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WO2025178012A1 - Séparateur pour batterie secondaire non aqueuse et batterie secondaire non aqueuse - Google Patents

Séparateur pour batterie secondaire non aqueuse et batterie secondaire non aqueuse

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Publication number
WO2025178012A1
WO2025178012A1 PCT/JP2025/005339 JP2025005339W WO2025178012A1 WO 2025178012 A1 WO2025178012 A1 WO 2025178012A1 JP 2025005339 W JP2025005339 W JP 2025005339W WO 2025178012 A1 WO2025178012 A1 WO 2025178012A1
Authority
WO
WIPO (PCT)
Prior art keywords
meth
separator
mol
secondary battery
resin
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/JP2025/005339
Other languages
English (en)
Japanese (ja)
Inventor
愛 小金丸
聡 西川
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.)
Teijin Ltd
Original Assignee
Teijin 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
Application filed by Teijin Ltd filed Critical Teijin Ltd
Publication of WO2025178012A1 publication Critical patent/WO2025178012A1/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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42—Acrylic resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • 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

  • This disclosure relates to a separator for a non-aqueous secondary battery and a non-aqueous secondary battery.
  • Organofluorine compounds have useful properties such as heat resistance, chemical resistance, and surface activity, and have been used in a wide range of manufacturing and industrial applications. In recent years, reports have been released about the ecotoxicity and human toxicity of organofluorine compounds, leading to stricter restrictions on the production and use of these compounds worldwide.
  • the adhesive porous layer preferably has a network structure containing the acrylic resin (1).
  • the network structure of the adhesive porous layer means a structure in which the resin is continuously connected in a network shape and has a large number of pores.
  • the network structure of the adhesive porous layer may be a planar network structure in the surface direction of the separator, or a three-dimensional network structure in the surface direction and thickness direction of the separator.
  • the three-dimensional mesh structure of the adhesive porous layer may be flattened by the heat press used to bond the separator to the electrode, and part or all of the separator may have a planar mesh structure when bonded to the electrode.
  • R1 is a hydrogen atom or a methyl group
  • R2 and R3 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
  • the alkyl group may be linear, branched, or cyclic.
  • R2 and R3 are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
  • the (meth)acrylamide monomer is preferably at least one selected from the group consisting of acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N,N-dimethylacrylamide, and N,N-dimethylmethacrylamide.
  • the total proportion of (meth)acrylic acid and (meth)acrylamide monomers in all polymerization components of the acrylic resin (1) is 20 mol% or more, preferably 20 mol% to 90 mol%, more preferably 20 mol% to 70 mol%, even more preferably 20 mol% to 50 mol%, still more preferably 25 mol% to 45 mol%, still more preferably 30 mol% to 40 mol%, and particularly preferably 35 mol% to 40 mol%.
  • the proportion of (meth)acrylic acid in all polymerization components of the acrylic resin (1) is preferably 10 mol% to 50 mol%, more preferably 15 mol% to 40 mol%, still more preferably 20 mol% to 30 mol%, and particularly preferably 20 mol% to 25 mol%.
  • the proportion of the (meth)acrylamide monomer in all polymerization components of the acrylic resin (1) is preferably 10 mol% to 40 mol%, more preferably 10 mol% to 30 mol%, still more preferably 10 mol% to 25 mol%, and particularly preferably 15 mol% to 20 mol%.
  • the molar ratio of (meth)acrylic acid to (meth)acrylamide monomer, which are the polymerization components of acrylic resin (1), is 40:60 to 60:40, preferably 45:55 to 60:40, and more preferably 50:50 to 60:40.
  • the total proportion of methyl (meth)acrylate and butyl (meth)acrylate in all polymerization components of the acrylic resin (1) is preferably 10 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, and even more preferably 50 mol% to 65 mol%.
  • the proportion of methyl (meth)acrylate in all polymer components of the acrylic resin (1) is preferably 10 mol % to 65 mol %, more preferably 25 mol % to 60 mol %, and even more preferably 40 mol % to 55 mol %.
  • the proportion of butyl (meth)acrylate in all polymer components of the acrylic resin (1) is preferably 5 mol % to 25 mol %, more preferably 10 mol % to 20 mol %, and even more preferably 10 mol % to 15 mol %.
  • the butyl (meth)acrylate is at least one selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, and t-butyl methacrylate, and is preferably at least one of n-butyl acrylate and n-butyl methacrylate.
  • Examples of such monomers include lower alkyl (meth)acrylate esters (having an alkyl group containing 8 or fewer carbon atoms) other than methyl (meth)acrylate and butyl (meth)acrylate.
  • Examples of such lower alkyl (meth)acrylate esters include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, n-heptyl (meth)acrylate, isoheptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.
  • Examples of such monomers include styrene-based monomers.
  • Examples of styrene-based monomers include styrene, ⁇ -methylstyrene, and alkyl-substituted styrenes such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene.
  • Preferred styrene-based monomers are styrene and ⁇ -methylstyrene, with styrene being more preferred.
  • Examples of such monomers include vinyl nitrile compounds.
  • Examples of vinyl nitrile compounds include acrylonitrile and methacrylonitrile.
  • the adhesive porous layer contains substantially no fluorine-containing resin.
  • fluorine-containing resins include polyvinylidene fluoride resins and fluorine-containing rubbers.
  • polyvinylidene fluoride resins include homopolymers of vinylidene fluoride (i.e., polyvinylidene fluoride); copolymers of vinylidene fluoride and halogen-containing monomers such as hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, vinyl fluoride, and trichloroethylene; copolymers of vinylidene fluoride and monomers other than halogen-containing monomers; copolymers of vinylidene fluoride, halogen-containing monomers, and monomers other than halogen-containing monomers; and mixtures thereof.
  • the adhesive porous layer being substantially free of fluorine-containing resin means that the mass ratio of the fluorine-containing resin in the adhesive porous layer is 1 mass % or less.
  • the mass proportion of the fluorine-containing resin in the adhesive porous layer is preferably as small as possible, and is preferably 0.5 mass% or less, more preferably 0.1 mass% or less, and particularly preferably 0 mass%. In other words, it is particularly preferable that the adhesive porous layer does not contain a fluorine-containing resin.
  • the adhesive porous layer may further contain particles, which may include inorganic particles and/or organic particles.
  • inorganic particles examples include metal oxide particles, metal hydroxide particles, metal sulfate particles, metal carbonate particles, metal nitride particles, and clay mineral particles.
  • metal oxides constituting the metal oxide particles include silica (silicon dioxide), alumina (aluminum oxide), boehmite (alumina monohydrate), titania (titanium oxide), zirconia (zirconium oxide), magnesium oxide, and barium oxide, with alumina being preferred.
  • metal hydroxides constituting the metal hydroxide particles include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, chromium hydroxide, zirconium hydroxide, cerium hydroxide, nickel hydroxide, and boron hydroxide, with magnesium hydroxide being preferred.
  • the inorganic particles may be surface-modified with a silane coupling agent or the like.
  • At least one type of inorganic particle selected from the group consisting of metal oxide particles, metal hydroxide particles, and metal sulfate particles is preferred.
  • at least one type selected from the group consisting of alumina particles (aluminum oxide particles), magnesium hydroxide particles, and barium sulfate particles is more preferred.
  • metal sulfate particles are preferred, and barium sulfate particles are more preferred, from the viewpoint that they are less likely to decompose the electrolytic solution or electrolyte and therefore less likely to cause gas generation inside the battery.
  • the particle shape of the inorganic particles there are no limitations on the particle shape of the inorganic particles, and they may be spherical, elliptical, plate-like, needle-like, or irregular. From the perspective of suppressing internal short circuits in the battery, it is preferable that the inorganic particles contained in the adhesive porous layer be plate-like particles or non-agglomerated primary particles.
  • the average primary particle size of the inorganic particles contained in the adhesive porous layer is preferably 0.01 ⁇ m to 2 ⁇ m, more preferably 0.05 ⁇ m to 1 ⁇ m, and even more preferably 0.1 ⁇ m to 0.5 ⁇ m.
  • the average primary particle size of the inorganic particles is 0.01 ⁇ m or more, a porous structure is easily formed in the adhesive porous layer, and the adhesive porous layer has excellent electrolyte permeability and ion permeability. From this viewpoint, the average primary particle size of the inorganic particles is more preferably 0.05 ⁇ m or more, and even more preferably 0.1 ⁇ m or more.
  • the adhesive porous layer is easily adhered to the electrode and is not easily peeled off from the electrode.
  • the average primary particle size of the inorganic particles is more preferably 1 ⁇ m or less, and even more preferably 0.5 ⁇ m or less.
  • the average primary particle size of inorganic particles is determined by measuring the long diameter of 100 randomly selected inorganic particles during observation with a scanning electron microscope (SEM) and averaging the long diameters of the 100 particles.
  • the sample used for SEM observation is inorganic particles that are the material forming the adhesive porous layer, or inorganic particles extracted from the adhesive porous layer. There are no restrictions on the method for extracting inorganic particles from the adhesive porous layer.
  • Examples of such methods include immersing the adhesive porous layer peeled off from the separator in an organic solvent that dissolves the binder resin, thereby dissolving the binder resin with the organic solvent and extracting the inorganic particles; or heating the adhesive porous layer peeled off from the separator to approximately 800°C to eliminate the binder resin and extract the inorganic particles.
  • the volume ratio of the inorganic particles to the acrylic resin (1) and inorganic particles contained in the adhesive porous layer is preferably 5% to 50% by volume, more preferably 10% to 40% by volume, and even more preferably 15% to 30% by volume, from the viewpoint of achieving a good balance between the adhesiveness of the separator to the electrode and the thermal dimensional stability of the separator.
  • the adhesive porous layer may contain organic particles, such as particles made of crosslinked polymers such as crosslinked poly(meth)acrylic acid, crosslinked poly(meth)acrylic acid ester, crosslinked polysilicone, crosslinked polystyrene, crosslinked polydivinylbenzene, crosslinked styrene-divinylbenzene copolymer, melamine resin, phenol resin, and benzoguanamine-formaldehyde condensate; and particles made of heat-resistant polymers such as polysulfone, polyacrylonitrile, aramid, and polyacetal.
  • crosslinked polymers such as crosslinked poly(meth)acrylic acid, crosslinked poly(meth)acrylic acid ester, crosslinked polysilicone, crosslinked polystyrene, crosslinked polydivinylbenzene, crosslinked styrene-divinylbenzene copolymer, melamine resin, phenol resin, and benzoguanamine-formaldehyde
  • One type of organic particle may be used alone, or two or more types may be used in combination.
  • An adhesive porous layer that contains substantially no organic particles means that the volume ratio of organic particles to the acrylic resin (1) and organic particles contained in the adhesive porous layer is less than 5 volume %. In this embodiment, the volume ratio of organic particles to the acrylic resin (1) and organic particles contained in the adhesive porous layer is 0 volume % or more and less than 5 volume %.
  • the adhesive porous layer may contain additives such as a dispersant such as a surfactant, a wetting agent, an antifoaming agent, and a pH adjuster.
  • a dispersant such as a surfactant, a wetting agent, an antifoaming agent, and a pH adjuster.
  • the dispersant is added, for example, to the coating liquid for forming the adhesive porous layer for the purpose of improving dispersibility, coatability, or storage stability.
  • the wetting agent, antifoaming agent, and pH adjuster are added, for example, to the coating liquid for forming the adhesive porous layer for the purpose of improving compatibility with the porous substrate, preventing air entrapment in the coating liquid, or adjusting the pH.
  • the mass per unit area of the adhesive porous layer is preferably 0.3 g/m 2 to 2 g/m 2 per side of the separator, more preferably 0.4 g/m 2 to 1.5 g/m 2 , and even more preferably 0.5 g/m 2 to 1 g/m 2 , from the viewpoint of achieving a good balance between adhesion to the electrode, permeability of the electrolyte solution, and ion permeability .
  • the mass per unit area of the adhesive porous layers, in total for both sides is preferably 0.6 g/m 2 to 4 g/m 2 , more preferably 0.8 g/m 2 to 3 g/m 2 , and even more preferably 1 g/m 2 to 2 g/m 2 .
  • the mass per unit area of the adhesive porous layer is calculated by cutting a 20cm x 20cm piece of separator, peeling off the adhesive porous layer, measuring the mass, and dividing the mass by the area.
  • the thickness of the separator is preferably 5 ⁇ m or more, more preferably 7 ⁇ m or more, and even more preferably 9 ⁇ m or more. From the viewpoint of the energy density of the battery, the thickness of the separator is preferably 15 ⁇ m or less, more preferably 12 ⁇ m or less, and even more preferably 10 ⁇ m or less. The thickness of the separator is determined by measuring 20 points within a 10 cm square area with a contact type thickness meter and averaging the measurements.
  • the air permeability of the separator is preferably 100 seconds/100 mL or more, more preferably 110 seconds/100 mL or more, and even more preferably 120 seconds/100 mL or more. From the viewpoint of ion permeability, the air permeability of the separator is preferably 1000 seconds/100 mL or less, more preferably 700 seconds/100 mL or less, and even more preferably 500 seconds/100 mL or less.
  • the air permeability of the separator is measured using a digital Oken air permeability tester in accordance with JIS P8117:2009.
  • the porosity of the separator is preferably 30% to 60% from the viewpoint of ion permeability.
  • the porosity ⁇ (%) of the separator is calculated by the following formula.
  • the mass per unit area of each constituent material is W1 , W2 , W3 , ..., Wn (g/ cm2 )
  • the true density of each constituent material is d1 , d2 , d3 , ..., dn (g/ cm3 )
  • the thickness of the separator is t (cm).
  • Wet coating methods include, for example, a step of applying a coating liquid to one or both sides of a porous substrate to form a coating layer; a step of immersing the porous substrate with the coating layer in a coagulating liquid to solidify the coating layer and form a porous layer; and a step of removing the laminate consisting of the porous substrate and porous layer from the coagulating liquid, washing with water, and drying.
  • the solvent used to prepare the coating liquid includes a solvent that dissolves the acrylic resin (1) (hereinafter also referred to as a "good solvent”).
  • good solvents include polar amide solvents such as N-methylpyrrolidone, dimethylacetamide, and dimethylformamide.
  • the solvent used to prepare the coating liquid may contain a phase separation agent that induces phase separation, in order to form a porous layer with a good porous structure. Therefore, the solvent used to prepare the coating liquid may be a mixed solvent of a good solvent and a phase separation agent. It is preferable to mix the phase separation agent with the good solvent in an amount that ensures a viscosity appropriate for coating. Examples of phase separation agents include water, butanediol, and ethylene glycol.
  • the solvent used to prepare the coating liquid is a mixed solvent of a good solvent and a phase separation agent, from the perspective of forming a good porous structure, a mixed solvent containing 60% by mass or more of the good solvent and 5% to 40% by mass of the phase separation agent is preferred.
  • the resin concentration of the coating liquid is preferably 1% to 20% by mass in order to form a good porous structure. If the porous layer contains inorganic particles, the inorganic particle concentration of the coating liquid is preferably 0.5% to 50% by mass in order to form a good porous structure.
  • the separator of the present disclosure can also be manufactured using a dry coating method.
  • the dry coating method involves applying a coating liquid to a porous substrate, drying the coating layer, and volatilizing and removing the solvent, thereby forming a porous layer on the porous substrate.
  • the nonaqueous secondary battery of the present disclosure is less likely to separate from the electrodes. Therefore, the nonaqueous secondary battery of the present disclosure is less likely to develop internal short circuits.
  • Examples of the conductive additive include carbon materials such as acetylene black, ketjen black, graphite powder, etc.
  • Examples of the current collector include aluminum foil, titanium foil, stainless steel foil, etc., each having a thickness of 5 ⁇ m to 20 ⁇ m.
  • the electrolyte solution is preferably a solution in which a lithium salt is dissolved in a non-aqueous solvent.
  • lithium salts include LiPF 6 , LiBF 4 , and LiClO 4 .
  • non-aqueous solvents include cyclic carbonates such as ethylene carbonate, propylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, and vinylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and fluorine-substituted derivatives thereof; and cyclic esters such as ⁇ -butyrolactone and ⁇ -valerolactone. These may be used alone or in combination.
  • the electrode was cut into a rectangle measuring 15 mm wide x 70 mm long.
  • the separator was cut into a rectangle measuring 18 mm TD x 74 mm MD.
  • Release paper measuring 15 mm wide x 70 mm long was prepared.
  • the separator was layered on the active material layer of the electrode, and then the release paper was layered on top of the separator to create a laminate.
  • the laminate was inserted into an aluminum laminate film pack, and an electrolyte solution (1 mol/L LiPF 6 -ethylene carbonate:ethyl methyl carbonate [mass ratio 3:7]) was poured into the laminate, allowing the electrolyte solution to soak into the laminate.
  • the pack and the laminate were heat-pressed in the stacking direction using a heat press machine (wet heat press) to bond the electrodes and separators.
  • the heat press conditions were a temperature of 85°C, a pressure of 1 MPa, and a time of 5 minutes. After heat pressing, the laminate was removed from the pack, and the release paper was peeled off to obtain a wet adhesive test piece.
  • the uncoated side of the test specimen's electrode was fixed to a metal plate with double-sided tape, and the metal plate was fixed to the lower chuck of a Tensilon (A&D Corporation, STB-1225S).
  • the metal plate was fixed to the Tensilon so that the longitudinal direction of the test specimen (i.e., the separator's MD) was aligned with the direction of gravity.
  • the separator was peeled away from the electrode by approximately 2 cm from the bottom edge, and this edge was fixed to the upper chuck, and a 180° peel test was performed.
  • the tensile speed for the 180° peel test was 20 mm/min, and loads (N) were collected at 0.4 mm intervals from 10 mm to 40 mm after the start of measurement, and the average was calculated.
  • the loads for 10 test specimens were then averaged to determine the adhesive strength (N/15 mm) between the electrode and separator.
  • a positive electrode slurry was prepared by mixing 89.5 parts by mass of lithium cobalt oxide powder as a positive electrode active material, 4.5 parts by mass of acetylene black as a conductive additive, 6 parts by mass of polyvinylidene fluoride as a binder resin, and an appropriate amount of N-methyl-2-pyrrolidone using a twin-arm mixer.
  • the positive electrode slurry was applied to both sides of a 20 ⁇ m-thick aluminum foil, dried, and pressed to obtain a positive electrode having positive electrode active material layers on both sides.
  • a negative electrode slurry was prepared by mixing 300 parts by mass of artificial graphite as a negative electrode active material, 7.5 parts by mass of an aqueous dispersion containing 40% by mass of a modified styrene-butadiene copolymer as a binder resin, 3 parts by mass of carboxymethyl cellulose as a thickener, and an appropriate amount of water with a twin-arm mixer.
  • the negative electrode slurry was applied to both sides of a 10 ⁇ m thick copper foil, dried, and pressed to obtain a negative electrode having a negative electrode active material layer on both sides.
  • Example 2 The acrylic resin (1) was dissolved in dimethylacetamide (DMAc), and barium sulfate particles were further stirred and dispersed to prepare a coating solution (2).
  • the coating solution (2) had an acrylic resin (1) concentration of 8.0 mass%, and the acrylic resin (1):barium sulfate particles ratio was 80:20 [volume ratio].
  • the acrylic resin (1) used in Example 2 was the same as the acrylic resin (1) used in Example 1.
  • Example 3 A separator was prepared in the same manner as in Example 1, except that the acrylic resin (1) was changed to an acrylic resin (1) having the monomer composition shown in Table 1. A nonaqueous secondary battery was prepared using this separator.
  • Example 4 A separator was prepared in the same manner as in Example 2, except that the acrylic resin (1) was changed to an acrylic resin (1) having the monomer composition shown in Table 1. A nonaqueous secondary battery was prepared using this separator. The acrylic resin (1) used in Example 4 was the same as the acrylic resin (1) used in Example 3.
  • Example 1 A separator was produced in the same manner as in Example 2, except that the acrylic resin (1) was changed to a polyvinylidene fluoride resin (a binary copolymer of vinylidene fluoride and hexafluoropropylene, weight-average molecular weight 1,400,000, and hexafluoropropylene 1.5 mol%).
  • a polyvinylidene fluoride resin a binary copolymer of vinylidene fluoride and hexafluoropropylene, weight-average molecular weight 1,400,000, and hexafluoropropylene 1.5 mol%.
  • the adhesive porous layer was coated so that the separator had a thickness of 9 ⁇ m.
  • the mass of the adhesive porous layer shown in Table 1 is the total mass of both sides of the separator.
  • the mass of the adhesive porous layer per separator side in each example and comparative example is half the mass of the adhesive porous layer shown in Table 1.
  • Mw Weight average molecular weight
  • DMAc Dimethylacetamide
  • VDF-HFP Dipolymer of vinylidene fluoride and hexafluoropropylene
  • PMMA Polymethyl methacrylate resin
  • MAA Methacrylic acid
  • NMMAm N-methylmethacrylamide
  • DMMAm N,N-dimethylmethacrylamide
  • MMA Methyl methacrylate
  • BA n-butyl acrylate

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Cell Separators (AREA)

Abstract

Ce séparateur pour une batterie secondaire non aqueuse comprend : un matériau de base poreux ; et une couche poreuse adhésive qui est disposée sur une ou les deux surfaces du matériau de base poreux et qui contient une résine acrylique (1). La résine acrylique (1) contient, en tant que composants de polymérisation, un acide (méth)acrylique, un monomère à base de (méth)acrylamide, et du (méth)acrylate de méthyle et/ou du (méth)acrylate de butyle. La proportion totale de l'acide (méth)acrylique et du monomère à base de (méth)acrylamide dans tous les composants de polymérisation est de 20 % en moles ou plus, et le rapport molaire entre l'acide (méth)acrylique et le monomère à base de (méth)acrylamide est de 40 : 60 à 60 : 40.
PCT/JP2025/005339 2024-02-19 2025-02-18 Séparateur pour batterie secondaire non aqueuse et batterie secondaire non aqueuse Pending WO2025178012A1 (fr)

Applications Claiming Priority (2)

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JP2024-023072 2024-02-19
JP2024023072A JP2025126702A (ja) 2024-02-19 2024-02-19 非水系二次電池用セパレータ及び非水系二次電池

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WO2025178012A1 true WO2025178012A1 (fr) 2025-08-28

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JP (1) JP2025126702A (fr)
WO (1) WO2025178012A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012119225A (ja) * 2010-12-02 2012-06-21 Teijin Ltd 非水電解質電池用セパレータ及び非水電解質電池
WO2023123220A1 (fr) * 2021-12-30 2023-07-06 宁德时代新能源科技股份有限公司 Séparateur, batterie secondaire le comprenant, module de batterie, bloc-batterie et appareil
WO2023179248A1 (fr) * 2022-03-25 2023-09-28 宁德时代新能源科技股份有限公司 Séparateur et son procédé de préparation, batterie, et dispositif électrique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012119225A (ja) * 2010-12-02 2012-06-21 Teijin Ltd 非水電解質電池用セパレータ及び非水電解質電池
WO2023123220A1 (fr) * 2021-12-30 2023-07-06 宁德时代新能源科技股份有限公司 Séparateur, batterie secondaire le comprenant, module de batterie, bloc-batterie et appareil
WO2023179248A1 (fr) * 2022-03-25 2023-09-28 宁德时代新能源科技股份有限公司 Séparateur et son procédé de préparation, batterie, et dispositif électrique

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