METHOD FOR MANUFACTURING AN ASSEMBLY COMPRISING AN ELECTRODE AND A CURRENT COLLECTOR

Abstract

The invention relates to a method for manufacturing an assembly comprising a first flat electrode including a polymer matrix trapping an electrolyte and a current collector, said first electrode being deposited on a face of said current collector, said method comprising: a) a step of preparing a composition including the ingredients intended to be part of the constitution of the first electrode; b) a step of forming a strip by passing said composition through a die; c) a step of rolling the strip obtained in b), d) a step of co-rolling the rolled strip obtained in c) with a current collector, thereby resulting in the assembly comprising the first flat electrode and the current collector.

Description

Title of the invention: METHOD FOR MANUFACTURING AN ASSEMBLY COMPRISING AN ELECTRODE AND A CURRENT COLLECTOR technical field

[0001] The present invention relates to a method for manufacturing an assembly comprising at least one electrode comprising a polymeric matrix trapping an electrolyte and a current collector, this assembly being intended to be incorporated into electrochemical accumulators.

[0002] The general field of the invention can be defined as that of energy storage devices, in particular, that of electrochemical accumulators. Prior art

[0003] 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 an exchange of electrons which gives rise to the electric current and an exchange of ions which will circulate from one electrode to the other by means of an electrolyte.

[0004] Among the batteries subscribing to this principle, batteries operating on the principle of insertion-disinsertion of a metallic element acting at the level of the electrodes (and more specifically, the active materials of the electrodes) and known under the terminology of metal-ion batteries (for example, Li-ion, Na-ion, K-ion, Ca-ion, Mg-ion or Al-ion) have supplanted other types of batteries, such as lead-acid batteries, Ni-MH batteries, in particular for their performance in terms of energy densities. Indeed, M-ion batteries, such as Li-ion batteries, allow, in particular, to obtain mass and volume energy densities (which can be greater than 180 Wh.kg ') significantly higher than those of Ni-MH and Ni-Cd batteries (which can range from 50 and 100 Wh.kg ') and lead-acid batteries (which can range from 30 to 35 Wh.kg ').

[0005] From a functional point of view, in metal-ion batteries, the reaction that generates current (i.e., when the battery is in discharge mode) involves the transfer, via a metal-ion conductive electrolyte, of metal cations from a negative electrode that intercalate into the acceptor network of the positive electrode, while electrons from the reaction at the negative electrode power the external circuit, to which the positive and negative electrodes are connected.

[0006] More specifically, in the case of a Li-ion battery, the positive electrode may include, as lithium insertion materials, lithium-based phosphate compounds (for example, LiFePO4), a lithium manganese oxide, possibly substituted (such as LiMn2O4), a lithium-nickel-manganese-cobalt material LiNixMnyCozO2 with x+y+z=1 (also known by the abbreviation NMC), such as LiNioj33Mnoj33Cooj33O2 or LiNi0,6Mn0,2Co0,2O2, a lithium-nickel-cobalt-aluminium material LiNixCoyAlzO2 with x+y+z = 1 (also known by the abbreviation NCA), such as LiNio>8Cooji5Alojo5O2.

[0007] The negative electrode may include, as lithium insertion materials, a carbonaceous material, such as graphite, a silicon-based compound, such as silicon carbide SiC or silicon oxide SiOx, a lithium titanium oxide, such as Li4Ti5O i2, a lithium-germanium alloy or a mixture of several of these lithium insertion materials, such as a mixture comprising graphite and a silicon-based compound.

[0008] As mentioned above, between the negative electrode and the positive electrode, an electrolyte is placed, which will allow the movement of ions (generally from a metallic salt present in the electrolyte) from the positive electrode to the negative electrode during charging and vice versa during discharging.

[0009] This electrolyte can be in liquid form and classically comprises one or more organic solvents (for example, a mixture of carbonate solvents), in which one or more metallic salts are dissolved (for example, one or more lithium salts, when the accumulator is a lithium-ion accumulator).

[0010] However, the use of a liquid electrolyte presents a number of disadvantages, including the following: - the problem of liquid electrolyte leaking out of the cell; - the possibility that the liquid electrolyte may react chemically with the oxygen in the active material of the positive electrode when thermal runaway occurs in the cell containing this electrolyte, potentially generating a significant volume of gas, which could lead to ignition or even explosion of the cell.

[0011] To overcome these drawbacks, an alternative is to eliminate the use of a liquid electrolyte by replacing it, for example, with the following solutions: - a lithium ion-conducting glass or ceramic in a purely solid form, for example, a thin film deposited by chemical vapor deposition (CVD) such as a LIPON layer, or a layer of a composite material comprising a polymeric matrix, for example, in poly(vinylidene fluoride), and a filler consisting of a lithiated oxide, such as Li7La3Zr20i2; - a dry polymer solid electrolyte composed of a poly(ethylene oxide) (POE) type polymer and a lithium salt, for example, lithium Z?z'5(trifluorosulfonyl)imidide (LiTFSI).

[0012] However, these different solutions all currently present a number of disadvantages.

[0013] Regarding the use of glass or ceramics that conduct lithium ions, this requires very complex implementation or synthesis techniques to be developed in an industrial context, which may prove prohibitive for the large-scale production of batteries.

[0014] Regarding dry polymer solid electrolytes, their ionic conductivity at room temperature is generally less than 10⁵ S·cm⁻¹, whereas for a conventional liquid electrolyte, the ionic conductivity is on the order of 10³ S·cm⁻¹, or even 10² S·cm⁻¹ at room temperature. Therefore, it may be necessary to use batteries containing a dry polymer electrolyte at temperatures higher than room temperature, for example, a temperature ranging from 60 to 80°C, to promote the diffusion of lithium ions within the electrolyte.

[0015] To overcome the disadvantages associated with the use of a liquid electrolyte and those of the aforementioned solid electrolytes, a new technology developed and illustrated in WO2015169835 consists of trapping the liquid electrolyte in a polymeric matrix that is an integral part of the positive and negative electrodes (these electrodes can be described as ionogel electrodes), this technology making it possible to obtain at room temperature electrochemical performance equivalent to that of a lithium-ion battery comprising a liquid electrolyte not trapped in a polymeric matrix.

[0016] These electrodes are prepared in a conventional manner by a process comprising successively the following steps: - a step of manufacturing an ink (i.e. a liquid dispersion comprising in suspension the solid ingredients of the electrode) by mixing the different ingredients intended to be part of the constitution of the electrode, namely, the active material, the electronic conductive additive(s), a fluorinated (co)polymer which allows the trapping of the liquid electrolyte, at least one solvent of this fluorinated copolymer (for example, acetone), a lithium salt, one or more electrolyte solvents (such as carbonate solvents) to solubilize the lithium salt; - once the ink is obtained, a step of depositing it, generally by coating onto a support forming the current collector; -an evaporation step of the solvent(s) of the fluorinated (co)polymer possibly followed by a calendering step whereby the specific electrode remains.

[0017] The ink manufacturing step, which generally takes place in mixers Traditional methods, such as a disperser or planetary mixer, require a significant proportion of solvent(s), which limits the percentage of solid mass in the ink. More specifically, the percentage of solid mass relative to the total mass of the ink is generally between 35 and 49% by mass, while the mass of the liquid electrolyte (salt + electrolyte solvent(s)) is between 6 and 13% of the total mass of the ink, and the solvent(s) of the fluorinated (co)polymer are between 45 and 57% of the total mass of the ink.

[0018] The presence of such a quantity of solvent(s) constitutes a limiting factor for the implementation of such a process, particularly at the industrial level, because it implies the implementation of effluent management (here, the solvent used in large quantities) both in terms of safety (in particular, due to the potential flammability of the chosen solvent(s) and / or the toxicity of the chosen solvent(s)) and of the disposal of the solvent(s), which also generates significant implementation costs for this process.

[0019] In this context, the inventors have therefore set themselves the objective of proposing a new manufacturing process for an assembly comprising an electrode including a polymeric matrix containing an electrolyte and a current collector, which makes it possible to reduce or even eliminate the use of solvent(s) and which is, in fact, less expensive and limits the disadvantages related to the use of solvent(s).Furthermore, the inventors have also set themselves the objective of developing a manufacturing process for an assembly as defined above, which no longer involves the prior preparation of an ink but rather the prior preparation of a composition in the form of a paste comprising the ingredients intended to be used in the constitution of the electrode, this preparation being made possible by the use of a specific mixer during this stage and whose shaping and association with a current collector stages are carried out in such a way as to avoid fouling of the elements used for the implementation of said stages. Description of the invention

[0020] To this end, the inventors have developed a method for manufacturing an assembly comprising a first flat electrode comprising a polymer matrix trapping an electrolyte and a current collector, said first electrode being deposited on one face of said current collector, said method comprising the following steps: (a) a step of preparing a composition comprising the ingredients intended to form part of the first electrode, said step consisting of introducing and mixing the ingredients intended to form part of the electrode in a mixer with two co-rotating interpenetrating screws rotating in a closed sheath, at a temperature below 100°C; b) from the composition obtained in a), a step of forming a strip by passing said composition through a die; c) a step of rolling the strip obtained in b), by passing it between a first roller, called the upper roller, and a second roller, called the lower roller, a first polymer sheet being interposed between the first roller and the strip and a second polymer sheet being interposed between the second roller and the strip (in order to avoid any direct contact between the rollers and the strip), the first polymer sheet being dissociated from the strip at the end of the rolling step while the second polymer sheet remains attached to the strip thus rolled at the end of the rolling step, whereby a rolled strip is produced coated on one face, called the lower face, by the second polymer sheet and whose face opposite the lower face, called the upper face, is free (i.e. uncoated); d) a co-lamination step of the laminated strip obtained in c) with a current collector by passing it between a first roller, called the upper roller, and a second roller, called the lower roller, the lower face of the strip being in contact with the second roller via the second polymeric sheet and the upper face being in contact with the first roller via the current collector interposed between the first roller and the upper face, the second polymeric sheet being possibly dissociated from the strip at the end of the co-lamination step while the current collector remains attached to the upper face of the strip thus co-laminated at the end of the co-lamination step, thereby resulting in the assembly comprising the first flat electrode and the current collector.

[0021] Thanks to this sequence of steps preserving in particular any contact between the rollers and the strip coming from the die, it is possible to avoid any damage to the latter by said rollers and also the fouling of the latter, which makes it possible to consider a continuous implementation of said process.

[0022] Initially, as mentioned above, the process of the invention includes a step of preparing a composition comprising the ingredients intended to be part of the electrode, said step consisting of introducing and mixing the ingredients intended to be part of the electrode in a mixer with two co-rotating interpenetrating screws rotating in a closed sleeve, at a temperature below 100°C.

[0023] The introduction of the ingredients may be simultaneous or successive, and this introduction may be carried out at separate locations (for example, the introduction of the solid constituents into a first introduction zone via one or more inlets of the mixer and the introduction of the liquid constituents into a second introduction zone via one or more inlets of the mixer), as may be the case with the mixer illustrated in the attached [Fig.1], which includes: - a closed sheath 1; - two interpenetrating screws 3 and 5; - a first introduction zone 7 (called zone A) of the ingredients; - a second introduction zone 9 (called zone B) for ingredients; and - an outlet 11 for the evacuation of the formed composition; - a motor 13 connected to the screws to generate their rotation.

[0024] Thanks to the use of this specific mixer, it is possible to eliminate the presence of solvent(s) other than the solvent(s) present in the electrolyte, compared to a process using conventional mixers and therefore to limit the disadvantages related to effluent management.

[0025] More specifically, this composition may include, as constituent ingredients of the electrode: -at least one active electrode material; -at least one polymer intended to be part of the composition of the polymer matrix; -an electrolyte; -possibly at least one electronic conductive additive.

[0026] The active electrode material is a material capable of inserting and removing, in its structure, metallic ions, such as alkali ions (for example, lithium ions, when the accumulator is a lithium accumulator, sodium ions, when the accumulator is a sodium accumulator, or potassium ions, when the accumulator is a potassium accumulator), alkaline earth ions (for example, magnesium ions, when the accumulator is a magnesium accumulator, calcium ions, when the accumulator is a calcium accumulator), metallic ions (for example, aluminium ions, when the accumulator is an aluminium-ion accumulator).

[0027] The nature of the active material depends of course on its intended use, namely whether it is intended for a positive electrode or a negative electrode.

[0028] Also, when the process of the invention is intended for the manufacture of a positive electrode, by way of examples of active electrode materials that could be used in the constitution of a positive electrode of a lithium battery, mention may be made of: - metallic chalcogenides of formula LiMQ2, in which M is at least one metallic element chosen from among the metallic elements, such as Co, Ni, Fe, Mn, Cr, V, Al and Q is a chalcogen, such as O or S, the preferred metallic chalcogenides being those of formula LiMO2, with M being as defined above, such that, in a preferred, LiCoO2, LiNiO2, LiNixCoi x02 (with 0 <x<l), un matériau à base de lithium-nickel-manganèse-cobalt LiNixMnyCozO2 avec x+y+z=l (connu également sous l’abréviation NMC), tel que LiNioj33Mnoj33Cooj3302j ou un matériau à base de lithium-nickel-cobalt-aluminium LiNixCoyAlzO2 avec x+y+z=l (connu également sous l’abréviation NCA), tel que LiNio> 8Cooji5Alojo502; - chalcogenides with spinel structure, such as LiMn2O4; - lithia-coated or partially lithia-coated materials of formula MiM2(JO4)fEi_f, in which Mi is lithium, which may be partially substituted by another alkali 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 additional metallic elements of oxidation state(s) between +1 and +5 up to a substitution rate of less than 35%, JO4 is an oxyanion in which J is chosen from P, S, V, Si, Nb, Mo and combinations thereof, E is a fluoride, hydroxide or chloride anion, f is the mole fraction of the JO4 oxyanion and is generally between 0.75 and 1 (including 0.75 and 1).

[0029] More specifically, the lithia-coated or partially lithia-coated materials may be phosphorus-based (meaning, in other words, that the oxyanion corresponds to the formula PO4) and may exhibit an ordered or modified olivine-type structure.

[0030] Lithified or partially lithified materials may conform to the specific formula Li3 xM'yM”2 y(JO4)3, in which 0 <x<3, 0<y<2, M’ et M” représentent des éléments métalliques identiques ou différents, l’un au moins des M’ et M” étant un élément métallique de transition, JO4 est, de préférence, PO4, qui peut être partiellement substitué par un autre oxyanion avec J étant choisi parmi S, V, Si, Nb, Mo et les combinaisons de ceux-ci.

[0031] Lithified or partially lithified materials may conform to the formula Li(FexMni x)PO4, in which 0 <x<l et, de préférence, x est égal à 1 (ce qui signifie, en d’autres termes, que le matériau correspondant est LiFePO4).

[0032] When the process of the invention is intended for the manufacture of a negative electrode, by way of examples of active electrode materials that could be used in the constitution of a negative electrode of a lithium battery, mention may be made of: - carbon materials, such as graphitic carbon suitable for intercalating lithium, which typically exists in the form of a powder, flakes, fibers or spheres (for example, mesocarbon microbeads); - silicon-based compounds, such as silicon carbide SiC or silicon oxide SiOx; - metallic lithium; - lithium alloys, such as those described in US 6203944 and / or WO 00 / 03444; - Lithified titanium oxides, such as an oxide with the formula Li(4x)MxTi5Oi2 or Li4MyTi(5y)Oi2, where x and y range from 0 to 0.2, and 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 Li4Ti5O12, these oxides being lithium insertion materials exhibiting a low level of physical expansion after lithium insertion; - non-lithianed titanium oxides, such as TiO2; - oxides of formula MyTi(5_y)Oi2 in which y goes from 0 to 0.2 and M is an element chosen from Na, K, Mg, Nb, Al, Ni, Co, Zr, Cr, Mn, Fe, Cu, Zn, Si and Mo; - lithium-germanium alloys, such as those comprising crystalline phases of the formula Li44Ge; or - a mixture of these, such as a mixture comprising graphite and a silicon-based compound.

[0033] The polymer(s) suitable for inclusion in the constitution of the polymeric matrix are advantageously chosen from among gelling polymers capable of gelling on contact with the electrolyte and thus trapping the electrolyte (the resulting electrode thus forming an electrode commonly called an "ionogel electrode") and, more specifically, can be chosen from among 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, possibly in the form of a salt.

[0034] It is understood that the repeating unit(s) resulting from the polymerization of a fluorinated monomer and, where applicable, the repeating unit(s) resulting from the polymerization of a monomer comprising at least one carboxylic acid group, possibly in the form of a salt, are chemically different repeating units and, in particular, the repeating unit(s) resulting from the polymerization of a fluorinated monomer do not comprise any carboxylic acid group(s), possibly in the form of a salt.

[0035] For gelling polymers, the repeating unit(s) 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 fluorine atom and optionally one or more other halogen atoms. Examples of monomers of this type are as follows: - C2-C8 perfluoroolefins, such as tetrafluoroethylene, hexafluoropropene (also known by the abbreviation HFP); - C2-C8 hydrogenated fluoroolefins, such as vinylidene fluoride, vinyl fluoride, 1,2-difluoroethylene and trifluoroethylene; - perfluoroalkylethylenes of formula CH2=CHR1, in which R1 is a group perfluoroalkyl in Ci-C6; - C2-C6 fluoroolefins containing one or more other halogen atoms (such as chlorine, bromine, iodine), such as chlorotrifluoroethylene; - (per)fluoroalkylvinyl ethers of formula CF2=CFOR2, in which R2 is a fluoro- or perfluoroalkyl group in Ci-C6, such as CF3, C2F5, C3F7; - monomers of formula CF2=CFOR3, in which R3 is a CrCi2 alkyl group, a CrCi2 alkoxy group, or a CrCi2 (per)fluoroalkoxy group, such as a perfluoro-2-propoxypropyl group; and / or - monomers of the formula CF2=CFOCF2OR4, in which R4 is a fluoro- or perfluoroalkyl group in C1-C6, such as CF2, C2F5, C3F7 or a fluoro- or perfluoroalkyl group in C1-C6, such as -C2F5-O-CF3

[0036] More particularly, the gelling polymer(s) may include, 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 of C2-C8 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.

[0037] The repeating unit(s) resulting from the polymerization of a monomer comprising at least one carboxylic acid group, possibly in the form of a salt, may be, more specifically, one or more repeating units resulting from the polymerization of a monomer of the following formula (I): [Chem. 1] (0 in which R5 to R7 represent, independently of each other, a hydrogen atom or an alkyl group in CrC3 and R8 represents a hydrogen atom, a monovalent cation (for example, an alkali cation, an ammonium cation) or a hydrocarbon group, saturated or unsaturated, in Ci-C5 comprising at least one carboxylic acid group, particular examples of monomers of this type being acrylic acid, methacrylic acid or 2-carboxyethyl acrylate.

[0038] Particular gelling polymers usable within the scope of the invention may be polymers comprising a repeating unit resulting 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 even actually a repeating unit resulting from the polymerization of a fluorinated monomer other than vinylidene fluoride (and more specifically, a repeating unit resulting from the polymerization of hexafluoropropene).

[0039] More specifically, gelling polymers usable within the framework of the invention are gelling polymers, the aforementioned repeating units of which are obtained from polymerization: - of at least 70% by moles of a C2-C8 hydrogenated fluoroolefin, preferably vinylidene fluoride; - 0.1 to 15% by moles of a C2-C8 perfluoroolefin, preferably hexafluoropropene; and - from 0.01 to 20% by moles of a monomer of formula (I) above, preferably acrylic acid.

[0040] Moreover, the gelling polymer(s) advantageously exhibit an intrinsic viscosity measured at 25°C in N,N-dimethylformamide ranging from 0.1 to 1.0 L / g, preferably from 0.25 to 0.45 L / g.

[0041] More specifically, the intrinsic viscosity is determined by the equation below based on the falling time, 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:

[0042] [Math.l] r -] _ x 111%) “(i+r)xc in which: - q corresponds to the intrinsic viscosity (in dL / g); - c corresponds to the polymer concentration (in g / dL); - qr corresponds to the relative viscosity, that is to say the ratio between the time it takes for the solution to fall and the time it takes for the solvent to fall; - qsp corresponds to the specific viscosity, i.e. pr - 1; - T corresponds to an experimental factor set at 3 for the polymer in question.

[0043] The electrolyte is advantageously a liquid electrolyte and, more specifically, a liquid electrolyte which can gel upon contact with the polymeric matrix, when the latter comprises one or more gelling polymers.

[0044] The liquid electrolyte may comprise (or even be made up of) at least one organic solvent, at least one metallic salt and possibly an additive belonging to the category of carbonate compounds (it being understood that this additive is different from the carbonate solvent(s) included, if any, in the electrolyte).

[0045] The organic solvent(s) may 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 thereof.

[0046] The organic solvent(s) may 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).

[0047] The organic solvent(s) may also be ionic liquids, that is to say, classically, 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.

[0048] More specifically, ionic liquids may include: - a cation chosen from among the cations imidazolium, pyridinium, pyrrolidinium, piperidinium, quaternary ammonium, quaternary phosphonium, pyrazolium, said cations being possibly substituted, for example, by at least one alkyl group comprising from 1 to 30 carbon atoms; - an anion chosen from among halide anions, perfluorinated anions, and borates.

[0049] More specifically, the cation can be chosen from among the following cations: - a pyrrolidinium cation of the following formula (II): in which R13 and R14 represent, independently of each other, an alkyl group in CrC8 and R15, R16, R17 and R18 represent, independently of each other, a hydrogen atom or an alkyl group in Ci-C30, preferably, an alkyl group in C1-C18, preferably again, an alkyl group in CrC8; - a piperidinium cation of the following formula (III): [Chem. 3]

[0050] R1S r20 R23 (III) in which R19 and R20 represent, independently of each other, an alkyl group in CrC8 and R21, R22, R23, R24 and R25 represent, independently of each other, a hydrogen atom or an alkyl group in Ci-C30, preferably, an alkyl group in C1-C18, preferably again, an alkyl group in CrC8; - a quaternary ammonium cation; - a quaternary phosphonium cation; - an imidazolium cation; and - a pyrazolium cation. In particular, the positively charged cation can be chosen from the following cations: - a pyrrolidinium cation with the following formula (II-A): [Chem. 4] (II-A) - a piperidinium cation with the following formula (III-A): (1II-A)

[0051] When dealing with a quaternary ammonium cation, it can correspond to a tetraalkylammonium cation, a trialkylarylammonium cation, or a tetraarylammonium cation; the alkyl groups, when present, may be identical or different. and which may correspond to alkyl groups, linear or branched, comprising from 4 to 12 carbon atoms, preferably from 4 to 6 carbon atoms, and the aryl groups, when present, being identical or different and which may correspond to a phenyl group, a benzyl group or a naphthyl group. More specifically, it may be a tetraethylammonium cation, a tetrapropylammonium cation, a tetrabutylammonium cation, a trimethylbenzylammonium cation, a methyltributylammonium cation, an N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium cation, an N,N-dimethyl-N-ethyl-N-(3-methoxypropyl)ammonium cation, an N,N-dimethyl-N-ethyl-N-benzylammonium cation, an N,N-dimethyl-N-ethyl-N-phenylethyl-ammonium cation, an N-tributyl-N-methylammonium cation, an N-trimethyl-N-butylammonium cation, an N-trimethyl-N-hexylammonium cation, an N-trimethyl-N-propylammonium cation.

[0052] When dealing with a quaternary phosphonium cation, it may correspond to a tetraalkylphosphonium cation, a trialkylarylphosphonium cation, or a tetra-arylammonium cation. The alkyl groups, when present, may be identical or different and may correspond to linear or branched alkyl groups comprising from 4 to 12 carbon atoms, preferably from 4 to 6 carbon atoms. The aryl groups, when present, may be identical or different and may correspond to a phenyl group, a benzyl group, or a naphthyl group. More specifically, it may be a trihexyl(tetradecyl)phosphonium cation or a tetrabutylphosphonium cation.

[0053] When it is an imidazolium cation, it can correspond to a 1,3-dimethylimidazolium cation, an l-(4-sulfobutyl)-3-methylimidazolium cation, an l-allyl-3H-imidazolium cation, an l-butyl-3-methylimidazolium cation, an l-ethyl-3-methylimidazolium cation, an l-hexyl-3-methylimidazolium cation, an l-octyl-3-methylimidazolium cation.

[0054] Specifically, the negatively charged anion can be chosen from: - 4,5-dicyano-2-(trifluoromethyl)imidazole (known by the abbreviation TDI); - the Z?zXfluorosulfonyl)imidide (known by the abbreviation FSI); - the Z?zXtrifluoromethylsulfonyl)imidide of formula (SO2CF3)2N; - hexafluorophosphate of formula PF6; - tetrafluoroborate with the formula BF4; - oxaloborate of the following formula (IV): [Chem. 6] (IV)

[0055] A specific and usable ionic liquid according to the invention may be an ionic liquid composed of a cation of formula (II-A) as defined above and an anion of formula (SO2CF3)2N, PF6 or BF4.

[0056] The metal salt(s) may be chosen from the following salts with the following formulas: Mel, Me(PF6)n, Me(BF4)n, Me(ClO4)n, Me(bis(oxalato)borate)n (which may be abbreviated as Me(BOB)n), MeCF3SO3, Me[N(FSO2)2]n, Me[N(CF3SO2)2]n, Me[N(C2F5SO2)2]n, Me[N(CF3SO2)(RFSO2)]n, where RF is a -C2F5, -C4F9 or -CF3OCF2CF3 group, Me(AsF6)n, Me[C(CF3SO2)3]n, Me2Sn, Me(C6F3N4) (C6F3N4 corresponds to 4,5-dicyano-2-(trifluoromethyl)imidazole and, when Me is Li, the salt corresponds to of lithium 4,5-dicyano-2-(trifluoromethyl)imidazole, this salt being known by the abbreviation LiTDI), wherein Me is a metallic element and, preferably, a transition metal element, an alkali element or an alkaline earth element and, even more preferably, Me is Li (in particular, when the accumulator of the invention is a lithium-ion or lithium-air accumulator), Na (in particular, when the accumulator is a sodium-ion accumulator), K (in particular,(when the battery is a potassium-ion battery), Mg (in particular, when the battery is a Mg-ion battery), Ca (in particular, when the battery is a calcium-ion battery) and Al (in particular, when the battery is an aluminium-ion battery) and n corresponds to the degree of valence of the metallic element (typically, 1, 2 or 3).

[0057] When Me is Li, the salt is, preferably, LiPF6.

[0058] The concentration of the metallic salt in the liquid electrolyte is advantageously at least 0.01 M, preferably at least 0.025 M and, even more preferably, at least 0.05 M and, advantageously, at most 5 M, preferably at most 2 M and, even more preferably, at most 1 M.

[0059] In addition, the liquid electrolyte may include at least one additive belonging to the category of carbonate compounds (it being understood that this additive is different from the carbonate solvent(s) included, if any, in the electrolyte), such as vinylene carbonate or fluoroethylene carbonate, this additive being included in the electrolyte at a content not exceeding 5% by mass of the total mass of the electrolyte.

[0060] A liquid electrolyte that can be used, particularly when the electrode manufactured according to the process of the invention is intended for a lithium-ion battery, is a electrolyte comprising a mixture of carbonate solvents (for example, a mixture of cyclic carbonate solvents, such as a mixture of ethylene carbonate and propylene carbonate or a mixture of cyclic carbonate solvents and linear carbonate solvent(s), such as a mixture of ethylene carbonate, propylene carbonate and dimethyl carbonate), a lithium salt, for example, LiPF6 (for example, IM) and optionally an additive, such as vinylene carbonate, fluoroethylene carbonate.

[0061] As mentioned above, the composition may contain at least one electronically conductive additive, that is to say an additive capable of giving the electrode, in which it is incorporated, electronic conductivity, this additive being able to be, for example, chosen from carbon materials such as carbon black, carbon nanotubes, carbon fibers (in particular, vapor-phase carbon fibers known by the abbreviation VGCF), graphite in powder form, graphite fibers, graphene and mixtures thereof.

[0062] Furthermore, the composition may include at least one solvent (other than, where applicable, any organic solvent(s) of the electrolyte) for the polymer(s) intended to form part of the polymer matrix. This solvent may be a ketone solvent (such as acetone), provided that the polymer(s) are selected from the family of 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, possibly in the form of a salt. Thanks to the use of the specific mixer, this solvent(s) may be used in smaller quantities compared to a process involving the use of a traditional mixer.

[0063] In the case where the composition includes at least one solvent as mentioned above, the process advantageously includes, after the preparation step, an evaporation step, for example, selective, of the solvent or solvents of the polymer or polymers intended to be included in the constitution of the polymeric matrix, for example, by in-line drying by selective evaporation.

[0064] The preparation step is carried out at a temperature below 100°C, preferably at a temperature below 80°C and, even more preferably, at a temperature below 70°C and, preferably, at a temperature greater than or equal to 5°C, more preferably, greater than or equal to 10°C, and even more preferably, greater than or equal to 15°C.

[0065] More specifically, the preparation step can be carried out at ambient temperature (i.e., the temperature of the environment in which the preparation step takes place, without the input of heat from any heating element, for example, a temperature ranging from 15 to 35°C, and more specifically, a temperature equal to 25°C) or may be carried out at a temperature above ambient temperature, for example, a temperature above ambient temperature but below 100°C. More specifically, the preparation step may be carried out at a temperature above ambient temperature but below the boiling point of the solvent(s) of the polymer(s) intended to be part of the polymer matrix, when this solvent(s) are present in the composition or when this solvent(s) are not present, at a temperature above ambient temperature but below the melting point of the polymer(s) intended to be part of the polymer matrix (it being understood that the temperature at which the preparation step is carried out is always below 100°C).

[0066] The preparation step makes it possible to obtain a composition in the form of a homogeneous paste and exhibiting a very high dynamic viscosity, and more specifically, a dynamic viscosity greater than 5,000 Pa.s, preferably greater than 6,000 Pa.s and, preferably even greater than 7,000 Pa.s, measured at a shear gradient of 0.1 s 1 and at room temperature.

[0067] It is specified that, by ambient temperature, it is understood to mean the temperature of the environment, in which the dynamic viscosity measurement takes place, without heat input by any heating element, for example, a temperature ranging from 15 to 35°C, such as, for example, a temperature equal to 25°C.

[0068] More specifically, the dynamic viscosity of the composition is measured using a Malvem Bohlin CVO rheometer equipped with a Peltier support and a 40 mm diameter cone-plane moving part with a 4° angle. The composition is deposited between the Peltier support and the moving part at an air gap of 150 µm. If necessary, when the composition includes at least one solvent of the polymer(s) constituting the polymer matrix, a solvent trap is added to the system to prevent excessively rapid evaporation of the solvent(s). The measurement is performed in viscosimilar mode at a shear rate of 0.1 s⁻¹ and at room temperature with an integration time of 5 seconds.

[0069] Furthermore, the composition in paste form generally exhibits a dynamic viscosity not exceeding 20,000 Pa·s, preferably not exceeding 18,000 Pa·s, under the conditions defined above (namely, at a shear rate of 0.1 s⁻¹ and at room temperature). Very advantageous results have been obtained when the composition is in paste form with a dynamic viscosity ranging from 7,000 to 12,000 Pa·s under the conditions defined above (namely, at a shear rate of 0.1 s⁻¹ and at room temperature).

[0070] A particularly advantageous aspect of this preparation step lies, in fact, Its ability to prepare an electrode-forming composition with a very high dynamic viscosity minimizes the use of liquid electrolyte and / or organic solvents. This is an advantage over well-established techniques for manufacturing electrodes from inks produced using traditional disperser or planetary mixers, which exhibit a dynamic viscosity of less than 5,000 Pa·s, or even less than 1,000 Pa·s as measured under the conditions mentioned above.

[0071] When the compositions include at least one solvent of the polymer(s) intended to be part of the polymer matrix, these compositions may, after the preparation step, comprise 50 to 80% solid mass relative to the total mass of the composition.

[0072] More specifically, when the compositions comprise, as constituent ingredients, at least one active electrode material, at least one polymer intended to form part of the polymer matrix, an electrolyte, and optionally at least one electronically conductive additive and at least one solvent for the polymer(s), the compositions obtained at the end of this preparation step advantageously have a solid mass percentage relative to the total mass of the composition ranging from 50 to 80% (compared to 35 to 49% with processes involving traditional mixers). Furthermore, these compositions may comprise an electrolyte mass of 6 to 11% of the total mass of the composition and a polymer solvent(s) mass of 11 to 42% of the total mass of the composition (compared to 45 to 57% with processes involving traditional mixers).

[0073] According to a particular and advantageous embodiment, the composition may be solvent-free of the polymer(s) intended to form part of the polymer matrix. Under these conditions, the compositions may comprise, after the preparation step, 83 to 90% solid mass relative to the total mass of the composition.

[0074] The compositions may comprise, at the end of the preparation step, from 83 to 90% solid mass relative to the total mass of the composition.

[0075] More specifically, when the compositions include, as constituent ingredients, at least one active electrode material, at least one polymer intended to be part of the polymer matrix, an electrolyte and possibly at least one electronically conductive additive but are devoid of solvent(s) of the polymer(s), the percentage of solid mass can represent from 83 to 90% of the total mass of the composition and the mass of electrolyte can represent from 10 to 17% of the total mass of the composition.

[0076] Under these conditions, the solvent evaporation step mentioned above is not necessary.

[0077] The preparation step can be carried out continuously, i.e. the introduction of the ingredients and the mixing of them in the specific mixer is carried out continuously, i.e. throughout the entire duration of its implementation of the process.

[0078] After the composition has been prepared, it is subjected, at the outlet of the mixer, to a strip formation step by passing said composition through a die, such as a flat or cylindrical die (for example, with a circular or oblong cross-section). Preferably, the die is a flat die, that is to say, a die whose final cross-section is rectangular, this cross-section advantageously having a height (which will give the thickness of the strip at the outlet of the die) ranging from 100 µm to 2,000 µm, preferably ranging from 300 µm to 1,500 µm and, even more preferably, ranging from 500 µm to 1,000 µm.The section has a width, which will be a function of the desired band width and therefore of the final width of the electrode, taking into account the spreading of the band not only over the length but also over the width, inducing an increase in the band width, which can be by a factor of 2, 3 or even 4 depending on the initial thickness of the band from step b).

[0079] The die is advantageously directly connected to the outlet of the mixer.

[0080] By way of example, [Fig.2] schematically illustrates this band formation step by passing the composition obtained at the end of step a) through a die, the elements illustrated in this figure being the following: - end 15 of the mixer through which the composition thus formed exits; - a flat die 17, into which the composition from the mixer is introduced; - a strip 19 resulting from the shaping of the composition within the die 17.

[0081] The strip thus formed is then subjected to a rolling step, or in other words, a step of reducing its thickness by passing it between a first roller, called the upper roller, and a second roller, called the lower roller, a first polymer sheet being interposed between the first roller and the strip and a second polymer sheet being interposed between the second roller and the strip (in order to avoid any direct contact between the rollers and the strip), the first polymer sheet being dissociated from the strip at the end of the rolling step while the second polymer sheet remains attached to the strip thus rolled at the end of the rolling step, thereby resulting in a rolled strip coated on one face, called the lower face, by the second polymer sheet and whose face opposite the lower face, called the upper face, is a free face, that is to say a face not coated by any element.

[0082] This step is illustrated schematically in [Fig. 3], comprising the elements following: - band 19 from the previously described process; - the upper roller 21; - the first polymeric sheet 23 arranged between the band 19 and the upper roller 21; - the lower roller 25; - the second polymer sheet 27 arranged between the band 19 and the lower roller 25; It is understood that, as indicated by the arrow on the upper roller showing the direction of rotation of said roller and by the arrow on the lower roller showing the direction of rotation of said roller, said upper and lower rollers have opposite directions of rotation to induce a movement of the strip from right to left, as well as of the polymer sheets. In other words, the upper roller has a clockwise direction of rotation, while the lower roller has a counterclockwise direction of rotation. At the end of the rolling step, the strip has a free upper face 29 and a lower face 31 coated by the second polymer sheet. In the preceding and following sections, it should be noted that the same numerical references will be used, provided they designate the same elements in an identical or similar context.

[0083] The upper roller and the lower roller may belong to a rolling mill type device or a calender type device conventionally used to densify electrodes in a conventional lithium-ion battery manufacturing process.

[0084] The first polymeric sheet and the second polymeric sheet can be polyester sheets and, more specifically, poly(ethylene terephthalate) or poly(ethylene naphthalate) sheets, preferably poly(ethylene terephthalate).

[0085] Advantageously, the first polymeric sheet and the second polymeric sheet can be of the same nature.

[0086] Advantageously, the first polymer sheet and / or the second polymer sheet has at least one rough face, in particular, the face intended to be in contact with the strip. More specifically, the first polymer sheet and / or the second polymer sheet may have an average surface roughness, called Ra, ranging from 0.01 pm to 1 pm, preferably even more, ranging from 0.3 pm to 0.7 pm, these values ​​being particularly suitable when the associated electrode is a negative electrode and, even more particularly, when the associated electrode is a negative electrode comprising graphite as the active material.

[0087] The average surface roughness Ra, which can also be called roughness arithmetic mean, designates the average roughness of the surface for the length of the measurement carried out, that is to say the average difference between the peaks and the hollows, whereby the greater the roughness of the surface concerned, the greater the difference between the peaks and the hollows of the latter will be.

[0088] The average surface roughness Ra is determined, conventionally, using a contact profilometer, for example, a Dektak 150 profilometer with a 12.5 pm radius tip from the Bruker brand.

[0089] Furthermore, the first polymeric sheet and / or the second polymeric sheet advantageously has a thickness ranging from 6 pm to 75 pm, preferably from 10 pm to 30 pm.

[0090] As examples of sheets meeting the aforementioned roughness and thickness criteria, mention may be made of the poly(ethylene terephthalate) sheets supplied by Mitsubishi Polyester Film GmbH under the references PET HOSTAPHAN™ MK, these sheets having a thickness of 12 pm, 19 pm or 23 pm and a roughness Ra of 0.3 pm and PET HOSTAPHAN™ XMTK, these sheets having a thickness of 50 pm and a roughness Ra of 0.68 pm.

[0091] In particular, to achieve the required level of roughness, the first polymer sheet and / or the second polymer sheet may be a multi-layer sheet comprising a central polyester layer and, on at least one face of the central layer, a layer comprising a polymer matrix, for example, a polyester polymer matrix trapping inorganic particles, such as silica particles. Sheets of this type are those mentioned above under the reference PET HOSTAPHAN™ MK.

[0092] Moreover, the first polymeric sheet and / or the second polymeric sheet advantageously has a surface energy of less than 40 mN / m, this surface energy characteristic being particularly suitable when the associated electrode is a negative electrode and, even more particularly, when the associated electrode is a negative electrode comprising graphite as the active material.

[0093] The surface energy can be determined—as known per se—by measuring the contact angle of a drop of liquid deposited on the polymer sheet according to the Owens-Wendt method. For example, it can be measured using a tensiometer, such as a tensiometer marketed by KRUSS under the reference DSA100™. In particular, three liquids of different polarities and known polar and dispersive components, namely water, diiodomethane, and glycerol, can be used for this measurement.

[0094] More specifically, when the electrode is a negative electrode comprising graphite as the active material, the first polymeric sheet and / or the second polymeric sheet advantageously exhibits a surface energy lower than the surface energy of the negative electrode, the latter having a surface energy lower than the current collector associated with the electrode.

[0095] The rolling step can be carried out hot and, more specifically, at a temperature ranging from 60°C to 120°C, preferably even more so, ranging from 80°C to 110°C, this temperature being able to be reached by heating the lower roller and the upper roller.

[0096] Whether for the first polymer sheet and the second polymer sheet, these can be supplied by a distributor roller located upstream of the upper roller for the first polymer sheet and a distributor roller located upstream of the lower roller for the second polymer sheet.

[0097] At the end of this step and, where applicable, once the strip has cooled, the first polymer sheet is dissociated from the strip, i.e., it does not remain attached to it, this dissociation being carried out advantageously via a drive roller (reference 33 on [Fig.4] similar to [Fig.3] except for the presence of this drive roller) located downstream of the upper roller, preferably at a predetermined distance, and positioned on the first polymer sheet and the strip and via a winding roller located downstream of the upper roller and the drive roller and in a raised position relative to them and connected to one end of the first polymer sheet, the rotation of the winding roller causing the polymer sheet to move towards the drive roller and then winding around the winding roller.More specifically, the drive roller is positioned at a predetermined distance determined by the time required to cool the web before the first polymer sheet is removed, thus preventing it from sticking to the roller. For example, at a lamination temperature of 80°C and a line speed of 1 m / min, the predetermined distance should be greater than 20 cm.

[0098] After the rolling step, the process includes a co-rolling step of the rolled strip obtained in c) with a current collector by passing it between a first roller, called the upper roller, and a second roller, called the lower roller, the lower face of the strip being in contact with the second roller via the second polymer sheet and the upper face, called the free face, of the strip being in contact with the first roller via the current collector interposed between the first roller and the upper face, the second polymer sheet being, optionally, dissociated from the strip at the end of the co-rolling step, while the current collector remains attached to the upper face of the strip thus co-rolled at the end of the co-rolling step, thereby resulting in the assembly comprising the first flat electrode and the current collector.

[0099] This step is illustrated schematically in [Fig. 5], comprising the elements following: - strip 19 resulting from the rolling stage described above; - the upper roller 35; - the current collector 37 arranged between the band 19 and the upper roller 35; - the lower roller 39; - the second polymer sheet 27 arranged between the band 19 and the lower roller 39; It is understood that, as indicated by the arrow on the upper roller showing the direction of rotation of said roller and by the arrow on the lower roller showing the direction of rotation of said roller, said upper and lower rollers rotate in opposite directions to induce a movement of the tape from right to left, as well as the second polymer sheet and the current collector. In other words, the upper roller rotates clockwise, while the lower roller rotates counterclockwise.

[0100] As with the rolling step, the upper roller and the lower roller can belong to a rolling mill type device or a calender type device used conventionally to densify electrodes in a conventional lithium-ion battery manufacturing process.

[0101] The co-rolling step can be carried out hot and, more specifically, at a temperature ranging from 60°C to 120°C, preferably even more so, ranging from 80°C to 110°C, this temperature being able to be reached by heating the lower roller and the upper roller.

[0102] At the end of this step and, where applicable, once the strip has cooled, the second polymer sheet can be dissociated from the strip, i.e., it does not remain attached to the lower face of the latter, this dissociation being carried out advantageously via a drive roller (reference 41 on [Fig.6] similar to [Fig.5] except for the presence of this additional drive roller) located downstream of the lower roller, preferably at a predetermined distance, and positioned on the second polymer sheet and the strip and via a winding roller located downstream of the lower roller and the drive roller and in a detached position relative to them and connected to one end of the second polymer sheet, the rotation of the winding roller causing the polymer sheet to move towards the drive roller and then winding around the winding roller.More specifically, the drive roller is positioned at a predetermined distance determined by the time required to cool the web before the second polymer sheet is removed, thus preventing it from sticking to the roller. For example, for a lamination temperature of 80°C. and a line speed of 1 m / min, the predetermined distance must be greater than 20 cm. At the end of this co-lamination step, the strip is thus coated on the upper face by a current collector and has a free lower face, when the second polymeric sheet has been dissociated.

[0103] Regarding the current collector, it can be supplied by a distributor roller located upstream of the upper roller for the current collector.

[0104] The current collector can be, conventionally, a current collector in the form of a metal sheet and, more specifically, an aluminum sheet, when the prepared electrode is a positive electrode, or a copper, nickel or nickel-plated copper sheet, when the prepared electrode is a negative electrode.

[0105] Advantageously, the current collector may be in the form of a metal sheet, at least the face (namely, the underside of the current collector) intended to be in contact with the strip is modified to improve the adhesion of the strip to the current collector. This modification may consist of a surface treatment, for example, a treatment leading to the formation of a layer of particles on the surface, such as electrically conductive carbon particles, such as graphite, graphene, carbon nanotubes, activated carbon, or unactivated carbon nanofibers; metallic particles, for example, in the form of powder, fibers, or flakes; metal oxide particles; or electrically conductive polymer particles. The modification may also consist of a surface treatment selected from ablation or corrosion.

[0106] By way of example, a particular current collector is a surface-treated, chemically treated aluminum collector, known under the reference SDX™-ZM from the manufacturer Showa Denko.

[0107] Advantageously, the process of the invention is a continuous process, that is to say a process for which, during the whole duration of its implementation, there is no interruption between step a), step b), step c) and step d).

[0108] More specifically, the manufacturing process can be a continuous process, that is, a process that runs without interruption throughout its implementation, which means, in other words, that the whole is manufactured without interruption for the entire duration of the process. In other words, this means that steps a) to d) are carried out concurrently and without interruption for the entire duration of the process, which means, in other words, that at each instant t of the process duration, a fraction of the composition is subjected to the manufacturing step while another fraction of the composition is subjected to the strip forming step, and a fraction of the strip is subjected to the strip forming step. rolling and that another portion of the strip is subjected to the co-rolling step. It is also understood, in this case, that all optional steps of the process (for example, the drying step) are, where present, carried out continuously.

[0109] Different embodiments of a continuous process according to the invention are illustrated in Figures 7, 8, 9 and 10 attached hereto. For these different figures, the numerical references identical to those used for the preceding figures designate the same elements and will not be systematically described again when they have already been described elsewhere.

[0110] Figure 7 represents a first variant of the continuous process implementation. More specifically, the strip 19 is formed at the outlet of the sleeve 1 of the co-rotating twin-screw mixer using a flat die 17. The thickness of the strip is then reduced by rolling between an upper roller 21 and a lower roller 25 of a first rolling mill, a first polymer sheet 23 being intercalated between the upper roller 21 and the strip 19, the first polymer sheet being supplied via an unwinding roller 43 and a second polymer sheet 27 being intercalated between the strip 19 and the lower roller 25, said second sheet being supplied via an unwinding roller 45.After rolling, the first polymer sheet is separated from the web via a drive roller 33 located downstream of the upper roller at a predetermined distance and positioned on the first polymer sheet attached to the web, and via a winder roller 47 located downstream of the upper roller and the drive roller 33, and in a raised position relative to them, and connected to one end of the first polymer sheet. The predetermined distance depends on the temperature of the aforementioned rollers and the rolling speed.The strip from the rolling process is then conveyed in the direction of the arrow shown in the figure to a second rolling mill for co-rolling with a current collector. This co-rolling process consists of passing the strip between an upper roller 35 and a lower roller 39, the current collector 37 being interposed between the upper roller 35 and the strip 19, the current collector being supplied via an unwinding roller 49. After co-rolling, the second polymer sheet is separated from the strip via a drive roller 41 located downstream of the lower roller 39 positioned at a predetermined distance and positioned on the second polymer sheet attached to the strip, and via a winding roller 51 located downstream of the lower roller and the drive roller and being detached from the strip and connected to one end of the second polymer sheet.The predetermined distance is a function of the temperature of the aforementioned rollers and the lamination speed. After lamination, the strip coated with the current collector and free of the second polymeric sheet is wound onto a winding roller 53.

[0111] To adjust the tension of the tape 19 and the first and second polymer sheets, one or more movable drive rollers can be added, which allows for better control of this tension and ensures better alignment between the tape and the polymer sheets. These implementation variants, respectively second, third, and fourth, are illustrated in Figures 8, 9, and 10 with: - for [Fig.8], a movable drive roller 55 in contact with the current collector and positioned between the upper roller 35 and the winding roller 53, the other elements being identical to those of [Fig.7] and being designated by the same numerical references; - for [Fig.9], in addition to the movable drive roller 55 of [Fig.8], another movable drive roller 57 in contact with the second polymer sheet positioned between the lower roller 25 of the first rolling mill and the lower roller 39 of the second rolling mill, the other elements being identical to those of [Fig.7] and [Fig.8] and being designated by the same numerical references; - for the [Fig. 10], in addition to the mobile drive roller 55 and the other mobile drive roller 57, another mobile drive roller 59 in contact with the belt 19 downstream of the other mobile drive roller 57 and upstream of the upper roller 35 of the second rolling mill.

[0112] The process of the invention is also suitable for the preparation of a bifacial electrode, in other words in the context of the invention to an assembly comprising a first electrode deposited on a first face of the current collector and a second electrode deposited on a second face of the current collector, this process being able to adopt several embodiment variants.

[0113] According to a first embodiment, the process, in addition to the steps already described, includes the following features: - for step d) above, the second polymeric sheet is not dissociated from the strip; - after step d), a co-lamination step e) of the assembly from step d) with another strip, called second strip, comprising a polymer matrix trapping an electrolyte, said second strip being coated on its upper face by a polymer sheet, called third polymer sheet, by passing said assembly and the second strip between an upper roller and a lower roller, the lower roller being in contact with the second polymer sheet of the aforementioned assembly and, between the upper roller and the current collector of the assembly, is interposed the strip coated on its upper face by a polymer sheet, called third polymer sheet, said third polymer sheet being in direct contact with the upper roller; - after step e), a dissociation step of the second polymer sheet and a dissociation step of the third polymer sheet, whereby the result is the assembly comprising a first electrode deposited on a first face of the current collector and a second electrode deposited on a second face of the current collector.

[0114] This variant is illustrated in [Fig. 11] which details the co-lamination step e) and the subsequent dissociation steps with the following elements: - the band 19, called the first band, coated on its lower face by the second polymeric sheet 27 and on its upper face by the current collector 37; - an upper roller 61 and a lower roller 63; - a second strip 65 coated on its upper face with a polymeric sheet 67, called the third polymeric sheet, and having its lower face free; - the lower roller 63 being in contact with the second polymeric sheet 27 and the upper roller 61 being in contact with the third polymeric sheet 67, the first strip 19 and the second strip 65 being brought into contact by passing between the upper roller 61 and the lower roller 63, which means, in other words, that the first strip 19 and the second strip 65 are brought into contact via the current collector covering the first strip 19 and via the free lower face 66 of the second strip; - downstream of the upper roller 61, a drive roller 69 in contact with the third polymeric sheet 67 covering the upper face of the second strip 65 and downstream of this drive roller 69, a winding roller 71 connected to one end of the third polymeric sheet and in a raised position relative to the drive roller 69, by which means the third polymeric sheet 67 is, on the one hand, driven and, on the other hand, detached from the second strip; - downstream of the lower roller 63, a drive roller 73 in contact with the second polymer sheet 27 covering the lower face of the first strip 19 and downstream of this drive roller, a winding roller 75 connected to one end of the second polymer sheet 27 and in a position detached from the second strip relative to the drive roller 73, by which means the second polymer sheet is, on the one hand, driven and on the other hand, detached from the second strip; - a winding roller 77 linked to one end of the assembly comprising the first strip (which constitutes the first electrode) deposited on a first face of the current collector and the second strip (which constitutes the second electrode) deposited on a second face of the current collector.

[0115] Fig. 12 illustrates a variant similar to that shown in Fig. 11, except that a movable drive roller 79 is interposed between the upper roller 61 and the drive roller 69 to act on the band tension.

[0116] The second strip can be produced, up to the co-lamination step e), according to steps a), b) and c) as defined within the framework of the process of the invention.

[0117] According to a second embodiment, the process includes the following features: - In step d), the upper surface of the strip, referred to as the first strip, is in contact with the first roller via the current collector, which is itself in contact with the free surface of another strip, referred to as the second strip. This second strip comprises a polymer matrix trapping an electrolyte, and its other surface is coated with a polymer sheet, referred to as the third polymer sheet. In other words, between the first roller and the upper surface of the strip, in the direction from the first roller to the upper surface of the first strip, are the third polymer sheet deposited on the second strip, the second strip, and the current collector.

[0118] The second strip, up to the co-lamination step d), can be produced by a process according to the invention comprising steps a), b) and c).

[0119] This variant is illustrated in [Fig. 13], which details the simultaneous production of the two strips up to their contact via the current collector, with, more specifically, the boxed parts a) and a') schematically representing the rolling step of the first strip (part a)) and the rolling step of the second strip (part a')). For each of these parts, similar reference numerals are used where possible, except that they differ by the addition of a ' sign for the reference numerals in part a').

[0120] For each of the parts a) and a'), the strip (19 or 19') is formed at the outlet of the sleeve (1 or 1') of the co-rotating interpenetrating two-screw mixer using a flat die (17 or 17'). The thickness of the strip is then reduced by rolling between an upper roller (21 or 21') and a lower roller (25 or 25') of a first rolling mill, a first polymer sheet (23 or 23') being interleaved between the upper roller 21 and the strip 19 for part a) and between the lower roller 25' and the strip 19' for part a'), the first polymer sheet being supplied via an unwinding roller (43 or 43') and a second polymer sheet (27 or 27') being interleaved between the strip 19 and the lower roller 25 for part a) and between the upper roller 21' and the strip 19' for part a'), said second sheet being supplied via an unwinding roller (45 or 45').At the end of the rolling, the first polymer sheet is separated from the strip via two drive rollers 33 and 34 or 33' and 34' located downstream of the upper roller 21 for part a) or the lower roller 25' for part a') and positioned on the first polymer sheet attached to the strip and via a winder roller 47 or 47' located downstream of the upper roller for part a) and the lower roller for part a') and the drive rollers 33 and . 34 or 33' and 34' and in a detached position relative to these and connected to one end of the first relevant polymeric sheet.

[0121] In this [Fig. 13], part b) illustrates the co-rolling step common to the two rolled strips, by passing them between an upper roller 35 and a lower roller 39 and interposing between them the current collector 37 supplied by means of an unwinding roller 49, the two strips being conveyed to the second rolling mill by means of the two drive rollers 55 and 55'. Downstream of the upper and lower rollers, the second polymer sheets are detached from the strips by means of the respective drive rollers 41 and 41' and the winding rollers 51 and 51' connected to one end of said strips.

[0122] The resulting assembly thus formed is conveyed via a drive roller 55 to be wound and stored in a winding roller 53'.

[0123] Alternatively, still with the aim of producing an electrode-current collector assembly, the electrode of which comprises a polymer matrix trapping an electrolyte, the present invention also relates to a method for manufacturing an assembly comprising a first flat electrode comprising a polymer matrix trapping an electrolyte and a current collector, said method comprising the following steps: a) a step of preparing a composition comprising the ingredients intended to be used in the constitution of the first electrode, said step consisting of introducing and mixing the ingredients intended to be used in the constitution of the electrode in a mixer with two co-rotating interpenetrating screws rotating in a closed sleeve, at a temperature below 100°C; b) from the composition obtained in a), a step of forming a strip by passing said composition through a die;(c) a co-lamination step of the strip obtained in (b), by passing it between a first roller, called the upper roller, and a second roller, called the lower roller, a polymer sheet having an average surface roughness, called Ra, ranging from 0.01 pm to 1 pm being interposed between the first roller and the strip and a current collector being interposed between the second roller and the strip in order to avoid any direct contact between the rollers and the strip, the polymer sheet being dissociated from the strip at the end of the co-lamination step while the current collector remains attached to the strip at the end of the co-lamination step, thereby resulting in the assembly comprising the first flat electrode and the current collector.

[0124] This variant of the process is illustrated in [Fig. 14].In this figure, the strip 19 from the flat die (not shown) is laminated between an upper roller 81 and a lower roller 83 of a rolling mill, a polymer sheet 85 being intercalated between the strip 19 and the upper roller 81 and a current collector 87 being intercalated. between the band 19 and the lower roller 83. Downstream of the rollers, the polymer sheet 85 is separated from the band via a drive roller 89 positioned downstream of the upper roller on the polymer sheet itself positioned on the band.

[0125] This variant of the process is also suitable for preparing a bifacial electrode, otherwise in the context of the invention to an assembly comprising a first electrode deposited on a first face of the current collector and a second electrode deposited on a second face opposite to said first face of said current collector

[0126] The characteristics relating to steps a) and b), to the polymer sheet and to the current collector already described above are also valid for this variant.

[0127] In this case, the co-rolling step c') can be defined as a co-rolling step of the strip obtained in b), by passing it between a first roller, called the upper roller, and a second roller, called the lower roller; a polymer sheet being interposed between the first roller and the strip, called the first strip, which is in contact, via its underside, with a current collector; and Interposed between the second roller and the strip is said current collector in contact, via its lower face, with another strip, said second strip, comprising a polymer matrix trapping an electrolyte, this second strip being in contact via its lower face with another polymer sheet, the polymer sheet being dissociated from the first strip and the other polymer sheet being dissociated from the second strip at the end of the co-lamination step, thereby resulting in the aforementioned assembly.

[0128] Before the co-lamining step, the second strip can be produced by a process comprising the aforementioned steps a) and b).

[0129] This variant is illustrated in [Fig. 15] with the co-rolling step common to the first strip 19 and the second strip 19', each resulting from a passage through a flat die (17 and 17') of a composition obtained from a mixer (1 and 1'). The first and second strips are subjected to a passage in a rolling mill between an upper roller 81 and a lower roller 83, with the current collector 87, supplied by means of an unwinding roller 49', interposed between them. The first strip is in contact with the upper roller via a polymer sheet 85 supplied by an unwinding roller 43, and the second strip is in contact with the lower roller via a polymer sheet 85' supplied by an unwinding roller 43'. Downstream of the upper and lower rollers, the polymer sheets are detached from the strips concerned by means of the respective drive rollers 33 and 33. 33' and to the winding rollers 47 and 47' connected at one end of said sheets. The resulting assembly is conveyed and stored on a winding roller 53.

[0130] The invention will now be described in light of the examples given below, which are given by way of illustration and not limitation. Brief description of the figures

[0131] [Fig-1] is a diagram representing a mixer usable for implementing the process of the invention.

[0132] [Fig.2] is a diagram illustrating the band formation step via the passage of the composition obtained at the end of step a) through a die.

[0133] [Fig.3] is a diagram illustrating the rolling step of the process of the invention.

[0134] [Fig.4] is a diagram illustrating the rolling step of the process of the invention with an additional specific feature.

[0135] [Fig.5] is a diagram illustrating the co-lamination step of the process of the invention.

[0136] [Fig.6] is a diagram illustrating the co-lamination step of the process of the invention with an additional specific feature.

[0137] [Fig.7] is a diagram illustrating a first variant of the implementation of the continuous process of the invention.

[0138] [Fig.8] is a diagram illustrating a second variant of the implementation of the continuous process of the invention.

[0139] [Fig.9] is a diagram illustrating a third variant of the implementation of the continuous process of the invention.

[0140] [Fig. 10] is a diagram illustrating a fourth variant of the implementation of the continuous process of the invention.

[0141] [Fig. 11] is a diagram illustrating the implementation of the continuous process of the invention for the production of a bifacial electrode according to a first embodiment variant.

[0142] [Fig. 12] is a diagram illustrating the implementation of the continuous process of the invention for the production of a bifacial electrode according to a first embodiment variant with an additional specificity.

[0143] [Fig. 13] is a diagram illustrating the implementation of the continuous process of the invention for the production of a bifacial electrode according to a second embodiment.

[0144] [Fig. 14] is a diagram illustrating the implementation of a new form of the process of the invention.

[0145] [Fig. 15] is a diagram illustrating the implementation of this new form of the process of the invention for the continuous production of a bifacial electrode.

[0146] Detailed description of particular embodiments EXAMPLE 1

[0147] In the following example, the following ingredients are used: * Polymer-1: VDF-AA (0.9% by moles)-HFP (2.4% by moles) copolymer having an intrinsic viscosity of 0.28 L / g in dimethylformamide (DMF) at 25°C and a melting point of 148°C, VDF corresponding to vinylidene fluoride and AA corresponding to acrylic acid; *Polymer-2: VDF-HFP (2.5% by moles)-HEA (0.4% by moles) copolymer having an intrinsic viscosity of 0.117 L / g in DMF at 25°C and a melting point of 154.2°C, VDF corresponding to vinylidene fluoride and HFP corresponding to hexafluoropropene; * Polymer (Fl): VDF-AA (0.5% by moles)-HFP (6.5% by moles) copolymer having an intrinsic viscosity of 0.32 L / g in dimethylformamide (DMF) at 25°C and a melting point of 127°C, VDF corresponding to vinylidene fluoride and AA corresponding to acrylic acid; *Electronic conductor (IEC): Super™ C65 carbon black marketed by IMERIS; *Electronic conductor (CE2): VGCF™-H carbon fibers marketed by SHOWA DENKO; *Graphite: 75% SMG-N-HE1 (Hitachi Chemical Co„ Ltd.) / 25% TIMREX™ SFG6; *NMC622 cathode material: HX12th marketed by UMICORE; *Liquid medium (Ll): ethylene carbonate (EC) / propylene carbonate (PC) (1:1) containing LiPF6 IM and 2% vinylene carbonate (VC); *TSPI: 3-(triethoxysilyl)propyl isocyanate; *DBTDL: dibutyltin dilaurate; and *TEOS: tetraethoxysilane Si(OC2H5)4.

[0148] Initially, a negative electrode is prepared and deposited on a current collector in accordance with the process of the invention.

[0149] To do this, the following components, in the proportions shown below, are introduced into a Thermofisher twin-screw co-rotating mixer with a diameter of 24 mm (reference TSE24): Graphite: mass proportion of 69.35%. Polymer (Fl): mass proportion of 3.65%. Liquid medium (Ll): mass proportion of 27%.

[0150] The components are mixed at a temperature below 100°C with a screw rotation speed of 300 rpm and a total mass flow rate of 4.5 kg / h. A continuous strip is formed at the mixer outlet using a 600 µm flat die. Immediately after exiting the die, the continuous strip is passed between the rollers of an INGECAL rolling mill, with roller diameters of 150 mm, at 80°C, and between a 23 µm thick HOSTAPHAN™ MK PET film conveyed by the upper roller and a copper current collector of a thickness of 10 µm conveyed by the lower roller, the line speed being between 3.5 and 4.5 m / min and the gap between the rollers being set at 100 µm. The resulting ionogel negative electrode has a final thickness of 115 µm and a total weight of 19.2 mg / cm² (including the electrolyte), which represents a surface capacitance of 4.7 mAh / cm².

[0151] In a second step, a positive electrode is prepared according to the following procedure. A solution of polymer-1 in acetone is prepared at 40°C and then cooled to room temperature. Next, 96.9% by mass of NMC622, 2.1% by mass of IEC electronic conductor, and 1% by mass of CE2 electronic conductor are added to the polymer-1 solution in a mass ratio of 96 / 4 (active material + conductors / polymer-2). Subsequently, the liquid medium (L1) is added to the mixture in a mass ratio of [mLi / (mLi + polymer-1)] x 100 of 75.2%.

[0152] The mixture is then coated to a constant thickness onto a 20 µm thick Al current collector using a comma bar roll-to-roll coating machine. The solvent is then evaporated in-line at a temperature below 70°C, thus producing the ionogel positive electrode. The electrode is finally calendered to a final thickness of 118 µm. The total weight of the electrode is 28.4 mg / cm² (including the electrolyte), which corresponds to a surface capacitance of 4.2 mAh / cm².

[0153] In a third step, a membrane is prepared according to the following process. Polymer-2 (40 g) is dissolved in 275 g of acetone at 60°C, yielding a solution containing 12.7% by mass of polymer-2. DBTDL (0.21 g) is added, and the solution is homogenized at 60°C. TSPI (0.82 g) is then added. The amount of DBTDL is calculated to be 10% molar to the TSPI. The amount of TSPI is itself calculated to be 0.55% molar to polymer-2. The solution is maintained at 60°C for 90 min to allow the isocyanate functional groups to react with the hydroxyl groups of polymer-2.

[0154] Next, the liquid medium (Ll) is added to the solution in a mass proportion of [mLi / (mLi + m pOiymer-2)] x 100 of 80%. After homogenization at 60°C, formic acid is added followed by TEOS. The amount of TEOS is calculated respecting the mass proportion (m(SiO2) / m(pOiymer-2)) of 10%. The amount of formic acid is calculated from the equation n(formic acid) / n(TEOS) = 2.6.

[0155] All ingredients were introduced into the solution mixture under an argon atmosphere.

[0156] The mixture is then coated to a constant thickness onto a PET substrate using a comma bar-type roll-to-roll coating machine. The solvent is then evaporated in-line at a temperature below 70°C, thus producing the membrane. The thickness of the membrane thus produced is 45 µm.

[0157] Finally, three flexible "Pouch Cell" type cells are prepared from the elements manufactured above. More specifically, three flexible cells were assembled using a negative ionogel electrode according to the invention of Example 1, characterized by a weight of 19.2 mg / cm2, i.e. a surface capacitance of 4.7 mAh / cm2, a positive ionogel electrode characterized by a weight of 28.4 mg / cm2, i.e. a surface capacitance of 4.2 mAh / cm2, and a membrane as described previously.

[0158] The active surface of the negative ionogel electrode is 12.25 cm2 and that of the positive ionogel electrode is 10.24 cm2.

[0159] The discharge capacity values ​​for these three cells were determined at different discharge rates. The results are shown in the table below, with the three cells being labeled Cell 1, Cell 2 and Cell 3 respectively. [Tables 1] Cydage conditions Discharge capacity °C Regime Test number Cell 1 L ë l I il ? 6 2 Cell 3 22 C / 2O- D / 20 0 39.18 38.81 39.02 22 1 38.51 38.16 38.33 22 2 37.44 37.09 37.26 22 C / 10 - D / 10 37.11 36.79 36.73 22 4 35.41 35.36 34.93 22 5 35.11 35.17 34.65 22 6 34.87 35.06 34.45 22 7 34.57 34.88 34.16 22 C / 5- D / 5 3. 31.00 32.34 30.45 22 9: 30.71 32.23 30.19 22 10 30.42 32.14 30.00 22 11 30.0 7 32.00 29.73 22 12 29.79 31.92 29.43 22 C / 5-D / 2 13 24.45 28.68 24.31 22 14 24.43 28.74 w U 22 15 23.86 28.32 24.33 22 16 23.48 28.30 23.66 22 17 23.23 28.16 23.29 22 C / 5-D 18 9.94 14.41 8.93 22 19 9.79 14.50 8.60 22 20 9.71 14.50 8.58 22 21 9.56 14.53 8.52 22 22 8.68 14.30 8.49 22 C / 5-2D 23 5.04 2.65 22 24 2.75 4.96 2.79 22 25 2.73 4.96 2.81 22 26 2.71 4.98 2.84 22 27 2.73 5.00 2.87 22 Ç / 20- D / 20 28 34.23 35.20 34.37 22 29 34.14 35.18 34.03 22 30 33.97 35.09 33.66 22. 31 33.79 34.97 33.30 22 32 33.60 34.84 33.08 22 33 39.18 38.81 39.02 22 34 38.SI 38.16 38.33

[0160] It is clear from the above results that the cells are functioning correctly and that the values ​​are repeatable. EXAMPLE 2

[0161] This example is a test aimed at optimizing the characteristics of the polymer sheets used as a function of the electrode and, in particular, in terms of surface roughness and energy.

[0162] Indeed, in the context of the invention, in order to be able to optimally remove a polymeric sheet without detaching the electrode strip from its collector, the optimal characteristics of this polymeric sheet and, more particularly, of a polymeric sheet made of poly(ethylene terephthalate).

[0163] Initially, for a graphite-based electrode strip similar to that defined in Example 1 above, he tested various polymeric sheets of poly(ethylene terephthalate) with different roughnesses to optimally determine a roughness range compatible with the rolling and co-rolling steps. These tests revealed that sheets particularly compatible with these steps for a graphite-based electrode strip are those with a high average surface roughness (Ra), specifically between 0.01 pm and 1 pm, and more advantageously between 0.3 pm and 0.7 pm.

[0164] On the other hand, low roughness (and, more particularly, less than 0.01 pm) poly(ethylene terephthalate) polymer sheets tend to remain stuck to the graphite-based electrode strip, thus leaving the copper current collector separated from the electrode at the end of the process.

[0165] In a second step, tests were carried out with the high-roughness sheets to determine compatible surface energy ranges that would allow for easy removal of said sheets without causing the electrode strip to detach from the current collector. These tests showed that the surface energy of the polymer sheet should advantageously be lower than the surface energy of the electrode strip and, preferably, should be less than 40 mN / m.

[0166] Furthermore, it should be noted that the electrode strip should advantageously have a surface energy lower than that of the current collector to which it is associated, in order to have optimal adhesion between them.

[0167] Therefore, it can be deduced that advantageously, the surface energy of the polymer film is less than the surface energy of the electrode strip, which is less than the surface energy of the current collector.

[0168] In a third step, using PET sheets with high roughness (around 0.30 pm) and a surface energy of less than 40 mN / m (more precisely, 26.7), different thicknesses (12, 19, and 125 pm, respectively) were tested, along with their impact on the adhesion and delamination properties of the sheets. The results show that the polymer sheet must be sufficiently thin to be able to be [fa] The coating is removed, but it must also be thick enough to retain sufficient mechanical properties for the lamination and co-lamination stages. Thus, it is deduced from these tests that a PET sheet can advantageously have a thickness ranging from 6 µm to 75 µm, preferably from 10 µm to 30 µm.

Claims

Demands

1. A method for manufacturing an assembly comprising a first flat electrode comprising a polymer matrix trapping an electrolyte and a current collector (37), said first electrode being deposited on a face of said current collector, said method comprising the following steps: a) a step of preparing a composition comprising the ingredients intended to be part of the constitution of the first electrode, said step consisting of introducing and mixing the ingredients intended to be part of the constitution of the electrode in a mixer with two interpenetrating screws (3, 5) rotating co-rotating in a closed sleeve (1), at a temperature below 100C; b) from the composition obtained in a), a step of forming a strip (19) by passing said composition through a die (17); c) a step of rolling the strip (19) obtained in b), by passing it between a first roller, called the upper roller (21), and a second roller, called the lower roller (25), a first polymer sheet (23) being interposed between the first roller and the strip (19) and a second polymer sheet (27) being interposed between the second roller and the strip (19), the first polymer sheet (23) being dissociated from the strip (19) at the end of the rolling step while the second polymer sheet (27) remains attached to the strip (19) thus rolled at the end of the rolling step, thereby resulting in a rolled strip (19) coated on one face, called the lower face (31), by the second polymer sheet (27) and whose face opposite the lower face, called the upper face (29), is free; d) a co-lamination step of the laminated strip (19) obtained in c) with a current collector (37) by passing the strip between a first roller, called the upper roller (35), and a second roller, called the lower roller (39), the lower face (31) of the strip (19) being in contact with the second roller via the second polymer sheet (27) and the upper face (29) being in contact with the first roller via the current collector (37) interposed between the first roller and the upper face (29), the second polymer sheet (27) being optionally detached from the strip (19) at the end of the co-lamination step while the current collector (37) remains attached to the upper face (29) of the strip (19) thus colaminated at the end of the colamization step, thereby resulting in the assembly comprising the first flat electrode and the current collector (37).

2. A manufacturing process according to claim 1, wherein the composition comprises, as constituent ingredients of the electrode: - at least one active electrode material; - at least one polymer intended to be part of the constitution of the polymer matrix; - an electrolyte; - optionally at least one electronically conductive additive.

3. A manufacturing method according to claim 2, wherein the polymer(s) are selected from gelling polymers capable of gelling on contact with the electrolyte and thus trapping the electrolyte.

4. A manufacturing process according to claim 2 or 3, wherein the electrolyte is a liquid electrolyte comprising at least one organic solvent, at least one metallic salt and optionally an additive belonging to the category of carbonate compounds.

5. A manufacturing method according to any one of claims 1 to 4, wherein the die (17) of step b) is a flat die.

6. A method according to any one of claims 1 to 5, wherein the first polymeric sheet (23) and the second polymeric sheet (27) are polyester sheets.

7. A method according to any one of claims 1 to 6, wherein the first polymeric sheet (23) and the second polymeric sheet (27) are sheets of poly(ethylene terephthalate) or poly(ethylene naphthalate), preferably of poly(ethylene terephthalate).

8. A method according to any one of claims 1 to 7, wherein the first polymeric sheet (23) and the second polymeric sheet (27) are of the same nature.

9. A method according to any one of claims 1 to 8, wherein the first polymeric sheet (23) and / or the second polymeric sheet (27) has at least one rough face, in particular, the face intended to be in contact with the strip (19).

10. A method according to any one of claims 1 to 9, wherein the first polymeric sheet (23) and / or the second polymeric sheet (27) has an average surface roughness of 0.01 pm to 1 pm, preferably of 0.3 pm to 0.7 pm.

11. A method according to any one of claims 1 to 10, wherein the first polymeric sheet (23) and / or the second polymeric sheet (27) has a surface energy of less than 40 mN / m.

12. A method according to any one of claims 1 to 11, wherein the first polymeric sheet (23) and / or the second polymeric sheet (27) has a thickness of 6 pm to 75 pm, preferably 10 pm to 30 pm.

13. A method according to any one of claims 1 to 12, wherein the rolling step is carried out at a temperature ranging from 60°C to 120°C.

14. A method according to any one of claims 1 to 13, wherein the current collector (37) is in the form of a metal sheet.

15. A method according to any one of claims 1 to 14, wherein the current collector (37) is in the form of a metal sheet, at least the face intended to be in contact with the strip (19) is subject to a modification to improve the adhesion of the strip (19) to the current collector (37).

16. A method according to claim 15, wherein the modification consists of a treatment leading to the formation of a layer of particles on the surface of the current collector (37) or of a surface treatment selected from ablation or corrosion.

17. A process according to any one of claims 1 to 16, which is a continuous process.

18. A method according to any one of claims 1 to 17, which is a method for preparing an assembly comprising a first flat electrode deposited on a first face of the current collector (37) and a second flat electrode deposited on a second face of the current collector, said second face being opposite the first face, wherein: - for the aforementioned step d), the second polymer sheet (27) is not dissociated from the strip (19); - after step d), a co-lamination step e) of the assembly from step d) with another strip, referred to as the second strip (65), comprising a polymer matrix trapping an electrolyte, said second strip (65) being coated on its upper face by a polymer sheet, referred to as the third polymer sheet (67), by passing said assembly and the second strip (65) between an upper roller (61) and a lower roller (63), the lower roller (63) being in contact with the second polymeric sheet (27) of the aforementioned assembly and, between the upper roller (61) and the current collector (37) of the assembly, is interposed the strip (65) coated on its upper face by a polymeric sheet, said third polymeric sheet (67), said third polymeric sheet (67) being in direct contact with the upper roller (61); - after step e), a step of dissociation of the second polymeric sheet (27) and a step of dissociation of the third polymeric sheet (67), whereby the assembly results comprising a first electrode deposited on a first face of the current collector (37) and a second electrode deposited on a second face of the current collector.

19. A method according to any one of claims 1 to 17, which is a method for preparing an assembly comprising a first flat electrode deposited on a first face of the current collector (37) and a second flat electrode deposited on a second face of the current collector, said second face being opposite the first face, wherein, in step d), the upper face of the strip, said first strip (19), is in contact with the first roller via the current collector itself in contact with the free face of another strip, said second strip (19'), comprising a polymer matrix trapping an electrolyte said second strip (19') being coated on another face by a polymer sheet, said third polymer sheet.

20. A method for manufacturing an assembly comprising a first flat electrode including a polymer matrix trapping an electrolyte and a current collector (87), said method comprising the following steps: a) a step of preparing a composition comprising the ingredients intended to form part of the first electrode, said step consisting of introducing and mixing the ingredients intended to form part of the electrode in a mixer with two co-rotating interpenetrating screws rotating in a closed barrel, at a temperature below 100°C; b) from the composition obtained in a), a step of forming a strip (19) by passing said composition through a die; c) a step of co-laminating the strip (19) obtained in b) by passing

21.

22.

23. of this between a first roller, called upper roller (81), and a second roller, called lower roller (83), a polymer sheet (85) having an average surface roughness ranging from 0.01 pm to 1 pm being interposed between the first roller and the strip (19) and a current collector (87) being interposed between the second roller and the strip (19) in order to avoid any direct contact between the rollers and the strip (19), the polymer sheet (85) being dissociated from the strip (19) at the end of the co-rolling step while the current collector (87) remains attached to the strip (19) at the end of the co-rolling step, thereby resulting in the assembly comprising the first flat electrode and the current collector (87). Manufacturing method according to claim 20, wherein the die in step b) is a flat die. A method according to claim 20 or claim 21, which is a method for manufacturing an assembly comprising the first electrode deposited on a first face of the current collector (87) and a second electrode deposited on a second face opposite to said first face of said current collector, wherein step c') is a step of co-rolling the strip (19) obtained in b), by passing the latter between a first roller, called upper roller (81), and a second roller, called lower roller (83); a polymer sheet (85) being interposed between the first roller and the strip, called the first strip (19), which is in contact, via its underside, with a current collector (87); and between the second roll and the strip (19) are interposed said current collector (87) in contact, via its lower face with another strip, said second strip (19'), the latter being in contact via its lower face with another polymer sheet (85'), the polymer sheet (85) being dissociated from the first strip (19) and the other polymer sheet (85') being dissociated from the second strip (19') at the end of the co-rolling step, whereby the assembly results comprising the first electrode deposited on a first face of the current collector (87) and a second electrode deposited on a second face opposite to said first face of said current collector. A process according to claim 22, wherein, prior to the co-rolling step, the second strip (19') is produced by a process comprising steps a) and b) as defined in claim 20.

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