WO2013129241A1 - Fuel cell system and method for controlling fuel cell system - Google Patents

Fuel cell system and method for controlling fuel cell system Download PDF

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Publication number
WO2013129241A1
WO2013129241A1 PCT/JP2013/054404 JP2013054404W WO2013129241A1 WO 2013129241 A1 WO2013129241 A1 WO 2013129241A1 JP 2013054404 W JP2013054404 W JP 2013054404W WO 2013129241 A1 WO2013129241 A1 WO 2013129241A1
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WO
WIPO (PCT)
Prior art keywords
fuel cell
pressure
anode gas
anode
gas pressure
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PCT/JP2013/054404
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French (fr)
Japanese (ja)
Inventor
森山　明信
祥朋 浅井
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日産自動車株式会社
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Application filed by 日産自動車株式会社 filed Critical 日産自動車株式会社
Priority to JP2014502170A priority Critical patent/JP5858137B2/en
Publication of WO2013129241A1 publication Critical patent/WO2013129241A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04097—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with recycling of the reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
    • H01M8/04156—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying with product water removal
    • H01M8/04179—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying with product water removal by purging or increasing flow or pressure of reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04231—Purging of the reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2250/00—Fuel cells for particular applications; Specific features of fuel cell system
    • H01M2250/20—Fuel cells in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04858—Electric variables
    • H01M8/04895—Current
    • H01M8/04917—Current of auxiliary devices, e.g. batteries, capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04858—Electric variables
    • H01M8/04925—Power, energy, capacity or load
    • H01M8/04947—Power, energy, capacity or load of auxiliary devices, e.g. batteries, capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/40—Application of hydrogen technology to transportation, e.g. using fuel cells

Definitions

  • the present invention relates to a technique for controlling a standby current of a pressure regulating valve that controls the pressure of an anode gas supplied to a fuel cell.
  • the pressure of the anode gas supplied to the fuel cell is controlled by periodically opening and closing a pressure regulating valve provided in the anode gas supply passage for supplying the anode gas to the fuel cell.
  • a technique for performing pulsation operation that periodically increases or decreases is known (see JP2008-97966A).
  • JP 2008-97966A has no description about the standby current flowing through the pressure regulating valve.
  • the present invention improves the responsiveness of the anode gas supplied to the fuel cell while maintaining the standby current flowing through the pressure regulating valve.
  • An object of the present invention is to provide a technique capable of suppressing an increase in current consumption caused by the current consumption.
  • a fuel cell system is configured to set a target anode gas pressure in a fuel cell that periodically increases and decreases, and to increase the target anode gas pressure from a predetermined period before the anode in the fuel cell based on the target anode gas pressure.
  • a standby current is passed through a pressure regulating valve that regulates the gas pressure.
  • FIG. 1A is a perspective view of the fuel cell for explaining the configuration of the fuel cell system in the first embodiment.
  • FIG. 1B is a diagram for explaining the configuration of the fuel cell system according to the first embodiment, and is a cross-sectional view taken along the line 1B-1B of the fuel cell of FIG. 1A.
  • FIG. 2 is a schematic configuration diagram of an anode gas non-circulating fuel cell system according to the first embodiment.
  • FIG. 3 is a diagram for explaining pulsation operation during steady operation in which the operation state of the fuel cell system is constant.
  • FIG. 4 is a flowchart of standby current control performed in the fuel cell system according to the first embodiment.
  • FIG. 5 is a flowchart showing a detailed calculation method of the target value of the anode pressure.
  • FIG. 6 is a diagram showing the relationship between the target current (target output) of the fuel cell stack, the pulsation upper limit target value, and the pulsation lower limit target value.
  • FIG. 7 is a time chart of standby current control performed in the fuel cell system according to the first embodiment.
  • FIG. 8 is a flowchart of standby current control performed in the fuel cell system according to the second embodiment.
  • FIG. 9 is a diagram illustrating an example of the relationship between the output current of the fuel cell stack and the anode pressure.
  • FIG. 10 is a flowchart of standby current control performed in the fuel cell system according to the third embodiment.
  • FIG. 11 is a flowchart of standby current control performed in the fuel cell system according to the fourth embodiment.
  • FIG. 12 is a diagram showing a time chart of standby current control performed in the fuel cell system according to the fourth embodiment.
  • FIG. 13 is another flowchart of standby current control performed in the fuel cell system according to the first embodiment.
  • an electrolyte membrane is sandwiched between an anode electrode (fuel electrode) and a cathode electrode (oxidant electrode), an anode gas containing hydrogen in the anode electrode (fuel gas), and a cathode gas containing oxygen in the cathode electrode (oxidant) Electricity is generated by supplying gas.
  • the electrode reaction that proceeds in both the anode electrode and the cathode electrode is as follows.
  • the fuel cell generates an electromotive force of about 1 volt by the electrode reaction of the formulas (1) and (2).
  • FIG. 1A and 1B are diagrams for explaining the configuration of the fuel cell system according to the first embodiment.
  • FIG. 1A is a perspective view of the fuel cell 10.
  • 1B is a 1B-1B cross-sectional view of the fuel cell of FIG. 1A.
  • the fuel cell 10 includes an anode separator 12 and a cathode separator 13 arranged on both front and back surfaces of a membrane electrode assembly (hereinafter referred to as “MEA”) 11.
  • MEA membrane electrode assembly
  • the MEA 11 includes an electrolyte membrane 111, an anode electrode 112, and a cathode electrode 113.
  • the MEA 11 has an anode electrode 112 on one surface of the electrolyte membrane 111 and a cathode electrode 113 on the other surface.
  • the electrolyte membrane 111 is a proton conductive ion exchange membrane formed of a fluorine-based resin.
  • the electrolyte membrane 111 exhibits good electrical conductivity in a wet state.
  • the anode electrode 112 includes a catalyst layer 112a and a gas diffusion layer 112b.
  • the catalyst layer 112a is in contact with the electrolyte membrane 111.
  • the catalyst layer 112a is formed of carbon black particles carrying platinum or platinum.
  • the gas diffusion layer 112b is provided outside the catalyst layer 112a (on the opposite side of the electrolyte membrane 111) and is in contact with the anode separator 12.
  • the gas diffusion layer 112b is formed of a member having sufficient gas diffusibility and conductivity, and is formed of, for example, a carbon cloth woven with yarns made of carbon fibers.
  • the cathode electrode 113 includes a catalyst layer 113a and a gas diffusion layer 113b.
  • the anode separator 12 is in contact with the gas diffusion layer 112b.
  • the anode separator 12 has a plurality of groove-like anode gas passages 121 for supplying anode gas to the anode electrode 112 on the side in contact with the gas diffusion layer 112b.
  • the cathode separator 13 is in contact with the gas diffusion layer 113b.
  • the cathode separator 13 has a plurality of groove-like cathode gas flow paths 131 for supplying cathode gas to the cathode electrode 113 on the side in contact with the gas diffusion layer 113b.
  • the anode gas flowing through the anode gas channel 121 and the cathode gas flowing through the cathode gas channel 131 flow in the same direction in parallel with each other. You may make it flow in the opposite direction in parallel with each other.
  • FIG. 2 is a schematic configuration diagram of the anode gas non-circulating fuel cell system 1 according to the first embodiment.
  • the fuel cell system 1 includes a fuel cell stack 2, an anode gas supply device 3, and a controller 4.
  • the fuel cell stack 2 is formed by stacking a plurality of fuel cells 10, generates electric power by receiving supply of anode gas and cathode gas, and generates electric power necessary for driving a vehicle (for example, electric power necessary for driving a motor). ).
  • the cathode gas supply / discharge device for supplying and discharging the cathode gas to / from the fuel cell stack 2 and the cooling device for cooling the fuel cell stack 2 are not the main part of the present invention, and are not shown for the sake of easy understanding. did. In this embodiment, air is used as the cathode gas.
  • the anode gas supply device 3 includes a high-pressure tank 31, an anode gas supply passage 32, a pressure regulating valve 33, a pressure sensor 34, an anode gas discharge passage 35, a buffer tank 36, a purge passage 37, and a purge valve 38. .
  • the high pressure tank 31 stores the anode gas supplied to the fuel cell stack 2 in a high pressure state.
  • the anode gas supply passage 32 is a passage for supplying the anode gas discharged from the high-pressure tank 31 to the fuel cell stack 2, and has one end connected to the high-pressure tank 31 and the other end of the fuel cell stack 2. Connected to the anode gas inlet hole 21.
  • the pressure regulating valve 33 is provided in the anode gas supply passage 32.
  • the pressure regulating valve 33 adjusts the anode gas discharged from the high-pressure tank 31 to a desired pressure and supplies it to the fuel cell stack 2.
  • the pressure regulating valve 33 is an electromagnetic valve whose opening degree can be adjusted continuously or stepwise, and the opening degree is controlled by the controller 4.
  • the controller 4 controls the opening degree of the pressure regulating valve 33 by controlling the amount of current supplied to the pressure regulating valve 33.
  • the pressure sensor 34 is provided in the anode gas supply passage 32 downstream of the pressure regulating valve 33.
  • the pressure sensor 34 detects the pressure of the anode gas flowing through the anode gas supply passage 32 downstream of the pressure regulating valve 33.
  • the pressure of the anode gas detected by the pressure sensor 34 is the pressure of the entire anode system including the anode gas flow paths 121 and the buffer tanks 36 inside the fuel cell stack (hereinafter referred to as “anode pressure”). As a substitute.
  • the anode gas discharge passage 35 has one end connected to the anode gas outlet hole 22 of the fuel cell stack 2 and the other end connected to the upper portion of the buffer tank 36.
  • the anode gas discharge passage 35 has a mixed gas of excess anode gas that has not been used for the electrode reaction and an impure gas such as nitrogen or water vapor that has cross-leaked from the cathode side to the anode gas passage 121 (hereinafter referred to as “anode”). Off-gas ”) is discharged.
  • the buffer tank 36 temporarily stores the anode off gas flowing through the anode gas discharge passage 35. A part of the water vapor in the anode off gas is condensed in the buffer tank 36 to become liquid water and separated from the anode off gas.
  • One end of the purge passage 37 is connected to the lower part of the buffer tank 36.
  • the other end of the purge passage 37 is an open end.
  • the anode off gas and liquid water stored in the buffer tank 36 are discharged from the opening end to the outside air through the purge passage 37.
  • the purge valve 38 is provided in the purge passage 37.
  • the purge valve 38 is an electromagnetic valve whose opening degree can be adjusted continuously or stepwise, and the opening degree is controlled by the controller 4.
  • the opening of the purge valve 38 By adjusting the opening of the purge valve 38, the amount of anode off-gas discharged from the buffer tank 36 to the outside air via the purge passage 37 is adjusted, and the anode gas concentration in the buffer tank 36 is adjusted to be a certain level or less. To do. This is because if the concentration of the anode gas in the buffer tank 36 becomes too high, the amount of the anode gas discharged from the buffer tank 36 through the purge passage 37 to the outside air increases and is wasted.
  • the controller 4 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).
  • CPU central processing unit
  • ROM read only memory
  • RAM random access memory
  • I / O interface input / output interface
  • the controller 4 includes a current sensor 41 that detects the output current of the fuel cell stack 2 and a temperature of cooling water that cools the fuel cell stack 2 (hereinafter referred to as “cooling water temperature”). Signals for detecting the operating state of the fuel cell system 1, such as the temperature sensor 42 to detect and the accelerator stroke sensor 43 to detect the amount of depression of the accelerator pedal (hereinafter referred to as “accelerator operation amount”) are input.
  • the controller 4 periodically opens and closes the pressure regulating valve 33 based on these input signals, performs pulsation operation to periodically increase and decrease the anode pressure, and adjusts the opening degree of the purge valve 38 from the buffer tank 36.
  • the flow rate of the anode off gas to be discharged is adjusted, and the anode gas concentration in the buffer tank 36 is kept below a certain level.
  • the fuel cell stack 2 In the case of the anode gas non-circulation type fuel cell system 1, if the anode gas continues to be supplied from the high-pressure tank 31 to the fuel cell stack 2 while the pressure regulating valve 33 is kept open, the fuel cell stack 2 is not discharged. Since the anode off gas including the used anode gas is continuously discharged from the buffer tank 36 through the purge passage 37 to the outside air, it is wasted.
  • the pulsation operation is performed in which the pressure regulating valve 33 is periodically opened and closed to increase and decrease the anode pressure periodically.
  • the anode off gas accumulated in the buffer tank 36 can be caused to flow back to the fuel cell stack 2 when the anode pressure is reduced.
  • the anode gas in the anode off-gas can be reused, so that the amount of the anode gas discharged to the outside air can be reduced and waste can be eliminated.
  • FIG. 3 is a diagram for explaining pulsation operation during steady operation in which the operation state of the fuel cell system 1 is constant.
  • the controller 4 calculates the target output of the fuel cell stack 2 based on the operating state of the fuel cell system 1 (the load of the fuel cell stack), and sets the anode pressure according to the target output. Set the upper and lower limits. Then, the anode pressure is periodically increased or decreased between the upper limit value and the lower limit value of the set anode pressure.
  • the pressure regulating valve 33 is opened to an opening at which the anode pressure can be increased to at least the upper limit value.
  • the anode gas is supplied from the high-pressure tank 31 to the fuel cell stack 2 and discharged to the buffer tank 36.
  • the pressure regulating valve 33 When the anode pressure reaches the upper limit at time t2, the pressure regulating valve 33 is fully closed as shown in FIG. 3B, and the supply of anode gas from the high-pressure tank 31 to the fuel cell stack 2 is stopped. Then, since the anode gas left in the anode gas flow path 121 inside the fuel cell stack is consumed over time due to the electrode reaction of (1) described above, the anode pressure is reduced by the consumed amount of the anode gas.
  • the pressure in the buffer tank 36 temporarily becomes higher than the pressure in the anode gas flow path 121, so that the anode gas flow path 121 extends from the buffer tank 36.
  • the anode off-gas flows back into.
  • the anode gas left in the anode gas channel 121 and the anode gas in the anode off-gas that has flowed back to the anode gas channel 121 are consumed over time, and the anode pressure further decreases.
  • the pressure regulating valve 33 When the anode pressure reaches the lower limit at time t3, the pressure regulating valve 33 is opened in the same manner as at time t1. When the anode pressure reaches the upper limit again at time t4, the pressure regulating valve 33 is fully closed.
  • the standby current is allowed to flow from a predetermined time before the start of increasing the anode pressure, thereby improving the responsiveness of the anode gas supply and suppressing the power consumption.
  • the standby current is a current that flows when the pressure regulating valve 33 is not fully opened.
  • FIG. 4 is a flowchart of standby current control performed in the fuel cell system according to the first embodiment. The process starting from step S10 is performed by the controller 4.
  • step S10 a target value for the anode pressure is calculated.
  • a detailed calculation method of the target value of the anode pressure will be described with reference to the flowchart shown in FIG.
  • step S11 of the flowchart shown in FIG. 5 a pulsation upper limit target value and a pulsation lower limit target value during pulsation operation control for periodically increasing and decreasing the anode pressure are generated.
  • FIG. 6 is a diagram showing the relationship between the target current (target output) of the fuel cell stack 2, the pulsation upper limit target value, and the pulsation lower limit target value.
  • the controller 4 calculates the target current (target output) of the fuel cell stack 2 based on the operating state of the fuel cell system 1, and calculates the calculated target current (target output) and the target current and pulsation target value shown in FIG.
  • the pulsation upper limit target value and the pulsation lower limit target value are generated based on the relationship map.
  • step S12 of FIG. 5 it is determined whether or not the target value of the anode pressure is lower than the anode pressure detected by the pressure sensor 34.
  • the initial value of the anode pressure target value is, for example, the pulsation upper limit target value. If it is determined that the target value of the anode pressure is lower than the anode pressure detected by the pressure sensor 34, the process proceeds to step S13, and if it is determined that the target value of the anode pressure is greater than or equal to the anode pressure detected by the pressure sensor 34, step S14 is performed. Proceed to
  • step S13 the target value of the anode pressure is set as the pulsation lower limit target value.
  • step S14 the anode pressure target value is set as the pulsation upper limit target value.
  • step S20 of the flowchart shown in FIG. 4 it is determined whether or not the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure calculated in step S10 is a predetermined value or less. If it is determined that the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or less than a predetermined value, the process proceeds to step S40, and a standby current is supplied to the pressure regulating valve 33. On the other hand, if it is determined that the differential pressure is greater than the predetermined value, the process proceeds to step S30.
  • step S30 it is determined whether or not the target value of the anode pressure calculated in step S20 is higher than the anode pressure detected by the pressure sensor 34. If it is determined that the target value of the anode pressure is higher than the anode pressure detected by the pressure sensor 34, the process proceeds to step S40, and a standby current is caused to flow through the pressure regulating valve 33. On the other hand, if it is determined that the target value of the anode pressure is equal to or lower than the anode pressure detected by the pressure sensor 34, the process proceeds to step S50 and the standby current is set to zero.
  • FIG. 7 is a diagram showing a time chart of standby current control performed in the fuel cell system according to the first embodiment.
  • the temporal change of the anode pressure, the temporal change of the standby current, and the temporal change of the current supplied to the pressure regulating valve 33 are shown in order from the top.
  • the target value of the anode pressure is controlled to be alternately switched between the upper limit value and the lower limit value, and the actual anode pressure changes to follow the target value of the anode pressure.
  • the anode pressure (conventional example) indicated by the dotted line is an example in which the standby current is zero when the target value of the anode pressure is the lower limit, that is, when the pressure regulating valve 33 is fully closed.
  • a standby current is caused to flow through the pressure regulating valve 33.
  • FIG. 7 in order to follow the target value of the anode pressure, the difference between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure at time t11 while the actual anode pressure is decreasing is shown. In accordance with the predetermined value, a standby current is flowing.
  • the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or lower than the predetermined value.
  • the standby current continues to flow.
  • the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes higher than the predetermined value, so that the standby The current becomes zero.
  • a short time before the target value of the anode pressure changes from the lower limit value to the upper limit value specifically, the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure.
  • the differential pressure becomes a predetermined value or less
  • the standby current flows, so that the followability when the anode pressure is increased can be improved.
  • the difference between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or lower than a predetermined value. Since the standby current is set to zero, the power consumption can be reduced compared to the case where the standby current is always supplied when the pressure regulating valve 33 is fully closed.
  • the standby current is made to flow when the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less.
  • the ratio of the anode pressure detected by the pressure sensor 34 to the value (the detected anode pressure / the lower limit target value of the anode pressure) is equal to or less than a predetermined ratio
  • the standby current may flow.
  • the pulsation width at the time of pulsation operation control of the anode pressure fluctuates, so that the standby current is based on the ratio of the anode pressure detected by the pressure sensor 34 to the lower limit target value of the anode pressure. It is possible to flow the standby current at a more appropriate timing when the timing of flowing the current is determined.
  • the control valve 33 waits for a predetermined period before the target value of the anode gas pressure is increased. Since the current flows, the responsiveness of the anode pressure at the time of boosting can be improved. In addition, the current consumption can be suppressed as compared with the case where the standby current is always kept flowing when the pressure regulating valve 33 is fully closed.
  • a standby current flows through the pressure regulating valve 33.
  • the standby current can be made to flow at an appropriate timing in consideration of a reduction in current consumption caused by the standby current.
  • the ratio of the anode pressure to the lower limit target value of the anode pressure at the time of pulsation operation control is equal to or less than a predetermined ratio, according to the method of flowing the standby current to the pressure regulating valve 33, the responsiveness improvement of the anode pressure at the time of pressure increase,
  • the standby current can be made to flow at an appropriate timing in consideration of a reduction in current consumption caused by the standby current.
  • the standby current can flow at a more appropriate timing.
  • control shown in FIG. 4 may be performed when the output of the fuel cell is equal to or lower than the predetermined output and the lower limit target value of the pressure of the anode gas during the pulsation operation control is within the predetermined range.
  • the timing of supplying the standby current based on the differential pressure between the anode pressure detected by the pressure sensor 34 and the lower limit target value of the anode pressure. Therefore, the standby current can be supplied at a more appropriate timing.
  • the threshold value for determining the timing for flowing the standby current is changed based on the response delay of the actual anode pressure with respect to the target anode pressure when the anode pressure is increased.
  • FIG. 8 is a flowchart of standby current control performed in the fuel cell system according to the second embodiment. The process starting from step S100 is performed by the controller 4.
  • step S100 it is determined whether the output of the fuel cell stack 2 is equal to or lower than a predetermined output. If it is determined that the output of the fuel cell stack 2 is greater than the predetermined output, the process returns to step S100. If it is determined that the output is equal to or less than the predetermined output, the process proceeds to step S110.
  • step S110 it is determined whether or not it is a pressure increasing process during pulsation control of the anode pressure. If it is determined that it is a step-down process, the process returns to step S100, and if it is determined that it is a step-up process, the process proceeds to step S120.
  • step S120 it is determined whether or not the differential pressure between the target value of the anode pressure and the anode pressure detected by the pressure sensor 34 is equal to or less than a predetermined value. If it is determined that the differential pressure is equal to or less than the predetermined value, the process proceeds to step S130, and if it is determined that the differential pressure is higher than the predetermined value, the process proceeds to step S140.
  • step S130 the predetermined value used in the determination in step S120 is decreased. Thereby, compared with the time before making a predetermined value small, since the timing which sends standby electric current can be delayed, power consumption can be reduced.
  • step S140 it is determined that the response delay of the actual anode pressure with respect to the target anode pressure at the time of increasing the anode pressure has increased, and the predetermined value used in step S120 is the previous predetermined value, that is, the predetermined value before being reduced. Return to value.
  • the timing of flowing the standby current can be advanced, so that the response of the actual anode pressure to the target anode pressure when the anode pressure is increased can be improved.
  • FIG. 9 is a diagram showing an example of the relationship between the output current of the fuel cell stack 2 and the anode pressure.
  • the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant (within a predetermined range) regardless of the magnitude of the output current.
  • the region where the output current of the fuel cell stack 2 is small is, for example, when the fuel cell vehicle is idling or traveling at a low speed.
  • the predetermined used for determining the timing of flowing the standby current in the region where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant, that is, the region where the output of the fuel cell stack 2 is equal to or lower than the predetermined output. Correct the value. Since the followability of the actual anode pressure with respect to the target anode pressure is determined in a stable state where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant, the timing for correcting the predetermined value can be accurately determined, The value can be corrected effectively.
  • the predetermined value may be corrected even when the output of the fuel cell stack 2 is larger than the predetermined output.
  • the predetermined value is corrected based on the deviation between the target value of the anode gas pressure and the pressure of the anode gas. Based on this, it is possible to appropriately set the timing for flowing the standby current.
  • the predetermined value is corrected when the output of the fuel cell is equal to or lower than the predetermined output, the predetermined value is accurately corrected in a stable state where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant. Can do.
  • control for flowing a standby current may be performed.
  • the same correction can be performed. That is, if the deviation between the target value of the anode gas pressure and the anode gas pressure is less than or equal to a predetermined value, the predetermined ratio is reduced, and if the deviation is larger than the predetermined value, the predetermined ratio is set to the previous value, that is, Return to the previous value.
  • the magnitude of the standby current is changed based on the response delay of the actual anode pressure with respect to the target anode pressure when the anode pressure is increased.
  • FIG. 10 is a flowchart of standby current control performed in the fuel cell system according to the third embodiment. Steps for performing the same processes as those in the flowchart shown in FIG. 8 are denoted by the same reference numerals, and detailed description thereof is omitted. The process of the flowchart shown in FIG.
  • step S120 If it is determined in step S120 that the differential pressure between the target value of the anode pressure and the anode pressure detected by the pressure sensor 34 is equal to or less than the predetermined value, the process proceeds to step S210, and if it is determined that the pressure is higher than the predetermined value, the process proceeds to step S220. move on.
  • step S210 the standby current is reduced. That is, since the followability of the actual anode pressure with respect to the target anode pressure at the time of increasing the anode pressure is good, the power consumption is reduced by reducing the magnitude of the standby current.
  • step S220 it is determined that the response delay of the actual anode pressure with respect to the target anode pressure at the time of increasing the anode pressure has increased, and the magnitude of the standby current is the previous magnitude, that is, the magnitude before being reduced. Return to (increase). Thereby, the responsiveness of the actual anode pressure with respect to the target anode pressure when the anode pressure is increased can be improved.
  • the magnitude of the standby current is corrected in a region where the pulsation upper limit pressure and pulsation lower limit pressure of the anode pressure are constant, that is, in a region where the output of the fuel cell stack 2 is equal to or less than a predetermined output. Since the followability of the actual anode pressure with respect to the target anode pressure is determined in a stable state where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant, it is possible to accurately determine the timing for correcting the magnitude of the standby current. Thus, it is possible to effectively correct the standby current.
  • the magnitude of the standby current is corrected when the output of the fuel cell stack 2 is equal to or less than a predetermined output.
  • the magnitude of the standby current may be corrected.
  • the standby current is corrected based on the deviation between the target value of the anode gas pressure and the anode gas pressure.
  • a standby current can flow.
  • control for flowing a standby current may be performed.
  • the same correction can be performed. That is, if the deviation between the target value of the anode gas pressure and the anode gas pressure is less than or equal to a predetermined value, the standby current is reduced, and if the deviation is greater than the predetermined value, the standby current is reduced to the previous value, that is, the current. Revert to previous value.
  • the standby current is set to zero.
  • the standby current is zero, and the fuel cell stack 2 before the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less.
  • FIG. 11 is a flowchart of standby current control performed in the fuel cell system according to the fourth embodiment. Steps for performing the same processing as the processing in the flowchart shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. The process of the flowchart shown in FIG. 11 is also performed by the controller 4.
  • step S300 it is determined whether there is an output increase command for the fuel cell stack 2 or not. For example, when the accelerator of the fuel cell vehicle is depressed more than a predetermined opening, an output increase command for the fuel cell stack 2 is generated. If it is determined that there is an output increase command for the fuel cell stack 2, the process proceeds to step S40, and a standby current is supplied. On the other hand, if there is no output increase command for the fuel cell stack 2, the process proceeds to step S50, and the standby current is set to zero.
  • FIG. 12 is a diagram showing a time chart of standby current control performed in the fuel cell system according to the fourth embodiment.
  • the time change of the accelerator opening of the fuel cell vehicle, the time change of the anode pressure, the time change of the standby current, and the time change of the current supplied to the pressure regulating valve 33 are shown in order from the top.
  • the target value of the anode pressure is controlled to be alternately switched between the upper limit value and the lower limit value, and the actual anode pressure is changed so as to follow the target value of the anode pressure.
  • the target value at the time of lowering is changed in a rectangular pulse shape from the upper limit value to the lower limit value, but the target value at the time of boosting is gradually increased from the lower limit value to the upper limit value. .
  • the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes higher than the predetermined value, so that the standby The current becomes zero.
  • the target value of the anode pressure increases after the accelerator opening increases and the output increase command of the fuel cell stack 2 is generated, the target value of the anode pressure is determined after the output increase command of the fuel cell stack 2 is generated. There is a time lag before it grows. In particular, in the control system in which the target value of the anode pressure at the time of boosting is gradually increased as in this embodiment, the time lag is increased. However, in this embodiment, the output increase command of the fuel cell stack 2 is generated even if the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is not less than a predetermined value. As a result, a standby current is caused to flow through the pressure regulating valve 33, so that the output responsiveness of the fuel cell stack 2 can be improved.
  • the pressure regulating valve 33 is put on standby. Since the current flows, the output responsiveness of the fuel cell stack 2 can be improved.
  • the case where the accelerator of the fuel cell vehicle is depressed more than a predetermined opening is given, but when the brake is released or the shift lever is set to P (parking) or N It may also be the case when shifting from the (neutral) state to D (drive) or R (reverse).
  • the present invention is not limited to the embodiments described above.
  • the control described in each embodiment can be appropriately combined with the control of another embodiment.
  • step S400 it is determined whether or not the anode pressure target value is a pulsation upper limit target value. If it is determined that the target value of the anode pressure is the pulsation upper limit target value, the process proceeds to step S40, and a standby current is passed through the pressure regulating valve 33. On the other hand, if it is determined that the anode pressure target value is not the pulsation upper limit target value, the process proceeds to step S20.
  • step S20 it is determined whether or not the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure calculated in step S10 is a predetermined value or less. If it is determined that the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or less than a predetermined value, the process proceeds to step S40, and a standby current is supplied to the pressure regulating valve 33. On the other hand, if it is determined that the differential pressure is greater than the predetermined value, the process proceeds to step S50 and the standby current is set to zero.

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Abstract

A fuel cell system for supplying an anode gas and a cathode gas to a fuel cell and generating electricity in response to a load, wherein a target anode gas pressure which periodically increases and decreases in the fuel cell is set, and from before a predetermined period in which the target anode gas pressure is increased, a standby electric current is channeled to a pressure regulator valve for regulating the anode gas pressure in the fuel cell on the basis of the target anode gas pressure.

Description

燃料電池システム及び燃料電池システムの制御方法FUEL CELL SYSTEM AND CONTROL METHOD FOR FUEL CELL SYSTEM
　本発明は、燃料電池に供給するアノードガスの圧力を制御する調圧弁の待機電流を制御する技術に関する。 The present invention relates to a technique for controlling a standby current of a pressure regulating valve that controls the pressure of an anode gas supplied to a fuel cell.
　従来、アノードガス非循環型の燃料電池システムにおいて、燃料電池にアノードガスを供給するアノードガス供給通路に設けられた調圧弁を周期的に開閉することによって、燃料電池に供給するアノードガスの圧力を周期的に増減させる脈動運転を行う技術が知られている（ＪＰ２００８－９７９６６Ａ参照）。 Conventionally, in an anode gas non-circulation type fuel cell system, the pressure of the anode gas supplied to the fuel cell is controlled by periodically opening and closing a pressure regulating valve provided in the anode gas supply passage for supplying the anode gas to the fuel cell. A technique for performing pulsation operation that periodically increases or decreases is known (see JP2008-97966A).
　ここで、燃料電池に供給するアノードガスの応答性向上のためには、調圧弁に待機電流を流し続けることが好ましいが、待機電流を流し続けると、その分消費電流が多くなってしまう。ＪＰ２００８－９７９６６Ａには、調圧弁に流す待機電流についての記載は全くない。 Here, in order to improve the responsiveness of the anode gas supplied to the fuel cell, it is preferable to keep the standby current flowing through the pressure regulating valve. However, if the standby current continues to flow, the consumption current increases accordingly. JP 2008-97966A has no description about the standby current flowing through the pressure regulating valve.
　本発明は、調圧弁を周期的に開閉することによってアノードガス圧力を周期的に増減させる燃料電池システムにおいて、燃料電池に供給するアノードガスの応答性を向上させつつ、調圧弁に流す待機電流に起因する消費電流の増加を抑制することができる技術を提供することを目的とする。 In the fuel cell system in which the anode gas pressure is periodically increased / decreased by periodically opening / closing the pressure regulating valve, the present invention improves the responsiveness of the anode gas supplied to the fuel cell while maintaining the standby current flowing through the pressure regulating valve. An object of the present invention is to provide a technique capable of suppressing an increase in current consumption caused by the current consumption.
　一実施形態における燃料電池システムは、周期的に増減する燃料電池内の目標アノードガス圧力を設定し、目標アノードガス圧力を増加させる所定期間前から、目標アノードガス圧力に基づいて燃料電池内のアノードガス圧力を調圧する調圧弁に待機電流を流す。 In one embodiment, a fuel cell system is configured to set a target anode gas pressure in a fuel cell that periodically increases and decreases, and to increase the target anode gas pressure from a predetermined period before the anode in the fuel cell based on the target anode gas pressure. A standby current is passed through a pressure regulating valve that regulates the gas pressure.
　本発明の実施形態、本発明の利点については、添付された図面とともに以下に詳細に説明される。 Embodiments of the present invention and advantages of the present invention will be described below in detail with reference to the accompanying drawings.
図１Ａは、第１の実施形態における燃料電池システムの構成について説明するための図であって、燃料電池の斜視図である。FIG. 1A is a perspective view of the fuel cell for explaining the configuration of the fuel cell system in the first embodiment. 図１Ｂは、第１の実施形態における燃料電池システムの構成について説明するための図であって、図１Ａの燃料電池の１Ｂ－１Ｂ断面図である。FIG. 1B is a diagram for explaining the configuration of the fuel cell system according to the first embodiment, and is a cross-sectional view taken along the line 1B-1B of the fuel cell of FIG. 1A. 図２は、第１の実施形態におけるアノードガス非循環型の燃料電池システムの概略構成図である。FIG. 2 is a schematic configuration diagram of an anode gas non-circulating fuel cell system according to the first embodiment. 図３は、燃料電池システムの運転状態が一定の定常運転時における脈動運転について説明する図である。FIG. 3 is a diagram for explaining pulsation operation during steady operation in which the operation state of the fuel cell system is constant. 図４は、第１の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。FIG. 4 is a flowchart of standby current control performed in the fuel cell system according to the first embodiment. 図５は、アノード圧の目標値の詳細な算出方法を示すフローチャートである。FIG. 5 is a flowchart showing a detailed calculation method of the target value of the anode pressure. 図６は、燃料電池スタックの目標電流（目標出力）と脈動上限目標値および脈動下限目標値との関係を示す図である。FIG. 6 is a diagram showing the relationship between the target current (target output) of the fuel cell stack, the pulsation upper limit target value, and the pulsation lower limit target value. 図７は、第１の実施形態における燃料電池システムにおいて行われる待機電流制御のタイムチャートを示す図である。FIG. 7 is a time chart of standby current control performed in the fuel cell system according to the first embodiment. 図８は、第２の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。FIG. 8 is a flowchart of standby current control performed in the fuel cell system according to the second embodiment. 図９は、燃料電池スタックの出力電流とアノード圧との関係の一例を示す図である。FIG. 9 is a diagram illustrating an example of the relationship between the output current of the fuel cell stack and the anode pressure. 図１０は、第３の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。FIG. 10 is a flowchart of standby current control performed in the fuel cell system according to the third embodiment. 図１１は、第４の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。FIG. 11 is a flowchart of standby current control performed in the fuel cell system according to the fourth embodiment. 図１２は、第４の実施形態における燃料電池システムにおいて行われる待機電流制御のタイムチャートを示す図である。FIG. 12 is a diagram showing a time chart of standby current control performed in the fuel cell system according to the fourth embodiment. 図１３は、第１の実施形態における燃料電池システムにおいて行われる待機電流制御の別のフローチャートである。FIG. 13 is another flowchart of standby current control performed in the fuel cell system according to the first embodiment.
　－第１の実施形態－
　燃料電池は電解質膜をアノード電極（燃料極）とカソード電極（酸化剤極）とで挟み、アノード電極に水素を含有するアノードガス（燃料ガス）、カソード電極に酸素を含有するカソードガス（酸化剤ガス）を供給することによって発電する。アノード電極及びカソード電極の両電極において進行する電極反応は以下の通りである。
　　　アノード電極　：　　２Ｈ2 →４Ｈ+ ＋４ｅ-         　　…(１)
　　　カソード電極　：　　４Ｈ+ ＋４ｅ- ＋Ｏ2 →２Ｈ2Ｏ 　　…(２) -First embodiment-
In a fuel cell, an electrolyte membrane is sandwiched between an anode electrode (fuel electrode) and a cathode electrode (oxidant electrode), an anode gas containing hydrogen in the anode electrode (fuel gas), and a cathode gas containing oxygen in the cathode electrode (oxidant) Electricity is generated by supplying gas. The electrode reaction that proceeds in both the anode electrode and the cathode electrode is as follows.
Anode electrode: 2H 2 → 4H + + 4e − (1)
Cathode electrode: 4H + + 4e − + O 2 → 2H 2 O (2)
　式（１）及び式（２）の電極反応によって燃料電池は１ボルト程度の起電力を生じる。 The fuel cell generates an electromotive force of about 1 volt by the electrode reaction of the formulas (1) and (2).
　図１Ａおよび図１Ｂは、第１の実施形態における燃料電池システムの構成について説明するための図である。図１Ａは、燃料電池１０の斜視図である。図１Ｂは、図１Ａの燃料電池の１Ｂ－１Ｂ断面図である。 1A and 1B are diagrams for explaining the configuration of the fuel cell system according to the first embodiment. FIG. 1A is a perspective view of the fuel cell 10. 1B is a 1B-1B cross-sectional view of the fuel cell of FIG. 1A.
　燃料電池１０は、膜電極接合体（Membrane Electrode Assembly；以下「ＭＥＡ」という）１１の表裏両面に、アノードセパレータ１２とカソードセパレータ１３とが配置されて構成される。 The fuel cell 10 includes an anode separator 12 and a cathode separator 13 arranged on both front and back surfaces of a membrane electrode assembly (hereinafter referred to as “MEA”) 11.
　ＭＥＡ１１は、電解質膜１１１と、アノード電極１１２と、カソード電極１１３と、を備える。ＭＥＡ１１は、電解質膜１１１の一方の面にアノード電極１１２を有し、他方の面にカソード電極１１３を有する。 The MEA 11 includes an electrolyte membrane 111, an anode electrode 112, and a cathode electrode 113. The MEA 11 has an anode electrode 112 on one surface of the electrolyte membrane 111 and a cathode electrode 113 on the other surface.
　電解質膜１１１は、フッ素系樹脂により形成されたプロトン伝導性のイオン交換膜である。電解質膜１１１は、湿潤状態で良好な電気伝導性を示す。 The electrolyte membrane 111 is a proton conductive ion exchange membrane formed of a fluorine-based resin. The electrolyte membrane 111 exhibits good electrical conductivity in a wet state.
　アノード電極１１２は、触媒層１１２ａとガス拡散層１１２ｂとを備える。触媒層１１２ａは、電解質膜１１１と接する。触媒層１１２ａは、白金又は白金等が担持されたカーボンブラック粒子から形成される。ガス拡散層１１２ｂは、触媒層１１２ａの外側（電解質膜１１１の反対側）に設けられ、アノードセパレータ１２と接する。ガス拡散層１１２ｂは、充分なガス拡散性および導電性を有する部材によって形成され、例えば、炭素繊維からなる糸で織成したカーボンクロスで形成される。 The anode electrode 112 includes a catalyst layer 112a and a gas diffusion layer 112b. The catalyst layer 112a is in contact with the electrolyte membrane 111. The catalyst layer 112a is formed of carbon black particles carrying platinum or platinum. The gas diffusion layer 112b is provided outside the catalyst layer 112a (on the opposite side of the electrolyte membrane 111) and is in contact with the anode separator 12. The gas diffusion layer 112b is formed of a member having sufficient gas diffusibility and conductivity, and is formed of, for example, a carbon cloth woven with yarns made of carbon fibers.
　カソード電極１１３もアノード電極１１２と同様に、触媒層１１３ａとガス拡散層１１３ｂとを備える。 Similarly to the anode electrode 112, the cathode electrode 113 includes a catalyst layer 113a and a gas diffusion layer 113b.
　アノードセパレータ１２は、ガス拡散層１１２ｂと接する。アノードセパレータ１２は、ガス拡散層１１２ｂと接する側に、アノード電極１１２にアノードガスを供給するための複数の溝状のアノードガス流路１２１を有する。 The anode separator 12 is in contact with the gas diffusion layer 112b. The anode separator 12 has a plurality of groove-like anode gas passages 121 for supplying anode gas to the anode electrode 112 on the side in contact with the gas diffusion layer 112b.
　カソードセパレータ１３は、ガス拡散層１１３ｂと接する。カソードセパレータ１３は、ガス拡散層１１３ｂと接する側に、カソード電極１１３にカソードガスを供給するための複数の溝状のカソードガス流路１３１を有する。 The cathode separator 13 is in contact with the gas diffusion layer 113b. The cathode separator 13 has a plurality of groove-like cathode gas flow paths 131 for supplying cathode gas to the cathode electrode 113 on the side in contact with the gas diffusion layer 113b.
　アノードガス流路１２１を流れるアノードガスと、カソードガス流路１３１を流れるカソードガスとは、互いに平行に同一方向に流れる。互いに平行に逆方向に流れるようにしても良い。 The anode gas flowing through the anode gas channel 121 and the cathode gas flowing through the cathode gas channel 131 flow in the same direction in parallel with each other. You may make it flow in the opposite direction in parallel with each other.
　このような燃料電池１０を自動車用動力源として使用する場合には、要求される電力が大きいため、数百枚の燃料電池１０を積層した燃料電池スタックとして使用する。そして、燃料電池スタックにアノードガス及びカソードガスを供給する燃料電池システムを構成して、車両駆動用の電力を取り出す。 When such a fuel cell 10 is used as a power source for an automobile, a large amount of electric power is required, so that it is used as a fuel cell stack in which several hundred fuel cells 10 are stacked. Then, a fuel cell system that supplies anode gas and cathode gas to the fuel cell stack is configured, and electric power for driving the vehicle is taken out.
　図２は、第１の実施形態におけるアノードガス非循環型の燃料電池システム１の概略構成図である。 FIG. 2 is a schematic configuration diagram of the anode gas non-circulating fuel cell system 1 according to the first embodiment.
　燃料電池システム１は、燃料電池スタック２と、アノードガス供給装置３と、コントローラ４と、を備える。 The fuel cell system 1 includes a fuel cell stack 2, an anode gas supply device 3, and a controller 4.
　燃料電池スタック２は、複数枚の燃料電池１０を積層したものであり、アノードガス及びカソードガスの供給を受けて発電し、車両の駆動に必要な電力（例えばモータを駆動するために必要な電力）を発電する。 The fuel cell stack 2 is formed by stacking a plurality of fuel cells 10, generates electric power by receiving supply of anode gas and cathode gas, and generates electric power necessary for driving a vehicle (for example, electric power necessary for driving a motor). ).
　燃料電池スタック２にカソードガスを供給・排出するカソードガス給排装置、及び燃料電池スタック２を冷却する冷却装置については、本発明の主要部ではないので、理解を容易にするために図示を省略した。本実施形態ではカソードガスとして空気を使用している。 The cathode gas supply / discharge device for supplying and discharging the cathode gas to / from the fuel cell stack 2 and the cooling device for cooling the fuel cell stack 2 are not the main part of the present invention, and are not shown for the sake of easy understanding. did. In this embodiment, air is used as the cathode gas.
　アノードガス供給装置３は、高圧タンク３１と、アノードガス供給通路３２と、調圧弁３３と、圧力センサ３４と、アノードガス排出通路３５と、バッファタンク３６と、パージ通路３７と、パージ弁３８と、を備える。 The anode gas supply device 3 includes a high-pressure tank 31, an anode gas supply passage 32, a pressure regulating valve 33, a pressure sensor 34, an anode gas discharge passage 35, a buffer tank 36, a purge passage 37, and a purge valve 38. .
　高圧タンク３１は、燃料電池スタック２に供給するアノードガスを高圧状態に保って貯蔵する。 The high pressure tank 31 stores the anode gas supplied to the fuel cell stack 2 in a high pressure state.
　アノードガス供給通路３２は、高圧タンク３１から排出されたアノードガスを燃料電池スタック２に供給するための通路であって、一端部が高圧タンク３１に接続され、他端部が燃料電池スタック２のアノードガス入口孔２１に接続される。 The anode gas supply passage 32 is a passage for supplying the anode gas discharged from the high-pressure tank 31 to the fuel cell stack 2, and has one end connected to the high-pressure tank 31 and the other end of the fuel cell stack 2. Connected to the anode gas inlet hole 21.
　調圧弁３３は、アノードガス供給通路３２に設けられる。調圧弁３３は、高圧タンク３１から排出されたアノードガスを所望の圧力に調節して燃料電池スタック２に供給する。調圧弁３３は、連続的又は段階的に開度を調節することができる電磁弁であり、その開度はコントローラ４によって制御される。コントローラ４は、調圧弁３３に供給する電流の量を制御することによって、調圧弁３３の開度を制御する。 The pressure regulating valve 33 is provided in the anode gas supply passage 32. The pressure regulating valve 33 adjusts the anode gas discharged from the high-pressure tank 31 to a desired pressure and supplies it to the fuel cell stack 2. The pressure regulating valve 33 is an electromagnetic valve whose opening degree can be adjusted continuously or stepwise, and the opening degree is controlled by the controller 4. The controller 4 controls the opening degree of the pressure regulating valve 33 by controlling the amount of current supplied to the pressure regulating valve 33.
　圧力センサ３４は、調圧弁３３よりも下流のアノードガス供給通路３２に設けられる。圧力センサ３４は、調圧弁３３よりも下流のアノードガス供給通路３２を流れるアノードガスの圧力を検出する。本実施形態では、この圧力センサ３４で検出したアノードガスの圧力を、燃料電池スタック内部の各アノードガス流路１２１とバッファタンク３６とを含むアノード系全体の圧力（以下「アノード圧」という。）として代用する。 The pressure sensor 34 is provided in the anode gas supply passage 32 downstream of the pressure regulating valve 33. The pressure sensor 34 detects the pressure of the anode gas flowing through the anode gas supply passage 32 downstream of the pressure regulating valve 33. In the present embodiment, the pressure of the anode gas detected by the pressure sensor 34 is the pressure of the entire anode system including the anode gas flow paths 121 and the buffer tanks 36 inside the fuel cell stack (hereinafter referred to as “anode pressure”). As a substitute.
　アノードガス排出通路３５は、一端部が燃料電池スタック２のアノードガス出口孔２２に接続され、他端部がバッファタンク３６の上部に接続される。アノードガス排出通路３５には、電極反応に使用されなかった余剰のアノードガスと、カソード側からアノードガス流路１２１へとクロスリークしてきた窒素や水蒸気などの不純ガスとの混合ガス（以下「アノードオフガス」という。）が排出される。 The anode gas discharge passage 35 has one end connected to the anode gas outlet hole 22 of the fuel cell stack 2 and the other end connected to the upper portion of the buffer tank 36. The anode gas discharge passage 35 has a mixed gas of excess anode gas that has not been used for the electrode reaction and an impure gas such as nitrogen or water vapor that has cross-leaked from the cathode side to the anode gas passage 121 (hereinafter referred to as “anode”). Off-gas ") is discharged.
　バッファタンク３６は、アノードガス排出通路３５を通って流れてきたアノードオフガスを一旦蓄える。アノードオフガス中の水蒸気の一部は、バッファタンク３６内で凝縮して液水となり、アノードオフガスから分離される。 The buffer tank 36 temporarily stores the anode off gas flowing through the anode gas discharge passage 35. A part of the water vapor in the anode off gas is condensed in the buffer tank 36 to become liquid water and separated from the anode off gas.
　パージ通路３７は、一端部がバッファタンク３６の下部に接続される。パージ通路３７の他端部は、開口端となっている。バッファタンク３６に溜められたアノードオフガス及び液水は、パージ通路３７を通って開口端から外気へ排出される。 One end of the purge passage 37 is connected to the lower part of the buffer tank 36. The other end of the purge passage 37 is an open end. The anode off gas and liquid water stored in the buffer tank 36 are discharged from the opening end to the outside air through the purge passage 37.
　パージ弁３８は、パージ通路３７に設けられる。パージ弁３８は、連続的又は段階的に開度を調節することができる電磁弁であり、その開度はコントローラ４によって制御される。パージ弁３８の開度を調節することで、バッファタンク３６からパージ通路３７を介して外気へ排出するアノードオフガスの量を調節し、バッファタンク３６内のアノードガス濃度が一定以下となるように調節する。これは、バッファタンク３６内のアノードガス濃度が高くなり過ぎると、バッファタンク３６からパージ通路３７を通って外気へ排出されるアノードガス量が多くなり、無駄となるからである。 The purge valve 38 is provided in the purge passage 37. The purge valve 38 is an electromagnetic valve whose opening degree can be adjusted continuously or stepwise, and the opening degree is controlled by the controller 4. By adjusting the opening of the purge valve 38, the amount of anode off-gas discharged from the buffer tank 36 to the outside air via the purge passage 37 is adjusted, and the anode gas concentration in the buffer tank 36 is adjusted to be a certain level or less. To do. This is because if the concentration of the anode gas in the buffer tank 36 becomes too high, the amount of the anode gas discharged from the buffer tank 36 through the purge passage 37 to the outside air increases and is wasted.
　コントローラ４は、中央演算装置（ＣＰＵ）、読み出し専用メモリ（ＲＯＭ）、ランダムアクセスメモリ（ＲＡＭ）及び入出力インタフェース（Ｉ／Ｏインタフェース）を備えたマイクロコンピュータで構成される。 The controller 4 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).
　コントローラ４には、前述した圧力センサ３４の他にも、燃料電池スタック２の出力電流を検出する電流センサ４１や燃料電池スタック２を冷却する冷却水の温度（以下「冷却水温」という。）を検出する温度センサ４２、アクセルペダルの踏み込み量（以下「アクセル操作量」という。）を検出するアクセルストロークセンサ４３などの、燃料電池システム１の運転状態を検出するための信号が入力される。 In addition to the pressure sensor 34 described above, the controller 4 includes a current sensor 41 that detects the output current of the fuel cell stack 2 and a temperature of cooling water that cools the fuel cell stack 2 (hereinafter referred to as “cooling water temperature”). Signals for detecting the operating state of the fuel cell system 1, such as the temperature sensor 42 to detect and the accelerator stroke sensor 43 to detect the amount of depression of the accelerator pedal (hereinafter referred to as "accelerator operation amount") are input.
　コントローラ４は、これらの入力信号に基づいて調圧弁３３を周期的に開閉し、アノード圧を周期的に増減圧させる脈動運転を行うとともに、パージ弁３８の開度を調節してバッファタンク３６から排出するアノードオフガスの流量を調節し、バッファタンク３６内のアノードガス濃度を一定以下に保つ。 The controller 4 periodically opens and closes the pressure regulating valve 33 based on these input signals, performs pulsation operation to periodically increase and decrease the anode pressure, and adjusts the opening degree of the purge valve 38 from the buffer tank 36. The flow rate of the anode off gas to be discharged is adjusted, and the anode gas concentration in the buffer tank 36 is kept below a certain level.
　アノードガス非循環型の燃料電池システム１の場合、調圧弁３３を開いたままにして高圧タンク３１から燃料電池スタック２にアノードガスを供給し続けてしまうと、燃料電池スタック２から排出された未使用のアノードガスを含むアノードオフガスが、バッファタンク３６からパージ通路３７を介して外気へ排出され続けてしまうので無駄となる。 In the case of the anode gas non-circulation type fuel cell system 1, if the anode gas continues to be supplied from the high-pressure tank 31 to the fuel cell stack 2 while the pressure regulating valve 33 is kept open, the fuel cell stack 2 is not discharged. Since the anode off gas including the used anode gas is continuously discharged from the buffer tank 36 through the purge passage 37 to the outside air, it is wasted.
　そこで、本実施形態では調圧弁３３を周期的に開閉し、アノード圧を周期的に増減圧させる脈動運転を行うのである。脈動運転を行うことで、バッファタンク３６に溜めたアノードオフガスを、アノード圧の減圧時に燃料電池スタック２に逆流させることができる。これにより、アノードオフガス中のアノードガスを再利用することができるので、外気へ排出されるアノードガス量を減らすことができ、無駄をなくすことができる。 Therefore, in the present embodiment, the pulsation operation is performed in which the pressure regulating valve 33 is periodically opened and closed to increase and decrease the anode pressure periodically. By performing the pulsation operation, the anode off gas accumulated in the buffer tank 36 can be caused to flow back to the fuel cell stack 2 when the anode pressure is reduced. As a result, the anode gas in the anode off-gas can be reused, so that the amount of the anode gas discharged to the outside air can be reduced and waste can be eliminated.
　図３は、燃料電池システム１の運転状態が一定の定常運転時における脈動運転について説明する図である。 FIG. 3 is a diagram for explaining pulsation operation during steady operation in which the operation state of the fuel cell system 1 is constant.
　図３（Ａ）に示すように、コントローラ４は、燃料電池システム１の運転状態（燃料電池スタックの負荷）に基づいて燃料電池スタック２の目標出力を算出し、目標出力に応じたアノード圧の上限値及び下限値を設定する。そして、設定したアノード圧の上限値及び下限値の間でアノード圧を周期的に増減圧させる。 As shown in FIG. 3A, the controller 4 calculates the target output of the fuel cell stack 2 based on the operating state of the fuel cell system 1 (the load of the fuel cell stack), and sets the anode pressure according to the target output. Set the upper and lower limits. Then, the anode pressure is periodically increased or decreased between the upper limit value and the lower limit value of the set anode pressure.
　具体的には、時刻ｔ１でアノード圧が下限値に達したら、図３（Ｂ）に示すように、少なくともアノード圧を上限値まで増圧させることができる開度まで調圧弁３３を開く。この状態のとき、アノードガスは、高圧タンク３１から燃料電池スタック２に供給され、バッファタンク３６へと排出される。 Specifically, when the anode pressure reaches the lower limit value at time t1, as shown in FIG. 3B, the pressure regulating valve 33 is opened to an opening at which the anode pressure can be increased to at least the upper limit value. In this state, the anode gas is supplied from the high-pressure tank 31 to the fuel cell stack 2 and discharged to the buffer tank 36.
　時刻ｔ２でアノード圧が上限値に達したら、図３（Ｂ）に示すように調圧弁３３を全閉とし、高圧タンク３１から燃料電池スタック２へのアノードガスの供給を停止する。そうすると、上述した（１）の電極反応によって、燃料電池スタック内部のアノードガス流路１２１に残されたアノードガスが時間の経過とともに消費されるので、アノードガスの消費分だけアノード圧が低下する。 When the anode pressure reaches the upper limit at time t2, the pressure regulating valve 33 is fully closed as shown in FIG. 3B, and the supply of anode gas from the high-pressure tank 31 to the fuel cell stack 2 is stopped. Then, since the anode gas left in the anode gas flow path 121 inside the fuel cell stack is consumed over time due to the electrode reaction of (1) described above, the anode pressure is reduced by the consumed amount of the anode gas.
　また、アノードガス流路１２１に残されたアノードガスが消費されると、一時的にバッファタンク３６の圧力がアノードガス流路１２１の圧力よりも高くなるので、バッファタンク３６からアノードガス流路１２１へとアノードオフガスが逆流する。その結果、アノードガス流路１２１に残されたアノードガスと、アノードガス流路１２１に逆流したアノードオフガス中のアノードガスが時間の経過とともに消費され、さらにアノード圧が低下する。 Further, when the anode gas remaining in the anode gas flow path 121 is consumed, the pressure in the buffer tank 36 temporarily becomes higher than the pressure in the anode gas flow path 121, so that the anode gas flow path 121 extends from the buffer tank 36. The anode off-gas flows back into. As a result, the anode gas left in the anode gas channel 121 and the anode gas in the anode off-gas that has flowed back to the anode gas channel 121 are consumed over time, and the anode pressure further decreases.
　時刻ｔ３でアノード圧が下限値に達したら、時刻ｔ１のときと同様に調圧弁３３が開かれる。そして、時刻ｔ４で再びアノード圧が上限値に達したら、調圧弁３３を全閉とする。 When the anode pressure reaches the lower limit at time t3, the pressure regulating valve 33 is opened in the same manner as at time t1. When the anode pressure reaches the upper limit again at time t4, the pressure regulating valve 33 is fully closed.
　ここで、アノードガスの圧力の目標値の増加に応じて、アノードガスの圧力を下限値から上限値へと増加させる際の応答性向上のためには、調圧弁３３が全閉の時にも、調圧弁３３に待機電流を流すことが好ましい。ただし、調圧弁３３の全閉時に常に待機電流を流すと、消費電流が多くなってしまう。 Here, in order to improve the response when increasing the pressure of the anode gas from the lower limit value to the upper limit value in accordance with the increase in the target value of the anode gas pressure, even when the pressure regulating valve 33 is fully closed, It is preferable to pass a standby current through the pressure regulating valve 33. However, if a standby current is always flowed when the pressure regulating valve 33 is fully closed, the current consumption increases.
　従って、第１の実施形態における燃料電池システムでは、アノード圧の昇圧開始の所定時間前から待機電流を流すようにして、アノードガス供給の応答性を向上させつつ、消費電力を抑制する。なお、待機電流とは、調圧弁３３を開かない全閉の状態で流れる電流のことである。 Therefore, in the fuel cell system according to the first embodiment, the standby current is allowed to flow from a predetermined time before the start of increasing the anode pressure, thereby improving the responsiveness of the anode gas supply and suppressing the power consumption. The standby current is a current that flows when the pressure regulating valve 33 is not fully opened.
　図４は、第１の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。ステップＳ１０から始まる処理は、コントローラ４によって行われる。 FIG. 4 is a flowchart of standby current control performed in the fuel cell system according to the first embodiment. The process starting from step S10 is performed by the controller 4.
　ステップＳ１０では、アノード圧の目標値を算出する。アノード圧の目標値の詳細な算出方法を図５に示すフローチャートを用いて説明する。 In step S10, a target value for the anode pressure is calculated. A detailed calculation method of the target value of the anode pressure will be described with reference to the flowchart shown in FIG.
　図５に示すフローチャートのステップＳ１１では、アノード圧を周期的に増減圧させる脈動運転制御時の脈動上限目標値および脈動下限目標値を生成する。 In step S11 of the flowchart shown in FIG. 5, a pulsation upper limit target value and a pulsation lower limit target value during pulsation operation control for periodically increasing and decreasing the anode pressure are generated.
　図６は、燃料電池スタック２の目標電流（目標出力）と脈動上限目標値および脈動下限目標値との関係を示す図である。コントローラ４は、燃料電池システム１の運転状態に基づいて燃料電池スタック２の目標電流（目標出力）を算出し、算出した目標電流（目標出力）と、図６に示す目標電流と脈動目標値との関係のマップとに基づいて、脈動上限目標値および脈動下限目標値を生成する。 FIG. 6 is a diagram showing the relationship between the target current (target output) of the fuel cell stack 2, the pulsation upper limit target value, and the pulsation lower limit target value. The controller 4 calculates the target current (target output) of the fuel cell stack 2 based on the operating state of the fuel cell system 1, and calculates the calculated target current (target output) and the target current and pulsation target value shown in FIG. The pulsation upper limit target value and the pulsation lower limit target value are generated based on the relationship map.
　図５のステップＳ１２では、アノード圧の目標値が圧力センサ３４によって検出されたアノード圧より低いか否かを判定する。アノード圧の目標値の初期値は、例えば、脈動上限目標値とする。アノード圧の目標値が圧力センサ３４によって検出されたアノード圧より低いと判定すると、ステップＳ１３に進み、アノード圧の目標値が圧力センサ３４によって検出されたアノード圧以上であると判定すると、ステップＳ１４に進む。 In step S12 of FIG. 5, it is determined whether or not the target value of the anode pressure is lower than the anode pressure detected by the pressure sensor 34. The initial value of the anode pressure target value is, for example, the pulsation upper limit target value. If it is determined that the target value of the anode pressure is lower than the anode pressure detected by the pressure sensor 34, the process proceeds to step S13, and if it is determined that the target value of the anode pressure is greater than or equal to the anode pressure detected by the pressure sensor 34, step S14 is performed. Proceed to
　ステップＳ１３では、アノード圧の目標値を脈動下限目標値とする。 In step S13, the target value of the anode pressure is set as the pulsation lower limit target value.
　一方、ステップＳ１４では、アノード圧の目標値を脈動上限目標値とする。 On the other hand, in step S14, the anode pressure target value is set as the pulsation upper limit target value.
　図４に示すフローチャートのステップＳ２０では、圧力センサ３４によって検出されたアノード圧と、ステップＳ１０で算出されたアノード圧の目標値との差圧が所定値以下であるか否かを判定する。圧力センサ３４によって検出されたアノード圧とアノード圧の目標値との差圧が所定値以下であると判定すると、ステップＳ４０に進み、調圧弁３３に待機電流を流す。一方、差圧が所定値より大きいと判定すると、ステップＳ３０に進む。 In step S20 of the flowchart shown in FIG. 4, it is determined whether or not the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure calculated in step S10 is a predetermined value or less. If it is determined that the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or less than a predetermined value, the process proceeds to step S40, and a standby current is supplied to the pressure regulating valve 33. On the other hand, if it is determined that the differential pressure is greater than the predetermined value, the process proceeds to step S30.
　ステップＳ３０では、ステップＳ２０で算出されたアノード圧の目標値が圧力センサ３４によって検出されたアノード圧よりも高いか否かを判定する。アノード圧の目標値が圧力センサ３４によって検出されたアノード圧よりも高いと判定すると、ステップＳ４０に進み、調圧弁３３に待機電流を流す。一方、アノード圧の目標値が圧力センサ３４によって検出されたアノード圧以下であると判定すると、ステップＳ５０に進み、待機電流を零とする。 In step S30, it is determined whether or not the target value of the anode pressure calculated in step S20 is higher than the anode pressure detected by the pressure sensor 34. If it is determined that the target value of the anode pressure is higher than the anode pressure detected by the pressure sensor 34, the process proceeds to step S40, and a standby current is caused to flow through the pressure regulating valve 33. On the other hand, if it is determined that the target value of the anode pressure is equal to or lower than the anode pressure detected by the pressure sensor 34, the process proceeds to step S50 and the standby current is set to zero.
　図７は、第１の実施形態における燃料電池システムにおいて行われる待機電流制御のタイムチャートを示す図である。図７では、上から順に、アノード圧の時間変化、待機電流の時間変化、調圧弁３３に供給する電流の時間変化をそれぞれ示している。 FIG. 7 is a diagram showing a time chart of standby current control performed in the fuel cell system according to the first embodiment. In FIG. 7, the temporal change of the anode pressure, the temporal change of the standby current, and the temporal change of the current supplied to the pressure regulating valve 33 are shown in order from the top.
　図７に示す例では、アノード圧の目標値が上限値と下限値とで周期的に交互に切り替わるように制御されており、アノード圧の目標値に追従すべく、実際のアノード圧が変化している。点線で示されているアノード圧（従来例）は、アノード圧の目標値が下限値の場合、すなわち、調圧弁３３を全閉としている場合に、待機電流を零とした場合の例である。 In the example shown in FIG. 7, the target value of the anode pressure is controlled to be alternately switched between the upper limit value and the lower limit value, and the actual anode pressure changes to follow the target value of the anode pressure. ing. The anode pressure (conventional example) indicated by the dotted line is an example in which the standby current is zero when the target value of the anode pressure is the lower limit, that is, when the pressure regulating valve 33 is fully closed.
　本実施形態では、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になると、調圧弁３３に待機電流を流す。図７では、アノード圧の目標値に追従すべく、実際のアノード圧が低下している途中の時刻ｔ１１において、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値と一致して、待機電流を流している。以後、時刻ｔ１３において、アノード圧の目標値が下限値となるまでの間は、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下となっているので、待機電流は流れ続けている。そして、アノード圧の目標値が上限値から下限値へと変化した時刻ｔ１３において、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値より高くなるため、待機電流は零となる。 In the present embodiment, when the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less, a standby current is caused to flow through the pressure regulating valve 33. In FIG. 7, in order to follow the target value of the anode pressure, the difference between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure at time t11 while the actual anode pressure is decreasing is shown. In accordance with the predetermined value, a standby current is flowing. Thereafter, until the target value of the anode pressure reaches the lower limit value at time t13, the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or lower than the predetermined value. The standby current continues to flow. At time t13 when the target value of the anode pressure changes from the upper limit value to the lower limit value, the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes higher than the predetermined value, so that the standby The current becomes zero.
　調圧弁の全閉時に待機電流を常に零とする従来の制御の場合、時刻ｔ１２において、アノード圧の目標値が下限値から上限値へと変化すると、調圧弁３３に供給する電流量を零から増やしていく。この場合、図７に示すように、アノード圧の目標値に対して、実際のアノード圧の追従が遅れる。 In the conventional control in which the standby current is always zero when the pressure regulating valve is fully closed, when the target value of the anode pressure changes from the lower limit value to the upper limit value at time t12, the amount of current supplied to the pressure regulating valve 33 is changed from zero. Increase it. In this case, as shown in FIG. 7, the follow-up of the actual anode pressure is delayed with respect to the target value of the anode pressure.
　これに対して、本実施形態では、アノード圧の目標値が下限値から上限値へと変わる少し前、具体的には、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になると、待機電流を流すので、アノード圧の昇圧時の追従性を向上させることができる。また、アノード圧の目標値を上限値から下限値へと低下させてから、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になるまでの間は、待機電流を零とするので、調圧弁３３の全閉時に待機電流を常に流す場合と比べて、消費電力を低減することができる。 In contrast, in the present embodiment, a short time before the target value of the anode pressure changes from the lower limit value to the upper limit value, specifically, the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure. When the differential pressure becomes a predetermined value or less, the standby current flows, so that the followability when the anode pressure is increased can be improved. Further, after the target value of the anode pressure is decreased from the upper limit value to the lower limit value, the difference between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or lower than a predetermined value. Since the standby current is set to zero, the power consumption can be reduced compared to the case where the standby current is always supplied when the pressure regulating valve 33 is fully closed.
　なお、図４に示すフローチャートでは、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になると、待機電流を流すようにしたが、アノード圧の下限目標値に対する、圧力センサ３４によって検出されたアノード圧の割合（検出アノード圧／アノード圧の下限目標値）が所定の割合以下になると、待機電流を流すようにしてもよい。燃料電池スタック２の高出力領域では、アノード圧の脈動運転制御時における脈動幅が変動するので、アノード圧の下限目標値に対する、圧力センサ３４によって検出されたアノード圧の割合に基づいて、待機電流を流すタイミングを判定する方がより適切なタイミングで待機電流を流すことができる。 In the flowchart shown in FIG. 4, the standby current is made to flow when the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less. When the ratio of the anode pressure detected by the pressure sensor 34 to the value (the detected anode pressure / the lower limit target value of the anode pressure) is equal to or less than a predetermined ratio, the standby current may flow. In the high output region of the fuel cell stack 2, the pulsation width at the time of pulsation operation control of the anode pressure fluctuates, so that the standby current is based on the ratio of the anode pressure detected by the pressure sensor 34 to the lower limit target value of the anode pressure. It is possible to flow the standby current at a more appropriate timing when the timing of flowing the current is determined.
　以上、第１の実施形態における燃料電池システムによれば、アノードガスの圧力を周期的に増減圧させる脈動運転制御時に、アノードガスの圧力の目標値を増加させる所定期間前から調圧弁３３に待機電流を流すので、昇圧時におけるアノード圧の応答性を向上させることができる。また、調圧弁３３の全閉時に常に待機電流を流し続ける場合に比べて、消費電流を抑制することができる。 As described above, according to the fuel cell system of the first embodiment, during the pulsation operation control for periodically increasing or decreasing the pressure of the anode gas, the control valve 33 waits for a predetermined period before the target value of the anode gas pressure is increased. Since the current flows, the responsiveness of the anode pressure at the time of boosting can be improved. In addition, the current consumption can be suppressed as compared with the case where the standby current is always kept flowing when the pressure regulating valve 33 is fully closed.
　特に、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になると、調圧弁３３に待機電流を流すので、昇圧時におけるアノード圧の応答性向上と、待機電流に起因する消費電流の低減を考慮した適切なタイミングで待機電流を流すことができる。 In particular, when the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is less than or equal to a predetermined value, a standby current flows through the pressure regulating valve 33. The standby current can be made to flow at an appropriate timing in consideration of a reduction in current consumption caused by the standby current.
　また、脈動運転制御時におけるアノード圧の下限目標値に対するアノード圧の割合が所定の割合以下になると、調圧弁３３に待機電流を流す方法によれば、昇圧時におけるアノード圧の応答性向上と、待機電流に起因する消費電流の低減を考慮した適切なタイミングで待機電流を流すことができる。特に、アノード圧の脈動幅が一定ではない高出力領域において、より適切なタイミングで待機電流を流すことができる。 Further, when the ratio of the anode pressure to the lower limit target value of the anode pressure at the time of pulsation operation control is equal to or less than a predetermined ratio, according to the method of flowing the standby current to the pressure regulating valve 33, the responsiveness improvement of the anode pressure at the time of pressure increase, The standby current can be made to flow at an appropriate timing in consideration of a reduction in current consumption caused by the standby current. In particular, in a high output region where the pulsation width of the anode pressure is not constant, the standby current can flow at a more appropriate timing.
　なお、燃料電池の出力が所定出力以下であって、脈動運転制御時におけるアノードガスの圧力の下限目標値が所定範囲内にある場合に、図４に示す制御を行うようにしてもよい。すなわち、アノードガス圧力の下限目標値があまり変化しない安定した状態であれば、圧力センサ３４によって検出されたアノード圧と、アノード圧の下限目標値との差圧に基づいて、待機電流を流すタイミングを適確に判断することができるので、より適切なタイミングで待機電流を流すことができる。 Note that the control shown in FIG. 4 may be performed when the output of the fuel cell is equal to or lower than the predetermined output and the lower limit target value of the pressure of the anode gas during the pulsation operation control is within the predetermined range. In other words, if the lower limit target value of the anode gas pressure is stable and does not change so much, the timing of supplying the standby current based on the differential pressure between the anode pressure detected by the pressure sensor 34 and the lower limit target value of the anode pressure. Therefore, the standby current can be supplied at a more appropriate timing.
　－第２の実施形態－
　第２の実施形態における燃料電池システムでは、アノード圧の昇圧時における目標アノード圧に対する実際のアノード圧の応答遅れに基づいて、待機電流を流すタイミングを判定する閾値を変更する。 -Second Embodiment-
In the fuel cell system according to the second embodiment, the threshold value for determining the timing for flowing the standby current is changed based on the response delay of the actual anode pressure with respect to the target anode pressure when the anode pressure is increased.
　図８は、第２の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。ステップＳ１００から始まる処理は、コントローラ４によって行われる。 FIG. 8 is a flowchart of standby current control performed in the fuel cell system according to the second embodiment. The process starting from step S100 is performed by the controller 4.
　ステップＳ１００では、燃料電池スタック２の出力が所定出力以下であるか否かを判定する。燃料電池スタック２の出力が所定出力より大きいと判定するとステップＳ１００に戻り、所定出力以下であると判定すると、ステップＳ１１０に進む。 In step S100, it is determined whether the output of the fuel cell stack 2 is equal to or lower than a predetermined output. If it is determined that the output of the fuel cell stack 2 is greater than the predetermined output, the process returns to step S100. If it is determined that the output is equal to or less than the predetermined output, the process proceeds to step S110.
　ステップＳ１１０では、アノード圧の脈動制御時において、昇圧過程であるか否かを判定する。降圧過程であると判定するとステップＳ１００に戻り、昇圧過程であると判定すると、ステップＳ１２０に進む。 In step S110, it is determined whether or not it is a pressure increasing process during pulsation control of the anode pressure. If it is determined that it is a step-down process, the process returns to step S100, and if it is determined that it is a step-up process, the process proceeds to step S120.
　ステップＳ１２０では、アノード圧の目標値と、圧力センサ３４によって検出されたアノード圧との差圧が所定値以下であるか否かを判定する。差圧が所定値以下であると判定すると、ステップＳ１３０に進み、差圧が所定値より高いと判定すると、ステップＳ１４０に進む。 In step S120, it is determined whether or not the differential pressure between the target value of the anode pressure and the anode pressure detected by the pressure sensor 34 is equal to or less than a predetermined value. If it is determined that the differential pressure is equal to or less than the predetermined value, the process proceeds to step S130, and if it is determined that the differential pressure is higher than the predetermined value, the process proceeds to step S140.
　ステップＳ１３０では、ステップＳ１２０の判定で用いる所定値を小さくする。これにより、所定値を小さくする前と比べて、待機電流を流すタイミングを遅くすることができるので、消費電力を低減することができる。 In step S130, the predetermined value used in the determination in step S120 is decreased. Thereby, compared with the time before making a predetermined value small, since the timing which sends standby electric current can be delayed, power consumption can be reduced.
　一方、ステップＳ１４０では、アノード圧の昇圧時の目標アノード圧に対する実際のアノード圧の応答遅れが大きくなったと判断して、ステップＳ１２０で用いる所定値を前回の所定値、すなわち、小さくする前の所定値に戻す。これにより、待機電流を流すタイミングを早くすることができるので、アノード圧の昇圧時における目標アノード圧に対する実際のアノード圧の応答性を向上させることができる。 On the other hand, in step S140, it is determined that the response delay of the actual anode pressure with respect to the target anode pressure at the time of increasing the anode pressure has increased, and the predetermined value used in step S120 is the previous predetermined value, that is, the predetermined value before being reduced. Return to value. As a result, the timing of flowing the standby current can be advanced, so that the response of the actual anode pressure to the target anode pressure when the anode pressure is increased can be improved.
　図９は、燃料電池スタック２の出力電流とアノード圧との関係の一例を示す図である。図９に示すように、燃料電池スタック２の出力電流が少ない領域では、出力電流の大きさに関係なく、アノード圧の脈動上限圧および脈動下限圧は一定（所定範囲内）である。燃料電池スタック２の出力電流が少ない領域とは、例えば、燃料電池車のアイドル運転時や低速走行時である。 FIG. 9 is a diagram showing an example of the relationship between the output current of the fuel cell stack 2 and the anode pressure. As shown in FIG. 9, in the region where the output current of the fuel cell stack 2 is small, the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant (within a predetermined range) regardless of the magnitude of the output current. The region where the output current of the fuel cell stack 2 is small is, for example, when the fuel cell vehicle is idling or traveling at a low speed.
　本実施形態では、アノード圧の脈動上限圧および脈動下限圧が一定である領域、すなわち、燃料電池スタック２の出力が所定出力以下である領域において、待機電流を流すタイミングを判定する際に用いる所定値を補正する。アノード圧の脈動上限圧および脈動下限圧が一定である安定した状態で、目標アノード圧に対する実アノード圧の追従性を判定するので、所定値を補正するタイミングを正確に判断することができ、所定値を効果的に補正することができる。 In the present embodiment, the predetermined used for determining the timing of flowing the standby current in the region where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant, that is, the region where the output of the fuel cell stack 2 is equal to or lower than the predetermined output. Correct the value. Since the followability of the actual anode pressure with respect to the target anode pressure is determined in a stable state where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant, the timing for correcting the predetermined value can be accurately determined, The value can be corrected effectively.
　なお、図８に示すフローチャートでは、所定値を効果的に補正するため、燃料電池スタック２の出力が所定出力以下である場合に、所定値を補正するものとして説明した。しかし、燃料電池スタック２の出力が所定出力より大きい場合であっても、所定値を補正するようにしてもよい。 In the flowchart shown in FIG. 8, the description has been made assuming that the predetermined value is corrected when the output of the fuel cell stack 2 is equal to or lower than the predetermined output in order to effectively correct the predetermined value. However, the predetermined value may be corrected even when the output of the fuel cell stack 2 is larger than the predetermined output.
　以上、第２の実施形態における燃料電池システムによれば、アノードガスの圧力の目標値とアノードガスの圧力との偏差に基づいて、所定値を補正するので、目標値に対するアノード圧の追従性に基づいて、待機電流を流すタイミングを適切に設定することができる。特に、燃料電池の出力が所定出力以下の場合に、所定値の補正を行うので、アノード圧の脈動上限圧および脈動下限圧が一定である安定した状態で、精度良く所定値の補正を行うことができる。 As described above, according to the fuel cell system of the second embodiment, the predetermined value is corrected based on the deviation between the target value of the anode gas pressure and the pressure of the anode gas. Based on this, it is possible to appropriately set the timing for flowing the standby current. In particular, since the predetermined value is corrected when the output of the fuel cell is equal to or lower than the predetermined output, the predetermined value is accurately corrected in a stable state where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant. Can do.
　なお、アノード圧の下限目標値に対する、圧力センサ３４によって検出されたアノード圧の割合（検出アノード圧／アノード圧の下限目標値）が所定の割合以下になると、待機電流を流す制御を行う場合も、同様の補正を行うことができる。すなわち、アノードガスの圧力の目標値とアノードガスの圧力との偏差が所定値以下であれば、所定の割合を小さくし、偏差が所定値より大きければ、所定の割合を前回の値、すなわち、小さくする前の値に戻す。 Note that when the ratio of the anode pressure detected by the pressure sensor 34 to the lower limit target value of the anode pressure (detected anode pressure / lower limit target value of the anode pressure) is equal to or less than a predetermined ratio, control for flowing a standby current may be performed. The same correction can be performed. That is, if the deviation between the target value of the anode gas pressure and the anode gas pressure is less than or equal to a predetermined value, the predetermined ratio is reduced, and if the deviation is larger than the predetermined value, the predetermined ratio is set to the previous value, that is, Return to the previous value.
　－第３の実施形態－
　第３の実施形態における燃料電池システムでは、アノード圧の昇圧時の目標アノード圧に対する実際のアノード圧の応答遅れに基づいて、待機電流の大きさを変更する。 -Third embodiment-
In the fuel cell system according to the third embodiment, the magnitude of the standby current is changed based on the response delay of the actual anode pressure with respect to the target anode pressure when the anode pressure is increased.
　図１０は、第３の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。図８に示すフローチャートの処理と同一の処理を行うステップについては、同一の符号を付して詳しい説明は省略する。図１０に示すフローチャートの処理もコントローラ４によって行われる。 FIG. 10 is a flowchart of standby current control performed in the fuel cell system according to the third embodiment. Steps for performing the same processes as those in the flowchart shown in FIG. 8 are denoted by the same reference numerals, and detailed description thereof is omitted. The process of the flowchart shown in FIG.
　ステップＳ１２０において、アノード圧の目標値と、圧力センサ３４によって検出されたアノード圧との差圧が所定値以下であると判定すると、ステップＳ２１０に進み、所定値より高いと判定すると、ステップＳ２２０に進む。 If it is determined in step S120 that the differential pressure between the target value of the anode pressure and the anode pressure detected by the pressure sensor 34 is equal to or less than the predetermined value, the process proceeds to step S210, and if it is determined that the pressure is higher than the predetermined value, the process proceeds to step S220. move on.
　ステップＳ２１０では、待機電流の大きさを小さくする。すなわち、アノード圧の昇圧時における目標アノード圧に対する実際のアノード圧の追従性が良いため、待機電流の大きさを小さくすることにより、消費電力を低減する。 In step S210, the standby current is reduced. That is, since the followability of the actual anode pressure with respect to the target anode pressure at the time of increasing the anode pressure is good, the power consumption is reduced by reducing the magnitude of the standby current.
　一方、ステップＳ２２０では、アノード圧の昇圧時の目標アノード圧に対する実際のアノード圧の応答遅れが大きくなったと判断して、待機電流の大きさを前回の大きさ、すなわち、小さくする前の大きさに戻す（大きくする）。これにより、アノード圧の昇圧時における目標アノード圧に対する実際のアノード圧の応答性を向上させることができる。 On the other hand, in step S220, it is determined that the response delay of the actual anode pressure with respect to the target anode pressure at the time of increasing the anode pressure has increased, and the magnitude of the standby current is the previous magnitude, that is, the magnitude before being reduced. Return to (increase). Thereby, the responsiveness of the actual anode pressure with respect to the target anode pressure when the anode pressure is increased can be improved.
　本実施形態では、アノード圧の脈動上限圧および脈動下限圧が一定である領域、すなわち、燃料電池スタック２の出力が所定出力以下である領域において、待機電流の大きさを補正する。アノード圧の脈動上限圧および脈動下限圧が一定である安定した状態で、目標アノード圧に対する実アノード圧の追従性を判定するので、待機電流の大きさを補正するタイミングを正確に判断することができ、待機電流の大きさの補正を効果的に行うことができる。 In this embodiment, the magnitude of the standby current is corrected in a region where the pulsation upper limit pressure and pulsation lower limit pressure of the anode pressure are constant, that is, in a region where the output of the fuel cell stack 2 is equal to or less than a predetermined output. Since the followability of the actual anode pressure with respect to the target anode pressure is determined in a stable state where the pulsation upper limit pressure and the pulsation lower limit pressure of the anode pressure are constant, it is possible to accurately determine the timing for correcting the magnitude of the standby current. Thus, it is possible to effectively correct the standby current.
　なお、図１０に示すフローチャートでは、待機電流の大きさを効果的に補正するため、燃料電池スタック２の出力が所定出力以下である場合に、待機電流の大きさを補正するものとして説明した。しかし、燃料電池スタック２の出力が所定出力より大きい場合であっても、待機電流の大きさを補正するようにしてもよい。 In the flowchart shown in FIG. 10, in order to effectively correct the magnitude of the standby current, it has been described that the magnitude of the standby current is corrected when the output of the fuel cell stack 2 is equal to or less than a predetermined output. However, even when the output of the fuel cell stack 2 is larger than the predetermined output, the magnitude of the standby current may be corrected.
　以上、第３の実施形態における燃料電池システムによれば、アノードガスの圧力の目標値とアノードガスの圧力との偏差に基づいて、待機電流の大きさを補正するので、より適切な大きさの待機電流を流すことができる。 As described above, according to the fuel cell system of the third embodiment, the standby current is corrected based on the deviation between the target value of the anode gas pressure and the anode gas pressure. A standby current can flow.
　なお、アノード圧の下限目標値に対する、圧力センサ３４によって検出されたアノード圧の割合（検出アノード圧／アノード圧の下限目標値）が所定の割合以下になると、待機電流を流す制御を行う場合も、同様の補正を行うことができる。すなわち、アノードガスの圧力の目標値とアノードガスの圧力との偏差が所定値以下であれば、待機電流を小さくし、偏差が所定値より大きければ、待機電流を前回の値、すなわち、小さくする前の値に戻す。 Note that when the ratio of the anode pressure detected by the pressure sensor 34 to the lower limit target value of the anode pressure (detected anode pressure / lower limit target value of the anode pressure) is equal to or less than a predetermined ratio, control for flowing a standby current may be performed. The same correction can be performed. That is, if the deviation between the target value of the anode gas pressure and the anode gas pressure is less than or equal to a predetermined value, the standby current is reduced, and if the deviation is greater than the predetermined value, the standby current is reduced to the previous value, that is, the current. Revert to previous value.
　－第４の実施形態－
　第１の実施形態における燃料電池システムでは、アノード圧の目標値を上限値と下限値とで交互に繰り返す脈動制御時に、アノード圧の目標値が上限値から下限値になると、待機電流を零とし、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になると、待機電流を流すようにした。第４の実施形態における燃料電池システムでは、待機電流が零で、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になる前に、燃料電池スタック２の出力増加指令が生じると、待機電流を流す。 -Fourth Embodiment-
In the fuel cell system according to the first embodiment, when the anode pressure target value changes from the upper limit value to the lower limit value during pulsation control in which the anode pressure target value is alternately repeated at the upper limit value and the lower limit value, the standby current is set to zero. When the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less, a standby current is allowed to flow. In the fuel cell system according to the fourth embodiment, the standby current is zero, and the fuel cell stack 2 before the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less. When an output increase command is generated, a standby current is supplied.
　図１１は、第４の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートである。図４に示すフローチャートの処理と同一の処理を行うステップについては、同一の符号を付して詳しい説明は省略する。図１１に示すフローチャートの処理もコントローラ４によって行われる。 FIG. 11 is a flowchart of standby current control performed in the fuel cell system according to the fourth embodiment. Steps for performing the same processing as the processing in the flowchart shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. The process of the flowchart shown in FIG. 11 is also performed by the controller 4.
　ステップＳ３０の判定を否定すると、ステップＳ３００に進む。ステップＳ３００では、燃料電池スタック２の出力増加指令があるか否かを判定する。例えば、燃料電池車のアクセルが所定開度以上踏み込まれると、燃料電池スタック２の出力増加指令が生じる。燃料電池スタック２の出力増加指令があると判定すると、ステップＳ４０に進み、待機電流を流す。一方、燃料電池スタック２の出力増加指令がない場合には、ステップＳ５０に進み、待機電流を零とする。 If the determination in step S30 is negative, the process proceeds to step S300. In step S300, it is determined whether there is an output increase command for the fuel cell stack 2 or not. For example, when the accelerator of the fuel cell vehicle is depressed more than a predetermined opening, an output increase command for the fuel cell stack 2 is generated. If it is determined that there is an output increase command for the fuel cell stack 2, the process proceeds to step S40, and a standby current is supplied. On the other hand, if there is no output increase command for the fuel cell stack 2, the process proceeds to step S50, and the standby current is set to zero.
　図１２は、第４の実施形態における燃料電池システムにおいて行われる待機電流制御のタイムチャートを示す図である。図１２では、上から順に、燃料電池車のアクセル開度の時間変化、アノード圧の時間変化、待機電流の時間変化、調圧弁３３に供給する電流の時間変化をそれぞれ示している。 FIG. 12 is a diagram showing a time chart of standby current control performed in the fuel cell system according to the fourth embodiment. In FIG. 12, the time change of the accelerator opening of the fuel cell vehicle, the time change of the anode pressure, the time change of the standby current, and the time change of the current supplied to the pressure regulating valve 33 are shown in order from the top.
　図１２に示す例でも、アノード圧の目標値が上限値と下限値とで交互に切り替わるように制御されており、アノード圧の目標値に追従すべく、実際のアノード圧が変化している。ただし、アノード圧の目標値のうち、降圧時の目標値は、上限値から下限値へと矩形パルス状に変化させるが、昇圧時の目標値は、下限値から上限値へと徐々に大きくする。 Also in the example shown in FIG. 12, the target value of the anode pressure is controlled to be alternately switched between the upper limit value and the lower limit value, and the actual anode pressure is changed so as to follow the target value of the anode pressure. However, among the anode pressure target values, the target value at the time of lowering is changed in a rectangular pulse shape from the upper limit value to the lower limit value, but the target value at the time of boosting is gradually increased from the lower limit value to the upper limit value. .
　降圧時の時刻ｔ２１において、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値と一致すると、待機電流を流している。以後、時刻ｔ２２において、アノード圧の目標値が上限値から下限値と変化するまでは、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下となっているので、待機電流を流し続けている。また、アノード圧の目標値が上限値から下限値へと変化した時刻ｔ２２において、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値より高くなるため、待機電流は零となる。 When the pressure difference between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure coincides with a predetermined value at time t21 when the pressure is lowered, a standby current is passed. Thereafter, until the target value of the anode pressure changes from the upper limit value to the lower limit value at time t22, the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes a predetermined value or less. As a result, the standby current continues to flow. Further, at the time t22 when the target value of the anode pressure changes from the upper limit value to the lower limit value, the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure becomes higher than the predetermined value, so that the standby The current becomes zero.
　図１２に示す例では、時刻ｔ２３において、零であったアクセル開度が大きくなり、燃料電池スタック２の出力増加指令が生じるので、待機電流を流している。すなわち、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になっていないが、燃料電池スタック２の出力増加指令が生じたことにより、調圧弁３３に待機電流を流している。 In the example shown in FIG. 12, since the accelerator opening that was zero increases at time t23 and an output increase command for the fuel cell stack 2 is generated, a standby current flows. That is, although the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is not less than a predetermined value, an output increase command from the fuel cell stack 2 is generated, so Standby current is flowing.
　アノード圧の目標値は、アクセル開度が大きくなって、燃料電池スタック２の出力増加指令が生じてから大きくなるので、燃料電池スタック２の出力増加指令が生じてから、アノード圧の目標値が大きくなるまでにはタイムラグが生じる。特に、本実施形態のように、昇圧時のアノード圧の目標値を徐々に大きくする制御システムでは、タイムラグが大きくなる。しかしながら、本実施形態では、圧力センサ３４によって検出されたアノード圧と、アノード圧の目標値との差圧が所定値以下になっていなくても、燃料電池スタック２の出力増加指令が生じたことにより、調圧弁３３に待機電流を流すので、燃料電池スタック２の出力応答性を向上させることができる。 Since the target value of the anode pressure increases after the accelerator opening increases and the output increase command of the fuel cell stack 2 is generated, the target value of the anode pressure is determined after the output increase command of the fuel cell stack 2 is generated. There is a time lag before it grows. In particular, in the control system in which the target value of the anode pressure at the time of boosting is gradually increased as in this embodiment, the time lag is increased. However, in this embodiment, the output increase command of the fuel cell stack 2 is generated even if the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is not less than a predetermined value. As a result, a standby current is caused to flow through the pressure regulating valve 33, so that the output responsiveness of the fuel cell stack 2 can be improved.
　以上、第４の実施形態における燃料電池システムによれば、アノードガスの圧力の目標値を増加させる所定期間前であっても、燃料電池スタック２の出力増加指令があると、調圧弁３３に待機電流を流すので、燃料電池スタック２の出力応答性を向上させることができる。 As described above, according to the fuel cell system of the fourth embodiment, even if the target value of the anode gas pressure is increased before a predetermined period, if there is a command to increase the output of the fuel cell stack 2, the pressure regulating valve 33 is put on standby. Since the current flows, the output responsiveness of the fuel cell stack 2 can be improved.
　なお、燃料電池スタック２の出力増加指令の一例として、燃料電池車のアクセルが所定開度以上踏み込まれた場合を挙げたが、ブレーキが離された場合や、シフトレバーがＰ（パーキング）またはＮ（ニュートラル）の状態から、Ｄ（ドライブ）やＲ（リバース）にシフトした場合等でもよい。 As an example of the output increase command of the fuel cell stack 2, the case where the accelerator of the fuel cell vehicle is depressed more than a predetermined opening is given, but when the brake is released or the shift lever is set to P (parking) or N It may also be the case when shifting from the (neutral) state to D (drive) or R (reverse).
　本発明は、上述した各実施の形態に限定されることはない。例えば、各実施形態で説明した制御は、適宜他の実施形態の制御と組み合わせることができる。 The present invention is not limited to the embodiments described above. For example, the control described in each embodiment can be appropriately combined with the control of another embodiment.
　第１の実施形態における燃料電池システムにおいて行われる待機電流制御のフローチャートを図４に示したが、図１３に示すフローチャートの制御でも同様の効果を得ることができる。図１３に示すフローチャートのうち、図４に示すフローチャートと同一の処理を行うステップについては、同一の符号を付している。以下で、図１３に示すフローチャートの制御を簡単に説明する。 Although the flowchart of the standby current control performed in the fuel cell system in the first embodiment is shown in FIG. 4, the same effect can be obtained by the control of the flowchart shown in FIG. In the flowchart shown in FIG. 13, steps that perform the same processing as in the flowchart shown in FIG. 4 are given the same reference numerals. Hereinafter, the control of the flowchart shown in FIG. 13 will be briefly described.
　ステップＳ１０に続くステップＳ４００では、アノード圧の目標値が脈動上限目標値であるか否かを判定する。アノード圧の目標値が脈動上限目標値であると判定すると、ステップＳ４０に進み、調圧弁３３に待機電流を流す。一方、アノード圧の目標値が脈動上限目標値ではないと判定すると、ステップＳ２０に進む。 In step S400 following step S10, it is determined whether or not the anode pressure target value is a pulsation upper limit target value. If it is determined that the target value of the anode pressure is the pulsation upper limit target value, the process proceeds to step S40, and a standby current is passed through the pressure regulating valve 33. On the other hand, if it is determined that the anode pressure target value is not the pulsation upper limit target value, the process proceeds to step S20.
　ステップＳ２０では、圧力センサ３４によって検出されたアノード圧と、ステップＳ１０で算出されたアノード圧の目標値との差圧が所定値以下であるか否かを判定する。圧力センサ３４によって検出されたアノード圧とアノード圧の目標値との差圧が所定値以下であると判定すると、ステップＳ４０に進み、調圧弁３３に待機電流を流す。一方、差圧が所定値より大きいと判定すると、ステップＳ５０に進み、待機電流を零とする。 In step S20, it is determined whether or not the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure calculated in step S10 is a predetermined value or less. If it is determined that the differential pressure between the anode pressure detected by the pressure sensor 34 and the target value of the anode pressure is equal to or less than a predetermined value, the process proceeds to step S40, and a standby current is supplied to the pressure regulating valve 33. On the other hand, if it is determined that the differential pressure is greater than the predetermined value, the process proceeds to step S50 and the standby current is set to zero.
　なお、燃料電池システムを車両に搭載した例を挙げて説明したが、車両以外の様々なものに適用することもできる。 In addition, although the example which mounted the fuel cell system in the vehicle was given and demonstrated, it can also apply to various things other than a vehicle.
　本願は、２０１２年２月２８日に日本国特許庁に出願された特願２０１２－４１７６６に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2012-41766 filed with the Japan Patent Office on February 28, 2012, the entire contents of which are incorporated herein by reference.

Claims (11)

  1. 　アノードガスおよびカソードガスを燃料電池に供給して負荷に応じて発電する燃料電池システムであって、
    　周期的に増減する燃料電池内の目標アノードガス圧力を設定する目標アノードガス圧力設定手段と、
    　前記目標アノードガス圧力に基づいて燃料電池内のアノードガス圧力を調圧する調圧弁を制御するアノードガス圧力制御手段とを備え、
    　前記アノードガス圧力制御手段は、前記調圧弁に流れる電流を制御することで調圧弁の開度を制御すると共に、前記目標アノードガス圧力を増加させる所定期間前から調圧弁に待機電流を流す待機電流制御手段を備える燃料電池システム。     A fuel cell system that supplies anode gas and cathode gas to a fuel cell to generate electric power according to a load,
    Target anode gas pressure setting means for setting a target anode gas pressure in the fuel cell that periodically increases and decreases;
    An anode gas pressure control means for controlling a pressure regulating valve that regulates the anode gas pressure in the fuel cell based on the target anode gas pressure;
    The anode gas pressure control means controls the current flowing through the pressure regulating valve to control the opening degree of the pressure regulating valve, and wait current to flow the standby current to the pressure regulating valve from a predetermined period before increasing the target anode gas pressure. A fuel cell system comprising control means.
  2. 　請求項１に記載の燃料電池システムにおいて、
    　前記アノードガス圧力を検出するアノードガス圧力検出手段をさらに備え、
    　前記待機電流制御手段は、前記アノードガス圧力と、前記目標アノードガス圧力との差圧が所定値以下になると、前記調圧弁に待機電流を流す、
    燃料電池システム。     The fuel cell system according to claim 1, wherein
    An anode gas pressure detecting means for detecting the anode gas pressure;
    The standby current control means causes a standby current to flow through the pressure regulating valve when a differential pressure between the anode gas pressure and the target anode gas pressure becomes a predetermined value or less.
    Fuel cell system.
  3. 　請求項１に記載の燃料電池システムにおいて、
    　前記アノードガス圧力を検出するアノードガス圧力検出手段をさらに備え、
    　前記待機電流制御手段は、周期的に増減する目標アノードガス圧力の下限値に対する前記アノードガス圧力の割合が所定の割合以下になると、前記調圧弁に待機電流を流す、
    燃料電池システム。     The fuel cell system according to claim 1, wherein
    An anode gas pressure detecting means for detecting the anode gas pressure;
    The standby current control means causes the standby current to flow through the pressure regulating valve when a ratio of the anode gas pressure with respect to a lower limit value of the target anode gas pressure that periodically increases or decreases becomes a predetermined ratio or less.
    Fuel cell system.
  4. 　請求項２に記載の燃料電池システムにおいて、
    　前記目標アノードガス圧力と前記アノードガス圧力との偏差に基づいて、前記所定値を補正する補正手段をさらに備える、
    燃料電池システム。     The fuel cell system according to claim 2, wherein
    A correction means for correcting the predetermined value based on a deviation between the target anode gas pressure and the anode gas pressure;
    Fuel cell system.
  5. 　請求項３に記載の燃料電池システムにおいて、
    　前記目標アノードガス圧力と前記アノードガス圧力との偏差に基づいて、前記所定の割合を補正する補正手段をさらに備える、
    燃料電池システム。     The fuel cell system according to claim 3, wherein
    A correction means for correcting the predetermined ratio based on a deviation between the target anode gas pressure and the anode gas pressure;
    Fuel cell system.
  6. 　請求項２または請求項３に記載の燃料電池システムにおいて、
    　前記目標アノードガス圧力と前記アノードガス圧力との偏差に基づいて、前記調圧弁に流す待機電流の大きさを補正する補正手段をさらに備える、
    燃料電池システム。     The fuel cell system according to claim 2 or 3,
    And a correction means for correcting the magnitude of the standby current flowing through the pressure regulating valve based on a deviation between the target anode gas pressure and the anode gas pressure.
    Fuel cell system.
  7. 　請求項４から請求項６のいずれか一項に記載の燃料電池システムにおいて、
    　前記補正手段は、前記燃料電池の出力が所定出力以下の場合に、前記補正を行う、
    燃料電池システム。     The fuel cell system according to any one of claims 4 to 6,
    The correction means performs the correction when the output of the fuel cell is equal to or lower than a predetermined output.
    Fuel cell system.
  8. 　請求項１から請求項７のいずれか一項に記載の燃料電池システムにおいて、
    　前記待機電流制御手段は、前記目標アノードガス圧力が、周期的に増減する目標アノードガス圧力の下限値になると、前記調圧弁に流す待機電流を零とする、
    燃料電池システム。     In the fuel cell system according to any one of claims 1 to 7,
    When the target anode gas pressure reaches a lower limit value of the target anode gas pressure that periodically increases or decreases, the standby current control means sets the standby current flowing through the pressure regulating valve to zero.
    Fuel cell system.
  9. 　請求項１から請求項８のいずれか一項に記載の燃料電池システムにおいて、
    　前記待機電流制御手段は、前記目標アノードガス圧力を増加させる所定期間前であっても、前記燃料電池の出力増加指令があると、前記調圧弁に待機電流を流す、
    燃料電池システム。     The fuel cell system according to any one of claims 1 to 8,
    The standby current control means allows a standby current to flow through the pressure regulating valve when there is an output increase command of the fuel cell even before a predetermined period of time to increase the target anode gas pressure.
    Fuel cell system.
  10. 　請求項１から請求項９のいずれか一項に記載の燃料電池システムにおいて、
    　前記待機電流制御手段は、前記燃料電池の出力が所定出力以下であって、周期的に増減する目標アノードガス圧力の下限値が所定範囲内にある場合に、前記調圧弁に待機電流を流す制御を行う、
    燃料電池システム。     In the fuel cell system according to any one of claims 1 to 9,
    The standby current control means controls the flow of the standby current to the pressure regulating valve when the output of the fuel cell is equal to or lower than a predetermined output and the lower limit value of the target anode gas pressure that periodically increases or decreases is within a predetermined range. I do,
    Fuel cell system.
  11. 　アノードガスおよびカソードガスを燃料電池に供給して負荷に応じて発電する燃料電池システムの制御方法であって、
    　周期的に増減する燃料電池内の目標アノードガス圧力を設定する工程と、
    　前記目標アノードガス圧力に基づいて燃料電池内のアノードガス圧力を調圧する調圧弁を制御する工程とを備え、
    　前記調圧弁を制御する工程では、前記調圧弁に流れる電流を制御することで調圧弁の開度を制御すると共に、前記目標アノードガス圧力を増加させる所定期間前から調圧弁に待機電流を流す燃料電池システムの制御方法。     A control method of a fuel cell system for supplying anode gas and cathode gas to a fuel cell and generating electric power according to a load,
    Setting a target anode gas pressure in the fuel cell that periodically increases and decreases;
    Controlling a pressure regulating valve for regulating the anode gas pressure in the fuel cell based on the target anode gas pressure,
    In the step of controlling the pressure regulating valve, the opening of the pressure regulating valve is controlled by controlling the current flowing through the pressure regulating valve, and the standby current is supplied to the pressure regulating valve from a predetermined period before the target anode gas pressure is increased. Battery system control method.
PCT/JP2013/054404 2012-02-28 2013-02-21 Fuel cell system and method for controlling fuel cell system WO2013129241A1 (en)

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