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
  • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
  • H01M8/04044—Purification of heat exchange media
• • 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
  • H01M8/02—Details
  • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
  • H01M8/0267—Collectors; Separators, e.g. bipolar separators; Interconnectors having heating or cooling means, e.g. heaters or coolant flow channels
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
  • H01M8/04029—Heat exchange using liquids
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
  • H01M8/04059—Evaporative processes for the cooling of a fuel cell
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
  • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
  • H01M8/04104—Regulation of differential pressures
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
  • H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
• • 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
  • H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
• • 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
  • H01M8/2465—Details of groupings of fuel cells
  • H01M8/2483—Details of groupings of fuel cells characterised by internal manifolds
• • 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
  • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
  • H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
• • 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 sensing the presence of excessive ingestion of gas in the coolant channels of a fuel cell stack, so that irreversible damage to the fuel cell stack may be avoided.
• bubble pressure is relied on to keep an interface between the gas (on the side of the reactant gas channels) and the water (on the side of the coolant channels). Bubble pressure is discussed in application publication US2004/0106034. If bubble pressure is lost, gas ingests into the coolant system at a rate which may be between 10 and 100 times greater than the normal rate of gas ingestion. The excessive gas in the coolant system may cause dryout of the proton exchange membrane, and possible failure thereof, reactant starvation, and system safety hazards.
• aspects of the invention include: detecting excessive ingestion of gas into the coolant of fuel cell stacks; preventing irreversible damage due to gas ingestion in fuel cell stack coolant channels; improved PEM fuel cell power plants.
• a gas flow detector is disposed in line with a gas vent that vents a fuel cell stack coolant flow path.
• the gas flow detectors are disposed on an accumulator vent.
• the gas flow detector sensor is disposed at a gas vent of the coolant channels.
• the gas flow detectors may each comprise a pressure sensor between the coolant channel or accumulator gas vent and an orifice leading to ambient. Excessive pressure indicates excessive ingestion of gas into the coolant.
• the pressure sensor may be a simple pressure switch. In systems employing the present invention, excessive gaseous flow from a vent through the orifice of the invention will create a substantial pressure drop, the increase of which is readily sensed so as to permit the controller to take measures to avoid damage to the system, such as shutting the power plant down or increasing the differential between the coolant water pressure and the pressure of reactant gases.
• FIG. 1 is a simplified, stylized, block diagram of a portion of a fuel cell power plant using convective cooling with circulating water flow and incorporating the present invention.
• Fig.2 is a simplified, stylized, block diagram of a portion of a fuel cell power plant employing evaporative cooling and incorporating the present invention.
• a fuel cell power plant 9 includes a fuel cell stack 10 having anodes 11, cathodes 12 and coolant channels 13.
• the anodes 11 receive hydrogen from a hydrogen system 16 which may either supply a hydrogen-rich reformate gas or substantially pure hydrogen (such as commercial-grade hydrogen).
• a hydrogen system 16 which may either supply a hydrogen-rich reformate gas or substantially pure hydrogen (such as commercial-grade hydrogen).
• the cathodes 12 receive (as oxidant reactant gas) air from a pump 18 that is fed from ambient air 19 through a filter 20, in a conventional way. After passing through the oxidant reactant gas channels of the cathodes 12, the air is expelled to exhaust 23.
• water is continuously circulated through the coolant channels 13, from a coolant inlet 26 through the channels in each of the fuel cells, and thence through a coolant outlet manifold 27 to a coolant pump 28.
• the pump 28 draws the liquid through the coolant channels and passes it through a heat exchanger 29 where it may be cooled, when necessary, by exchange with a non-freezable liquid (such as polyethylene glycol) circulating through the heat exchanger 29 by means of a pump 32.
• the pump 32 draws the coolant through another heat exchanger 34 which is cooled by a fan 36, all of which is under the control of a controller 39.
• the coolant flows from the heat exchanger 29 into a liquid air separator 40, the liquid being transmitted by a conduit 41 to the coolant inlet manifold 29 through a pressure control valve 42, which permits adjusting the pressure of the coolant in the coolant channels to assure proper bubble pressure, as described hereinbefore.
• the gas vent 45 of the separator 40 is connected to a pressure sensor 46, through an orifice 47 to exhaust (such as ambient).
• the pressure sensor may simply provide a signal indicative of pressure to the controller 39, or it may be a switch which either goes on or off as a function of a pressure deemed to be excessive, thereby indicating too much flow of gas through the orifice 47 and hence too much leakage into the coolant channels 13.
• the controller may respond in any of a number of ways, or in a combination of ways. For instance, the controller may simply shut the system down by causing the reactant flows to cease, in accordance with a conventional shutdown routine. On the other hand, the controller may adjust the relative pressure between the reactant gases in the anodes and cathodes and the water in the coolant channels 13. This may be achieved by adjusting the coolant channel water pressure by means of the valve 42 and/or the speed of the pump 28, or by adjusting pressure in the cathodes, by virtue of control over the pump, 18 along with adjusting hydrogen pressure within the hydrogen system 16.
• the pressure sensor 46 and orifice 47 comprise means for indicating to the controller 39 that there is excessive flow of gas through the vent, resulting from excessive ingestion of gas into the coolant within the coolant channels 13.
• a coolant fill pump 51 may be utilized together with a control valve 52 in order to assist in refilling coolant channels if they are drained emanating from the coolant channels through the vent 82 so as to prevent freezing in cold climates.
• a fuel cell power plant 60 includes a fuel cell stack 61 having anodes 62, cathodes 63 and coolant channels 64.
• a conventional hydrogen system 67 may provide relatively pure hydrogen or hydrogen-rich reformate gas to the anode 62. The nature of the hydrogen system 67 does not affect the present invention.
• the fuel cell power plant 60 depicted in Fig. 2 is the type described in U.S. patent application Serial No. 11/230,066 which employs evaporative cooling.
• Water is supplied to the coolant channels 64 from the liquid outlet 70 of a gas liquid separator 71, the gas outlet of which goes to exhaust (such as ambient) 72.
• the liquid flows through a connection 75 to a coolant inlet manifold 76, through the coolant channels 64, and into a gas liquid separator 77 at the outlets 80 of the coolant channels.
• the liquid outlet 79 of the separator goes to exhaust.
• the gas outlet 82 of the separator is connected to a pressure sensor 83 and through an orifice 84 to exhaust (such as ambient).
• the coolant comes from evaporation of water from the cathode exhaust.
• the cathodes are fed air which is pumped by a pump 90 draws air through a filter 91 from ambient and feeds the air through the cathodes, the exhaust being applied by a conduit 94 to a condenser 95 which is cooled by a rotating fan 96.
• the condensate goes from the condenser outlet over a conduit 99 to the gas/liquid separator 71.
• the separated water leaves the exit 70, as described hereinbefore and flows over the conduit 75 to the coolant inlet manifold 76.
• the coolant inlet manifold 76 may comprise wicking, as is described in the aforementioned application; or it may simply comprise a manifold to interconnect all of the coolant channels with the water flow. As described in the aforementioned application, the amount of water in the system may be controlled with an overflow at a suitable point.
• the pressure sensor 83 and orifice 84 sense, by means of pressure in this case, excessive flow of gas emanating from the coolant channels through the vent 82 and therefore excessive ingestion of gas into the coolant channels.
• the controller 102 may take various steps in order to prevent irreversible damage to the fuel cells in the stack 61, as described with respect to Fig. 1 hereinbefore.

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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)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (2)

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Cited By (2)

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Citations (5)

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• 2005
  • 2005-12-30 US US12/086,947 patent/US20100167140A1/en not_active Abandoned
  • 2005-12-30 WO PCT/US2005/047567 patent/WO2007086827A2/en not_active Ceased
  • 2005-12-30 JP JP2008548486A patent/JP2009522723A/ja active Pending
  • 2005-12-30 EP EP05858765.0A patent/EP1977470B1/en not_active Expired - Lifetime
  • 2005-12-30 CN CNA2005800524148A patent/CN101346843A/zh active Pending

Patent Citations (5)

Non-Patent Citations (1)

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