WO2009115105A1 - Control method for controlling a fuel cell system and fuel cell system - Google Patents

Control method for controlling a fuel cell system and fuel cell system Download PDF

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Publication number
WO2009115105A1
WO2009115105A1 PCT/EP2008/002293 EP2008002293W WO2009115105A1 WO 2009115105 A1 WO2009115105 A1 WO 2009115105A1 EP 2008002293 W EP2008002293 W EP 2008002293W WO 2009115105 A1 WO2009115105 A1 WO 2009115105A1
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WO
WIPO (PCT)
Prior art keywords
fuel cell
cell system
storage device
control method
power
Prior art date
Application number
PCT/EP2008/002293
Other languages
French (fr)
Inventor
Patrick Bachinger
Clemens Boegershausen
Horst Michels
Joerg Schuetz
Herbert Schulze
Meenakshi Sundaresan
Hans-Frieder Walz
Original Assignee
Daimler Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daimler Ag filed Critical Daimler Ag
Priority to PCT/EP2008/002293 priority Critical patent/WO2009115105A1/en
Priority to DE112008003645T priority patent/DE112008003645T5/en
Publication of WO2009115105A1 publication Critical patent/WO2009115105A1/en

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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
    • H01M8/04298—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
    • H01M8/04955—Shut-off or shut-down 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
    • B60L58/33—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 cooling
    • 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
    • B60L58/40—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for controlling a combination of batteries and fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M16/00—Structural combinations of different types of electrochemical generators
    • H01M16/003—Structural combinations of different types of electrochemical generators of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers
    • H01M16/006—Structural combinations of different types of electrochemical generators of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers of fuel cells with rechargeable batteries
    • 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
    • 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
    • H01M8/04104—Regulation of differential pressures
    • 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
    • H01M8/04373—Temperature; Ambient temperature of auxiliary devices, e.g. reformers, compressors, burners
    • 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
    • H01M8/04783—Pressure differences, e.g. between anode and cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04097—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with recycling of the reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—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
    • H01M8/04395—Pressure; Ambient pressure; Flow 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
    • H01M8/04537—Electric variables
    • H01M8/04604—Power, energy, capacity or load
    • H01M8/04626—Power, energy, capacity or load of auxiliary devices, e.g. batteries, capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—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
    • H01M8/04664—Failure or abnormal function
    • 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
    • Y02E60/10—Energy storage using batteries
    • 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
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • 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 invention relates to a control method for controlling a fuel cell system. More specifically, the invention relates to a control method for controlling a fuel cell system which is operable to provide electric power for a consumer load, the fuel cell system comprising at least one fuel cell for generating electric power and at least one power storage device for storing the electric power, whereby the fuel cell system is switchable at least between a power mode, wherein the fuel cell generates electric power, and an idle mode, wherein the fuel cell is in a standby mode, wherein the control method comprises the step of enabling and/or disabling the idle mode, whereby the step of enabling and/or disabling the idle mode is determined by one or several state conditions of the fuel cell system.
  • the invention further relates to a fuel cell system for carrying out the control method.
  • Fuel cell systems are power generating units, which are - for example - used as mobile power generating units in vehicles.
  • Fuel cell systems commonly comprise at least one fuel cell, which is adapted for converting chemical energy in electrical energy. During this converting process a fuel, commonly hydrogen is catalytically processed with an oxidant, commonly oxygen, whereby the electric energy is generated.
  • a fuel cell system in connection with vehicles, it is known that using a hybrid- type fuel cell system, comprising fuel cells for generating electric energy and energy storage devices for temporarily storing the electric energy, offers some advantages in view of the efficiency of the fuel cell system.
  • the document US 2004/0013920 Al probably representing the closest prior art, discloses an idle control system for a fuel cell vehicle, whereby the fuel cell vehicle comprises a hybrid-type power supply unit with a fuel cell and a capacitor, being a power storage device.
  • the fuel cell vehicle can be controlled in a normal driving state, whereby the fuel cell is activated such that the fuel cell can supply current for the driving motor and further equipment and in an idle state, whereby the power generation by the fuel cell is stopped.
  • a control system activates the fuel cell to generate a current corresponding to the optimum power generation efficiency of the fuel cell.
  • a control method for controlling a fuel cell system with the features of claim 1 and a fuel cell system with the features of claim 7 are proposed. Preferred embodiments of the invention are disclosed by the dependent claims, the description and the figures. According to the invention a control method for controlling a fuel cell system, which is operable to provide electric power for a consumer load, is proposed.
  • the consumer load may be defined as a single load or as plurality of loads, for example a main load, like a motor of a vehicle, and auxiliary loads, like auxiliary fuel cell system and/or vehicle components .
  • control method is adapted to be used with a vehicle comprising the fuel cell system as a mobile power generation unit.
  • the fuel cell system comprises at least one fuel cell, preferably a plurality of fuel cell and especially more than 100 or 150 fuel cells, which are - in preferred embodiments - arranged in one or more fuel cell stacks.
  • Each fuel cell comprises an anode area, which is provided with a fuel gas, preferably hydrogen, and a cathode area, which is provided with an oxidant gas, preferably oxygen or ambient air, and which are separated from each other by a membrane, preferably a proton exchanging membrane (PEM).
  • PEM proton exchanging membrane
  • the fuel cell system further comprises at least one power storage device for storing the electric power generated by the at least one fuel cell.
  • the power storage device is preferably realized to store electric energy for providing the consumer load, especially the main load and/or the auxiliary loads, temporarily, preferably for at least one minute, preferably more than ten minutes with electric power.
  • the fuel cell system is switchable at least between a power mode and an idle mode.
  • the fuel cell In the power mode the fuel cell generates electric power, especially sufficient electric power for providing the consumer load, especially the main load, sufficiently.
  • the idle mode In the idle mode the fuel cell is in a standby mode, whereby no or only a small amount of electric power is generated.
  • none of the electric power generated by the fuel cell is used for charging the power storage device and/or for providing the consumer load, especially the main load.
  • the standby mode is initialized by stopping a fluid flow engine, especially an air compressor, which is arranged and/or adapted to provide the fuel cell with the oxidant.
  • a possible advantage of switching the fuel cell system in the idle mode and/or the fuel cell in the standby mode is to improve the fuel efficiency and/or noise/vibration/harshness characteristics of the fuel cell system.
  • the control method comprises a step of enabling and/or disabling the idle mode of the fuel cell system.
  • the step of enabling or disabling, respectively, is determined by and/or based on one or several state conditions of the fuel cell system.
  • the state conditions may comprise conditions concerning the operational state of the fuel cell system and/or concerning the single fuel cells and/or conditions of user interactions, like start/stop instructions, which may be generated automatically or manually.
  • the present invention proposes that at least one state condition refers to the temperature of the power storage device .
  • the lifetime of the power storage device can be increased by keeping its temperature device within a pre-determined and/or protective range.
  • the power storage device In the idle mode of the fuel cell system and/or in the standby mode of the fuel cell the power storage device is used to power at least the auxiliary loads and/or the main load while the fuel cell does not generate power, resulting in an increase in power storage device internal heat generation.
  • the internal heat or the temperature of the power storage device is monitored. In case the temperature is out of the pre-determined and/or protective range the power storage device can be protected by suitable means or actions.
  • the idle mode and/or the standby mode is only allowed in case the power storage device works at a pre-determined temperature and/or temperature range to prevent power storage device lifetime degradation.
  • the state condition is defined so that the idle mode is only enabled in case the storage device temperature is less than a predetermined lower value.
  • the lower value is preferably chosen to be under an optimum temperature of the power storage device, the optimum temperature being defined as a temperature providing a long or the longest lifetime of the power storage device.
  • the difference between the optimum temperature and the lower value is set to allow the power storage device to increase its temperature during the idle mode and/or standby mode, but still remaining within an allowed working range.
  • the state condition is defined so that the idle mode is disabled in case the storage device temperature is greater than a pre ⁇ determined upper value.
  • the upper value is chosen as a limiting value, preferably being above the optimum temperature value and/or being below of a critical temperature of the power storage device reducing the lifetime of the power storage device.
  • the lower value and/or the upper value and/or the optimum temperature value is/are 43°C.
  • the difference between the lower value and upper value is greater than 5°C, preferably greater than 1O 0 C, in order to provide the sufficient working range for the power storage device .
  • the further state conditions comprise one, a user-defined set, or all of the following state conditions, whereby the idle and/or standby mode is only permissible in case the further state conditions are fulfilled.:
  • the vehicle and fuel cell system, respectively, is NOT operating in pure battery mode and/or the vehicle and fuel cell system, respectively, is NOT operating in lean mode (i.e. in which the only power source being used is the fuel cell stack and the power storage device does not contribute to the power supply) .
  • the power storage device state-of-charge (SOC) is greater than a pre-determined value.
  • the power at an inverter is less than a pre-determined value .
  • E The drive-train current requirement is less than a pre ⁇ determined value.
  • F The cooling fluid temperature is greater than a predetermined value, especially greater than for example 80°C in order to prevent cold-start problems.
  • G The storage device calibration is NOT active.
  • H The time between each entry in a standby and/or idle mode is greater than a pre-determined range.
  • the speed of the air compressor is less than a predetermined value.
  • the vehicle speed is less than a pre-determined value.
  • control method is adapted, so that in the idle and/or standby mode the pressure of the fuel gas is higher than the pressure of oxidant gas and/or the atmospheric pressure or the ambient air, respectively.
  • this pressure difference is uphold during a complete idle and/or standby mode cycle and/or is actively supported by components of the fuel cell system.
  • One finding of this aspect is, that maintaining a pressure slightly higher on the hydrogen or anode side of the fuel cell as compared to the oxidant or cathode side of the fuel cell prevents crossover of oxygen to the anode side. As a positive consequence of the prevention of the crossover oxygen deficient condition on the cathode side and cathode corrosion are reduced or prevented. Furthermore, maintaining the hydrogen pressure slightly above atmospheric pressure ensures that restart from the standby mode is not degraded due to fuel starvation.
  • the pressure difference between the pressure of the fuel gas and the pressure of the oxidant gas and/or the atmospheric pressure is in a range between 0.1 bar and 0.4 bar, balancing the positive effects explained above and possible negative effects due to a too high pressure difference and thus mechanical stress on the membrane between cathode and anode side of the fuel cell.
  • a further subject-matter of the invention is a fuel cell system with the features of claim 7.
  • the fuel cell system comprises at least one fuel cell for generating electric power, at least one power storage device for storing the electric power and a control unit, the control unit being operable to switch the fuel cell system at least between a power mode, wherein the fuel cell generates electric power, and an idle mode, wherein the fuel cell is in a standby mode.
  • the fuel cell system is characterized by temperature means for estimating and/or measuring the operation temperature of the power device, whereby the temperature means is connected with the control unit and whereby the control unit is operable for using the control method according to one of the preceding claims or as described above.
  • the power storage device is preferably realized as a storage battery, especially as a high-voltage storage battery, working with a voltage greater than 100 V, preferably more than 150 V, or is realized as a capacitor or a super-cap.
  • the temperature means is embodied as a temperature sensor, measuring the operation or internal temperature of the power storage device.
  • the fuel cell system further comprises a DC/DC converter for electrically coupling the fuel cell with the storage device.
  • the DC/DC converter is operable for adapting the voltage of the fuel cell and the voltage of the power storage device.
  • the fuel cell system comprises a DC/AC inverter for converting the electric power from the fuel cell and/or the power storage device for the consumer load.
  • a fuel cell or at least a fuel cell is discussed, however, a plurality of fuel cells may be implemented, working together as one or more fuel cell stacks and/or as a single fuel cell.
  • the fuel cell system is adapted or realized for the use in a vehicle, providing electric power for the vehicle.
  • These fuel cell systems are also referred to as hybrid-type systems .
  • Fig. 1 is a schematic diagram of a fuel cell system according to the present invention
  • Fig. 2 is a schematic diagram showing details of the auxiliary components according to the present invention.
  • Fig. 3 is a flow chart showing a general method for permitting standby and executing intermittent operation
  • Fig. 4 is a flowchart showing the conditions under which standby is permitted
  • Fig. 5 is a flowchart showing the conditions under which the constellation of standby is emitted.
  • FIG. 1 shows a schematic diagram of a fuel cell system as an embodiment of the invention comprised of a fuel cell stack 1, with each cell of the stack containing an anode Ia and a cathode Ib, a hydrogen supply 2, an air supply 3 and a cooling loop 4.
  • the fuel cell system is adapted for providing electric power for a vehicle.
  • the hydrogen supply 2 may be realized as a tank or as a reformer unit.
  • the cooling loop 4 comprises a re-circulating cooling fluid, whereby the temperature of the cooling fluid is measured by a sensor unit 5.
  • Vehicle level components include a DC/DC converter 6 for a high voltage battery 7 used as secondary power source, both of which are cooled by a common cooling system 8.
  • An inverter 9 for transforming the electric power from the fuel cell 1 and/or the high voltage battery 7 into an AC mode.
  • a driving motor 10 for the vehicle, auxiliary components 11 and a vehicle controller 12 are parts of the fuel cell system, whereby the vehicle controller 12 is operable for controlling the auxiliary components 11.
  • the fuel cell stack 1 is electrically connected to the DC/DC converter 6 and inverter 9.
  • the DC/DC converter 6 converts the voltage of the fuel cell stack 1 electrical output and supplies the high voltage battery 7.
  • the fuel cell stack 1 outputs direct current which is converted to alternating current by the inverter 9 which is then supplied to the driving motor 10 and auxiliary component motors 11.
  • the high voltage battery 7 is a secondary power source for supplying electrical power to the drive motor 10 and auxiliary component motors 11.
  • the hydrogen supply 2 provides the fuel cell anode Ia with high pressure hydrogen.
  • the air supply 3 provides the fuel cell cathode Ib with high pressure air.
  • the cooling loop 4 circulates coolant in the fuel cell stack 1 to maintain temperature within the fuel cell at a pre-determined level.
  • the solid lines Ll refer to gas/liquid flow.
  • the rough dashed lines L2 refer to electric current, especially direct electric current, and the fine dashed lines L3 illustrate signal flows.
  • Fig. 2 shows a schematic diagram of the auxiliary component motors 11 in figure 1.
  • the exhaust hydrogen not used by the fuel cell stack 1 is returned to the fuel cell anode Ia using a blower 11a driven by a motor lib.
  • the cooling loop has a cooling pump lie driven by a motor Hd.
  • the air supply has a compressor He driven by a motor Hf.
  • the inverter 9 converts direct current into alternating current for the auxiliary component motors 11 from the fuel cell 1 and/or the high voltage battery 7 through the DC/DC converter 6.
  • the additional dot and dash lines L4 represent the flow of alternating electric current.
  • the stop phase or standby mode is enabled if several AND conditions are met shown in the flowchart of Fig. 3, Step Al. If all the AND conditions are not fulfilled, entry into standby is prohibited as represented in Step A2. If all the AND conditions are fulfilled, the controller 12 switches to the stop mode of the standby operation and the compressor motor Hf is shut off, i.e. the speed is set to 0 rpm as represented in Step A3.
  • Step A4 the DC/DC converter 6 holds the fuel cell stack 1 voltage within a pre-determined range. The lower end of the pre-determined range is set as the limit required by the vehicle auxiliaries still in operation.
  • the DC/DC converter 6 is also used during the stop mode of standby to set the voltage between the fuel cell stack 1 and the high voltage battery 7 such that stack current remains at zero amperes or very near zero amperes .
  • Step A5 it is assessed if it is time to enter into intermittent operation, whereby the compressor motor Hf is turned on, i.e. the speed is ramped up, but to a low level for a pre-determined duration as shown in Step A6.
  • the hydrogen blower motor Hb remains on but also at a low speed.
  • the high voltage battery provides the auxiliaries 11 such as the compressor motor Hf and hydrogen blower motor Hb with current during the standby operation. It is determined whether it is time to cancel standby as shown in Step A7.
  • Fig. 4 is a flowchart showing the detailed AND conditions, all of which must be fulfilled before the vehicle enters standby operation (Step BH) . If any of the conditions are not fulfilled, entry into standby is prohibited (Step B12) . As shown in step Bl, it must be determined if the vehicles is NOT operating in pure battery mode, if the vehicle is NOT operating in lean mode (i.e. in which the only power source being used is the fuel cell stack and the battery does not contribute to the power supply) or if a fuel cell system failure has NOT occurred. In Step B2 it must be determined if the battery state of charge (SOC) is greater than the pre ⁇ determined value.
  • SOC battery state of charge
  • Step B3 it must be determined if the power at the inverter is less than a pre-determined value.
  • Step B4 it must be determined if the drivetrain current requirement is less than a pre-determined value.
  • Step B5 it must be determined if the high voltage battery temperature is less than a pre-determined value.
  • Step B6 it must be determined if the cooling fluid temperature is greater than a pre-determined value.
  • Step B7 it must be determined if the high voltage battery calibration is NOT active.
  • Step B8 it must be determined if the time between each entry into standby is greater than the pre-determined range.
  • Step B9 it must be determined if the compressor speed is less than a pre-determined value.
  • Step BlO it must be determined if the vehicle speed is less than a pre-determined value.
  • Step C7 it must be determined if the high voltage battery SOC is less than a pre-determined value.
  • Step C2 it must be determined if the auxiliary loads at the inverter are greater than a pre-determined range.
  • Step C3 it must be determined if the drivetrain current is greater than a pre-determined value.
  • Step C4 it must be determined if the high voltage battery temperature is greater than a pre-determined value.
  • Step C5 it must be determined if the system load reduction is at a pre-determined level.
  • Step C6 it must be determined if the ignition is off.
  • one embodiment of the present invention is to prevent high voltage battery lifetime degradation by enabling standby when the high voltage battery temperature is less than a pre-determined value.
  • Additional indicators evaluated before entering into standby include: battery mode, fuel cell stack mode, fuel cell system failure status, battery SOC, power at the inverter, drivetrain current requirement, cooling fluid temperature, high voltage battery calibration status, time between each entry into standby, compressor speed, and vehicle speed.
  • An upper limit is set as a condition for exiting standby to prevent an overheat condition in the high voltage battery. Therefore, another embodiment of the present invention is to prevent high voltage battery lifetime degradation by disabling standby when the high voltage battery temperature is greater than a pre-determined value. Additional indicators evaluated before exiting standby include: battery SOC, power at the inverter, drivetrain current requirement, system load status, and ignition status. These indicators are described in more detail in the discussion of Fig. 5.

Abstract

It is one object of the present invention to provide a control method for controlling a fuel cell system and a fuel cell system operable for carrying out the control method, improving the operation of the fuel cell system. A control method for controlling a fuel cell system operable to provide electric power for a consumer load is proposed, the fuel cell system comprising at least one fuel cell for generating electric power and at least one power storage device for storing the electric power, whereby the fuel cell system is switchable at least between a power mode, wherein the fuel cell generates electric power, and an idle mode, wherein the fuel cell is in a standby mode, whereby the control method comprises the step of enabling and/or disabling the idle mode, whereby the step of enabling and/or disabling the idle mode is determined by one or several state conditions of the fuel cell system, whereby at least one state condition refers to the temperature of the power storage device.

Description

Control method for controlling a fuel cell system and fuel cell system
The invention relates to a control method for controlling a fuel cell system. More specifically, the invention relates to a control method for controlling a fuel cell system which is operable to provide electric power for a consumer load, the fuel cell system comprising at least one fuel cell for generating electric power and at least one power storage device for storing the electric power, whereby the fuel cell system is switchable at least between a power mode, wherein the fuel cell generates electric power, and an idle mode, wherein the fuel cell is in a standby mode, wherein the control method comprises the step of enabling and/or disabling the idle mode, whereby the step of enabling and/or disabling the idle mode is determined by one or several state conditions of the fuel cell system. The invention further relates to a fuel cell system for carrying out the control method.
Fuel cell systems are power generating units, which are - for example - used as mobile power generating units in vehicles. Fuel cell systems commonly comprise at least one fuel cell, which is adapted for converting chemical energy in electrical energy. During this converting process a fuel, commonly hydrogen is catalytically processed with an oxidant, commonly oxygen, whereby the electric energy is generated. Returning to the example of using a fuel cell system in connection with vehicles, it is known that using a hybrid- type fuel cell system, comprising fuel cells for generating electric energy and energy storage devices for temporarily storing the electric energy, offers some advantages in view of the efficiency of the fuel cell system.
The document US 2004/0013920 Al, probably representing the closest prior art, discloses an idle control system for a fuel cell vehicle, whereby the fuel cell vehicle comprises a hybrid-type power supply unit with a fuel cell and a capacitor, being a power storage device. In operation, the fuel cell vehicle can be controlled in a normal driving state, whereby the fuel cell is activated such that the fuel cell can supply current for the driving motor and further equipment and in an idle state, whereby the power generation by the fuel cell is stopped. In the said document it is proposed that in case the state of charge of the power storage device falls below a pre-determined state of charge during the idle state, a control system activates the fuel cell to generate a current corresponding to the optimum power generation efficiency of the fuel cell.
It is one object of the present invention to provide a control method for controlling a fuel cell system and a fuel cell system operable for carrying out the control method, improving the operation of the fuel cell system.
A control method for controlling a fuel cell system with the features of claim 1 and a fuel cell system with the features of claim 7 are proposed. Preferred embodiments of the invention are disclosed by the dependent claims, the description and the figures. According to the invention a control method for controlling a fuel cell system, which is operable to provide electric power for a consumer load, is proposed. The consumer load may be defined as a single load or as plurality of loads, for example a main load, like a motor of a vehicle, and auxiliary loads, like auxiliary fuel cell system and/or vehicle components .
Preferably, the control method is adapted to be used with a vehicle comprising the fuel cell system as a mobile power generation unit.
The fuel cell system comprises at least one fuel cell, preferably a plurality of fuel cell and especially more than 100 or 150 fuel cells, which are - in preferred embodiments - arranged in one or more fuel cell stacks. Each fuel cell comprises an anode area, which is provided with a fuel gas, preferably hydrogen, and a cathode area, which is provided with an oxidant gas, preferably oxygen or ambient air, and which are separated from each other by a membrane, preferably a proton exchanging membrane (PEM).
The fuel cell system further comprises at least one power storage device for storing the electric power generated by the at least one fuel cell. The power storage device is preferably realized to store electric energy for providing the consumer load, especially the main load and/or the auxiliary loads, temporarily, preferably for at least one minute, preferably more than ten minutes with electric power.
The fuel cell system is switchable at least between a power mode and an idle mode. In the power mode the fuel cell generates electric power, especially sufficient electric power for providing the consumer load, especially the main load, sufficiently. In the idle mode the fuel cell is in a standby mode, whereby no or only a small amount of electric power is generated. Preferably none of the electric power generated by the fuel cell is used for charging the power storage device and/or for providing the consumer load, especially the main load. Preferably the standby mode is initialized by stopping a fluid flow engine, especially an air compressor, which is arranged and/or adapted to provide the fuel cell with the oxidant.
A possible advantage of switching the fuel cell system in the idle mode and/or the fuel cell in the standby mode is to improve the fuel efficiency and/or noise/vibration/harshness characteristics of the fuel cell system.
The control method comprises a step of enabling and/or disabling the idle mode of the fuel cell system. The step of enabling or disabling, respectively, is determined by and/or based on one or several state conditions of the fuel cell system. The state conditions may comprise conditions concerning the operational state of the fuel cell system and/or concerning the single fuel cells and/or conditions of user interactions, like start/stop instructions, which may be generated automatically or manually.
The present invention proposes that at least one state condition refers to the temperature of the power storage device .
It is a finding of the invention that the lifetime of the power storage device can be increased by keeping its temperature device within a pre-determined and/or protective range. In the idle mode of the fuel cell system and/or in the standby mode of the fuel cell the power storage device is used to power at least the auxiliary loads and/or the main load while the fuel cell does not generate power, resulting in an increase in power storage device internal heat generation. According to the invention, the internal heat or the temperature of the power storage device is monitored. In case the temperature is out of the pre-determined and/or protective range the power storage device can be protected by suitable means or actions.
In one embodiment of the invention, the idle mode and/or the standby mode is only allowed in case the power storage device works at a pre-determined temperature and/or temperature range to prevent power storage device lifetime degradation.
In a preferred embodiment of the invention the state condition is defined so that the idle mode is only enabled in case the storage device temperature is less than a predetermined lower value. The lower value is preferably chosen to be under an optimum temperature of the power storage device, the optimum temperature being defined as a temperature providing a long or the longest lifetime of the power storage device. The difference between the optimum temperature and the lower value is set to allow the power storage device to increase its temperature during the idle mode and/or standby mode, but still remaining within an allowed working range.
In an additional or alternative aspect of the invention the state condition is defined so that the idle mode is disabled in case the storage device temperature is greater than a pre¬ determined upper value. The upper value is chosen as a limiting value, preferably being above the optimum temperature value and/or being below of a critical temperature of the power storage device reducing the lifetime of the power storage device.
In yet another preferred realization of the invention the lower value and/or the upper value and/or the optimum temperature value is/are 43°C. However, it is also preferred that the difference between the lower value and upper value is greater than 5°C, preferably greater than 1O0C, in order to provide the sufficient working range for the power storage device .
In a further embodiment of the invention it is preferred that the further state conditions comprise one, a user-defined set, or all of the following state conditions, whereby the idle and/or standby mode is only permissible in case the further state conditions are fulfilled.:
A: The vehicle and fuel cell system, respectively, is NOT operating in pure battery mode and/or the vehicle and fuel cell system, respectively, is NOT operating in lean mode (i.e. in which the only power source being used is the fuel cell stack and the power storage device does not contribute to the power supply) .
B: A fuel cell system failure is NOT active.
C: The power storage device state-of-charge (SOC) is greater than a pre-determined value.
D: The power at an inverter is less than a pre-determined value .
E: The drive-train current requirement is less than a pre¬ determined value. F: The cooling fluid temperature is greater than a predetermined value, especially greater than for example 80°C in order to prevent cold-start problems.
G: The storage device calibration is NOT active.
H: The time between each entry in a standby and/or idle mode is greater than a pre-determined range.
I: The speed of the air compressor is less than a predetermined value.
J: The vehicle speed is less than a pre-determined value.
According to another aspect of the invention the control method is adapted, so that in the idle and/or standby mode the pressure of the fuel gas is higher than the pressure of oxidant gas and/or the atmospheric pressure or the ambient air, respectively. Preferably, this pressure difference is uphold during a complete idle and/or standby mode cycle and/or is actively supported by components of the fuel cell system.
One finding of this aspect is, that maintaining a pressure slightly higher on the hydrogen or anode side of the fuel cell as compared to the oxidant or cathode side of the fuel cell prevents crossover of oxygen to the anode side. As a positive consequence of the prevention of the crossover oxygen deficient condition on the cathode side and cathode corrosion are reduced or prevented. Furthermore, maintaining the hydrogen pressure slightly above atmospheric pressure ensures that restart from the standby mode is not degraded due to fuel starvation. In a preferred realization of the invention the pressure difference between the pressure of the fuel gas and the pressure of the oxidant gas and/or the atmospheric pressure is in a range between 0.1 bar and 0.4 bar, balancing the positive effects explained above and possible negative effects due to a too high pressure difference and thus mechanical stress on the membrane between cathode and anode side of the fuel cell.
A further subject-matter of the invention is a fuel cell system with the features of claim 7. The fuel cell system comprises at least one fuel cell for generating electric power, at least one power storage device for storing the electric power and a control unit, the control unit being operable to switch the fuel cell system at least between a power mode, wherein the fuel cell generates electric power, and an idle mode, wherein the fuel cell is in a standby mode. The fuel cell system is characterized by temperature means for estimating and/or measuring the operation temperature of the power device, whereby the temperature means is connected with the control unit and whereby the control unit is operable for using the control method according to one of the preceding claims or as described above.
The power storage device is preferably realized as a storage battery, especially as a high-voltage storage battery, working with a voltage greater than 100 V, preferably more than 150 V, or is realized as a capacitor or a super-cap.
Preferably, the temperature means is embodied as a temperature sensor, measuring the operation or internal temperature of the power storage device. In a preferred realization of the invention the fuel cell system further comprises a DC/DC converter for electrically coupling the fuel cell with the storage device. The DC/DC converter is operable for adapting the voltage of the fuel cell and the voltage of the power storage device.
As an alternative or additionally the fuel cell system comprises a DC/AC inverter for converting the electric power from the fuel cell and/or the power storage device for the consumer load. Although a fuel cell or at least a fuel cell is discussed, however, a plurality of fuel cells may be implemented, working together as one or more fuel cell stacks and/or as a single fuel cell.
In a preferred embodiment the fuel cell system is adapted or realized for the use in a vehicle, providing electric power for the vehicle. These fuel cell systems are also referred to as hybrid-type systems .
Further details and advantages of the invention will become apparent by the following description and the attached figures of preferred embodiments of the invention. The figures show:
Fig. 1 is a schematic diagram of a fuel cell system according to the present invention;
Fig. 2 is a schematic diagram showing details of the auxiliary components according to the present invention;
Fig. 3 is a flow chart showing a general method for permitting standby and executing intermittent operation; Fig. 4 is a flowchart showing the conditions under which standby is permitted;
Fig. 5 is a flowchart showing the conditions under which the constellation of standby is emitted.
Figure 1 shows a schematic diagram of a fuel cell system as an embodiment of the invention comprised of a fuel cell stack 1, with each cell of the stack containing an anode Ia and a cathode Ib, a hydrogen supply 2, an air supply 3 and a cooling loop 4. The fuel cell system is adapted for providing electric power for a vehicle. The hydrogen supply 2 may be realized as a tank or as a reformer unit. The cooling loop 4 comprises a re-circulating cooling fluid, whereby the temperature of the cooling fluid is measured by a sensor unit 5.
Vehicle level components include a DC/DC converter 6 for a high voltage battery 7 used as secondary power source, both of which are cooled by a common cooling system 8. An inverter 9 for transforming the electric power from the fuel cell 1 and/or the high voltage battery 7 into an AC mode. Furthermore a driving motor 10 for the vehicle, auxiliary components 11 and a vehicle controller 12 are parts of the fuel cell system, whereby the vehicle controller 12 is operable for controlling the auxiliary components 11.
The fuel cell stack 1 is electrically connected to the DC/DC converter 6 and inverter 9. The DC/DC converter 6 converts the voltage of the fuel cell stack 1 electrical output and supplies the high voltage battery 7. The fuel cell stack 1 outputs direct current which is converted to alternating current by the inverter 9 which is then supplied to the driving motor 10 and auxiliary component motors 11. The high voltage battery 7 is a secondary power source for supplying electrical power to the drive motor 10 and auxiliary component motors 11. The hydrogen supply 2 provides the fuel cell anode Ia with high pressure hydrogen. The air supply 3 provides the fuel cell cathode Ib with high pressure air. The cooling loop 4 circulates coolant in the fuel cell stack 1 to maintain temperature within the fuel cell at a pre-determined level.
The solid lines Ll refer to gas/liquid flow. The rough dashed lines L2 refer to electric current, especially direct electric current, and the fine dashed lines L3 illustrate signal flows.
Fig. 2 shows a schematic diagram of the auxiliary component motors 11 in figure 1. The exhaust hydrogen not used by the fuel cell stack 1 is returned to the fuel cell anode Ia using a blower 11a driven by a motor lib. The cooling loop has a cooling pump lie driven by a motor Hd. The air supply has a compressor He driven by a motor Hf. The inverter 9 converts direct current into alternating current for the auxiliary component motors 11 from the fuel cell 1 and/or the high voltage battery 7 through the DC/DC converter 6. The additional dot and dash lines L4 represent the flow of alternating electric current.
The stop phase or standby mode is enabled if several AND conditions are met shown in the flowchart of Fig. 3, Step Al. If all the AND conditions are not fulfilled, entry into standby is prohibited as represented in Step A2. If all the AND conditions are fulfilled, the controller 12 switches to the stop mode of the standby operation and the compressor motor Hf is shut off, i.e. the speed is set to 0 rpm as represented in Step A3. In Step A4 , the DC/DC converter 6 holds the fuel cell stack 1 voltage within a pre-determined range. The lower end of the pre-determined range is set as the limit required by the vehicle auxiliaries still in operation. The DC/DC converter 6 is also used during the stop mode of standby to set the voltage between the fuel cell stack 1 and the high voltage battery 7 such that stack current remains at zero amperes or very near zero amperes .
As shown in Fig. 3 Step A5 it is assessed if it is time to enter into intermittent operation, whereby the compressor motor Hf is turned on, i.e. the speed is ramped up, but to a low level for a pre-determined duration as shown in Step A6. During the entire standby operation the hydrogen blower motor Hb remains on but also at a low speed. The high voltage battery provides the auxiliaries 11 such as the compressor motor Hf and hydrogen blower motor Hb with current during the standby operation. It is determined whether it is time to cancel standby as shown in Step A7.
Fig. 4 is a flowchart showing the detailed AND conditions, all of which must be fulfilled before the vehicle enters standby operation (Step BH) . If any of the conditions are not fulfilled, entry into standby is prohibited (Step B12) . As shown in step Bl, it must be determined if the vehicles is NOT operating in pure battery mode, if the vehicle is NOT operating in lean mode (i.e. in which the only power source being used is the fuel cell stack and the battery does not contribute to the power supply) or if a fuel cell system failure has NOT occurred. In Step B2 it must be determined if the battery state of charge (SOC) is greater than the pre¬ determined value. In Step B3 it must be determined if the power at the inverter is less than a pre-determined value. In Step B4 it must be determined if the drivetrain current requirement is less than a pre-determined value. In Step B5 it must be determined if the high voltage battery temperature is less than a pre-determined value. In Step B6 it must be determined if the cooling fluid temperature is greater than a pre-determined value. In Step B7 it must be determined if the high voltage battery calibration is NOT active. In Step B8 it must be determined if the time between each entry into standby is greater than the pre-determined range. In Step B9 it must be determined if the compressor speed is less than a pre-determined value. In Step BlO it must be determined if the vehicle speed is less than a pre-determined value.
Fig. 5 shows the steps necessary to cancel standby. As these steps represent OR conditions, any of the steps can trigger exit from standby (Step C7), otherwise the vehicle remains in standby (Step C8) . In Step Cl it must be determined if the high voltage battery SOC is less than a pre-determined value. In Step C2 it must be determined if the auxiliary loads at the inverter are greater than a pre-determined range. In Step C3 it must be determined if the drivetrain current is greater than a pre-determined value. In Step C4 it must be determined if the high voltage battery temperature is greater than a pre-determined value. In Step C5 it must be determined if the system load reduction is at a pre-determined level. In Step C6 it must be determined if the ignition is off.
In standby the high voltage battery is used to power auxiliaries while the fuel cell stack does not generate power, resulting in an increase in battery internal heat generation. A lower limit is set as a condition for entering standby to allow for an expected increase during standby. Therefore, one embodiment of the present invention is to prevent high voltage battery lifetime degradation by enabling standby when the high voltage battery temperature is less than a pre-determined value. Additional indicators evaluated before entering into standby include: battery mode, fuel cell stack mode, fuel cell system failure status, battery SOC, power at the inverter, drivetrain current requirement, cooling fluid temperature, high voltage battery calibration status, time between each entry into standby, compressor speed, and vehicle speed. These indicators were described in more detail in the discussion of Fig. 4.
An upper limit is set as a condition for exiting standby to prevent an overheat condition in the high voltage battery. Therefore, another embodiment of the present invention is to prevent high voltage battery lifetime degradation by disabling standby when the high voltage battery temperature is greater than a pre-determined value. Additional indicators evaluated before exiting standby include: battery SOC, power at the inverter, drivetrain current requirement, system load status, and ignition status. These indicators are described in more detail in the discussion of Fig. 5.

Claims

Claims
1. Control method for controlling a fuel cell system operable to provide electric power for a consumer load (10, 11),
the fuel cell system comprising at least one fuel cell (1) for generating electric power and at least one power storage device (7) for storing the electric power, whereby the fuel cell system is switchable at least between a power mode, wherein the fuel cell (1) generates electric power, and an idle mode, wherein the fuel cell (1) is in a standby mode,
whereby the control method comprises the step of enabling and/or disabling the idle mode,
whereby the step of enabling and/or disabling the idle mode is determined by one or several state conditions of the fuel cell system,
characterized in that
at least one state condition refers to the temperature of the power storage device (7).
2. Control method according to claim 1, characterized in that the idle mode is enabled in case the power storage device temperature is less than a pre-determined lower value.
3. Control method according to claim 1 or 2, characterized in that the idle mode is disabled in case the power storage device temperature is greater than a predetermined upper value.
4. Control method according to one of the preceding claims, characterized in that the lower value and/or the upper value is/are 43°C.
5. Control method according to one of the preceding claims, characterized in that the difference between lower value and upper value is greater than 5°C, preferably greater than 100C.
6. Control method according to one of the preceding claims, characterized in that further conditions comprise one, a set of or all of the following state conditions:
- The fuel cell system is NOT operating in pure battery mode and/or the fuel cell system is NOT operating in lean mode ;
- A fuel cell system failure is NOT active;
- The power storage device state-of-charge (SOC) is greater than a pre-determined value;
- The power at an inverter is less than a pre-determined value;
- The drive-train current requirement is less than a pre- determined value;
- The cooling fluid temperature is greater than a predetermined value;
- The storage device calibration is NOT active;
- The time between each entry in a standby and/or idle mode is greater than a pre-determined range;
- The speed of the air compressor is less than a predetermined value.
- The vehicle speed is less than a pre-determined value.
7. Fuel cell system comprising
at least one fuel cell (1) for generating electric power,
at least one power storage device (7) for storing the electric power, and
a control unit (12), the control unit (12) being operable to switch the fuel cell system at least between a power mode, wherein the fuel cell generates electric power, and an idle mode, wherein the fuel cell is in a standby mode,
characterized by a
temperature means for estimating and/or measuring the temperature of the power storage device (7), whereby the temperature means is connected with the control unit (12) and whereby the control unit (12) is operable for using the control method according to one of the preceding claims .
8. Fuel cell system according to claim 7, characterized in that the temperature means are embodied as a temperature sensor.
9. Fuel cell system according to claim 7 or 8, characterized in that the power storage device (7) is a battery or a capacitor.
10. Fuel cell system according to one of the claims 7 to 9, the fuel cell system further comprising a DC/DC converter (6) for coupling the fuel cell with the storage device and/or a DC/AC inverter (9) for converting the electric power from the fuel cell and/or the storage device for the consumer load (10, 11).
11. Fuel cell system according to one of the claims 7 to 10, characterized in being adapted for the use in a vehicle.
PCT/EP2008/002293 2008-03-20 2008-03-20 Control method for controlling a fuel cell system and fuel cell system WO2009115105A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4106059A3 (en) * 2021-06-16 2023-11-08 Hyster-Yale Group, Inc. Systems and methods for determining a stack current request based on fuel cell operational conditions

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1275553A2 (en) * 2001-06-15 2003-01-15 Toyota Jidosha Kabushiki Kaisha Power output device with fuel cell and method therefor
WO2004082040A2 (en) * 2003-03-14 2004-09-23 Nissan Motor Co., Ltd. Fuel cell system and control method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004056868A (en) 2002-07-17 2004-02-19 Honda Motor Co Ltd Idling control equipment of fuel cell vehicle

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1275553A2 (en) * 2001-06-15 2003-01-15 Toyota Jidosha Kabushiki Kaisha Power output device with fuel cell and method therefor
WO2004082040A2 (en) * 2003-03-14 2004-09-23 Nissan Motor Co., Ltd. Fuel cell system and control method

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
BRETT ET AL: "System modelling and integration of an intermediate temperature solid oxide fuel cell and ZEBRA battery for automotive applications", JOURNAL OF POWER SOURCES, ELSEVIER, AMSTERDAM, NL, vol. 163, no. 1, 4 January 2007 (2007-01-04), pages 514 - 522, XP005738373, ISSN: 0378-7753 *
LEE J H ET AL: "Development of the control logic for the 42 V HEV system", APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION, 2005. APEC 2005. TWENTIETH ANNUAL IEEE AUSTIN, TX, USA 6-10 MARCH 2005, PISCATAWAY, NJ, USA,IEEE, US, vol. 2, 6 March 2005 (2005-03-06), pages 1009 - 1014Vol.2, XP010809359, ISBN: 978-0-7803-8975-5 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4106059A3 (en) * 2021-06-16 2023-11-08 Hyster-Yale Group, Inc. Systems and methods for determining a stack current request based on fuel cell operational conditions

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