WO2010082920A1 - Liquide de refroidissement de pile à combustible - Google Patents

Liquide de refroidissement de pile à combustible Download PDF

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Publication number
WO2010082920A1
WO2010082920A1 PCT/US2009/030805 US2009030805W WO2010082920A1 WO 2010082920 A1 WO2010082920 A1 WO 2010082920A1 US 2009030805 W US2009030805 W US 2009030805W WO 2010082920 A1 WO2010082920 A1 WO 2010082920A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel cell
fluid
aqueous phase
oil phase
emulsifier
Prior art date
Application number
PCT/US2009/030805
Other languages
English (en)
Inventor
Michael L. Perry
Xiaomei Yu
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/US2009/030805 priority Critical patent/WO2010082920A1/fr
Publication of WO2010082920A1 publication Critical patent/WO2010082920A1/fr

Links

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
    • H01M8/04029—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
    • H01M8/04298—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
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04417—Pressure; Ambient pressure; Flow of the coolant
    • 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
    • H01M8/04746—Pressure; Flow
    • H01M8/04768—Pressure; Flow of the coolant
    • 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

  • This disclosure relates to a fluid for a fuel cell. More particularly, this disclosure relates to a microemulsion-based coolant for a fuel cell.
  • Fuel cell assemblies are well known. Some fuel cells include a polymer electrolyte membrane (PEM) positioned between electrodes that contain a platinum catalyst. One of the electrodes operates as an anode while the other operates as a cathode. These two electrodes and the PEM are positioned between separator plates. These separator plates commonly have anode flow fields for moving fuel adjacent to the anode and cathode flow fields on the opposite side for moving oxidant.
  • the plates are often known as bipolar plates.
  • Some PEM fuel cells utilize porous bipolar plates and other fuel cells use solid, instead of porous, bipolar plates. These bipolar plates can be made of carbon or metal. The bipolar plates often separate gas within the fuel cell. The porous plates are kept filled with liquid to minimize gas communication between the opposite sides of the plates. Both types of fuel cells typically include a gas-diffusion layer located between each electrode and the bipolar plates.
  • fuel cells generate thermal energy and liquid, typically water, byproducts.
  • Water can be used to carry the thermal byproducts away from the fuel cell, but large droplets of water can freeze and undesirably bind or interfere with fuel cell components within the fuel cell. Accordingly, water is often mixed with, or replaced by, another type of fluid.
  • Some of these fluids, such as ethylene glycol are miscible with water, which is advantageous since water has many advantages as a coolant, e.g., it has a relatively large heat capacity, is inexpensive, and plentiful.
  • these other miscible fluids often undesirably react with the fuel cell electrodes.
  • the coolant is commonly circulated through the interior of the some, or all, of the bipolar plates to manage the operating temperature of the cells.
  • the coolant can also be used to manage the liquid water present within the cells since the coolant is in communication with the electrodes through the pores in the porous plates.
  • United States Patent No. 5,700,595 discloses that such a water management function has many advantages.
  • the solid plate ordinarily blocks coolant from contacting the electrode, but leaks can develop. What is needed is a coolant that does not undesirably react with the fuel cell electrodes, provides thermal management, and facilitates water management.
  • An example fuel cell fluid includes an oil phase and an emulsifier associated with the oil phase.
  • the emulsifier is for forming a microemulsion with an aqueous phase and the oil phase.
  • the oil phase carries the aqueous phase in the microemulsion as the oil phase moves within a fuel cell.
  • An example device for removing byproducts from a fuel cell includes a valve configured to regulate flow of a fuel cell fluid to a fuel cell and a controller configured to control the valve to adjust the flow of the fuel cell fluid.
  • the fuel cell fluid contains an emulsifier for forming a microemulsion that contains a fuel cell byproduct.
  • An example method of removing byproducts from a fuel cell includes the steps of joining an aqueous phase fluid to an oil phase fluid to create a microemulsified fluid and moving the aqueous phase fluid away from a fuel cell using the microemulsified fluid
  • Figure 1 is a partial schematic illustrating an example device designed according to an embodiment of this invention.
  • Figure 2 is a schematic view of an example coolant fluid.
  • Figure 3 is a partial schematic illustrating another example device designed according to an embodiment of this invention.
  • an example fuel cell device 10 includes a fuel cell stack assembly (CSA) 12, a controller 14, and a coolant supply 16.
  • the coolant 20 one type of fuel cell fluid, moves from the coolant supply 16 through a valve/pump 18 to the CSA 12 and then moves away from the CSA 12 to carry byproducts away from the CSA 12.
  • the controller 14 controls the valve/pump 18 to adjust flow of the coolant 20 between the coolant supply 16 and the CSA 12.
  • the example coolant 20 is a water-in-oil microemulsion. That is, the coolant 20 includes an emulsifier 38 joining an aqueous phase fluid 42 to an oil phase fluid 46. Joining the aqueous phase fluid 42 to the oil phase fluid 46 with the emulsifier 38 allows the oil phase fluid 46 to carry the aqueous phase fluid 42. The aqueous phase fluid 42 joined to the oil phase fluid 46 forms a swollen micelle 50.
  • the example coolant 20 carries liquid and thermal byproducts away from the CSA 12.
  • the example coolant 20 also manages the liquid byproducts within the CSA 12.
  • the coolant 20 moves the byproducts from the CSA 12 to a radiator 32 from the CSA 12.
  • the coolant 20 releases some of the thermal byproducts (i.e., heat) from the radiator 32 to the surrounding environment at a hot ambient air exhaust 34.
  • a fan 40 moves air across the radiator 32 to enhance the transfer of thermal byproducts.
  • the example CSA 12 produces fluid and thermal byproducts.
  • water a type of fluid byproduct, beneficially absorbs thermal byproducts within the CSA 12. If large droplets of water are present in cold conditions, the large water droplets can undesirably bind or freeze components of the CSA 12.
  • the microemulsified coolant 20 in this example includes droplets of the aqueous phase fluid 42 (e.g., water) distributed throughout the oil phase fluid 46 relatively evenly, which limits the size of droplets of the aqueous phase fluid 42. The smaller droplets in the microemulsion cannot combine and form larger droplets.
  • the frozen droplets are so small that they will provide little interference to the overall operation of the CSA 12.
  • the aqueous phase fluid 42 was free to form larger droplets, which could hamper operation of the CSA 12 when frozen.
  • the example aqueous phase fluid 42 is primarily water and may contain additives, trace impurities, etc. Some example additives include rust inhibitors, oxidative inhibitors, or anti-wear agents.
  • the oil phase fluid 46 is chosen to be electrochemically inert such that it will not interfere with normal cell operation if it is exposed to the electrodes. An example of such an oil phase would be a hydrofloruroether.
  • the coolant 20 flowing to the CSA 12 from the valve 18 contains each of the emulsifier 38, the aqueous phase fluid 42, and the oil phase fluid 46.
  • the coolant 20 may collect additional aqueous phase fluid 42 (i.e., liquid water byproducts) within the CSA 12.
  • Other examples may move only the emulsif ⁇ er 38 and the oil phase fluid 46 to the CSA 12 in the coolant 20, a type of solution.
  • the liquid byproducts of the CSA 12 provide all of the aqueous phase fluid 42 for the microemulsion. That is, the microemulsion forms entirely within the CSA 12.
  • the valve/pump 18 is controlled in one example to adjust the specific mix of the emulsifier 38, the aqueous phase fluid 42, and the oil phase fluid 46 in the coolant 20 flowing to the CSA 12.
  • the emulsifier 38 is characterized by its ability to form a microemulsion with the aqueous phase fluid 42 and oil phase fluid 46.
  • One example emulsifier 38 is nonionic.
  • Other examples are anionic, cationic, or amphoteric.
  • the nonionic examples are often less conductive than ionic examples.
  • the emulsifier 38 is a polymer having a plurality of hydrophobic moieties, (e.g., hydrocarbon chains).
  • the emulsifier is a polymer having a plurality of hydrophilic moieties, (e.g., side chains ending with sulfonate or carbonate groups).
  • the emulsifier 38 has an affinity for the carbon surfaces within the CSA 12, which can enhance the movement of the aqueous phase fluid 42 through the CSA 12.
  • Microemulsions are known, and a person skilled in the art with the benefit of this disclosure would understand how to select the emulsifier 38.
  • microemulsions which are sometime referred to micellar solutions, are typically clear, bright, and transparent, as the swollen micelle 50 is smaller than the wave length of visible light, or less than 0.1 micron in this example. Thus, there is little or no perceivable diffraction of light through the swollen micelle 50.
  • Microemulsions are also characterized by their relatively long term storage stability. That is, microemulsions are often able to maintain a single phase at ambient temperatures, whereas macroemulsions, or other types of emulsions, tend to separate over time at ambient temperatures.
  • the CSA 12 typically includes a plurality of cells as is known. Reactions within the CSA 12 utilize the oxygen within the air.
  • the CSA 12 receives hydrogen from a fuel supply 62 at a fuel flow field 66 that is positioned adjacent to the anode 70, which typically consists of multiple layers, such as a gas diffusion layer and a catalyst layer, adjacent to a polymer electrolyte membrane (PEM) 74.
  • PEM polymer electrolyte membrane
  • Electrons from the hydrogen move from the anode 70 along an external circuit 78 to perform useful work and then to a cathode 68 positioned between an oxidant flow field 64 and the PEM layer 74.
  • the cathode 68 typically consists of multiple layers such as a gas diffusion layer and a catalyst layer. Protons pass directly through the PEM layer 74 to the cathode 68 where they react with the oxygen and electrons.
  • An air exhaust 98 communicates air from the CSA 12 directly to the surrounding atmosphere at 100.
  • the example CSA 12 is a porous plate type fuel cell and permits water movement though the porous plate.
  • the coolant 20 is introduced to the CSA 12 at 90 and exits at 94 to remove thermal energy from the CSA 12.
  • Managing the water 86 includes removing water from the CSA 12, redistributing water 86 within the coolant 20, and introducing water at the coolant inlet of the stack 90, or some combination of those.
  • the emulsifier 38 joins the water 86 to the oil phase fluid 46 of the coolant 20.
  • the coolant 20 exiting the CSA 12 at 94 may thus contain more water 86 than the coolant 20 entering the CSA 12 at 90 because the emulsifier 38 joins some of the water 86 to the oil phase fluid 46 within the CSA 12.
  • some of the byproduct water exits the CSA 12 as vapor at a fuel exhaust 97 separate from the coolant 20 and moves directly into the surrounding atmosphere at 104.
  • the coolant 20 After absorbing sufficient water 86, the coolant 20 becomes saturated. That is, there are insufficient available emulsif ⁇ ers remaining in the coolant 20 that are able to join water 86 to the oil phase fluid 46 once a certain level of microemulsif ⁇ cation occurs. As known, such saturated solutions develop characteristics of a two-phase solution, such as visible separation between the oil phase fluid 46 and the water 86, a cloudier solution, and a higher viscosity.
  • the saturation point is also known as the cloud-point of the coolant 20.
  • the cloud-point is used as a visual cue for the controller 14 to adjust the amount coolant 20 flow to the CSA 12 and allow the stack temperature to rise slightly, which will result in more water vapor exiting the stack in stream 98.
  • the temperature of the radiator 32 is increased (e.g., by decreasing the radiator fan speed) to lessen the amount of liquid cooling provided by the circulating coolant 20.
  • the air exhaust at 98 moves from the device 10 through a condenser 102.
  • the coolant 20 introduced to the device 10 at 90 provides the aqueous phase fluid 42 that circulates within the device without going through a heat exchanger, unlike the device depicted in Fig. 1.
  • Thermal energy within the CSA 12 changes the state of the aqueous phase fluid 42 to a vapor.
  • the condenser 102 then condenses the vapor and returns the aqueous phase fluid 42 to the coolant 20 at 106.
  • a fan 40 moves air across the condenser 102 to enhance the amount of water condensed from the air exhaust stream 98. Air within the condenser 102 from the air exhaust 98 moves to the surrounding environment at 103.
  • Example features of the fuel cell device 10 include that the coolant 20 provides an anti-freeze solution that is miscible with water, but does not act as a poison to the CSA 12.
  • the example oil phase fluid 46 has desirable heat-transfer fluid characteristics (e.g., relatively high heat capacity and low viscosity in the temperature range of interest) and is electrochemically inert. A combination of emulsif ⁇ ers can be employed to form the desired emulsif ⁇ er 38 within coolant 20. If the aqueous phase fluid 42 in the coolant 20 is insufficient to manage the byproducts of the CSA 12 then the coolant 20 can be designed to have a cloud-point temperature near, or just below, the operating temperature of the stack (e.g., ⁇ 65 C). The oil phase fluid 46 remains a liquid at all temperatures of interest (e.g., from -40 C to +90 C).
  • FIG. 10 Further features of the example fuel cell device 10 are providing water minimization (especially free water that readily freezes below 0 C), reducing issues associated with free water, compatibility with sensibly-cooled or evaporatively-cooled systems, providing a simpler system than previous multi-component fluid systems such as immiscible coolant concepts since the coolant 20 is essentially a single phase (e.g., minimal separation/mixing devices), and that the fuel cell device 10 does not require two different start-up modes of operation (e.g., frozen-state and normal operation), since the same coolant 20 is circulated through the CSA 12 under all start conditions.
  • FIG. 12 Although a preferred embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

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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

Un fluide exemplaire de pile à combustible comprend une phase huileuse et un émulsifiant associé à la phase huileuse. L'émulsifiant est conçu pour former une micro-émulsion avec une phase aqueuse et la phase huileuse. La phase huileuse transporte la phase aqueuse dans la micro-émulsion qui se déplace dans la pile à combustible et fournit des fonctions de gestion thermique et aqueuse.
PCT/US2009/030805 2009-01-13 2009-01-13 Liquide de refroidissement de pile à combustible WO2010082920A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2009/030805 WO2010082920A1 (fr) 2009-01-13 2009-01-13 Liquide de refroidissement de pile à combustible

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2009/030805 WO2010082920A1 (fr) 2009-01-13 2009-01-13 Liquide de refroidissement de pile à combustible

Publications (1)

Publication Number Publication Date
WO2010082920A1 true WO2010082920A1 (fr) 2010-07-22

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PCT/US2009/030805 WO2010082920A1 (fr) 2009-01-13 2009-01-13 Liquide de refroidissement de pile à combustible

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6015634A (en) * 1998-05-19 2000-01-18 International Fuel Cells System and method of water management in the operation of a fuel cell
WO2005068581A1 (fr) * 2004-01-13 2005-07-28 Toyota Jidosha Kabushiki Kaisha Fluide de refroidissement et systeme de refroidissement
US7344655B1 (en) * 1999-09-28 2008-03-18 Toyota Jidosha Kabushiki Kaisha Coolant, method of enclosing coolant, and cooling system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6015634A (en) * 1998-05-19 2000-01-18 International Fuel Cells System and method of water management in the operation of a fuel cell
US7344655B1 (en) * 1999-09-28 2008-03-18 Toyota Jidosha Kabushiki Kaisha Coolant, method of enclosing coolant, and cooling system
WO2005068581A1 (fr) * 2004-01-13 2005-07-28 Toyota Jidosha Kabushiki Kaisha Fluide de refroidissement et systeme de refroidissement

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