WO2021121763A1 - Couche de diffusion de gaz pour cellule électrochimique - Google Patents

Couche de diffusion de gaz pour cellule électrochimique Download PDF

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Publication number
WO2021121763A1
WO2021121763A1 PCT/EP2020/081163 EP2020081163W WO2021121763A1 WO 2021121763 A1 WO2021121763 A1 WO 2021121763A1 EP 2020081163 W EP2020081163 W EP 2020081163W WO 2021121763 A1 WO2021121763 A1 WO 2021121763A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas diffusion
diffusion layer
layer
closed
closed structures
Prior art date
Application number
PCT/EP2020/081163
Other languages
German (de)
English (en)
Inventor
Ulrich Berner
Thilo Lehre
Andreas Gehrold
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2021121763A1 publication Critical patent/WO2021121763A1/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
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/8605—Porous electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8803—Supports for the deposition of the catalytic active composition
    • H01M4/8807—Gas diffusion layers
    • 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
    • H01M8/023—Porous and characterised by the material
    • H01M8/0234—Carbonaceous material
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2250/00—Fuel cells for particular applications; Specific features of fuel cell system
    • H01M2250/20—Fuel cells in motive systems, e.g. vehicle, ship, plane
    • 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
    • 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
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/40—Application of hydrogen technology to transportation, e.g. using fuel cells

Definitions

  • the present invention relates to a gas diffusion layer for an electrochemical cell, which has a multiplicity of conductive, closed structures with at least one passage.
  • Fuel cells or batteries as examples of electrochemical cells are typically used as electrical power sources for the supply of electric motors or machines. Electric drives are increasingly becoming part of a vehicle drive for electric bicycles, electric cars, hybrid vehicles and the like.
  • fuel cell vehicles are characterized by a significantly longer range and faster refueling times.
  • PEM polymer electrolyte membrane fuel cell
  • GDB carbon fiber fleece
  • MPL microporous particle layer
  • the gas diffusion layer has various tasks within, for example, a fuel cell. This includes the substance distribution of oxygen, hydrogen, water, etc., as well as a power line, a heat conduction and a force distribution of contact pressures.
  • the fiber fleece that is typically used is very permeable to gases in the plane of the gas diffusion layer and helps with the transverse distribution of the media, the heat and the current under webs of bipolar plates that are set up to divert the current to the outside.
  • the carbon fiber structures are brittle and can break during the manufacture of the GDL or during the assembly process of the cells or the stack.
  • the resulting fiber ends from the GDL can protrude from the MPL and consequently penetrate the very thin ( ⁇ 20pm) and mechanically sensitive catalyst-coated membrane. This leads to irreparable damage to the electrochemical cell and, in a very short time, to failure of the electrochemical cell.
  • a gas diffusion layer for an electrochemical cell and an electrochemical cell according to the features of the independent claims are specified, which at least in part achieve the stated objects.
  • Advantageous configurations are the subject matter of the dependent claims and the description below.
  • a gas diffusion layer for an electrochemical cell having a fluid-permeable structure and has a plurality of electrically conductive, closed structures, each with at least one passage.
  • the semipermeable membrane serves to separate the two electrode spaces of the fuel cell.
  • Such a gas diffusion layer can electrically and thermally connect an electrocatalytic reaction layer located on the membrane side to the bipolar plate and ensure the media transport to and from the electrocatalytic reaction layer.
  • Carbonized closed structures with at least one passage can be produced, for example, in that the starting materials used for the carbonization are brought into the desired shape and a carbonization process then follows. This is shown, for example, in RSC Adv., 2015, 5, 33294-33298, in which the starting material is amylose and 3-pentadecylphenol (PDP).
  • the starting material is amylose and 3-pentadecylphenol (PDP).
  • PDP 3-pentadecylphenol
  • the amylose and PDP are mixed in dimethyl sulfoxide and spin coated onto a silicon wafer. This is followed by crosslinking of the amylose / PDP film with formaldehyde vapor and the carbon micro-rings are formed after pyrolysis under a nitrogen atmosphere.
  • closed structures do not have any open ends, mechanical damage to adjacent layers, such as for example the semipermeable membrane and / or an electrode, can be virtually ruled out by these structures.
  • These closed structures can be mechanically significantly more resistant to bending or compression fractures.
  • Such closed structures in a gas diffusion layer have the advantage that they are too small or short to break through mechanical forces, such as bending, and also do not have any sharp-edged, protruding ends per se.
  • Such closed structures with at least one passage can, for example, in the form of a torus, a closed fiber ring, a closed ring, in the form of loops or as donut-shaped structures or in the form of hemispherical outer structures.
  • the use of such closed structures results in an improved thermal and electrical conductivity within the plane of the gas diffusion layer and through the layers due to the three-dimensionality compared to, for example, carbon particles, i.e. an improvement in all spatial directions, since fewer contact points between structures over a certain period Distance are necessary.
  • installing the closed structures with at least one passage improves the long-distance transport of heat and current within the layer of the gas diffusion layer, since fewer surface contacts have to be overcome for the heat transfer or the current transfer.
  • the passage of the closed structures is sufficiently large to promote media transport within the gas diffusion layer.
  • Good media transport is particularly important for the areas of the gas diffusion layer that lie under the webs of the bipolar plate, so the media transport can be improved by homogenizing the properties of the gas diffusion layer.
  • the webs of the bipolar plate conduct the electrical current and a heat flow from the gas diffusion layer to the bipolar plate.
  • the closed structure is ring-shaped and a diameter of the passage is greater than a diameter of a bead of the structure.
  • the proportion of closed structures with at least one passage in the gas diffusion layer is at least 90%. The percentage relates to a ratio of closed structures with at least one passage to a fiber content of the gas diffusion layer.
  • the closed structures have a diameter between 1 pm and 500 pm, and preferably have a diameter between 2 pm and 100 pm, and more preferably between 5 pm and 30 pm. These dimensions allow ideal embedding and alignment in the gas diffusion layer, which itself has target thicknesses of 30-250 ⁇ m. By matching the sizes of the closed structures to the total layer thickness, the number of contact points between the closed structures is minimized, so that the transport processes achieve ideal electrical and thermal magnitudes and at the same time the mechanical stability of the layer is not compromised
  • the closed structures have a height between 100 nm and 50 pm, and the height preferably have a value between 0.5 pm and 10 pm.
  • This height creates structures that offer an ideal cross-section for the bulk conductive properties and ensure sufficient mechanical stability. Thicker structures would be too stable, i.e. the advantageous flexibility / spring effect would not be expected, thinner structures would break under mechanical stress, so that the advantage of “no open ends” would not be guaranteed.
  • a height of the closed structure characterizes either a maximum diameter of a bead of the closed structure, the entire bead forming the closed structure with at least one passage.
  • the height of the closed structure can also be greater than a diameter of the bead at the thickest point of the closed structure, for example by changing an annular closed structure by twisting it in space.
  • At least some of the closed structures provide the structure for the gas diffusion layer.
  • structuring is to be understood in particular as meaning that the fibers formed in this way build up a macroscopic basic structure with one another, which determines the external shape of the gas diffusion layer.
  • the closed structures are connected to one another with a binding agent with at least one further closed structure by means of a binding agent.
  • a binding agent for the construction of a structure, the respective closed structures with passage can be mechanically connected to one another with a binding agent.
  • a binder can be, for example, PTFE.
  • a structure built up in this way can correspondingly replace a carbon fiber fleece made up of elongated carbonized fibers.
  • the gas diffusion layer have carbon particles.
  • a particle-based microporous layer By introducing carbon particles into the closed structures with a passage, a particle-based microporous layer can be improved in terms of conduction of electricity and conduction of heat within the gas diffusion layer.
  • An overall layer constructed in this way can provide both the function of a microporous layer and the function of an adjacent macroporous layer.
  • a gas diffusion layer constructed in this way thus fulfills both the function of a microporous layer and the functions of a macroporous layer Layer and can make an additional carbon fiber fleece in the sense of a gas diffusion backing (GDB) for the construction of a fuel cell obsolete.
  • GDB gas diffusion backing
  • the gas diffusion layer is at least partially penetrated by a microporous functional layer in order to provide both a microporous partial area and a macroporous partial area for a structure of the electrochemical cell.
  • the plurality of closed structures have carbonized starting materials or inorganic ceramics or metals or stainless steel or copper or nickel or titanium or alloys made from these metals.
  • the material suitable for the respective purpose can be selected.
  • An electrochemical cell which has a membrane, a catalytic reaction layer and a gas diffusion layer adjoining the reaction layer, as has been described above.
  • An electrochemical cell constructed in this way can be manufactured more cheaply and have fewer defects, in particular with regard to the semipermeable membrane.
  • a gas diffusion layer with the carbon-based closed structures with a passage these are mixed together with a binding agent and possibly a conductive additive, e.g. a highly conductive carbon powder, in a solvent and a porous gas distribution layer is created using conventional coating methods such as doctoring and subsequent drying generated.
  • a conductive additive e.g. a highly conductive carbon powder
  • a porous gas distribution layer is created using conventional coating methods such as doctoring and subsequent drying generated.
  • the manufacturing processes can be exactly the same as those of a fiber GDL.
  • the different expansion of the structures ensures that an arrangement is established in the plane, so that the in-plane conductivity for heat and electricity is favored.
  • the carbon-based closed structures with passage can be used directly in a typical particle-based microporous layer Layer can be added as an additive.
  • the otherwise typically isotropic microporous layer can thus be significantly improved with regard to the functions of heat and power conduction in the plane direction without significantly influencing the gas transport.
  • FIGS. 1 to 3 Exemplary embodiments of the invention are illustrated with reference to FIGS. 1 to 3 and are explained in more detail below. It shows:
  • FIG. 1 characteristic dimensions of a closed structure with a passage
  • FIG. 2 shows a structure of a gas diffusion layer
  • FIG. 3 shows a gas diffusion layer with a characteristic layer thickness.
  • FIG. 1 outlines the characteristic dimensions of a closed structure 100 with passage 120 for a gas diffusion layer 200 for the construction of an electrochemical cell.
  • the closed structure 100 of FIG. 1 has an outer dimension 124 and a diameter 122 of a bead of the closed annular structure 100.
  • FIG. 2 sketches a structure of a gas diffusion layer 200, which is built up to give structure by the closed structures 240 in that the structures 240 are connected to one another with binders 260.
  • the closed structures 240 in the gas diffusion layer 200 can be aligned in the plane of the layer. This results in a thickness 220 of the gas diffusion layer 200.
  • FIG. 3 outlines a gas diffusion layer 300 with a characteristic layer thickness 320, which has a multiplicity of closed structures 240 with a passage, which are aligned in the gas diffusion layer 300 in the plane of the layer.
  • the gas diffusion layer 300 also has Carbon particles 340 and binder 260.
  • the plurality of closed structures 240 with a passage are thus embedded in the gas diffusion layer 300 in a composite with carbon particles 240 and binder 260 and can improve both heat conduction and electrical conductivity within the layer, since they have to overcome fewer interfaces over their length than Adjacent carbon particles 340.
  • a gas diffusion layer 200 constructed in this way thus fulfills both the function of a microporous layer and the functions of a macroporous layer and can make an additional carbon fiber fleece in the sense of gas diffusion backing (GDB) obsolete for the construction of a fuel cell.
  • GDB gas diffusion backing

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

Abstract

L'invention concerne une couche de diffusion de gaz pour une cellule électrochimique, la couche de diffusion de gaz comprenant une structure perméable aux fluides et une pluralité de structures fermées électroconductrices, chacune ayant au moins un passage.
PCT/EP2020/081163 2019-12-17 2020-11-05 Couche de diffusion de gaz pour cellule électrochimique WO2021121763A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102019219773.6 2019-12-17
DE102019219773.6A DE102019219773A1 (de) 2019-12-17 2019-12-17 Gasdiffusionsschicht für eine elektrochemische Zelle

Publications (1)

Publication Number Publication Date
WO2021121763A1 true WO2021121763A1 (fr) 2021-06-24

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Application Number Title Priority Date Filing Date
PCT/EP2020/081163 WO2021121763A1 (fr) 2019-12-17 2020-11-05 Couche de diffusion de gaz pour cellule électrochimique

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DE (1) DE102019219773A1 (fr)
WO (1) WO2021121763A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011083118A1 (de) * 2011-09-21 2013-03-21 Future Carbon Gmbh Gasdiffusionsschicht mit verbesserter elektrischer Leitfähigkeit und Gasdurchlässigkeit
US20130316075A1 (en) * 2007-10-16 2013-11-28 Lg Chem, Ltd. Cathode for fuel cell having two kinds of water-repellency and method of preparing the same and membrane electrode assembly and fuel cell comprising same
US20160013503A1 (en) * 2012-02-08 2016-01-14 Toyota Boshoku Kabushiki Kaisha Gas diffusion layer for fuel cell, fuel cell, and method of manufacturing gas diffusion layer for fuel cell
KR20180070748A (ko) * 2016-12-16 2018-06-27 현대자동차주식회사 연료전지용 기체확산층 및 그 제조방법

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130316075A1 (en) * 2007-10-16 2013-11-28 Lg Chem, Ltd. Cathode for fuel cell having two kinds of water-repellency and method of preparing the same and membrane electrode assembly and fuel cell comprising same
DE102011083118A1 (de) * 2011-09-21 2013-03-21 Future Carbon Gmbh Gasdiffusionsschicht mit verbesserter elektrischer Leitfähigkeit und Gasdurchlässigkeit
US20160013503A1 (en) * 2012-02-08 2016-01-14 Toyota Boshoku Kabushiki Kaisha Gas diffusion layer for fuel cell, fuel cell, and method of manufacturing gas diffusion layer for fuel cell
KR20180070748A (ko) * 2016-12-16 2018-06-27 현대자동차주식회사 연료전지용 기체확산층 및 그 제조방법

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
RSC ADV, vol. 5, 2015, pages 33294 - 33298

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