JP2008097909A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generated electric power of a fuel cell from becoming less than the power required for traveling after a fuel cell vehicle starts to travel in the fuel cell system. <P>SOLUTION: In a starting process of the fuel cell, by detecting temperature of a hydrogen system exhaust valve, it is determined whether or not the hydrogen system exhaust valve is in a state capable of not exhausting a fuel gas after reaction to the atmosphere. When the state is determined that the hydrogen system exhaust valve can not exhaust the fuel gas after reaction to the atmosphere, an inverter element is made to be fully opened so that the generated power of the fuel cell is not transmitted to a vehicle driving motor, and the fuel cell vehicle is prevented from starting to travel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to control at the time of startup of the fuel cell system.

  In a fuel cell, for example, hydrogen containing hydrogen and oxygen containing oxygen are used as fuel, and electricity is generated by an electrochemical reaction and water is generated on the oxidizer electrode side. Discharged. In addition, the hydrogen gas flowing through the fuel side electrode is consumed as a part of the hydrogen flowing through the flow path reacts, so it is a circulation system in which hydrogen is circulated by the hydrogen pump and consumed in the power generation reaction. A minute amount of hydrogen is supplied from an external hydrogen gas tank to a hydrogen circulation system.

  In such a fuel cell system, air containing nitrogen that is not used in the electrochemical reaction is used as an oxidizing agent, so that nitrogen that is not used in the electrochemical reaction stays in the air flow path of the air side electrode. At the same time, it cross leaks to the hydrogen side electrode through the diffusion layer and the electrolyte membrane. In addition, a part of moisture generated in the air side electrode by the electrochemical reaction for power generation cross leaks to the hydrogen side electrode through the diffusion layer and the electrolyte membrane. Thus, nitrogen and moisture cross leak from the air side electrode to the hydrogen side electrode of the operating fuel cell.

  However, since the hydrogen system is a circulation system as described above, nitrogen and moisture entering the hydrogen system during operation are gradually accumulated in the hydrogen circulation system, and the concentration of impurities other than hydrogen increases. When the impurities in the hydrogen system increase in this way, the hydrogen partial pressure decreases and the power generation amount decreases. Therefore, the hydrogen system is equipped with a hydrogen-based discharge valve that discharges impurities such as nitrogen and moisture remaining in the hydrogen circulation system by discharging the hydrogen gas after reaction at the hydrogen side electrode out of the system. An exhaust system is installed.

  The hydrogen discharge valve of this hydrogen discharge system is opened, for example, when the fuel cell is started, and discharges the impurity gas on the hydrogen side electrode to increase the hydrogen concentration in the hydrogen side electrode and increase the power generation amount. It is also used to increase. Then, after the fuel cell is started, the hydrogen-based discharge valve is opened and closed by a predetermined sequence, for example, and operates to discharge the impurities on the hydrogen side electrode and maintain the power generation amount (see, for example, Patent Document 1). .

  As described above, moisture stays in the hydrogen system of the fuel cell. For example, when the fuel cell is stopped in a low temperature state, the water accumulated in the hydrogen discharge system may freeze and the hydrogen discharge valve may not be opened or closed. Then, since it becomes impossible to raise the hydrogen partial pressure of the hydrogen side electrode at the time of starting, there was a problem that it became impossible to maintain the generated power of the fuel cell.

  For this reason, before starting the fuel cell, if the temperature of each part is measured and it is determined that the hydrogen discharge valve of the hydrogen system is frozen and cannot be operated, the start of the fuel cell is prohibited, A method of allowing the fuel cell to start, supplying power from the fuel cell to the thawing heater of the hydrogen discharge valve in the fuel cell start process, heating and thawing the hydrogen discharge valve, and starting up to full output Has been proposed (see, for example, Patent Document 1).

JP 2004-172025 A

  If the start of the fuel cell is prohibited when the hydrogen discharge valve is frozen as in the prior art described in Patent Document 1, a device for thawing the hydrogen discharge valve with some external heat source is required. There was a problem that the system became complicated.

  Moreover, even if the hydrogen-based discharge valve described in Patent Document 1 is frozen, the fuel cell is allowed to start, and the electric power from the fuel cell is supplied to the thawing heater of the hydrogen-based discharge valve to discharge the hydrogen-based discharge. In the start-up method in which the valve is heated and thawed, the power generated by the fuel cell is output to a drive device such as a drive motor of a vehicle equipped with the fuel cell together with the start of the fuel cell so that the fuel cell vehicle can run. It has become. However, after starting the fuel cell, the hydrogen discharge valve is thawed and the hydrogen side electrode is discharged until the hydrogen side electrode impurity gas is discharged to increase the hydrogen partial pressure in the hydrogen side electrode. The hydrogen partial pressure remains low, and the power generated by the fuel cell is also low. In this way, if the fuel cell vehicle starts running with low power generated by the fuel cell, the power generated by the fuel cell will be less than the vehicle required power before the hydrogen discharge valve is thawed. There is a case. In such a state, the traveling speed of the vehicle gradually decreases against the driver's intention, and in some cases, the vehicle may stop on the road due to the inability to generate power.

  It is an object of the present invention to prevent the generated power of a fuel cell from falling below the required traveling power after the fuel cell vehicle starts traveling.

  A fuel cell system according to the present invention includes a fuel cell for driving a vehicle that generates electric power by an electrochemical reaction between a fuel gas and an oxidant gas, a fuel gas supply channel that supplies fuel gas to a fuel electrode of the fuel cell, A discharge valve provided in a fuel gas discharge passage for discharging the reacted fuel gas from the fuel electrode of the fuel cell, and discharging a part of the reacted fuel gas to the atmosphere; and a discharge for detecting the state of the discharged valve A fuel cell system including a valve state detection unit and a control unit that performs opening / closing control of the discharge valve, wherein the control unit is configured to perform the discharge by the discharge valve state detection unit in a startup process of the fuel cell system. When the valve determines that the fuel gas after reaction cannot be discharged to the atmosphere, the valve has power transmission prohibiting means that does not transmit the power generated by the fuel cell to the vehicle drive device.

  The fuel cell system according to the present invention preferably includes a secondary battery, and the power transmission prohibiting means outputs the generated power of the fuel cell to the secondary battery, and the power transmission prohibiting means. Is preferable to hold the power connection device provided between the fuel cell and the drive device in a cut-off state, and the power transmission prohibiting means includes the fuel cell and the vehicle drive device. It is also preferable that the fuel cell and the vehicle drive device are not connected by fully opening the inverter circuit provided therebetween.

  Further, in the fuel cell system according to the present invention, the exhaust valve state detecting means is a temperature sensor attached to the exhaust valve, and the control unit is configured such that the temperature of the exhaust valve is equal to or lower than a predetermined temperature. The discharge valve is preferably determined to be in a state in which the reacted fuel gas cannot be discharged to the atmosphere, and the discharge valve state detection means has an opening degree attached to the discharge valve. A sensor, and when the opening command value of the discharge valve and the opening signal from the opening sensor of the discharge valve are different, the control unit discharges the fuel gas after the reaction of the discharge valve to the atmosphere. The exhaust valve state detecting means is a pressure sensor attached to the fuel gas discharge flow path, and the control unit is configured to detect the exhaust valve state. Open command If there is no difference in pressure of the fuel gas discharge channel before and after the said discharge valve to determine fuel gas after the reaction to be in the state where it can not be air emissions, it is also preferable.

  The present invention has an effect that it is possible to prevent the generated power of the fuel cell from falling below the required traveling power after the fuel cell vehicle starts traveling.

  A preferred embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic system diagram showing an embodiment according to the fuel cell system 10 of the present invention. In FIG. 1, a solid line indicates an electric system, a double line indicates a gas system such as air or hydrogen, and a one-dot chain line indicates a control system. As shown in FIG. 1, the fuel cell system 10 of the present embodiment uses air containing oxygen as the oxidant gas and hydrogen as the fuel gas. Air, which is an oxidant gas, is sucked into the air compressor 15 from the air through the air suction line 19 via the intake flow meter and the air filter, and the discharge air pressurized by the air compressor 15 is the oxidant of the fuel cell 11. It flows into the air side electrode 12 which is a pole. In the air that has entered the fuel cell from the air side electrode 12 of the fuel cell 11, oxygen is reduced by a power generation reaction with hydrogen supplied from the hydrogen system. The product water, which is a product of the reaction, increases in the air as water vapor or water droplets. The air whose water content has increased after the reaction is discharged to the air discharge pipe 24 of the fuel cell 11.

  Hydrogen gas, which is fuel gas, is stored in a hydrogen gas tank 31. Hydrogen is supplied from a hydrogen gas tank 31 to a hydrogen side electrode 13 which is a fuel side electrode of the fuel cell 11 through a hydrogen supply line 33. A part of the hydrogen supplied to the fuel cell 11 is consumed by reacting with oxygen in the air, which is an oxidant supplied to the air side electrode 12, but the unconsumed hydrogen enters the hydrogen system due to cross leak. After being discharged from the hydrogen discharge line 34 of the hydrogen side electrode 13 together with nitrogen and moisture, a hydrogen circulation pump 36 provided in a hydrogen circulation line 35 connecting the hydrogen discharge line 34 and the hydrogen supply line 33. Is recirculated to the hydrogen supply line 33. The hydrogen content consumed by power generation is replenished from the hydrogen gas tank 31 through the hydrogen supply pipe 33. The amount of hydrogen gas to be replenished is adjusted by the hydrogen gas supply control valve 32.

  As described above, since the hydrogen system is a circulation system, impurities such as nitrogen and moisture that cross-leak from the air side electrode 12 are concentrated when the hydrogen system is operated for a long time. Therefore, when such impurities have been concentrated to some extent, the hydrogen-based discharge valve 38 of the hydrogen-based atmospheric discharge line 39 connected to the hydrogen discharge line 34 is opened, and a predetermined amount of hydrogen gas is supplied to the hydrogen-based atmosphere. The hydrogen is released from the discharge line 39 to the outside air to increase the hydrogen partial pressure in the hydrogen system. The hydrogen-based exhaust valve 38 is provided with a temperature sensor 26 that is a hydrogen-based exhaust valve state detecting means. The temperature sensor 26 may be a thermocouple or an electric resistance type as long as it can continuously measure the temperature of the hydrogen discharge valve 38.

  From the air side electrode 12 and the hydrogen side electrode 13 of the fuel cell 11, the generated power of the fuel cell 11 is output by power output lines 41 a and 41 b, respectively. The power output lines 41 a and 41 b are connected to the inverter device 47. The inverter device 47 includes a plurality of switching inverter elements therein, and converts the direct current supplied from the fuel cell 11 into a driving three-phase alternating current. The power generated by the fuel cell 11 is converted into driving power for driving the vehicle by the inverter device 47 and supplied to the motor 49 for driving the vehicle. Further, power output lines 41a and 41b between the fuel cell 11 and the inverter device 47 include power supply lines 51a and 51b to the motor 16 of the air compressor 15 which is an auxiliary machine of the fuel cell 11, and hydrogen circulation. Power supply lines 53 a and 53 b are connected to the motor 37 of the pump 36, and each auxiliary machine is configured to operate according to the output of the fuel cell 11. An inverter device may be provided in the middle of the power supply lines 51a, 51b, 53a, 53b to the motors 16 and 37, and each motor may be driven by alternating current.

  Further, a DC / DC converter 43 is connected to the power output lines 41 a and 41 b between the fuel cell 11 and the inverter device 47, and a secondary battery 45 is connected to the DC / DC converter 43. The DC / DC converter 43 controls charging to the secondary battery 45 and discharging from the secondary battery 45.

  The state quantities of the temperature sensor 26, the control valves 32 and 38, the state quantities of the fuel cell 11, the air compressor 15, the motors 16 and 37 of the hydrogen circulation pump 36, etc. are all connected to the control unit 61. The measured value from the temperature sensor 26 is input to the control unit 61, which controls the opening commands of the control valves 32, 38, the rotational speed commands of the motors 16, 37, the inverter device 47, and the DC / DC converter 43. A control signal is output to control the entire fuel cell system 10. The control unit 61 includes a CPU and a storage unit, and may be configured to perform overall control by software, or may be configured to perform control by combining electric circuits. Further, data from the vehicle such as the running state of the vehicle and the addition of necessary requirements may be input to the control unit 61. A storage unit 63 that holds control data such as a control map necessary for the control operation is connected to the control unit 61 via a data bus 65.

  The operation of this embodiment will be described with reference to FIG. As shown in step S101 of FIG. 2, the control unit 61 activates the fuel cell 11 when the ignition key of the fuel cell vehicle is turned on regardless of the state of the hydrogen discharge valve 38 of the fuel cell 11. . As shown in step S <b> 102 of FIG. 2, the controller 61 acquires the temperature of the hydrogen discharge valve 38 from the signal from the temperature sensor 26 attached to the hydrogen discharge valve 38 after starting the fuel cell 11. Then, as shown in step S103 of FIG. 2, the control unit 61 determines whether or not the obtained hydrogen-based discharge valve 38 is in a state in which the hydrogen gas after the reaction cannot be discharged when the temperature is equal to or lower than a predetermined temperature. The predetermined temperature is a temperature at which it is determined whether or not the hydrogen-based discharge valve 38 can be opened and the hydrogen gas after the reaction can be discharged to the atmosphere. For example, the predetermined temperature may be 0 ° C. of the freezing point temperature. The freezing point temperature may be set to a constant value such as 5 ° C. with a margin for measurement and control, or may be variable depending on the outside air temperature. In the case of making it variable, the relationship between the outside air temperature or the like and a predetermined temperature may be made into a map or the like, stored in the storage unit 63, and made variable based on this map.

  In step S103 of FIG. 2, when the control unit 61 determines that the hydrogen gas after the reaction cannot be discharged due to freezing when the temperature of the hydrogen-based discharge valve 38 is equal to or lower than a predetermined temperature, step S106 of FIG. As shown in FIG. 4, the control unit 61 outputs a command for opening all the inverter elements to the inverter device 47. By this command, the inverter device 47 opens the circuits of all the inverter elements provided therein, disconnects the electrical connection between the fuel cell 11 and the vehicle drive motor 49, and uses the generated power of the fuel cell 11 to the vehicle. It is assumed that power cannot be transmitted to the drive motor 49.

  As shown in step S <b> 107 of FIG. 2, the control unit 61 outputs a command for setting the DC / DC converter 43 to the storage mode of the secondary battery 45 to the DC / DC converter 43. With this command, the DC / DC converter 43 operates to store the electrical output from the fuel cell 11 in the secondary battery 45.

  The fuel cell 11 started in a state in which the hydrogen gas after the reaction cannot be discharged from the hydrogen-based discharge valve 38 is in a warm-up operation state due to self-heating, but even in this state, power is continuously output by the power generation reaction. . The power generated by the fuel cell 11 is consumed by the motor 16 of the air compressor 15 and the motor 37 of the hydrogen circulation pump 36. Then, as shown in step S108 of FIG. 2, when power is generated in excess of the required drive power of the motors 16 and 37, the power flows into the DC / DC converter 43 from the power output lines 41a and 41b, and the DC / DC It flows from the DC converter 43 to the secondary battery 45 and is stored in the secondary battery 45. During this operation, the temperature of the fuel cell 11 rises due to self-heating by power generation, and the temperature of the hydrogen-based discharge valve 38 rises accordingly.

  Therefore, the control unit 61 returns to step S102 in FIG. 2, acquires the temperature of the hydrogen-based discharge valve 38, and reacts when the temperature of the hydrogen-based discharge valve 38 becomes equal to or higher than a predetermined temperature as shown in step S103 in FIG. It is determined whether or not the subsequent hydrogen gas can be discharged. As described above, the control unit 61 repeatedly executes the loop shown in steps S102, S103, and S106 to S108 in FIG. 2 to monitor whether or not the temperature of the hydrogen-based discharge valve 38 has risen to a predetermined temperature. At this time, in steps S106 to S108 in FIG. 2, the operation of the inverter device 47 and the DC / DC converter 43 is not changed by a command from the control unit 61 so that the storage mode for the secondary battery 45 is maintained. It becomes operation.

  As described above, the temperature of the hydrogen discharge valve 38 also rises due to the self-heating of the fuel cell 11, and therefore, after a certain amount of time has elapsed after the start of the fuel cell 11, the temperature of the hydrogen discharge valve 38 becomes higher. The temperature rises to the predetermined temperature described in (1).

  In step S103 of FIG. 2, when the control unit 61 determines that the temperature of the hydrogen-based discharge valve 38 is not frozen above a predetermined temperature and the hydrogen gas after the reaction can be discharged, As shown in step S <b> 104 of FIG. 2, the control unit 61 outputs a command that permits driving of the inverter device 47. By this command, the inverter element of the inverter device 47 is in a state where the switching operation can be started. As shown in step S105 of FIG. 2, the control unit sets the DC / DC converter 43 in the charge / discharge mode, and stores power in the secondary battery 45 when the generated power of the fuel cell 11 is equal to or higher than the power required for driving, etc. Conversely, when the power generated by the fuel cell 11 is less than the required power, the mode is switched to a mode in which power can be output from the secondary battery 45 to the vehicle drive motor 49. As a result, the power generated by the fuel cell 11 can be supplied to the motor 49 for driving the vehicle by the inverter device 47, and the fuel cell vehicle can travel. Since the hydrogen discharge valve 38 is not frozen, the hydrogen partial pressure of the hydrogen side electrode 13 of the fuel cell 11 can be increased by opening and closing the hydrogen discharge valve 38 to increase the generated power of the fuel cell 11. Therefore, it is possible to stably supply electric power necessary for traveling to the vehicle driving motor 49 that is a vehicle driving device after the fuel cell vehicle starts traveling.

  In the above-described embodiment, after the fuel cell 11 is started, the fuel is discharged until the temperature of the hydrogen discharge valve 38 becomes a predetermined temperature or higher and the hydrogen gas after the reaction can be discharged by opening and closing the fuel cell 11. Since the electric power generated from the battery 11 cannot be transmitted to the vehicle drive motor 49, when the hydrogen gas after the reaction cannot be discharged from the hydrogen discharge valve 38, the fuel cell vehicle cannot run. Yes. For this reason, the fuel cell vehicle does not travel in a state in which the hydrogen gas after the reaction cannot be discharged from the hydrogen-based discharge valve 38, and the generated power of the fuel cell is lower than the travel required power after the fuel cell vehicle starts traveling. There is an effect that this can be prevented. Further, excess power generated during the temperature rise of the fuel cell 11 can be stored in the secondary battery 45, and the power can be used as power for traveling, so that energy can be used effectively. There is an effect.

  The second embodiment will be described with reference to FIGS. 3 and 4. Parts similar to those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 3 is a system diagram of the fuel cell system according to the second embodiment. In the present embodiment, an opening degree sensor 28 that detects the opening degree of the hydrogen-based discharge valve 38 is provided as a state detection unit of the hydrogen-based discharge valve 38. The opening sensor 28 may be a position detector or a linear sensor that continuously detects the valve opening based on the amount of movement of the valve rod of the hydrogen-based discharge valve 38, or a signal indicating whether the valve is fully open or fully closed. A limit switch or the like that outputs may be used. In the present embodiment, a pressure sensor 27 for measuring the pressure is attached to the hydrogen discharge pipe 34 as a state detection unit of the hydrogen discharge valve 38. The pressure sensor 27 may be a piezoelectric or diaphragm type pressure sensor as long as it can continuously measure the pressure of the hydrogen discharge line 34. In the present embodiment, the circuit breaker 42 is located between the fuel cell 11 of the power output line 41 a and the inverter device 47 and can disconnect the connection of the power output line 41 a between the DC / DC converter 43 and the inverter device 47. Is attached. In FIG. 3, the circuit breaker 42 is attached to one power output line 41a, but may be attached to the other power output line 41b. The circuit breaker is a type of switch that mechanically disconnects the connection of the power output line 41a in accordance with a command from the control unit 61 to electrically disconnect the circuit. Other than the above description, the configuration is the same as that of the above-described embodiment.

  The operation of the second embodiment will be described with reference to FIG. The description of the same operation as that of the previous embodiment described in FIG. 2 is omitted. After starting the fuel cell 11 as shown in step S201 of FIG. 4, the control unit 61 outputs a valve opening command to the hydrogen discharge valve 38 as shown in step S202 of FIG. 4. By this valve opening command, the actuator of the hydrogen discharge valve 38 operates to try to open the hydrogen discharge valve 38. Next, as shown in step S <b> 203 of FIG. 4, the control unit 61 acquires the valve opening degree of the hydrogen discharge valve 38 based on a signal from the opening degree sensor 28 attached to the hydrogen discharge valve 38. And the control part 61 judges whether there exists a difference between an opening degree command value and the actual opening degree acquired from the opening degree sensor 28, as shown to step S204 of FIG. The judgment of the difference is that there is no difference if the difference between the two signals is within a predetermined error range, and there is a difference if the difference between the two signals exceeds the predetermined error range. Judge. The predetermined error range may be, for example, a few percent of the command value, or when the hydrogen discharge valve 38 is fully open and fully closed and the opening sensor 28 is a limit switch, the signal is turned ON. The determination may be made based on the difference between OFF and OFF.

  If there is a difference between the command value of the valve opening command of the hydrogen-based discharge valve 38 and the actual opening, the control unit 61 cannot open the hydrogen-based discharge valve 38 in a frozen state, and the hydrogen gas after the reaction cannot be opened. It is determined that the product cannot be discharged. Then, as shown in step S <b> 208 of FIG. 4, the control unit 61 outputs a break command to the breaker 42 so as to break the power output line 41 a. By this command, the circuit breaker 42 mechanically cuts off the connection of the power output line 41 a so that the power generated by the fuel cell 11 cannot be transmitted to the vehicle drive motor 49. Then, as shown in steps S209 and 210 of FIG. 4, the control unit 61 sets the DC / DC converter 43 to the DC / DC converter 43 and sets the DC / DC converter 43 to the secondary battery 45 to store the electric output from the fuel cell 11 as the secondary battery. 45 is charged.

  In addition, as shown in step S204 of FIG. 4, when there is no difference between the command value of the valve opening command of the hydrogen-based discharge valve 38 and the actual opening, the control unit 61 can open the hydrogen-based discharge valve 38. It is determined that the hydrogen gas after the reaction can be discharged. Then, as shown in step S <b> 205 of FIG. 4, the control unit 61 outputs a command to fully close the circuit breaker 42 to the circuit breaker 42. By this command, the circuit breaker 42 mechanically connects the power output line 41 a so that the power generated by the fuel cell 11 can be transmitted to the vehicle drive motor 49.

  As shown in steps S206 and S207 of FIG. 4, the control unit 61 starts the operation of the inverter device 47, sets the DC / DC converter 43 in the charge / discharge mode, and drives the generated power of the fuel cell 11 by the inverter device 47. The fuel cell vehicle can be driven by being converted into electric power and supplied to the vehicle drive motor 49.

  In the second embodiment described above, in addition to the effects of the embodiment described above, the actual opening of the hydrogen-based discharge valve 38 is detected by the opening sensor 28, and the valve can be opened and closed based on the signal. Since it is determined whether or not the hydrogen gas can be discharged after the reaction, the state of the hydrogen-based discharge valve 38 can be determined more reliably than the determination based only on the temperature. In addition, since the power output line 41a is mechanically interrupted by the circuit breaker 42, the power transmission to the vehicle drive motor 49 is interrupted, so that the power transmission is reliably interrupted and the hydrogen-based discharge valve 38 is more reliably Thus, it is possible to prevent the fuel cell vehicle from traveling in a state in which the hydrogen gas after the reaction cannot be discharged.

  The third embodiment will be described with reference to FIG. The system configuration of the third embodiment is the same as that of the second embodiment described above. Also, the description of the same operation as in the second embodiment is omitted. The controller 61 starts the fuel cell 11 as shown in step S301 of FIG. 5 and then outputs a valve opening command to the hydrogen discharge valve 38 by the pressure sensor 27 as shown in step S302 of FIG. The pressure of the hydrogen discharge pipe 34 is acquired and stored in the storage unit 63. Then, as shown in step S303 in FIG. 5, the control unit 61 outputs a valve opening command to the hydrogen discharge valve 38 and attempts to open the hydrogen discharge valve 38. Thereafter, as shown in step S <b> 304 of FIG. 5, the control unit 61 acquires the pressure of the hydrogen discharge pipe 34 after outputting the valve opening command to the hydrogen-based discharge valve 38 and stores it in the storage unit 63. When the hydrogen discharge valve 38 is actually opened by the previous valve opening command, the pressure after the valve opening command is lower than the pressure before the valve opening command, and when the valve is not opened, the valve opening command The subsequent pressure and the pressure before the valve opening command are substantially equal. As shown in step S305 in FIG. 5, the control unit 61 stores the pressure of the hydrogen discharge line 34 and the hydrogen-based discharge previously stored in the storage unit 63 before outputting the valve opening command to the hydrogen-based discharge valve 38. Data on the pressure of the hydrogen discharge pipe 34 after outputting the valve opening command to the valve 38 is acquired from the storage unit 63 and compared. It is then determined whether there is a difference between the two pressures. The judgment of the difference is that there is no difference if the difference between the two signals is within a predetermined error range, and there is a difference if the difference between the two signals exceeds the predetermined error range. Judge. For example, the predetermined error range may be a few percent of the measured pressure, or may be a constant value.

  When there is no difference between the two pressures, the control unit 61 determines that the hydrogen-based discharge valve 38 cannot be opened and the hydrogen gas after the reaction cannot be discharged. If there is a difference in pressure, it is determined that the hydrogen-based discharge valve 38 is open and the hydrogen gas after the reaction can be discharged. The power transmission prohibiting means after detecting the state of the hydrogen-based discharge valve 38 is a device that fully opens the inverter element of the inverter device 47 and interrupts power transmission to the vehicle drive motor, similar to that described with reference to FIG. Moreover, this power transmission interruption may be performed by the circuit breaker 42 as in the second embodiment.

  In the third embodiment described above, in addition to the embodiment described above, the pressure sensor 27 necessary for the operation of the fuel cell 11 can be used without attaching a sensor to the hydrogen discharge valve 38. Since the state of the discharge valve 38 can be acquired, the system can be simplified.

It is a control system diagram showing an embodiment of a fuel cell system according to the present invention. 4 is a flowchart showing a start-up process in the embodiment of the fuel cell system according to the present invention. It is a control system diagram which shows 2nd Embodiment of the fuel cell system which concerns on this invention. 6 is a flowchart showing a start-up process in the second embodiment of the fuel cell system according to the present invention. 6 is a flowchart showing a start-up process in the third embodiment of the fuel cell system according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell system, 11 Fuel cell, 12 Air side electrode, 13 Hydrogen side electrode, 15 Air compressor, 16, 37 Motor, 19 Air suction line, 23 Air supply line, 24 Air discharge line, 26 Temperature sensor , 27 Pressure sensor, 28 Valve opening sensor, 31 Hydrogen gas tank, 32 Hydrogen supply control valve, 33 Hydrogen supply line, 34 Hydrogen discharge line, 35 Hydrogen circulation line, 36 Hydrogen circulation pump, 38 Hydrogen system discharge valve, 39 Hydrogen-based atmospheric discharge pipe, 41, 41a, 41b Power output line, 42 Circuit breaker, 43 DC / DC converter, 45 Secondary battery, 47 Inverter device, 49 Vehicle drive motor, 51a, 51b, 53a, 53b Electric power Supply line, 61 control unit, 63 storage unit, 65 data bus.

Claims (7)

A fuel cell for driving a vehicle that generates electricity by an electrochemical reaction between a fuel gas and an oxidant gas;
A fuel gas supply channel for supplying fuel gas to the fuel electrode of the fuel cell;
A discharge valve provided in a fuel gas discharge passage for discharging the reacted fuel gas from the fuel electrode of the fuel cell, and discharging a part of the reacted fuel gas to the atmosphere;
A discharge valve state detecting means for detecting the state of the discharge valve;
A control unit for performing opening / closing control of the discharge valve;
A fuel cell system comprising:
In the starting process of the fuel cell system, the control unit determines that the exhaust valve state detection means determines that the exhaust valve cannot discharge the reacted fuel gas to the atmosphere. A fuel cell system comprising: a power transmission prohibiting unit that does not transmit the power generated by the battery to the vehicle drive device. The fuel cell system according to claim 1, wherein
A secondary battery,
The power transmission prohibiting means outputs the power generated by the fuel cell to the secondary battery. The fuel cell system according to claim 1 or 2,
The power transmission prohibiting unit holds a power connection device provided between the fuel cell and the driving device in a cut-off state. The fuel cell system according to any one of claims 1 to 3,
The fuel cell system characterized in that the power transmission prohibiting means fully opens an inverter circuit provided between the fuel cell and the vehicle drive device, and does not connect the fuel cell and the vehicle drive device. The fuel cell system according to any one of claims 1 to 4,
The discharge valve state detection means is a temperature sensor attached to the discharge valve,
When the temperature of the discharge valve is equal to or lower than a predetermined temperature, the control unit determines that the discharge valve cannot discharge the reacted fuel gas to the atmosphere. system. The fuel cell system according to any one of claims 1 to 5,
The discharge valve state detection means is an opening sensor attached to the discharge valve,
The control unit cannot discharge the fuel gas after the reaction to the atmosphere when there is a difference between the opening command value of the discharge valve and the opening signal from the opening sensor of the discharge valve. A fuel cell system characterized in that it is determined to be in a state. The fuel cell system according to any one of claims 1 to 6,
The discharge valve state detection means is a pressure sensor attached to the fuel gas discharge flow path,
When there is no difference in the pressure of the fuel gas discharge flow path before and after outputting an open command to the discharge valve, the control unit is in a state in which the discharge valve cannot discharge the reacted fuel gas to the atmosphere. A fuel cell system characterized by being judged to be present.

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