JP2001229951A - Fuel-cell system for moving object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel-cell system for moving objects, that can reduce residual hydrogen concentration to an extremely low level in a hydrogen circula tion system consisting of the fuel-pole side of a fuel cell and the secondary side of hydrogen separation film, at the time of system suspension, within a short time before the temperature of the hydrogen separation film becomes lower than the hydrogen-embrittlement temperature. SOLUTION: At system suspension, electricity is generated by residual hydrogen, while vapor is circulated in a hydrogen circulation system HLP, consisting of the fuel-pole side of a fuel cell 100 and the secondary side of hydrogen separation film 106. After that, while the vapor is being circulated in the hydrogen circulation system, voltage is applied to the fuel cell 100 from a battery 401, and by electrochemically transporting residual hydrogen which is left in slight amount from the fuel pole to the air pole of the fuel cell, residual hydrogen concentration in the hydrogen circulation system is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile fuel cell system.

[0002]

2. Description of the Related Art A fuel cell system employing a conventional hydrogen separator has a configuration shown in FIG. In this conventional fuel cell system, 100 is a fuel cell, 101 is a reformer that steam reforms methanol 102 using water 103 to generate a hydrogen-rich gas 104,
Reference numeral 105 denotes a hydrogen separator for separating hydrogen from the hydrogen-rich gas 104, reference numeral 106 denotes a hydrogen separation membrane containing palladium as a main component, and reference numeral 108 denotes a hydrogen separator 1 from the hydrogen-rich gas 104.
This is a combustor for burning the exhaust gas 107 from which most of the hydrogen has been separated by 05.

[0003] Pure hydrogen 11 purified by a hydrogen separator 105
0 indicates that water vapor is added by the humidifier 111 and the fuel cell 100
And a part of the hydrogen is consumed by the fuel electrode of the fuel cell 100, steam is collected by the condenser 112, and returned to the hydrogen separator 105 by the pump 112. That is, a hydrogen circulation system HLP is configured.

On the other hand, air 12
1 is sent to the air electrode of the fuel cell 100, where a part of oxygen is consumed, and after the steam is recovered in the condenser 123,
It is sent to a combustor 108 where it is used to burn the exhaust gas 107. The water vapor collected in the condensers 112 and 123 is collected in the water tank 131 as liquid water.

The methanol in the methanol tank 130 and the water in the water tank 131 are sent to the evaporator 109 by the pumps 132 and 133, are vaporized by the heat generated in the combustor 108, and are sent to the reformer 101. The heat generated in the combustor 108 is used in the evaporator 109, a heat source for the endothermic reaction in the reformer 101, and the hydrogen separation membrane 1
It is used for heat retention of 06. If the amount of heat generated in the combustor 108 is insufficient, the methanol tank 1
The methanol in 30 may be sent to combustor 108 to compensate for the shortage of fuel. The operating pressure of the fuel cell 100 is controlled by a controller (not shown) that controls the entire system based on the signal of the pressure sensor 140.

Next, a method for stopping the conventional fuel cell system will be described. In order to purge the primary side of the hydrogen separation membrane 106 with nitrogen, supply of methanol and water to the evaporator 109 is stopped, and the valve 300 is opened to supply nitrogen supplied by a nitrogen supply device provided outside to the system. Introduced to
Purging is performed in the order of the steam generation side of the evaporator 109, the reformer 101, the primary side (I) of the hydrogen separation membrane 106 in the hydrogen separator 105, the combustor 108, and the heat source side of the evaporator 109 to remove hydrogen and methanol. Replace with active gas.

In order to purge the secondary side (II) of the hydrogen separation membrane 106 in the hydrogen separator 105 with nitrogen, the valve 301 is closed, the valve 303 is opened for exhaustion, and the valve 302 is opened. The nitrogen supplied by the supplied nitrogen supply device is introduced into the hydrogen circulation system HLP, and the pump 112, the secondary side (II) of the hydrogen separation membrane 106, the humidifier 11
1. Purging the fuel electrode of the fuel cell 100 and the condenser 112 in this order, and replacing hydrogen with an inert gas.

[0008]

However, such a conventional fuel cell system has the following technical problems. In a fuel cell system employing a hydrogen separator, an alloy film mainly composed of palladium is used as the hydrogen separation film. Therefore, when the system is stopped, the temperature of the hydrogen separation film is, for example, 170 to 200 ° C., which causes hydrogen embrittlement. It is necessary to quickly remove hydrogen to a very low concentration (several hundred ppm or less) before the temperature becomes lower than the temperature.

This removal of hydrogen can be easily performed technically in an on-site fuel cell power plant by purging with nitrogen gas which is an inert gas. However, in this case, since the consumption amount of the nitrogen gas is large, the cost of the nitrogen gas to be consumed, maintenance work cost such as replacement of the nitrogen cylinder or filling of the liquid nitrogen, and the like become problems. Even a fuel cell system that does not have a hydrogen separation membrane has the same problem if a fuel cell that requires inert gas purging is used.

Therefore, various proposals have been made to save the amount of nitrogen consumed or to reduce maintenance work. For example, in the former, there is a technique described in JP-A-9-45351, and in the latter, JP-A-6-20
There is a technique described in Japanese Patent No. 3864. However, in a mobile fuel cell system used for a fuel cell vehicle, space restrictions are extremely severe, and it is very difficult to mount a large amount of nitrogen gas in a cylinder every time the system is stopped. There is a need for a fuel cell system that does not require a nitrogen purge as described above.

In a fuel cell system having no hydrogen separation membrane, for example, as described in Japanese Patent Application Laid-Open No. Hei 8-195210, the inlet and outlet sides of the fuel electrode and the air electrode of the fuel cell are shut off by shut-off valves. It has been proposed to provide a buffer tank for pressure regulation in a closed space on the fuel electrode side.

However, in a fuel cell system having a hydrogen separation membrane, it is necessary to purge nitrogen to an extremely low hydrogen concentration in order to prevent hydrogen embrittlement of the hydrogen separation membrane. Nitrogen purging cannot be eliminated, and such proposals cannot be applied to mobile fuel cell systems.

On the other hand, it is difficult to purify the fuel electrode of the fuel cell effectively only by purging it with an inert gas due to the presence of hydrogen adsorbed on the electrode catalyst. As a method for solving this and effectively performing the purging to reduce the residual hydrogen concentration, surplus power is generated while purging with an inert gas, and the surplus power is discharged by a discharge resistor circuit. Methods for consuming hydrogen are known. However, even with this method, the residual hydrogen consumption capacity of the fuel cell decreases as the residual hydrogen concentration decreases, so that after the normal operation of the system is stopped, before the system temperature decreases to a temperature at which hydrogen embrittlement starts. It is difficult to reduce the residual hydrogen concentration to an extremely low hydrogen concentration within a short time until the above.

The present invention has been made in view of such a conventional technical problem, and has a problem that the residual hydrogen concentration in a hydrogen circulation system composed of a fuel electrode side of a fuel cell and a secondary side of a hydrogen separation membrane when the system is stopped. Is to provide a mobile fuel cell system capable of reducing the hydrogen concentration to an extremely low hydrogen concentration in a short time before the temperature of the hydrogen separation membrane becomes equal to or lower than the hydrogen embrittlement temperature.

[0015]

According to a first aspect of the present invention, there is provided a fuel cell system for a mobile object, comprising: a reformer for reforming a fuel to generate a hydrogen-rich gas; and a hydrogen-rich gas generated by the reformer. A hydrogen separator that separates hydrogen from a natural gas, a fuel cell that generates power using a gas containing hydrogen and oxygen separated by the hydrogen separator, and a battery that stores power generated by the fuel cell. A power controller that controls the power generated by the fuel cell and the power stored in the battery, a circulating pump of a hydrogen circulation system including the hydrogen separator and the fuel cell, and when the system is stopped. After performing power generation by residual hydrogen in the hydrogen circulation system while circulating steam in the hydrogen circulation system, the battery is transferred from the battery to the fuel cell while circulating steam in the hydrogen circulation system. Residual hydrogen purging means for reducing the concentration of residual hydrogen in the hydrogen circulation system by applying pressure to electrochemically transport residual hydrogen in the hydrogen circulation system from the fuel electrode side to the air electrode side of the fuel cell It is provided with.

In the mobile fuel cell system according to the first aspect of the present invention, when the system is stopped, the residual hydrogen purging means includes:
After generating power by residual hydrogen while circulating water vapor in a hydrogen circulation system composed of the fuel electrode side and the hydrogen separation membrane secondary side of the fuel cell, the battery is transferred from the battery to the fuel cell while circulating water vapor in the hydrogen circulation system. By applying a voltage and electrochemically transporting a small amount of residual hydrogen from the fuel electrode of the fuel cell to the air electrode, the concentration of residual hydrogen in the hydrogen circulation system is reduced. As a result, the residual hydrogen concentration in the hydrogen circulation system
Before the temperature of the hydrogen separation membrane becomes lower than the hydrogen embrittlement temperature, the hydrogen concentration is reduced to an extremely low hydrogen concentration in a short time.

According to a second aspect of the present invention, in the mobile fuel cell system according to the first aspect, the residual hydrogen purging means charges the battery with electric power generated by the residual hydrogen. Energy efficiency is increased by charging the battery with the generated power.

According to a third aspect of the present invention, there is provided the fuel cell system for a mobile body according to the first aspect, further comprising a discharge resistance circuit for discharging surplus electric power, wherein the residual hydrogen purging means uses the electric power generated by the residual hydrogen to the discharge resistance circuit. The residual hydrogen concentration is rapidly reduced by promptly consuming the power generated by the residual hydrogen.

According to a fourth aspect of the present invention, there is provided the fuel cell system for a mobile body according to the first aspect, further comprising a discharge resistor circuit for discharging surplus power, wherein the residual hydrogen purging means is configured to control the residual hydrogen in accordance with a state of charge of the battery. Switching between charging of the battery with the generated power by hydrogen and discharging to the discharge resistor circuit, and charging and discharging of the generated power with the residual hydrogen to the battery according to the state of charge of the battery when the system is stopped. To improve the energy efficiency and quickly reduce the residual hydrogen concentration.

According to a fifth aspect of the present invention, in the fuel cell system for a mobile body according to the first aspect, the residual hydrogen purging means applies a voltage from the battery to the fuel cell to perform electrochemical transport of hydrogen for a predetermined time. When the system is shut down, the energy loss of the battery is minimized by performing the electrochemical transport of hydrogen for a certain period of time necessary to reduce the residual hydrogen concentration to a level that does not affect the hydrogen separation membrane. suppress.

According to a sixth aspect of the present invention, in the fuel cell system for a mobile body according to the first or fifth aspect, the residual hydrogen purging means sets the residual hydrogen concentration in the hydrogen circulation system to a desired concentration based on current-voltage characteristics of the fuel cell. When it is determined that the following has been reached, the application of voltage from the battery to the fuel cell is stopped, and the electrochemical transport of hydrogen is stopped,
Minimize battery energy loss.

According to a seventh aspect of the present invention, in the fuel cell system for a mobile body according to any of the first to sixth aspects, shutoff means is provided on each of an inlet side and an outlet side of the air electrode, and the residual hydrogen purging means is provided with a hydrogen circulation system. After reducing the residual hydrogen concentration of
The air electrode of the fuel cell is purged with water vapor, and thereafter the inlet and outlet sides of the air electrode are shut off by the shut-off means.

In the fuel cell system for a mobile body according to the present invention, when the system is stopped, the residual hydrogen purging means terminates the surplus power generation by the surplus hydrogen in the hydrogen circulation system, or electrochemically converts hydrogen by the fuel cell. After the transportation is completed, the air electrode of the fuel cell is purged with water vapor, and the inlet and outlet sides of the air electrode of the fuel cell are shut off by shut-off means. As a result, the hydrogen circulation system, which is a closed space on the fuel electrode side of the fuel cell, and the air electrode side of the fuel cell are both held as a closed space filled with water vapor, and the temperature of the system decreases, and water vapor is generated. When condensed, the fuel electrode side and the air electrode side of the fuel cell are set to the same reduced pressure state to suppress generation of a differential pressure on the ion conductive membrane of the fuel cell.

According to an eighth aspect of the present invention, in the fuel cell system for a mobile body according to the first aspect, a shutoff means for shutting off an inlet side and an outlet side of the hydrogen separator, and a fuel electrode side of the fuel cell is opened to the atmosphere. Opening means, and after the residual hydrogen purging means completes the electrochemical transport of the residual hydrogen in the hydrogen circulation system, shuts off the inlet side and the outlet side of the hydrogen separator in the hydrogen circulation system by the shut-off means. The fuel electrode of the fuel cell is opened to the atmosphere by the air opening means.

In the fuel cell system for a mobile body according to the present invention, when the system is stopped, the residual hydrogen purging means terminates the electrochemical transport of the residual hydrogen in the hydrogen circulation system, and then the hydrogen separator in the hydrogen circulation system. The inlet and outlet sides of the fuel cell are shut off by shut-off means, and the fuel electrode of the fuel cell is opened to the atmosphere by the open-to-air means. As a result, even if the temperature of the system is reduced and water vapor is condensed, the pressure on the fuel electrode and the air electrode side of the fuel cell is maintained at substantially the air pressure, and the generation of a differential pressure on the ion conductive membrane of the fuel cell is suppressed. .

According to a ninth aspect of the present invention, there is provided the fuel cell system for a mobile body according to any of the first to eighth aspects, further comprising a shutoff means for shutting off an inlet side and an outlet side of the hydrogen separator on the reformed gas side, The purging means shuts off the reformed gas inlet and outlet sides of the hydrogen separator by the shutoff means when the system is stopped.

According to a tenth aspect of the present invention, in the fuel cell system for a mobile body according to the ninth aspect, the residual hydrogen purging means shuts off the inlet side and the outlet side on the reformed gas side of the hydrogen separator. The reforming gas side of the hydrogen separator is purged with steam.

In the fuel cell system for a mobile body according to the ninth and tenth aspects of the present invention, when the system is stopped, the residual hydrogen purging means shuts off the inlet side and the outlet side of the reformed gas side of the hydrogen separator. Purge the reformed gas side of the separator with steam. This eliminates the necessity of supplying nitrogen from an external nitrogen supply device and purging the hydrogen in this portion as in the related art, and achieves downsizing as a system for a moving body.

[0029]

According to the first aspect of the present invention, the residual hydrogen concentration in the hydrogen circulation system is reduced to an extremely low hydrogen concentration within a short time before the temperature of the hydrogen separation membrane becomes lower than the hydrogen embrittlement temperature. be able to.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, when the system is stopped, surplus power due to residual hydrogen is charged into the battery, so that when the system is stopped, the generated power due to residual hydrogen is stored in the battery. It can be charged and energy efficiency can be increased.

According to the third aspect of the present invention, in addition to the effect of the first aspect of the present invention, the surplus power is discharged to the discharge resistor circuit when the system is stopped, so that the power generated by the residual hydrogen is quickly consumed. The residual hydrogen concentration can be promptly reduced.

According to the fourth aspect of the present invention, in addition to the effects of the first aspect of the present invention, when the system is stopped, surplus power is charged to the battery by residual hydrogen and discharged to the discharge resistor circuit according to the state of charge of the battery. Can be switched, energy efficiency can be improved, and the residual hydrogen concentration can be rapidly reduced.

According to the fifth aspect of the present invention, in addition to the effect of the first aspect of the present invention, the hydrogen for a certain period of time required to reduce the residual hydrogen concentration to a level that does not affect the hydrogen separation membrane when the system is stopped. By performing the electrochemical transport of the battery, the energy loss of the battery can be minimized.

According to the invention of claim 6, according to claim 1 or 5,
In addition to the effects of the invention, when the system is stopped, the application of voltage from the battery to the fuel cell is stopped when it is determined from the current-voltage characteristics of the fuel cell that the residual hydrogen concentration in the hydrogen circulation system has become lower than the desired concentration. By stopping the electrochemical transport of hydrogen, the energy loss of the battery can be minimized.

According to the seventh aspect of the invention, in addition to the effects of the first to sixth aspects, when the system is stopped, the hydrogen circulation system, which is a closed space on the fuel electrode side of the fuel cell, and the air electrode side of the fuel cell are closed. Both are filled with steam and can be kept as a closed space, and when the temperature of the system decreases and the steam condenses,
The fuel electrode side and the air electrode side of the fuel cell are in the same reduced pressure state, and it is possible to suppress the generation of the differential pressure on the ion conductive membrane of the fuel cell.

According to the eighth aspect of the present invention, in addition to the effect of the first aspect, even if the temperature of the system decreases when the system is stopped and water vapor condenses, the pressure on the fuel electrode and the air electrode side of the fuel cell is reduced. Can be maintained substantially at the air pressure, and the generation of a differential pressure on the ion conductive membrane of the fuel cell can be suppressed.

According to the ninth and tenth aspects, according to the first aspect,
In addition to the effects of the inventions of (1) to (8), it is not necessary to supply nitrogen from an external nitrogen supply device to purge hydrogen in this part when the system is stopped, which makes it possible to reduce the size of the system for a mobile body.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the configuration of the first embodiment of the present invention. The mobile fuel cell system according to the first embodiment has the same basic configuration as that of the conventional example shown in FIG. Therefore, hereinafter, the same reference numerals are given to elements common to the conventional example shown in FIG.

A feature of the first embodiment is that the valves 300 to 303, which are elements of the nitrogen purge system for purging hydrogen with nitrogen gas in the conventional example, are omitted, and instead, the excess Discharge resistor circuit 400 for discharging and consuming generated power, power regulator 4
02 and the provision of shut-off valves 410 and 411 for shutting off the inlet and outlet of the hydrogen separator 105 on the reformed gas side.

The power regulator 402 includes a power generated by the fuel cell 100, charging and discharging of the battery 401, a running power or a regenerative power of a running motor of the moving body, and a discharge resistance circuit 4.
The power distribution such as the discharge of surplus power to 00 is optimally controlled.

Next, the operation of the mobile fuel cell system having the above configuration when the system is stopped will be described with reference to the block diagram of FIG. 1 and the sequence diagram of FIG. On the primary side (I) of the hydrogen separation membrane 106, when the system stops (step S0), the supply of methanol to the evaporator 109 stops. Then, the water vapor causes the hydrogen separation membrane 10 in the evaporator 109, the reformer 101, and the hydrogen separator 105.
The primary side (I) of No. 6 is sequentially purged with water vapor to expel hydrogen and methanol (step S11).

When the purge with water vapor is sufficient, the supply of water to the evaporator 109 is stopped to stop the water vapor purge (step S12).
Shut-off valves 410, 4 provided at the inlet and outlet of 5
11 is shut off, and the primary side (I) of the hydrogen separation membrane 106 is confined while being replaced with water vapor (step S13).

In parallel with this, in the secondary side (II) of the hydrogen separation membrane 106, that is, in the hydrogen circulation system HLP, an inert gas purge is performed as follows. While operating the hydrogen circulation system HLP on the secondary side of the hydrogen separation membrane 106, surplus power is generated by the fuel cell 100 using excess hydrogen in the hydrogen circulation system. The power adjuster 402 outputs the surplus power to the battery 401 under the condition that the surplus power can charge the battery 401 and the battery 401 is not overcharged.
When the battery 401 is fully charged, or under conditions where the surplus power is not at a voltage that allows charging, the surplus power is discharged to the discharge resistance circuit 400 (step S2).
1).

The residual hydrogen in the hydrogen circulating system HLP gradually decreases.
When the voltage of the battery 401 is applied so as to electrochemically transport hydrogen from the fuel electrode side of the fuel cell 100 to the air electrode side, the hydrogen concentration is immediately reduced to an extremely low hydrogen concentration (step S22). The technique of electrochemical pumping is described, for example, in US Pat.
1,080, and as an improvement thereof,
The technology described in Japanese Patent Publication No. 2850 is adopted. The principle of this technology is that a voltage is applied from the battery 401 to the electrolyte membrane, hydrogen ions generated in the fuel electrode by excess hydrogen are moved to the air electrode side through the electrolyte membrane, and oxygen is generated on the air electrode side with the intervention of a catalyst. It is made to react and consume.

Thus, the primary side (I) of the hydrogen separation membrane 106
Also, after the hydrogen concentration on the secondary side (II) is sufficiently reduced, the circulation pump 112 is stopped, and all elements of the system are stopped. As a result, the temperature of the hydrogen separation membrane 106 is lowered to the hydrogen embrittlement temperature or lower. At this time, one of the hydrogen separation membranes 106
Both the secondary side and the secondary side are closed spaces in which water vapor is confined. Therefore, when the temperature decreases and the water vapor condenses, the pressure is reduced in the same manner, and the generation of the differential pressure is suppressed. 106 is prevented from being damaged.

The degree of reduction of the residual hydrogen concentration in the hydrogen circulating system HLP is determined by the current-voltage characteristics of the fuel cell 100 when surplus power is being generated and by electrochemically transporting hydrogen. Can be estimated from the current-voltage characteristics of the electrochemical hydrogen pump. Therefore, in the above-described embodiment, the above operation is performed for a predetermined period of time. However, the current-voltage characteristic corresponding to the hydrogen concentration is experimentally determined, and the data is converted into a look-up data table to the controller. A mechanism may be adopted in which the actual current-voltage characteristics are measured, the corresponding hydrogen concentration is estimated with reference to this data table, and the system is finally stopped when the hydrogen concentration falls below a predetermined value.

As described above, in the fuel cell system for a mobile unit according to the first embodiment, a conventional inert gas in which an inert gas such as nitrogen is supplied to replace a gas such as hydrogen with an inert gas is used. The same effect can be obtained by employing a method of consuming hydrogen while circulating water vapor on the secondary side of the hydrogen separation membrane and selectively transporting it electrochemically with respect to the gas purge. Therefore, there is no need to mount a cylinder filled with a large amount of inert gas on the moving body as in the related art, and maintenance such as replacement of the inert gas cylinder is not required.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment,
In addition to the configuration of the first embodiment shown in FIG. 1, shutoff valves 500 and 50 are provided at the inlet and outlet of the air electrode of the fuel cell 100.
1 is provided. Other configurations are the same as those of the first embodiment shown in FIG.

In the mobile fuel cell system according to the second embodiment, when the system is stopped, after the surplus power generation by the surplus hydrogen of the hydrogen circulating system HLP is completed or by the fuel cell 100 according to the sequence shown in FIG. After the electrochemical transport of hydrogen is completed, the compressor 120 is stopped, the air electrode of the fuel cell 100 is purged with steam using the humidifier 122, and the shut-off valves 500 and 501 are closed to close the air electrode of the fuel cell 100. Trap water vapor in the air.

When the system is stopped in this manner, the hydrogen circulation system HLP, which is a closed space on the fuel electrode side of the fuel cell 100, and the air electrode side of the fuel cell 100 are both filled with water vapor and held as a closed space. Therefore, when the temperature of the system decreases and the water vapor condenses, the fuel electrode 100 and the air electrode side of the fuel cell 100 are in the same pressure reduction state, and the generation of the differential pressure on the ion conductive membrane of the fuel cell 100 is suppressed. , Can be prevented from being damaged by the pressure difference.

Next, a third embodiment will be described with reference to FIG. The mobile fuel cell system according to the third embodiment has a shut-off valve 600 at the inlet and outlet of the secondary side (II) of the hydrogen separator 105 in addition to the configuration of the first embodiment shown in FIG. , 601 and an open valve 602 for connecting the hydrogen circulation system HLP of the fuel cell 100 to the air electrode. Other configurations are similar to those of the first configuration shown in FIG.
This embodiment is common to the above embodiments.

In the third embodiment, when the system is stopped, after the electrochemical transport of hydrogen by the fuel cell 100 is completed in accordance with the sequence shown in FIG.
0, 601 is closed. Then, after stopping the circulation pump 112 and stopping the system elements, the opening valve 602 is opened to connect the fuel electrode side of the fuel cell 100 to the air electrode side,
Release to atmosphere through air side piping.

As a result, even if the temperature of the system decreases and water vapor condenses, the pressure on the fuel electrode side and the air electrode side of the fuel cell 100 is maintained at the atmospheric pressure, and no differential pressure is generated.

In each of the above embodiments, each component can be changed as follows. In all the embodiments, water and methanol have been described as examples.However, the present invention is not limited to this. In addition to methanol, methane, gasoline, dimethyl ether, and other fuels capable of producing a hydrogen-rich gas by reforming can be used. It may be any liquid or gas, and may be water or a mixture of these fuels. In addition, the steam reforming has been described as an example, but a partial oxidation, an autothermal that simultaneously performs these, or a combination type that uses these depending on the situation may be used.

In all the embodiments, the shutoff valve 4 for shutting off the primary side of the hydrogen separation membrane 106 as a closed space.
10 is provided between the reformer 101 and the hydrogen separator 105, but is not limited to this, and may be provided between the evaporator 109 and the reformer 101.
133 and the evaporator 109 may be provided. When the shut-off valve 410 is provided between the fuel pumps 132 and 133 and the evaporator 109, the water or methanol liquid is supplied from the evaporator 109 to the tank 1 by rotating the pump in reverse.
It is also possible to shut off after collecting on the 30, 131 side.

In the third embodiment, the fuel electrode side of the fuel cell 100 is connected to the air electrode side by opening the release valve 602 to open to the atmosphere. However, the present invention is not limited to this. For example, a throttle may be provided at an air opening portion of the air electrode side pipe. Further, the fuel electrode side may not be connected to the air electrode side and may be directly opened to the atmosphere by the opening valve 602, or a throttle may be used in combination. Alternatively, the fuel electrode side may be connected to the air electrode side, and the air electrode side may be closed by a shutoff valve without opening to the atmosphere. Furthermore, the example in which the position of the open valve 602 for connecting the fuel electrode side to the air electrode side is provided at the fuel electrode outlet of the fuel cell 100 has been described, but is separated by the shutoff valves 600 and 601 for shutting off the hydrogen separation membrane 106. Any location of the hydrogen circulation system HLP may be used, and the air electrode side to be connected may be anywhere as long as it is spatially connected to the air electrode of the fuel cell 100.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a sequence diagram of an operation when the system is stopped according to the embodiment.

FIG. 3 is a block diagram showing a configuration according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 fuel cell 101 reformer 105 hydrogen separator 106 hydrogen separation membrane 108 combustor 109 evaporator 400 discharge resistance circuit 401 battery 402 power regulator 410 shutoff valve 411 shutoff valve 501 shutoff valve 502 shutoff valve 600 shutoff valve 601 shutoff valve 602 Release valve

Claims (10)

[Claims] A reformer configured to reform a fuel to generate a hydrogen-rich gas; a hydrogen separator configured to separate hydrogen from the hydrogen-rich gas generated by the reformer; A fuel cell that generates power using the gas containing hydrogen and oxygen, a battery that stores power generated by the fuel cell, and a power that is generated by the fuel cell and a power stored in the battery. A power controller for controlling; a circulating pump for a hydrogen circulating system including the hydrogen separator and the fuel cell; and, when the system is stopped, remaining water in the hydrogen circulating system while circulating steam in the hydrogen circulating system. After performing power generation with hydrogen, a voltage is applied from the battery to the fuel cell while circulating water vapor through the hydrogen circulation system, and residual hydrogen in the hydrogen circulation system is discharged from the fuel cell. A fuel cell system for a moving body, comprising: a residual hydrogen purging means for reducing a residual hydrogen concentration in the hydrogen circulating system by electrochemically transporting the residual hydrogen from the cathode side to the air electrode side. 2. The mobile fuel cell system according to claim 1, wherein the residual hydrogen purging unit charges the battery with electric power generated by the residual hydrogen. 3. The moving body according to claim 1, further comprising a discharge resistor circuit for discharging surplus power, wherein said residual hydrogen purging means discharges the power generated by said residual hydrogen to said discharge resistor circuit. For fuel cell system. 4. A discharge resistor circuit for discharging surplus power, wherein the residual hydrogen purging means charges the battery with the generated power by the residual hydrogen and charges the discharge resistor circuit according to a charge state of the battery. The fuel cell system for a mobile body according to claim 1, wherein the fuel cell system switches between the discharging and the discharging. 5. The fuel cell according to claim 1, wherein the residual hydrogen purging unit applies a voltage from the battery to the fuel cell to perform electrochemical transport of hydrogen for a predetermined time. system. 6. The fuel cell system according to claim 6, wherein the residual hydrogen purging means is configured to switch the battery from the fuel cell to the fuel cell when it is determined from the current-voltage characteristics of the fuel cell that the residual hydrogen concentration in the hydrogen circulation system has become lower than a desired concentration. 6. The fuel cell system for a mobile body according to claim 1, wherein the application of the voltage is stopped to stop the electrochemical transport of hydrogen. 7. A fuel cell system further comprising: shutoff means on each of an inlet side and an outlet side of the air electrode, wherein the residual hydrogen purging means reduces the residual hydrogen concentration in the hydrogen circulating system, and then causes the air electrode of the fuel cell to emit steam. 7. The fuel cell system for a mobile body according to claim 1, wherein the air electrode is purged, and then the inlet and outlet sides of the air electrode are shut off by the shut-off means. 8. A fuel cell system comprising: a shutoff unit that shuts off an inlet side and an outlet side of the hydrogen separator; and an opening unit that opens a fuel electrode side of the fuel cell to the atmosphere.
After the electrochemical transport of the residual hydrogen in the hydrogen circulation system is completed, the inlet side and the outlet side of the hydrogen separator of the hydrogen circulation system are shut off by the shut-off means, and the fuel electrode of the fuel cell is opened to the atmosphere. 2. The fuel cell system for a mobile body according to claim 1, wherein the fuel cell system is opened to the atmosphere by means. 9. A shutoff means for shutting off an inlet side and an outlet side on the reformed gas side of the hydrogen separator, wherein the residual hydrogen purging means is provided with a means for changing the hydrogen separator by the shutoff means when the system is stopped. The fuel cell system for a mobile body according to any one of claims 1 to 8, wherein the inlet side and the outlet side of the raw gas side are shut off. 10. The apparatus according to claim 1, wherein the residual hydrogen purging means purges the reformed gas side of the hydrogen separator with steam before shutting off an inlet side and an outlet side of the hydrogen separator on the reformed gas side. The fuel cell system for a mobile body according to claim 9, wherein