WO2010042085A1 - Système et procédé permettant de détecter des tensions de sous-empilement - Google Patents

Système et procédé permettant de détecter des tensions de sous-empilement Download PDF

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Publication number
WO2010042085A1
WO2010042085A1 PCT/US2008/011513 US2008011513W WO2010042085A1 WO 2010042085 A1 WO2010042085 A1 WO 2010042085A1 US 2008011513 W US2008011513 W US 2008011513W WO 2010042085 A1 WO2010042085 A1 WO 2010042085A1
Authority
WO
WIPO (PCT)
Prior art keywords
sensor element
substack
fluid
monitoring system
pressure plate
Prior art date
Application number
PCT/US2008/011513
Other languages
English (en)
Inventor
Richard Jonathan Spadaccini
Michael D. Harrington
Original Assignee
Utc Power Corporation
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 Power Corporation filed Critical Utc Power Corporation
Priority to PCT/US2008/011513 priority Critical patent/WO2010042085A1/fr
Publication of WO2010042085A1 publication Critical patent/WO2010042085A1/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
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • 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
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/04664—Failure or abnormal function
    • H01M8/04679—Failure or abnormal function 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
    • H01M8/04955—Shut-off or shut-down of fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present disclosure relates in general to the monitoring of voltages in fuel cell power plants, and more particularly, to a system and method of sensing and monitoring substack voltages in electrochemical cell stack assemblies.
  • Fuel cell power plants are well known for converting chemical energy into usable electrical power. Fuel cell power plants usually comprise multiple fuel cells arranged in a repeating fashion to form a cell stack assembly ("CSA"), including internal ports or external manifolds connecting coolant fluid and reactant gas flow passages or channels. Each individual fuel cell in a CSA typically includes a proton exchange membrane (“PEM”) sandwiched between an anode electrode and a cathode electrode to form a membrane electrode assembly (“MEA"). On either side of the MEA are electrically conductive bipolar plates in electrical communication with the MEA that comprise reactant flow fields for supplying a reactant fuel (e.g. hydrogen) to the anode, and a reactant oxidant (e.g. oxygen or air) to the cathode.
  • a reactant fuel e.g. hydrogen
  • a reactant oxidant e.g. oxygen or air
  • the hydrogen electrochemically reacts with a catalyst layer disposed on the anode side of the PEM to produce positively charged hydrogen protons and negatively charged electrons.
  • the anode side of the PEM only allows the hydrogen protons to transfer through the membrane to the cathode side, forcing the electrons to follow an external path through a circuit to power a load before being conducted to the cathode.
  • the hydrogen protons and electrons eventually come together at a catalyst layer disposed on the cathode side of the PEM, they combine with the oxidant to produce water and thermal energy.
  • Each fuel cell produces a relatively small voltage, for example, around one volt, and the stacking of multiple fuel cells in electrical series increases the overall voltage produced by the stack incrementally by each fuel cell added from the anode to the cathode end of the stack.
  • a CSA comprising 50 fuel cells may produce around 50 volts under normal operating conditions, whereas a CSA comprising 25 fuel cells will produce around 25 volts.
  • individual fuel cells or groups of cells do not always operate efficiently or properly, for reasons including corrosion of catalysts and obstruction of reactant and coolant channels.
  • One method for determining the health of a CSA is by monitoring the individual voltages of the fuel cells (herein referred to as "substack voltages").
  • a substack voltage measurement of less than five volts taken at the fifth fuel cell with reference to the anode may indicate a problem with the health of fuel cells one through five, such as insufficient reactant flow, overheating, or otherwise.
  • Typical substack voltage monitoring techniques involve placing a sensor in contact with a fuel cell bipolar plate and another sensor in contact with a reference.
  • the reference may be, for example, a ground reference such as a pressure plate, or can be another fuel cell bipolar plate spaced apart from the first.
  • a portion of the bipolar plate is normally exposed on an exterior surface of the stack, making it easy to contact with a sensor.
  • the bipolar plates and other conductive fuel cell components are normally obstructed by the manifold assembly.
  • wire is typically routed underneath an air manifold seal and into an air flow field to a sensor in mechanical contact with a bipolar plate.
  • this mechanical connection is prone to failure under common physical stresses such as rapid heating and cooling of the stack, in addition to vibration experienced in automotive applications. If the sensor breaks off of the bipolar plate, it can lead to loss of substack voltage data in addition to the inconvenience of having to remove the entire manifold assembly in order to repair the broken wire or sensor.
  • running wire under an external manifold seal provides a potential leak path for reactants.
  • the present disclosure relates to a system and method for sensing substack voltage measurements in an electrochemical cell stack assembly using sensor elements positioned in contact with fluid in the cell stack assembly.
  • the fluid has an electrical potential that varies from the anode to cathode end of the stack as a function of each individual cell in the stack.
  • FIG. 1 is a perspective view of an embodiment of the present disclosure, including a cross section of an external coolant exit manifold.
  • FIG. 2 is a cross sectional view of a cell stack assembly, including an embodiment of the present disclosure.
  • Described herein is a system and method for sensing substack voltages using sensor elements positioned to contact fluid within a CSA external manifold.
  • This invention is predicated in part on the discovery that fluid present in an operating CSA has an electrical potential that varies from an anode end to a cathode end of the stack as a function of each individual cell in the stack.
  • the electrical potential at a given cell can be measured in fluid that is in electrical communication with the fuel cell.
  • Sensors in contact with fluid are not in direct mechanical connection with a rigid fuel cell component such as a bipolar plate, and thus possess the advantage of being less prone to mechanical failure over time in response to normal operating stresses such as physical vibration and sudden temperature swings.
  • FIG. 1 is a perspective view of CSA 10, showing a cross section of external fluid manifold 12, including fluid manifold space 14, air manifold space 16, manifold seal 18, and fuel cell stack 20 comprising individual fuel cells arranged in series from anode end 22 to cathode end 24, the stack sandwiched between pressure plates 26 (both plates shown in FIG. 2). Due to the arrangement of the fuel cells in series, the electrical potential from anode end 22 to cathode end 24 of stack 20 will increase as a function of each individual cell.
  • Stack 20 connected to an external load normally forms an electrically closed circuit that is insulated from other components of CSA 10, such as fluid manifold 12, in order to prevent short circuiting.
  • fluid including water or glycol-based coolants
  • Stack 20 connected to an external load normally forms an electrically closed circuit that is insulated from other components of CSA 10, such as fluid manifold 12, in order to prevent short circuiting.
  • fluid including water or glycol-based coolants
  • CSA 10 carries a current and has an electrical potential measurable using the system and method of the present disclosure, even in parts of CSA 10 insulated from stack 20, such as in fluid manifold space 14.
  • This phenomenon can be explained by the electrically conductive elements that comprise the stack 16 components, including the fluid channels (not shown), combined with the ionic content of fluid in communication with stack 16. Because the ionic content for fluid will be minimal, electrical current in the fluid will face a high resistance and will likewise be minimal, preventing stack 16 from short circuiting.
  • the electrical potential present in the fluid will be a function of location
  • FIG. 1 shows an embodiment of the present disclosure for measuring substack voltages.
  • Sensor element 28 and sensor element 30 comprise wire lead 32 extending through cap fitting 34, through electrically insulative sheath 36, and ending in exposed wire electrode portion 38.
  • Each cap fitting 34 penetrates external fluid manifold 12 and is preferably sealed so as to prevent leakage of fluid into the external environment.
  • reference sensor element 40 may also be used, comprising a wire lead 42 operably connected with any location on pressure plate 26, in which case pressure plate 26 will act as an electrode due to its electrically conductive nature and electrical continuity with stack 16 components.
  • exposed wire electrodes 38 are positioned to contact fluid (now shown) in fluid manifold space 14 at location 44 and location 46 near a fuel cell but not in actual contact with any fuel cell components, such as a bipolar plate. It may be appreciated that for each sensor element, any location can be chosen based on which substack voltage is to be measured, and that any number of sensor elements may be utilized. While fluid is present in manifold space 14 during operation of stack 20 to produce electrical power, an electrical potential can be measured between any two sensor elements to indicate a substack voltage measurement. This may be done, for example, by attaching a voltmeter or substack voltage monitor to wire leads 32, 42.
  • Reference sensor element 40 on pressure plate 26 at anode end 22 may be used to indicate zero volts relative to sensor element 28 or sensor element 30. For example, if location 44 of sensor element 28 is nearest the fifth fuel cell in stack 20 proceeding from anode end 22 to cathode end 24, a substack voltage measurement relative to reference sensor element 40 can be indicated for the fifth cell (e.g., five volts for a healthy stack 20 producing one volt per cell). Similarly, if location 46 for sensor element 30 is nearest the thirty-fifth cell in stack 20, a substack voltage measurement relative to reference sensor element 40 can be indicated for the thirty-fifth cell (e.g., thirty-five volts for a healthy stack 20 producing one volt per cell).
  • sensor element 28 may be used as a zero volt reference in relation to sensor element 30 for providing a positive substack voltage measurement at a fuel cell closest to location 46. It may be appreciated that other sensor elements could be used that differ in construction from the specific sensor elements depicted in FIG. 1, for example, a simple wire lead and electrode used for standard commercially available multimeters or a printed circuit board with pins penetrating the manifold and making contact with coolant.
  • FIG. 2 is a cross sectional view of a CSA 1OA having an external coolant manifold 48 containing coolant 50, fuel cell stack 52 comprising fuel cells 1, 2, 3, 4, 5, 6, 7, and 8, anode pressure plate 54, cathode pressure plate 56, and sensor element 58, 60, 62, 64, 66 and 68.
  • Sensor elements 60, 62, 64, and 66 are shown penetrating the external coolant manifold wall, and may comprise a simple insulated wire with exposed electrode portion for contacting the coolant near a particular fuel cell, or could comprise the structure described with reference to FIG. 1.
  • Coolant 50 may partially or completely fill external coolant manifold 48, which can be a coolant inlet or coolant exit manifold, and will have an electrical potential that increases from anode pressure plate 54 to cathode pressure plate 56 as a function of each fuel cell 1, 2, 3, 4, 5, 6, 7, and 8 along the stack 52.
  • external coolant manifold 48 can be a coolant inlet or coolant exit manifold, and will have an electrical potential that increases from anode pressure plate 54 to cathode pressure plate 56 as a function of each fuel cell 1, 2, 3, 4, 5, 6, 7, and 8 along the stack 52.
  • the system and method of the present disclosure can be practiced in a coolant inlet manifold to ensure continual contact of sensor elements 58, 60, 62, 64, 66 and 68 with coolant 50 and uninterrupted substack voltage readings during operation of CSA 1OA.
  • Fuel cell stack 52 is shown having eight fuel cells and only six sensor elements for the sake of simplicity, however, a stack 52 having any number of fuel cells and sensor elements may be used with the system and method of the present disclosure.
  • sensor element 60, 62, 64, and 66 the electrode for each sensor element is shown in contact with coolant 50 near fuel cell 2, 4, 5, and 7, respectively.
  • FIG. 2 further shows an embodiment of the present disclosure for measuring substack voltages using substack voltage monitor 70 having voltage input board 72 comprising voltmeter 72A, 72B, 72C, 72D, and 72E.
  • Each voltmeter is connected to wires - voltmeter 72A to wires 74 and 76, voltmeter 72B to wires 78 and 80, voltmeter 72C to wires 82 and 84, voltmeter 72D to wires 86 and 88, voltmeter 72E to wires 90 and 92 - and each wire is further connected to a sensor element - wire 74 to sensor element 58, wires 76 and 78 to sensor element 60, wires 80 and 82 to sensor element 62, wires 84 and 86 to sensor element 64, wires 88 and 90 to sensor element 66, and wire 92 to sensor element 68.
  • each voltmeter is configured to receive an analog electrical potential signal from a pair of sensor elements, at least one sensor of each pair positioned in contact with coolant 50 near
  • voltmeter 72 A will receive a substack voltage measurement of two volts between sensor element 60 nearest fuel cell 2 and sensor element 58 positioned on anode pressure plate 54.
  • Voltmeter 72B will produce a substack voltage measurement of two volts between sensor element 62 nearest fuel cell 4 and sensor element 60 nearest fuel cell 2.
  • Voltmeter 72C will produce a substack voltage measurement of one volt between sensor element 64 nearest fuel cell 5 and sensor element 62 nearest fuel cell 4.
  • Voltmeter 72D will produce a substack voltage measurement of two volts between sensor element 66 positioned nearest fuel cell 7 and sensor element 64 nearest fuel cell 5.
  • voltmeter 72E will produce a substack voltage measurement of one volt between sensor element 68 positioned on cathode pressure plate 56 and sensor element 66 positioned nearest fuel cell 7.
  • the sum of substack voltage measurements should equal a total value of eight volts representing the electrical potential from anode pressure plate 54 to cathode pressure plate 56 (i.e., anode terminal to cathode terminal) of stack 52.
  • the number and particular distribution of sensor elements may vary depending on how many substack voltages measurements are necessary to properly indicate the health of a CSA.
  • Voltage input board 72 of substack voltage monitor 70 may comprise a standard analog-to-digital board, such as available from National Instruments, and takes each analog electrical potential signal received by each voltmeter 72A, 72B, 72C, 72D, and 72E and converts it to a digital signal. The digital signals may then be fed to a digital device, enabling appropriate processing of substack voltage measurement data and monitoring of CSA 1OA health. For example, digital substack voltage measurement data could be sent to a controller 94 for automated processing of the data and response to irregular readings, including but not limited to shutting the fuel cell power plant down, increasing or decreasing reactant flow through CSA 1OA, and increasing or decreasing coolant 50 flow.
  • Controller 94 may further comprise a readout device, such as an LCD screen, for viewing by an operator of CSA 1OA.
  • a readout device such as an LCD screen
  • Controller 94 may further comprise a readout device, such as an LCD screen, for viewing by an operator of CSA 1OA.
  • an insufficient level of coolant 50 in CSA 1OA could be indicated as described in related application entitled, "Voltage-Based Fluid Sensor for a Fuel Cell Stack Assembly," owned by the same applicant, which is incorporated by reference.
  • the system and method of the present disclosure may be used for the dual purpose of monitoring both substack voltage measurements as well as indicating proper coolant 50 levels in a CSA.

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

Abstract

Les tensions de sous-empilement dans un ensemble empilement de cellules (10) sont détectées à l’aide d’éléments de capteur (28, 30) placés en contact avec le fluide dans un collecteur de fluide (12) à des emplacements (44, 46) situés entre l’extrémité d’anode (22) et l’extrémité de cathode (24) d’un empilement (20). Le fluide a un potentiel électrique variant de l’extrémité d’anode (22) à l’extrémité de cathode (24) en fonction du potentiel électrique à travers l’empilement (20) de manière à ce qu’une tension mesurée entre les éléments de capteur (28, 30) et/ou entre un des éléments de capteurs (28, 30) et l’élément de capteur de référence (40) indique une mesure de tension de sous-empilement de l’empilement (20).
PCT/US2008/011513 2008-10-06 2008-10-06 Système et procédé permettant de détecter des tensions de sous-empilement WO2010042085A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2008/011513 WO2010042085A1 (fr) 2008-10-06 2008-10-06 Système et procédé permettant de détecter des tensions de sous-empilement

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Application Number Priority Date Filing Date Title
PCT/US2008/011513 WO2010042085A1 (fr) 2008-10-06 2008-10-06 Système et procédé permettant de détecter des tensions de sous-empilement

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114236407A (zh) * 2021-12-16 2022-03-25 海南大学 能量转换装置的性能损失测定方法及装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003081762A1 (fr) * 2002-03-18 2003-10-02 Sri International Dispositifs de polymere electro-actif pour deplacement de fluide
US20070134527A1 (en) * 2005-12-14 2007-06-14 Desouza Andrew J Hydration sensor apparatus for measuring membrane hydration in a fuel cell stack
US20070154755A1 (en) * 2005-12-30 2007-07-05 Wardrop David S Apparatus for measuring an electrical characteristic of an electrochemical device
US20080120046A1 (en) * 2006-11-22 2008-05-22 Chun-Chin Tung Fluid metering apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003081762A1 (fr) * 2002-03-18 2003-10-02 Sri International Dispositifs de polymere electro-actif pour deplacement de fluide
US20070134527A1 (en) * 2005-12-14 2007-06-14 Desouza Andrew J Hydration sensor apparatus for measuring membrane hydration in a fuel cell stack
US20070154755A1 (en) * 2005-12-30 2007-07-05 Wardrop David S Apparatus for measuring an electrical characteristic of an electrochemical device
US20080120046A1 (en) * 2006-11-22 2008-05-22 Chun-Chin Tung Fluid metering apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114236407A (zh) * 2021-12-16 2022-03-25 海南大学 能量转换装置的性能损失测定方法及装置

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