve 38, and the solenoid valve 3
8 is closed to stop the supply of purge gas (step S
206). Here, for a predetermined time T1, even if hydrogen, which is a mixed gas of the purge gas and the fuel gas in the fuel cell stack 10, supplies the oxidizing gas to the fuel cell stack 10, the oxygen in the oxidizing gas and the hydrogen in the mixed gas remain. Is set as a time longer than the time required to supply the required amount of purge gas so that the concentration is equal to or lower than the concentration at which no explosion occurs. This predetermined time T1 is determined by the structure and capacity of the fuel cell stack 10, the concentration of hydrogen in the fuel gas, and the like.

Subsequently, the CPU 52 uses the input / output port 58.
A drive signal is output to the solenoid valve 49 via the solenoid valve 49 to open the solenoid valve 49 to start the supply of the oxidizing gas to the fuel gas side of the fuel cell stack 10 (step S208), and to perform a predetermined time T.
Wait for 2 to elapse (step S210), and then the solenoid valve 4
A drive signal is output to 9, and the electromagnetic valve 49 is closed to stop the supply of oxidizing gas (step S212). Here, for a predetermined time T2, the fuel cell stack 1 is supplied with the oxidizing gas.
0 is longer than the time required to sufficiently discharge the purge gas and the remaining fuel gas from the fuel cell stack 10, and the fuel gas containing the maximum concentration of methanol allowed by the fuel cell stack 10 is When supplied to the fuel cell stack 10, sufficient oxidizing gas to vaporize all the methanol condensed on the inner wall of the fuel cell stack 10 when the fuel cell stack 10 is stopped and to exhaust from the fuel cell stack 10 is generated. It is set as the time required for supply, and is determined by the structure, capacity, etc. of the fuel cell stack 10.

According to the fuel cell system 1B of the second embodiment described above, the hydrogen concentration of the purge gas supplied to the fuel cell stack 10 is the mixed gas of the purge gas supplied to the fuel cell stack 10 and the fuel gas expelled. Is supplied to the fuel gas side of the fuel cell stack 10 to supply a large amount of oxidizing gas to the fuel gas side of the fuel cell stack 10. Therefore, the operation of the fuel cell stack 10 can be stopped by a small amount of purge gas. In particular, since air can be used as the oxidizing gas, the cost required to stop the fuel cell system 1 can be reduced. Moreover, since a large amount of oxidizing gas is supplied, even if methanol contained in the fuel gas is condensed on the inner wall of the fuel cell stack 10, the methanol can be vaporized and discharged from the fuel cell stack 10. As a result, methanol is liquefied in the fuel cell stack 10, and the liquefied methanol can be prevented from penetrating into the joined body of the electrolyte membrane 61, the anode 62 and the cathode 63 and separating the joined body. .

The fuel cell system 1 according to the second embodiment
In B, since the fuel cell stack 10 is stopped with the fuel gas side filled with the oxidizing gas, when the fuel cell stack 10 is started to operate, the fuel cell stack 1 is immediately stopped.
Fuel gas cannot be supplied to zero. Therefore, the electronic control unit 5 of the fuel cell system 1B of the second embodiment is
At 0, when the operation of the fuel cell stack 10 is started, the operation start control routine illustrated in FIG. 7 is executed. This routine will be briefly described. When this routine is executed,
The CPU 52 first opens the solenoid valve 38 to supply the purge gas to the fuel cell stack 10 (step S22).
0), after a predetermined time T1 has elapsed (step S22
2) The electromagnetic valve 38 is closed to stop the supply of purge gas (step S224). Then, the electromagnetic valve 32 is opened to start the supply of the fuel gas to the fuel cell stack 10 (step S226), and the present routine is ended.

Thus, steps S220 to S22
By performing the process of 4, the operation of the fuel cell stack 10 can be started. The predetermined time T1 in this routine is the same as the predetermined time T1 in the operation stop control routine.

The processing of steps S220 to S224 of the operation start control routine may be performed not when the fuel cell stack 10 is started but when the fuel cell stack 10 is stopped. That is, these processes are performed in step S2 of the operation stop control routine shown in FIG.
The configuration may be performed after 12.

In the fuel cell system 1B of the second embodiment,
The supply of the purge gas to the fuel cell stack 10 is set to the predetermined time T1. However, as described in the modification of the fuel cell system 1 of the first embodiment, at the confluence point of the fuel gas supply passage 22 with the purge gas supply passage 28. A flow meter is provided downstream or in the purge gas supply passage 28, and even if hydrogen, which is a mixed gas of the purge gas and the fuel gas in the fuel cell stack 10, supplies the oxidizing gas to the fuel cell stack 10, oxygen in the oxidizing gas and the mixed gas are mixed. The supply amount of the purge gas required to reach a concentration equal to or lower than the concentration at which an explosion does not occur due to hydrogen in the atmosphere is obtained in advance by experiments or the like, and this is set as a predetermined amount in the ROM 5
4, the electromagnetic valve 38 may be closed when the supply amount obtained by integrating the flow rate detected by the flow meter reaches the predetermined amount.

Similarly, for a predetermined time T2 of supplying the oxidizing gas, a flow meter is provided in the oxidizing gas communication passage 43 to sufficiently discharge the purge gas and the remaining fuel gas in the fuel cell stack 10 from the fuel cell stack 10. The fuel cell stack 10 is stopped when the fuel gas is supplied with a fuel gas containing the maximum concentration of methanol that the fuel cell stack 10 allows, which is equal to or more than the supply amount of the oxidizing gas required for the fuel cell stack 10. At this time, the supply amount of the oxidizing gas sufficient to vaporize all the methanol condensed on the inner wall of the fuel cell stack 10 to be discharged from the fuel cell stack 10 is obtained in advance by experiments or the like, and this is set as a predetermined amount in the ROM.
The solenoid valve 49 may be closed when it is stored in 54 and the supply amount obtained by integrating the flow rate detected by the flow meter reaches the predetermined amount.

Next, a fuel cell system 1C according to a third embodiment of the present invention will be described. FIG. 8 shows a third embodiment of the present invention.
It is a block diagram which illustrates the outline of composition of fuel cell system 1C which is an example. As shown in the figure, the fuel cell system 1C according to the third embodiment has a solid polymer type fuel cell stack 10 that receives fuel to generate electricity, a methanol tank 12, a methanol tank, and a water tank 14. A reformer 16 for producing hydrogen-rich gas (fuel gas) from water and an output terminal 11 of the fuel cell stack 10.
A secondary battery 75 capable of supplying electric power to a device (load) such as a motor (not shown) connected to a and 11b, and a switch 76 for switching connection between the fuel cell stack 10, the secondary battery and the device (load). And an electronic control unit 50 that controls the operation of each device. The fuel cell stack 10, the reformer 16, and the electronic control unit 50 included in the fuel cell system 1C of the third embodiment are the same as the first embodiment except that a part of the bypass 29 is not built in the reformer 16. It has the same configuration as the example fuel cell system 1. Therefore, these devices are denoted by the same reference symbols as those assigned to the devices included in the fuel cell system 1 of the first embodiment, and the description thereof is omitted. In addition, the fuel cell system 1C of the third embodiment
As for other devices included in the above, those having the same configuration as the devices included in the fuel cell system 1 of the first embodiment are
The same reference numerals are given and the description thereof is omitted.

The anode gas inlet 10a of the fuel cell stack 10 is connected to the reformer 16 by the fuel gas supply passage 22, and the anode gas outlet 10b is connected to the reformer 16 by the fuel gas discharge passage 24. Has been done. Electromagnetic back pressure valves 72 and 74 are provided in the fuel gas supply passage 22 and the fuel gas discharge passage 24. The electromagnetic back pressure valves 72, 74 are valves that adjust the pressure P of the fuel gas in the fuel cell stack 10 to the set pressure PS set in the electromagnetic back pressure valve 72 and the electromagnetic back pressure valve 74. Electromagnetic back pressure valve 7
2 and 74 are connected to back pressure chambers provided for adjusting the pressure, and are controlled in conjunction with each other. The electromagnetic back pressure valves 72 and 74 are connected to the electronic control unit 5 by a conductive line.
It is connected to 0 and is controlled by the electronic control unit 50.

The cathode side gas inlet 10c of the fuel cell stack 10 is connected to the blower 46 by the oxidizing gas supply passage 42. The exhaust gas on the oxidizing gas side of the fuel cell stack 10 is released to the outside air after water in the exhaust gas is recovered from a cathode side gas outlet 10d via an oxidizing gas exhaust passage 44 by a water recovery device (not shown).

The fuel cell stack 10 has a pressure sensor 1 for detecting the pressure P of the fuel gas in the fuel cell stack 10.
0e is provided. The output terminals 11a and 11b of the fuel cell stack 10 are connected to a device (load) such as a motor (not shown) by a power supply line 78 in which a switch 76 is inserted.

The secondary battery 75 is connected to the switch 76, and by connecting the switch 76 to the output terminals 11a and 11b of the fuel cell stack 10, the power output from the fuel cell stack 10 is changed. To charge.

The switch 76 connects and disconnects the output terminals 11a and 11b of the fuel cell stack 10 and a device (load) such as a motor (not shown), and the secondary battery 75 and the device (load).
Connection and disconnection between the output terminals 11a and 11b of the fuel cell stack 10 and the secondary battery 75,
It is a switching device that switches each independently. This switch 76
Are connected to the electronic control unit 50 by a conductive line and are controlled by the electronic control unit 50.

In the fuel cell system 1C of the third embodiment thus constructed, the pressure P of the fuel gas in the fuel cell stack 10 is adjusted to a predetermined pressure by the electromagnetic back pressure valve 72 and the electromagnetic back pressure valve 74 in the steady operation state. Cage, switch 76
Output terminals 11a and 11b of the fuel cell stack 10
Is connected to a device (load) such as a motor by a power supply line 78. In such a state, the fuel cell stack 1
As in the fuel cell system 1 of the first embodiment, the flow rate of methanol and water supplied from the methanol tank 12 and the water tank 14 to the reformer 16 is controlled by the electronic control unit 50 so that 0 can efficiently and stably generate power. Control of the fuel gas to the burner 16a for heating the reformer 16, control of the supply amount of the oxidizing gas to the fuel cell stack 10, etc. are performed.
Electric power generated in the fuel cell stack 10 is supplied to a device (load) such as a motor connected to the power supply line 78 to the power supply lines 1a and 11b.

In the electronic control unit 50 of the fuel cell system 1C of the third embodiment, when stopping the operation of the fuel cell stack 10, the operation stop control routine illustrated in FIG. 9 is executed. This routine is similar to the operation stop control routine in the fuel cell system 1 of the first embodiment, when the operator gives an instruction to stop the operation of the fuel cell system 1C to the electronic control unit 50 of the fuel cell system 1C. Alternatively, it is executed when any abnormality is detected in the fuel cell system 1.

When this routine is executed, the CPU 52
First, a drive signal is output to the switching unit 76 via the input / output port 58, and switching of the switching unit 76 cuts off the connection between the output terminals 11a and 11b of the fuel cell stack 10 and the device (load). , This output terminal 11a,
11b and the secondary battery 75 are connected (step S30).
0). By this switching, electric power generated thereafter until the fuel cell stack 10 is completely stopped charges the secondary battery 75.

Next, the pressure P of the fuel gas in the fuel cell stack 10 detected by the pressure sensor 10e is read through the input / output port 58 (step S302), and it is determined whether the read pressure P is atmospheric pressure. (Step S304). When the pressure P is the atmospheric pressure, this routine is ended, but immediately after the instruction to stop the operation of the fuel cell stack 10 is made, the pressure P is equal to or higher than the atmospheric pressure, and therefore the routine normally proceeds to the next step S306.

When it is determined in step S304 that the pressure P is not the atmospheric pressure, the predetermined value ΔP is subtracted from this pressure P to calculate the set pressure PS of the fuel gas in the fuel cell stack 10 (step S306). After waiting for a predetermined time (step S308), the process returns to step S302. Here, the predetermined value ΔP is a pressure reduction amount when the pressure P in the fuel cell stack 10 is reduced at predetermined time intervals, and is determined by the structure and capacity of the fuel cell stack 10. When the set pressure PS is set, the electromagnetic back pressure valve 72 and the electromagnetic back pressure valve 74 are drive-controlled so that the pressure P of the fuel gas in the fuel cell stack 10 becomes the set pressure PS. In addition, a predetermined time set after the set pressure PS is set and before returning to step S302 (step S308)
Is set as a time equal to or longer than the time required until the pressure P of the fuel gas in the fuel cell stack 10 is adjusted to the set pressure PS reduced by a predetermined value ΔP. And the capacity, the response of the electromagnetic back pressure valve 72, the electromagnetic back pressure valve 74, and the like.

The processing of steps S302 to S308 is repeatedly executed until the pressure P of the fuel gas in the fuel cell stack 10 becomes atmospheric pressure. From the viewpoint of balancing the pressures on both sides of the electrolyte membrane 61 of the fuel cell stack 10, the pressure of the oxidizing gas is gradually reduced with the depressurization process of the fuel gas, that is, the oxidizing gas supply passage 42 and the oxidizing gas. The gas exhaust passage 44 is also provided with an electromagnetic back pressure valve similar to the electromagnetic back pressure valve 72 and the electromagnetic back pressure valve 74,
It is preferable to perform the same processing as steps S302 to 308 of the operation stop control routine of FIG.

According to the fuel cell system 1C of the third embodiment described above, the pressure P of the fuel gas in the fuel cell stack 10 is gradually reduced to the atmospheric pressure, so that the fuel gas in the fuel cell stack 10 is Most can be discharged from the fuel cell stack 10. Further, since the amount of methanol remaining in the fuel cell stack 10 is extremely small, even if the fuel cell stack 10 cools, the methanol does not condense on its inner wall. As a result, the methanol is condensed in the fuel cell stack 10, and the liquefied methanol permeates the joined body of the electrolyte membrane 61, the anode 62, and the cathode 63, so that the joined body can be prevented from being separated. .

The fuel cell system 1C of the third embodiment
Then, the pressure P of the fuel gas in the fuel cell stack 10 is reduced to the atmospheric pressure. However, since the methanol in the fuel gas does not need to condense on the inner wall of the fuel cell stack 10, the reduced pressure is limited to the atmospheric pressure. Not a thing. Also, the third
In the fuel cell system 1C of the embodiment, the pressure P is gradually reduced, but when the capacity of the fuel cell stack 10 is small, the pressure P is immediately set to the atmospheric pressure, that is, the predetermined time of step S308 elapses. The configuration may not be waited.

Next explained is a fuel cell system 1D according to the fourth embodiment of the invention. FIG. 10 is a block diagram illustrating the schematic configuration of the fuel cell system 1D according to the fourth embodiment of the present invention. As shown in the figure, the fuel cell system 1D of the fourth embodiment has a polymer electrolyte fuel cell stack 10 that receives fuel to generate electric power, a methanol tank 12 that stores methanol and a water tank 14 that stores electricity. The reformer 16 that produces hydrogen-rich gas (fuel gas) from water, the temperature adjustment mechanism 80 that adjusts the temperature of the fuel cell stack 10, and the electronic control unit 50 that controls the operation of each device are provided. Fuel cell stack 10 and reformer 1 included in the fuel cell system 1D of the fourth embodiment
6. The electronic control unit 50 has substantially the same configuration as the fuel cell system 1 of the first embodiment. Therefore, these devices are given the same reference numerals as the devices provided in the fuel cell system 1 of the first embodiment, and detailed description thereof is omitted. Also, regarding the other devices included in the fuel cell system 1D of the fourth embodiment, the same components as those included in the fuel cell system 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Omit it.

The anode side gas inlet 10a of the fuel cell stack 10 is connected to the reformer 16 by the fuel gas supply passage 22, and the anode side gas outlet 10b is connected to the reformer 16 by the fuel gas discharge passage 24. Has been done. The fuel gas supply passage 22 and the fuel gas discharge passage 24 are provided with solenoid valves 32 and 33 which are opening / closing valves.
The upstream side of the electromagnetic valve 32 of the fuel gas supply passage 22 is connected to the downstream side of the electromagnetic valve 33 of the fuel gas discharge passage 24 by a communication passage 23A. An electromagnetic valve 23B, which is an opening / closing valve, is provided in the communication passage 23A. These solenoid valves 32, 33, 23B are connected to the electronic control unit 50 by a conductive line, and receive drive control by the electronic control unit 50.

The fuel cell stack 10 is provided with a temperature sensor 10f for detecting the temperature TF in the fuel cell stack 10. The temperature sensor 10f is connected to the electronic control unit 50.

The cathode side gas inlet 10c of the fuel cell stack 10 is connected to the blower 46 by the oxidizing gas supply passage 42. The exhaust gas on the oxidizing gas side of the fuel cell stack 10 is released to the outside air after water in the exhaust gas is recovered from a cathode side gas outlet 10d via an oxidizing gas exhaust passage 44 by a water recovery device (not shown).

The temperature adjusting mechanism 80 includes a reformer-side heat exchanger 82 incorporated in the reformer 16, a fuel cell-side heat exchanger 86 incorporated in the fuel cell stack 10, and a radiator for exchanging heat with the outside air. And 92. The reformer-side heat exchanger 82 and the fuel cell-side heat exchanger 86 are connected to the reformer-side heat exchanger 82 and the fuel cell-side heat exchanger 86 by a circulation flow path 84 that circulates cooling water. Electromagnetic valves 94 and 95, which are open / close valves, are provided in the respective channels of the circulation channel 84.
Further, a pump 88 for circulating the cooling water in the circulation flow passage 84 is provided between the fuel cell side heat exchanger 86 and the electromagnetic valve 95 in the circulation flow passage 84. The radiator 92 is
The radiator flow passage 90 allows the pump 88 of the circulation flow passage 84.
And the solenoid valve 95, and between the fuel cell side heat exchanger 86 and the solenoid valve 94. Radiator flow passage 90
On both sides of the radiator 92 of the
6,97 are provided.

Next, the operation at the time of starting the operation of the fuel cell stack 10 of the fuel cell system 1D of the fourth embodiment thus constructed will be described based on the operation start control routine of FIG. In the fuel cell system 1D before this routine is executed, the operation of the fuel cell stack 10 is stopped, that is, the solenoid valve 32 of the fuel gas supply passage 22 and the solenoid valve 23B of the communication passage 23A are closed, and the fuel gas is closed. The electromagnetic valve 33 of the discharge passage 24 is opened, and the temperature control mechanism 80
The electromagnetic valves 94 and 95 of the circulation flow path 84 are closed, and the electromagnetic valves 96 and 97 of the radiator flow path 90 are open.

When this routine is executed, the CPU 52
First, the temperature TF in the fuel cell stack 10 detected by the temperature sensor 10f is read through the input / output port 58 (step S400), and the read temperature TF is compared with the predetermined temperature TFS (step S402). Here, the predetermined temperature TFS is set as a temperature equal to or higher than the boiling point TM of methanol at the pressure P of the fuel gas in the steady operation state of the fuel cell stack 10, and in steps S402 to S408 described below, the fuel cell Temperature at the end of heating when heating the stack 10 (step S
408 predetermined temperature TFS). When this routine is executed, first, the temperature TF of the fuel cell stack 10 is thus detected and compared with the predetermined temperature TFS at the end of heating after the operation of the fuel cell stack 10 is stopped. This is because when the operation of the fuel cell stack 10 is started before the fuel cell stack 10 is cooled to a temperature lower than the predetermined temperature TFS, the fuel gas is immediately supplied to the fuel cell stack 10.

Since the fuel cell stack 10 is normally cold, the temperature TF is set to the predetermined temperature T in step S402.
It is determined that the temperature is lower than FS, and a flow path for heating the fuel cell stack 10 is formed (step S404). That is, the electromagnetic valve 33 of the fuel gas discharge passage 24 is closed,
The solenoid valve 23B in the communication passage 23A is opened to open the reformer 16
A fuel gas flow path is formed so that all of the fuel gas produced by the method of FIG. At the same time, the solenoid valves 94, 95 of the circulation flow path 84
Is opened and the electromagnetic valves 96 and 97 of the radiator passage 90 are closed to form a passage of cooling water so that the cooling water circulates between the reformer side heat exchanger 82 and the fuel cell side heat exchanger 86. (Circulation along the route of points A, B, C, D, E, F, G in FIG. 10).

By forming the fuel gas flow path in this manner, all the fuel gas produced by the reformer 16 is supplied to the burner 16a to heat the reformer 16. On the other hand, since the cooling water flow path is formed as described above, the cooling water circulates through the reformer-side heat exchanger 82 and the fuel cell-side heat exchanger 86, and thus is added to the reformer 16. The heat is transferred to the fuel cell stack 10 via the cooling water circulating through the reformer side heat exchanger 82 and the fuel cell side heat exchanger 86, and the fuel cell stack 10 is warmed up.

In this way, the flow path for heating the fuel cell stack 10 is formed, and when the heating of the fuel cell stack 10 starts, the CPU 52 reads the temperature TF of the fuel cell stack 10 detected by the temperature sensor 10f (step S406), read temperature TF and predetermined temperature TF
It is compared with S (step S408). When the temperature TF of the fuel cell stack 10 is lower than the predetermined temperature TFS, it is determined that the temperature at which the fuel cell stack 10 starts to operate is not reached, and the process of reading the temperature TF of the fuel cell stack 10 again (step S406) is executed. To do.

Thus, the temperature T of the fuel cell stack 10 is
The processes of steps S406 and S408 are repeatedly performed until F becomes equal to or higher than the predetermined temperature TFS. A flow path for cooling the cell stack 10 is formed (step S410), supply of fuel gas to the fuel cell stack 10 is started (step S412), and the operation of the fuel cell stack 10 is started. That is, the electromagnetic valve 32 of the fuel gas supply passage 22 and the electromagnetic valve 33 of the fuel gas discharge passage 24 are opened, and the electromagnetic valve 23B of the communication passage 23A is closed, so that the fuel gas produced by the reformer 16 is fed into the fuel cell stack. A fuel gas flow path is formed so that the fuel gas is supplied to the solenoid valve 10.
Is closed and the electromagnetic valves 96 and 97 of the radiator flow path 90 are opened to form a flow path of cooling water so that the cooling water circulates between the fuel cell side heat exchanger 86 and the radiator 92. Since the fuel cell stack 10 in the normal operation state generates heat, the flow path of the cooling water is formed in this way, and the rotation speed of the pump 88 is driven based on the temperature TF of the fuel cell stack 10 detected by the temperature sensor 10f. The temperature TF of the fuel cell stack 10 is controlled to an ideal temperature for the fuel cell stack 10 to efficiently generate power.

According to the fuel cell system 1D of the fourth embodiment described above, the temperature of the fuel cell stack 10 is heated to the predetermined temperature TFS equal to or higher than the boiling point TM of methanol before the fuel gas is supplied to the fuel cell stack 10. Therefore, the fuel gas supplied to the fuel cell stack 10 can be prevented from cooling. As a result, even if the fuel gas contains unreacted methanol, the methanol is not liquefied in the fuel cell stack 10. Further, even if liquefied methanol is present in the fuel cell stack 10 before the start of operation, this methanol is vaporized by heating the fuel cell stack 10. Therefore, with the start of the supply of fuel gas to the fuel cell stack 10, It can be immediately discharged from the fuel cell stack 10. Moreover, the fuel cell stack 10
Can be heated to a temperature close to a steady operation state, and thus stable power can be supplied to the device (load) immediately after the start of operation.

The fuel cell system 1D of the fourth embodiment
Then, the predetermined temperature TFS is set as a temperature equal to or higher than the boiling point TM of methanol at the pressure P of the fuel gas in the steady operation state of the fuel cell stack 10, but the predetermined temperature TFS is set.
Is preferably lower than an ideal temperature for the fuel cell stack 10 to efficiently generate power in a steady operation state so as not to raise the temperature TF of the fuel cell stack 10 too much.

Next explained is a fuel cell system 1E according to the fifth embodiment of the invention. FIG. 12 is a block diagram illustrating the outline of the configuration of a fuel cell system 1E that is the fifth embodiment of the present invention. As shown in the figure, the fuel cell system 1E of the fifth embodiment includes a polymer electrolyte fuel cell stack 10 that receives fuel to generate electricity, a methanol tank 12, and a methanol and water tank 14. A reformer 16 that produces hydrogen-rich gas (fuel gas) from water and a first collector 1 that collects water from the fuel gas-side exhaust gas discharged from the fuel cell stack 10.
00 and a second collector 110 installed in the latter stage of the first collector 100 for collecting methanol from the exhaust gas on the fuel gas side.
And an electronic control unit 50 that controls the operation of each device. The fuel cell stack 10, the reformer 16, and the electronic control unit 5 included in the fuel cell system 1E of the fifth embodiment.
0 has the same configuration as the fuel cell system 1 of the first embodiment. Therefore, for these devices,
The same reference numerals are given to the devices included in the fuel cell system 1 of the embodiment, and the detailed description thereof will be omitted. Also, regarding the other devices included in the fuel cell system 1E of the fifth embodiment, the same components as those of the fuel cell system 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Omit it.

The anode gas inlet 10a of the fuel cell stack 10 is connected to the reformer 16 by the fuel gas supply passage 22, and the anode gas outlet 10b is connected to the reformer 16 by the fuel gas discharge passage 24. Has been done. The fuel gas discharge passage 24 has a first space between the reformer 16 and
The collection device 100 and the second collection device 110 are inserted in the series.

The fuel cell stack 10 includes a pressure sensor 1 for detecting the pressure P of the fuel gas in the fuel cell stack 10.
0e and a temperature sensor 10f for detecting the temperature TF in the fuel cell stack 10 are provided. This pressure sensor 1
0e and the temperature sensor 10f are connected to the electronic control unit 50 by a conductive line.

The cathode side gas inlet 10c of the fuel cell stack 10 is connected to the blower 46 by the oxidizing gas supply passage 42. The exhaust gas on the oxidizing gas side of the fuel cell stack 10 is released to the outside air after water in the exhaust gas is recovered from a cathode side gas outlet 10d via an oxidizing gas exhaust passage 44 by a water recovery device (not shown).

The first collector 100 has a temperature equal to or higher than the boiling point TM of methanol at the pressure P of the fuel gas in the fuel cell stack 10 in the steady operation state and lower than the boiling point of water at the pressure P. It is a constant temperature tank adjusted to a predetermined temperature TWS, and collects water by condensing water in the exhaust gas on the fuel gas side at this temperature. Although not shown, the first recovery device 100 includes a temperature sensor that detects the temperature inside the first recovery device 100 and a temperature adjustment device that adjusts the temperature inside the first recovery device 100. The electronic control unit 50 drives and controls the temperature adjusting device based on the temperature detected by the sensor, so that the inside of the first recovery unit 100 is constantly adjusted to the predetermined temperature TWS. Further, the first recovery device 100 is connected to the water tank 14 by a first recovery flow path 102 provided with an electromagnetic valve 104 which is an opening / closing valve, and by opening / closing the electromagnetic valve 104, the first recovery device 100 is operated. The recovered water is returned to the water tank 14.

In the first recovery unit 100, the predetermined temperature TWS, which is the adjusted temperature of the first recovery unit 100, is set to be equal to or higher than the boiling point TM of methanol so that the methanol in the exhaust gas is not condensed and is lower than the boiling point of water. As a result, only the water in the exhaust gas can be condensed.

The second collector 110 is a constant temperature tank adjusted to a predetermined temperature TMS which is lower than the boiling point TM of methanol at the pressure P of the fuel gas in the fuel cell stack 10 in the steady operation state. It collects by condensing the methanol in the exhaust gas discharged from the collector 100. Although not shown, the second recovery unit 110, like the first recovery unit 100, has a temperature sensor for detecting the temperature inside the second recovery unit 110 and a temperature adjusting device for adjusting the temperature inside the second recovery unit 110. And the electronic control unit 50 drives and controls the temperature adjusting device based on the temperature detected by the temperature sensor.
The inside of 10 is always adjusted to a predetermined temperature TMS. In addition, the second recovery device 110 is a solenoid valve 1 that is an opening / closing valve.
The second recovery flow path 112 provided with 14 is connected to the methanol tank 12, and the solenoid valve 114 is opened and closed to return the methanol recovered by the second recovery device 110 to the methanol tank 12.

In such a second recovery device 110, the predetermined temperature TMS, which is the adjusted temperature of the second recovery device 110, is set below the boiling point TM of methanol, so that the methanol in the exhaust gas that has not condensed in the first recovery device 100 is Can be condensed. Since the predetermined temperature TMS that is the adjustment temperature of the second recovery device 110 is lower than the predetermined temperature TWS that is the adjustment temperature of the first recovery device 100, the exhaust gas discharged from the first recovery device 100 is saturated at the predetermined temperature TWS. In the second recovery device 110, which contains water vapor, a part of the saturated water vapor is condensed,
The condensed water is mixed with the methanol recovered in the second recovery device 110. As described above, even if some amount of water is mixed in the methanol recovered by the second recovery unit 110, the recovered methanol is returned to the methanol tank 12 and is supplied to the reformer 16 from the methanol tank 12 with water. Since it is mixed with water from the tank 14 and vaporized, it does not affect the operation of the reformer 16.

The exhaust gas discharged from the second recovery unit 110 is sent to the burner 16a of the reformer 16 and the hydrogen in the exhaust gas is burned.

According to the fuel cell system 1E of the fifth embodiment described above, water is recovered from the exhaust gas on the fuel gas side discharged from the fuel cell stack 10 by the first recovery device 100 and the second recovery device is recovered. The methanol can be recovered at 110 and returned to the water tank 14 and the methanol tank 12, respectively, and it is possible to prevent methanol from being mixed in the water system of the system. As a result, it is possible to avoid inconveniences such as corrosion of pipes of the water system and deterioration of strength due to the mixture of methanol in the water system of the system. Therefore, it is not necessary to use materials such as pipes of the water system of the system that are resistant to methanol.

Incidentally, the fuel cell system 1E of the fifth embodiment.
Then, the first collector 100 and the second collector 110 are inserted in the fuel gas discharge passage 24 of the fuel cell stack 10 to separate water and methanol from the fuel gas side exhaust gas discharged from the fuel cell stack 10. However, the first and second collectors 100 and 110 are inserted into the oxidizing gas discharge passage 44 to separate water and methanol from the oxidizing gas side exhaust gas discharged from the fuel cell stack 10 and collect them. It may be configured to.

Next, a fuel cell system 1F which is a sixth embodiment of the present invention will be described. FIG. 13 is a block diagram illustrating a part of the configuration of the fuel cell system 1F according to the sixth embodiment of the present invention. As shown in the figure, the fuel cell system 1E according to the fifth embodiment has the same configuration as the fuel cell system 1E according to the fifth embodiment, as well as the fuel cell stack 1
The oxidation reactor 120 that oxidizes methanol mixed in the exhaust gas on the oxidizing gas side discharged from 0 and the third recovery unit 130 that recovers water contained in the exhaust gas on the oxidizing gas side. Therefore, the fuel cell system 1E of the sixth embodiment
The same configurations as those of the fuel cell system 1E of the fifth embodiment among the above configurations are denoted by the same reference numerals, and the description thereof will be omitted.

In the oxidizing gas discharge passage 44 connected to the cathode side gas outlet 10d of the fuel cell stack 10, an oxidation reactor 120 and a third collector 130 are inserted in series.

FIG. 14 is an explanatory view illustrating the outline of the structure of the oxidation reactor 120. The oxidation reactor 120 includes a cylindrical main body 121, and a honeycomb-shaped honeycomb tube 122 having a space on the inlet side and the outlet side inside the main body 121 and having a platinum catalyst supported on the surface thereof. . An exhaust gas temperature sensor 124 for detecting the temperature TG of the exhaust gas introduced into the oxidation reactor 120 is provided in the space inside the oxidation reactor 120 on the inlet side. A catalyst temperature sensor 126 that detects the temperature TS is provided. The exhaust gas temperature sensor 124 and the catalyst temperature sensor 126 are connected to the electronic control unit 50 by a conductive line.

The third collector 130 is a constant temperature tank adjusted to a predetermined temperature TW3 lower than the boiling point of water at the pressure P of the exhaust gas in the fuel cell stack 10 in the steady operation state, and the fuel cell stack at this temperature. The water in the exhaust gas on the side of the oxidizing gas discharged from 10 is collected by condensing. Although not shown, the third collector 130 also has a temperature sensor for detecting the temperature in the third collector 130 and the third collector 130, as in the first collector 100 included in the fuel cell system 1E of the fifth embodiment. A temperature control device for controlling the temperature inside the electronic device, and the electronic control unit 50 drives and controls the temperature control device based on the temperature detected by the temperature sensor, so that the inside of the third recovery unit 130 is always kept at a predetermined level. The temperature is adjusted to TW3. In addition, the third recovery unit 130 has a third valve provided with an electromagnetic valve 134 that is an opening / closing valve.
Connected to the water tank 14 by a recovery channel 132,
The water recovered by the third recovery device 130 is returned to the water tank 14 by opening and closing the electromagnetic valve 134. The oxidation reactor 1
The exhaust gas discharged from 20 does not contain methanol because methanol is completely oxidized in the oxidation reactor 120, and the water recovered in the third recovery device 130 does not contain methanol. .

Next, the fuel cell system 1F of the sixth embodiment thus constructed will be described. The operation in the steady operation state will be described based on the methanol concentration control routine of FIG. In the fuel cell system 1F, the methanol tank 12 and the water tank 14 are controlled by the electronic control unit 50 so that the fuel cell stack 10 efficiently generates electric power.
Control of the supply flow rate of methanol and water from the reformer 16 to the reformer 16, control of the supply amount of fuel gas to the burner 16a that heats the reformer 16, temperature control of the fuel cell stack 10, first recovery unit 100, 2 collector 110 and 3rd collector 1
Temperature control of each of the 30 is performed. Among these controls, the control based on the concentration of methanol contained in the fuel gas will be described based on the methanol concentration control routine shown in FIG. This routine is executed, for example, at every predetermined time (for example, every 10 msec) in the steady operation state after the operation of the fuel cell system 1F is started.

When the methanol concentration control routine is executed, the CPU 52 causes the temperature TG of the exhaust gas on the oxidizing gas side detected by the exhaust gas temperature sensor 124 and the honeycomb tube 122 detected by the catalyst temperature sensor 126.
The temperature TS of the platinum catalyst carried on the surface of the is read via the input / output port 58 (step S500). Subsequently, the deviation ΔT is calculated by subtracting the exhaust gas temperature TG from the platinum catalyst temperature TS (step S502), and the calculated deviation ΔT is compared with the threshold value TR (step S504).

When the unreacted methanol in the reformer 16 is mixed in the fuel gas supplied to the fuel cell stack 10 when the fuel cell stack 10 is in the steady operation state,
This methanol permeates the electrolyte membrane 61 from the fuel gas side to the oxidizing gas side. This permeation amount increases as the concentration of methanol in the fuel gas increases. In the fuel cell system 1F of the sixth embodiment, the oxidizing gas side exhaust gas discharged from the fuel cell stack 10 is guided to the oxidation reactor 120, and the platinum catalyst is carried on the surface of the honeycomb tube 122 of the oxidation reactor 120. Therefore, when the exhaust gas on the oxidizing gas side contains methanol, the methanol is oxidized on the platinum catalyst to generate heat. Therefore, when methanol is contained in the exhaust gas on the oxidizing gas side, a deviation ΔT is present between the exhaust gas temperature TG detected by the exhaust gas temperature sensor 124 and the platinum catalyst temperature TS detected by the catalyst temperature sensor 126. Will occur. This deviation ΔT
Reflects the reaction amount of methanol on the platinum catalyst of the oxidation reactor 120, that is, the concentration of methanol in the exhaust gas on the oxidizing gas side, and the concentration of methanol in the exhaust gas on the oxidizing gas side is the concentration of methanol in the fuel gas. Therefore, the deviation ΔT reflects the methanol concentration in the fuel gas.

Here, the threshold value TR is set to the fuel cell stack 1
The deviation ΔT between the exhaust gas temperature TG and the platinum catalyst temperature TS detected when the fuel gas having an allowable methanol concentration of 0 (for example, 1 mol%) is supplied to the fuel cell stack 10 in the steady operation state. Then, comparing the deviation ΔT in step S504 with the threshold value TR determines whether or not the methanol concentration in the fuel gas is equal to or lower than the allowable concentration.

Therefore, when the deviation ΔT is smaller than the threshold value TR, it is determined that the methanol concentration in the fuel gas is below the allowable concentration, and the target operating temperature of the reformer 16 is temperature controlled by the electronic control unit 50. Target temperature TK
Set a predetermined temperature TK1 to M (step S506),
When this routine is finished and the deviation ΔT is equal to or larger than the threshold value TR, it is determined that the methanol concentration in the fuel gas exceeds the allowable concentration, and the target temperature TKM is set to a predetermined temperature TK2 higher than the predetermined temperature TK1. (Step S106), this routine is ended.

Here, in the temperature control of the reformer 16 by the electronic control unit 50, specifically, the deviation between the temperature detected by the temperature sensor (not shown) provided in the reformer 16 and the target temperature TKM is This is performed by adjusting the amount of fuel gas supplied to the burner 16a so as to be small.
The predetermined temperature TK1 is the operating temperature of the reformer 16 in the steady operation state of the fuel cell system 1F, and is determined by the allowable concentration of methanol in the fuel cell stack 10 and the performance of the reformer 16. In the sixth embodiment, this predetermined temperature TK1 is set to a temperature of 250 ° C to 300 ° C. The predetermined temperature TK2 is equal to the predetermined temperature TK1.
The temperature is set higher by 5 to 40 ° C.

According to the fuel cell system 1F of the sixth embodiment described above, heat generated by oxidizing methanol contained in the exhaust gas on the oxidizing gas side discharged from the fuel cell stack 10 in the oxidation reactor 120 is used. Based on this, by adjusting the operating temperature of the reformer 16, the concentration of methanol in the fuel gas can be controlled to be equal to or lower than the allowable concentration. As a result, it is possible to prevent a decrease in the output from the fuel cell stack 10 due to an increase in the concentration of methanol in the fuel gas, and it is possible to further increase the operating efficiency of the entire system.

Further, since the methanol contained in the oxidizing gas side exhaust gas discharged from the fuel cell stack 10 is completely oxidized in the oxidation reactor 120, the water recovered in the third recovery device 130 contains methanol. Can be prevented. As a result, it is possible to avoid inconveniences such as corrosion of pipes of the water system and deterioration of strength due to the mixture of methanol in the water system of the system. Therefore,
It is not necessary to use methanol-resistant materials for the piping of the water system of the system.

Next, a fuel cell system 1G according to a seventh embodiment of the present invention will be described. FIG. 16 is a block diagram illustrating the outline of the configuration centering on the water system of the fuel cell system 1G according to the seventh embodiment of the present invention. As shown in the figure, the fuel cell system 1G of the seventh embodiment has a polymer electrolyte fuel cell stack 10 that receives fuel to generate power, a methanol tank 12, and a methanol and water tank 14. A reformer 16 that produces hydrogen-rich gas (fuel gas) from the water, an anode-side water collector 210 that collects water from the fuel gas-side exhaust gas discharged from the fuel cell stack 10, and a fuel cell stack 10 A humidifier 230 for humidifying the oxidizing gas supplied to
A cathode side water collector 240 that collects water from the oxidizing gas side exhaust gas discharged from the fuel cell stack 10, and a temperature adjusting mechanism 22 that adjusts the temperature of the fuel cell stack 10.
0, and an oxidation reactor 250 that oxidizes the methanol contained in the water collected by the anode-side water collector 210 and the cathode-side water collector 240, respectively. The fuel cell stack 10 and the reformer 16 included in the fuel cell system 1G of the seventh embodiment have the same configuration as the fuel cell system 1 of the first embodiment. Therefore, these devices are given the same reference numerals as the devices provided in the fuel cell system 1 of the first embodiment, and detailed description thereof is omitted. In addition, the fuel cell system 1 of the seventh embodiment
Regarding other devices included in G, the same components as those included in the fuel cell system 1 of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The anode gas inlet 10a of the fuel cell stack 10 is connected to the reformer 16 by the fuel gas supply passage 22, and the anode gas outlet 10b is connected to the reformer 16 by the fuel gas discharge passage 24. Has been done. In the fuel gas discharge passage 24, an anode side water recovery device 210 is inserted between the fuel gas discharge passage 24 and the reformer 16.

The cathode side gas inlet 10c of the fuel cell stack 10 is connected to the blower 46 by the oxidizing gas supply passage 42, and the humidification is provided between the fuel cell stack 10 and the blower 46 in the oxidizing gas supply passage 42. A device 230 is provided. The cathode side gas outlet 10d is connected to the cathode side water recovery device 240 through the fuel gas discharge passage 24.

The temperature adjusting mechanism 220 comprises a heat exchanger 222 built in the fuel cell stack 10 and a radiator 226 for exchanging heat with the outside air. The heat exchanger 222 and the radiator 226 are connected to the heat exchanger 222 and the radiator 226 by a circulation flow path 224 that circulates cooling water. The circulation channel 224 is provided with a pump 228 that circulates the cooling water in the circulation channel 224. The temperature adjustment mechanism 220 adjusts the flow rate of the cooling water circulating through the circulation passage 224 by the pump 228 based on the temperature detected by a temperature sensor (not shown) that detects the temperature of the fuel cell stack 10, thereby performing heat exchange. The fuel cell stack 10 is controlled to a preset temperature by adjusting the amount of heat exchanged by the container 222 and the radiator 226. The circulation flow path 224 of the temperature control mechanism 220 is connected to the water tank 14 by a replenishment flow path 229, and the water shortage is replenished from the water tank 14 via the replenishment flow path 229.

The humidifier 230 humidifies the oxidizing gas by bubbling or spraying water. The humidifier 230 is connected to the water tank 14 via a replenishment flow path 232, and receives replenishment of water from the water tank 14 via the replenishment flow path 232.

The anode side water recovery unit 210 is a constant temperature tank adjusted to a predetermined temperature TA which is lower than the boiling point of water at the pressure P of the fuel gas in the fuel cell stack 10 in the steady operation state. The methanol in the exhaust gas discharged from the water recovery unit 210 is recovered by being condensed. Although not shown, the anode-side water collector 210 is similar to the first collector 100 included in the fuel cell system 1E of the fifth embodiment.
Sensor for detecting the temperature of the anode and the water recovery device 2 on the anode side
And a temperature adjusting device for adjusting the temperature of 10 and the temperature adjusting device adjusts the inside of the anode-side water recovery unit 210 to a predetermined temperature TA at all times based on the temperature detected by the temperature sensor. . Further, the anode side water recovery unit 210 is connected to the oxidation reactor 250 by an anode side recovery flow passage 212 provided with an electromagnetic valve 214 which is an opening / closing valve, and the anode side water recovery is performed by opening / closing the electromagnetic valve 214. The water recovered in the vessel 210 is used in the oxidation reactor 25
Send to 0.

The cathode side water recovery device 240 has the same structure as the anode side water recovery device 210. Further, the cathode-side water recovery device 240 uses the cathode-side recovery flow path 242 provided with the solenoid valve 244, which is an opening / closing valve, to oxidize the reactor
50 is connected to the oxidation reactor 250 by opening and closing the solenoid valve 244.

The inside of the oxidation reactor 250 is provided with a member 252 such as a honeycomb tube having a large surface area so that the supplied water spreads on its surface and comes into sufficient contact with the atmosphere. A platinum catalyst is carried on the surface of the member 252. Further, the oxidation reactor 250 is
The air introduction passage 254 is connected to the blower 256, and a sufficient amount of atmosphere is introduced through the air introduction passage 254. The water sent to the oxidation reactor 250 is
The water flows along the surface of 52 while coming into contact with the atmosphere, and is sent to the water tank 14. If the water sent to the oxidation reactor 250 contains methanol, it is oxidized on the platinum catalyst carried on the surface of the member 252 while the water is traveling on the surface of the member 252 while being in contact with the atmosphere. As a result, the methanol of the water sent to the water tank 14 is completely oxidized, and the water in the water tank 14 does not contain methanol.

In the fuel cell system 1G of the seventh embodiment thus constructed, the methanol tank 12 and the water tank 14 are arranged so that the fuel cell stack 10 can efficiently generate electricity.
Control of the supply flow rate of methanol and water from the reformer 16 to the reformer 16, control of the supply amount of fuel gas to the burner 16a for heating the reformer 16, temperature control of the fuel cell stack 10 by the temperature adjustment mechanism 220, humidifier The humidification amount is controlled by 230, the temperature of each of the anode side water recovery unit 210 and the cathode side water recovery unit 240 is controlled, and the amount of air introduced into the oxidation reactor 250 is controlled.

According to the fuel cell system 1G of the seventh embodiment described above, the methanol contained in the water collected by the anode side water recovery unit 210 and the cathode side water recovery unit 240 is oxidized by the oxidation reactor 250. Can be removed. As a result, it is possible to avoid inconveniences such as corrosion of pipes of the water system and deterioration of strength due to the mixture of methanol in the water system of the system.
Therefore, it is not necessary to use materials such as pipes of the water system of the system that are resistant to methanol.

The fuel cell system 1G of the seventh embodiment
The oxidation reactor 250 included in can be included in the fuel cell system 1E of the fifth embodiment and the fuel cell system 1F of the sixth embodiment described above. As described above, if the fuel cell system 1E of the fifth embodiment and the fuel cell system 1F of the sixth embodiment include the oxidation reactor 250, it is possible to more reliably prevent the mixture of methanol in the water system of the system. .

The embodiments of the present invention have been described above.
The present invention is not limited to these examples, and for example, a configuration in which a plurality of configurations included in each of the fuel cell systems of the first to seventh examples is combined, and the like without departing from the gist of the present invention. It is needless to say that the above can be implemented in various modes.

[0146]

As described above, according to the fuel cell system of the first aspect of the present invention, when the operation of the fuel cell is stopped, the non-reactive gas is supplied to the fuel cell instead of the fuel gas. The methanol contained in the fuel gas together with the fuel gas can be discharged to the outside of the fuel cell. Moreover, since the non-reactive gas supplied to the fuel cell is heated above the boiling point of methanol, methanol contained in the fuel gas does not condense, that is, liquefy. As a result, it is possible to prevent the inconvenience of separating the joined body of the electrolyte membrane and the electrode due to liquefaction and residual of methanol.

According to the fuel cell system of the second aspect, when the operation of the fuel cell is stopped, a predetermined amount of non-reactive gas is supplied to the fuel cell instead of the fuel gas, so that it is included in the fuel gas together with the fuel gas. The generated methanol can be discharged to the outside of the fuel cell. Moreover, since the oxidizing gas is supplied in place of the non-reactive gas after supplying the predetermined amount of the non-reactive gas, the supplied oxidizing gas does not react with the fuel gas remaining in the fuel cell, and Methanol can be reliably discharged from the fuel cell, and the supply amount (predetermined amount) of the non-reactive gas can be reduced.

According to the fuel cell system of the third aspect, when the operation of the fuel cell is stopped, the pressures of the fuel gas and the oxidizing gas in the fuel cell are changed in accordance with the stop of the supply of the fuel gas to the fuel cell. By gradually decreasing the temperature, the fuel gas expands and the liquefaction temperature of methanol decreases, so that the methanol contained in the fuel gas together with the fuel gas can be discharged to the outside of the fuel cell and the methanol liquefies in the fuel cell. Can be prevented.

According to the fuel cell system of the fourth aspect, when the fuel cell is started, the fuel cell is heated to a temperature equal to or higher than the boiling point of methanol, and then the supply of the fuel gas to the fuel cell is started. It is possible to prevent the disadvantage that the fuel gas is cooled by the cooled fuel cell immediately after and the methanol in the fuel gas is liquefied in the fuel cell. Further, even when liquefied methanol exists in the fuel cell, this methanol can be vaporized and discharged from the fuel cell along with the supply of the fuel gas.

According to the fuel cell system of the fifth aspect, methanol-free water is recovered by the first water recovery means set to the first predetermined temperature lower than the operating temperature of the fuel cell and higher than the boiling point of methanol. Thus, the water containing methanol can be recovered by the second water recovery means that is installed in the latter stage of the first water recovery means and is set at the second predetermined temperature lower than the boiling point of methanol. As a result, the water recovered by the first water recovery means is returned to the system water system, and the water recovered by the second water recovery means is not returned to the system water system. Can be prevented from being mixed.

According to the fuel cell system of the sixth aspect, of the exhaust gas discharged from the fuel cell, the methanol contained in the exhaust gas on the oxidizing gas side is oxidized, so that the methanol is excluded from the exhaust gas on the oxidizing gas side. can do. As a result, even if water is recovered from the exhaust gas on the oxidizing gas side and returned to the system water system, methanol is not mixed in the system water system.

According to the fuel cell system of the seventh aspect, when the concentration of methanol in the fuel gas increases, more of the methanol permeates to the oxidizing gas side, and when the methanol in the exhaust gas is oxidized by the oxidizing means. The concentration of methanol in the fuel gas can be estimated by obtaining the temperature of the exhaust gas on the oxidizing gas side and the temperature of the oxidizing means based on the heat generation. As a result, the concentration of methanol in the fuel gas can be controlled based on these temperatures.

According to the fuel cell system of the eighth aspect, when the deviation between the temperature of the exhaust gas on the oxidizing gas side and the temperature of the oxidizing means becomes a predetermined value or more, the operating temperature of the reformer is ideally operated. Since the temperature is higher than the predetermined temperature, the decomposition reaction of hydrogen is promoted by raising the operating temperature of the reformer, and as a result, the concentration of methanol in the fuel gas can be lowered.

According to the ninth aspect of the fuel cell system, since the methanol contained in the water recovered by the water recovery means is oxidized, the methanol can be removed from the recovered water. As a result, even if the recovered water is returned to the system water system, methanol will not be mixed in the system water system.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a fuel cell system 1 that is a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating the outline of the configuration of each cell that constitutes the fuel cell stack 10.

FIG. 3 is a flowchart showing an example of an operation stop control routine executed by a CPU 52 of an electronic control unit 50.

FIG. 4 is a flowchart showing an example of a purge gas temperature control routine executed by a CPU 52 of the electronic control unit 50.

FIG. 5 is a fuel cell system 1 according to a second embodiment of the present invention.
It is a block diagram which illustrates the outline of a structure of B.

FIG. 6 is a flowchart showing an example of an operation stop control routine executed by the electronic control unit 50 of the fuel cell system 1B of the second embodiment.

FIG. 7 is a flowchart showing an example of an operation start control routine executed by the electronic control unit 50 of the fuel cell system 1B of the second embodiment.

FIG. 8 is a fuel cell system 1 according to a third embodiment of the present invention.
It is a block diagram which illustrates the outline of a structure of C.

FIG. 9 is a flowchart showing an example of an operation stop control routine executed by the electronic control unit 50 of the fuel cell system 1C of the third embodiment.

FIG. 10 is a block diagram illustrating a schematic configuration of a fuel cell system 1D according to a fourth embodiment of the present invention.

FIG. 11 is a flowchart showing an example of an operation start control routine executed by the electronic control unit 50 of the fuel cell system 1D of the fourth embodiment.

FIG. 12 is a block diagram illustrating a schematic configuration of a fuel cell system 1E that is a fifth embodiment of the present invention.

FIG. 13 is a block diagram illustrating a part of the configuration of a fuel cell system 1F that is a sixth embodiment of the present invention.

FIG. 14 is an explanatory diagram illustrating the schematic configuration of an oxidation reactor 120 included in a fuel cell system 1F according to a sixth embodiment.

FIG. 15 is a flowchart showing an example of a methanol concentration control routine executed by the electronic control unit 50 of the fuel cell system 1F of the sixth embodiment.

FIG. 16 is a block diagram illustrating a schematic configuration of a fuel cell system 1G that is a seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 1B-1G ... Fuel cell system 10 ... Fuel cell stack 10a ... Anode side gas inlet 10b ... Anode side gas outlet 10c ... Cathode side gas inlet 10d ... Cathode side gas outlet 10e ... Pressure sensor 10f ... Temperature sensor 11a , 11b ... Output terminal 12 ... Methanol tank 14 ... Water tank 16 ... Reformer 16a ... Burner 20 ... Purge gas tank 22 ... Fuel gas supply passage 23A ... Communication passage 23B ... Solenoid valve 24 ... Fuel gas discharge passage 26 ... Exhaust passage 28 ... Purge gas supply passage 29 ... Detour 32, 33, 38, 48, 49 ... Electromagnetic valve 34 ... Flow control valve 36 ... Purge gas temperature sensor 42 ... Oxidation gas supply passage 43 ... Oxidation gas communication passage 44 ... Oxidation gas discharge passage 46 ... Blower 50 ... Electronic control unit 52 ... CPU 54 ... RO M 56 ... RAM 58 ... Input / output port 59 ... Timer 61 ... Electrolyte membrane 62 ... Anode 63 ... Cathode 64, 65 ... Separator 64p ... Flow channel groove 65p ... Flow channel groove 66, 67 ... Current collecting plate 72, 74 ... Electromagnetic back Pressure valve 76 ... Switcher 78 ... Power supply line 80 ... Temperature control mechanism 82 ... Reformer side heat exchanger 84 ... Circulating flow path 86 ... Fuel cell side heat exchanger 88 ... Pump 90 ... Radiator flow path 92 ... Radiator 94, 95, 96, 97 ... Electromagnetic valve 100 ... First recovery device 102 ... First recovery flow path 104, 114 ... Electromagnetic valve 110 ... Second recovery device 112 ... Second recovery flow path 120 ... Oxidation reactor 121 ... Main body 122 ... Honeycomb tube 124 ... Exhaust gas temperature sensor 126 ... Catalyst temperature sensor 130 ... Third recovery device 132 ... Third recovery flow path 134 ... Electromagnetic valve 210 ... Anode side water recovery device 12 ... Anode side recovery flow paths 214, 244 ... Electromagnetic valve 220 ... Temperature control mechanism 222 ... Heat exchanger 224 ... Circulation flow path 226 ... Radiator 228 ... Pump 229 ... Replenishment flow path 230 ... Humidifier 232 ... Replenishment flow path 240 ... Cathode-side water recovery device 242 ... Cathode-side recovery flow channel 250 ... Oxidation reactor 252 ... Member 254 ... Atmosphere introduction passage 256 ... Blower

Claims (9)

[Claims] 1. A fuel cell system comprising a fuel cell, which uses hydrogen as a fuel gas produced from methanol and water and an oxidizing gas as oxygen as a fuel, to generate electricity by an electrochemical reaction. When stopping the operation of the fuel cell, the fuel gas supply stopping means for stopping the supply of the fuel gas to the fuel cell, and the non-reaction with the fuel gas and the oxidizing gas accompanying the stop of the supply of the fuel gas. Non-reactive gas supply means for supplying reactive gas to the fuel cell in place of the fuel gas, and the non-reactive gas supplied to the fuel cell by the non-reactive gas supply means to at least the boiling point of methanol. A fuel cell system comprising: heating means for heating. 2. A fuel cell system comprising a fuel cell for generating electricity by an electrochemical reaction using a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen as fuels, When stopping the operation of the fuel cell, the fuel gas supply stopping means for stopping the supply of the fuel gas to the fuel cell, and the non-reaction with the fuel gas and the oxidizing gas accompanying the stop of the supply of the fuel gas. A non-reactive gas supply means for supplying a predetermined amount of the reactive gas to the fuel cell instead of the fuel gas, and a predetermined amount of the non-reactive gas supplied to the fuel cell by the non-reactive gas supply means A fuel cell system comprising: an oxidizing gas supply unit that supplies the oxidizing gas to the fuel cell instead of the non-reactive gas. 3. A fuel cell system comprising a fuel cell for generating electric power by an electrochemical reaction using a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen as fuel. When stopping the operation of the fuel cell, a fuel gas supply stopping means for stopping the supply of the fuel gas to the fuel cell, and the stop of the supply of the fuel gas, the fuel gas and the oxidizing gas in the fuel cell A fuel cell system comprising a pressure reducing means for gradually lowering the pressure. 4. A fuel cell system comprising a fuel cell, which uses a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen as fuels to generate electricity by an electrochemical reaction, Heating means for heating the fuel cell to at least the boiling point of methanol when starting the fuel cell; and fuel gas supply for starting the supply of the fuel gas to the fuel cell after the fuel cell is heated by the heating means. A fuel cell system including a starting means. 5. A fuel cell for generating electric power by an electrochemical reaction using a fuel gas containing hydrogen produced from methanol and water and an oxidizing gas containing oxygen as fuels, and an exhaust gas discharged from the fuel cell. In a fuel cell system including a water recovery means for recovering water, the water recovery means is a first water recovery means set to a first predetermined temperature lower than an operating temperature of the fuel cell and higher than a boiling point of methanol. And a second water recovery means installed at a stage subsequent to the first water recovery means and set to a second predetermined temperature lower than the boiling point of methanol. 6. A reformer for producing a fuel gas containing hydrogen from methanol and water, and a fuel cell for producing electricity by an electrochemical reaction using the produced fuel gas and an oxidizing gas containing oxygen as fuel. A fuel cell system comprising: an oxidizing unit that oxidizes methanol contained in the exhaust gas on the oxidizing gas side of the exhaust gas discharged from the fuel cell. 7. The fuel cell system according to claim 6, wherein an exhaust gas temperature detecting means for detecting a temperature of the exhaust gas on the oxidizing gas side, an oxidizing temperature detecting means for detecting a temperature of the oxidizing means, Control for controlling the operation of the reformer so as to reduce the concentration of methanol in the fuel gas based on the temperature detected by the exhaust gas temperature detection means and the temperature detected by the oxidation temperature detection means. A fuel cell system comprising: 8. The reformer of the reformer when the deviation between the temperature detected by the exhaust gas temperature detecting means and the temperature detected by the oxidation temperature detecting means is equal to or more than a predetermined value. The fuel cell system according to claim 7, which is a means for controlling the operating temperature to a predetermined temperature higher than the ideal operating temperature. 9. A fuel cell that generates electricity by an electrochemical reaction using a fuel gas containing hydrogen generated from methanol and water and an oxidizing gas containing oxygen as fuel, and an exhaust gas discharged from the fuel cell. A fuel cell system comprising a water recovery means for recovering water, the fuel comprising an oxidation means which is provided after the water recovery means and which oxidizes methanol contained in the water recovered by the water recovery means. Battery system.