WO2008142564A1 - Dispositif de commande et procédé de commande pour système de pile à combustible - Google Patents

Dispositif de commande et procédé de commande pour système de pile à combustible Download PDF

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Publication number
WO2008142564A1
WO2008142564A1 PCT/IB2008/001657 IB2008001657W WO2008142564A1 WO 2008142564 A1 WO2008142564 A1 WO 2008142564A1 IB 2008001657 W IB2008001657 W IB 2008001657W WO 2008142564 A1 WO2008142564 A1 WO 2008142564A1
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WIPO (PCT)
Prior art keywords
fuel cell
cell stack
gas
fuel
pressure
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Application number
PCT/IB2008/001657
Other languages
English (en)
Inventor
Syo Usami
Original Assignee
Toyota Jidosha Kabushiki Kaisha
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Publication of WO2008142564A1 publication Critical patent/WO2008142564A1/fr

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Classifications

    • 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
    • H01M8/04276—Arrangements for managing the electrolyte stream, e.g. heat exchange
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
    • H01M8/04126—Humidifying
    • 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
    • H01M8/04291—Arrangements for managing water in solid electrolyte fuel cell systems
    • 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
    • H01M8/04358—Temperature; Ambient temperature of the coolant
    • 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
    • H01M8/04365—Temperature; Ambient temperature of other components of a fuel cell or fuel cell stacks
    • 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
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04388—Pressure; Ambient pressure; Flow of anode 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
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04402—Pressure; Ambient pressure; Flow of anode exhausts
    • 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
    • H01M8/04492—Humidity; Ambient humidity; Water content
    • H01M8/04529—Humidity; Ambient humidity; Water content of the electrolyte
    • 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
    • H01M8/04731—Temperature of other components of a fuel cell or fuel cell stacks
    • 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
    • H01M8/04746—Pressure; Flow
    • H01M8/04753—Pressure; Flow of fuel cell reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—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
    • H01M8/04746—Pressure; Flow
    • H01M8/04761—Pressure; Flow of fuel cell exhausts
    • 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
    • H01M8/04828—Humidity; Water content
    • H01M8/0485—Humidity; Water content of the electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • 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

Definitions

  • the present invention relates to a control device and a control method for a fuel cell system and, more particularly, relates to a technique for detecting dry-up of electrolyte membranes in a fuel cell stack.
  • Each cell of a fuel cell is formed by sandwiching an electrolyte membrane between gas diffusion electrodes (a fuel gas electrode (anode) and an oxidant gas electrode (cathode)) and further sandwiching the assembly between separators each having a gas supply passage.
  • a fuel cell is formed by fixedly sandwiching a fuel cell stack in which a plurality of such cells are stacked and other members between end plates.
  • Each cell generates electricity by causing fuel gas supplied through the gas supply passage of the separator coupled to the anode thereof and oxidant gas supplied through the gas supply passage of the separator coupled to the cathode thereof to react with each other via the electrolyte membrane. More specifically, hydrogen contained in the fuel gas supplied to the anode is separated into protons (hydrogen ions) and electrons by an oxidation reaction at the catalyst layer forming the anode, and the protons move to the cathode through the electrolyte membrane and the electrons move to the cathode through an external circuit, whereby an electric current is generated. To maintain the power generation efficiency of each cell, it is necessary to keep the electrolyte membranes moist to ensure the transfer of protons.
  • a fuel cell stack composed of such cells includes a structure in which the water generated by the chemical reaction at the catalyst layers of the cathodes of the cells can be utilized, a configuration in which oxidant gas humidified by an external humidification module is supplied to the cells, a configuration in which coolant is supplied to the cells to cool the heat generated in the power generation process and so on to keep the electrolyte membranes of the cells moist.
  • JP-A- 2001-148253 describes a method for preventing a phenomenon in which excessive water in the vicinity of electrolyte membranes inhibits gas diffusion and the cell performance is deteriorated (flooding). In this method, the pressure loss of fuel gas is measured. Then, when it is determined that flooding is occurring, a control function is performed to increase the operating temperature or decrease the amount of humidification to the gas in order to overcome the flooding.
  • the humidity sensor needs to be provided with heat-retention means or anti- condensation means depending on the state of the gas as a target of detection. Since such means interferes with the detection of humidity of the gas, it takes a long time until a decrease in humidity of the gas is detected by the sensor and the detection of dryness of the electrolyte membranes is delayed. [0014] In the case of the method of detecting dryness of electrolyte membranes based on the resistance value of the fuel cell stack or the rate of decrease in voltage, the means for detecting the values may complicate the fuel cell system.
  • the present invention provides a control device and control method for a fuel cell system which has a simple configuration and can determine dryness of electrolyte membranes of a fuel cell properly.
  • a control device for a fuel cell system includes: measurement means for measuring a pressure loss of fuel gas in a fuel cell stack; and determination means for determining that an electrolyte membrane in the fuel cell stack is dry when a decrease is detected in the pressure loss measured by the measurement means.
  • the pressure loss of fuel gas is detected to determine dryness of the electrolyte membranes.
  • the control device for a fuel cell system may further include temperature measurement means for measuring an operating temperature of the fuel cell stack, and the determination means may determine that the electrolyte membrane is dry when the measured operating temperature is higher than a predetermined temperature and a decrease in the pressure loss of fuel gas is detected.
  • the temperature measurement means may measure a temperature of coolant discharged from the fuel cell stack as the operating temperature.
  • the control device for a fuel cell system may further include a pressure regulating valve, disposed in a path for the fuel gas discharged from the fuel cell stack, that adjusts a pressure of the fuel gas to maintain a flow rate of fuel gas to be supplied to the fuel cell stack generally constant.
  • the pressure loss of fuel gas is used to determine dryness of the electrolyte membranes. Since the pressure loss of fuel gas varies according to the amount of water contained in the porous passages, dryness of electrolyte membranes in a fuel cell stack having such porous gas passages can be determined more reliably according to the present invention.
  • the control device for a fuel cell system may further include control means that performs a control function to decrease the operating temperature of the fuel cell stack when the determination means determines that the electrolyte membrane is dry.
  • the present invention provides a control device for a fuel cell system which has a simple configuration and can determine dryness of electrolyte membranes of a fuel cell properly.
  • a control method for a fuel cell system includes, a first step of measuring a pressure loss of fuel gas in a fuel cell stack; a second step of determining whether the pressure loss is decreasing; and a third step of determining that an electrolyte membrane in the fuel cell stack is dry when it is determined that the pressure loss is decreasing.
  • a control device for a fuel cell system includes, includes: a pressure sensor that detects a pressure in a fuel gas passage; and a hydration state determining device that determines whether a pressure loss of fuel gas in a fuel cell stack is decreasing based on the detected pressure and determines that the electrolyte membrane is dry if it is determined that the pressure loss of fuel gas is decreasing.
  • a control method for a fuel cell system includes, the steps of detecting a pressure in a fuel gas passage; and determining whether a pressure loss of fuel gas in the fuel cell stack is decreasing based on the detected pressure; wherein it is determined that an electrolyte membrane in the fuel cell stack is dry if it is determined that the fuel-gas pressure is increasing.
  • FIG. 1 is a view illustrating an example configuration of a fuel cell system as one embodiment of the present invention.
  • FIG. 2 is a graph showing the characteristics of cells in a fuel cell stack 10.
  • FIG. 3A is a view schematically illustrating the water-containing state of a porous passage at the time indicated by a line (1) in the graph of FIG. 2.
  • FIG. 3B is a view schematically illustrating the water-containing state of a porous passage at the time indicated by a line (2) in the graph of FIG. 2.
  • FIG. 3C is a view schematically illustrating the water-containing state of a porous passage at the time indicated by a line (3) in the graph of FIG. 2.
  • FIG. 4 is a flowchart of an example of operation involved in humidity control in the fuel cell system of this embodiment.
  • FIG. 1 is a view illustrating an example configuration of a fuel cell system as one embodiment of the present invention.
  • the fuel cell system of this embodiment has a fuel cell stack 10; an air compressor 11; a humidification module 12; pressure regulating valves 15 and 24; a fuel gas supply device 21; a flow rate regulating valve 22; a gas-liquid separator 26; a fuel gas circulation pump 28; a cooler 29; pressure sensors 31 and 33; a temperature sensor 35; an ECU (Electric Control Unit) 20, and so on.
  • ECU Electronic Control Unit
  • the air compressor 11 compresses air introduced thereinto from the atmosphere through an air filter or the like as oxidant gas and delivers the compressed air into a pipe 41.
  • the oxidant gas to be supplied to a fuel cell stack is not limited to such compressed air (oxidant gas delivered from the air compressor 11).
  • the oxidant gas delivered into the pipe 41 is humidified in the humidification module 12, and is supplied to the fuel cell stack 10 through an oxidant gas supply pipe 43.
  • the fuel gas supply device 21 supplies hydrogen gas or hydrogen mixed gas, for example, as fuel gas.
  • the fuel gas supplied from the fuel gas supply device 21, the flow rate of which is controlled by the flow rate regulating valve 22, is fed into a pipe 51.
  • the flow rate regulating valve 22 delivers the fuel gas supplied from the fuel gas supply device 21 in an amount corresponding to the amount of electricity that the fuel cell stack 10 is required to generate, for example.
  • the fuel gas having passed through the flow rate regulating valve 22 is supplied to the fuel cell stack 10 through the fuel gas supply pipe 51 connected to the fuel gas inlet of the fuel cell stack 10.
  • the fuel cell stack 10 is formed by stacking a plurality of cells. Each cell is formed by sandwiching an electrolyte membrane between gas diffusion electrodes (a fuel gas electrode (anode) and an oxidant gas electrode (cathode)), and sandwiching the assembly between separators each having a gas supply passage. In each cell in the fuel cell stack 10, the fuel gas and the oxidant gas supplied thereto as described above are caused to react with each other via the electrolyte membrane to generate electricity.
  • gas diffusion electrodes a fuel gas electrode (anode) and an oxidant gas electrode (cathode)
  • anode off gas The fuel gas which is not consumed for the generation of electricity
  • cathode off gas The oxidant gas which is not consumed for the generation of electricity
  • the pressure regulating valve 15 is disposed between a pipe 44 connected to the cathode off gas outlet of the fuel cell stack 10 and a pipe 46 connected to the humidification module 12, and adjusts the pressures of the oxidant gas and the cathode off gas in the pipes 44 and 43 and the fuel cell stack 10.
  • the cathode off gas having passed through the pressure regulating valve 15 is fed into the pipe 46.
  • the humidification module 12 takes in the oxidant gas supplied from the air compressor 11 through the pipe 41 and the cathode off gas having passed through the pressure regulating valve 15 through the pipe 46 and mixes the gases.
  • the mixed gas is humidified by the water contained in the cathode off gas and is supplied to the fuel cell stack 10.
  • a portion of the cathode off gas having passed through the pressure regulating valve 15 is fed into an exhaust passage (not shown) through a pipe 48.
  • the oxidant gas delivered from the air compressor 11 is humidified in the humidification module 12 and then supplied to the cathode of each cell in the fuel cell stack 10. With this configuration, the electrolyte membranes of the cells are kept moist.
  • the pressure regulating valve 24 is disposed between a pipe 52 connected to the anode off gas outlet of the fuel cell stack 10 and a pipe 53 connected to the gas- liquid separator 26. As described later, in the fuel cell system of this embodiment, the pressure loss of the fuel gas which occurs when the fuel gas passes through the cells in the fuel cell stack 10 is detected.
  • the pressure regulating valve 24 maintains the pressure of anode off gas at the anode off gas outlet of the fuel cell stack 10 constant so that the pressure loss of the fuel gas can be detected accurately. This is because when the pressure of the anode off gas varies, the flow rate of the fuel gas being supplied to the fuel cell stack 10 is varied to cause variation in the pressure loss of the fuel gas.
  • the anode off gas having passed through the pressure regulating valve 24 is fed into the pipe 53.
  • the gas-liquid separator 26 removes the liquid component from the anode off gas having passed through the pressure regulating valve 24 and flowing through the pipe 53.
  • the gas-liquid separator 26 separates gas and liquid by condensing the water vapor contained in the anode off gas introduced into it on the interior wall surfaces thereof, for example.
  • the anode off gas, from which the liquid component has been removed, is delivered toward the fuel gas circulation pump 28 through a pipe 55.
  • the fuel gas circulation pump 28 has a rotary driving motor or the like and delivers the anode off gas flowing through the pipe 55 into a pipe 57 to resupply the anode off gas to the fuel cell stack 10.
  • the anode off gas flowing through the pipe 57 is mixed with the fuel gas supplied from the fuel gas supply device 21 in the pipe 51 and is resupplied to the fuel cell stack 10.
  • an anode off gas circulation pathway through which the anode off gas which is not used for generation of electricity and discharged from the fuel cell stack 10 is supplied again to the fuel cell stack 10 is formed in the fuel cell system of this embodiment.
  • the present invention is not limited to a fuel cell system having an anode off gas circulation pathway, and the fuel cell system may not have such an anode off gas circulation pathway.
  • the pressure sensor 31 is disposed in the vicinity of the fuel gas inlet of the fuel cell stack 10 in the pipe 51, and the pressure sensor 33 is disposed in the vicinity of the anode off gas outlet of the fuel cell stack 10 in the pipe 52.
  • the pressure sensor 31 detects the pressure of the fuel gas being supplied to the fuel cell stack 10
  • the pressure sensor 33 detects the pressure of the anode off gas discharged from the fuel cell stack 10. The pressure of the fuel gas and the pressure of the anode off gas detected by the pressure sensors 31 and 33, respectively, are transmitted to the ECU 20.
  • the installation positions and the detection principles of the pressure sensors 31 and 33 are not specifically limited as long as the difference between the pressure of the fuel gas before being supplied to the cells in the fuel cell stack 10 and the pressure of the anode off gas having passed through the cells can be measured. Therefore, the pressure sensors 31 and 33 may be disposed in a supply passage through which the fuel gas is supplied to the cells in the fuel cell stack 10 and a discharge passage through which the anode off gas having passed through the cells flows, respectively. Alternatively, one differential pressure sensor may be used to measure the difference between the pressures (pressure loss).
  • coolant (cooling water) is supplied to the fuel cell stack 10 to cause the fuel cell to operate at an optimum temperature.
  • the coolant removes heat from the cells while flowing through cooling plates interposed between the cells, for example, and is eventually discharged from a coolant outlet.
  • the coolant discharged from the coolant outlet is delivered to the cooler 29 through a pipe 61 connected to the coolant outlet.
  • the cooler 29 takes in the coolant heated by absorbing heat from the cells in the fuel cell stack 10 through the pipe 61 and cools the coolant.
  • the cooler 29 cools the coolant introduced through the pipe 61 with air supplied by a cooling fan provided therein and delivers the cooled coolant into a pipe 62.
  • the coolant delivered into the pipe 62 is supplied to the fuel cell stack 10.
  • the fuel cell system of this embodiment has a coolant circulation system in which the coolant heated by absorbing heat from the cells in the fuel cell stack 10 is cooled in the cooler 29 and supplied again to the fuel cell stack 10.
  • the temperature sensor 35 is disposed in the vicinity of the coolant outlet of the fuel cell stack 10 in the pipe 61 to measure the temperature of the coolant discharged from the fuel cell stack 10.
  • the temperature sensor 35 detects the temperature of the coolant heated by absorbing heat from the cells in the fuel cell stack 10 and discharged from the fuel cell stack 10. The detected coolant temperature is transmitted to the ECU 20.
  • the installation position and the temperature detection principle of the temperature sensor 35 is not specifically limited as long as the temperature of the coolant reflecting the heat generated by the cells in the fuel cell stack 10 can be measured.
  • the temperature sensor 35 may be located in a discharge passage through which the coolant having passed through the cells in the fuel cell stack 10 flows. Furthermore, the temperature in the fuel cell stack 10 or the temperature at a specific point on the fuel cell stack 10 itself may be measured instead of the coolant temperature if the operating temperature of the fuel cell stack 10 can be measured.
  • the ECU 20 is constituted of a CPU (Central Processing Unit); a memory; an input-output interface and so on.
  • the CPU executes a control program stored in the memory to control the humidity in the fuel cell stack 10.
  • the ECU 20 can be regarded as the control device of the present invention.
  • the ECU 20 determines dryness of the electrolyte membranes of the cells based on the pressure of the fuel gas and the pressure of the anode off gas detected by the pressure sensors 31 and 33, respectively, and the coolant temperature detected by the temperature sensor 35. The method by which the ECU 20 determines dryness of the electrolyte membranes is described later.
  • the ECU 20 performs a specific humidity control function based on the dryness of the electrolyte membranes of the cells determined. That is, the ECU 20 performs a specific humidity control function to increase the moistness of the electrolyte membranes as the electrolyte membranes are drier to keep the electrolyte membranes in a suitably moist condition.
  • the ECU 20 performs a control function to decrease the operating temperature of the fuel cell stack 10, for example, as the humidity control.
  • the ECU 20 may accomplish the humidity control by causing the humidification module 12 to control the amount of humidification, by controlling the feed rate of the oxidant gas, or by controlling the feed rate of the coolant.
  • the way of controlling the humidity by the ECU 20 is not specifically limited.
  • FIG. 2 is a graph showing the characteristics of cells in the fuel cell stack 10.
  • current density, cell voltage, cell resistance and coolant temperature as characteristic values, air pressure loss as the pressure loss of the oxidant gas, and hydrogen pressure loss as the pressure loss of the fuel gas are shown in connection with the passage of the operating time.
  • FIG. 2 at the time when 1500 seconds have passed indicated by a line (1), a state in which the cell resistance is low and the cell voltage is high is shown. This indicates that the electrolyte membranes of the cells are kept sufficiently moist to ensure proper transfer of protons.
  • a state in which the cell resistance increases extremely and the cell voltage decreases extremely, while the coolant temperature is high is shown. This is a state in which the electrolyte membranes of the cells are too dry to ensure proper transfer of protons.
  • this point of time is detected as indicating a time when the electrolyte membranes of the cells become dry and the humidity control function as described before is performed on or before the electrolyte membranes start drying.
  • the hydrogen pressure loss starts decreasing when the electrolyte membranes start drying around the point of time indicated by the line (2).
  • detecting the point of time when the hydrogen pressure loss starts decreasing as indicating a time when the electrolyte membranes of the cells become dry provides the same effect as detecting the point of time when the cell resistance starts increasing and the point of time when the cell voltage starts decreasing.
  • FIG. 3A, FIG. 3B and FIG. 3C are views schematically illustrating the water-containing state of a porous passage at the time indicated by the lines (1), (2) and (3), respectively, in the graph of FIG. 2.
  • FIG. 3A shows the water-containing state of a porous passage at the time indicated by the line (1) in the graph of FIG. 2.
  • a water passage which is formed as the water generated by the chemical reaction in the cell are drawn upward as viewed in the drawing by surface tension, capillary suction pressure and so on, and a gas passage, which is formed in the area other than the area where the water passage is formed to allow the fuel gas to flow therethrough, are formed in each porous passage.
  • the percentage of the water passage in the porous passage is high, which indicates that a large amount of water is contained in the porous passages.
  • the electrolyte membranes of the cell are kept moist.
  • FIG. 3B shows the water-containing state of a porous passage at the time indicated by the line (2) in the graph of FIG. 2. As shown in FIG. 3B, the percentage of the water passage in the porous passage is lower than that in the state shown in FIG. 3A, which indicates that the amount of water contained in the porous passages is smaller than that in the state shown in FIG. 3A.
  • FIG. 3C shows the water-containing state of a porous passage at the time indicated by the line (3) in the graph of FIG. 2.
  • FIG. 3C shows a state in which the percentage of the water passage in the porous passages is very low or no water passage is formed.
  • the ECU 20 of the fuel cell system of this embodiment calculates the pressure loss of the fuel gas from the difference between the pressure of the fuel gas detected by the pressure sensor 31 and the pressure of the anode off gas detect by the pressure sensor 33, and detects the point of time when the pressure loss starts decreasing.
  • the ECU 20 determines that the electrolyte membranes of the cells have started drying and starts the humidity control function as described before.
  • the ECU 20 In detecting the point of time when the pressure loss starts decreasing, the ECU 20 sequentially receives outputs from the pressure sensors 31 and 33, calculates the pressure loss from the pressure outputted from the pressure sensor 31 and the pressure outputted from the pressure sensor 33 at predetermined intervals (for example, every 10 seconds), and stores the calculated pressure loss values therein. Then, the ECU 20 detects a continuous decrease in the pressure loss with reference to a predetermined number of pressure loss values of the pressure loss values calculated at the predetermined intervals stored therein (for example, ten pressure loss values from the current calculated value in the sequence of pressure loss values).
  • An alternative method is to calculate the pressure loss sequentially and detect a continuous decrease in the pressure loss using values sampled from a plurality of calculated pressure loss values at predetermined intervals.
  • the method by which the ECU 20 detects a continuous decrease in the pressure loss is not specifically limited as long as it can be detected by some method.
  • the ECU 20 also refers to the coolant temperature detected by the temperature sensor 35 in order to detect a continuous decrease in the pressure loss due to drying of the electrolyte membranes of the cells reliably. More specifically, the ECU 20 determines that the electrolyte membranes of the cells have started drying when the coolant temperature is higher than a predetermined threshold temperature (80°, for example) and a continuous decrease in the pressure loss as described above is detected.
  • a predetermined threshold temperature 80°, for example
  • FIG. 4 is a flowchart of an example of operation involved in humidity control in the fuel cell system of this embodiment.
  • the fuel cell system of this embodiment is operating as follow.
  • the fuel gas supplied from the fuel gas supply device 21, the flow rate of which is controlled by the flow rate regulating valve 22, is introduced into the fuel cell stack 10 through the pipe 51.
  • the pressure sensor 31 detects the pressure of the fuel gas being introduced into the fuel cell stack 10 and transmits the detection result to the ECU 20.
  • the fuel gas supplied as described above and the oxidant gas humidified by the humidification module 12 and introduced into the fuel cell stack 10 through the pipe 43 are caused to react with each other via the electrolyte membrane to generate electricity.
  • the fuel gas which is not consumed for the generation of electricity is discharged from the fuel cell stack 10 as anode off gas.
  • the pressure sensor 33 detects the pressure of the anode off gas discharged from the fuel cell stack 10 and transmits the detection result to the ECU 20.
  • the cells generate heat when they generate electricity.
  • coolant cooled by the cooler 29 is introduced into the fuel cell stack 10.
  • the coolant absorbs heat from the cells in the fuel cell stack 10, and is discharged from the fuel cell stack 10.
  • the temperature sensor 35 detects the temperature of the coolant discharged from the fuel cell stack 10 and transmits the detection result to the ECU 20.
  • the ECU 20 receives output signals from the pressure sensors 31 and 33 and the temperature sensor 35.
  • the ECU 20 calculates the pressure loss of the fuel gas based on the pressure of the fuel gas and the pressure of the anode off gas as output signals from the pressure sensors 31 and 33 (S401).
  • the calculated pressure loss value is stored in the memory or the like.
  • the ECU 20 determines whether the pressure loss of the fuel gas is continuously decreasing with reference to the latest calculated pressure loss value and a predetermined number of pressure loss values stored (S402).
  • the ECU 20 determines whether the pressure loss of the fuel gas is continuously decreasing (S402; YES), the ECU 20 further determines whether the coolant temperature as an output signal from the temperature sensor 35 at this moment is higher than a predetermined threshold temperature (S403).
  • the ECU 20 determines that the pressure loss of the fuel gas is continuously decreasing (S402; YES) and that the coolant temperature at this moment is higher than the predetermined threshold temperature (S403; YES), the ECU 20 determines that some of the electrolyte membranes of the cells in the fuel cell stack 10 have dried (S404). If the ECU 20 determines that some of the electrolyte membranes have dried, the ECU 20 performs a specified humidity control function (S406). For example, the ECU 20 performs a control function to decrease the operating temperature of the fuel cell stack 10.
  • the ECU 20 determines that the pressure loss of the fuel gas is not continuously decreasing (S402; NO) or determines that the coolant temperature is not higher than the predetermined threshold temperature (S403; NO), the ECU 20 determines that the any of the electrolyte membranes of the cells in the fuel cell stack 10 has not dried yet (S405). [0082] The ECU 20 repeatedly performs the above operation.
  • the pressure of the fuel gas before being supplied to the fuel cell stack 10 is detected by the pressure sensor 31 disposed in the vicinity of the fuel gas inlet of the fuel cell stack 10, and the pressure of the anode off gas discharged from the fuel cell stack 10 is detected by the pressure sensor 33 disposed in the vicinity of the anode off gas outlet of the fuel cell stack 10. Based on the pressures of the fuel gas and the anode off gas detected by the pressure sensors 31 and 33, the pressure loss of the fuel gas which occurs when the fuel gas flows through the fuel cell stack 10 is calculated.
  • the pressure regulating valve 24 adjusts the pressures of the fuel gas and the anode off gas so that the pressures of the fuel gas and the anode off gas before and after passing through the fuel cell stack 10 can be the same.
  • the temperature of coolant supplied to the fuel cell stack 10 to cool the cells is detected by the temperature sensor 35 when the coolant is discharged from the fuel cell stack 10.
  • the detected coolant temperature is higher than a predetermined threshold temperature, it is determined that the cause of the continuous decrease in the pressure loss of the fuel gas is related to whether the electrolyte membranes become dry.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Fuel Cell (AREA)

Abstract

L'invention concerne un dispositif de commande (20) pour un système de pile à combustible, lequel dispositif a des moyens de mesure pour mesurer une perte de pression d'un gaz combustible dans un empilement de pile à combustible ; et des moyens de détermination pour déterminer qu'une membrane électrolytique dans un empilement de pile à combustible est sèche lorsqu'une diminution est détectée dans la perte de pression d'un gaz combustible mesurée par les moyens de mesure.
PCT/IB2008/001657 2007-05-21 2008-05-20 Dispositif de commande et procédé de commande pour système de pile à combustible WO2008142564A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2007-134250 2007-05-21
JP2007134250A JP2008288148A (ja) 2007-05-21 2007-05-21 燃料電池システムの制御装置

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WO2008142564A1 true WO2008142564A1 (fr) 2008-11-27

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Cited By (6)

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EP2383826A1 (fr) * 2008-12-26 2011-11-02 Toyota Jidosha Kabushiki Kaisha Dispositif d'estimation de la teneur en eau d'une pile à combustible et système de pile à combustible
WO2013167134A1 (fr) * 2012-05-07 2013-11-14 Aalborg Universitet Procédé de fonctionnement d'une pile à combustible
EP2742555A1 (fr) * 2011-08-11 2014-06-18 United Technologies Corporation Système de commande pour une centrale électrique à pile à combustible à champ d'écoulement d'agent de refroidissement hermétiquement scellé et ayant un réservoir d'eau
US9425473B2 (en) 2009-07-09 2016-08-23 Toyota Jidosha Kabushiki Kaisha Fuel cell system and method of operating fuel cell system
DE102016004855A1 (de) 2015-12-24 2017-06-29 Daimler Ag Verfahren zur Bestimmung eines Befeuchtungszustands einer Membran einer Brennstoffzelle und Brennstoffzellensystem
DE102021202053A1 (de) 2021-03-03 2022-09-08 Vitesco Technologies GmbH Diagnose zum Feuchtezustand eines PEM Brennstoffzellen-Stacks

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JP5541188B2 (ja) * 2011-02-16 2014-07-09 トヨタ自動車株式会社 燃料電池システム、燃料電池の運転方法
JP5500105B2 (ja) * 2011-02-28 2014-05-21 トヨタ自動車株式会社 燃料電池システム、燃料電池の運転方法及び電解質の乾燥度合い推定方法
JP6131942B2 (ja) * 2014-12-26 2017-05-24 トヨタ自動車株式会社 燃料電池システムおよび燃料電池の運転制御方法
JP6557124B2 (ja) * 2015-11-26 2019-08-07 株式会社豊田自動織機 燃料電池システム
JP6134832B1 (ja) * 2016-03-30 2017-05-24 東京瓦斯株式会社 燃料電池システム
JP7501396B2 (ja) * 2021-02-03 2024-06-18 トヨタ自動車株式会社 燃料電池システム

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US20060251943A1 (en) * 2004-12-28 2006-11-09 Matsushita Electric Industrial Co., Ltd. Polymer electrolyte fuel cell power generation system

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US20050175872A1 (en) * 2004-02-09 2005-08-11 Trabold Thomas A. Fuel cell flooding detection
US20060251943A1 (en) * 2004-12-28 2006-11-09 Matsushita Electric Industrial Co., Ltd. Polymer electrolyte fuel cell power generation system

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2383826A1 (fr) * 2008-12-26 2011-11-02 Toyota Jidosha Kabushiki Kaisha Dispositif d'estimation de la teneur en eau d'une pile à combustible et système de pile à combustible
EP2383826A4 (fr) * 2008-12-26 2013-01-23 Toyota Motor Co Ltd Dispositif d'estimation de la teneur en eau d'une pile à combustible et système de pile à combustible
US9425473B2 (en) 2009-07-09 2016-08-23 Toyota Jidosha Kabushiki Kaisha Fuel cell system and method of operating fuel cell system
EP2742555A1 (fr) * 2011-08-11 2014-06-18 United Technologies Corporation Système de commande pour une centrale électrique à pile à combustible à champ d'écoulement d'agent de refroidissement hermétiquement scellé et ayant un réservoir d'eau
EP2742555A4 (fr) * 2011-08-11 2015-04-08 United Technologies Corp Système de commande pour une centrale électrique à pile à combustible à champ d'écoulement d'agent de refroidissement hermétiquement scellé et ayant un réservoir d'eau
US9147898B2 (en) 2011-08-11 2015-09-29 Audi Ag Control system for a sealed coolant flow field fuel cell power plant having a water reservoir
WO2013167134A1 (fr) * 2012-05-07 2013-11-14 Aalborg Universitet Procédé de fonctionnement d'une pile à combustible
US9531017B2 (en) 2012-05-07 2016-12-27 Aalborg Universitet Method of operating a fuel cell
DE102016004855A1 (de) 2015-12-24 2017-06-29 Daimler Ag Verfahren zur Bestimmung eines Befeuchtungszustands einer Membran einer Brennstoffzelle und Brennstoffzellensystem
DE102021202053A1 (de) 2021-03-03 2022-09-08 Vitesco Technologies GmbH Diagnose zum Feuchtezustand eines PEM Brennstoffzellen-Stacks

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