WO2004091023A2 - Pile a combustible - Google Patents

Pile a combustible Download PDF

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Publication number
WO2004091023A2
WO2004091023A2 PCT/DK2004/000264 DK2004000264W WO2004091023A2 WO 2004091023 A2 WO2004091023 A2 WO 2004091023A2 DK 2004000264 W DK2004000264 W DK 2004000264W WO 2004091023 A2 WO2004091023 A2 WO 2004091023A2
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WO
WIPO (PCT)
Prior art keywords
flow plate
flow
fuel cell
cathode
anode
Prior art date
Application number
PCT/DK2004/000264
Other languages
English (en)
Other versions
WO2004091023A3 (fr
Inventor
Mads Willum
Original Assignee
Altercell Fuel Cell Technology Aps
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 Altercell Fuel Cell Technology Aps filed Critical Altercell Fuel Cell Technology Aps
Publication of WO2004091023A2 publication Critical patent/WO2004091023A2/fr
Publication of WO2004091023A3 publication Critical patent/WO2004091023A3/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
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1009—Fuel cells with solid electrolytes with one of the reactants being liquid, solid or liquid-charged
    • H01M8/1011—Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
    • 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
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • 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
    • H01M8/0247—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the form
    • 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
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/0263—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant having meandering or serpentine paths
    • 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
    • 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
    • H01M8/2455—Grouping of fuel cells, e.g. stacking of fuel cells with liquid, solid or electrolyte-charged 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
    • H01M8/24—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
    • 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 invention relates to a fuel cell system for producing electrical energy.
  • Combustion engines are widely used to power for example vehicles, but combustion engines pollute the air with combustion products and further the efficiency is relatively low.
  • Fuel cells provide a promising new technology and in recent years large efforts have been made to provide fuel cells to replace for example batteries.
  • a fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity and heat in the process. It is very much like a battery that can be recharged while drawing power from it. Instead of recharging using electricity, however, a fuel cell uses hydrogen and oxygen.
  • a fuel reactant typically methanol or hydrogen
  • an oxidising agent air or oxygen
  • the fuel cell typically comprises an anode electrode, a cathode electrode, and an electrolyte, such as an ion conducting membrane, which separates the electrodes.
  • the electrolyte is in contact with a catalytic layer acting as an anode electrocatalyst that splits the fuel into protons and electrons as a result of oxidation, releasing protons from the reactant molecule.
  • Protons generated at the anode selectively pass through the ion conducting membrane to the fuel cell cathode.
  • a second catalytic layer reduces protons with oxygen molecules to form water. Electrons generated by anodic oxidation of fuel molecules cannot pass through the ion conducting membrane and must flow around the membrane toward the cathode electrode. The flow of electrons is collected by current collection plates and directed into an electrical circuit.
  • the flow of protons (hydrogen ions) through the ion conducting membrane and the movement of electrons toward the cathode generate electrical energy in the fuel cell.
  • the fuel cell can generate electrical energy continuously and maintain a specific power output, as long as constant supplies of fuel reactant and an oxidising agent are maintained, so fuel cells can potentially run for an infinite time. Further the fuel cell runs cleanly producing water and carbon dioxide as waste product of the oxidation/reduction of the fuel.
  • a special type of fuel cell is the "direct" type, wherein the fuel is directly fed into the fuel cell without prior modification, including the so-called direct methanol fuel cell (DMFC) systems that employ methanol as the fuel reactant and incorporate an ion conducting membrane electrolyte.
  • DMFC direct methanol fuel cell
  • Membrane electrolytes are non-liquid, non-corrosive electrolytes capable of operating at low temperatures, which makes such electrolytes commercially attractive for stationary and portable electronics applications.
  • membrane electrolytes possess excellent electrochemical and mechanical stability, as well as high ionic conductivity that allow them to function as both an electrolyte and a separator.
  • MEA membrane electrode assembly
  • Prior art fuel cell systems further employ current collector plates on outer sides of the full cell unit, conducting and collecting electrons generated by the electrochemical oxidation of the fuel.
  • Current collector plates are typically constructed of carbon composites or metals, such as stainless steel and titanium, providing high electronic conductivity. These current collector plates should be impermeable to reactants and include flow fields having flow channel geometries that provide effective supplies of fuel and oxygen.
  • Fuel cells are often multi-cell stacks comprising a number of single fuel cells joined to form a cell stack to obtain sufficient power densities to meet specific electrical power requirements, as one fuel cell element provides approximately 1.2 V.
  • Common fuel cell stacks are relatively bulky, which is a disadvantage, especially for portable devices, such as mobile phones, lap-top computers, PDA's etc.
  • the size of the power unit is important in order to maintain the portability of such a device, and to incorporate the power unit in the device without rendering the device very bulky.
  • DMFC system - Direct Methanol Fuel Cell system DMFC system relates to an electro chemical mechanism where electrons are separated from H2 molecules (the preferred fuel) and thereby generating a current of electrons. This current may be used to power an electric circuit.
  • This DMFC system is preferably fuelled by a methanol/water solution that may be contained in a cartridge; this cartridge is preferably inserted in the fuel circuit of the DMFC system and once inserted the DMFC system can run for a period of time until the cartridge has been emptied. Once emptied the cartridge may easily be replaced by a new one and the DMFC system can continue to power up the electronic equipment connected to it.
  • Electrically conducting flow plate May comprise two different kinds of flow plate assemblies as described below.
  • Anode flow plate - Anode Interconnect Flow Plate Assembly A plate that preferably comprises flow channels for preferably liquid fuel such as methanol or the alike.
  • the plate may be made of a material able to conduct electrons such as metal or carbon.
  • the plates may be made out of plastic and mounted together with metallic plates (Anode interconnect plates) on the side surfaces.
  • the plates may be made of plastic material on to which a metal layer is applied to the surface of the plastic.
  • the plate may be made of a material able to conduct electrons such as metal or carbon.
  • the plates may be made of plastic material and mounted together with metallic plates (Cathode interconnect plates) on the side surfaces.
  • the plates may be made of plastic material on to which a metal layer is applied to the surface of the plastic.
  • the component conducting the electro-chemical process Preferably a solid electrolyte is separating catalysed electrodes.
  • electrolyte inside a MEA also called electrolyte membrane in this document.
  • the layer called or representing the anode in a MEA Preferably the layer called or representing the anode in a MEA. It may also be mentioned as “anode electrode” in this document Cathode
  • the layer called or representing the cathode in a MEA Preferably the layer called or representing the cathode in a MEA. It may also be mentioned as “cathode electrode” in this document.
  • anode, electrode membrane, cathode should preferably be interpreted to describe the structure of a MEA.
  • a plate for conducting electrons may preferably comprise protrusions in order to facilitate electrical connection to the MEA. Furthermore the plate may also comprise slits and flaps for directing liquid fuel such as methanol and water and preferably a mix thereof towards a surface of a MEA.
  • the anode interconnect plates are preferably mounted together with an anode flow plate.
  • a plate for conducting electrons also called cathode.
  • the plate may preferably comprise protrusions in order to facilitate connection to the MEA. Furthermore the plate may also comprise flaps for directing gas such as air towards a MEA.
  • the cathode interconnect plates are preferably mounted together wit a cathode flow plate.
  • Cathode spacer May comprise two different kinds of flow plates as described below.
  • a plate preferably comprising multiple channels for guiding air over the surface of a MEA from an inlet towards an outlet.
  • a plate preferably comprising multiple channels for guiding liquid over the surface of a MEA from an inlet towards an outlet.
  • flow plate may preferably be interpreted as describing the structure of one of the following "Cathode Interconnect Flow Plate Assembly” or "Anode Interconnect Flow Plate Assembly”.
  • flow plate occurs in-between the words cathode and GPM such as “cathode, flow plate, gas permeable membrane”
  • the words “flow plate” should preferably be understood to describe the structure of a Cathode Interconnect Flow Plate Assembly.
  • a flow plate may comprise two separated systems of flow channels.
  • End plate top and bottom
  • a plate for sealing a stack in the bottom or top, preferably applying perpendicular pressure to the components between the end plates, the stack may comprise at least one of the above-described plates.
  • Gas Permeable Membrane - GPM A membrane that enables transportation of gas from one side of the membrane to the other side of the membrane. While at the same time stopping less volatile substances such as liquids.
  • the fuel solution is preferably at least one of, or a mixture of the following examples: methanol, ethanol, hydrogen, propane etc. This is not an exhaustive list of fuels that could be used in connection with the present invention, other types of fuels not mentioned here may also be used.
  • the fuel is mixed with water so that a mixture of water and fuel enters the cell.
  • the percentage of water in the fuel solution may be between 0 to 99,9%, Such as between 99% to 95%, 94% to 90%, 89% to 85%, 84% to 80%, 79% to 70%.
  • the percentage of water is in the vicinity of 97%.
  • the percentage of water in the fuel solution is preferably possible to manipulate during operation of a fuel cell since the fuel cell may need more or less fuel depending on the load.
  • a fuel cell comprising at least one cathode electrode, at least one anode electrode, and a first flow plate defining at least one first flow channel, the first flow channel being in fluid contact with at least two electrodes of a first polarity, said first flow plate being electrically conducting, the fuel cell further comprising at least one second electrically conducting flow plate defining at least one second flow channel, the second flow channel being in fluid contact with at least two electrodes of a second polarity, the fuel cell further comprising at least one electrode membrane, each electrode membrane being in contact with an anode electrode and a cathode electrode.
  • a flow plate for a fuel cell comprising a flow channel for a fluid, the flow plate having a first and a second surface, and at least a portion of least one of the first and second surfaces is electrically conducting, characterised in that the flow plate is a sandwich construction comprising an electrically insulating core member.
  • the fuel cell may further comprise a fuel supply conduit adapted to supply fuel to at least one flow plate. In order to supply the necessary layers with fuel.
  • the fuel cell may comprise an electrode wherein the electrode is an electrochemical electrode such as a MEA.
  • the fuel cell may furthermore comprise at least one set of elements having the following order: anode, electrode membrane, cathode, flow plate, cathode, electrode membrane anode, flow plate.
  • the fuel cell may further comprise a gas permeable membrane in order to facilitate the removal of C0 2 and/or CO during operation of the fuel cell.
  • a fuel cell is provided, which is adapted to ventilate a gas trapped in the flow plate, whereby the risk of choking of the flow plate is reduced, which could reduce the efficiency of the fuel cell.
  • the gas permeable membrane is preferably adapted to allow C0 2 and/or CO to permeate while not allowing methanol and/or water to permeate.
  • C0 2 and/or CO permeate
  • methanol and/or water permeate
  • the fuel cell may preferably also comprise at least one set of elements having the following order: anode, electrode membrane, cathode, flow plate, gas permeable membrane and flow plate.
  • the gas permeable membrane preferably allows C0 2 to permeate.
  • the fuel cell may further comprise at least one electrode membrane, each electrode membrane being in contact with an anode electrode and a cathode electrode.
  • a MEA being in contact with preferably an anode interconnection plate and a cathode interconnection plate.
  • the flow plate according to the second aspect of the invention wherein the flow channel defines a flow path at least partially open on both the first and second surfaces, in order to facilitate the flow of fluid towards the surface of a MEA.
  • the flow plate may further comprise a sensor, such as a temperature sensor, arranged in the core member.
  • the sensor preferably measures different parameters related to the operation of a fuel cell. In this way it is possible to control the operation of a fuel cell more accurate.
  • the flow plate preferably comprises a electrically conducting surface portion wherein the electrically conducting surface portion may be a separate metal foil provided at the surface of the core member.
  • the surface portion may be manufactured from a material having an outstanding electrical conductivity, such as gold. As only a minimum amount of material is needed for the surface portion, the price of the material for the surface portions will not significantly increase the total price of the fuel cell, i.e. the material preferably chosen may preferably be optimised with regard to electrical conductivity.
  • the surface portion may be provided as thin sheets, or may even be provided as a surface coating of the flow plate also called core member, such as by plasma spraying, chemical vapour deposition or any other suitable method.
  • the electrically conducting surface portion may be a metal layer provided on the surface of the core member.
  • the flow plate may have edge zone of the first and/or second surfaces which preferably are substantially free of electrically conducting material.
  • the flow plate may comprise electrically conducting surfaces further comprising projecting peaks.
  • the connection between the electrically conducting surface and the MEA is more efficient.
  • the connection between the electrically conducting surface and the MEA is more efficient.
  • the flow plate may further comprise flaps for directing flow in the channel towards the first and/or second surface of a MEA or GPM.
  • the fuel cell becomes more effective since more fluid is directed towards the surface of a MEA and less fluid passes by without getting in contact with the MEA.
  • the flaps may preferably be bend so that the flaps inclines preferably up to 45 degrees angle from the flow plate.
  • the flaps may preferably comprises a second bend in order to avoid a sharp edge towards the surface of a MEA.
  • the projecting peaks may also be bumps in the flow plate. By punching one of the sides of a flow plate with a tool comprising small peaks a bumpy surface on the flow plate will be obtained. The bumps will enhance the contact between the flow plate and MEA.
  • the projecting peaks may protrude on both sides of the flow plate.
  • the flow plate may further comprise at least one slit in order to facilitate the access of a fluid towards a MEA/GPM surface.
  • the flow plate may furthermore comprise a first flow channel and a second flow channel being separated from each other.
  • the first and second flow channel is on opposite sides of the flow plate.
  • the flow plates may be manufactured in sets such as an assembly of flow plates comprising at least two flow plates and at least two interconnect plates wherein the plates are connected by metal connections.
  • the present invention relates to a fuel cell comprising: at least one cathode electrode, at least one anode electrode, and a first flow plate defining at least one first flow channel, the first flow channel being in fluid contact with at least two electrodes of a first polarity and wherein the first flow plate is electrically conducting.
  • Any flow channel according to any aspect of the present invention may have a first side and a second side, each of said sides being adapted to be in fluid contact with an element.
  • a third embodiment of the present invention may comprise at least one second electrically conducting flow plate defining at least one second flow channel, the second flow channel being in fluid contact with at least two electrodes of a second polarity.
  • the order of elements may be: anode, electrode membrane, cathode, flow plate, cathode, electrode membrane anode, flow plate etc.
  • the first and any other aspect of the present invention may comprise a fuel supply conduit adapted to supply fuel to at least one flow plate.
  • the electrode may be an electrochemical electrode.
  • the first and any other aspect of the present invention may comprise at least one electrode membrane, each electrode membrane being in contact with an anode electrode and a cathode electrode.
  • the present invention may relate to a fuel cell comprising at least one set of elements having the following order: anode, electrode membrane, cathode, flow plate, cathode, electrode membrane, anode, flow plate.
  • the anode side of 2 MEAs eventually may be facing the dedicated anode interconnect flow field plate; the cathode side can eventually also be build up similar to the anode side, i.e. the cathode side of 2 MEAs is facing the dedicated cathode flow plate, see figure 2.
  • the anode interconnect flow field plate may be in direct contact with two MEAs.
  • the cathode interconnect flow field plate may be in direct contact with two MEAs.
  • the individual anode and cathode interconnect flow plates may be designed so they are in direct contact with the corresponding MEA surface, i.e. anode or cathode surface; this allows for example one anode interconnect flow plate to have direct contact with 2 MEAs instead of one as it is in the "serie" design. It is the same with a cathode interconnect flow plate. Thus one flow plate may be in direct contact with 2 MEAs, see figure 2.
  • the present invention relates to a fuel cell comprising : at least one cathode electrode, at least one anode electrode, and at least one flow plate being in fluid contact with a first electrode of a first polarity and a gas permeable membrane.
  • gas permeable membrane may be adapted to allow C0 2 to permeate while not allowing methanol and/or water to permeate.
  • One of the MEAs in contact with the anode interconnect flow plate can be replaced with a gas permeation membrane, i.e. a membrane allowing the C0 2 bubbles or molecules to permeate through but still keeping the methanol/water solution inside the anode flow field.
  • a gas permeation membrane i.e. a membrane allowing the C0 2 bubbles or molecules to permeate through but still keeping the methanol/water solution inside the anode flow field.
  • the electrons may be lead from the anode to the cathode plate via a cable connection see e.g. figures 23 and 24.
  • the parallel stack design allows one to design a stack where for example a multitude of XX anode and cathode flow plates are connected in parallel and thereby raising the current to a certain level and still having the voltage on relatively low level, see figures 3, 15 and 18.
  • the present invention may relate to a fuel cell comprising at least one set of elements having the following order: anode, electrode membrane (MEA), cathode, flow plate, gas permeable membrane and flow plate.
  • MEA electrode membrane
  • flow plate gas permeable membrane
  • a major advantage of the present invention is that the overall height/length of the stack is reduced compared to a similar "serial" connected stack; when the height/length is reduced the weight is of course also reduced.
  • Another advantage is that the production costs is also reduced.
  • the parallel and #3 stack design uses an integrated "bus bar" connection between the individual interconnect flow plates which will provide a much more ideal electrical connection than the one in a memori stack, with a minimum of heat dissipated to the surroundings.
  • Fig. 1 illustrates an embodiment of a bi-polar fuel cell stack, electrical connected in succession
  • Fig. 2 illustrates an embodiment of a bi-polar fuel cell stack, electrical connected in course.
  • Fig. 3 illustrates an embodiment of a mono-polar fuel cell stack, electrical connected in course.
  • Fig. 4 illustrates an embodiment of a mono-polar fuel cell stack, electrical connected in serie.
  • Fig. 5 illustrates an embodiment of a mono-polar fuel cell stack, electrical connected in parallel.
  • Fig. 6 illustrates an exploded view of simple 2 cell DMFC battery.
  • Fig. 7 illustrates a MEA on top of an anode interconnect flow plate.
  • FIG. 8 illustrates an enlargement of details in figure 7.
  • FIG. 9 illustrates a MEA on top of a cathode interconnect flow plate.
  • Fig. 10 illustrates an enlargement of details in figure 9.
  • Fig. 11 illustrates an embodiment of a fuel cell comprising cathode interconnection plates and anode interconnection plates.
  • Fig. 12 illustrates an embodiment of an Anode Interconnect Flow Plate Assembly (AIFPA) comprising an anode flow plate and two anode interconnection plates.
  • AIFPA Anode Interconnect Flow Plate Assembly
  • Fig. 13 illustrates an embodiment of a Cathode Interconnect Flow Plate Assembly (CIFPA) comprising a cathode flow plate and two cathode interconnection plates.
  • CIFPA Cathode Interconnect Flow Plate Assembly
  • Fig. 14 illustrates an embodiment of a fuel cell wherein the anode interconnect flow plate assembly and the cathode interconnect flow plate assembly sections are put together.
  • Fig. 15 illustrates an embodiment of a fuel cell according to figure 14, wherein two GPM's have replaced two of the MEAs.
  • Fig. 16 illustrates an embodiment of a fuel cell according to figure 14 wherein the connections between the AIFPA and CIFPA and load is shown
  • Fig. 17 illustrates an embodiment of a DMFC stack design with a parallel connection design, furthermore a CIFPA and AIFPA is shown.
  • Fig. 18 illustrates an embodiment of a DMFC stack design as shown in figure 17 further showing fuel and air distribution lines.
  • Fig. 19 illustrates an embodiment of a DMFC stack design wherein two of the MEAs has been replaced with GPMs. It also shows the fuel and air distribution lines.
  • Fig. 20 illustrates the embodiment in figure 19 with the electrical parallel connection design.
  • Fig. 21 illustrates an embodiment of a DMFC stack design illustrating the electrical serial connection design and the fuel and air distribution design.
  • Fig. 22 illustrates an embodiment of a DMFC stack design illustrating the electrical serial connection design and the fuel and air distribution design, wherein two of the MEAs has been replaced by two GPMs.
  • Fig. 23 illustrates the embodiment of the DMFC stack shown in figure 21 with only the electrical connection design.
  • Fig. 24 illustrates the embodiment of the DMFC stack shown in figure 22 with only the electrical connection design.
  • Fig. 25 illustrates a second embodiment of a cathode flow plate.
  • Fig. 26 illustrates an embodiment of screening walls comprising a sensor and cable.
  • Fig. 27 illustrates an embodiment of an anode flow plate.
  • Fig. 28 illustrates an embodiment of channel walls comprising a sensor and cable.
  • Fig. 29 illustrates a schematic view of a flow plate having two channel systems. One channel on each side.
  • Fig. 30 illustrates a second embodiment of a flow plate having two channel systems.
  • Fig. 31 illustrates an embodiment of a stack and schematic electrical wires.
  • Fig. 32 illustrates an embodiment of a stack comprising two MEAs.
  • Fig. 33 illustrates an embodiment of a stack comprising two MEAs and two GPMs.
  • Fig. 34 illustrates an embodiment of fluid flow pattern in a stack.
  • Fig. 35 illustrates a first embodiment of an cathode flow plate.
  • Fig. 36 illustrates the cross section A-A of the anode flow plate in figure 35.
  • Fig. 37 illustrates an embodiment of a cathode interconnect plate.
  • Fig. 38 illustrates the cross section A-A of the cathode interconnect plate in figure 37.
  • Fig. 39 illustrates an embodiment of an anode interconnect plate
  • Fig. 40 illustrates the cross section A-A of the anode interconnect plate in figure 39.
  • Fig. 41 illustrates an embodiment of an anode interconnect plate.
  • Fig. 42 illustrates the cross section A-A of the anode interconnect plate in figure 41.
  • Fig. 43 illustrates the backside of the anode interconnect plate in figure 41.
  • Fig. 44 illustrates the cross section B-B of the anode interconnect plate in figure 41.
  • Fig. 45 illustrates an possible embodiment of a flow plate assembly with integrated repertoire connections.
  • Figure 6 shows an embodiment of a DMFC stack that is built up around the MEAs which are the components conducting the electro chemical process. From the top the stack comprises a top end plate 8, a cathode flow plate 6, a MEA 4, an anode flow plate 2, a MEA 4, a 15 cathode flow plate 6 and a bottom end plate 9.
  • the MEAs are preferably sandwiched between an, on the one side, anode interconnect flow plate and on the other side a cathode interconnect flow plate.
  • the anode plate (AIFPA) is preferably in direct contact with the anode surface of 2 MEAs and may have a specially 20 designed flow field in order to achieve an optimal distribution of the fuel to the MEA surface.
  • the cathode plate (CIFPA) is preferably in direct contact with the cathode side of the MEA, and the flow field is designed to distribute the air needed for reduction of the H+ migrating 25 through the MEA.
  • anode and cathode flow plates may be stacked, and the total potential is a multiple of the numbers of MEAs and the actual voltage level during operation if connected in memori.
  • Figure 8 shows a cross view of the fuel flow pattern wherein the methanol/water (fuel) 30 solution preferably flows up in the dedicated distribution channel 20, and when meeting an anode flow plate see figure 7 and 8, some of the fuel 21 will enter the anode flow field channel and thus be able to get in direct contact with the active surface area of the MEA.
  • the active area of the MEA is preferably positioned with high accuracy above the flow field area of the anode plate in order to obtain as large contact area as possible between the 35 MEA and the fuel liquid.
  • the fuel 21 inside the anode flow plate is preferably able to react with 2 MEAs, see fig. 7 and 8. Only the top MEA is illustrated.
  • the functionality of the cathode flow plate is preferably similar to the anode flow plate, however in the cathode flow plate a gas is transported instead of a liquid, see figure 9 and 40 10.
  • Figure 9 and 10 shows an embodiment of the cathode flow plate preferably comprising dedicated air conveying channels 33, in order to provide a structure so that at least some of the air 23 will travel along these channels and thereby preferably come in direct contact with the surface of preferably 2 MEAs.
  • the air enters the cathode flow plate from an air distribution channel 24. The air will exit the cathode flow plate trough an exit channel.
  • Figure 11 shows an embodiment of a fuel cell stack comprising a top end plate 8, a first cathode interconnect plate 5, a cathode flow plate 6, a second cathode interconnect plate 7, a MEA 4, a first anode interconnect plate 1, an anode flow plate 2, a second anode interconnect plate 3, a MEA 4, a first cathode interconnect plate 5, a cathode flow plate 6, a second cathode interconnect plate 7 and a bottom end plate.
  • Figure 12 shows an embodiment of a anode interconnect flow plate assembly.
  • the unit preferably comprises a first anode interconnect plate 1, an anode flow plate 2, and a second anode interconnect plate 3.
  • the anode flow plate and the first and second anode interconnection plates may be integrated into one unit by preferably adding a metallic surface to the anode flow plate side surfaces.
  • FIG. 13 shows an embodiment of a cathode interconnect flow plate assembly.
  • the unit preferably comprises a first cathode interconnect plate 5, a cathode flow plate 6, and a second cathode interconnect plate 7.
  • the cathode flow plate and the first and second cathode interconnection plates may be integrated into one unit by preferably adding a metallic surface to the anode flow plate side surfaces.
  • the first and second cathode interconnect plate 5 and 7 preferably comprises contact protrusions, shown in figure 37 and 38, on the surface towards-the MEA (not shown) in order to obtain a larger contact area, which increases the efficiency of the cathode cell unit. Furthermore the first and second cathode interconnect plate preferably comprises flow facilitating flaps for directing the flow of gas such as air from the cathode flow plate 6 through the interconnection plates towards the surface of a MEA/GPM in order to increase the efficiency of the cathode cell unit.
  • Figure 14 shows an embodiment of a fuel cell stack comprising four MEAs 4, two end plates 8 and 9, two anode interconnect flow plate assemblies and two cathode interconnect flow plate assemblies.
  • Figure 15 shows an embodiment of a fuel cell stack comprising two MEAs 4, two GPM's, two anode interconnect flow plate assemblies and two cathode flow plate assemblies.
  • the gas permeable membranes may be sandwiched between anode interconnection plates and cathode interconnection plates.
  • the function of the GPM preferably is to facilitate the removal of gas the interconnection flow plates may be superfluous and thus may be removed or replaced with a layer that facilitates the exposure of the GPM surface to the fluid. Hence weight and space may be saved by preferably removing the interconnection plate facing the GPM.
  • Figure 16 shows schematically how the electrical connection may be connected between the individual flow plate assemblies within the stack, also shown in figure 14.
  • Figure 17 illustrates a schematic electrical parallel connection design comprising four MEAs. Furthermore the figures illustrates a cathode interconnect flow plate assembly and an anode interconnect flow plate assembly, the cathode interconnect flow plate assembly comprising a first cathode interconnect plate CI, a second cathode interconnect plate C2 and a cathode flow plate C3, the anode interconnect flow plate assembly comprising a first anode interconnect plate Al, a second anode interconnect plate A2 and an anode flow plate A3. These elements are also shown in figure 18 to 24.
  • Figure 18 illustrates fuel and air distribution lines wherein the fuel lines schematically are connected to the anode flow plates and the air distribution lines preferably are connected to the cathode flow plate.
  • Figure 19 illustrates a second embodiment wherein two of the MEAs has been replaced by two GPM's. It shows the flow distribution lines and electric schemes of the system. Whereas in figure 18 illustrates only the electric scheme.
  • Figure 21 illustrates an embodiment of a electrical serial connection design, and the fuel and air distribution system wherein the system comprises four MEAs.
  • figure 22 illustrates an embodiment of a design wherein two of the MEAs has been replaced by two GPMs.
  • Figure 23 to 24 illustrates only the electric schemes of the embodiments illustrated in figure 21 and 22 respectively.
  • the cathode flow plate 6, shown in figures 6, 9, 13 and 25, may be manufactured in a material able to transport electrons such as metal, carbon etc.
  • the cathode flow plate may be manufactured in an electrically isolating material such as rubber or plastic.
  • the cathode flow plate is manufactured in plastic.
  • the cathode flow plate shown in figure 25 preferably comprises a frame 30 also called core member, a gas/air inlet distribution channel 31, at least one gas/air outlet 32. From the inlet distribution channel to the air outlet air conveying channels 33 are formed in order to provide an exhaust system for the exhaust that arise in the electro chemical process.
  • the conveying channels 33 are preferably separated by screening walls 34, that may constitute walls to the conveying channels and also act as a support towards the cathode interconnection plates 5 and 6 shown in figure 13. In this way the screening walls may provides support that improves the contact between the MEA and interconnection plates.
  • screening walls may comprise sensor means 35, such as temperature sensors, C0 2 sensors, CO sensors or any other sensor for measuring a parameter that could be of importance for the management of a fuel cell in order to obtain a more efficient utilisation of a fuel cell.
  • the shorter screening wall 36 is preferably for making space for a mounting screw when mounting the stack.
  • the mounting of a cell is done by a plurality of mounting means such as bolts, screws etc. in order to achieve an even distribution of forces applied to the fuel cell stack.
  • the sensors may be placed anywhere on the frame 30 or in one or more of any of the screening walls 34 as shown in figure 26.
  • One sensor may be placed in the vicinity of the inlet distribution channel 31 and another may be placed in the vicinity of air outlet 32, in this way it is possible to measure the temperature difference of the inlet and outlet air.
  • Cables for communicating with the sensors may preferably be formed inside the screening walls 34 as shown in figure 26. However it may also be possible to situate them on the outside of the screening walls 34 or frame 30.
  • Sensors may be situated in all cathode flow plates within a fuel cell, in this way it may be possible to compare different layers and track errors if a layer is malfunctioning and thus acting differently from the other layers in a stack.
  • the sensors are connected to a control unit (not shown) where the data is collected and turned into information for evaluating the status of the fuel cell.
  • the control unit may comprise software for controlling a fan and a fuel pump for controlling the amount of fuel and air being provided into the cell.
  • parameters related to the load driven by the fuel cell such as effect etc. may also be of importance for the control unit in order to control the fuel cell in the most efficient way.
  • load parameters load parameters
  • internal parameters it is possible to achieve an intelligent steering of a fuel cell.
  • the anode flow plate 2 shown in figures 6, 7, 12 and 27, may be manufactured in a material able to transport electrons such as metal, carbon etc.
  • the anode flow plate may be manufactured in a electrically isolating material such as rubber or plastic.
  • the anode flow plate is manufactured in plastic.
  • the anode flow plate shown in figure 27 preferably comprises a frame 40, a fuel inlet distribution channel 41, at least one fuel outlet 42. From the inlet distribution channel to the fuel outlet fuel conveying channels 43 are formed in order to increase the contact time and contact area between a MEA and the fuel.
  • the channel walls 44, between the channels also function as support towards the anode interconnection plates 1 and 3 shown in figure 12. In this way the walls preferably provides means that improves the contact between the MEA and interconnection plates.
  • the walls 44 may comprise sensor means 45, such as temperature sensors, or any other sensor for measuring a parameter that could be of importance for the management of a fuel cell in order to obtain a more efficient fuel cell.
  • sensor means 45 such as temperature sensors, or any other sensor for measuring a parameter that could be of importance for the management of a fuel cell in order to obtain a more efficient fuel cell.
  • the sensors may be placed anywhere on the frame 40 or in one or more of any of the 10 walls 44 as shown in figure 28.
  • One sensor may be placed in the vicinity of the inlet distribution channel 41 and another may be placed in the vicinity of fuel outlet 42, in this way it is possible to measure the temperature difference of the inlet and outlet fuel.
  • Cables 46 for communicating with the sensors may preferably be formed inside the walls 15 44 as shown in figure 28. However it may also be possible to situate them on the outside of the walls 44 or frame 40.
  • the sensors are connected to a control unit (not shown) where the data is collected and turned into information for evaluating the status of the fuel cell. 20
  • Sensors may be situated in all anode flow plates 2 within a fuel cell, in this way it may be possible to compare different layers and to track errors if a layer functions differently from the other layers.
  • sensors may be situated in both the anode and cathode flow plates within a fuel cell.
  • the result from the all the sensors preferably provides a real-time diagnosis of a fuel cell during operation.
  • Figure 29 and 30 shows a second embodiment of a combined flow plate preferably comprising two channels, one on each side of the flow plate.
  • the channels are preferably separated since the depth of them are preferably less than half the distance of the height of the flow plate.
  • the entrance 51 and outlet 52 for the fuel or air may be placed either on the same sides or as shown in the figure 29 on different sides according to the application in which the flow plate is to be used in.
  • the flow plate may comprise cathode flow channels according to figure 25 on one side, and anode distribution channels according to figure 26 on the other side.
  • Figure 31 shows a schematic illustration of how the interconnection plates preferably may be connected in a stack comprising four MEAs.
  • Gaskets 15 providing a sealing function are preferably mounted within the stack in order to avoid leakage.
  • the MEAs and GPMs are preferably mounted within the gasket frame, also shown in figure 6, 7 and 32.
  • the thickness of the gaskets 15 are preferably not thicker than a the thickness of a MEA.
  • the contact peaks 50 and 57 in figure 37 and 42 should preferably get in contact with the MEA or GPM located in the gasket.
  • Figure 34 shows an embodiment of a fluid pattern inside a stack comprising 4 MEAs.
  • Figure 35 show a second embodiment of a cathode flow plate comprising conveying channels 33 and screening walls 34. Furthermore the second embodiment preferably comprises weak sections 59, for facilitating the removal of at least a part of the frame 30. By having a plurality of weak sections it gives a manufacturer more freedom designing a fuel cell.
  • Figure 37 shows an embodiment of a cathode interconnection plate 5 and 7, comprising projecting peaks 50 and 51.
  • the contact peaks 50 are preferably smaller than the directing peaks 51 in order to make bigger area for the directing peaks.
  • the function of the directing peaks 51 is preferably to direct air from a flow channel 33 towards the surface of a MEA or GPM in order to remove exhaust more efficiently and to cool off the cell.
  • the function of the contact peaks 50 is preferably to increase the contact area and to obtain a better contact between the cathode interconnection plate and a MEA or GPM.
  • the directing peaks 51 may have a concave side in order to direct the flow of air more efficiently.
  • the directing peaks may be organised in groups wherein the opening of the directing peaks 51 within the group are oriented in the same direction.
  • the contact peaks 50 are preferably formed as flaps, as shown in figure 38.
  • the contact peaks are preferably bent up to 45 degrees from the cathode interconnection plate in order to be elastic towards pressure. However they could be bent more upwards but in that case the edge or peak of the contact peaks should preferably be designed in such a way so as to avoid penetration of the surface of a MEA or GPM.
  • One solution could be to form the contact peaks with round and smooth peaks and edges.
  • Another solution could be to bend the top part of the contact peak slightly downwards towards the interconnection plate in order to avoid having sharp edge towards the MEA or GPM.
  • Other solutions are also possible such as a granular surface.
  • An alternative solution could be to punch the plate on one side with a small circular tool in order to obtain peaks on the other side of the plate.
  • contact arches could be formed on the plate by for example punching or by welding.
  • the arches would preferably have a smooth and round contact area towards a MEA or GPM.
  • the orientation of the flaps 50 and 51 may preferably be as shown in figure 37 and 38. However they may be oriented in any direction relating to each.
  • the contact peaks 50 could be turned 90 degrees in relation to the directing peaks 51.
  • connection hole 52 in one of the four connection legs is for connecting electrical conducting means such as wires.
  • the cut hole 53 is for facilitating the removal of a connection leg that is not needed.
  • this design having four connection leg gives the manufacturer a larger number of choices when designing a fuel Cell.
  • connection legs Preferably only one leg is needed, thus when a design is chosen the other three connection legs are preferably removed.
  • connection legs may be located any where on the plate shown in figure 37, thus not necessarily in the corners.
  • Figure 41 shows an embodiment of an anode interconnection plate 1 and 2, comprising slits 56 and contact peaks 57 similar to the contact peaks described above for the cathode interconnection plate shown in figure 37.
  • the slits 56 may preferably be parallel with the distribution channels 41 in an anode flow plate.
  • the contact peaks 57 are preferably formed as flaps as shown in figure 42, in order to contact the surface of a MEA. However they may be formed as described above for the cathode interconnection plate shown in figure 37.
  • the orientation of the contact peaks 57 on the anode interconnection plate is preferably as shown in figure 41 and 42 wherein the opening of the flaps are oriented towards a central point on the anode interconnection plate.
  • a group of contact peaks may preferably be facing in the same direction.
  • orientations of the contact peaks could be used wherein the opening of the contact peaks or groups of contact peaks may be oriented in any direction.
  • Figure 45 shows an embodiment of an assembly of flow plates wherein the flow plates are connected by bridges 60.

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Abstract

L'invention concerne l'amélioration de systèmes de pile à combustible qui consiste à introduire des éléments qui rendent la pile à combustible plus efficace tout en réduisant la taille d'un empilement de piles à combustible. L'amélioration de plaques d'interconnexion et l'introduction d'une membrane perméable au gaz rendent l'écoulement de fluides plus approprié à cette fin. Des capteurs intégrés dans la pile à combustible fournissent des données de valeur. Ce sont là certaines des caractéristiques qui renforcent l'efficacité dudit système de pile à combustible.
PCT/DK2004/000264 2003-04-08 2004-04-07 Pile a combustible WO2004091023A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA200300540 2003-04-08
DKPA200300540 2003-04-08

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WO2004091023A2 true WO2004091023A2 (fr) 2004-10-21
WO2004091023A3 WO2004091023A3 (fr) 2004-11-25

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016085360A1 (fr) * 2014-11-24 2016-06-02 Instytut Energetyki - Instytut Badawczy Empilement de piles à combustible haute température pour production d'énergie électrique

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Publication number Priority date Publication date Assignee Title
GB2305169A (en) * 1995-09-14 1997-04-02 Univ Napier Solid oxide fuel cells
US6071635A (en) * 1998-04-03 2000-06-06 Plug Power, L.L.C. Easily-formable fuel cell assembly fluid flow plate having conductivity and increased non-conductive material
DE19921816C1 (de) * 1999-05-11 2000-10-26 Andre Peine Brennstoffzellen-System und Brennstoffzelle für derartiges System
DE10034401A1 (de) * 2000-07-14 2002-01-24 Daimler Chrysler Ag Brennstoffzellen-System mit wenigstens einer mit einem flüssigen Kühlmittel/Brennstoff-Gemisch betriebenen Brennstoffzelle
EP1333519A2 (fr) * 2002-01-31 2003-08-06 Hewlett-Packard Company Pile à combustible avec alimentation en combustible par gouttelles de combustible
EP1394877A1 (fr) * 2002-07-31 2004-03-03 SFC Smart Fuel Cell AG Element conçu sous forme de plaques pour piles à combustible
EP1429406A1 (fr) * 2002-12-11 2004-06-16 SFC Smart Fuel Cell GmbH Elements d'encadrement pour assemblage monopolaire de piles à combustible

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Publication number Priority date Publication date Assignee Title
GB2305169A (en) * 1995-09-14 1997-04-02 Univ Napier Solid oxide fuel cells
US6071635A (en) * 1998-04-03 2000-06-06 Plug Power, L.L.C. Easily-formable fuel cell assembly fluid flow plate having conductivity and increased non-conductive material
DE19921816C1 (de) * 1999-05-11 2000-10-26 Andre Peine Brennstoffzellen-System und Brennstoffzelle für derartiges System
DE10034401A1 (de) * 2000-07-14 2002-01-24 Daimler Chrysler Ag Brennstoffzellen-System mit wenigstens einer mit einem flüssigen Kühlmittel/Brennstoff-Gemisch betriebenen Brennstoffzelle
EP1333519A2 (fr) * 2002-01-31 2003-08-06 Hewlett-Packard Company Pile à combustible avec alimentation en combustible par gouttelles de combustible
EP1394877A1 (fr) * 2002-07-31 2004-03-03 SFC Smart Fuel Cell AG Element conçu sous forme de plaques pour piles à combustible
EP1429406A1 (fr) * 2002-12-11 2004-06-16 SFC Smart Fuel Cell GmbH Elements d'encadrement pour assemblage monopolaire de piles à combustible

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Title
MENNOLA T ET AL: "Measurement of ohmic voltage losses in individual cells of a PEMFC stack" JOURNAL OF POWER SOURCES, ELSEVIER SEQUOIA S.A. LAUSANNE, CH, vol. 112, no. 1, 24 October 2002 (2002-10-24), pages 261-272, XP004387656 ISSN: 0378-7753 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016085360A1 (fr) * 2014-11-24 2016-06-02 Instytut Energetyki - Instytut Badawczy Empilement de piles à combustible haute température pour production d'énergie électrique

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