WO2023273109A1 - Secondary battery, battery separator, and slurry for preparing coating of battery separator - Google Patents
Secondary battery, battery separator, and slurry for preparing coating of battery separator Download PDFInfo
- Publication number
- WO2023273109A1 WO2023273109A1 PCT/CN2021/131615 CN2021131615W WO2023273109A1 WO 2023273109 A1 WO2023273109 A1 WO 2023273109A1 CN 2021131615 W CN2021131615 W CN 2021131615W WO 2023273109 A1 WO2023273109 A1 WO 2023273109A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- battery separator
- monomer
- structural unit
- coating
- water
- Prior art date
Links
- 239000011248 coating agent Substances 0.000 title claims abstract description 57
- 238000000576 coating method Methods 0.000 title claims abstract description 57
- 239000002002 slurry Substances 0.000 title claims abstract description 22
- 239000000853 adhesive Substances 0.000 claims abstract description 19
- 230000001070 adhesive effect Effects 0.000 claims abstract description 19
- 229920000642 polymer Polymers 0.000 claims abstract description 18
- 239000000463 material Substances 0.000 claims abstract description 13
- 239000000178 monomer Substances 0.000 claims description 61
- 239000002245 particle Substances 0.000 claims description 32
- 239000000919 ceramic Substances 0.000 claims description 29
- 239000002270 dispersing agent Substances 0.000 claims description 24
- 229920003169 water-soluble polymer Polymers 0.000 claims description 18
- 239000011230 binding agent Substances 0.000 claims description 14
- 230000009477 glass transition Effects 0.000 claims description 13
- -1 polyethylene Polymers 0.000 claims description 13
- 239000011203 carbon fibre reinforced carbon Substances 0.000 claims description 12
- 125000000524 functional group Chemical group 0.000 claims description 12
- 229920001519 homopolymer Polymers 0.000 claims description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 8
- 239000004698 Polyethylene Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 8
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 8
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 8
- 229920000573 polyethylene Polymers 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 8
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 6
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 6
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 5
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 5
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 5
- 239000011837 N,N-methylenebisacrylamide Substances 0.000 claims description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 5
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical compound CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 claims description 5
- ZIUHHBKFKCYYJD-UHFFFAOYSA-N n,n'-methylenebisacrylamide Chemical compound C=CC(=O)NCNC(=O)C=C ZIUHHBKFKCYYJD-UHFFFAOYSA-N 0.000 claims description 5
- 229920000058 polyacrylate Polymers 0.000 claims description 5
- MUZDXNQOSGWMJJ-UHFFFAOYSA-N 2-methylprop-2-enoic acid;prop-2-enoic acid Chemical compound OC(=O)C=C.CC(=C)C(O)=O MUZDXNQOSGWMJJ-UHFFFAOYSA-N 0.000 claims description 4
- 239000004743 Polypropylene Substances 0.000 claims description 4
- 150000001408 amides Chemical class 0.000 claims description 4
- 229910001593 boehmite Inorganic materials 0.000 claims description 4
- 125000004185 ester group Chemical group 0.000 claims description 4
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 4
- 239000000395 magnesium oxide Substances 0.000 claims description 4
- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 claims description 4
- 229920001155 polypropylene Polymers 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 claims description 4
- 235000019982 sodium hexametaphosphate Nutrition 0.000 claims description 4
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical compound [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 claims description 4
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 claims description 4
- 238000007731 hot pressing Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 229920000098 polyolefin Polymers 0.000 description 4
- 238000010998 test method Methods 0.000 description 3
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 238000005524 ceramic coating Methods 0.000 description 2
- 239000006255 coating slurry Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000003999 initiator Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- FAVWXKQADKRESO-UHFFFAOYSA-N 2-methylprop-2-enoic acid;prop-1-ene Chemical compound CC=C.CC(=C)C(O)=O FAVWXKQADKRESO-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003995 emulsifying agent Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000007756 gravure coating Methods 0.000 description 1
- 229920001903 high density polyethylene Polymers 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- VXLYKKNIXGIKAE-UHFFFAOYSA-N prop-2-enoyl 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OC(=O)C=C VXLYKKNIXGIKAE-UHFFFAOYSA-N 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000003232 water-soluble binding agent Substances 0.000 description 1
- 239000002492 water-soluble polymer binding agent Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
- H01M50/434—Ceramics
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
- H01M50/434—Ceramics
- H01M50/437—Glass
-
- 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
- H01M50/491—Porosity
-
- 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 application relates to the field of battery materials, in particular, to a secondary battery, a battery diaphragm and a slurry for preparing a battery diaphragm coating.
- the separator is an important part of battery safety.
- the raw material of the lithium-ion battery separator is polyolefin.
- a single-sided or double-sided inorganic ceramic coating film is usually formed on the surface of the polyolefin, which can be improved to a certain extent.
- Polyolefin separator shrinks and deforms.
- this ceramic coating film is prone to curling and warping when it is dried and rolled, and the heat resistance of the separator is also an important factor to be considered in the improvement process.
- the present application provides a battery separator, which includes a base film and a coating covering the surface of the base film;
- the coating contains an adhesive, and the adhesive includes a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000, and the water-soluble polymer contains a first structural unit and a second structural unit ;
- the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the glass transition temperature of the homopolymer of the first monomer is more than or equal to 90 °C;
- the second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
- the weight average molecular weight of the water-soluble polymer is 240,000-570,000, such as 300,000-470,000, such as 360,000-410,000.
- the first monomer includes at least one of acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide, and styrene.
- the homopolymer of the first monomer has a glass transition temperature of 90°C to 150°C, for example, 93°C to 130°C, such as 96°C to 106°C.
- the polar group in the second monomer is an ester group or an amide.
- the second monomer includes N,N-methylenebisacrylamide and/or acrylate methacrylate.
- the ratio of the number of the first structural unit to the second structural unit is (85-95):(5-15), for example (87- 93):(7-13), such as (89-91):(9-11).
- the coating covers only one surface of the base film.
- the coating has a thickness of 2 ⁇ m ⁇ 4 ⁇ m, for example 2.5 ⁇ m ⁇ 3.5 ⁇ m, such as 3 ⁇ m.
- the coating also includes ceramic particles and a dispersant; the weight ratio of the ceramic particles, the binder and the dispersant is (90-96):(3-7):( 1 ⁇ 3), for example (90 ⁇ 92):(5 ⁇ 7):(1 ⁇ 3), such as (92 ⁇ 96):(3 ⁇ 4):(1 ⁇ 3);
- the ceramic particles include at least one of alumina, silica, titania, magnesia, zirconia and boehmite;
- the median particle diameter of the ceramic particles is 0.1 ⁇ m-1 ⁇ m, such as 0.3 ⁇ m-0.8 ⁇ m, such as 0.4 ⁇ m-0.6 ⁇ m, and the specific surface area is 2 m 2 /g-50 m 2 /g, such as 8 m 2 /g g ⁇ 45m 2 /g, such as between 19m 2 /g ⁇ 26m 2 /g;
- the dispersant includes at least one of ammonium polyacrylate, sodium polyacrylate and sodium hexametaphosphate.
- the material of the base film comprises polyethylene and/or polypropylene
- the porosity of the base film is 35%-60%, such as 40%-55%, such as 46%-49%;
- the thickness of the base film is 5 ⁇ m-25 ⁇ m, for example 9 ⁇ m-21 ⁇ m, such as 13 ⁇ m-18 ⁇ m.
- the present application also provides a secondary battery, which includes a positive pole piece, a negative pole piece, and the above-mentioned battery separator located between the positive pole piece and the negative pole piece.
- the battery separator is bonded to the positive electrode sheet and the negative electrode sheet by hot pressing.
- the present application also provides a slurry for preparing a battery separator coating, the slurry comprising ceramic particles, a binder, a dispersant and a solvent;
- the adhesive includes a water-soluble high molecular polymer, and the water-soluble high molecular polymer contains a first structural unit and a second structural unit;
- the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the glass transition temperature of the homopolymer of the first monomer is more than or equal to 90 °C;
- the second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
- the ceramic particles, the binder, and the dispersant in the slurry are each as defined above, which will not be repeated here.
- the solvent includes water and ethanol.
- the purpose of this application is to provide a secondary battery, a battery separator and a slurry for preparing a battery separator coating, which aims to improve the heat resistance of the battery separator, and at the same time improve the warping and curling of the battery separator coating.
- the reason why the coating of the battery separator is easy to curl is that the water-soluble binder used in the coating is a long-chain polymer, and the molecular chain changes from an extended state during the drying process of the coating. It is in the shape of a shrinking coil, which causes the stress state of the coated side and the non-coated side of the single-sided coated film to be different, resulting in curling of the single-sided coated film.
- the softness or rigidity of the molecular chain of the water-soluble adhesive is closely related to the degree of curling of the coating film.
- the softer the molecular chain of the adhesive the more serious the curling degree of the coating film; on the contrary, the stronger the rigidity of the molecular chain of the adhesive, the less likely the molecular chain is to shrink and curl, so the degree of curling deformation of the coating film is also small.
- the molecular chain flexibility of water-soluble adhesives is related to their glass transition temperature (Tg) and cross-linked structure. Polymer The glass transition temperature of a copolymer is related to the glass transition temperature of its monomer homopolymer.
- a suitable high molecular polymer is selected as a binder, and by controlling the rigidity and glass transition temperature of the polymer molecular chain, the purpose of improving or eliminating the curling and warping of the battery separator coating is achieved.
- the adhesive provided by the present application is also beneficial to improving the heat resistance of the battery separator, thereby improving the high temperature resistance of the coating.
- the application provides a battery separator, the battery separator includes a base film and a coating covering the surface of the base film;
- the coating contains an adhesive, and the adhesive includes a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000, and the water-soluble polymer contains a first structural unit and a second structural unit ;
- the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the glass transition temperature of the homopolymer of the first monomer is more than or equal to 90 °C;
- the second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
- the weight average molecular weight of the water-soluble polymer can be 200,000, 220,000, 240,000, 260,000, 270,000, 290,000, 300,000, 310,000, 350,000, 360,000, 390,000, 410,000, 440,000, 470,000, 530,000, 570,000, 600,000, etc.
- the weight-average molecular weight of the water-soluble polymer is 200,000 to 600,000, the molecular chain of the adhesive is more rigid, the molecular chain is not easy to shrink and curl, and the diaphragm is not easy to shrink after being heated, and the heat resistance is better.
- the first monomer includes at least one of acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide, and styrene.
- the first monomer can also be other monomers having a polar group and a carbon-carbon double bond functional group, and the glass of the homopolymer of the first monomer Transformation temperature ⁇ 90°C.
- the homopolymer of the first monomer can have a glass transition temperature of 90°C, 93°C, 96°C, 100°C, 106°C, 130°C, 150°C, and the like.
- the polar group in the second monomer is an ester group or an amide.
- the second monomer includes N,N-methylenebisacrylamide and/or acrylate methacrylate.
- the second monomer may also be other monomers having polar groups and at least two carbon-carbon double bond functional groups.
- the ratio of the number of units of the first structural unit to the second structural unit is (85-95):(5-15).
- the ratio of the number of units of the first structural unit to the second structural unit can be 85:15, 86:14, 87:13, 88:12, 89:11, 90:10, 91:10, 92:8, 93:7, 94:6, 95:5, etc.
- the coating can cover one surface of the base film, or alternatively, the coating can cover two opposite surfaces of the base film.
- the heat resistance of the coating is also better, and the shrinkage of the coating is small, which can reduce the force difference between the two surfaces of the base film, thereby avoiding shrinkage.
- the thickness of the coating is 2 ⁇ m ⁇ 4 ⁇ m, for example, the thickness of the coating can be 2 ⁇ m, 2.5 ⁇ m, 3 ⁇ m, 3.5 ⁇ m, 4 ⁇ m.
- the coating also includes ceramic particles and a dispersant.
- the weight ratio of ceramic particles, binder and dispersant is (90 ⁇ 96):(3 ⁇ 7):(1 ⁇ 3); for example, the weight ratio of ceramic particles, binder and dispersant is 90:3:1, 90:4:3, 90:5:2, 90:7:2, 92:3:3, 92:4:1, 92:7:3, 96:5:1, 96: 3:1, 96:7:1, 96:3:1, etc.
- the ceramic particles include at least one of alumina, silica, titania, magnesia, zirconia and boehmite.
- the median diameter of the ceramic particles is 0.1 ⁇ m to 1 ⁇ m, and the specific surface area is between 2 m 2 /g and 50 m 2 /g; for example, the median diameter of the ceramic particles can be 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m, 1 ⁇ m, etc.
- the specific surface area of ceramic particles can be 2m 2 /g, 5m 2 /g, 8m 2 /g, 11m 2 /g, 13m 2 /g, 17m 2 /g, 19m 2 /g, 21m 2 /g, 24m 2 /g, 26m 2 /g, 29m 2 /g, 34m 2 /g, 38m 2 /g, 41m 2 /g, 45m 2 /g, 47m 2 /g, 50m 2 /g and so on.
- the dispersant includes at least one of ammonium polyacrylate, sodium polyacrylate and sodium hexametaphosphate.
- the coating may also include other materials, such as incompletely volatilized solvents and the like.
- the material of the base film includes polyethylene and/or polypropylene.
- the present application is not limited to polyethylene, for example, it can be linear polyethylene, branched polyethylene; or, it can be high-density polyethylene with a density between 0.941 and 0.960 g/cubic centimeter, or a density between 0.915 and 0.940 g /cubic centimeter of low-density polyethylene.
- the material of the base film may also be a copolymer of polyethylene and polypropylene.
- the material of the base film may be other polymer materials.
- polytetrafluoroethylene polystyrene, and the like.
- the porosity of the base film is between 35% and 65%.
- the porosity of the base film is 35%, 36%, 40%, 42%, 46%, 47%, 49%, 52%, 55%, 58%, 60%, 63%, 65%, and so on.
- the base film has a thickness of 5 ⁇ m ⁇ 25 ⁇ m.
- the base film may have a thickness of 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 9 ⁇ m, 11 ⁇ m, 13 ⁇ m, 18 ⁇ m, 21 ⁇ m, 23 ⁇ m, 25 ⁇ m, or the like.
- the porosity of the base film and the thickness of the base film can be set according to the performance requirements of the battery separator, which are not limited in the embodiments of the present application.
- materials in the coating other than the binder can be selected according to their properties, for example, other materials can be selected for the dispersant and ceramic particles.
- the coating may contain other components besides the dispersant and ceramic particles.
- the water-soluble polymer composed of the first structural unit and the second structural unit has strong rigidity and a small shrinkage rate after heating; after it is used in the coating of the battery separator, it can improve the curling and warping of the battery separator; in addition, The heat resistance of the battery separator is effectively improved, and the thermal shrinkage rate of the battery separator is small.
- the coating on one side or both sides of the battery separator has better heat resistance.
- the present application also provides a secondary battery, which includes a positive electrode sheet, a negative electrode sheet, and the battery separator as described above.
- the battery separator is located between the positive pole piece and the negative pole piece, which can separate the positive pole piece and the negative pole piece.
- the battery separator is bonded to the positive electrode sheet and the negative electrode sheet by hot pressing.
- the secondary battery provided by the present application has better heat resistance and also improves the electrical performance of the secondary battery.
- the present application also provides a slurry for preparing a battery separator coating, which includes ceramic particles, a binder, a dispersant and a solvent.
- the adhesive is the adhesive as described above, and its detailed description can refer to the above.
- the ceramic particles and dispersant are the above-mentioned ceramic particles and dispersant, and their properties and parameters can be referred to above, and will not be repeated here.
- the solvent for preparing the slurry for the battery separator coating is water, and in other embodiments, it may also be other solvents, such as organic solvents such as ethanol.
- the slurry for preparing the battery diaphragm coating provided in the embodiment of the present application is coated on the base film, and can form a coating on the surface of the base film after curing.
- the coating obtained from the slurry has better heat resistance, and can improve or eliminate curling and warping of the coating.
- This embodiment provides a battery separator, which is mainly prepared through the following steps:
- the above-mentioned coating slurry is coated on one side surface of the polyethylene substrate by a gravure coating method, and dried.
- Embodiment 2-Example 4 respectively provide a battery separator, the preparation method of the battery separator can refer to Example 1, the difference is that the first monomer and the second monomer of the water-soluble high molecular polymer are not the same, for details, please refer to Table 1.
- Comparative Example 1-Comparative Example 4 respectively provide a battery separator.
- the preparation method of the battery separator refer to Example 1.
- the main difference is that the first monomer and the second monomer for preparing the water-soluble polymer are different.
- Example 1. See Table 1.
- Comparative Example 2 relates to the preparation of emulsion-type polymers, and its preparation method is different from that of Example 1.
- the method for preparing emulsion-type polymers is as follows:
- AA acrylic acid
- MAa acrylic acid
- AM methacrylic acid
- MMA acrylonitrile
- methyl methacrylate methacrylamide
- N N-Methylenebisacrylamide
- Acryl Methacrylate Methyl Acrylate.
- the values in Table 1 represent the molar ratios of the monomers in the total monomers of the examples or comparative examples.
- Thickness test Measured by Millimar film thickness gauge (Millimar C1208, German Marr company), test method see GB/T 6672-2001.
- Heat shrinkage test Refer to GB/T 12027-2004 for the test method, including: respectively measure the original length L0 of the sample along the direction of machine travel at room temperature, perpendicular to the direction of machine travel T0, place the sample in a constant temperature and humidity controllable oven, Heating at the test temperature according to the specified time and then cooling to the original test conditions, measure the length L1 of the sample along the direction of machine travel and the length T1 perpendicular to the direction of machine travel at this time, the calculation formula is as follows:
- Curl degree test take the coating sample to be tested with a width and length of 1m, and place it in the test area with a straight line of 1m (abbreviated as line a) and a straight line perpendicular to it engraved in the middle (abbreviated as line b). On the table, align the two ends of the sample with the two ends of the a-line. Place the steel ruler perpendicular to line b, and measure the distance between the edge of the sample near line a and the table top, in mm. When reading, one decimal place is an estimate. The larger the distance, the higher the curl degree of the coating film is, and the smaller the distance is, the smaller the curl degree of the coating film is. The test results are shown in Table 2.
- the battery separator of the present disclosure can improve the warping and warping of the battery separator coating by using a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000 consisting of the first structural unit and the second structural unit in the coating. It can be curled, and at the same time, the battery separator has good heat resistance and small thermal shrinkage rate, and the secondary battery made of it has good electrical performance, and has great application prospects in the field of battery materials.
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Abstract
The present application relates to the field of battery materials, and in particular, to a secondary battery, a battery separator, and a slurry for preparing a coating of the battery separator. The coating of the battery separator contains an adhesive; the adhesive comprises a water-soluble high-molecular polymer having a weight average molecular weight of 200,000 to 600,000; and the water-soluble high-molecular polymer contains a first structural unit and a second structural unit. The water-soluble high-molecular polymer constituted by the first structural unit and the second structural unit has strong rigidity, and has small shrinkage rate after heating; after the water-soluble high-molecular polymer is used in the coating of the battery separator, curling and wrapping of the battery separator can be improved; in addition, heat resistance of the battery separator is effectively improved, and the battery separator has a small heat shrinkage rate. Covering one surface or both surfaces of the battery separator with the coating provides good heat resistance.
Description
相关申请的交叉引用Cross References to Related Applications
本申请要求于2021年6月30日提交中国专利局的申请号为CN202110739430.5、名称为“二次电池、电池隔膜以及制备电池隔膜涂层的浆料”的中国专利申请的优先权,其全部内容通过引用结合在本公开中。This application claims the priority of the Chinese patent application with the application number CN202110739430.5 and titled "Secondary battery, battery separator and slurry for preparing battery separator coating" submitted to the China Patent Office on June 30, 2021. The entire contents are incorporated by reference in this disclosure.
本申请涉及电池材料领域,具体而言,涉及一种二次电池、电池隔膜以及制备电池隔膜涂层的浆料。The present application relates to the field of battery materials, in particular, to a secondary battery, a battery diaphragm and a slurry for preparing a battery diaphragm coating.
隔膜作为二次电池(例如锂电池)的重要组成部分之一,是电池安全性的重要组成部分。锂离子电池隔膜的原材料为聚烯烃,为了改善聚烯烃隔膜高温下收缩变形严重的问题,通常会在聚烯烃的表面上形成单面或双面无机陶瓷涂布膜,这在一定程度上可以改善聚烯烃隔膜收缩变形。但是,这种陶瓷涂布膜干燥收卷时很容易发生卷曲和翘边,并且隔膜的耐热性也是改善过程中需要考虑的重要因素。As one of the important components of secondary batteries (such as lithium batteries), the separator is an important part of battery safety. The raw material of the lithium-ion battery separator is polyolefin. In order to improve the problem of severe shrinkage and deformation of the polyolefin separator at high temperature, a single-sided or double-sided inorganic ceramic coating film is usually formed on the surface of the polyolefin, which can be improved to a certain extent. Polyolefin separator shrinks and deforms. However, this ceramic coating film is prone to curling and warping when it is dried and rolled, and the heat resistance of the separator is also an important factor to be considered in the improvement process.
发明内容Contents of the invention
本申请提供了一种电池隔膜,所述电池隔膜包括基膜和覆盖所述基膜的表面的涂层;The present application provides a battery separator, which includes a base film and a coating covering the surface of the base film;
所述涂层含有粘合剂,所述粘合剂包括重均分子量为20万~60万的水溶性高分子聚合物,所述水溶性高分子聚合物含有第一结构单元和第二结构单元;The coating contains an adhesive, and the adhesive includes a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000, and the water-soluble polymer contains a first structural unit and a second structural unit ;
其中,形成所述第一结构单元的第一单体为具有一个极性基团和一个碳碳双键官能团的单体,且所述第一单体的均聚物的玻璃化转变温度≥90℃;Wherein, the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the glass transition temperature of the homopolymer of the first monomer is more than or equal to 90 ℃;
形成所述第二结构单元的第二单体为具有极性基团和至少两个碳碳双键官能团的单体。The second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
可选地,所述水溶性高分子聚合物的重均分子量为24万~57万,例如30万~47万,诸如36万~41万。Optionally, the weight average molecular weight of the water-soluble polymer is 240,000-570,000, such as 300,000-470,000, such as 360,000-410,000.
在一些实施方式中,所述第一单体包括丙烯酸、甲基丙烯酸、丙烯酰胺、丙烯腈、甲基丙烯酸甲酯、甲基丙烯酰胺以及苯乙烯中的至少一种。In some embodiments, the first monomer includes at least one of acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide, and styrene.
可选地,所述第一单体的均聚物的玻璃化转变温度为90℃~150℃,例如93℃~130℃, 诸如96℃~106℃。Optionally, the homopolymer of the first monomer has a glass transition temperature of 90°C to 150°C, for example, 93°C to 130°C, such as 96°C to 106°C.
在一些实施方式中,所述第二单体中所述极性基团为酯基或酰胺。In some embodiments, the polar group in the second monomer is an ester group or an amide.
可选地,所述第二单体包括N,N-亚甲基双丙烯酰胺和/或甲基丙烯酸丙烯酯。Optionally, the second monomer includes N,N-methylenebisacrylamide and/or acrylate methacrylate.
在一些实施方式中,所述水溶性高分子聚合物中:所述第一结构单元和所述第二结构单元的数量之比为(85-95):(5-15),例如(87-93):(7-13),诸如(89-91):(9-11)。In some embodiments, in the water-soluble polymer: the ratio of the number of the first structural unit to the second structural unit is (85-95):(5-15), for example (87- 93):(7-13), such as (89-91):(9-11).
在一些实施方式中,所述涂层仅覆盖所述基膜的一个表面。In some embodiments, the coating covers only one surface of the base film.
可选地,所述涂层的厚度为2μm~4μm,例如2.5μm~3.5μm,诸如3μm。Optionally, the coating has a thickness of 2 μm˜4 μm, for example 2.5 μm˜3.5 μm, such as 3 μm.
在一些实施方式中,所述涂层还包括陶瓷颗粒和分散剂;所述陶瓷颗粒、所述粘合剂以及所述分散剂的重量比为(90~96):(3~7):(1~3),例如(90~92):(5~7):(1~3),诸如(92~96):(3~4):(1~3);In some embodiments, the coating also includes ceramic particles and a dispersant; the weight ratio of the ceramic particles, the binder and the dispersant is (90-96):(3-7):( 1~3), for example (90~92):(5~7):(1~3), such as (92~96):(3~4):(1~3);
可选地,所述陶瓷颗粒包括氧化铝、氧化硅、氧化钛、氧化镁、氧化锆及勃姆石中的至少一种;Optionally, the ceramic particles include at least one of alumina, silica, titania, magnesia, zirconia and boehmite;
可选地,所述陶瓷颗粒的中位粒径为0.1μm~1μm,例如0.3μm~0.8μm,诸如0.4μm~0.6μm,比表面积为2m
2/g~50m
2/g,例如8m
2/g~45m
2/g,诸如19m
2/g~26m
2/g之间;
Optionally, the median particle diameter of the ceramic particles is 0.1 μm-1 μm, such as 0.3 μm-0.8 μm, such as 0.4 μm-0.6 μm, and the specific surface area is 2 m 2 /g-50 m 2 /g, such as 8 m 2 /g g~45m 2 /g, such as between 19m 2 /g~26m 2 /g;
可选地,所述分散剂包括聚丙烯酸铵、聚丙烯酸钠及六偏磷酸钠中的至少一种。Optionally, the dispersant includes at least one of ammonium polyacrylate, sodium polyacrylate and sodium hexametaphosphate.
在一些实施方式中,所述基膜的材料包括聚乙烯和/或聚丙烯;In some embodiments, the material of the base film comprises polyethylene and/or polypropylene;
可选地,所述基膜的孔隙率为35%~60%,例如40%~55%,诸如46%~49%;Optionally, the porosity of the base film is 35%-60%, such as 40%-55%, such as 46%-49%;
可选地,所述基膜的厚度为5μm~25μm,例如9μm~21μm,诸如13μm~18μm。Optionally, the thickness of the base film is 5 μm-25 μm, for example 9 μm-21 μm, such as 13 μm-18 μm.
本申请还提供了一种二次电池,所述二次电池包括正极极片、负极极片以及位于所述正极极片和所述负极极片之间的根据上文所述的电池隔膜。The present application also provides a secondary battery, which includes a positive pole piece, a negative pole piece, and the above-mentioned battery separator located between the positive pole piece and the negative pole piece.
在一些实施方式中,所述电池隔膜与所述正极极片、所述负极极片通过热压贴合。In some embodiments, the battery separator is bonded to the positive electrode sheet and the negative electrode sheet by hot pressing.
本申请还提供了一种制备电池隔膜涂层的浆料,所述浆料包括陶瓷颗粒、粘合剂、分散剂及溶剂;The present application also provides a slurry for preparing a battery separator coating, the slurry comprising ceramic particles, a binder, a dispersant and a solvent;
所述粘合剂包括水溶性高分子聚合物,所述水溶性高分子聚合物含有第一结构单元和第二结构单元;The adhesive includes a water-soluble high molecular polymer, and the water-soluble high molecular polymer contains a first structural unit and a second structural unit;
其中,形成所述第一结构单元的第一单体为具有一个极性基团和一个碳碳双键官能团的单体,且所述第一单体的均聚物的玻璃化转变温度≥90℃;Wherein, the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the glass transition temperature of the homopolymer of the first monomer is more than or equal to 90 ℃;
形成所述第二结构单元的第二单体为具有极性基团和至少两个碳碳双键官能团的单体。The second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
在一些实施方式中,所述浆料中的所述陶瓷颗粒、所述粘合剂以及所述分散剂各自如上文所限定的,在此不再赘述。In some embodiments, the ceramic particles, the binder, and the dispersant in the slurry are each as defined above, which will not be repeated here.
可选地,所述溶剂包括水和乙醇。Optionally, the solvent includes water and ethanol.
为使本申请的目的、技术方案和优点更加清楚,下面将对本申请的实施方案进行详细描述。实施例中未注明具体条件者,按照常规条件或制造商建议的条件进行。所用试剂或仪器未注明生产厂商者,均为可以通过市售购买获得的常规产品。In order to make the purpose, technical solutions and advantages of the present application clearer, the implementation of the present application will be described in detail below. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.
本申请的目的在于提供一种二次电池、电池隔膜以及制备电池隔膜涂层的浆料,其旨在改善电池隔膜的耐热性,同时还改善电池隔膜涂层的翘边和卷曲。The purpose of this application is to provide a secondary battery, a battery separator and a slurry for preparing a battery separator coating, which aims to improve the heat resistance of the battery separator, and at the same time improve the warping and curling of the battery separator coating.
发明人在研究过程中发现:电池隔膜的涂层容易卷曲的原因在于,涂层中使用的水溶性粘合剂为长链高分子聚合物,在涂层干燥过程中,分子链由伸展状态转变为收缩的线团状,这就导致了单面涂布膜的涂布面和非涂布面受力状态不同,从而导致单面涂布膜发生卷曲。The inventor found during the research process that the reason why the coating of the battery separator is easy to curl is that the water-soluble binder used in the coating is a long-chain polymer, and the molecular chain changes from an extended state during the drying process of the coating. It is in the shape of a shrinking coil, which causes the stress state of the coated side and the non-coated side of the single-sided coated film to be different, resulting in curling of the single-sided coated film.
其中,水溶性粘合剂的分子链柔软性或刚性与涂布膜的卷曲程度息息相关。粘合剂分子链越柔软,涂布膜卷曲程度越严重;反之,粘合剂分子链刚性越强,分子链越不易收缩卷曲,因此涂布膜卷曲变形程度也小。而水溶性粘合剂的分子链柔软性与其玻璃化转变温度(Tg)和交联结构有关。聚合物共聚物的玻璃化转变温度与其单体均聚物的玻璃化转变温度相关。Among them, the softness or rigidity of the molecular chain of the water-soluble adhesive is closely related to the degree of curling of the coating film. The softer the molecular chain of the adhesive, the more serious the curling degree of the coating film; on the contrary, the stronger the rigidity of the molecular chain of the adhesive, the less likely the molecular chain is to shrink and curl, so the degree of curling deformation of the coating film is also small. The molecular chain flexibility of water-soluble adhesives is related to their glass transition temperature (Tg) and cross-linked structure. Polymer The glass transition temperature of a copolymer is related to the glass transition temperature of its monomer homopolymer.
在本申请中,选择合适高分子聚合物作为粘合剂,通过控制聚合物分子链的刚性以及玻璃化转变温度,从而达到改善或消除电池隔膜涂层卷曲和翘边的目的。此外,本申请提供的粘合剂也有利于提高电池隔膜的耐热性,从而提升涂层的耐高温性能。In this application, a suitable high molecular polymer is selected as a binder, and by controlling the rigidity and glass transition temperature of the polymer molecular chain, the purpose of improving or eliminating the curling and warping of the battery separator coating is achieved. In addition, the adhesive provided by the present application is also beneficial to improving the heat resistance of the battery separator, thereby improving the high temperature resistance of the coating.
本申请提供了一种电池隔膜,电池隔膜包括基膜和覆盖基膜表面的涂层;The application provides a battery separator, the battery separator includes a base film and a coating covering the surface of the base film;
所述涂层含有粘合剂,所述粘合剂包括重均分子量为20万~60万的水溶性高分子聚合物,所述水溶性高分子聚合物含有第一结构单元和第二结构单元;The coating contains an adhesive, and the adhesive includes a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000, and the water-soluble polymer contains a first structural unit and a second structural unit ;
其中,形成所述第一结构单元的第一单体为具有一个极性基团和一个碳碳双键官能团的单体,且所述第一单体的均聚物的玻璃化转变温度≥90℃;Wherein, the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the glass transition temperature of the homopolymer of the first monomer is more than or equal to 90 ℃;
形成所述第二结构单元的第二单体为具有极性基团和至少两个碳碳双键官能团的单体。The second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
作为示例性地,水溶性高分子聚合物的重均分子量可以为20万、22万、24万、26万、27万、29万、30万、31万、35万、36万、39万、41万、44万、47万、53万、57万、60万等等。当水溶性高分子聚合物的重均分子量为20万~60万时,粘合剂分子链刚性较强,分子链不易收缩卷曲,隔膜受热之后不易收缩,耐热性更优。As an example, the weight average molecular weight of the water-soluble polymer can be 200,000, 220,000, 240,000, 260,000, 270,000, 290,000, 300,000, 310,000, 350,000, 360,000, 390,000, 410,000, 440,000, 470,000, 530,000, 570,000, 600,000, etc. When the weight-average molecular weight of the water-soluble polymer is 200,000 to 600,000, the molecular chain of the adhesive is more rigid, the molecular chain is not easy to shrink and curl, and the diaphragm is not easy to shrink after being heated, and the heat resistance is better.
在一些实施方式中,第一单体包括丙烯酸、甲基丙烯酸、丙烯酰胺、丙烯腈、甲基丙烯酸甲酯、甲基丙烯酰胺以及苯乙烯中的至少一种。In some embodiments, the first monomer includes at least one of acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide, and styrene.
需要说明的是,在本申请的其他实施方式中,第一单体也可以为其他具有一个极性基团和一个碳碳双键官能团的单体,且第一单体的均聚物的玻璃化转变温度≥90℃。例如,第一单体的均聚物的玻璃化转变温度可以为90℃、93℃、96℃、100℃、106℃、130℃、150℃等等。It should be noted that, in other embodiments of the present application, the first monomer can also be other monomers having a polar group and a carbon-carbon double bond functional group, and the glass of the homopolymer of the first monomer Transformation temperature ≥ 90°C. For example, the homopolymer of the first monomer can have a glass transition temperature of 90°C, 93°C, 96°C, 100°C, 106°C, 130°C, 150°C, and the like.
在一些实施方式中,第二单体中的极性基团为酯基或酰胺。作为示例性地,第二单体包括N,N-亚甲基双丙烯酰胺和/或甲基丙烯酸丙烯酯。In some embodiments, the polar group in the second monomer is an ester group or an amide. Exemplarily, the second monomer includes N,N-methylenebisacrylamide and/or acrylate methacrylate.
需要说明的是,在本申请的其他实施方式中,第二单体也可以为其他具有极性基团和至少两个碳碳双键官能团的单体。It should be noted that, in other embodiments of the present application, the second monomer may also be other monomers having polar groups and at least two carbon-carbon double bond functional groups.
在一些实施方式中,水溶性高分子聚合物中:第一结构单元和第二结构单元的单元数之比为(85-95):(5-15)。例如,第一结构单元和第二结构单元的单元数之比可以为85:15、86:14、87:13、88:12、89:11、90:10、91:10、92:8、93:7、94:6、95:5等等。In some embodiments, in the water-soluble polymer: the ratio of the number of units of the first structural unit to the second structural unit is (85-95):(5-15). For example, the ratio of the number of units of the first structural unit to the second structural unit can be 85:15, 86:14, 87:13, 88:12, 89:11, 90:10, 91:10, 92:8, 93:7, 94:6, 95:5, etc.
在一些实施方式中,涂层可以覆盖基膜的一个表面,或者,涂层也可以覆盖基膜相对的两个表面。对于涂层覆盖基膜一个表面的实施方式而言,涂层的耐热性也较佳,涂层的收缩量较小,可减小基膜两个表面的受力差,从而避免收缩。In some embodiments, the coating can cover one surface of the base film, or alternatively, the coating can cover two opposite surfaces of the base film. For the embodiment in which the coating covers one surface of the base film, the heat resistance of the coating is also better, and the shrinkage of the coating is small, which can reduce the force difference between the two surfaces of the base film, thereby avoiding shrinkage.
在一些实施方式中,涂层的厚度为2μm~4μm,例如涂层的厚度可以为2μm、2.5μm、3μm、3.5μm、4μm。In some embodiments, the thickness of the coating is 2 μm˜4 μm, for example, the thickness of the coating can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm.
在一些实施方式中,涂层还包括陶瓷颗粒和分散剂。可选地,陶瓷颗粒、粘合剂以及分散剂的重量比为(90~96):(3~7):(1~3);例如,陶瓷颗粒、粘合剂以及分散剂的重量比为90:3:1、90:4:3、90:5:2、90:7:2、92:3:3、92:4:1、92:7:3、96:5:1、96:3:1、96:7:1、96:3:1等等。In some embodiments, the coating also includes ceramic particles and a dispersant. Optionally, the weight ratio of ceramic particles, binder and dispersant is (90~96):(3~7):(1~3); for example, the weight ratio of ceramic particles, binder and dispersant is 90:3:1, 90:4:3, 90:5:2, 90:7:2, 92:3:3, 92:4:1, 92:7:3, 96:5:1, 96: 3:1, 96:7:1, 96:3:1, etc.
可选地,陶瓷颗粒包括氧化铝、氧化硅、氧化钛、氧化镁、氧化锆及勃姆石中的至少一种。Optionally, the ceramic particles include at least one of alumina, silica, titania, magnesia, zirconia and boehmite.
可选地,陶瓷颗粒的中位粒径为0.1μm~1μm,比表面积为2m
2/g~50m
2/g之间;例如,陶瓷颗粒的中位粒径可以为0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm、1μm等等。例如,陶瓷颗粒的比表面积可以为2m
2/g、5m
2/g、8m
2/g、11m
2/g、13m
2/g、17m
2/g、19m
2/g、21m
2/g、24m
2/g、26m
2/g、29m
2/g、34m
2/g、38m
2/g、41m
2/g、45m
2/g、47m
2/g、50m
2/g等等。
Optionally, the median diameter of the ceramic particles is 0.1 μm to 1 μm, and the specific surface area is between 2 m 2 /g and 50 m 2 /g; for example, the median diameter of the ceramic particles can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, etc. For example, the specific surface area of ceramic particles can be 2m 2 /g, 5m 2 /g, 8m 2 /g, 11m 2 /g, 13m 2 /g, 17m 2 /g, 19m 2 /g, 21m 2 /g, 24m 2 /g, 26m 2 /g, 29m 2 /g, 34m 2 /g, 38m 2 /g, 41m 2 /g, 45m 2 /g, 47m 2 /g, 50m 2 /g and so on.
可选地,分散剂包括聚丙烯酸铵、聚丙烯酸钠及六偏磷酸钠中的至少一种。Optionally, the dispersant includes at least one of ammonium polyacrylate, sodium polyacrylate and sodium hexametaphosphate.
在本申请的其他实施方式中,涂层也还可以包括其他材料,例如未完全挥发的溶剂等等。In other embodiments of the present application, the coating may also include other materials, such as incompletely volatilized solvents and the like.
在一些实施方式中,基膜的材料包括聚乙烯和/或聚丙烯。本申请不对聚乙烯进行限制,例如可以为线性聚乙烯、支化聚乙烯;或者,可以是密度介于0.941~0.960克/立方厘米之间的高密度聚乙烯、或密度介于0.915~0.940克/立方厘米之间的低密度聚乙烯。基膜的材 料也可以是聚乙烯和聚丙烯的共聚物。In some embodiments, the material of the base film includes polyethylene and/or polypropylene. The present application is not limited to polyethylene, for example, it can be linear polyethylene, branched polyethylene; or, it can be high-density polyethylene with a density between 0.941 and 0.960 g/cubic centimeter, or a density between 0.915 and 0.940 g /cubic centimeter of low-density polyethylene. The material of the base film may also be a copolymer of polyethylene and polypropylene.
在本申请的其他实施方式中,基膜的材料可以为其他高分子材料。例如,聚四氟乙烯、聚苯乙烯等等。In other embodiments of the present application, the material of the base film may be other polymer materials. For example, polytetrafluoroethylene, polystyrene, and the like.
可选地,基膜的孔隙率介于35%~65%之间。例如,基膜的孔隙率为35%、36%、40%、42%、46%、47%、49%、52%、55%、58%、60%、63%、65%等等。Optionally, the porosity of the base film is between 35% and 65%. For example, the porosity of the base film is 35%, 36%, 40%, 42%, 46%, 47%, 49%, 52%, 55%, 58%, 60%, 63%, 65%, and so on.
可选地,基膜的厚度为5μm~25μm。例如,基膜的厚度可以为5μm、6μm、7μm、9μm、11μm、13μm、18μm、21μm、23μm、25μm等等。Optionally, the base film has a thickness of 5 μm˜25 μm. For example, the base film may have a thickness of 5 μm, 6 μm, 7 μm, 9 μm, 11 μm, 13 μm, 18 μm, 21 μm, 23 μm, 25 μm, or the like.
需要说明的是,在本申请的其他实施方式中,基膜的空隙率以及基膜的厚度可以根据电池隔膜的性能需求进行设置,本申请的实施方式不对其进行限制。It should be noted that, in other embodiments of the present application, the porosity of the base film and the thickness of the base film can be set according to the performance requirements of the battery separator, which are not limited in the embodiments of the present application.
还需要说明的是,在本申请的其他实施方式中,涂层中除了粘合剂之外的材料可以根据其性能进行选择,例如分散剂、陶瓷颗粒可以选用其他材料。相应地,涂层中除了分散剂、陶瓷颗粒之外可以还含有其他成分。It should also be noted that in other embodiments of the present application, materials in the coating other than the binder can be selected according to their properties, for example, other materials can be selected for the dispersant and ceramic particles. Correspondingly, the coating may contain other components besides the dispersant and ceramic particles.
本申请实施方式提供的电池隔膜至少具有以下优点:The battery separator provided by the embodiments of the present application has at least the following advantages:
由第一结构单元、第二结构单元构成的水溶性高分子聚合物刚性较强,加热后收缩率较小;其用于电池隔膜的涂层后,可以改善电池隔膜卷曲和翘边;此外,该电池隔膜的耐热性能得到了有效改善,电池隔膜的热收缩率较小。该电池隔膜一面覆盖涂层或者两面覆盖涂层均具有较佳的耐热性能。The water-soluble polymer composed of the first structural unit and the second structural unit has strong rigidity and a small shrinkage rate after heating; after it is used in the coating of the battery separator, it can improve the curling and warping of the battery separator; in addition, The heat resistance of the battery separator is effectively improved, and the thermal shrinkage rate of the battery separator is small. The coating on one side or both sides of the battery separator has better heat resistance.
本申请还提供了一种二次电池,二次电池包括正极极片、负极极片以及如上文所述的电池隔膜。电池隔膜位于正极极片和负极极片之间,可以分隔正极极片和负极极片。The present application also provides a secondary battery, which includes a positive electrode sheet, a negative electrode sheet, and the battery separator as described above. The battery separator is located between the positive pole piece and the negative pole piece, which can separate the positive pole piece and the negative pole piece.
在一些实施方式中,电池隔膜与正极极片、负极极片通过热压贴合。In some embodiments, the battery separator is bonded to the positive electrode sheet and the negative electrode sheet by hot pressing.
基于电池隔膜的上述优点,本申请提供的二次电池的耐热性较好,也提高了二次电池的电性能。Based on the above advantages of the battery separator, the secondary battery provided by the present application has better heat resistance and also improves the electrical performance of the secondary battery.
本申请还提供了一种制备电池隔膜涂层的浆料,制备电池隔膜涂层的浆料包括陶瓷颗粒、粘合剂、分散剂及溶剂。其中,粘合剂是如上文所述的粘合剂,其详细描述可参阅上文。The present application also provides a slurry for preparing a battery separator coating, which includes ceramic particles, a binder, a dispersant and a solvent. Wherein, the adhesive is the adhesive as described above, and its detailed description can refer to the above.
在一些实施方式中,陶瓷颗粒和分散剂为如上文所述的陶瓷颗粒和分散剂,其性能以及参数可参阅上文,此处不再赘述。In some embodiments, the ceramic particles and dispersant are the above-mentioned ceramic particles and dispersant, and their properties and parameters can be referred to above, and will not be repeated here.
在一些实施方式中,制备电池隔膜涂层的浆料的溶剂为水,在其他实施方式中,也可以为其他溶剂,例如乙醇等有机溶剂。In some embodiments, the solvent for preparing the slurry for the battery separator coating is water, and in other embodiments, it may also be other solvents, such as organic solvents such as ethanol.
本申请实施方式提供的制备电池隔膜涂层的浆料涂覆于基膜,固化后能在基膜表面形成涂层。该浆料得到的涂层具有较佳的耐热性,同时能够改善或消除涂层的卷曲和翘边。The slurry for preparing the battery diaphragm coating provided in the embodiment of the present application is coated on the base film, and can form a coating on the surface of the base film after curing. The coating obtained from the slurry has better heat resistance, and can improve or eliminate curling and warping of the coating.
以下结合实施例对本申请的特征和性能作进一步的详细描述。The characteristics and performance of the present application will be described in further detail below in conjunction with the examples.
实施例1Example 1
本实施例提供了一种电池隔膜,主要通过以下步骤制得:This embodiment provides a battery separator, which is mainly prepared through the following steps:
制备水溶性高分子聚合物:Preparation of water-soluble polymers:
在装有搅拌器、温度计和回流冷凝管的四口烧瓶中加入一定量的正丁醇、乙醇,升温至140℃,然后将甲基丙烯酸、丙烯酰胺以及甲基丙烯酸丙烯酯单体摩尔质量比为80:10:10的混合物、引发剂在4小时内滴加至完毕,保温2小时,补加引发剂,保温2小时,中和pH值至4~6,加水过滤出料,即制得水溶性高分子聚合物粘合剂。Add a certain amount of n-butanol and ethanol into a four-necked flask equipped with a stirrer, a thermometer and a reflux condenser, raise the temperature to 140°C, and then mix the molar mass ratio of methacrylic acid, acrylamide and propylene methacrylate monomer It is a mixture of 80:10:10, the initiator is added dropwise within 4 hours, and the temperature is kept for 2 hours, and the initiator is added, and the temperature is kept for 2 hours, and the pH value is neutralized to 4-6, and the water is added to filter the material, and the product is obtained Water-soluble polymer binder.
制备电池隔膜涂层的浆料:Preparation of slurry for battery separator coating:
将分散剂(聚丙烯酸铵)加入水中,混和均匀得分散剂溶液;在分散剂溶液中加入陶瓷颗粒(氧化铝),球磨分散得到浆液,加入水溶性高分子聚合物作为粘合剂,混合后得到涂层浆料;其中,以陶瓷颗粒、粘合剂及分散剂的总重量为100份计,陶瓷颗粒的重量份为90份,粘合剂的重量份为5份。Add the dispersant (ammonium polyacrylate) into the water and mix evenly to obtain the dispersant solution; add ceramic particles (alumina) to the dispersant solution, disperse by ball milling to obtain a slurry, add a water-soluble high molecular polymer as a binder, and mix to obtain Coating slurry; wherein, based on 100 parts of the total weight of the ceramic particles, binder and dispersant, the weight part of the ceramic particle is 90 parts, and the weight part of the binder is 5 parts.
使用凹版涂布的方法将上述涂层浆料涂布在聚乙烯基材的一侧表面,烘干。The above-mentioned coating slurry is coated on one side surface of the polyethylene substrate by a gravure coating method, and dried.
实施例2-实施例4Example 2-Example 4
实施例2-实施例4分别提供一种电池隔膜,该电池隔膜的制备方法参阅实施例1,区别在于制备水溶性高分子聚合物的第一单体和第二单体不相同,具体请参见表1。Embodiment 2-Example 4 respectively provide a battery separator, the preparation method of the battery separator can refer to Example 1, the difference is that the first monomer and the second monomer of the water-soluble high molecular polymer are not the same, for details, please refer to Table 1.
对比例1-对比例4Comparative Example 1-Comparative Example 4
对比例1-对比例4分别提供一种电池隔膜,该电池隔膜的制备方法参阅实施例1,主要区别在于制备水溶性高分子聚合物的第一单体和第二单体不相同,具体请参见表1。Comparative Example 1-Comparative Example 4 respectively provide a battery separator. For the preparation method of the battery separator, refer to Example 1. The main difference is that the first monomer and the second monomer for preparing the water-soluble polymer are different. For details, please refer to Example 1. See Table 1.
另外,对比例2涉及制备乳液型高分子聚合物,其制备方法与实施例1的方法不同,在对比例2中,制备乳液型高分子聚合物的方法如下:In addition, Comparative Example 2 relates to the preparation of emulsion-type polymers, and its preparation method is different from that of Example 1. In Comparative Example 2, the method for preparing emulsion-type polymers is as follows:
在装有搅拌器、温度计和回流冷凝管的四口烧瓶中加入一定量的去离子水、乳化剂和5wt%第一单体和第二单体的(第一单体和第二单体之和为5wt%)共混单体,搅拌30分钟,升温至80℃,然后再将其余95%的第一单体和第二单体的混合物在3小时内滴加完毕,然后降温至50℃;补加氨水调节pH值至7-8之间,过滤出料,制得乳液型高分子聚合物粘合剂。Add a certain amount of deionized water, emulsifier and 5wt% of the first monomer and the second monomer (between the first monomer and the second monomer) in the four-necked flask equipped with stirrer, thermometer and reflux condenser and 5wt%) blended monomers, stirred for 30 minutes, heated up to 80°C, then added the remaining 95% of the mixture of the first monomer and the second monomer dropwise within 3 hours, and then cooled down to 50°C Adding ammonia water to adjust the pH value to 7-8, filtering and discharging the material to obtain an emulsion-type high molecular polymer adhesive.
表1Table 1
表1中,缩写AA、MAa、AM、AN、MMA、MAM、MBA、AMA、MA分别指的是丙烯酸、甲基丙烯酸、丙烯酰胺、丙烯腈、甲基丙烯酸甲酯、甲基丙烯酰胺、N,N-亚甲基双丙烯酰胺、甲基丙烯酸丙烯酯、丙烯酸甲酯。表1中的数值代表该单体在其实施例或对比例总单体中的所占摩尔比。In Table 1, the abbreviations AA, MAa, AM, AN, MMA, MAM, MBA, AMA, MA refer to acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide, N , N-Methylenebisacrylamide, Acryl Methacrylate, Methyl Acrylate. The values in Table 1 represent the molar ratios of the monomers in the total monomers of the examples or comparative examples.
试验例Test case
测试实施例1-4、对比例1-4提供的隔膜的性能。The properties of the separators provided in Examples 1-4 and Comparative Examples 1-4 were tested.
具体测试方法介绍如下:The specific test method is introduced as follows:
厚度测试:采用马尔薄膜测厚仪(Millimar C1208,德国马尔公司)测定,测试方法参见GB/T 6672-2001。Thickness test: Measured by Millimar film thickness gauge (Millimar C1208, German Marr company), test method see GB/T 6672-2001.
热收缩测试:测试方法参见GB/T 12027-2004,包括:在室温下分别测定试样沿机器行进方向原始长度L0,垂直于机器行进方向T0,将试样在恒温恒湿可控烘箱中,按照规定时间以试验温度加热后冷却至原始测试条件下,测定此时试样沿机器行进方向长度L1和垂直机器行进方向长度T1,计算公式如下:Heat shrinkage test: Refer to GB/T 12027-2004 for the test method, including: respectively measure the original length L0 of the sample along the direction of machine travel at room temperature, perpendicular to the direction of machine travel T0, place the sample in a constant temperature and humidity controllable oven, Heating at the test temperature according to the specified time and then cooling to the original test conditions, measure the length L1 of the sample along the direction of machine travel and the length T1 perpendicular to the direction of machine travel at this time, the calculation formula is as follows:
MD%=(L1-L0)/L0×100%MD%=(L1-L0)/L0×100%
TD%=(T1-T0)/T0×100%TD%=(T1-T0)/T0×100%
卷曲度测试:取幅宽及长度均为1m的待测涂布样品,将其放在刻有一条1m直线(简称a线)及中间刻有一条与之垂直的直线(简称b线)的试验台面上,将样品两端对齐a线的两端。将钢直尺与b线垂直放置,测量靠近a线的样品边缘与台面的距离,单位为mm。读数时,小数点后面一位为估计值。距离越大,说明该涂布膜的卷曲度越高,距离越小则该涂布膜的卷曲度小。测试结果如表2所示。Curl degree test: take the coating sample to be tested with a width and length of 1m, and place it in the test area with a straight line of 1m (abbreviated as line a) and a straight line perpendicular to it engraved in the middle (abbreviated as line b). On the table, align the two ends of the sample with the two ends of the a-line. Place the steel ruler perpendicular to line b, and measure the distance between the edge of the sample near line a and the table top, in mm. When reading, one decimal place is an estimate. The larger the distance, the higher the curl degree of the coating film is, and the smaller the distance is, the smaller the curl degree of the coating film is. The test results are shown in Table 2.
表2Table 2
从表1和表2可以看出,在相同厚度条件下,本申请实施例1-实施例4提供的隔膜具有较低的热收缩率,说明其耐热性能较佳。另外,隔膜的卷曲也得到有效改善。It can be seen from Table 1 and Table 2 that, under the same thickness conditions, the separators provided in Examples 1-4 of the present application have lower thermal shrinkage rates, indicating that they have better heat resistance. In addition, curling of the separator is also effectively improved.
以上所述仅为本申请的优选实施例而已,并不用于限制本申请,对于本领域的技术人员来说,本申请可以有各种更改和变化。凡在本申请的精神和原则之内,所作的任何修改、等同替换、改进等,均应包含在本申请的保护范围之内。The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.
本公开的电池隔膜通过在涂层中使用由第一结构单元、第二结构单元构成的重均分子量为20万~60万的水溶性高分子聚合物,能够改善电池隔膜涂层的翘边和卷曲,同时使电池隔膜具有较好的耐热性能和较小的热收缩率,由其制成的二次电池电性能良好,在电池材料领域具有极大的应用前景。The battery separator of the present disclosure can improve the warping and warping of the battery separator coating by using a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000 consisting of the first structural unit and the second structural unit in the coating. It can be curled, and at the same time, the battery separator has good heat resistance and small thermal shrinkage rate, and the secondary battery made of it has good electrical performance, and has great application prospects in the field of battery materials.
Claims (19)
- 一种电池隔膜,其特征在于,所述电池隔膜包括基膜和覆盖所述基膜的表面的涂层;A battery separator, characterized in that the battery separator includes a base film and a coating covering the surface of the base film;所述涂层含有粘合剂,所述粘合剂包括重均分子量为20万~60万的水溶性高分子聚合物,所述水溶性高分子聚合物含有第一结构单元和第二结构单元;The coating contains an adhesive, and the adhesive includes a water-soluble polymer with a weight average molecular weight of 200,000 to 600,000, and the water-soluble polymer contains a first structural unit and a second structural unit ;其中,形成所述第一结构单元的第一单体为具有一个极性基团和一个碳碳双键官能团的单体,且所述第一单体的均聚物的玻璃化转变温度≥90℃;Wherein, the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the homopolymer of the first monomer has a glass transition temperature ≥ 90 ℃;形成所述第二结构单元的第二单体为具有极性基团和至少两个碳碳双键官能团的单体。The second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
- 根据权利要求1所述的电池隔膜,其特征在于,所述水溶性高分子聚合物的重均分子量为24万~57万,例如30万~47万,诸如36万~41万。The battery separator according to claim 1, wherein the water-soluble polymer has a weight average molecular weight of 240,000-570,000, such as 300,000-470,000, such as 360,000-410,000.
- 根据权利要求1或2所述的电池隔膜,其特征在于,所述第一单体包括丙烯酸、甲基丙烯酸、丙烯酰胺、丙烯腈、甲基丙烯酸甲酯、甲基丙烯酰胺以及苯乙烯中的至少一种。The battery separator according to claim 1 or 2, wherein the first monomer comprises acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide and styrene at least one.
- 根据权利要求1-3任一项所述的电池隔膜,其特征在于,所述第一单体的均聚物的玻璃化转变温度为90℃~150℃,例如93℃~130℃,诸如96℃~106℃。The battery separator according to any one of claims 1-3, wherein the glass transition temperature of the homopolymer of the first monomer is 90°C to 150°C, for example 93°C to 130°C, such as 96°C ℃~106℃.
- 根据权利要求1-4任一项所述的电池隔膜,其特征在于,The battery separator according to any one of claims 1-4, characterized in that,所述第二单体中所述极性基团为酯基或酰胺;The polar group in the second monomer is an ester group or an amide;可选地,所述第二单体包括N,N-亚甲基双丙烯酰胺和/或甲基丙烯酸丙烯酯。Optionally, the second monomer includes N,N-methylenebisacrylamide and/or acrylate methacrylate.
- 根据权利要求1-5任一项所述的电池隔膜,其特征在于,所述水溶性高分子聚合物中:所述第一结构单元和所述第二结构单元的数量之比为(85-95):(5-15),例如(87-93):(7-13),诸如(89-91):(9-11)。The battery separator according to any one of claims 1-5, characterized in that, in the water-soluble high molecular polymer: the ratio of the number of the first structural unit to the second structural unit is (85- 95):(5-15), for example (87-93):(7-13), such as (89-91):(9-11).
- 根据权利要求1-6任一项所述的电池隔膜,其特征在于,所述涂层仅覆盖所述基膜的一个表面。The battery separator according to any one of claims 1-6, wherein the coating only covers one surface of the base film.
- 根据权利要求1-7任一项所述的电池隔膜,其特征在于,所述涂层的厚度为2μm~4μm,例如2.5μm~3.5μm,诸如3μm。The battery separator according to any one of claims 1-7, characterized in that, the thickness of the coating is 2 μm˜4 μm, for example 2.5 μm˜3.5 μm, such as 3 μm.
- 根据权利要求1-8任一项所述的电池隔膜,其特征在于,所述涂层还包括陶瓷颗粒和分散剂;所述陶瓷颗粒、所述粘合剂以及所述分散剂的重量比为(90~96):(3~7):(1~3),例如(90~92):(5~7):(1~3),诸如(92~96):(3~4):(1~3);The battery separator according to any one of claims 1-8, wherein the coating further comprises ceramic particles and a dispersant; the weight ratio of the ceramic particles, the binder and the dispersant is: (90~96):(3~7):(1~3), for example (90~92):(5~7):(1~3), such as (92~96):(3~4): (1~3);可选地,所述陶瓷颗粒包括氧化铝、氧化硅、氧化钛、氧化镁、氧化锆及勃姆石中的至少一种;Optionally, the ceramic particles include at least one of alumina, silica, titania, magnesia, zirconia and boehmite;可选地,所述陶瓷颗粒的中位粒径为0.1μm~1μm,例如0.3μm~0.8μm,诸如 0.4μm~0.6μm,比表面积为2m 2/g~50m 2/g,例如8m 2/g~45m 2/g,诸如19m 2/g~26m 2/g之间; Optionally, the median particle diameter of the ceramic particles is 0.1 μm-1 μm, such as 0.3 μm-0.8 μm, such as 0.4 μm-0.6 μm, and the specific surface area is 2 m 2 /g-50 m 2 /g, such as 8 m 2 /g g~45m 2 /g, such as between 19m 2 /g~26m 2 /g;可选地,所述分散剂包括聚丙烯酸铵、聚丙烯酸钠及六偏磷酸钠中的至少一种。Optionally, the dispersant includes at least one of ammonium polyacrylate, sodium polyacrylate and sodium hexametaphosphate.
- 根据权利要求1-9任一项所述的电池隔膜,其特征在于,所述基膜的材料包括聚乙烯和/或聚丙烯;The battery separator according to any one of claims 1-9, wherein the material of the base film comprises polyethylene and/or polypropylene;可选地,所述基膜的孔隙率为35%~60%,例如40%~55%,诸如46%~49%;Optionally, the porosity of the base film is 35%-60%, such as 40%-55%, such as 46%-49%;可选地,所述基膜的厚度为5μm~25μm,例如9μm~21μm,诸如13μm~18μm。Optionally, the thickness of the base film is 5 μm-25 μm, for example 9 μm-21 μm, such as 13 μm-18 μm.
- 一种二次电池,其特征在于,所述二次电池包括正极极片、负极极片以及位于所述正极极片和所述负极极片之间的权利要求1-10任一项所述的电池隔膜。A secondary battery, characterized in that the secondary battery comprises a positive pole piece, a negative pole piece, and the battery according to any one of claims 1-10 located between the positive pole piece and the negative pole piece. battery separator.
- 根据权利要求11所述的二次电池,其特征在于,所述电池隔膜与所述正极极片、所述负极极片通过热压贴合。The secondary battery according to claim 11, wherein the battery separator is bonded to the positive electrode sheet and the negative electrode sheet by hot pressing.
- 一种制备电池隔膜涂层的浆料,其特征在于,所述制备电池隔膜涂层的浆料包括陶瓷颗粒、粘合剂、分散剂及溶剂;A slurry for preparing a battery separator coating, characterized in that the slurry for preparing a battery separator coating includes ceramic particles, a binder, a dispersant and a solvent;所述粘合剂包括水溶性高分子聚合物,所述水溶性高分子聚合物含有第一结构单元和第二结构单元;The adhesive includes a water-soluble high molecular polymer, and the water-soluble high molecular polymer contains a first structural unit and a second structural unit;其中,形成所述第一结构单元的第一单体为具有一个极性基团和一个碳碳双键官能团的单体,且所述第一单体的均聚物的玻璃化转变温度≥90℃;Wherein, the first monomer forming the first structural unit is a monomer having a polar group and a carbon-carbon double bond functional group, and the homopolymer of the first monomer has a glass transition temperature ≥ 90 ℃;形成所述第二结构单元的第二单体为具有极性基团和至少两个碳碳双键官能团的单体。The second monomer forming the second structural unit is a monomer having a polar group and at least two carbon-carbon double bond functional groups.
- 根据权利要求13所述的浆料,其特征在于,所述水溶性高分子聚合物的重均分子量为20万~60万,例如24万~57万,诸如30万~47万,例如36万~41万。The slurry according to claim 13, characterized in that, the weight average molecular weight of the water-soluble polymer is 200,000-600,000, such as 240,000-570,000, such as 300,000-470,000, such as 360,000 ~410,000.
- 根据权利要求13或14所述的浆料,其特征在于,所述第一单体包括丙烯酸、甲基丙烯酸、丙烯酰胺、丙烯腈、甲基丙烯酸甲酯、甲基丙烯酰胺以及苯乙烯中的至少一种。The slurry according to claim 13 or 14, wherein the first monomer comprises acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methyl methacrylate, methacrylamide and styrene at least one.
- 根据权利要求13-15任一项所述的浆料,其特征在于,所述第一单体的均聚物的玻璃化转变温度为90℃~150℃,例如93℃~130℃,诸如96℃~106℃。The slurry according to any one of claims 13-15, characterized in that the homopolymer of the first monomer has a glass transition temperature of 90°C to 150°C, such as 93°C to 130°C, such as 96°C ℃~106℃.
- 根据权利要求13-16任一项所述的浆料,其特征在于,The slurry according to any one of claims 13-16, characterized in that,所述第二单体中所述极性基团为酯基或酰胺;The polar group in the second monomer is an ester group or an amide;可选地,所述第二单体包括N,N-亚甲基双丙烯酰胺和/或甲基丙烯酸丙烯酯。Optionally, the second monomer includes N,N-methylenebisacrylamide and/or acrylate methacrylate.
- 根据权利要求13-17任一项所述的浆料,其特征在于,所述水溶性高分子聚合物中:所述第一结构单元和所述第二结构单元的数量之比为(85-95):(5-15),例如(87-93):(7-13),诸如(89-91):(9-11)。The slurry according to any one of claims 13-17, characterized in that, in the water-soluble polymer: the ratio of the number of the first structural unit to the second structural unit is (85- 95):(5-15), for example (87-93):(7-13), such as (89-91):(9-11).
- 根据权利要求13-18任一项所述的浆料,其特征在于,所述陶瓷颗粒、所述粘 合剂以及所述分散剂的重量比为(90~96):(3~7):(1~3),例如(90~92):(5~7):(1~3),诸如(92~96):(3~4):(1~3);The slurry according to any one of claims 13-18, wherein the weight ratio of the ceramic particles, the binder and the dispersant is (90~96):(3~7): (1~3), for example (90~92):(5~7):(1~3), such as (92~96):(3~4):(1~3);可选地,所述陶瓷颗粒包括氧化铝、氧化硅、氧化钛、氧化镁、氧化锆及勃姆石中的至少一种;Optionally, the ceramic particles include at least one of alumina, silica, titania, magnesia, zirconia and boehmite;可选地,所述陶瓷颗粒的中位粒径为0.1μm~1μm,例如0.3μm~0.8μm,诸如0.4μm~0.6μm,比表面积为2m 2/g~50m 2/g,例如8m 2/g~45m 2/g,诸如19m 2/g~26m 2/g之间; Optionally, the median particle diameter of the ceramic particles is 0.1 μm-1 μm, such as 0.3 μm-0.8 μm, such as 0.4 μm-0.6 μm, and the specific surface area is 2 m 2 /g-50 m 2 /g, such as 8 m 2 /g g~45m 2 /g, such as between 19m 2 /g~26m 2 /g;可选地,所述分散剂包括聚丙烯酸铵、聚丙烯酸钠及六偏磷酸钠中的至少一种;Optionally, the dispersant includes at least one of ammonium polyacrylate, sodium polyacrylate and sodium hexametaphosphate;可选地,所述溶剂包括水和乙醇。Optionally, the solvent includes water and ethanol.
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