WO2013115226A1 - Fuel cell system and control method of fuel cell system - Google Patents

Fuel cell system and control method of fuel cell system Download PDF

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Publication number
WO2013115226A1
WO2013115226A1 PCT/JP2013/052001 JP2013052001W WO2013115226A1 WO 2013115226 A1 WO2013115226 A1 WO 2013115226A1 JP 2013052001 W JP2013052001 W JP 2013052001W WO 2013115226 A1 WO2013115226 A1 WO 2013115226A1
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Prior art keywords
fuel cell
temperature
stack
output
control
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PCT/JP2013/052001
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French (fr)
Japanese (ja)
Inventor
博通 三輪
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日産自動車株式会社
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Publication of WO2013115226A1 publication Critical patent/WO2013115226A1/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
    • H01M8/04298—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
    • H01M8/04701—Temperature
    • H01M8/04708—Temperature of fuel cell reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L1/00—Supplying electric power to auxiliary equipment of vehicles
    • B60L1/003—Supplying electric power to auxiliary equipment of vehicles to auxiliary motors, e.g. for pumps, compressors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L1/00—Supplying electric power to auxiliary equipment of vehicles
    • B60L1/02—Supplying electric power to auxiliary equipment of vehicles to electric heating circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/70—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by fuel cells
    • B60L50/72—Constructional details of fuel cells specially adapted for electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/30—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling fuel cells
    • B60L58/31—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling fuel cells for starting of fuel cells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/30—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling fuel cells
    • B60L58/32—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling fuel cells for controlling the temperature of fuel cells, e.g. by controlling the electric load
    • B60L58/34—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling fuel cells for controlling the temperature of fuel cells, e.g. by controlling the electric load by heating
    • 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
    • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
    • H01M8/04014—Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
    • H01M8/04022—Heating by combustion
    • 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
    • H01M8/04268—Heating of fuel cells during the start-up of the fuel cells
    • 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
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0432—Temperature; Ambient temperature
    • H01M8/04335—Temperature; Ambient temperature of cathode reactants at the inlet or inside the fuel cell
    • 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
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0444—Concentration; Density
    • H01M8/04455—Concentration; Density of cathode reactants at the inlet or inside the fuel cell
    • 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
    • H01M8/04791—Concentration; Density
    • H01M8/04798—Concentration; Density of fuel cell reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B60L2240/36—Temperature of vehicle components or parts
    • 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 fuel cell system and a control method of a fuel cell system, and more particularly to a technology for instantly starting a fuel cell stack to reach a target output required for the system.
  • a combustion burner is installed on the cathode upstream side of the stack, the combustion burner is burned when the stack is started, and the generated combustion gas is supplied to the cathode to raise the temperature of the stack. Then, after the stack reaches the power generation temperature, the stack starts power generation, and when the stack temperature reaches a predetermined value and the generated current or the generated power reaches a predetermined value, the combustion burner is stopped and the rated operation is performed. It is set as a state (for example, refer patent document 1).
  • the conventional fuel cell system disclosed in Patent Document 1 aims to control the timing at which the combustion burner is stopped. Specifically, heating by the combustion burner is stopped before the stack reaches a rated operation state (a state in which a constant output can be obtained), and thereafter, the operation is gradually shifted to the rated operation. Therefore, stopping the combustion burner may delay the temperature rising rate of the stack, and there has been a problem that it is difficult to apply it to an on-vehicle fuel cell that is required to rapidly reach the target output. .
  • the present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a fuel cell system and a control method of the fuel cell system capable of achieving the target output immediately upon start of the fuel cell. I assume.
  • a fuel cell is provided with a reformed gas supplied to an anode and an oxidant supplied to a cathode to generate electricity, and provided on the upstream side of the cathode
  • An oxidizing agent supply unit for supplying an oxidizing agent to the cathode, and an oxidizing agent heating unit provided between the oxidizing agent supply unit and the cathode and heating the oxidizing agent output from the oxidizing agent supply unit;
  • the oxidant heated by the oxidant heating unit is supplied to the cathode to perform control to raise the temperature of the fuel cell, and after the fuel cell reaches the power generation possible temperature, (A)
  • the oxygen excess rate of the oxidant output from the oxidant heating unit is lower than the oxygen excess rate at the target output of the fuel cell until the fuel cell reaches a predetermined target output or target temperature Set
  • a control unit for performing at least one control of the heating control
  • an oxidant supply unit provided on the upstream side of a cathode of a fuel cell and supplying an oxidant to the cathode, the oxidant supply unit, and the cathode
  • a fuel cell system including an oxidant heating unit for heating an oxidant output from the oxidant supply unit, the fuel cell system being heated by the oxidant heating unit when the fuel cell is started.
  • Control to ⁇ comprises the step of performing at least one control of the heating control, among by the oxidizing agent heating unit (c).
  • FIG. 1 is a block diagram showing the configuration of a fuel cell system according to a first embodiment of the present invention.
  • FIG. 2 is a flowchart showing a processing procedure at the time of stack activation of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 3 is a flowchart showing a processing procedure of stack heating control of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 4 is a flowchart showing a processing procedure of stack temperature increase control of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 5 is a flowchart showing a processing procedure of burner and excess oxygen ratio control [1] of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 1 is a block diagram showing the configuration of a fuel cell system according to a first embodiment of the present invention.
  • FIG. 2 is a flowchart showing a processing procedure at the time of stack activation of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 3 is a
  • FIG. 6 is a flow chart showing a processing procedure of burner and excess oxygen ratio control [2] of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 7 is a flowchart showing a processing procedure of excess oxygen ratio control [1] of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 8 is a flowchart showing a processing procedure of excess oxygen ratio control [2] of the fuel cell system according to the first embodiment of the present invention.
  • FIG. 9 is a block diagram showing the configuration of a fuel cell system according to a second embodiment of the present invention.
  • FIG. 10 is a flowchart showing a processing procedure at the time of stack activation of the fuel cell system according to the second embodiment of the present invention.
  • FIG. 11 is a flowchart showing the processing procedure of the second stage stack temperature increase control [1] of the fuel cell system according to the second embodiment of the present invention.
  • FIG. 12 is a flow chart showing a processing procedure of burner and oxygen excess ratio control [3] of the fuel cell system according to the second embodiment of the present invention.
  • FIG. 13 is a flowchart showing the processing procedure of the second stage stack temperature increase control [2] of the fuel cell system according to the second embodiment of the present invention.
  • FIG. 14 is a flowchart showing a processing procedure of excess oxygen ratio control [3] of the fuel cell system according to the second embodiment of the present invention.
  • FIG. 15 is a characteristic diagram showing the relationship between the target output and the energy input at startup of the fuel cell system according to the embodiment of the present invention.
  • FIG. 16 is a characteristic diagram showing the relationship between the current density, the cell voltage and the power density of the fuel cell system according to the embodiment of the present invention.
  • FIG. 17 is a characteristic diagram showing the relationship between the difference value between the target output and the current output of the fuel cell system according to the embodiment of the present invention and the output temperature of the combustion burner.
  • FIG. 18 is a block diagram showing a configuration in which the fuel cell system according to the third embodiment of the present invention is connected to an external load.
  • FIG. 19 is a flowchart showing the processing operation of the fuel cell system according to the third embodiment of the present invention.
  • FIG. 20 is a block diagram showing a configuration in which the fuel cell system according to the fourth embodiment of the present invention is connected to an external load.
  • FIG. 21 is a flowchart showing the processing operation of the fuel cell system according to the fourth embodiment of the present invention.
  • FIG. 22 is a map showing the relationship between the SOC used in the fuel cell system according to the fourth embodiment of the present invention and the required output of the external load.
  • FIG. 23 is a block diagram showing a configuration in which the fuel cell system according to the fifth embodiment of the present invention is connected to an external load.
  • FIG. 24 is a flowchart showing the processing operation of the fuel cell system according to the fifth embodiment of the present invention.
  • FIG. 25 is a characteristic diagram showing time-series data of a target temperature and a target output used in a fuel cell system according to a fifth embodiment of the present invention.
  • FIG. 26 is a map showing the relationship between the SOC and the output used in the fuel cell system according to the fifth embodiment of the present invention.
  • FIG. 1 is a block diagram showing the configuration of a fuel cell system 100 according to the present embodiment.
  • the fuel cell system 100 includes a fuel cell stack 11 (hereinafter, abbreviated as stack 11), an air blower (oxidizer supply unit) 12, a heat exchanger 13, a first fuel pump 14, and a heat exchange type.
  • a pre-reformer 15 and an evaporator 25 are provided.
  • the stack 11 includes a cathode 11a and an anode 11b.
  • the air blower 12 supplies air (oxidant) to the cathode 11a.
  • the heat exchanger 13 heats the air delivered from the air blower 12.
  • the first fuel pump 14 supplies fuel such as hydrocarbon fuel to the anode 11 b of the stack 11.
  • the evaporator 25 vaporizes the fuel delivered from the first fuel pump 14.
  • the heat exchange type pre-reforming apparatus 15 reforms the fuel vaporized by the evaporator 25 and supplies the reformed fuel to the anode 11 b.
  • the heat exchange type pre-reformer 15 includes a pre-reformer 16 and a combustor 17 that heats the pre-reformer 16.
  • a part of air sent from the air blower 12 and an anode off gas (a gas discharged from the anode 11 b) are supplied to the combustor 17 and burned to heat the pre-reformer 16.
  • the output side of the combustor 17 is connected to the high temperature side of the heat exchanger 13.
  • the exhaust gas output from the combustor 17 is used as a heating gas for the heat exchanger 13.
  • a portion of the air delivered from the air blower 12, the fuel delivered from the first fuel pump 14 and the fuel vaporized in the evaporator 25, and a portion of the anode off gas are supplied to the pre-reformer 16 and the combustor
  • the heat generated at 17 reforms the fuel, and the reformed fuel is supplied to the anode 11 b of the stack 11.
  • the output side of the air blower 12 is connected to the low temperature side of the heat exchanger 13.
  • the outlet on the high temperature side of the heat exchanger 13 is connected to a combustion burner (oxidant heater) 21 for heating the cathode 11 a when the stack 11 is started.
  • the combustion burners 21 are connected to the second fuel pump 22, and fuel is supplied from the second fuel pump 22. Therefore, the air heated by the heat exchanger 13 and the fuel delivered from the second fuel pump 22 are supplied to the combustion burner 21 and burnt. Then, the combustion gas is supplied to the cathode 11 a of the stack 11.
  • An anode off gas circulator 23 is provided on the output side of the anode 11 b.
  • the anode off gas circulator 23 branches the anode off gas output from the anode 11 b into two systems. Specifically, the anode off gas circulator 23 supplies the anode off gas branched to one to the pre-reformer 16 and supplies the anode off gas branched to the other to the combustor 17.
  • Flow control devices 19 and 20 are provided between the air blower 12 and the heat exchange type pre-reforming apparatus 15.
  • the flow control devices 19 and 20 adjust the flow rates of the air supplied to the pre-reformer 16 and the air flow supplied to the combustor 17 so as to be desired flow rates.
  • the stack 11 is provided with an inlet temperature sensor 41a that measures the temperature near the inlet, an outlet temperature sensor 41b that measures the temperature near the outlet, and a current / voltage sensor 42 that detects the output current and voltage of the stack 11. ing.
  • the fuel cell system 100 includes a control unit (control unit) 31 that collectively controls the entire system.
  • the control unit 31 measures and calculates the stack temperature (for example, the average value of the inlet temperature and the outlet temperature) measured by the inlet temperature sensor 41a and the outlet temperature sensor 41b provided in the stack 11, and the current / voltage sensor 42 Based on the generated power output, a process of controlling the amount of fuel supplied by the second fuel pump 22 and the amount of air by the air blower 12 is performed.
  • the control unit 31 can be configured as, for example, an integrated computer including storage units such as a central processing unit (CPU), a RAM, a ROM, and a hard disk.
  • FIG. 2 is a flowchart showing the entire processing procedure of the temperature raising operation of the stack at the time of startup of the fuel cell system 100.
  • step S11 the control unit 31 determines whether to activate the stack 11.
  • step S12 the control unit 31 determines whether the heating of the stack 11 by the combustion burner 21 has ended. If the heating of the stack 11 is not completed (NO in step S12), the control unit 31 continues the heating control of the stack 11 by the combustion burner 21 in step S13. Details of the stack heating control will be described later with reference to the flowchart shown in FIG. Thereafter, the process proceeds to step S14.
  • step S14 the control unit 31 determines whether the stack temperature increase control has ended. If the stack temperature increase control has not ended (NO in step S14), the control unit 31 performs stack temperature increase control in step S15. Details of the stack temperature increase control will be described later with reference to the flowchart shown in FIG. Thereafter, the process returns. Note that “stack heating control” is control for raising the temperature of the stack 11 to a temperature at which power can be generated, and “stack heating control” means that the temperature of the stack 11 raised to the temperature at which power can be generated is further raised to generate power. It is control to raise to target temperature.
  • step S21 the control unit 31 activates the air blower 12 to supply air to the combustion burners 21.
  • step S ⁇ b> 22 the control unit 31 activates the combustion burner 21 to burn the fuel supplied from the second fuel pump 22 and the air supplied from the air blower 12. Then, the combustion gas generated by the combustion burner 21 is supplied into the cathode 11 a of the stack 11 to raise the temperature of the cathode 11 a.
  • step S23 the control unit 31 controls the amount of air supplied from the air blower 12 into the cathode 11a.
  • the control unit 31 controls the amount of fuel supplied to the combustion burners 21.
  • the control unit 31 controls the amount of combustion gas supplied from the combustion burner 21 to the cathode 11 a and the outlet temperature of the combustion burner 21 to be in predetermined states.
  • step S25 the control unit 31 detects the temperature of the stack 11 (for example, the average value of the inlet temperature and the outlet temperature) by the inlet temperature sensor 41a and the outlet temperature sensor 41b.
  • step S26 the control unit 31 determines whether the temperature of the stack 11 has reached a predetermined temperature (the temperature at which the stack 11 can generate power). If the temperature of the stack 11 has not reached the predetermined temperature (NO in step S26), the process returns to step S23. If the temperature of the stack 11 has reached the predetermined temperature (YES in step S26), the control unit 31 ends the heating by the combustion burner 21 in step S27, and turns on the flag of the heating end determination. Thus, the control unit 31 can raise the temperature of the stack 11 to the power generation possible temperature.
  • a predetermined temperature the temperature at which the stack 11 can generate power.
  • step S31 shown in FIG. 4 the control unit 31 detects the temperature of the stack 11 and the output of the stack 11 (calculated from the power and current).
  • step S32 the control unit 31 determines whether the output of the stack 11 has reached the target output.
  • step S35 the control unit 31 controls the current value such that the generated output of the stack 11 becomes the target output.
  • step S36 the control unit 31 turns on a flag indicating that the output of the stack 11 has reached the target output. Thereafter, the process proceeds to step S37.
  • step S33 the control unit 31 reads the cell voltage target value stored in a memory (not shown) or the like.
  • step S34 the control unit 31 controls the cell voltage such that the cell voltage target value is obtained.
  • the control unit 31 controls the cell voltage to be a predetermined value, and controls the output of the stack 11 to be a target output as the temperature of the stack 11 rises.
  • the stack 11 is a structure in which a plurality of cells are stacked.
  • the cell voltage is the output voltage of each cell. It is desirable to control the cell voltage to about 0.5V. Control of the cell voltage will be described later with reference to FIG. Thereafter, the process proceeds to step S37.
  • step S37 the control unit 31 determines whether the target output of the stack 11 is larger than a predetermined output set in advance. Specifically, the control unit 31 determines whether the target output of the stack 11 is larger than a predetermined value X1 set in advance. As shown in the characteristic curve of FIG. 15, the relationship between the target output of the stack 11 and the energy input to the stack 11 differs between the on time and the off time of the combustion burner 21.
  • Curve Q1 in FIG. 15 shows the on-time characteristics of the combustion burner 21, and curve Q2 shows the off-time characteristics of the combustion burner 21. It can be seen from FIG. 15 that the input energy can be reduced by turning on the combustion burner 21 when the target output of the stack 11 exceeds the predetermined value X1. Therefore, in the fuel cell system 100, when the target output of the stack 11 exceeds the predetermined value X1, the stack burner 11 is heated to the target temperature by operating the combustion burners 21. On the other hand, when the target output of the stack 11 falls below the predetermined value X1, the temperature of the stack 11 is raised without operating the combustion burners 21.
  • the “target temperature” is a temperature when the stack 11 is in steady operation, and is a temperature higher than the power generation possible temperature.
  • step S38 the control unit 31 determines whether the temperature of the stack 11 has reached the target temperature. If the temperature of the stack 11 has not reached the target temperature (NO in step S38), the controller 31 executes burner and oxygen excess ratio control [1] in step S39. The details of the burner and the excess oxygen ratio control [1] will be described later with reference to the flowchart shown in FIG. On the other hand, when the temperature of the stack 11 has reached the target temperature (YES in step S38), the control unit 31 executes burner and oxygen excess ratio control [2] in step S40. The details of the burner and the excess oxygen ratio control [2] will be described later with reference to the flowchart shown in FIG.
  • step S37 When it is determined in step S37 that the target output of the stack 11 is less than or equal to the predetermined value X1 (NO in step S37), the controller 31 determines that the temperature of the stack 11 reaches the target temperature in step S41. Determine if you If the temperature of the stack 11 has not reached the target temperature (NO in step S41), the control unit 31 executes excess oxygen ratio control [1] in step S42. The details of the excess oxygen ratio control [1] will be described later with reference to the flowchart shown in FIG. On the other hand, when the temperature of the stack 11 has reached the target temperature (YES in step S41), in step S43, the control unit 31 executes excess oxygen ratio control [2]. The details of the excess oxygen ratio control [2] will be described later with reference to the flowchart shown in FIG.
  • the control unit 31 controls the stack 11 in step S44. It is determined whether the temperature has reached the target temperature. If the temperature of the stack 11 has reached the target temperature (YES in step S44), in step S45, the control unit 31 turns on a target temperature attainment determination flag indicating that the temperature of the stack 11 has reached the target temperature. Do.
  • step S46 the control unit 31 determines whether the temperature and output of the stack 11 have reached the target temperature and the target output. If the temperature and the output of the stack 11 have not reached the target temperature and the target output (NO in step S46), the process ends. On the other hand, if the temperature and the output of stack 11 have reached the target temperature and the target output (YES in step S46), control unit 31 ends the stack temperature increase control in step S47, and the stack temperature increase control end determination Turn on the flag.
  • the target temperature arrival flag is turned on in the process of step S45 and the stack temperature increase control end flag is turned on in the process of step S47, the stack temperature increase control shown in step S15 of FIG. 2 is completed.
  • FIG. 16 shows the relationship between current density (A / cm 2), cell voltage (V) and output density (W / cm 2).
  • the symbol V1 indicates the output voltage at the temperature T1
  • the symbol V2 indicates the output voltage at the temperature T2 (> T1)
  • the symbol V3 indicates the output voltage at the temperature T3 (> T2).
  • the symbol W1 indicates the output density (W / cm 2) at the temperature T1
  • the symbol W2 indicates the output density at the temperature T2
  • the symbol W3 indicates the output density at the temperature T3.
  • the output power per unit area that is, the output density has a peak value. doing. Therefore, in the process shown in step S34 of FIG. 4, by controlling the cell voltage to about 0.5 (V), the output power can be increased to obtain a large amount of heat generation. That is, by controlling the cell voltage to about 0.5 (V), the temperature increase effect of the stack 11 can be improved.
  • step S51 the control unit 31 reads a target oxygen excess rate.
  • a target excess oxygen rate e.g., 1.3 or the like
  • the target oxygen excess rate stored in the memory or the like is set to a value lower than the target oxygen excess rate in the normal operation. Therefore, if the target oxygen excess rate is used to control the amount of oxygen supplied to the cathode 11a, less oxygen (air) will be supplied than during normal operation, and the temperature of the stack 11 will rise. .
  • step S52 the control unit 31 reads the target outlet temperature of the combustion burner 21 and the amount of supplied air.
  • the target outlet temperature of the combustion burner 21 stored in advance in a memory (not shown) or the like is read and acquired.
  • step S ⁇ b> 53 the control unit 31 detects the output current of the stack 11 by the current / voltage sensor 42 provided on the stack 11.
  • step S54 the control unit 31 calculates the minimum required oxygen amount according to the output current detected in the process of step S53. Specifically, a value obtained by multiplying the minimum value of the amount of oxygen necessary to obtain the output current by the excess oxygen ratio acquired in the process of step S51 is obtained as the required oxygen amount.
  • step S55 based on the target outlet temperature of the combustion burner 21 obtained in the process of step S52, the control unit 31 calculates the required fuel amount of the combustion burner 21 required to achieve this temperature. That is, if the required oxygen amount of the stack 11 and the target outlet temperature of the combustion burner 21 are determined, the required fuel amount can be obtained.
  • step S56 the control unit 31 calculates the amount of air to be delivered from the air blower 12 based on the required oxygen amount obtained in the process of step S54 and the required fuel amount obtained in the process of step S55 (in this case, In consideration of the amount of oxygen consumed by the combustion in the combustion burner 21, the amount of air is calculated so that the excess oxygen ratio at the outlet of the combustion burner 21 becomes the required oxygen amount set in the process of step S54). That is, the amount of oxygen in the gas discharged after the air delivered from the air blower 12 is supplied to the combustion burner 21 and burned by the combustion burner 21 becomes the required oxygen amount obtained in the process of step S54. , Calculate the required cathode air amount.
  • step S57 the control unit 31 compares the amount of air obtained in the process of step S56 with the amount of supplied air (actually measured value) read in step S52 so that the amount of supplied air becomes the required amount of cathode air.
  • the amount of air supplied to the cathode 11a is set, and further, the amount of fuel supplied to the combustion burner 21 is set in step S58, and the air blower 12 and the second fuel pump are set so as to have these amounts of air and fuel.
  • the stack 11 can be heated by controlling the amount of air supplied to the cathode 11 a and the amount of fuel supplied to the combustion burner 21 based on the excess oxygen ratio. That is, by supplying the combustion gas of the combustion burner 21 and setting the oxygen excess rate lower than that during normal operation, the temperature of the stack 11 can be rapidly raised.
  • step S40 of FIG. 4 the detailed processing procedure of the burner and the excess oxygen ratio control [2] shown in step S40 of FIG. 4 will be described with reference to the flowchart shown in FIG.
  • the temperature difference ⁇ T outlet temperature ⁇ inlet temperature
  • the combustion burner 21 and the excess oxygen ratio are controlled so that the temperature of the stack 11 maintains the target temperature.
  • step S61 the control unit 31 detects the temperature difference ⁇ T between the outlet temperature and the inlet temperature of the stack 11 or the outlet temperature of the cathode 11a.
  • step S62 the control unit 31 reads the target outlet temperature of the combustion burner 21.
  • the target outlet temperature stored in the memory or the like is read and acquired.
  • step S63 the control unit 31 calculates the amount of excess oxygen combustion gas supplied to the cathode 11a, that is, the flow amount of excess oxygen gas discharged after the combustion with the combustion burner 21 (hereinafter referred to as the amount of supply gas). Then, the control unit 31 performs control such that the amount of gas supplied to the cathode 11 a becomes the amount of supplied gas in the subsequent processing.
  • the supply gas amount is increased by a predetermined amount if ⁇ T> 0, and the supply gas amount is decreased by a predetermined amount if ⁇ T ⁇ 0.
  • the temperature difference .DELTA.T is controlled so as to approach zero by performing the control.
  • the outlet temperature is detected in step S61, if (outlet temperature)> (target temperature), the amount of supplied gas is increased by a predetermined amount, and if (outlet temperature) ⁇ (target temperature) the supplied gas By reducing the amount by a predetermined amount, the temperature of the stack 11 is controlled to be the target temperature.
  • step S64 the control unit 31 calculates the required cathode air amount to be sent from the air blower 12 based on the supply gas amount obtained in the process of step S63. That is, the air blower 12 is supplied with the air delivered from the air blower 12 and supplied to the combustion burner 21 so that the amount of gas discharged after burning by the combustion burner 21 becomes the amount of supplied gas obtained in the process of step S63. 12 calculates the amount of air to be delivered.
  • step S65 based on the target outlet temperature of the combustion burner 21 obtained in the process of step S62, the control unit 31 calculates the required fuel amount of the combustion burner 21 required to achieve this temperature.
  • step S66 the control unit 31 sets the amount of air obtained in the process of step S64 as the amount of air supplied to the cathode 11a, and further sets the amount of fuel supplied to the combustion burner 21 in step S67.
  • the air blower 12 and the second fuel pump 22 are controlled so that the amount of air and the amount of fuel become as follows.
  • the temperature of the stack 11 can be maintained at the target temperature by controlling the amount of air supplied to the cathode 11a and the amount of fuel supplied to the combustion burner 21 based on the oxygen excess rate.
  • step S71 the control unit 31 reads a target oxygen excess rate.
  • the target oxygen excess rate stored in advance in a memory (not shown) or the like is read and acquired.
  • the oxygen excess rate is set to a lower value than the oxygen excess rate during normal operation of the stack 11.
  • step S ⁇ b> 72 the control unit 31 detects the output current of the stack 11 by the current / voltage sensor 42 provided in the stack 11.
  • step S73 the control unit 31 calculates the minimum required oxygen amount according to the output current detected in the process of step S72. Specifically, a value obtained by multiplying the minimum value of the amount of oxygen necessary to obtain the output current by the excess oxygen ratio acquired in the process of step S71 is obtained as the required oxygen amount.
  • step S74 the control unit 31 calculates the amount of air to be delivered from the air blower 12 based on the required oxygen amount obtained in the process of step S73. That is, the amount of air required to supply the required oxygen amount to the cathode 11a is calculated.
  • step S75 the control unit 31 sets the amount of air obtained in the process of step S74 as the amount of air supplied to the cathode 11a, and controls the air blower 12 to become this air.
  • the stack 11 can be heated by controlling the amount of air supplied to the cathode 11 a based on the oxygen excess rate.
  • the target excess oxygen ratio is set to be lower than the excess oxygen ratio in the normal operation, the amount of oxygen (the amount of air) supplied to the cathode 11a becomes smaller than in the normal operation, and the cooling effect is reduced.
  • the temperature can be reduced to raise the temperature of the stack 11.
  • step S43 of FIG. 4 the temperature difference between the outlet and the inlet of the stack 11 or the outlet temperature of the stack 11 Based on the control of the excess oxygen rate so that the temperature of the stack 11 maintains the target temperature.
  • step S81 the control unit 31 detects a temperature difference ⁇ T between the outlet temperature of the stack 11 and the inlet temperature, or the outlet temperature of the cathode 11a.
  • step S82 the control unit 31 calculates the required cathode air amount to be delivered from the air blower 12. Specifically, if the temperature difference ⁇ T is detected in the process of step S81, the supplied air amount is increased by a predetermined amount if ⁇ T> 0, and the supplied air amount is decreased by a predetermined amount if ⁇ T ⁇ 0.
  • the temperature difference .DELTA.T is controlled so as to approach zero by performing the control.
  • the outlet temperature is detected in step S81, if (outlet temperature)> (target temperature), the supplied air amount is increased by a predetermined amount, and if (outlet temperature) ⁇ (target temperature), the supplied air By reducing the amount by a predetermined amount, the temperature of the stack 11 is controlled to approach the target temperature.
  • step S83 the control unit 31 sets the amount of air obtained in the process of step S82 as the amount of air supplied to the cathode 11a, and controls the air blower 12 to achieve this amount of air.
  • the stack 11 can be maintained at the target temperature by controlling the amount of air supplied to the cathode 11a based on the oxygen excess rate.
  • the fuel cell system 100 at least one of the cell voltage of the stack 11, the excess oxygen ratio of the gas supplied to the cathode 11a, and the combustion gas output from the combustion burner 21.
  • the stack 11 raised to the power generation possible temperature is raised to the target temperature necessary for the operation at the target output. Therefore, the temperature rise of the stack 11 is promoted, and the target temperature or the target output can be quickly reached. Therefore, it is extremely useful in the case of a stack where quick responsiveness is required, for example, when mounted on a vehicle.
  • the amount of energy required to raise the temperature can be reduced.
  • the stack 11 is heated without operating the combustion burners 21. That is, at least one of the oxygen excess rate control of the gas supplied to the cathode 11a and the cell voltage control of the stack 11 is controlled to raise the temperature of the fuel cell to the target temperature with the combustion burner 21 stopped. . Therefore, the amount of energy consumed can be reduced.
  • the voltage value at which the fuel cell output reaches a peak is controlled to be a constant ratio, for example, the cell voltage to be around 0.5 (V).
  • the stack 11 can be efficiently heated to the target temperature.
  • FIG. 9 is a block diagram showing a configuration of a fuel cell system 100a according to the present embodiment.
  • the fuel cell system 100a differs from the configuration of the first embodiment in the following points: (1) Second stage having a cathode 32a and an anode 32b at the rear stage of the stack 11 (first stage stack) The stack 32 is provided; (2) in a flow path connecting the outlet of the cathode 11 a of the first stage stack (first fuel cell) 11 and the inlet of the cathode 32 a of the second stage stack (second fuel cell) 32
  • the cooling air introduction passage (bypass passage) 33 is connected, and a part of the air delivered from the air blower 12 via the cooling air introduction passage 33 is introduced into the cathode 32 a.
  • the cooling air introduction passage 33 is provided with a cooling air flow control device 34 for adjusting the amount of air introduced into the cathode 32a.
  • the second stage stack 32 is provided with an inlet temperature sensor 51a for measuring the temperature on the inlet side, an outlet temperature sensor 51b for measuring the temperature on the outlet side, and a current / voltage sensor 52 for measuring the output current and voltage. It is done.
  • the other configuration is the same as the configuration shown in FIG. 1, so the same reference numerals are given and the description of the configuration is omitted.
  • FIG. 10 is a flowchart showing the entire processing procedure of the temperature raising operation of the stack at the time of startup of the fuel cell system 100a.
  • step S101 the control unit 31 determines whether to activate the first stage stack 11.
  • the control unit 31 determines in step S102 whether the heating of the first stage stack 11 by the combustion burner 21 is finished. If the heating of the first stage stack 11 is not completed (NO in step S102), the control unit 31 continues the heating control of the first stage stack 11 by the combustion burner 21 in step S103.
  • the details of the stack heating control are the same processing as the flowchart shown in FIG. Thereafter, the process proceeds to step S104.
  • step S104 the control unit 31 determines whether the temperature increase control of the first-stage stack 11 has ended. If the temperature increase control of the first stage stack 11 is not completed (NO in step S104), the control unit 31 performs the temperature increase control of the first stage stack 11 in step S105.
  • the temperature increase control of the first-stage stack 11 is the same processing as the flowchart shown in FIG. Thereafter, the process proceeds to step S106.
  • step S106 the control unit 31 determines whether the first temperature increase control of the second stack 32 is necessary.
  • the first temperature raising control is control for raising the temperature of the second-stage stack 32 until it reaches the power generation possible temperature. If the second stage stack 32 has not reached the power generation possible temperature and the first temperature increase control of the second stage stack 32 is required (YES in step S106), the control unit 31 determines in step S107 that The first temperature increase control of the second stage stack 32 is performed. The details of the first temperature increase control will be described later with reference to FIG.
  • the control unit 31 is performed in step S108. It is determined whether or not the second temperature increase control of the second stage stack is necessary.
  • the second temperature increase control is control to further increase the temperature to the temperature during normal operation after the second-stage stack 32 reaches the power generation possible temperature. If the second stage stack 32 has not reached the temperature at the time of normal operation and the second temperature increase control of the second stage stack 32 is required (YES in step S108), the controller 31 in step S109. Executes the second temperature increase control of the second stage stack 32. The details of the second temperature increase control will be described later with reference to FIG.
  • step S111 the control unit 31 reads a target output (total target output of the first stack 11 and the second stack 32) stored in a memory (not shown) or the like.
  • step S112 the control unit 31 determines whether or not it is possible to obtain the target output by the operation of only the first-stage stack 11. If it is possible to obtain the target output by the operation of only the first stage stack 11 (YES in step S112), the control unit 31 determines the first temperature increase control unnecessary flag of the second stage stack 32 in step S116. Turn on.
  • the controller 31 controls the inlet temperature sensor 51a provided in the second-stage stack 32 in step S113.
  • the outlet temperature sensor 51b detects the temperature of the second stage stack 32 (for example, the average value of the inlet temperature and the outlet temperature).
  • step S114 the control unit 31 determines whether it is necessary to raise the temperature of the second stack 32. Specifically, when the temperature of the second stack 32 has reached the power generation possible temperature in the process of step S113, the first temperature increase control is unnecessary, and the process proceeds to step S116. On the other hand, when the temperature of the second stack 32 has not reached the power generation possible temperature in the process of step S113, it is necessary to perform the first temperature increase control, so the process proceeds to step S115.
  • step S115 the control unit 31 executes burner and oxygen excess ratio control [3]. Details of the burner and the excess oxygen ratio control [3] will be described later with reference to the flowchart shown in FIG.
  • step S121 the control unit 31 sets the temperature difference .DELTA.T between the inlet temperature measured by the inlet temperature sensor 41a provided in the first stage stack 11 and the outlet temperature measured by the outlet temperature sensor 41b (outlet temperature- The inlet temperature) or the outlet temperature of the cathode 11a is detected.
  • step S122 the control unit 31 calculates these difference values from the relationship between the target output and the current output (current output) of the first stage stack 11.
  • step S123 the control unit 31 determines whether it is necessary to activate the combustion burner 21 based on the difference value obtained in the process of step S122. Specifically, the control unit 31 determines that it is necessary to start the combustion burner 21 when the difference value is larger than a predetermined value. If it is necessary to activate the combustion burners 21 (YES in step S123), the process proceeds to step S124. On the other hand, when it is not necessary to start the combustion burner 21 (NO in step S123), the process proceeds to step S130.
  • step S124 the control unit 31 reads the target outlet temperature of the combustion burner 21.
  • the target outlet temperature stored in the memory or the like is read and acquired.
  • a characteristic curve indicating the relationship between the difference value (the difference between the target output and the current output) and the target outlet temperature of the combustion burner 21 is stored in a memory or the like.
  • the control unit 31 obtains the target outlet temperature of the combustion burner 21 by applying the difference value obtained in the process of step S122 to the characteristic curve of FIG.
  • step S125 the control unit 31 controls the amount of excess oxygen combustion gas supplied to the cathode 11a of the first-stage stack 11, that is, the flow amount of excess oxygen gas discharged after combustion by the combustion burner 21 (hereinafter referred to as “supply gas amount And the air blower 12 is controlled to achieve this supplied gas amount.
  • the supply gas amount is increased by a predetermined amount if ⁇ T> 0, and the supply gas amount is decreased by a predetermined amount if ⁇ T ⁇ 0.
  • the temperature difference .DELTA.T is controlled so as to approach zero by performing the control.
  • the outlet temperature is detected in step S121, if (outlet temperature)> (target temperature), the supplied gas amount is increased by a predetermined amount, and if (outlet temperature) ⁇ (target temperature), the supplied gas
  • the temperature of the first stage stack 11 is controlled to be the target temperature.
  • step S126 the control unit 31 calculates the required cathode air amount to be delivered from the air blower 12 based on the supply gas amount obtained in the process of step S125. That is, the amount of gas supplied from the air blower 12 to the second stage stack 11 via the combustion burner 21 and the first stage stack 11 is equal to the amount of gas supplied in the process of step S125. Then, the amount of air delivered by the air blower 12 is calculated.
  • step S127 based on the target outlet temperature of the combustion burner 21 acquired in the process of step S124, the control unit 31 calculates the required fuel amount of the combustion burner 21 required to achieve this temperature. Specifically, when the temperature of the second stage stack 32 does not reach the power generation possible temperature, the temperature of the combustion gas output from the combustion burner 21 is increased as the target output required for the system increases. Control.
  • step S128 the control unit 31 sets the amount of air obtained in the process of step S126 as the amount of air supplied to the cathode 11a, and further sets the amount of fuel supplied to the combustion burner 21 in step S129.
  • the air blower 12 and the second fuel pump 22 are controlled so that the amount of air and the amount of fuel become as follows.
  • step S130 the control unit 31 calculates the required cathode air amount to be sent from the air blower 12 based on the target output. In this process, with the combustion burner 21 stopped, the same process as the process shown in step S125 is performed.
  • the amount of supplied gas (corresponding to the amount of oxygen) is increased by a predetermined amount if ⁇ T> 0, and the supplied gas if ⁇ T ⁇ 0.
  • the temperature difference ⁇ T is controlled to approach zero.
  • the outlet temperature is detected in step S121, if (outlet temperature)> (target temperature), the amount of supplied gas (corresponding to the amount of oxygen) is increased by a predetermined amount, and (outlet temperature) ⁇ (target temperature) In the case of), the temperature of the first stage stack 11 is controlled to be the target temperature by reducing the amount of supplied gas by a predetermined amount.
  • step S131 the control unit 31 sets the amount of air to be delivered from the air blower 12 so as to be the amount of air obtained in the process of step S130.
  • the amount of gas supplied to the cathode 11a of the first-stage stack 11 and the amount of fuel supplied to the combustion burner 21 are controlled based on the excess oxygen ratio, whereby the second-stage stack from the cathode 11a of the first-stage stack 11 is performed. Since the gas flow rate at substantially the same temperature as the first stage stack operating temperature flowing into the cathode 32a of 32 increases, the second stage stack 32 can be rapidly heated to the target temperature (power generation possible temperature).
  • step S141 of FIG. 13 the control unit 31 calculates the target output required of the system, for example, from the amount of operation of the accelerator in the case of an on-vehicle system, and reads the result as the target output. .
  • step S142 the control unit 31 detects the current output of the fuel cell system 100a.
  • the current output can be determined based on the output current and voltage detected by the current / voltage sensor 42 provided in the first stage stack 11 and the current / voltage sensor 52 provided in the second stage stack 32. it can. Furthermore, the control unit 31 obtains the difference between the target output and the current output, and sets this as the difference value A.
  • step S143 the control unit 31 detects the temperature of the second stage stack 32. In this process, the stack temperature is detected as an average value, for example, by the inlet temperature sensor 51a and the outlet temperature sensor 51b provided in the second stage stack 32.
  • step S144 the control unit 31 determines whether it is necessary to raise the temperature of the second stage stack 32. For example, if the temperature of the second-stage stack 32 is equal to or higher than a predetermined value, electric power to be the target output can be generated even if the difference value A is equal to or higher than the predetermined value. 31 determines that it is not necessary to heat the second stage stack 32. If it is necessary to raise the temperature of the second stage stack 32 (needed in step S144), the process proceeds to step S145. On the other hand, when it is not necessary to raise the temperature of the second stage stack 32 (not needed in step S144), the process proceeds to step S155.
  • step S145 the control unit 31 determines whether the output of the second stack 32 has reached the target output. If the output of the second stage stack 32 has reached the target output (YES in step S145), the process proceeds to step S149. On the other hand, when the output of the second stage stack 32 does not reach the target output (NO in step S145), the process proceeds to step S147.
  • step S147 and S148 the control unit 31 reads the target cell voltage of the second stage stack 32 from the memory or the like, controls the cell voltage to a predetermined value, and increases as the operating temperature of the second stage stack 32 increases. Control so that the generated output reaches the target output.
  • This process carries out the same process as steps S33 and S34 in FIG. 4 described above. If this process ends, the process proceeds to step S151.
  • control unit 31 causes output of second-stage stack 32 to maintain the target output in step S149.
  • the current is controlled, and in step S150, the target output determination flag is turned on.
  • the second stage stack 32 can be heated by performing the cell voltage control, and the second stage When the output of the stack 32 has reached the target output, it is not necessary to further increase the output, so a flag indicating that the target output has been reached without performing cell voltage control is turned on.
  • step S151 the control unit 31 determines whether the temperature of the second stack 32 has reached the target temperature (the temperature at the time of normal operation of the second stack 32). If the temperature of the second stage stack 32 has not reached the target temperature (NO in step S151), the process proceeds to step S152. On the other hand, if the temperature of the second stack 32 has reached the target temperature (YES in step S151), the process proceeds to step S153.
  • step S152 the control unit 31 executes excess oxygen ratio control [3].
  • the details of the excess oxygen ratio control [3] will be described later with reference to the flowchart shown in FIG.
  • step S153 the control unit 31 turns on a target temperature attainment determination flag indicating that the temperature of the second stack 32 has reached the target temperature. Thereafter, the process proceeds to step S154.
  • step S154 the control unit 31 determines whether the second stage stack 32 has reached the target temperature and the target output. If the second stage stack 32 has reached the target temperature and the target output (YES in step S154), the process proceeds to step S155, and then the process ends. On the other hand, when the second stage stack 32 has not reached the target temperature and the target output (NO in step S154), the present process ends.
  • step S161 of FIG. 14 the control unit 31 calculates the amount of oxygen in the gas output from the first-stage stack 11. This calculation can be obtained from the relationship between the amount of oxygen supplied to the first stage stack 11 and the amount of oxygen used for power generation.
  • step S162 the control unit 31 reads the target minimum oxygen excess rate of the second stack 32.
  • the control unit 31 acquires the numerical value stored in a memory (not shown) by reading it.
  • step S163 the control unit 31 detects the output current of the second stage stack 32 by the current / voltage sensor 52.
  • step S164 the control unit 31 calculates the required minimum oxygen amount of the second stage stack 32. In this process, based on the output current detected in the process of step S163, the control unit 31 determines the amount of oxygen necessary to generate this current (minimum necessary amount of oxygen), and further, the step of this oxygen amount is performed.
  • the minimum oxygen content is determined by multiplying the target minimum oxygen excess rate acquired in the process of S162. At this time, since the excess oxygen rate read in the process of step S161 is set to a value lower than the excess oxygen rate during normal operation, the minimum oxygen amount is lower than the minimum oxygen amount during normal operation. .
  • step S165 the control unit 31 determines the minimum amount of oxygen obtained in the process of step S164 and the amount of oxygen in the gas output from the first stack 11 obtained in the process of step S161 (the amount of oxygen supplied in the second stage). Compare with. If the second stage supply oxygen amount is larger than the minimum oxygen amount (YES in step S165), the process proceeds to step S166. On the other hand, if the second stage supply oxygen amount is smaller than the minimum oxygen amount (NO in step S165), the process proceeds to step S167.
  • step S166 the control unit 31 sets the flow rate of the cooling air supplied to the second stage stack 32 from the cooling air flow control device 34 shown in FIG. 9 to zero. That is, if the minimum amount of oxygen required by the second stage stack 32 is smaller than the amount of oxygen contained in the gas delivered from the first stage stack 11 (the second stage supply oxygen amount), the second stage Since the oxygen required for the power generation of the stack 32 is sufficient, the cooling air from the air blower 12 is not supplied.
  • step S167 the control unit 31 calculates the flow rate of cooling air supplied from the cooling air flow control device 34 to the second stage stack 32. That is, if the minimum amount of oxygen required by the second stage stack 32 is larger than the amount of oxygen contained in the gas delivered from the first stage stack 11 (the second stage supply oxygen amount), the second stage Since the oxygen required for the power generation of the stack 32 is insufficient, the amount of cooling air to be supplied is obtained from the cooling air flow control device 34.
  • step S168 the control unit 31 adds the amount of air supplied to the first-stage stack 11 and the amount of air sent from the cooling air flow control device 34 to the first-stage stack 11 and the second-stage stack 32. Calculated as the total value of the air volume required by
  • step S169 the control unit 31 sets the amount of air supplied to the cathode 32a of the second stage stack 32.
  • the control unit 31 adjusts the opening degree of the cooling air flow control device 34 so that the amount of cooling air supplied to the cathode 32a becomes a desired numerical value.
  • the amount of oxygen supplied to the cathode 32a of the second-stage stack 32 is controlled so as not to be less than the minimum amount of oxygen obtained by multiplying the minimum necessary amount of oxygen by the oxygen excess rate.
  • the temperature of the second stage stack 32 can be immediately raised by reducing the cooling effect of the second stage stack 32.
  • the combustion burner is activated when the second stack 32 is started. At least one of the control of the amount of combustion gas delivered from 21, the control of the excess oxygen rate, and the control of setting the cell voltage within a predetermined range, the target output of the second stage stack 32 is quickly achieved.
  • the second stage stack 32 can quickly start generating power.
  • the fuel cell system 101a outputs more power from the combustion burner 21 (oxidant heater) as the target output required for the system is higher.
  • the temperature of the combustion gas is controlled to be high. Therefore, since the combustion gas output from the combustion burner 21 flows into the cathode 32a of the second stack 32 via the first stack 11, the second stack 32 can be rapidly heated, and the target temperature is reached. The time to reach can be further shortened.
  • the cooling air introduction passage 33 is connected to a flow path connecting the cathode 11 a outlet of the first stage stack 11 and the cathode 32 a inlet of the second stage stack 32, and an air blower is connected via the cooling air introduction passage 33. Since a part of the air delivered from 12 is introduced into the cathode 32a, the minimum amount of oxygen required in the cathode 32a of the second stage stack 32 can be assuredly ensured.
  • FIG. 18 is an explanatory view showing the fuel cell system 100 according to the present embodiment connected to the external load 61.
  • Electric power is supplied to the external load 61 via the relay device 63 by the fuel cell system 100 and the external power supply 62.
  • the fuel cell system 100 sets a target output and a target temperature in accordance with the required power of the external load 61.
  • the fuel cell system 100 has the configuration shown in FIG.
  • step S201 the control unit 31 (see FIG. 1) of the fuel cell system 100 detects the required power of the external load 61.
  • step S202 the control unit 31 obtains the generated power of the stack 11.
  • step S203 the control unit 31 calculates a difference value between the external load required power and the generated power of the stack 11.
  • step S204 the control unit 31 sets the target output and the target temperature of the stack 11 based on the difference value obtained in the process of step S203.
  • Power corresponding to the difference between the external load required power and the power generated by the stack 11 is supplied from the external power supply 62.
  • the control unit 31 sets a target output and a target temperature according to the difference value.
  • the fuel cell system 100 calculates the power supplied by the external power supply 62 as a difference between the external load required power and the generated power of the stack 11, and The target output of the stack 11 is changed. Therefore, the fuel cell system 100 can change the amount of power generation immediately and supply it to the external load 61 according to the power required by the external load 61. Therefore, the temperature increase rate of the stack 11 is controlled as necessary, and the amount of energy required for the temperature increase control can be reduced.
  • the control unit 31 may set the target output or the target temperature of the stack 11 in accordance with the difference value between the external load required power and the output power of the external power supply 62.
  • FIG. 20 is an explanatory view showing the fuel cell system 100 according to the present embodiment connected to the external load 61.
  • Electric power is supplied to the external load 61 by the fuel cell system 100 and the power storage device 64.
  • Fuel cell system 100 sets a target output and a target temperature according to the required power of external load 61 and the storage amount of power storage device 64.
  • the fuel cell system 100 has the configuration shown in FIG.
  • step S211 the control unit 31 (see FIG. 1) of the fuel cell system 100 detects the required power of the external load 61.
  • control unit 31 detects the ratio (SOC: State Of Charge) of the storage amount of power storage device 64.
  • the controller 31 sets a target output and a target temperature of the fuel cell system 100. This process can be set using the map shown in FIG. FIG. 22 is a map showing the relationship between the SOC and the external load required power. The control unit 31 sets a target output and a target temperature of the stack 11 based on this map.
  • the target output of the stack 11 fluctuates in accordance with the storage amount ratio (SOC) of the power storage device 64. Therefore, the fuel cell system 100 can change the amount of power generation immediately and supply it to the external load 61 according to the power required by the external load 61. Therefore, the temperature increase rate of the stack 11 is controlled in accordance with the ratio of the amount of stored power of the power storage device 64, and the amount of energy required for the temperature increase control can be reduced.
  • SOC storage amount ratio
  • FIG. 23 is an explanatory view showing how the fuel cell system 100 according to the present embodiment is connected to, for example, an external load 61 (in this embodiment, a vehicle motor). Electric power is supplied to the external load 61 by the fuel cell system 100 and the power storage device 64.
  • an external load 61 in this embodiment, a vehicle motor. Electric power is supplied to the external load 61 by the fuel cell system 100 and the power storage device 64.
  • the fuel cell system 100 is configured to be able to acquire data on the moving speed and moving direction of the vehicle from a control device mounted on the vehicle. Fuel cell system 100 estimates the required output after a predetermined time based on the moving direction and moving speed of the vehicle, and based on the estimated required output and the storage amount ratio (SOC) of power storage device 64, Set target output or target temperature.
  • SOC storage amount ratio
  • step S231 the control unit 31 (see FIG. 1) of the fuel cell system 100 acquires position information (including altitude information) of the vehicle on which the fuel cell system 100 is mounted.
  • This position information can be acquired, for example, from GPS information of a navigation system mounted on a vehicle.
  • control unit 31 calculates the moving direction of the vehicle.
  • control unit 31 detects the moving speed of the vehicle.
  • step S234 the control unit 31 estimates the required output after a predetermined time based on the moving speed and the moving direction of the vehicle.
  • control unit 31 detects the storage ratio (SOC) of power storage device 64.
  • step S236 the control unit 31 sets a target output or a target temperature based on the value of the SOC.
  • the target output or target temperature is set as time series data as shown in FIG.
  • this process can be set using the map shown in FIG. FIG. 26 is a map showing the relationship between the SOC and the estimated output.
  • the control unit 31 sets a target output and a target temperature of the stack 11 based on this map.
  • the temperature increase rate of the stack 11 is controlled according to the target output or the target temperature after a predetermined time estimated by the GPS information or the like. Therefore, the temperature rise control can be performed earlier than the time at which the predetermined output is required, and the energy consumption required for the temperature rise control can be reduced.
  • the oxygen excess rate of the oxidant output from the oxidant heating unit until the target output in normal operation or the target temperature is reached is reached.
  • at least one of the control to make the output voltage of the fuel cell within a predetermined range, and the heating control by the oxidant heating unit Therefore, the output of the fuel cell can be quickly reached to the target output.
  • the fuel cell system according to the present invention can rapidly raise the stack temperature to the target operation temperature.
  • the fuel cell system of the present invention has been described above based on the first to fifth embodiments, but the present invention is not limited to this, and the configuration of each part may be any configuration having the same function. It can be replaced.
  • a fuel cell system was mentioned as an example and explained to vehicles, this invention is not limited to vehicles.
  • the fuel cell system of the present invention can also be used as another application such as a fuel cell used for general household use.

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Abstract

A fuel cell system (100) is provided with a stack (11), an air blower (12), a fuel burner (21), and a controller (31). An air blower (12) is installed on the upstream side of a cathode (11a) of the stack (11) to supply air to the cathode (11a). The fuel burner (21) is installed between the air blower (12) and the cathode (11a) to heat the air output from the air blower (12). When the stack (11) starts, the controller (31) controls the supply to the cathode (11a) of air heated by the fuel burner (21) and the temperature increase in the stack (11). Furthermore, until the stack (11) reaches the specified target output or the target temperature after the stack (11) reached the temperature enabling power generation, the controller (31) controls at least one of (a) the control for setting the excess oxygen factor of air output from the combustion burner (21) lower than the excess oxygen factor at the target output of the stack, (b) the control for setting the output voltage of stack (11) in the specified range, and (c) the control of heating by the combustion burner (21).

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 of fuel cell system
　本発明は、燃料電池システム及び燃料電池システムの制御方法に係り、特に、燃料電池スタックを即時に起動してシステムに要求される目標出力に到達させる技術に関する。 The present invention relates to a fuel cell system and a control method of a fuel cell system, and more particularly to a technology for instantly starting a fuel cell stack to reach a target output required for the system.
　固体酸化物型燃料電池システム等の燃料電池システムでは、燃料電池スタック（以下、単に「スタック」と略す）を起動させる際に、スタックの温度を発電開始温度まで昇温させる必要がある。そのため、従来の燃料電池システムでは、スタックのカソード上流側に燃焼バーナを設置し、スタック起動時に燃焼バーナを燃焼させ、発生する燃焼ガスをカソードに供給してスタックを昇温している。そして、スタックが発電可能温度に達した後にスタックによる発電を開始し、スタック温度が所定値に達し、且つ、発電電流または発電電力が所定値に達した場合に、燃焼バーナを停止させて定格運転状態とする（例えば、特許文献１参照）。 In a fuel cell system such as a solid oxide fuel cell system, when activating a fuel cell stack (hereinafter simply referred to as "stack"), it is necessary to raise the temperature of the stack to a power generation start temperature. Therefore, in the conventional fuel cell system, a combustion burner is installed on the cathode upstream side of the stack, the combustion burner is burned when the stack is started, and the generated combustion gas is supplied to the cathode to raise the temperature of the stack. Then, after the stack reaches the power generation temperature, the stack starts power generation, and when the stack temperature reaches a predetermined value and the generated current or the generated power reaches a predetermined value, the combustion burner is stopped and the rated operation is performed. It is set as a state (for example, refer patent document 1).
特開２００９－１４６６４７号公報JP, 2009-146647, A
　しかしながら、特許文献１に開示された従来の燃料電池システムでは、燃焼バーナを停止させるタイミングを制御することを目的としている。具体的には、スタックが定格運転状態(一定の出力を得ることができる状態)に至る以前に、燃焼バーナによる加熱を停止し、その後、徐々に定格運転に移行させている。それゆえ、燃焼バーナを停止することによってスタックの昇温速度を遅延させてしまう場合があり、急速に目標出力へ到達させることが要求される車載用燃料電池への適用は難しいという問題があった。 However, the conventional fuel cell system disclosed in Patent Document 1 aims to control the timing at which the combustion burner is stopped. Specifically, heating by the combustion burner is stopped before the stack reaches a rated operation state (a state in which a constant output can be obtained), and thereafter, the operation is gradually shifted to the rated operation. Therefore, stopping the combustion burner may delay the temperature rising rate of the stack, and there has been a problem that it is difficult to apply it to an on-vehicle fuel cell that is required to rapidly reach the target output. .
　本発明は、上記の課題を解決するためになされたものであり、燃料電池の起動時に即時に目標出力に到達させることが可能な燃料電池システム及び燃料電池システムの制御方法を提供することを目的とする。 The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a fuel cell system and a control method of the fuel cell system capable of achieving the target output immediately upon start of the fuel cell. I assume.
　上記目的を達成するため、本発明の一態様に係る燃料電池システムは、アノードに改質ガスが供給され、カソードに酸化剤が供給されて発電する燃料電池と、前記カソードの上流側に設けられ、前記カソードに酸化剤を供給する酸化剤供給部と、前記酸化剤供給部と前記カソードとの間に設けられ、前記酸化剤供給部より出力される酸化剤を加熱する酸化剤加熱部と、前記燃料電池の起動時に、前記酸化剤加熱部で加熱された酸化剤を前記カソードに供給して前記燃料電池を昇温する制御を行い、かつ、前記燃料電池が発電可能温度に到達した後に、前記燃料電池が所定の目標出力或いは目標温度に到達するまで、（ａ）前記酸化剤加熱部より出力される酸化剤の酸素過剰率を、前記燃料電池の目標出力での酸素過剰率よりも低く設定する制御、（ｂ）前記燃料電池の出力電圧を所定の範囲内とする制御、（ｃ）前記酸化剤加熱部による加熱制御、のうちの少なくとも一つの制御を行う制御部と、を備える。 In order to achieve the above object, in a fuel cell system according to an aspect of the present invention, a fuel cell is provided with a reformed gas supplied to an anode and an oxidant supplied to a cathode to generate electricity, and provided on the upstream side of the cathode An oxidizing agent supply unit for supplying an oxidizing agent to the cathode, and an oxidizing agent heating unit provided between the oxidizing agent supply unit and the cathode and heating the oxidizing agent output from the oxidizing agent supply unit; At startup of the fuel cell, the oxidant heated by the oxidant heating unit is supplied to the cathode to perform control to raise the temperature of the fuel cell, and after the fuel cell reaches the power generation possible temperature, (A) The oxygen excess rate of the oxidant output from the oxidant heating unit is lower than the oxygen excess rate at the target output of the fuel cell until the fuel cell reaches a predetermined target output or target temperature Set Please, and a control unit for performing at least one control of the heating control, among by (b) control in the range of output voltage of a predetermined said fuel cell, (c) the oxidizing agent heating unit.
　また、本発明の一態様に係る燃料電池システムの制御方法は、燃料電池のカソードの上流側に設けられ、前記カソードに酸化剤を供給する酸化剤供給部と、前記酸化剤供給部と前記カソードとの間に設けられ、前記酸化剤供給部より出力される酸化剤を加熱する酸化剤加熱部と、を備える燃料電池システムにおいて、前記燃料電池の起動時に、前記酸化剤加熱部で加熱された酸化剤を前記カソードに供給して前記燃料電池を昇温する制御を行うステップと、前記燃料電池が発電可能温度に到達した後に、前記燃料電池が所定の目標出力或いは目標温度に到達するまで、（ａ）前記酸化剤加熱部より出力される酸化剤の酸素過剰率を、前記燃料電池の目標出力での酸素過剰率よりも低く設定する制御、（ｂ）前記燃料電池の出力電圧を所定の範囲内とする制御、（ｃ）前記酸化剤加熱部による加熱制御、のうちの少なくとも一つの制御を行うステップ、を備える。 Further, in the control method of a fuel cell system according to one aspect of the present invention, an oxidant supply unit provided on the upstream side of a cathode of a fuel cell and supplying an oxidant to the cathode, the oxidant supply unit, and the cathode And a fuel cell system including an oxidant heating unit for heating an oxidant output from the oxidant supply unit, the fuel cell system being heated by the oxidant heating unit when the fuel cell is started. Supplying an oxidant to the cathode to control the temperature rise of the fuel cell; and until the fuel cell reaches a predetermined target output or target temperature after the fuel cell reaches the power generation possible temperature, (A) control to set the oxygen excess rate of the oxidant output from the oxidant heating unit lower than the oxygen excess rate at the target output of the fuel cell, (b) setting the output voltage of the fuel cell to a predetermined value Control to 囲内 comprises the step of performing at least one control of the heating control, among by the oxidizing agent heating unit (c).
図１は、本発明の第１実施形態に係る燃料電池システムの構成を示すブロック図である。FIG. 1 is a block diagram showing the configuration of a fuel cell system according to a first embodiment of the present invention. 図２は、本発明の第１実施形態に係る燃料電池システムの、スタック起動時における処理手順を示すフローチャートである。FIG. 2 is a flowchart showing a processing procedure at the time of stack activation of the fuel cell system according to the first embodiment of the present invention. 図３は、本発明の第１実施形態に係る燃料電池システムの、スタック加熱制御の処理手順を示すフローチャートである。FIG. 3 is a flowchart showing a processing procedure of stack heating control of the fuel cell system according to the first embodiment of the present invention. 図４は、本発明の第１実施形態に係る燃料電池システムの、スタック昇温制御の処理手順を示すフローチャートである。FIG. 4 is a flowchart showing a processing procedure of stack temperature increase control of the fuel cell system according to the first embodiment of the present invention. 図５は、本発明の第１実施形態に係る燃料電池システムの、バーナ及び酸素過剰率制御［１］の処理手順を示すフローチャートである。FIG. 5 is a flowchart showing a processing procedure of burner and excess oxygen ratio control [1] of the fuel cell system according to the first embodiment of the present invention. 図６は、本発明の第１実施形態に係る燃料電池システムの、バーナ及び酸素過剰率制御［２］の処理手順を示すフローチャートである。FIG. 6 is a flow chart showing a processing procedure of burner and excess oxygen ratio control [2] of the fuel cell system according to the first embodiment of the present invention. 図７は、本発明の第１実施形態に係る燃料電池システムの、酸素過剰率制御［１］の処理手順を示すフローチャートである。FIG. 7 is a flowchart showing a processing procedure of excess oxygen ratio control [1] of the fuel cell system according to the first embodiment of the present invention. 図８は、本発明の第１実施形態に係る燃料電池システムの、酸素過剰率制御［２］の処理手順を示すフローチャートである。FIG. 8 is a flowchart showing a processing procedure of excess oxygen ratio control [2] of the fuel cell system according to the first embodiment of the present invention. 図９は、本発明の第２実施形態に係る燃料電池システムの構成を示すブロック図である。FIG. 9 is a block diagram showing the configuration of a fuel cell system according to a second embodiment of the present invention. 図１０は、本発明の第２実施形態に係る燃料電池システムの、スタック起動時における処理手順を示すフローチャートである。FIG. 10 is a flowchart showing a processing procedure at the time of stack activation of the fuel cell system according to the second embodiment of the present invention. 図１１は、本発明の第２実施形態に係る燃料電池システムの、２段目スタック昇温制御［１］の処理手順を示すフローチャートである。FIG. 11 is a flowchart showing the processing procedure of the second stage stack temperature increase control [1] of the fuel cell system according to the second embodiment of the present invention. 図１２は、本発明の第２実施形態に係る燃料電池システムの、バーナ及び酸素過剰率制御［３］の処理手順を示すフローチャートである。FIG. 12 is a flow chart showing a processing procedure of burner and oxygen excess ratio control [3] of the fuel cell system according to the second embodiment of the present invention. 図１３は、本発明の第２実施形態に係る燃料電池システムの、２段目スタック昇温制御［２］の処理手順を示すフローチャートである。FIG. 13 is a flowchart showing the processing procedure of the second stage stack temperature increase control [2] of the fuel cell system according to the second embodiment of the present invention. 図１４は、本発明の第２実施形態に係る燃料電池システムの、酸素過剰率制御［３］の処理手順を示すフローチャートである。FIG. 14 is a flowchart showing a processing procedure of excess oxygen ratio control [3] of the fuel cell system according to the second embodiment of the present invention. 図１５は、本発明の実施形態に係る燃料電池システムの、目標出力と起動時に投入するエネルギーとの関係を示す特性図である。FIG. 15 is a characteristic diagram showing the relationship between the target output and the energy input at startup of the fuel cell system according to the embodiment of the present invention. 図１６は、本発明の実施形態に係る燃料電池システムの、電流密度と、セル電圧と、出力密度との関係を示す特性図である。FIG. 16 is a characteristic diagram showing the relationship between the current density, the cell voltage and the power density of the fuel cell system according to the embodiment of the present invention. 図１７は、本発明の実施形態に係る燃料電池システムの、目標出力と現状出力との差分値と、燃焼バーナの出力温度との関係を示す特性図である。FIG. 17 is a characteristic diagram showing the relationship between the difference value between the target output and the current output of the fuel cell system according to the embodiment of the present invention and the output temperature of the combustion burner. 図１８は、本発明の第３実施形態に係る燃料電池システムを、外部負荷に接続した構成を示すブロック図である。FIG. 18 is a block diagram showing a configuration in which the fuel cell system according to the third embodiment of the present invention is connected to an external load. 図１９は、本発明の第３実施形態に係る燃料電池システムの処理動作を示すフローチャートである。FIG. 19 is a flowchart showing the processing operation of the fuel cell system according to the third embodiment of the present invention. 図２０は、本発明の第４実施形態に係る燃料電池システムを、外部負荷に接続した構成を示すブロック図である。FIG. 20 is a block diagram showing a configuration in which the fuel cell system according to the fourth embodiment of the present invention is connected to an external load. 図２１は、本発明の第４実施形態に係る燃料電池システムの処理動作を示すフローチャートである。FIG. 21 is a flowchart showing the processing operation of the fuel cell system according to the fourth embodiment of the present invention. 図２２は、本発明の第４実施形態に係る燃料電池システムで用いるＳＯＣと外部負荷の要求出力との関係を示すマップである。FIG. 22 is a map showing the relationship between the SOC used in the fuel cell system according to the fourth embodiment of the present invention and the required output of the external load. 図２３は、本発明の第５実施形態に係る燃料電池システムを、外部負荷に接続した構成を示すブロック図である。FIG. 23 is a block diagram showing a configuration in which the fuel cell system according to the fifth embodiment of the present invention is connected to an external load. 図２４は、本発明の第５実施形態に係る燃料電池システムの処理動作を示すフローチャートである。FIG. 24 is a flowchart showing the processing operation of the fuel cell system according to the fifth embodiment of the present invention. 図２５は、本発明の第５実施形態に係る燃料電池システムで用いる目標温度及び目標出力の時系列的なデータを示す特性図である。FIG. 25 is a characteristic diagram showing time-series data of a target temperature and a target output used in a fuel cell system according to a fifth embodiment of the present invention. 図２６は、本発明の第５実施形態に係る燃料電池システムで用いるＳＯＣと出力との関係を示すマップである。FIG. 26 is a map showing the relationship between the SOC and the output used in the fuel cell system according to the fifth embodiment of the present invention.
　以下、本発明の第１乃至５実施形態を図面に基づいて説明する。 Hereinafter, first to fifth embodiments of the present invention will be described based on the drawings.
（第１実施形態）
　図１は、本実施形態に係る燃料電池システム１００の構成を示すブロック図である。図１に示すように、燃料電池システム１００は、燃料電池スタック１１（以下、スタック１１と略す）、空気ブロワ（酸化剤供給部）１２、熱交換器１３、第１燃料ポンプ１４、熱交換型プレ改質装置１５、及び蒸発器２５を備えている。 First Embodiment
FIG. 1 is a block diagram showing the configuration of a fuel cell system 100 according to the present embodiment. As shown in FIG. 1, the fuel cell system 100 includes a fuel cell stack 11 (hereinafter, abbreviated as stack 11), an air blower (oxidizer supply unit) 12, a heat exchanger 13, a first fuel pump 14, and a heat exchange type. A pre-reformer 15 and an evaporator 25 are provided.
　スタック１１は、カソード１１ａ及びアノード１１ｂを備える。空気ブロワ１２は、カソード１１ａに空気（酸化剤）を供給する。熱交換器１３は、空気ブロワ１２より送出される空気を加熱する。第１燃料ポンプ１４は、スタック１１のアノード１１ｂに炭化水素燃料等の燃料を供給する。蒸発器２５は、第１燃料ポンプ１４より送出される燃料を気化させる。熱交換型プレ改質装置１５は、蒸発器２５で気化した燃料を改質してアノード１１ｂに供給する。 The stack 11 includes a cathode 11a and an anode 11b. The air blower 12 supplies air (oxidant) to the cathode 11a. The heat exchanger 13 heats the air delivered from the air blower 12. The first fuel pump 14 supplies fuel such as hydrocarbon fuel to the anode 11 b of the stack 11. The evaporator 25 vaporizes the fuel delivered from the first fuel pump 14. The heat exchange type pre-reforming apparatus 15 reforms the fuel vaporized by the evaporator 25 and supplies the reformed fuel to the anode 11 b.
　熱交換型プレ改質装置１５は、プレ改質器１６、及びプレ改質器１６を加熱する燃焼器１７を備えている。燃焼器１７には、空気ブロワ１２より送出される空気の一部、及びアノードオフガス（アノード１１ｂより排出されるガス）が供給されて燃焼し、プレ改質器１６を加熱する。燃焼器１７の出力側は熱交換器１３の高温側に接続されている。燃焼器１７より出力される排ガスは熱交換器１３の加熱用ガスとして用いられる。 The heat exchange type pre-reformer 15 includes a pre-reformer 16 and a combustor 17 that heats the pre-reformer 16. A part of air sent from the air blower 12 and an anode off gas (a gas discharged from the anode 11 b) are supplied to the combustor 17 and burned to heat the pre-reformer 16. The output side of the combustor 17 is connected to the high temperature side of the heat exchanger 13. The exhaust gas output from the combustor 17 is used as a heating gas for the heat exchanger 13.
　プレ改質器１６には、空気ブロワ１２より送出される空気の一部、第１燃料ポンプ１４より送出され蒸発器２５で気化された燃料、及びアノードオフガスの一部が、供給され、燃焼器１７で発生する熱により該燃料を改質し、改質した燃料をスタック１１のアノード１１ｂに供給する。 A portion of the air delivered from the air blower 12, the fuel delivered from the first fuel pump 14 and the fuel vaporized in the evaporator 25, and a portion of the anode off gas are supplied to the pre-reformer 16 and the combustor The heat generated at 17 reforms the fuel, and the reformed fuel is supplied to the anode 11 b of the stack 11.
　空気ブロワ１２の出力側は、熱交換器１３の低温側に接続されている。熱交換器１３の高温側の出口は、スタック１１の起動時にカソード１１ａを加熱するための燃焼バーナ（酸化剤加熱部）２１に接続されている。燃焼バーナ２１は、第２燃料ポンプ２２に接続され、第２燃料ポンプ２２より燃料が供給される。従って、燃焼バーナ２１には、熱交換器１３で加熱された空気、及び第２燃料ポンプ２２より送出される燃料が、供給されて燃焼する。そして、この燃焼ガスがスタック１１のカソード１１ａに供給される。 The output side of the air blower 12 is connected to the low temperature side of the heat exchanger 13. The outlet on the high temperature side of the heat exchanger 13 is connected to a combustion burner (oxidant heater) 21 for heating the cathode 11 a when the stack 11 is started. The combustion burners 21 are connected to the second fuel pump 22, and fuel is supplied from the second fuel pump 22. Therefore, the air heated by the heat exchanger 13 and the fuel delivered from the second fuel pump 22 are supplied to the combustion burner 21 and burnt. Then, the combustion gas is supplied to the cathode 11 a of the stack 11.
　アノード１１ｂの出力側には、アノードオフガス循環器２３が設けられている。アノードオフガス循環器２３は、アノード１１ｂより出力されるアノードオフガスを２系統に分岐させる。具体的には、アノードオフガス循環器２３は、一方に分岐したアノードオフガスをプレ改質器１６に供給し、他方に分岐したアノードオフガスを燃焼器１７に供給する。 An anode off gas circulator 23 is provided on the output side of the anode 11 b. The anode off gas circulator 23 branches the anode off gas output from the anode 11 b into two systems. Specifically, the anode off gas circulator 23 supplies the anode off gas branched to one to the pre-reformer 16 and supplies the anode off gas branched to the other to the combustor 17.
　空気ブロワ１２と熱交換型プレ改質装置１５との間には、流量制御装置１９，２０が設けられている。流量制御装置１９，２０は、プレ改質器１６に供給する空気流量及び燃焼器１７に供給する空気流量が所望の流量となるように、これらの空気流量を調整する。 Flow control devices 19 and 20 are provided between the air blower 12 and the heat exchange type pre-reforming apparatus 15. The flow control devices 19 and 20 adjust the flow rates of the air supplied to the pre-reformer 16 and the air flow supplied to the combustor 17 so as to be desired flow rates.
　スタック１１には、入口付近の温度を測定する入口温度センサ４１ａと、出口付近の温度を測定する出口温度センサ４１ｂと、スタック１１の出力電流及び電圧を検出する電流・電圧センサ４２とが設けられている。 The stack 11 is provided with an inlet temperature sensor 41a that measures the temperature near the inlet, an outlet temperature sensor 41b that measures the temperature near the outlet, and a current / voltage sensor 42 that detects the output current and voltage of the stack 11. ing.
　また、燃料電池システム１００は、システム全体を総括的に制御する制御部（制御部）３１を備えている。特に、制御部３１は、スタック１１に設けられる入口温度センサ４１ａ及び出口温度センサ４１ｂで測定されるスタック温度（例えば、入口温度と出口温度の平均値）と、電流・電圧センサ４２で測定され演算される発電出力とに基づいて、第２燃料ポンプ２２による燃料の供給量及び空気ブロワ１２による空気量を制御する処理を行う。なお、制御部３１は、例えば、中央演算ユニット（ＣＰＵ）や、ＲＡＭ、ＲＯＭ、ハードディスク等の記憶部からなる一体型のコンピュータとして構成することができる。 In addition, the fuel cell system 100 includes a control unit (control unit) 31 that collectively controls the entire system. In particular, the control unit 31 measures and calculates the stack temperature (for example, the average value of the inlet temperature and the outlet temperature) measured by the inlet temperature sensor 41a and the outlet temperature sensor 41b provided in the stack 11, and the current / voltage sensor 42 Based on the generated power output, a process of controlling the amount of fuel supplied by the second fuel pump 22 and the amount of air by the air blower 12 is performed. The control unit 31 can be configured as, for example, an integrated computer including storage units such as a central processing unit (CPU), a RAM, a ROM, and a hard disk.
　次に、燃料電池システム１００の、起動時における処理動作を、図２～図８に示すフローチャートを参照して説明する。図２は、燃料電池システム１００の起動時におけるスタックの昇温操作の全体の処理手順を示すフローチャートである。 Next, the processing operation of the fuel cell system 100 at the time of start-up will be described with reference to the flowcharts shown in FIGS. FIG. 2 is a flowchart showing the entire processing procedure of the temperature raising operation of the stack at the time of startup of the fuel cell system 100.
　初めに、ステップＳ１１において、制御部３１は、スタック１１を起動するか否かを判断する。スタック１１を起動する場合には（ステップＳ１１でＹＥＳ）、ステップＳ１２において、制御部３１は、燃焼バーナ２１によるスタック１１の加熱が終了したか否かを判断する。スタック１１の加熱が終了していなければ（ステップＳ１２でＮＯ）、ステップＳ１３において、制御部３１は、燃焼バーナ２１によるスタック１１の加熱制御を継続して行う。スタック加熱制御の詳細については、図３に示すフローチャートを参照して後述する。その後、ステップＳ１４に処理を進める。 First, in step S11, the control unit 31 determines whether to activate the stack 11. When starting the stack 11 (YES in step S11), in step S12, the control unit 31 determines whether the heating of the stack 11 by the combustion burner 21 has ended. If the heating of the stack 11 is not completed (NO in step S12), the control unit 31 continues the heating control of the stack 11 by the combustion burner 21 in step S13. Details of the stack heating control will be described later with reference to the flowchart shown in FIG. Thereafter, the process proceeds to step S14.
　ステップＳ１４において、制御部３１は、スタック昇温制御が終了しているか否かを判断する。スタック昇温制御が終了していなければ（ステップＳ１４でＮＯ）、ステップＳ１５において、制御部３１は、スタック昇温制御を行う。スタック昇温制御の詳細については、図４に示すフローチャートを参照して後述する。その後、本処理をリターンする。なお、「スタック加熱制御」とはスタック１１を発電可能温度まで昇温させる制御であり、「スタック昇温制御」とは発電可能温度まで昇温されたスタック１１の温度を更に昇温して発電目標温度まで上昇させる制御である。 In step S14, the control unit 31 determines whether the stack temperature increase control has ended. If the stack temperature increase control has not ended (NO in step S14), the control unit 31 performs stack temperature increase control in step S15. Details of the stack temperature increase control will be described later with reference to the flowchart shown in FIG. Thereafter, the process returns. Note that "stack heating control" is control for raising the temperature of the stack 11 to a temperature at which power can be generated, and "stack heating control" means that the temperature of the stack 11 raised to the temperature at which power can be generated is further raised to generate power. It is control to raise to target temperature.
　次に、図２のステップＳ１３に示した燃焼バーナ２１によるスタック１１の加熱制御の処理手順を、図３に示すフローチャートを参照して説明する。 Next, the processing procedure of the heating control of the stack 11 by the combustion burner 21 shown in step S13 of FIG. 2 will be described with reference to the flowchart shown in FIG.
　初めに、ステップＳ２１において、制御部３１は、空気ブロワ１２を起動して、燃焼バーナ２１に空気を供給する。 First, in step S21, the control unit 31 activates the air blower 12 to supply air to the combustion burners 21.
　ステップＳ２２において、制御部３１は、燃焼バーナ２１を起動して、第２燃料ポンプ２２より供給される燃料及び空気ブロワ１２より供給される空気を燃焼させる。そして、燃焼バーナ２１にて生成される燃焼ガスをスタック１１のカソード１１ａ内に供給し、カソード１１ａを昇温する。 In step S <b> 22, the control unit 31 activates the combustion burner 21 to burn the fuel supplied from the second fuel pump 22 and the air supplied from the air blower 12. Then, the combustion gas generated by the combustion burner 21 is supplied into the cathode 11 a of the stack 11 to raise the temperature of the cathode 11 a.
　ステップＳ２３において、制御部３１は、空気ブロワ１２からカソード１１ａ内に供給される空気量を制御する。ステップＳ２４において、制御部３１は、燃焼バーナ２１に供給する燃料量を制御する。これにより、制御部３１は、燃焼バーナ２１からカソード１１ａに供給される燃焼ガス量、及び燃焼バーナ２１の出口温度が所定の状態になるように制御する。 In step S23, the control unit 31 controls the amount of air supplied from the air blower 12 into the cathode 11a. In step S24, the control unit 31 controls the amount of fuel supplied to the combustion burners 21. Thus, the control unit 31 controls the amount of combustion gas supplied from the combustion burner 21 to the cathode 11 a and the outlet temperature of the combustion burner 21 to be in predetermined states.
　ステップＳ２５において、制御部３１は、入口温度センサ４１ａ及び出口温度センサ４１ｂによりスタック１１の温度（例えば、入口温度と出口温度の平均値）を検出する。ステップＳ２６において、制御部３１は、スタック１１の温度が所定の温度（スタック１１の発電可能温度）に達したか否かを判断する。スタック１１の温度が所定温度に達していなければ（ステップＳ２６でＮＯ）、ステップＳ２３に処理を戻す。スタック１１の温度が所定温度に達していれば（ステップＳ２６でＹＥＳ）、ステップＳ２７において、制御部３１は、燃焼バーナ２１による加熱を終了して、加熱終了判定のフラグをオンとする。こうして、制御部３１は、スタック１１を発電可能温度まで昇温させることができる。 In step S25, the control unit 31 detects the temperature of the stack 11 (for example, the average value of the inlet temperature and the outlet temperature) by the inlet temperature sensor 41a and the outlet temperature sensor 41b. In step S26, the control unit 31 determines whether the temperature of the stack 11 has reached a predetermined temperature (the temperature at which the stack 11 can generate power). If the temperature of the stack 11 has not reached the predetermined temperature (NO in step S26), the process returns to step S23. If the temperature of the stack 11 has reached the predetermined temperature (YES in step S26), the control unit 31 ends the heating by the combustion burner 21 in step S27, and turns on the flag of the heating end determination. Thus, the control unit 31 can raise the temperature of the stack 11 to the power generation possible temperature.
　次に、図２のステップＳ１５に示したスタック昇温制御の詳細な処理を、図４に示すフローチャートを参照して説明する。図４に示すステップＳ３１において、制御部３１は、スタック１１の温度及び（電力及び電流より演算される）スタック１１の出力を検出する。ステップＳ３２において、制御部３１は、スタック１１の出力が目標出力に到達しているか否かを判断する。 Next, the detailed processing of the stack temperature increase control shown in step S15 of FIG. 2 will be described with reference to the flowchart shown in FIG. In step S31 shown in FIG. 4, the control unit 31 detects the temperature of the stack 11 and the output of the stack 11 (calculated from the power and current). In step S32, the control unit 31 determines whether the output of the stack 11 has reached the target output.
　スタック１１の出力が目標出力に到達している場合には（ステップＳ３２でＹＥＳ）、ステップＳ３５において、制御部３１は、スタック１１の発電出力が目標出力になるように電流値を制御する。ステップＳ３６において、制御部３１は、スタック１１の出力が目標出力に到達したことを示すフラグをオンとする。その後、ステップＳ３７に処理を進める。 If the output of the stack 11 has reached the target output (YES in step S32), in step S35, the control unit 31 controls the current value such that the generated output of the stack 11 becomes the target output. In step S36, the control unit 31 turns on a flag indicating that the output of the stack 11 has reached the target output. Thereafter, the process proceeds to step S37.
　一方、スタック１１の出力が目標出力に達していない場合には（ステップＳ３２でＮＯ）、ステップＳ３３において、制御部３１は、メモリ（図示省略）等に記憶されているセル電圧目標値を読み込む。ステップＳ３４において、制御部３１は、セル電圧目標値となるようにセル電圧を制御する。具体的には、制御部３１は、セル電圧が所定値となるように制御することによって、スタック１１の温度の上昇に伴い、スタック１１の出力が目標出力となるように制御する。なお、スタック１１は、複数のセルが積層された構造体である。セル電圧とは各セルの出力電圧のことである。セル電圧は、０．５Ｖ程度に制御することが望ましい。セル電圧の制御については、図１６を参照して後述する。その後、ステップＳ３７に処理を進める。 On the other hand, when the output of the stack 11 has not reached the target output (NO in step S32), in step S33, the control unit 31 reads the cell voltage target value stored in a memory (not shown) or the like. In step S34, the control unit 31 controls the cell voltage such that the cell voltage target value is obtained. Specifically, the control unit 31 controls the cell voltage to be a predetermined value, and controls the output of the stack 11 to be a target output as the temperature of the stack 11 rises. The stack 11 is a structure in which a plurality of cells are stacked. The cell voltage is the output voltage of each cell. It is desirable to control the cell voltage to about 0.5V. Control of the cell voltage will be described later with reference to FIG. Thereafter, the process proceeds to step S37.
　ステップＳ３７において、制御部３１は、スタック１１の目標出力が、予め設定した所定出力よりも大きいか否かを判断する。具体的には、制御部３１は、スタック１１の目標出力が予め設定した所定値Ｘ１よりも大きいか否かを判断する。図１５の特性曲線に示すように、スタック１１の目標出力とスタック１１に投入するエネルギーとの関係は、燃焼バーナ２１のオン時とオフ時で相違する。 In step S37, the control unit 31 determines whether the target output of the stack 11 is larger than a predetermined output set in advance. Specifically, the control unit 31 determines whether the target output of the stack 11 is larger than a predetermined value X1 set in advance. As shown in the characteristic curve of FIG. 15, the relationship between the target output of the stack 11 and the energy input to the stack 11 differs between the on time and the off time of the combustion burner 21.
　図１５の曲線Ｑ１は燃焼バーナ２１のオン時の特性を示し、曲線Ｑ２は燃焼バーナ２１のオフ時の特性を示している。図１５から、スタック１１の目標出力が所定値Ｘ１を超えると燃焼バーナ２１をオンとした方が、投入エネルギーを低減できることが判る。従って、燃料電池システム１００では、スタック１１の目標出力が所定値Ｘ１を上回る場合には、燃焼バーナ２１を作動させることによりスタック１１を目標温度まで昇温させる。一方、スタック１１の目標出力が所定値Ｘ１を下回る場合には、燃焼バーナ２１を作動させずにスタック１１を昇温させる。ここで、「目標温度」とは、スタック１１が定常運転されているときの温度であり、発電可能温度よりも高い温度である。 Curve Q1 in FIG. 15 shows the on-time characteristics of the combustion burner 21, and curve Q2 shows the off-time characteristics of the combustion burner 21. It can be seen from FIG. 15 that the input energy can be reduced by turning on the combustion burner 21 when the target output of the stack 11 exceeds the predetermined value X1. Therefore, in the fuel cell system 100, when the target output of the stack 11 exceeds the predetermined value X1, the stack burner 11 is heated to the target temperature by operating the combustion burners 21. On the other hand, when the target output of the stack 11 falls below the predetermined value X1, the temperature of the stack 11 is raised without operating the combustion burners 21. Here, the “target temperature” is a temperature when the stack 11 is in steady operation, and is a temperature higher than the power generation possible temperature.
　スタック１１の目標出力が所定値Ｘ１よりも大きい場合には（ステップＳ３７でＹＥＳ）、ステップＳ３８において、制御部３１は、スタック１１の温度が目標温度に到達したか否かを判断する。スタック１１の温度が目標温度に到達していない場合には（ステップＳ３８でＮＯ）、ステップＳ３９において、制御部３１は、バーナ及び酸素過剰率制御［１］を実行する。バーナ及び酸素過剰率制御［１］の詳細については、図５に示すフローチャートを参照して後述する。一方、スタック１１の温度が目標温度に到達している場合には（ステップＳ３８でＹＥＳ）、ステップＳ４０において、制御部３１は、バーナ及び酸素過剰率制御［２］を実行する。バーナ及び酸素過剰率制御［２］の詳細については、図６に示すフローチャートを参照して後述する。 If the target output of the stack 11 is larger than the predetermined value X1 (YES in step S37), in step S38, the control unit 31 determines whether the temperature of the stack 11 has reached the target temperature. If the temperature of the stack 11 has not reached the target temperature (NO in step S38), the controller 31 executes burner and oxygen excess ratio control [1] in step S39. The details of the burner and the excess oxygen ratio control [1] will be described later with reference to the flowchart shown in FIG. On the other hand, when the temperature of the stack 11 has reached the target temperature (YES in step S38), the control unit 31 executes burner and oxygen excess ratio control [2] in step S40. The details of the burner and the excess oxygen ratio control [2] will be described later with reference to the flowchart shown in FIG.
　また、ステップＳ３７において、スタック１１の目標出力が所定値Ｘ１以下であると判断された場合には（ステップＳ３７でＮＯ）、ステップＳ４１において、制御部３１は、スタック１１の温度が目標温度に到達したか否かを判断する。スタック１１の温度が目標温度に到達していない場合には（ステップＳ４１でＮＯ）、ステップＳ４２において、制御部３１は、酸素過剰率制御［１］を実行する。酸素過剰率制御［１］の詳細については、図７に示すフローチャートを参照して後述する。一方、スタック１１の温度が目標温度に到達している場合には（ステップＳ４１でＹＥＳ）、ステップＳ４３において、制御部３１は、酸素過剰率制御［２］を実行する。酸素過剰率制御［２］の詳細については、図８に示すフローチャートを参照して後述する。 When it is determined in step S37 that the target output of the stack 11 is less than or equal to the predetermined value X1 (NO in step S37), the controller 31 determines that the temperature of the stack 11 reaches the target temperature in step S41. Determine if you If the temperature of the stack 11 has not reached the target temperature (NO in step S41), the control unit 31 executes excess oxygen ratio control [1] in step S42. The details of the excess oxygen ratio control [1] will be described later with reference to the flowchart shown in FIG. On the other hand, when the temperature of the stack 11 has reached the target temperature (YES in step S41), in step S43, the control unit 31 executes excess oxygen ratio control [2]. The details of the excess oxygen ratio control [2] will be described later with reference to the flowchart shown in FIG.
　バーナ及び酸素過剰率制御［１］、［２］及び酸素過剰率制御［１］、［２］のうちのいずれかの処理が実行されると、ステップＳ４４において、制御部３１は、スタック１１の温度が目標温度に到達したか否かを判断する。スタック１１の温度が目標温度に到達した場合には（ステップＳ４４でＹＥＳ）、ステップＳ４５において、制御部３１は、スタック１１の温度が目標温度に到達したことを示す目標温度到達判定フラグをオンとする。 When any one of the burner and oxygen excess rate control [1], [2] and oxygen excess rate control [1], [2] is performed, the control unit 31 controls the stack 11 in step S44. It is determined whether the temperature has reached the target temperature. If the temperature of the stack 11 has reached the target temperature (YES in step S44), in step S45, the control unit 31 turns on a target temperature attainment determination flag indicating that the temperature of the stack 11 has reached the target temperature. Do.
　ステップＳ４６において、制御部３１は、スタック１１の温度及び出力が目標温度及び目標出力に到達したか否かを判断する。スタック１１の温度及び出力が目標温度及び目標出力に到達していなければ（ステップＳ４６でＮＯ）、本処理を終了する。一方、スタック１１の温度及び出力が目標温度及び目標出力に到達していれば（ステップＳ４６でＹＥＳ）、ステップＳ４７において、制御部３１は、スタック昇温制御を終了し、スタック昇温制御終了判定フラグをオンとする。ステップＳ４５の処理で目標温度到達フラグがオンとなり、且つ、ステップＳ４７の処理でスタック昇温制御終了フラグがオンになると、図２のステップＳ１５に示したスタック昇温制御が終了する。 In step S46, the control unit 31 determines whether the temperature and output of the stack 11 have reached the target temperature and the target output. If the temperature and the output of the stack 11 have not reached the target temperature and the target output (NO in step S46), the process ends. On the other hand, if the temperature and the output of stack 11 have reached the target temperature and the target output (YES in step S46), control unit 31 ends the stack temperature increase control in step S47, and the stack temperature increase control end determination Turn on the flag. When the target temperature arrival flag is turned on in the process of step S45 and the stack temperature increase control end flag is turned on in the process of step S47, the stack temperature increase control shown in step S15 of FIG. 2 is completed.
　次に、ステップＳ３４の処理でセル電圧を０．５Ｖ前後に制御することについて、図１６に示す特性図を参照して説明する。図１６は、電流密度（Ａ／ｃｍ2）と、セル電圧（Ｖ）と、出力密度（Ｗ／ｃｍ2）との関係を示している。符号Ｖ１は温度Ｔ１のときの出力電圧を示し、符号Ｖ２は温度Ｔ２（＞Ｔ１）のときの出力電圧を示し、符号Ｖ３は温度Ｔ３（＞Ｔ２）のときの出力電圧を示している。また、符号Ｗ１は温度Ｔ１のときの出力密度（Ｗ／ｃｍ2）を示し、符号Ｗ２は温度Ｔ２のときの出力密度を示し、符号Ｗ３は温度Ｔ３のときの出力密度を示している。 Next, control of the cell voltage to about 0.5 V in the process of step S34 will be described with reference to a characteristic diagram shown in FIG. FIG. 16 shows the relationship between current density (A / cm 2), cell voltage (V) and output density (W / cm 2). The symbol V1 indicates the output voltage at the temperature T1, the symbol V2 indicates the output voltage at the temperature T2 (> T1), and the symbol V3 indicates the output voltage at the temperature T3 (> T2). In addition, the symbol W1 indicates the output density (W / cm 2) at the temperature T1, the symbol W2 indicates the output density at the temperature T2, and the symbol W3 indicates the output density at the temperature T3.
　図１６の特性図から理解されるように、各温度Ｔ１，Ｔ２，Ｔ３において、セル電圧が０．５（Ｖ）付近のときに、単位面積当たりの出力電力、即ち出力密度がピーク値を有している。従って、図４のステップＳ３４に示す処理では、セル電圧を０．５（Ｖ）程度に制御することにより、出力電力を高めて、多くの発熱量を得ることができる。即ち、セル電圧を０．５（Ｖ）程度に制御することにより、スタック１１の昇温効果を向上させることができる。 As understood from the characteristic diagram of FIG. 16, at each temperature T1, T2 and T3, when the cell voltage is around 0.5 (V), the output power per unit area, that is, the output density has a peak value. doing. Therefore, in the process shown in step S34 of FIG. 4, by controlling the cell voltage to about 0.5 (V), the output power can be increased to obtain a large amount of heat generation. That is, by controlling the cell voltage to about 0.5 (V), the temperature increase effect of the stack 11 can be improved.
　次に、図４のステップＳ３９に示したバーナ及び酸素過剰率制御［１］の詳細な処理手順を、図５に示すフローチャートを参照して説明する。初めに、ステップＳ５１において、制御部３１は、目標酸素過剰率を読み込む。この処理では、予めメモリ（図示省略）等に記憶されている目標酸素過剰率（例えば、１．３等）を読み込んで取得する。ここで、メモリ等に記憶されている目標酸素過剰率は、通常運転時における目標酸素過剰率よりも低い数値に設定されている。従って、この目標酸素過剰率を用いてカソード１１ａに供給する酸素量を制御すると、通常運転時よりも少ない酸素（空気）が供給されることになるので、スタック１１の温度は上昇することになる。 Next, the detailed processing procedure of the burner and the excess oxygen ratio control [1] shown in step S39 of FIG. 4 will be described with reference to the flowchart shown in FIG. First, in step S51, the control unit 31 reads a target oxygen excess rate. In this process, a target excess oxygen rate (e.g., 1.3 or the like) stored in advance in a memory (not shown) or the like is read and acquired. Here, the target oxygen excess rate stored in the memory or the like is set to a value lower than the target oxygen excess rate in the normal operation. Therefore, if the target oxygen excess rate is used to control the amount of oxygen supplied to the cathode 11a, less oxygen (air) will be supplied than during normal operation, and the temperature of the stack 11 will rise. .
　ステップＳ５２において、制御部３１は、燃焼バーナ２１の目標出口温度及び供給空気量を読み込む。この処理では、予めメモリ（図示省略）等に記憶されている燃焼バーナ２１の目標出口温度を読み込んで取得する。 In step S52, the control unit 31 reads the target outlet temperature of the combustion burner 21 and the amount of supplied air. In this process, the target outlet temperature of the combustion burner 21 stored in advance in a memory (not shown) or the like is read and acquired.
　ステップＳ５３において、制御部３１は、スタック１１に設けられる電流・電圧センサ４２により、スタック１１の出力電流を検出する。 In step S <b> 53, the control unit 31 detects the output current of the stack 11 by the current / voltage sensor 42 provided on the stack 11.
　ステップＳ５４において、制御部３１は、ステップＳ５３の処理で検出した出力電流に応じた最低の要求酸素量を演算する。具体的には、出力電流が得られるために必要となる酸素量の最低値に、ステップＳ５１の処理で取得した酸素過剰率を乗じた数値を要求酸素量として求める。 In step S54, the control unit 31 calculates the minimum required oxygen amount according to the output current detected in the process of step S53. Specifically, a value obtained by multiplying the minimum value of the amount of oxygen necessary to obtain the output current by the excess oxygen ratio acquired in the process of step S51 is obtained as the required oxygen amount.
　ステップＳ５５において、制御部３１は、ステップＳ５２の処理で取得した燃焼バーナ２１の目標出口温度に基づき、この温度とするために必要とする燃焼バーナ２１の要求燃料量を演算する。即ち、スタック１１の要求酸素量及び燃焼バーナ２１の目標出口温度が決まれば、要求燃料量を求めることができる。 In step S55, based on the target outlet temperature of the combustion burner 21 obtained in the process of step S52, the control unit 31 calculates the required fuel amount of the combustion burner 21 required to achieve this temperature. That is, if the required oxygen amount of the stack 11 and the target outlet temperature of the combustion burner 21 are determined, the required fuel amount can be obtained.
　ステップＳ５６において、制御部３１は、ステップＳ５４の処理で求めた要求酸素量と、ステップＳ５５の処理で求めた要求燃料量とに基づき、空気ブロワ１２より送出する空気量を演算する（この際、燃焼バーナ２１での燃焼によって消費される酸素量を勘案し、燃焼バーナ２１出口の酸素過剰率が、ステップＳ５４の処理で設定された要求酸素量となるように空気量が演算される）。即ち、空気ブロワ１２より送出する空気が燃焼バーナ２１に供給されて、燃焼バーナ２１で燃焼された後に排出されるガス中の酸素量が、ステップＳ５４の処理で求めた要求酸素量となるように、要求カソード空気量を演算する。 In step S56, the control unit 31 calculates the amount of air to be delivered from the air blower 12 based on the required oxygen amount obtained in the process of step S54 and the required fuel amount obtained in the process of step S55 (in this case, In consideration of the amount of oxygen consumed by the combustion in the combustion burner 21, the amount of air is calculated so that the excess oxygen ratio at the outlet of the combustion burner 21 becomes the required oxygen amount set in the process of step S54). That is, the amount of oxygen in the gas discharged after the air delivered from the air blower 12 is supplied to the combustion burner 21 and burned by the combustion burner 21 becomes the required oxygen amount obtained in the process of step S54. , Calculate the required cathode air amount.
　ステップＳ５７において、制御部３１は、ステップＳ５６の処理で求められた空気量とステップＳ５２で読み込んだ供給空気量（実測値）とを比較して、供給空気量が要求カソード空気量になるように、カソード１１ａに供給する空気量を設定し、更に、ステップＳ５８において、燃焼バーナ２１に供給する燃料量を設定し、これらの空気量及び燃料量となるように、空気ブロワ１２及び第２燃料ポンプ２２を制御する。 In step S57, the control unit 31 compares the amount of air obtained in the process of step S56 with the amount of supplied air (actually measured value) read in step S52 so that the amount of supplied air becomes the required amount of cathode air. The amount of air supplied to the cathode 11a is set, and further, the amount of fuel supplied to the combustion burner 21 is set in step S58, and the air blower 12 and the second fuel pump are set so as to have these amounts of air and fuel. Control 22
　こうして、カソード１１ａに供給する空気量及び燃焼バーナ２１に供給する燃料量を、酸素過剰率に基づいて制御することにより、スタック１１を昇温させることができる。つまり、燃焼バーナ２１の燃焼ガスを供給し、且つ、通常運転時よりも低い酸素過剰率とすることにより、スタック１１の温度を急速に昇温することができる。 Thus, the stack 11 can be heated by controlling the amount of air supplied to the cathode 11 a and the amount of fuel supplied to the combustion burner 21 based on the excess oxygen ratio. That is, by supplying the combustion gas of the combustion burner 21 and setting the oxygen excess rate lower than that during normal operation, the temperature of the stack 11 can be rapidly raised.
　次に、図４のステップＳ４０に示したバーナ及び酸素過剰率制御［２］の詳細な処理手順を、図６に示すフローチャートを参照して説明する。この処理では、バーナ及び酸素過剰率制御［１］と異なり、スタック１１が目標温度に到達しているので、スタック１１の出口と入口の温度差ΔＴ（出口温度－入口温度）、或いはスタック１１の出口温度に基づいて、スタック１１の温度が目標温度を維持するように、燃焼バーナ２１及び酸素過剰率を制御する。 Next, the detailed processing procedure of the burner and the excess oxygen ratio control [2] shown in step S40 of FIG. 4 will be described with reference to the flowchart shown in FIG. In this process, unlike the burner and oxygen excess ratio control [1], since the stack 11 has reached the target temperature, the temperature difference ΔT (outlet temperature−inlet temperature) between the outlet and the inlet of the stack 11 or Based on the outlet temperature, the combustion burner 21 and the excess oxygen ratio are controlled so that the temperature of the stack 11 maintains the target temperature.
　初めに、ステップＳ６１において、制御部３１は、スタック１１の出口温度と入口温度との温度差ΔＴ、或いは、カソード１１ａの出口温度を検出する。 First, in step S61, the control unit 31 detects the temperature difference ΔT between the outlet temperature and the inlet temperature of the stack 11 or the outlet temperature of the cathode 11a.
　ステップＳ６２において、制御部３１は、燃焼バーナ２１の目標出口温度を読み込む。この処理では、図５のステップＳ５２の処理と同様に、メモリ等に記憶されている目標出口温度を読み込んで取得する。 In step S62, the control unit 31 reads the target outlet temperature of the combustion burner 21. In this process, as in the process of step S52 of FIG. 5, the target outlet temperature stored in the memory or the like is read and acquired.
　ステップＳ６３において、制御部３１は、カソード１１ａに供給する酸素過剰燃焼ガス量、即ち、燃焼バーナ２１で燃焼した後に排出される酸素過剰ガスの流量（以下、供給ガス量という）を演算する。そして、制御部３１は、以後の処理で、カソード１１ａに供給するガス量が供給ガス量となるように制御を行なう。 In step S63, the control unit 31 calculates the amount of excess oxygen combustion gas supplied to the cathode 11a, that is, the flow amount of excess oxygen gas discharged after the combustion with the combustion burner 21 (hereinafter referred to as the amount of supply gas). Then, the control unit 31 performs control such that the amount of gas supplied to the cathode 11 a becomes the amount of supplied gas in the subsequent processing.
　具体的には、ステップＳ６１の処理で温度差ΔＴを検出した場合には、ΔＴ＞０であれば供給ガス量を所定量だけ増加させ、ΔＴ＜０であれば供給ガス量を所定量だけ減少させることにより、温度差ΔＴがゼロに近づくように制御する。また、ステップＳ６１で出口温度を検出した場合には、（出口温度）＞（目標温度）であれば供給ガス量を所定量だけ増加させ、（出口温度）＜（目標温度）であれば供給ガス量を所定量だけ減少させることにより、スタック１１の温度が目標温度になるように制御する。 Specifically, when the temperature difference ΔT is detected in the process of step S61, the supply gas amount is increased by a predetermined amount if ΔT> 0, and the supply gas amount is decreased by a predetermined amount if ΔT <0. The temperature difference .DELTA.T is controlled so as to approach zero by performing the control. When the outlet temperature is detected in step S61, if (outlet temperature)> (target temperature), the amount of supplied gas is increased by a predetermined amount, and if (outlet temperature) <(target temperature) the supplied gas By reducing the amount by a predetermined amount, the temperature of the stack 11 is controlled to be the target temperature.
　ステップＳ６４において、制御部３１は、ステップＳ６３の処理で求めた供給ガス量に基づいて、空気ブロワ１２より送出する要求カソード空気量を演算する。即ち、空気ブロワ１２より送出する空気が燃焼バーナ２１に供給され、且つ、燃焼バーナ２１で燃焼した後に排出されるガス量が、ステップＳ６３の処理で求めた供給ガス量となるように、空気ブロワ１２が送出する空気量を演算する。 In step S64, the control unit 31 calculates the required cathode air amount to be sent from the air blower 12 based on the supply gas amount obtained in the process of step S63. That is, the air blower 12 is supplied with the air delivered from the air blower 12 and supplied to the combustion burner 21 so that the amount of gas discharged after burning by the combustion burner 21 becomes the amount of supplied gas obtained in the process of step S63. 12 calculates the amount of air to be delivered.
　ステップＳ６５において、制御部３１は、ステップＳ６２の処理で取得した燃焼バーナ２１の目標出口温度に基づき、この温度とするために必要とする燃焼バーナ２１の要求燃料量を演算する。 In step S65, based on the target outlet temperature of the combustion burner 21 obtained in the process of step S62, the control unit 31 calculates the required fuel amount of the combustion burner 21 required to achieve this temperature.
　ステップＳ６６において、制御部３１は、ステップＳ６４の処理で求められた空気量をカソード１１ａに供給する空気量として設定し、更に、ステップＳ６７において、燃焼バーナ２１に供給する燃料量を設定し、これらの空気量及び燃料量となるように、空気ブロワ１２及び第２燃料ポンプ２２を制御する。 In step S66, the control unit 31 sets the amount of air obtained in the process of step S64 as the amount of air supplied to the cathode 11a, and further sets the amount of fuel supplied to the combustion burner 21 in step S67. The air blower 12 and the second fuel pump 22 are controlled so that the amount of air and the amount of fuel become as follows.
　こうして、カソード１１ａに供給する空気量及び燃焼バーナ２１に供給する燃料量を、酸素過剰率に基づいて制御することにより、スタック１１の温度を目標温度に保持することができる。 Thus, the temperature of the stack 11 can be maintained at the target temperature by controlling the amount of air supplied to the cathode 11a and the amount of fuel supplied to the combustion burner 21 based on the oxygen excess rate.
　次に、図４のステップＳ４２に示した酸素過剰率制御［１］の詳細な処理手順を、図７に示すフローチャートを参照して説明する。初めに、ステップＳ７１において、制御部３１は、目標酸素過剰率を読み込む。この処理では、予めメモリ（図示省略）等に記憶されている目標酸素過剰率を読み込んで取得する。この酸素過剰率は、スタック１１の通常運転時の酸素過剰率よりも低い数値に設定されている。 Next, the detailed processing procedure of the excess oxygen ratio control [1] shown in step S42 of FIG. 4 will be described with reference to the flowchart shown in FIG. First, in step S71, the control unit 31 reads a target oxygen excess rate. In this process, the target oxygen excess rate stored in advance in a memory (not shown) or the like is read and acquired. The oxygen excess rate is set to a lower value than the oxygen excess rate during normal operation of the stack 11.
　ステップＳ７２において、制御部３１は、スタック１１に設けられる電流・電圧センサ４２により、スタック１１の出力電流を検出する。 In step S <b> 72, the control unit 31 detects the output current of the stack 11 by the current / voltage sensor 42 provided in the stack 11.
　ステップＳ７３において、制御部３１は、ステップＳ７２の処理で検出した出力電流に応じた最低の要求酸素量を演算する。具体的には、出力電流が得られるために必要となる酸素量の最低値に、ステップＳ７１の処理で取得した酸素過剰率を乗じた数値を要求酸素量として求める。 In step S73, the control unit 31 calculates the minimum required oxygen amount according to the output current detected in the process of step S72. Specifically, a value obtained by multiplying the minimum value of the amount of oxygen necessary to obtain the output current by the excess oxygen ratio acquired in the process of step S71 is obtained as the required oxygen amount.
　ステップＳ７４において、制御部３１は、ステップＳ７３の処理で求めた要求酸素量に基づいて、空気ブロワ１２より送出する空気量を演算する。即ち、要求酸素量をカソード１１ａに供給するために必要な空気量を演算する。 In step S74, the control unit 31 calculates the amount of air to be delivered from the air blower 12 based on the required oxygen amount obtained in the process of step S73. That is, the amount of air required to supply the required oxygen amount to the cathode 11a is calculated.
　ステップＳ７５において、制御部３１は、ステップＳ７４の処理で求められた空気量をカソード１１ａに供給する空気量として設定し、この空気となるように、空気ブロワ１２を制御する。 In step S75, the control unit 31 sets the amount of air obtained in the process of step S74 as the amount of air supplied to the cathode 11a, and controls the air blower 12 to become this air.
　こうして、カソード１１ａに供給する空気量を酸素過剰率に基づいて制御することにより、スタック１１を昇温させることができる。上述したように、目標酸素過剰率は通常運転時の酸素過剰率よりも低く設定されているので、カソード１１ａに供給される酸素量（空気量）は通常運転時よりも少なくなり、冷却効果が低減して、スタック１１を昇温することができる。 Thus, the stack 11 can be heated by controlling the amount of air supplied to the cathode 11 a based on the oxygen excess rate. As described above, since the target excess oxygen ratio is set to be lower than the excess oxygen ratio in the normal operation, the amount of oxygen (the amount of air) supplied to the cathode 11a becomes smaller than in the normal operation, and the cooling effect is reduced. The temperature can be reduced to raise the temperature of the stack 11.
　次に、図４のステップＳ４３に示した酸素過剰率制御［２］の詳細な処理手順を、図８に示すフローチャートを参照して説明する。この処理では、酸素過剰率制御［１］と異なり、スタック１１が目標温度に到達しているので、スタック１１の出口と入口の温度差ΔＴ（出口温度－入口温度）、或いはスタック１１の出口温度に基づいて、スタック１１の温度が目標温度を維持するように、酸素過剰率を制御する。 Next, the detailed processing procedure of the excess oxygen ratio control [2] shown in step S43 of FIG. 4 will be described with reference to the flowchart shown in FIG. In this process, unlike the excess oxygen ratio control [1], since the stack 11 has reached the target temperature, the temperature difference ΔT (outlet temperature−inlet temperature) between the outlet and the inlet of the stack 11 or the outlet temperature of the stack 11 Based on the control of the excess oxygen rate so that the temperature of the stack 11 maintains the target temperature.
　初めに、ステップＳ８１において、制御部３１は、スタック１１の出口温度と入口温度との温度差ΔＴ、或いは、カソード１１ａの出口温度を検出する。 First, in step S81, the control unit 31 detects a temperature difference ΔT between the outlet temperature of the stack 11 and the inlet temperature, or the outlet temperature of the cathode 11a.
　ステップＳ８２において、制御部３１は、空気ブロワ１２より送出する要求カソード空気量を演算する。具体的には、ステップＳ８１の処理で温度差ΔＴを検出した場合には、ΔＴ＞０であれば供給空気量を所定量だけ増加させ、ΔＴ＜０であれば供給空気量を所定量だけ減少させることにより、温度差ΔＴがゼロに近づくように制御する。また、ステップＳ８１で出口温度を検出した場合には、（出口温度）＞（目標温度）であれば供給空気量を所定量だけ増加させ、（出口温度）＜（目標温度）であれば供給空気量を所定量だけ減少させることにより、スタック１１の温度が目標温度に近づくように制御する。 In step S82, the control unit 31 calculates the required cathode air amount to be delivered from the air blower 12. Specifically, if the temperature difference ΔT is detected in the process of step S81, the supplied air amount is increased by a predetermined amount if ΔT> 0, and the supplied air amount is decreased by a predetermined amount if ΔT <0. The temperature difference .DELTA.T is controlled so as to approach zero by performing the control. When the outlet temperature is detected in step S81, if (outlet temperature)> (target temperature), the supplied air amount is increased by a predetermined amount, and if (outlet temperature) <(target temperature), the supplied air By reducing the amount by a predetermined amount, the temperature of the stack 11 is controlled to approach the target temperature.
　ステップＳ８３において、制御部３１は、ステップＳ８２の処理で求められた空気量をカソード１１ａに供給する空気量として設定し、この空気量となるように、空気ブロワ１２を制御する。 In step S83, the control unit 31 sets the amount of air obtained in the process of step S82 as the amount of air supplied to the cathode 11a, and controls the air blower 12 to achieve this amount of air.
　こうして、カソード１１ａに供給する空気量を酸素過剰率に基づいて制御することにより、スタック１１を目標温度に維持することができる。 Thus, the stack 11 can be maintained at the target temperature by controlling the amount of air supplied to the cathode 11a based on the oxygen excess rate.
　このようにして、本実施形態に係る燃料電池システム１００では、スタック１１のセル電圧と、カソード１１ａに供給するガスの酸素過剰率と、燃焼バーナ２１より出力される燃焼ガスと、のうちの少なくとも一つを制御することにより、発電可能温度まで昇温されたスタック１１を目標出力での運転に必要な目標温度まで昇温させている。それゆえ、スタック１１の昇温が促進され、迅速に目標温度または目標出力に到達させることができる。従って、例えば車両に搭載する場合のように、即応性が要求されるスタックの場合に極めて有用である。また、昇温に要するエネルギー量を低減することができる。 Thus, in the fuel cell system 100 according to the present embodiment, at least one of the cell voltage of the stack 11, the excess oxygen ratio of the gas supplied to the cathode 11a, and the combustion gas output from the combustion burner 21. By controlling one, the stack 11 raised to the power generation possible temperature is raised to the target temperature necessary for the operation at the target output. Therefore, the temperature rise of the stack 11 is promoted, and the target temperature or the target output can be quickly reached. Therefore, it is extremely useful in the case of a stack where quick responsiveness is required, for example, when mounted on a vehicle. In addition, the amount of energy required to raise the temperature can be reduced.
　また、燃料電池システム１００に要求される目標出力が図１６に示した所定値Ｘ１を下回る場合には、燃焼バーナ２１を作動させずにスタック１１を昇温する。即ち、カソード１１ａに供給するガスの酸素過剰率制御、及びスタック１１のセル電圧制御のうちの少なくとも一つを制御し、燃焼バーナ２１を停止させた状態で、燃料電池を目標温度まで昇温する。従って、消費するエネルギー量を低減することができる。 Further, when the target output required for the fuel cell system 100 falls below the predetermined value X1 shown in FIG. 16, the stack 11 is heated without operating the combustion burners 21. That is, at least one of the oxygen excess rate control of the gas supplied to the cathode 11a and the cell voltage control of the stack 11 is controlled to raise the temperature of the fuel cell to the target temperature with the combustion burner 21 stopped. . Therefore, the amount of energy consumed can be reduced.
　更に、セル電圧を制御する際に、燃料電池出力がピークとなる電圧値に対して、一定の割合となる電圧値、例えば、セル電圧を０．５（Ｖ）付近とするように制御するので、効率良くスタック１１を目標温度まで昇温させることができる。 Furthermore, when the cell voltage is controlled, the voltage value at which the fuel cell output reaches a peak is controlled to be a constant ratio, for example, the cell voltage to be around 0.5 (V). The stack 11 can be efficiently heated to the target temperature.
（第２実施形態）
　図９は、本実施形態に係る燃料電池システム１００ａの構成を示すブロック図である。燃料電池システム１００ａは、第１実施形態の構成と対比して、次の点で相違している：（１）スタック１１（１段目スタック）の後段にカソード３２ａ及びアノード３２ｂを有する２段目スタック３２が設けられている；（２）１段目スタック（第１燃料電池）１１のカソード１１ａ出口と、２段目スタック（第２燃料電池）３２のカソード３２ａ入口を接続する流路に、冷却空気導入通路（バイパス流路）３３が接続されており、冷却空気導入通路３３を経由して空気ブロワ１２より送出される空気の一部がカソード３２ａに導入される。なお、冷却空気導入通路３３には、カソード３２ａに導入する空気量を調整するための冷却空気流量制御装置３４が設けられている。 Second Embodiment
FIG. 9 is a block diagram showing a configuration of a fuel cell system 100a according to the present embodiment. The fuel cell system 100a differs from the configuration of the first embodiment in the following points: (1) Second stage having a cathode 32a and an anode 32b at the rear stage of the stack 11 (first stage stack) The stack 32 is provided; (2) in a flow path connecting the outlet of the cathode 11 a of the first stage stack (first fuel cell) 11 and the inlet of the cathode 32 a of the second stage stack (second fuel cell) 32 The cooling air introduction passage (bypass passage) 33 is connected, and a part of the air delivered from the air blower 12 via the cooling air introduction passage 33 is introduced into the cathode 32 a. The cooling air introduction passage 33 is provided with a cooling air flow control device 34 for adjusting the amount of air introduced into the cathode 32a.
　また、２段目スタック３２には、入口側の温度を測定する入口温度センサ５１ａと、出口側の温度を測定する出口温度センサ５１ｂと、出力電流及び電圧を測定する電流・電圧センサ５２が設けられている。それ以外の構成は、図１に示した構成と同様であるので、同一符号を付して構成説明を省略する。 The second stage stack 32 is provided with an inlet temperature sensor 51a for measuring the temperature on the inlet side, an outlet temperature sensor 51b for measuring the temperature on the outlet side, and a current / voltage sensor 52 for measuring the output current and voltage. It is done. The other configuration is the same as the configuration shown in FIG. 1, so the same reference numerals are given and the description of the configuration is omitted.
次に、燃料電池システム１００ａの作用を、図１０～図１４に示すフローチャートを参照して説明する。図１０は、燃料電池システム１００ａの起動時におけるスタックの昇温操作の全体の処理手順を示すフローチャートである。 Next, the operation of the fuel cell system 100a will be described with reference to the flowcharts shown in FIG. 10 to FIG. FIG. 10 is a flowchart showing the entire processing procedure of the temperature raising operation of the stack at the time of startup of the fuel cell system 100a.
　初めに、ステップＳ１０１において、制御部３１は、１段目スタック１１を起動するか否かを判断する。１段目スタック１１を起動する場合には（ステップＳ１０１でＹＥＳ）、ステップＳ１０２において、制御部３１は、燃焼バーナ２１による１段目スタック１１の加熱が終了したか否かを判断する。１段目スタック１１の加熱が終了していなければ（ステップＳ１０２でＮＯ）、ステップＳ１０３において、制御部３１は、燃焼バーナ２１による１段目スタック１１の加熱制御を継続して行う。スタック加熱制御の詳細は、前述した図３に示したフローチャートと同様の処理であるので説明を省略する。その後、ステップＳ１０４に処理を進める。 First, in step S101, the control unit 31 determines whether to activate the first stage stack 11. When the first stage stack 11 is activated (YES in step S101), the control unit 31 determines in step S102 whether the heating of the first stage stack 11 by the combustion burner 21 is finished. If the heating of the first stage stack 11 is not completed (NO in step S102), the control unit 31 continues the heating control of the first stage stack 11 by the combustion burner 21 in step S103. The details of the stack heating control are the same processing as the flowchart shown in FIG. Thereafter, the process proceeds to step S104.
　ステップＳ１０４において、制御部３１は、１段目スタック１１の昇温制御が終了しているか否かを判断する。１段目スタック１１の昇温制御が終了していなければ（ステップＳ１０４でＮＯ）、ステップＳ１０５において、制御部３１は、１段目スタック１１の昇温制御を行う。１段目スタック１１の昇温制御は、図４に示したフローチャートと同様の処理であるので説明を省略する。その後、ステップＳ１０６に処理を進める。 In step S104, the control unit 31 determines whether the temperature increase control of the first-stage stack 11 has ended. If the temperature increase control of the first stage stack 11 is not completed (NO in step S104), the control unit 31 performs the temperature increase control of the first stage stack 11 in step S105. The temperature increase control of the first-stage stack 11 is the same processing as the flowchart shown in FIG. Thereafter, the process proceeds to step S106.
　ステップＳ１０６において、制御部３１は、２段目スタック３２の第１昇温制御が必要であるか否かを判断する。なお、第１昇温制御とは、２段目スタック３２が発電可能温度に到達するまで昇温する制御のことである。２段目スタック３２が発電可能温度に到達しておらず、２段目スタック３２の第１昇温制御が必要である場合には（ステップＳ１０６でＹＥＳ）、ステップＳ１０７において、制御部３１は、２段目スタック３２の第１昇温制御を実行する。第１昇温制御の詳細については、図１１を参照して後述する。 In step S106, the control unit 31 determines whether the first temperature increase control of the second stack 32 is necessary. The first temperature raising control is control for raising the temperature of the second-stage stack 32 until it reaches the power generation possible temperature. If the second stage stack 32 has not reached the power generation possible temperature and the first temperature increase control of the second stage stack 32 is required (YES in step S106), the control unit 31 determines in step S107 that The first temperature increase control of the second stage stack 32 is performed. The details of the first temperature increase control will be described later with reference to FIG.
　一方、２段目スタック３２の第１昇温制御が必要でない場合（ステップＳ１０６でＮＯ）、或いは２段目スタック３２の第１昇温制御が終了した場合には、ステップＳ１０８において、制御部３１は、２段目スタックの第２昇温制御が必要であるか否かを判断する。ここで、第２昇温制御とは、２段目スタック３２が発電可能温度に到達した後、更に通常運転時の温度まで昇温させる制御のことである。２段目スタック３２が通常運転時の温度に到達しておらず、２段目スタック３２の第２昇温制御が必要である場合（ステップＳ１０８でＹＥＳ）には、ステップＳ１０９において、制御部３１は、２段目スタック３２の第２昇温制御を実行する。第２昇温制御の詳細については、図１３を参照して後述する。 On the other hand, when the first temperature increase control of the second stage stack 32 is not necessary (NO in step S106) or when the first temperature increase control of the second stage stack 32 is completed, the control unit 31 is performed in step S108. It is determined whether or not the second temperature increase control of the second stage stack is necessary. Here, the second temperature increase control is control to further increase the temperature to the temperature during normal operation after the second-stage stack 32 reaches the power generation possible temperature. If the second stage stack 32 has not reached the temperature at the time of normal operation and the second temperature increase control of the second stage stack 32 is required (YES in step S108), the controller 31 in step S109. Executes the second temperature increase control of the second stage stack 32. The details of the second temperature increase control will be described later with reference to FIG.
　２段目スタック３２の第２昇温制御が必要でない場合（ステップＳ１０８でＮＯ）、或いは第２昇温制御が終了した場合には、本処理をリターンする。 When the second temperature increase control of the second stage stack 32 is not necessary (NO in step S108) or when the second temperature increase control ends, the present process returns.
　次に、図１０のステップＳ１０７に示した２段目スタック３２の第１昇温制御の処理手順について、図１１に示すフローチャートを参照して説明する。初めに、ステップＳ１１１において、制御部３１は、メモリ（図示省略）等に記憶されている目標出力（１段目スタック１１と２段目スタック３２の合計の目標出力）を読み込む。 Next, the procedure of the first temperature increase control of the second stack 32 shown in step S107 of FIG. 10 will be described with reference to the flowchart shown in FIG. First, in step S111, the control unit 31 reads a target output (total target output of the first stack 11 and the second stack 32) stored in a memory (not shown) or the like.
　ステップＳ１１２において、制御部３１は、１段目スタック１１のみの運転で目標出力を得ることが可能であるか否かを判断する。１段目スタック１１のみの運転で目標出力を得ることが可能であれば（ステップＳ１１２でＹＥＳ）、ステップＳ１１６において、制御部３１は、２段目スタック３２の第１昇温制御不必要判定フラグをオンとする。 In step S112, the control unit 31 determines whether or not it is possible to obtain the target output by the operation of only the first-stage stack 11. If it is possible to obtain the target output by the operation of only the first stage stack 11 (YES in step S112), the control unit 31 determines the first temperature increase control unnecessary flag of the second stage stack 32 in step S116. Turn on.
　一方、１段目スタック１１のみの運転で目標出力を得ることが可能でなければ（ステップＳ１１２でＮＯ）、ステップＳ１１３において、制御部３１は、２段目スタック３２に設けられた入口温度センサ５１ａと出口温度センサ５１ｂにより、２段目スタック３２の温度（例えば、入口温度と出口温度の平均値）を検出する。 On the other hand, if it is not possible to obtain the target output by the operation of only the first-stage stack 11 (NO in step S112), the controller 31 controls the inlet temperature sensor 51a provided in the second-stage stack 32 in step S113. The outlet temperature sensor 51b detects the temperature of the second stage stack 32 (for example, the average value of the inlet temperature and the outlet temperature).
　ステップＳ１１４において、制御部３１は、２段目スタック３２の昇温が必要であるか否かを判断する。具体的には、ステップＳ１１３の処理にて２段目スタック３２の温度が発電可能温度に達している場合には、第１昇温制御は不要となりステップＳ１１６に処理を進める。一方、ステップＳ１１３の処理にて２段目スタック３２の温度が発電可能温度に達していない場合には、第１昇温制御を行なう必要があるので、ステップＳ１１５に処理を進める。 In step S114, the control unit 31 determines whether it is necessary to raise the temperature of the second stack 32. Specifically, when the temperature of the second stack 32 has reached the power generation possible temperature in the process of step S113, the first temperature increase control is unnecessary, and the process proceeds to step S116. On the other hand, when the temperature of the second stack 32 has not reached the power generation possible temperature in the process of step S113, it is necessary to perform the first temperature increase control, so the process proceeds to step S115.
　ステップＳ１１５において、制御部３１は、バーナ及び酸素過剰率制御［３］を実行する。バーナ及び酸素過剰率制御［３］の詳細については図１２に示すフローチャートを参照して後述する。 In step S115, the control unit 31 executes burner and oxygen excess ratio control [3]. Details of the burner and the excess oxygen ratio control [3] will be described later with reference to the flowchart shown in FIG.
　次に、図１１のステップＳ１１５に示したバーナ及び酸素過剰率制御［３］の詳細な処理手順について、図１２に示すフローチャートを参照して説明する。 Next, the detailed processing procedure of the burner and the excess oxygen ratio control [3] shown in step S115 of FIG. 11 will be described with reference to the flowchart shown in FIG.
　初めに、ステップＳ１２１において、制御部３１は、１段目スタック１１に設けられる入口温度センサ４１ａで測定される入口温度と出口温度センサ４１ｂで測定される出口温度との温度差ΔＴ（出口温度－入口温度）、或いは、カソード１１ａの出口温度を検出する。 First, in step S121, the control unit 31 sets the temperature difference .DELTA.T between the inlet temperature measured by the inlet temperature sensor 41a provided in the first stage stack 11 and the outlet temperature measured by the outlet temperature sensor 41b (outlet temperature- The inlet temperature) or the outlet temperature of the cathode 11a is detected.
　ステップＳ１２２において、制御部３１は、目標出力と１段目スタック１１の現在の出力（現状出力）との関係から、これらの差分値を演算する。 In step S122, the control unit 31 calculates these difference values from the relationship between the target output and the current output (current output) of the first stage stack 11.
　ステップＳ１２３において、制御部３１は、ステップＳ１２２の処理で求めた差分値に基づき、燃焼バーナ２１を起動する必要が有るか否かを判断する。具体的には、制御部３１は、差分値が一定値よりも大きい場合には、燃焼バーナ２１を起動させる必要があると判断する。燃焼バーナ２１を起動させる必要がある場合には（ステップＳ１２３でＹＥＳ）、ステップＳ１２４に処理を進める。一方、燃焼バーナ２１を起動させる必要がない場合には（ステップＳ１２３でＮＯ）、ステップＳ１３０に処理を進める。 In step S123, the control unit 31 determines whether it is necessary to activate the combustion burner 21 based on the difference value obtained in the process of step S122. Specifically, the control unit 31 determines that it is necessary to start the combustion burner 21 when the difference value is larger than a predetermined value. If it is necessary to activate the combustion burners 21 (YES in step S123), the process proceeds to step S124. On the other hand, when it is not necessary to start the combustion burner 21 (NO in step S123), the process proceeds to step S130.
　ステップＳ１２４において、制御部３１は、燃焼バーナ２１の目標出口温度を読み込む。この処理では、メモリ等に記憶されている目標出口温度を読み込んで取得する。具体的には、図１７に示すように、差分値（目標出力と現状出力の差分）と燃焼バーナ２１の目標出口温度との関係を示す特性曲線がメモリ等に記憶されている。制御部３１は、ステップＳ１２２の処理で求められた差分値を図１７の特性曲線に当てはめることにより、燃焼バーナ２１の目標出口温度を取得する。 In step S124, the control unit 31 reads the target outlet temperature of the combustion burner 21. In this process, the target outlet temperature stored in the memory or the like is read and acquired. Specifically, as shown in FIG. 17, a characteristic curve indicating the relationship between the difference value (the difference between the target output and the current output) and the target outlet temperature of the combustion burner 21 is stored in a memory or the like. The control unit 31 obtains the target outlet temperature of the combustion burner 21 by applying the difference value obtained in the process of step S122 to the characteristic curve of FIG.
　ステップＳ１２５において、制御部３１は、１段目スタック１１のカソード１１ａに供給する酸素過剰燃焼ガス量、即ち、燃焼バーナ２１で燃焼した後に排出される酸素過剰ガスの流量（以下、「供給ガス量」という）を演算して、この供給ガス量となるように空気ブロワ１２を制御する。 In step S125, the control unit 31 controls the amount of excess oxygen combustion gas supplied to the cathode 11a of the first-stage stack 11, that is, the flow amount of excess oxygen gas discharged after combustion by the combustion burner 21 (hereinafter referred to as “supply gas amount And the air blower 12 is controlled to achieve this supplied gas amount.
　具体的には、ステップＳ１２１の処理で温度差ΔＴを検出した場合には、ΔＴ＞０であれば供給ガス量を所定量だけ増加させ、ΔＴ＜０であれば供給ガス量を所定量だけ減少させることにより、温度差ΔＴがゼロに近づくように制御する。また、ステップＳ１２１で出口温度を検出した場合には、（出口温度）＞（目標温度）であれば供給ガス量を所定量だけ増加させ、（出口温度）＜（目標温度）であれば供給ガス量を所定量だけ減少させることにより、１段目スタック１１の温度が目標温度になるように制御する。 Specifically, when the temperature difference ΔT is detected in the process of step S121, the supply gas amount is increased by a predetermined amount if ΔT> 0, and the supply gas amount is decreased by a predetermined amount if ΔT <0. The temperature difference .DELTA.T is controlled so as to approach zero by performing the control. When the outlet temperature is detected in step S121, if (outlet temperature)> (target temperature), the supplied gas amount is increased by a predetermined amount, and if (outlet temperature) <(target temperature), the supplied gas By reducing the amount by a predetermined amount, the temperature of the first stage stack 11 is controlled to be the target temperature.
　ステップＳ１２６において、制御部３１は、ステップＳ１２５の処理で求めた供給ガス量に基づいて、空気ブロワ１２より送出する要求カソード空気量を演算する。即ち、空気ブロワ１２より送出する空気が燃焼バーナ２１及び１段目スタック１１を経由して、２段目スタック１１に供給されるガス量が、ステップＳ１２５の処理で求めた供給ガス量となるように、空気ブロワ１２が送出する空気量を演算する。 In step S126, the control unit 31 calculates the required cathode air amount to be delivered from the air blower 12 based on the supply gas amount obtained in the process of step S125. That is, the amount of gas supplied from the air blower 12 to the second stage stack 11 via the combustion burner 21 and the first stage stack 11 is equal to the amount of gas supplied in the process of step S125. Then, the amount of air delivered by the air blower 12 is calculated.
　ステップＳ１２７において、制御部３１は、ステップＳ１２４の処理で取得した燃焼バーナ２１の目標出口温度に基づき、この温度とするために必要とする燃焼バーナ２１の要求燃料量を演算する。具体的には、２段目スタック３２の温度が発電可能温度に到達していない場合には、システムに要求される目標出力が高いほど、燃焼バーナ２１より出力する燃焼ガス温度を高くするように制御する。 In step S127, based on the target outlet temperature of the combustion burner 21 acquired in the process of step S124, the control unit 31 calculates the required fuel amount of the combustion burner 21 required to achieve this temperature. Specifically, when the temperature of the second stage stack 32 does not reach the power generation possible temperature, the temperature of the combustion gas output from the combustion burner 21 is increased as the target output required for the system increases. Control.
　ステップＳ１２８において、制御部３１は、ステップＳ１２６の処理で求められた空気量をカソード１１ａに供給する空気量として設定し、更に、ステップＳ１２９において、燃焼バーナ２１に供給する燃料量を設定し、これらの空気量及び燃料量となるように、空気ブロワ１２及び第２燃料ポンプ２２を制御する。 In step S128, the control unit 31 sets the amount of air obtained in the process of step S126 as the amount of air supplied to the cathode 11a, and further sets the amount of fuel supplied to the combustion burner 21 in step S129. The air blower 12 and the second fuel pump 22 are controlled so that the amount of air and the amount of fuel become as follows.
　一方、燃焼バーナ２１を起動させる必要がない場合には（ステップＳ１２３でＮＯ）、ステップＳ１３０において、制御部３１は、目標出力に基づいて、空気ブロワ１２より送出する要求カソード空気量を演算する。この処理では、燃焼バーナ２１を停止させた状態で、ステップＳ１２５に示した処理と同様の処理を実施する。 On the other hand, when it is not necessary to start the combustion burner 21 (NO in step S123), in step S130, the control unit 31 calculates the required cathode air amount to be sent from the air blower 12 based on the target output. In this process, with the combustion burner 21 stopped, the same process as the process shown in step S125 is performed.
　具体的には、ステップＳ１２１の処理で温度差ΔＴを検出した場合には、ΔＴ＞０であれば供給ガス量（酸素量に対応）を所定量だけ増加させ、ΔＴ＜０であれば供給ガス量を所定量だけ減少させることにより、温度差ΔＴがゼロに近づくように制御する。また、ステップＳ１２１で出口温度を検出した場合には、（出口温度）＞（目標温度）であれば供給ガス量（酸素量に対応）を所定量だけ増加させ、（出口温度）＜（目標温度）であれば供給ガス量を所定量だけ減少させることにより、１段目スタック１１の温度が目標温度になるように制御する。 Specifically, when the temperature difference ΔT is detected in the process of step S121, the amount of supplied gas (corresponding to the amount of oxygen) is increased by a predetermined amount if ΔT> 0, and the supplied gas if ΔT <0. By reducing the amount by a predetermined amount, the temperature difference ΔT is controlled to approach zero. When the outlet temperature is detected in step S121, if (outlet temperature)> (target temperature), the amount of supplied gas (corresponding to the amount of oxygen) is increased by a predetermined amount, and (outlet temperature) <(target temperature) In the case of), the temperature of the first stage stack 11 is controlled to be the target temperature by reducing the amount of supplied gas by a predetermined amount.
　更に、ステップＳ１３１において、制御部３１は、ステップＳ１３０の処理で求めた空気量となるように、空気ブロワ１２より送出する空気量を設定する。 Further, in step S131, the control unit 31 sets the amount of air to be delivered from the air blower 12 so as to be the amount of air obtained in the process of step S130.
　こうして、１段目スタック１１のカソード１１ａに供給するガス量及び燃焼バーナ２１に供給する燃料量を、酸素過剰率に基づいて制御することにより、１段目スタック１１のカソード１１ａから２段目スタック３２のカソード３２ａに流入する１段目スタック作動温度とほぼ同一温度のガス流量が増加するため、目標温度（発電可能温度）まで迅速に２段目スタック３２を昇温させることができることとなる。 Thus, the amount of gas supplied to the cathode 11a of the first-stage stack 11 and the amount of fuel supplied to the combustion burner 21 are controlled based on the excess oxygen ratio, whereby the second-stage stack from the cathode 11a of the first-stage stack 11 is performed. Since the gas flow rate at substantially the same temperature as the first stage stack operating temperature flowing into the cathode 32a of 32 increases, the second stage stack 32 can be rapidly heated to the target temperature (power generation possible temperature).
　次に、図１０のステップＳ１０９に示した２段目スタック３２の第２昇温制御の詳細な処理手順について、図１３に示すフローチャートを参照して説明する。初めに、図１３のステップＳ１４１において、制御部３１は、システムに要求される目標出力を、例えば、車載用のシステムであれば、アクセルの操作量等から演算し、その結果を目標出力として読み込む。 Next, a detailed processing procedure of the second temperature increase control of the second stack 32 shown in step S109 of FIG. 10 will be described with reference to the flowchart shown in FIG. First, in step S141 of FIG. 13, the control unit 31 calculates the target output required of the system, for example, from the amount of operation of the accelerator in the case of an on-vehicle system, and reads the result as the target output. .
　ステップＳ１４２において、制御部３１は、燃料電池システム１００ａの現状出力を検出する。現状出力は、１段目スタック１１に設けられた電流・電圧センサ４２と、２段目スタック３２に設けられた電流・電圧センサ５２と、で検出される出力電流と電圧に基づいて求めることができる。更に、制御部３１は、目標出力と現状出力の差分を求め、これを差分値Ａとする。ステップＳ１４３において、制御部３１は、２段目スタック３２の温度を検出する。この処理では、２段目スタック３２に設けられる入口温度センサ５１ａと出口温度センサ５１ｂにより、例えば平均値としてスタック温度を検出する。 In step S142, the control unit 31 detects the current output of the fuel cell system 100a. The current output can be determined based on the output current and voltage detected by the current / voltage sensor 42 provided in the first stage stack 11 and the current / voltage sensor 52 provided in the second stage stack 32. it can. Furthermore, the control unit 31 obtains the difference between the target output and the current output, and sets this as the difference value A. In step S143, the control unit 31 detects the temperature of the second stage stack 32. In this process, the stack temperature is detected as an average value, for example, by the inlet temperature sensor 51a and the outlet temperature sensor 51b provided in the second stage stack 32.
　ステップＳ１４４において、制御部３１は、２段目スタック３２を昇温する必要があるか否かを判断する。例えば、２段目スタック３２の温度が所定値以上であれば、差分値Ａが所定値以上であっても目標出力となる電力を発電することができるので、このような場合には、制御部３１は２段目スタック３２を昇温する必要は無いと判断する。２段目スタック３２を昇温する必要が有る場合には（ステップＳ１４４で必要）、ステップＳ１４５に処理を進める。一方、２段目スタック３２を昇温する必要が無い場合には（ステップＳ１４４で不要）、ステップＳ１５５に処理を進める。 In step S144, the control unit 31 determines whether it is necessary to raise the temperature of the second stage stack 32. For example, if the temperature of the second-stage stack 32 is equal to or higher than a predetermined value, electric power to be the target output can be generated even if the difference value A is equal to or higher than the predetermined value. 31 determines that it is not necessary to heat the second stage stack 32. If it is necessary to raise the temperature of the second stage stack 32 (needed in step S144), the process proceeds to step S145. On the other hand, when it is not necessary to raise the temperature of the second stage stack 32 (not needed in step S144), the process proceeds to step S155.
　ステップＳ１４５において、制御部３１は、２段目スタック３２の出力が目標出力に到達したか否かを判断する。２段目スタック３２の出力が目標出力に到達した場合には（ステップＳ１４５でＹＥＳ）、ステップＳ１４９に処理を進める。一方、２段目スタック３２の出力が目標出力に到達しない場合には（ステップＳ１４５でＮＯ）、ステップＳ１４７に処理を進める。 In step S145, the control unit 31 determines whether the output of the second stack 32 has reached the target output. If the output of the second stage stack 32 has reached the target output (YES in step S145), the process proceeds to step S149. On the other hand, when the output of the second stage stack 32 does not reach the target output (NO in step S145), the process proceeds to step S147.
　ステップＳ１４７，Ｓ１４８において、制御部３１は、２段目スタック３２の目標セル電圧をメモリ等から読み込み、セル電圧を所定値に制御して、２段目スタック３２の作動温度の上昇に伴って増大する発電出力が目標出力に到達するように制御する。この処理は、前述した図４のステップＳ３３，Ｓ３４と同様の処理を実施する。この処理が終了した場合には、ステップＳ１５１に処理を進める。 In steps S147 and S148, the control unit 31 reads the target cell voltage of the second stage stack 32 from the memory or the like, controls the cell voltage to a predetermined value, and increases as the operating temperature of the second stage stack 32 increases. Control so that the generated output reaches the target output. This process carries out the same process as steps S33 and S34 in FIG. 4 described above. If this process ends, the process proceeds to step S151.
　一方、２段目スタック３２の出力が目標出力に到達した場合には（ステップＳ１４５でＹＥＳ）、ステップＳ１４９において、制御部３１は、２段目スタック３２の出力が目標出力を維持するように出力電流を制御し、ステップＳ１５０において、目標出力判定フラグをオンとする。 On the other hand, if the output of second-stage stack 32 has reached the target output (YES in step S145), control unit 31 causes output of second-stage stack 32 to maintain the target output in step S149. The current is controlled, and in step S150, the target output determination flag is turned on.
　つまり、ステップＳ１４５～Ｓ１５０の処理では、２段目スタック３２の出力が目標出力に到達していなければ、セル電圧制御を行うことにより２段目スタック３２を昇温させることができ、２段目スタック３２の出力が目標出力に到達している場合には、これ以上出力を上昇させる必要が無いため、セル電圧制御を行わずに目標出力に到達したことを示すフラグをオンとしている。 That is, in the processes of steps S145 to S150, if the output of the second stage stack 32 does not reach the target output, the second stage stack 32 can be heated by performing the cell voltage control, and the second stage When the output of the stack 32 has reached the target output, it is not necessary to further increase the output, so a flag indicating that the target output has been reached without performing cell voltage control is turned on.
　ステップＳ１５１において、制御部３１は、２段目スタック３２の温度が目標温度（２段目スタック３２の通常運転時の温度）に到達したか否かを判断する。２段目スタック３２の温度が目標温度に到達していない場合には（ステップＳ１５１でＮＯ）、ステップＳ１５２に処理を進める。一方、２段目スタック３２の温度が目標温度に到達している場合には（ステップＳ１５１でＹＥＳ）、ステップＳ１５３に処理を進める。 In step S151, the control unit 31 determines whether the temperature of the second stack 32 has reached the target temperature (the temperature at the time of normal operation of the second stack 32). If the temperature of the second stage stack 32 has not reached the target temperature (NO in step S151), the process proceeds to step S152. On the other hand, if the temperature of the second stack 32 has reached the target temperature (YES in step S151), the process proceeds to step S153.
　ステップＳ１５２において、制御部３１は、酸素過剰率制御［３］を実行する。酸素過剰率制御［３］の詳細については、図１４に示すフローチャートを参照して後述する。 In step S152, the control unit 31 executes excess oxygen ratio control [3]. The details of the excess oxygen ratio control [3] will be described later with reference to the flowchart shown in FIG.
　ステップＳ１５３において、制御部３１は、２段目スタック３２の温度が目標温度に到達したことを示す目標温度到達判定フラグをオンとする。その後、ステップＳ１５４に処理を進める。 In step S153, the control unit 31 turns on a target temperature attainment determination flag indicating that the temperature of the second stack 32 has reached the target temperature. Thereafter, the process proceeds to step S154.
　ステップＳ１５４において、制御部３１は、２段目スタック３２が目標温度及び目標出力に到達したか否かを判断する。２段目スタック３２が目標温度及び目標出力に到達した場合には（ステップＳ１５４でＹＥＳ）ステップＳ１５５に処理を進め、その後、本処理を終了する。一方、２段目スタック３２が目標温度及び目標出力に到達していない場合には（ステップＳ１５４でＮＯ）、本処理を終了する。 In step S154, the control unit 31 determines whether the second stage stack 32 has reached the target temperature and the target output. If the second stage stack 32 has reached the target temperature and the target output (YES in step S154), the process proceeds to step S155, and then the process ends. On the other hand, when the second stage stack 32 has not reached the target temperature and the target output (NO in step S154), the present process ends.
　次に、図１３のステップＳ１５２に示した酸素過剰率制御［３］の詳細な処理手順について、図１４に示すフローチャートを参照して説明する。初めに、図１４のステップＳ１６１において、制御部３１は、１段目スタック１１より出力されるガス中の酸素量を演算する。この演算は、１段目スタック１１に供給される酸素量と、発電に用いられる酸素量との関係から求めることができる。 Next, the detailed processing procedure of the excess oxygen ratio control [3] shown in step S152 of FIG. 13 will be described with reference to the flowchart shown in FIG. First, in step S161 of FIG. 14, the control unit 31 calculates the amount of oxygen in the gas output from the first-stage stack 11. This calculation can be obtained from the relationship between the amount of oxygen supplied to the first stage stack 11 and the amount of oxygen used for power generation.
　ステップＳ１６２において、制御部３１は、２段目スタック３２の目標最小酸素過剰率を読み込む。この処理では、例えば、制御部３１は、メモリ（図示省略）に記憶されている数値を読み込むことにより取得する。 In step S162, the control unit 31 reads the target minimum oxygen excess rate of the second stack 32. In this process, for example, the control unit 31 acquires the numerical value stored in a memory (not shown) by reading it.
　ステップＳ１６３において、制御部３１は、電流・電圧センサ５２により２段目スタック３２の出力電流を検出する。 In step S163, the control unit 31 detects the output current of the second stage stack 32 by the current / voltage sensor 52.
　ステップＳ１６４において、制御部３１は、２段目スタック３２の要求最小酸素量を演算する。この処理では、制御部３１は、ステップＳ１６３の処理で検出した出力電流に基づき、この電流を発生させるために必要な酸素量（最低限必要な酸素量）を求め、更に、この酸素量にステップＳ１６２の処理で取得した目標最小酸素過剰率を乗じることにより、最小酸素量を求める。この際、ステップＳ１６１の処理で読み込む酸素過剰率は、通常運転時の酸素過剰率よりも低い数値に設定されているので、最小酸素量は、通常運転時における最小酸素量よりも低い数値となる。 In step S164, the control unit 31 calculates the required minimum oxygen amount of the second stage stack 32. In this process, based on the output current detected in the process of step S163, the control unit 31 determines the amount of oxygen necessary to generate this current (minimum necessary amount of oxygen), and further, the step of this oxygen amount is performed. The minimum oxygen content is determined by multiplying the target minimum oxygen excess rate acquired in the process of S162. At this time, since the excess oxygen rate read in the process of step S161 is set to a value lower than the excess oxygen rate during normal operation, the minimum oxygen amount is lower than the minimum oxygen amount during normal operation. .
　ステップＳ１６５において、制御部３１は、ステップＳ１６４の処理で求めた最小酸素量と、ステップＳ１６１の処理で求めた１段目スタック１１より出力されるガス中の酸素量（２段目供給酸素量）とを比較する。２段目供給酸素量が最小酸素量よりも大きい場合には（ステップＳ１６５でＹＥＳ）、ステップＳ１６６に処理を進める。一方、２段目供給酸素量が最小酸素量よりも小さい場合には（ステップＳ１６５でＮＯ）、ステップＳ１６７に処理を進める。 In step S165, the control unit 31 determines the minimum amount of oxygen obtained in the process of step S164 and the amount of oxygen in the gas output from the first stack 11 obtained in the process of step S161 (the amount of oxygen supplied in the second stage). Compare with. If the second stage supply oxygen amount is larger than the minimum oxygen amount (YES in step S165), the process proceeds to step S166. On the other hand, if the second stage supply oxygen amount is smaller than the minimum oxygen amount (NO in step S165), the process proceeds to step S167.
　ステップＳ１６６において、制御部３１は、図９に示した冷却空気流量制御装置３４より２段目スタック３２に供給する冷却空気流量をゼロに設定する。つまり、１段目スタック１１より送出されるガス中に含まれる酸素量（２段目供給酸素量）よりも２段目スタック３２が要求する最小酸素量の方が小さい場合には、２段目スタック３２の発電に要する酸素が足りているので、空気ブロワ１２からの冷却空気を供給しない。 In step S166, the control unit 31 sets the flow rate of the cooling air supplied to the second stage stack 32 from the cooling air flow control device 34 shown in FIG. 9 to zero. That is, if the minimum amount of oxygen required by the second stage stack 32 is smaller than the amount of oxygen contained in the gas delivered from the first stage stack 11 (the second stage supply oxygen amount), the second stage Since the oxygen required for the power generation of the stack 32 is sufficient, the cooling air from the air blower 12 is not supplied.
　ステップＳ１６７において、制御部３１は、冷却空気流量制御装置３４より２段目スタック３２に供給する冷却空気流量を演算する。つまり、１段目スタック１１より送出されるガス中に含まれる酸素量（２段目供給酸素量）よりも２段目スタック３２が要求する最小酸素量の方が大きい場合には、２段目スタック３２の発電に要する酸素が足りないので、冷却空気流量制御装置３４より供給するべき冷却空気量を求める。 In step S167, the control unit 31 calculates the flow rate of cooling air supplied from the cooling air flow control device 34 to the second stage stack 32. That is, if the minimum amount of oxygen required by the second stage stack 32 is larger than the amount of oxygen contained in the gas delivered from the first stage stack 11 (the second stage supply oxygen amount), the second stage Since the oxygen required for the power generation of the stack 32 is insufficient, the amount of cooling air to be supplied is obtained from the cooling air flow control device 34.
　ステップＳ１６８において、制御部３１は、１段目スタック１１に供給される空気量と、冷却空気流量制御装置３４より送出される空気量の加算値を、１段目スタック１１と２段目スタック３２が要求する空気量の合算値として演算する。 In step S168, the control unit 31 adds the amount of air supplied to the first-stage stack 11 and the amount of air sent from the cooling air flow control device 34 to the first-stage stack 11 and the second-stage stack 32. Calculated as the total value of the air volume required by
　ステップＳ１６９において、制御部３１は、２段目スタック３２のカソード３２ａに供給する空気量を設定する。ステップＳ１７０において、制御部３１は、冷却空気流量制御装置３４の開度を調整して、カソード３２ａに供給する冷却空気量が所望する数値となるように制御する。こうして、２段目スタック３２のカソード３２ａに供給される酸素量が、必要最小限の酸素量に酸素過剰率を乗じた最小酸素量以下にならないように制御して、発電に必要な酸素量を供給することができ、かつ、２段目スタック３２の冷却効果を低減させることにより、２段目スタック３２の温度を即時に昇温させることができる。 In step S169, the control unit 31 sets the amount of air supplied to the cathode 32a of the second stage stack 32. In step S170, the control unit 31 adjusts the opening degree of the cooling air flow control device 34 so that the amount of cooling air supplied to the cathode 32a becomes a desired numerical value. Thus, the amount of oxygen supplied to the cathode 32a of the second-stage stack 32 is controlled so as not to be less than the minimum amount of oxygen obtained by multiplying the minimum necessary amount of oxygen by the oxygen excess rate. The temperature of the second stage stack 32 can be immediately raised by reducing the cooling effect of the second stage stack 32.
　このようにして、本実施形態に係る燃料電池システム１０１ａでは、互いに直列接続された１段目スタック１１及び２段目スタック３２を有する構成において、２段目スタック３２を起動する際に、燃焼バーナ２１より送出される燃焼ガス量の制御と、酸素過剰率の制御と、セル電圧を所定の範囲とする制御とのうちの少なくとも一つの制御を行うので、２段目スタック３２を迅速に目標出力に到達させることができ、２段目スタック３２による発電をいち早く開始することができる。 Thus, in the fuel cell system 101a according to the present embodiment, in the configuration having the first stack 11 and the second stack 32 connected in series with each other, the combustion burner is activated when the second stack 32 is started. At least one of the control of the amount of combustion gas delivered from 21, the control of the excess oxygen rate, and the control of setting the cell voltage within a predetermined range, the target output of the second stage stack 32 is quickly achieved. The second stage stack 32 can quickly start generating power.
　また、燃料電池システム１０１ａは、２段目スタック３２の温度が発電可能温度に到達していない場合には、システムに要求される目標出力が高いほど、燃焼バーナ２１（酸化剤加熱部）より出力する燃焼ガスの温度が高くなるように制御される。それゆえ、燃焼バーナ２１より出力される燃焼ガスが１段目スタック１１を経由して２段目スタック３２のカソード３２ａに流入するので、２段目スタック３２を迅速に昇温でき、目標温度に到達させるまでの時間をより一層短縮することができる。 In addition, when the temperature of the second stage stack 32 does not reach the power generation possible temperature, the fuel cell system 101a outputs more power from the combustion burner 21 (oxidant heater) as the target output required for the system is higher. The temperature of the combustion gas is controlled to be high. Therefore, since the combustion gas output from the combustion burner 21 flows into the cathode 32a of the second stack 32 via the first stack 11, the second stack 32 can be rapidly heated, and the target temperature is reached. The time to reach can be further shortened.
　更に、２段目スタック３２の温度が発電可能温度に到達している場合には、燃焼バーナ２１による加熱を停止して、２段目スタック３２に供給する酸素過剰率を低く設定する制御と、２段目スタック３２のセル電圧を所定の範囲内とする制御とのうちの少なくとも一つの制御を行うので、燃焼バーナ２１を燃焼させるために要する燃料量を削減でき、エネルギーの消費を低減することができる。 Furthermore, when the temperature of the second stage stack 32 has reached the power generation possible temperature, control to stop the heating by the combustion burner 21 and set the excess oxygen ratio supplied to the second stage stack 32 low; Since at least one control of controlling the cell voltage of the second stage stack 32 within a predetermined range is performed, the amount of fuel required to burn the combustion burner 21 can be reduced, and energy consumption can be reduced. Can.
　また、１段目スタック１１のカソード１１ａ出口と、２段目スタック３２のカソード３２ａ入口を接続する流路に、冷却空気導入通路３３を接続し、冷却空気導入通路３３を経由して、空気ブロワ１２より送出される空気の一部がカソード３２ａに導入されるので、２段目スタック３２のカソード３２ａで必要とされる最小酸素量を確実に確保することができる。 Further, the cooling air introduction passage 33 is connected to a flow path connecting the cathode 11 a outlet of the first stage stack 11 and the cathode 32 a inlet of the second stage stack 32, and an air blower is connected via the cooling air introduction passage 33. Since a part of the air delivered from 12 is introduced into the cathode 32a, the minimum amount of oxygen required in the cathode 32a of the second stage stack 32 can be assuredly ensured.
（第３実施形態）
　図１８は、本本実施形態に係る燃料電池システム１００が、外部負荷６１に接続される様子を示す説明図である。燃料電池システム１００及び外部電源６２により、中継装置６３を経由して外部負荷６１に電力が供給される。燃料電池システム１００は、外部負荷６１の要求電力に応じて、目標出力及び目標温度を設定する。燃料電池システム１００は、図１に示す構成を有している。 Third Embodiment
FIG. 18 is an explanatory view showing the fuel cell system 100 according to the present embodiment connected to the external load 61. As shown in FIG. Electric power is supplied to the external load 61 via the relay device 63 by the fuel cell system 100 and the external power supply 62. The fuel cell system 100 sets a target output and a target temperature in accordance with the required power of the external load 61. The fuel cell system 100 has the configuration shown in FIG.
　以下、本実施形態に係る燃料電池システム１００の作用について、図１９に示すフローチャートを参照して説明する。初めに、ステップＳ２０１において、燃料電池システム１００の制御部３１（図１参照）は、外部負荷６１の要求電力を検出する。 Hereinafter, the operation of the fuel cell system 100 according to the present embodiment will be described with reference to the flowchart shown in FIG. First, in step S201, the control unit 31 (see FIG. 1) of the fuel cell system 100 detects the required power of the external load 61.
　ステップＳ２０２において、制御部３１は、スタック１１の発電電力を求める。ステップＳ２０３において、制御部３１は、外部負荷要求電力とスタック１１の発電電力との差分値を演算する。 In step S202, the control unit 31 obtains the generated power of the stack 11. In step S203, the control unit 31 calculates a difference value between the external load required power and the generated power of the stack 11.
　ステップＳ２０４において、制御部３１は、ステップＳ２０３の処理で求められた差分値に基づいて、スタック１１の目標出力及び目標温度を設定する。 In step S204, the control unit 31 sets the target output and the target temperature of the stack 11 based on the difference value obtained in the process of step S203.
　外部負荷要求電力とスタック１１の発電電力との差分値に対応する電力は、外部電源６２より供給されている。外部電源６２により供給されている該電力を燃料電池システム１００で補うために、制御部３１は、差分値に応じた目標出力及び目標温度を設定する。 Power corresponding to the difference between the external load required power and the power generated by the stack 11 is supplied from the external power supply 62. In order to compensate the power supplied from the external power supply 62 by the fuel cell system 100, the control unit 31 sets a target output and a target temperature according to the difference value.
　このように、本実施形態に係る燃料電池システム１００は、外部電源６２により供給されている電力を、外部負荷要求電力とスタック１１の発電電力との差分値として演算し、該差分値に応じてスタック１１の目標出力を変動している。それゆえ、燃料電池システム１００は、外部負荷６１が必要とする電力に応じて、即時に発電量を変更して外部負荷６１に供給することができる。従って、スタック１１の昇温速度が必要に応じて制御されることになり、昇温制御に要するエネルギー量を低減することができる。なお、制御部３１は、外部負荷要求電力と外部電源６２の出力電力との差分値に応じて、スタック１１の目標出力または目標温度を設定してもよい。 As described above, the fuel cell system 100 according to the present embodiment calculates the power supplied by the external power supply 62 as a difference between the external load required power and the generated power of the stack 11, and The target output of the stack 11 is changed. Therefore, the fuel cell system 100 can change the amount of power generation immediately and supply it to the external load 61 according to the power required by the external load 61. Therefore, the temperature increase rate of the stack 11 is controlled as necessary, and the amount of energy required for the temperature increase control can be reduced. The control unit 31 may set the target output or the target temperature of the stack 11 in accordance with the difference value between the external load required power and the output power of the external power supply 62.
（第４実施形態）
　図２０は、本実施形態に係る燃料電池システム１００が、外部負荷６１に接続される様子を示す説明図である。燃料電池システム１００及び蓄電装置６４により、外部負荷６１に電力が供給される。燃料電池システム１００は、外部負荷６１の要求電力及び蓄電装置６４の蓄電量に応じて、目標出力及び目標温度を設定する。なお、燃料電池システム１００は、図１に示す構成を有している。 Fourth Embodiment
FIG. 20 is an explanatory view showing the fuel cell system 100 according to the present embodiment connected to the external load 61. As shown in FIG. Electric power is supplied to the external load 61 by the fuel cell system 100 and the power storage device 64. Fuel cell system 100 sets a target output and a target temperature according to the required power of external load 61 and the storage amount of power storage device 64. The fuel cell system 100 has the configuration shown in FIG.
　以下、本実施形態に係る燃料電池システムの作用について、図２１に示すフローチャートを参照して説明する。初めに、ステップＳ２１１において、燃料電池システム１００の制御部３１（図１参照）は、外部負荷６１の要求電力を検出する。 Hereinafter, the operation of the fuel cell system according to the present embodiment will be described with reference to the flowchart shown in FIG. First, in step S211, the control unit 31 (see FIG. 1) of the fuel cell system 100 detects the required power of the external load 61.
　ステップＳ２１２において、制御部３１は、蓄電装置６４の蓄電量割合（ＳＯＣ；State Of Charge）を検出する。ステップＳ２１３において、制御部３１は、燃料電池システム１００の目標出力及び目標温度を設定する。この処理は、図２２に示すマップを用いて設定することができる。図２２は、ＳＯＣと外部負荷要求電力との関係を示すマップである。制御部３１は、このマップに基づいてスタック１１の目標出力及び目標温度を設定する。 In step S212, control unit 31 detects the ratio (SOC: State Of Charge) of the storage amount of power storage device 64. In step S213, the controller 31 sets a target output and a target temperature of the fuel cell system 100. This process can be set using the map shown in FIG. FIG. 22 is a map showing the relationship between the SOC and the external load required power. The control unit 31 sets a target output and a target temperature of the stack 11 based on this map.
　このように、本実施形態に係る燃料電池システム１００は、蓄電装置６４の蓄電量割合（ＳＯＣ）に応じてスタック１１の目標出力を変動している。それゆえ、燃料電池システム１００は、外部負荷６１が必要とする電力に応じて、即時に発電量を変更して外部負荷６１に供給することができる。従って、スタック１１の昇温速度が、蓄電装置６４の蓄電量割合に応じて制御されることになり、昇温制御に要するエネルギー量を低減することができる。 As described above, in the fuel cell system 100 according to the present embodiment, the target output of the stack 11 fluctuates in accordance with the storage amount ratio (SOC) of the power storage device 64. Therefore, the fuel cell system 100 can change the amount of power generation immediately and supply it to the external load 61 according to the power required by the external load 61. Therefore, the temperature increase rate of the stack 11 is controlled in accordance with the ratio of the amount of stored power of the power storage device 64, and the amount of energy required for the temperature increase control can be reduced.
（第５実施形態）
　図２３は、本実施形態に係る燃料電池システム１００が、例えば、外部負荷６１（本実施形態では車両用モータとする）に接続される様子を示す説明図である。燃料電池システム１００及び蓄電装置６４により、外部負荷６１に電力が供給される。 Fifth Embodiment
FIG. 23 is an explanatory view showing how the fuel cell system 100 according to the present embodiment is connected to, for example, an external load 61 (in this embodiment, a vehicle motor). Electric power is supplied to the external load 61 by the fuel cell system 100 and the power storage device 64.
　燃料電池システム１００は、車両に搭載される制御装置から、車両の移動速度及び移動方向のデータを取得可能な構成とされている。燃料電池システム１００は、車両の移動方向と移動速度に基づき、所定時間後の要求出力を推定し、推定した要求出力と蓄電装置６４の蓄電量割合（ＳＯＣ）に基づいて、燃料電池システム１００の目標出力または目標温度を設定する。 The fuel cell system 100 is configured to be able to acquire data on the moving speed and moving direction of the vehicle from a control device mounted on the vehicle. Fuel cell system 100 estimates the required output after a predetermined time based on the moving direction and moving speed of the vehicle, and based on the estimated required output and the storage amount ratio (SOC) of power storage device 64, Set target output or target temperature.
　以下、本実施形態に係る燃料電池システム１００の作用について、図２４に示すフローチャートを参照して説明する。初めに、ステップＳ２３１において、燃料電池システム１００の制御部３１（図１参照）は、燃料電池システム１００が搭載される車両の位置情報（高度情報を含む）を取得する。この位置情報は、例えば、車両に搭載されるナビゲーションシステムのＧＰＳ情報より取得することができる。 Hereinafter, the operation of the fuel cell system 100 according to the present embodiment will be described with reference to the flowchart shown in FIG. First, in step S231, the control unit 31 (see FIG. 1) of the fuel cell system 100 acquires position information (including altitude information) of the vehicle on which the fuel cell system 100 is mounted. This position information can be acquired, for example, from GPS information of a navigation system mounted on a vehicle.
　ステップＳ２３２において、制御部３１は、車両の移動方向を演算する。ステップＳ２３３において、制御部３１は、車両の移動速度を検出する。 In step S232, control unit 31 calculates the moving direction of the vehicle. In step S233, the control unit 31 detects the moving speed of the vehicle.
　ステップＳ２３４において、制御部３１は、車両の移動速度及び移動方向に基づいて、所定時間後の要求出力を推定する。 In step S234, the control unit 31 estimates the required output after a predetermined time based on the moving speed and the moving direction of the vehicle.
　ステップＳ２３５において、制御部３１は、蓄電装置６４の蓄電割合（ＳＯＣ）を検出する。 In step S235, control unit 31 detects the storage ratio (SOC) of power storage device 64.
　ステップＳ２３６において、制御部３１は、ＳＯＣの値に基づいて、目標出力或いは目標温度を設定する。この際、目標出力或いは目標温度は、図２５に示すように、時系列的なデータとして設定される。また、この処理は、図２６に示すマップを用いて設定することができる。図２６はＳＯＣと推定出力との関係を示すマップである。制御部３１は、このマップに基づいてスタック１１の目標出力及び目標温度を設定する。 In step S236, the control unit 31 sets a target output or a target temperature based on the value of the SOC. At this time, the target output or target temperature is set as time series data as shown in FIG. Also, this process can be set using the map shown in FIG. FIG. 26 is a map showing the relationship between the SOC and the estimated output. The control unit 31 sets a target output and a target temperature of the stack 11 based on this map.
　これらの処理により、車両走行時における燃料電池システム１００の目標温度及び目標出力を、車両の走行状況に応じた時系列的なデータとして取得することができ、走行状況に応じた柔軟性の高い電力供給が可能となる。 By these processes, it is possible to acquire the target temperature and the target output of the fuel cell system 100 when the vehicle is traveling as time-series data according to the traveling condition of the vehicle, and power with high flexibility according to the traveling condition Supply becomes possible.
　このように、本実施形態に係る燃料電池システム１００では、スタック１１の昇温速度が、ＧＰＳ情報等により推定される所定時間後の目標出力或いは目標温度に応じて制御される。それゆえ、所定の出力が要求される時刻よりも早い時点で昇温制御を行うことができ、昇温制御に要するエネルギー消費量を低減することができる。 As described above, in the fuel cell system 100 according to the present embodiment, the temperature increase rate of the stack 11 is controlled according to the target output or the target temperature after a predetermined time estimated by the GPS information or the like. Therefore, the temperature rise control can be performed earlier than the time at which the predetermined output is required, and the energy consumption required for the temperature rise control can be reduced.
　本発明に係る燃料電池システムでは、燃料電池の温度が発電可能温度に到達した後、通常運転時の目標出力、または目標温度となるまで、酸化剤加熱部より出力される酸化剤の酸素過剰率を、燃料電池の目標出力での酸素過剰率よりも低く設定する制御と、燃料電池の出力電圧を所定の範囲内とする制御と、酸化剤加熱部による加熱制御とのうちの少なくとも一つの制御を行うので、燃料電池の出力を迅速に目標出力に到達させることができる。また、本発明に係る燃料電池システムは、スタック温度をいち早く目標運転時の温度まで昇温することができる。 In the fuel cell system according to the present invention, after the temperature of the fuel cell reaches the power generation possible temperature, the oxygen excess rate of the oxidant output from the oxidant heating unit until the target output in normal operation or the target temperature is reached. Is controlled to be lower than the excess oxygen ratio at the target output of the fuel cell, at least one of the control to make the output voltage of the fuel cell within a predetermined range, and the heating control by the oxidant heating unit Therefore, the output of the fuel cell can be quickly reached to the target output. Further, the fuel cell system according to the present invention can rapidly raise the stack temperature to the target operation temperature.
　以上、本発明の燃料電池システムを第１乃至５実施形態に基づいて説明したが、本発明はこれに限定されるものではなく、各部の構成は、同様の機能を有する任意の構成のものに置き換えることができる。 The fuel cell system of the present invention has been described above based on the first to fifth embodiments, but the present invention is not limited to this, and the configuration of each part may be any configuration having the same function. It can be replaced.
　例えば、各実施形態では、車載用に燃料電池システムを例に挙げて説明したが、本発明は車載用に限定されるものではない。本発明の燃料電池システムは、一般家庭用に用いられる燃料電池等の他の用途として用いることも可能である。 For example, in each embodiment, although a fuel cell system was mentioned as an example and explained to vehicles, this invention is not limited to vehicles. The fuel cell system of the present invention can also be used as another application such as a fuel cell used for general household use.
本出願は、２０１２年２月３日に出願された日本国特許願第２０１２－０２１５７６号に基づく優先権を主張しており、これらの出願の全内容がここに援用される。 This application claims priority based on Japanese Patent Application No. 2012-021576 filed on Feb. 3, 2012, the entire contents of which are incorporated herein by reference.
　１１　スタック、１段目スタック（燃料電池スタック）
　１１ａ　カソード
　１１ｂ　アノード
　１２　空気ブロワ
　１３　熱交換器
　１４　第１燃料ポンプ
　１５　熱交換型プレ改質装置
　１６　プレ改質器
　１７　燃焼器
　１９，２０　流量制御装置
　２１　燃焼バーナ
　２２　第２燃料ポンプ
　２３　アノードオフガス循環器
　２５　蒸発器
　３１　制御部
　３２　２段目スタック
　３２ａ　カソード
　３２ｂ　アノード
　３３　冷却空気導入通路
　３４　冷却空気流量制御装置
　４１ａ　入口温度センサ
　４１ｂ　出口温度センサ
　４２　電流・電圧センサ
　５１ａ　入口温度センサ
　５１ｂ　出口温度センサ
　５２　電流・電圧センサ
　６１　外部負荷
　６２　外部電源
　６３　中継装置
　６４　蓄電装置
　１００，１００ａ　燃料電池システム 11 Stack, 1st stack (fuel cell stack)
11 a cathode 11 b anode 12 air blower 13 heat exchanger 14 first fuel pump 15 heat exchange type pre-reformer 16 pre-reformer 17 combustor 19 and 20 flow controller 21 combustion burner 22 second fuel pump 23 anode off gas circulation 25 evaporator 31 control unit 32 second stage stack 32a cathode 32b anode 33 cooling air introduction passage 34 cooling air flow control device 41a inlet temperature sensor 41b outlet temperature sensor 42 current / voltage sensor 51a inlet temperature sensor 51b outlet temperature sensor 52 current · Voltage sensor 61 External load 62 External power supply 63 Relay device 64 Power storage device 100, 100a Fuel cell system

Claims (12)

  1. 　アノードに改質ガスが供給され、カソードに酸化剤が供給されて発電する燃料電池と、
    　前記カソードの上流側に設けられ、前記カソードに酸化剤を供給する酸化剤供給部と、
    　前記酸化剤供給部と前記カソードとの間に設けられ、前記酸化剤供給部より出力される酸化剤を加熱する酸化剤加熱部と、
    　前記燃料電池の起動時に、前記酸化剤加熱部で加熱された酸化剤を前記カソードに供給して前記燃料電池を昇温する制御を行い、かつ、前記燃料電池が発電可能温度に到達した後に、前記燃料電池が所定の目標出力或いは目標温度に到達するまで、下記（ａ），（ｂ），（ｃ）：
    　　（ａ）前記酸化剤加熱部より出力される酸化剤の酸素過剰率を、前記燃料電池の目標出力での酸素過剰率よりも低く設定する制御；
    　　（ｂ）前記燃料電池の出力電圧を所定の範囲内とする制御；
    　　（ｃ）前記酸化剤加熱部による加熱制御、
    のうちの少なくとも一つの制御を行う制御部と、
    　を備えたことを特徴とする燃料電池システム。     A fuel cell in which a reformed gas is supplied to the anode and an oxidant is supplied to the cathode to generate electricity;
    An oxidant supply unit disposed upstream of the cathode and supplying an oxidant to the cathode;
    An oxidant heating unit which is provided between the oxidant supply unit and the cathode and which heats the oxidant output from the oxidant supply unit;
    At startup of the fuel cell, the oxidant heated by the oxidant heating unit is supplied to the cathode to perform control to raise the temperature of the fuel cell, and after the fuel cell reaches the power generation possible temperature, The following (a), (b), (c): until the fuel cell reaches a predetermined target output or target temperature:
    (A) Control to set the oxygen excess rate of the oxidant output from the oxidant heating unit lower than the oxygen excess rate at the target output of the fuel cell;
    (B) controlling the output voltage of the fuel cell within a predetermined range;
    (C) heating control by the oxidizing agent heating unit,
    A control unit that performs at least one control of
    A fuel cell system comprising:
  2. 　前記制御部は、システムに要求される前記目標出力が予め設定した所定値よりも小さい場合には、前記（ｃ）の制御を行わず、前記（ａ），（ｂ）の少なくとも一つの制御により前記燃料電池を昇温することを特徴とする請求項１に記載の燃料電池システム。 The control unit does not perform the control of (c) when the target output required of the system is smaller than a predetermined value set in advance, and is controlled by at least one of (a) and (b). The fuel cell system according to claim 1, wherein the temperature of the fuel cell is raised.
  3. 　前記（ｂ）の制御において、前記燃料電池の出力電圧は、燃料電池出力がピークとなる電圧値に対して、一定の範囲内とすることを特徴とする請求項１または請求項２のいずれかに記載の燃料電池システム。 3. The control according to (b), wherein an output voltage of the fuel cell is in a predetermined range with respect to a voltage value at which a fuel cell output reaches a peak. The fuel cell system according to claim 1.
  4. 　前記燃料電池は、第１燃料電池、及び前記第１燃料電池の下流側に直列配置される第２燃料電池を含み、
    　前記制御部は、前記第１燃料電池が前記燃料電池システムに要求される目標出力に応じた運転条件で運転されている際に、前記第２燃料電池を起動する場合に、前記第２燃料電池が所定の目標出力或いは目標温度に到達するまで、前記燃料電池システムに要求される目標出力及び前記第２燃料電池の温度に応じて、下記の（ｄ），（ｅ），（ｆ）：
    　　（ｄ）前記第２燃料電池のカソードに供給する酸化剤の酸素過剰率を前記第２燃料電池の目標出力での酸素過剰率よりも低く設定する制御；
    　　（ｅ）第２燃料電池の出力電圧を所定の範囲内とする制御；
    　　（ｆ）前記酸化剤加熱部よる加熱制御、
    のうちの少なくとも一つの制御を行うことを特徴とする請求項１に記載の燃料電池システム。     The fuel cell includes a first fuel cell, and a second fuel cell disposed in series downstream of the first fuel cell.
    The control unit is configured to start the second fuel cell when the first fuel cell is operated under an operating condition according to a target output required of the fuel cell system. Depending on the target output required for the fuel cell system and the temperature of the second fuel cell until the target output or target temperature is reached, the following (d), (e), (f):
    (D) Control to set the oxygen excess rate of the oxidant supplied to the cathode of the second fuel cell lower than the oxygen excess rate at the target output of the second fuel cell;
    (E) Control for setting the output voltage of the second fuel cell within a predetermined range;
    (F) heating control by the oxidizing agent heating unit,
    The fuel cell system according to claim 1, wherein at least one control of the fuel cell system is performed.
  5. 　前記制御部は、前記第２燃料電池が発電可能温度に到達していない場合には、前記燃料電池システムに要求される目標出力が高いほど、前記酸化剤加熱部より出力する酸化剤温度を高くするように制御することを特徴とする請求項４に記載の燃料電池システム。 When the second fuel cell does not reach the power generation possible temperature, the control unit increases the oxidant temperature output from the oxidant heating unit as the target output required for the fuel cell system is higher. The fuel cell system according to claim 4, wherein the fuel cell system is controlled to
  6. 　前記制御部は、前記第２燃料電池が発電可能温度に到達した後、前記第２燃料電池に要求される目標出力または目標温度が現在の出力または温度よりも高い場合に、前記（ｄ），（ｅ）のうちの少なくとも一つの制御を行い、前記酸化剤加熱部による加熱制御を停止することを特徴とする請求項４に記載の燃料電池システム。 When the target output or the target temperature required for the second fuel cell is higher than the current output or the temperature after the second fuel cell reaches the power generation possible temperature, the control unit performs the operation (d), 5. The fuel cell system according to claim 4, wherein at least one of (e) is controlled to stop the heating control by the oxidant heating unit.
  7. 　前記第１燃料電池のカソード出口と、前記第２燃料電池のカソード入口との間の流路に、前記酸化剤供給部より送出される酸化剤の一部を導入するバイパス流路を設け、
    　前記第２燃料電池が必要とする酸化剤が不足する場合には、前記バイパス流路から前記第２燃料電池のカソードに酸化剤を導入することを特徴とする請求項４～請求項６のいずれか１項に記載の燃料電池システム。     The flow path between the cathode outlet of the first fuel cell and the cathode inlet of the second fuel cell is provided with a bypass flow path for introducing a part of the oxidizing agent delivered from the oxidizing agent supply unit,
    The oxidant according to any one of claims 4 to 6, wherein when the oxidant required by the second fuel cell is insufficient, the oxidant is introduced from the bypass flow channel to the cathode of the second fuel cell. The fuel cell system according to claim 1.
  8. 　前記（ｅ）の制御において、前記第２燃料電池の出力電圧は、前記第２燃料電池出力がピークとなる電圧値に対して、一定の範囲内とすることを特徴とする請求項４～請求項７のいずれか１項に記載の燃料電池システム。 The control method according to (e), wherein an output voltage of the second fuel cell is within a predetermined range with respect to a voltage value at which the output of the second fuel cell reaches a peak. Item 8. A fuel cell system according to any one of Items 7 to 7.
  9. 　前記制御部は、前記燃料電池に要求する目標出力または目標温度を、前記燃料電池が接続される外部負荷の要求電力と、前記外部負荷に別系統で電力を供給する外部電源の出力電力と、の差分に応じて設定することを特徴とする請求項１～請求項８のいずれか１項に記載の燃料電池システム。 The control unit generates a target output or target temperature required for the fuel cell, a required power of an external load to which the fuel cell is connected, and an output power of an external power supply for supplying power to the external load in a separate system. The fuel cell system according to any one of claims 1 to 8, wherein the fuel cell system is set according to the difference between
  10. 　前記制御部は、前記燃料電池に要求する目標出力または目標温度を、前記燃料電池が接続される外部負荷の要求電力と、前記外部負荷に別系統で電力を供給する蓄電池の残留蓄電量と、の差分に応じて設定することを特徴とする請求項１～請求項８のいずれか１項に記載の燃料電池システム。 The control unit determines a target output or target temperature required for the fuel cell, a required power of an external load connected to the fuel cell, and a residual storage amount of a storage battery for supplying power to the external load in another system. The fuel cell system according to any one of claims 1 to 8, wherein the fuel cell system is set according to the difference between
  11. 　前記燃料電池は、移動体に搭載されており、前記制御部は、前記燃料電池に要求される目標出力または目標温度を、前記移動体の位置情報及び速度情報に基づいて推定することを特徴とする請求項１～請求項８のいずれか１項に記載の燃料電池システム。 The fuel cell is mounted on a mobile body, and the control unit estimates a target output or target temperature required for the fuel cell based on position information and speed information of the mobile body. The fuel cell system according to any one of claims 1 to 8.
  12. 　燃料電池のカソードの上流側に設けられ、前記カソードに酸化剤を供給する酸化剤供給部と、前記酸化剤供給部と前記カソードとの間に設けられ、前記酸化剤供給部より出力される酸化剤を加熱する酸化剤加熱部と、を備える燃料電池システムにおいて、
    　前記燃料電池の起動時に、前記酸化剤加熱部で加熱された酸化剤を前記カソードに供給して前記燃料電池を昇温する制御を行うステップと、
    　前記燃料電池が発電可能温度に到達した後に、前記燃料電池が所定の目標出力或いは目標温度に到達するまで、下記（ａ），（ｂ），（ｃ）：
    　　（ａ）前記酸化剤加熱部より出力される酸化剤の酸素過剰率を、前記燃料電池の目標出力での酸素過剰率よりも低く設定する制御；
    　　（ｂ）前記燃料電池の出力電圧を所定の範囲内とする制御、
    　　（ｃ）前記酸化剤加熱部による加熱制御；
    のうちの少なくとも一つの制御を行うステップ、
    　を備えたことを特徴とする前記燃料電池システムの制御方法。     An oxidant supply unit provided upstream of a cathode of a fuel cell and supplying an oxidant to the cathode, and an oxidation agent provided between the oxidant supply unit and the cathode and output from the oxidant supply unit A fuel cell system comprising: an oxidant heating unit that heats
    Performing control of supplying the oxidizing agent heated by the oxidizing agent heating unit to the cathode and raising the temperature of the fuel cell when starting the fuel cell;
    After the fuel cell reaches the power generation possible temperature, the following (a), (b) and (c): until the fuel cell reaches a predetermined target output or target temperature:
    (A) Control to set the oxygen excess rate of the oxidant output from the oxidant heating unit lower than the oxygen excess rate at the target output of the fuel cell;
    (B) controlling the output voltage of the fuel cell within a predetermined range;
    (C) heating control by the oxidizing agent heating unit;
    Performing at least one control of
    And a control method of the fuel cell system.
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