Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
  • H01M4/623—Binders being polymers fluorinated polymers
• • 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
  • H01M10/04—Construction or manufacture in general
  • H01M10/0413—Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
• • 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
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • 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
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
• • 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
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
  • H01M10/0568—Liquid materials characterised by the solutes
• • 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
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
  • H01M10/0569—Liquid materials characterised by the solvents
• • 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
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/058—Construction or manufacture
  • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• • 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
  • H01M10/04—Construction or manufacture in general
  • H01M10/0413—Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
  • H01M10/0418—Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes with bipolar electrodes
• • 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
  • H01M10/04—Construction or manufacture in general
  • H01M10/0436—Small-sized flat cells or batteries for portable equipment
  • H01M10/044—Small-sized flat cells or batteries for portable equipment with 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
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/023—Gel electrode
• • 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
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
  • H01M2004/029—Bipolar electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0085—Immobilising or gelification of electrolyte
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0088—Composites
  • H01M2300/0091—Composites in the form of mixtures
• • 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
  • Y02E60/10—Energy storage using batteries
• • 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
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

• the invention relates to the field of electrochemical accumulators with bipolar architecture comprising a specific structure not requiring in particular the installation of seals at the level of the adjacent cells constituting these accumulators.
• the general field of the invention can be defined as that of energy storage devices, in particular that of electrochemical accumulators.
• Electrochemical accumulators operate on the principle of electrochemical cells capable of delivering an electric current thanks to the presence in each of them of a pair of electrodes (respectively, a positive electrode and a negative electrode) separated by an electrolyte, the electrodes comprising specific materials capable of reacting according to an oxidation-reduction reaction, whereby there is production of electrons at the origin of the electric current and production of ions which will circulate from one electrode to the other by through an electrolyte.
• Ni-MH accumulators using metal hydride and nickel oxyhydroxide as active electrode materials Ni-MH accumulators using metal hydride and nickel oxyhydroxide as active electrode materials
• Ni-MH accumulators using, in particular a metal hydride and nickel oxyhydroxide as active electrode materials
• Ni-MH accumulators using, in particular a metal hydride and nickel oxyhydroxide as active electrode materials such as Ni-MH accumulators using, in particular a metal hydride and nickel oxyhydroxide as active electrode materials
• Ni-Cd accumulators using cadmium and nickel oxyhydroxide as active electrode materials or nickel-zinc accumulators using nickel hydroxide and zinc oxide as active electrode materials
• nickel-zinc accumulators using nickel hydroxide and zinc oxide as active electrode materials
• -accumulators operating on the principle of insertion-disinsertion of an alkaline or alkaline-earth element intervening at the level of the electrodes (and more specifically, active materials of electrodes), accumulators subscribing to this principle and currently used being the lithium-ion type accumulators using, in whole or in part, lithiated materials to constitute the active electrode materials.
• lithium-ion accumulators make it possible to obtain densities of mass and volume energy (which can be greater than 180 Wh.kg 1 ) significantly greater than those of Ni-MH and Ni-Cd accumulators (which can range from 50 and 100 Wh.kg 1 ) and Lead acid (which can range from 30 to 35 Wh.kg 1 ).
• monopolar that is to say an architecture in which an accumulator comprises only one electrochemical cell which uses, for example, a positive electrode based on lithiated cobalt oxide (LiCo0 2 ) and a negative electrode based on graphite, separated from each other by an electrolyte conducting lithium ions, the nominal voltage of these accumulators being l of 3.6 V.
• Accumulators with bipolar architecture include, as illustrated in FIG. 1 attached in the appendix, two terminal current collecting substrates 1, 3 and a stack of electrochemical cells (Ci, C 2 , ..., C n ) which each comprise, a positive electrode 5, a negative electrode 7 and a separator 9 interposed between the positive electrode and the negative electrode in the presence of a lithium ion conductive electrolyte, when the accumulator is a lithium-ion accumulator, stack in which the electrochemical cells are separated from each other by a current collector substrate, called bipolar current collector substrate 11, which is in the form of a sheet, one face of which is in contact with the negative electrode of an electrochemical cell while that the other face is in contact with the positive electrode of the adjacent electrochemical cell.
• bipolar current collector substrate 11 which is in the form of a sheet, one face of which is in contact with the negative electrode of an electrochemical cell while that the other face is in contact with the positive electrode of the adjacent electrochemical cell.
• the bipolar architecture thus corresponds to a series connection of several accumulators via so-called bipolar current collecting substrates, which makes it possible to dispense with external connectors, which are necessary for assembling monopolar accumulators in series. It therefore leads to lighter systems than those resulting from a series assembly of monopolar accumulators, thus increasing the energy density.
• the final voltage of the accumulator can be easily adjustable and can be very high, if desired.
• the essential problem of bipolar technology lies in the difficulty of confining, in each cell, the liquid electrolyte, in order to have an assembly comprising identical cells in series while remaining independent of each other. Indeed, if the liquid electrolyte contained in a cell does not remain confined in it but spreads in the adjacent cells, there can occur a phenomenon of ionic short circuit which can cause an imbalance in the stack and in particular a defectiveness of all or part of the cells thus generating rapid degradation of the whole.
• sealing can be ensured by creating a physical barrier to the movement of the electrolyte, this physical barrier being able to be obtained, for example, by the following means: a seal made of a thermoset resin of the epoxy resin type, or of an adhesive of the acrylic adhesive type, which is deposited on the periphery of the stack of electrochemical cells as described, for example, in international application PCT WO 03 / 047021 and illustrated in Figure 1 by reference 13;
• a glass or a ceramic conducting lithium ions in a purely solid form for example, a thin layer deposited by chemical vapor deposition (CVD) such as a LIPON layer, or a layer of a material composite comprising a polymer matrix, for example, made of polyvinylidene fluoride, and a filler consisting of a lithiated oxide, such as LbLasZ ⁇ O ⁇ ;
• CVD chemical vapor deposition
• LIPON layer a layer of a material composite comprising a polymer matrix, for example, made of polyvinylidene fluoride, and a filler consisting of a lithiated oxide, such as LbLasZ ⁇ O ⁇ ;
• a dry solid electrolyte composed of a polymer of the polyethylene oxide (POE) type and of a lithium salt, for example, lithium trifluorosulfonylimide (LiTFSI).
• the inventors have set themselves the objective of proposing new accumulators with bipolar architecture using a liquid electrolyte but the leakage of which is controlled without needing to resort to the use a physical barrier to flow, such as gaskets disposed at the periphery of the electrochemical cells. Furthermore, the inventors set themselves the objective of proposing new accumulators with bipolar architecture exhibiting, in addition to excellent confinement of the electrolyte, efficient and stable electrochemical performance even after a high number of operating cycles (or in others terms, of charge-discharge cycles).
• the authors of the present invention have been able to access the abovementioned objectives by installing gel cells in accumulators with bipolar architecture, which make it possible to confine a liquid electrolyte without harming its conductivity properties and without the risk of it leaking.
• the accumulators with bipolar architecture of the invention can be thus defined as being accumulators with bipolar architecture which comprise two terminal current collectors between which is disposed a stack of n electrochemical cells, n being an integer at least equal to 2, in which : - each electrochemical cell comprises a positive electrode, a negative electrode and an ion-conducting membrane which is interposed between the positive electrode and the negative electrode and comprises a liquid electrolyte included in the electrodes (i.e., the positive electrode and the negative electrode) and the ion conducting membrane;
• n-1 bipolar current collectors n-1 bipolar current collectors
• the positive electrode and the negative electrode of each electrochemical cell are gelled electrodes comprising a composite material comprising a polymer matrix made of at least one gelling polymer (FF), an active electrode material and optionally one or more electronic conductive additives, the polymer matrix trapping the liquid electrolyte, the gelling polymer (s) being chosen from fluorinated polymers comprising at least one repeating unit resulting from the polymerization of a fluorinated monomer and, preferably, at least one repeating unit resulting from the polymerization of a monomer comprising at least one carboxylic acid group, optionally in the form of a salt.
• FF gelling polymer
• the gelling polymer (s) being chosen from fluorinated polymers comprising at least one repeating unit resulting from the polymerization of a fluorinated monomer and, preferably, at least one repeating unit resulting from the polymerization of a monomer comprising at least one carboxylic acid group, optionally in the form of a salt.
• positive electrode is meant, conventionally, in what precedes and what follows, the electrode which acts as cathode, when the accumulator delivers current (that is to say when it is in the process of discharging ) and which acts as an anode when the battery is in the process of charging.
• negative electrode By negative electrode is meant, conventionally, in what precedes and what follows, the electrode which acts as anode, when the accumulator delivers current (i.e. when it is in the process of discharge) and which acts as a cathode, when the accumulator is in the process of charging.
• repetitive unit is meant, conventionally, in what precedes and what follows, a bivalent unit resulting from the polymerization of a monomer and which is repeated in the polymer.
• the inventor's accumulators comprise, as an essential element, gelled electrodes (namely, the positive and negative electrodes of each compartment) comprising (or even consisting of) a composite material comprising (or even consisting of ) a polymer matrix in at least one gelling polymer (FF), an active electrode material and optionally one or more electronic conductive additives, the polymer matrix trapping the liquid electrolyte, the gelling polymer (s) being chosen (s) ) from fluorinated polymers comprising at least one repeating unit resulting from the polymerization of a fluorinated monomer and, preferably, at least one repeating unit resulting from the polymerization of a monomer comprising at least one carboxylic acid group, optionally in the form of 'a salt.
• gelled electrodes namely, the positive and negative electrodes of each compartment
• the ingredients constituting the positive electrode and the negative electrode are identical, apart from the nature of the active electrode material.
• the gelling polymer (s) (FF) are chosen from fluorinated polymers comprising at least one repeating unit resulting from the polymerization of a fluorinated monomer and, preferably, at least one repeating unit resulting from the polymerization of a monomer comprising at least one carboxylic acid group, optionally in the form of a salt.
• repeating unit or units resulting from the polymerization of a fluorinated monomer and, where appropriate, the repeating unit or units resulting from the polymerization of a monomer comprising at least one carboxylic acid group, optionally in the form of 'a salt are chemically different repeating units and, in particular, the repeating unit or units resulting from the polymerization of a fluorinated monomer do not comprise any carboxylic acid group (s), optionally in the form of a salt.
• the repeating unit or units resulting from the polymerization of a fluorinated monomer may be, more specifically, one or more repeating units resulting from the polymerization of one or more ethylenic monomers comprising at least one atom of fluorine and optionally one or more other halogen atoms of the examples of monomers of this type being the following:
• -perfluoroolefins C 2 -Cs such as tetrafluoroethylene, hexafluoropropene (also known by the abbreviation HFP);
• C 2 -C 8 fluoroolefins such as vinylidene fluoride, vinyl fluoride, 1,2-difluoroethylene and trifluoroethylene;
• -perfluoroalkylethylenes of formula CH 2 CHR 1 , in which R 1 is a C 1 -C 6 perfluoroalkyl group;
• -des monomers of the formula CF 2 CFOR 3, wherein R 3 is alkyl C 1 -C 12 alkoxy, C 1 -C 12 or a (per) fluoro- C 1 -C 12, such that a perfluoro-2-propoxypropyl group; and or
• -monomers of formula CF2 CF0CF20R 4 , in which R 4 is a fluoro- or perfluoroalkyl group C 1 -C 6 , such as CF 2 , C 2 F 5 , C 3 F 7 or a fluoro- or perfluoroalkoxy group C 1 -C 6 , such as -C 2 F 5 -O-CF 3 .
• the gelling polymer (s) (FF) may comprise, as repeating unit (s) resulting from the polymerization of a fluorinated monomer, a repeating unit resulting from the polymerization of a monomer from the category C 2 -C 8 perfluoroolefins, such as hexafluoropropene and a repeating unit resulting from the polymerization of a monomer from the category of hydrogenated C 2 -C 8 fluoroolefins, such as vinylidene fluoride.
• the repeating unit or units resulting from the polymerization of a monomer comprising at least one carboxylic acid group, optionally in the form of a salt may be, more specifically, one or more repeating units resulting from the polymerization of a monomer of formula ( I) following:
• R 5 to R 7 represent, independently of one another, a hydrogen atom or a C 1 -C 3 alkyl group and R 8 represents a hydrogen atom or a monovalent cation (for example, an alkaline cation, an ammonium cation), particular examples of monomers of this type being acrylic acid or methacrylic acid.
• Particular gelling polymers which can be used in the context of the invention may be polymers comprising a repeating unit derived from the polymerization of vinylidene fluoride, a repeating unit resulting from the polymerization of a monomer comprising at least one carboxylic acid group, such as acrylic acid and optionally a repeating unit resulting from the polymerization of a fluorinated monomer different from vinylidene fluoride (and more specifically, a repeating unit resulting from the polymerization of hexafluoropropene).
• a repeating unit derived from the polymerization of vinylidene fluoride a repeating unit resulting from the polymerization of a monomer comprising at least one carboxylic acid group, such as acrylic acid and optionally a repeating unit resulting from the polymerization of a fluorinated monomer different from vinylidene fluoride (and more specifically, a repeating unit resulting from the polymerization of hexafluoropropene).
• gelling polymers which can be used in the context of the invention are gelling polymers, the aforementioned repeating units of which result from polymerization:
• the gelling polymer (s) (FF) advantageously have an intrinsic viscosity measured at 25 ° C. in N, N-dimethylformamide ranging from 0.1 to 1.0 L / g, preferably 0.25 at 0.45 L / g.
• the intrinsic viscosity is determined by the equation below based on the duration of fall, at 25 ° C, of a solution obtained by dissolving the polymer concerned in a solvent (N, N-dimethylformamide) at a concentration of approximately 0.2 g / dL using an Ubbelhode viscometer: in which :
• -h G corresponds to the relative viscosity, that is to say the ratio between the duration of fall of the solution and the duration of fall of the solvent;
• - H sP corresponds to the specific viscosity, that is to say h G - 1; -G corresponds to an experimental factor fixed at 3 for the polymer concerned.
• Each of the electrodes comprises an active electrode material, namely a material capable of inserting and deinserting, in its structure, metal ions, such as alkaline ions (for example, lithium, when the accumulator is a lithium accumulator , sodium, when the accumulator is a sodium accumulator, or potassium, when the accumulator is a potassium accumulator), alkaline earth ions (for example, magnesium, when the accumulator is a magnesium accumulator ).
• metal ions such as alkaline ions (for example, lithium, when the accumulator is a lithium accumulator , sodium, when the accumulator is a sodium accumulator, or potassium, when the accumulator is a potassium accumulator), alkaline earth ions (for example, magnesium, when the accumulator is a magnesium accumulator ).
• the nature of the active material depends, of course, on its destination, namely whether it is intended for a positive electrode or a negative electrode.
• active electrode materials capable of entering into the constitution of a positive electrode of a lithium accumulator mention may be made of:
• -metal chalcogenides of formula LiMCh in which M is at least one metallic element chosen from the transition metallic elements, such as Co, Ni, Fe, Mn, Cr, V and Q is a chalcogen, such as O or S, the preferred metal chalcogenides being those of formula UMO2, with M being as defined above, such as, preferably, UC0O2, LiNi0 2 , LiNi x Coi- x 0 2 (with 0 ⁇ x ⁇ 1), LiMn 2 0 4 of spinel structure;
• MiM2 (J0 4) f EI- f wherein Mi is lithium, which may be partially substituted by another alkaline element up to a substitution rate of less than 20%
• M2 is a transition metal element of oxidation state +2 chosen from Fe, Mn, Ni and combinations thereof, which may be partially substituted by one or more other metallic elements additional with degree (s) of oxidation (s) between +1 and +5 up to a substitution rate of less than 35%
• J0 4 is an oxyanion in which J is chosen from P, S, V, Si, Nb, Mo and the combinations of these
• E is a fluoride, hydroxide or chloride anion
• f is the molar fraction of the oxyanion J0 4 and is generally between 0.75 and 1 (including 0.75 and 1).
• the lithiated or partially lithiated materials can advantageously be based on phosphorus (which means, in other words, that the oxyanion corresponds to the formula P0 4 ) and can have a structure of the ordered olivine type or changed.
• the lithiated or partially lithiated materials can correspond to the specific formula Li 3-x M ' y M " 2 -y (J0 4 ) 3 , in which 0 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 2, M' and M "represent identical or different metallic elements, at least one of M ′ and M" being a metallic transition element, J0 4 is preferably P0 4 , which can be partially substituted by another oxyanion with J being chosen from S, V, Si, Nb, Mo and the combinations thereof.
• the lithiated or partially lithiated materials can correspond to the formula Li (Fe x Mni- x ) P0 4 , in which 0 ⁇ x £ l and, preferably, x is equal to 1 (which means, in other words, that the corresponding material is LiFeP0 4 ).
• active electrode materials capable of entering into the constitution of a negative electrode of a lithium accumulator mention may be made of:
• carbonaceous materials such as graphitic carbon capable of intercalating lithium, which may typically exist in the form of a powder, flakes, fibers or spheres (for example, microbeads of mesocarbon);
• lithiated titanium oxides such as an oxide of formula Li ( 4-x) M x TisOi2 or Li 4 M y Ti ( 5- y) Oi2 in which x and y range from 0 to 0.2, M represents an element chosen from Na, K, Mg, Nb, Al, Ni, Co, Zr, Cr, Mn, Fe, Cu, Zn, Si and Mo, a specific example being Li 4 Ti50i2, these oxides being insertion materials lithium with a low level of physical expansion after inserting lithium;
• - non-lithiated titanium oxides such as T1O2
• lithium silicides generally known under the terminology of lithium silicides and advantageously having high Li / Si ratios, such as Li 4.4 Si;
• lithium-germanium alloys such as those comprising crystalline phases of formula Li 4.4 Ge.
• the positive electrode or the negative electrode may include electronic conductive additives, that is to say additives capable of imparting to the electrode, in which they are incorporated, a conductivity.
• these additives can be, for example, carbonaceous materials such as carbon black, carbon nanotubes, carbon fibers (in particular, carbon fibers obtained in the vapor phase known under the abbreviation VGCF), graphite in powder form, graphite fibers and mixtures thereof.
• a negative electrode comprises, as active material, carbonaceous materials, such as graphite
• the negative electrode can advantageously be devoid of electronic conductive additive (s).
• all the negative electrodes of the accumulator respond to the same specificities (namely, in terms of composition and dimensions) just as all the positive electrodes of the accumulator also respond to the same specificities in terms of composition and dimensions.
• the positive electrode or the negative electrode they comprise a liquid electrolyte trapped within the polymer matrix.
• the liquid electrolyte trapped within the membrane is, conventionally, an ion-conducting electrolyte, which can comprise (or even consists of) at least one organic solvent, at least one metal salt and optionally a compound from the family of compounds vinyl.
• the organic solvent (s) can be carbonate solvents and, more specifically:
• cyclic carbonate solvents such as ethylene carbonate (symbolized by the abbreviation EC), propylene carbon (symbolized by the abbreviation PC), butylene carbonate, vinylene carbonate, fluoroethylene carbonate, fluoropropylene carbonate and mixtures thereof;
• - linear carbonate solvents such as diethyl carbonate (symbolized by the abbreviation DEC), dimethyl carbonate (symbolized by the abbreviation DMC), ethylmethyl carbonate (symbolized by the abbreviation EMC) and mixtures of these.
• DEC diethyl carbonate
• DMC dimethyl carbonate
• EMC ethylmethyl carbonate
• the organic solvent (s) can also be ester solvents (such as ethyl propionate, n-propyl propionate), nitrile solvents (such as acetonitrile) or ether solvents (such as dimethyl ether, 1 , 2-dimethoxyethane).
• ester solvents such as ethyl propionate, n-propyl propionate
• nitrile solvents such as acetonitrile
• ether solvents such as dimethyl ether, 1 , 2-dimethoxyethane
• the organic solvent (s) may also be ionic liquids, that is to say conventionally compounds formed by the combination of a positively charged cation and a negatively charged anion, which is in the liquid state at temperatures below 100 ° C under atmospheric pressure.
• ionic liquids can include:
• a cation chosen from the imidazolium, pyridinium, pyrrolidinium, piperidinium cations, said cations being optionally substituted with at least one alkyl group comprising from 1 to 30 carbon atoms;
• an anion chosen from halide anions, perfluorinated anions, borates.
• the cation can be chosen from the following cations:
• R 13 and R 14 represent, independently of one another, a C 1 -C 6 alkyl group and R 15 , R 16 , R 17 and R 18 represent, independently of one another, an atom hydrogen or a C 1 -C 30 alkyl group, preferably a C 1 -C 6 alkyl group, more preferably a C 1 -C 6 alkyl group;
• R 19 and R 20 represent, independently of one another, a C 1 -C 6 alkyl group and R 21 , R 22 , R 23 , R 24 and R 25 represent, independently of each other , a hydrogen atom or a C 1 -C 30 alkyl group, preferably a C 1 -C 6 alkyl group, more preferably a C 1 -C 6 alkyl group.
• the positively charged cation can be chosen from the following cations:
• the negatively charged anion can be chosen from
• a specific ionic liquid which can be used according to the invention can be an ionic liquid composed of a cation of formula (II-A) as defined above and an anion of formula (SO 2 CF 3 ) 2 N, PF 6 or BF 4 .
• the metal salt (s) can be chosen from the salts of the following formulas: Mel, Me (PFe) n , Me (BF 4 ) n, Me (CI0 4 ) n, Me (bis (oxalato) borate) n (which may be designated by the abbreviation Me (BOB) n ), MeCF3S03, Me [N (FS0 2 ) 2] n, Me [N (CF 3 S0 2 ) 2] n, Me [N (C 2 F 5 S0 2 ) 2 ] n, Me [N (CF3S0 2 ) (R F S0 2 )] n , in which R F is a group - C 2 F 5 , -C 4 Fg or - CF30CF 2 CF3, Me (AsFe) n , Me [C (CF 3 S0 2 ) 3 ] n , Me 2 S n , Me (CeF 3 N 4 ) (C 6 F3N 4 corresponding to 4,5
• the salt is preferably LÎPF 6 -
• the concentration of the metal salt in the liquid electrolyte is, advantageously, at least 0.01 M, preferably at least 0.025 M and, more preferably, at least 0.05 M and, advantageously, d '' at most 5 M, preferably at most 2 M and more preferably at most IM.
• liquid electrolyte may comprise an additive belonging to the category of vinyl compounds, such as vinylene carbonate, this additive being included in the electrolyte at a content not exceeding 5% by mass of the total mass of the electrolyte.
• a liquid electrolyte which can be used in the accumulators of the invention, in particular when it is a lithium-ion accumulator, is an electrolyte comprising a mixture of carbonate solvents (for example, a mixture of cyclic carbonate solvents, such than a mixture of ethylene carbonate and propylene carbonate and present, for example, in identical volume), a lithium salt, for example, LÎPF 6 (for example, IM) and vinylene carbonate (for example, present at 2% by mass relative to the total mass of the liquid electrolyte).
• a mixture of carbonate solvents for example, a mixture of cyclic carbonate solvents, such than a mixture of ethylene carbonate and propylene carbonate and present, for example, in identical volume
• a lithium salt for example, LÎPF 6 (for example, IM)
• vinylene carbonate for example, present at 2% by mass relative to the total mass of the liquid electrolyte
• the positive electrode (s) and / or the negative electrode (s) may have a thickness ranging from 2 to 500 ⁇ m, preferably from 10 to 400 ⁇ m and, more preferably, a thickness ranging from 50 to 300 ⁇ m.
• each electrochemical cell has a membrane disposed between the positive electrode and the negative electrode and therefore allows physical separation between them. It can thus also be qualified as a separator.
• This membrane allows, in a conventional manner, also an ionic conduction (namely, the passage of ions from the negative electrode to the positive electrode and vice versa, depending on whether one is in the charge or discharge process) , which allows to qualify it as an ion conducting membrane.
• it advantageously makes it possible to confine a liquid electrolyte, which liquid electrolyte advantageously responding to the same specificities as that used in the constitution of the gelled electrodes.
• each membrane advantageously comprises an organic part comprising (or consisting of) at least one fluoropolymer (F) comprising at least one repeating unit resulting from the polymerization of a fluorinated monomer and at least one repeating unit originating from the polymerization of a monomer comprising at least one hydroxyl group, optionally in the form of a salt, and comprising an inorganic part formed, in whole or in part, of one or more oxides of at least one element M chosen from Si, Ti and Zr and combinations thereof and further comprises a liquid electrolyte, which is advantageously identical to that included in the gelled electrodes.
• F fluoropolymer
• the liquid electrolyte is, advantageously, confined or trapped within the material constituting the membrane and can respond to the same specific characteristics as those set out above with regard to gelled electrodes, in terms of ingredients (organic solvents, salts, concentrations ).
• the repeating unit or units resulting from the polymerization of a fluorinated monomer may be, more specifically, one or more repeating units resulting from the polymerization of one or more ethylenic monomers comprising at least one atom of fluorine and optionally one or more other halogen atoms of the examples of monomers of this type being the following: - C 2 -C 8 perfluoroolefins, such as tetrafluoroethylene, hexafluoropropene (also known by the abbreviation HFP);
• C 2 -C 8 fluoroolefins such as vinylidene fluoride, vinyl fluoride, 1,2-difluoroethylene and trifluoroethylene;
• -perfluoroalkylethylenes of formula CH 2 CHR 1 , in which R 1 is a C 1 -C 6 perfluoroalkyl group;
• fluoroolefins comprising one or more other halogen atoms (such as chlorine, bromine, iodine), such as chlorotrifluoroethylene;
• fluoroalkylvinylethers of formula CF 2 CFOR 2 , in which R 2 is a fluoro- or perfluoroalkyl group C 1 -C 6 , such as CF 3 , C 2 F 5 , C 3 F 7 ;
• -des monomers of the formula CF 2 CFOR 3, wherein R 3 is alkyl C 1 -C 12 alkoxy, C 1 -C 12 or a (per) fluoro- C 1 -C 12, such that a perfluoro-2-propoxypropyl group; and or
• -monomers of formula CF 2 CF0CF 2 0R 4 , in which R 4 is a fluoro- or C 1 -C 6 perfluoroalkyl group, such as CF 2 , C 2 F 5 , C 3 F 7 or a fluoro- group or C 1 -C 6 perfluoroalkoxy, such as -C 2 F 5 -O-CF 3 .
• the fluoropolymer (F) can comprise, as repeating units resulting from the polymerization of a fluorinated monomer, a repeating unit resulting from the polymerization of a monomer from the category of C 2 -C 8 perfluoroolefins, such as hexafluoropropene and a repeating unit resulting from the polymerization of a monomer from the category of C 2 -C 8 hydrogenated fluoroolefins, such as vinylidene fluoride.
• the repeating unit or units resulting from the polymerization of a monomer comprising at least one hydroxyl group, optionally in the form of a salt may be, more specifically, one or more repeating units originating from the polymerization of a monomer of formula (IV) below:
• R 9 to R 11 represent, independently of one another, a hydrogen atom or a C 1 -C 3 alkyl group and R 12 is a C 1 -C 5 hydrocarbon group comprising at least one hydroxyl group
• examples of monomers of this type being hydroxyethyl (meth) acrylate monomers, hydroxypropyl (meth) acrylate monomers.
• the fluoropolymer (F) can comprise, as a repeating unit resulting from the polymerization of a monomer comprising at least one hydroxyl group, a repeating unit resulting from the polymerization of one of the monomers of formulas (V) to ( Vil) following:
• fluorinated polymers (F) which can be used in the context of the invention to form the membranes can be polymers comprising, as repeating units resulting from the polymerization of a fluorinated monomer, a repeating unit resulting from the polymerization of a monomer from the category of C 2 -Cs perfluoroolefins, such as hexafluoropropene and a repeating unit resulting from the polymerization of a monomer from the category of C2-C8 hydrogenated fluoroolefins, such as vinylidene fluoride, and comprising, as a repeating unit resulting from the polymerization of a monomer comprising at least one hydroxyl group, a repeating unit resulting from the polymerization of a monomer of formula (IV) previously defined and, more specifically still, a polymer whose repeating units mentioned above are from polymerization:
• the inorganic part formed, at least in part, of one or more oxides of at least one element M chosen from Si, Ti and Zr and the combinations of these is, in whole or in part, chemically linked to the organic part via hydroxyl groups.
• the membranes of the invention advantageously have a surface which completely covers the surface of the negative electrodes, with which they are in contact (so as to ensure a frank separation with the positive electrode) with, however, on condition that they do not exceed the face of the current collector accommodating the negative electrode, except taking the risk of creating an ionic short-circuit by contacting the membrane of the adjacent cell during the process of assembling the various constituent elements of the accumulators.
• the accumulators of the invention are accumulators with bipolar architecture, which presupposes the presence of collector (s) of bipolar current (s) between two adjacent cells.
• the bipolar current collector when the accumulator has only two cells
• the bipolar current collectors when the accumulator has more than two cells
• an electrochemical cell is adjacent to another electrochemical cell when it immediately precedes or follows it in the stack and is therefore only separated from it by a bipolar current collector.
• the accumulators of the invention also include terminal current collectors generally positioned at the ends of the stack and which receive, on one of their faces, an electrode layer belonging to a terminal cell (this electrode layer being a layer positive electrode or a negative electrode layer depending on the desired polarity), this electrode layer being, conventionally, of identical constitution to that of an electrode layer of the same polarity associated with a bipolar current collector.
• the current collector (s), whether terminal or bipolar may be monolayer, in which case they are preferably made of aluminum foil, copper or an aluminum alloy, or else bilayer, in which case they are preferably made of an aluminum sheet associated with a layer of copper or else of two joined sheets (for example, an aluminum sheet attached to a copper sheet). They have, for example, a thickness of 20 mhi.
• the current collector (s), whether terminal or bipolar consist of a monolayer sheet, such as an aluminum sheet, in particular when the active material of the positive electrode is LiNio, 33 Mno, 33 Coo, 33 0 2 and the active material of the negative electrode is LUTisO ⁇ .
• They can advantageously be bilayer, for example, resulting from the juxtaposition of an aluminum foil and a copper foil, in particular when the active material of the positive electrode is LiNio, 33 Mno, 33 Coo, 33 0 2 (the resulting positive electrode being affixed to the face of the collector formed by the aluminum foil) and the active material of the negative electrode is graphite (the resulting negative electrode being affixed to the face of the collector constituted by the copper sheet).
• each pair of current collectors facing each other via a free edge and / or a tongue may comprise, for at least one of them, a layer of insulating material covering all or part of the free edge and / or the tongue.
• insulating material makes it possible to electronically isolate these collectors (and in particular to avoid a short circuit, if it comes under the pressure of the stack to be in contact with each other. 'other).
• This insulating material affixed in the form of a layer (s) fulfills the insulating function normally assigned to the seal (s) present at each cell in conventional bipolar accumulators, these seals not being present. for the accumulators of the invention, because the liquid electrolyte is sufficiently confined by the choice of the electrodes and the membranes described above.
• the layers of insulating material can take different positions.
• FIG. 2 representing, in profile, a bipolar accumulator comprising two cells (the references 15 and 17 respectively illustrating the negative electrodes and the electrodes positive of each cell, the reference 19, the membranes of each cell and the references 21, 23 and 25 respectively illustrating the negative terminal current collector, the bipolar current collector and the positive terminal current collector), provision is made for affix a layer of insulating material (respectively referenced 27 and 29) on the tabs (respectively referenced 20 and 24) of each terminal current collector on the inner face of these (that is to say the faces located in screws -a-vis).
• FIG. 3 representing, in profile, a bipolar accumulator comprising two cells (the references 15 and 17 respectively illustrating the negative electrodes and the positive electrodes of each cell, the reference 19, the membranes of each cell and references 21, 23 and 25 respectively illustrating the negative terminal current collector, the bipolar current collector and the positive terminal current collector), provision is made to affix:
• a bipolar accumulator comprising three cells (the references 15 and 17 respectively illustrating the negative electrodes and the positive electrodes of each cell, the reference 19, the membranes of each cell and references 21, 23 and 25 respectively illustrating the negative terminal current collector, the bipolar current collectors and the positive terminal current collector), it is intended to affix:
• each bipolar current collector accommodating the positive electrode; and a layer of insulating material (referenced 35) on the tongue (referenced 37) of the positive terminal current collector 25 opposite the face of the bipolar current collector accommodating the negative electrode.
• the layers of insulating material are positioned so as to avoid any direct contact between the metal parts (free edge and / or tongues) of the faces of the current collectors. located opposite.
• the insulating material used may consist of a plastic material such as Kapton ®, polypropylene, and may be affixed to the desired portions by gluing, coating, printing or simply contacting.
• the accumulators of the invention may include packaging intended, as its name suggests, to package the various constituent elements of the stack.
• This packaging can be flexible (in which case it is, for example, produced from a laminated film comprising a screen in the form of aluminum foil which is coated on its outer surface with a layer of polyethylene terephthalate ( PET) or a polyamide and which is coated on its inner surface with a layer of polypropylene (PP) or polyethylene (PE)) or else rigid (in which case it is, for example, made of a light and inexpensive metal such than stainless steel, aluminum or titanium, or in a thermoset resin such as an epoxy resin) depending on the type of application targeted.
• PET polyethylene terephthalate
• PE polyethylene
• rigid in which case it is, for example, made of a light and inexpensive metal such than stainless steel, aluminum or titanium, or in a thermoset resin such as an epoxy resin
• n can be between 2 and 20 with the accumulators of the invention.
• the accumulators of the invention can find application in the production of electric or hybrid vehicles, of stationary storage devices energy and portable electronic devices (phones, touch pads, computers, cameras, camcorders, portable tools, sensors, etc.).
• the accumulators of the invention can, moreover, be adapted to different types of formats, such as the planar format, for example, of the button cell type; cylindrical formats; wound or spiral formats; the prismatic format.
• the accumulators of the invention can be prepared by a process comprising a step of assembling the basic elements, which are the bipolar current collector (s) coated on two opposite faces, respectively, by a positive electrode and a negative electrode (the number of current collectors to be assembled corresponding to (n-1) with n corresponding to the number of cells of the accumulator), the membranes as defined above and the terminal current collectors coated on one of their faces, for the one with a negative electrode and the other with a positive electrode.
• the basic elements which are the bipolar current collector (s) coated on two opposite faces, respectively, by a positive electrode and a negative electrode (the number of current collectors to be assembled corresponding to (n-1) with n corresponding to the number of cells of the accumulator), the membranes as defined above and the terminal current collectors coated on one of their faces, for the one with a negative electrode and the other with a positive electrode.
• Each membrane can be interposed between the positive electrode and the negative electrode of each cell, which means, in other words, that it preexists the formation of this stack or it can be deposited (by any deposition techniques solution, such as coating, pouring or printing) on one side of one of the positive or negative electrodes of each cell.
• the various basic elements can be prepared before assembly, in particular as regards the positive and negative electrodes.
• the positive and negative electrodes can be produced by depositing a composition comprising the constituent ingredients of the electrodes (gelling polymer (FF), active material, liquid electrolyte and optionally at least one electronic conductive additive as defined above. ) on the current collectors by a solution deposition technique (for example, coating, printing, pouring) followed by drying.
• a solution deposition technique for example, coating, printing, pouring
• the positive and negative electrodes can be prepared by a process comprising the following steps:
• FF gelling polymer
• the active electrode material is an active material with a positive electrode, when the process relates to the preparation of a positive electrode or is an active material with a negative electrode, when the method relates to the preparation of a negative electrode;
• step (iii) applying the composition of step (ii) to the current collector of step (i), whereby there results an assembly comprising the current collector coated with at least one layer of said composition ;
• step (iv) drying the assembly resulting from step (iii).
• the composition can be applied to a current collector by all types of application methods, for example, by casting, printing or coating, for example, with a roller.
• Step (iii) can typically be repeated one or more times, depending on the thickness of the electrode desired.
• the ingredients of the composition can correspond to the same variations as those already defined for these same ingredients in the context of the description of the electrodes as such.
• composition advantageously comprises an organic solvent chosen so as to allow the solubilization of the gelling polymer (s), this organic solvent can be that of the liquid electrolyte or can be added in addition to the other ingredients mentioned above.
• the various current collectors can be provided with metal tabs to ensure the recovery of current, in the case of terminal current collectors or for the control of the voltage, in the case of current collectors bipolar and can be coated with a layer of insulating material on their free edge and / or on the tabs as already described above.
• the membranes when they meet the specific definition given above, are capable of being obtained by a process comprising a hydrolysis-condensation step, in the presence of a liquid electrolyte and a fluorinated polymer (F) such as defined above, of at least one organometallic compound comprising a metallic element chosen from Si, Ti, Zr and combinations thereof, a reaction occurring, advantageously between the organometallic compound and the fluorinated polymer (F).
• the membranes can be produced by a process comprising the following specific steps:
• m is an integer ranging from 1 to 3
• A is a metallic element chosen from Si, Ti, Zr and the combinations thereof
• Y is a hydrolyzable group
• This type of process falls under the category of processes of the sol-gel type, since it involves organometallic compounds comprising hydrolysable groups and a hydrolysis-condensation stage of these compounds to form an inorganic part.
• the hydrolyzable group for the compound M1 is preferably chosen so as to allow the formation of an —OA— bond, this group being able to be chosen from halogen atoms (preferably chlorine), alkoxy groups, acyloxy groups and hydroxyl groups.
• the compound M1 can correspond to the following formula:
• R A is a metallic element chosen from Si, Ti, Zr and the combinations of these
• R A is a hydrocarbon group, linear or branched, comprising from 1 to 12 carbon atoms
• R B are hydrocarbon groups, more specifically, alkyl groups, linear or branched and comprising from 1 to 5 carbon atoms (for example, methyl or ethyl groups).
• trimethoxysilylmethylisocyanate triethoxysilylmethylisocyanate, trimethoxysilylethylisocyanate, triethoxysilylethylisocyanate, trimethoxysilylpropylisocyanate, triethoxysilylpropylisocyanate, trimethoxysilylbutylisocyanate, triethoxysilylbutylisocyanate, trimethoxysilylpentylisocyanate, triethoxysilylpentylisocyanate triethyloxisilylpentylisocyanate
• the hydrolyzable group for the compound M2 is preferably chosen so as to allow the formation of a bond -OA-, this group being able to be chosen from atoms halogen (preferably chlorine), alkoxy groups, acyloxy groups and hydroxyl groups.
• TMS tetramethoxysilane
• TEOS tetraethoxysilane
• the reaction step (ii) is carried out, generally, at a temperature ranging from 20 to 100 ° C, preferably from 20 to 90 ° C and more preferably from 20 to 60 ° C and, preferably, under inert gas atmosphere (such as a flow of argon).
• This reaction step (ii) and the subsequent step (iii) can be carried out in the presence of a condensation catalyst, which can be introduced during step (i).
• the condensation catalyst can be an organostannic compound.
• step (i) It can be introduced, during step (i), up to 0.1% to 50% by mole, preferably from 1 to 25% by mole, more preferably from 5 to 15% by mole relative to the total number of moles of compound Ml and, where appropriate, of compound
• organotin compounds mention may be made of dibutyltin dilaurate, dibutyltin oxide, tributyltin oxide, dioctyltin oxide, tributyltin chloride and tributyltin fluoride.
• the hydrolysis-condensation stage (iii) can be carried out at ambient temperature or by heating to a temperature below 100 ° C., the choice of temperature being dependent on the boiling point of the liquid electrolyte.
• This hydrolysis-condensation step can be carried out in the presence of an acid catalyst, which can be added during one of steps (i) to (iii), for example, up to 0.5 to 10% by mass, preferably from 1 to 5% by mass on the total basis of the composition.
• an acid catalyst which can be added during one of steps (i) to (iii), for example, up to 0.5 to 10% by mass, preferably from 1 to 5% by mass on the total basis of the composition.
• This acid catalyst can in particular be an organic acid, such as formic acid.
• the method can comprise a step (iv) of shaping the composition in the form of a membrane, this shaping step can be carried out concomitantly with the hydrolysis-condensation step (iii), this step shaping can be performed for all known techniques of membrane formation involving a composite material, an example of a suitable technique being the technique of deposition by extrusion slot, better known under the English name "slot-die coating".
• the method for preparing the accumulators of the invention may include a step of placing a packaging around the accumulator, this positioning being able to be carried out by heat sealing in the case of flexible packaging and by welding. laser in the case of rigid packaging.
• FIGS. 2 to 4 already commented on, schematically represent views in longitudinal section of accumulators according to the invention
• - Figure 5 is a graph, obtained in the context of the tests of Example 1 and illustrating the evolution of the voltage U (in V) as a function of time t (in h) with curves a) and b) for the first cell and the second cell of the accumulator and the curve c) for the accumulator as such;
• FIG. 6 is a graph obtained in the context of the tests of Example 1 and illustrating the evolution of the discharge capacity C (in mAh) as a function of the number of cycles N of an accumulator according to the invention
• FIG. 7 is another graph obtained in the context of the tests of Example 1 and illustrating the evolution of the discharge capacity C (in mAh) as a function of the number of cycles N of an accumulator according to the invention .
• the same gelling polymer is used, whether for the positive electrode or the negative electrode. It is the polymer comprising repeating units resulting from the polymerization of vinylidene fluoride (96.7% by moles), acrylic acid (0.9% by moles) and hexafluoropropene (2.4% by moles ) and having an intrinsic viscosity of 0.30 L / g in dimethylformamide at 25 ° C.
• This polymer is designated below by the terminology “Polymer 1”.
• This is incorporated into the ink intended for the manufacture of the electrodes in the form of an acetone solution in which 10% of polymer 1 has been dissolved at 60 ° C. This solution is cooled to room temperature and introduced into a glove box under an argon atmosphere (0 2 ⁇ 2 ppm, H 2 0 ⁇ 2 ppm).
• liquid electrolyte composed of a mixture (EC: PC) in mass proportion (1: 1) (EC denoting ethylene carbonate and PC denoting propylene carbonate), vinylene carbonate (up to 2% by mass) and a lithium salt LÎPF 6 (1 M).
• the liquid electrolyte was added so as to obtain a mass ratio (melectrolyte / (melectrolyte + nipolymer 1)) X 100 equal to 85.7%.
• the whole placed in a hermetically sealed bottle in order to avoid the evaporation of acetone was mixed for 1 hour using a magnetic stirrer.
• bipolar current collector coated with electrodes and the two positive and negative terminal electrodes were prepared from the same strip (hereinafter called bipolar electrode strip), so that the bipolar cell is constructed from positive electrodes and negative having strictly the same characteristics.
• the preparation of a bipolar electrode strip by coating was carried out in an anhydrous room (with a dew point of -40 at 20 ° C) using a laboratory coating table.
• an LTO negative electrode strip was produced by coating the ink prepared above on an aluminum foil (having a thickness of 20 mm) over a width of 100 mm by applying a thickness of coating of 320 miti. It was dried in the open air in an anhydrous room for 30 minutes. Its surface capacity was measured at 1.5 mAh / cm 2 .
• Another strip of positive NMC electrode was produced by coating the ink prepared above on the other face of the same aluminum sheet, behind the layer of LTO, preferably in the center, on the same width of 75 mm, applying a coating thickness of 360 mites. It was dried in the open air in an anhydrous room for 30 minutes. Its surface capacity was measured at 1.65 mAh / cm 2 . * Preparation of the basic components for the preparation of the bipolar current collector coated with electrodes and terminal electrodes and
• the three rectangles thus prepared constitute the basic components which were used to develop the bipolar current collector coated with the electrodes and the two negative and positive terminal electrodes of the bipolar accumulator.
• Each rectangle was compressed between two metallic plates of 100mm x 100mm under a mass of 2 tonnes, in order to ensure the same level of densification for all the electrodes.
• the positive terminal electrode is made from one of the three basic components mentioned above.
• the square shaped terminal electrode of dimensions 32mmx32mm is cut leaving a strip of bare aluminum of dimensions 5mmx20mm for the current recovery.
• the negative electrode layer is completely removed, revealing the metal current collector.
• the negative terminal electrode is produced by a procedure similar to the procedure for the positive electrode:
• the bipolar current collector coated with electrodes is produced from the third basic component, by cutting the strip of bare aluminum 24mm wide over a length of 25mm, thus leaving a tab 15mm wide. To this is then welded by ultrasound a thinner (5mm) and longer tongue, which will be used to control the voltage of the electrode. As with the terminal electrodes, a sealing tape will be placed at the level of the heat-sealing area of the packaging.
• a strip of Kapton ® type adhesive is bonded to each side of the 4mm bare aluminum strip, in order to avoid any electrical short circuit between the positive and negative electrodes. and bipolar, once assembled.
• the hybrid polymer membrane consists of an organic / inorganic hybrid copolymer based on modified PVdF-HFP having methacrylic branches (PVdF-HEA-HFP) in which a sol-gel reaction is carried out using tetraethoxysilane (TEOS).
• PVdF-HEA-HFP modified PVdF-HEA-HFP having methacrylic branches
• TEOS tetraethoxysilane
• PVdF - HEA-HFP VDF 96.8% by mole-HEA 0.8% by mole and HFP 2.4% by mole
• HFP hexafluoropropene
• the polymer solution is transferred to a sealed bottle in an anhydrous room (dew point -20 ° C to 22 ° C). It is then coated using an R2R coating machine (“Roll to roll slot die coating machine, Ingecal tailored made”), the solution being introduced into the machine at room temperature but in a controlled environment with a point dew from -20 ° C to 22 ° C.
• R2R coating machine Roll to roll slot die coating machine, Ingecal tailored made
• -Drying section 40 ° C for the first and second zone; 50 ° C for the third zone and 60 ° C for the fourth zone;
• the membrane strip thus obtained is then stored in a sealed heat-sealed pocket while awaiting the assembly of the bipolar accumulator.
• Two membranes of dimensions 34mm x 34mm are cut and deposited on the 2 faces of the bipolar current collector coated with electrodes.
• the terminal electrodes are then placed against the membranes, opposite each electrode of opposite polarity of the bipolar current collector.
• the bipolar electrochemical core with two compartments is then fixed in a flexible packaging consisting of a multilayer sheet of aluminum.
• the assembly is then heat-sealed, the heat-sealing zone necessarily passing through the sealing tapes of the two terminal electrodes and the bipolar current collector coated with the electrodes, in order to ensure the sealing of the packaging with respect to the 'humidity.
• the expected capacity of the battery is 15.3 mAh. This was cycled at room temperature 20 ° C with a current of ⁇ 100 mA enters the potential range [2-6V] and with cut-off voltages per compartment fixed between IV and 3V.
• the test shows that the two compartments operate in exactly the same way with an overlay of the voltage curves at all cycles for the first cell and the second cell, as illustrated in FIG. 5 (illustrating the evolution of voltage U (in V) as a function of time t (in h) with curves a) and b) for the first cell and the second cell of the accumulator and curve c) for the accumulator as such).
• FIG. 6 illustrates the evolution of the discharge capacity C (in mAh) as a function of the number of cycles N.
• FIG. 7 illustrates the evolution of the discharge capacity C (in mAh) in function of the number of cycles N.
• bipolar accumulator similar to that defined above has been produced, except that the active material of the negative electrode has been replaced by graphite and the bipolar current collector has been replaced by a bipolar current collector resulting from the joining of a copper foil and an aluminum foil, the side occupied by the copper foil receiving the negative electrode and the side occupied by the aluminum foil accommodating the positive electrode.
• the performance of this accumulator is very good, in particular, in terms of stable performance during cycling with similar behavior of the compartments (which attests to the absence of ionic leakage).
• an accumulator similar to that defined above has also been produced, except that it does not comprise two cells based on positive electrode NMC and negative electrode LTO but three cells.
• the performance of this accumulator is also very good, in particular, in terms of stable performance during cycling with behavior of similar compartments (which attests to the absence of ionic leakage).

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