JP3349742B2 - Fuel cell vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell vehicle having a fuel cell for generating power by reacting hydrogen gas and oxygen gas, and being driven by electricity generated by the fuel cell.

[0002]

2. Description of the Related Art For example, U.S. Pat. No. 5,047,298 discloses a fuel cell which generates power by reacting hydrogen and oxygen. Japanese Patent Application Laid-Open No. 51-4717 discloses a fuel cell that generates power by reacting such hydrogen and oxygen, and drives a driving motor with the electric power generated by the fuel cell to drive the fuel. A battery car is disclosed.

[0003] As a fuel cell as described above, for example, a PEM fuel cell using a proton exchange membrane is known.
In such a fuel cell, an oxygen chamber and a hydrogen chamber are provided with a proton exchange membrane interposed therebetween, and humidified oxygen gas and humidified hydrogen gas are supplied to both chambers, and hydrogen ions ionized in the hydrogen chamber pass through the proton exchange membrane. Into the oxygen chamber, and reacts hydrogen and oxygen in the oxygen chamber to generate power.

[0004] Such a fuel cell is conventionally disposed horizontally in an automobile as shown in Figs. That is, the fuel cell 2 includes a humidifying unit 4 that humidifies oxygen gas and hydrogen gas.
An oxygen gas passage 20 for supplying and discharging oxygen gas to and from the oxygen chamber of each of the power generation cells. (Supply side passage 22 and discharge side passage 24), a hydrogen gas passage 30 for supplying and discharging hydrogen gas to the hydrogen chamber of each power generation cell.
(The supply-side passage 26 and the discharge-side passage 28) and the cooling water passage 36 (the supply-side passage 32 and the discharge-side passage 34) that supplies and discharges the cooling water for cooling the power generation cells, respectively. (In the horizontal direction in the figure)
The fuel cell 2 is disposed in a vehicle such that the stacking direction of each cell is horizontal (horizontal direction in the figure), and the fuel cell 2 is disposed in the automobile. Therefore, the oxygen gas passage 20, the hydrogen gas passage 30, and the cooling water passage 36 Each has a mode extending in the horizontal direction.

[0005]

In the above-described fuel cell, since hydrogen and oxygen react with each other, water is generated by the reaction. Therefore, for example, a PEM type fuel cell using a proton exchange membrane as described above is used. In such a case, the generated water adheres to the proton exchange membrane, which may hinder power generation. Further, in the case of a PEM type fuel cell using such a proton exchange membrane, it is necessary to make the hydrogen gas and the oxygen gas contain moisture in order to react the hydrogen gas and the oxygen gas. May be attached to the above-mentioned proton exchange membrane, which may hinder power generation.

Further, during operation of the fuel cell, hydrogen gas and oxygen gas flow in the fuel cell, so that the water produced by the above reaction and the moisture contained in the hydrogen gas and oxygen gas are removed from the hydrogen gas and oxygen gas. Due to the gas flow, the gas is discharged to the outside of the fuel cell to some extent through the hydrogen gas passage and the oxygen gas passage together with the flow. However, when the operation of the fuel cell is stopped, the flow of the hydrogen gas and the oxygen gas is stopped. In a state where the gas is stopped, the residual hydrogen gas and the residual oxygen gas in the fuel cell continue to react for a while, and therefore, the water generated by the reaction between the residual hydrogen gas and the residual oxygen gas or the water contained in the residual gas. The water that has been discharged cannot be discharged to the outside by the flow of hydrogen gas and oxygen gas as in the operation of the fuel cell, and they are discharged to the proton exchange membrane. Wear and, therefore may interfere with power generation by the adhering water subsequent startup.

[0007] The problem of water adhering to the proton exchange membrane is as follows.
In particular, water produced by reaction is remarkable, and in the case of the PEM fuel cell, water is generated by reacting in the oxygen chamber as described above.
In particular, it is important to solve the adhesion of water generated on the oxygen chamber side.

In view of the above circumstances, an object of the present invention is to provide a fuel cell vehicle capable of preventing a trouble caused by water generated by a reaction between hydrogen gas and oxygen gas.

[0009]

Means for Solving the Problems A fuel cell vehicle according to the present onset bright, in order to achieve the above object, the power generation by reaction between hydrogen gas and oxygen gas supplied from the hydrogen gas supply source and oxygen gas supply source And a hydrogen gas circulation path and an oxygen gas circulation path for supplying the unreacted hydrogen gas and oxygen gas discharged from the fuel cell to the fuel cell again, and provided in each gas circulation path. A fuel cell vehicle comprising a hydrogen gas circulation pump and an oxygen gas circulation pump, and driving a traveling motor with electricity generated by the fuel cell, wherein when the fuel cell stops operating, the hydrogen gas supply source and After stopping the supply of the hydrogen gas and the oxygen gas from the oxygen gas supply source, the electricity generated by the reaction between the residual hydrogen gas and the residual oxygen gas remaining in the fuel cell is generated. And characterized in that to operate the gas circulation pump on the gas side with a discharge action of the water produced by the reaction of at least the two gases among the two gas circulation pump.

In the fuel cell vehicle according to the present invention,
After stopping the supply of the hydrogen gas and the oxygen gas from the hydrogen gas supply source and the oxygen gas supply source, the electric power generated by the reaction between the residual hydrogen gas and the residual oxygen gas remaining in the fuel cell is used for the automobile. Both gas circulation ports
It can be configured as well to operate the two gas circulation pump other electrical equipment with lamp.

When the output of the fuel cell falls below a specified value or when the hydrogen gas pressure or oxygen gas pressure in the fuel cell falls below a specified value, the electric power generated by the reaction between the two residual gases is generated. The operation of the gas circulation pump which is operated in the above can be stopped.

When the output of the fuel cell falls below a specified value or when the hydrogen gas pressure or oxygen gas pressure in the fuel cell falls below a specified value, the two gas circulations are reduced.
The operation of the pump and electric components other than the two gases circulating pump may be configured as to stop.

The electrical components other than the two gas circulation pumps include lighting lamps, an indoor ventilation device, and an air purifier.

[0014]

[Function and Effect of the Invention The present onset fuel cell vehicle according to Ming, as described above, during operation of the fuel cell is stopped with electricity generated by the reaction between residual oxygen gas and residual hydrogen gas in both gas circulating pump Since the gas circulation pump (oxygen gas circulation pump in the case of the PEM fuel cell) having the action of discharging the water produced by the reaction of the two gases is operated at least, the residual gas having the action of discharging the reaction water is removed. A flow is formed, so that the water generated by the residual gas reaction can be discharged from the fuel cell by the flow of the residual gas, and a trouble due to the adhesion of the water generated by the residual gas reaction in the fuel cell, for example, a PEM fuel cell In this case, it is possible to suppress the occurrence of trouble due to the adhesion of the reaction product water to the proton exchange membrane. It is possible to prevent troubles caused by deposition.

Further, the electricity generated by the residual gas reaction
By also to create <br/> moving the electrical equipment other than those not both gas circulation pump only, it is possible to effectively utilize the surplus electric by the residual gas reaction.

Further, when the output of the fuel cell or the gas pressure in the fuel cell becomes equal to or less than a specified value, the operation of the gas circulation pump and the electric components is stopped, so that the operation can be appropriately stopped. it can.

Further, as the electrical components, lighting lamps,
By selecting an indoor ventilator or an air purifier that is necessary or effective to operate while the automobile is stopped, the use of the surplus power can be made more effective.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<Basic Configuration of Fuel Cell System> FIG. 1 is a diagram showing a basic configuration of a fuel cell system in an embodiment of a fuel cell vehicle according to the present invention, and FIG. 2 is a diagram showing a fuel cell in FIG. 3 is a diagram showing flows of hydrogen gas, oxygen gas, and cooling water as reaction gases in the fuel cell shown in FIG. 2, and FIG. 4 is a detailed sectional view showing a flow of oxygen gas in the fuel cell shown in FIG.

First, the fuel cell will be described with reference to FIGS. In the present embodiment, a PEM type fuel cell that generates power by reacting hydrogen gas and oxygen gas using a proton exchange membrane as a fuel cell is used.

As shown in FIG. 2, the fuel cell 2 includes a humidifying section 4 and a power generating section 6, and the humidifying section 4 converts oxygen gas and hydrogen gas, which are reaction gases, by cooling water using pure water. The humidifying unit 6 is configured so that the humidified oxygen gas and the hydrogen gas react with each other in the power generating unit 6 to generate power, and the power generating unit 6 that generates reaction heat by the reaction is cooled by the cooling water.

The humidifying section 4 is formed by stacking a plurality of humidifying cells, and oxygen gas, hydrogen gas and cooling water pass through each cell and are humidified in each cell. Humidification in each cell is performed by bringing oxygen gas and hydrogen gas into contact with cooling water through a polymer membrane that allows moisture to pass through, so that oxygen gas and hydrogen gas contain moisture at a saturated vapor pressure.

As shown in FIG. 4, the power generation unit 6 is formed by stacking a plurality of power generation cells 8, and the oxygen gas and the hydrogen gas humidified by the humidification unit 4 pass through each cell 8 in order, and It reacts at 8 to generate electricity. Each of the cells 8 includes a proton exchange membrane 10 through which only hydrogen ions pass, a hydrogen chamber 12 and an oxygen chamber 14 partitioned by the proton exchange membrane 10, a hydrogen-side electrode 16 and an oxygen-side electrode provided on the proton exchange membrane 10. An electrode 18 is provided.

The power generation section 6 is provided with an oxygen gas passage 20 extending in the direction in which the power generation cells 8 are stacked. The oxygen gas passage 20 includes a supply-side passage 22 and a discharge-side passage 24 extending in the stacking direction of the cells 8, and supplies oxygen gas from the supply-side passage 22 to the oxygen chamber 14 of each cell 8. Oxygen chamber 14
The unreacted oxygen gas is discharged from the discharge port through the discharge side passage 24.
The power generation unit 6 is provided with a hydrogen gas passage (not shown) configured similarly to the oxygen gas passage 20. This hydrogen gas passage also has a supply-side passage and a discharge-side passage extending in the stacking direction of the cells 8 similarly to the oxygen gas passage 20, and supplies hydrogen gas from the supply-side passage to the hydrogen chamber 12 of each cell. At the same time, unreacted hydrogen gas is discharged from the hydrogen chamber 12 of each cell via the discharge side passage. Further, a cooling water passage (not shown) is provided in the power generation unit 6, and the cooling water passage also includes a supply-side passage and a discharge-side passage extending in the stacking direction of the cells 8 similarly to the oxygen gas passage 20. The cooling water is supplied from the supply passage to the cooling water chambers 25 formed between the cells 8, and the cooling water is discharged from the cooling water chambers 25 through the discharge passages.

The power generation mechanism in each of the power generation cells 8 is as follows. That is, the humidified hydrogen supplied to the hydrogen chamber 12 of each cell 8 is ionized under the hydrogen-side electrode 16, and the hydrogen ions enter the oxygen chamber 14 through the proton exchange membrane, and the oxygen-side electrode 18 Under this condition, hydrogen and oxygen react with each other to generate electric power and generate water, and the generated water is discharged from the oxygen-discharge-side path 24 together with the unreacted oxygen gas by the flow of the unreacted oxygen gas.

FIG. 3 shows passages and flows of oxygen gas, hydrogen gas and cooling water in the humidifying section 4 and the power generation section 6. As shown in the drawing, the hydrogen gas passage 30 including the supply-side passage 26 and the discharge-side passage 28, the cooling water passage 36 including the supply-side passage 32 and the discharge-side passage 34, and the oxygen gas passage
Similarly to 20, the cells 8 extend in the stacking direction of the cells 8. In addition, the fuel cell 2 is disposed with the stacking direction of the cells 8 being vertically arranged, the humidifying unit 4 is located above the power generating unit 6, and the oxygen gas passage 20, the hydrogen gas passage 30, and the cooling water passage 36 are all provided. The cooling water is supplied from below and discharged upward, while the oxygen gas and hydrogen gas are supplied from above and discharged downward.

As described above, the fuel cell 2 is vertically disposed so that the extending direction of the hydrogen gas passage 30 and the oxygen gas passage 20 passing through the power generation unit 6 is vertical. By supplying hydrogen gas and oxygen gas from the respective upper portions to the gas passages 20 and discharging unreacted hydrogen gas and oxygen gas from the lower portions,
The hydrogen gas and the oxygen gas flow downward in the hydrogen gas passage 30 and the oxygen gas passage 20 extending in the vertical direction. Therefore, gravity acts on the water discharged by the flow of the hydrogen gas and the oxygen gas in the discharge direction, and the gravity promotes the discharge of the water, and the water generated in the reaction product water, the hydrogen gas, and the oxygen gas. It is possible to suppress the occurrence of trouble due to water adhesion in the fuel cell, for example, the trouble due to water adhesion to the proton exchange membrane in the case of a PEM type fuel cell.

Next, a fuel cell system in an automobile using the above-described fuel cell will be described with reference to FIG. The illustrated fuel cell system includes two fuel cells 2. Oxygen gas, hydrogen gas, and cooling water are supplied to both fuel cells 2 in parallel, and electricity generated by each fuel cell 2 is taken out in series. It is.

Each fuel cell 2 is supplied with oxygen gas itself from a high-pressure oxygen cylinder 50 as an oxygen gas supply source via an oxygen gas supply path 52. Further, unreacted oxygen gas is discharged from each fuel cell 2 through an oxygen gas discharge path 54. The oxygen gas discharge path 54 is connected to the oxygen gas supply path 52 at a point A.
The oxygen gas circulation path 56 is formed by the oxygen gas passage in each fuel cell 2, the oxygen gas discharge path 54, and the portion of the oxygen gas supply path 52 from the point A to the fuel cell 2; The unreacted oxygen gas is circulated through the oxygen gas circulation path 56.

In the oxygen gas supply path 52, a solenoid valve SV as an original valve is sequentially provided from the oxygen gas supply source 50 side.
1 ', pressure regulator P to keep supply oxygen gas pressure constant
R ', a solenoid valve SV3' provided on the branch path,
A pressure sensor PS1 ', a solenoid valve SV2' serving as an inlet valve are provided, and a flow rate sensor FS ', a solenoid valve SV4' serving as a circuit opening / closing valve, and a pressure sensor PS2 'are provided in a portion serving also as the oxygen gas circulation path 56. ing. In the oxygen gas discharge passage 54, a solenoid valve SV5 'which is a purge valve provided in a branch passage, a water trap container (water separator) 58, an oxygen gas circulation pump G
P 'and a deionization filter DIF' are provided.

Each fuel cell 2 is supplied with hydrogen gas itself via a hydrogen gas supply path 62 from a hydrogen storage alloy 60 storing hydrogen as a hydrogen gas supply source. Further, unreacted hydrogen gas is discharged from each fuel cell 2 through a hydrogen gas discharge path 64, and the hydrogen gas discharge path 64 is connected to the hydrogen gas supply path 62 at a point B, and the inside of each fuel cell 2 Hydrogen gas passage, hydrogen gas discharge path 64, and hydrogen gas supply path
A hydrogen gas circulation path 66 is formed by the portion from 62 to the fuel cell 2 out of the point B, and the unreacted hydrogen gas is circulated through the hydrogen gas circulation path 66.

In the hydrogen gas supply path 62, a solenoid valve SV as a source valve is sequentially provided from the hydrogen gas supply source 60 side.
1. Pressure regulator P that keeps the supply hydrogen gas pressure constant
R, a solenoid valve SV3 provided on a branch path, a pressure sensor PS1, a solenoid valve SV serving as an inlet valve
2 is provided, and a flow rate sensor FS, a solenoid valve SV4 as a circulation path opening / closing valve, and a pressure sensor PS2 are provided in a portion serving also as the hydrogen gas circulation path 66. The hydrogen gas discharge path 64 is provided with a solenoid valve SV5, which is a purge valve provided in a branch path, a water trap container (water separator) 68, a hydrogen gas circulation pump GP, and a deionization filter DIF. A branch path is provided between the hydrogen gas supply source 60 and the solenoid valve SV1, and a leak valve RV, a manual valve MV1, and a quick connector QC are provided.
When hydrogen is stored in the quick connector QC, a hydrogen cylinder (not shown) is connected to the quick connector QC.

Each fuel cell 2 is provided with a cooling water circulation path 70. The cooling water circulation path 70 includes the above-described cooling water passage (not shown) in the fuel cell 2, and the cooling water circulation path 70 includes the above-described water trap container 58, the cooling water circulation pump W
P, a three-way valve TV, a radiator RD for radiating cooling water, a bypass BP and a deionizing filter DIF provided in parallel with the radiator RD, and a conductivity sensor CS for detecting the conductivity of the cooling water.

Each of the fuel cells 2 is provided with a voltage sensor VS for detecting an output voltage of each of the power generation cells 8 of the power generation unit 6, and a power supply switch is connected to an electric wire connecting the two fuel cells 2 in series. A running motor 72 is connected via SW1, and various electric components (including the above-mentioned gas circulation pumps GP and GP ') are connected via a power supply switch (not shown).

In the above system, the solenoid valves SV6, SV6 'and SV
7. Manual valves MV2, MV2 ', MV3' and an automatic valve AV1 are provided.

In the system configured as described above, when the normal operation of the fuel cell is stopped, all the solenoid valves other than the solenoid valves SV4 and SV4 ', the manual valve, the auto valve, and the leak valve are closed, and each of the valves is closed. The driving of the circulation pumps GP and GP'WP is stopped, and the switch SW1 of the traveling motor 72 and the switches of various electric components are open.

During normal fuel cell operation (during operation), the solenoid valves SV1, SV2, SV1 ', SV
2 ′, and a hydrogen gas and oxygen gas circulation pump G
P and GP 'are operated to supply oxygen gas and hydrogen gas to each fuel cell 2 and circulate them (from the oxygen gas and hydrogen gas supply sources 50 and 60, oxygen gas and hydrogen gas are newly added by the amount consumed by the reaction). Hydrogen gas is supplied),
In addition, the cooling water circulation pump WP is operated to circulate the cooling water to the fuel cell 2, whereby the power generation in each fuel cell 2 and the cooling of each fuel cell 2 are performed by the above-described mechanism.
Further, the switch SW1 is closed to drive the traveling motor 72 with the generated electricity, and the above-mentioned switch (not shown) is closed to supply electric power to various electric components.

<Operation Stop Procedure of Fuel Cell System> Next, the operation stop procedure of the fuel cell system will be described with reference to FIG. This operation stop is performed in a procedure that can effectively remove water generated by the reaction of the residual gas in the fuel cell 2 and effectively use the surplus electric power by the reaction of the residual gas.

First, at P1, the power supply switch from the fuel cell to the external load, that is, the power supply switch SW1 to the traveling motor 72 and the above-mentioned power supply switch to the various electric components are turned off. SV1 '
Is closed, the supply of hydrogen gas and oxygen gas from the hydrogen gas supply source 60 and the oxygen gas supply source 50 to the fuel cell 2 is stopped.

However, even when the supply of the hydrogen gas and the oxygen gas is stopped in this way, the hydrogen gas and the oxygen gas remain in the fuel cell 2, and the residual gas remains in the fuel cell 2 thereafter. Since the reaction continues, the water generated by the reaction adheres to the proton exchange membrane 10, which prevents the reaction gas from reaching the proton exchange membrane at the time of restart.

Therefore, after the valves SV1 and SV1 'are closed, at P3, the hydrogen gas circulation pump GP and the oxygen gas circulation pump GP utilize the electric power generated by the reaction of the residual gas in the fuel cell 2. 'Is activated. This operation is performed by closing the power supply switches for the two gas circulation pumps GP and GP '. As a result, even during the reaction of the residual gas, the hydrogen gas and the oxygen gas circulate in the hydrogen gas circulation path 66 and the oxygen gas circulation path 56. The hydrogen gas and the oxygen gas are satisfactorily discharged to the outside by the flow of the gas, and the adhesion of water to the proton exchange membrane after the fuel cell operation is stopped can be prevented.

In P4, the gas circulation pumps GP, GP 'are operated using the surplus power generated by the reaction of the residual gas together with the operation of the gas circulation pumps GP, GP'.
Activate predetermined electrical components other than GP '. This operation is performed by closing a power supply switch for the predetermined electrical component. In operating this electrical component, it is necessary to operate the vehicle while the vehicle is stopped or it is desirable to activate an effective electrical component.
For example, lighting lamps such as foot lamps and hazard lamps,
The vehicle interior ventilation device or the air purifier can be suitably operated. In the operation of the vehicle interior ventilation device, the vehicle interior temperature can be activated when the vehicle interior temperature is higher than the outside air temperature and the vehicle interior temperature is higher than the set temperature, for example, for the purpose of preventing the vehicle interior temperature from rising in summer.

Subsequently, when it is detected at P5 that the output power or the residual gas pressure of the fuel cell 2 has become equal to or lower than a predetermined value, it is considered that the amount of the residual reactant gas has been sufficiently reduced, and P
At 6, the driving of the gas circulation pumps GP and GP ′ is stopped, and at the same time, the driving of the electrical components is stopped.
2. Close SV2 'to stop the fuel cell system.
The output voltage of the fuel cell 2 is the voltage (1
(The sum of the power generation voltages of a plurality of power generation cells constituting one fuel cell) or the voltage of each power generation cell. These voltages are detected by the voltage sensor VS provided on the fuel cell 2 described above. The residual gas pressure may be either the residual hydrogen gas pressure, the residual oxygen gas pressure, or both of them, and the residual gas pressures can be detected by the pressure sensors PS2 and PS2 '. .

As described above, after the operation of the fuel cell is stopped, that is, after the supply of the reaction gas to the fuel cell is stopped, the two gas circulation pumps GP and G are used by using the electricity generated by the reaction of the residual gas.
Since P 'is driven, the water generated by the reaction of the residual gas and the water containing the residual gas can be satisfactorily discharged from the fuel cell 2 by the flow of the residual gas. It is possible to prevent troubles at the time of starting due to the above-mentioned factors.

In addition to the excess power generated by the residual gas reaction, the excess power has been leaked in the past. Since it is configured to be driven, it is possible to effectively use the surplus power.

<Start-up procedure of fuel cell system> Next, the start-up procedure of the fuel cell system will be described with reference to FIG.
This will be described with reference to FIGS. When starting the fuel cell system, in addition to the check for water adhering to the fuel cell, a supply gas pressure check, a gas leak check, and a leak check are automatically performed. The operation shifts to operation, and if there is any inconvenience, the activation is stopped. This makes it possible to automatically perform the above-mentioned checks that are difficult for a normal user who does not have specialized knowledge, and to automatically start the vehicle if there is any inconvenience, thereby achieving safe driving.

As shown in FIG. 6, when starting up the fuel cell system, a start switch (not shown) for supplying power from a normal battery (not shown) to the fuel cell system control circuit at Q1 (both gas circulation pumps) GP, G
(Except for the power supply switch to P ′). Subsequently, the valves SV1 and SV1 'are opened in Q2, and the supply gas pressure is checked by the pressure sensors PS1 and PS1'. If the supply gas pressure is abnormal, stop the operation.
In step 4, the valves SV2 and SV2 'are opened to supply oxygen gas and hydrogen gas to the fuel cell 2. In Q5, the gas leak in the fuel cell 2 is checked. If there is gas leak, the start is stopped. If there is no gas leak, the leak check is performed in Q6.
If there is a short circuit, stop the startup.
The current and temperature are detected, and the gas circulation pumps GP and G are
The power supply switch to P 'is closed, the two gas circulation pumps GP and GP' are operated, and the generated voltage is checked in Q9. If the voltage is abnormal, the start is stopped. Since the operation is normal, the operation is continued as it is, and the operation shifts to the normal operation of turning on the power supply switch SW1 to the traveling motor 72.

Next, each of the above checks will be described in detail. First, the supply gas pressure check is performed according to the procedure shown in FIG. FIG. 7 shows a procedure for checking the supply hydrogen gas pressure.
The supplied oxygen gas pressure check is performed in the same manner. First, the valve SV1 is opened at R1. At this time, the valve SV2
Is still closed. Therefore, hydrogen gas is supplied from the hydrogen gas supply source 50 up to the valve SV2, and the pressure downstream of the pressure regulator PR is adjusted to a predetermined gas pressure by the pressure regulator PR. Therefore, in this state, the supply gas pressure is checked by detecting the pressure with the pressure sensor PS1 provided between the pressure regulator PR and the valve SV2 (this gas pressure check is eventually performed by the pressure regulator PR
Is performed, and when the detected gas pressure is equal to or less than a specified value (determined based on the gas pressure to be adjusted by the pressure regulator PR) at R2, the supply gas pressure is normal, and the process proceeds to R9. Open SV2 and proceed to the next process (Q5 in FIG. 6). If the detected gas pressure is higher than the specified value and the gas pressure is abnormal, the process proceeds to R3, where the valve SV1 is closed, the valve SV3 is opened at R4 to release hydrogen gas into the atmosphere, and the pressure sensor PS1 detects the gas pressure at R5. Is detected, and it is determined whether the detected gas pressure has decreased to a specified value or less.
When the value falls below the specified value, the SV3 is closed at R6, and it is determined at R7 whether the number of executions of R1 to R6 has reached the specified number. If not, the process returns to R1 and returns to R1 to R6 again.
Perform steps up to. Then, the steps from R1 to R6 are repeated, and if the detected gas pressure of the pressure sensor PS1 becomes less than or equal to the specified value in R2 during the process, R9 is performed.
If the number of executions of the steps R1 to R6 reaches the specified number without the detected gas pressure of the pressure sensor PS1 falling below the specified value on the way, the supply hydrogen gas pressure is abnormal (the pressure regulator PR is abnormal). Then, the process proceeds to R8, and the activation process is stopped there. It should be noted that repeating the above R1 to R6 a specified number of times means that checking the supply hydrogen gas pressure is repeated a specified number of times.

FIG. 8 is a diagram showing another supply gas pressure check procedure. While the check procedure shown in FIG. 7 is to open the valve SV3 and release hydrogen gas to the atmosphere when the gas pressure check is repeated, the procedure shown in FIG. The hydrogen gas is discharged into the battery system, and is released to the atmosphere only when the abnormality is still abnormal, and the check is repeatedly performed. This is intended to reduce the discharge of hydrogen gas to the atmosphere.

In this procedure, at S1, the valve SV1
Is opened, and it is determined in S2 whether the detected gas pressure of the pressure sensor PS1 is equal to or lower than a specified value. If the detected gas pressure is equal to or lower than the specified value, the valve SV2 is opened in S13.
Close 1. The procedure so far is the same as the procedure described above. Then, after closing the valve SV1, in this procedure, the valve SV2 is opened in S4, whereby hydrogen gas is supplied to the fuel cell 2.
Then, in S5, it is determined whether or not the detected gas pressure of the pressure sensor PS1 has fallen below a specified value. Since the gas pressure immediately after opening the valve SV2 has not yet fallen below the specified value, the process proceeds from S5 to S6, where it waits for a specified time after opening the valve SV2. To close the valve SV2, and repeat the steps S1 to S4 again. When the detected pressure becomes equal to or less than the specified value in S2 while the steps S1 to S4 are being repeated, the process proceeds to S13. If the steps S1 to S4 are repeated without the detected gas pressure becoming equal to or lower than the specified value in S2, the hydrogen gas circulation pump GP has not been operated yet, so that hydrogen gas cannot be released into the fuel cell 2 during that time. After the valve SV2 is opened, the pressure does not fall below the specified value even when the specified time has elapsed. Then, the process proceeds from S6 to S7, where the valve SV3 is opened,
In S8, the process waits until the detected gas pressure of the pressure sensor PS1 becomes equal to or less than the specified value.
Is closed, and in S10, it is determined whether or not the number of executions of steps S1 to S9 has reached a specified number. If not, the valve SV2 is closed in S12, the process returns to S1, and S1 to S9 are repeated again. If the detected gas pressure becomes equal to or less than the specified value in S2, the process proceeds to S13, and if the number of repetitions of S1 to S9 reaches the specified number without decreasing the detected gas pressure in S2, the startup process is stopped in S11. .

Next, the gas leak check shown at Q5 in FIG. 6 will be described. As described above, when the supply gas pressure check determines that the gas pressure is normal, the valves SV2 and SV2 '
Open and check for gas leakage. This gas leak check is performed by the aforementioned flow sensors FS and FS '. That is, immediately after opening the valves SV2 and SV2 ', the hydrogen gas and the oxygen gas flow toward the inside of the fuel cell 2,
At this time, the gas circulation pumps GP and GP 'have not been operated yet, so that when hydrogen gas and oxygen gas flow to some extent, the pressures of the hydrogen gas and oxygen gas in the fuel cell 2 rise and the pressure regulators PR and PR' , And almost no more flows toward the fuel cell 2 thereafter. However, at this time, if gas leakage occurs due to damage or the like in the fuel cell 2, hydrogen gas and oxygen gas continue to flow toward the fuel cell 2 by a predetermined amount.

Therefore, the gas flow rate is detected by the flow rate sensors FS, FS 'provided between the valve SV2 and the fuel cell 2, and the detected flow rate after a lapse of a specified time from the time when the valves SV2, SV2' are opened is defined. If the value is greater than or equal to the specified value, it is determined that there is no gas leak.If the value is less than the specified value, it is determined that there is no gas leak.If there is a gas leak of either hydrogen gas or oxygen gas, the startup process is stopped. At this time, the process proceeds to the next earth leakage check.

Next, a description will be given of the earth leakage check indicated by Q6 in FIG. The leakage check checks whether or not leakage occurs through the cooling water. In the leakage check, the electric conductivity of the cooling water is detected by the above-described conductivity sensor CS. When the voltage is smaller than the specified value, the start is stopped because there is a risk of leakage through the power supply, and the next voltage check is performed because there is no risk of leakage.

Next, the voltage check indicated by Q9 in FIG. 6 will be described. As described above, at the time of start-up, water generated by the reaction of the residual gas at the time of operation stop may adhere to the proton exchange membrane, which may hinder normal reaction power generation. Therefore, it is checked whether or not the fuel cell 2 is generating power normally at the time of starting. If the normal power generation is not performed, the starting is stopped. As a cause of the failure of normal power generation, other than the adhesion of water to the proton exchange membrane, various failures of the fuel cell itself such as fuel cell damage, proton exchange membrane and electrode deterioration may be considered. The voltage check can detect not only a trouble due to water adhesion but also such a failure of the fuel cell itself, and the startup can be stopped accordingly.

The procedure of this voltage check will be described with reference to FIG. First, at T1, the gas circulation pumps GP, G
Activate P '(see Q8 in FIG. 6). Next, a voltage check is performed at T2. In this voltage check, the voltage sensor VS detects the voltage of each power generation cell 2 of the fuel cell 2 or each of a plurality of power generation cell groups including a plurality of power generation cells 8, and any of those voltages is set to a specified value (originally). It is determined that the voltage is normal if it is equal to or more than the specified value (determined based on the voltage that would normally be generated), and it is determined that the voltage is abnormal if any of them is smaller than the specified value. If the voltage is abnormal, that is, if either does not reach the specified value, wait until the specified time elapses at T3 (because a predetermined time may be required for the rise of the voltage), and all the voltages are specified before the specified time elapses. When it is determined that the voltage is equal to or more than the value and the voltage is normal, the process proceeds to T5 to end the start-up process, and thereafter, the operation of the fuel cell is continued to shift to the normal operation. If any of the voltages does not reach the specified value even after the lapse of the predetermined time, it is determined that the voltage is abnormal, the process proceeds to T4, and the startup process is stopped.

FIG. 10 is a diagram showing another voltage check procedure. In the above-described procedure, the gas circulation pumps GP and GP 'are operated to wait for a specified time, and if the voltage still does not reach the specified value, the start is stopped. If a certain amount of adhered water is removed by the gas flow, but the adhered water still remains, the operation is stopped as it is, but the adhered water is basically removable and, therefore, such adhered water is removed. Starting and stopping only when the voltage is abnormal even after the removal can reduce the start and stop due to adhesion water, and start and stop only when the voltage is abnormal due to adhesion water that cannot be completely removed. It is convenient.

FIG. 6 is a diagram showing a voltage check procedure incorporating the removal of attached water. As shown in the figure, first, the gas circulation pumps GP and GP 'are operated at U1, a voltage check similar to that at T2 is performed at U2, and the process waits until the specified time elapses at U3, and if the generated voltage is determined to be normal before the specified time elapses. Proceed to U8 to end the startup process. Up to this point in Figure 9
Are the same as T1, T2, T3, and T5 in the procedure shown in FIG.

Next, when the power generation voltage does not become normal after the lapse of the specified time, a water droplet removal process (adhered water removal control) is executed at U4. This water droplet removal process can be performed by, for example, increasing the gas flow rate or increasing or decreasing the gas flow rate. The increase in the gas flow rate is caused by the purge valves SV5 'and SV5 on the oxygen gas and hydrogen gas circulation paths 56 and 66.
, The oxygen gas and the hydrogen gas in the fuel cell 2 are exhausted at once, thereby instantaneously increasing the gas flow rate or the oxygen gas circulation pump G.
It can be performed by a method of increasing the flow rate of P ′ and the hydrogen gas circulation pump GP. The increase / decrease change of the gas flow rate can be performed, for example, by repeatedly turning on / off the oxygen gas circulation pump GP ′ and the hydrogen gas circulation pump GP.
Alternatively, it can be executed by repeatedly opening and closing the above-described circulation path opening / closing valves SV4 'and SV4 provided on the oxygen gas and hydrogen gas circulation paths 56 and 66.

A voltage check similar to that of T5 is performed at U5 while the above-described water droplet removal process is being performed. If the voltage becomes normal, the water droplet removal process is terminated, the process proceeds to U8, and the startup process is terminated. If the voltage is not determined to be normal in U5, it is determined in U6 whether or not the water droplet removal process has been performed a specified number of times or for a specified time. Only when this occurs, the activation process is stopped at U7.

In the embodiment shown in FIGS. 9 and 10, the normality of the power generation voltage is determined based on whether the power generation voltage of each power generation cell or the power generation voltage of each power generation cell group is equal to or higher than a specified value. The variation of the power generation voltage in each power generation cell (for example, the difference between the maximum value and the minimum value) or the power generation voltage between each power generation cell group (the power generation voltage of the power generation cell group is the sum of the power generation voltages of the power generation cells in the power generation cell group) )
It is possible to judge whether the variation of the fuel cell is equal to or more than a specified value (abnormal voltage) or smaller than the specified value (normal voltage), and the power generation voltage of each fuel cell itself (sum of the power generation voltages of the power generation cells in the fuel cell) Can be determined based on whether or not is greater than a specified value (normal voltage) and smaller than a specified value (abnormal voltage).

As described above, the cause of the abnormality in the generated voltage may be not only the adhering water but also the failure of the fuel cell. According to the procedure shown in FIG. 9, it is possible to determine the cause of the abnormality in the generated voltage. In spite of the fact that it is basically possible to remove the adhered water and it is desirable to start after removing the adhered water, the start-up is also uniformly stopped in the case of such adhered water. However, according to the procedure shown in FIG. 10, most of the startup and shutdown based on the voltage abnormality due to such adhering water can be avoided, and basically, the voltage due to the failure of the fuel cell itself which cannot be immediately solved on the spot. This is convenient because it can be started and stopped only when an abnormality occurs.

Further, in the above embodiment, the hydrogen gas side and the oxygen gas side are configured in the same manner with respect to the removal of the adhering water. However, the problem of the adhering water is particularly large in the weight of the reaction product water generated in the oxygen chamber. The operation of the gas circulation pump using the surplus electric power and the control of removing adhering water by increasing or decreasing the gas flow rate can be performed only on the oxygen gas side.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a fuel cell system in a fuel cell vehicle according to the present invention.

FIG. 2 is a diagram showing a fuel cell in FIG. 1;

FIG. 3 is a diagram showing flows of hydrogen gas, oxygen gas and cooling water in the fuel cell in FIG.

FIG. 4 is a cross-sectional view showing a configuration of a power generation unit of the fuel cell in FIG. 2 and a flow of oxygen gas.

FIG. 5 is a flowchart showing an example of a procedure for stopping operation of the fuel cell system.

FIG. 6 is a flowchart illustrating an example of a startup procedure of the fuel cell system.

7 and 8 are flowcharts each showing an example of a supply gas pressure check procedure.

9 and 10 are flowcharts each showing an example of a generation voltage check procedure.

FIG. 11 and FIG. 12 are views showing an arrangement of a conventional fuel cell.

[Explanation of symbols]

 2 Fuel cell 6 Power generation unit 8 Power generation cell 20 Oxygen gas passage 30 Hydrogen gas passage 50 Oxygen gas supply source 56 Oxygen gas circulation passage 60 Hydrogen gas supply source 66 Hydrogen gas circulation passage 72 Running motor GP Hydrogen gas circulation pump GP 'oxygen gas Circulation path pump VS Voltage sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-109127 (JP, A) JP-A-62-139272 (JP, A) JP-A-61-32362 (JP, A) JP-A-3-32 159073 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 8/04 H01M 8/00 B60L 11/18

Claims (5)

(57) [Claims] 1. A fuel cell for generating electric power by a reaction between a hydrogen gas supplied from a hydrogen gas supply source and an oxygen gas supply source and an oxygen gas, and the unreacted hydrogen gas and oxygen discharged from the fuel cell A hydrogen gas circulating path and an oxygen gas circulating path for supplying gas to the fuel cell again, and a hydrogen gas circulating pump and an oxygen gas circulating pump provided in the respective gas circulating paths, were used to generate power with the fuel cell. A fuel cell vehicle that drives a traveling motor by electricity, comprising: stopping the supply of hydrogen gas and oxygen gas from the hydrogen gas supply source and the oxygen gas supply source when the operation of the fuel cell is stopped; The electricity generated by the reaction between the residual hydrogen gas and the residual oxygen gas remaining in the A fuel cell vehicle, characterized in that those operating the gas circulation pump on the gas side with a discharge action. 2. After stopping the supply of hydrogen gas and oxygen gas from the hydrogen gas supply source and the oxygen gas supply source,
In electricity generated by the reaction between the residual hydrogen gas remaining in the fuel cell and the residual oxygen gas, after having mounted on a vehicle
Claims, characterized in that serial but also to operate the two gas circulation pump other electrical equipment with both gas circulating pump
1 Symbol placement of fuel cell vehicles. 3. When the output of the fuel cell falls below a specified value or when the hydrogen gas pressure or oxygen gas pressure in the fuel cell falls below a specified value, the electric power generated by the reaction between the two residual gases. in a fuel cell vehicle according to claim 1, wherein the operation of the gas circulating pump which is actuated in which stopping. 4. The two gas circulation pumps when the output of the fuel cell falls below a prescribed value or when the hydrogen gas pressure or oxygen gas pressure inside the fuel cell falls below a prescribed value.
The fuel cell vehicle in accordance with claim 2, wherein the operation of electrical equipment other than the flop and the two gases circulating pump is intended to stop. 5. An electrical component other than the two gas circulation pumps,
The fuel cell vehicle according to any one of claims 2 to 4, comprising at least one of an illumination lamp, an indoor ventilation device, and an air purifier.