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WO2018147714A1 - Film de séparation pour batterie secondaire au lithium à couche adhésive - Google Patents

Film de séparation pour batterie secondaire au lithium à couche adhésive Download PDF

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Publication number
WO2018147714A1
WO2018147714A1 PCT/KR2018/001907 KR2018001907W WO2018147714A1 WO 2018147714 A1 WO2018147714 A1 WO 2018147714A1 KR 2018001907 W KR2018001907 W KR 2018001907W WO 2018147714 A1 WO2018147714 A1 WO 2018147714A1
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WO
WIPO (PCT)
Prior art keywords
binder
coating composition
weight
inorganic particles
hfp
Prior art date
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PCT/KR2018/001907
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English (en)
Korean (ko)
Inventor
정소미
성동욱
장대성
Original Assignee
주식회사 엘지화학
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 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to EP18751649.7A priority Critical patent/EP3518318B1/fr
Priority to JP2019528486A priority patent/JP6824559B2/ja
Priority to CN201880004178.XA priority patent/CN110249447B/zh
Priority to PL18751649.7T priority patent/PL3518318T3/pl
Priority to US16/341,805 priority patent/US11721873B2/en
Priority to ES18751649T priority patent/ES2969212T3/es
Priority claimed from KR1020180018027A external-priority patent/KR102311624B1/ko
Publication of WO2018147714A1 publication Critical patent/WO2018147714A1/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
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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 coating composition for a lithium secondary battery separator having an adhesive layer, and more particularly, to a coating composition for a lithium secondary battery separator having an adhesive layer for coating at least one surface of a porous substrate separator having a plurality of pores.
  • the lithium secondary battery may cause an explosion due to heat generation depending on the usage environment.
  • a separator particularly a technology for increasing the bonding force between the porous coating layer and the electrode of the separator. Strong bonding of the separator and the electrode can increase the safety of the battery.
  • a binder that suppresses an increase in the interfacial resistance between the separator and the electrode due to an electrode side reaction generated during a cycle and improves air permeability, and a separator using the same.
  • Patent Literature 1 includes a separator including an adhesive layer and a separator applicable to a secondary battery as a secondary battery using the same, and a secondary battery capable of maintaining the shape stability and adhesion of the battery even after charging and discharging, which is an environment in which an actual battery is used. to provide.
  • Patent document 1 is a porous base material; And an adhesive layer formed on one or both sides of the substrate, wherein the adhesive layer includes a vinylidene fluoride-derived unit and a polyvinylidene fluoride (PVDF) system having a hexafluoropropylene (HFP) -derived unit content of 5% by weight or less.
  • PVDF polyvinylidene fluoride
  • a polyvinylidene fluoride (PVDF) comprising a first binder, a vinylidene fluoride derived unit and a hexafluoropropylene (HFP) derived unit, wherein the hexafluoropropylene (HFP) derived unit content is 10 to 30% by weight;
  • a second binder wherein the weight ratio of the polyvinylidene fluoride (PVDF) -based first binder and the polyvinylidene fluoride (PVDF) -based second binder is 0.5: 9.5 to 2: 8, and includes the separator. It relates to a secondary battery.
  • Patent document 2 relates to a separator having a binder layer, an electrochemical device including the separator, and a manufacturing method of the separator, in order to solve the safety problem of the secondary battery, the bonding strength of the separator, in particular, the porous coating layer of the separator and the electrode. It was raised.
  • the strong bonding of the separator and the electrode enhances the safety of the battery, and provides a binder that suppresses an increase in the interfacial resistance between the separator and the electrode due to an electrode side reaction generated during the cycle and improves air permeability.
  • Patent Literature 2 includes a porous substrate, a porous coating layer and a binder layer, wherein the binder present in the porous coating layer and the binder layer includes two or more polyvinylidene flues having a hexafluoropropylene (HFP) content difference of 3% by weight or more.
  • Separation membranes are provided that include a vinylidene (PVDF) homopolymer or a polyvinylidene fluoride-co-hexafluoropropylene (P (VDF-HFP)) based copolymer.
  • PVDF vinylidene
  • PVDF-HFP polyvinylidene fluoride-co-hexafluoropropylene
  • binder solution Forming a binder solution, forming a slurry, and forming a porous coating layer, wherein the binder in the binder solution comprises at least two PVDF homopolymers or P (VDF-HFP) -based air having a HFP content difference of at least 3% by weight; Also provided is a method of preparing a separator comprising coalescing.
  • Patent document 3 relates to a battery cell including a separator with enhanced adhesion, even if the organic-inorganic porous coating layer is coated on a porous polymer substrate with a thin thickness to exhibit excellent adhesion to the electrode, it is possible to improve the thermal shrinkage of the separator Provide a separator.
  • Patent document 3 is a battery cell in which an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode is built in a battery case, wherein the separator is on at least one surface of the porous polymer substrate and the porous polymer substrate Including an organic-inorganic porous coating layer formed, the organic-inorganic porous coating layer, inorganic particles including a mixture of metal oxide and metal hydroxide, PVDF-HFP polymer binder having a high hexafluoropropylene (HFP) content (' PHFP high ') and a mixture of PVDF-HFP polymer binder (' PHFP low ') having a low HFP content, the separator, and the adhesion between the positive electrode or the negative electrode relates to a battery cell characterized in that more than 15gf / 25mm .
  • HFP hexafluoropropylene
  • Patent document 4 relates to an electrode having an improved adhesive force and a lithium secondary battery including the same, and provides a method capable of increasing the binding force between the electrode current collector and the electrode mixture layer and reducing the binder content contained in the electrode mixture layer.
  • Patent document 4 is an electrode in which an electrode mixture containing an electrode active material is coated on an electrode current collector, wherein the electrode mixture includes a mixture of two or more binders having different specific gravity.
  • the binder layer of the separator of a lithium secondary battery uses a method of inducing phase separation so that a binder is widely distributed on the surface by coating a slurry including a solvent, a binder, a dispersant, and inorganic particles under humidification.
  • a method of inducing phase separation so that a binder is widely distributed on the surface by coating a slurry including a solvent, a binder, a dispersant, and inorganic particles under humidification.
  • Such a method is very sensitive to humidification conditions, and various changes in phase separation form may occur depending on humidity conditions, and in some cases, an adhesive layer may not sufficiently apply a surface.
  • phase separation when the phase is sufficiently dried before the adhesive layer is not formed on the surface does not implement sufficient adhesive strength.
  • the adhesion between the porous substrate and the coating layer and the binding force between the inorganic particles may be lowered.
  • the thickness of the coating layer is thinned from 4 ⁇ m or more to 3 ⁇ m, a problem arises in that the binder is dried before sufficient phase separation to obtain sufficient electrode adhesion.
  • the adhesive layer is separated and positioned on the surface side, but when the thin film is coated on the thickness of 3 ⁇ m or less (Fig. 1 (b)), the adhesive layer is not separated and sufficient adhesive strength with the electrode Is not implemented (see FIG. 1).
  • two or more binders having different composition ratios of PVDF and HPF were used similarly to the present invention, but both could not provide the desired electrode adhesion through sufficient phase separation for the thin film coating at both humidification conditions and 3 ⁇ m.
  • Patent Document 0001 Republic of Korea Patent Publication No. 10-2016-0117962
  • Patent Document 0002 Republic of Korea Patent Publication No. 10-2014-0050877
  • Patent Document 0003 Republic of Korea Patent Publication No. 10-2016-0108116
  • Patent Document 0004 Republic of Korea Patent Publication No. 10-2013-0117350
  • an object of the present invention is to provide a coating composition for a separator in which the bonding force between the porous coating layer and the electrode of the separator is increased.
  • the present invention increases the safety of the battery through strong bonding of the separator and the electrode, suppresses the increase in the interfacial resistance of the separator and the electrode by the electrode side reaction generated during the cycle, the coating composition for a separator comprising a binder to improve the air permeability
  • the coating layer (cross section basis) of the separator was thinned from 4 ⁇ m to 3 ⁇ m, the binder was dried before sufficient phase separation, and sufficient electrode adhesion was not obtained. Also, in the manufacturing method, sufficient phase separation was achieved even under low humidity conditions. It is intended to provide a coating composition that can occur.
  • the present invention for solving the above problems is a coating composition
  • a coating composition comprising a solvent, an inorganic particle, a dispersant, a binder for coating at least one surface of a porous substrate having a plurality of pores, the binder is binder B and binder A
  • both the binder B and the binder A include a vinylidene fluoride (VDF) derived unit and a hexafluoropropylene (HFP) derived unit, wherein the HFP derived unit accounts for 8 to 50% by weight of the binder B, and the binder In A, it is 80% or less of the ratio of binder B and 5% by weight or more of binder A, the total number average molecular weight of binder B is 200,000 to 2 million, and the total number average molecular weight of binder A is 70% or less of binder B.
  • VDF vinylidene fluoride
  • HFP hexafluoropropylene
  • the binder B and the binder A may be composed of vinylidene fluoride (VDF) and hexafluoropropylene (HFP).
  • Vinylidene fluoride-derived copolymers including poly (vinylidene fluoride-co-chlorotrifluoroethylene, poly (vinylidene fluoride-co-trifluoroethylene), etc., in addition to binder B and binder A, polymethylmetha Polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylene-co-vinyl acetate, polyethylene oxide Cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyano Cyanoethylcellulose, cyanoethylsucrose, Pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer, or polyimide, alone or in combination of two or more thereof May be included as an additional binder.
  • the porous substrate is polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polyamide, poly Carbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polybenzimidazole, polybenzimidazole, polybenzimidazole Any one polymer selected from the group consisting of polyethersulfone, polyphenyleneoxide, cyclic olefin high polymer, cyclicolefin copolymer, polyphenylenesulfide and polyethylenenaphthalene Tombs formed from mixtures of more than one species A film or a multi-film, a woven fabric or nonwoven fabric.
  • the dispersant is one or a mixture of two or more selected from the group consisting of acrylic copolymers, and the inorganic particles are selected from the group consisting of inorganic particles having a dielectric constant of 5 or more, inorganic particles having lithium ion transfer ability, and mixtures thereof. .
  • the inorganic particles may be formed of two or more kinds of different sizes.
  • the inorganic particles A having a D50 of 200 nm to 1 ⁇ m and the D50 may be composed of an inorganic B having 70% or less of the inorganic particles A.
  • the content of the binder is 3 to 50 parts by weight based on 100 parts by weight of the inorganic particles, and the content of the dispersant is 0.5 to 5 parts by weight based on 100 parts by weight of the inorganic particles.
  • the present invention provides a separator coated by the coating composition. At this time, the thickness of the coating is 3 ⁇ m or less based on the cross section.
  • the present invention provides an electrochemical device, preferably a lithium secondary battery comprising a positive electrode, a negative electrode, and the separator interposed between the positive electrode and the negative electrode.
  • the humidification conditions are provided in 35 to 45% coating thickness of 3 ⁇ m or less do.
  • 1 is a photograph observing the phenomenon occurring during the coating 4a or more coating (a) and 3 ⁇ m or less thin film coating (b) using a conventional technique with an electron microscope.
  • FIG. 2 is a photograph of an embodiment according to the present invention observed with an electron microscope.
  • Figure 3 is a photograph of the Comparative Example 1 according to the present invention observed with an electron microscope.
  • Figure 4 is a photograph of the Comparative Example 2 according to the present invention observed with an electron microscope.
  • the present invention provides a coating composition comprising a solvent, inorganic particles, a dispersant, and a binder for coating at least one side of a porous substrate having a plurality of pores.
  • the porous substrate is polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate (polycarbonate), polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyether Any one polymer selected from the group consisting of sulfon (polyethersulfone), polyphenylene oxide, cyclic olefin high polymer (cyclic olefin copolymer), polyphenylene sulfide and polyethylene naphthalene (polyethylenenaphthalene) or two of them
  • Polymer membrane formed of the above mixture It may be those of a multi-film, a woven or non-woven fabric, but are not limited to.
  • the thickness of the porous substrate is not particularly limited, but may be about 5 to about 50 ⁇ m, and the pore size and pore present in the porous substrate are also not particularly limited, but about 0.01 to about 50 ⁇ m, and about 10 to about 95, respectively. May be%.
  • the solubility index is similar to the binder to be used, and the boiling point is preferably low. This is because mixing can be made uniform, and then the solvent can be easily removed.
  • the solvent is preferably a polar solvent having a boiling point of less than 100.
  • a nonpolar solvent it is not preferable because there exists a possibility of the fall of dispersion force.
  • Non-limiting examples of solvents include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (Nmethyl- 2-pyrrolidone, NMP), cyclohexane (cyclohexane), water, etc. may be one or a mixture of two or more selected from the group consisting of.
  • the solvent comprises about 50 parts by weight to about 90 parts by weight based on 100 parts by weight of the total amount of solids and the solvent, that is, 100 parts by weight of the total amount of the solid mixture of the inorganic material, the binder, and the dispersant and the solvent (eg, the polar solvent). If the solvent is less than 50 parts by weight based on 100 parts by weight of the total content of the solid and the solvent, the coating property is deteriorated due to the increase in viscosity, a great difficulty in forming the binder layer exists, and there is a difficulty in thinning the film. It can lead to a decrease and an increase in manufacturing cost.
  • the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as the oxidation and / or reduction reactions do not occur in the operating voltage range (for example, 0 to about 5 V on the basis of Li / Li +) of the electrochemical device to be applied. In particular, in the case of using the inorganic particles having the ion transport ability, it is possible to improve the performance by increasing the ion conductivity in the electrochemical device.
  • the ionic conductivity of the electrolyte may be improved by contributing to an increase in the dissociation degree of the electrolyte salt such as lithium salt in the liquid electrolyte.
  • the inorganic particles may include high dielectric constant inorganic particles having a dielectric constant of about 5 or more, such as about 10 or more, inorganic particles having a lithium ion transfer ability, or a mixture thereof.
  • inorganic particles having a dielectric constant of about 5 or more include BaTiO 3 , Pb (Zr, Ti) O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), PB (Mg 3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT), Hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC, Al (OH) 3, or mixtures thereof.
  • the inorganic particles having a lithium ion transfer capacity refers to inorganic particles containing lithium elements but having a function of transferring lithium ions without storing lithium, and the inorganic particles having lithium ion transfer ability are present in the particle structure. Since the lithium ions can be transferred and moved due to a kind of defect, the lithium ion conductivity in the battery is improved, thereby improving battery performance.
  • Non-limiting examples of the inorganic particles having a lithium ion transfer capacity include lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (LixTiy (PO 4 ) 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 3), lithium aluminum (LiAlTiP) such as LixAlyTiz (PO 4 ) 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 3), 14Li 2 O-9Al 2 O 3 -38TiO 2 -39P 2 O 5, etc.
  • lithium phosphate Li 3 PO 4
  • LiixTiy (PO 4 ) 3 lithium titanium phosphate
  • LiAlTiP lithium aluminum
  • LixAlyTiz (PO 4 ) 3 such as LixAlyTiz (PO 4 ) 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 3)
  • Li x O y series glass (0 ⁇ x ⁇ 4, 0 ⁇ y ⁇ 13), lithium lanthanum titanate (Li x La y TiO 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 3), Li 3.25 Ge 0.25 P 0.75 Lithium germanium thiophosphate such as S 4 (LixGeyPzSw, 0 ⁇ x ⁇ 4, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ w ⁇ 5), lithium nitride such as Li 3 N (LixNy, 0 SiS 2 series glass (Li x Si y S z , 0 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 2, 0) such as ⁇ x ⁇ 4, 0 ⁇ y ⁇ 2), Li 3 PO 4 -Li 2 S-SiS 2, etc.
  • P 2 S 5 series glass Li x P y S z , 0 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 3, 0 ⁇ z ⁇ 7, such as LiI-Li 2 SP 2 S 5 , or these And mixtures thereof.
  • the inorganic particle size is not limited, but may be about 0.01 to about 10 ⁇ m, or about 0.05 to about 1.0 ⁇ m, as much as possible for uniform coating thickness formation and proper porosity.
  • the size of the inorganic particles satisfies the above range, the dispersibility is improved to easily control the physical properties of the separator, the thickness of the porous coating layer is increased to decrease the mechanical properties or due to excessively large pore size during battery charging and discharging The problem of an internal short circuit can be prevented.
  • the inorganic particles may be composed of two or more kinds of different sizes.
  • the inorganic particles A having a D50 of 200 nm to 1 ⁇ m and the D50 may be composed of an inorganic B having 70% or less of the inorganic particles A.
  • the dispersant may be one or a mixture of two or more selected from the group consisting of acrylic copolymers. This dispersant functions as an excellent dispersant for improving the dispersibility of inorganic matter. In addition, the dispersant has an excellent function as the dispersant and a function as a binder having adhesion.
  • This dispersant comprises a polar group, by having such a polar group can interact with the surface of the inorganic material to increase the dispersibility of the inorganic material.
  • the dispersant is easy to control the physical properties of the dispersing and the adhesion can be improved in the balance it can contribute to the stability of the separator and the electrochemical device using the separator.
  • the acrylic copolymer may be a copolymer including one or two or more functional groups selected from the group consisting of OH, COOH, CN, amine and amide groups.
  • This acrylic copolymer may be a copolymer comprising at least one first functional group and at least one second functional group.
  • the first functional group may be selected from the group consisting of OH groups and COOH groups
  • the second functional group may be selected from the group consisting of amine groups and amide groups.
  • a copolymer comprising at least one functional group selected from the group consisting of OH groups and COOH groups as the first functional group and at least one functional group selected from the group consisting of amine groups and amide groups as the second functional group, Uniform coatings with harmonically improved dispersibility can be provided to provide prevention of coating layer detachment and electrochemical stability.
  • the acrylic copolymer may have a repeating unit derived from a monomer having a first functional group and a repeating unit derived from a monomer having a second functional group.
  • Non-limiting examples of the monomer having the first functional group include (meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy Butyric acid, acrylic acid duplex, itaconic acid, maleic acid, maleic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate and 2-hydroxypropylene glycol (meth) acrylate selected from the group consisting of It may be one or more.
  • the monomer having the second functional group may include at least one of an amine group and an amide group in a side chain thereof, and non-limiting examples thereof include 2-(((butoxyamino) carbonyl) oxy) ethyl (meth) Acrylate, 2- (diethylamino) ethyl (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, 3- (diethylamino) propyl (meth) acrylate, 3- (dimethylamino) Propyl (meth) acrylate, methyl 2-acetoamido (meth) acrylate, 2- (meth) acrylamidoglycolic acid, 2- (meth) acrylamido-2-methyl-1-propanesulfonic acid, ( 3- (meth) acrylamidopropyl) trimethyl ammonium chloride, N- (meth) acryloyl amido-ethoxyethanol, 3- (meth) acrylo
  • acrylic copolymers examples include ethyl acrylate-acrylic acid-N, N-dimethylacrylamide copolymer, ethyl acrylate-acrylic acid-2- (dimethylamino) ethyl acrylate copolymer, ethyl acrylate-acrylic acid-N, N And one or more selected from the group consisting of -diethylacrylamide copolymer and ethyl acrylate-acrylic acid-2- (diethylamino) ethyl acrylate copolymer.
  • the content of the dispersant may be 0.5 to 5 parts by weight based on 100 parts by weight of the inorganic particles.
  • the binder includes binder B and binder A, wherein binder B and binder A both include vinylidene fluoride (VDF) derived units and hexafluoropropylene (HFP) derived units, and the HFP derived units are represented by 8 To 50% by weight, preferably 8 to 40% by weight, more preferably 8 to 30% by weight, even more preferably 8 to 20% by weight, most preferably 10 to 15% by weight, and in binder A, It is 80% or less of the ratio of binder B and 5% by weight or more of binder A, and the total number average molecular weight of binder B is 200,000 to 2 million, preferably 300,000 to 1.5 million, and even more preferably 400,000 to 120.
  • VDF vinylidene fluoride
  • HFP hexafluoropropylene
  • the total number average molecular weight of binder A is 70% or less of binder B, and the weight ratio of binder A: binder B in the total coating composition is 0.1 to 10: 1, preferably 0.3 Not 8: 1, more preferably 0.5 to 6: 1, even more preferably 0.7 to 4: 1, most preferably from 0.8 to 2: 1 in a coating composition.
  • the content of binder A is lower than the above range, it is dried before phase separation to obtain sufficient electrode adhesion. If the content of binder A is high, the adhesion is sharp at 3 ⁇ m, which is high in electrical resistance or thin coating thickness. There is a problem falling.
  • Vinylidene fluoride-derived copolymer including poly (vinylidene fluoride-co-chlorotrifluoroethylene, poly (vinylidene fluoride-co-trifluoroethylene), etc., in addition to binder B and binder A, polymethylmetha Polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylene-co-vinyl acetate, polyethylene oxide, Cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethyl Cellulose (cyanoethylcellulose), cyanoethyl sucrose (cyanoethylsucrose), Pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer, polyimide, or a mixture of two
  • the content of the binder may be 3 to 50 parts by weight based on 100 parts by weight of the inorganic particles.
  • Coating method of the coating composition according to the present invention comprises the steps of forming a binder solution; Forming a coating slurry; It consists of forming a porous coating layer.
  • the slurry formed in the coating slurry forming step is applied to at least one surface of the porous substrate to form a porous coating layer.
  • Porous substrates can be used as previously described herein for separators.
  • the method of coating the slurry on which the inorganic particles are dispersed on the porous substrate may use a conventional coating method known in the art, for example, dip coating, die coating, roll coating, comma Various methods can be used, such as a (comma) coating or a mixing method thereof.
  • the porous coating layer may be selectively formed only on both sides or one side of the porous substrate.
  • the coating process is preferably carried out at a certain range of humidity.
  • binder A and binder B according to the present invention dissolved in the coating layer (slurry) during the drying process are different phase transitions by vapor-induced phase separation phenomenon known in the art. Will have characteristics.
  • the non-solvent (e.g., moisture or vapor) phase transition rate is higher with higher HFP content, resulting in lower phase separation rates under the same nonsolvent, and the amount of nonsolvent required for phase separation is also relatively high. You will need a lot.
  • binder A having a low HFP content is phase-transformed by a relatively small amount of non-solvent and has a high speed, thereby distributing more structures than binder B on the surface of the resulting porous coating layer, thereby forming a structure of an adhesive layer, and relatively HFP content.
  • This high binder B is required to have a large amount of non-solvent required for phase separation and is relatively slow, and thus is present in the inside of the porous coating layer more than binder A. Therefore, according to one embodiment of the present invention, a structurally stable porous coating layer and a binder layer having excellent adhesion to the electrode is formed on the porous coating layer.
  • the weight ratio of HFP in binder A is 80% or less of binder B, it may have a distribution tendency of a desired binder as described above.
  • the binder A having a low HFP content is even lower than the number average molecular weight of the binder B, so that the phase transition may occur rapidly even at a short drying time of the thin film coating having a thickness of 3 ⁇ m or less, and the speed may be faster.
  • the number average molecular weight of the binder A is 70% or less of the binder B, the desired physical properties can be obtained even when the thickness is 3 ⁇ m or less and the thin film and the low humidity.
  • Drying can use methods known in the art and can be carried out batchwise or continuously using an oven or heated chamber in a temperature range that takes into account the vapor pressure of the solvent used.
  • the drying is to almost eliminate the solvent present in the slurry, which is preferably as fast as possible in view of productivity and the like, for example, may be carried out for a time of 1 minute or less, preferably 30 seconds or less.
  • the separator of the present invention prepared by the above-described manufacturing method can be used as the separator of the electrochemical device.
  • the separator according to an embodiment of the present invention may be usefully used as the separator interposed between the positive electrode and the negative electrode.
  • Electrochemical devices include all devices that undergo an electrochemical reaction, and specific examples include capacitors such as all kinds of primary cells, secondary batteries, fuel cells, solar cells, or supercapacitor devices.
  • a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the secondary batteries is preferable.
  • the electrochemical device may be manufactured according to a conventional method known in the art, for example, it may be manufactured by injecting an electrolyte after assembling through the above-described separator between the positive electrode and the negative electrode.
  • the electrode to be applied together with the separator according to an embodiment of the present invention is not particularly limited, and according to a conventional method known in the art, the electrode active material may be prepared in a form bound to the electrode current collector.
  • the positive electrode active material of the electrode active material may be used a conventional positive electrode active material that can be used for the positive electrode of the conventional electrochemical device, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide or a combination thereof It is preferable to use one lithium composite oxide.
  • Non-limiting examples of the negative electrode active material may be a conventional negative electrode active material that can be used for the negative electrode of the conventional electrochemical device, in particular lithium metal or lithium alloy, carbon, petroleum coke, activated carbon, Lithium adsorbents such as graphite or other carbons are preferred.
  • Non-limiting examples of the positive electrode current collector is a foil produced by aluminum, nickel or a combination thereof, and non-limiting examples of the negative electrode current collector is produced by copper, gold, nickel or copper alloy or a combination thereof Foil and the like.
  • the electrolyte solution which can be used in one embodiment of the present invention is a salt having a structure such as A + B-,
  • a + includes an ion consisting of an alkali metal cation such as Li + , Na + , K + or a combination thereof
  • B - is PF 6 -, BF 4 -, Cl -, Br -, I -, ClO 4 -, AsF 6, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -
  • C Salts containing ions consisting of anions such as (CF 2 SO 2 ) 3 - or a combination thereof are propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl Carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrroli
  • the injection of the electrolyte may be performed at an appropriate stage of the battery manufacturing process, depending on the manufacturing process and the required physical properties of the final product.
  • Example binders according to the present invention and the binder solutions of Comparative Examples 1 and 2 were prepared as follows.
  • Binder A PVDF-HFP, molecular weight 400,000, HFP content 8%
  • Binder B PVDF-HFP, molecular weight 900,000, HFP content 14%
  • the mixed weight ratio of binder A and binder B is 1: 1
  • Binder A and B were mixed in a 1: 1 weight ratio, added to acetone, and dissolved at 50 for about 4 hours to prepare a binder solution.
  • a slurry was prepared by adding cyanoethylpolyvinyl alcohol to 10 wt% of the total amount of PVDF-HFP binder and then crushing and dispersing the inorganic particles using a ball mill method for a total of 12 hours. At this time, the ratio of solvent and solid content was set to 4: 1.
  • Comparative Example 1 The slurry of Comparative Example 1 and Comparative Example 2 was prepared using the same method except for the binder.
  • Each slurry to which the binders of Example, Comparative Example 1 and Comparative Example 2 were applied was used to coat 3, 4 and 5 ⁇ based on the cross section at 45% humidity and 3 ⁇ based on the cross section at 35% humidity. It was.
  • the surface of the coatings of Examples, Comparative Examples 1 and 2 related to this were measured by electron microscope and shown in FIGS. 2, 3 and 4, respectively. 2 shows good coating even at 3 ⁇ m and humidity of 35%, and Comparative Example 2 did not show satisfactory coating results under all conditions.
  • Example 1 only low-humidity, 3 ⁇ m thin film coatings showed similar physical properties, Comparative Examples 1 and 2 showed a problem showing a sharp drop in adhesion. Comparative Example 2 exhibited a problem that not only the adhesion was too low overall, but also decreased further in the thin film coating.
  • the present invention increases the bonding force between the porous coating layer and the electrode of the separator to increase the safety due to the strong integration of the separator and the electrode and to suppress the increase in the interfacial resistance of the separator and the electrode by the electrode side reaction generated during the cycle, improving the air permeability binder It can provide a coating composition comprising a.
  • a coating composition capable of sufficient phase separation even under low humidity conditions is provided. .

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Cell Separators (AREA)

Abstract

La présente invention concerne une composition de revêtement, comprenant un solvant, des particules inorganiques, un dispersant et un liant, permettant de revêtir au moins une surface d'un substrat poreux comportant une pluralité de pores. Le liant comprend un liant B et un liant A, le liant B et le liant A contenant tous deux une unité dérivée de fluorure de vinylidène (VDF) et une unité dérivée d'hexafluoropropylène (HFP). L'unité dérivée de HFP représente 8 % à 50 % en poids du liant B, et dans le liant A, l'unité dérivée de HFP n'est pas supérieure à 80 % de sa proportion dans le liant B et n'est pas inférieure à 5 % en poids du liant A. Le poids moléculaire moyen en nombre total du liant B est de 200 000 à 2 000 000, et le poids moléculaire moyen en nombre total du liant A est de 70 % ou moins de celui du liant B. Le rapport en poids du liant A au liant B dans la composition de revêtement totale est de 0,1 à 10 pour 1. La présente invention a résolu le problème selon lequel, lorsqu'un liant est aminci de 4 µm à 3 µm, le liant sèche avant d'être suffisamment séparé en phase et donc une force d'adhérence d'électrode suffisante ne peut pas être obtenue, et également en termes de procédé de fabrication, la présente invention a fourni une composition de revêtement dans laquelle une séparation de phase suffisante se produit même dans des conditions de faible humidité.
PCT/KR2018/001907 2017-02-13 2018-02-13 Film de séparation pour batterie secondaire au lithium à couche adhésive WO2018147714A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
EP18751649.7A EP3518318B1 (fr) 2017-02-13 2018-02-13 Film de séparation pour batterie secondaire au lithium à couche adhésive
JP2019528486A JP6824559B2 (ja) 2017-02-13 2018-02-13 接着層を備えたリチウム二次電池用分離膜
CN201880004178.XA CN110249447B (zh) 2017-02-13 2018-02-13 包括粘合剂层的锂二次电池隔板
PL18751649.7T PL3518318T3 (pl) 2017-02-13 2018-02-13 Folia separująca do litowej baterii akumulatorowej mająca warstwę klejącą
US16/341,805 US11721873B2 (en) 2017-02-13 2018-02-13 Lithium secondary battery separator including adhesive layer
ES18751649T ES2969212T3 (es) 2017-02-13 2018-02-13 Película de separación para batería secundaria de litio que tiene una capa adhesiva

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KR20170019606 2017-02-13
KR10-2017-0019606 2017-02-13
KR1020180018027A KR102311624B1 (ko) 2017-02-13 2018-02-13 접착층을 구비한 리튬 이차전지용 분리막
KR10-2018-0018027 2018-02-13

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110358402A (zh) * 2019-05-29 2019-10-22 江苏科技大学 一种用于制备埋入式电容的复合薄膜浆料、制法及用其制备埋入式电容的方法
WO2020101363A1 (fr) * 2018-11-14 2020-05-22 주식회사 엘지화학 Séparateur pour batterie rechargeable au lithium et son procédé de fabrication
CN112385076A (zh) * 2018-10-29 2021-02-19 株式会社Lg化学 用于电化学装置的隔板和制造该隔板的方法
CN112424991A (zh) * 2018-09-28 2021-02-26 株式会社Lg化学 用于电化学装置的隔板和制造该隔板的方法
CN113261153A (zh) * 2019-01-04 2021-08-13 三星Sdi株式会社 用于锂二次电池的隔板及包括该隔板的锂二次电池
EP3800700A4 (fr) * 2018-12-21 2021-09-01 Lg Chem, Ltd. Séparateur pour dispositif électrochimique et dispositif électrochimique le contenant
CN113812037A (zh) * 2019-06-14 2021-12-17 株式会社Lg新能源 制造隔膜的方法以及由此制造的隔膜
JP2023500544A (ja) * 2019-11-19 2023-01-06 エルジー エナジー ソリューション リミテッド 電気化学素子用分離膜及びそれを含む電気化学素子
US12136743B2 (en) 2018-12-26 2024-11-05 Samsung Sdi Co., Ltd. Separator for lithium secondary battery, and lithium secondary battery comprising same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013161707A (ja) * 2012-02-07 2013-08-19 Teijin Ltd 非水系二次電池用セパレータおよび非水系二次電池
KR20140050877A (ko) * 2012-10-22 2014-04-30 주식회사 엘지화학 바인더층을 갖는 분리막, 상기 분리막을 포함하는 전기화학소자, 및 상기 분리막의 제조방법
KR20140147742A (ko) * 2013-06-19 2014-12-30 주식회사 엘지화학 바인더 수지 조성물, 그를 포함하는 다공성 분리막 및 그를 이용한 전기 화학 소자
KR20160081766A (ko) * 2015-08-06 2016-07-08 삼성에스디아이 주식회사 다공성 내열층 조성물, 다공성 내열층을 포함하는 분리막, 상기 분리막을 이용한 전기 화학 전지, 및 상기 분리막의 제조 방법
KR20160117962A (ko) * 2015-04-01 2016-10-11 삼성에스디아이 주식회사 접착층을 포함하는 분리막 및 이를 이용한 이차 전지

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013161707A (ja) * 2012-02-07 2013-08-19 Teijin Ltd 非水系二次電池用セパレータおよび非水系二次電池
KR20140050877A (ko) * 2012-10-22 2014-04-30 주식회사 엘지화학 바인더층을 갖는 분리막, 상기 분리막을 포함하는 전기화학소자, 및 상기 분리막의 제조방법
KR20140147742A (ko) * 2013-06-19 2014-12-30 주식회사 엘지화학 바인더 수지 조성물, 그를 포함하는 다공성 분리막 및 그를 이용한 전기 화학 소자
KR20160117962A (ko) * 2015-04-01 2016-10-11 삼성에스디아이 주식회사 접착층을 포함하는 분리막 및 이를 이용한 이차 전지
KR20160081766A (ko) * 2015-08-06 2016-07-08 삼성에스디아이 주식회사 다공성 내열층 조성물, 다공성 내열층을 포함하는 분리막, 상기 분리막을 이용한 전기 화학 전지, 및 상기 분리막의 제조 방법

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3518318A4 *

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112424991A (zh) * 2018-09-28 2021-02-26 株式会社Lg化学 用于电化学装置的隔板和制造该隔板的方法
JP2021528813A (ja) * 2018-09-28 2021-10-21 エルジー・ケム・リミテッド 電気化学素子用分離膜及びこれを製造する方法
US11990642B2 (en) 2018-09-28 2024-05-21 Lg Energy Solution, Ltd. Separator for electrochemical device and method for manufacturing the same
JP7374134B2 (ja) 2018-09-28 2023-11-06 エルジー エナジー ソリューション リミテッド 電気化学素子用分離膜及びこれを製造する方法
CN112424991B (zh) * 2018-09-28 2023-09-19 株式会社Lg新能源 用于电化学装置的隔板和制造该隔板的方法
CN112385076A (zh) * 2018-10-29 2021-02-19 株式会社Lg化学 用于电化学装置的隔板和制造该隔板的方法
WO2020101363A1 (fr) * 2018-11-14 2020-05-22 주식회사 엘지화학 Séparateur pour batterie rechargeable au lithium et son procédé de fabrication
EP3800700A4 (fr) * 2018-12-21 2021-09-01 Lg Chem, Ltd. Séparateur pour dispositif électrochimique et dispositif électrochimique le contenant
US11967731B2 (en) 2018-12-21 2024-04-23 Lg Energy Solution, Ltd. Separator for electrochemical device and electrochemical device containing same
US12136743B2 (en) 2018-12-26 2024-11-05 Samsung Sdi Co., Ltd. Separator for lithium secondary battery, and lithium secondary battery comprising same
CN113261153B (zh) * 2019-01-04 2023-10-20 三星Sdi株式会社 用于锂二次电池的隔板及包括该隔板的锂二次电池
CN113261153A (zh) * 2019-01-04 2021-08-13 三星Sdi株式会社 用于锂二次电池的隔板及包括该隔板的锂二次电池
CN110358402B (zh) * 2019-05-29 2021-07-27 江苏科技大学 一种用于制备埋入式电容的复合薄膜浆料、制法及用其制备埋入式电容的方法
CN110358402A (zh) * 2019-05-29 2019-10-22 江苏科技大学 一种用于制备埋入式电容的复合薄膜浆料、制法及用其制备埋入式电容的方法
CN113812037B (zh) * 2019-06-14 2023-08-15 株式会社Lg新能源 制造隔膜的方法以及由此制造的隔膜
CN113812037A (zh) * 2019-06-14 2021-12-17 株式会社Lg新能源 制造隔膜的方法以及由此制造的隔膜
JP7395213B2 (ja) 2019-11-19 2023-12-11 エルジー エナジー ソリューション リミテッド 電気化学素子用分離膜及びそれを含む電気化学素子
JP2023500544A (ja) * 2019-11-19 2023-01-06 エルジー エナジー ソリューション リミテッド 電気化学素子用分離膜及びそれを含む電気化学素子

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