WO2018209794A1 - Composition polymère pour la formation d'une membrane isolante pour batterie, membrane isolante pour batterie et son procédé de préparation - Google Patents

Composition polymère pour la formation d'une membrane isolante pour batterie, membrane isolante pour batterie et son procédé de préparation Download PDF

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WO2018209794A1
WO2018209794A1 PCT/CN2017/093654 CN2017093654W WO2018209794A1 WO 2018209794 A1 WO2018209794 A1 WO 2018209794A1 CN 2017093654 W CN2017093654 W CN 2017093654W WO 2018209794 A1 WO2018209794 A1 WO 2018209794A1
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battery separator
molecular weight
polymer composition
forming
ribbon
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PCT/CN2017/093654
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English (en)
Chinese (zh)
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程跃
熊磊
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上海恩捷新材料科技股份有限公司
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/005—Stabilisers against oxidation, heat, light, ozone
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C69/00—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore
    • B29C69/02—Combinations of shaping techniques not provided for in a single one of main groups B29C39/00 - B29C67/00, e.g. associations of moulding and joining techniques; Apparatus therefore of moulding techniques only
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/04—Homopolymers or copolymers of ethene
    • C08L23/06—Polyethene
    • 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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H01M50/406—Moulding; Embossing; Cutting
    • 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
    • H01M50/491—Porosity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2007/00—Flat articles, e.g. films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/04—Homopolymers or copolymers of ethene
    • C08J2323/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2423/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2423/04—Homopolymers or copolymers of ethene
    • C08J2423/06—Polyethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/14—Applications used for foams
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/16—Applications used for films
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/20—Applications use in electrical or conductive gadgets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2207/00—Properties characterising the ingredient of the composition
    • C08L2207/06—Properties of polyethylene
    • C08L2207/068—Ultra high molecular weight polyethylene
    • 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 the field of lithium battery technology, and in particular to a polymer composition for forming a battery separator, a battery separator, and a preparation method.
  • Lithium-ion batteries are usually composed mainly of a positive electrode, a negative electrode, a separator, an electrolyte, and a battery casing.
  • the diaphragm is one of the key inner layer components.
  • the main function of the separator is to separate the positive and negative electrodes of the battery to prevent direct contact between the positive and negative electrodes and short circuit.
  • the electrolyte ions can pass smoothly during the charging and discharging process of the battery to form a current, and the battery operating temperature is abnormal. When rising, the electrolyte ion migration channel is turned off, and the current is cut off to ensure battery safety.
  • the performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle and safety performance of the battery.
  • the separator with excellent performance plays an important role in improving the overall performance of the battery.
  • commercially available lithium ion battery separators generally employ a polyolefin porous membrane.
  • the main performance parameters of the battery separator include thickness, porosity, pore size, pore size distribution, strength, heat shrinkage, closed cell temperature and membrane rupture temperature.
  • the electrode area In order to reduce the internal resistance of the battery, the electrode area must be as large as possible, so the thickness of the diaphragm is required to be as thin as possible.
  • the battery separator itself is not electrically conductive, the conductive ions need to migrate through the diaphragm. This requires that the diaphragm itself needs a certain number of pores, that is, porosity, but the porosity is too high, which will cause the strength of the diaphragm to decrease, affecting the overall reliability of the battery.
  • the wettability of the electrolyte on the separator directly affects the resistance of ion migration.
  • the pore diameter is not very large, the more uniform the pore size distribution, the better the wettability of the electrolyte.
  • the battery assembly needs to pull the diaphragm during its production and assembly process. After the assembly is completed, it is also necessary to ensure that the diaphragm is not pierced by the electrode material, so the diaphragm not only needs sufficient tensile strength but also requires a certain piercing strength.
  • the polymer separator will undergo heat shrinkage under certain heating conditions.
  • the heat shrinkage rate of the separator is also required.
  • the internal temperature of the battery rises sharply due to excessive current, which requires the diaphragm to close the migration path of the conductive ions in time. Therefore, the temperature at which the micropores of the battery separator are melt-closed is referred to as a closed-cell temperature.
  • the isolation film is broken and the fracture temperature is called the film breaking temperature.
  • the closed-cell temperature and the membrane-breaking temperature of the diaphragm must have a certain temperature difference to ensure that even if the temperature continues to rise after the diaphragm is closed, the diaphragm will not rupture.
  • the conventional wet lithium ion battery separator needs to undergo an organic solvent extraction process in the production process, which is often a bottleneck restricting the production speed of the entire battery separator film, and there is also a significant gap between the two sides of the produced separator. Same In order to maintain the continuity of the entire production process, all heating components require external heat supply, high energy consumption and high production costs.
  • An object of the present invention is to provide a semi-dry and semi-wet battery separator manufacturing process and a product thereof, which can eliminate the extraction process in the wet process, and at the same time, the battery separator has excellent comprehensive performance, such as The lower micropore diameter, uniform concentration of pore size distribution, good porosity and film strength, the two sides of the separator prepared by this method have a closer microscopic morphology.
  • an object of the present invention is to provide a polymer composition, a battery separator, and a preparation method for forming a battery separator, which are used for solving a battery separator prepared by a wet process in the prior art.
  • the resulting micro-topography of the battery separator has significant differences, and in order to maintain the continuity of the entire production process, all heating components require external heat supply. The problem of high energy consumption and high production cost.
  • the present invention provides a polymer composition for forming a battery separator, the polymer composition forming the battery separator comprising: an average molecular weight of 1.0 ⁇ 10 5 to 10.0 ⁇ 10 6 and a high molecular weight polyethylene having a density of 0.940 to 0.976 g/cm 3 , a pore former, and an antioxidant, wherein
  • the pore former has a weight of 500 to 2000 parts by weight based on 100 parts by weight of the high molecular weight polyethylene, and the antioxidant has a weight of 0.1 to 10 parts.
  • the pore former comprises: natural mineral oil, C 6-15 alkane, C 8-15 aliphatic carboxylic acid C 1-4 alkyl ester , C 2-6 halogenated alkane, phthalate, trimellitate, adipate, sebacate, maleate, benzoate, epoxy vegetable oil, benzenesulfonamide, phosphoric acid At least one of a triester, a glycol ether, acetyl glyceryl monoacetate, a citric acid ester or a diisononyl cyclohexane-1,2-dicarboxylate.
  • the pore former has a kinematic viscosity at 40 ° C of 10 mm 2 /s to 100 mm 2 /s.
  • the pore former has an initial boiling point of greater than or equal to 110 °C.
  • the antioxidant comprises: 4,4-thiobis(6-tert-butylm-cresol), dibutylhydroxytoluene, sub- Phosphate ester, tert-butyl hydroquinone, ⁇ -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl carbonate, 1,1,3-tris(2-methyl-) 4-hydroxy-5-tert-butylphenyl)butane, 2-tert-butyl-6-methylphenol, N,N'-di- ⁇ -naphthyl p-phenylenediamine, dilauryl thiodipropionate, At least one of tris(nonylphenyl)phosphite or triphenyl phosphite.
  • the invention also provides a method for preparing a battery separator, the method for preparing the battery separator comprises:
  • step 1) the continuously extruded polymer composition is subjected to vacuum distillation to cast the cast piece to obtain a ribbon;
  • the strip obtained in the step 2) is subjected to vacuum distillation to biaxially stretch into a film to remove the pore former in the ribbon;
  • the step 1) comprises the following steps:
  • the high molecular weight polyethylene having an average molecular weight of 1.0 ⁇ 10 5 to 10.0 ⁇ 10 6 and a density of 0.940 to 0.976 g/cm 3 , the pore former and the antioxidant in a desired mass part Add into the continuous ingredient feeding kettle, stir and mix evenly;
  • step 1-1) adding the mixture obtained in the step 1-1) to the extruder, the high molecular weight polyethylene having an average molecular weight of 1.0 ⁇ 10 5 to 10.0 ⁇ 10 6 and a density of 0.940 to 0.976 g/cm 3 and The antioxidant is dissolved in the porogen and is continuously extruded from the extruder.
  • the step 2) comprises the following steps:
  • step 1) placing the polymer composition continuously extruded in step 1) into a slit die in a vacuum distillation chamber;
  • the polymer composition was extruded through a slit die onto a casting chill roll and cast into a ribbon at a casting temperature.
  • the ribbon obtained in the step 2) is subjected to vacuum distillation to biaxially stretch into a film to remove the pore former in the ribbon.
  • the specific method is as follows: the ribbon obtained in the step 2) is placed in a vacuum distillation chamber for vacuum distillation, and simultaneously fed to a biaxial stretching machine to stretch the ribbon.
  • the heat setting temperature is 100 to 150 ° C; and the heat setting time is 10 to 20 minutes.
  • the present invention also provides a battery separator obtained by the production method as described in any of the above schemes.
  • the battery separator has a thickness of 5 to 30 ⁇ m, a pore diameter of 0.3 to 0.8 ⁇ m, and a porosity of 30% to 60%.
  • the polymer separator, battery separator, and preparation method for forming a battery separator of the present invention have the following beneficial effects:
  • the battery separator forming polymer composition of the present invention is used to form a battery separator, using the polymer composition
  • the formed battery separator has a lower micropore diameter, a uniformly concentrated pore size distribution, a good porosity and a film strength, and the formed battery separator has a closer microscopic morphology on both sides;
  • the preparation method of the battery separator of the invention completely abandons the extraction process in the existing wet process, effectively breaks the bottleneck of the production speed of the existing battery separator, and the battery separator prepared by the method has excellent comprehensive performance:
  • the invention has a lower micropore diameter, a uniformly concentrated pore size distribution, a good porosity and a film strength.
  • the battery separator formed by the battery separator prepared by the method has a closer microscopic morphology on both sides.
  • the method for preparing a battery separator of the present invention has the advantages of low energy consumption and low production cost compared to the wet process in the prior art.
  • FIG. 1 is a flow chart showing a method of preparing a battery separator provided by the present invention.
  • Example 2 is a front and back photomicrograph of a battery separator prepared in Example 1 of the present invention, wherein a is a frontal photomicrograph and b is a reverse photomicrograph.
  • Example 3 is a front and back photomicrograph of a battery separator prepared in Example 2 of the present invention, wherein a is a frontal photomicrograph and b is a reverse photomicrograph.
  • Example 4 is a front and back photomicrograph of a battery separator prepared in Example 3 of the present invention, wherein a is a frontal photomicrograph and b is a reverse photomicrograph.
  • Figure 5 is a front and back photomicrograph of a battery separator prepared in Example 4 of the present invention, wherein a is a frontal photomicrograph and b is a reverse photomicrograph.
  • Figure 6 is a front and back photomicrograph of a battery separator prepared in Example 5 of the present invention, wherein a is a frontal photomicrograph and b is a reverse photomicrograph.
  • Figure 7 is a front and back photomicrograph of a battery separator prepared in Example 6 of the present invention, wherein a is a frontal photomicrograph and b is a reverse photomicrograph.
  • the present invention provides a polymer composition for forming a battery separator for preparing a battery separator, the polymer composition forming the battery separator comprising: an average molecular weight of 1.0 ⁇ 10 5 to 10.0 ⁇ 10 6 Daltons and a density of 0.940 ⁇ 0.976g / cm 3 of the high molecular weight polyethylene, an antioxidant porogen, wherein
  • the pore former has a weight of 500 to 2000 parts by weight based on 100 parts by weight of the high molecular weight polyethylene, and the antioxidant has a weight of 0.1 to 10 parts.
  • the high molecular weight polyethylene has an average molecular weight of 1.0 ⁇ 10 5 to 5.0 ⁇ 10 6 Daltons; more preferably, the high molecular weight polyethylene has an average molecular weight of 1.0 ⁇ 10 5 to 2.0 ⁇ 10 6 Dalton.
  • the high molecular weight polyethylene has a density of from 0.940 to 0.966 g/cm 3 ; more preferably, the high molecular weight polyethylene has a density of from 0.950 to 0.966 g/cm 3 .
  • the high molecular weight polyethylene may be a high molecular weight polyethylene having an average molecular weight or a mixture of two or more average molecular weight high molecular weight polyethylene.
  • the pore former may comprise: natural mineral oil, C 6-15 alkane, C 8-15 aliphatic carboxylic acid C 1-4 alkyl ester, C 2-6 halogenated alkane, phthalate, Trimellitic acid ester, adipate, sebacate, maleate, benzoate, epoxy vegetable oil, benzenesulfonamide, phosphotriester, glycol ether, acetyl monoglyceride, At least one of a citrate or a diisononyl cyclohexane-1,2-dicarboxylate.
  • the natural mineral oil may include CAS: 8020-83-5, 8042-47-5; MDL: MFCD00131611; E1NECS: 232-455-8, and the like.
  • the C 6-15 alkane may include decalin, decane, undecane or dodecane, and the like.
  • the C 8-15 aliphatic carboxylic acid C 1-4 alkyl ester may include methyl decanoate, ethyl decanoate, propyl citrate, n-butyl decanoate, methyl undecanoate, eleven Ethyl carbonate, propyl undecacrylate, n-butyl undecanoate, methyl dodecyl carbonate, ethyl dodecyl carbonate, propyl dodecyl carbonate or n-butyl dodecyl carbonate.
  • the C 2-6 haloalkane may include dichloroethane, dichloropropane, fluorochloroethane or chlorofluoropropane, and the like.
  • the pore former has a kinematic viscosity at 40 ° C of 10 mm 2 /s to 100 mm 2 /s; preferably, the pore former has a kinematic viscosity at 40 ° C of 20 mm 2 /s to 80 mm 2 /s; more preferably The pore former has a kinematic viscosity at 40 ° C of 30 mm 2 /s to 70 mm 2 /s.
  • the porogen has an initial boiling point greater than or equal to 110 °C.
  • the pore former has a weight of 700 to 1800 parts by weight of the high molecular weight polyethylene, and more preferably, the weight of the high molecular weight polyethylene is 100 parts.
  • the pore former has a weight of 800 to 1600 parts.
  • the antioxidant may include: 4,4-thiobis(6-tert-butylm-cresol), dibutylhydroxytoluene, phosphite, tert-butyl hydroquinone, ⁇ -(3 , 5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl carbonate, 1,1,3-tris(2-methyl-4hydroxy-5-tert-butylphenyl)butane, 2- Tert-butyl-6-methylphenol, N,N'-di- ⁇ -naphthyl p-phenylenediamine, dilauryl thiodipropionate, tris(nonylphenyl) phosphite or triphenyl phosphite At least one of the esters.
  • 4,4-thiobis(6-tert-butylm-cresol) dibutylhydroxytoluene
  • phosphite
  • the antioxidant has a weight of 0.5 to 8 parts by weight based on 100 parts by weight of the high molecular weight polyethylene; more preferably, the weight of the high molecular weight polyethylene is 100 parts, The antioxidant has a weight of 1 to 6 parts.
  • the present invention also provides a method for preparing a battery separator, and the method for preparing the battery separator includes:
  • step 1) the continuously extruded polymer composition is subjected to vacuum distillation to cast the cast piece to obtain a ribbon;
  • the strip obtained in the step 2) is subjected to vacuum distillation to biaxially stretch into a film to remove the pore former in the ribbon;
  • step 1) referring to step S1 in Figure 1, a polymer composition as described in any of the above schemes is prepared and the polymer composition is continuously extruded.
  • composition and characteristics of the polymer composition are described in detail above with respect to the contents of the polymer composition, and are not described herein.
  • preparing the polymer composition and continuously extruding the polymer composition comprises the steps of:
  • the stirring speed can be set according to actual needs.
  • the stirring speed can be 50 rpm; of course, in other examples, the stirring speed can also be other Any value;
  • the oxidant is dissolved in the porogen, it is continuously extruded by the extruder; the speed of continuous extrusion of the extruder can be set according to actual needs, and in an example, the extruder is continuously extruded
  • the speed of the exit may be 200 rpm; of course, in other examples, the speed at which the extruder is continuously extruded may also be any other value.
  • the extruder may be a single screw extruder, a twin screw extruder or a multi-screw extruder, or may be any other existing extruder.
  • step 2) referring to step S2 in Fig. 1, the polymer composition continuously extruded in step 1) is subjected to vacuum distillation casting to obtain a ribbon.
  • performing the step 1) continuous extrusion of the polymer composition by vacuum distillation casting the cast sheet comprises the following steps:
  • step 1) placing the polymer composition continuously extruded in step 1) into a slit die in a vacuum distillation chamber;
  • the polymer composition was extruded through a slit die onto a casting chill roll and cast into a ribbon at a casting temperature.
  • the casting temperature may be 50 to 100 ° C.
  • the casting temperature is 80 ° C.
  • step 3 referring to the step S3 in FIG. 1, the ribbon obtained in the step 2) is biaxially drawn into a film by vacuum distillation to remove the pore former in the ribbon. .
  • the strip obtained in the step 2) is subjected to vacuum distillation biaxially to form a film
  • the specific method for removing the pore former in the ribbon is: the step obtained in the step 2)
  • the ribbon is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine to stretch the ribbon to obtain a film from which the pore former is removed.
  • step 4 referring to step S4 in Fig. 1, the film obtained in step 3) is heat set.
  • the heat setting temperature and heat setting time can be set according to actual needs; preferably, the heat setting temperature is 100 to 150 ° C; the heat setting time is 10 to 20 minutes; more preferably, the heat setting temperature is It is 120 ° C; the heat setting time is 15 minutes.
  • step 5 referring to step S5 in Fig. 1, the heat-set film is wound up.
  • the heat-set film is placed in a winding device to be wound up to obtain the battery separator, which is a semi-dry and semi-wet battery separator.
  • the speed at which the heat-set film is wound may be set according to actual needs.
  • the speed of winding the heat-set film may be 20 to 100 m/min; more preferably, The heat-set film was wound at a speed of 50 m/min.
  • the above preparation method of the battery separator completely eliminates the extraction process in the existing wet process, effectively breaks the bottleneck of the production speed of the existing battery separator, and the battery separator prepared by the method has excellent comprehensive performance: for example, It has a low pore size, a uniform concentration of pore size distribution, good porosity and film strength. At the same time, the battery separator formed by the battery separator has a closer microscopic morphology on both sides.
  • the method for preparing a battery separator of the present invention has the advantages of low energy consumption and low production cost compared to the wet process in the prior art.
  • test instruments and test methods used in each performance test are first described as follows:
  • German Malt film thickness gauge 1216 was measured according to the method for measuring the thickness of plastic film and sheet of GB/T6672-2001.
  • results were measured using a multimeter at two points where the separators were 10 cm apart, and the results were the average of 10 measurements at different measurement points.
  • Gurley permeability tester 4110 was used to measure according to the GB/T 1037 plastic film and sheet water vapor permeability test method.
  • the Shanghai Jiaoji QJ210A universal testing machine was used to measure the peeling strength of the paper according to GB/T 2679.7.
  • test was carried out according to ASTM d882-2002 tensile standard test method for plastic sheets using a Shanghai TQ QJ210A universal testing machine.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the substance is placed in a vacuum distillation chamber for distillation under reduced pressure. At the same time, it is fed into a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • FIG. 2 A photomicrograph of the battery separator obtained in this example is shown in Fig. 2.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • FIG. 1 A photomicrograph of the battery separator obtained in this example is shown in FIG.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • FIG. 1 A photomicrograph of the battery separator obtained in this example is shown in FIG.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • FIG. 1 A photomicrograph of the battery separator obtained in this example is shown in FIG.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • FIG. 6 A photomicrograph of the battery separator obtained in this example is shown in Fig. 6.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • FIG. 1 A photomicrograph of the battery separator obtained in this example is shown in FIG.
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • the mixture was continuously fed into an extruder, and at 180 ° C, the high molecular weight polyethylene, the antioxidant was continuously dissolved in mineral oil in an extruder, and then continuously extruded by an extruder at a speed of 200 rpm. Out.
  • the continuously extruded mixture was introduced into a slit die placed in a vacuum distillation chamber, and the mixture was extruded through a slit die to a casting cooling roll, and cast into a ribbon at 80 ° C to obtain a belt.
  • the material is placed in a vacuum distillation chamber for distillation under reduced pressure, and simultaneously fed to a biaxial stretching machine for stretching to remove mineral oil from the ribbon.
  • the obtained film was heat-set at 120 ° C for 15 minutes, and the film was wound up at a speed of 50 m / min to finally obtain a semi-dry and semi-wet battery separator.
  • the battery separator obtained in the present embodiment was tested by the above test instrument and test method, and the test results are as follows:
  • the present invention also provides a battery separator obtained by the production method as described in any of the above schemes.
  • the battery separator has a thickness of 5 to 30 ⁇ m, a pore diameter of 0.3 to 0.8 ⁇ m, and a porosity of 30% to 60%.
  • the present invention provides a polymer composition for forming a battery separator, a battery separator, and a preparation method, the polymer composition for forming a battery separator comprising: an average molecular weight of 1.0 ⁇ 10 5 to 10.0 ⁇ 106 and a density of 0.940 ⁇ 0.976g / cm 3 of the high molecular weight polyethylene, an antioxidant porogen, wherein the high molecular weight polyethylene by weight of 100 parts of the weight of porogen 500 ⁇ 2000 parts, the antioxidant has a weight of 0.1 to 10 parts.
  • the polymer separator forming battery separator of the present invention is used for forming a battery separator, and the battery separator formed using the polymer composition has a low pore diameter, a uniformly concentrated pore size distribution, a good porosity, and Membrane strength, and the formed battery separator has more close microscopic morphology on both sides; the preparation method of the battery separator of the invention completely abandons the extraction process in the existing wet process, effectively breaks through the production of the existing battery separator
  • the bottleneck of speed, and the battery separator prepared by the method has excellent comprehensive properties: for example, having a low pore diameter, a uniformly concentrated pore size distribution, good porosity and film strength, and the battery isolation prepared by the method
  • the battery separator formed by the film has a closer microscopic morphology on both sides.
  • the method for producing a battery separator of the present invention has the advantages of low energy consumption and low production cost as compared with the wet process of the prior art.

Abstract

L'invention concerne une composition polymère pour la formation d'une membrane isolante pour batterie, une membrane isolante pour batterie et son procédé de préparation. La composition polymère pour la formation d'une membrane isolante pour batterie comprend : du polyéthylène de poids moléculaire élevé présentant un poids moléculaire moyen égal à 1,0 x 105 à 10,0 x 106 et une densité égale à 0,940 à 0,976 g/cm3, un agent porogène et un antioxydant. Si le polyéthylène de poids moléculaire élevé représente 100 parties en poids, l'agent porogène représente de 500 à 2 000 parties en poids et l'antioxydant de 0,1 à 10 parties en poids. La composition polymère pour la formation d'une membrane isolante pour batterie est utilisée pour former une membrane isolante pour batterie. La membrane isolante pour batterie formée en utilisant la présente composition polymère présente une faible ouverture des micro-pores, une distribution homogène et centralisée des ouvertures, une bonne porosité et une bonne résistance de la membrane, et les deux surfaces de la membrane isolante pour batterie formée présentent un aspect microscopique plus proche.
PCT/CN2017/093654 2017-05-15 2017-07-20 Composition polymère pour la formation d'une membrane isolante pour batterie, membrane isolante pour batterie et son procédé de préparation WO2018209794A1 (fr)

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CN107706342A (zh) * 2017-09-27 2018-02-16 上海恩捷新材料科技股份有限公司 电池隔离膜、锂离子电池及其制备方法
CN108192116B (zh) * 2017-12-29 2021-03-23 上海恩捷新材料科技有限公司 一种光引发交联聚合物隔离膜及其制备方法
CN108110194B (zh) * 2017-12-29 2021-09-10 上海恩捷新材料科技有限公司 一种过氧化物交联聚合物隔离膜及其制备方法
CN108619923A (zh) * 2018-05-04 2018-10-09 上海恩捷新材料科技股份有限公司 水处理多孔膜及其制备方法
CN113471626A (zh) * 2018-07-18 2021-10-01 河南义腾新能源科技有限公司 一种聚乙烯隔膜及其制备方法
CN109438803B (zh) * 2018-09-28 2022-03-29 上海恩捷新材料科技有限公司 聚合物隔离膜及制备方法
CN110286075A (zh) * 2019-06-12 2019-09-27 河北金力新能源科技股份有限公司 一种锂离子电池隔膜闭孔温度的测试方法
CN112169605A (zh) * 2020-09-15 2021-01-05 上海恩捷新材料科技有限公司 一种聚烯烃隔膜，电化学装置，聚烯烃隔膜原料的制备方法

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