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WO2025193055A1 - Composition d'électrode pour la fabrication d'électrode sèche, électrode sèche formée à l'aide d'une composition d'électrode, batterie secondaire comprenant une électrode sèche, et procédé et dispositif de fabrication d'électrode sèche utilisant une composition d'électrode - Google Patents

Composition d'électrode pour la fabrication d'électrode sèche, électrode sèche formée à l'aide d'une composition d'électrode, batterie secondaire comprenant une électrode sèche, et procédé et dispositif de fabrication d'électrode sèche utilisant une composition d'électrode

Info

Publication number
WO2025193055A1
WO2025193055A1 PCT/KR2025/099697 KR2025099697W WO2025193055A1 WO 2025193055 A1 WO2025193055 A1 WO 2025193055A1 KR 2025099697 W KR2025099697 W KR 2025099697W WO 2025193055 A1 WO2025193055 A1 WO 2025193055A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrode
manufacturing
dry
binder
dry electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/KR2025/099697
Other languages
English (en)
Korean (ko)
Inventor
김종은
서광석
서민원
박종호
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cnp Solutions Co Ltd
Original Assignee
Cnp Solutions Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020240075451A external-priority patent/KR20250138611A/ko
Application filed by Cnp Solutions Co Ltd filed Critical Cnp Solutions Co Ltd
Publication of WO2025193055A1 publication Critical patent/WO2025193055A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a technology related to a dry electrode, which is an electrode manufactured by a dry method, and more specifically, to a novel electrode composition for manufacturing a dry electrode, which simplifies the manufacturing process by omitting a process that was essential in the prior art for manufacturing an electrode without a solvent by a dry method and provides a dry electrode of excellent quality, a dry electrode formed by the electrode composition, a secondary battery including the dry electrode, and a method and device for manufacturing a dry electrode using the electrode composition.
  • Secondary batteries such as lithium-ion batteries, are electrical storage devices that operate through electrochemical reactions in electrode layers composed of active materials, conductive materials, and binders.
  • the electrochemical properties of secondary batteries are determined by various factors, including the type and content of each component, their compositional ratio, and the electrode manufacturing method.
  • electrode manufacturing methods involve mixing and dispersing all components in a solvent to create a uniform electrode composition slurry, which is then applied to a metal plate as a current collector and dried to produce an electrode with a certain thickness (wet electrode method). Because this method has been used for a long time, the manufacturing process is already stable and the yield is very high. However, this method has many inconveniences in the manufacturing process, such as the mandatory installation of a drying chamber for solvent removal and the need to recover all evaporated solvent to prevent air pollution. Consequently, the equipment and manufacturing costs are high.
  • particulate polytetrafluoroethylene is used in the manufacture of dry electrodes using a dry method. This is because PTFE is known to fiberize (become thinner and longer) when subjected to shear force, effectively binding the active material and conductive additives.
  • the conventional method for manufacturing dry electrodes comprises the steps of: (1) preparing a kneaded material (compound) by putting all of the components of the electrode, i.e., the active material, binder, and conductive additive, into a kneader (e.g., internal mixer; kneader) and kneading them; (2) a grinding step for grinding the kneaded material into an appropriate size to create particles suitable for calendering; (3) a calendering step for manufacturing a dry electrode sheet using a calender; and (4) a step for attaching the dry electrode sheet onto a metal plate.
  • the dry electrode is manufactured through the following steps (hereinafter referred to as the "kneading/grinding/calendering method").
  • the above-described dry electrode manufacturing method namely the kneading/grinding/calendering method
  • PTFE particles known by the trade name Teflon
  • Teflon are a fluorinated polymer and are known to have high releasability and poor adhesion to other substances.
  • Teflon a fluorinated polymer
  • a dry electrode is manufactured by applying high pressure, the shrinkage and expansion caused by the temperature change during repeated charge and discharge processes cause minute gaps between the components in the electrode layer, increasing the possibility of the electrode layer peeling off from the metal plate, which serves as the current collector. This leads to various problems, such as a decline in the electrochemical properties of the dry electrode.
  • PVDF polyvinylidene fluoride
  • PAA polyacrylic acid
  • CMC carboxymethyl cellulose
  • acrylonitrile copolymers will interfere with the fiberization of PTFE, making dry electrode manufacturing very difficult.
  • PTFE particles and acrylonitrile copolymer binder particles are dry blended at a weight ratio of 50:50 to create a binder mixture and then kneaded, the kneading will not proceed to the extent that torque is applied during the kneading operation. Furthermore, if this mixture is passed through a calendaring roll, it will crumble and fall down as it passes through the roll, preventing the formation of a dry electrode sheet.
  • the content of the adhesive binder must be increased to increase the adhesiveness of the dry electrode, but in this case, there is a problem that manufacturing a dry electrode sheet becomes very difficult.
  • the purpose of the present invention is to provide a novel electrode composition for manufacturing a dry electrode, which can improve the adhesive strength with the electrode plate of a dry electrode and the bonding strength between each component within the electrode without reducing the surface forming ability of the dry electrode sheet during the manufacturing of the dry electrode.
  • Another object of the present invention is to provide a dry electrode manufacturing method and device that can increase economic efficiency by simplifying the manufacturing process by omitting the process that was essential in the prior art using the electrode composition for manufacturing the dry electrode described above and provide a dry electrode of better quality.
  • Another object of the present invention is to provide a dry electrode having excellent adhesive strength with a metal electrode plate as a current collector and excellent bonding strength between each component in the electrode by using an electrode composition for manufacturing a dry electrode having the above-described configuration, and to provide a secondary battery including the electrode capable of effectively maintaining stable electrochemical characteristics.
  • the present invention provides an electrode composition for manufacturing a dry electrode, which comprises 90-98 wt% of an active material, 1.0-5 wt% of a binder, and 1.0-5 wt% of a surface forming agent.
  • the surface forming agent is a nanomaterial having at least one shape selected from the group consisting of a tube shape, a ribbon shape, and a fiber shape.
  • the surface forming agent is a carbon nanotube in the form of a lump or bundle having a size of 0.2-50 microns.
  • the binder is a simple mixture of the fiberizable fluorinated resin and another binder resin, or a core-shell structure composite binder formed such that a core made of the fiberizable fluorinated resin and a shell made of another binder resin surround the core.
  • the other binder resin is a copolymer comprising at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), carboxymethyl cellulose, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer; or at least one selected from the group consisting of acrylonitrile-based monomers, carboxyl-based monomers, and glycol-based monomers.
  • PVDF polyvinylidene fluoride
  • PAA polyacrylic acid
  • carboxymethyl cellulose carboxymethyl cellulose
  • styrene-butadiene copolymer styrene-butadiene copolymer
  • acrylonitrile-butadiene copolymer or at least one selected from the group consisting of acrylonitrile-based monomers, carboxyl-based monomers, and glycol-based monomers.
  • the carboxylic monomer is at least one selected from the group consisting of acrylic acid, acrylate, maleic acid, and maleic anhydride.
  • the content of the fiberizable fluorine resin included in the binder is 50% by weight or less of the total weight of the binder.
  • the surface-forming agent further comprises 1 to 100 parts by weight of at least one selected from the group consisting of conductive carbon black, graphene, carbon nanoplates, and graphene nanoplates, per 100 parts by weight of the surface-forming agent.
  • the present invention provides a method for manufacturing a dry electrode, including a step of preparing an electrode composition for manufacturing a dry electrode by stirring and mixing an active material, a binder, and a surface forming agent; a calendering step of manufacturing an electrode material layer sheet by calendering the electrode composition; and a rolling step of attaching the electrode material layer sheet to a support film or a metal electrode plate and then rolling it.
  • the calendaring step and the rolling step are performed continuously on the same line.
  • the calendering roll is heated to 50°C to 200°C when performing the calendering.
  • the electrode composition for manufacturing a dry electrode is any one of the electrode compositions for manufacturing a dry electrode described above.
  • the content of the fiberizable fluorine resin included in the binder in the electrode composition for manufacturing the dry electrode is 80% by weight or less of the total weight of the binder.
  • the electrode composition for manufacturing a dry electrode further comprises 1 to 100 parts by weight of at least one selected from the group consisting of conductive carbon black, graphene, carbon nanoplates, or graphene nanoplates per 100 parts by weight of the surface-forming agent.
  • the present invention provides a dry electrode manufacturing device comprising: a stirring device for stirring and mixing an electrode composition for manufacturing a dry electrode, including an active material, a binder, and a surface forming agent; a calender device for forming the stirred and mixed electrode composition into an electrode material layer sheet; and a rolling device for attaching and pressing the electrode material layer sheet by positioning it on at least one surface of a support film or a metal electrode plate.
  • the calendar device is set to a heating condition of 50°C to 200°C.
  • the calendar device and the rolling device are located on the same line.
  • the electrode composition for manufacturing a dry electrode is any one of the electrode compositions for manufacturing a dry electrode described above.
  • the content of the fiberizable fluorine resin included in the binder in the electrode composition for manufacturing the dry electrode is 80% by weight or less of the total weight of the binder.
  • the electrode composition for manufacturing a dry electrode further comprises 1 to 100 parts by weight of at least one selected from the group consisting of conductive carbon black, graphene, carbon nanoplates, or graphene nanoplates per 100 parts by weight of the surface-forming agent.
  • the present invention provides a dry electrode comprising any one of the above-described electrode compositions for manufacturing a dry electrode.
  • the content of the fiberizable fluorine resin included in the binder in the electrode composition for manufacturing the dry electrode is 80% by weight or less of the total weight of the binder.
  • the electrode composition for manufacturing a dry electrode further comprises 1 to 100 parts by weight of at least one selected from the group consisting of conductive carbon black, graphene, carbon nanoplates, or graphene nanoplates per 100 parts by weight of the surface-forming agent.
  • the present invention provides a secondary battery including the above-described dry electrode.
  • the electrode composition for manufacturing a dry electrode of the present invention described above can improve the adhesive strength with the electrode plate of the dry electrode and the bonding strength between each component in the electrode without reducing the surface forming ability of the dry electrode sheet during the manufacturing of the dry electrode.
  • the dry electrode manufacturing method and device of the present invention by using the electrode composition for manufacturing the dry electrode described above, the kneading process and the grinding process, which are processes essential in the prior art, are omitted, thereby simplifying the manufacturing process, and in order to improve adhesiveness, a considerable amount of a binder for existing secondary batteries is mixed in order to minimize the content of PTFE, so that a dry electrode can be easily manufactured, thereby increasing economic efficiency and providing a dry electrode of superior quality.
  • the dry electrode of the present invention has excellent adhesive strength with a metal electrode plate as a current collector and bonding strength between each component in the electrode by using the electrode composition for manufacturing a dry electrode having the above-described configuration, and also has the effect of improving long-term life characteristics, and the secondary battery of the present invention can effectively maintain stable electrochemical characteristics by including the dry electrode.
  • Figure 1 is an actual appearance of a dry electrode material layer sheet according to an embodiment of the present invention (surface forming agent: untreated carbon nanotubes).
  • Figure 2 is an actual appearance of a dry electrode material layer sheet according to an embodiment of the present invention (surface forming agent: boron nitride nanotube).
  • Figure 3 is a cross-sectional photograph of a dry electrode formed using an electrode composition for manufacturing a dry electrode according to an embodiment of the present invention.
  • Figure 4 shows the results of electrochemical impedance spectroscopy (EIS) measurement of a coin cell according to an embodiment of the present invention.
  • Figure 5 shows the results of a charge/discharge cycle test of a coin cell including a dry electrode according to an embodiment of the present invention.
  • first and second may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component,” and similarly, a second component could also be referred to as a "first component.”
  • temporal order when described as ‘after’, ‘following’, ‘next to’, ‘before’, etc., it also includes cases where it is not continuous, unless ‘right away’ or ‘directly’ is used.
  • the present invention is not limited to the embodiments described herein and may be embodied in other forms.
  • the same reference numbers are used to designate the same components.
  • detailed descriptions of known components or functions will be omitted if they are deemed to obscure the gist of the present invention.
  • the technical features of the present invention are a novel electrode composition for manufacturing a dry electrode, which simplifies the manufacturing process by omitting the kneading process and the grinding process, which are processes essential in the prior art when manufacturing a dry electrode, and improves the adhesive strength with the electrode plate of the dry electrode and the bonding strength between each component in the electrode without reducing the surface forming ability of the dry electrode sheet, a dry electrode formed with the electrode composition, a secondary battery including the dry electrode, and a method and device for manufacturing a dry electrode using the electrode composition.
  • PTFE polymer that stretches and becomes thin and long when a shear force is applied, i.e., fibers, and is therefore used as a binder for manufacturing dry electrodes.
  • PTFE has the disadvantage of poor adhesion to other materials due to its high releasability.
  • PTFE can be made to adhere together with the active material and conductive additives by applying high pressure, there is a high possibility that interfacial peeling will occur at the interface between each component in the dry electrode and the electrode plate when repeated expansion/contraction due to heating/cooling during use in a secondary battery. This can ultimately lead to a decline in electrochemical performance during charge/discharge cycle tests, and there was a problem that it could generate hydrogen fluoride, a toxic gas, in the event of a fire.
  • PTFE which is a binder for dry processes
  • another binder or, if PTFE cannot be completely replaced, to minimize the PTFE content by using a mixed binder in which PTFE is mixed with another binder.
  • other binders that are to be mixed with PTFE are almost impossible to fiberize like PTFE, so not only cannot other binders replace PTFE, but also, mixing another binder with PTFE causes a problem in that the sheet forming ability is rapidly reduced.
  • the present invention includes an electrode sheeting agent in the electrode composition during the manufacture of a dry electrode, thereby improving the sheet forming ability of the dry electrode to the extent that the calendaring process can be performed directly without performing the kneading process and the grinding process, which are pretreatment processes for fiberization, even when the content of the fiberizing polymer, i.e. PTFE, which had to be used at 100 wt% in the prior art, is used at 80 wt% or less, preferably 50 wt% or less, and more preferably 30 wt% or less.
  • PTFE fiberizing polymer
  • the electrode composition for manufacturing a dry electrode of the present invention comprises 90-98 wt% of an active material, 1.0-5 wt% of a binder, and 1.0-5 wt% of a planarizing agent.
  • the composition ratio of each component is experimentally determined, and if it is below the lower limit of each component, the effect of each component is not realized, which is disadvantageous, and if it exceeds the upper limit, each component is used excessively more than necessary, which reduces economic feasibility or causes electrochemical performance to not be realized properly, which is disadvantageous.
  • the binder content is low, less than 1.0 wt%, the electrode surface is not properly formed during the manufacture of the electrode, which is disadvantageous, and if the content is 5 wt% or more, the electrode surface of the dry electrode is well formed, but the active material content is relatively low, making it difficult to realize electric capacity, which may be disadvantageous.
  • the planarizing agent if the content is less than 1.0 wt%, the planarizing ability is reduced, which is disadvantageous, and if it is 5 wt% or more, the tubular planarizing agent is too abundant, which may result in an unclean appearance and many defects, which may be disadvantageous.
  • the active material may be a positive electrode active material or a negative electrode active material, and may be any one selected from the group consisting of alkali metal elements, alkaline earth metal elements, manganese, nickel, cobalt, aluminum, iron, phosphorus, tin, titanium, graphite, silicon, silicon oxide, sulfur, and combinations thereof.
  • the alkali metal element may be any one selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium
  • the alkaline earth metal element may be any one selected from the group consisting of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
  • Be beryllium
  • Mg magnesium
  • Ca calcium
  • Sr strontium
  • Ba barium
  • Ra radium
  • the active material may have a structure further including a coating layer formed on its surface.
  • the surface forming agent may be a thin and long nanomaterial having a diameter in the nanometer range and a length in the several to several hundred microns range.
  • the surface forming agent is not intended to improve surface adhesion properties, but rather is used together with each component forming the electrode, i.e., the active material and the binder, to cause these components to become entangled with each other, i.e., to form a surface or sheet, and therefore may be a nanomaterial having one or more shapes selected from the group consisting of a tube shape, a ribbon shape, and a fiber shape.
  • the sheet-forming agent may be at least one carbon-based nanomaterial selected from the group consisting of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, few-walled carbon nanotubes, branched carbon nanotubes, carbon nanoribbons, and carbon nanofibers; or at least one non-carbon-based nanomaterial selected from the group consisting of boron nitride nanotubes, boron nitride nanoribbons, and aramid nanofibers.
  • non-carbon-based nanomaterials are electrically insulating materials, when they are used as sheet-forming agents, a conductive additive must be added separately.
  • carbon-based nanomaterials when used as sheet-forming agents, the carbon-based nanomaterials themselves have good electrical conductivity, so a separate conductive additive does not need to be used, and various surface treatment techniques are possible, so they can be significantly advantageous compared to other sheet-forming agents.
  • the surface-forming agent in the present invention is not intended to control surface properties, so it may be used as is without any special surface treatment.
  • carbon nanotubes as the surface-forming agent
  • the surface-forming agent of the present invention may be carbon nanotubes in the form of lumps (particles) or bundles having a size of 0.2 to 200 microns. If the size of the particles or bundles is 0.2 microns or less, the size is too small, which causes a problem in that the surface-forming ability is significantly reduced, and if it is 200 microns or more, the particles are too large, which hinders surface formation, which is rather disadvantageous.
  • the carbon nanotubes may be particles or bundles having a size of 1 to 50 microns.
  • the carbon nanotubes are nanomaterials having an aspect ratio of 100 or more, and are at least one selected from the group consisting of carbon nanotubes such as single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, few-walled carbon nanotubes, and branched carbon nanotubes.
  • the binder includes a fiberizable fluorine-based resin and another binder resin to supplement the adhesiveness, which is a shortcoming of the fiberizable fluorine-based resin, and the form thereof may be two types: a first form which is a simple mixture of a fiberizable fluorine-based resin and another binder resin, or a second form which is a core-shell structure composite binder formed so that a core made of a fiberizable fluorine-based resin and a shell made of another binder resin surround the core.
  • the fluorine-based resin capable of fiberization may be polytetrafluoroethylene (PTFE), and as for other binder resins, basically all types of secondary battery binders may be used as long as they have adhesive properties that can be mixed with the fluorine-based resin particles.
  • PTFE polytetrafluoroethylene
  • the binder may be at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), carboxymethyl cellulose, styrene-butadiene copolymers, and acrylonitrile-butadiene copolymers; or a copolymer including at least one selected from the group consisting of acrylonitrile-based monomers, carboxyl-based monomers, and glycol-based monomers.
  • PVDF polyvinylidene fluoride
  • PAA polyacrylic acid
  • carboxymethyl cellulose carboxymethyl cellulose
  • styrene-butadiene copolymers styrene-butadiene copolymers
  • acrylonitrile-butadiene copolymers or a copolymer including at least one selected from the group consisting of acrylonitrile-based monomers, carboxyl-based monomers, and glycol-based monomers.
  • a simple mixture of a first type of binder, such as PTFE, a fluorine-based resin particle, and another binder resin having excellent adhesive properties can be manufactured using a simple dry blending method and a wet solution mixing method.
  • the dry blending method is a method of manufacturing a binder mixture or binder blend by simply mixing PTFE and another binder resin having excellent adhesive properties in a dry blender.
  • a mixed binder of the first type can be obtained using a simple dry blending device, since PTFE is a binder in the form of particles, there is a restriction that the other binder resin to be mixed with it must also be a binder resin in the form of particles having at least a similar or identical size, which makes manufacturing inconvenient.
  • the second type of binder a core-shell structure composite binder
  • a core-shell structure composite binder has a shell shape in which fluorine-based resin particles, i.e., PTFE, form a core inside, and another binder resin with adhesive properties surrounds the outer surface thereof.
  • fluorine-based resin particles inside provide planar forming ability during dry processing
  • the adhesive other binder resin on the surface complements the adhesiveness of the dry electrode, so that it can function as a binder having both planar forming ability and adhesiveness.
  • the fluorine-based resin forming the core is not limited as long as it contains a fluorine component and is a polymer capable of being fiberized, but in particular, it may be polytetrafluoroethylene (PTFE), and the particle diameter may be 0.05-5.0 microns. If the particle size of the fluorine-based resin is less than 0.05 microns, the particles are too small, making it difficult to form fluorine-based resin particles or to form a fluorine-based resin dispersion, which is disadvantageous. If it is 5 microns or more, the total surface area of the fluorine-based resin particles becomes small, so that the content of other adhesive binder resins coated on the surface becomes low, making it difficult to impart adhesiveness, which is rather disadvantageous.
  • PTFE polytetrafluoroethylene
  • the other binder resin forming the shell can be any polymer compound that has adhesive properties and can be used as a binder for secondary batteries.
  • the polymer that can be used as an electrode binder for a secondary battery can be a polymer that can be dissolved in organic or aqueous solvents, and can include one or more polymers. In one embodiment, it can be in the form of a homopolymer, such as polyvinylidene fluoride (PVDF), which is widely used as a binder for a positive electrode, or it can be a polymer in the form of a copolymer with various functions.
  • PVDF polyvinylidene fluoride
  • One or more of these binders can be mixed and used, which is advantageous because the characteristics of each binder are complemented to produce a better effect.
  • binder resins forming a representative shell may be, but are not limited to, one or more selected from the group consisting of a cellulose polymer binder such as polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), carboxymethyl cellulose, a flexible copolymer such as styrene-butadiene rubber or acrylonitrile-butadiene rubber, or a copolymer comprising one or more selected from the group consisting of acrylonitrile-based monomers, carboxyl-based monomers, and glycol-based monomers.
  • PVDF polyvinylidene fluoride
  • PAA polyacrylic acid
  • carboxymethyl cellulose a flexible copolymer
  • styrene-butadiene rubber or acrylonitrile-butadiene rubber or a copolymer comprising one or more selected from the group consisting of acrylonitrile-based monomers, carboxyl-based monomers, and glycol-based monomers.
  • a copolymer can be used, which is synthesized by copolymerizing a carboxylic monomer for imparting adhesiveness to another binder resin forming the shell and an acrylonitrile monomer for imparting stable electrochemical properties as a base, with a third monomer for imparting other functions.
  • a copolymer can be used, which is synthesized by copolymerizing a carboxylic monomer for imparting adhesiveness to another binder resin forming the shell and an acrylonitrile monomer for imparting stable electrochemical properties as a base, with a third monomer for imparting other functions.
  • a third monomer for imparting other functions.
  • an acrylate monomer neutralized with a compound consisting of 2-6 carbons is copolymerized together, these components cause geometric hindrance, which makes the synthesized copolymer flexible and has strong adhesiveness. If this is used to manufacture a composite binder with a core-shell structure, a composite binder that is flexible and has strong adhesiveness can be obtained
  • the carboxylic monomer may be one or more selected from the group consisting of acrylic acid, acrylate, maleic acid, and maleic anhydride, and in particular, the other binder resin forming the shell may be an acrylonitrile-ethylene glycol-maleic acid copolymer.
  • the core-shell structure composite binder of the above-described composition includes the steps of preparing a first binder dispersion by dispersing a fibrous fluorine-based resin in water; preparing a second binder solution by dissolving another binder resin having adhesive properties in a solvent; adding the second binder solution to the first binder dispersion while stirring; and a post-processing step of filtering, washing, and drying the resultant obtained after stirring is completed.
  • the step of preparing the first binder dispersion is performed by preparing an aqueous dispersion of fibrous fluorine-based resin particles, and a commercially available one may be used if necessary.
  • the step of preparing the second binder solution may be performed by dissolving another binder resin having adhesive properties in an organic solvent to prepare the second binder solution.
  • the organic solvent is not limited as long as it can dissolve another binder resin, but as an example, either DMF or NMP may be used.
  • the content of the fluorine-based resin dispersed in the first binder dispersion and the other binder resin dissolved in the second binder solution can be prepared to have a weight ratio of 90 to 10:10 to 90, and through this mixing ratio, a core-shell structured composite binder in the form of a single particle can be finally obtained, that is, a fluorine-based resin particle inside which is surrounded by a layer of another binder resin having good adhesiveness on its outer surface.
  • the stirring step can be performed by slowly adding the second binder solution to the first binder dispersion while stirring.
  • the stirring conditions have also been experimentally established and can be performed by vigorously stirring for 20 minutes to 5 hours at a temperature of 20 to 70°C at a speed of 200 to 10,000 rpm.
  • the post-processing step is a process for obtaining core-shell structure composite binder particles generated in the stirring step, and can be performed by filtering the result obtained after stirring is completed, separating the core-shell structure composite binder particles from the solvent, washing, purifying, and then drying. Here, filtering and washing can be performed more than once.
  • the content of the fibrous fluorine-based resin (fibrous fluorine-based resin) included in the binder may be 30 wt% or less of the total weight of the binder.
  • the fibrous fluorine-based resin constituting the binder may be replaced with another binder resin up to 80 wt%.
  • the binder included in the electrode composition for manufacturing a dry electrode is almost entirely composed of PTFE, and a pretreatment process was required to maintain the surface-forming ability of the dry electrode.
  • the electrode composition for manufacturing a dry electrode of the present invention includes a surface-forming agent, so that even if the content of the fibrous fluorine-based resin included in the binder is reduced to a maximum of 20 wt%, an excellent dry electrode surface can be formed directly through a calendaring process without a pretreatment process.
  • the electrode composition for manufacturing a dry electrode of the present invention may further include, if necessary, 1 to 100 parts by weight of one or more conductive nanomaterials selected from the group consisting of conductive carbon black, graphene, carbon nanoplates, or graphene nanoplates, per 100 parts by weight of the surface-forming agent.
  • one or more conductive nanomaterials selected from the group consisting of conductive carbon black, graphene, carbon nanoplates, or graphene nanoplates, per 100 parts by weight of the surface-forming agent.
  • a non-carbonaceous nanomaterial is used as the surface-forming agent, it is essential to further add a conductive nanomaterial to enhance conductivity.
  • the wound dry electrode rolls can be aged at an appropriate temperature.
  • Aging temperature is typically 30-80°C for 12-100 hours.
  • the aging temperature and time are inversely proportional; lower aging temperatures require longer aging times, while higher temperatures require shorter aging times. If the aging temperature or time exceeds the above ranges, the aging effect may be reduced or the dry electrode may be damaged, which is actually disadvantageous.
  • the dry electrode manufacturing device of the present invention comprises a stirring device for stirring and mixing an electrode composition for manufacturing a dry electrode, which comprises an active material, a binder, and a surface forming agent; a calender device for forming the stirred and mixed electrode composition into an electrode material layer sheet; and a rolling device for attaching and pressing the electrode material layer sheet by positioning it on at least one surface of a support film or a metal electrode plate.
  • the calender device and the rolling device may be installed so as to be positioned on the same line.
  • Electrode compositions 1 to 4 for manufacturing dry electrodes were prepared as follows. That is, the active material (NCM811), the surface-forming agent, and the binder were placed in a dry blender (powder mixer) in the mixing ratios shown in Table 1 and stirred at a speed of 2,000 rpm for 10 minutes to prepare electrode compositions 1 to 4 for manufacturing dry electrodes.
  • the surface-forming agent is a multi-walled carbon nanotube having a particle diameter of 20 microns, and the surface-forming agent was an as-received multi-walled carbon nanotube received from the manufacturer without separate pretreatment unless otherwise specified.
  • the binder (first form) was obtained by placing PTFE and PVDF or PTFE and PAEM in a dry blender (powder mixer) in the mixing ratios shown in Table 1 and mixing at a speed of 2,000 rpm for 10 minutes.
  • composition ratios are in weight %, and are PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), and PAEM (acrylonitrile-ethylene glycol-maleic acid copolymer).
  • Electrode compositions 5 to 11 for manufacturing dry electrodes were prepared by performing the same method as Example 1, except that a core-shell structure composite binder of the second type, not the first type, was manufactured as follows and the mixing ratio as shown in Table 2 was used.
  • NCM811 cotton forming agent Binder (Type 2) Core-shell structure composite binder 1 Core-shell structure composite binder 2 Core: PTFE Shell: PVDF Core: PTFE Shell:PAEM Example 5 95.0 2.0 0.6 2.4 Example 6 95.0 2.0 1.5 1.5 Example 7 95.0 2.0 0.6 2.4 Example 8 95.0 2.0 1.5 1.5 Example 9 95.5 2.5 1.0 1.0 Example 10 96.0 2.0 1.6 0.4 Example 11 95.0 1.5 1.5 1.5 1.5
  • Core-shell structure composite binders 1 and 2 were prepared as follows.
  • a first binder dispersion was prepared in which PTFE particles having an average particle diameter of 250 nanometers (0.25 microns) were dispersed in water.
  • a second binder solution was created by dissolving PVDF or PAEM, which is used as a positive electrode binder in existing lithium-ion batteries, in NMP.
  • the second binder solution was slowly added to the first binder dispersion and stirred at a speed of 3,500 rpm for 30 minutes.
  • the result obtained in the stirring step was filtered with a pressure filter, washed with distilled water twice, and then dried at 50 degrees Celsius to obtain light brown final reactants, core-shell structure composite binder 1 (core: PTFE + shell: PVDF) and core-shell structure composite binder 2 (core: PTFE + shell: PAEM).
  • An electrode composition 12 for manufacturing a dry electrode was prepared by performing the same method as Example 11, except that a core-shell structure composite binder 3 was manufactured by mixing PAEM and PVDF in a weight ratio of 1:1 instead of using only PAEM when manufacturing a second binder solution for manufacturing a core-shell structure composite binder.
  • An electrode composition 13 for manufacturing a dry electrode was obtained by performing the same method as Example 8, except that boron nitride nanotubes (BN Nanotube, NAIEEL Technology, Korea) were used as a surface forming agent.
  • boron nitride nanotubes BN Nanotube, NAIEEL Technology, Korea
  • An electrode composition 14 for manufacturing a dry electrode was obtained by performing the same method as Example 8, except that aramid nanofiber, which is a polymer nanofiber, was used as a surface forming agent.
  • An electrode composition 15 for manufacturing a dry electrode was obtained by performing the same method as Example 11, except that a coating layer was formed on the surface of the active material using 0.5 wt% of untreated multi-walled carbon nanotubes having a particle diameter of 20 microns and 1 wt% of untreated multi-walled carbon nanotubes having a particle diameter of 20 microns as a surface forming agent.
  • Comparative electrode compositions 1, 2, 4, and 6 to 7 were prepared using the same method as Example 1, except that the mixing ratios shown in Table 3 were used, and comparative electrode compositions 3 and 5 to 8 were prepared using the same method as Example 5. Since Comparative Examples 1 to 3 did not use a surface forming agent, 2 wt% of conductive carbon black was added.
  • the adhesive strength refers to the degree to which the electrode layer is transferred to the tape when it is attached and removed with Scotch tape. Weak: A lot is transferred, Strong: A little is transferred.
  • the electrode composition 5 has a better surface forming ability at 70°C than at 40°C.
  • the comparative electrode composition 8 also showed poor surface forming ability when calendered at room temperature, but it can be confirmed that the dry electrode surface is good when the calender roll temperature is increased to 100°C. From this, it can be seen that the temperature of the calender roll is one of the very important factors during calendering.
  • the surface forming ability of the electrode composition 5 for manufacturing a dry electrode obtained in Example 5 improved as the temperature of the calender roll increased from room temperature, 40°C, and 70°C during calendering
  • increasing the temperature of the calender roll during calendering is more effective in manufacturing a dry electrode surface, i.e., an electrode material layer sheet.
  • an electrode composition using 0.5 wt% of carbon nanotubes for the surface coating of an active material and 1.0 wt% as a surface forming agent as in Example 15 was calendered at a roll temperature of 100°C or lower, both the surface forming ability and the adhesive strength were good. From this result, it is shown that when a portion of the carbon nanotubes is used for the surface coating of an active material, the carbon nanotubes used for the surface coating of the active material also help in the surface forming of the dry electrode surface.
  • the adhesiveness including the degree to which the dry electrode is attached to the aluminum plate and the cohesion of each component within the dry electrode, was evaluated for the positive electrodes 1 to 7 manufactured in Examples 16 to 22.
  • an adhesive test was performed using Scotch tape (3M Scotch Tape). If the electrode layer was not completely peeled off from the plate when the tape was attached and then peeled off on the electrode layer, the adhesion of the electrode to the plate was judged to be good.
  • the cohesion between each component within the electrode was judged as “strong,” “average,” and “weak” based on the amount/slight amount of electrode layer material that was transferred to the tape when peeling the tape. This evaluation method is subjective and qualitative, but it is a method that can quickly evaluate adhesiveness.
  • positive electrodes 1 to 6 were well adhered without peeling off from the aluminum electrode plate.
  • the amount of electrode layer material transferred to the tape was small, which confirmed that it exhibited relatively good bonding strength.
  • positive electrode plate 7 was manufactured by attaching a dry electrode to an aluminum electrode plate on which a primer layer was preheated, and as a result of the tape test, the electrode layer was well attached with almost no peeling off, and the bonding strength of the dry electrode layer was confirmed to be better than that of positive electrode plates 1 to 6.
  • a dry electrode having more solid adhesive strength and bonding strength can be manufactured.
  • the electrical conductivity of the positive electrode plates 1 to 7 was confirmed by measuring the surface resistance (measuring device: Mitsubishi Corporation, 4-point probe method, measuring tip shape: flat), and the results are shown in Table 6.
  • Positive electrode plate 1 10 1 Positive electrode plate 2 10 1 Positive electrode plate 3 10 1 Positive electrode plate 4 10 1 Positive electrode plate 5 10 1 Positive electrode plate 6 10 1 Positive electrode plate 7 10 1
  • the surface resistance of the dry electrode surface was measured to be several tens of ohms/area, that is, 10 1 ohms/area, showing very good surface resistance.
  • positive electrode plate 6 which is an example in which some carbon nanotubes were first coated on the surface of the active material, it showed a lower surface resistance than the other positive electrode plates.
  • the charge/discharge cycle test was initially performed at rates of 0.1, 0.1, and 0.33C, followed by a charge/discharge life test at a rate of 1.0C.
  • the discharge capacity after 4 cycles was considered the initial capacity, and the capacity retention rate (%) was calculated by comparing these initial capacities with the discharge capacity after 50 cycles.
  • the initial capacity was 186 mAh/g, and after 50 cycles, the capacity was 173 mAh/g, showing a capacity retention rate of approximately 93%, confirming excellent characteristics.
  • the charge/discharge life test results of the remaining coin cells all showed an initial capacity of 183-187 mAh/g, a discharge capacity after 50 cycles of 170-174 mAh/g, and a capacity retention rate of 91-95%.
  • the capacity retention rate was as high as approximately 96% for the positive electrode plate 6 and coin cell 6 manufactured with an active material obtained by pre-coating some of the carbon nanotubes on the surface of the active material. This is thought to be because the surface resistance of the positive electrode plate 6 including the carbon nanotubes, which have good electrical conductivity, is lower than that of the other positive electrode plates because they are uniformly coated on the surface of the active material.
  • the present invention improves the planarizing ability of the dry electrode to the extent that the calendering process can be performed directly without performing the kneading process and the pulverizing process, which are pretreatment steps for fiberization, on the prepared electrode composition by replacing the PTFE, a fiberizing polymer that had to be used at 100 wt% in the prior art, with another binder.
  • PTFE is contained in an amount of 15 wt% or more of the total weight of the binder, room temperature calendering is sufficiently effective, but when the PTFE content is low, less than 15 wt%, it was confirmed that high temperature calendering using a method of applying pressure while heating the calender roll is more effective.
  • carbon-based nanomaterials including carbon nanotubes are nanomaterials with high electrical conductivity, so when carbon-based nanomaterials, especially carbon nanotubes, are used as a surface forming agent, the electrical conductivity of the dry electrode is excellent without using a separate conductive additive, so it can be much more effective than other types of surface forming agents.
  • the electrode composition for manufacturing a dry electrode of the present invention it is more effective to use a binder made in the form of a composite binder with a core-shell structure rather than a method of simply dry blending different binders in the other adhesive binder resin used in parallel with PTFE, as this can expand the range of PTFE substitution.
  • the present invention has been described using two types of binders, including polyvinylidene fluoride and acrylonitrile-ethylene glycol-maleic acid copolymer, as adhesive binders.
  • binders including polyvinylidene fluoride and acrylonitrile-ethylene glycol-maleic acid copolymer
  • the scope of the present invention is not limited to the two binders, and it is clear that the better the adhesiveness of a binder, the more effective it is.

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Abstract

Une technologie de la présente invention concerne une électrode sèche, qui est une électrode fabriquée à l'aide d'un procédé sec, et, plus particulièrement : une composition d'électrode pour la fabrication d'une électrode sèche, la composition étant une nouvelle composition capable de simplifier un procédé de fabrication et de fournir une électrode sèche de meilleure qualité en omettant un procédé qui est essentiel dans l'état de la technique afin de fabriquer une électrode sans solvant à l'aide d'un procédé sec ; une électrode sèche formée à l'aide de la composition d'électrode ; une batterie secondaire comprenant l'électrode sèche ; et un procédé et un dispositif de fabrication d'électrode sèche utilisant la composition d'électrode.
PCT/KR2025/099697 2024-03-13 2025-03-12 Composition d'électrode pour la fabrication d'électrode sèche, électrode sèche formée à l'aide d'une composition d'électrode, batterie secondaire comprenant une électrode sèche, et procédé et dispositif de fabrication d'électrode sèche utilisant une composition d'électrode Pending WO2025193055A1 (fr)

Applications Claiming Priority (4)

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KR10-2024-0035133 2024-03-13
KR20240035133 2024-03-13
KR10-2024-0075451 2024-06-11
KR1020240075451A KR20250138611A (ko) 2024-03-13 2024-06-11 건식전극제조용 전극조성물, 상기 전극조성물로 형성된 건식전극, 상기 건식전극을 포함하는 이차전지, 상기 전극조성물을 이용한 건식전극 제조방법 및 장치

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100201056B1 (ko) * 1994-10-19 1999-06-15 이노우에 노리유끼 전지용 결착제 및 이를 사용한 전극용 조성물 및 전지
US20180175366A1 (en) * 2015-06-26 2018-06-21 Florida State University Research Foundation, Inc. Dry process method for producing electrodes for electrochemical devices and electrodes for electrochemical devices
KR20180121411A (ko) * 2017-04-28 2018-11-07 주식회사 엘지화학 양극, 이를 포함하는 이차 전지, 및 상기 양극의 제조 방법
KR20220076344A (ko) * 2020-11-30 2022-06-08 주식회사 엘지에너지솔루션 이차전지용 양극 활물질, 이의 제조방법, 이를 포함하는 프리스탠딩 필름, 건식 양극 및 건식양극을 포함하는 이차전지
KR20230015109A (ko) * 2021-07-22 2023-01-31 주식회사 엘지에너지솔루션 이차 전지용 전극 및 이를 포함하는 이차 전지

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100201056B1 (ko) * 1994-10-19 1999-06-15 이노우에 노리유끼 전지용 결착제 및 이를 사용한 전극용 조성물 및 전지
US20180175366A1 (en) * 2015-06-26 2018-06-21 Florida State University Research Foundation, Inc. Dry process method for producing electrodes for electrochemical devices and electrodes for electrochemical devices
KR20180121411A (ko) * 2017-04-28 2018-11-07 주식회사 엘지화학 양극, 이를 포함하는 이차 전지, 및 상기 양극의 제조 방법
KR20220076344A (ko) * 2020-11-30 2022-06-08 주식회사 엘지에너지솔루션 이차전지용 양극 활물질, 이의 제조방법, 이를 포함하는 프리스탠딩 필름, 건식 양극 및 건식양극을 포함하는 이차전지
KR20230015109A (ko) * 2021-07-22 2023-01-31 주식회사 엘지에너지솔루션 이차 전지용 전극 및 이를 포함하는 이차 전지

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