WO2015076574A1 - Séparateur et batterie rechargeable l'utilisant - Google Patents

Séparateur et batterie rechargeable l'utilisant Download PDF

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Publication number
WO2015076574A1
WO2015076574A1 PCT/KR2014/011179 KR2014011179W WO2015076574A1 WO 2015076574 A1 WO2015076574 A1 WO 2015076574A1 KR 2014011179 W KR2014011179 W KR 2014011179W WO 2015076574 A1 WO2015076574 A1 WO 2015076574A1
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Prior art keywords
separator
adhesive layer
meth
polyvinylidene fluoride
acrylate
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PCT/KR2014/011179
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English (en)
Korean (ko)
Inventor
이경주
김남효
김양섭
윤효상
최종섭
Original Assignee
삼성에스디아이 주식회사
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Priority claimed from KR1020140133340A external-priority patent/KR20150106810A/ko
Application filed by 삼성에스디아이 주식회사 filed Critical 삼성에스디아이 주식회사
Publication of WO2015076574A1 publication Critical patent/WO2015076574A1/fr

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    • 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
    • H01M50/426—Fluorocarbon polymers
    • 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
    • H01M50/449—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
    • H01M50/457—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
    • 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
    • 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
    • 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
    • H01M50/494—Tensile strength
    • 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 separator and a secondary battery using the same.
  • a nickel-cadnium battery, a nickel-hydrogen battery, a nickel-zinc battery, a lithium secondary battery, etc. are used, for example.
  • lithium secondary batteries have been used in many fields because of their advantages such as small size and large size, high operating voltage, and high energy density per unit weight.
  • the separator wound between the electrode and the electrode is easily separated, so that the adhesion between the separator and the electrode is increased.
  • it is required to have excellent shape stability of the secondary battery so as to prevent the shape from changing, such as distorting the battery due to continuous charging and discharging.
  • it is known to form an organic / inorganic mixed coating layer on one or both sides of the base film of the separator in order to improve the adhesion between the separator and the electrode and the heat resistance of the separator (Korean Patent No. 10-0775310). It cannot be sufficiently secured, so it is difficult to apply to batches of various sizes and shapes.
  • a secondary battery including a separator having an adhesive force applicable to a large-area secondary battery and capable of maintaining morphological stability and adhesion of the battery even after charging and discharging, which is an environment in which an actual battery is used.
  • An object of the present invention is to provide a separator and an improved secondary battery using the same.
  • an acrylic copolymer comprising a porous substrate and repeating units derived from (meth) acrylate monomers formed on one or both surfaces of the porous substrate, and a polyamide having a weight average molecular weight of 1,000,000 g / mol or more
  • a separator comprising a vinylidene fluoride polymer containing adhesive layer.
  • a separator comprising a porous substrate and a binder-containing adhesive layer formed on one or both sides of the porous substrate, the charge or discharge of the separator 1 after the charge and discharge of formula 1 to transfer the separator to the separator Separators are provided, the rates being at least 50% each.
  • a 0 is the total area of the cathode or anode
  • a 1 forms an electrode assembly in which the positive electrode, the separator, and the negative electrode are sequentially stacked, and at the temperature of 20 ° C. to 110 ° C. for 1 second to 5 seconds, with a force of 1 kgf / cm 2 to 30 kgf / cm 2 .
  • the electrolyte solution is injected into the compressed electrode assembly, and the second electrode is pressed with a force of 1 kgf / cm 2 to 30 kgf / cm 2 for 60 ° C. to 110 ° C., 30 seconds to 180 seconds, and then charged, discharged and charged.
  • the area of the positive electrode or negative electrode active material transferred to the separator.
  • a secondary battery particularly a lithium secondary battery, including the separator according to the above example is provided.
  • Separation membrane according to an embodiment of the present invention has the effect that the shape stability of the battery after the charge and discharge of the battery and the adhesion to the electrode is enhanced.
  • the separator according to the present invention can maintain high efficiency charge and discharge characteristics due to improved shape stability.
  • FIG. 1 is an exploded perspective view of a rechargeable battery according to an exemplary embodiment.
  • FIG. 2 is an exploded perspective view of a secondary battery according to another embodiment.
  • an acrylic copolymer comprising a porous substrate and repeating units derived from (meth) acrylate monomers formed on one or both surfaces of the porous substrate and polyvinylidene having a weight average molecular weight of 1,000,000 g / mol or more.
  • a separator is provided that includes a fluoride-based polymer-containing adhesive layer.
  • the porous substrate may use a porous substrate having a plurality of pores and can be used in an electrochemical device.
  • Porous substrates include, but are not limited to, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polyimide, polycarbonate, polyetheretherketone, polyaryletherketone, polyetherimide , Polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, and any one polymer selected from the group consisting of polyethylene naphthalene or a polymer membrane formed of a mixture of two or more thereof Can be.
  • the porous substrate may be a polyolefin-based substrate, the polyolefin-based substrate is excellent in the shutdown (shut down) function may contribute to the improvement of the safety of the battery.
  • the polyolefin-based substrate may be selected from the group consisting of, for example, polyethylene monolayer, polypropylene monolayer, polyethylene / polypropylene double membrane, polypropylene / polyethylene / polypropylene triple membrane, and polyethylene / polypropylene / polyethylene triple membrane.
  • the polyolefin resin may include a non-olefin resin in addition to the olefin resin, or may include a copolymer of an olefin and a non-olefin monomer.
  • the porous substrate may have a thickness of 1 ⁇ m to 40 ⁇ m, more specifically 5 to 15 ⁇ m.
  • a separator having a suitable thickness, thick enough to prevent a short circuit between the positive and negative electrodes of the battery, but not thick enough to increase the internal resistance of the battery.
  • the adhesive layer may be formed of an adhesive layer composition
  • the adhesive layer composition may include an acrylic copolymer including a (meth) acrylate monomer-derived repeating unit, a polyvinylidene fluoride polymer and a solvent having a weight average molecular weight of 1,000,000 g / mol or more. It may include.
  • the adhesive layer composition may further include inorganic particles.
  • an acrylic copolymer including a (meth) acrylate monomer-derived repeating unit as a binder of the adhesive layer and a weight average molecular weight By using the polyvinylidene fluoride-based polymer of 1,000,000 g / mol or more together, not only the adhesion to the electrode before charge and discharge, but also the adhesion to the electrode after charge and discharge, which is the environment in which the separator is actually used, can also be improved. After that, the shape stability of the battery can be improved.
  • the acrylic copolymer may further include an acetate group-containing monomer-derived repeating unit in addition to the (meth) acrylate-based monomer-derived repeating unit.
  • the weight ratio of the acrylic copolymer and the polyvinylidene fluoride polymer may be 5: 5 to 8: 2, specifically 6: 4 to 8: 2, and more specifically 7: 3 to 8: 2. Within the weight ratio range, it may be advantageous in view of good adhesion and electrolyte impregnation with the positive electrode or the negative electrode even after charging and discharging.
  • polyvinylidene fluoride polymer for example, polyvinylidene fluoride (PVdF) homopolymer, polyvinylidene fluoride-hexaxapropoxy (PVDF-HFP) copolymer, Or modified polymers thereof, and specifically, polyvinylidene fluoride-hexafluoropropylene copolymer or polyvinylidene fluoride homopolymer may be used.
  • the weight average molecular weight (Mw) of the polyvinylidene fluoride polymer may be in the range of 1,000,000 g / mol to 1,700,000 g / mol.
  • the weight average molecular weight (Mw) may range from 1,000,000 g / mol to 1,500,000 g / mol.
  • the use of the PVdF-based binder in the above molecular weight range has an advantage in that the adhesive force is enhanced after charge and discharge between the separator and the porous substrate, thereby producing a battery in which electrical output is efficiently generated.
  • the glass transition temperature (Tg) of the acrylic copolymer may be 100 ° C. or less, for example, 20 ° C. to 60 ° C. Within this range, the separator may be positioned between the electrodes and formed to have good adhesion at a temperature at which the separator is pressed, thereby improving the shrinkage rate and improving heat resistance.
  • the weight average molecular weight of the acrylic copolymer may be in the range of 100,000 g / mol to 1,000,000 g / mol, specifically 300,000 to 800,000 g / mol, or 400,000 to 700,000 g / mol.
  • the acrylic copolymer including a (meth) acrylate-based monomer-derived repeat unit that can be used herein is not particularly limited as long as it can form a good adhesion between the positive electrode and the negative electrode as described above, for example, butyl (meth It may be a copolymer produced by polymerizing one or more (meth) acrylate monomers selected from the group consisting of) acrylate, propyl (meth) acrylate, ethyl (meth) acrylate and methyl (meth) acrylate.
  • the acrylic copolymer is a (meth) acrylate monomer such as butyl (meth) acrylate, propyl (meth) acrylate, ethyl (meth) acrylate or methyl (meth) acrylate, and other monomers, for example, It may be a copolymer produced by polymerizing an acetate group-containing monomer such as vinyl acetate or allyl acetate.
  • the acetate group-containing monomer-derived repeating unit may be a repeating unit of Formula 1:
  • R 1 is a single bond, linear or branched alkyl having 1 to 6 carbon atoms
  • R 2 is hydrogen or methyl
  • l is an integer between 1 and 100, respectively.
  • the acetate group-containing monomer-derived repeating unit may be a repeating unit derived from an acetate group-containing monomer selected from at least one selected from the group consisting of vinyl acetate and allyl acetate.
  • the acryl-based copolymer is prepared by polymerizing a monomer other than the (meth) acrylate-based monomer and the (meth) acrylate-based monomer, for example, an acetate group-containing monomer, the (meth) acrylate-based monomer and the other monomer, specifically As such, the acetate group-containing monomer may be prepared by polymerization in a molar ratio of 3: 7 to 7: 3, specifically 4: 6 to 6: 4, and more specifically about 5: 5.
  • the acrylic copolymer may be a butyl (meth) acrylate monomer, a methyl (meth) acrylate monomer, and a vinyl acetate and / or allyl acetate monomer, in a weight ratio of 3 to 5: 0.5 to 1.5: 3 to 7, specifically, It may be prepared by a polymerization reaction of 4: 1: 5.
  • the inorganic particles used in the present invention are not particularly limited and may be inorganic particles commonly used in the art.
  • Non-limiting examples of the inorganic particles usable in the present invention include Al 2 O 3 , SiO 2 , B 2 O 3 , Ga 2 O 3 , TiO 2 , SnO 2 , and the like. These can be used individually or in mixture of 2 or more types.
  • As the inorganic particles used in the present invention for example, Al 2 O 3 (alumina) can be used.
  • the size of the inorganic particles used in the present invention is not particularly limited, but the average particle diameter may be 1 nm to 2,000 nm, for example, 100 nm to 1,000 nm, or 400 nm to 600 nm.
  • the inorganic particles When using the inorganic particles in the size range, it is possible to prevent the dispersibility of the inorganic particles in the adhesive layer composition and the fairness of the formation of the adhesive layer can be prevented from being lowered, and the thickness of the adhesive layer is appropriately adjusted to decrease the mechanical properties and increase the electrical resistance. Can be prevented. In addition, the size of the pores generated in the separator is appropriately adjusted, there is an advantage that can lower the probability of the internal short circuit occurs during the charge and discharge of the battery.
  • the inorganic particles may be used in the form of an inorganic dispersion in which it is dispersed in a suitable solvent.
  • the appropriate solvent is not particularly limited and may be a solvent commonly used in the art.
  • Acetone can be used as a suitable solvent for dispersing the inorganic particles, for example.
  • the inorganic dispersion may be prepared by a conventional method without any particular limitation. For example, Al 2 O 3 may be added to acetone in an appropriate amount, and the inorganic dispersion may be milled and dispersed using a bead mill. Dispersions can be prepared.
  • the inorganic particles in the adhesive layer may be included in 50 to 99% by weight, specifically 75 to 95% by weight, more specifically 80 to 95% by weight based on the total weight of the adhesive layer.
  • the heat dissipation characteristics of the inorganic particles may be sufficiently exhibited, and when the adhesive layer is formed on the porous substrate using the inorganic particles, thermal contraction of the separator may be effectively suppressed.
  • Non-limiting examples of the solvent usable in the present invention include acetone, dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), dimethylacetamide (dimethyl acetamide, DMAc), dimethyl carbonate , DMC) or N-methylpyrrolidone (N-methylpyrrolydone, NMP) and the like.
  • the content of the solvent may be 20 to 99% by weight, specifically 50 to 95% by weight, and more specifically 70 to 95% by weight based on the weight of the adhesive layer composition. When the solvent is contained in the above range, the preparation of the adhesive layer composition may be facilitated, and the drying process of the adhesive layer may be performed smoothly.
  • the adhesive layer or the adhesive layer composition according to another embodiment of the present invention may further include another binder in addition to the acrylic copolymer or the polyvinylidene fluoride polymer.
  • binders that may be added include polymethylmethacrylate (PMMA), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyvinylacetate (PVAc), polyethylene Oxides (PEO), cellulose acetate (CA), cellulose acetate butyrate (CAB), cellulose acetate propionate (CAP), cyanoethylpullulan (CANO) CYEPL), cyanoethylpolyvinylalcohol (CR-V), cyanoethylcellulose (CEC), cyanoethylsucrose, pullulan, carboxyl methyl cellulose CMC), and the group consisting of acrylonitrilestyrene-butadiene copolymer Or a mixture thereof.
  • PMMA polymethylmethacryl
  • the separator according to another embodiment of the present invention is a separator including a porous substrate and a binder-containing adhesive layer formed on one or both surfaces of the porous substrate, and after the charge and discharge of Equation 1 of the separator to the separator of the positive electrode or negative electrode active material
  • the transcription rates may each be at least 50%.
  • a 0 is the total area of the cathode or anode
  • a 1 forms an electrode assembly in which the anode, separator and cathode are sequentially stacked, and at a temperature of 20 ° C. to 110 ° C., 1 kgf / cm 2 , for 1 second to 5 seconds. 1 to 30 kgf / cm 2 , the first crimp, the electrolyte is injected into the compressed electrode assembly and 60 °C to 110 °C, 30 seconds to 180 seconds, with a force of 1 kgf / cm 2 to 30 kgf / cm 2 It is the area of the positive electrode or negative electrode active material transferred to the separator when the secondary pressing is carried out, and when charging, discharging, and charging are sequentially performed.
  • the method of measuring the area of the positive electrode or the negative electrode active material is not limited as long as the area of the active material can be measured.
  • a known image analyzer eg, a lumenera high resolution camera
  • a known image analyzer Example: Easy Measure converter 1.0.0.4
  • Easy Measure converter 1.0.0.4 can be used to measure the transferred area of the positive or negative electrode active material.
  • the transfer rate of the positive electrode or the negative electrode active material to the separator of 50% or more is related to the shape stability and adhesion of the battery after charge and discharge.
  • the transcription rate may be specifically 55% or more, more specifically 60% or more, even more specifically 70% or more.
  • an acrylic copolymer as described above and a polyvinylidene fluoride polymer having a weight average molecular weight of 1,000,000 g / mol or more may be used, and other inorganic particles, solvents, etc. may be used as described above. And in content.
  • the thickness change rate of Equation 2 may be 7% or less. Specifically, the thickness change rate may be 5% or less, and more specifically 3% or less.
  • Thickness Change (%) [(T 1 -T 2 ) / T 1 ] ⁇ 100 ⁇ 100
  • T 1 is a separator between the positive electrode and the negative electrode, and the positive electrode, the separator and the negative electrode is laminated in sequence of 7 cm (length direction) ⁇ 6.5 cm (width direction)
  • the thickness is measured by forming an electrode assembly
  • T 2 is the thickness measured after pressing the formed electrode assembly at a pressure of 1 kgf / cm 2 to 30 kgf / cm 2 at 20 ° C. to 110 ° C. for 1 to 5 seconds.
  • the shape stability of a battery is excellent in the said thickness change rate being the said range.
  • Separation membrane according to embodiments of the present invention may be less than 500 sec / 100cc, specifically 50 to 400 sec / 100cc, more specifically 50 to 300 sec / 100cc.
  • Tensile strength in the MD direction of the separator according to embodiments of the present invention may be 1750 kg / cm 2 or more, the tensile strength in the TD direction may be 1650 kg / cm 2 or more.
  • the tensile strength in the MD direction of the separator may be 1750 kg / cm 2 to 2550 kg / cm 2
  • the tensile strength in the TD direction may be 1700 kg / cm 2 to 2500 kg / cm 2 .
  • the separator according to the examples of the present invention may not only have excellent shape stability and adhesion after charge and discharge, but also satisfy basic physical properties such as air permeability and mechanical strength required as the separator.
  • Method for producing a separator according to an embodiment of the present invention comprises an acrylic copolymer containing a (meth) acrylate monomer-derived repeating unit, and a polyvinylidene fluoride polymer having a weight average molecular weight of 1,000,000 g / mol or more bookbinder; And forming an adhesive layer composition comprising a solvent, and forming the adhesive layer with the adhesive layer composition on one or both surfaces of the porous substrate.
  • the acrylic copolymer may further include a repeating unit derived from an acetate group-containing monomer such as vinyl acetate or allyl acetate monomer.
  • the adhesive layer composition is a binder comprising an acrylic copolymer and a polyvinylidene fluoride polymer having a weight average molecular weight of 1,000,000 g / mol or more, and a solvent and mixed at 10 to 40 °C for 30 minutes to 5 hours It may include stirring.
  • the stirred solution may include inorganic particles.
  • the content of the solid content may be 10 to 20 parts by weight based on the adhesive layer composition, the weight ratio of the binder and the inorganic particles in the solid content may be 5: 5 to 0.1: 9.9.
  • the adhesive layer composition may be prepared by preparing an inorganic dispersion in which the inorganic particles are dispersed in a dispersion medium and mixing the mixture with a polymer solution containing a solvent and a binder including an acrylic copolymer and a polyvinylidene fluoride polymer.
  • the inorganic dispersion is prepared separately as described above, the dispersibility and crude liquid stability of the inorganic particles and the binder may be improved. Therefore, in another embodiment, in preparing the adhesive layer composition of the present invention, the binder component and the inorganic particles may be prepared and mixed in a dissolved or dispersed state in a suitable solvent, respectively.
  • an adhesive layer composition may be prepared by preparing a solution in which each of an acrylic copolymer and a polyvinylidene fluoride binder are dissolved in a suitable solvent, and an inorganic dispersion in which inorganic particles are dispersed, and then mixing them with an appropriate solvent. It can manufacture.
  • a ball mill, a beads mill, a screw mixer, or the like may be used for the mixing.
  • an adhesive layer is formed of the adhesive layer composition on one or both surfaces of the porous substrate.
  • the method for forming the adhesive layer on the porous substrate is not particularly limited, and methods commonly used in the art, for example, a coating method, lamination, coextrusion, and the like may be used.
  • Non-limiting examples of the coating method may include a dip coating method, a die coating method, a roll coating method, or a comma coating method. These may be applied alone or in combination of two or more methods.
  • the adhesive layer of the separator of the present invention may be formed by, for example, a dip coating method.
  • the adhesive layer of the present invention may have a thickness of 0.01 to 20 ⁇ m, specifically 1 to 10 ⁇ m, and more specifically 1 to 5 ⁇ m. Within the thickness range, it is possible to form an adhesive layer having an appropriate thickness to obtain excellent thermal stability and adhesion, and to prevent the thickness of the entire separator from becoming too thick, thereby suppressing an increase in the internal resistance of the battery.
  • the adhesive layer may be dried by hot air, hot air, low humidity, vacuum drying or far infrared rays or electron beams.
  • the drying temperature is different depending on the type of the solvent, it can be dried at a temperature of approximately 60 to 120 °C.
  • the drying time also varies depending on the type of solvent, but may generally be dried for 1 minute to 1 hour. In embodiments, it may be dried for 1 minute to 30 minutes, or 1 minute to 10 minutes at a temperature of 70 to 120 °C.
  • an anode positioned between the anode and the cathode; And it provides a secondary battery comprising an electrolyte.
  • the type of the secondary battery is not particularly limited and may be a battery of a kind known in the art.
  • the secondary battery of the present invention may be a lithium secondary battery such as a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery.
  • the method of manufacturing the secondary battery of the present invention is not particularly limited, and a method commonly used in the technical field of the present invention may be used.
  • a non-limiting example of a method of manufacturing the secondary battery is as follows: A porous separator comprising the adhesive layer of the present invention is placed between the positive electrode and the negative electrode of the battery, and then the battery is prepared by filling an electrolyte therein. Can be.
  • FIG. 1 and 2 are exploded perspective views of a secondary battery according to one or another embodiment.
  • the secondary battery according to the embodiment is described as an example of a rectangular or cylindrical battery, the present invention is not limited thereto, and may be applied to various types of batteries such as pouch-type batteries and lithium polymer batteries.
  • the secondary batteries 100 and 200 may have a odor through the separators 30 and 30 'between the cathodes 10 and 10' and the anodes 20 and 20 '.
  • the positive electrode 10, 10 ′, the negative electrode 20, 20 ′ and the separator 30, 30 ′ are impregnated with an electrolyte (not shown).
  • the positive electrodes 10 and 10 ′ may include a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector.
  • the positive electrode active material layer may include a positive electrode active material, a binder, and optionally a conductive material.
  • aluminum (Al), nickel (Ni), or the like may be used, but is not limited thereto.
  • a compound capable of reversible intercalation and deintercalation of lithium may be used. Specifically, at least one of cobalt, manganese, nickel, aluminum, iron, or a combination of metal and lithium composite oxide or phosphoric acid may be used. More specifically, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate or a combination thereof may be used.
  • the binder not only adheres the positive electrode active material particles well to each other, but also serves to adhere the positive electrode active material to the positive electrode current collector, and specific examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, and polyvinyl chloride.
  • Carboxylated polyvinylchloride polyvinylfluoride, ethylene oxide containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, Acrylated styrene-butadiene rubber, epoxy resin, nylon and the like, but is not limited thereto. These can be used individually or in mixture of 2 or more types.
  • the conductive material provides conductivity to the electrode, and examples thereof include natural graphite, artificial graphite, carbon black, carbon fiber, metal powder, and metal fiber, but are not limited thereto. These can be used individually or in mixture of 2 or more types.
  • metal powder and the metal fiber metals such as copper, nickel, aluminum, and silver may be used.
  • the negative electrodes 20 and 20 ′ may include a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector.
  • the negative electrode current collector may include copper (Cu), gold (Au), nickel (Ni), a copper alloy, or the like, but is not limited thereto.
  • the negative electrode active material layer may include a negative electrode active material, a binder, and optionally a conductive material.
  • the negative electrode active material may be a material capable of reversibly intercalating and deintercalating lithium ions, a lithium metal, an alloy of lithium metal, a material capable of doping and undoping lithium, a transition metal oxide, or a combination thereof. Can be used.
  • Examples of a material capable of reversibly intercalating and deintercalating the lithium ions include carbon-based materials, and examples thereof include crystalline carbon, amorphous carbon, or a combination thereof.
  • Examples of the crystalline carbon may be amorphous, plate, flake, spherical or fibrous natural graphite or artificial graphite.
  • Examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.
  • Examples of the alloy of the lithium metal include lithium and Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn. Alloys of the metals selected may be used.
  • Examples of materials capable of doping and undoping lithium include Si, SiO x (0 ⁇ x ⁇ 2), Si-C composites, Si-Y alloys, Sn, SnO 2 , Sn-C composites, Sn-Y, and the like. And at least one of these and SiO 2 may be mixed and used.
  • transition metal oxide examples include vanadium oxide and lithium vanadium oxide.
  • Kinds of the binder and the conductive material used in the negative electrode are the same as the binder and the conductive material used in the above-described positive electrode.
  • the positive electrode and the negative electrode may be prepared by mixing each active material, a binder, and optionally a conductive material in a solvent to prepare each active material composition, and applying the active material composition to each current collector.
  • N-methylpyrrolidone may be used as the solvent, but is not limited thereto. Since such an electrode manufacturing method is well known in the art, detailed description thereof will be omitted.
  • the electrolyte solution contains an organic solvent and a lithium salt.
  • the organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.
  • Specific examples thereof may be selected from carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents and aprotic solvents.
  • the carbonate solvent examples include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene Carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and the like.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • MPC methylpropyl carbonate
  • EPC ethylpropyl carbonate
  • EMC ethylmethyl carbonate
  • EMC ethylmethyl carbonate
  • EC ethylene Carbonate
  • PC propylene carbonate
  • BC butylene carbonate
  • ester solvents examples include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, ⁇ -butyrolactone, decanolide, valerolactone, and meronate. Melononolactone, caprolactone, and the like.
  • ether solvent examples include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, tetrahydrofuran and the like. Cyclohexanone etc. are mentioned as said ketone solvent, Ethyl alcohol, isopropyl alcohol, etc. are mentioned as said alcohol solvent.
  • the organic solvents may be used alone or in combination of two or more thereof, and the mixing ratio in the case of mixing two or more kinds may be appropriately adjusted according to the desired battery performance.
  • the lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions in the battery to enable operation of a basic secondary battery and to promote the movement of lithium ions between the positive electrode and the negative electrode.
  • lithium salt examples include LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN (SO 3 C 2 F 5 ) 2 , LiN (CF 3 SO 2 ) 2 , LiC 4 F 9 SO 3 , LiClO 4 , LiAlO 2 , LiAlCl 4 , LiN (C x F 2x + 1 SO 2 ) (C y F 2y + 1 SO 2 ) (x and y are natural numbers), LiCl, LiI, LiB (C 2 O 4 ) 2 or a combination thereof Can be mentioned.
  • the concentration of the lithium salt can be used within the range of 0.1M to 2.0M.
  • concentration of the lithium salt is within the above range, since the electrolyte has an appropriate conductivity and viscosity, it can exhibit excellent electrolyte performance, and lithium ions can move effectively.
  • Acetone is an acrylic copolymer binder in which butyl methacrylate (BMA), methyl methacrylate (MMA), and vinyl acetate (Vinyl Acetate, VAc) are polymerized at a 4/1/5 molar ratio.
  • BMA butyl methacrylate
  • MMA methyl methacrylate
  • VAc vinyl acetate
  • Dissolved in the first binder solution having a solid content of 5% by weight and a PVdF-based polymer (Kurehasa KF9300, Mw: 1,200,000 g / mol) in acetone and DMAc mixed solvents to dissolve a second binder solution which is a 7% by weight solid solution.
  • Alumina dispersion was prepared by adding alumina (LS235, Nippon Light Metal) to acetone at 25% by weight and dispersing the beads for 3 hours.
  • the first and second binder solutions and the alumina dispersion were mixed so that the weight ratio of the above-mentioned acrylic binder and the PVdF-based binder was 6: 4, so that the weight ratio of the binder solid and the alumina solid was 1/6, and the total solid was 12 wt.
  • Acetone was added to make the coating solution.
  • 7 ⁇ m thick polyethylene fabric (SK, Inc.) was coated on both sides of the coating solution with a thickness of 2 ⁇ m, respectively, to prepare a separator having a total thickness of about 11 ⁇ m.
  • Example 2 The separation membrane of Example 2 was prepared in the same manner as in Example 1, except that the weight ratio of the acrylic binder and the PVdF binder was 7: 3 in Example 1.
  • Example 3 The separator of Example 3 was prepared in the same manner as in Example 1, except that the weight ratio of the acrylic binder and the PVdF binder was 8: 2 in Example 1.
  • a separator of Example 4 was prepared in the same manner as in Example 1, except that 5130 (Solva, Inc., weight average molecular weight: 1,000,000 to 1,200,000 g / mol) was used as the second binder in Example 1. .
  • the separation membrane of Example 5 was prepared in the same manner as in Example 4, except that the weight ratio of the acrylic binder and the 5130 binder was 7: 3 in Example 4.
  • the separator of Example 6 was prepared in the same manner as in Example 4, except that the weight ratio of the acrylic binder and the 5130 binder was 8: 2.
  • Comparative Example 1 was carried out in the same manner as in Example 1 except that 21216 (Solva, Inc., weight average molecular weight: 570,000 to 700,000 g / mol, PVDF-HFP copolymer) was used instead of KF9300 in Example 1 A separator of 1 was prepared.
  • 21216 Solva, Inc., weight average molecular weight: 570,000 to 700,000 g / mol, PVDF-HFP copolymer
  • a separation membrane of Comparative Example 2 was prepared in the same manner as in Comparative Example 1 except that the weight ratio of the acrylic binder and the 21216 binder was 7: 3 in Comparative Example 1.
  • the separation membrane of Comparative Example 3 was prepared in the same manner as in Comparative Example 1, except that the weight ratio of the acrylic binder and the 21216 binder was 8: 2 in Comparative Example 1.
  • Example 1 except that 6020 (Solva, Inc., weight average molecular weight: 670,000 to 700,000 g / mol, PVDF homopolymer) was used as the second binder in a weight ratio of 7: 3 in the same manner as in Example 1, except that KF9300 was used.
  • the separation membrane of Comparative Example 4 was prepared.
  • Each of the separators prepared in the above Examples and Comparative Examples was prepared to cut 10 samples cut from 10 different points to a size of 1 inch (1 inch) in diameter, and then the air permeability measuring device (Asahi Seiko) G) was used to measure the time for passage of 100 cc of air in each sample. The time was measured five times each, and then the average value was calculated as air permeability.
  • Each of the separators prepared in Examples and Comparative Examples was cut into five pieces in a rectangular shape of 50 mm long by 150 mm long by 150 mm long by MD, and by 150 mm long by 50 mm wide by 50 mm long.
  • Ten samples were prepared, and each sample was mounted on a UTM (tension tester) to be bitten to a measurement length of 20 mm, and then the sample was pulled to measure average tensile strength in the MD and TD directions.
  • the following method was performed to measure the thickness and rate of change of the electrode assembly having the separator prepared in Examples and Comparative Examples interposed between the positive electrode and the negative electrode.
  • LCO LiCoO 2
  • anode active material was coated on both sides of an aluminum foil having a thickness of 14 ⁇ m with a thickness of 94 ⁇ m, dried, and rolled to produce a cathode having a total thickness of 108 ⁇ m.
  • Graphite 1: 1 was coated on both sides of copper foil having a thickness of 8 ⁇ m at 120 ⁇ m, dried, and rolled to prepare a negative electrode having a total thickness of 128 ⁇ m.
  • the anode and the cathode were cut in 100 cm (length direction) ⁇ 6.3 cm (width direction), respectively, and the separators prepared in Examples and Comparative Examples were cut in 100 cm (length direction) ⁇ 6.5 cm (width direction). Thereafter, the electrode assembly was wound up to 7 cm (length direction) x 6.5 cm (width direction) between the positive electrode and the negative electrode to form an electrode assembly, and the thickness of the electrode assembly was measured using a 30 cm steel ruler (T 1 ).
  • the electrode assembly was pressed at 100 ° C. at a pressure of 5 kgf / cm 2 for 3 seconds, and the thickness of the electrode assembly was measured using a 30 cm steel ruler (T 2 ), and the thickness change rate was calculated by the following Equation 2.
  • Thickness Change (%) [(T 1 -T 2 ) / T 1 ] ⁇ 100
  • LCO LiCoO 2
  • a positive electrode active material LCO (LiCoO 2) was coated on both sides of an aluminum foil having a thickness of 14 ⁇ m with a thickness of 94 ⁇ m, dried, and rolled to prepare a positive electrode having a total thickness of 108 ⁇ m.
  • a negative electrode active material natural graphite and artificial graphite (1: 1) were coated on both sides of a copper foil having a thickness of 8 ⁇ m at 120 ⁇ m, dried, and rolled to prepare a negative electrode having a total thickness of 128 ⁇ m.
  • the separators prepared in Examples and Comparative Examples were wound between the anode and the cathode with an electrode assembly of 7 cm ⁇ 6.5 cm.
  • the electrode assembly was first pressed at 100 ° C. for 3 seconds under a pressure of 5 kgf / cm 2 , placed in an aluminum coated pouch (8 cm ⁇ 12 cm), and the two adjacent corners were sealed at a temperature of 143 ° C., followed by 6.5 g of the electrolyte solution. Was added and sealed so that no air remained in the battery using a degassing machine for at least 3 minutes.
  • the prepared battery was aged at 25 ° C. for 12 hours, and then pressed at 110 ° C. for 120 seconds under a pressure of 20 kgf / cm 2 .
  • the cell was dismantled to photograph an area where an active material of a negative electrode or a positive electrode was transferred to a separator (lumenera high resolution camera), and the image was transferred using an image analyzer (Easy Measure converter 1.0.0.4) to calculate the transferred area. It was set as the transcription rate.
  • the electrode assembly was continuously aged at 25 ° C.
  • the battery was dismantled, and the area transferred from the active material of the negative electrode or the positive electrode to the separator was measured by the same method as the transfer rate before charge and discharge, and the transfer rate after charge and discharge was determined.
  • the thickness change rate was greater than 7%, and the separator was formed before and after charge and discharge. The transfer rate could not be measured because it was separated from the negative electrode or the positive electrode.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Cell Separators (AREA)

Abstract

La présente invention concerne un séparateur et une batterie rechargeable dotée du séparateur, le séparateur comprenant : un substrat poreux ; et une couche adhésive formée sur un côté ou sur les deux côtés du substrat poreux, la couche adhésive contenant un copolymère acrylique comprenant une unité répétitive dérivée de monomères à base (méth)acrylate, et un polymère à base de fluorure de polyvinylidène ayant un poids moléculaire moyen en poids d'au moins 1 000 000 g/mol.
PCT/KR2014/011179 2013-11-21 2014-11-20 Séparateur et batterie rechargeable l'utilisant WO2015076574A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
KR10-2013-0142324 2013-11-21
KR20130142324 2013-11-21
KR20140041124 2014-04-07
KR10-2014-0041124 2014-04-07
KR10-2014-0133340 2014-10-02
KR1020140133340A KR20150106810A (ko) 2013-11-21 2014-10-02 분리막 및 이를 이용한 이차 전지

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Cited By (4)

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CN108448032A (zh) * 2017-02-16 2018-08-24 帝人株式会社 非水系二次电池用隔膜及非水系二次电池
CN109565021A (zh) * 2016-09-21 2019-04-02 帝人株式会社 非水系二次电池用隔膜及非水系二次电池
CN111312971A (zh) * 2020-03-02 2020-06-19 荣盛盟固利新能源科技有限公司 一种隔膜、二次电池及其制备方法
EP3734701A4 (fr) * 2018-09-21 2021-04-21 Lg Chem, Ltd. Séparateur et dispositif électrochimique le comprenant

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KR20110057079A (ko) * 2009-11-23 2011-05-31 주식회사 엘지화학 다공성 코팅층을 구비한 분리막의 제조방법, 이로부터 형성된 분리막 및 이를 구비한 전기화학소자
KR20130123568A (ko) * 2012-05-03 2013-11-13 주식회사 엘지화학 전기화학소자용 분리막, 이의 제조방법 및 이를 포함하는 전기화학소자

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JP2004063343A (ja) * 2002-07-30 2004-02-26 Toshiba Corp リチウムイオン二次電池
KR100727248B1 (ko) * 2007-02-05 2007-06-11 주식회사 엘지화학 다공성 활성층이 코팅된 유기/무기 복합 분리막 및 이를구비한 전기화학소자
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CN109565021A (zh) * 2016-09-21 2019-04-02 帝人株式会社 非水系二次电池用隔膜及非水系二次电池
CN108448032A (zh) * 2017-02-16 2018-08-24 帝人株式会社 非水系二次电池用隔膜及非水系二次电池
EP3734701A4 (fr) * 2018-09-21 2021-04-21 Lg Chem, Ltd. Séparateur et dispositif électrochimique le comprenant
US11784377B2 (en) 2018-09-21 2023-10-10 Lg Energy Solution, Ltd. Separator including porous coating layer with amorphous adhesive binder polymer and fluorinated binder polymer and electrochemical device including the same
CN111312971A (zh) * 2020-03-02 2020-06-19 荣盛盟固利新能源科技有限公司 一种隔膜、二次电池及其制备方法

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