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EP4374437A1 - Method for manufacturing bipolar plates - Google Patents

Method for manufacturing bipolar plates

Info

Publication number
EP4374437A1
EP4374437A1 EP22754902.9A EP22754902A EP4374437A1 EP 4374437 A1 EP4374437 A1 EP 4374437A1 EP 22754902 A EP22754902 A EP 22754902A EP 4374437 A1 EP4374437 A1 EP 4374437A1
Authority
EP
European Patent Office
Prior art keywords
component
graphite
composition
polymer
bipolar plate
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
EP22754902.9A
Other languages
German (de)
French (fr)
Inventor
Marie HUZAR-EA
Stéphane Bizet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arkema France SA
Original Assignee
Arkema France SA
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 Arkema France SA filed Critical Arkema France SA
Publication of EP4374437A1 publication Critical patent/EP4374437A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/54—Reclaiming serviceable parts of waste accumulators
    • 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
    • H01M8/0226—Composites in the form of mixtures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/003—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0001—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/036—Bipolar electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • 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
    • H01M4/8626—Porous electrodes characterised by the form
    • H01M4/8631—Bipolar 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
    • H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
    • H01M4/8652—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites as mixture
    • 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
    • H01M4/8875—Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support
    • 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
    • H01M8/0213—Gas-impermeable carbon-containing materials
    • 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
    • H01M8/0221—Organic resins; Organic polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/755—Membranes, diaphragms
    • 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
    • H01M2004/8678—Inert electrodes with catalytic activity, e.g. for fuel cells characterised by the polarity
    • H01M2004/8694—Bipolar electrodes
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/20—Waste processing or separation
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/84—Recycling of batteries or fuel cells

Definitions

  • TITLE METHOD FOR MANUFACTURING BIPOLAR PLATES
  • the present invention relates to a method of making a bipolar plate composition.
  • the invention also relates to processes for manufacturing bipolar plates by injection, extrusion or compression, from said composition, as well as the bipolar plates obtained by these processes.
  • Bipolar plates are used in fuel cells, electrolyzers and in redox flow batteries. They can be made from different materials: metallic bipolar plates, graphite plates and carbon-polymer composite plates.
  • bipolar plates based on organic composite materials is based on the use of conductive fillers (carbon, graphite, etc.) dispersed in a thermoplastic or thermosetting polymer.
  • the fillers will give the bipolar plates the electrical conductivity necessary for collecting the current and the polymer matrix their good mechanical strength necessary for assembling the various elements.
  • Carbon-polymer composite bipolar plates have interesting properties: high electrical conductivity, good corrosion resistance, good performance at high temperature, and good mechanical properties, with a relatively low manufacturing cost.
  • a thermosetting or thermoplastic polymer is used as a matrix for a carbonaceous filler chosen from among graphite, carbon fibers, carbon black or carbon nanotubes.
  • the electrical performance of composite bipolar plates is mainly determined by the carbon charge, the material of the polymer matrix also influences the electrical behavior of the composite.
  • Thermosetting polymer-graphite composites are preferred materials for the fabrication of bipolar plates.
  • composite materials based on thermoplastic polymers in particular thermoplastics stable at high temperatures, have already been used in the manufacture of bipolar plates, in due to their ability to be injection molded or extruded, making them more suitable for automated manufacturing.
  • Such composites have been prepared using polyphenylene sulfide (PPS) or polyether sulfone (PES) containing graphite powder, as reported by Radhakrishnan, S. et al. in the publication: “High-temperature, Polymer-graphite Hybrid Composites for Bipolar Plates: Effect of Processing Conditions on Electrical Properties”, Journal of Power Sources, 2006, Vol. 163, p. 702-707.
  • bipolar plates for fuel cells are: high electronic and thermal conductivities, good mechanical properties such as bending properties, and high gas barrier properties.
  • the invention relates to a method for manufacturing a composition for a bipolar plate, said method comprising the following steps:
  • said composite mixture comes from the recycling of lithium-ion batteries.
  • the recycling of lithium-ion batteries is carried out by a process chosen from among physical separation, pyrometallurgy, hydrometallurgy, or a combination thereof.
  • the different components of the cell are dismantled before they are ground.
  • said at least one carbonaceous conductive filler is graphite used as active filler at the lithium-ion battery anode.
  • said carbonaceous conductive filler is a mixture of graphite and another carbonaceous conductive filler, such as carbon black or carbon nanotubes present in the formulation of the Li-battery anode or cathode. ion.
  • said polymer entering into the composition of said composite mixture is a fluorinated polymer, a water-soluble thickening polymer (such as, for example, carboxymethylcellulose), a polyolefin elastomer (such as, for example, a styrene-butadiene rubber), an acrylic resin (such as carboxylated acrylic polymers) or a mixture of several of these components, including a mixture of different fluoropolymers.
  • a fluorinated polymer such as, for example, carboxymethylcellulose
  • a polyolefin elastomer such as, for example, a styrene-butadiene rubber
  • an acrylic resin such as carboxylated acrylic polymers
  • the invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:
  • the invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:
  • the invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:
  • composition - subjecting said composition to a continuous extrusion process.
  • the invention further relates to the bipolar plates obtained by the methods described above or comprising the composition described above.
  • the present invention makes it possible to overcome the disadvantages of the state of the art. It more particularly provides a process for the manufacture of compositions which can be implemented easily to manufacture bipolar plates.
  • the advantages of this approach using a composite mixture resulting from the recycling of lithium-ion batteries, are to benefit from the good dispersion of the polymer binder in the recycled conductive carbon filler/polymer mixture, which makes it possible to improve the dispersion of the carbon charge in the bipolar plate. This makes it possible to improve the mechanical resistance, the gas barrier properties and the conductivity.
  • SEI solid electrolyte interface
  • This layer of SEI is composed of inorganic elements (LiL, L12O2, L12CO3) and also of polymer fractions resulting from the decomposition of electrolyte solvents. Consequently, this layer of SEI contributes to better flexibility and resistance to cracks, giving the recycled graphite the ability to improve the mechanical properties of the bipolar plate.
  • the percentages indicated in the text are mass percentages.
  • the subject of the invention is the use of a mixture of conductive fillers/polymers resulting from the recycling of lithium-ion batteries for the manufacture of bipolar plates.
  • the invention relates to a method for manufacturing a composition for a bipolar plate, said method comprising the following steps: - providing a composite mixture based on at least one carbonaceous conductive filler and polymer(s) (component A),
  • said method comprises the following characters, possibly combined.
  • said composite mixture is prepared by a lithium-ion battery recycling process chosen from among pyrometallurgy, hydrometallurgy, physical separation based on characteristics of the materials such as particle size, density, magnetic or electrical properties , such as flotation, or a combination thereof.
  • the battery to be recycled is dismantled in order to recover the polymers, carbonaceous fillers and noble metals from the electrodes.
  • the batteries which are recycled are those having an NMC (nickel-manganese-cobalt) or NCA (nickel-cobalt-aluminum) cathode and a graphite anode.
  • the components of a lithium-ion battery are physically separated: cathode/separator/anode, the cathode and the anode are ground, then the hydrometallurgy steps are carried out to selectively recover materials, including cobalt and nickel.
  • Hydrometallurgy residues consist of conductive carbonaceous fillers and polymers such as PVDF that are resistant to leaching and reprecipitation stages, and can therefore be reused according to the present invention.
  • the components of a lithium-ion battery are physically separated: cathode/separator/anode, the cathode and the anode are ground and then flotation or jet sieving is carried out. air allowing to recover the conductive carbonaceous fillers and the sparse and hydrophobic polymer binders, thus separated from the metallic active fillers and the denser metallic current collector residues.
  • the recycling process leads to the recovery of the carbonaceous fillers which are associated with thermoplastic polymers, that is to say the binders of the electrodes.
  • the method according to the invention may comprise a preliminary step which consists in grinding, redispersing and sieving said mixture in order to obtain a powder having a particle size of 500 ⁇ m maximum, preferably less than 200 ⁇ m.
  • a recombination of the conductive carbonaceous filler powders/polymers from the cathode and the anode is carried out by a method of mixing dry powders with equipment such as a ribbon or paddle mixer. It is possible to carry out this recombination in the molten state by an extrusion process making it possible to obtain flakes or friable granules which must then be reground.
  • the cell or the module is ground without carrying out any prior dismantling. It is then possible to recover a mixture of carbonaceous and polymeric conductive fillers either after one or more physical separation step(s) as described above, or as a residue from the hydrometallurgy process.
  • a pyrometallurgy step is carried out to eliminate the polymers present. Only the conductive carbonaceous fillers are then recovered to be used according to the invention.
  • said at least one carbonaceous conductive filler is graphite used as active filler at the lithium-ion battery anode.
  • said carbonaceous conductive filler is a mixture of graphite and another carbonaceous conductive filler, such as carbon black, carbon nanotubes or carbon fibers (for example carbon fibers grown in the vapor phase or VGCF, which is the English acronym for “vapor grown carbon fiber”), present in the formulation of the Li-ion battery anode or cathode.
  • another carbonaceous conductive filler such as carbon black, carbon nanotubes or carbon fibers (for example carbon fibers grown in the vapor phase or VGCF, which is the English acronym for “vapor grown carbon fiber”)
  • said polymer entering into the composition of said composite mixture is a fluorinated polymer, such as for example polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), a water-soluble thickening polymer, such as for example carboxymethylcellulose, an elastomer polyolefin, such as for example a styrene-butadiene rubber, an acrylic resin or a mixture of several of these components, including a mixture of different fluorinated polymers.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • a water-soluble thickening polymer such as for example carboxymethylcellulose
  • an elastomer polyolefin such as for example a styrene-butadiene rubber
  • acrylic resin or a mixture of several of these components, including a mixture of different fluorinated polymers.
  • said fluorinated polymer present in component A contains in its chain at least one monomer chosen from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at the least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group.
  • the fluorinated polymer can be a homopolymer or a copolymer.
  • the copolymer can also include non-fluorinated monomers such as ethylene.
  • the fluoropolymer is a polymer comprising units derived from vinylidene fluoride, and is preferably chosen from polyvinylidene fluoride homopolymer and copolymers comprising units of vinylidene fluoride and units derived from at least another comonomer copolymerizable with vinylidene fluoride.
  • the fluorinated polymer present in component A is a homopolymer of vinylidene fluoride.
  • the fluoropolymer is a copolymer comprising vinylidene fluoride (VDF) units and units derived from one or more monomers.
  • VDF vinylidene fluoride
  • VDF copolymers can also include non-fluorinated monomers such as ethylene.
  • the mass content of the VDF units is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.
  • the fluoropolymer is functionalized in whole or in part, which allows it to improve the adhesion to metal.
  • the fluoropolymer comprises monomer units bearing at least one carboxylic acid or hydroxyl function.
  • the functional group bears a carboxylic acid function.
  • the monomer unit bearing at least one carboxylic acid function is chosen from acrylic acid, methacrylic acid, and acryloyloxy propylsuccinate.
  • the units carrying the carboxylic acid function also comprise a heteroatom chosen from oxygen, sulphur, nitrogen and phosphorus.
  • the functional group bears a hydroxyl function.
  • the monomer unit bearing at least one carboxylic acid function is chosen from hydroxyethyl(meth)acrylate,
  • the functional group content of the fluorinated polymer is at least 0.01% molar, preferably at least 0.1% molar, and at most 15% molar, preferably at most 10 % molar.
  • the fluorinated polymer present in component A can be a mixture of one or more polymers described above, for example a mixture of a PVDF homopolymer and at least one VDF copolymer, a mixture of at least two VDF, a mixture of a functionalized PVDF and a homopolymer PVDF or a mixture of a functionalized PVDF and a VDF copolymer.
  • component A can also comprise silicon.
  • the silicon comes from the recycling of the anode.
  • the recycled conductive carbon filler/polymer mixture has the following mass composition:
  • polyolefin such as polyethylene and/or polypropylene
  • the recycled conductive carbon filler/polymer mixture has the following mass composition:
  • polyolefin such as polyethylene and/or polypropylene
  • the mass ratio between the water-soluble thickener and the polyolefin elastomer varies from 1:9 to 9:1, and is preferably 1:4.
  • the graphite present in component A has a particle size, expressed as volume average diameter (Dv50), ranging from 1 to 40 mhi, preferably from 5 to 30 ⁇ m.
  • Dv50 volume average diameter
  • This parameter can be measured by laser granulometry.
  • component A comprising graphite having a particle size, expressed as volume average diameter (Dv50), smaller than the volume average diameter (Dv50) of the graphite constituting component B described below.
  • the second component of the bipolar plate composition according to the invention is graphite. It is the major component by weight of the composition, present at 50% or more.
  • the graphite constituting component B has a volume-average diameter (Dv50) ranging from 50 to 500 mhi, preferably from 75 to 150 mhi.
  • the third component of the bipolar plate composition according to the invention is a polymer acting as a binder.
  • Said polymer can be a polyolefin (for example: polyethylene or polypropylene), a fluorinated polymer (PVDF), polyphenylsulfone, polyethersulfone, a phenolic resin, a vinylester resin, an epoxy resin, or a liquid-crystal polymer.
  • said fluorinated polymer present in component C contains in its chain at least one monomer chosen from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at the least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group.
  • this monomer can be vinylidene fluoride.
  • the fluorinated polymer can be a homopolymer or a copolymer.
  • the copolymer can also include non-fluorinated monomers such as ethylene.
  • the fluoropolymer is a polymer comprising units derived from vinylidene fluoride, and is preferably chosen from polyvinylidene fluoride homopolymer and copolymers comprising units of vinylidene fluoride and units derived from at least another comonomer copolymerizable with vinylidene fluoride.
  • the fluorinated polymer present in component C is a homopolymer of vinylidene fluoride.
  • the fluoropolymer is a copolymer comprising vinylidene fluoride (VDF) units and units derived from one or more monomers.
  • VDF copolymers can also include non-fluorinated monomers such as ethylene.
  • the mass content of the VDF units is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.
  • the fluoropolymer is functionalized, in whole or in part, which allows it to improve the adhesion to metal.
  • the fluoropolymer comprises monomer units bearing at least one carboxylic acid or carboxylic acid anhydride function.
  • the function is introduced onto the fluorinated polymer by a chemical reaction which may be grafting or copolymerization of the fluorinated monomer with a monomer bearing at least one -COOH or carboxylic acid anhydride group and a vinyl function capable of copolymerizing with the fluorinated monomer , according to techniques well known to those skilled in the art.
  • unsaturated mono- and dicarboxylic acids having from 2 to 20 carbon atoms, and in particular from 4 to 10 carbon atoms, such as acrylic acids, methacrylic , maleic, fumaric, itaconic, citraconic, allyl
  • the units carrying the carboxylic acid function also comprise a heteroatom chosen from oxygen, sulphur, nitrogen and phosphorus.
  • the functional group content of the fluorinated polymer is at least 0.01% molar, preferably at least 0.1% molar, and at most 15% molar, preferably at most 10 % molar.
  • the fluorinated polymer present in component C can be a mixture of one or more polymers described above, for example a mixture of a PVDF homopolymer and at least one VDF copolymer, or a mixture of at least two VDF copolymers.
  • the mass composition of the bipolar plate implemented in the method according to the invention consists of:
  • the invention relates to a process for manufacturing the composition described above, said process comprising the following steps:
  • component A a composite mixture based on at least one carbonaceous conductive filler and polymer(s) (component A),
  • the process according to the invention comprises a step of mixing in the molten state component A with component C and component B. This step makes it possible to formulate an intimate mixture.
  • the powders are mixed in the dry state.
  • the mixing step is carried out in the molten state by extrusion, using for example a mixer or a twin-screw extruder.
  • the invention also relates to a bipolar plate composition manufactured using the method described above.
  • the invention also relates to a bipolar plate comprising the composition described above, in an agglomerated form.
  • a bipolar plate is a plate that separates elementary cells in fuel cells, electrolyzers and redox flow batteries. In general, it has the shape of a parallelepiped having a thickness of a few millimeters (typically between 0.2 and 6 mm) and comprises on each face a network of channels for the circulation of gases and fluids. Its functions are to supply the fuel cell with gaseous fuel, to evacuate the reaction products and to collect the electric current produced by the cell.
  • the invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:
  • the bipolar plate composition is subjected to injection molding in powder form.
  • the method according to the invention may also comprise an additional step of grinding this powder, for example by means of a disc mill.
  • compositions of the invention are particularly well suited to the manufacture of composite bipolar plates by the injection molding process.
  • the injection molding process consists of several steps. First, granules or powders are introduced into an extruder via a feed hopper. Once introduced, the material is routed into the barrel where it is simultaneously heated, sheared and conveyed to the mold by the extrusion screw. The material is temporarily held in the sheath and put under pressure before the injection phase. When the appropriate pressure is reached, the material is injected into a mold having the shape and dimensions of the desired final object, the temperature of the mold being regulated. The cycle time depends on the size of the parts and the solidification time of the polymer. the keeping the material under pressure once injected into the mold limits deformation and shrinkage after demoulding. To eject the parts, the mold parts separate, the core retracts, and the ejectors are pushed to lift the parts off the mold surface.
  • the parameters of the injection process are multiple: temperature of the material during the plasticizing step, injection speed, injection pressure of the material, time and pressure held in the mould, mold temperature.
  • the temperature profile applied along the extrusion screw can vary from 100° C. to 280° C. from the feed zone to the head. injection.
  • the mold temperature can vary from room temperature up to 280°C. Several mold cooling methods can be used.
  • the material can be injected into a mold maintained at a temperature between the melting and glass transition temperatures for a semi-crystalline polymer.
  • the temperature of the mold varies during the injection cycle.
  • the material is first injected into a mold whose temperature is higher than the melting temperature for a semi-crystalline thermoplastic polymer. This phase favors the filling of the mould.
  • the mold is cooled to a temperature between the melting and glass transition temperatures for a semi-crystalline polymer to promote crystallization.
  • Commercial versions of these variable mold temperature processes exist. Examples include Roctool, Variotherm and Variomelt technologies.
  • injection parameters such as injection speed, injection pressure of the material, time and holding pressure in the mold depend on the geometry of the mold, its dimensions, the size and position of the injection gates .
  • the invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:
  • the bipolar plate composition is subjected to compression molding in powder form.
  • the method according to the invention may also comprise a step of grinding this powder, for example by means of a disk mill.
  • the compression molding of compositions intended to produce bipolar plates can be carried out by introducing said composition into a mould, for example a stainless steel mould, which is then closed and heated to a temperature ranging from 200°C to 350°C, preferably from 250°C to 300°C. Then, a compression force of 300 t to 800 t, preferably 400 t to 600 t, is applied to the mold, for a mold with dimensions of 100,000 to 150,000 mm 2 . Typically, a compression force of 500 t is applied when the mold size is 130000 mm 2 and a compression force of 300 t is applied when the mold size is 44000 mm 2 . The mold is then cooled to a temperature of 50° C. to 120° C., preferably 60° C. to 100° C., and the plate is unmolded.
  • the invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:
  • composition - subjecting said composition to a continuous extrusion process.
  • the composition is introduced into a single-screw or twin-screw type extruder with a flat die, so as to obtain a continuous plate which is subsequently etched.
  • the invention further relates to the bipolar plates obtained by the methods described above.
  • the bipolar plate has at least one of the following characteristics, and preferably all of these characteristics:
  • thermal conductivity equal to or greater than 10 W/m/K
  • a flexural strength equal to or greater than 25 N/mm 2 ;
  • Bending strength is measured according to DIN EN ISO 178. Compressive strength is measured according to ISO 604. Thermal conductivity is measured using the Laser Llash technique according to DIN EN ISO 821. Surface resistivity is measured by means of probe samples at four points on crushed samples having a thickness of 4 mm. Volume resistivity is measured with a two-electrode installation and a contact pressure of 1 N/mm 2 on surfaced samples having a diameter of 13 mm and a thickness of 2 mm.
  • the bipolar plate has a surface resistivity equal to or less than 0.008 Ohm.cm, or equal to or less than 0.005 Ohm.cm, or equal to or less than 0.003 Ohm.cm, or equal to or less than 0.001 Ohm. cm.
  • the bipolar plate has a through resistivity equal to or less than 0.025 Ohm.cm, or equal to or less than 0.02 Ohm.cm, or equal to or less than 0.015 Ohm.cm.
  • the bipolar plate has a thermal conductivity equal to or greater than 15 W/m/K, or equal to or greater than 20 W/m/K.
  • the bipolar plate has a resistance to bending equal to or greater than 30 N/mm 2 , or equal to or greater than 35 N/mm 2 .
  • the bipolar plate consists of:
  • component B as defined in the present invention having an average volume diameter (Dv50) ranging from 50 to 500 mhi,
  • component A as defined in the present invention and comprising graphite having a particle size, expressed as volume average diameter (Dv50) ranging from 1 to 40 mhi, from 5 to 40% of component C as defined in the present invention; the sum of these percentages being 100%.
  • Dv50 volume average diameter
  • a synthetic graphite (Graphite Timrex KS150) having a particle size characterized by a Dv50 of 55mhi and a homopolymer of vinylidene difluoride which has a melt viscosity measured at 232°C and 100 s - 1 of 900 Pa.s were used.
  • Composition 1 from the recycling of a lithium-ion battery graphite anode
  • Composition 1 from a graphite anode was obtained by a recycling process based on the physical separation of the elements. First, the battery components (anode/separator/cathode) were physically separated. The anode was then crushed. Finally, it was subjected to an air jet sieving to separate the copper fragments, graphite and polymeric binders. At the end of this step, a powder consisting of 96.3% by weight of graphite, 3.4% by weight of carboxymethyl cellulose (CMC) and 2.6% by weight of a styrene and butadiene elastomer (SBR) was recovered. . The graphite in this composition was a synthetic graphite which has a particle size characterized by a Dv50 of 17 mhi.
  • CMC carboxymethyl cellulose
  • SBR styrene and butadiene elastomer
  • Composition 2 from the black mass of a Lithium-ion battery with graphite anode and NMC cathode: Composition 2 is from the black mass of a Lithium-ion battery. It contains the non-metallic and non-inorganic residues, i.e. the graphite, the conductive carbonaceous filler of the cathode, the polymer binders of the electrodes (PVDL, CMC, SBR) and the polyolefin of the separator. The constituent elements of the battery (anode/separator/cathode) were first shredded and then ground.
  • the ground material was subjected to the different stages of a hydrometallurgy process in order to dissolve the metallic current collectors and the inorganic fillers such as NMC and bohemite from the separator coating.
  • the residues from the hydrometallurgy process are composed of:
  • CMC carboxymethyl cellulose
  • SBR styrene and butadiene elastomer
  • PVDL polyvinylidene fluoride
  • composition of the bipolar plates with iso rate of binder iso rate of binder
  • Example 1 The constituents of Example 1, the Timrex KS150 graphite, the KynarÂź 721 PVDF and the composition resulting from the recycling of a lithium-ion battery anode, were pre-mixed using a twin-screw extruder . At the end of this mixing step, very friable granules were obtained. These granules were then ground using a disc mill to obtain a powder with an average size Dv50 of less than 500 mhi.
  • composition of the comparative example was prepared according to the same protocol.
  • the fabrication of the bipolar plates was carried out by thermocompression. To do this, a mold with a dimension of 30 ⁇ 30 cm 2 was manually filled with the composition in powder form. The powder was leveled manually with a metal blade. The mold was closed and brought to 240° C. under a pressure of 150 bars. The amount of powder was adjusted to obtain a thickness of approximately 3mm. The mold was cooled under pressure to a temperature of 80°C. Once this temperature was reached, the pressure was released and the plate was removed from the mould.
  • the bipolar plates according to the present invention have a better resistance to bending compared to the comparative example in which there is no graphite resulting from the recycling of a battery.

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Abstract

The present invention relates to a method for manufacturing a bipolar plate composition. The invention also relates to methods of manufacturing bipolar plates by injection, extrusion or compression, from said composition, as well as to the bipolar plates obtained by these methods.

Description

DESCRIPTION DESCRIPTION

TITRE : PROCEDE DE FABRICATION DE PLAOUES BIPOLAIRES TITLE: METHOD FOR MANUFACTURING BIPOLAR PLATES

DOMAINE TECHNIQUE TECHNICAL AREA

La prĂ©sente invention concerne un procĂ©dĂ© de fabrication d’une composition de plaque bipolaire. L’invention concerne Ă©galement des procĂ©dĂ©s de fabrication de plaques bipolaires par injection, extrusion ou compression, Ă  partir de ladite composition, ainsi que les plaques bipolaires obtenues par ces procĂ©dĂ©s. The present invention relates to a method of making a bipolar plate composition. The invention also relates to processes for manufacturing bipolar plates by injection, extrusion or compression, from said composition, as well as the bipolar plates obtained by these processes.

CONTEXTE TECHNIQUE TECHNICAL CONTEXT

Les plaques bipolaires sont utilisĂ©es dans les piles Ă  combustible, les Ă©lectrolyseurs et dans les batteries Ă  flux redox. Elles peuvent ĂȘtre rĂ©alisĂ©es Ă  partir de diffĂ©rents matĂ©riaux : plaques bipolaires mĂ©talliques, plaques en graphite et plaques en composites carbone - polymĂšre. Bipolar plates are used in fuel cells, electrolyzers and in redox flow batteries. They can be made from different materials: metallic bipolar plates, graphite plates and carbon-polymer composite plates.

Le principe des plaques bipolaires Ă  base de matĂ©riaux composites organiques repose sur l’utilisation de charges conductrices (carbone, graphite...) dispersĂ©es dans un polymĂšre thermoplastique ou thermodurcissable. Les charges vont confĂ©rer aux plaques bipolaires la conductivitĂ© Ă©lectrique nĂ©cessaire Ă  la collecte du courant et la matrice polymĂšre leur bonne tenue mĂ©canique nĂ©cessaire Ă  l’assemblage des diffĂ©rents Ă©lĂ©ments. The principle of bipolar plates based on organic composite materials is based on the use of conductive fillers (carbon, graphite, etc.) dispersed in a thermoplastic or thermosetting polymer. The fillers will give the bipolar plates the electrical conductivity necessary for collecting the current and the polymer matrix their good mechanical strength necessary for assembling the various elements.

Les plaques bipolaires composites carbone -polymÚre présentent des propriétés intéressantes : une haute conductivité électrique, une bonne résistance à la corrosion, de bonnes performances à haute température, et de bonnes propriétés mécaniques, avec un coût de fabrication relativement faible. Dans ces plaques bipolaires composites, un polymÚre thermodurcissable ou thermoplastique est utilisé comme matrice pour une charge carbonée choisie parmi le graphite, les fibres de carbone, le noir de carbone ou les nanotubes de carbone. Bien que la performance électrique des plaques bipolaires composites soit principalement déterminée par la charge carbonée, le matériau de la matrice polymÚre influence également le comportement électrique du composite. Carbon-polymer composite bipolar plates have interesting properties: high electrical conductivity, good corrosion resistance, good performance at high temperature, and good mechanical properties, with a relatively low manufacturing cost. In these composite bipolar plates, a thermosetting or thermoplastic polymer is used as a matrix for a carbonaceous filler chosen from among graphite, carbon fibers, carbon black or carbon nanotubes. Although the electrical performance of composite bipolar plates is mainly determined by the carbon charge, the material of the polymer matrix also influences the electrical behavior of the composite.

Les composites polymĂšres thermodurcissables - graphite sont des matĂ©riaux prĂ©fĂ©rĂ©s pour la fabrication de plaques bipolaires. Cependant, des matĂ©riaux composites Ă  base de polymĂšres thermoplastiques, notamment des thermoplastiques stables aux tempĂ©ratures Ă©levĂ©es, ont dĂ©jĂ  Ă©tĂ© utilisĂ©s dans la fabrication de plaques bipolaires, en raison de leur aptitude d’ĂȘtre moulĂ©s par injection ou extrudĂ©s, ce qui les rend plus aptes Ă  la fabrication automatisĂ©e. De tels composites ont Ă©tĂ© prĂ©parĂ©s en utilisant du sulfure de polyphĂ©nylĂšne (PPS) ou du polyĂ©ther sulfone (PES) contenant de la poudre de graphite, comme rapportĂ© par Radhakrishnan, S. et al. dans la publication : « High-temperature, Polymer-graphite Hybrid Composites for Bipolar Plates: Effect of Processing Conditions on Electrical Properties », Journal of Power Sources, 2006, Vol. 163, pp. 702-707. Thermosetting polymer-graphite composites are preferred materials for the fabrication of bipolar plates. However, composite materials based on thermoplastic polymers, in particular thermoplastics stable at high temperatures, have already been used in the manufacture of bipolar plates, in due to their ability to be injection molded or extruded, making them more suitable for automated manufacturing. Such composites have been prepared using polyphenylene sulfide (PPS) or polyether sulfone (PES) containing graphite powder, as reported by Radhakrishnan, S. et al. in the publication: “High-temperature, Polymer-graphite Hybrid Composites for Bipolar Plates: Effect of Processing Conditions on Electrical Properties”, Journal of Power Sources, 2006, Vol. 163, p. 702-707.

La publication de Mighri F. et al. “Electrically conductive thermoplastic blends for injection and compression molding of bipolar plates in the fuel cell application”, Polymer Engineering and Science, 2004, vol 44, n°9 dĂ©crit des plaques bipolaires faites par les procĂ©dĂ©s de compression et d’injection Ă  partir de graphite, de noir de carbone et de polypropylĂšne ou polysulfure de phĂ©nylĂšne. The publication by Mighri F. et al. “Electrically conductive thermoplastic blends for injection and compression molding of bipolar plates in the fuel cell application”, Polymer Engineering and Science, 2004, vol 44, n°9 describes bipolar plates made by compression and injection processes from graphite, carbon black and polypropylene or polyphenylene sulfide.

Les principales propriétés recherchées de plaques bipolaires pour piles à combustibles sont : des conductivités électronique et thermique élevées, de bonnes propriétés mécaniques comme les propriétés en flexion, et des propriétés barriÚres aux gaz élevées. The main desired properties of bipolar plates for fuel cells are: high electronic and thermal conductivities, good mechanical properties such as bending properties, and high gas barrier properties.

Il existe un besoin de fournir un procĂ©dĂ© de fabrication d’une composition pour plaque bipolaire, ladite composition prĂ©sentant un bon compromis entre ces propriĂ©tĂ©s, et ledit procĂ©dĂ© Ă©tant compatible avec les procĂ©dĂ©s de fabrication comme l’injection, la thermo-compression, ou l’extrusion. There is a need to provide a method for manufacturing a composition for a bipolar plate, said composition having a good compromise between these properties, and said method being compatible with manufacturing methods such as injection, thermo-compression, or 'extrusion.

RÉSUMÉ DE L’INVENTION SUMMARY OF THE INVENTION

Selon un premier aspect, l’invention concerne un procĂ©dĂ© de fabrication d’une composition pour plaque bipolaire, ledit procĂ©dĂ© comprenant les Ă©tapes suivantes: According to a first aspect, the invention relates to a method for manufacturing a composition for a bipolar plate, said method comprising the following steps:

- fournir un mĂ©lange composite Ă  base d’au moins une charge conductrice carbonĂ©e et de polymĂšre(s), - provide a composite mixture based on at least one carbonaceous conductive filler and polymer(s),

- incorporer audit mélange composite du graphite et un liant polymÚre. - incorporating said composite mixture of graphite and a polymer binder.

De maniÚre caractéristique, ledit mélange composite est issu du recyclage de batteries lithium-ion. Characteristically, said composite mixture comes from the recycling of lithium-ion batteries.

Selon un mode de réalisation, le recyclage de batteries lithium-ion est effectué par un procédé choisi parmi la séparation physique, la pyrométallurgie, G hydrométallurgie, ou une combinaison de ceux-ci. Préférentiellement, il est effectué un démantÚlement des différents composants de la cellule (cathode / anode / séparateur) avant leur broyage. According to one embodiment, the recycling of lithium-ion batteries is carried out by a process chosen from among physical separation, pyrometallurgy, hydrometallurgy, or a combination thereof. Preferably, the different components of the cell (cathode/anode/separator) are dismantled before they are ground.

Selon un mode de rĂ©alisation, ladite au moins une charge conductrice carbonĂ©e est du graphite utilisĂ© comme charge active Ă  l’anode de batterie lithium-ion. According to one embodiment, said at least one carbonaceous conductive filler is graphite used as active filler at the lithium-ion battery anode.

Selon un mode de rĂ©alisation, ladite charge conductrice carbonĂ©e est un mĂ©lange de graphite et d'une autre charge conductrice carbonĂ©e, comme le noir de carbone ou les nanotubes de carbone prĂ©sents dans la formulation de l’anode ou de la cathode de batterie Li-ion. According to one embodiment, said carbonaceous conductive filler is a mixture of graphite and another carbonaceous conductive filler, such as carbon black or carbon nanotubes present in the formulation of the Li-battery anode or cathode. ion.

Selon un mode de réalisation, ledit polymÚre entrant dans la composition dudit mélange composite est un polymÚre fluoré, un polymÚre épaississant hydrosoluble (comme par exemple la carboxyméthylcellulose), un élastomÚre polyoléfïne (comme par exemple un caoutchouc styrÚne -butadiÚne), une résine acrylique (comme par exemple des polymÚres acryliques carboxylées) ou un mélange de plusieurs de ces composants, y compris un mélange de polymÚres fluorés différents. According to one embodiment, said polymer entering into the composition of said composite mixture is a fluorinated polymer, a water-soluble thickening polymer (such as, for example, carboxymethylcellulose), a polyolefin elastomer (such as, for example, a styrene-butadiene rubber), an acrylic resin ( such as carboxylated acrylic polymers) or a mixture of several of these components, including a mixture of different fluoropolymers.

L’invention concerne, selon un autre aspect, un procĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: The invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:

- préparer une composition selon le procédé décrit ci-dessus, et - preparing a composition according to the process described above, and

- soumettre ladite composition Ă  un moulage par injection. - Subjecting said composition to injection molding.

L’invention concerne, selon un autre aspect, un procĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: The invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:

- préparer une composition selon le procédé décrit ci-dessus, et - preparing a composition according to the method described above, and

- soumettre ladite composition Ă  un moulage par compression. - Subjecting said composition to compression molding.

L’invention concerne, selon un autre aspect, un procĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: The invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:

- préparer une composition selon le procédé décrit ci-dessus, et - preparing a composition according to the method described above, and

- soumettre ladite composition Ă  un procĂ©dĂ© d’extrusion en continu. - subjecting said composition to a continuous extrusion process.

L’invention concerne en outre les plaques bipolaires obtenues par les procĂ©dĂ©s dĂ©crits ci-dessus ou comprenant la composition dĂ©crite ci-dessus. The invention further relates to the bipolar plates obtained by the methods described above or comprising the composition described above.

La prĂ©sente invention permet de surmonter les inconvĂ©nients de l’état de l’art. Elle fournit plus particuliĂšrement un procĂ©dĂ© de fabrication de compositions pouvant ĂȘtre mises en Ɠuvre facilement pour fabriquer des plaques bipolaires. Les avantages de cette approche mettant en Ɠuvre un mĂ©lange composite issu du recyclage de batteries lithium-ion, sont de bĂ©nĂ©ficier de la bonne dispersion du liant polymĂšre dans le mĂ©lange recyclĂ© charge carbonĂ©e conductrice/polymĂšre, ce qui permet d'amĂ©liorer la dispersion de la charge carbonĂ©e dans la plaque bipolaire. Ceci permet d'amĂ©liorer la rĂ©sistance mĂ©canique, les propriĂ©tĂ©s barriĂšres aux gaz et la conductivitĂ©. The present invention makes it possible to overcome the disadvantages of the state of the art. It more particularly provides a process for the manufacture of compositions which can be implemented easily to manufacture bipolar plates. The advantages of this approach using a composite mixture resulting from the recycling of lithium-ion batteries, are to benefit from the good dispersion of the polymer binder in the recycled conductive carbon filler/polymer mixture, which makes it possible to improve the dispersion of the carbon charge in the bipolar plate. This makes it possible to improve the mechanical resistance, the gas barrier properties and the conductivity.

Dans le cas de la fabrication d’une plaque bipolaire par un procĂ©dĂ© nĂ©cessitant une faible viscositĂ© (injection) du mĂ©lange polymĂšre - graphite, un autre avantage provient de la diffĂ©rence de taille de particules entre le graphite utilisĂ© pour la plaque bipolaire et le graphite utilisĂ© dans une anode de batterie Li-ion. Le premier est plus gros (ayant typiquement un diamĂštre moyen en volume (Dv50) allant de 50 Ă  150 mhi) que le second (ayant typiquement un Dv50 autour de 20 mhi et infĂ©rieur Ă  40 mhi). Cette diffĂ©rence permet d’amĂ©liorer la conductivitĂ© Ă©lectrique transverse grĂące aux plus petites particules de graphite qui viennent s'insĂ©rer dans les interstices laissĂ©s par les plus grosses particules de graphite, tout en limitant la viscosification du mĂ©lange, confĂ©rant une bonne mise en Ɠuvre de la plaque bipolaire Ă  celui-ci. In the case of the manufacture of a bipolar plate by a process requiring a low viscosity (injection) of the polymer-graphite mixture, another advantage comes from the difference in particle size between the graphite used for the bipolar plate and the graphite used in a Li-ion battery anode. The first is larger (typically having a volume average diameter (Dv50) ranging from 50 to 150 mhi) than the second (typically having a Dv50 around 20 mhi and less than 40 mhi). This difference makes it possible to improve the transverse electrical conductivity thanks to the smallest particles of graphite which are inserted into the interstices left by the largest particles of graphite, while limiting the viscosity of the mixture, conferring a good implementation of the bipolar plate to this one.

Par ailleurs, le fait que le graphite recyclĂ© ait connu une premiĂšre vie dans une batterie lui a permis d’ĂȘtre recouvert par une interface d’électrolyte solide (« SEI » pour « solid electrolyte interface »). Cette couche de SEI est composĂ©e d’élĂ©ments inorganiques (LiL, L12O2, L12CO3) et Ă©galement de fractions de polymĂšres issues de la dĂ©composition des solvants d’électrolytes. Par consĂ©quent, cette couche de SEI participe d’une meilleure flexibilitĂ© et rĂ©sistance aux fissures, confĂ©rant au graphite recyclĂ© la capacitĂ© d’amĂ©liorer les propriĂ©tĂ©s mĂ©caniques de la plaque bipolaire. In addition, the fact that recycled graphite had a first life in a battery allowed it to be covered by a solid electrolyte interface (“SEI” for “solid electrolyte interface”). This layer of SEI is composed of inorganic elements (LiL, L12O2, L12CO3) and also of polymer fractions resulting from the decomposition of electrolyte solvents. Consequently, this layer of SEI contributes to better flexibility and resistance to cracks, giving the recycled graphite the ability to improve the mechanical properties of the bipolar plate.

DESCRIPTION DE MODES DE RÉALISATION DE L’INVENTION DESCRIPTION OF EMBODIMENTS OF THE INVENTION

L’invention est dĂ©crite de maniĂšre dĂ©taillĂ©e ci-aprĂšs. The invention is described in detail below.

Les pourcentages indiqués dans le texte sont des pourcentages massiques. The percentages indicated in the text are mass percentages.

L’invention a pour objet l’utilisation d’un mĂ©lange charges conductrices/polymĂšres issu du recyclage des batteries lithium-ion pour la fabrication de plaques bipolaires. The subject of the invention is the use of a mixture of conductive fillers/polymers resulting from the recycling of lithium-ion batteries for the manufacture of bipolar plates.

Selon un premier aspect, l’invention concerne un procĂ©dĂ© de fabrication d’une composition pour plaque bipolaire, ledit procĂ©dĂ© comprenant les Ă©tapes suivantes: - fournir un mĂ©lange composite Ă  base d’au moins une charge conductrice carbonĂ©e et de polymĂšre(s) (composant A), According to a first aspect, the invention relates to a method for manufacturing a composition for a bipolar plate, said method comprising the following steps: - providing a composite mixture based on at least one carbonaceous conductive filler and polymer(s) (component A),

- incorporer audit mélange composite du graphite (composant B) et un liant polymÚre (composant C), caractérisé en ce que ledit mélange composite est issu du recyclage de batteries lithium- ion. - incorporating into said composite mixture graphite (component B) and a polymer binder (component C), characterized in that said composite mixture comes from the recycling of lithium-ion batteries.

Selon diverses réalisations, ledit procédé comprend les caractÚres suivants, le cas échéant combinés. According to various embodiments, said method comprises the following characters, possibly combined.

Composant A Component A

Selon un mode de réalisation, ledit mélange composite est préparé par un procédé recyclage de batteries lithium-ion choisi parmi la pyrométallurgie, G hydrométallurgie, la séparation physique basée sur des caractéristiques des matériaux telles que la granulométrie, la densité, les propriétés magnétiques ou électriques, telle que la flottation, ou leur combinaison. According to one embodiment, said composite mixture is prepared by a lithium-ion battery recycling process chosen from among pyrometallurgy, hydrometallurgy, physical separation based on characteristics of the materials such as particle size, density, magnetic or electrical properties , such as flotation, or a combination thereof.

La batterie à recycler est démantelée afin de récupérer les polymÚres, les charges carbonées et les métaux nobles des électrodes. Avantageusement, les batteries qui sont recyclées sont celles ayant une cathode NMC (nickel-manganÚse-cobalt) ou NCA (nickel- cobalt-aluminium) et une anode en graphite. The battery to be recycled is dismantled in order to recover the polymers, carbonaceous fillers and noble metals from the electrodes. Advantageously, the batteries which are recycled are those having an NMC (nickel-manganese-cobalt) or NCA (nickel-cobalt-aluminum) cathode and a graphite anode.

Selon un mode de rĂ©alisation, on sĂ©pare physiquement les composants d’une batterie lithium-ion : cathode/sĂ©parateur/anode, on effectue un broyage de la cathode et de l’anode, puis on effectue les Ă©tapes d’hydromĂ©tallurgie pour rĂ©cupĂ©rer sĂ©lectivement des matĂ©riaux, notamment le cobalt et nickel. Les rĂ©sidus d’hydromĂ©tallurgie sont constituĂ©s des charges carbonĂ©es conductrices et des polymĂšres comme le PVDF rĂ©sistant aux Ă©tapes de lixiviation et reprĂ©cipitation, et pouvant donc ĂȘtre rĂ©utilisĂ©s selon la prĂ©sente invention. According to one embodiment, the components of a lithium-ion battery are physically separated: cathode/separator/anode, the cathode and the anode are ground, then the hydrometallurgy steps are carried out to selectively recover materials, including cobalt and nickel. Hydrometallurgy residues consist of conductive carbonaceous fillers and polymers such as PVDF that are resistant to leaching and reprecipitation stages, and can therefore be reused according to the present invention.

Selon un autre mode de rĂ©alisation, on sĂ©pare physiquement les composants d’une batterie lithium-ion : cathode/sĂ©parateur/anode, on effectue un broyage de la cathode et de l’anode puis on effectue une flottation ou un tamisage Ă  jet d’air permettant de rĂ©cupĂ©rer les charges carbonĂ©es conductrices et les liants polymĂšres peu denses et hydrophobes, ainsi sĂ©parĂ©s des charges actives mĂ©talliques et des rĂ©sidus de collecteurs de courants mĂ©talliques plus denses. Le procĂ©dĂ© de recyclage amĂšne Ă  rĂ©cupĂ©rer les charges carbonĂ©es qui sont associĂ©es Ă  des polymĂšres thermoplastiques, c’est-Ă -dire les liants des Ă©lectrodes. En fonction de l’aspect du mĂ©lange recyclĂ© composite charges carbonĂ©es conductrices/polymĂšre (Ă©cailles, poudre grossiĂšre), le procĂ©dĂ© selon l’invention peut comprendre une Ă©tape prĂ©alable qui consiste Ă  broyer, redisperser et tamiser ledit mĂ©lange afin d’obtenir une poudre ayant une taille de particules de 500 qrn maximum, prĂ©fĂ©rentiellement infĂ©rieure Ă  200 um. According to another embodiment, the components of a lithium-ion battery are physically separated: cathode/separator/anode, the cathode and the anode are ground and then flotation or jet sieving is carried out. air allowing to recover the conductive carbonaceous fillers and the sparse and hydrophobic polymer binders, thus separated from the metallic active fillers and the denser metallic current collector residues. The recycling process leads to the recovery of the carbonaceous fillers which are associated with thermoplastic polymers, that is to say the binders of the electrodes. Depending on the appearance of the composite recycled conductive carbonaceous filler/polymer mixture (scales, coarse powder), the method according to the invention may comprise a preliminary step which consists in grinding, redispersing and sieving said mixture in order to obtain a powder having a particle size of 500 ”m maximum, preferably less than 200 ”m.

Selon un mode de rĂ©alisation, dans le cas oĂč l’on a prĂ©alablement effectuĂ© un dĂ©mantĂšlement physique avec une sĂ©paration cathode / sĂ©parateur / anode, on procĂšde Ă  une recombinaison des poudres charges carbonĂ©es conductrices/polymĂšres issues de la cathode et de l’anode par un procĂ©dĂ© de mĂ©lange de poudres Ă  l’état sec avec un Ă©quipement tel qu’un mĂ©langeur Ă  rubans ou Ă  pĂąles. Il est possible de rĂ©aliser cete recombinaison Ă  l’état fondu par un procĂ©dĂ© d’extrusion permettant d’obtenir des Ă©cailles ou granulĂ©s friables qui doivent ĂȘtre ensuite rebroyĂ©s. According to one embodiment, in the case where a physical dismantling has been carried out beforehand with a cathode/separator/anode separation, a recombination of the conductive carbonaceous filler powders/polymers from the cathode and the anode is carried out by a method of mixing dry powders with equipment such as a ribbon or paddle mixer. It is possible to carry out this recombination in the molten state by an extrusion process making it possible to obtain flakes or friable granules which must then be reground.

Selon un mode de rĂ©alisation, on broie la cellule ou le module sans procĂ©der Ă  un dĂ©mantĂšlement prĂ©alable. On peut alors rĂ©cupĂ©rer un mĂ©lange de charges conductrices carbonĂ©es et polymĂšres soit aprĂšs une ou des Ă©tape(s) de sĂ©paration physique comme dĂ©crit prĂ©cĂ©demment, soit comme rĂ©sidu de procĂ©dĂ© d’hydromĂ©tallurgie According to one embodiment, the cell or the module is ground without carrying out any prior dismantling. It is then possible to recover a mixture of carbonaceous and polymeric conductive fillers either after one or more physical separation step(s) as described above, or as a residue from the hydrometallurgy process.

Selon un mode de rĂ©alisation, une Ă©tape de pyromĂ©tallurgie est effectuĂ©e pour Ă©liminer les polymĂšres prĂ©sents. Seules les charges carbonĂ©es conductrices sont alors rĂ©cupĂ©rĂ©es pour ĂȘtre utilisĂ©es selon l’invention. According to one embodiment, a pyrometallurgy step is carried out to eliminate the polymers present. Only the conductive carbonaceous fillers are then recovered to be used according to the invention.

Selon un mode de rĂ©alisation, ladite au moins une charge conductrice carbonĂ©e est du graphite utilisĂ© comme charge active Ă  l’anode de batterie lithium-ion. According to one embodiment, said at least one carbonaceous conductive filler is graphite used as active filler at the lithium-ion battery anode.

Selon un mode de rĂ©alisation, ladite charge conductrice carbonĂ©e est un mĂ©lange de graphite et d'une autre charge conductrice carbonĂ©e, comme le noir de carbone, les nanotubes de carbone ou les fibres de carbone (par exemple les fibres de carbone dĂ©veloppĂ©es en phase vapeur ou VGCF, qui est l’acronyme anglais pour « vapor grown carbon fĂŻber »), prĂ©sents dans la formulation de l’anode ou de la cathode de batterie Li- ion. According to one embodiment, said carbonaceous conductive filler is a mixture of graphite and another carbonaceous conductive filler, such as carbon black, carbon nanotubes or carbon fibers (for example carbon fibers grown in the vapor phase or VGCF, which is the English acronym for “vapor grown carbon fiber”), present in the formulation of the Li-ion battery anode or cathode.

Selon un mode de réalisation, ledit polymÚre entrant dans la composition dudit mélange composite est un polymÚre fluoré, comme par exemple le polyfluorure de vinylidÚne (PVDF) ou le polytétrafluoroéthylÚne (PTFE), un polymÚre épaississant hydrosoluble, comme par exemple la carboxyméthylcellulose, un élastomÚre polyoléfïne, comme par exemple un caoutchouc styrÚne-butadiÚne, une résine acrylique ou un mélange de plusieurs de ces composants, y compris un mélange de polymÚres fluorés différents. Selon un mode de réalisation, ledit polymÚre fluoré présent dans le composant A contient dans sa chaßne au moins un monomÚre choisi parmi les composés contenant un groupe vinyle capable de s'ouvrir pour se polymériser et qui contient, directement attaché à ce groupe vinyle, au moins un atome de fluor, un groupe fluoroalkyle ou un groupe fluoroalkoxy. According to one embodiment, said polymer entering into the composition of said composite mixture is a fluorinated polymer, such as for example polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), a water-soluble thickening polymer, such as for example carboxymethylcellulose, an elastomer polyolefin, such as for example a styrene-butadiene rubber, an acrylic resin or a mixture of several of these components, including a mixture of different fluorinated polymers. According to one embodiment, said fluorinated polymer present in component A contains in its chain at least one monomer chosen from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at the least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group.

Selon un mode de rĂ©alisation, ce monomĂšre peut ĂȘtre le fluorure de vinyle, le fluorure de vinylidĂšne, le trifluoroĂ©thylĂšne, le chlorotrifluoroĂ©thylĂšne, le 1,2- difluoroĂ©thylĂšne, le tĂ©trafluoroĂ©thylĂšne, l’hexafluoropropylĂšne ; des perfluoro(alkyl vinyl) Ă©thers tels que perfluoro(mĂ©thyl vinyl)Ă©ther, perfluoro(Ă©thyl vinyl) Ă©ther or perfluoro(propyl vinyl) Ă©ther; perfluoro(l,3-dioxole); perfluoro(2,2-dimĂ©thyl-l,3- dioxole) ; le produit de formule CF2=CFOCF2CF(CF3)OCF2CF2X dans lequelle X est SO2F, CO2H, CH2OH, CH2OCN ou CH2OPO3H; le produit de formule CF2=CF0CF2CF2S02F; le produit de formule F(CF2)nCH20CF=CF2 dans laquelle n est 1, 2, 3, 4 ou 5; le produit de formule RICH20CF=CF2 dans laquelle Ri est hydrogĂšne ou F(CF2)m et m est 1, 2, 3 ou 4; le produit de formule R20CF=CH2 dans laquelle R2 est F(CF2)P et p est 1, 2, 3 ou 4; perfluorobutyl Ă©thylĂšne; 3,3,3-trifluoropropĂšne ou 2- trifluoromĂ©thyl-3 ,3 ,3-trifluoro- 1 -propĂšne. According to one embodiment, this monomer can be vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene; perfluoro(alkyl vinyl) ethers such as perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether or perfluoro(propyl vinyl) ether; perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole); the product of formula CF2=CFOCF2CF(CF3)OCF2CF2X wherein X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF2=CF0CF2CF2S02F; the product of formula F(CF2)nCH2OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula RICH20CF=CF2 in which R1 is hydrogen or F(CF2)m and m is 1, 2, 3 or 4; the product of formula R20CF=CH2 wherein R2 is F(CF2) P and p is 1, 2, 3 or 4; perfluorobutyl ethylene; 3,3,3-trifluoropropene or 2-trifluoromethyl-3,3,3-trifluoro-1-propene.

Le polymĂšre fluorĂ© peut ĂȘtre un homopolymĂšre ou un copolymĂšre. Le copolymĂšre peut Ă©galement comprendre des monomĂšres non-fluorĂ©s tel que l’éthylĂšne. The fluorinated polymer can be a homopolymer or a copolymer. The copolymer can also include non-fluorinated monomers such as ethylene.

Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© est un polymĂšre comprenant des motifs issus du fluorure de vinylidĂšne, et de prĂ©fĂ©rence est choisi parmi le polyfluorure de vinylidĂšne homopolymĂšre et les copolymĂšres comprenant des motifs de fluorure de vinylidĂšne et des motifs issus d’au moins un autre comonomĂšre copolymĂ©risable avec le fluorure de vinylidĂšne. According to one embodiment, the fluoropolymer is a polymer comprising units derived from vinylidene fluoride, and is preferably chosen from polyvinylidene fluoride homopolymer and copolymers comprising units of vinylidene fluoride and units derived from at least another comonomer copolymerizable with vinylidene fluoride.

Selon un mode de réalisation, le polymÚre fluoré présent dans le composant A est un homopolymÚre de fluorure de vinylidÚne. According to one embodiment, the fluorinated polymer present in component A is a homopolymer of vinylidene fluoride.

Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© est un copolymĂšre comprenant des unitĂ©s de fluorure de vinylidĂšne (VDF) et des unitĂ©s issues d’un ou plusieurs monomĂšres. Ces autres monomĂšres sont choisis dans la liste : fluorure de vinyle; trifluoroĂ©thylĂšne; chlorotrifluoroĂ©thylĂšne; 1 ,2-difluoroĂ©thylĂšne, tĂ©trafluoroĂ©thylĂšne; hexafluoropropylĂšne; perfluoro(alkyl vinyl)Ă©thers tels que le perfluoro(mĂ©thyl vinyl)Ă©ther, perfluoro(Ă©thyl vinyl)Ă©ther ou perfluoro(propyl vinyl)Ă©ther; perfluoro(l,3- dioxole); perfluoro(2,2-dimĂ©thyl-l,3-dioxole); le produit de formule CF2=CFOCF2CF(CF3)OCF2CF2X dans laquelle X est S02F, CO2H, CH2OH, CH2OCN ou CH2OPO3H; le produit de formule CF2=CF0CF2CF2S02F; le produit de formule F(CF2)nCH2OCF=CF2 dans laquelle n est 1, 2, 3, 4 ou 5; le produit de formule R’CH20CF=CF2 dans laquelle R’ est hydrogĂšne ou F(CF2)z et z est 1, 2, 3 ou 4; le produit de formule R”OCF=CH2 dans laquelle R” est F(CF2)z et z est 1, 2, 3 ou 4; perfluorobutylĂ©thylĂšne; 3,3,3-trifluoropropĂšne ou 2-trifhroromĂ©thyl-3,3,3-trifluoro-l- propĂšne. According to one embodiment, the fluoropolymer is a copolymer comprising vinylidene fluoride (VDF) units and units derived from one or more monomers. These other monomers are selected from the list: vinyl fluoride; trifluoroethylene; chlorotrifluoroethylene; 1,2-difluoroethylene, tetrafluoroethylene; hexafluoropropylene; perfluoro(alkyl vinyl)ethers such as perfluoro(methyl vinyl)ether, perfluoro(ethyl vinyl)ether or perfluoro(propyl vinyl)ether; perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole); the formula product CF2=CFOCF 2 CF(CF 3 )OCF2CF 2 X wherein X is S0 2 F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF 2 =CF0CF2CF 2 S02F; the product of formula F(CF 2 )nCH 2 OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula R'CH20CF=CF 2 in which R' is hydrogen or F(CF 2 )z and z is 1, 2, 3 or 4; the product of formula R”OCF=CH 2 in which R” is F(CF 2 )z and z is 1, 2, 3 or 4; perfluorobutylethylene; 3,3,3-trifluoropropene or 2-trifluoromethyl-3,3,3-trifluoro-1-propene.

Parmi ces comonomĂšres du VDF, l’hexafluoropropylĂšne est prĂ©fĂ©rĂ©. Les copolymĂšres de VDF peuvent Ă©galement comprendre des monomĂšres non-fluorĂ©s tel que l’éthylĂšne. Of these VDF comonomers, hexafluoropropylene is preferred. VDF copolymers can also include non-fluorinated monomers such as ethylene.

Dans les copolymĂšres de VDF, le taux massique des unitĂ©s VDF est d’au moins 50%, de prĂ©fĂ©rence au moins 60%, plus prĂ©fĂ©rablement supĂ©rieur Ă  70% et avantageusement supĂ©rieur Ă  80%. In the VDF copolymers, the mass content of the VDF units is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.

Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© est fonctionnalisĂ© en tout ou partie, ce qui lui permet d’amĂ©liorer l’adhĂ©sion sur du mĂ©tal. Dans ce cas, le polymĂšre fluorĂ© comprend des unitĂ©s monomĂšres portant au moins une fonction acide carboxylique ou hydroxyle. According to one embodiment, the fluoropolymer is functionalized in whole or in part, which allows it to improve the adhesion to metal. In this case, the fluoropolymer comprises monomer units bearing at least one carboxylic acid or hydroxyl function.

Selon un mode de rĂ©alisation, le groupement fonctionnel est porteur d’une fonction acide carboxylique. Dans ce cas, l’unitĂ© monomĂšre portant au moins une fonction acide carboxylique est choisie parmi l’acide acrylique, l’acide mĂ©thacrylique, et l’acryloyloxy propylsuccinate. According to one embodiment, the functional group bears a carboxylic acid function. In this case, the monomer unit bearing at least one carboxylic acid function is chosen from acrylic acid, methacrylic acid, and acryloyloxy propylsuccinate.

Selon un mode de rĂ©alisation, les unitĂ©s portant la fonction acide carboxylique comprennent en outre un hĂ©tĂ©roatome choisi parmi l’oxygĂšne, le soufre, l’azote et le phosphore. According to one embodiment, the units carrying the carboxylic acid function also comprise a heteroatom chosen from oxygen, sulphur, nitrogen and phosphorus.

Selon un mode de rĂ©alisation, le groupement fonctionnel est porteur d’une fonction hydroxyle. Dans ce cas, l’unitĂ© monomĂšre portant au moins une fonction acide carboxylique est choisie parmi l’hydroxyĂ©thyl(mĂ©th)acrylate,According to one embodiment, the functional group bears a hydroxyl function. In this case, the monomer unit bearing at least one carboxylic acid function is chosen from hydroxyethyl(meth)acrylate,

1 ’ hydroxypropyl(mĂ©th)acrylate et 1 ’ hydroxyĂ©thylhexyl(mĂ©th)acrylate. 1 ' hydroxypropyl (meth) acrylate and 1 ' hydroxyethylhexyl (meth) acrylate.

Selon un mode de rĂ©alisation, la teneur en groupes fonctionnels du polymĂšre fluorĂ© est d’au moins 0,01% molaire, de prĂ©fĂ©rence d’au moins 0,1 % molaire, et au plus de 15% molaire, de prĂ©fĂ©rence au plus 10% molaire. Le polymĂšre fluorĂ© prĂ©sent dans le composant A peut ĂȘtre un mĂ©lange d’un ou plusieurs polymĂšres dĂ©crits ci-dessus, par exemple un mĂ©lange d’un PVDF homopolymĂšre et d’au moins un copolymĂšre de VDF, un mĂ©lange d’au moins deux copolymĂšres de VDF, un mĂ©lange d’un PVDF fonctionnalisĂ© et d’un PVDF homopolymĂšre ou un mĂ©lange d’un PVDF fonctionnalisĂ© et d’un copolymĂšre de VDF. According to one embodiment, the functional group content of the fluorinated polymer is at least 0.01% molar, preferably at least 0.1% molar, and at most 15% molar, preferably at most 10 % molar. The fluorinated polymer present in component A can be a mixture of one or more polymers described above, for example a mixture of a PVDF homopolymer and at least one VDF copolymer, a mixture of at least two VDF, a mixture of a functionalized PVDF and a homopolymer PVDF or a mixture of a functionalized PVDF and a VDF copolymer.

Selon un mode de rĂ©alisation prĂ©fĂ©rĂ©, le composant A peut Ă©galement comprendre du silicium. De prĂ©fĂ©rence, le silicium est issu du recyclage de l’anode. According to a preferred embodiment, component A can also comprise silicon. Preferably, the silicon comes from the recycling of the anode.

Selon un mode de réalisation, le mélange recyclé charge carbonée conductrice /polymÚre présente la composition massique suivante : According to one embodiment, the recycled conductive carbon filler/polymer mixture has the following mass composition:

- 60 Ă  100% de graphite, - 60 to 100% graphite,

- 0 Ă  20% de silicium - 0 to 20% silicon

- 0 Ă  10% d’ Ă©paississant hydrosoluble, - 0 to 10% water-soluble thickener,

- 0 Ă  10% d’élastomĂšre polyolĂ©fĂŻne, - 0 to 10% polyolefin elastomer,

- 0 à 10% de résine acrylique, - 0 to 10% acrylic resin,

- 0 à 10% de polymÚre(s) fluoré(s), - 0 to 10% fluorinated polymer(s),

- 0 à 40% de polyoléfïne (telle que polyéthylÚne et/ou polypropylÚne) - 0 to 40% polyolefin (such as polyethylene and/or polypropylene)

- 0 à 10% d'une seconde charge conductrice carbonée, la somme de tous ces pourcentages étant de 100%. - 0 to 10% of a second carbonaceous conductive filler, the sum of all these percentages being 100%.

Selon un mode de réalisation, le mélange recyclé charge carbonée conductrice /polymÚre présente la composition massique suivante : According to one embodiment, the recycled conductive carbon filler/polymer mixture has the following mass composition:

- 70 Ă  100% de graphite, - 70 to 100% graphite,

- 0 Ă  10% d’ Ă©paississant hydrosoluble, - 0 to 10% water-soluble thickener,

- 0 Ă  10% d’élastomĂšre polyolĂ©fĂŻne, - 0 to 10% polyolefin elastomer,

- 0 à 10% de résine acrylique, - 0 to 10% acrylic resin,

- 0 à 10% de polymÚre(s) fluoré(s), - 0 to 10% fluorinated polymer(s),

- 0 à 40% de polyoléfïne (telle que polyéthylÚne et/ou polypropylÚne) - 0 to 40% polyolefin (such as polyethylene and/or polypropylene)

- 0 à 10% d'une seconde charge conductrice carbonée, la somme de tous ces pourcentages étant de 100%. - 0 to 10% of a second carbonaceous conductive filler, the sum of all these percentages being 100%.

Selon un mode de rĂ©alisation, le ratio massique entre l’épaississant hydrosoluble et l’élastomĂšre polyolĂ©fĂŻne varie de 1:9 Ă  9:1, et est de prĂ©fĂ©rence de 1 :4. According to one embodiment, the mass ratio between the water-soluble thickener and the polyolefin elastomer varies from 1:9 to 9:1, and is preferably 1:4.

Avantageusement, le graphite prĂ©sent dans le composant A prĂ©sente une taille de particules, exprimĂ©e en diamĂštre moyen en volume (Dv50) allant de 1 Ă  40 mhi, prĂ©fĂ©rentiellement de 5 Ă  30um. Le Dv50 est le diamĂštre des particules au cinquantiĂšme percentile de la distribution des tailles cumulative des particules. Ce paramĂštre peut ĂȘtre mesurĂ© par granulomĂ©trie laser. Advantageously, the graphite present in component A has a particle size, expressed as volume average diameter (Dv50), ranging from 1 to 40 mhi, preferably from 5 to 30 ÎŒm. The Dv50 is the diameter of the particles to the fiftieth percentile of the cumulative particle size distribution. This parameter can be measured by laser granulometry.

De préférence, le composant A comprenant du graphite ayant une taille de particules, exprimée en diamÚtre moyen en volume (Dv50), inférieure au diamÚtre moyen en volume (Dv50) du graphite constituant le composant B décrit ci-dessous. Preferably, component A comprising graphite having a particle size, expressed as volume average diameter (Dv50), smaller than the volume average diameter (Dv50) of the graphite constituting component B described below.

Composant B Component B

Le deuxiĂšme composant de la composition de plaque bipolaire selon l’invention est le graphite. C’est le composant majoritaire en poids de la composition, prĂ©sent Ă  50% ou plus. Avantageusement, le graphite constituant le composant B a un diamĂštre moyen en volume (Dv50) allant de 50 Ă  500 mhi, prĂ©fĂ©rentiellement de 75 Ă  150 mhi. The second component of the bipolar plate composition according to the invention is graphite. It is the major component by weight of the composition, present at 50% or more. Advantageously, the graphite constituting component B has a volume-average diameter (Dv50) ranging from 50 to 500 mhi, preferably from 75 to 150 mhi.

Composant C Component C

Le troisiĂšme composant de la composition de plaque bipolaire selon l’invention est un polymĂšre jouant le rĂŽle de liant. Ledit polymĂšre peut ĂȘtre une polyolĂ©fine (par exemple : polyĂ©thylĂšne ou polypropylĂšne), un polymĂšre fluorĂ© (PVDF), le polyphĂ©nylsulfone, le polyĂ©thersulfone, une rĂ©sine phĂ©nolique, une rĂ©sine vinylester, une rĂ©sine Ă©poxyde, ou un polymĂšre cristal-liquide. The third component of the bipolar plate composition according to the invention is a polymer acting as a binder. Said polymer can be a polyolefin (for example: polyethylene or polypropylene), a fluorinated polymer (PVDF), polyphenylsulfone, polyethersulfone, a phenolic resin, a vinylester resin, an epoxy resin, or a liquid-crystal polymer.

Selon un mode de réalisation, ledit polymÚre fluoré présent dans le composant C contient dans sa chaßne au moins un monomÚre choisi parmi les composés contenant un groupe vinyle capable de s'ouvrir pour se polymériser et qui contient, directement attaché à ce groupe vinyle, au moins un atome de fluor, un groupe fluoroalkyle ou un groupe fluoroalkoxy. According to one embodiment, said fluorinated polymer present in component C contains in its chain at least one monomer chosen from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at the least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group.

Selon un mode de rĂ©alisation, ce monomĂšre peut ĂȘtre le fluorure de vinylidĂšne.According to one embodiment, this monomer can be vinylidene fluoride.

Le polymĂšre fluorĂ© peut ĂȘtre un homopolymĂšre ou un copolymĂšre. Le copolymĂšre peut Ă©galement comprendre des monomĂšres non-fluorĂ©s tel que l’éthylĂšne. The fluorinated polymer can be a homopolymer or a copolymer. The copolymer can also include non-fluorinated monomers such as ethylene.

Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© est un polymĂšre comprenant des motifs issus du fluorure de vinylidĂšne, et de prĂ©fĂ©rence est choisi parmi le polyfluorure de vinylidĂšne homopolymĂšre et les copolymĂšres comprenant des motifs de fluorure de vinylidĂšne et des motifs issus d’au moins un autre comonomĂšre copolymĂ©risable avec le fluorure de vinylidĂšne. According to one embodiment, the fluoropolymer is a polymer comprising units derived from vinylidene fluoride, and is preferably chosen from polyvinylidene fluoride homopolymer and copolymers comprising units of vinylidene fluoride and units derived from at least another comonomer copolymerizable with vinylidene fluoride.

Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© prĂ©sent dans le composant C est un homopolymĂšre de fluorure de vinylidĂšne. Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© est un copolymĂšre comprenant des unitĂ©s de fluorure de vinylidĂšne (VDF) et des unitĂ©s issues d’un ou plusieurs monomĂšres. Ces autres monomĂšres sont choisis dans la liste : fluorure de vinyle; trifluoroĂ©thylĂšne; chlorotrifluoroĂ©thylĂšne; 1 ,2-difluoroĂ©thylĂšne, tĂ©trafluoroĂ©thylĂšne; hexafluoropropylĂšne; perfluoro(alkyl vinyl)Ă©thers tels que le perfluoro(mĂ©thyl vinyl)Ă©ther, perfluoro(Ă©thyl vinyl)Ă©ther ou perfluoro(propyl vinyl)Ă©ther; perfluoro(l,3- dioxole); perfluoro(2,2-dimĂ©thyl-l,3-dioxole); le produit de formule CF2=CFOCF2CF(CF3)OCF2CF2X dans laquelle X est SO2F, CO2H, CH2OH, CH2OCN ou CH2OPO3H; le produit de formule CF2=CF0CF2CF2S02F; le produit de formule F(CF2)nCH2OCF=CF2 dans laquelle n est 1, 2, 3, 4 ou 5; le produit de formule R’CH2OCF=CF2 dans laquelle R’ est hydrogĂšne ou F(CF2)z et z est 1, 2, 3 ou 4; le produit de formule R”OCF=CH2 dans laquelle R” est F(CF2)z et z est 1, 2, 3 ou 4; perfluorobutylĂ©thylĂšne; 3,3,3-trifluoropropĂšne ou 2-trifluoromĂ©thyl-3,3,3-trifluoro-l- propĂšne. According to one embodiment, the fluorinated polymer present in component C is a homopolymer of vinylidene fluoride. According to one embodiment, the fluoropolymer is a copolymer comprising vinylidene fluoride (VDF) units and units derived from one or more monomers. These other monomers are selected from the list: vinyl fluoride; trifluoroethylene; chlorotrifluoroethylene; 1,2-difluoroethylene, tetrafluoroethylene; hexafluoropropylene; perfluoro(alkyl vinyl)ethers such as perfluoro(methyl vinyl)ether, perfluoro(ethyl vinyl)ether or perfluoro(propyl vinyl)ether; perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole); the product of formula CF2=CFOCF 2 CF(CF3)OCF2CF 2 X in which X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF 2 =CF0CF2CF 2 S02F; the product of formula F(CF 2 )nCH 2 OCF=CF2 in which n is 1, 2, 3, 4 or 5; the product of formula R'CH 2 OCF=CF2 in which R' is hydrogen or F(CF 2 )z and z is 1, 2, 3 or 4; the product of formula R”OCF=CH 2 in which R” is F(CF 2 )z and z is 1, 2, 3 or 4; perfluorobutylethylene; 3,3,3-trifluoropropene or 2-trifluoromethyl-3,3,3-trifluoro-1-propene.

Parmi ces comonomĂšres du VDF, F hexafluoropropylĂšne est prĂ©fĂ©rĂ©. Les copolymĂšres de VDF peuvent Ă©galement comprendre des monomĂšres non-fluorĂ©s tel que l’éthylĂšne. Of these VDF comonomers, hexafluoropropylene is preferred. VDF copolymers can also include non-fluorinated monomers such as ethylene.

Dans les copolymĂšres de VDF, le taux massique des unitĂ©s VDF est d’au moins 50%, de prĂ©fĂ©rence au moins 60%, plus prĂ©fĂ©rablement supĂ©rieur Ă  70% et avantageusement supĂ©rieur Ă  80%. In the VDF copolymers, the mass content of the VDF units is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.

Selon un mode de rĂ©alisation, le polymĂšre fluorĂ© est fonctionnalisĂ©, en tout ou partie, ce qui lui permet d’amĂ©liorer l’adhĂ©sion sur du mĂ©tal. Dans ce cas, le polymĂšre fluorĂ© comprend des unitĂ©s monomĂšres portant au moins une fonction acide carboxylique ou anhydride d’acide carboxylique. According to one embodiment, the fluoropolymer is functionalized, in whole or in part, which allows it to improve the adhesion to metal. In this case, the fluoropolymer comprises monomer units bearing at least one carboxylic acid or carboxylic acid anhydride function.

La fonction est introduite sur le polymĂšre fluorĂ© par une rĂ©action chimique qui peut ĂȘtre du greffage ou une copolymĂ©risation du monomĂšre fluorĂ© avec un monomĂšre portant au moins un groupe -COOH ou anhydride d’acide carboxylique et une fonction vinylique capable de copolymĂ©riser avec le monomĂšre fluorĂ©, selon des techniques bien connues par l’homme du mĂ©tier. The function is introduced onto the fluorinated polymer by a chemical reaction which may be grafting or copolymerization of the fluorinated monomer with a monomer bearing at least one -COOH or carboxylic acid anhydride group and a vinyl function capable of copolymerizing with the fluorinated monomer , according to techniques well known to those skilled in the art.

Selon un mode de réalisation, on choisit comme monomÚres polaires portant une fonction carboxylique, les mono- et diacides carboxyliques insaturés ayant de 2 à 20 atomes de carbone, et en particulier de 4 à 10 atomes de carbone, tels que les acides acrylique, méthacrylique, maléique, fumarique, itaconique, citraconique, allylsuccinique, cyclohex-4-Úne-l,2-dicarboxylique, 4-méthyl-cyclohex-4-Úne-l,2-dicarboxylique, bicyclo(2,2,l)hept-5-Úne-2,3-dicarboxylique, x-méthyl bicyclo(2,2,l)hept-5-Úne-2,3- dicarboxylique et undécylénique, ainsi que leurs anhydrides. According to one embodiment, one chooses as polar monomers bearing a carboxylic function, unsaturated mono- and dicarboxylic acids having from 2 to 20 carbon atoms, and in particular from 4 to 10 carbon atoms, such as acrylic acids, methacrylic , maleic, fumaric, itaconic, citraconic, allylsuccinic, cyclohex-4-ene-1,2-dicarboxylic, 4-methyl-cyclohex-4-ene-1,2-dicarboxylic, bicyclo(2,2,l)hept-5-ene-2,3-dicarboxylic, x- methyl bicyclo(2,2,1)hept-5-ene-2,3-dicarboxylic and undecylenic, as well as their anhydrides.

Selon un mode de rĂ©alisation, les unitĂ©s portant la fonction acide carboxylique comprennent en outre un hĂ©tĂ©roatome choisi parmi l’oxygĂšne, le soufre, l’azote et le phosphore. According to one embodiment, the units carrying the carboxylic acid function also comprise a heteroatom chosen from oxygen, sulphur, nitrogen and phosphorus.

Selon un mode de rĂ©alisation, la teneur en groupes fonctionnels du polymĂšre fluorĂ© est d’au moins 0,01% molaire, de prĂ©fĂ©rence d’au moins 0,1 % molaire, et au plus de 15% molaire, de prĂ©fĂ©rence au plus 10% molaire. According to one embodiment, the functional group content of the fluorinated polymer is at least 0.01% molar, preferably at least 0.1% molar, and at most 15% molar, preferably at most 10 % molar.

Le polymĂšre fluorĂ© prĂ©sent dans le composant C peut ĂȘtre un mĂ©lange d’un ou plusieurs polymĂšres dĂ©crits ci-dessus, par exemple un mĂ©lange d’un PVDF homopolymĂšre et d’au moins un copolymĂšre de VDF, ou un mĂ©lange d’au moins deux copolymĂšres de VDF. The fluorinated polymer present in component C can be a mixture of one or more polymers described above, for example a mixture of a PVDF homopolymer and at least one VDF copolymer, or a mixture of at least two VDF copolymers.

Selon un mode de rĂ©alisation, la composition massique de plaque bipolaire mise en Ɠuvre dans le procĂ©dĂ© selon l’invention consiste en : According to one embodiment, the mass composition of the bipolar plate implemented in the method according to the invention consists of:

Graphite (composant B) : 50 Ă  85%, Graphite (component B): 50 to 85%,

- Mélange charge conductrice carbonée + polymÚre, issu du recyclage de batterie lithium-ion (composant A) : 1 à 50%, préférentiellement 10-25%, - Mixture of carbonaceous conductive filler + polymer, resulting from lithium-ion battery recycling (component A): 1 to 50%, preferably 10-25%,

Liant polymÚre (composant C) : 5 à 40%, préférentiellement 10-20%, la somme de ces pourcentages étant de 100%. Polymer binder (component C): 5 to 40%, preferably 10-20%, the sum of these percentages being 100%.

Procédés Processes

Selon un premier aspect, l’invention concerne un procĂ©dĂ© de fabrication de la composition dĂ©crite ci-dessus, ledit procĂ©dĂ© comprenant les Ă©tapes suivantes: According to a first aspect, the invention relates to a process for manufacturing the composition described above, said process comprising the following steps:

- fournir un mĂ©lange composite Ă  base d’au moins une charge conductrice carbonĂ©e et de polymĂšre(s) (composant A), - provide a composite mixture based on at least one carbonaceous conductive filler and polymer(s) (component A),

- incorporer audit mélange composite du graphite (composant B) et un liant polymÚre (composant C), caractérisé en ce que ledit mélange composite est issu du recyclage de batteries lithium- ion. - incorporating into said composite mixture graphite (component B) and a polymer binder (component C), characterized in that said composite mixture comes from the recycling of lithium-ion batteries.

Le procĂ©dĂ© selon l’invention comprend une Ă©tape de mĂ©lange Ă  l'Ă©tat fondu du composant A avec le composant C et le composant B. Cette Ă©tape permet de formuler un mĂ©lange intime. Selon un mode de rĂ©alisation, les poudres sont mĂ©langĂ©es Ă  l’état sec. The process according to the invention comprises a step of mixing in the molten state component A with component C and component B. This step makes it possible to formulate an intimate mixture. According to one embodiment, the powders are mixed in the dry state.

Selon un mode de rĂ©alisation, l’étape de mĂ©lange est rĂ©alisĂ©e Ă  l'Ă©tat fondu par extrusion, en utilisant par exemple un malaxeur ou une extrudeuse Ă  deux vis. According to one embodiment, the mixing step is carried out in the molten state by extrusion, using for example a mixer or a twin-screw extruder.

L’invention concerne Ă©galement une composition de plaque bipolaire fabriquĂ©e au moyen du procĂ©dĂ© dĂ©crit ci-dessus. The invention also relates to a bipolar plate composition manufactured using the method described above.

Plaque bipolaire Bipolar plate

L’invention concerne Ă©galement une plaque bipolaire comprenant la composition dĂ©crite ci-dessus, sous une forme agglomĂ©rĂ©e. Une plaque bipolaire est une plaque sui sĂ©pare les cellules Ă©lĂ©mentaires dans les piles Ă  combustible, les Ă©lectrolyseurs et les batteries Ă  flux redox. En gĂ©nĂ©ral, elle a une forme de parallĂ©lĂ©pipĂšde ayant une Ă©paisseur de quelques millimĂštres (typiquement comprise entre 0,2 et 6 mm) et comprend sur chaque face un rĂ©seau de canaux pour la circulation des gaz et des fluides. Ses fonctions consistent Ă  alimenter la pile Ă  combustible avec du carburant gazeux, Ă  Ă©vacuer les produits de rĂ©action et Ă  collecter le courent Ă©lectrique produit par la cellule. The invention also relates to a bipolar plate comprising the composition described above, in an agglomerated form. A bipolar plate is a plate that separates elementary cells in fuel cells, electrolyzers and redox flow batteries. In general, it has the shape of a parallelepiped having a thickness of a few millimeters (typically between 0.2 and 6 mm) and comprises on each face a network of channels for the circulation of gases and fluids. Its functions are to supply the fuel cell with gaseous fuel, to evacuate the reaction products and to collect the electric current produced by the cell.

L’invention concerne, selon un autre aspect, un procĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: The invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:

- préparer une composition selon le procédé décrit ci-dessus, et - preparing a composition according to the process described above, and

- soumettre ladite composition Ă  un moulage par injection. - Subjecting said composition to injection molding.

De préférence, la composition pour plaque bipolaire est soumise à un moulage par injection sous forme de poudre. Preferably, the bipolar plate composition is subjected to injection molding in powder form.

Le procĂ©dĂ© selon l’invention peut comprendre en outre une Ă©tape supplĂ©mentaire de broyage de cette poudre, par exemple au moyen d’un broyeur Ă  disques. The method according to the invention may also comprise an additional step of grinding this powder, for example by means of a disc mill.

Les compositions de l’invention sont particuliĂšrement bien adaptĂ©es Ă  la fabrication de plaques bipolaires composites par le procĂ©dĂ© de moulage par injection. Le procĂ©dĂ© de moulage par injection consiste en plusieurs Ă©tapes. Tout d’abord, des granulĂ©s ou poudres sont introduits dans une extrudeuse via une trĂ©mie d’alimentation. Une fois introduite, la matiĂšre est acheminĂ©e dans le fourreau oĂč elle est simultanĂ©ment chauffĂ©e, cisaillĂ©e et convoyĂ©e vers le moule par la vis d’extrusion. La matiĂšre est maintenue momentanĂ©ment dans le fourreau et mise sous pression avant la phase d’injection. Lorsque la pression adĂ©quate est atteinte, la matiĂšre est injectĂ©e dans un moule ayant la forme et les dimensions de l’objet final souhaitĂ©, la tempĂ©rature du moule Ă©tant rĂ©gulĂ©e. La durĂ©e du cycle dĂ©pend de la taille des piĂšces et du temps de solidification du polymĂšre. Le maintien sous pression de la matiĂšre une fois injectĂ©e dans le moule limite la dĂ©formation et le retrait aprĂšs dĂ©moulage. Pour Ă©jecter les piĂšces, les parties du moule se sĂ©parent, le noyau se rĂ©tracte et les Ă©jecteurs sont poussĂ©s pour dĂ©coller les piĂšces de la surface du moule. The compositions of the invention are particularly well suited to the manufacture of composite bipolar plates by the injection molding process. The injection molding process consists of several steps. First, granules or powders are introduced into an extruder via a feed hopper. Once introduced, the material is routed into the barrel where it is simultaneously heated, sheared and conveyed to the mold by the extrusion screw. The material is temporarily held in the sheath and put under pressure before the injection phase. When the appropriate pressure is reached, the material is injected into a mold having the shape and dimensions of the desired final object, the temperature of the mold being regulated. The cycle time depends on the size of the parts and the solidification time of the polymer. the keeping the material under pressure once injected into the mold limits deformation and shrinkage after demoulding. To eject the parts, the mold parts separate, the core retracts, and the ejectors are pushed to lift the parts off the mold surface.

Les paramĂštres du procĂ©dĂ© d’injection sont multiples : tempĂ©rature de la matiĂšre lors de l’étape de plastification, vitesse d’injection, pression d’injection de la matiĂšre, temps et pression de maintien dans le moule, tempĂ©rature du moule. The parameters of the injection process are multiple: temperature of the material during the plasticizing step, injection speed, injection pressure of the material, time and pressure held in the mould, mold temperature.

Dans le cas de l’injection de plaques bipolaires composites de l’invention, le profil de tempĂ©rature appliquĂ© le long de la vis d’extrusion peut varier de 100°C Ă  280°C depuis la zone d’alimentation jusqu’à la tĂȘte d’injection. La tempĂ©rature du moule peut varier de la tempĂ©rature ambiante jusqu’à 280°C. Plusieurs procĂ©dĂ©s de refroidissement du moule peuvent ĂȘtre utilisĂ©s. La matiĂšre peut ĂȘtre injectĂ©e dans un moule maintenu Ă  une tempĂ©rature comprise entre les tempĂ©ratures de fusion et de transition vitreuse pour un polymĂšre semi-cristallin. In the case of the injection of composite bipolar plates of the invention, the temperature profile applied along the extrusion screw can vary from 100° C. to 280° C. from the feed zone to the head. injection. The mold temperature can vary from room temperature up to 280°C. Several mold cooling methods can be used. The material can be injected into a mold maintained at a temperature between the melting and glass transition temperatures for a semi-crystalline polymer.

Par ailleurs, il existe des procĂ©dĂ©s d’injection pour lesquels la tempĂ©rature du moule varie au cours du cycle d’injection. Dans ce type de procĂ©dĂ©, la matiĂšre est tout d’abord injectĂ©e dans un moule dont la tempĂ©rature est supĂ©rieure Ă  la tempĂ©rature de fusion pour un polymĂšre thermoplastique semi-cristallin. Cette phase favorise le remplissage du moule. Ensuite, le moule est refroidi jusqu’à une tempĂ©rature comprise entre les tempĂ©ratures de fusion et de transition vitreuse pour un polymĂšre semi-cristallin afin de favoriser la cristallisation Des versions commerciales de ces procĂ©dĂ©s Ă  tempĂ©rature de moule variable existent. On peut citer par exemple les technologies Roctool, Variotherm et Variomelt. In addition, there are injection processes for which the temperature of the mold varies during the injection cycle. In this type of process, the material is first injected into a mold whose temperature is higher than the melting temperature for a semi-crystalline thermoplastic polymer. This phase favors the filling of the mould. Next, the mold is cooled to a temperature between the melting and glass transition temperatures for a semi-crystalline polymer to promote crystallization. Commercial versions of these variable mold temperature processes exist. Examples include Roctool, Variotherm and Variomelt technologies.

Les autres paramĂštres d’injection tels que vitesse d’injection, pression d’injection de la matiĂšre, temps et pression de maintien dans le moule dĂ©pendent de la gĂ©omĂ©trie du moule, de ses dimensions, de la taille et position des seuils d’injection. The other injection parameters such as injection speed, injection pressure of the material, time and holding pressure in the mold depend on the geometry of the mold, its dimensions, the size and position of the injection gates .

L’invention concerne, selon un autre aspect, un procĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: The invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:

- préparer une composition selon le procédé décrit ci-dessus, et - preparing a composition according to the method described above, and

- soumettre ladite composition Ă  un moulage par compression. - Subjecting said composition to compression molding.

De prĂ©fĂ©rence, la composition pour plaque bipolaire est soumise Ă  un moulage par compression sous forme de poudre. Le procĂ©dĂ© selon l’invention peut comprendre en outre une Ă©tape de broyage de cette poudre, par exemple au moyen d’un broyeur Ă  disques. Preferably, the bipolar plate composition is subjected to compression molding in powder form. The method according to the invention may also comprise a step of grinding this powder, for example by means of a disk mill.

Le moulage par compression de compositions destinĂ©es Ă  produire des plaques bipolaires peut ĂȘtre rĂ©alisĂ© en introduisant ladite composition dans un moule, par exemple un moule en acier inoxydable, qui est ensuite fermĂ© et chauffĂ© Ă  une tempĂ©rature allant de 200°C Ă  350°C, de prĂ©fĂ©rence de 250°C Ă  300°C. Ensuite, une force de compression de 300 t Ă  800 t, de prĂ©fĂ©rence de 400 t Ă  600 t, est appliquĂ©e au moule, pour un moule de dimensions de 100000 Ă  150000 mm2. Typiquement, une force de compression de 500 t est appliquĂ©e lorsque la taille du moule est de 130000 mm2 et une force de compression de 300 t est appliquĂ©e lorsque la taille du moule est de 44000 mm2. Le moule est ensuite refroidi Ă  une tempĂ©rature de 50°C Ă  120°C, de prĂ©fĂ©rence de 60°C Ă  100°C, et la plaque est dĂ©moulĂ©e. The compression molding of compositions intended to produce bipolar plates can be carried out by introducing said composition into a mould, for example a stainless steel mould, which is then closed and heated to a temperature ranging from 200°C to 350°C, preferably from 250°C to 300°C. Then, a compression force of 300 t to 800 t, preferably 400 t to 600 t, is applied to the mold, for a mold with dimensions of 100,000 to 150,000 mm 2 . Typically, a compression force of 500 t is applied when the mold size is 130000 mm 2 and a compression force of 300 t is applied when the mold size is 44000 mm 2 . The mold is then cooled to a temperature of 50° C. to 120° C., preferably 60° C. to 100° C., and the plate is unmolded.

L’invention concerne, selon un autre aspect, un procĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: The invention relates, according to another aspect, to a method of manufacturing a bipolar plate, comprising the following steps:

- préparer une composition selon le procédé décrit ci-dessus, et - preparing a composition according to the process described above, and

- soumettre ladite composition Ă  un procĂ©dĂ© d’extrusion en continu. - subjecting said composition to a continuous extrusion process.

La composition est introduite dans une extrudeuse de type monovis ou bivis avec une filiÚre plate, de façon à obtenir une plaque en continu qui est par la suite gravée. The composition is introduced into a single-screw or twin-screw type extruder with a flat die, so as to obtain a continuous plate which is subsequently etched.

L’invention concerne en outre les plaques bipolaires obtenues par les procĂ©dĂ©s dĂ©crits ci-dessus. The invention further relates to the bipolar plates obtained by the methods described above.

Avantageusement, la plaque bipolaire présente au moins une des caractéristiques suivantes, et de préférence toutes ces caractéristiques : Advantageously, the bipolar plate has at least one of the following characteristics, and preferably all of these characteristics:

- une résistivité surfacique égale ou inférieure à 0,01 Ohm.cm ; - a surface resistivity equal to or less than 0.01 Ohm.cm;

- une résistivité volumique égale ou inférieure à 0,03 Ohm.cm; - a volume resistivity equal to or less than 0.03 Ohm.cm;

- une conductivité thermique égale ou supérieure à 10 W/m/K; une résistance à la flexion égale ou supérieure à 25 N/mm2; - a thermal conductivity equal to or greater than 10 W/m/K; a flexural strength equal to or greater than 25 N/mm 2 ;

- une résistance à la compression égale ou supérieure à 25 N/mm2. - a compressive strength equal to or greater than 25 N/mm 2 .

La rĂ©sistance Ă  la flexion est mesurĂ©e selon la norme DIN EN ISO 178. La rĂ©sistance Ă  la compression est mesurĂ©e selon la norme ISO 604. La conductivitĂ© thermique est mesurĂ©e selon la technique Laser Llash selon la norme DIN EN ISO 821. La rĂ©sistivitĂ© surfacique est mesurĂ©e au moyen d’échantillons de sonde Ă  quatre points sur des Ă©chantillons broyĂ©s ayant une Ă©paisseur de 4 mm. La rĂ©sistivitĂ© volumique est mesurĂ©e avec une installation Ă  deux Ă©lectrodes et une pression de contact de 1 N/mm2 sur des Ă©chantillons surfacĂ©s ayant un diamĂštre de 13 mm et une Ă©paisseur de 2 mm. Bending strength is measured according to DIN EN ISO 178. Compressive strength is measured according to ISO 604. Thermal conductivity is measured using the Laser Llash technique according to DIN EN ISO 821. Surface resistivity is measured by means of probe samples at four points on crushed samples having a thickness of 4 mm. Volume resistivity is measured with a two-electrode installation and a contact pressure of 1 N/mm 2 on surfaced samples having a diameter of 13 mm and a thickness of 2 mm.

Selon certains modes de réalisation, la plaque bipolaire présente une résistivité surfacique égale ou inférieure à 0,008 Ohm.cm, ou égale ou inférieure à 0,005 Ohm.cm, ou égale ou inférieure à 0,003 Ohm.cm, ou égale ou inférieure à 0.001 Ohm.cm. According to certain embodiments, the bipolar plate has a surface resistivity equal to or less than 0.008 Ohm.cm, or equal to or less than 0.005 Ohm.cm, or equal to or less than 0.003 Ohm.cm, or equal to or less than 0.001 Ohm. cm.

Selon certains modes de réalisation, la plaque bipolaire présente une résistivité traversante égale ou inférieure à 0,025 Ohm.cm, ou égale ou inférieure à 0,02 Ohm.cm, ou égale ou inférieure à 0,015 Ohm.cm. According to certain embodiments, the bipolar plate has a through resistivity equal to or less than 0.025 Ohm.cm, or equal to or less than 0.02 Ohm.cm, or equal to or less than 0.015 Ohm.cm.

Selon certains modes de réalisation, la plaque bipolaire possÚde une conductivité thermique égale ou supérieure à 15 W/m/K, ou égale ou supérieure à 20 W/m/K. According to certain embodiments, the bipolar plate has a thermal conductivity equal to or greater than 15 W/m/K, or equal to or greater than 20 W/m/K.

Selon certains modes de réalisation, la plaque bipolaire présente une résistance à la flexion égale ou supérieure à 30 N/mm2, ou égale ou supérieure à 35 N/mm2. According to certain embodiments, the bipolar plate has a resistance to bending equal to or greater than 30 N/mm 2 , or equal to or greater than 35 N/mm 2 .

Selon un mode de réalisation préféré, la plaque bipolaire consiste en : According to a preferred embodiment, the bipolar plate consists of:

- de 50 à 85% de composant B tel que défini dans la présente invention ayant un diamÚtre moyen en volume (Dv50) allant de 50 à 500 mhi, - from 50 to 85% of component B as defined in the present invention having an average volume diameter (Dv50) ranging from 50 to 500 mhi,

- de 1 à 50% de composant A tel que défini dans la présente invention et comprenant du graphite ayant une taille de particules, exprimée en diamÚtre moyen en volume (Dv50) allant de 1 à 40 mhi, de 5 à 40 % de composant C tel que défini dans la présente invention ; la somme de ces pourcentages étant de 100%. - from 1 to 50% of component A as defined in the present invention and comprising graphite having a particle size, expressed as volume average diameter (Dv50) ranging from 1 to 40 mhi, from 5 to 40% of component C as defined in the present invention; the sum of these percentages being 100%.

Exemples Examples

Pour la prĂ©paration des plaques bipolaires, un graphite synthĂ©tique (Graphite Timrex KS150) ayant une taille de particule caractĂ©risĂ©e par un Dv50 de 55mhi et un homopolymĂšre de difluorure de vinylidĂšne qui possĂšde une viscositĂ© Ă  l’état fondu mesurĂ©e Ă  232°C et 100 s- 1 de 900 Pa.s ont Ă©tĂ© utilisĂ©s. For the preparation of the bipolar plates, a synthetic graphite (Graphite Timrex KS150) having a particle size characterized by a Dv50 of 55mhi and a homopolymer of vinylidene difluoride which has a melt viscosity measured at 232°C and 100 s - 1 of 900 Pa.s were used.

Composition 1 issue du recyclage d’une anode graphite de batterie Lithium-ion:Composition 1 from the recycling of a lithium-ion battery graphite anode:

La composition 1 issue d’une anode en graphite a Ă©tĂ© obtenue par un procĂ©dĂ© de recyclage basĂ© sur la sĂ©paration physique des Ă©lĂ©ments. Tout d’abord, les Ă©lĂ©ments constitutifs de la batterie (anode/sĂ©parateur/cathode) ont Ă©tĂ© sĂ©parĂ©s physiquement. L’anode a Ă©tĂ© ensuite broyĂ©e. Enfin, elle a Ă©tĂ© soumise Ă  un tamisage Ă  jet d’air pour sĂ©parer les fragments de cuivre, du graphite et des liants polymĂšres. A l’issue de cette Ă©tape, on a rĂ©cupĂ©rĂ© une poudre constituĂ©e de 96.3% en poids de graphite, 3.4% en poids de carboxymethyl cellulose (CMC) et de 2.6% en poids d’un Ă©lastomĂšre de styrĂšne et de butadiĂšne (SBR). Le graphite dans cette composition Ă©tait un graphite synthĂ©tique qui possĂšde une taille de particule caractĂ©risĂ©e par un Dv50 de 17 mhi. Composition 1 from a graphite anode was obtained by a recycling process based on the physical separation of the elements. First, the battery components (anode/separator/cathode) were physically separated. The anode was then crushed. Finally, it was subjected to an air jet sieving to separate the copper fragments, graphite and polymeric binders. At the end of this step, a powder consisting of 96.3% by weight of graphite, 3.4% by weight of carboxymethyl cellulose (CMC) and 2.6% by weight of a styrene and butadiene elastomer (SBR) was recovered. . The graphite in this composition was a synthetic graphite which has a particle size characterized by a Dv50 of 17 mhi.

Composition 2 issue de la black mass d’une batterie Lithium-ion avec anode graphite et cathode NMC: La composition 2 est issue de la black mass d’une batterie Lithium-ion. Elle contient les rĂ©sidus non mĂ©talliques et non-inorganiques, c’est-Ă -dire le graphite, la charge carbonĂ©e conductrice de la cathode, les liants polymĂšres des Ă©lectrodes (PVDL, CMC, SBR) et la polyolĂ©fine du sĂ©parateur. Les Ă©lĂ©ments constitutifs de la batterie (anode/sĂ©parateur/cathode) ont Ă©tĂ© tout d’abord dĂ©chiquetĂ©s puis broyĂ©s. Ensuite, le broyĂąt a Ă©tĂ© soumis aux diffĂ©rentes Ă©tapes d’un procĂ©dĂ© d’hydromĂ©tallurgie afin de dissoudre les collecteurs de courant mĂ©talliques et les charges inorganiques telles que la NMC et la bohĂ©mite du revĂȘtement du sĂ©parateur. Les rĂ©sidus du procĂ©dĂ© d’hydromĂ©tallurgie sont composĂ©s de : Composition 2 from the black mass of a Lithium-ion battery with graphite anode and NMC cathode: Composition 2 is from the black mass of a Lithium-ion battery. It contains the non-metallic and non-inorganic residues, i.e. the graphite, the conductive carbonaceous filler of the cathode, the polymer binders of the electrodes (PVDL, CMC, SBR) and the polyolefin of the separator. The constituent elements of the battery (anode/separator/cathode) were first shredded and then ground. Then, the ground material was subjected to the different stages of a hydrometallurgy process in order to dissolve the metallic current collectors and the inorganic fillers such as NMC and bohemite from the separator coating. The residues from the hydrometallurgy process are composed of:

- 82.7% en poids de graphite issu de l’anode. Il possĂšde une taille de particule caractĂ©risĂ©e par un Dv50 de 17 mhi. - 82.7% by weight of graphite from the anode. It has a particle size characterized by a Dv50 of 17 mhi.

- 1.8% en poids de carboxymethyl cellulose (CMC) - 1.8% by weight of carboxymethyl cellulose (CMC)

- 1.4% en poids d’un Ă©lastomĂšre de styrĂšne et de butadiĂšne (SBR) - 1.4% by weight of a styrene and butadiene elastomer (SBR)

- 4.1% en poids de polyfluorure de vinylidĂšne (PVDL) issu de la cathode - 4.1% by weight of polyvinylidene fluoride (PVDL) from the cathode

- 4.1% en poids de noir de carbone issu de la cathode - 5.9% en poids de polyoléfine issu du séparateur - 4.1% by weight of carbon black from the cathode - 5.9% by weight of polyolefin from the separator

Composition des plaques bipolaires Ă  iso taux de liant: Composition of the bipolar plates with iso rate of binder:

Tableau 1 : Composition des plaques bipolaires produites Table 1: Composition of the bipolar plates produced

Préparation des plaques bipolaires : Preparation of bipolar plates:

‱ PrĂ©-mĂ©lange de la composition servant Ă  la fabrication de la plaque bipolaire :‱ Premix of the composition used to manufacture the bipolar plate:

Les constituants de l’exemple 1, le graphite Timrex KS150, le PVDF KynarÂź 721 et la composition issue du recyclage d’une anode de batterie lithium-ion, ont Ă©tĂ© prĂ©-mĂ©langĂ©s Ă  l’aide d’une extrudeuse bi-vis. A l’issue de cette Ă©tape de mĂ©lange des granulĂ©s trĂšs friables ont Ă©tĂ© obtenus. Ces granulĂ©s ont Ă©tĂ© ensuite broyĂ©s Ă  l’aide d’un broyeur Ă  disques de façon Ă  obtenir une poudre d’une taille moyenne Dv50 infĂ©rieure Ă  500 mhi. The constituents of Example 1, the Timrex KS150 graphite, the KynarÂź 721 PVDF and the composition resulting from the recycling of a lithium-ion battery anode, were pre-mixed using a twin-screw extruder . At the end of this mixing step, very friable granules were obtained. These granules were then ground using a disc mill to obtain a powder with an average size Dv50 of less than 500 mhi.

La composition de l’exemple comparatif a Ă©tĂ© prĂ©parĂ©e selon le mĂȘme protocole. The composition of the comparative example was prepared according to the same protocol.

‱ Fabrication de la plaque bipolaire par thermocompression : ‱ Manufacture of the bipolar plate by thermocompression:

La fabrication des plaques bipolaires a Ă©tĂ© effectuĂ©e par thermocompression. Pour ce faire, un moule d’une dimension de 30x30 cm2 a Ă©tĂ© rempli manuellement avec la composition sous forme de poudre. Le poudre a Ă©tĂ© nivelĂ©e manuellement avec une lame mĂ©tallique. Le moule a Ă©tĂ© fermĂ© et portĂ© Ă  240° C sous une pression de 150 bars. La quantitĂ© de poudre a Ă©tĂ© ajustĂ©e pour obtenir une Ă©paisseur d’environ 3mm. Le moule a Ă©tĂ© refroidi sous pression jusqu’à une tempĂ©rature de 80°C. Une fois atteinte cette tempĂ©rature, la pression a Ă©tĂ© supprimĂ©e et la plaque a Ă©tĂ© retirĂ©e du moule. The fabrication of the bipolar plates was carried out by thermocompression. To do this, a mold with a dimension of 30×30 cm 2 was manually filled with the composition in powder form. The powder was leveled manually with a metal blade. The mold was closed and brought to 240° C. under a pressure of 150 bars. The amount of powder was adjusted to obtain a thickness of approximately 3mm. The mold was cooled under pressure to a temperature of 80°C. Once this temperature was reached, the pressure was released and the plate was removed from the mould.

Méthode de caractérisation : Characterization method:

‱ RĂ©sistance Ă  la flexion ‱ Resistance to bending

La résistance à la flexion a été mesurée selon la norme DIN EN ISO 178. Résultats : The flexural strength was measured according to DIN EN ISO 178. Results :

Comme le dĂ©montre les rĂ©sultats, les plaques bipolaires selon la prĂ©sente invention prĂ©sentent une meilleure rĂ©sistance Ă  la flexion par rapport Ă  l’exemple comparatif dans lequel il n’y a pas de graphite issu du recyclage d’une batterie. As demonstrated by the results, the bipolar plates according to the present invention have a better resistance to bending compared to the comparative example in which there is no graphite resulting from the recycling of a battery.

Claims

REVENDICATIONS 1. ProcĂ©dĂ© de fabrication d’une composition pour plaque bipolaire, ledit procĂ©dĂ© comprenant les Ă©tapes suivantes: 1. A method of manufacturing a composition for a bipolar plate, said method comprising the following steps: - fournir un mĂ©lange composite Ă  base d’au moins une charge conductrice carbonĂ©e et de polymĂšre(s) (composant A), - provide a composite mixture based on at least one carbonaceous conductive filler and polymer(s) (component A), - incorporer audit mĂ©lange composite du graphite (composant B) et un liant polymĂšre (composant C), caractĂ©risĂ© en ce que ledit mĂ©lange composite est issu du recyclage de batteries lithium-ion. - incorporating into said composite mixture graphite (component B) and a polymer binder (component C), characterized in that said composite mixture comes from the recycling of lithium-ion batteries. 2. ProcĂ©dĂ© selon la revendication 1, dans lequel le recyclage de batteries lithium-ion est effectuĂ© par un procĂ©dĂ© choisi parmi la sĂ©paration physique, G hydromĂ©tallurgie, ou une combinaison de ceux-ci. 2. Process according to claim 1, in which the recycling of lithium-ion batteries is carried out by a process selected from physical separation, hydrometallurgy, or a combination thereof. 3. ProcĂ©dĂ© selon l’une des revendications 1 et 2, dans lequel ladite au moins une charge conductrice carbonĂ©e est du graphite utilisĂ© comme charge active Ă  l’anode de batterie lithium-ion. 3. Method according to one of claims 1 and 2, wherein said at least one carbonaceous conductive filler is graphite used as active filler at the lithium-ion battery anode. 4. ProcĂ©dĂ© selon l’une des revendications 1 Ă  3, dans lequel ladite charge conductrice carbonĂ©e est un mĂ©lange de graphite et d'une autre charge conductrice carbonĂ©e, comme le noir de carbone, les nanotubes de carbone ou les fibres de carbone, prĂ©sents dans la formulation de l'anode ou de la cathode de batterie Li-ion. 4. Method according to one of claims 1 to 3, wherein said carbonaceous conductive filler is a mixture of graphite and another carbonaceous conductive filler, such as carbon black, carbon nanotubes or carbon fibers, present in the formulation of Li-ion battery anode or cathode. 5. ProcĂ©dĂ© selon l’une des revendications 1 Ă  4, dans lequel ledit polymĂšre entrant dans la composition du composant A est un polymĂšre fluorĂ©, un polymĂšre Ă©paississant hydrosoluble, un Ă©lastomĂšre polyolĂ©fine, une rĂ©sine acrylique ou un mĂ©lange de plusieurs de ces composants, y compris un mĂ©lange de polymĂšres fluorĂ©s diffĂ©rents. 5. Method according to one of claims 1 to 4, wherein said polymer forming part of the composition of component A is a fluorinated polymer, a water-soluble thickening polymer, a polyolefin elastomer, an acrylic resin or a mixture of several of these components, including a mixture of different fluorinated polymers. 6. ProcĂ©dĂ© selon la revendication 5, dans lequel ledit polymĂšre fluorĂ© est choisi parmi : les homopolymĂšres de fluorure de vinylidĂšne ; les copolymĂšres comprenant des unitĂ©s de fluorure de vinylidĂšne et des unitĂ©s issues d’un ou plusieurs monomĂšres choisis dans la liste : fluorure de vinyle; trifluoroĂ©thylĂšne; chlorotrifluoroĂ©thylĂšne; 1 ,2-difluoroĂ©thylĂšne, tĂ©trafluoroĂ©thylĂšne; hexafluoropropylĂšne; perfluoro(alkyl vinyl)Ă©thers tels que le perfluoro(mĂ©thyl vinyl)Ă©ther, perfluoro(Ă©thyl vinyl)Ă©ther ou perfluoro(propyl vinyl)Ă©ther; perfluoro(l,3-dioxole); perfluoro(2,2- dimĂ©thyl-l,3-dioxole); le produit de formule6. Process according to claim 5, in which said fluorinated polymer is chosen from: homopolymers of vinylidene fluoride; copolymers comprising vinylidene fluoride units and units resulting from one or more monomers chosen from the list: vinyl fluoride; trifluoroethylene; chlorotrifluoroethylene; 1,2-difluoroethylene, tetrafluoroethylene; hexafluoropropylene; perfluoro(alkyl vinyl)ethers such as perfluoro(methyl vinyl)ether, perfluoro(ethyl vinyl)ether or perfluoro(propyl vinyl)ether; perfluoro(1,3-dioxole); perfluoro(2,2-dimethyl-1,3-dioxole); the formula product CF2=CFOCF2CF(CF3)OCF2CF2X dans laquelle X est SO2F, CO2H, CH2OH, CH2OCN ou CH2OPO3H; le produit de formule CF2=CF0CF2CF2S02F; le produit de formule F(CF2)nCH2OCF=CF2 dans laquelle n est 1, 2, 3, 4 ou 5; le produit de formule R’CH2OCF=CF2 dans laquelle R’ est hydrogĂšne ou F(CF2)z et z est 1, 2, 3 ou 4; le produit de formule R”OCF=CH2 dans laquelle R” est F(CF2)z et z est 1, 2, 3 ou 4; perfluorobutylĂ©thylĂšne; 3,3,3-trifluoropropĂšne ou 2-trifluoromĂ©thyl-3,3,3- trifluoro-l-propĂšne ; l’acide acrylique, l’acide mĂ©thacrylique, l’hydroxyĂ©thyl(mĂ©th)acrylate, l’hydroxypropyl(mĂ©th)acrylate, l’hydroxyĂ©thylhexyl(mĂ©th)acrylate, l’acryloyloxy propyl succinate ; et leurs mĂ©langes. CF2=CFOCF 2 CF(CF 3 )OCF2CF 2 X wherein X is SO2F, CO2H, CH2OH, CH2OCN or CH2OPO3H; the product of formula CF2=CF0CF 2 CF 2 S02F; the product of formula F(CF 2 )nCH 2 OCF=CF 2 in which n is 1, 2, 3, 4 or 5; the product of formula R'CH 2 OCF=CF2 in which R' is hydrogen or F(CF 2 )z and z is 1, 2, 3 or 4; the product of formula R”OCF=CH 2 in which R” is F(CF 2 )z and z is 1, 2, 3 or 4; perfluorobutylethylene; 3,3,3-trifluoropropene or 2-trifluoromethyl-3,3,3-trifluoro-1-propene; acrylic acid, methacrylic acid, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxyethylhexyl(meth)acrylate, acryloyloxy propyl succinate; and their mixtures. 7. ProcĂ©dĂ© selon l’une des revendications 1 Ă  6, dans lequel composant A prĂ©sente la composition massique suivante : 7. Method according to one of claims 1 to 6, in which component A has the following mass composition: - 60 Ă  100% de graphite, - 60 to 100% graphite, - 0 Ă  20% de silicium, - 0 to 20% silicon, - 0 Ă  10% d’épaississant hydrosoluble, - 0 to 10% water-soluble thickener, - 0 Ă  10% d’élastomĂšre polyolĂ©fine, - 0 to 10% polyolefin elastomer, - 0 Ă  10% de rĂ©sine acrylique, - 0 to 10% acrylic resin, - 0 Ă  10% de polymĂšre(s) fluorĂ©(s), - 0 to 10% fluorinated polymer(s), - 0 Ă  40% de polyolĂ©fine, - 0 to 40% polyolefin, - 0 Ă  10% d'une seconde charge conductrice carbonĂ©e, la somme de tous ces pourcentages Ă©tant de 100%. - 0 to 10% of a second carbonaceous conductive filler, the sum of all these percentages being 100%. 8. ProcĂ©dĂ© selon l’une des revendications prĂ©cĂ©dentes caractĂ©risĂ© en ce que le composant A comprenant du graphite ayant une taille de particules, exprimĂ©e en diamĂštre moyen en volume (Dv50), infĂ©rieure au diamĂštre moyen en volume (Dv50) du graphite constituant le composant B. 8. Method according to one of the preceding claims, characterized in that component A comprising graphite having a particle size, expressed as volume average diameter (Dv50), less than the volume average diameter (Dv50) of the graphite constituting the component B. 9. ProcĂ©dĂ© selon l’une des revendications 1 Ă  8, dans lequel le graphite prĂ©sent dans le composant A prĂ©sente une taille de particules, exprimĂ©e en diamĂštre moyen en volume (Dv50) allant de 1 Ă  40 mhi, prĂ©fĂ©rentiellement de 5 Ă  30qm. 9. Method according to one of claims 1 to 8, in which the graphite present in component A has a particle size, expressed as volume average diameter (Dv50) ranging from 1 to 40 mhi, preferably from 5 to 30 ÎŒm. 10. ProcĂ©dĂ© selon l’une des revendications 1 Ă  9, dans lequel le graphite constituant le composant B a un diamĂštre moyen en volume (Dv50) allant de 50 Ă  500 pm, prĂ©fĂ©rentiellement 75 Ă  150 mhi. 10. Method according to one of claims 1 to 9, in which the graphite constituting component B has a volume-average diameter (Dv50) ranging from 50 to 500 ÎŒm, preferably 75 to 150 ÎŒm. 11. ProcĂ©dĂ© selon l’une des revendications 1 Ă  10, dans lequel ledit liant polymĂšre constituant le composant C est une polyolĂ©fĂŻne, un polymĂšre fluorĂ©, le polyphĂ©nylsulfone, le polyĂ©thersulfone, une rĂ©sine phĂ©nolique, une rĂ©sine vinylester, une rĂ©sine Ă©poxyde, ou un polymĂšre cristal-liquide. 11. Method according to one of claims 1 to 10, wherein said polymer binder constituting component C is a polyolefin, a fluorinated polymer, polyphenylsulfone, polyethersulfone, a phenolic resin, a vinylester resin, an epoxy resin, or a liquid crystal polymer. 12. ProcĂ©dĂ© selon l’une des revendications 1 Ă  11, dans lequel la composition massique de plaque bipolaire mise en Ɠuvre dans le procĂ©dĂ© consiste en : composant B : 50 Ă  85%, composant A : 1 Ă  50%, prĂ©fĂ©rentiellement 10-25% composant C : 5 Ă  40%, prĂ©fĂ©rentiellement 10-20% la somme de ces pourcentages Ă©tant de 100%. 12. Method according to one of claims 1 to 11, in which the mass composition of the bipolar plate used in the method consists of: component B: 50 to 85%, component A: 1 to 50%, preferably 10-25 % of component C: 5 to 40%, preferably 10-20%, the sum of these percentages being 100%. 13. ProcĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: 13. Process for manufacturing a bipolar plate, comprising the following steps: - prĂ©parer une composition selon le procĂ©dĂ© selon l’une des revendications 1 Ă  12, et - preparing a composition according to the process according to one of claims 1 to 12, and - soumettre ladite composition Ă  un moulage par injection. - Subjecting said composition to injection molding. 14. ProcĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: 14. Process for manufacturing a bipolar plate, comprising the following steps: - prĂ©parer une composition selon le procĂ©dĂ© selon l’une des revendications 1 Ă  12, et - preparing a composition according to the process according to one of claims 1 to 12, and - soumettre la composition Ă  un moulage par compression. - Subjecting the composition to compression molding. 15. ProcĂ©dĂ© de fabrication d’une plaque bipolaire, comprenant les Ă©tapes suivantes: 15. Process for manufacturing a bipolar plate, comprising the following steps: - prĂ©parer une composition selon le procĂ©dĂ© selon l’une des revendications 1 Ă  12, et - preparing a composition according to the process according to one of claims 1 to 12, and - soumettre la composition Ă  un procĂ©dĂ© d’extrusion en continu. - subjecting the composition to a continuous extrusion process. 16. Plaque bipolaire obtenue par le procĂ©dĂ© selon la revendication 13. 16. Bipolar plate obtained by the process according to claim 13. 17. Plaque bipolaire obtenue par le procĂ©dĂ© selon la revendication 14. 17. Bipolar plate obtained by the process according to claim 14. 18. Plaque bipolaire obtenue par le procĂ©dĂ© selon la revendication 15. 18. Bipolar plate obtained by the process according to claim 15. 19. Plaque bipolaire consistant en 19. Bipolar plate consisting of - de 50 Ă  85% de composant B tel que dĂ©fini selon l’une quelconque des revendications 1 Ă  12 ayant un diamĂštre moyen en volume (Dv50) allant de 50 Ă  500 pm, de 1 Ă  50% de composant A tel que dĂ©fini selon l’une quelconque des revendications 1 Ă  12 et comprenant du graphite ayant une taille de particules, exprimĂ©e en diamĂštre moyen en volume (Dv50) allant de 1 Ă  40 pm, de 5 Ă  40 % de composant C tel que dĂ©fini selon l’une quelconque des revendications 1 Ă  12 ; la somme de ces pourcentages Ă©tant de 100%. - from 50 to 85% of component B as defined according to any one of claims 1 to 12 having an average diameter by volume (Dv50) ranging from 50 to 500 ÎŒm, from 1 to 50% of component A as defined according to any one of claims 1 to 12 and comprising graphite having a particle size, expressed as volume average diameter (Dv50) ranging from 1 to 40 ”m, from 5 to 40% of component C as defined according to one any of claims 1 to 12; the sum of these percentages being 100%.
EP22754902.9A 2021-07-21 2022-07-13 Method for manufacturing bipolar plates Pending EP4374437A1 (en)

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