JP2009205956A - Nonaqueous electrolyte battery separator, manufacturing method thereof, and nonaqueous electrolyte secondary battery using the separator - Google Patents
Nonaqueous electrolyte battery separator, manufacturing method thereof, and nonaqueous electrolyte secondary battery using the separator Download PDFInfo
- Publication number
- JP2009205956A JP2009205956A JP2008047747A JP2008047747A JP2009205956A JP 2009205956 A JP2009205956 A JP 2009205956A JP 2008047747 A JP2008047747 A JP 2008047747A JP 2008047747 A JP2008047747 A JP 2008047747A JP 2009205956 A JP2009205956 A JP 2009205956A
- Authority
- JP
- Japan
- Prior art keywords
- heat
- electrolyte battery
- battery separator
- molecular weight
- nonaqueous electrolyte
- 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.)
- Granted
Links
- 239000011255 nonaqueous electrolyte Substances 0.000 title claims abstract description 77
- 238000004519 manufacturing process Methods 0.000 title claims description 23
- 229920000642 polymer Polymers 0.000 claims abstract description 62
- 238000009826 distribution Methods 0.000 claims abstract description 31
- 238000000576 coating method Methods 0.000 claims abstract description 28
- 239000000463 material Substances 0.000 claims abstract description 27
- 239000011148 porous material Substances 0.000 claims abstract description 13
- -1 aromatic dicarboxylic acid halide Chemical class 0.000 claims description 53
- 229920003235 aromatic polyamide Polymers 0.000 claims description 40
- 239000004760 aramid Substances 0.000 claims description 39
- 239000000758 substrate Substances 0.000 claims description 29
- 239000000243 solution Substances 0.000 claims description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 25
- 239000011248 coating agent Substances 0.000 claims description 23
- 239000007788 liquid Substances 0.000 claims description 22
- 239000003960 organic solvent Substances 0.000 claims description 22
- 239000011256 inorganic filler Substances 0.000 claims description 21
- 229910003475 inorganic filler Inorganic materials 0.000 claims description 21
- 150000004984 aromatic diamines Chemical class 0.000 claims description 17
- 229920000098 polyolefin Polymers 0.000 claims description 15
- 238000005345 coagulation Methods 0.000 claims description 14
- 230000015271 coagulation Effects 0.000 claims description 14
- 239000002904 solvent Substances 0.000 claims description 14
- 229920005992 thermoplastic resin Polymers 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 10
- 239000004952 Polyamide Substances 0.000 claims description 9
- 229920002647 polyamide Polymers 0.000 claims description 9
- 230000001112 coagulating effect Effects 0.000 claims description 8
- 229910000000 metal hydroxide Inorganic materials 0.000 claims description 8
- 150000004692 metal hydroxides Chemical class 0.000 claims description 8
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 7
- 229910001416 lithium ion Inorganic materials 0.000 claims description 7
- 238000005406 washing Methods 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 6
- 239000002798 polar solvent Substances 0.000 claims description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 4
- 229910052744 lithium Inorganic materials 0.000 claims description 4
- 239000011800 void material Substances 0.000 claims description 4
- 239000004695 Polyether sulfone Substances 0.000 claims description 3
- 239000004697 Polyetherimide Substances 0.000 claims description 3
- 239000004642 Polyimide Substances 0.000 claims description 3
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 239000006185 dispersion Substances 0.000 claims description 3
- 229920001643 poly(ether ketone) Polymers 0.000 claims description 3
- 229920002492 poly(sulfone) Polymers 0.000 claims description 3
- 229920006393 polyether sulfone Polymers 0.000 claims description 3
- 229920001601 polyetherimide Polymers 0.000 claims description 3
- 229920001721 polyimide Polymers 0.000 claims description 3
- 230000000379 polymerizing effect Effects 0.000 claims description 3
- 239000011347 resin Substances 0.000 abstract 1
- 229920005989 resin Polymers 0.000 abstract 1
- 229920001187 thermosetting polymer Polymers 0.000 abstract 1
- 238000000034 method Methods 0.000 description 29
- 239000012982 microporous membrane Substances 0.000 description 27
- 239000004698 Polyethylene Substances 0.000 description 24
- 229920000573 polyethylene Polymers 0.000 description 23
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 10
- 239000012528 membrane Substances 0.000 description 9
- 238000010528 free radical solution polymerization reaction Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 6
- NNBZCPXTIHJBJL-UHFFFAOYSA-N decalin Chemical compound C1CCCC2CCCCC21 NNBZCPXTIHJBJL-UHFFFAOYSA-N 0.000 description 6
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 5
- 125000003118 aryl group Chemical group 0.000 description 5
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 4
- 238000012695 Interfacial polymerization Methods 0.000 description 4
- 230000010220 ion permeability Effects 0.000 description 4
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 4
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 description 3
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 3
- LCZVSXRMYJUNFX-UHFFFAOYSA-N 2-[2-(2-hydroxypropoxy)propoxy]propan-1-ol Chemical compound CC(O)COC(C)COC(C)CO LCZVSXRMYJUNFX-UHFFFAOYSA-N 0.000 description 3
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 3
- 239000000920 calcium hydroxide Substances 0.000 description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 239000003063 flame retardant Substances 0.000 description 3
- 229940057995 liquid paraffin Drugs 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- PXXNTAGJWPJAGM-UHFFFAOYSA-N vertaline Natural products C1C2C=3C=C(OC)C(OC)=CC=3OC(C=C3)=CC=C3CCC(=O)OC1CC1N2CCCC1 PXXNTAGJWPJAGM-UHFFFAOYSA-N 0.000 description 3
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 2
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000003125 aqueous solvent Substances 0.000 description 2
- FDQSRULYDNDXQB-UHFFFAOYSA-N benzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1 FDQSRULYDNDXQB-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000006255 coating slurry Substances 0.000 description 2
- 239000002482 conductive additive Substances 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical class 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000012046 mixed solvent Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000007774 positive electrode material Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 125000001424 substituent group Chemical group 0.000 description 2
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 1
- ZKTONHQBQNLNPS-UHFFFAOYSA-N 1-chlorocyclohexa-3,5-diene-1,3-dicarboxylic acid Chemical compound OC(=O)C1=CC=CC(Cl)(C(O)=O)C1 ZKTONHQBQNLNPS-UHFFFAOYSA-N 0.000 description 1
- IVORCBKUUYGUOL-UHFFFAOYSA-N 1-ethynyl-2,4-dimethoxybenzene Chemical compound COC1=CC=C(C#C)C(OC)=C1 IVORCBKUUYGUOL-UHFFFAOYSA-N 0.000 description 1
- OCZKRTWSBSEECY-UHFFFAOYSA-N 1-methoxycyclohexa-3,5-diene-1,3-dicarbonyl chloride Chemical compound COC1(C(Cl)=O)CC(C(Cl)=O)=CC=C1 OCZKRTWSBSEECY-UHFFFAOYSA-N 0.000 description 1
- RLYCRLGLCUXUPO-UHFFFAOYSA-N 2,6-diaminotoluene Chemical compound CC1=C(N)C=CC=C1N RLYCRLGLCUXUPO-UHFFFAOYSA-N 0.000 description 1
- LKGQTURGJNTDLR-UHFFFAOYSA-N 2-chlorobenzene-1,3-diamine Chemical compound NC1=CC=CC(N)=C1Cl LKGQTURGJNTDLR-UHFFFAOYSA-N 0.000 description 1
- ZBMISJGHVWNWTE-UHFFFAOYSA-N 3-(4-aminophenoxy)aniline Chemical compound C1=CC(N)=CC=C1OC1=CC=CC(N)=C1 ZBMISJGHVWNWTE-UHFFFAOYSA-N 0.000 description 1
- ZMPZWXKBGSQATE-UHFFFAOYSA-N 3-(4-aminophenyl)sulfonylaniline Chemical compound C1=CC(N)=CC=C1S(=O)(=O)C1=CC=CC(N)=C1 ZMPZWXKBGSQATE-UHFFFAOYSA-N 0.000 description 1
- ZWUBBMDHSZDNTA-UHFFFAOYSA-N 4-Chloro-meta-phenylenediamine Chemical compound NC1=CC=C(Cl)C(N)=C1 ZWUBBMDHSZDNTA-UHFFFAOYSA-N 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910013684 LiClO 4 Inorganic materials 0.000 description 1
- 229910012735 LiCo1/3Ni1/3Mn1/3O2 Inorganic materials 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910010707 LiFePO 4 Inorganic materials 0.000 description 1
- 229910015645 LiMn Inorganic materials 0.000 description 1
- 229910016087 LiMn0.5Ni0.5O2 Inorganic materials 0.000 description 1
- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 239000006087 Silane Coupling Agent Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 description 1
- WETWJCDKMRHUPV-UHFFFAOYSA-N acetyl chloride Chemical compound CC(Cl)=O WETWJCDKMRHUPV-UHFFFAOYSA-N 0.000 description 1
- 239000012346 acetyl chloride Substances 0.000 description 1
- 239000000159 acid neutralizing agent Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- YAZXITQPRUBWGP-UHFFFAOYSA-N benzene-1,3-dicarbonyl bromide Chemical compound BrC(=O)C1=CC=CC(C(Br)=O)=C1 YAZXITQPRUBWGP-UHFFFAOYSA-N 0.000 description 1
- PASDCCFISLVPSO-UHFFFAOYSA-N benzoyl chloride Chemical compound ClC(=O)C1=CC=CC=C1 PASDCCFISLVPSO-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- VQWFNAGFNGABOH-UHFFFAOYSA-K chromium(iii) hydroxide Chemical compound [OH-].[OH-].[OH-].[Cr+3] VQWFNAGFNGABOH-UHFFFAOYSA-K 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000004035 construction material Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 150000004985 diamines Chemical class 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000009998 heat setting Methods 0.000 description 1
- 239000012210 heat-resistant fiber Substances 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000039 hydrogen halide Inorganic materials 0.000 description 1
- 239000012433 hydrogen halide Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- QQVIHTHCMHWDBS-UHFFFAOYSA-N perisophthalic acid Natural products OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
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- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- GPRLSGONYQIRFK-MNYXATJNSA-N triton Chemical compound [3H+] GPRLSGONYQIRFK-MNYXATJNSA-N 0.000 description 1
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 description 1
Images
Classifications
-
- 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
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- Cell Separators (AREA)
Abstract
Description
本発明は、機械的特性と安全性が向上した非水電解質電池セパレータとその製造方法、並びに、それを用いた非水電解質二次電池に関するものである。 The present invention relates to a nonaqueous electrolyte battery separator with improved mechanical properties and safety, a method for producing the same, and a nonaqueous electrolyte secondary battery using the same.
非水電解質電池、特に、リチウムイオン二次電池に代表される非水電解質二次電池は、高エネルギー密度であり、携帯電話・ノートパソコンといった携帯用電子機器の主電源として広範に普及している。このリチウムイオン二次電池は、更なる高エネルギー密度化が求められているが、安全性の確保が技術的な課題となっている。リチウムイオン二次電池の安全性確保においてセパレータの役割は重要であり、シャットダウン機能を有するという観点から、現状ではポリオレフィン、特にポリエチレン微多孔膜が用いられている。ここで、シャットダウン機能とは、電池の温度が上昇したときに、微多孔膜の孔が閉塞し電流を遮断する機能のことを言い、電池の熱暴走を食い止める働きがある。 Nonaqueous electrolyte batteries, particularly nonaqueous electrolyte secondary batteries represented by lithium ion secondary batteries, have high energy density and are widely used as the main power source for portable electronic devices such as mobile phones and laptop computers. . This lithium ion secondary battery is required to have a higher energy density, but ensuring safety is a technical issue. The role of the separator is important in ensuring the safety of the lithium ion secondary battery, and from the viewpoint of having a shutdown function, polyolefins, particularly polyethylene microporous membranes are currently used. Here, the shutdown function refers to a function of blocking pores in the microporous membrane when the temperature of the battery rises, and blocking the current, and has a function of preventing thermal runaway of the battery.
一方、リチウムイオン二次電池は、年々高エネルギー密度化がなされており、安全性確保のためシャットダウン機能に加えて耐熱性も要求されてきている。しかしながら、シャットダウン機能は、ポリエチレンの溶融による孔の閉塞をその作動原理としているので耐熱性と相反するものである。このため、シャットダウン機能が作動した後、さらに電池がシャットダウン機能が作動する温度以上に曝され続けることで、セパレータの溶融(いわゆるメルトダウン)が進行してしまう場合がある。このメルトダウンの結果、電池内部で短絡が生じ、これに伴って大きな熱が発生してしまい、電池は発煙・発火・爆発といった危険に曝されることになる。このため、セパレータにはシャットダウン機能に加えて、シャットダウン機能が作動する温度近傍でメルトダウンが生じない程度の十分な耐熱性が要求される。 On the other hand, lithium ion secondary batteries have been increased in energy density year by year, and heat resistance has been required in addition to a shutdown function to ensure safety. However, the shutdown function is contrary to heat resistance because the operating principle is to close the hole by melting polyethylene. For this reason, after the shutdown function is activated, the battery may continue to be exposed to a temperature higher than the temperature at which the shutdown function is activated, whereby the separator may be melted (so-called meltdown). As a result of this meltdown, a short circuit occurs inside the battery, and as a result, a large amount of heat is generated, and the battery is exposed to dangers such as smoke, ignition, and explosion. For this reason, in addition to the shutdown function, the separator is required to have sufficient heat resistance that does not cause meltdown in the vicinity of the temperature at which the shutdown function operates.
この点において、従来、耐熱性とシャットダウン機能を両立させるために、ポリオレフィン微多孔膜の片面又は両面(表面と裏面)に耐熱性多孔質層を被覆させたり、耐熱性繊維からなる不織布を積層させるという技術が提案されている。例えば、ポリエチレン微多孔膜の片面又は両面に、湿式塗工法により芳香族アラミド等の耐熱性高分子からなる耐熱性多孔質層を積層した非水電解質電池セパレータが知られている(特許文献1〜4参照)。 In this regard, conventionally, in order to achieve both heat resistance and a shutdown function, one surface or both surfaces (front and back surfaces) of the polyolefin microporous film are coated with a heat resistant porous layer, or a nonwoven fabric made of heat resistant fibers is laminated. The technology is proposed. For example, a nonaqueous electrolyte battery separator is known in which a heat-resistant porous layer made of a heat-resistant polymer such as aromatic aramid is laminated on one side or both sides of a polyethylene microporous membrane by a wet coating method (Patent Documents 1 to 3). 4).
このような非水電解質電池セパレータは、ポリエチレンの融点近傍(140℃程度)でシャットダウン機能が作動すると共に、耐熱性多孔質層が十分な耐熱性を示すことにより200℃以上においてもメルトダウンが発生しないため、優れた耐熱性およびシャットダウン機能を発揮する。 Such a non-aqueous electrolyte battery separator operates with a shutdown function near the melting point of polyethylene (about 140 ° C), and the heat-resistant porous layer exhibits sufficient heat resistance, so that meltdown occurs even at 200 ° C or higher. Therefore, it exhibits excellent heat resistance and shutdown function.
ここで、湿式塗工法により、耐熱性高分子を溶解した塗工液をポリオレフィン微多孔膜上に塗工する場合は、塗工液がポリオレフィン微多孔膜表面の孔から内部に入り込んでしまい、目詰まりが発生しやすいという問題がある。このような場合、ポリオレフィン微多孔膜と耐熱性多孔質層との界面におけるイオン透過性が低下し、ひいては電池の膜抵抗が増加してしまうおそれがある。 Here, when the coating liquid in which the heat-resistant polymer is dissolved is applied onto the polyolefin microporous film by the wet coating method, the coating liquid enters the inside through the pores on the surface of the polyolefin microporous film, There is a problem that clogging is likely to occur. In such a case, the ion permeability at the interface between the polyolefin microporous membrane and the heat-resistant porous layer may be lowered, and the membrane resistance of the battery may be increased.
一方、セパレータは機械的強度が高いほど好ましく、このようなセパレータは電極と合わせて電池を製造する際に、破れたりしないので歩留まりが向上する。さらに、セパレータは機械的強度が高ければ電池の安全性も高まるので好ましい。従って、好ましい非水電解質電池セパレータを開発するに際しては、機械特性も考慮する必要がある。 On the other hand, the higher the mechanical strength of the separator, the better. Since such a separator is not torn when manufacturing a battery together with the electrode, the yield is improved. Furthermore, it is preferable that the separator has a high mechanical strength because the safety of the battery is increased. Therefore, when developing a preferred nonaqueous electrolyte battery separator, it is necessary to consider mechanical characteristics.
従って、本発明は、ポリオレフィンの微多孔膜等の基材の片面又は両面に、湿式塗工法にて、芳香族アラミド等の耐熱性高分子からなる耐熱性多孔質層を形成して非水電解質電池セパレータを得るに際し、塗工性を改良すると共に、機械特性、電池特性に優れた非水電解質電池セパレータを提供することを目的とする。 Therefore, the present invention provides a non-aqueous electrolyte by forming a heat-resistant porous layer made of a heat-resistant polymer such as aromatic aramid on one or both surfaces of a substrate such as a microporous membrane of polyolefin by a wet coating method. In obtaining a battery separator, an object is to provide a nonaqueous electrolyte battery separator having improved mechanical properties and battery characteristics while improving coating properties.
上記課題を解決するために、本発明は以下の構成を採用する。
(1) 主として熱可塑性樹脂にて形成され内部に空孔ないし空隙を有しシャットダウン機能を有する基材と、主として耐熱性高分子にて形成され前記基材の片面又は両面に積層された耐熱性多孔質層とを備えた非水電解質電池セパレータであって、前記耐熱性高分子の分子量分布Mw/Mnが、1<Mw/Mn<5であり、且つ、前記耐熱性高分子の重量平均分子量Mwが、8.0×103以上1.0×106以下であることを特徴とする非水電解質電池セパレータ。
(2) 前記耐熱性高分子は、分子量8.0×103以下の低分子量ポリマーの含有量が、1重量%未満のものであることを特徴とする上記(1)記載の非水電解質電池セパレータ。
(3) 前記非水電解質電池セパレータは、突刺強度が100〜2000gである
ことを特徴とする上記(1)又は(2)記載の非水電解質電池セパレータ。
(4) 前記耐熱性多孔質層が、重量分率で50重量%以上95重量%以下の無機フィラーを含むことを特徴とする上記(1)〜(3)のいずれかに記載の非水電解質電池セパレータ。
(5) 前記無機フィラーが、主として金属水酸化物からなることを特徴とする上記(4)記載の非水電解質電池セパレータ。
(6) 前記耐熱性高分子が、芳香族ポリアミド、ポリイミド、ポリエーテルスルホン、ポリスルホン、ポリエーテルケトン、ポリエーテルイミドからなる群から選ばれる1種又は2種以上であることを特徴とする上記(1)〜(5)のいずれかに記載の非水電解質電池セパレータ。
(7) 前記芳香族ポリアミドが、芳香族ジカルボン酸ハライドと芳香族ジアミンを、生成するポリアミドに対し良溶媒である有機極性溶媒中で重合させることにより製造されたものであることを特徴とする上記(6)記載の非水電解質電池セパレータ。
(8) 前記基材が、ポリオレフィンを主体とする熱可塑性樹脂からなる微多孔膜であることを特徴とする前記(1)〜(7)のいずれかに記載の非水電解質電池セパレータ。
(9) 前記非水電解質電池セパレータが、リチウムイオン二次電池用セパレータであることを特徴とする上記(1)〜(8)のいずれかに記載の非水電解質電池セパレータ。
(10) 主として熱可塑性樹脂にて形成され内部に空孔ないし空隙を有しシャットダウン機能を有する基材と、主として芳香族ポリアミドにて形成され前記基材の片面又は両面に積層された耐熱性多孔質層とを備えた上記(1)に記載の非水電解質電池セパレータの製造方法であって、(i)芳香族ジカルボン酸ハライドと芳香族ジアミンを、生成するポリアミドに対し良溶媒である有機溶媒中で反応せしめて、分子量分布Mw/Mnが1<Mw/Mn<5であり、且つ、重量平均分子量Mwが8.0×103以上1.0×106以下である芳香族ポリアミドを製造する工程と、(ii)得られた芳香族ポリアミドの水溶性有機溶剤溶液を、前記基材の片面又は両面に塗工する工程と、(iii)塗工された前記基材を水又は水と前記有機溶剤の混合液からなる凝固液中に浸漬して芳香族ポリアミドを凝固させる工程と、(iv)この凝固工程後の前記基材を水洗し乾燥する工程と、を実施することを特徴とする非水電解質電池セパレータの製造方法。
(11) 主として熱可塑性樹脂にて形成されシャットダウン機能を有する内部に空孔ないし空隙を有しシャットダウン機能を有する基材と、主としてメタ型芳香族ポリアミドにて形成され前記基材の片面又は両面に積層された耐熱性多孔質層とを備えた上記(1)に記載の非水電解質電池セパレータの製造方法であって、(i)メタ型芳香族ジカルボン酸ハライドとメタ型芳香族ジアミンを、生成するポリアミドに対し良溶媒でない有機溶媒中で反応せしめて溶液若しくは分散液を作り、これを酸受容剤の水溶液と接触させ反応を完結せしめて、分子量分布Mw/Mnが1<Mw/Mn<5であり、且つ、重量平均分子量Mwが8.0×103以上1.0×106以下であるメタ型芳香族ポリアミドを製造する工程と、(ii)得られたメタ型芳香族ポリアミドの水溶性有機溶剤溶液を、前記基材の片面又は両面に塗工する工程と、(iii)塗工された前記基材を、水又は水と前記有機溶剤の混合液からなる凝固液中に浸漬して、メタ型芳香族ポリアミドを凝固させる工程と、(iv)この凝固工程後の前記基材を水洗し乾燥する工程と、を実施することを特徴とする非水電解質電池セパレータの製造方法。
(12) リチウムのドープ・脱ドープにより起電力を得る非水電解質二次電池であって、上記(1)〜(9)のいずれかに記載の非水電解質電池セパレータを用いたことを特徴とする非水電解質二次電池。
In order to solve the above problems, the present invention employs the following configuration.
(1) A base material mainly formed of a thermoplastic resin and having a pore or void inside, and having a shutdown function, and a heat resistance mainly formed of a heat-resistant polymer and laminated on one or both sides of the base material A non-aqueous electrolyte battery separator comprising a porous layer, wherein the molecular weight distribution Mw / Mn of the heat-resistant polymer is 1 <Mw / Mn <5, and the weight-average molecular weight of the heat-resistant polymer A nonaqueous electrolyte battery separator, wherein Mw is 8.0 × 10 3 or more and 1.0 × 10 6 or less.
(2) The non-aqueous electrolyte battery according to (1), wherein the heat-resistant polymer has a content of a low molecular weight polymer having a molecular weight of 8.0 × 10 3 or less of less than 1% by weight. Separator.
(3) The nonaqueous electrolyte battery separator according to (1) or (2), wherein the nonaqueous electrolyte battery separator has a puncture strength of 100 to 2000 g.
(4) The nonaqueous electrolyte according to any one of (1) to (3), wherein the heat-resistant porous layer contains an inorganic filler in a weight fraction of 50% by weight to 95% by weight. Battery separator.
(5) The non-aqueous electrolyte battery separator according to (4), wherein the inorganic filler is mainly composed of a metal hydroxide.
(6) The heat-resistant polymer is one or more selected from the group consisting of aromatic polyamide, polyimide, polyethersulfone, polysulfone, polyetherketone, and polyetherimide. The nonaqueous electrolyte battery separator according to any one of 1) to (5).
(7) The above-mentioned aromatic polyamide is produced by polymerizing an aromatic dicarboxylic acid halide and an aromatic diamine in an organic polar solvent which is a good solvent for the polyamide to be produced. (6) The nonaqueous electrolyte battery separator according to (6).
(8) The nonaqueous electrolyte battery separator according to any one of (1) to (7), wherein the base material is a microporous film made of a thermoplastic resin mainly composed of polyolefin.
(9) The nonaqueous electrolyte battery separator according to any one of (1) to (8), wherein the nonaqueous electrolyte battery separator is a separator for a lithium ion secondary battery.
(10) A base material mainly made of a thermoplastic resin and having a pore or void inside and having a shutdown function, and a heat-resistant porous material mainly made of aromatic polyamide and laminated on one or both sides of the base material A nonaqueous electrolyte battery separator manufacturing method according to the above (1) comprising a porous layer, wherein (i) an organic solvent that is a good solvent for the polyamide that forms an aromatic dicarboxylic acid halide and an aromatic diamine To produce an aromatic polyamide having a molecular weight distribution Mw / Mn of 1 <Mw / Mn <5 and a weight average molecular weight Mw of 8.0 × 10 3 to 1.0 × 10 6 And (ii) a step of coating the obtained water-soluble organic solvent solution of the aromatic polyamide on one or both sides of the substrate; and (iii) water or water on the coated substrate. Mixing of organic solvents A non-aqueous electrolyte battery comprising: a step of solidifying an aromatic polyamide by dipping in a coagulation solution comprising a liquid; and (iv) a step of washing and drying the substrate after the coagulation step. Separator manufacturing method.
(11) A base material mainly formed of a thermoplastic resin and having a shutdown function and having pores or voids inside, and a shutdown function, and a base material mainly formed of a meta-type aromatic polyamide on one or both surfaces of the base material A method for producing a nonaqueous electrolyte battery separator according to (1), comprising a laminated heat-resistant porous layer, wherein (i) a meta-type aromatic dicarboxylic acid halide and a meta-type aromatic diamine are produced. The resulting polyamide is reacted in a non-good organic solvent to form a solution or dispersion, which is contacted with an acid acceptor aqueous solution to complete the reaction, and the molecular weight distribution Mw / Mn is 1 <Mw / Mn <5. And a step of producing a meta-type aromatic polyamide having a weight average molecular weight Mw of 8.0 × 10 3 or more and 1.0 × 10 6 or less, and (ii) A step of applying a water-soluble organic solvent solution of an aromatic polyamide to one or both sides of the substrate; and (iii) coagulation of the coated substrate with water or a mixture of water and the organic solvent. A nonaqueous electrolyte battery separator comprising: a step of solidifying the meta-type aromatic polyamide by dipping in a liquid; and (iv) a step of washing and drying the substrate after the solidification step. Manufacturing method.
(12) A non-aqueous electrolyte secondary battery that obtains an electromotive force by doping or dedoping lithium, wherein the non-aqueous electrolyte battery separator according to any one of (1) to (9) is used. Non-aqueous electrolyte secondary battery.
本発明の非水電解質電池セパレータにおいては、ポリオレフィン微多孔膜等の基材の、片面又は両面に積層される耐熱性多孔質層を形成するための、芳香族ポリアミド等の耐熱性高分子として、分子量分布(Mw/Mn)が、1<Mw/Mn<5であり、且つ、重量平均分子量(Mw)が、8.0×103〜1.0×106の範囲にあるものを用いることを特徴とする。本発明で用いられる耐熱性高分子の分子量分布は狭いので、得られたセパレータの機械的強度、耐熱性が向上する。また、基材表面の孔にドープが染み込みにくくなり、基材表面の孔を塞がない。界面での閉塞がないので、基材のシャットダウンを妨げず、且つ、界面での膜抵抗の増加も防ぐことができるという効果が得られる。 In the non-aqueous electrolyte battery separator of the present invention, as a heat-resistant polymer such as an aromatic polyamide for forming a heat-resistant porous layer laminated on one side or both sides of a substrate such as a polyolefin microporous membrane, Use a molecular weight distribution (Mw / Mn) of 1 <Mw / Mn <5 and a weight average molecular weight (Mw) in the range of 8.0 × 10 3 to 1.0 × 10 6. It is characterized by. Since the molecular weight distribution of the heat-resistant polymer used in the present invention is narrow, the mechanical strength and heat resistance of the obtained separator are improved. Moreover, it becomes difficult for the dope to penetrate into the holes on the surface of the substrate, and the holes on the surface of the substrate are not blocked. Since there is no blockage at the interface, there is an effect that the shutdown of the base material is not hindered and the increase of the film resistance at the interface can be prevented.
また、本発明の非水電解質電池セパレータは、耐熱性が高く熱収縮が小さいので、ポリオレフィン微多孔膜等の基材と組み合わせた場合に、塗布後のポリオレフィンのアニール効果が得られ、セパレータ全体の熱収縮率も低下するという特徴がある。これにより、本発明の非水電解質電池セパレータは、十分な耐熱性およびシャットダウン特性に加えて、優れたイオン透過性、ハンドリング性、安全性を有するようになる。従って、かかる非水電解質電池セパレータを用いることで、膜抵抗が小さく安全性に優れた非水電解質二次電池を提供することができる。 In addition, since the nonaqueous electrolyte battery separator of the present invention has high heat resistance and small thermal shrinkage, when combined with a substrate such as a polyolefin microporous film, an annealing effect of the polyolefin after coating can be obtained, and the entire separator The heat shrinkage rate is also reduced. Thereby, the nonaqueous electrolyte battery separator of the present invention has excellent ion permeability, handling properties, and safety in addition to sufficient heat resistance and shutdown characteristics. Therefore, by using such a nonaqueous electrolyte battery separator, it is possible to provide a nonaqueous electrolyte secondary battery having low membrane resistance and excellent safety.
[非水電解質電池セパレータ]
本発明は、主として熱可塑性樹脂にて形成され内部に空孔ないし空隙を有しシャットダウン機能を有する基材と、主として耐熱性高分子にて形成され前記基材の片面又は両面に積層された耐熱性多孔質層とを備えた非水電解質電池セパレータにおいて、前記耐熱性高分子として、分子量分布(Mw/Mn)が1<Mw/Mn<5であり、且つ、重量平均分子量(Mw)が8.0×103〜1.0×106のものを用いることを特徴とするものである。分子量分布が5以上の場合は、機械的強度や耐熱性が劣るので不適当である。また、重量平均分子量が8千未満の場合は、機械的強度が低く、百万を超える場合には、耐熱性高分子の塗工性が悪くなり、均一に塗工しにくくなるので不適当である。
[Nonaqueous electrolyte battery separator]
The present invention relates to a base material mainly formed of a thermoplastic resin and having pores or voids therein and having a shutdown function, and a heat-resistant layer mainly formed of a heat-resistant polymer and laminated on one or both sides of the base material. In the non-aqueous electrolyte battery separator including the porous porous layer, as the heat-resistant polymer, the molecular weight distribution (Mw / Mn) is 1 <Mw / Mn <5 and the weight average molecular weight (Mw) is 8 0.0 × 10 3 to 1.0 × 10 6 are used. When the molecular weight distribution is 5 or more, the mechanical strength and heat resistance are inferior. In addition, when the weight average molecular weight is less than 8,000, the mechanical strength is low, and when it exceeds 1 million, the heat-resistant polymer is poorly coated and is difficult to apply uniformly. is there.
本発明において好ましい耐熱性高分子は、分子量分布(Mw/Mn)が1<Mw/Mn<5で、重量平均分子量(Mw)が8.0×103〜1.0×106で、且つ、分子量8000以下の低分子量ポリマーの含有量が、1重量%未満のものである。 In the present invention, a preferred heat-resistant polymer has a molecular weight distribution (Mw / Mn) of 1 <Mw / Mn <5, a weight average molecular weight (Mw) of 8.0 × 10 3 to 1.0 × 10 6 , and The content of a low molecular weight polymer having a molecular weight of 8000 or less is less than 1% by weight.
本発明の非水電解質電池セパレータの膜厚は30μm以下が好ましく、さらに20μm以下が好ましい。セパレータの膜厚が30μmを超えるとこれを適用した電池のエネルギー密度や出力特性が低下し好ましくない。非水電解質電池セパレータの物性としては、ガーレ値(JIS・P8117)が10〜1000sec/100cc、好ましくは100〜400sec/100ccである。ガーレ値が10sec/100cc未満である場合は、微多孔膜のガーレ値が低過ぎ、シャットダウン機能の低下が著しく、実用的でない。ガーレ値が1000sec/100ccを超えると、イオン透過性が不十分となり、セパレータの膜抵抗が増加して電池の出力低下を招くという不具合が生じる。膜抵抗は0.5〜10ohm・cm2、好ましくは1〜5ohm・cm2である。突き刺し強度は10〜1000g、好ましくは200〜600gの範囲のものである。 The film thickness of the nonaqueous electrolyte battery separator of the present invention is preferably 30 μm or less, more preferably 20 μm or less. When the thickness of the separator exceeds 30 μm, the energy density and output characteristics of a battery to which the separator is applied are lowered, which is not preferable. As the physical properties of the nonaqueous electrolyte battery separator, the Gurley value (JIS P8117) is 10 to 1000 sec / 100 cc, preferably 100 to 400 sec / 100 cc. When the Gurley value is less than 10 sec / 100 cc, the Gurley value of the microporous membrane is too low, and the shutdown function is remarkably lowered, which is not practical. When the Gurley value exceeds 1000 sec / 100 cc, the ion permeability becomes insufficient, resulting in a problem that the membrane resistance of the separator is increased and the output of the battery is lowered. The membrane resistance is 0.5 to 10 ohm · cm 2 , preferably 1 to 5 ohm · cm 2 . The puncture strength is in the range of 10 to 1000 g, preferably 200 to 600 g.
本発明の、熱可塑性樹脂にて形成され内部に空孔ないし空隙を有しシャットダウン機能を有する基材としては、微多孔膜、不織布、紙状シート、その他三次元ネットーワーク構造を有するシート等を挙げることができるが、特に、微多孔膜が好ましい。微多孔膜とは、内部に多数の微細孔を有し、これら微細孔が連結された構造となっており、一方の面から他方の面へと気体あるいは液体が通過可能となった膜を意味する。熱可塑性樹脂としては、融点200℃未満の熱可塑性樹脂が適当であり、好ましくはポリオレフィンであり、特に好ましいのは、ポリエチレンである。従って、ポリオレフィン、特にポリエチレンの微多孔膜が好ましい。ポリエチレンは、特に限定されるものではないが、高密度ポリエチレンや、高密度ポリエチレンと超高分子量ポリエチレンの混合物が好適である。また、例えば、ポリエチレン以外に、ポリプロピレン、ポリメチルペンテン等の他のポリオレフィンを混合して用いても良い。なお、本発明の基材は、主として、即ち、約90重量%以上が熱可塑性樹脂からなるものであれば良く、約10重量%以下の、電池特性に影響を与えない他の成分を含んでいても良い。 The substrate of the present invention formed of a thermoplastic resin and having a pore or void inside and having a shutdown function includes a microporous film, a nonwoven fabric, a paper-like sheet, and other sheets having a three-dimensional network structure. Among them, a microporous membrane is particularly preferable. A microporous membrane means a membrane that has a large number of micropores inside and has a structure in which these micropores are connected, allowing gas or liquid to pass from one surface to the other. To do. As the thermoplastic resin, a thermoplastic resin having a melting point of less than 200 ° C. is suitable, preferably a polyolefin, and particularly preferably polyethylene. Therefore, a microporous membrane of polyolefin, particularly polyethylene, is preferred. The polyethylene is not particularly limited, but high-density polyethylene or a mixture of high-density polyethylene and ultrahigh molecular weight polyethylene is suitable. For example, in addition to polyethylene, other polyolefins such as polypropylene and polymethylpentene may be mixed and used. In addition, the base material of the present invention is not limited as long as it is mainly composed of a thermoplastic resin at about 90% by weight or more, and contains about 10% by weight or less of other components that do not affect the battery characteristics. May be.
ポリエチレン等の微多孔膜の膜厚は5μm以上18μm以下であることが好ましい。該微多孔膜の膜厚が5μmより薄いと引張強度や突刺強度といった機械物性が不十分となり、該微多孔膜の膜厚が18μmより厚いと適切なセパレータ厚みを実現することが困難となるため好ましくない。該微多孔膜の空孔率は20〜60%のものが好ましい。微多孔膜の空孔率が20%未満となるとセパレータの膜抵抗が高くなり過ぎ、電池の出力を顕著に低下させるため好ましくない。また、60%を超えると、シャットダウン特性の低下が顕著となり好ましくない。該微多孔膜のガーレ値(JIS・P8117)は、10sec/100cc以上、500sec/100cc以下が好ましい。微多孔膜のガーレ値が500sec/100ccより高いと、イオン透過性が不十分となりセパレータの抵抗が高くなるという不具合が生じる。微多孔膜のガーレ値が10sec/100ccより低いとシャットダウン機能の低下が著しく実用的でない。該微多孔膜の突刺強度は、10g以上が好適である。 The film thickness of the microporous film such as polyethylene is preferably 5 μm or more and 18 μm or less. If the thickness of the microporous film is less than 5 μm, mechanical properties such as tensile strength and puncture strength are insufficient, and if the thickness of the microporous film is greater than 18 μm, it is difficult to achieve an appropriate separator thickness. It is not preferable. The porosity of the microporous membrane is preferably 20 to 60%. When the porosity of the microporous membrane is less than 20%, the membrane resistance of the separator becomes too high, and the output of the battery is remarkably lowered, which is not preferable. On the other hand, if it exceeds 60%, the shutdown characteristic is remarkably deteriorated. The Gurley value (JIS P8117) of the microporous membrane is preferably 10 sec / 100 cc or more and 500 sec / 100 cc or less. If the Gurley value of the microporous membrane is higher than 500 sec / 100 cc, the ion permeability is insufficient and the resistance of the separator increases. When the Gurley value of the microporous film is lower than 10 sec / 100 cc, the shutdown function is remarkably deteriorated. The puncture strength of the microporous membrane is preferably 10 g or more.
本発明で用いられる耐熱性高分子は、融点200℃以上のポリマーあるいは融点を有しないが分解温度が200℃以上のポリマーが適当であり、好ましくは、芳香族ポリアミド、ポリイミド、ポリエーテルスルホン、ポリスルホン、ポリエーテルケトン、ポリエーテルイミドからなる群から選ばれる1種又は2種以上ものである。耐熱性高分子の中で特に好ましいのは、芳香族ポリアミド、なかでもポリメタフェニレンイソフタルアミド等のメタアラミドである。ポリエチレンとメタアラミドはなじみが良く良好な接着性示すので、本発明においては、特に好ましい組合わせである。 As the heat-resistant polymer used in the present invention, a polymer having a melting point of 200 ° C. or higher or a polymer having no melting point but having a decomposition temperature of 200 ° C. or higher is suitable, preferably aromatic polyamide, polyimide, polyethersulfone, polysulfone. , One or more selected from the group consisting of polyetherketone and polyetherimide. Particularly preferred among the heat resistant polymers are aromatic polyamides, especially meta-aramids such as polymetaphenylene isophthalamide. Polyethylene and meta-aramid are well-suited and exhibit good adhesion, and are therefore a particularly preferred combination in the present invention.
耐熱性高分子の製法は特に問わないが、溶液重合で得られたものが好ましい。溶液重合によると、耐熱性高分子の分子量分布と重量平均分子量を、前記本発明の範囲内に調整することが容易である。特に、芳香族ジアミンと芳香族ジカルボン酸クロライドとを、有機極性溶媒中で重合させることによって得られる芳香族ポリアミド、とりわけメタアラミドが好ましく用いられる。いわゆる界面重合で得られたものでも使用できる。界面重合法で製造すると、分子量分布が広いものが得られ易いが、低分子量のものをカットするなどして、分子量や分子量分布を調整すれば良い。 The production method of the heat-resistant polymer is not particularly limited, but those obtained by solution polymerization are preferable. According to the solution polymerization, it is easy to adjust the molecular weight distribution and the weight average molecular weight of the heat-resistant polymer within the scope of the present invention. In particular, an aromatic polyamide obtained by polymerizing an aromatic diamine and an aromatic dicarboxylic acid chloride in an organic polar solvent, particularly meta-aramid, is preferably used. Those obtained by so-called interfacial polymerization can also be used. When produced by the interfacial polymerization method, it is easy to obtain a product having a wide molecular weight distribution, but the molecular weight and the molecular weight distribution may be adjusted by cutting a low molecular weight product.
かかる耐熱性高分子にて形成される耐熱性多孔質層とは、内部に多数の微細孔を有し、これら微細孔が連結された構造となっており、一方の面から他方の面へと気体あるいは液体が通過可能となった層を意味する。なお、耐熱性多孔質層は、主として、即ち、約90重量%以上が耐熱性高分子からなるものであれば良く、約10重量%以下の、電池特性に影響を与えない他の成分を含んでいても良い。 A heat-resistant porous layer formed of such a heat-resistant polymer has a structure in which a large number of micropores are connected inside and these micropores are connected to each other. It means a layer through which gas or liquid can pass. The heat-resistant porous layer should be mainly composed of heat-resistant polymer in an amount of about 90% by weight or more, and contains about 10% by weight or less of other components that do not affect the battery characteristics. You can leave.
本発明において該耐熱性多孔質層は、前記微多孔膜等の基材の少なくとも一方の面に形成すればよいが、ハンドリング性、耐久性および熱収縮の抑制効果の観点から、表裏両面に形成した方がより好ましい。そして、耐熱性多孔質層が微多孔膜等の基材の両面に形成されている場合は該耐熱性多孔質層の厚みの合計が3μm以上12μm以下であるか、または、該耐熱性多孔質層が該微多孔膜等の基材の片面にのみ形成されている場合は該耐熱性多孔質層の厚みが3μm以上12μm以下であることが好ましい。いずれの場合においても、該耐熱性多孔質層の厚みの合計が3μm未満となると、十分な耐熱性、特に熱収縮抑制効果が得られなくなる。一方、該耐熱性多孔質層の厚みの合計が12μmを超えると、適切なセパレータ厚みを実現することが困難となる。該耐熱性多孔質層の空孔率は60〜90%の範囲が好適である。該耐熱性多孔質層の空孔率が90%を超えると耐熱性が不十分となる傾向にあり、60%より低いとサイクル特性や保存特性、放電性が低下する傾向となり好ましくない。 In the present invention, the heat-resistant porous layer may be formed on at least one surface of a substrate such as the microporous membrane, but it is formed on both front and back surfaces from the viewpoint of handling properties, durability, and the effect of suppressing heat shrinkage. Is more preferable. And when the heat resistant porous layer is formed on both surfaces of a substrate such as a microporous membrane, the total thickness of the heat resistant porous layer is 3 μm or more and 12 μm or less, or the heat resistant porous layer When the layer is formed only on one side of the substrate such as the microporous membrane, the thickness of the heat-resistant porous layer is preferably 3 μm or more and 12 μm or less. In any case, when the total thickness of the heat-resistant porous layer is less than 3 μm, sufficient heat resistance, particularly a heat shrinkage suppressing effect cannot be obtained. On the other hand, when the total thickness of the heat-resistant porous layer exceeds 12 μm, it is difficult to realize an appropriate separator thickness. The porosity of the heat resistant porous layer is preferably in the range of 60 to 90%. If the porosity of the heat-resistant porous layer exceeds 90%, the heat resistance tends to be insufficient, and if it is lower than 60%, the cycle characteristics, storage characteristics, and discharge characteristics tend to decrease, such being undesirable.
本発明においては、前記耐熱性多孔質層に、重量分率50〜95重量%の範囲で、無機フィラーが含まれているのが好ましい。無機フィラーとは、無機微粒子であり、その種類は特に限定されるものではないが、好ましいのは、アルミナ、チタニア、シリカ、ジルコニアなどの酸化物、炭酸塩、リン酸塩、水酸化物などである。特に、金属水酸化物が好ましい。金属水酸化物としては、水酸化アルミニウム、水酸化マグネシウム、水酸化カルシウム、水酸化クロム、水酸化ジルコニウム、水酸化ニッケル、水酸化ホウ素、若しくはこれらの2種以上の組合せが好適である。無機フィラーの平均粒子径は、0.1〜1μmの範囲にあるものが好ましい。 In the present invention, it is preferable that the heat resistant porous layer contains an inorganic filler in a range of 50 to 95% by weight. The inorganic filler is an inorganic fine particle, and the kind thereof is not particularly limited, but is preferably an oxide such as alumina, titania, silica, zirconia, carbonate, phosphate, hydroxide, etc. is there. In particular, a metal hydroxide is preferable. As the metal hydroxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, boron hydroxide, or combinations of two or more thereof are suitable. The average particle diameter of the inorganic filler is preferably in the range of 0.1 to 1 μm.
無機フィラーの量が50〜95重量%の範囲であると、無機フィラーは耐熱性高分子と十分になじみ、分散性も良い。また、無機フィラーの作用で、耐熱性多孔質層を水中凝固により形成させる際に、耐熱性高分子の低分子量ポリマーが凝固液中に流出しにくくなるので、好適な孔形成が可能になる。そして、後述のガーレ値や膜抵抗が更に低くなるという効果も得られる。 When the amount of the inorganic filler is in the range of 50 to 95% by weight, the inorganic filler is sufficiently compatible with the heat-resistant polymer and has good dispersibility. In addition, when the heat-resistant porous layer is formed by solidification in water due to the action of the inorganic filler, it is difficult for the low-molecular weight polymer of the heat-resistant polymer to flow out into the coagulation liquid, so that suitable pore formation is possible. And the effect that the below-mentioned Gurley value and film resistance become still lower is also acquired.
また、無機フィラーは、本発明の非水電解質電池セパレータを難燃化する上で有効に機能する。例えば、無機フィラーとして金属水酸化物を用いた場合には、金属水酸化物を加熱すると脱水反応が起こり酸化物となり、水が放出される。更に、この脱水反応は大きな吸熱を伴う反応である。この脱水反応時に水を放出することと、この反応の吸熱により、難燃効果が得られる。また、水を放出するため可燃性である電解液を水で希釈し、セパレータだけでなく電解液にも効果があり、電池そのものを難燃化する上で有効である。 The inorganic filler functions effectively in making the nonaqueous electrolyte battery separator of the present invention flame retardant. For example, when a metal hydroxide is used as the inorganic filler, when the metal hydroxide is heated, a dehydration reaction occurs to become an oxide, and water is released. Furthermore, this dehydration reaction is a reaction with a large endotherm. The release of water during this dehydration reaction and the endothermic effect of this reaction provide a flame retardant effect. In addition, an electrolyte that is flammable to release water is diluted with water and is effective not only for the separator but also for the electrolyte, and is effective in making the battery itself flame-retardant.
無機フィラーとしての金属水酸化物は、ハンドリング性の観点からも好ましい。また、金属水酸化物は、アルミナのような金属酸化物と比較して軟らかいため、従来のセパレータにあるような問題、即ち、セパレータに含まれる無機フィラーによって、製造時の各工程にて使用する部品が磨耗してしまうといった、ハンドリング性に関する問題が発生しにくいという点でも好ましい。 The metal hydroxide as the inorganic filler is also preferable from the viewpoint of handling properties. In addition, since metal hydroxide is softer than metal oxide such as alumina, it is used in each process at the time of manufacture depending on the problem with conventional separators, that is, the inorganic filler contained in the separator. It is also preferable in that a problem relating to handling properties such as wear of parts is unlikely to occur.
[非水電解質電池セパレータの製造方法]
本発明の非水電解質電池セパレータの製造方法は特に限定されないが、例えば、以下の(i)〜(iv)の工程を経て製造することが可能である。即ち、(i)分子量分布(Mw/Mn)が1<Mw/Mn<5であり、且つ、重量平均分子量(Mw)が8.0×103〜1.0×106である耐熱性高分子を製造し、この耐熱性高分子を水溶性有機溶剤に溶かし塗工液を製造する工程と、(ii)得られた塗工液を、ポリオレフィンの微多孔膜等の基材の片面又は両面に塗工する工程と、(iii)塗工された前記基材を、水又は水と前記有機溶剤の混合液からなる凝固液中に浸漬して耐熱性高分子を凝固させる工程と、その後、(iv)水洗し乾燥する工程、を実施することからなる製造方法である。
[Method for producing non-aqueous electrolyte battery separator]
Although the manufacturing method of the nonaqueous electrolyte battery separator of this invention is not specifically limited, For example, it is possible to manufacture through the following processes (i)-(iv). That is, (i) high heat resistance with molecular weight distribution (Mw / Mn) of 1 <Mw / Mn <5 and weight average molecular weight (Mw) of 8.0 × 10 3 to 1.0 × 10 6 A step of producing a molecule and dissolving the heat-resistant polymer in a water-soluble organic solvent to produce a coating solution; and (ii) applying the obtained coating solution to one or both sides of a substrate such as a microporous membrane of polyolefin. And (iii) a step of immersing the coated substrate in water or a coagulating liquid composed of water and the organic solvent to coagulate the heat-resistant polymer, and (Iv) A manufacturing method comprising carrying out a step of washing and drying.
上記の製造方法においては、耐熱性高分子として芳香族ポリアミドを用いるのが好ましい。この場合、前記工程(i)において、芳香族ジカルボン酸ハライドと芳香族ジアミンを、生成するポリアミドに対し良溶媒である有機溶媒中で反応せしめて芳香族ポリアミドを製造する、いわゆる溶液重合法を適用することが可能である。この方法の場合、耐熱性高分子としてはメタ型芳香族ポリアミドの他にパラ型の芳香族ポリアミドも製造することが可能である。 In the above production method, it is preferable to use an aromatic polyamide as the heat-resistant polymer. In this case, in the step (i), a so-called solution polymerization method in which an aromatic dicarboxylic acid halide and an aromatic diamine are reacted in an organic solvent, which is a good solvent, with the resulting polyamide is applied. Is possible. In the case of this method, as the heat-resistant polymer, it is possible to produce a para type aromatic polyamide in addition to a meta type aromatic polyamide.
この溶液重合法の場合、得られた芳香族ポリアミドは、分子量分布が狭く、且つ、高分子量のものが得られ易いので、そのまま、本発明における分子量分布Mw/Mnが1<Mw/Mn<5で、重量平均分子量Mwが8.0×103〜1.0×106という条件を満足し易い。このような分子量分布の狭いポリマーを得るためには、芳香族ジカルボン酸ハライドと芳香族ジアミンの反応モル比を同等にすればよい。すなわち、芳香族ジアミンと芳香族ジカルボン酸ハライドとの比率(モル比)は、メタ型芳香族ジカルボン酸ハライドが49.95モル%以上、かつ、メタ型芳香族ジアミンが50.05モル%以下か、または、芳香族ジカルボン酸ハライドが50.05モル%以下、かつ、芳香族ジアミンが49.95モル%以上であることが好ましい。また、芳香族ジアミンを芳香族ジカルボン酸ハライドに添加する速度を早くすることでも調整できる。また、末端封止剤を用いても調節できる。末端封止剤としては、アニリンなどの1級又は2級モノアミンや、無水酢酸、無水フタル酸などの有機酸の無水物、塩化アセチル、塩化ベンゾイルなどの酸クロライド、又はこれらを2種以上組み合わせたものを用いることができる。 In the case of this solution polymerization method, since the obtained aromatic polyamide has a narrow molecular weight distribution and a high molecular weight is easily obtained, the molecular weight distribution Mw / Mn in the present invention is 1 <Mw / Mn <5. Therefore, it is easy to satisfy the condition that the weight average molecular weight Mw is 8.0 × 10 3 to 1.0 × 10 6 . In order to obtain such a polymer having a narrow molecular weight distribution, the reaction molar ratio of the aromatic dicarboxylic acid halide and the aromatic diamine may be made equal. That is, the ratio (molar ratio) between the aromatic diamine and the aromatic dicarboxylic acid halide is 49.95 mol% or more for the meta type aromatic dicarboxylic acid halide and 50.05 mol% or less for the meta type aromatic diamine. Alternatively, it is preferable that the aromatic dicarboxylic acid halide is 50.05 mol% or less and the aromatic diamine is 49.95 mol% or more. It can also be adjusted by increasing the rate at which the aromatic diamine is added to the aromatic dicarboxylic acid halide. It can also be adjusted by using an end-capping agent. As end-capping agents, primary or secondary monoamines such as aniline, organic acid anhydrides such as acetic anhydride and phthalic anhydride, acid chlorides such as acetyl chloride and benzoyl chloride, or a combination of two or more of these Things can be used.
この溶液重合法において、ポリアミドに対し良溶媒である有機溶媒としては、特に限定されないが、具体的には極性溶剤が好ましく、例えばN−メチルピロリドン、ジメチルアセトアミド、ジメチルホルムアミド、ジメチルスルホキシドなどが挙げられる。芳香族ジカルボン酸ハライドとしては、イソフタル酸クロライド、イソフタル酸ブロマイドなどのイソフタル酸ハライド及びこれらの芳香環にハロゲン、炭素数1〜3のアルコキシ基などの置換基を有する誘導体、例えば3−クロルイソフタル酸クロライド、3−メトキシイソフタル酸クロライドなど、を使用することができる。芳香族ジアミンとしては、メタフェニレンジアミン、3,4'−ジアミノジフェニルエーテル、3,4'−ジアミノジフェニルスルホンなど及びこれらの芳香環にハロゲン、炭素数1〜3のアルキルキ基などの置換基を有する誘導体、例えば2,4−トルイレンジアミン、2,6−トルイレンジアミン、2,4−ジアミノクロルベンゼン、2,6−ジアミノクロルベンゼンなどを使用することができる。 In this solution polymerization method, the organic solvent which is a good solvent for polyamide is not particularly limited, but specifically, a polar solvent is preferable, and examples thereof include N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide and the like. . Examples of the aromatic dicarboxylic acid halide include isophthalic acid halides such as isophthalic acid chloride and isophthalic acid bromide, and derivatives having substituents such as halogen and alkoxy groups having 1 to 3 carbon atoms on the aromatic ring, such as 3-chloroisophthalic acid. Chloride, 3-methoxyisophthalic acid chloride, and the like can be used. Examples of aromatic diamines include metaphenylene diamine, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl sulfone, and derivatives having substituents such as halogen and alkyl groups having 1 to 3 carbon atoms on these aromatic rings. For example, 2,4-toluylenediamine, 2,6-toluylenediamine, 2,4-diaminochlorobenzene, 2,6-diaminochlorobenzene and the like can be used.
上述のようにして溶液重合を行った後のポリマー溶液には、重合反応で副生した塩化水素などのハロゲン化水素が含まれている。このため、これを溶媒可溶性の塩を形成する中和剤、例えば炭酸カルシウム、炭酸リチウム、水酸化カルシウム、水酸化リチウムなどの無機アルカリを添加して中和する処理が必要である。 The polymer solution after performing the solution polymerization as described above contains hydrogen halide such as hydrogen chloride by-produced by the polymerization reaction. For this reason, the neutralization agent which forms a solvent soluble salt, for example, inorganic alkalis, such as calcium carbonate, lithium carbonate, calcium hydroxide, lithium hydroxide, is added and the process of neutralizing is required.
本発明では、芳香族ポリアミドの製造方法は上述したものに限らない。すなわち、前記工程(i)において、メタ型芳香族ジカルボン酸ハライドとメタ型芳香族ジアミンを、生成するポリアミドに対し良溶媒でない有機溶媒、例えば、テトラヒドロフラン中で反応せしめて溶液若しくは分散液を作り、これを、炭酸ソーダ等の酸受容剤の水溶液と接触させ反応を完結せしめる、いわゆる界面重合法でメタ型芳香族ポリアミドを製造することも可能である。 In the present invention, the method for producing the aromatic polyamide is not limited to that described above. That is, in the step (i), a meta-type aromatic dicarboxylic acid halide and a meta-type aromatic diamine are reacted in an organic solvent that is not a good solvent for the polyamide to be produced, for example, tetrahydrofuran to form a solution or dispersion. It is also possible to produce a meta-type aromatic polyamide by a so-called interfacial polymerization method in which this is brought into contact with an aqueous solution of an acid acceptor such as sodium carbonate to complete the reaction.
このような界面重合法によって得られたメタ型芳香族ポリアミドは、分子量分布が広くなりがちであるが、上述したように芳香族ジカルボン酸ハライドと芳香族ジアミンの反応モル比を同等にすれば、分子量分布Mw/Mnが1<Mw/Mn<5で、重量平均分子量Mwが8.0×103〜1.0×106という条件を満足させることができる。なお、芳香族ジカルボン酸ハライドおよび芳香族ジアミンおよび末端封止剤は、上述した溶液重合法のものを用いることができる。 The meta-type aromatic polyamide obtained by such an interfacial polymerization method tends to have a broad molecular weight distribution, but if the reaction molar ratio of the aromatic dicarboxylic acid halide and the aromatic diamine is equalized as described above, The conditions that the molecular weight distribution Mw / Mn is 1 <Mw / Mn <5 and the weight average molecular weight Mw is 8.0 × 10 3 to 1.0 × 10 6 can be satisfied. In addition, the thing of the solution polymerization method mentioned above can be used for aromatic dicarboxylic acid halide, aromatic diamine, and terminal blocker.
前記工程(i)においては、上述のようにして作製した芳香族ポリアミドを水溶性有機溶剤に溶かして塗工液を作製する。この水溶性有機溶剤としては、特に限定されないが、具体的には極性溶剤が好ましく、例えばN−メチルピロリドン、ジメチルアセトアミド、ジメチルホルムアミド、ジメチルスルホキシドなどが挙げられる。また、これらの水溶性有機溶剤に耐熱性高分子に対して貧溶剤となる溶剤も一部混合して用いることもできる。このような溶剤を適用することでミクロ相分離構造が誘発され、耐熱性多孔質層を形成する上で多孔化が容易となる。該貧溶剤としては、アルコールの類が好適であり、特にグリコールのような多価アルコールが好適である。塗工液中のポリマー濃度は4〜9重量%が好ましい。なお、溶液重合法にてポリマーを作製した場合は、中和処理後のポリマー溶液をそのまま塗工液として使用することができる。 In the step (i), the aromatic polyamide prepared as described above is dissolved in a water-soluble organic solvent to prepare a coating solution. Although it does not specifically limit as this water-soluble organic solvent, Specifically, a polar solvent is preferable, for example, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide etc. are mentioned. In addition, a solvent that becomes a poor solvent for the heat-resistant polymer may be mixed with these water-soluble organic solvents. By applying such a solvent, a microphase separation structure is induced, and the formation of a heat-resistant porous layer is facilitated. As the poor solvent, alcohols are preferable, and polyhydric alcohols such as glycol are particularly preferable. The polymer concentration in the coating solution is preferably 4 to 9% by weight. In addition, when a polymer is produced by a solution polymerization method, the polymer solution after the neutralization treatment can be used as it is as a coating solution.
耐熱性多孔質層として、重量分率で50〜95重量%の無機フィラーを含むものを作製する場合には、工程(i)において、耐熱性高分子の水溶性有機溶剤溶液に無機フィラーを分散させ、塗工用スラリーを作製すれば良い。本発明においては、かかる塗工用スラリーも、工程(i)の塗工液の概念に含まれるものである。無機フィラーの分散性が良好でない場合は、無機フィラーをシランカップリング剤等で表面処理し、分散性を改善する手法も適用可能である。 When producing a heat-resistant porous layer containing 50 to 95% by weight of inorganic filler by weight fraction, in step (i), the inorganic filler is dispersed in a water-soluble organic solvent solution of a heat-resistant polymer. The slurry for coating may be prepared. In the present invention, such a coating slurry is also included in the concept of the coating liquid in the step (i). When the dispersibility of the inorganic filler is not good, a method of improving the dispersibility by surface-treating the inorganic filler with a silane coupling agent or the like is also applicable.
工程(ii)では、微多孔膜等の基材の少なくとも一方の表面に耐熱性高分子の塗工液を塗工する。本発明においては、微多孔膜の基材の両面に塗工するのが好ましい。微多孔膜への塗工量は2〜3g/m2程度が好ましい。塗工する方法は、ナイフコーター法、グラビアコーター法、スクリーン印刷法、マイヤーバー法、ダイコーター法、リバースロールコーター法、インクジェット法、スプレー法、ロールコーター法などが挙げられる。塗膜を均一に塗布するという観点において、特にリバースロールコーター法が好適である。より具体的には、例えば、ポリエチレン微多孔膜等の基材の両面に耐熱性高分子の塗工液を塗工する場合は、一対のマイヤーバーの間を通して基材の両面に過剰に塗工液を塗布し、これを一対のリバースロールコーターの間を通し、過剰な塗工液を掻き落すことで精密計量するという方法が挙げられる。 In step (ii), a heat-resistant polymer coating solution is applied to at least one surface of a substrate such as a microporous membrane. In this invention, it is preferable to apply on both surfaces of the substrate of the microporous membrane. The coating amount on the microporous membrane is preferably about 2 to 3 g / m 2 . Examples of the coating method include knife coater method, gravure coater method, screen printing method, Mayer bar method, die coater method, reverse roll coater method, ink jet method, spray method, roll coater method and the like. From the viewpoint of uniformly applying the coating film, the reverse roll coater method is particularly suitable. More specifically, for example, when applying a coating solution of a heat resistant polymer on both surfaces of a substrate such as a polyethylene microporous membrane, it is applied excessively on both surfaces of the substrate through a pair of Meyer bars. There is a method of applying a liquid and passing it between a pair of reverse roll coaters and scraping off an excessive coating liquid to measure precisely.
工程(iii)では、塗工された微多孔膜等の基材を、耐熱性高分子を凝固させることが可能な凝固液中に浸漬することで、耐熱性高分子を凝固させ、多孔質層を成形する。凝固の方法としては、凝固液をスプレーで吹き付ける方法や、凝固液の入った浴(凝固浴)中に浸漬する方法などが挙げられる。凝固液は、耐熱性高分子を凝固できるものであれば特に限定されないが、水又は塗工液に用いた有機溶媒に水を適当量混合させたものが好ましい。ここで、水の混合量は凝固液に対して40〜80重量%が好適である。水の量が40重量%より少ないと耐熱性高分子を凝固するのに必要な時間が長くなったり、凝固が不十分になるという問題が生じる。また、80重量%より多いと溶剤回収においてコスト高となったり、凝固液と接触する表面の凝固が速すぎ、表面が十分に多孔化されないという問題が生じる。 In the step (iii), the heat-resistant polymer is coagulated by immersing the coated substrate such as a microporous film in a coagulating liquid capable of coagulating the heat-resistant polymer, and the porous layer Is molded. Examples of the coagulation method include a method of spraying a coagulation liquid with a spray and a method of immersing in a bath (coagulation bath) containing the coagulation liquid. The coagulation liquid is not particularly limited as long as it can coagulate the heat-resistant polymer, but is preferably water or an organic solvent used for the coating liquid mixed with an appropriate amount of water. Here, the mixing amount of water is preferably 40 to 80% by weight with respect to the coagulation liquid. When the amount of water is less than 40% by weight, there arises a problem that the time required for coagulating the heat-resistant polymer becomes long or the coagulation becomes insufficient. On the other hand, when the amount is more than 80% by weight, there arises a problem that the cost for solvent recovery becomes high, or the surface that comes into contact with the coagulating liquid is solidified too quickly and the surface is not sufficiently porous.
工程(iv)は、工程(iii)に引き続き、得られたセパレータから水洗で凝固液を除去し、次いで乾燥する工程である。乾燥方法は特に限定されないが、乾燥温度は50〜80℃が適当であり、高い乾燥温度を適用する場合は、熱収縮による寸法変化が起こらないようにするためにロールに接触させるような方法を適用することが好ましい。 Step (iv) is a step of removing the coagulating liquid from the obtained separator by washing with water, and then drying, following step (iii). The drying method is not particularly limited, but a drying temperature of 50 to 80 ° C. is appropriate. When a high drying temperature is applied, a method of contacting with a roll in order to prevent a dimensional change due to heat shrinkage occurs. It is preferable to apply.
[非水電解質電池]
非水電解質電池セパレータが、前記のような熱可塑性樹脂を主として形成された微多孔膜等の基材と、その片面又は両面に積層された前記のような耐熱性高分子を主として形成された耐熱性多孔質層とからなるものである限り、本発明の非水電解質電池セパレータは、公知のいかなる構成の非水電解質電池にも適用することができ、安全性に優れた電池が得られる。適用される非水電解質電池は一次電池であっても二次電池であっても良く、その種類や構成は、何ら限定されるものではないが、本発明の非水電解質電池セパレータは、リチウムのドープ・脱ドープにより起電力を得る非水電解質二次電池に好適に応用することができる。中でも、リチウムイオン二次電池への適用が好ましい。
[Nonaqueous electrolyte battery]
A non-aqueous electrolyte battery separator is mainly formed of a base material such as a microporous membrane mainly formed of the thermoplastic resin as described above and a heat-resistant polymer as described above laminated on one or both sides thereof. As long as it consists of a porous layer, the nonaqueous electrolyte battery separator of the present invention can be applied to any known nonaqueous electrolyte battery, and a battery with excellent safety can be obtained. The applied nonaqueous electrolyte battery may be a primary battery or a secondary battery, and the type and configuration of the nonaqueous electrolyte battery are not limited in any way. It can be suitably applied to a non-aqueous electrolyte secondary battery that obtains an electromotive force by doping and dedoping. Among these, application to a lithium ion secondary battery is preferable.
一般に非水電解質二次電池とは、負極と正極がセパレータを介して対向している電池要素に電解液が含浸され、これが外装に封入された構造となっているものをいう。負極は、負極活物質、導電助剤、バインダーからなる負極合剤が集電体(銅箔、ステンレス箔、ニッケル箔等)上に成形された構造となっている。負極活物質としては、リチウムを電気化学的にドープすることが可能な材料、例えば、炭素材料、シリコン、アルミニウム、スズかが用いられる。正極は、正極活物質、導電助剤、バインダーからなる正極合剤が集電体上に成形された構造となっている。正極活物質としては、リチウム含有遷移金属酸化物、例えば、LiCoO2、LiNiO2、LiMn0.5Ni0.5O2、LiCo1/3Ni1/3Mn1/3O2、LiMn2O4、LiFePO4が用いられる。電解液は、リチウム塩、例えば、LiPF6、LiBF4、LiClO4を非水系溶媒に溶解した構成である。非水系溶媒としては、プロピレンカーボネート、エチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、γ−ブチロラクトン、ビニレンカーボネートなどが挙げられる。外装材は金属缶またはアルミラミネートパック等が挙げられる。電池の形状は角型、円筒型、コイン型などがあるが、本発明のセパレータはいずれの形状においても好適に適用することが可能である。 In general, a nonaqueous electrolyte secondary battery refers to a battery element in which a battery element in which a negative electrode and a positive electrode face each other with a separator interposed therebetween is impregnated with an electrolytic solution and sealed in an exterior. The negative electrode has a structure in which a negative electrode mixture composed of a negative electrode active material, a conductive additive, and a binder is formed on a current collector (copper foil, stainless steel foil, nickel foil, etc.). As the negative electrode active material, a material capable of electrochemically doping lithium, for example, a carbon material, silicon, aluminum, or tin is used. The positive electrode has a structure in which a positive electrode mixture composed of a positive electrode active material, a conductive additive, and a binder is formed on a current collector. Examples of the positive electrode active material include lithium-containing transition metal oxides such as LiCoO 2 , LiNiO 2 , LiMn 0.5 Ni 0.5 O 2 , LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiMn 2 O. 4 and LiFePO 4 are used. The electrolytic solution has a configuration in which a lithium salt, for example, LiPF 6 , LiBF 4 , or LiClO 4 is dissolved in a non-aqueous solvent. Examples of the non-aqueous solvent include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, and vinylene carbonate. Examples of the exterior material include a metal can or an aluminum laminate pack. The shape of the battery includes a square shape, a cylindrical shape, a coin shape, and the like, but the separator of the present invention can be suitably applied to any shape.
以下、実施例により本発明を詳述する。なお、本発明における各種の測定方法は、以下の通りである。 Hereinafter, the present invention will be described in detail by way of examples. Various measurement methods in the present invention are as follows.
[分子量と分子量分布の測定方法]
DMFにLiClを0.01モル/L溶解させた溶液にポリマーを1重量%溶解し、これを測定サンプルとしてGPC測定を実施し、分子量および分子量分布を算出した。測定には島津クロマトパックC−R4A、GPCカラム(昭和電工社製、GPC・KD−802)を用い、検出波長280nmで測定した。リファレンスは、ポリスチレン分子量標準物質を用いた。なお、PE微多孔膜とm−アラミドが複合化された状態のセパレータについて、m−アラミドの分子量分布を測定する方法としては、先ずセパレータ1gをサンプリングし、LiClを0.01モル/L溶解させたDMF20gを加えて、80℃でm−アラミドだけを溶解させ測定サンプルとした。耐熱性高分子中における分子量8.0×103以下の低分子量ポリマーの含有量(重量%)は、図1に示すように、GPC曲線を分子量0から8.0×103までの区間で積分した値S1を、GPC曲線を分子量0から1.0×106までの区間で積分した値S2で割って、これに100を乗じて求めた。また、ここでいう分子量分布(MWD)はGPCで求められる重量平均分子量(Mw)と数平均分子量(Mn)との比で表わされ、以下の数式(式1)で求められる値である。なお、重量平均分子量(Mw)および数平均分子量(Mn)は、分子量0から1.0×106までの全区間において計算したものである。
MWD=Mw/Mn (式1)
[Measurement method of molecular weight and molecular weight distribution]
A polymer was dissolved by 1% by weight in a solution obtained by dissolving 0.01 mol / L of LiCl in DMF, and GPC measurement was carried out using this as a measurement sample to calculate the molecular weight and molecular weight distribution. For the measurement, Shimadzu Chromatopack C-R4A and a GPC column (GPC / KD-802, manufactured by Showa Denko KK) were used and measured at a detection wavelength of 280 nm. As a reference, a polystyrene molecular weight standard was used. For the separator in which PE microporous membrane and m-aramid are combined, the method for measuring the molecular weight distribution of m-aramid is to first sample 1 g of the separator and dissolve LiCl in 0.01 mol / L. DMF (20 g) was added, and only m-aramid was dissolved at 80 ° C. to prepare a measurement sample. The content (% by weight) of the low molecular weight polymer having a molecular weight of 8.0 × 10 3 or less in the heat-resistant polymer is shown in FIG. 1 in the GPC curve in the interval from
MWD = Mw / Mn (Formula 1)
[膜厚]
接触式の膜厚計(ミツトヨ社製)にて20点測定し、これを平均することで求めた。ここで接触端子は底面が直径0.5cmの円柱状のものを用い、接触端子に1.2kg/cm2の荷重が印加されるような条件で測定した。
[Film thickness]
It was determined by measuring 20 points with a contact-type film thickness meter (manufactured by Mitutoyo Co., Ltd.) and averaging them. Here, the contact terminal used was a cylindrical one having a bottom surface of 0.5 cm in diameter, and measurement was performed under a condition that a load of 1.2 kg / cm 2 was applied to the contact terminal.
[空孔率]
構成材料がa、b、c…、nからなり、構成材料の重量がWa、Wb、Wc…、Wn(g/cm2)であり、それぞれの真密度がda、db、dc…、dn(g/cm3)で、着目する層の膜厚をt(cm)としたとき、空孔率ε(%)は以下の数式(式2)より求めた。
ε={1−(Wa/da+Wb/db+Wc/dc+…+Wn/dn)/t}×100 …(式2)
[Porosity]
Construction materials a, b, c ..., consist n, weight Wa of the constituent materials, Wb, Wc ..., a Wn (g / cm 2), each true density da, db, dc ..., dn ( g / cm 3 ), where the film thickness of the layer of interest is t (cm), the porosity ε (%) was obtained from the following equation (Equation 2).
ε = {1− (Wa / da + Wb / db + Wc / dc +... + Wn / dn) / t} × 100 (Expression 2)
[突刺強度]
カトーテック社製KES−G5ハンディー圧縮試験器を用いて、針先端の曲率半径0.5mm、突刺速度2mm/secの条件で突刺試験を行い、最大突刺荷重を突刺強度とした。ここでサンプルはΦ11.3mmの穴があいた金枠(試料ホルダー)にシリコンゴム製のパッキンも一緒に挟み固定した。
[Puncture strength]
Using a KES-G5 handy compression tester manufactured by Kato Tech Co., Ltd., a piercing test was conducted under the conditions of a radius of curvature of the needle tip of 0.5 mm and a piercing speed of 2 mm / sec, and the maximum piercing load was defined as the piercing strength. Here, the sample was fixed by sandwiching a silicon rubber packing in a metal frame (sample holder) having a hole of Φ11.3 mm.
[無機フィラーの平均粒子径]
レーザー回折式粒度分布測定装置(シスメックス社製、マスターサイザー2000)を用いて測定を行った。分散媒としては水を用い、分散剤として非イオン性界面活性剤Triton・X−100を微量用いた。体積粒度分布における中心粒子径(D50)を平均粒子径とした。
[Average particle size of inorganic filler]
Measurement was performed using a laser diffraction particle size distribution analyzer (manufactured by Sysmex Corporation, Mastersizer 2000). Water was used as a dispersion medium, and a small amount of a nonionic surfactant Triton · X-100 was used as a dispersant. The central particle size (D50) in the volume particle size distribution was taken as the average particle size.
[実施例1]
1)ポリメタフェニレンイソフタルアミドの製造
温度計、撹拌装置及び原料投入口を備えた反応容器に、水分率が100ppm以下のNMP753gを入れ、このNMP中にメタフェニレンジアミン85.5gを入れ、0℃に冷却した。この冷却したジアミン溶液にイソフタル酸クロライド160.5gを撹拌しながら徐々に添加し反応させた。この反応で溶液の温度は70℃に上昇した。粘度変化が止まった後、水酸化カルシウム粉末を58.4g添加し、さらに40分間撹拌して反応を終了させて重合溶液を取り出し、水中で再沈殿させポリメタフェニレンイソフタルアミドを184.0g得た。このものの分子量分布Mw/Mnは4で、重量平均分子量Mwは1.0×105で、分子量8000以下の低分子量体の含有量は0.8重量%であった。
[Example 1]
1) Production of polymetaphenylene isophthalamide In a reaction vessel equipped with a thermometer, a stirrer, and a raw material inlet, 753 g of NMP having a moisture content of 100 ppm or less was placed, and 85.5 g of metaphenylenediamine was placed in this NMP, and the temperature was 0 ° C. Cooled to. To this cooled diamine solution, 160.5 g of isophthalic acid chloride was gradually added with stirring to react. This reaction increased the temperature of the solution to 70 ° C. After the change in viscosity stopped, 58.4 g of calcium hydroxide powder was added and stirred for another 40 minutes to complete the reaction, and the polymerization solution was taken out and reprecipitated in water to obtain 184.0 g of polymetaphenylene isophthalamide. . The molecular weight distribution Mw / Mn of this product was 4, the weight average molecular weight Mw was 1.0 × 10 5 , and the content of low molecular weight compounds having a molecular weight of 8000 or less was 0.8% by weight.
2)ポリエチレン多孔膜の製造
ポリエチレンパウダーとして、Ticona社製のGUR2126(重量平均分子量415万、融点141℃)とGURX143(重量平均分子量56万、融点135℃)を用いた。GUR2126とGURX143を、1:9(重量比)となるようにして、ポリエチレン濃度が30重量%となるように流動パラフィン(松村石油研究所社製;スモイルP−350P;沸点480℃)とデカリンの混合溶媒中に溶解させ、ポリエチレン溶液を作製した。このポリエチレン溶液の組成は、ポリエチレン:流動パラフィン:デカリン=30:45:25(重量比)であった。
2) Manufacture of a polyethylene porous membrane As polyethylene powder, GUR2126 (weight average molecular weight 4150,000, melting | fusing point 141 degreeC) and GURX143 (weight average molecular weight 560,000, melting | fusing point 135 degreeC) by a Ticona company were used. GUR2126 and GURX143 are made to be 1: 9 (weight ratio), and liquid paraffin (manufactured by Matsumura Oil Research Co., Ltd .; Smoyl P-350P; boiling point 480 ° C.) and decalin so that the polyethylene concentration becomes 30% by weight. A polyethylene solution was prepared by dissolving in a mixed solvent. The composition of this polyethylene solution was polyethylene: liquid paraffin: decalin = 30: 45: 25 (weight ratio).
このポリエチレン溶液を148℃でダイから押し出し、水浴中で冷却してゲル状テープ(ベーステープ)を作製した。このベーステープを60℃で8分、95℃で15分乾燥し、次いで、ベーステープを縦延伸、横延伸と逐次行う2軸延伸にて延伸した。ここで、縦延伸は5.5倍、延伸温度は90℃、横延伸は延伸倍率11.0倍、延伸温度は105℃とした。横延伸の後に125℃で熱固定を行った。次にこれを塩化メチレン浴に浸漬し、流動パラフィンとデカリンを抽出した。その後、50℃で乾燥し、120℃でアニール処理しポリエチレン微多孔膜を得た。膜厚は12μm、空孔率37%、ガーレ値301sec/100cc、膜抵抗2.6ohm・cm2であった。 This polyethylene solution was extruded from a die at 148 ° C. and cooled in a water bath to prepare a gel tape (base tape). The base tape was dried at 60 ° C. for 8 minutes and at 95 ° C. for 15 minutes, and then the base tape was stretched by biaxial stretching that was performed in the order of longitudinal stretching and lateral stretching. Here, the longitudinal stretching was 5.5 times, the stretching temperature was 90 ° C., the transverse stretching was 11.0 times the stretching ratio, and the stretching temperature was 105 ° C. After transverse stretching, heat setting was performed at 125 ° C. Next, this was immersed in a methylene chloride bath to extract liquid paraffin and decalin. Then, it dried at 50 degreeC and annealed at 120 degreeC, and obtained the polyethylene microporous film. The film thickness was 12 μm, the porosity was 37%, the Gurley value was 301 sec / 100 cc, and the film resistance was 2.6 ohm · cm 2 .
3)非水電解質電池セパレータの製造
前記で得られたポリメタフェニレンイソフタルアミドとポリエチレン多孔膜を用い、そして、これに無機フィラーを併用して、本発明の非水電解質電池セパレータを製造した。
具体的には、ポリメタフェニレンイソフタルアミドと平均粒子径0.8μmの水酸化アルミニウム(昭和電工社製;H−43M)からなる無機フィラーとが、重量比で25:75となるように調整し、これらをポリメタフェニレンイソフタルアミド濃度が5.5重量%となるように、ジメチルアセトアミド(DMAc)とトリプロピレングリコール(TPG)が重量比50:50となっている混合溶媒に混合し、塗工用スラリーを得た。
3) Production of Nonaqueous Electrolyte Battery Separator The polymetaphenylene isophthalamide obtained above and a polyethylene porous membrane were used, and an inorganic filler was used in combination with this to produce the nonaqueous electrolyte battery separator of the present invention.
Specifically, the inorganic filler made of polymetaphenylene isophthalamide and aluminum hydroxide having an average particle size of 0.8 μm (made by Showa Denko KK; H-43M) is adjusted to a weight ratio of 25:75. These were mixed in a mixed solvent of dimethylacetamide (DMAc) and tripropylene glycol (TPG) in a weight ratio of 50:50 so that the polymetaphenylene isophthalamide concentration was 5.5% by weight. A slurry was obtained.
一対のマイヤーバー(番手#6)を、20μmのクリアランスで対峙させた。マイヤーバーに、上記塗工用スラリーを適量のせ、一対のマイヤーバー間にポリエチレン微多孔膜を通して、ポリエチレン微多孔膜の両面に塗工用スラリーを塗工した。そして、塗工されたものを、重量比で水:DMAc:TPG=50:25:25で40℃となっている凝固液中に浸漬した。次いで水洗・乾燥を行い、ポリエチレン微多孔膜の両面(表裏面)にポリメタフェニレンイソフタルアミドからなる耐熱性多孔質層を形成し、本発明の非水電解質電池セパレータを得た。 A pair of Meyer bars (count # 6) was opposed to each other with a clearance of 20 μm. An appropriate amount of the above slurry for coating was placed on a Mayer bar, a polyethylene microporous membrane was passed between a pair of Mayer bars, and the coating slurry was coated on both sides of the polyethylene microporous membrane. And what was coated was immersed in the coagulating liquid which is 40 degreeC by water: DMAc: TPG = 50: 25: 25 by weight ratio. Next, washing with water and drying were performed to form a heat-resistant porous layer made of polymetaphenylene isophthalamide on both surfaces (front and back surfaces) of the polyethylene microporous membrane, thereby obtaining the nonaqueous electrolyte battery separator of the present invention.
得られた非水電解質電池セパレータの特性を分析したところ、耐熱性多孔質層の空孔率が70%、セパレータ全体の平均膜厚が20μmであった。当該セパレータの突刺強度は430gであり、非常に優れた強度を有することが分かった。なお、得られたセパレータについてポリメタフェニレンイソフタルアミドのGPC測定を実施したところ、低分子量体の含有量、分子量分布Mw/Mnおよび重量平均分子量Mwは塗布前のポリマーと同等であった。 When the characteristics of the obtained nonaqueous electrolyte battery separator were analyzed, the porosity of the heat-resistant porous layer was 70%, and the average thickness of the entire separator was 20 μm. The separator had a puncture strength of 430 g and was found to have a very excellent strength. In addition, when the GPC measurement of polymetaphenylene isophthalamide was implemented about the obtained separator, content of a low molecular weight body, molecular weight distribution Mw / Mn, and the weight average molecular weight Mw were equivalent to the polymer before application | coating.
[実施例2]
メタフェニレンジアミンを85.2g用いたこと以外は、実施例1と同様にしてポリメタフェニレンイソフタルアミドを製造した。このものの分子量分布Mw/Mnは4.5で、重量平均分子量Mwは1.1×105で、分子量8000以下の低分子量体の含有量は0.8重量%であり、ポリマー収量は184.0gであった。
[Example 2]
Polymetaphenylene isophthalamide was produced in the same manner as in Example 1 except that 85.2 g of metaphenylenediamine was used. The molecular weight distribution Mw / Mn of this product is 4.5, the weight average molecular weight Mw is 1.1 × 10 5 , the content of low molecular weight molecules having a molecular weight of 8000 or less is 0.8% by weight, and the polymer yield is 184. It was 0 g.
これを用いて実施例1の場合と同様にして、本発明の非水電解質電池セパレータを得た。得られた非水電解質電池セパレータの特性を分析したところ、耐熱性多孔質層の空孔率が70%、セパレータ全体の平均膜厚が20μmであった。当該セパレータの突刺強度は430gであり、非常に優れた強度を有することが分かった。なお、得られたセパレータについてポリメタフェニレンイソフタルアミドのGPC測定を実施したところ、低分子量体の含有量、分子量分布Mw/Mnおよび重量平均分子量Mwは塗布前のポリマーと同等であった。
以上の結果を表1にまとめて示す。
Using this, a nonaqueous electrolyte battery separator of the present invention was obtained in the same manner as in Example 1. When the characteristics of the obtained nonaqueous electrolyte battery separator were analyzed, the porosity of the heat-resistant porous layer was 70%, and the average thickness of the entire separator was 20 μm. The separator had a puncture strength of 430 g and was found to have a very excellent strength. In addition, when the GPC measurement of polymetaphenylene isophthalamide was implemented about the obtained separator, content of a low molecular weight body, molecular weight distribution Mw / Mn, and the weight average molecular weight Mw were equivalent to the polymer before application | coating.
The above results are summarized in Table 1.
Claims (12)
前記耐熱性高分子の分子量分布Mw/Mnが、1<Mw/Mn<5であり、且つ、前記耐熱性高分子の重量平均分子量Mwが、8.0×103以上1.0×106以下である
ことを特徴とする非水電解質電池セパレータ。 A base material mainly formed of a thermoplastic resin and having pores or voids therein and having a shutdown function, and a heat-resistant porous layer mainly formed of a heat-resistant polymer and laminated on one or both surfaces of the base material A non-aqueous electrolyte battery separator comprising:
The molecular weight distribution Mw / Mn of the heat resistant polymer is 1 <Mw / Mn <5, and the weight average molecular weight Mw of the heat resistant polymer is 8.0 × 10 3 or more and 1.0 × 10 6. The nonaqueous electrolyte battery separator characterized by the following.
ことを特徴とする請求項1記載の非水電解質電池セパレータ。 The non-aqueous electrolyte battery separator according to claim 1, wherein the heat-resistant polymer has a content of a low molecular weight polymer having a molecular weight of 8.0 × 10 3 or less of less than 1% by weight.
ことを特徴とする請求項1又は2記載の非水電解質電池セパレータ。 The nonaqueous electrolyte battery separator according to claim 1 or 2, wherein the nonaqueous electrolyte battery separator has a puncture strength of 100 to 2000 g.
ことを特徴とする請求項1〜3のいずれか1項記載の非水電解質電池セパレータ。 The nonaqueous electrolyte battery separator according to any one of claims 1 to 3, wherein the heat-resistant porous layer contains an inorganic filler in a weight fraction of 50 wt% or more and 95 wt% or less.
ことを特徴とする請求項4記載の非水電解質電池セパレータ。 The non-aqueous electrolyte battery separator according to claim 4, wherein the inorganic filler is mainly composed of a metal hydroxide.
ことを特徴とする請求項1〜5のいずれか1項記載の非水電解質電池セパレータ。 The heat-resistant polymer is one or more selected from the group consisting of aromatic polyamide, polyimide, polyethersulfone, polysulfone, polyetherketone, and polyetherimide. The nonaqueous electrolyte battery separator according to any one of the above.
ことを特徴とする請求項6記載の非水電解質電池セパレータ。 The aromatic polyamide is produced by polymerizing an aromatic dicarboxylic acid halide and an aromatic diamine in an organic polar solvent which is a good solvent for the polyamide to be produced. Non-aqueous electrolyte battery separator.
ことを特徴とする請求項1〜7のいずれか1項記載の非水電解質電池セパレータ。 The non-aqueous electrolyte battery separator according to any one of claims 1 to 7, wherein the base material is a microporous film made of a thermoplastic resin mainly composed of polyolefin.
ことを特徴とする請求項1〜8のいずれか1項記載の非水電解質電池セパレータ。 The nonaqueous electrolyte battery separator according to any one of claims 1 to 8, wherein the nonaqueous electrolyte battery separator is a separator for a lithium ion secondary battery.
(i)芳香族ジカルボン酸ハライドと芳香族ジアミンを、生成するポリアミドに対し良溶媒である有機溶媒中で反応せしめて、分子量分布Mw/Mnが1<Mw/Mn<5であり、且つ、重量平均分子量Mwが8.0×103以上1.0×106以下である芳香族ポリアミドを製造する工程と、
(ii)得られた芳香族ポリアミドの水溶性有機溶剤溶液を、前記基材の片面又は両面に塗工する工程と、
(iii)塗工された前記基材を水又は水と前記有機溶剤の混合液からなる凝固液中に浸漬して芳香族ポリアミドを凝固させる工程と、
(iv)この凝固工程後の前記基材を水洗し乾燥する工程と、を実施する
ことを特徴とする非水電解質電池セパレータの製造方法。 A base material mainly formed of thermoplastic resin and having a pore or void inside and having a shutdown function, and a heat-resistant porous layer mainly formed of aromatic polyamide and laminated on one or both surfaces of the base material; A method for producing a non-aqueous electrolyte battery separator according to claim 1, comprising:
(I) An aromatic dicarboxylic acid halide and an aromatic diamine are reacted in an organic solvent, which is a good solvent, with respect to the resulting polyamide, the molecular weight distribution Mw / Mn is 1 <Mw / Mn <5, and the weight A step of producing an aromatic polyamide having an average molecular weight Mw of 8.0 × 10 3 or more and 1.0 × 10 6 or less;
(Ii) coating the obtained water-soluble organic solvent solution of aromatic polyamide on one or both sides of the substrate;
(Iii) a step of solidifying the aromatic polyamide by immersing the coated substrate in water or a coagulating liquid composed of water and the organic solvent;
(Iv) A step of washing the substrate after the coagulation step and drying the substrate. A method for producing a non-aqueous electrolyte battery separator.
(i)メタ型芳香族ジカルボン酸ハライドとメタ型芳香族ジアミンを、生成するポリアミドに対し良溶媒でない有機溶媒中で反応せしめて溶液若しくは分散液を作り、これを酸受容剤の水溶液と接触させ反応を完結せしめて、分子量分布Mw/Mnが1<Mw/Mn<5であり、且つ、重量平均分子量Mwが8.0×103以上1.0×106以下であるメタ型芳香族ポリアミドを製造する工程と、
(ii)得られたメタ型芳香族ポリアミドの水溶性有機溶剤溶液を、前記基材の片面又は両面に塗工する工程と、
(iii)塗工された前記基材を、水又は水と前記有機溶剤の混合液からなる凝固液中に浸漬して、メタ型芳香族ポリアミドを凝固させる工程と、
(iv)この凝固工程後の前記基材を水洗し乾燥する工程と、を実施する
ことを特徴とする非水電解質電池セパレータの製造方法。 A base material mainly formed of thermoplastic resin and having a shutdown function and having pores or voids inside, and a shutdown function, and mainly formed of a meta-type aromatic polyamide and laminated on one or both sides of the base material It is a manufacturing method of the nonaqueous electrolyte battery separator according to claim 1 provided with a heat resistant porous layer,
(I) A meta-type aromatic dicarboxylic acid halide and a meta-type aromatic diamine are reacted in an organic solvent that is not a good solvent for the resulting polyamide to form a solution or dispersion, which is brought into contact with an acid acceptor aqueous solution. Meta-type aromatic polyamide having a molecular weight distribution Mw / Mn of 1 <Mw / Mn <5 and a weight average molecular weight Mw of 8.0 × 10 3 or more and 1.0 × 10 6 or less by completing the reaction Manufacturing process,
(Ii) coating the obtained water-soluble organic solvent solution of the meta-type aromatic polyamide on one or both surfaces of the substrate;
(Iii) a step of solidifying the meta-aromatic polyamide by immersing the coated base material in a coagulation liquid composed of water or a mixture of water and the organic solvent;
(Iv) A step of washing the substrate after the coagulation step and drying the substrate. A method for producing a non-aqueous electrolyte battery separator.
ことを特徴とする非水電解質二次電池。 A non-aqueous electrolyte secondary battery that obtains an electromotive force by doping and dedoping of lithium, wherein the non-aqueous electrolyte battery separator according to any one of claims 1 to 9 is used. Next battery.
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