WO2011151700A1 - Appareil de surveillance de tension et procédé de surveillance de tension - Google Patents

Appareil de surveillance de tension et procédé de surveillance de tension Download PDF

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Publication number
WO2011151700A1
WO2011151700A1 PCT/IB2011/001183 IB2011001183W WO2011151700A1 WO 2011151700 A1 WO2011151700 A1 WO 2011151700A1 IB 2011001183 W IB2011001183 W IB 2011001183W WO 2011151700 A1 WO2011151700 A1 WO 2011151700A1
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WO
WIPO (PCT)
Prior art keywords
fuel cell
voltage
power supply
side power
voltages
Prior art date
Application number
PCT/IB2011/001183
Other languages
English (en)
Inventor
Kazuya Mori
Original Assignee
Toyota Jidosha Kabushiki Kaisha
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 Toyota Jidosha Kabushiki Kaisha filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2011151700A1 publication Critical patent/WO2011151700A1/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
    • H01M8/04298—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
    • H01M8/04544—Voltage
    • H01M8/04552—Voltage of the individual fuel cell
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
    • 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
    • H01M8/04298—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
    • H01M8/04544—Voltage
    • H01M8/04559—Voltage of 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
    • H01M8/04858—Electric variables
    • H01M8/04925—Power, energy, capacity or load
    • H01M8/04947—Power, energy, capacity or load of auxiliary devices, e.g. batteries, capacitors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G01R31/3835—Arrangements for monitoring battery or accumulator variables, e.g. SoC involving only voltage measurements
    • 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
    • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
    • H01M8/249—Grouping of fuel cells, e.g. stacking of fuel cells comprising two or more groupings of fuel cells, e.g. modular assemblies
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/10—Control circuit supply, e.g. means for supplying power to the control circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/30—The power source being a fuel cell
    • 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

Definitions

  • the invention relates to a voltage monitoring apparatus and a voltage monitoring method for a fuel cell stack including a plurality of fuel cells connected in series.
  • fuel cells are typically provided in the form of a fuel cell stack in which the fuel cells are connected in series, in order to output a required high voltage.
  • a voltage monitoring apparatuses for monitoring the voltage of each fuel cell of a fuel cell stack have been proposed (for example, refer to Japanese Patent Application Publication NO. 2007-184135).
  • Japanese Patent Application Publication No. 2007-184135 describes a voltage monitoring apparatus that is structured to perform voltage monitoring for each of two or more divisional groups of fuel cells of a fuel cell stack. More specifically, cell voltage measurement circuits are provided for the respective fuel cell groups, and each cell voltage measurement circuit measures, for voltage monitoring, the voltages of the respective fuel cells belonging to the corresponding fuel cell group. It is to be noted that such cell voltage measurement circuits are typically powered by a secondary battery. More specifically, for example, DC-DC converters are provided for the respective cell voltage measurement circuits, and the voltage supplied from the secondary battery is converted into positive voltages and negative voltages using the respective DC-DC converters, and then they are supplied to the respective cell voltage measurement circuits.
  • the secondary battery is charged with the power supplied from the fuel cell stack, etc., and the power loss caused by the charging is not small, lowering the power efficiency.
  • the invention provides a voltage monitoring apparatus and a voltage monitoring method that suppress the power loss.
  • the first aspect of the invention relates to a voltage monitoring apparatus for a fuel cell stack including a plurality of fuel cells that are connected in series and are divided into two or more fuel cell groups.
  • the voltage monitoring apparatus includes: detection circuits which are provided for the respective fuel cell groups and each of which is driven with a positive side power supply voltage and a negative side power supply voltage, detects voltages of the respective fuel cells belonging to the corresponding fuel cell group, and outputs information obtained based on .the detected voltages; connection paths via which the detection circuits are connected, respectively, to fuel cell combinations, and via which the detection circuits are supplied with the positive side power supply voltages and the negative side power supply voltages from the respective fuel cell combinations, the fuel cell combinations constituting at least a portion of the fuel cell stack; a power supply portion that supplies the positive side power supply voltages and the negative side power supply voltages to the respective detection circuits; and a control portion that switches voltage supply to the detection circuits between voltage supply via the connection paths and voltage supply using the power supply portion, in accordance with a pre
  • the positive side power supply voltages and the negative side power supply voltages can be supplied to the detection circuits from the power supply portion and from, via the connection paths, the respective fuel cell combinations constituting at least a portion of the fuel cell stack.
  • the voltage supply to the detection circuits can be switched between the voltage supply using the power supply portion and the voltage supply using the respective fuel cell combinations (i.e., the voltage supply via the connection paths).
  • the above-mentioned voltage supply switching performed by the control portion reduces the cases where the positive side power supply voltages and the negative side power supply voltages are supplied to the detection circuits using the power supply portion. Accordingly, the voltage monitoring apparatus described above provides an advantage that the power loss can be suppressed.
  • the voltage monitoring apparatus described above may be such that the control portion includes a determination portion that determines whether all outputs of all the fuel cell groups in the fuel cell stack are appropriate; and a switchover execution portion that causes the voltage supply to be performed via the connection paths when the determination portion has determined that all the outputs of all the fuel cell groups in the fuel cell stack are appropriate, and that causes the voltage supply to be performed using the power supply portion when the determination portion has determined that not all the outputs of all the fuel cell groups in the fuel cell stack are appropriate.
  • the voltage supply to the detection circuits is performed via the connection paths only when all the outputs of all the fuel cell groups in the fuel cell stack are appropriate, that is, the power supply portion is used to supply the positive side power supply voltages and the negative side power supply voltages to the detection circuits if any of the outputs of all the fuel cell groups is ⁇ not appropriate. In this way, it is possible to prevent the voltage supply to the detection circuits from being performed using the fuel cell combination or combinations the outputs of which are not appropriate.
  • the voltage monitoring apparatus described above may be such that each of the fuel cell combinations is included in the fuel cell group corresponding to the detection circuit to which the fuel cell combination supplies the positive side power supply voltage and the negative side power supply voltage.
  • the detections circuits can each be powered by the fuel cells belonging to the corresponding fuel cell group.
  • connection paths include: positive connection lines via each of which a positive power supply terminal of the detection circuit corresponding to one of the fuel cell groups excluding the fuel cell group at a most positive side and the fuel cell group at a most negative side is connected to the fuel cell combination included in the fuel cell group located on a positive side of the fuel cell group to which the detection circuit corresponds; and negative connection lines via each of which a negative power supply terminal of the detection circuit corresponding to one of the fuel cell groups excluding the fuel cell group at the most positive side and the fuel cell group at the most negative side is connected to the fuel cell combination included in the fuel cell group located on a negative side of the fuel cell group to which the detection circuit corresponds.
  • At least one of the detection circuits can be powered by the fuel cell belonging to the fuel cell group located on the positive side of the fuel cell group to which the detection circuit corresponds and by the fuel cell belonging to the fuel cell group located on the negative side of the fuel cell group to which the detection circuit corresponds.
  • the difference between the positive side power supply voltage and negative side power supply voltage to be supplied to at least one of the detection circuits can be increased.
  • the voltage monitoring apparatus described above may be such that the power supply portion includes a secondary battery and voltage converters that are provided for the respective detection circuits, and each of the voltage converters converts an output voltage of the secondary battery into the positive side power supply voltage and the negative side power supply voltage to be supplied to the corresponding detection circuit.
  • the positive side power supply voltages and the negative side power supply voltages regulated by the respective voltage converters can be supplied to the detection circuits.
  • the voltage monitoring apparatus described above may be such that the power supply portion includes resistors that are provided for the respective detection circuits and are used for voltage division of a predetermined power supply voltage.
  • the positive side power supply voltage and negative side power supply voltage regulated through the voltage division performed by the resistors can be supplied to each detection circuit.
  • the voltage monitoring apparatus described above may be such that the predetermined power supply voltage is a total voltage of the fuel cell stack.
  • the total voltage of the fuel cell stack does not significantly decrease even when the voltage output from one of the fuel cell groups has decreased or is decreasing. According to the structure described above, therefore, the positive side power supply voltages and the negative side power supply voltages can be supplied using such a stable output of the fuel cell stack.
  • the voltage monitoring apparatus described above may be such that the power supply portion further includes a secondary battery and a voltage converter that converts an output voltage of the secondary battery into the predetermined power supply voltage.
  • the positive side power supply voltages and the negative side power supply voltages can be supplied using the secondary battery and the voltage converter.
  • the second aspect of the invention relates to a voltage monitoring method for a fuel cell system that includes a fuel cell stack including a plurality of fuel cells divided into two or more fuel cell groups; detection circuits which are provided for the respective fuel cell groups and each of which is driven with a positive side power supply voltage and a negative side power supply voltage, detects voltages of the respective fuel cells belonging to the corresponding fuel cell group, and outputs information obtained based on the detected voltages; connection paths via which the detection circuits are connected, respectively, to fuel cell combinations, and via which the detection circuits are supplied with the positive side power supply voltages and the negative side power supply voltages from the respective fuel cell combinations, the fuel cell combinations constituting at least a portion of the fuel cell stack; and a power supply portion that supplies the positive side power supply voltages and the negative side power supply voltages to the respective detection circuits.
  • the voltage monitoring method includes switching voltage supply to the detection circuits between voltage supply via the connection paths and voltage supply using the power supply portion, in accordance with a predetermined condition.
  • FIG. 1 is a view schematically showing the configuration of the voltage monitoring apparatus 10 of the first example embodiment
  • FIG. 2 is a flowchart illustrating the switching procedure that is executed by the control circuit 80 in the first example embodiment
  • FIG. 3 is a view schematically showing the configuration of the voltage monitoring apparatus 110 of the second example embodiment
  • FIG 4 is a view schematically showing the configuration of the voltage monitoring apparatus 210 of the fourth example embodiment
  • FIG. 5 is a view schematically showing the configuration of the voltage monitoring apparatus 410 as a modified version of the fourth example embodiment.
  • FIG 6 is a view schematically showing the configuration of the voltage monitoring apparatus 310 of the fifth example embodiment.
  • FIG. 1 schematically shows the configuration of a voltage monitoring apparatus 10 of the first example embodiment of the invention.
  • the voltage monitoring apparatus 10 is used to monitor the voltage of a fuel cell stack FCS constituted of a plurality of fuel cells stacked. It is to be noted that “fuel cell” is so called “single cell”, which is the minimum power generation element.
  • the fuel cells in the first example embodiment are solid polymer fuel cells each including: a membrane-electrode assembly (MEA) having an electrolyte membrane that is a thin membrane made of a solid polymer material exhibiting a high proton conductivity in a wet state, a cathode that is provided on one side of the electrolyte membrane, and an anode that is provided on the other side of the electrolyte membrane; gas diffusion layers; passage members; and separators, the gas diffusion layers, passage members, and separators being stacked on the respective surfaces of the membrane-electrode assembly (not shown in the drawings).
  • MEA membrane-electrode assembly
  • the fuel cell stack FCS is clamped by terminals, insulators, and end plates that are provided, respectively, at the both longitudinal ends of the fuel cell stack FCS.
  • the fuel cell stack FCS is connected to a supply-discharge system that supplies and discharges fuel gas, oxidizing gas, and coolant (not shown in the drawings).
  • the rated output of the fuel cell stack FCS in the first example embodiment is 300 V.
  • the rated output may be appropriately set and the number of fuel cells of the fuel cell stack FCS may be any number as long as it is two or more.
  • the fuel cell stack FCS is constituted of 12 fuel cells, i.e., fuel cells FC1 to FC12.
  • the fuel cells FC1 to FC12 constituting the fuel cell stack FCS are divided into three fuel cell groups Bl to B3 (will hereinafter be referred to as "fuel cell blocks Bl to B3"). While the fuel cells FC1 to FC12 are provided in the three fuel cell blocks in the first example embodiment, the number of fuel cell blocks may be any number as long as it is two or more. Further, although the number of the fuel cells of each of the fuel cell blocks Bl to B3 is four in the first example embodiment, each fuel cell block may have a different number of fuel cells. Further, although the number of the fuel cells of each fuel cell block is set to four for descriptive convenience, it may be changed to, for example, about 20 in practice.
  • each fuel cell block is not limited to any specific number.
  • the fuel cell combinations may constitute at least a portion of the fuel cell stack, and each of the fuel cell combinations may be included in the fuel cell group corresponding to the detection circuit to which the fuel cell combination supplies the positive side power supply voltage and the negative side power supply voltage.
  • the voltage monitoring apparatus 10 which is connected to the fuel cell stack FCS described above, includes voltage measurement circuits 21, 22, and 23, DC-DC converters 41, 42, and 43, a battery 70, and a control circuit 80.
  • the number of voltage measurement circuits i.e., the voltage measurement circuits 21, 22, and 23, is equal to the number of fuel cell blocks, i.e., the fuel cell blocks Bl to B3, and the voltage measurement circuits 21, 22, and 23 correspond, respectively, to the fuel cell blocks Bl to B3.
  • the voltage measurement circuits 21, 22, and 23 are connected, respectively, to the fuel cell blocks Bl to B3. More specifically, the first voltage measurement circuit 21 is connected to the fuel cells FC1 to FC4 belonging to the first fuel cell block Bl, the second voltage measurement circuit 22 is connected to the fuel cells FC5 to FC8 belonging to the second fuel cell block B2, and the third voltage measurement circuit 23 is connected to the fuel cells FC9 to FC12 belonging to the third fuel cell block B3.
  • the voltage measurement circuits 21, 22, and 23 are each driven with a positive side power supply voltage Vc and a negative side power supply voltage Vs.
  • the voltage measurement circuits 21, 22, and 23 each measure the voltages (output voltages) of the respective fuel cells connected thereto.
  • the voltage measurement circuits 21, 22, and 23 each serve as "detection circuit" that outputs the information obtained based on the detected voltages. In the first example embodiment, the lowest of the output voltages of the fuel cells of each fuel cell block is extracted as the information to be output.
  • the information output from each of the voltage measurement circuits 21, 22, and 23 is not limited to such information on the lowest output voltage, that is, it may alternatively be information on other value or values, such as the highest of the output voltages of the fuel cells of each fuel cell block and the average of the output voltages of the fuel cells of each fuel cell block. That is, the information output from each of the voltage measurement circuits 21, 22, and 23 may be any information as long as it is obtained based on the output voltages of the respective fuel cells, such as information indicating that the lowest output voltage has become lower than a predetermined voltage (e.g., 0 V).
  • a predetermined voltage e.g., 0 V
  • the voltage measurement circuits 21, 22, and 23 may each be structured to output, as information, the detected voltages of the respective fuel cells as they are.
  • Information Ml output from the first voltage measurement circuit 21, information M2 output from the second voltage measurement circuit 22, and information M3 output from the third voltage measurement circuit 23 are transmitted to the control circuit 80, etc. and are used as needed.
  • Each of the voltage measurement circuits 21, 22, and 23 may include operational amplifiers and extract the voltages of the respective fuel cells using the operational amplifiers. In this case, the operational amplifiers are driven with the positive side power supply voltage Vc and the negative side power supply voltage Vs. It is to be noted that the voltage measurement circuits 21, 22, and 23 do not necessarily include the operational amplifiers, that is, they may have various other configurations, such as those including integrated circuits (ICs). That is, each of the voltage measurement circuits 21, 22, and 23 may have any configuration as long as it can be driven with the positive side power supply voltage Vc and the negative side power supply voltage Vs.
  • ICs integrated circuits
  • the DC-DC converters 41, 42, and 43 are the circuits that supply the positive side power supply voltages Vc and the negative side power supply voltages Vs to the voltage measurement circuits 21, 22, and 23, respectively.
  • each of the DC-DC converters 41, 42, and 43 is an insulated type DC-DC converter in which the input and output are insulated from each other.
  • First input terminals of the DC-DC converters 41, 42, and 43 are connected to the battery (secondary battery) 70 via a first power supply switchover switch 60. Second input terminals of the DC-DC converters 41, 42, and 43 are grounded.
  • Positive output terminals Tl of the DC-DC converters 41, 42, and 43 are connected, respectively, to positive power supply terminals PI of the voltage measurement circuits 21, 22, and 23 via first connection lines SI.
  • Negative output terminals T2 of the DC-DC converters 41, 42, and 43 are connected, respectively, to negative power supply terminals P2 of the voltage measurement circuits 21, 22, and 23 via second connection lines S2.
  • the direct current voltage of the battery 70 starts to be supplied to the DC-DC converters 41, 42, and 43.
  • the DC-DC converters 41, 42, and 43 each convert the direct current voltage into the positive side power supply voltage Vc and negative side power supply voltage Vs described above and then supply them to the corresponding voltage supply of the voltage measurement circuits 21, 22, and 23.
  • the battery 70 and the DC-DC converters 41, 42, and 43 serve as "power supply portion" that supplies the positive side power supply voltages Vc and the negative side power supply voltages Vs to the voltage measurement circuits 21, 22, and 23.
  • the voltage measurement circuits 21, 22, and 23 can be powered by the fuel cell stack FCS, as well as by the battery 70 and the DC-DC converters 41, 42, and 43. More specifically, cathode terminals Ql of the fuel cell blocks Bl, B2, and B3, which include the fuel cells FC1 to FC4, the fuel cells FC5 to FC8, and the fuel cells FC9 to FC12, respectively, are connected to the positive power supply terminals PI of the voltage measurement circuits 21, 22, and 23, respectively, via third connection lines S3, while anode terminals Q2 of the fuel cell blocks Bl, B2, and B3, which include the fuel cells FC1 to FC4, the fuel cells FC5 to FC8, and the fuel cells FC9 to FC12, respectively, are connected to the negative power supply terminals P2 of the voltage measurement circuits 21, 22, and 23, respectively, via fourth connection lines S4.
  • connection lines S3 and the fourth connection lines S4 serve as "connection lines” through which the output of the fuel cell stack FCS is supplied, as the positive side power supply voltages Vc and the negative side power supply voltages Vs, to the voltage measurement circuits 21, 22, and 23. Further, it is to be noted that the third connection lines S3 may be regarded as “positive connection lines” and the fourth connection lines S4 may be regarded as "negative connection lines”.
  • a diode D3 is provided voltage supply each of the third connection lines S3 to prevent backflows (i.e., the flows from the positive power supply terminal PI side to the cathode terminal Ql side), and a diode D4 is provided on each of the fourth connection lines S4 to prevent backflows (i.e., the flows from the anode terminal Q2 side to the negative power supply terminal P2 side).
  • a diode Dl is provided on each of the first connection lines Si, via which the voltage measurement circuits 21, 22, and 23 are connected, respectively, to the DC-DC converters 41, 42, and 43, to prevent backflows (i.e., the flows from the positive power supply terminal PI side to the positive output terminal Tl side), and a diode D2 is provided on each of the second connection lines S2, via which the voltage measurement circuits 21, 22, and 23 are connected, respectively, to the DC-DC converters 41, 42, and 43, to prevent backflows (i.e., the flows from the negative output terminal T2 side to the negative power supply terminal P2 side).
  • the first power supply switchover switch 60 is turned on and off in response to a control command SG output from the control circuit 80, thus performing switching between a state where the DC-DC converters 41, 42, and 43 are powered by the battery 70 and a state where the DC-DC converters 41, 42, and 43 are not powered by the battery 70, that is, switching between a state where the battery 70 is used to supply the positive side power supply voltages Vc and the negative side power supply voltages Vs to the voltage measurement circuits 21, 22, and 23 and a state where the battery 70 is not used to supply the positive side power supply voltages Vc and the negative side power supply voltages Vs to the voltage measurement circuits 21, 22, and 23.
  • the first power supply switchover switch 60 serves to switch the supply of the positive side power supply voltages Vc and negative side power supply voltages Vs to the voltage measurement circuits 21, 22, and 23 between the voltage supply using the battery 70 and the voltage supply using the output of the fuel cell stack FCS.
  • a metal oxide semiconductor field-effect transistor MOSFET is used as the first power supply switchover switch 60.
  • the control circuit 80 is a microcomputer having a known configuration including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and so on (not shown in the drawings).
  • the control circuit 80 receives the signals output from a voltage sensor 90 that detects the output voltage (total voltage) of the fuel cell stack FCS, while the control circuit 80 outputs the control command SG to the first power supply switchover switch 60.
  • the voltage sensor 90 in the first example embodiment is a voltage sensor of a type widely used in fuel cell systems.
  • the flowchart of FIG. 2 illustrates the switching procedure executed by the control circuit 80.
  • the control circuit 80 executes, using the CPU, the switching procedure on the computer program for this procedure, which is stored in the ROM of the control circuit 80.
  • the CPU first determines whether the fuel cell system including the fuel cell stack FCS is in the ON state (step S100).
  • step S100 If it is determined in step S100 that the fuel cell system is in the ON state, the CPU then reads an output voltage Vfs of the fuel cell stack FCS from the voltage sensor 90 (step SllO), and then determines whether the output voltage Vfs is equal to Or higher than a predetermined voltage VO (step S120).
  • the predetermined voltage VO is set to, for example, 120 V when the number of fuel cells of the fuel cell stack FCS is 300. That is, step SI 20 is executed to determine whether all the outputs of all the fuel cell blocks Bl to B3 of the fuel cell stack FCS are appropriate. If the output voltage Vfs is equal to or higher than the predetermined voltage V0, it is presumed that all the outputs of all the fuel cell blocks Bl to B3 are appropriate.
  • the "appropriate" outputs of the fuel cell blocks Bl to B3 represent voltages high enough to power the voltage measurement circuits 21, 22, and 23 corresponding to the fuel cell blocks Bl to B3, respectively. If the output voltage Vfs is lower than the predetermined voltage V0, it is determined that not all the outputs of all the fuel cell blocks Bl to B3 are appropriate.
  • step S120 If it is determined in step S120 that the output voltage Vfs is lower than the predetermined voltage V0, that is, if it is determined that not all the outputs of all the fuel cell blocks Bl to B3 are appropriate, the CPU then outputs, to the first power supply switchover switch 60, the control command SG for turning on the first power supply switchover switch 60 (e.g., a digital signal of "1") (step S130).
  • the control command SG for turning on the first power supply switchover switch 60 e.g., a digital signal of "1"
  • step S130 direct current voltages are supplied from the battery 70 to the DC-DC converters 41, 42, and 43, respectively, that is, the positive side power supply voltages Vc and the negative side power supply voltages Vs are supplied to the voltage measurement circuits 21, 22, and 23 using the battery 70.
  • step S130 the CPU returns to step S100 and repeats the processes in step S100 and the subsequent steps.
  • step SI 20 if it is determined in step SI 20 that the output voltage Vfs is equal to or higher than the predetermined voltage V0, that is, if it is determined that all the outputs of all the fuel cell blocks Bl to B3 are appropriate, the CPU then outputs, to the first power supply switchover switch 60, the control command SG for turning off the first power supply switchover switch 60 (e.g., a digital signal Of "0") (step SI 40).
  • the positive side power supply voltages Vc and the negative side power supply voltages Vs are supplied to the voltage measurement circuits 21, 22, and 23 from the fuel cell stack FCS, in place of the DC-DC converters 41, 42, and 43.
  • step S140 After executing step S140, the CPU returns to step S100 and repeats the processes in step S100 and the subsequent steps.
  • step S100 The CPU finishes the switching procedure described above if it is determined in step S100 that the fuel cell system is not in the ON state, that is, the fuel cell system is in the OFF state. It is to be noted that the control circuit 80 that executes the switching procedure described above and the first power supply switchover switch 60 serve as "control portion" in the invention.
  • the voltage monitoring apparatus 10 structured as described above, in a case where the fuel cell stack FCS is started up while the output voltage (total voltage) of the fuel cell stack FCS is not high enough to drive the voltage measurement circuits 21, 22, and 23 for the respective fuel cell blocks Bl to B3, the positive side power supply voltages Vc and the negative side power supply voltages Vs are supplied to the voltage measurement circuits 21, 22, and 23 using the battery 70, and when the total voltage of the fuel cell stack FCS thereafter becomes high enough to drive the voltage measurement circuits 21, 22, and 23 for the respective fuel cell blocks Bl to B3, the positive side power supply voltages Vc and the negative side power supply voltages Vs start to be supplied using the fuel cell stack FCS.
  • the battery 70 which is a power supply other than the fuel cell stack FCS, can be used, and on the other hand, in a case where the fuel cell stack FCS is started up while the total voltage of the fuel cell stack FCS is enough, such as during steady operation, the output of the fuel cell stack FCS can be used.
  • the battery 70 needs to be charged with the power supplied from the other power supply, such as the fuel cell stack FCS, and therefore the power loss is larger than it is when the voltage measurement circuits 21, 22, and 23 are powered using the fuel cell stack FCS.
  • the voltage measurement circuits 21, 22, and 23 are powered using the battery 70 only in a state where the total voltage of the fuel cell stack FCS is low, such as when the fuel cell stack FCS is started up at a low temperature (note that the total voltage of the fuel cell stack FCS remains low only for a short period of time, such as voltage supply to two minutes, after the fuel cell stack FCS has been started up at a low temperature), and therefore it is possible to reduce the cases where the voltage measurement circuits 21, 22, and 23 are powered by the battery 70, which may cause a relatively large power loss.
  • the voltage monitoring apparatus 10 of the first example embodiment provides an advantage that the overall power loss can be suppressed.
  • FIG. 3 schematically shows the configuration of a voltage monitoring apparatus 110 of the second example embodiment.
  • the structural elements identical to those in the first example embodiment are denoted by the same reference numerals as those in FIG. 1.
  • the differences of the voltage monitoring apparatus 110 from the voltage monitoring apparatus 10 of the first example embodiment will be described.
  • the voltage monitoring apparatus 10 of the first example embodiment is structured such that a predetermined power supply voltage (i.e., the voltage of the battery 70) is converted into the positive side power supply voltages Vc and the negative side power supply voltages Vs using the DC-DC converters 41, 42, and 43
  • the voltage monitoring apparatus 110 of the second example embodiment is structured such that the total voltage of the fuel cell stack FCS is used as the predetermined power supply voltage and it is converted into the positive side power supply voltages Vc and the negative side power supply voltages Vs using a voltage divider resistor circuit.
  • the voltage monitoring apparatus 110 of the second example embodiment has a voltage divider resistor circuit including a first voltage divider resistor circuit section RCl for the positive side power supply voltages Vc and a second voltage divider resistor circuit section RC2 for the negative side power supply voltages Vs.
  • the first voltage divider resistor circuit section RCl includes four resistors Rl, R2, R3, and R4 that are connected in series.
  • a terminal Til that is located, as viewed in FIG. 3, above the series of the resistors Rl, R2, R3, and R4 is connected to a terminal ST1, provided on voltage supply side (i.e., the first voltage measurement circuit 21 side) of the first power supply switchover switch 60.
  • the terminal Til is also connected to a first connection line SI (denoted "SI a" in FIG. 3 for distinguishing it from other first connection lines SI) that is connected to the positive power supply terminal PI of the first voltage measurement circuit 21.
  • SI denoted "SI a" in FIG. 3 for distinguishing it from other first connection lines SI
  • a terminal ST2 provided on the other side of the first power supply switchover switch 60, is connected to the cathode terminal Ql of the first fuel cell block Bl including the fuel cells FCl to FC4, the cathode terminal Ql serving as the positive output terminal of the entire fuel cell stack FCS.
  • the resistors Rl, R2, R3, and R4 are arranged in this order from the upper side toward the lower side of FIG. 3, and they will hereinafter be referred to as "the first resistor Rl", “the second resistor R2", “the third resistor R3", and “the fourth resistor R4", respectively.
  • the connection line between the first resistor Rl and the second resistor R2 is connected to the first connection line SI (denoted “Sib” in FIG. 3) that is connected to the positive power supply terminal PI of the second voltage measurement circuit 22.
  • the connection line between the second resistor R2 and the third resistor R3 is connected to the first connection line SI (denoted “Sic” in FIG. 3) that is connected to the positive power supply terminal PI of the third voltage measurement circuit 23.
  • the first voltage divider resistor circuit section RC1 can properly function if it has at least three resistors.
  • the four resistors Rl to R4 are provided as described above, and they are used to divide the voltage into for voltages, and the three voltages at the higher voltage side, that is, at the positive side, are supplied to the voltage measurement circuits 21, 22, and 23, respectively.
  • the second voltage divider resistor circuit section RC2 includes four resistors R5, R6, R7, and R8 that are connected in series.
  • a terminal T21 that is located, as viewed in FIG. 3, above the series of the resistors R5, R6, R7, and R8 is connected to the positive output terminal of the fuel cell stack FCS, and a terminal T22 shown at the lower side of FIG. 3 is connected to the negative output terminal of the fuel cell stack FCS.
  • a second power supply switchover switch 160 is provided immediately before the terminal T22 shown at the lower side of FIG. 3.
  • the second power supply switchover switch 160 is connected to the control circuit 80, as is the first power supply switchover switch 60.
  • the resistors R5, R6, R7, and R8 are arranged in this order from the upper side toward the lower side of FIG. 3, and they will hereinafter be referred to as "the fifth resistor R5", “the sixth resistor R6", “the seventh resistor R7”, and “the eighth resistor R8", respectively.
  • the connection line between the sixth resistor R6 and the seventh resistor R7 is connected to the second connection line S2 (denoted “S2a" in FIG. 3) that is connected to the negative power supply terminal P2 of the first voltage measurement circuit 21.
  • connection line between the seventh resistor R7 and the eighth resistor R8 is connected to the second connection line S2 (denoted “S2b” in FIG 3) that is connected to the negative power supply terminal P2 of the second voltage measurement circuit 22.
  • connection line between the eighth resistor R8 and the terminal T22 is connected to the second connection line S2 (denoted "S2c” in FIG. 3) that is connected to the negative power supply terminal P2 of the third voltage measurement circuit 23.
  • the voltage is divided into four voltages using the four resistors R5 to R8, as in the first voltage divider resistor circuit section RC1, and the three voltages at the lower voltage side, that is, at the negative side, are supplied to the voltage measurement circuits 21, 22, and 23, respectively.
  • a current 10 flowing through the entirety of the first voltage divider resistor circuit section RC1 is set much larger than a current II flowing through the first connection line Sla for the first voltage measurement circuit 21, a current 12 flowing through the first connection line Sib for the second voltage measurement circuit 22, and a current 13 flowing through the first connection line Sic for the third voltage measurement circuit 23, and the current flowing through the second voltage divider resistor circuit section RC2 (not shown in the drawings) is set much larger than the currents flowing through the respective second connection lines S2a, S2b, and S2c (not shown in the drawings).
  • a typical option for accomplishing such output voltage stabilization is to set the currents II, 12, and 13 extremely small (i.e., set the input resistances extremely high), however it is not easy to set the currents II, 12, and 13 small because the first connection lines Sla, Sib, and Sic are all power lines.
  • the voltage monitoring apparatus 110 is configured such that the current 10 flowing through the entirety of the voltage divider resistor circuit is extremely large.
  • the current 10 flowing through the entirety of the voltage divider resistor circuit may be set extremely large by making the resistances of the resistors Rl to R8 different from each other.
  • the voltage divider resistor circuit is used only for a very short period of time, as is the battery 70 in the first example embodiment, and therefore setting the current 10 large does not lead to any problem in terms of the power loss.
  • the control circuit 80 executes a switching procedure that is basically the same as that executed in the first example embodiment (refer to FIG. 2).
  • the first power supply switchover switch 60 and the second power supply switchover switch 160 are both turned on in step S130, and then the first power supply switchover switch 60 and the second power supply switchover switch 160 are both turned off in step S140.
  • the supply of the positive side power supply voltages Vc and negative side power supply voltages Vs to the voltage measurement circuits 21, 22, and 23 is switched between the voltage supply using the total voltage of the fuel cell stack FCS and the voltage supply using the fuel cells FC1 to FC4 belonging to the first fuel cell block Bl corresponding to the first voltage measurement circuit 21, the fuel cells FC5 to FC8 belonging to the second fuel cell block B2 corresponding to the second voltage measurement circuit 22, and the fuel cells FC9 to FC12 belonging to the third fuel cell block B3 corresponding to the third voltage measurement circuit 23.
  • the total voltage of the fuel cell stack FCS does not significantly decrease (although the total voltage of the fuel cell stack FCS may become lower than the predetermined voltage V0 used in step S110 in FIG 2, it is still as high as several tens volts, for example). Therefore, even in a state where the total voltage of the fuel cell stack FCS is lower than the predetermined voltage V0, it is possible to supply the positive side power supply voltages Vc and the negative side power supply voltages Vs using the total voltage of the fuel cell stack FCS.
  • the voltage monitoring apparatus 110 provides an advantage that no battery is required and thus the power loss can be suppressed. Further, because the voltage monitoring apparatus 110 is structured to power, as needed, the voltage measurement circuits 21, 22, and 23 using the voltage divider resistor circuit, it also provides an advantage that the unit can be made compact in size. That is, a voltage converter is normally large in size since it includes a transformer, however a voltage divider resistor circuit, on the other hand, is constituted of resistors, and therefore the unit including a voltage divider resistor circuit is small in size.
  • the voltage monitoring apparatus 110 of the second example embodiment is configured such that the voltage is divided into the four voltages using the four resistors Rl to R4, the number of which is one more than the number of the fuel cell blocks of the fuel cell stack FCS, and the three voltages at the higher voltage side are supplied to the voltage measurement circuits 21, 22, and 23, respectively (the voltage is divided into the four voltages using the four resistors R5 to R8, and the three voltages at the lower voltage side, that is, the negative side are supplied to the voltage measurement circuits 21, 22, and 23, respectively).
  • This configuration is employed because the voltage subjected to voltage division needs to have some margins as mentioned earlier.
  • a voltage monitoring apparatus of the third example embodiment is configured such the voltage is divided into three voltages using three resistors Rl to R3, the number of which is the same as the number of the fuel cell blocks of the fuel cell stack FCS (i.e., the voltage divider resistor circuit has no function of providing the margins stated above), although other structures are substantially the same as those of the second example embodiment.
  • the third example embodiment is different from the second example embodiment in that the voltage measurement circuits 21, 22, and 23 each include a converter.
  • the positive side power supply voltages supplied to the positive power supply terminals PI of the voltage measurement circuits 21, 22, and 23, respectively, are boosted, using the respective converters, to have larger differences from the respective negative side power supply voltages, while the negative side power supply voltages supplied to the negative power supply terminals P2 of the voltage measurement circuits 21, 22, and 23, respectively, are reduced, using the respective converters, to have larger differences from the respective positive side power supply voltages, whereby the difference between the positive side power supply voltage and the negative side power supply voltage to be supplied to the main circuit of each of the voltage measurement circuits 21, 22, and 23 is increased (note that the phrase "voltage is reduced", and the like, in this specification are intended to encompass, for example, reducing 0 V down to a given negative voltage and reducing a given negative voltage down to a negative voltage having a larger absolute value).
  • the voltage monitoring apparatus of the third example embodiment which is structured as described above, operates in basically the same manner as the voltage monitoring apparatus 110 of the second example embodiment. For this reason, the voltage monitoring apparatus of the third example embodiment provides basically the same advantage as the voltage monitoring apparatus 110 of the second example embodiment.
  • the positive side power supply voltages and the negative side power supply voltages can be supplied, as needed, using a voltage divider resistor circuit, and four resistors Rl to R4, the number of which is one more than the number of the fuel cell blocks of the fuel cell stack FCS, are used so that the voltage subjected to voltage division has some margins, as mentioned earlier.
  • FIG 4 schematically shows the configuration of a voltage monitoring apparatus 210 of the fourth example embodiment.
  • the voltage monitoring apparatus 210 of the fourth example embodiment is different from the voltage monitoring apparatus 110 of the second example embodiment (refer to FIG 3) in that the predetermined power supply voltage supplied to the voltage divider resistor circuit is the voltage obtained by boosting the output voltage of a battery using a DC-DC converter, rather than the total voltage of the fuel cell stack FCS. More specifically, referring to FIG.
  • a battery 270 and a DC-DC converter 280 connected to the battery 270 are provided, and the terminal ST2, provided on the other side (i.e., the side opposite to the terminal ST1) of the first power supply switchover switch 60, is connected to the positive output terminal of the DC-DC converter 280 while a connection portion T23 between the eighth resistor R8 and the second connection line S2 is connected to the negative output terminal of the DC-DC converter 280.
  • the connection line for connecting the eighth resistor R8 to the negative output terminal of the fuel cell stack FCS which is provided in the second example embodiment, is not required in the fourth example embodiment.
  • the DC-DC converter 280 converts the voltage supplied from the battery 270 into a positive side power supply voltage and a negative side power supply voltage, the difference between which is relatively large.
  • the DC-DC converter 280 is a converter that achieves a voltage-boosting rate high enough to boost the output voltage of the battery 270, for example, from 12 V up to 100 V. Thus, sufficient power supply voltages can be supplied to all the voltage measurement circuits
  • the voltage monitoring apparatus 210 of the fourth example embodiment operates in the same manner as the voltage monitoring apparatus 110 of the second example embodiment. Therefore, the voltage monitoring apparatus 210 of the fourth example embodiment provides the same advantage as the voltage monitoring apparatus 110 of the second example embodiment.
  • a single DC-DC converter i.e., the DC-DC converter 280
  • a single voltage divider resistor circuit including the first voltage divider resistor circuit section RC1 and the second voltage divider resistor circuit section RC2
  • the voltage monitoring apparatus 210 may be configured such that the voltage measurement circuits are divided into a plurality of voltage measurement circuit groups, and a single DC-DC converter and a single voltage divider resistor circuit (including the first voltage divider resistor circuit section RC1 and the second voltage divider resistor circuit section RC2) are used to assist the powering of each voltage measurement circuit group.
  • a modified version of the fourth example embodiment may be obtained by combining the structure of the fourth example embodiment with the structure of the second example embodiment in which the total voltage of the fuel cell stack FCS is used to power the voltage measurement circuits 21, 22, and 23.
  • FIG. 5 schematically shows the configuration of a voltage monitoring apparatus 410 as such a modified version of the fourth example embodiment.
  • the configuration of the voltage monitoring apparatus 410 of the modified version is basically the same as that of the voltage monitoring apparatus 210 of the fourth example embodiment, it further has the following structural features. It is to be noted that, in FIG 5, the same structural elements as those in the fourth example embodiment are denoted by the same reference numerals as those in FIG. 4.
  • a direction switchover switch 62 that is capable of switching its connection direction between two directions is provided midway on the connection line between the terminal ST2 located on the other side (i.e., the side opposite to the first voltage measurement circuit 21) of the first power supply switchover switch 60, and the positive output terminal of the DC-DC converter 280.
  • the direction switchover switch 62 has another port that is connected to the cathode terminal Ql of the first fuel cell block Bl including the fuel cells FC1 to FC4, the cathode terminal Ql serving .as the positive output terminal of the entire fuel cell stack FCS.
  • the direction switchover switch 62 is used to perform switching between a first state where the terminal ST2 and the DC-DC converter 280 are electrically connected to each other and a second state where the terminal ST2 and the cathode terminal Ql of the first fuel cell block Bl, which serves as the positive output terminal of the entire fuel cell stack FCS, are electrically connected to each other.
  • the control circuit 80 controls the direction switchover switch 62.
  • the control circuit 80 executes basically the same switching procedure as that executed by the control circuit 80 in the second example embodiment, and it further executes a procedure for controlling the direction switchover switch 62 based on the total voltage of the fuel cell stack FCS.
  • the direction switchover switch 62 is placed in the first state when the total voltage of the fuel cell stack FCS has fallen to an extremely low level (e.g., ten and several volts, that is, a voltage lower than "several tens volts" stated above, by way of example, in the descriptions on the second example embodiment), and the direction switch over switch 62 is placed in the second state when the total voltage of the fuel cell stack FCS is not extremely low.
  • an extremely low level e.g., ten and several volts, that is, a voltage lower than "several tens volts" stated above, by way of example, in the descriptions on the second example embodiment
  • the voltage monitoring apparatus 410 as the modified version of the fourth example embodiment provides basically the same advantage as the second and fourth example embodiments.
  • the total voltage of the fuel cell stack FCS is used on purpose to accelerate the warming up of the fuel cell stack FCS when it has been started up at a low temperature, and the battery can be used when the total voltage of the fuel cell stack FCS has fallen to an extremely low level, thus achieving a good controllability.
  • a voltage divider resistor circuit is used to boost the positive side power supply voltages and reduce the negative side power supply voltages, so that the differences therebetween become large.
  • FIG. 6 schematically shows the configuration of a voltage monitoring apparatus 310 of the fifth example embodiment.
  • the voltage monitoring apparatus 310 of the fifth example embodiment is different from the voltage monitoring apparatus 110 of the second example embodiment (refer to FIG. 3) in the following points (1) to (9).
  • the third connection line S3 provided near the second voltage measurement circuit 22 is connected to the cathode terminal Ql of the second fuel cell block B2 including the fuel cells FC5 to FC8 in the second example embodiment
  • the third connection line S3 provided near the second voltage measurement circuit 22 is connected to a given point of the power path in the first fuel cell block Bl including the four fuel cells FCl to FC4 that are connected in series.
  • the "given point" is the cathode terminal of the fuel cell FC3, which is the second fuel cell from the negative side among the four fuel cells FCl to FC4.
  • the point to which the third connection line S3 provided near the second voltage measurement circuit 22 is connected may be any of the cathode terminals of the fuel cells FC1 to FC4, and the third connection line S3 provided near the second voltage measurement circuit 22 may be connected to a cathode terminal of any fuel cell, as long as a voltage on the positive side of the second fuel cell block B2 can be extracted through the third connection line S3.
  • the term "a voltage on the positive side of the second fuel cell block B2" signifies a voltage at a position closer to the positive side in the fuel cell stack than the second fuel cell block B2 is.
  • the third connection line S3 provided near the third voltage measurement circuit 23 is connected to the cathode terminal Ql of the third fuel cell block B3 including the fuel cells FC9 to FC12 in the second example embodiment, in the voltage monitoring apparatus 310 of the fifth example embodiment, the third connection line S3 provided near the third voltage measurement circuit 23 is connected to a given point of the power path in the second fuel cell block B2 including the four fuel cells FC5 to FC8 that are connected in series.
  • the "given point" is the cathode terminal of the fuel cell FC7, which is the second fuel cell from the negative side among the four fuel cells FC5 to FC8.
  • the point to which the third connection line S3 provided near the second voltage measurement circuit 23 is connected may be any of the cathode terminals of the fuel cells FC5 to FC8, and the third connection line S3 provided near the third voltage measurement circuit 23 may be connected to a cathode terminal of any fuel cell, as long as a voltage on the positive side of the second fuel cell block B3 can be extracted through the third connection line S3
  • the fourth connection line S4 provided near the first voltage measurement circuit 21 is connected to the anode terminal Q2 of the first fuel cell block Bl including the fuel cells FC1 to FC4 in the second example embodiment, in the voltage monitoring apparatus 310 of the fifth example embodiment, the fourth connection line S4 provided near the first voltage measurement circuit 21 is connected to a given point of the power path in the second fuel cell block B2 including the four fuel cells FC5 to FC8 that are connected in series.
  • the "given point" is the cathode terminal of the fuel cell FC7, which is the third fuel cell from the positive side among the four fuel cells FC5 to FC8.
  • the point to which the fourth connection line S4 provided near the first voltage measurement circuit 21 is connected may be any of the cathode terminals of the fuel cells FC5 to FC8, and the fourth connection line S4 provided near the first voltage measurement circuit 21 may be connected to a cathode terminal of any fuel cell, as long as a voltage on the negative side of the first fuel cell block Bl can be extracted through the fourth connection line S4.
  • the fourth connection line S4 provided near the second voltage measurement circuit 22 is connected to the anode terminal Q2 of the second fuel cell block B2 including the fuel cells FC5 to FC8 in the second example embodiment
  • the fourth connection line S4 provided near the second voltage measurement circuit 22 is connected to a given point of the power path in the third fuel cell block B3 including the four fuel cells FC9 to FC12 that are connected in series.
  • the "given point" is the cathode terminal of the fuel cell FC11, which is the third fuel cell from the positive side among the four fuel cells FC9 to FC12.
  • the point to which the fourth connection line S4 provided near the second voltage measurement circuit 22 is connected may be any of the cathode terminals of the fuel cells FC9 to FC12, and the fourth connection line S4 provided near the second voltage measurement circuit 22 may be connected to a cathode terminal of any fuel cell as long as a voltage on the negative side of the second fuel cell block B2 can be extracted through the fourth connection line S4.
  • the voltage monitoring apparatus 310 of the fifth example embodiment includes a first DC-DC converter 321, and the positive terminal Til is connected to the positive output terminal of the first DC-DC converter 321. It is to be noted that the negative output terminal of the first DC-DC converter 321 is connected to the positive output terminal of the fuel cell stack FCS.
  • the voltage monitoring apparatus 310 of the fifth example embodiment includes a second DC-DC converter 322, and the negative output terminal of the second DC-DC converter 322 is connected to the connection portion via which the second connection line S2c connected to the negative power supply terminal P2 of the third voltage measurement circuit 23 is connected to the second voltage divider resistor circuit section RC2. It is to be noted that a positive output terminal T22 of the second DC-DC converter 322 is connected to the negative output terminal of the fuel cell stack FCS. Further, it is to be noted that the first DC-DC converter 321 and the second DC-DC converter 322 are both connected to a battery 370.
  • the voltage monitoring apparatus 310 of the fifth example embodiment includes a first power supply switchover switch 361 provided between the first voltage divider resistor circuit section RCl and the connection point Til shown in FIG. 6 and a second power supply switchover switch 362 provided between the second voltage divider resistor circuit section RC2 and the second connection line S2c.
  • the first power supply switchover switch 361 and the second power supply switchover switch 362 are turned on and off in response to the control commands output from the control circuit 80.
  • the control circuit 80 in the fifth example embodiment is basically the same as the control circuit 80 in the first example embodiment.
  • control circuit 80 executes a control procedure in which the battery 370, which is a power supply other than the fuel cell stack FCS, is used in a state where not all the outputs of all the fuel cell blocks Bl to B3 of the fuel cell stack FCS are appropriate, such as when the fuel cell stack FCS is started up at a lower temperature, while the output of the fuel cell stack FCS is used in a state where all the outputs of all the fuel cell blocks Bl to B3 are appropriate, such as during steady operation.
  • the battery 370 which is a power supply other than the fuel cell stack FCS
  • the positive side power supply voltage Vc that is output from the first DC-DC converter 321 and thus has a relatively large difference from the negative side power supply voltage Vs is supplied to the positive power supply terminal PI of the first voltage measurement circuit 21, while the negative side power supply voltage Vs that is output from an intermediate point of the power path in the second fuel cell block B2 including the fuel cells FC5 to FC8 and thus has a relatively large difference from the positive side power supply voltage Vc is supplied to the negative power supply terminal P2 of the first voltage measurement circuit 21. Further, the positive side power supply voltage Vc that is output from an intermediate point of the power path in the first fuel cell block Bl including the fuel cells
  • FC1 to FC4 and thus has a relatively large difference from the negative side power supply voltage Vs is supplied to the positive power supply terminal PI of the second voltage measurement circuit 22, while the negative side power supply voltage Vs that is output from an intermediate point of the power path in the third fuel cell block B3 including the fuel cells FC9 to FC12 and thus has a relatively large difference from the positive side power supply voltage Vc is supplied to the negative power supply terminal P2 of the second voltage measurement circuit 22. Further, the positive side power supply voltage
  • Vc that is output from an intermediate point of the power path in the second fuel cell block B2 including the fuel cells FC5 to FC8 and thus has a relatively large difference from the negative side power supply voltage Vs is supplied to the positive power supply terminal PI of the third voltage measurement circuit 23, while the negative side power supply voltage Vs that is output from the second DC-DC converter 322 and thus has a relatively large difference from the positive side power supply voltage Vc is supplied to the negative power supply terminal P2 of the third voltage measurement circuit 23.
  • the voltage monitoring apparatus 310 of the fifth example embodiment operates in basically the same manner as the voltage monitoring apparatus 110 of the second example embodiment. Therefore, the voltage monitoring apparatus 310 of the fifth example embodiment provides the same advantage as the voltage monitoring apparatus 110 of the second example embodiment.
  • the fuel cell stack FCS in the fifth example embodiment includes the three fuel cell blocks Bl to B3, in a case where it includes, for example, four fuel cell blocks, the positive power supply terminal of the second voltage measurement circuit corresponding to the second fuel cell block from the positive side is connected to the fuel cell block present on the positive side of the second fuel cell block, and the positive power supply terminal of the third voltage measurement circuit corresponding to the third fuel cell block from the positive side is connected to the fuel cell block present on the positive side of the third fuel cell block, as is the positive power supply terminal of the second voltage measurement circuit 22 of the voltage monitoring apparatus 310, and, on the other hand, the negative power supply terminal of the second voltage measurement circuit corresponding to the second fuel cell block from the positive side is connected to the fuel cell block present on the negative side of the second fuel cell block, and the negative power supply terminal of the third voltage measurement circuit corresponding to the third fuel cell block from the positive side is connected to the fuel cell block present on the negative side of the third fuel cell block.
  • a temperature sensor such as a temperature sensor for detecting the temperature of a reaction portion, is provided at the fuel cell stack FCS, and when the value detected by the temperature sensor is smaller (lower) than a predetermined temperature, it is determined that not all the outputs of all the fuel cell blocks Bl to B3 of the fuel cell stack FCS are appropriate.
  • This structure also provides basically the same advantage as the foregoing example embodiments.
  • the switching of power supply for the respective voltage measurement circuits is performed based on whether all the outputs of all the fuel cell blocks Bl to B3 of the fuel cell stack FCS are appropriate in the foregoing example embodiments, the switching may be performed in various other manners.
  • the condition for performing the switching may be any condition as long as it accomplishes switching timing that improves the power efficiency of the entire fuel cell system.
  • each voltage converter is not limited to any specific type. That is, for example, an AC-DC converter may be used. In this case, an alternating current voltage is externally supplied.
  • circuit configurations of voltage monitoring apparatuses according to the invention are not limited to any of those in the foregoing examples and modified versions thereof. That is, for example, the voltage monitoring apparatuses of the foregoing example embodiments and modified versions thereof may each include, as an alternative, an equivalent circuit that has the same functions or basically the same functions. For example, transistors may be used in place of the diodes Dl to D4 (refer to FIG 1).
  • the invention may be applied to fuel cells that are different in type from those in the foregoing example embodiments. That is, the invention may be applied also to fuel cells of various other types, including direct methanol fuel cells and phosphoric acid fuel cells.

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Abstract

La présente invention a trait à un appareil de surveillance de tension destiné à un bloc de piles à combustible incluant de multiples piles à combustible branchées en série et divisées en deux groupes ou plus, lequel appareil de surveillance de tension inclut : des circuits de détection prévus pour les groupes respectifs et excités chacun au moyen de tensions de bloc d'alimentation du côté positif et négatif afin de détecter les tensions des piles à combustible du groupe correspondant et de fournir en sortie des informations en fonction des tensions détectées; des trajectoires de connexion par l'intermédiaire desquelles les circuits de détection sont connectés, respectivement, à des combinaisons et reçoivent les tensions de bloc d'alimentation du côté positif et négatif provenant des combinaisons respectives; une partie de bloc d'alimentation qui fournit les tensions de bloc d'alimentation du côté positif et négatif aux circuits de détection; et une partie de commande qui commute l'alimentation de la tension vers les circuits de détection entre l'alimentation de la tension par l'intermédiaire des trajectoires de connexion et l'alimentation de la tension utilisant la partie de bloc d'alimentation, conformément à une condition prédéterminée.
PCT/IB2011/001183 2010-06-02 2011-05-31 Appareil de surveillance de tension et procédé de surveillance de tension WO2011151700A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
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CN103633700A (zh) * 2013-12-03 2014-03-12 国家电网公司 一种并联蓄电池内阻在线检测的直流系统
WO2014182332A1 (fr) * 2013-05-09 2014-11-13 Parker-Hannifin Corporation Système de commande de puissance d'une pile à combustible pour le domaine aérospatial
CN109324293A (zh) * 2018-10-09 2019-02-12 苏州华清京昆新能源科技有限公司 一种用于电堆测试的多电堆结构及多电堆测试装置
CN109698372A (zh) * 2017-10-20 2019-04-30 辉能科技股份有限公司 复合式电池芯

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KR101701604B1 (ko) * 2015-04-14 2017-02-02 현대제철 주식회사 분산형 연료전지 컨트롤러를 갖는 통합 관리 시스템 및 그 제어 방법
CN111077467A (zh) * 2019-12-06 2020-04-28 清华大学 一种阻抗测量方法和系统

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WO2014182332A1 (fr) * 2013-05-09 2014-11-13 Parker-Hannifin Corporation Système de commande de puissance d'une pile à combustible pour le domaine aérospatial
CN103605000A (zh) * 2013-12-03 2014-02-26 国家电网公司 一种并联蓄电池内阻在线检测方法
CN103633700A (zh) * 2013-12-03 2014-03-12 国家电网公司 一种并联蓄电池内阻在线检测的直流系统
CN109698372A (zh) * 2017-10-20 2019-04-30 辉能科技股份有限公司 复合式电池芯
CN109324293A (zh) * 2018-10-09 2019-02-12 苏州华清京昆新能源科技有限公司 一种用于电堆测试的多电堆结构及多电堆测试装置

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