WO2009120170A1 - Pem fuel cell system with a heatable porous hydrophobic vent assembly wherein gas flow blockage is prevented - Google Patents

Pem fuel cell system with a heatable porous hydrophobic vent assembly wherein gas flow blockage is prevented Download PDF

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Publication number
WO2009120170A1
WO2009120170A1 PCT/US2008/004188 US2008004188W WO2009120170A1 WO 2009120170 A1 WO2009120170 A1 WO 2009120170A1 US 2008004188 W US2008004188 W US 2008004188W WO 2009120170 A1 WO2009120170 A1 WO 2009120170A1
Authority
WO
WIPO (PCT)
Prior art keywords
coolant
power plant
porous member
flow field
heating mechanism
Prior art date
Application number
PCT/US2008/004188
Other languages
French (fr)
Inventor
Robert M. Darling
Paravastu Badrinarayanan
Original Assignee
Utc Power Corp.
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 Corp. filed Critical Utc Power Corp.
Priority to PCT/US2008/004188 priority Critical patent/WO2009120170A1/en
Publication of WO2009120170A1 publication Critical patent/WO2009120170A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04007—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
    • H01M8/04298—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
    • H01M8/04—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
    • H01M8/04037—Electrical heating
    • 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
    • H01M8/04—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
    • 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
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • 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 to a polymer electrolyte membrane (PEM) fuel cell power plant which is cooled evaporatively by a water coolant system. More particularly, this disclosure relates to a coolant system of the character described which utilizes a hydrophobic porous member for maintaining coolant back pressure in the coolant flow field of the system and a porous member heater mechanism for preventing gas flow blockage of the porous member.
  • PEM polymer electrolyte membrane
  • Polymer electrolyte membrane fuel cell assemblies are relatively low temperature low operating pressure fuel cell assemblies that utilize a catalyzed polymer membrane electrolyte to process air and a hydrogen-rich fuel to produce electricity and water.
  • PEM fuel cells are well suited for use in mobile applications such as automobiles, buses, and the like, because they are relatively compact, light in weight and operate at essentially ambient pressure.
  • These types of fuel cells can be cooled by means of a water coolant which can be in a state in the power plant where liquid water does not leave the coolant flow field during normal operation.
  • a water coolant which can be in a state in the power plant where liquid water does not leave the coolant flow field during normal operation.
  • water will pass from a coolant flow field through porous plate components of the cells and through the electrolyte membrane where it will evaporate in the active area of the cells. The water thus keeps the cells moist and also cools the cells.
  • gases such as air and fuel can also pass through the porous plates into the coolant flow field. It is desirable to remove the transferred air and fuel from the water coolant so that the coolant will not be diluted and its cooling capability and its ability to prevent the porous bodies in the cell from drying out will not be degraded.
  • the transferred air and fuel removal operation should be performed while preventing the coolant water from escaping from the coolant flow field as a liquid.
  • This disclosure relates to a PEM fuel cell power plant having hydrophobic porous member components which are able to remove transferred gas from the coolant flow fields without removing water from the coolant flow fields.
  • the members ensure the maintenance of proper pressure whereby gases in the coolant flow fields will be purged therefrom through the members, while liquid coolant will be prevented from transporting into and through the members from the coolant flow fields.
  • the porous members are heated during and after operation of the power plant so as to prevent water from clogging the porous members when the power plant is not operating.
  • the fuel cell power plant includes a conventional catalyzed polymer membrane electrode having an anode side which receives a hydrogen-rich fuel stream and a cathode side which receives an oxygen-containing reactant stream.
  • a cooling flow field is disposed in heat exchange relationship with the cathode or anode side so as to cool the fuel cell during operation thereof.
  • the coolant in the cooling flow field does not circulate through the fuel cell assembly as a liquid and the cooling is accomplished by evaporation of the coolant into the air stream in the cathode flow field. Air and other gases which may transfer into the water in the coolant flow field are purged from the water coolant in the coolant flow field through the porous members which pass the gases there through.
  • Plugging of the porous members by the coolant water during power plant shutdown is prevented by heating the porous members after the power plant has been shut down. Heating of the members evaporates any coolant liquid films on or in the members.
  • the heating of the members can be can be performed by an heater which is powered by a battery after shutdown of the power plant. The heater can be left on after plant shutdown for a period of five minutes or so, so as to ensure evaporation of any liquid water which may reside in the porous plug after shutdown.
  • FIG. 1 is a schematic view of a portion of a PEM fuel cell assembly which is used in a power plant formed in accordance with this disclosure.
  • FIG. 2 is a fragmented axial sectional view of a gas exhaust line which has a hydrophobic porous member positioned therein for use in the fuel cell assembly of FIG. 1.
  • FIG. 1 is a schematic view of a portion of a PEM cell operating system, denoted generally by the numeral 2, of a fuel cell power plant formed in accordance with this disclosure.
  • the fuel cell 4 includes a catalyzed polymer electrolyte membrane 6 which is interposed between a fuel reactant flow field 8 (the anode side) and an oxidant reactant flow field 10 (the cathode side).
  • a coolant flow field 12 is disposed adjacent to the anode or cathode side 8 or 10 of the fuel cell 4.
  • the coolant flow field 12 contains a non-circulating liquid coolant, preferably water, that serves to evaporatively cool the active area of the PEM cell subassembly 2 so as to maintain the proper operating temperature of the fuel cell 4.
  • the coolant flow field 12 is of conventional construction for evaporative cooling of the anode or cathode side of the fuel cell 4 and to hydrate the catalyst membrane.
  • the coolant flow field 12 includes a coolant channel or channels (which can be formed in either an anode or cathode flow field porous plate) through which the coolant passes from an inlet end to an outlet end of the coolant flow field 12.
  • the innermost wall of the coolant flow field 12 is formed from one wall of the anode side 8 or cathode side 10 of the fuel cell 4 and is formed from a porous material so that coolant water can pass through the porous wall into the fuel or air stream in the anode or cathode side of the fuel cell 4.
  • the coolant water that passes into the air stream will vaporize in the air stream thus cooling the cell 4.
  • fuel or air from the anode and/or cathode of the cell will transfer into the water coolant in the coolant flow field.
  • the hydrogen in the fuel and the oxygen in the air are converted to protons, electrons and water.
  • the reaction product water is formed in the air stream in the cathode side 10 of the cell 4 and is removed, along with residual air and the evaporated coolant water, as cathode effluent through a line 14.
  • the coolant flow field 12 is kept under a slightly lower pressure than fuel and air by an optional vacuum pump 32 at its outlet end which pump 32 is connected to the coolant flow field 12 through a line 30.
  • the pressure differential can be created by a compressor in the air inlet line of the assembly 2 in combination with a pressure regulation valve (not shown) downstream of the stack's air exhaust, preferable downstream of the condenser, plus a pressure regulation valve (not shown) in the fuel exhaust.
  • a porous member 28 which is at least partially hydrophobic, is disposed in the line 30 as shown in FIG. 2.
  • the vacuum pump 32 if utilized, will draw any gases, such as air and/or hydrogen, which may be present in the coolant flow field 12 out of the coolant flow field 12 through the porous member 28.
  • the pores and the thickness of the member 28 are sized so as to allow passage of gases through the member 28 but prevent passage of the coolant liquid there through. Gases drawn out of the coolant flow field 12 are then vented to the ambient surroundings.
  • the porous member 28 can be made at least partially from an open weave Teflon or the like hydrophobic material to prevent the passage of liquid water.
  • the hydrophobic porous vent member 28 is shown positioned in the outlet end of the coolant flow field.
  • a highly porous metal member 29 is positioned downstream of the vent member 28 to support the member 28 and keep it in position during operation of the assembly 2.
  • the air which passes through the member 28 and into the line 30 will be hot and will be saturated with water vapor.
  • a heating device 34 operatively associated with the member 28 so that the device 34 can be activated to periodically or continuously heat the member 28 so as to prevent the coolant from forming a liquid sheet either on or in the member 28 which would block gas flow through the member 28.
  • the electrical energy needed to power the heater can come from the fuel cell system during operation of the power plant and from an auxiliary battery 36 after the power plant is shut down.
  • the battery 36 will power the heater 34 for a predetermined period of time after the power plant is shut down so that should any water enter the porous member 28, that water will be boiled off after the power plant is shut down.
  • the battery 36 can be connected to the heater 34 by a line 38 which can be interrupted by a timed switch 40 after a predetermined period of time subsequent to shut down. That time period could be five minutes, for example, or whatever period of time is found to be operative to accomplish the intended function of driving any accumulated water out of the member 28.

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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

A polymer electrolyte membrane (PEM) fuel cell power plant is cooled evaporatively by a water coolant system. The coolant system utilizes a hydrophobic porous member for venting gases such as fuel and/or air from a coolant water flow field in the system. Coolant water is prevented from clogging the porous member by heating the hydrophobic porous member after operation of the power plant for a period of time needed to drive off any liquid coolant which may have condensed in the porous member.

Description

Description
PEM FUEL CELL SYSTEM WITH A HEATABLE POROUS HYDROPHOBIC VENT ASSEMBLY WHEREIN GAS FLOW BLOCKAGE IS PREVENTED
Technical Field
[0®0H] The present disclosure relates to a polymer electrolyte membrane (PEM) fuel cell power plant which is cooled evaporatively by a water coolant system. More particularly, this disclosure relates to a coolant system of the character described which utilizes a hydrophobic porous member for maintaining coolant back pressure in the coolant flow field of the system and a porous member heater mechanism for preventing gas flow blockage of the porous member.
Background of the Disclosure
[0002] Polymer electrolyte membrane fuel cell assemblies are relatively low temperature low operating pressure fuel cell assemblies that utilize a catalyzed polymer membrane electrolyte to process air and a hydrogen-rich fuel to produce electricity and water. PEM fuel cells are well suited for use in mobile applications such as automobiles, buses, and the like, because they are relatively compact, light in weight and operate at essentially ambient pressure.
[0003] These types of fuel cells can be cooled by means of a water coolant which can be in a state in the power plant where liquid water does not leave the coolant flow field during normal operation. During the cooling operation, water will pass from a coolant flow field through porous plate components of the cells and through the electrolyte membrane where it will evaporate in the active area of the cells. The water thus keeps the cells moist and also cools the cells. During the cooling operation, gases such as air and fuel can also pass through the porous plates into the coolant flow field. It is desirable to remove the transferred air and fuel from the water coolant so that the coolant will not be diluted and its cooling capability and its ability to prevent the porous bodies in the cell from drying out will not be degraded. The transferred air and fuel removal operation should be performed while preventing the coolant water from escaping from the coolant flow field as a liquid.
We have devised a gas venting assembly and method for effectively removing the transferred air and fuel from the coolant while maintaining a proper pressure in the coolant flow field and preventing the water coolant from escaping from the coolant flow field as a liquid when not desired. Our structure and method also prevents water from plugging the venting structure during and after operation of the power plant.
Summary
[QCW5] This disclosure relates to a PEM fuel cell power plant having hydrophobic porous member components which are able to remove transferred gas from the coolant flow fields without removing water from the coolant flow fields. The members ensure the maintenance of proper pressure whereby gases in the coolant flow fields will be purged therefrom through the members, while liquid coolant will be prevented from transporting into and through the members from the coolant flow fields. The porous members are heated during and after operation of the power plant so as to prevent water from clogging the porous members when the power plant is not operating.
jprøS] The fuel cell power plant includes a conventional catalyzed polymer membrane electrode having an anode side which receives a hydrogen-rich fuel stream and a cathode side which receives an oxygen-containing reactant stream. A cooling flow field is disposed in heat exchange relationship with the cathode or anode side so as to cool the fuel cell during operation thereof. The coolant in the cooling flow field does not circulate through the fuel cell assembly as a liquid and the cooling is accomplished by evaporation of the coolant into the air stream in the cathode flow field. Air and other gases which may transfer into the water in the coolant flow field are purged from the water coolant in the coolant flow field through the porous members which pass the gases there through. Plugging of the porous members by the coolant water during power plant shutdown is prevented by heating the porous members after the power plant has been shut down. Heating of the members evaporates any coolant liquid films on or in the members. The heating of the members can be can be performed by an heater which is powered by a battery after shutdown of the power plant. The heater can be left on after plant shutdown for a period of five minutes or so, so as to ensure evaporation of any liquid water which may reside in the porous plug after shutdown.
Brief Description of the Drawings
[0007] Certain aspects and advantages of this disclosure will become more readily apparent to one skilled in the art from the following detailed description of a preferred embodiment of the disclosure when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view of a portion of a PEM fuel cell assembly which is used in a power plant formed in accordance with this disclosure; and
FIG. 2 is a fragmented axial sectional view of a gas exhaust line which has a hydrophobic porous member positioned therein for use in the fuel cell assembly of FIG. 1.
Detailed Description of the Disclosure
[MO©] Referring now to the drawings, FIG. 1 is a schematic view of a portion of a PEM cell operating system, denoted generally by the numeral 2, of a fuel cell power plant formed in accordance with this disclosure. The fuel cell 4 includes a catalyzed polymer electrolyte membrane 6 which is interposed between a fuel reactant flow field 8 (the anode side) and an oxidant reactant flow field 10 (the cathode side). A coolant flow field 12 is disposed adjacent to the anode or cathode side 8 or 10 of the fuel cell 4. The coolant flow field 12 contains a non-circulating liquid coolant, preferably water, that serves to evaporatively cool the active area of the PEM cell subassembly 2 so as to maintain the proper operating temperature of the fuel cell 4. The coolant flow field 12 is of conventional construction for evaporative cooling of the anode or cathode side of the fuel cell 4 and to hydrate the catalyst membrane. The coolant flow field 12 includes a coolant channel or channels (which can be formed in either an anode or cathode flow field porous plate) through which the coolant passes from an inlet end to an outlet end of the coolant flow field 12. The innermost wall of the coolant flow field 12 is formed from one wall of the anode side 8 or cathode side 10 of the fuel cell 4 and is formed from a porous material so that coolant water can pass through the porous wall into the fuel or air stream in the anode or cathode side of the fuel cell 4. The coolant water that passes into the air stream will vaporize in the air stream thus cooling the cell 4. At the same time, fuel or air from the anode and/or cathode of the cell will transfer into the water coolant in the coolant flow field.
|0009] During the reaction, the hydrogen in the fuel and the oxygen in the air are converted to protons, electrons and water. The reaction product water is formed in the air stream in the cathode side 10 of the cell 4 and is removed, along with residual air and the evaporated coolant water, as cathode effluent through a line 14. The coolant flow field 12 is kept under a slightly lower pressure than fuel and air by an optional vacuum pump 32 at its outlet end which pump 32 is connected to the coolant flow field 12 through a line 30. Alternatively, the pressure differential can be created by a compressor in the air inlet line of the assembly 2 in combination with a pressure regulation valve (not shown) downstream of the stack's air exhaust, preferable downstream of the condenser, plus a pressure regulation valve (not shown) in the fuel exhaust. A porous member 28 which is at least partially hydrophobic, is disposed in the line 30 as shown in FIG. 2. The vacuum pump 32, if utilized, will draw any gases, such as air and/or hydrogen, which may be present in the coolant flow field 12 out of the coolant flow field 12 through the porous member 28. The pores and the thickness of the member 28 are sized so as to allow passage of gases through the member 28 but prevent passage of the coolant liquid there through. Gases drawn out of the coolant flow field 12 are then vented to the ambient surroundings. The porous member 28 can be made at least partially from an open weave Teflon or the like hydrophobic material to prevent the passage of liquid water.
[0011 ©J Referring now to FIG. 2, the hydrophobic porous vent member 28 is shown positioned in the outlet end of the coolant flow field. A highly porous metal member 29 is positioned downstream of the vent member 28 to support the member 28 and keep it in position during operation of the assembly 2. The air which passes through the member 28 and into the line 30 will be hot and will be saturated with water vapor. Thus, there is a possibility that water may condense and block the porous member 28 and interfere with gases passing through the member 28. This problem is avoided by having a heating device 34 operatively associated with the member 28 so that the device 34 can be activated to periodically or continuously heat the member 28 so as to prevent the coolant from forming a liquid sheet either on or in the member 28 which would block gas flow through the member 28. These heating devices are commercially available. The electrical energy needed to power the heater can come from the fuel cell system during operation of the power plant and from an auxiliary battery 36 after the power plant is shut down. The battery 36 will power the heater 34 for a predetermined period of time after the power plant is shut down so that should any water enter the porous member 28, that water will be boiled off after the power plant is shut down. The battery 36 can be connected to the heater 34 by a line 38 which can be interrupted by a timed switch 40 after a predetermined period of time subsequent to shut down. That time period could be five minutes, for example, or whatever period of time is found to be operative to accomplish the intended function of driving any accumulated water out of the member 28.
It will be readily appreciated that the system of this disclosure will ensure proper removal of gases from the coolant stream while avoiding the problem of liquid blockage of the gas venting member in the system.
[00112] Since many changes and variations of the disclosed embodiment of the disclosure may be made without departing from the inventive concept, it is not intended to limit the disclosure otherwise than as required by the appended claims.

Claims

Claims What is claimed is:
1. In a fuel cell power plant assembly containing a plurality of fuel cells, a coolant system containing an aqueous coolant for controlling the operating temperature of the fuel cells, said coolant system comprising: a) a coolant flow field adjacent to each of said cells; b) a venting system for venting gases from said coolant flow field during operation of said power plant; c) a porous member disposed in said venting system for allowing passage of gases while maintaining exit pressure in said coolant flow field; and d) a heating mechanism operatively associated with said porous member for heating said porous member thereby preventing gas flow blockage in said porous member by said aqueous liquid coolant, said heating mechanism being operational after shutdown of said power plant.
2. The power plant assembly of Claim 1 wherein said porous member is hydrophobic.
3. The power plant assembly of Claim 1 wherein said heating mechanism is powered by a battery after said power plant is shut down, and is operative to remove any of said liquid coolant in or on said porous member after shutdown of said power plant, said battery being connected to said heating mechanism.
4. The power plant assembly of Claim 3 further including a switch which is selectively operable to disconnect said battery from said heating mechanism at a predetermined time after shutdown of said power plant.
5. A method for venting gases from a coolant system containing an aqueous coolant in a fuel cell power plant assembly coolant flow field, said method comprising: a) the step of venting said gases from said coolant flow field through a porous member disposed in a venting system operative to allow passage of said gases while maintaining exit pressure in said coolant flow field; and b) the step of heating said porous member with a heating mechanism which is operatively associated with said porous member so as to prevent gas flow blockage in said porous plug by said aqueous liquid coolant; and c) the step of operating said heating mechanism after shutdown of said power plant so as to remove any liquid coolant which may have accumulated in said porous member.
6. The method of Claim 5 comprising the step of powering said heating mechanism with a battery during shutdown of said power plant.
7. The method of Claim 6 comprising the step of disconnecting said heating mechanism from said battery at a predetermined time period after said power plant is shut down.
8. The method of Claim 5 wherein said porous member is hydrophobic.
PCT/US2008/004188 2008-03-28 2008-03-28 Pem fuel cell system with a heatable porous hydrophobic vent assembly wherein gas flow blockage is prevented WO2009120170A1 (en)

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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2008/004188 WO2009120170A1 (en) 2008-03-28 2008-03-28 Pem fuel cell system with a heatable porous hydrophobic vent assembly wherein gas flow blockage is prevented

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006164903A (en) * 2004-12-10 2006-06-22 Nissan Motor Co Ltd Fuel cell and control method therefor
US20070160883A1 (en) * 2006-01-06 2007-07-12 Robert Darling Fuel cell system with a porous hydrophobic plug for maintaining system back pressure and methods for designing the plug and for designing systems for using the plug

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006164903A (en) * 2004-12-10 2006-06-22 Nissan Motor Co Ltd Fuel cell and control method therefor
US20070160883A1 (en) * 2006-01-06 2007-07-12 Robert Darling Fuel cell system with a porous hydrophobic plug for maintaining system back pressure and methods for designing the plug and for designing systems for using the plug

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