CN111900311A - Isolating membrane and manufacturing method thereof - Google Patents
Isolating membrane and manufacturing method thereof Download PDFInfo
- Publication number
- CN111900311A CN111900311A CN202010811439.8A CN202010811439A CN111900311A CN 111900311 A CN111900311 A CN 111900311A CN 202010811439 A CN202010811439 A CN 202010811439A CN 111900311 A CN111900311 A CN 111900311A
- Authority
- CN
- China
- Prior art keywords
- heat
- resistant layer
- manufacturing
- separator
- extension
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 44
- 239000012528 membrane Substances 0.000 title claims abstract description 19
- 239000000758 substrate Substances 0.000 claims abstract description 64
- 239000010954 inorganic particle Substances 0.000 claims abstract description 41
- 239000011230 binding agent Substances 0.000 claims abstract description 26
- 239000006255 coating slurry Substances 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims description 97
- 230000008569 process Effects 0.000 claims description 92
- 239000004743 Polypropylene Substances 0.000 claims description 39
- 229920001155 polypropylene Polymers 0.000 claims description 39
- 229920001577 copolymer Polymers 0.000 claims description 35
- 238000000576 coating method Methods 0.000 claims description 31
- 229920002689 polyvinyl acetate Polymers 0.000 claims description 30
- 239000011118 polyvinyl acetate Substances 0.000 claims description 30
- 239000011248 coating agent Substances 0.000 claims description 29
- 239000002243 precursor Substances 0.000 claims description 27
- 239000004698 Polyethylene Substances 0.000 claims description 25
- 229920000573 polyethylene Polymers 0.000 claims description 25
- 229920000131 polyvinylidene Polymers 0.000 claims description 25
- -1 polytetrafluoroethylene Polymers 0.000 claims description 24
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 16
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 16
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 14
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 14
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 12
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 10
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 8
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 7
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 7
- 239000004642 Polyimide Substances 0.000 claims description 7
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 7
- 229910002113 barium titanate Inorganic materials 0.000 claims description 7
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 7
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 7
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 7
- 229910052744 lithium Inorganic materials 0.000 claims description 7
- 239000011777 magnesium Substances 0.000 claims description 7
- 239000000395 magnesium oxide Substances 0.000 claims description 7
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 7
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 7
- 229910000480 nickel oxide Inorganic materials 0.000 claims description 7
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 claims description 7
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- 229920001721 polyimide Polymers 0.000 claims description 7
- 229920001451 polypropylene glycol Polymers 0.000 claims description 7
- 229920002620 polyvinyl fluoride Polymers 0.000 claims description 7
- 239000000377 silicon dioxide Substances 0.000 claims description 7
- 235000012239 silicon dioxide Nutrition 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 claims description 6
- 239000004800 polyvinyl chloride Substances 0.000 claims description 6
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 5
- 239000004952 Polyamide Substances 0.000 claims description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 5
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 5
- CJNBYAVZURUTKZ-UHFFFAOYSA-N hafnium(iv) oxide Chemical compound O=[Hf]=O CJNBYAVZURUTKZ-UHFFFAOYSA-N 0.000 claims description 5
- 229920002647 polyamide Polymers 0.000 claims description 5
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 4
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 claims description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 4
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 4
- 229910052746 lanthanum Inorganic materials 0.000 claims description 4
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 4
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims description 4
- 239000000347 magnesium hydroxide Substances 0.000 claims description 4
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims description 4
- ZQXSMRAEXCEDJD-UHFFFAOYSA-N n-ethenylformamide Chemical compound C=CNC=O ZQXSMRAEXCEDJD-UHFFFAOYSA-N 0.000 claims description 4
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 claims description 4
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 4
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 4
- 229920006149 polyester-amide block copolymer Polymers 0.000 claims description 3
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 3
- 239000000853 adhesive Substances 0.000 claims description 2
- 230000001070 adhesive effect Effects 0.000 claims description 2
- OTIXUSNHAKOJBX-UHFFFAOYSA-N 1-(aziridin-1-yl)ethanone Chemical compound CC(=O)N1CC1 OTIXUSNHAKOJBX-UHFFFAOYSA-N 0.000 claims 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims 1
- 239000000292 calcium oxide Substances 0.000 claims 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims 1
- 229920000193 polymethacrylate Polymers 0.000 claims 1
- 229910010271 silicon carbide Inorganic materials 0.000 claims 1
- 239000004408 titanium dioxide Substances 0.000 claims 1
- 239000011787 zinc oxide Substances 0.000 claims 1
- 230000035699 permeability Effects 0.000 abstract description 13
- 238000000926 separation method Methods 0.000 abstract description 4
- 230000000903 blocking effect Effects 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 65
- 238000002955 isolation Methods 0.000 description 17
- 238000001878 scanning electron micrograph Methods 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- 239000000523 sample Substances 0.000 description 11
- 239000002033 PVDF binder Substances 0.000 description 7
- 239000003792 electrolyte Substances 0.000 description 7
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 7
- 230000000704 physical effect Effects 0.000 description 7
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 7
- 229920001145 Poly(N-vinylacetamide) Polymers 0.000 description 6
- 239000002356 single layer Substances 0.000 description 6
- HMZNNQMHGDXAHG-UHFFFAOYSA-N 1-cyanoethenyl 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OC(=C)C#N HMZNNQMHGDXAHG-UHFFFAOYSA-N 0.000 description 5
- SMUVTFSHWISULV-UHFFFAOYSA-N methyl 2-methylprop-2-enoate;prop-2-enenitrile Chemical compound C=CC#N.COC(=O)C(C)=C SMUVTFSHWISULV-UHFFFAOYSA-N 0.000 description 5
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 3
- 229910004243 O3-PbTiO3 Inorganic materials 0.000 description 3
- 229910004293 O3—PbTiO3 Inorganic materials 0.000 description 3
- 229910020268 Pb1-xLaxZr1-y Inorganic materials 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052726 zirconium Inorganic materials 0.000 description 3
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000010622 cold drawing Methods 0.000 description 2
- 238000003618 dip coating Methods 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000007765 extrusion coating Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000007767 slide coating Methods 0.000 description 2
- 238000007764 slot die coating Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000004528 spin coating Methods 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 239000000080 wetting agent Substances 0.000 description 2
- BAPRUDZDYCKSOQ-RITPCOANSA-N (2s,4r)-1-acetyl-4-hydroxypyrrolidine-2-carboxylic acid Chemical compound CC(=O)N1C[C@H](O)C[C@H]1C(O)=O BAPRUDZDYCKSOQ-RITPCOANSA-N 0.000 description 1
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- DNGZVLPJDKEMQH-UHFFFAOYSA-N FC(=C(F)F)F.C=CC1=CC=CC=C1 Chemical group FC(=C(F)F)F.C=CC1=CC=CC=C1 DNGZVLPJDKEMQH-UHFFFAOYSA-N 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- DVWZQQXTOMQCCK-UHFFFAOYSA-N ethenyl acetate;prop-2-enenitrile Chemical compound C=CC#N.CC(=O)OC=C DVWZQQXTOMQCCK-UHFFFAOYSA-N 0.000 description 1
- 238000007756 gravure coating Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000007581 slurry coating method Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
Images
Landscapes
- Cell Separators (AREA)
Abstract
The invention discloses a separation film and a manufacturing method thereof, wherein the separation film comprises a substrate with a porous structure and a heat-resistant layer, and the heat-resistant layer is arranged on one side or two side surfaces of the substrate with the porous structure. The heat-resistant layer comprises a binder and a plurality of inorganic particles, wherein the coverage rate of the heat-resistant layer on the substrate is between 10% and 90%. The invention can avoid the inorganic particles in the coating slurry from blocking the micropores in the base material, so that the prepared isolating membrane has good air permeability and lower alternating current impedance. Meanwhile, the heat-resistant layer can still improve the heat resistance and the puncture strength of the isolating membrane and can also maintain lower water content.
Description
Technical Field
The present invention relates to a separator, and more particularly, to a porous separator having a heat-resistant layer containing inorganic particles.
Background
In response to the rapid development in the fields of Electric Vehicles (EV) and 3C, which are environmentally friendly, the demand for lithium ion battery energy storage systems with high energy density and power density is increasing. The separator is a polymer film applied to a lithium battery, and is interposed between a positive electrode and a negative electrode to prevent the electrodes from being short-circuited due to physical contact. Meanwhile, the microporous structure of the separation membrane allows free ions in the electrolyte to pass through the microporous structure, so that the battery generates voltage. Therefore, the stability of the separator directly affects the performance of the battery, and when the micropores in the separator are blocked, the total amount of the electrolyte that can be absorbed by the separator is reduced, which results in high internal resistance and low performance of the lithium battery.
The conventional dry-type method for preparing the porous isolation film comprises extruding molten plastic into a film, cooling and annealing to obtain a film precursor with a specific crystal form, and performing a cold stretching process and a hot stretching process to generate micropores in the film precursor, thereby obtaining the porous isolation film. However, the conventional porous separator has problems of poor heat resistance and poor puncture strength.
In the prior art, after a porous separator is prepared by the above method, a coating slurry containing inorganic particles is coated on the porous separator to enhance the desired properties of the separator, such as weather resistance, heat resistance, good mechanical properties, etc. The introduction of the inorganic particle heat-resistant layer can greatly improve the thermal stability of the isolating film. The isolating membrane with the inorganic particle heat-resistant layer can prevent the isolating membrane from generating large-scale thermal shrinkage under overcharge and high-temperature environments, so that the anode and the cathode in the battery are in large-scale short circuit.
However, in the conventional separator having an inorganic particle heat-resistant layer, which is formed by performing an extension process and then a coating process, the pores of the separator are easily covered by the coating slurry during the slurry coating process, which not only reduces the air permeability of the separator, but also reduces the amount of electrolyte that can be absorbed by the separator, thereby increasing the internal resistance of the lithium battery and reducing the performance of the battery. In addition, the moisture content of the isolation film is greatly improved due to the characteristic that the inorganic particles are easy to adsorb moisture. If the water content in the battery system is high, the battery performance is poor, which is not desirable in product application.
Therefore, there is still a need for a separator having an inorganic particle heat-resistant layer, which has good heat-resistant properties and puncture strength, but can maintain a suitable water content, good air permeability and low AC resistance.
Disclosure of Invention
In view of the above problems, the present invention provides a separator and a method for manufacturing the same. The manufacturing method comprises coating a heat-resistant coating slurry containing a binder and inorganic particles on a nonporous precursor substrate, and then performing an extension process to form a substrate with a porous structure and a heat-resistant layer. Accordingly, the inorganic particles in the coating slurry can be prevented from blocking the micropores in the substrate, so that the prepared barrier film has good air permeability and low AC impedance. Meanwhile, the heat-resistant layer can still improve the heat resistance and the puncture strength of the isolating membrane and can also maintain lower water content.
The invention provides an isolating membrane, which comprises a substrate with a porous structure and a heat-resistant layer, wherein the heat-resistant layer is arranged on one side or two side surfaces of the substrate. The heat-resistant layer includes a binder and a plurality of inorganic particles. Wherein, the coverage rate of the heat-resistant layer on the base material is between 10% and 90%.
According to an embodiment of the present invention, the heat-resistant layer forms a continuous network structure or a sea-island structure on the substrate.
According to an embodiment of the present invention, the thickness of the heat-resistant layer may be between 0.01 micrometers (μm) and 20 micrometers (μm).
According to an embodiment of the present invention, the heat-resistant layer includes 1 to 20 parts by weight of a binder and 80 to 99 parts by weight of inorganic particles.
According to an embodiment of the present invention, the particle size of the inorganic particles may be between 0.01 micrometers (μm) and 2 micrometers (μm).
According to an embodiment of the present invention, the heat-resistant layer is formed by applying a heat-resistant coating slurry onto the non-porous precursor substrate and then performing an extension process.
According to an embodiment of the present invention, the binder may be polyvinyl chloride (PVC), polyvinyl fluoride (PVF), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-tetrafluoroethylene (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride-trichloroethylene copolymer (PVA-HFP), polyvinylidene fluoride-trichloroethylene copolymer (PVDF-trichloroethylene), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVA-tetrafluoroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVDF-tetrafluoroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene chloride (polyvinylidene fluoride-tetrafluoroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene chloride (PVDF-tetrafluoroethylene copolymer), polyvinyl acetate (poly (acrylonitrile-methyl methacrylate) (pp-acrylonitrile), polyvinyl acetate (poly (methyl methacrylate) (PTFE-acrylonitrile), polyvinyl acetate (poly (acrylonitrile-methyl methacrylate) (pp), polyvinyl chloride (acrylonitrile-vinyl acetate) (poly (acrylonitrile-methyl methacrylate) (PTFE), poly (acrylonitrile-methyl methacrylate) (pp), poly (acrylonitrile-methyl methacrylate) (poly (acrylonitrile) (pp-methyl methacrylate) (pc-vinyl acetate) (pc-acrylonitrile) (pc-co-vinyl acetate) (pc-acrylonitrile) (pc-co-vinyl acetate) (pc-co-vinyl acetate (methyl methacrylate) (pc-co, At least one of Polyimide (PI), Styrene Butadiene Rubber (SBR), polyethylene oxide (PEO), polypropylene oxide (PPO), poly (N-vinylacetamide) (PNVA), and poly (N-vinylformamide) (PNVF), or a combination thereof
According to an embodiment of the present invention, the inorganic particles may be at least one of barium titanate (BaTiO3), lead zirconate titanate (Pb (Zr, Ti) O3, PZT), lead lanthanum zirconate titanate (Pb1-xLaxZr1-Y (ZrTiyO3), PLZT), lead magnesium niobate-lead titanate (Pb (Mg3, Nb2/3) O3-PbTiO3, PMN-PT), hafnium dioxide (HfO2), lithium titanate (SrTiO2), tin dioxide (SnO2), cerium dioxide (CeO2), magnesium oxide (MgO), magnesium hydroxide (Mg (oh)2), nickel oxide (NiO), calcium oxide (CaO), zinc oxide (ZnO), zirconium dioxide (ZrO2), silicon dioxide (SiO2), yttrium oxide (Y2O3), aluminum oxide (Al2O3), aluminum oxyhydroxide (alo (oh), silicon carbide (SiC), and titanium dioxide (TiO2), or a combination thereof.
The invention also provides a manufacturing method of the isolating membrane, which comprises the following steps: providing a nonporous precursor substrate; coating a heat-resistant coating slurry on one or both surfaces of the nonporous precursor substrate to form a heat-resistant coating, wherein the heat-resistant coating slurry comprises: a binder and a plurality of inorganic particles; carrying out an extension process on the nonporous precursor substrate with the heat-resistant coating to prepare an isolating membrane with a heat-resistant layer and a substrate with a porous structure; wherein the coverage rate of the heat-resistant layer on the substrate can be between 10% and 90%.
According to an embodiment of the manufacturing method of the present invention, the heat-resistant coating paste includes 1 to 20 parts by weight of the binder and 80 to 99 parts by weight of the inorganic particles.
According to an embodiment of the manufacturing method of the present invention, the heat-resistant coating paste may further include a solvent, and the solvent may be at least one of water, acetone, N-methylpyrrolidone (NMP), Dimethylacetamide (DMAC), and Dimethylsulfoxide (DMSO), or a combination thereof.
According to an embodiment of the manufacturing method of the present invention, the material of the non-porous precursor substrate may be polyethylene, polypropylene, polyester, polyamide, or a combination thereof.
According to an embodiment of the manufacturing method of the present invention, the extending process includes a first extending process extending along a first direction.
According to an embodiment of the manufacturing method of the present invention, the first extension process may include a cold extension process and a hot extension process.
According to an embodiment of the manufacturing method of the present invention, the cold drawing process may have a drawing temperature of 5 ℃ to 50 ℃ and a drawing magnification of 5% to 60%.
According to an embodiment of the manufacturing method of the present invention, the stretching temperature of the thermal stretching process may be between 80 ℃ and 160 ℃, and the stretching magnification may be between 80% and 400%.
According to an embodiment of the manufacturing method of the present invention, the extension process may further include a first retraction process retracting along the first direction, and a retraction magnification of the first retraction process may be between 0.1% and 30%.
According to another embodiment of the manufacturing method of the present invention, the extending process may optionally further include a second extending process extending along a second direction, and the second direction is perpendicular to the first direction.
According to another embodiment of the manufacturing method of the present invention, the extension temperature of the second direction extension process may be between 110 ℃ and 135 ℃, and the extension ratio may be between 10% and 150%.
According to another embodiment of the manufacturing method of the present invention, the extension process may optionally further include a second retraction process retracting along the first direction, and the retraction rate of the second retraction process may be between 5% and 50%.
The above summary is intended to provide a simplified summary of the disclosure in order to provide a basic understanding to the reader of the disclosure. This summary is not an extensive overview of the disclosure and is intended to neither identify key/critical elements of the embodiments nor delineate the scope of the embodiments. The basic spirit of the present invention and the technical means and embodiments adopted by the present invention will be easily understood by those skilled in the art after referring to the following embodiments.
Drawings
FIG. 1 is a SEM image of the surface of the isolation film of example 1 of the present invention at 200 magnifications.
FIG. 2 is a SEM image of the surface of the isolation film of example 1 of the present invention at 4,500 magnifications.
FIG. 3 is a SEM image of the surface of a separator of example 2 of the present invention at 1,000 times.
FIG. 4 is a SEM image of the surface of the isolation film of example 2 of the present invention at 4,500 magnifications.
FIG. 5 is a SEM image of a cross-section of a separator of example 2 of the present invention at 2,000 times.
FIG. 6 is a SEM image of the surface of the isolation film of example 3 of the present invention at 200 magnifications.
FIG. 7 is a SEM image of the surface of the isolation film of example 3 of the present invention at 600 magnifications.
FIG. 8 is a SEM image of the surface of the isolation film of example 4 of the present invention at 200 magnifications.
FIG. 9 is a SEM image of the surface of a separator of example 4 of the present invention at 1,000 magnifications.
FIG. 10 is a SEM image of the surface of the isolation film of example 5 of the present invention at 200 magnifications.
FIG. 11 is a SEM photograph of the surface of the isolation film of example 5 at 1,000 times.
FIG. 12 is a SEM image of the surface of the isolation film of example 6 of the present invention at 200 magnifications.
FIG. 13 is a SEM image of the surface of a separator of example 6 of the present invention at 1,000 magnifications.
FIG. 14 is a scanning electron microscope photograph at 1,000 times of the surface of the separator of comparative example 2 of the present invention.
Detailed Description
The advantages, features, and technical solutions of the present invention will be described in greater detail with reference to exemplary embodiments for easier understanding, and the present invention may be embodied in different forms, so should not be construed as limited to the embodiments set forth herein, but rather should be construed as providing embodiments that will provide a more thorough and complete understanding of the present disclosure and will fully convey the scope of the invention to those skilled in the art and that the present invention will only be defined by the appended claims.
Unless otherwise defined, all terms (including technical and scientific terms) and terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an overly idealized or overly formal sense unless expressly so defined herein.
In the present specification, the term "(meth) acrylic acid" refers to acrylic acid or methacrylic acid. The term "methyl acrylate" refers to an acrylate or a methyl acrylate.
The invention provides a separation film, which comprises a substrate with a porous structure and a heat-resistant layer, wherein the heat-resistant layer is arranged on one side or two side surfaces of the substrate.
In an embodiment of the present invention, the substrate having a porous structure in the separator may be a single-layer or multi-layer porous structure substrate of polyolefin, polyester, or polyamide, without particular limitation. In an embodiment of the present invention, the material of the substrate having a porous structure may be, for example, polyethylene, polypropylene, polyester or polyamide. The substrate with porous structure can be, for example, Polyethylene (PE) with single layer or polypropylene with single layer
(Polypropylene, PP), double layer polyethylene/Polypropylene (PE/PP), or triple layer Polypropylene/polyethylene/Polypropylene (PP/PE/PP), but is not limited thereto. In one embodiment of the present invention, the thickness of the substrate with porous structure may be between about 7 micrometers (μm) and 30 micrometers (μm), preferably between 9 micrometers (μm) and 25 micrometers (μm), the porosity thereof is between about 30% and 50%, and the pore size thereof is between about 0.01 micrometers (μm) and 0.1 micrometers (μm), preferably between about 0.01 micrometers (μm) and 0.05 micrometers (μm).
The heat-resistant layer of the present invention is formed by applying a heat-resistant coating slurry to a non-porous precursor substrate and then performing an extension process. The extension process may include one or more extension steps, and each extension step may extend in the same direction or in different directions without particular limitation. The extension steps may also be performed at different temperatures. The extension process may optionally include one or more retraction processes, which may be performed after the extension step is completed or may be performed simultaneously with the extension step.
The heat-resistant coating paste may include, for example, a binder and a plurality of inorganic particles, but is not limited thereto. In one embodiment of the present invention, the heat-resistant layer may include 1 to 20 parts by weight of a binder and 80 to 99 parts by weight of inorganic particles. In practice, other additives may be included in the heat resistant layer, intended to be defined in such a way as to illustrate the relative amounts of binder and particles.
The heat-resistant layer may be formed on the substrate in a continuous network structure or a sea-island structure, which does not entirely cover the surface of the substrate, but is not limited thereto. In an embodiment of the present invention, the coverage of the heat-resistant layer on the substrate may be between 10% and 90%, and preferably between 30% and 80%. When the coverage rate is too high, the air permeability and the alternating current impedance of the isolation film are affected, and the water content is also increased. When the coverage is too low, the heat resistance of the separator cannot be effectively improved. The thickness of the heat-resistant layer may be between 0.01 micrometers (μm) and 20 micrometers (μm), and preferably between 0.1 micrometers (μm) and 10 micrometers (μm). The voids between the inorganic particles form a plurality of micropores in the heat-resistant layer, and the pore size of the micropores may be between 0.01 micrometers (μm) and 50 micrometers (μm), and preferably between 0.1 micrometers (μm) and 40 micrometers (μm). The porosity of the heat-resistant layer may be between 10% and 95%, and preferably between 20% and 80%.
Suitable binders are not particularly limited, and a binder that is stable to the electrolyte of the battery and can bind the inorganic particles to the substrate may be used. In one embodiment of the present invention, the binder may be polyvinyl chloride (PVC), polyvinyl fluoride (PVF), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-tetrafluoroethylene (PVDF-HFP), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVDF-TFE), polyvinylidene fluoride-hexafluoropropylene (PVA-HFP), polyvinylidene fluoride-trichloroethylene copolymer (PVA-trichloroethylene), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVDF-trichloroethylene), polyvinylidene fluoride-tetrafluoroethylene chloride (polyvinylidene fluoride-tetrafluoroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene chloride (PVDF-tetrafluoroethylene copolymer), polyvinyl acetate (polyacrylonitrile-acrylonitrile), polyvinyl acetate (polyacrylonitrile-methyl methacrylate) (pp-acrylonitrile), polyvinyl acetate (polyacrylonitrile-methyl methacrylate) (PTFE-acrylonitrile), polyvinyl acetate (polyacrylonitrile-acrylonitrile) (pp-acrylonitrile copolymer (polyacrylonitrile), polyvinyl acetate (polyacrylonitrile (PTFE), polyvinyl acetate (polyacrylonitrile), polyvinyl acetate (polyacrylonitrile-methyl methacrylate) (PTFE), polyvinyl acetate (polyacrylonitrile (PTFE-acrylonitrile copolymer), polyvinyl acetate (polyacrylonitrile), polyvinyl acetate (polyacrylonitrile (pp-ethylene acetate (acrylonitrile copolymer (PTFE), polyvinyl acetate (polyacrylonitrile), polyvinyl acetate (polyacrylonitrile (pp-ethylene (acrylonitrile copolymer (PTFE), polyvinyl acetate (acrylonitrile (pp), polyvinyl acetate) (pp), polyvinyl acetate (acrylonitrile copolymer), polyvinyl acetate (acrylonitrile (PTFE), polyvinyl acetate) (pp), polyvinyl acetate (acrylonitrile (styrene-tetrafluoroethylene), Polyimide (PI), Styrene Butadiene Rubber (SBR), polyethylene oxide (PEO), polypropylene oxide (PPO), poly (N-vinylacetamide) (PNVA), or poly (N-vinylformamide) (PNVF), but is not limited thereto. The above-mentioned binders may be used alone or in combination of two or more.
Suitable inorganic particles are not particularly limited, and those known to be suitable for use in the field of separator films, for example, fine particles having a dielectric constant of not less than 5, can be used. In an embodiment of the present invention, the inorganic particles may be, for example, barium titanate (BaTiO3), lead zirconate titanate (Pb (Zr, Ti) O3, PZT), lead lanthanum zirconate titanate (Pb1-xLaxZr1-Y (ZrTiyO3), PLZT), lead magnesium niobate-lead titanate (Pb (Mg3, Nb2/3) O3-PbTiO3, PMN-PT), hafnium dioxide (HfO2), lithium titanate (SrTiO2), tin dioxide (SnO2), cerium dioxide (CeO2), magnesium oxide (MgO), magnesium hydroxide (Mg (oh)2), nickel oxide (NiO), calcium oxide (CaO), zinc oxide (ZnO), zirconium dioxide (ZrO2), silicon dioxide (SiO2), yttrium oxide (Y2O3), aluminum oxide (Al2O3), aluminum oxyhydroxide (alo (oh)), silicon carbide (SiC), or titanium dioxide (TiO2), but not limited thereto. The inorganic particles may be used alone or in combination of two or more.
The separator having a heat resistant layer according to the present invention may have physical properties required as a battery separator, such as a thermal shrinkage rate (130 c/1 hr) of not more than 30%, a water content of less than 550ppm, an air permeability (Gurley number) of less than 220sec, an ac impedance of less than 1.6 ohm-cm 2, and a puncture strength of more than 280 g.
The invention also provides a manufacturing method of the isolating membrane, which comprises the following steps: providing a nonporous precursor substrate; applying a heat-resistant coating slurry to one or both surfaces of a non-porous precursor substrate to form a heat-resistant coating, wherein the heat-resistant coating slurry comprises: a binder and a plurality of inorganic particles; carrying out an extension process on the nonporous precursor substrate with the heat-resistant coating to prepare an isolating membrane with a heat-resistant layer and a substrate with a porous structure; wherein, the coverage rate of the heat-resistant layer on the base material is between 10% and 90%. The heat-resistant layer may be formed on the substrate in a continuous network structure or a sea-island structure, which does not entirely cover the surface of the substrate, but is not limited thereto.
In one embodiment of the manufacturing method of the present invention, the material of the nonporous precursor substrate may be polyethylene, polypropylene, polyester, polyamide, or a combination thereof. The non-porous precursor substrate can be formed, for example, by extruding a polymer through an extruder, but is not limited thereto. The nonporous precursor substrate may be a monolayer film or a multilayer composite film, such as, but not limited to, a monolayer Polyethylene (PE), a monolayer Polypropylene (PP), a bilayer Polyethylene/Polypropylene (PE/PP), or a trilayer Polypropylene/Polyethylene/Polypropylene (PP/PE/PP).
In one embodiment of the manufacturing method of the present invention, the heat-resistant coating paste may include 1 to 20 parts by weight of the binder and 80 to 99 parts by weight of the inorganic particles. In practice, other additives may also be included in the heat-resistant coating slurry, intended to be defined in such a way as to illustrate the relative amounts of binder and particles.
The suitable binder is not particularly limited, and a binder that is stable to an electrolyte of the battery and can bind the inorganic particles to the substrate having the porous structure may be used. In one embodiment of the present invention, the binder may be polyvinyl chloride (PVC), polyvinyl fluoride (PVF), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-tetrafluoroethylene (PVDF-HFP), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVDF-TFE), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride-trichloroethylene copolymer (PVA-trichloroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene chloride (polyvinylidene fluoride-tetrafluoroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVDF-tetrafluoroethylene copolymer), polyvinylidene fluoride-tetrafluoroethylene chloride (PVDF-methacrylate copolymer), polyvinyl chloride (polyacrylonitrile-methacrylate), polyvinyl acetate (polyacrylonitrile-methacrylate copolymer (pp-methacrylate), polyvinyl acetate (polyacrylonitrile-methacrylate copolymer (PTFE), polyvinyl acetate (polyacrylonitrile-methacrylate copolymer (pp-acrylonitrile), polyvinyl acetate (polyacrylonitrile), polyvinyl acetate (PTFE), polyvinyl acetate (polyacrylonitrile (PTFE), polyvinyl acetate (poly (m-methacrylate), polyvinyl acetate (poly (m-methacrylate), poly (acrylonitrile-methacrylate), poly (acrylonitrile copolymer (m-methacrylate), poly (acrylonitrile copolymer (acrylonitrile-methacrylate), poly (acrylonitrile copolymer (acrylonitrile-methacrylate), poly (acrylonitrile copolymer (p-methacrylate), poly (acrylonitrile copolymer (acrylonitrile-methacrylate), poly (acrylonitrile copolymer (acrylonitrile-methacrylate), poly (, Polyimide (PI), Styrene Butadiene Rubber (SBR), polyethylene oxide (PEO), polypropylene oxide (PPO), poly (N-vinylacetamide) (PNVA), or poly (N-vinylformamide) (PNVF), but is not limited thereto. The above-mentioned binders may be used alone or in combination of two or more.
Suitable inorganic particles are not particularly limited, and those known to be suitable for use in the field of separator films, for example, fine particles having a dielectric constant of not less than 5, can be used. In one embodiment of the present invention, the particle size of the inorganic particles may be between 0.01 micrometers (μm) and 10 micrometers (μm). Suitable inorganic particles may be, for example, barium titanate (BaTiO3), lead zirconate titanate (Pb (Zr, Ti) O3, PZT), lead lanthanum zirconate titanate (Pb1-xLaxZr1-Y (ZrTiyO3), PLZT), lead magnesium niobate-lead titanate (Pb (Mg3, Nb2/3) O3-PbTiO3, PMN-PT), hafnium dioxide (HfO2), lithium titanate (SrTiO2), tin dioxide (SnO2), cerium dioxide (CeO2), magnesium oxide (MgO), magnesium hydroxide (Mg (oh)2), nickel oxide (NiO), calcium oxide (CaO), zinc oxide (ZnO), zirconium dioxide (ZrO2), silicon dioxide (SiO2), yttrium oxide (Y2O3), aluminum oxide (Al2O3), aluminum oxyhydroxide (alo (oh), silicon carbide (SiC), or titanium dioxide (TiO2), but are not limited thereto. The inorganic particles may be used alone or in combination of two or more.
In an embodiment of the manufacturing method of the present invention, the heat-resistant coating paste may further include a solvent to facilitate coating. Suitable solvents may be, for example, water, acetone, N-methylpyrrolidone (NMP), Dimethylacetamide (DMAC) or Dimethylsulfoxide (DMSO), but are not limited thereto. The aforementioned solvents may be used alone or in combination of two or more.
In an embodiment of the manufacturing method of the present invention, the heat-resistant coating slurry may optionally further include a dispersant, a wetting agent, or a surfactant, but is not limited thereto.
In an embodiment of the manufacturing method of the present invention, the coating method may be, for example, gravure coating (gravurrecoating), Slot-Die coating (Slot-Die coating), Roll coating (Roll coating), Wire-Bar coating (Wire-Bar coating), Blade coating (Blade coating), Extrusion coating (Extrusion coating), Dip coating (Dip coating), Spin coating, or the like (Spin coating), or slide coating (Slot-slide coating), but is not limited thereto.
In one embodiment of the manufacturing method of the present invention, the extension process may include one or more extension steps and optionally one or more retraction processes according to product requirements. The extension process may be performed in a single step or in multiple steps, or may be performed at different temperatures. The multi-step extension process may extend the substrate in the same direction or extend in different directions without particular limitation. The retracting process may be performed along with the extending step, or may be performed after the extending step/process is completed, without particular limitation.
In an embodiment of the manufacturing method of the present invention, the extending process includes a first extending process extending along a first direction. The first extension process may preferably include a cold extension process and a hot extension process.
In an embodiment of the manufacturing method of the present invention, the draw ratio of the cold drawing process may be between 5% and 60%, and preferably between 10% and 50%. The extension temperature of the cold extension process may be between 5 ℃ and 50 ℃, and preferably between 10 ℃ and 40 ℃.
In an embodiment of the manufacturing method of the present invention, the draw ratio of the thermal stretching process may be between 80% and 400%, and preferably between 100% and 300%. In a preferred embodiment of the present invention, the extension temperature of the thermal extension process may be between 80 ℃ and 160 ℃, and preferably between 100 ℃ and 150 ℃.
In an embodiment of the manufacturing method of the present invention, a first retracting process for retracting the substrate along the first direction may be optionally performed after the first extending process to adjust the physical properties of the isolation film and the coverage rate of the heat-resistant layer. The retraction magnification of the first retraction process may be between 0.1% and 30%, and preferably between 10% and 25%.
In another embodiment of the manufacturing method of the present invention, after the first stretching process, a second stretching process for stretching the substrate along a second direction may be optionally performed to adjust the physical properties of the isolation film, such as reducing the internal resistance, increasing the tensile strength, increasing the porosity or air permeability, or reducing the impedance by reducing the tortuosity of the pore diameter. Wherein the second direction may be perpendicular to the first direction. The extension temperature of the second extension process may be between 110 ℃ and 135 ℃, and is preferably between 115 ℃ and 130 ℃. The second extension process has an extension ratio of 10% to 150%, preferably 20% to 100%.
In another embodiment of the manufacturing method of the present invention, the second extending process may be optionally accompanied by a second retracting process for retracting the substrate along the first direction. The retraction magnification of the second retraction process may be between 5% and 50%, and preferably between 10% and 40%.
The following examples are intended to further illustrate the invention, but the invention is not limited thereto.
Examples
Example 1
50 g of alumina (Al2O3) particles (AHP 200, d50 of about 0.6 μm, available from light metals of Japan) were added to 100 g of an aqueous solution of a polyacrylamide dispersant having a concentration of 0.5%, and stirred to obtain an aqueous alumina dispersion having a concentration of 50%. Next, 5 g of water-soluble polyacrylate (BM-2000M, available from ZEON, japan) and 1 g of silicone surfactant (BYK-349, available from BYK-Chemie GmbH, germany) were added as wetting agents to the foregoing alumina dispersion aqueous solution to form a heat-resistant coating paste. Coating the heat-resistant coating slurry on a nonporous PP/PE/PP three-layer precursor substrate with the thickness of 21 micrometers (mum), performing a cold extension process (the extension ratio is 45 percent and the extension temperature is 25 ℃) on the nonporous PP/PE/PP three-layer precursor substrate coated with the coating along a first direction, performing a hot extension process (the extension ratio is 150 percent and the extension temperature is 128 ℃) along the first direction, and retracting the film by 30 percent to obtain the porous isolating membrane with the heat-resistant layer.
The surface of the separator was observed by a Scanning Electron Microscope (SEM). The surface view of the SEM at 200 magnifications is shown in FIG. 1, and the surface view of the SEM at 4,500 magnifications is shown in FIG. 2.
Example 2
A porous separator having a heat resistant layer was prepared in the same manner as in example 1, except that the elongation at the cold stretching process was changed to 30%, the elongation at the hot stretching process was changed to 140%, and the film was retracted by 15% after the hot stretching process.
The surface and cross section of the separator were observed by a Scanning Electron Microscope (SEM). The surface view of the SEM at 1,000 magnification is shown in FIG. 3, the surface view of the SEM at 4,500 magnification is shown in FIG. 4, and the cross-sectional view of the SEM at 2,000 magnification is shown in FIG. 5.
Example 3
A porous separator having a heat resistant layer was prepared in the same manner as in example 1, except that the elongation in the cold stretching process was changed to 30%, the elongation in the hot stretching process was changed to 150%, and the film was retracted by 11% after the hot stretching process.
The surface of the separator was observed by a Scanning Electron Microscope (SEM). The surface view of the SEM at 200 magnification is shown in FIG. 6, and the surface view of the SEM at 600 magnification is shown in FIG. 7.
Example 4
A porous separator having a heat resistant layer was prepared in the same manner as in example 1, except that the elongation at the cold stretching process was changed to 30%, the elongation at the hot stretching process was changed to 170%, and the film was retracted by 10% after the hot stretching process.
The surface of the separator was observed by a Scanning Electron Microscope (SEM). The surface view of the SEM at 200 magnifications is shown in FIG. 8, and the surface view of the SEM at 1,000 magnifications is shown in FIG. 9.
Example 5
The heat-resistant coating slurry prepared in example 1 was coated on a nonporous PP/PE/PP three-layer precursor substrate having a thickness of 21 micrometers (μm), and then the nonporous PP/PE/PP three-layer precursor substrate coated with the coating was subjected to a cold stretching process (stretching ratio of 30% and stretching temperature of 25 ℃) along a first direction, and then to a hot stretching process (stretching ratio of 130% and stretching temperature of 125 ℃) along the first direction, and after the substrate was retracted 10% along the first direction, finally to a hot stretching process (stretching ratio of 50%, stretching temperature of 130 ℃ and retraction of 30 ℃ along the first direction) along a second direction perpendicular to the first direction, thereby obtaining a porous separator having a heat-resistant layer.
The surface of the separator was observed by a Scanning Electron Microscope (SEM). The surface view of SEM at 200 magnification is shown in FIG. 10, and the surface view of SEM at 1,000 magnification is shown in FIG. 11.
Example 6
A porous separator having a heat-resistant layer was obtained in the same manner as in example 5, except that the draw ratio of the thermal stretching process performed in the second direction was changed to 20% with 10% retraction in the first direction.
The surface of the separator was observed by a Scanning Electron Microscope (SEM). The surface view of SEM at 200 magnification is shown in FIG. 12, and the surface view of SEM at 1,000 magnification is shown in FIG. 13.
Comparative example 1
The embodiment of comparative example 1 is the same as example 1, except that the non-porous PP/PE/PP three-layer precursor substrate of comparative example 1 is not coated with the heat-resistant coating slurry.
Comparative example 2
After a cold stretching process (the stretching ratio is 30% and the stretching temperature is 25 ℃) is carried out on a nonporous PP/PE/PP three-layer precursor substrate with the thickness of 21 micrometers along a first direction, a hot stretching process (the stretching ratio is 130% and the stretching temperature is 125 ℃) is carried out along the first direction, and finally, the film is retracted by 10% along the first direction, so that a porous PP/PE/PP three-layer film with the thickness of 18 micrometers (mum) is prepared. The heat-resistant coating slurry prepared in example 1 was coated on the porous PP/PE/PP three-layer film, and then the porous PP/PE/PP three-layer film with the heat-resistant coating was placed in an oven at 85 ℃ for 2 minutes to prepare a porous separator in which the heat-resistant layer completely covered the substrate.
The surface of the separator was observed by a Scanning Electron Microscope (SEM). The surface view of SEM at 1,000 magnification is shown in FIG. 14.
The physical properties of the separators of examples 1 to 6 and comparative examples 1 to 2 were measured in the following manner.
Heat resistance layer coverage
The surface of the isolating membrane is shot by an electron microscope (Hitachi S-4300), and the coverage rate of the heat-resistant layer is calculated by image analysis software according to the shot picture.
Thickness of isolation film
The test was carried out using a film thickness meter (VL-50-B, available from Mitutoyo, Japan) in accordance with the test standard GB/T6672-2001. The test was carried out using a flat probe having a diameter of 3mm and a probe load of 0.01N.
Air permeability test (Gurley number)
According to JIS P8117-.
AC impedance (AC impedance)
The separators obtained in examples and comparative examples were cut into a circular shape having a diameter of 24mm, and then immersed in a standard electrolyte (LiPF 6 solution having a concentration of 1M, a solvent weight ratio EC/DMC/EMC of 1/1/1) for 12 hours to allow the electrolyte to completely permeate the separator, and then the separator was placed between two electrodes, and ac impedance was measured at a frequency of 1000 to 200,000.
Puncture strength (punch strength)
The puncture strength was measured with a tensile machine (MSG-5, available from Kato Tech, Japan) using a round-headed stainless steel needle with a needle diameter of 1mm and an R angle of 0.5mm at a test speed of 100. + -. 10mm/min to puncture a sample to be tested, and the maximum force (gf) required to puncture the separator to be tested was recorded.
Moisture content (moisture)
The water content of the isolation film was measured by placing the sample in a Karl Fischer at a machine temperature of 150 ℃ for 300 seconds using JIS K0068-2001 test standards.
Heat Shrinkage (Shrinkage)
The separator was cut into a sample of 10X 10cm, and the initial length M0 in the Machine Direction (MD) was marked at the center position of the sample before the test. Clamping the sample in two pieces of A4 paper after marking, putting the sample in an oven, heating the sample at 130 ℃ for 1 hour, putting the sample in the same environment as a measuring instrument for 30 minutes after heating, and measuring the longitudinal (MD) length M1 of the center of the sample; the Machine Direction (MD) heat Shrinkage (SMD) calculation formula is as follows: SMD ═ M0-M1)/M0 × 100%.
The test results of the above physical properties are shown in tables 1 and 2 below.
TABLE 1 physical Properties of examples 1 to 4 and comparative examples 1 to 2
As is apparent from the characteristic expressions shown in table 1, the porous separators having a heat-resistant layer according to examples 1 to 4 of the present invention have better heat-resistant properties, puncture strength, and puncture strength than the separators having no heat-resistant layer according to comparative example 1, but maintain similar air permeability and ac impedance. In contrast to the separator of comparative example 2 in which the heat-resistant layer completely covers the substrate, the separators of examples 1 to 4 of the present invention have lower water content, better air permeability, and better ac impedance.
Table 2 physical properties of examples 5-6
| Example 5 | Example 6 | |
| Heat-resistant layer coverage (%) | 60 | 70 |
| Total thickness (mum) | 19.4 | 20.1 |
| Thickness of Heat-resistant layer (μm) | 4 | 4 |
| Gurley air permeability (sec.) | 103 | 115 |
| AC impedance (ohm cm)2) | 0.68 | 0.77 |
| Puncture Strength (gf) | 286 | 302 |
| Water content (ppm) | 213 | 229 |
| MD Heat shrinkage (%) | 17 | 30 |
As can be seen from the characteristic expressions shown in table 2, the heat-resistant layer separators obtained by the biaxial stretching processes of examples 5 and 6 according to the present invention have better air permeability and lower ac impedance, and still have better heat resistance than the heat-resistant layer separator of comparative example 1, while maintaining appropriate water content and puncture strength, which are required as a battery separator.
In summary, the present invention provides a separator and a method for manufacturing the same, wherein the separator comprises a substrate having a porous structure and a heat-resistant layer disposed on one or both surfaces of the substrate having the porous structure. The heat-resistant layer comprises a binder and a plurality of inorganic particles, and the coverage rate of the heat-resistant layer on the substrate is between 10% and 90%. The manufacturing method of the isolating membrane of the invention is to coat the heat-resistant coating slurry containing the adhesive and the inorganic particles on the nonporous precursor substrate, and then carry out the extension process to form the substrate with the porous structure and the heat-resistant layer. The invention can avoid the inorganic particles in the coating slurry from blocking the micropores in the base material, so that the prepared isolating membrane has good air permeability and lower alternating current impedance. Meanwhile, the heat-resistant layer can improve the heat resistance and the puncture strength of the isolating membrane and can also maintain lower water content.
While the invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the claims.
Claims (20)
1. A separator, comprising:
a substrate having a porous structure; and
a heat-resistant layer disposed on one or both side surfaces of the substrate, the heat-resistant layer comprising:
an adhesive; and
a plurality of inorganic particles;
wherein, the coverage rate of the heat-resistant layer on the base material is between 10% and 90%.
2. The separator of claim 1, wherein: the heat-resistant layer forms a continuous network structure or a sea-island structure on the base material.
3. The separator of claim 1, wherein: the thickness of the heat-resistant layer is between 0.01 and 20 microns.
4. The separator of claim 1, wherein: the heat-resistant layer includes 1 to 20 parts by weight of the binder and 80 to 99 parts by weight of the plurality of inorganic particles.
5. The separator of claim 1, wherein: the particle size of the inorganic particles is between 0.01 and 10 microns.
6. The separator of claim 1, wherein: the heat-resistant layer is formed by coating a heat-resistant coating slurry on a non-porous precursor substrate and then performing an extension process.
7. The separator of claim 1, wherein: the binder is at least one selected from the group consisting of polyvinyl chloride, polyvinyl fluoride, polytetrafluoroethylene, polyvinylidene fluoride-tetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene copolymer, polyvinylidene fluoride-tetrafluoroethylene chloride, poly (meth) acrylate, polyacrylonitrile, polyvinyl acetate, polyethylene-vinyl acetate copolymer, polyimide, styrene butadiene rubber, polyethylene oxide, polypropylene oxide, poly (N-ethylene acetamide), and poly (N-vinyl formamide), or a combination thereof.
8. The separator of claim 1, wherein: the inorganic particles are at least one selected from the group consisting of barium titanate, lead zirconate titanate, lead lanthanum zirconate titanate, lead magnesium niobate-lead titanate, hafnium dioxide, lithium titanate, tin dioxide, cerium dioxide, magnesium oxide, magnesium hydroxide, nickel oxide, calcium oxide, zinc oxide, zirconium dioxide, silicon dioxide, yttrium oxide, aluminum oxyhydroxide, silicon carbide and titanium dioxide, or a combination thereof.
9. A method for manufacturing a separator, comprising the steps of:
providing a nonporous precursor substrate;
coating a heat-resistant coating slurry on one or both surfaces of the nonporous precursor substrate to form a heat-resistant coating, wherein the heat-resistant coating slurry comprises a binder and a plurality of inorganic particles; and
carrying out an extension process on the nonporous precursor substrate with the heat-resistant coating to prepare an isolating membrane with a heat-resistant layer and a porous structure substrate;
wherein the coverage rate of the heat-resistant layer on the base material is between 10% and 90%.
10. The manufacturing method according to claim 9, characterized in that: the heat-resistant coating paste includes 1 to 20 parts by weight of the binder and 80 to 99 parts by weight of the plurality of inorganic particles.
11. The manufacturing method according to claim 9, characterized in that: the heat-resistant coating paste further includes a solvent selected from at least one of the group consisting of water, acetone, N-methylpyrrolidone, dimethylacetamide, and dimethylsulfoxide, or a combination thereof.
12. The manufacturing method according to claim 9, characterized in that: the particle size of the inorganic particles is between 0.01 and 10 microns.
13. The manufacturing method according to claim 9, characterized in that: the material of the nonporous precursor substrate comprises polyethylene, polypropylene, polyester, or polyamide.
14. The manufacturing method according to claim 9, characterized in that: the extension process includes a first extension process extending along a first direction.
15. The manufacturing method according to claim 14, characterized in that: the first extension process includes a cold extension process and/or a hot extension process.
16. The manufacturing method according to claim 15, characterized in that: the extension temperature of the cold extension process is between 5 ℃ and 50 ℃, and the extension rate of the cold extension process is between 5 percent and 60 percent; or,
the extension temperature of the thermal extension process is between 80 ℃ and 160 ℃, and the extension ratio of the thermal extension process is between 80% and 400%.
17. The manufacturing method according to claim 14, characterized in that: the extension process further comprises a first retraction process retracting along the first direction, and the retraction rate of the first retraction process is between 0.1% and 30%.
18. The manufacturing method according to claim 14, characterized in that: the extension process further includes a second extension process extending along a second direction, and the second direction is perpendicular to the first direction.
19. The manufacturing method according to claim 18, characterized in that: the second extension process has an extension temperature between 110 ℃ and 135 ℃ and an extension ratio between 10% and 150%.
20. The manufacturing method according to claim 19, characterized in that: the extension process further comprises a second retraction process retracting along the first direction, and the retraction rate of the second retraction process is between 5% and 50%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2020102364953 | 2020-03-30 | ||
| CN202010236495 | 2020-03-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111900311A true CN111900311A (en) | 2020-11-06 |
Family
ID=73230313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010811439.8A Pending CN111900311A (en) | 2020-03-30 | 2020-08-13 | Isolating membrane and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111900311A (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102983300A (en) * | 2011-09-05 | 2013-03-20 | 索尼公司 | Separator and nonaqueous electrolyte battery |
| CN103956447A (en) * | 2014-04-23 | 2014-07-30 | 明基材料有限公司 | Porous isolating membrane and manufacturing method thereof |
| CN104218205A (en) * | 2014-07-31 | 2014-12-17 | 明基材料有限公司 | Heat-resistant porous isolating membrane and manufacturing method thereof |
| KR20150035168A (en) * | 2013-09-27 | 2015-04-06 | 제일모직주식회사 | Separator containing coating layer and battery using the separator |
| CN106104850A (en) * | 2014-09-26 | 2016-11-09 | 旭化成株式会社 | Electrical storage device separator |
| CN108123089A (en) * | 2017-12-12 | 2018-06-05 | 上海恩捷新材料科技股份有限公司 | Isolation film and electrochemical appliance |
| CN108565379A (en) * | 2018-03-19 | 2018-09-21 | 上海恩捷新材料科技股份有限公司 | A kind of lithium battery diaphragm and preparation method thereof |
| CN109004164A (en) * | 2018-07-26 | 2018-12-14 | 中航锂电技术研究院有限公司 | A kind of lithium-ion-power cell pressure sensitive composite diaphragm |
| CN110600661A (en) * | 2019-08-19 | 2019-12-20 | 安徽理工大学 | Composite diaphragm with netted coating |
| CN210129544U (en) * | 2019-07-01 | 2020-03-06 | 中科(马鞍山)新材料科创园有限公司 | Lithium ion battery diaphragm with high stable structure |
-
2020
- 2020-08-13 CN CN202010811439.8A patent/CN111900311A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102983300A (en) * | 2011-09-05 | 2013-03-20 | 索尼公司 | Separator and nonaqueous electrolyte battery |
| KR20150035168A (en) * | 2013-09-27 | 2015-04-06 | 제일모직주식회사 | Separator containing coating layer and battery using the separator |
| CN103956447A (en) * | 2014-04-23 | 2014-07-30 | 明基材料有限公司 | Porous isolating membrane and manufacturing method thereof |
| CN104218205A (en) * | 2014-07-31 | 2014-12-17 | 明基材料有限公司 | Heat-resistant porous isolating membrane and manufacturing method thereof |
| CN106104850A (en) * | 2014-09-26 | 2016-11-09 | 旭化成株式会社 | Electrical storage device separator |
| CN108123089A (en) * | 2017-12-12 | 2018-06-05 | 上海恩捷新材料科技股份有限公司 | Isolation film and electrochemical appliance |
| CN108565379A (en) * | 2018-03-19 | 2018-09-21 | 上海恩捷新材料科技股份有限公司 | A kind of lithium battery diaphragm and preparation method thereof |
| CN109004164A (en) * | 2018-07-26 | 2018-12-14 | 中航锂电技术研究院有限公司 | A kind of lithium-ion-power cell pressure sensitive composite diaphragm |
| CN210129544U (en) * | 2019-07-01 | 2020-03-06 | 中科(马鞍山)新材料科创园有限公司 | Lithium ion battery diaphragm with high stable structure |
| CN110600661A (en) * | 2019-08-19 | 2019-12-20 | 安徽理工大学 | Composite diaphragm with netted coating |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR102586597B1 (en) | Improved coatings, coated separators, batteries, and related methods | |
| KR101840616B1 (en) | Porous film and multilayer porous film | |
| KR20200108474A (en) | Improved coated separator, lithium battery, and related method | |
| US20240254303A1 (en) | Base films for impregnation, improved impregnated products, and related methods | |
| TW201530862A (en) | Separator for electrochemical device and electrochemical device | |
| KR20200012918A (en) | New or Improved Microporous Membrane, Cell Separator, Coated Separator, Cell, and Related Methods | |
| JP2018162438A (en) | Polyolefin microporous film and method for producing polyolefin microporous film | |
| CN116169431A (en) | Separator for nonaqueous secondary battery and nonaqueous secondary battery | |
| KR20150068711A (en) | Separator for electrochemical device with improved curling/crack condition and a method of making the same | |
| TWI764214B (en) | Separator and method for manufacturing thereof | |
| CN111463391A (en) | Improved coated separator, lithium battery and related methods | |
| US11616273B2 (en) | Method for manufacturing a separator | |
| CN111900311A (en) | Isolating membrane and manufacturing method thereof | |
| KR20160041493A (en) | A method of manufacturing separator for electrochemical device and separator for electrochemical device manufactured thereby | |
| JP7525686B2 (en) | Polyolefin microporous membrane | |
| JP2023161496A (en) | Polyolefin microporous film |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20201106 |