WO2005053061A2 - Electric storage augmentation of fuel cell system transient response - Google Patents

Electric storage augmentation of fuel cell system transient response Download PDF

Info

Publication number
WO2005053061A2
WO2005053061A2 PCT/US2004/038719 US2004038719W WO2005053061A2 WO 2005053061 A2 WO2005053061 A2 WO 2005053061A2 US 2004038719 W US2004038719 W US 2004038719W WO 2005053061 A2 WO2005053061 A2 WO 2005053061A2
Authority
WO
WIPO (PCT)
Prior art keywords
fuel cell
voltage
cell stack
storage device
electric
Prior art date
Application number
PCT/US2004/038719
Other languages
French (fr)
Other versions
WO2005053061A3 (en
Inventor
David G. Converse
Steven J. Fredette
Original Assignee
Utc Fuel Cells, Llc
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 Utc Fuel Cells, Llc filed Critical Utc Fuel Cells, Llc
Priority to EP04811433.4A priority Critical patent/EP1692736B1/en
Priority to JP2006541375A priority patent/JP2007511891A/en
Publication of WO2005053061A2 publication Critical patent/WO2005053061A2/en
Publication of WO2005053061A3 publication Critical patent/WO2005053061A3/en

Links

Classifications

    • 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
    • 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
    • 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
    • H01M8/04865—Voltage
    • H01M8/0488—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
    • H01M8/04865—Voltage
    • H01M8/04888—Voltage 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
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
    • H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
    • 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
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
    • H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
    • H01M8/0618—Reforming processes, e.g. autothermal, partial oxidation or steam reforming
    • 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

  • This invention relates to a fuel cell power plant having batteries or a bank of super capacitors connected electrically in parallel with the fuel cell stack, thereby to provide energy for increased load transients and to absorb energy during decrease load transients.
  • the excess hydrogen may pass into a downstream burner of some sort; the amount of hydrogen fed to the burner under a reduced-load transient may be several times the amount of hydrogen that the burner would normally have to handle, hi order to be able to consume the excess hydrogen, without causing equipment damage, the volume and burning capacity must be increased, which increases the overall volume and cost of the fuel cell power plant. If excess hydrogen is simply exhausted, it must be done so in a safe manner, such as by diluting the hydrogen to less than one percent; this may require increased ventilation capabilities in the entire fuel processing system. Tighter controls on the fuel control response rate may mitigate the problem of excess hydrogen, but it would never eliminate the problem entirely, and may add significant cost to a fuel cell system.
  • U.S. Patent 6,572,993 The problem of excess fuel resulting from a sudden decrease in load is referred to in U.S. Patent 6,572,993.
  • the system therein operates a storage device, such as a battery pack, a plurality of capacitors or a plurality of supercapacitors, at a nearly uniform level which is a predetermined percentage of the maximum charge level, such as 80%.
  • the energy storage device absorbs excess energy generated by the fuel cell until the amount of fuel entering the anode is lowered to a level not to require the energy storage device to be necessary. At that time, the energy storage device dissipates the excess energy back to its original predetermined level. When the load returns to its previous, normal level, the energy storage device provides excess energy to maintain a desired power output level.
  • the storage level of the electric power and the energy storage device can be returned to its normal level.
  • the foregoing patent therefore, has a system in which steady state conditions are paramount, and transient dips in the load are accommodated by the manner in which the energy storage device is controlled to absorb excess energy, and to thereafter dissipate it, and at the end of the transient provides excess energy and is thereafter returned to its original predetermined level. If capacitors or supercapacitors are used as the electric storage device, since charge is equal to the voltage times the capacitance, and the charge is always set to a specific fraction, such as 80% of maximum charge, the system of said patent is always set to a fixed, certain, specific predetermined voltage, regardless of anything else.
  • a fuel cell power plant which can readily handle abrupt increases and decreases in load; increased capability of the fuel cell stack to handle abrupt decreases in load, without weakening the fuel cell structure; provision of reformers for converting hydrocarbon fuel to hydrogen for use as a fuel cell fuel which may utilize slowly responding sensors and valves; cost effective production and utilization of hydrogen in a fuel cell stack; and an improved apparatus for converting hydrocarbon fuel to electricity by means of a reformer and a fuel cell stack.
  • the invention is predicated on the realization that adjustments, not only in the amount of hydrogen required but also the power conditioning required to serve a widely varying load need not be made instantly, but may instead be instantly accommodated electrically, at the fuel cell output, provided suitable apparatus and operating methodology are employed.
  • the electrical output of a fuel cell power plant is controlled, either through actively controlled switching, with voltage conversion, or directly and passively, by an electrical storage bank, such as a bank of supercapacitors or batteries.
  • the bank of supercapacitors or batteries is connected between the fuel cell stack and the output power conditioning system that feeds the load.
  • an electrical storage bank is directly connected across the electrical output of a fuel cell stack, the voltage of the electrical storage device being allowed to follow completely, at all times, the voltage output of the fuel cell stack, without any intervening controls.
  • the electric storage device thereby automatically provides or receives charge as necessary in order to maintain the voltage of the electric storage device substantially identical to the voltage of the fuel cell stack, with only a very slight lag, which is inconsequential.
  • the voltage of an electric storage device such as a bank of supercapacitors or batteries, is isolated from the voltage of a fuel cell stack by means of a regenerative DC/DC converter.
  • the production and/or application of hydrogen to the fuel cell stack can be regulated in a fashion which is much slower than the electrical load transients, without increased cost, endangering apparatus, or polluting the atmosphere, and the power conversion apparatus feeding a grid or other load can operate in a small range, with fewer constraints, and with more efficiency at lower cost.
  • Fig. 1 is a simplified block diagram of a fuel cell power plant receiving fuel converted from hydrocarbon fuels by a reformer.
  • Fig. 2 is a simplified schematic block diagram of a variant of the system illustrated in Fig. 1 which includes a DC/DC converter.
  • Fig. 3 is a simplified schematic diagram of a variation of the configuration of Fig. 2, in which fuel for the fuel cell stack is derived from a source of hydrogen, such as a tank of hydrogen.
  • Fig. 4 is a partial, simplified schematic diagram of the apparatus of Fig. 2, illustrating that the energy storage device may be a battery.
  • a fuel cell power plant 6 includes a fuel cell stack 7 having electric output lines 8, 9 with an energy storage device, such as a supercapacitor bank 10, connected directly in parallel with the fuel cell stack 7 between the output lines 8, 9, in accordance with the invention, hi the embodiment herein, the fuel cell stack 7 receives hydrogen-containing fuel in a conduit 11 from a reformer 13 that converts hydrocarbon fuel from a source 14, which may, for example, be a catalytic partial oxidizer reformer system such as those disclosed in copending U.S. patent application Serial No. 10/369,359, filed February 18, 2003, or any other reformer suitable to provide innocuous hydrogen-rich fuel to a fuel cell stack.
  • the power on the output lines 8, 9 is controlled for its intended use by a conventional power conditioning system 15, which applies the power to a load 16 which may be a grid, an electric vehicle motor, or any other load.
  • a load 16 which may be a grid, an electric vehicle motor, or any other load.
  • the term Aload® may mean the load 16, or it may mean the power conditioning system 15 and the load 16.
  • the controller 19 With a supercapacitor bank 10 in parallel with the fuel cell stack 7, when the load 16 decreases, the controller 19 will cause less fuel to enter the fuel supply 14. There is, however, a surplus of hydrogen in the fuel cell stack and fuel supply system.
  • the voltage on power output lines 8 and 9 increases. This causes the voltage in the supercapacitors to increase and they increase in charge.
  • the increase in charge to the supercapacitors consumes the excess power from the surplus hydrogen, which mitigates the duty on the fuel cell stack exhaust system ventilation or burner (not shown).
  • the controller 19 will cause more fuel to enter the fuel cell stack by opening the fuel inlet valve in a conventional fashion, and will cause more hydrocarbon fuel to enter the reformer by opening the inlet valve thereof, along with other adjustments.
  • the fuel cell stack will not be performing adequately to handle the load. With increased current level provided by the fuel cell stack, the average cell voltage will drop, dropping the voltage of the supercapacitor bank 10, causing charge to flow out of the supercapacitor bank, thereby supplying current to the power conditioning system 15.
  • the supercapacitor bank 10 is passively controlled, automatically, by being connected directly in parallel with the electric output of the fuel cell stack 7.
  • current flows from the supercapacitor bank 10 into the power conditioning system 15 to satisfy the power needs of the load 16 in response only to the voltage of the fuel cell stack electric output on lines 8, 9.
  • the controller 19 will eventually ramp up the amount of hydrogen produced by the reformer 13 and the amount of hydrogen-rich fuel admitted from the conduit 11 into the anodes of the fuel cell stack 7.
  • the supercapacitor bank 10, in accordance with the invention will simply continue to track the voltage of the fuel cell stack output on the lines 8, 9, thereby being continuously able to respond to any variations in the load, at any stage of transients or restoration of fuel equity with respect to load.
  • the supercapacitor bank 10 is passive, that is, it simply receives or delivers electric charge in dependence on the voltage on the lines 8, 9 being greater or lesser than the voltage in the supercapacitor bank.
  • the supercapacitor bank follows the voltage of the fuel cell stack at all times, it will always, except during actual transients, be at the voltage of the fuel cell stack, and therefore be ready to respond to either a higher voltage by receiving charge or a lower voltage by delivering charge.
  • the supercapacitor bank charge and discharge functions can be augmented with a conventional regenerative DC/DC converter 22, shown in Fig. 2.
  • the DC/DC converter will be most advantageous in circumstances where the transients may be extremely rapid and large, so that the voltage of the supercapacitor bank may not be high enough to drive the increase in load, and in similar situations where the voltage transitions to much lower voltages will be so great that the supercapacitor bank will not accept the charge unless it is raised to a higher voltage.
  • Use of the converter 22 allows for a greater removal of energy (i.e., a deeper discharge).
  • the supercapacitor bank 10 may operate at voltages which are, for instance, substantially different from the voltage of the fuel cell stack on the lines 8, 9.
  • the supercapacitor bank 10 may be operated in a range of voltages that approach several hundred volts, while the fuel cell stack may operate at voltages ranging from around 250 volts dc to around 450 volts dc, in a normal operation.
  • the DC/DC converter can not only convert the voltage to some multiple or fraction of the fuel cell stack voltage, but can also buck and boost the voltage by responding to extremely sharp transients, such as by causing the controller to reduce the voltage on the side of the converter next to the supercapacitor bank by more than some multiple of a voltage reduction across the fuel cell stack lines 8, 9 in order to force more charge (more augmenting current) out of the supercapacitor bank.
  • the voltage at the electric storage device side of the DC/DC converter 22 will typically be a fraction of the fuel cell stack voltage.
  • the controller 19 may control the DC/DC converter in response either to the voltage related to the load, such as between the lines 8, 9, a voltage at the load 16, or a substack voltage (e.g., of a group of cells) within the stack 7.
  • Fig. 3 also illustrates that the source of hydrogen, instead of being derived from a reformer 13, may be a hydrogen tank 13a.
  • a conventional power conditioning system 15 receives the power over the output lines 8, 9 from the fuel cell stack 7 and provides power to the load 16. In some systems, where a power conditioning system is not necessary, the invention maybe utilized to drive the load 16 directly.
  • Fig. 4 illustrates that the electric energy storage device may comprise a bank of batteries 10 A.

Abstract

A fuel cell stack (7) with output lines (8, 9) has a bank of supercapacitors (10) or batteries (10a) connected across the output lines, either directly or through a DC/DC converter (22). The fuel cell stack receives fuel either from a reformer (13) or a source (13a) of hydrogen. Power is supplied through a power conditioning system (15) to a load (16), all under the control of a controller (19). The supercapacitors or batteries receive additional charge from excess power when there is a sudden decrease in the load, and provide charge to the output power lines (8, 9) when there is a sudden increase in load demand. In one embodiment, the voltage of the supercapacitors or batteries always follow the voltage of the fuel cell stack, thereby providing or receiving commensurate charge. With the DC/DC converter, the supercapacitors or batteries may be operated at voltages which are multiple or a fraction of fuel cell stack voltage, and may have voltages boosted or bucked to aid in response to transients.

Description

ELECTRIC STORAGE AUGMENTATION OF FUEL CELL SYSTEM TRANSIENT RESPONSE
Technical Field This invention relates to a fuel cell power plant having batteries or a bank of super capacitors connected electrically in parallel with the fuel cell stack, thereby to provide energy for increased load transients and to absorb energy during decrease load transients.
Background Art When a fuel cell stack assembly is operating normally and there is a sudden increase in the load, the capability of the fuel cell stack assembly to provide the required current is primarily a function of the amount of fuel resident in the fuel flow fields. If the fuel flow fields are designed so as to have a larger volume of fuel adjacent to the fuel cell membrane, the fuel cell stack assembly will have a greater increasing-load transient response capability. However, providing increased fuel volume in the fuel flow fields requires that the fuel channels be larger at the expense of thinner inter-channel ribs, which will decrease the strength of the fuel cell stack, and can lead to cracking of the fuel cells during assembly and other handling. On the other hand, providing a larger volume for each fuel cell would usually be prohibitive in automotive applications, such as where a fuel cell power plant provides the electricity for an electric vehicle. In order to achieve maximum fuel utilization, on the order of 90% or more, fuel recycle may be employed. In such a case, there is essentially no excess hydrogen resident in the fuel flow fields. Thus, the use of fuel recycle to boost system efficiency comes at the expense of a reduction in increased-load transient capability. A fuel cell power plant operating normally may undergo a sudden decrease in load. The fuel processing system, including valves and solenoids, lags in its response to this reduction in demand, so that a large amount of excess hydrogen is not consumed in the fuel cell stack. The excess hydrogen may pass into a downstream burner of some sort; the amount of hydrogen fed to the burner under a reduced-load transient may be several times the amount of hydrogen that the burner would normally have to handle, hi order to be able to consume the excess hydrogen, without causing equipment damage, the volume and burning capacity must be increased, which increases the overall volume and cost of the fuel cell power plant. If excess hydrogen is simply exhausted, it must be done so in a safe manner, such as by diluting the hydrogen to less than one percent; this may require increased ventilation capabilities in the entire fuel processing system. Tighter controls on the fuel control response rate may mitigate the problem of excess hydrogen, but it would never eliminate the problem entirely, and may add significant cost to a fuel cell system. The problem of excess fuel resulting from a sudden decrease in load is referred to in U.S. Patent 6,572,993. However, the system therein operates a storage device, such as a battery pack, a plurality of capacitors or a plurality of supercapacitors, at a nearly uniform level which is a predetermined percentage of the maximum charge level, such as 80%. In response to a sudden reduced load, the energy storage device absorbs excess energy generated by the fuel cell until the amount of fuel entering the anode is lowered to a level not to require the energy storage device to be necessary. At that time, the energy storage device dissipates the excess energy back to its original predetermined level. When the load returns to its previous, normal level, the energy storage device provides excess energy to maintain a desired power output level. As more fuel is provided to the anode, the storage level of the electric power and the energy storage device can be returned to its normal level. The foregoing patent, therefore, has a system in which steady state conditions are paramount, and transient dips in the load are accommodated by the manner in which the energy storage device is controlled to absorb excess energy, and to thereafter dissipate it, and at the end of the transient provides excess energy and is thereafter returned to its original predetermined level. If capacitors or supercapacitors are used as the electric storage device, since charge is equal to the voltage times the capacitance, and the charge is always set to a specific fraction, such as 80% of maximum charge, the system of said patent is always set to a fixed, certain, specific predetermined voltage, regardless of anything else. If batteries are used, the voltage will be constant, at any given level of charge. The aforementioned system will not satisfy the requirements of most modern applications of a fuel cell power plant upon which the demand varies continuously and significantly, such as a fuel cell power plant providing the power to an electric vehicle. Disclosure of Invention Aspects of the invention include: a fuel cell power plant which can readily handle abrupt increases and decreases in load; increased capability of the fuel cell stack to handle abrupt decreases in load, without weakening the fuel cell structure; provision of reformers for converting hydrocarbon fuel to hydrogen for use as a fuel cell fuel which may utilize slowly responding sensors and valves; cost effective production and utilization of hydrogen in a fuel cell stack; and an improved apparatus for converting hydrocarbon fuel to electricity by means of a reformer and a fuel cell stack. The invention is predicated on the realization that adjustments, not only in the amount of hydrogen required but also the power conditioning required to serve a widely varying load need not be made instantly, but may instead be instantly accommodated electrically, at the fuel cell output, provided suitable apparatus and operating methodology are employed. According to the present invention, the electrical output of a fuel cell power plant is controlled, either through actively controlled switching, with voltage conversion, or directly and passively, by an electrical storage bank, such as a bank of supercapacitors or batteries. The bank of supercapacitors or batteries is connected between the fuel cell stack and the output power conditioning system that feeds the load. In accordance with the invention in one form, an electrical storage bank is directly connected across the electrical output of a fuel cell stack, the voltage of the electrical storage device being allowed to follow completely, at all times, the voltage output of the fuel cell stack, without any intervening controls. The electric storage device thereby automatically provides or receives charge as necessary in order to maintain the voltage of the electric storage device substantially identical to the voltage of the fuel cell stack, with only a very slight lag, which is inconsequential. According to the invention in another form, the voltage of an electric storage device, such as a bank of supercapacitors or batteries, is isolated from the voltage of a fuel cell stack by means of a regenerative DC/DC converter. By handling shortages and excesses of electricity on the electrical side of the fuel cell stack, the production and/or application of hydrogen to the fuel cell stack can be regulated in a fashion which is much slower than the electrical load transients, without increased cost, endangering apparatus, or polluting the atmosphere, and the power conversion apparatus feeding a grid or other load can operate in a small range, with fewer constraints, and with more efficiency at lower cost.
Brief Description of the Drawings Fig. 1 is a simplified block diagram of a fuel cell power plant receiving fuel converted from hydrocarbon fuels by a reformer. Fig. 2 is a simplified schematic block diagram of a variant of the system illustrated in Fig. 1 which includes a DC/DC converter. Fig. 3 is a simplified schematic diagram of a variation of the configuration of Fig. 2, in which fuel for the fuel cell stack is derived from a source of hydrogen, such as a tank of hydrogen. Fig. 4 is a partial, simplified schematic diagram of the apparatus of Fig. 2, illustrating that the energy storage device may be a battery.
Mode(s) for Carrying Out the Invention Referring to Fig. 1 , a fuel cell power plant 6 includes a fuel cell stack 7 having electric output lines 8, 9 with an energy storage device, such as a supercapacitor bank 10, connected directly in parallel with the fuel cell stack 7 between the output lines 8, 9, in accordance with the invention, hi the embodiment herein, the fuel cell stack 7 receives hydrogen-containing fuel in a conduit 11 from a reformer 13 that converts hydrocarbon fuel from a source 14, which may, for example, be a catalytic partial oxidizer reformer system such as those disclosed in copending U.S. patent application Serial No. 10/369,359, filed February 18, 2003, or any other reformer suitable to provide innocuous hydrogen-rich fuel to a fuel cell stack. The power on the output lines 8, 9 is controlled for its intended use by a conventional power conditioning system 15, which applies the power to a load 16 which may be a grid, an electric vehicle motor, or any other load. As used herein, the term Aload® may mean the load 16, or it may mean the power conditioning system 15 and the load 16. With a supercapacitor bank 10 in parallel with the fuel cell stack 7, when the load 16 decreases, the controller 19 will cause less fuel to enter the fuel supply 14. There is, however, a surplus of hydrogen in the fuel cell stack and fuel supply system. As the load 16 decreases, the voltage on power output lines 8 and 9 increases. This causes the voltage in the supercapacitors to increase and they increase in charge. The increase in charge to the supercapacitors consumes the excess power from the surplus hydrogen, which mitigates the duty on the fuel cell stack exhaust system ventilation or burner (not shown). When the load 16 increases, the controller 19 will cause more fuel to enter the fuel cell stack by opening the fuel inlet valve in a conventional fashion, and will cause more hydrocarbon fuel to enter the reformer by opening the inlet valve thereof, along with other adjustments. However, before the amount of fuel can be ramped up to the required new level, the fuel cell stack will not be performing adequately to handle the load. With increased current level provided by the fuel cell stack, the average cell voltage will drop, dropping the voltage of the supercapacitor bank 10, causing charge to flow out of the supercapacitor bank, thereby supplying current to the power conditioning system 15. Thus, the supercapacitor bank 10 is passively controlled, automatically, by being connected directly in parallel with the electric output of the fuel cell stack 7. With the invention, current flows from the supercapacitor bank 10 into the power conditioning system 15 to satisfy the power needs of the load 16 in response only to the voltage of the fuel cell stack electric output on lines 8, 9. The controller 19 will eventually ramp up the amount of hydrogen produced by the reformer 13 and the amount of hydrogen-rich fuel admitted from the conduit 11 into the anodes of the fuel cell stack 7. As that happens, the supercapacitor bank 10, in accordance with the invention, will simply continue to track the voltage of the fuel cell stack output on the lines 8, 9, thereby being continuously able to respond to any variations in the load, at any stage of transients or restoration of fuel equity with respect to load. In the embodiment of Fig. 1, this is done passively, simply because of the direct parallel connection of the supercapacitor bank between the output lines 8, 9 of the fuel cell stack 7, without any intervening controls. Thus, in this embodiment of the invention, there is no need for any controls to restore a charge level of the supercapacitor bank in any fashion whatsoever, it being done automatically and passively. In the embodiment of Fig. 1, the supercapacitor bank 10 is passive, that is, it simply receives or delivers electric charge in dependence on the voltage on the lines 8, 9 being greater or lesser than the voltage in the supercapacitor bank. Because the supercapacitor bank follows the voltage of the fuel cell stack at all times, it will always, except during actual transients, be at the voltage of the fuel cell stack, and therefore be ready to respond to either a higher voltage by receiving charge or a lower voltage by delivering charge. If desired to suit any given implementation of the present invention, the supercapacitor bank charge and discharge functions can be augmented with a conventional regenerative DC/DC converter 22, shown in Fig. 2. The DC/DC converter will be most advantageous in circumstances where the transients may be extremely rapid and large, so that the voltage of the supercapacitor bank may not be high enough to drive the increase in load, and in similar situations where the voltage transitions to much lower voltages will be so great that the supercapacitor bank will not accept the charge unless it is raised to a higher voltage. Use of the converter 22 allows for a greater removal of energy (i.e., a deeper discharge). In the embodiment of Fig. 2, by utilizing the DC/DC converter 22, the supercapacitor bank 10 may operate at voltages which are, for instance, substantially different from the voltage of the fuel cell stack on the lines 8, 9. As an example, the supercapacitor bank 10 may be operated in a range of voltages that approach several hundred volts, while the fuel cell stack may operate at voltages ranging from around 250 volts dc to around 450 volts dc, in a normal operation. In the embodiment of Fig. 2, the DC/DC converter can not only convert the voltage to some multiple or fraction of the fuel cell stack voltage, but can also buck and boost the voltage by responding to extremely sharp transients, such as by causing the controller to reduce the voltage on the side of the converter next to the supercapacitor bank by more than some multiple of a voltage reduction across the fuel cell stack lines 8, 9 in order to force more charge (more augmenting current) out of the supercapacitor bank. The voltage at the electric storage device side of the DC/DC converter 22 will typically be a fraction of the fuel cell stack voltage. The controller 19 may control the DC/DC converter in response either to the voltage related to the load, such as between the lines 8, 9, a voltage at the load 16, or a substack voltage (e.g., of a group of cells) within the stack 7. Fig. 3 also illustrates that the source of hydrogen, instead of being derived from a reformer 13, may be a hydrogen tank 13a. hi the embodiments herein, a conventional power conditioning system 15 receives the power over the output lines 8, 9 from the fuel cell stack 7 and provides power to the load 16. In some systems, where a power conditioning system is not necessary, the invention maybe utilized to drive the load 16 directly. Fig. 4 illustrates that the electric energy storage device may comprise a bank of batteries 10 A.

Claims

Claims
1. A fuel cell power plant (6) comprising: a fuel cell stack (7) having electric power output lines (8, 9); a source of fuel (13, 14) connected to said fuel cell stack; said electric output power lines connected to either (a) a load (16) or (b) a power conditioning system (15) feeding a load; a controller (19), said controller controlling supplied fuel to said fuel cell stack; characterized by: an electric energy storage device (10) either (c) connected directly in parallel with said fuel cell stack between said electric output power lines so that the voltage of said fuel cell stack always follows the voltage between said electric output power lines and is always substantially the same voltage as the voltage between said electric output power lines, or (d) connected to a DC/DC converter (22), said DC/DC converter and said electric energy storage device being connected in series between said electric output power lines.
2. A power plant according to claim 1 wherein: said energy storage device is one or more supercapacitors (10).
3. A power plant according to claim 1 wherein: said energy storage devices is one or more batteries (10A).
4. A fuel cell power plant (6) providing power to a load (16) having a fuel cell stack (7) with electric output power lines (8, 9) comprising: an electric energy storage device (10) associated with said fuel cell stack; characterized by: means (22) for providing a voltage to said electric energy storage device which is always either (a) substantially a multiple or (b) substantially a fraction of the voltage between said electric output power lines; and means (19) for controlling the voltage provided to said electric energy storage device in response to a voltage related to said load.
5. A method of operating a fuel cell power plant (6) having a fuel cell stack (7) with electric output power lines (8, 9) providing power to a load (16) and an electric energy storage device (10) associated with said fuel cell stack, characterized by: providing (22) a voltage to said electric energy storage device which is always either (a) substantially a multiple or (b) substantially a fraction of the voltage between said electric output power lines; and controlling (19) the voltage provided to said electric energy storage device in response to a voltage related to said load.
6. A method according to claim 5 wherein: said controlling step comprises (c) increasing or (d) decreasing said voltage provided to said electric storage device (10) above or below said multiple or said fraction to increase response of said electric storage device to load transients.
7. A method of operating a fuel cell power plant (6) providing power to a load (16) having a fuel cell stack (7) with electric output power lines (8, 9) and an electric energy storage device (10) associated with said fuel cell stack, characterized by: connecting said electric energy storage device directly between said electric output power lines in parallel with said fuel cell stack; and allowing the voltage of said electric energy storage device to follow the voltage across said electric output power lines, whereby the voltage of said electric storage device always follows the voltage between said electric output power lines and is always substantially the same voltage as the voltage between said electric output power lines.
PCT/US2004/038719 2003-11-19 2004-11-17 Electric storage augmentation of fuel cell system transient response WO2005053061A2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP04811433.4A EP1692736B1 (en) 2003-11-19 2004-11-17 Electric storage augmentation of fuel cell system transient response
JP2006541375A JP2007511891A (en) 2003-11-19 2004-11-17 Storage expansion of fuel cell system transient response

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/717,089 2003-11-19
US10/717,089 US7087329B2 (en) 2003-11-19 2003-11-19 Electric storage augmentation of fuel cell system transient response

Publications (2)

Publication Number Publication Date
WO2005053061A2 true WO2005053061A2 (en) 2005-06-09
WO2005053061A3 WO2005053061A3 (en) 2005-06-30

Family

ID=34574519

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2004/038719 WO2005053061A2 (en) 2003-11-19 2004-11-17 Electric storage augmentation of fuel cell system transient response

Country Status (4)

Country Link
US (1) US7087329B2 (en)
EP (1) EP1692736B1 (en)
JP (1) JP2007511891A (en)
WO (1) WO2005053061A2 (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6991864B2 (en) 2003-09-23 2006-01-31 Utc Fuel Cells, Llc Storage of fuel cell energy during startup and shutdown
ITTO20040054A1 (en) * 2004-02-04 2004-05-04 Fiat Ricerche INNOVATIVE ARCHITECTURES OF ENERGY GENERATION AND DISTRIBUTION SYSTEMS ON BOARD MOTOR VEHICLES
US7700210B2 (en) * 2005-05-10 2010-04-20 Bloom Energy Corporation Increasing thermal dissipation of fuel cell stacks under partial electrical load
JP2007109609A (en) * 2005-10-17 2007-04-26 Omron Corp Charging and discharging device of fuel cell system
US20070285048A1 (en) * 2006-06-12 2007-12-13 Leach David H Fuel cell charger interface with multiple voltage outputs for portable devices
US20080277175A1 (en) * 2007-05-07 2008-11-13 Ise Corporation Fuel Cell Hybrid-Electric Heavy-Duty Vehicle Drive System and Method
DE102007049081A1 (en) * 2007-10-12 2008-07-24 Daimler Ag Fuel cell system operating method for use in motor vehicle, involves regulating intermediate circuit voltage in electrical power line to preset value, where voltage is provided by fuel cell system and is regulated by regulator
US20090179609A1 (en) * 2008-01-11 2009-07-16 Gm Global Technology Operations, Inc. HV Battery Equalization Charge During Driving Operation in Fuel Cell Hybrid Vehicles
KR101143867B1 (en) 2008-04-24 2012-05-24 호발츠벨케 도이췌 벨프트 게엠베하 Method for energy supply
US7952231B1 (en) * 2008-10-31 2011-05-31 Netapp, Inc. Method and system for providing supplemental power
US8553381B2 (en) 2011-05-27 2013-10-08 Hamilton Sundstrand Corporation Gradually reducing resistive clamp
JP6365275B2 (en) 2014-12-04 2018-08-01 オムロン株式会社 Storage battery control device, power storage system, and storage battery charging method
US11127538B2 (en) 2017-02-20 2021-09-21 The Research Foundation For The State University Of New York Multi-cell multi-layer high voltage supercapacitor apparatus including graphene electrodes
CN109823235B (en) * 2019-02-20 2021-10-01 中国科学技术大学 Energy management system of hybrid energy storage device of battery, super capacitor and fuel cell

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6572993B2 (en) 2000-12-20 2003-06-03 Visteon Global Technologies, Inc. Fuel cell systems with controlled anode exhaust
US20030194586A1 (en) 2002-04-11 2003-10-16 Toyota Jidosha Kabushiki Kaisha Power supply system and control method of the same

Family Cites Families (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2989353B2 (en) * 1991-11-29 1999-12-13 三洋電機株式会社 Hybrid fuel cell system
JP3687991B2 (en) * 1994-02-24 2005-08-24 株式会社エクォス・リサーチ Hybrid power supply
JP3487952B2 (en) * 1995-04-14 2004-01-19 株式会社日立製作所 Drive device and drive control method for electric vehicle
US5777454A (en) * 1996-05-29 1998-07-07 Peco Ii, Inc. Back-up battery management system for a DC power supply
US6484830B1 (en) * 2000-04-26 2002-11-26 Bowling Green State University Hybrid electric vehicle
EP1433239B1 (en) * 2000-07-28 2016-03-30 International Power Systems,Inc. Dc to dc converter and power management system
JP3757775B2 (en) * 2000-09-27 2006-03-22 日産自動車株式会社 Power control device for fuel cell vehicle
JP3662872B2 (en) * 2000-11-17 2005-06-22 本田技研工業株式会社 Fuel cell power supply
JP2002324562A (en) * 2001-04-27 2002-11-08 Mitsubishi Heavy Ind Ltd Fuel cell power-generating system and operating method therefor
JP4130319B2 (en) * 2001-07-10 2008-08-06 本田技研工業株式会社 Fuel cell control device
US6794844B2 (en) * 2001-08-31 2004-09-21 Visteon Global Technologies, Inc. Method and system for fuel cell control
US6737762B2 (en) * 2001-10-26 2004-05-18 Onan Corporation Generator with DC boost for uninterruptible power supply system or for enhanced load pickup
JP3810307B2 (en) * 2001-11-27 2006-08-16 大阪瓦斯株式会社 Power supply
US6841275B2 (en) * 2001-12-14 2005-01-11 Ballard Power Systems Inc. Method and apparatus for controlling voltage from a fuel cell system
KR20030050139A (en) * 2001-12-18 2003-06-25 현대자동차주식회사 Electric power system on fuel cell hybrid electric vehicle
US6881509B2 (en) * 2001-12-19 2005-04-19 Abb Research Ltd. Fuel cell system power control method and system
JP3744456B2 (en) * 2002-04-08 2006-02-08 日産自動車株式会社 Control device for vehicle equipped with fuel cell
KR100460881B1 (en) * 2002-06-28 2004-12-09 현대자동차주식회사 System and method for controlling power conversion of fuel cell hybrid electric vehicle
KR20040009370A (en) * 2002-07-23 2004-01-31 현대자동차주식회사 Method of controlling output power of fuel cell for fuel cell hybrid electric vehicle

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6572993B2 (en) 2000-12-20 2003-06-03 Visteon Global Technologies, Inc. Fuel cell systems with controlled anode exhaust
US20030194586A1 (en) 2002-04-11 2003-10-16 Toyota Jidosha Kabushiki Kaisha Power supply system and control method of the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1692736A4

Also Published As

Publication number Publication date
EP1692736A4 (en) 2009-06-24
US20050106432A1 (en) 2005-05-19
EP1692736B1 (en) 2013-10-02
EP1692736A2 (en) 2006-08-23
WO2005053061A3 (en) 2005-06-30
JP2007511891A (en) 2007-05-10
US7087329B2 (en) 2006-08-08

Similar Documents

Publication Publication Date Title
JP3657582B2 (en) Fuel cell control system
US6369461B1 (en) High efficiency power conditioner employing low voltage DC bus and buck and boost converters
US7087329B2 (en) Electric storage augmentation of fuel cell system transient response
CN100570934C (en) The DC power supply that has fuel cell
CN101868881B (en) Fuel cell system
US7829229B1 (en) Power control for hybrid fuel cell systems
JP5005809B2 (en) Power conversion control method and control device for fuel cell-battery hybrid electric vehicle
KR101867653B1 (en) Dc/dc power converter control strategy for source protection
US7808129B2 (en) Fuel-cell based power generating system having power conditioning apparatus
CN102474177A (en) Converter controller
JP5732596B2 (en) Method for controlling the operation of a hybrid system
US8427097B2 (en) Hybrid electrical power source
US8889276B2 (en) Method for managing the operation of a hybrid system
Kisacikoglu et al. Fuzzy logic control of a fuel cell/battery/ultra-capacitor hybrid vehicular power system
US8604637B2 (en) Method for high voltage bus control in fuel cell vehicles
KR101020200B1 (en) Power controlling method of Fuel cell and Fuel cell system
KR101879646B1 (en) System for fuel cell
Lucken et al. Analysis of different methods to improve the fuel cell dynamics for modern aircraft applications
KR20030050139A (en) Electric power system on fuel cell hybrid electric vehicle
Cervantes et al. Hybrid control technique applied in a fc-sc electric vehicle platform
Latha et al. Investigation of various operating modes of fuelcell/ultracapacitor/multiple converter based hybrid system
KR20220102060A (en) A Fuel Cell Hybrid System with Independent Power Generation
Greenwell Real-time power management of a fuel cell/ultracapacitor hybrid
CN117124852A (en) Power supply control method and active fuel cell system
KR20100036021A (en) Power controlling method of fuel cell and fuel cell system

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DPEN Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed from 20040101)
WWE Wipo information: entry into national phase

Ref document number: 2006541375

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

WWE Wipo information: entry into national phase

Ref document number: 2004811433

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2004811433

Country of ref document: EP