CN117060008A - Cold-pressed adhesive coating diaphragm at normal temperature and preparation method thereof - Google Patents
Cold-pressed adhesive coating diaphragm at normal temperature and preparation method thereof Download PDFInfo
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- CN117060008A CN117060008A CN202311166289.XA CN202311166289A CN117060008A CN 117060008 A CN117060008 A CN 117060008A CN 202311166289 A CN202311166289 A CN 202311166289A CN 117060008 A CN117060008 A CN 117060008A
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- 238000000576 coating method Methods 0.000 title claims abstract description 47
- 239000011248 coating agent Substances 0.000 title claims abstract description 44
- 230000001070 adhesive effect Effects 0.000 title claims abstract description 33
- 239000000853 adhesive Substances 0.000 title claims abstract description 32
- 238000002360 preparation method Methods 0.000 title abstract description 6
- 239000000178 monomer Substances 0.000 claims abstract description 47
- 239000000839 emulsion Substances 0.000 claims abstract description 34
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 239000002904 solvent Substances 0.000 claims abstract description 13
- 239000003999 initiator Substances 0.000 claims abstract description 12
- 238000003825 pressing Methods 0.000 claims abstract description 12
- 229920000058 polyacrylate Polymers 0.000 claims abstract description 11
- 239000002033 PVDF binder Substances 0.000 claims description 37
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 30
- 229920001577 copolymer Polymers 0.000 claims description 29
- 239000006255 coating slurry Substances 0.000 claims description 21
- -1 fluoroalkyl acrylate Chemical compound 0.000 claims description 21
- 239000004743 Polypropylene Substances 0.000 claims description 16
- 229920001155 polypropylene Polymers 0.000 claims description 16
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 15
- 239000002270 dispersing agent Substances 0.000 claims description 13
- 239000002562 thickening agent Substances 0.000 claims description 13
- 239000000080 wetting agent Substances 0.000 claims description 13
- 239000011230 binding agent Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 11
- 238000001035 drying Methods 0.000 claims description 9
- 238000002156 mixing Methods 0.000 claims description 9
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 7
- 229910052731 fluorine Inorganic materials 0.000 claims description 7
- 239000011737 fluorine Substances 0.000 claims description 7
- 238000006116 polymerization reaction Methods 0.000 claims description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 6
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 claims description 4
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical group [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims description 4
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 claims description 4
- CRSBERNSMYQZNG-UHFFFAOYSA-N 1 -dodecene Natural products CCCCCCCCCCC=C CRSBERNSMYQZNG-UHFFFAOYSA-N 0.000 claims description 3
- SNRUBQQJIBEYMU-UHFFFAOYSA-N Dodecane Natural products CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 claims description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 3
- 239000005977 Ethylene Substances 0.000 claims description 3
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 3
- 229920002125 Sokalan® Polymers 0.000 claims description 3
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 3
- 229940069096 dodecene Drugs 0.000 claims description 3
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000004584 polyacrylic acid Substances 0.000 claims description 3
- 229920000570 polyether Polymers 0.000 claims description 3
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 3
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 3
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 claims description 3
- JAHNSTQSQJOJLO-UHFFFAOYSA-N 2-(3-fluorophenyl)-1h-imidazole Chemical compound FC1=CC=CC(C=2NC=CN=2)=C1 JAHNSTQSQJOJLO-UHFFFAOYSA-N 0.000 claims description 2
- WROUWQQRXUBECT-UHFFFAOYSA-N 2-ethylacrylic acid Chemical compound CCC(=C)C(O)=O WROUWQQRXUBECT-UHFFFAOYSA-N 0.000 claims description 2
- 239000002202 Polyethylene glycol Substances 0.000 claims description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 2
- 150000008431 aliphatic amides Chemical class 0.000 claims description 2
- 150000001733 carboxylic acid esters Chemical class 0.000 claims description 2
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 2
- 150000002148 esters Chemical class 0.000 claims description 2
- 239000000194 fatty acid Substances 0.000 claims description 2
- 229930195729 fatty acid Natural products 0.000 claims description 2
- 150000004665 fatty acids Chemical class 0.000 claims description 2
- 239000001530 fumaric acid Substances 0.000 claims description 2
- 239000011261 inert gas Substances 0.000 claims description 2
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 claims description 2
- 239000011976 maleic acid Substances 0.000 claims description 2
- LVHBHZANLOWSRM-UHFFFAOYSA-N methylenebutanedioic acid Natural products OC(=O)CC(=C)C(O)=O LVHBHZANLOWSRM-UHFFFAOYSA-N 0.000 claims description 2
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 2
- 229920001223 polyethylene glycol Polymers 0.000 claims description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 2
- 239000001993 wax Substances 0.000 claims description 2
- 239000003973 paint Substances 0.000 claims 1
- 238000007334 copolymerization reaction Methods 0.000 abstract description 6
- 238000007731 hot pressing Methods 0.000 abstract description 6
- 230000000052 comparative effect Effects 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000001878 scanning electron micrograph Methods 0.000 description 4
- 239000012528 membrane Substances 0.000 description 3
- PNXMTCDJUBJHQJ-UHFFFAOYSA-N propyl prop-2-enoate Chemical compound CCCOC(=O)C=C PNXMTCDJUBJHQJ-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- LYRFLYHAGKPMFH-UHFFFAOYSA-N octadecanamide Chemical group CCCCCCCCCCCCCCCCCC(N)=O LYRFLYHAGKPMFH-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 150000003254 radicals Chemical class 0.000 description 2
- 229940037312 stearamide Drugs 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- DCXXMTOCNZCJGO-UHFFFAOYSA-N tristearoylglycerol Chemical compound CCCCCCCCCCCCCCCCCC(=O)OCC(OC(=O)CCCCCCCCCCCCCCCCC)COC(=O)CCCCCCCCCCCCCCCCC DCXXMTOCNZCJGO-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 125000005250 alkyl acrylate group Chemical group 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- VBICKXHEKHSIBG-UHFFFAOYSA-N beta-monoglyceryl stearate Natural products CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO VBICKXHEKHSIBG-UHFFFAOYSA-N 0.000 description 1
- 238000005524 ceramic coating Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- LNMQRPPRQDGUDR-UHFFFAOYSA-N hexyl prop-2-enoate Chemical compound CCCCCCOC(=O)C=C LNMQRPPRQDGUDR-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- PBOSTUDLECTMNL-UHFFFAOYSA-N lauryl acrylate Chemical compound CCCCCCCCCCCCOC(=O)C=C PBOSTUDLECTMNL-UHFFFAOYSA-N 0.000 description 1
- 229940057995 liquid paraffin Drugs 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000010526 radical polymerization reaction Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 238000009736 wetting Methods 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
- H01M50/411—Organic material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Cell Separators (AREA)
Abstract
The invention discloses a normal-temperature cold-pressing adhesive coating diaphragm and a preparation method thereof, wherein the normal-temperature cold-pressing adhesive coating diaphragm is prepared based on a copolymerization emulsion, and the copolymerization emulsion comprises the following components: the composition comprises (by mass parts) polyacrylate, fluoroethylenically unsaturated monomer, ethylenically unsaturated monomer, other monomer, solvent and initiator, wherein the ratio of the polyacrylate to the fluoroethylenically unsaturated monomer to the other monomer is (50-100): (10-50): (10-50): (1-10): (50-100): (0.01-0.1), the normal-temperature cold-pressing adhesive coating diaphragm can be adhered with the pole piece under normal-temperature cold pressure, and the problem that the diaphragm can be adhered with the pole piece after hot pressing is solved.
Description
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a normal-temperature cold-pressing adhesive coating diaphragm and a preparation method thereof.
Background
The separator is one of the key components of the secondary battery, and is required to prevent contact between the positive electrode and the negative electrode and allow migration of ions between the positive electrode and the negative electrode. With the rapid development of battery technology, conventional separators composed of a polyolefin-based film and a ceramic coating have failed to meet the needs of people, and functional coatings that can improve the performance of the separators are gradually appeared on the market. Among them, an adhesive coating capable of closely adhering the separator and the pole piece and reducing the interface resistance thereof is one of typical representative of a separator functional coating. At present, the coating is usually composed of PVDF, which has certain crystallinity and can show adhesiveness when heated, but the adhesiveness of the PVDF diaphragm is relatively poor, so that on one hand, the performance of the diaphragm can be effectively improved, and on the other hand, the PVDF diaphragm has certain limitation. For example, the membrane with the coating needs to be adhered to the pole piece after hot pressing, and the process cost is increased to a certain extent. Therefore, there is still a great room for expansion in the field of research of low-temperature adhesive coating for secondary battery separators.
Disclosure of Invention
In view of the shortcomings of the prior art, the invention aims to provide a copolymerization emulsion.
It is another object of the present invention to provide a process for preparing the above-mentioned copolymer emulsion.
It is another object of the present invention to provide a functional coating slurry.
Another object of the present invention is to provide a cold-pressed adhesive coated separator at normal temperature.
Another object of the present invention is to provide a method for preparing the above-mentioned cold-pressed adhesive coated separator at normal temperature.
The aim of the invention is achieved by the following technical scheme.
A copolymer emulsion comprising: the composition comprises (by mass parts) polyacrylate, fluoroethylenically unsaturated monomer, ethylenically unsaturated monomer, other monomer, solvent and initiator, wherein the ratio of the polyacrylate to the fluoroethylenically unsaturated monomer to the other monomer is (50-100): (10-50): (10-50): (1-10): (50-100): (0.01-0.1), wherein the other monomer is an unsaturated carboxylic ester monomer, and the initiator is potassium persulfate.
In the above-mentioned embodiments, the weight average molecular weight of the polyacrylate is 20000 to 40000.
In the above technical scheme, the fluorine-containing ethylenically unsaturated monomer is one or a mixture of more of tetrafluoroethylene, fluorinated alkyl acrylate, fluorinated aryl acrylate and fluorinated aralkyl acrylate.
In the above technical scheme, the ethylenically unsaturated monomer is one or a mixture of several of ethylene, maleic acid, fumaric acid, itaconic acid and 2-ethyl acrylic acid.
In the above technical scheme, the other monomer is one or a mixture of more of propyl acrylate, hexyl acrylate and lauryl acrylate.
In the above technical solution, the solvent is water.
The preparation method of the copolymer emulsion comprises the following steps:
step 1, mixing polypropylene alcohol with a solvent to obtain a polypropylene alcohol solution;
and 2, introducing inert gas to remove oxygen in the polypropylene alcohol solution, mixing the polypropylene alcohol solution, the fluorine-containing ethylenically unsaturated monomer, the ethylenically unsaturated monomer, other monomers and an initiator, and carrying out polymerization under the condition of stirring to obtain the copolymer emulsion.
In the step 2, the temperature of the polymerization reaction is 50-80 ℃, and the time of the polymerization reaction is 2-5 h.
In step 2, the stirring speed is 200-300 rpm.
In step 2, the initiator is decomposed into free radicals in the polymerization reaction, the free radicals are introduced into the molecular chain of the polypropylene alcohol, the ethylenically unsaturated monomer is initiated, and the ethylenically unsaturated monomer and other monomers undergo free radical polymerization and are grafted to the polypropylene alcohol.
The copolymer emulsion is a polypropylene alcohol copolymer emulsion, and is obtained by graft copolymerization of a polypropylene alcohol main chain, fluorine-containing ethylenically unsaturated monomers, ethylenically unsaturated monomers and other monomers.
A functional coating slurry comprising: water, a dispersing agent, polyvinylidene fluoride (PVDF), a copolymerization emulsion, a thickening agent, a wetting agent and a binder, wherein the water, the dispersing agent, the polyvinylidene fluoride (PVDF), the copolymerization emulsion, the thickening agent, the wetting agent and the binder are mixed according to the mass parts (50-60): (0.3-0.4): (7-8): (20-30): (6-7): (0.1-0.2): (4-5).
In the technical scheme, the dispersing agent is one or a mixture of more of fatty acids, aliphatic amides, esters and low-molecular waxes.
In the technical scheme, the thickener is one or a mixture of more of polyvinyl alcohol, polyethylene glycol, sodium carboxymethyl cellulose and polyvinylpyrrolidone.
In the above technical scheme, the binder is one or a mixture of more of polyacrylic acid, polyacrylate and polyacrylonitrile.
In the technical scheme, the wetting agent is dodecene glycol polyether.
In the technical scheme, the dispersing agent is one or a mixture of more of vinyl bis-stearamide, stearic acid monoglyceride, tristearin and liquid paraffin.
A method of preparing a functional coating slurry comprising: mixing water, a dispersing agent and polyvinylidene fluoride (PVDF), stirring for 0.5-1 h to uniformity, adding the copolymer emulsion, a thickening agent, a wetting agent and a binder, and stirring for 0.5-1 h to uniformity to obtain the functional coating slurry.
A cold-pressed adhesive coated separator at normal temperature, comprising: the coating is formed by coating functional coating slurry and then drying.
A method of preparing a cold-pressed adhesive coated separator at room temperature, comprising: and coating the functional coating slurry on one or two sides of the base film to form a water-based coating, and drying to remove water in the water-based coating, thereby obtaining the normal-temperature cold-pressing adhesive coating diaphragm.
In the technical scheme, the drying temperature is 50-60 ℃ and the drying time is 5-10 min.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, water is used as a solvent, PVDF and copolymer emulsion are used as film forming components, after water is evaporated under the action of a certain temperature, the functional coating slurry forms a coating on the surface of a base film, the bonding force between a normal-temperature cold-pressing bonding coating diaphragm and a pole piece is increased due to the good interface bonding effect of PVDF, the copolymer emulsion enables the normal-temperature cold-pressing bonding coating diaphragm to have the bonding property equal to that of hot pressing at the normal temperature and the cold pressure, a thickener can increase the consistency of the functional coating slurry, the rheological property of the functional coating slurry is regulated, wetting molecules in a wetting agent are directionally arranged on the surface of solid PVDF, the surface energy of the water is reduced, and PVDF is dispersed in the water to form a stable suspension, so that the functional coating slurry is favorable for forming a film layer with good quality;
2. the normal-temperature cold-pressing adhesive coating diaphragm can be adhered with the pole piece at normal temperature and cold pressure, and the problem that the diaphragm and the pole piece can be adhered after hot pressing is solved.
Drawings
FIG. 1 is an SEM image of a PVDF coated separator prepared in comparative example 1;
fig. 2 is an SEM image of the room temperature cold-pressed adhesive coated separator prepared in example 1.
Detailed Description
The technical scheme of the invention is further described below with reference to specific embodiments.
The raw materials and home information involved in the following examples are as follows:
propyl acrylate, a company of pharmaceutical chemicals, limited, lakubei zifei;
potassium persulfate, perpetual chemical industry;
polyvinylidene fluoride, a material of blue sky fluoride limited company.
The instruments and their model information involved in the following examples are as follows:
the type of the stirrer is a double-planetary high-viscosity stirrer;
the coater is a new and new high-speed micro gravure coater.
The water in the following examples is deionized water.
The matrix in the examples described below is a polyolefin film.
Examples 1 to 3
A copolymer emulsion comprising: the weight average molecular weight of the polyacrylate is 28000-30000, the fluorine-containing ethylenically unsaturated monomer, the ethylenically unsaturated monomer, other monomers, the solvent and the initiator are mixed according to the mass parts, wherein the ratio of the polyacrylate to the fluorine-containing ethylenically unsaturated monomer to the other monomers to the solvent to the initiator is 80:25:25:5:80:0.05, in this example the fluoroethylenically unsaturated monomer is tetrafluoroethylene, the ethylenically unsaturated monomer is ethylene, the other monomer is propyl acrylate, the solvent is water, and the initiator is potassium persulfate.
The preparation method of the copolymer emulsion comprises the following steps:
step 1, mixing polypropylene alcohol with a solvent to obtain a polypropylene alcohol solution;
and 2, introducing argon to remove oxygen in the polypropylene alcohol solution, mixing the polypropylene alcohol solution, the fluorine-containing ethylenically unsaturated monomer, the ethylenically unsaturated monomer, other monomers and the initiator, and stirring at 75 ℃ at a speed of 220rpm for polymerization for 2.5 hours to obtain the copolymer emulsion.
The resulting copolymer emulsion was dried to obtain polymer particles, which were tested to have a spherical structure, a particle diameter D50 of 4.9 μm and a glass transition temperature of 39.18 ℃.
A functional coating slurry comprising: the water, the dispersing agent, the polyvinylidene fluoride (PVDF), the copolymer emulsion, the thickening agent, the wetting agent and the binding agent, wherein the weight portion ratio of the water, the dispersing agent, the polyvinylidene fluoride (PVDF), the copolymer emulsion, the thickening agent, the wetting agent and the binding agent is X, in the embodiment, the thickening agent is sodium carboxymethyl cellulose, the binding agent is polyacrylic acid, the wetting agent is dodecene glycol polyether, and the dispersing agent is stearamide. The method for preparing the functional coating slurry comprises the following steps: mixing water, a dispersing agent and polyvinylidene fluoride (PVDF), stirring for 1h to uniformity, adding the copolymer emulsion, a thickening agent, a wetting agent and a binder, and stirring for 0.5h to uniformity to obtain the functional coating slurry.
| Examples | X |
| Example 1 | 50：0.3：7：20：6：0.1：4 |
| Example 2 | 55：0.3：7：25：6：0.1：4 |
| Example 3 | 60：0.3：8：30：6：0.1：4 |
The method for preparing the normal-temperature cold-pressing adhesive coating diaphragm comprises the following steps: and (3) coating the functional coating slurry on one surface of the base film in a micro gravure roll coating mode to form a water-based coating with the thickness of 2um, and drying in an oven at 50 ℃ for 5min to remove water in the water-based coating, so as to obtain the normal-temperature cold-pressing adhesive coating diaphragm.
Comparative example 1
A method for producing a PVDF coated separator was substantially the same as the "method for producing a cold-pressed adhesive coated separator at room temperature" in example 1, except that the functional coating paste of this comparative example was not added with the copolymer emulsion.
Comparative example 2
A method for producing a PVDF coated separator was substantially the same as the "method for producing a cold-pressed adhesive coated separator at room temperature" in example 2, except that the functional coating paste of this comparative example was not added with the copolymer emulsion.
Comparative example 3
A method for producing a PVDF coated separator was substantially the same as the "method for producing a cold-pressed adhesive coated separator at room temperature" in example 3, except that the functional coating paste of this comparative example was not added with the copolymer emulsion.
Test results of the coatings prepared in examples 1 to 3, the cold-pressed adhesive coating films at room temperature, and the coatings prepared in comparative examples 1 to 3, PVDF coating films:
TABLE 1
As can be seen from Table 1, the adhesive force of the pole piece (purchased from Shenzhen lithium energy science and technology Co., ltd., negative Electrode: CC-9, positive Electrode: TOB-electric) of the PVDF coating diaphragm prepared in example 3 at normal temperature is highest, which indicates that the diaphragm is difficult to separate from the pole piece, the adhesive strength is high, while the adhesive force of the pole piece of the PVDF coating diaphragm prepared in comparative example 2 at normal temperature is minimum, which indicates that the diaphragm is easy to separate from the pole piece, and the adhesive strength is low; the adhesive coated membrane prepared in the normal temperature cold pressing mode and prepared in the examples 1-3 has better pole piece adhesive force than the PVDF coated membrane prepared in the comparative examples 1-3 under the hot pressing mode at normal temperature and 80 ℃.
The functional coating slurry takes water as a solvent, PVDF and copolymer emulsion are taken as film forming components, after the water is evaporated under the condition of heating, the coating slurry is formed into a film-shaped coating, the PVDF increases the adhesive force of a coating diaphragm, and the copolymer emulsion enables the diaphragm to have the adhesive property equal to that of the PVDF coating diaphragm prepared without adding the copolymer emulsion under the condition of normal temperature and cold pressure at 80 ℃ in hot pressing.
As shown in fig. 1, which is an SEM image of the PVDF coated separator prepared in comparative example 1, uniform distribution of PVDF powder can be observed; FIG. 2 is an SEM image of a cold-pressed adhesive coated separator at room temperature prepared in example 1, and it was observed that there was a copolymer in a sphere distribution in addition to PVDF.
The foregoing has described exemplary embodiments of the invention, it being understood that any simple variations, modifications, or other equivalent arrangements which would not unduly obscure the invention may be made by those skilled in the art without departing from the spirit of the invention.
Claims (10)
1. A copolymer emulsion comprising: the composition comprises (by mass parts) polyacrylate, fluoroethylenically unsaturated monomer, ethylenically unsaturated monomer, other monomer, solvent and initiator, wherein the ratio of the polyacrylate to the fluoroethylenically unsaturated monomer to the other monomer is (50-100): (10-50): (10-50): (1-10): (50-100): (0.01-0.1), wherein the other monomer is an unsaturated carboxylic ester monomer, and the initiator is potassium persulfate.
2. The copolymer emulsion of claim 1, wherein the fluoroethylenically unsaturated monomer is one or a mixture of several of tetrafluoroethylene, fluoroalkyl acrylate, fluoroaryl acrylate and fluoroaryl acrylate, the ethylenically unsaturated monomer is one or a mixture of several of ethylene, maleic acid, fumaric acid, itaconic acid and 2-ethyl acrylic acid, and the solvent is water.
3. A method of preparing a co-emulsion according to claim 1 or 2, comprising the steps of:
step 1, mixing polypropylene alcohol with a solvent to obtain a polypropylene alcohol solution;
and 2, introducing inert gas to remove oxygen in the polypropylene alcohol solution, mixing the polypropylene alcohol solution, the fluorine-containing ethylenically unsaturated monomer, the ethylenically unsaturated monomer, other monomers and an initiator, and carrying out polymerization under the condition of stirring to obtain the copolymer emulsion.
4. The method according to claim 3, wherein in the step 2, the polymerization reaction is carried out at a temperature of 50 to 80℃for a period of 2 to 5 hours, and the stirring speed is 200 to 300rpm.
5. A functional coating slurry, comprising: the water-based paint comprises water, a dispersing agent, polyvinylidene fluoride, the copolymer emulsion, a thickening agent, a wetting agent and a binder, wherein the water, the dispersing agent, the polyvinylidene fluoride, the copolymer emulsion, the thickening agent, the wetting agent and the binder are in a ratio of (50-60) in parts by weight: (0.3-0.4): (7-8): (20-30): (6-7): (0.1-0.2): (4-5).
6. The functional coating paste according to claim 5, wherein the dispersing agent is one or a mixture of several of fatty acids, aliphatic amides, esters and low molecular waxes, the thickener is one or a mixture of several of polyvinyl alcohol, polyethylene glycol, sodium carboxymethyl cellulose and polyvinylpyrrolidone, the binder is one or a mixture of several of polyacrylic acid, polyacrylate and polyacrylonitrile, and the wetting agent is dodecene glycol polyether.
7. A method of preparing a functional coating slurry according to claim 5 or 6, comprising: mixing water, a dispersing agent and polyvinylidene fluoride, stirring for 0.5-1 h to uniformity, adding the copolymer emulsion, a thickening agent, a wetting agent and a binder, and stirring for 0.5-1 h to uniformity to obtain the functional coating slurry.
8. A cold-pressed adhesive coated separator at normal temperature, comprising: the coating is formed by coating functional coating slurry and then drying.
9. The method for preparing a cold-pressed adhesive coated separator at normal temperature according to claim 8, comprising: and coating the functional coating slurry on one or two sides of the base film to form a water-based coating, and drying to remove water in the water-based coating, thereby obtaining the normal-temperature cold-pressing adhesive coating diaphragm.
10. The method according to claim 9, wherein the drying temperature is 50-60 ℃ and the drying time is 5-10 min.
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| CN202311166289.XA CN117060008A (en) | 2023-09-11 | 2023-09-11 | Cold-pressed adhesive coating diaphragm at normal temperature and preparation method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311166289.XA CN117060008A (en) | 2023-09-11 | 2023-09-11 | Cold-pressed adhesive coating diaphragm at normal temperature and preparation method thereof |
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