WO2021193205A1 - リチウムイオン電池用自己消火性フィルム及びその製造方法、並びに、リチウムイオン電池 - Google Patents
リチウムイオン電池用自己消火性フィルム及びその製造方法、並びに、リチウムイオン電池 Download PDFInfo
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- WO2021193205A1 WO2021193205A1 PCT/JP2021/010443 JP2021010443W WO2021193205A1 WO 2021193205 A1 WO2021193205 A1 WO 2021193205A1 JP 2021010443 W JP2021010443 W JP 2021010443W WO 2021193205 A1 WO2021193205 A1 WO 2021193205A1
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- Prior art keywords
- self
- ion battery
- lithium ion
- heat
- film
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 143
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 143
- 238000004519 manufacturing process Methods 0.000 title claims description 21
- 239000002245 particle Substances 0.000 claims abstract description 182
- 239000000463 material Substances 0.000 claims abstract description 20
- 239000011230 binding agent Substances 0.000 claims description 114
- 239000010410 layer Substances 0.000 claims description 98
- 239000003795 chemical substances by application Substances 0.000 claims description 71
- 239000006185 dispersion Substances 0.000 claims description 31
- 239000012790 adhesive layer Substances 0.000 claims description 13
- 229920005989 resin Polymers 0.000 claims description 13
- 239000011347 resin Substances 0.000 claims description 13
- 239000011248 coating agent Substances 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 11
- 229920000098 polyolefin Polymers 0.000 claims description 11
- 238000002844 melting Methods 0.000 claims description 9
- 230000008018 melting Effects 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000000155 melt Substances 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 3
- 238000002485 combustion reaction Methods 0.000 description 14
- -1 polyethylene Polymers 0.000 description 14
- 230000000694 effects Effects 0.000 description 13
- 239000000853 adhesive Substances 0.000 description 10
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 239000008151 electrolyte solution Substances 0.000 description 7
- 229910052744 lithium Inorganic materials 0.000 description 7
- 239000007784 solid electrolyte Substances 0.000 description 7
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 6
- 239000004734 Polyphenylene sulfide Substances 0.000 description 6
- 239000004743 Polypropylene Substances 0.000 description 6
- 230000002159 abnormal effect Effects 0.000 description 6
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 6
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- 230000002776 aggregation Effects 0.000 description 4
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
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- 239000007774 positive electrode material Substances 0.000 description 4
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- 239000004698 Polyethylene Substances 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
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- 229910052782 aluminium Inorganic materials 0.000 description 3
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- 229920001577 copolymer Polymers 0.000 description 3
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
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- XHXFXVLFKHQFAL-UHFFFAOYSA-N phosphoryl trichloride Chemical compound ClP(Cl)(Cl)=O XHXFXVLFKHQFAL-UHFFFAOYSA-N 0.000 description 3
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- 229920002125 Sokalan® Polymers 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 2
- 239000011267 electrode slurry Substances 0.000 description 2
- JHXRVOAOESLJHL-UHFFFAOYSA-N ethene;1,2,3,4,5-pentabromobenzene Chemical compound C=C.BrC1=CC(Br)=C(Br)C(Br)=C1Br.BrC1=CC(Br)=C(Br)C(Br)=C1Br JHXRVOAOESLJHL-UHFFFAOYSA-N 0.000 description 2
- 229910003480 inorganic solid Inorganic materials 0.000 description 2
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- YUAPUIKGYCAHGM-UHFFFAOYSA-N 1,2-dibromo-3-(2,3-dibromopropoxy)propane Chemical compound BrCC(Br)COCC(Br)CBr YUAPUIKGYCAHGM-UHFFFAOYSA-N 0.000 description 1
- CWZVMVIHYSYLSI-UHFFFAOYSA-N 1,3-dibromo-5-[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfonyl-2-(2,3-dibromopropoxy)benzene Chemical compound C1=C(Br)C(OCC(Br)CBr)=C(Br)C=C1S(=O)(=O)C1=CC(Br)=C(OCC(Br)CBr)C(Br)=C1 CWZVMVIHYSYLSI-UHFFFAOYSA-N 0.000 description 1
- 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 1
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 229920003043 Cellulose fiber Polymers 0.000 description 1
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- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910018133 Li 2 S-SiS 2 Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910010833 LiI-Li2S-SiS2 Inorganic materials 0.000 description 1
- 229910010855 LiI—Li2S—SiS2 Inorganic materials 0.000 description 1
- 229910010847 LiI—Li3PO4-P2S5 Inorganic materials 0.000 description 1
- 229910010864 LiI—Li3PO4—P2S5 Inorganic materials 0.000 description 1
- 229910013131 LiN Inorganic materials 0.000 description 1
- 229910013528 LiN(SO2 CF3)2 Inorganic materials 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000003522 acrylic cement Substances 0.000 description 1
- 239000000443 aerosol Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 1
- CEDDGDWODCGBFQ-UHFFFAOYSA-N carbamimidoylazanium;hydron;phosphate Chemical compound NC(N)=N.OP(O)(O)=O CEDDGDWODCGBFQ-UHFFFAOYSA-N 0.000 description 1
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- 238000000354 decomposition reaction Methods 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 229920006332 epoxy adhesive Polymers 0.000 description 1
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 1
- VXNZUUAINFGPBY-UHFFFAOYSA-N ethyl ethylene Natural products CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
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- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
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- 150000002513 isocyanates Chemical class 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- URIIGZKXFBNRAU-UHFFFAOYSA-N lithium;oxonickel Chemical compound [Li].[Ni]=O URIIGZKXFBNRAU-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical group OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
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- 238000000691 measurement method Methods 0.000 description 1
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 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
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
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- 238000012545 processing Methods 0.000 description 1
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- 229910052710 silicon Inorganic materials 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
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- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
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Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present disclosure relates to a self-extinguishing film for a lithium ion battery, a method for manufacturing the same, and a lithium ion battery.
- Lithium-ion batteries are used in various applications such as mobile phones, notebook computers, electric vehicles, and large storage batteries for power sources. Lithium-ion batteries are required to have higher capacity, higher energy density, higher voltage, etc. from the viewpoint of longer power supply time and the need to increase output.
- various studies have been made on the safety of batteries typified by lithium-ion batteries, that is, on the ignition suppression and fire extinguishing of the batteries.
- Patent Document 1 states that even if the inside of a battery becomes hot due to an abnormal operating state of the battery, the battery can be prevented from igniting or the fire can be extinguished at the time of ignition.
- the improved secondary battery pouch includes an electrode assembly including a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode, the electrode assembly is housed in the internal pouch, and the electrode leads are pulled out from the internal pouch.
- the internal pouch is housed in the external pouch, the electrode leads are pulled out from the external pouch, and the space between the internal pouch and the external pouch contains a safety member. Batteries are disclosed. Further, in Patent Document 2, a negative electrode, a separator and a positive electrode are laminated as an electrochemical device capable of suppressing a fire caused by ignition of lithium by initial fire extinguishing while ensuring miniaturization and weight reduction of the entire power storage device.
- Electrode laminate an electrolytic solution containing a fire extinguishing agent that burns to generate an aerosol when a predetermined temperature is reached, a lithium ion-containing electrolyte, and an organic solvent, and an electrolytic solution for immersing the electrode laminate and the fire extinguishing agent.
- an electrochemical device including the electrode laminate, the fire extinguishing agent, and the exterior body containing the electrolytic solution are disclosed.
- Patent Document 1 Japanese Patent Application Laid-Open No. 2018-514608
- Patent Document 2 Japanese Patent No. 6431147
- An object of the present disclosure is to provide a self-extinguishing film for a lithium ion battery capable of suppressing combustion of a lithium ion battery element at an early stage, a method for producing the same, and a lithium ion battery including the self-extinguishing film for a lithium ion battery. Is.
- a self-extinguishing film for a lithium ion battery comprising a self-extinguishing layer containing a heat-meltable binder and fire extinguishing agent particles.
- the number average particle diameter of the heat-meltable binder particles is 0.1 ⁇ m to 6.0 ⁇ m.
- ⁇ 4> The self-extinguishing film for a lithium ion battery according to ⁇ 2> or ⁇ 3>, wherein the number average particle diameter of the heat-meltable binder particles is 0.2 ⁇ m to 2.5 ⁇ m.
- ⁇ 5> The lithium ion battery according to any one of ⁇ 2> to ⁇ 4>, wherein the heat-meltable binder particles have an average circularity of 0.80 or more calculated by the following formula (1).
- Average circularity (perimeter of a circle with the same area as the projected particle area / perimeter of the projected particle image) ... Equation (1)
- the heat-meltable binder is a resin.
- the resin conforms to JIS K7210-1995 and has a melt flow rate of 20 g / 10 minutes to 55 g / 10 minutes measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N.
- ⁇ 7> The self-extinguishing film for a lithium ion battery according to any one of ⁇ 1> to ⁇ 6>, wherein the heat-meltable binder contains polyolefin.
- ⁇ 10> Furthermore An adhesive layer arranged on one surface side of the self-extinguishing layer and A flame-resistant layer arranged on the other surface side of the self-extinguishing layer, To prepare The self-extinguishing film for a lithium ion battery according to any one of ⁇ 1> to ⁇ 8>.
- the number of agglomerates of the fire extinguishing agent particles having a diameter of 0.5 mm or more is 10 or less in terms of the number of agglomerates per square region having a side of 10 cm.
- ⁇ 12> The method for producing a self-extinguishing film for a lithium ion battery according to any one of ⁇ 1> to ⁇ 11>.
- the aqueous dispersion of the heat-meltable binder particles which are particles made of the heat-meltable binder, and the aqueous dispersion of the fire extinguishing agent particles are mixed.
- the pH of the aqueous dispersion of the heat-meltable binder particles is 8.0 to 11.0.
- ⁇ 14> A positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and the like.
- Lithium-ion battery elements including The self-extinguishing film for a lithium ion battery according to any one of ⁇ 1> to ⁇ 11>.
- Lithium-ion battery with. ⁇ 15> With at least a part of the lithium ion battery element, With at least a part of the self-extinguishing film for lithium-ion batteries The lithium ion battery according to ⁇ 14>, wherein the lithium ion battery is adhered to.
- a self-extinguishing film for a lithium ion battery capable of suppressing combustion of a lithium ion battery element at an early stage, a method for producing the same, and a lithium ion battery including the self-extinguishing film for a lithium ion battery are provided. ..
- FIG. 2 is a cross-sectional view taken along the line II-II of the lithium ion battery shown in FIG. It is a graph which shows the result of the nail piercing test of the lithium ion battery of Example 1. It is a graph which shows the result of the nail piercing test of the lithium ion battery of the comparative example 1.
- FIG. 2 is a cross-sectional view taken along the line II-II of the lithium ion battery shown in FIG. It is a graph which shows the result of the nail piercing test of the lithium ion battery of Example 1. It is a graph which shows the result of the nail piercing test of the lithium ion battery of the comparative example 1.
- the numerical range represented by using “-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
- the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. means.
- the self-extinguishing film for a lithium ion battery of the present disclosure includes a self-extinguishing layer containing a heat-meltable binder and fire extinguishing agent particles.
- the self-extinguishing film of the present disclosure is used together with a lithium ion battery element. At this time, when abnormal heat generation occurs in the lithium ion battery element, combustion of the lithium ion battery element can be suppressed at an early stage.
- the self-fire extinguishing layer in the self-extinguishing film of the present disclosure contains a heat-meltable binder together with the fire extinguishing agent particles.
- abnormal heat generation of the lithium ion battery element occurs, and when the self-fire extinguishing layer reaches a certain temperature due to the action of this heat, the heat-meltable binder in the self-fire extinguishing layer melts, whereby self It is considered that the fire extinguishing agent particles are released from the fire extinguishing layer. It is considered that the released fire extinguishing agent particles have an effect of suppressing the combustion of the lithium ion battery element at an early stage.
- FIG. 1 is a schematic cross-sectional view showing an embodiment of a self-extinguishing film for a lithium ion battery of the present disclosure.
- the self-fire extinguishing film 1 is provided on the self-fire extinguishing layer 2, the adhesive layer 5 arranged on one surface side of the self-fire extinguishing layer 2, and the other surface side of the self-fire extinguishing layer 2.
- the arranged flame-resistant layer 6 is provided. The adhesive layer and the flame-resistant layer will be described later.
- the self-fire extinguishing layer 2 contains the heat-meltable binder particles 3 which are particles made of the heat-meltable binder and the fire extinguishing agent particles 4.
- the self-extinguishing film 1 is used, for example, in a mode of covering at least a part of the lithium ion battery element (for example, a mode of wrapping at least a part of the lithium ion battery element).
- the self-fire extinguishing film 1 has a self-fire extinguishing layer 2 containing the heat-meltable binder particles 3 and the fire extinguishing agent particles 4, heat-meltable binding occurs when a predetermined temperature is reached due to abnormal heat generation of the lithium ion battery element.
- the material particles 3 melt and release the fire extinguishing agent particles 4. Therefore, it is possible to suppress the combustion of the lithium ion battery element before the battery exterior is damaged. Since this embodiment is an embodiment in which the heat-meltable binder contained in the self-fire extinguishing layer is the heat-meltable binder particles, the lithium-ion battery element is burned at an early stage for the reason described later. The effect that can be suppressed is more effectively exhibited.
- the self-extinguishing film of the present disclosure includes a self-extinguishing layer.
- the self-extinguishing film of the present disclosure may include only one self-extinguishing layer, or may include two or more layers.
- the self-extinguishing layer contains at least one heat-meltable binder.
- the heat-meltable binder contained in the self-fire extinguishing layer is preferably particles made of the heat-meltable binder (hereinafter, also referred to as heat-meltable binder particles). That is, the self-fire extinguishing layer preferably contains heat-meltable binder particles, which are particles made of the heat-meltable binder.
- the self-fire extinguishing layer contains the heat-meltable binder particles, the effect of suppressing the combustion of the lithium ion battery element at an early stage is more effectively exhibited.
- the reason for this is that when the self-extinguishing layer contains the heat-meltable binder particles, the adhesive area between the adjacent heat-meltable binder particles is small, so that the lithium ion battery elements are adjacent to each other when abnormal heat is generated. It is considered that the adhesion between the matching heat-meltable binder particles is easily broken, which makes it easier for the fire extinguishing agent particles to be released from the self-extinguishing layer.
- the number average particle size of the heat-meltable binder particles is preferably 0.1 ⁇ m to 6.0 ⁇ m.
- the average particle size of the number of heat-meltable binder particles is 0.1 ⁇ m or more, the self-fire extinguishing layer has a collapsible property because there are not too many adhesion points between the heat-meltable binder particles, so that the fire is extinguished. It is easier to release agent particles.
- the number average particle size of the heat-meltable binder particles is more preferably 0.2 ⁇ m or more.
- the heat-meltable binder particles When the number average particle size of the heat-meltable binder particles is 6.0 ⁇ m or less, the heat-meltable binder particles have sufficient adhesion points between the heat-meltable binder particles, whereby the self-fire extinguishing layer is hard to crack and self. There is an advantage that the flexibility of the fire extinguishing layer is further improved. Therefore, for example, it is easier to cover the lithium ion battery element along its shape.
- the number average particle size of the heat-meltable binder particles is more preferably 0.2 ⁇ m to 2.5 ⁇ m, and further preferably 0.2 ⁇ m to 1.0 ⁇ m.
- the reason for this is that when the number average particle size of the heat-meltable binder particles is 2.5 ⁇ m or less, the heat-meltable binder particles move more easily, and therefore the fire is extinguished by the heat-meltable binder particles.
- the heat-meltable binder particles preferably have a half-value width of the maximum peak of the number-based particle size distribution of 0.6 ⁇ m or less.
- Heat-meltable binder Compared to the case where the particle size-based particle size distribution is broad, when the half-value width of the maximum peak of the number-based particle size distribution is 0.6 ⁇ m or less, a large thermo-meltable binder is used. Since small heat-meltable binder particles are suppressed from entering the gaps between the particles, the heat-meltable binder particles are sparsely filled, and the number of adhesion points between the heat-meltable binder particles is reduced. , It is considered that the decrease in the disintegration property of the self-extinguishing layer can be suppressed.
- the heat-meltable binder particles preferably have an average circularity of 0.80 or more, which is obtained by the following formula (1).
- the average circularity is more preferably 0.90 or more.
- Average circularity (perimeter of a circle with the same area as the projected particle area / perimeter of the projected particle image) ... Equation (1)
- the upper limit of the average circularity is not particularly limited and may be 1, but the upper limit is preferably 0.99 from the viewpoint of manufacturing.
- the number of heat-meltable binder particles The average particle size, particle size distribution, and average circularity are determined by observing the fire-extinguishing film with a scanning electron microscope (SEM) and extracting the heat-meltable binder particles by image processing. It can be measured by analyzing individual heat-meltable binder particles.
- SEM scanning electron microscope
- the spherical heat-meltable binder particles can be produced, for example, by the method described in Japanese Patent No. 2851880, and specifically contains a polyolefin having a carboxy group introduced therein and a basic substance such as potassium hydroxide. It can be produced by putting an aqueous dispersion in a pressure-resistant container, heating it to melt the polyolefin, and stirring it at high speed.
- the basic substance surrounds the polyolefin particles into which the carboxy group has been introduced, and the association between the polyolefin particles is prevented, so that spherical heat-meltable binder particles can be obtained.
- the heat-meltable binder particles from which the carboxy group on the surface has been removed by washing with warm water it is preferable to use the heat-meltable binder particles from which the carboxy group on the surface has been removed by washing with warm water.
- the pH of the aqueous dispersion of heat-meltable binder particles is 8.0 to 11. It is preferably 0.0.
- the pH of the aqueous dispersion of the heat-meltable binder particles is within the above range, the influence on the battery reaction can be further reduced.
- the heat-meltable binder is preferably a resin.
- the resin constituting the heat-meltable binder conforms to JIS K7210-1995 and has a melt flow rate (hereinafter, also referred to as “MFR”) of 20 g / 10 measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N. It is preferably from 1 minute to 55 g / 10 minutes.
- MFR melt flow rate
- the MFR of the resin constituting the heat-meltable binder means a value measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K7210-1995. More specifically, the MFR is subjected to the conditions of a temperature of 190 ° C. and a load of 21.18 N by using a fixed die (inner diameter 2.095 mm, length 8 mm) by the A method (mass measurement method) in JIS K7210-1995. To measure.
- the melting point of the resin constituting the heat-meltable binder is preferably 100 ° C. to 140 ° C., more preferably 110 ° C. to 140 ° C.
- the fire extinguishing agent particles are more likely to be released from the self-extinguishing layer, and as a result, the combustion of the lithium ion battery element can be suppressed at an early stage. Is played more effectively.
- the heat-meltable binder preferably contains at least one type of polyolefin.
- the polyolefin include polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, propylene / 1-hexene copolymer and the like.
- the polyolefin preferably has a carboxy group (eg, maleic acid structure) at the end.
- the content of the heat-meltable binder in the self-fire extinguishing layer depends on the type of fire extinguishing agent particles and the like, but is preferably 10% by mass to 50% by mass, preferably 20% by mass, based on the total amount of the self-fire extinguishing layer. More preferably, it is about 40% by mass.
- the self-extinguishing layer contains at least one kind of extinguishing agent particles.
- the average particle size of the number of fire extinguishing agent particles depends on the particle size of the heat-meltable binder particles, but is preferably 0.1 ⁇ m to 5.0 ⁇ m, and more preferably 0.2 ⁇ m to 2.5 ⁇ m. preferable.
- the number average particle size of the fire extinguishing agent particles is 0.8 to 4 times the number average particle size of the heat-meltable binder particles, coarsening due to aggregation of the fire extinguishing agent particles is suppressed. Since the fire extinguishing agent particles are uniformly dispersed among the heat-meltable binder particles and easily pass through the gaps between the heat-meltable binder particles whose adhesion has been released, the fire extinguishing action tends to be exhibited at an early stage.
- fire extinguishing agent particles those in which the fire extinguishing agent itself is in the form of particles or particles containing the fire extinguishing agent can be used.
- a fire extinguisher for example Guanidine phosphate, Melamine polyphosphate, Phosphoric trichloride, reaction products with 4,4'-isopropylidenediphenol and phenol, Phosphate ester Organophosphorus compounds, Phosphoric trichloride, polymer with 1,3-benzenediol, phenyl ester, Antimony trioxide, Ethylene bispentabromobenzene, 2,3-Dibromopropyl ether, Triallyl isocyanate 6 bromide, Bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] sulfone, Ethylene bispentabromobenzene / antimony trioxide, Potassium perfluorobutane sulf
- the fire extinguishing agent particles are preferably dispersed in the self-extinguishing layer.
- the fire extinguishing agent particles are more easily released from the self-extinguishing layer, and as a result, the effect of suppressing the combustion of the lithium ion battery element at an early stage is more effectively exhibited.
- the fact that the fire extinguishing agent particles are dispersed in the self-extinguishing layer means that the aggregation of the fire extinguishing agent particles in the self-extinguishing layer is suppressed.
- the number of agglomerates of fire extinguishing agent particles having a diameter of 0.5 mm or more is 10 in terms of the number per square region having a side of 10 cm.
- An embodiment in which the number of particles is less than or equal to (more preferably 1 or less, still more preferably 0) can be mentioned.
- the fire extinguishing agent particles are easily dispersed in the self-extinguishing layer (that is, the aggregation of the fire extinguishing agent particles is further suppressed. ), As a result, the fire extinguishing agent particles are more easily released from the self-extinguishing layer, and the above effect is more effectively exhibited.
- the content of the heat-meltable binder in the self-fire extinguishing layer depends on the type of fire extinguishing agent particles and the like, but is preferably 20% by mass to 70% by mass, preferably 30% by mass, based on the total amount of the self-fire extinguishing layer. It is more preferably to 60% by mass, and even more preferably 40% by mass to 50% by mass.
- the self-extinguishing film of the present disclosure preferably further includes at least one pressure-sensitive adhesive layer. This makes it easier to fix the self-extinguishing film and the lithium-ion battery element, and as a result, the misalignment and winding of the lithium-ion battery element are more effectively suppressed.
- the self-extinguishing film 1 shown in FIG. 1 includes an adhesive layer 5 on one surface side of the self-extinguishing layer 2.
- the pressure-sensitive adhesive layer 5 is adhered to the periphery of the lithium-ion battery element 50 shown in FIG. 2, and at least a part of the lithium-ion battery element 50 is directly coated with the self-extinguishing film 1 to form a lithium-ion battery.
- the element 50 is firmly fixed, and the prevention of misalignment and unwinding of the lithium ion battery element 50 is more effectively realized.
- the adhesive layer 5 may be formed on the entire surface of the self-fire extinguishing layer 2, but is provided on a part of the self-fire extinguishing layer 2 such as a polka dot pattern (dot shape), a striped pattern (striped shape), and a checkered pattern (that is,). It is more preferable to provide it so that the non-forming portion is present.) By forming the non-coated portion of the adhesive material, the fire extinguishing agent particles tend to easily move to the lithium ion battery element through the non-formed portion.
- the adhesive material it is preferable to use a material that does not swell or dissolve in a non-aqueous electrolyte solution, and for example, a non-silicone adhesive such as a urethane adhesive, an imide adhesive, an epoxy adhesive, or an acrylic adhesive. Can be mentioned.
- a non-silicone adhesive such as a urethane adhesive, an imide adhesive, an epoxy adhesive, or an acrylic adhesive.
- the self-extinguishing film of the present disclosure preferably further includes at least one flame-resistant layer from the viewpoint of further suppressing the spread of fire of the lithium ion battery.
- the self-extinguishing film 1 shown in FIG. 1 is provided with a flame-resistant layer 6 on a surface opposite to the surface side provided with the adhesive layer.
- a flame-resistant layer 6 By having the flame resistant layer 6, even if the lithium ion battery element ignites, it is possible to more effectively suppress the spread of fire to the outside of the self-extinguishing film.
- the resin constituting the flame-resistant layer examples include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamide-imide (PAI), and polytetrafluoroethylene (PTFE). These resins constituting the flame-resistant layer may form a film having a function as the flame-resistant layer. These resins constituting the flame resistant layer may contain fire extinguishing agent particles. Further, the flame resistant layer may be formed by using a film into which a PP (polypropylene) flame retardant (halogen type, phosphoric acid type) is introduced.
- PP polypropylene flame retardant
- a preferred embodiment of the self-extinguishing film of the present disclosure is an embodiment in which an adhesive layer is provided on one side of the self-extinguishing layer and a flame-resistant layer is provided on the other side.
- An example of the method for producing a self-extinguishing film for a lithium ion battery of the present disclosure is A step of preparing an aqueous dispersion A containing a heat-meltable binder and fire extinguishing agent particles, and The process of applying the aqueous dispersion A on the substrate to form a coating film, The process of heating and drying the coating film at a temperature below the melting point of the heat-meltable binder, and including.
- an aqueous dispersion A containing a heat-meltable binder and fire extinguishing agent particles is applied onto a base material and dried by heating to form a self-extinguishing layer.
- a self-extinguishing film having a base material and a self-extinguishing layer provided on the base material is produced. Further, in the above example, when the self-extinguishing layer is peeled off from the base material, a self-extinguishing film composed of only the self-extinguishing layer (self-supporting film) can be produced.
- the base material and the self-fire extinguishing layer are bonded to each other with an adhesive or the like, and the base material and the self-fire extinguishing layer provided on the base material are formed.
- a self-extinguishing film of the aspect provided may be produced.
- the base material examples include metals, the above-mentioned flame-resistant layer (for example, polyphenylene sulfide (PPS) film), and the like.
- PPS polyphenylene sulfide
- the coating film is heat-dried at a temperature lower than the melting point of the heat-meltable binder.
- the shape of the heat-meltable binder for example, heat-meltable binder
- the coating film is heated above the melting point (mp) of the heat-meltable binder. It is easy to maintain the shape of the material particles). Therefore, a self-extinguishing layer having excellent release property of fire extinguishing agent particles can be formed.
- the lower limit of the heat-drying temperature is not particularly limited, but from the viewpoint of the strength of the self-extinguishing layer formed (that is, crack suppression), the lower limit of the heat-drying temperature is preferably set. It is "mp-50" (° C.) to "mp-30" (° C.).
- the step of preparing the aqueous dispersion liquid A is a step of preparing the aqueous dispersion liquid A (hereinafter, also referred to as “self-fire extinguishing layer coating liquid”) containing the heat-meltable binder and the fire extinguishing agent particles.
- the step of preparing the aqueous dispersion A is An aqueous dispersion of particles made of a heat-meltable binder (that is, heat-meltable binder particles), Water dispersion of fire extinguishing agent particles and It is preferable to include a step of mixing. Thereby, the dispersibility of the fire extinguishing agent particles can be further improved.
- the aqueous dispersion A may contain an adhesive material such as carboxymethyl cellulose (CMC) and an adhesive aid such as styrene butadiene rubber (SBR), if necessary.
- an adhesive material such as carboxymethyl cellulose (CMC) and an adhesive aid such as styrene butadiene rubber (SBR), if necessary.
- SBR styrene butadiene rubber
- the pH of the aqueous dispersion of the heat-meltable binder particles is preferably 8.0 to 11.0.
- the amount of carboxy groups on the surface of the heat-meltable binder particles is reduced, the influence of the self-extinguishing film on the lithium ion battery element can be further reduced.
- the production method according to an example may include other steps other than the above-mentioned steps.
- Examples of other steps include the above-mentioned step of forming the pressure-sensitive adhesive layer.
- the lithium ion battery of the present disclosure is A lithium ion battery element including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode.
- the lithium ion battery of the present disclosure includes the self-extinguishing film of the present disclosure, the same effect as the effect of the self-extinguishing film of the present disclosure described above (that is, the effect of suppressing the combustion of the lithium ion battery element at an early stage). Is played.
- the lithium ion battery of the present disclosure from the viewpoint that the above effects are more effectively exhibited, it is preferable that at least a part of the lithium ion battery element is wrapped with a self-extinguishing film.
- FIG. 2 is a partially cutaway perspective view showing an embodiment of the lithium ion battery of the present disclosure.
- the lithium ion battery 100 is formed by accommodating a lithium ion battery element 50 whose circumference is surrounded by a self-extinguishing film 1 in a battery outer body 10.
- the lithium ion battery element 50 is formed by laminating or winding a positive electrode 20, a negative electrode 30, and a separator 40, and is sealed with the positive electrode terminal 21 and the negative electrode terminal 31 pulled out from the edge of the battery exterior 10. By being accommodated, it is accommodated in the accommodating portion 10a.
- the lithium ion battery of the present disclosure from the viewpoint of further suppressing the misalignment of the lithium ion battery element, it is preferable that at least a part of the lithium ion battery element and at least a part of the self-extinguishing film are adhered to each other. ..
- FIG. 3 is a cross-sectional view taken along the line II-II of the lithium ion battery shown in FIG. As shown in FIG. 3, in this embodiment, since the self-extinguishing film 1 surrounding the lithium ion battery element 50 is adhered to the lithium ion battery element 50, the position of the lithium ion battery element 50 is prevented from being displaced.
- the lithium ion battery element 50 surrounded by the self-extinguishing film 1 is arranged in the accommodating portion 10a of the battery exterior body 10, and the accommodating portion 10a is filled with the electrolytic solution 60 to form a battery.
- the edge portion of the exterior body 10 is heat-sealed to form a sealing portion 10b, which is sealed and housed in the battery exterior body 10.
- the positive electrode is usually composed of a positive electrode active material and a positive electrode current collector, and may contain a conductive auxiliary agent, a binder, a solid electrolyte, and the like, if necessary.
- the positive electrode active material is not particularly limited, and generally known ones can be used. Examples of the positive electrode active material include lithium-containing composite oxides such as lithium cobalt oxide, lithium nickel oxide, lithium manganate, spinel-type lithium composite oxide, and lithium titanate.
- the negative electrode is usually composed of a negative electrode active material and a negative electrode current collector, and may contain a conductive auxiliary agent, a binder, a solid electrolyte, and the like, if necessary.
- the negative electrode active material is not particularly limited, and generally known materials can be used. For example, carbon materials such as graphite and hard carbon, Si and Si alloys and the like can be mentioned.
- the electrolyte is not particularly limited as long as it has lithium ion conductivity, and generally known electrolytes can be used, and non-aqueous electrolytes and inorganic solid electrolytes can be used.
- non-aqueous electrolyte solution examples include LiPF 6 , LiBF 4 , LiN (SO 2 CF 3 ) 2 , and LiN (SO 2 CF) in a mixed solvent of carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. 2 CF 3 )
- a non-aqueous electrolyte solution in which a Li electrolyte such as 2 or the like is dissolved can be mentioned.
- the inorganic solid electrolyte examples include a perovskite-type oxide solid electrolyte such as (Li, La) TiO 3 and an oxide such as a pearcon-type oxide solid electrolyte such as Li (Al, Ti) (PO 4 ) 3.
- Solid electrolytes, Li 2 SP 2 S 5 , Li 2 S-SiS 2 , LiI-Li 2 S-SiS 2 , LiI-Si 2 SP 2 S 5 , LiI-Li 2 SP 2 O 5 , LiI-Li 3 PO 4- P 2 S 5 and the like sulfide solid electrolytes can be mentioned.
- the separator is provided so as to be interposed between the positive electrode and the negative electrode, and insulates the positive electrode and the negative electrode.
- a material that is stable against a non-aqueous electrolytic solution and has excellent liquid retention properties For example, a polyolefin porous film containing polyethylene, polypropylene and the like; polyolefin fibers (polyethylene fiber, polypropylene fiber). Etc.), non-woven fabrics containing glass fibers, cellulose fibers, polypropylene fibers, etc .; and the like can be used.
- Example 1 ⁇ Making a self-extinguishing film> Fire extinguishing agent particles (Phosphoric trichloride, polymer with 1,3-benzenediol, phenyl ester, number average particles) in an aqueous solution containing 1% by mass to 5% by mass of carboxymethyl cellulose so that the content in the self-fire extinguishing layer becomes 15% by mass. A diameter of 0.8 ⁇ m) was added so that the content in the self-extinguishing layer was 45% by mass, and the mixture was uniformly dispersed using a planetary mixer.
- Phosphoric trichloride polymer with 1,3-benzenediol, phenyl ester, number average particles
- a fire extinguishing agent particle aqueous dispersion was prepared.
- the aqueous dispersion of the heat-meltable binder particles 1 (number average particle size: 1.0 ⁇ m, average circularity: 0.91, pH: 9, melting point 110 ° C., MFR : 25 g / 10 min; Mitsui Kagaku Co., Ltd .: Chemipal W401) is added so that the content of the heat-meltable binder particles 1 in the self-extinguishing layer is 30% by mass and uniformly dispersed to apply the self-fire extinguishing layer.
- a liquid (corresponding to the above-mentioned aqueous dispersion A) was prepared.
- the self-fire extinguishing layer coating liquid was applied onto a polyphenylene sulfide (PPS) film as a flame-resistant layer and dried by heating at 120 ° C. to form a self-fire extinguishing layer having a thickness of 50 ⁇ m.
- PPS polyphenylene sulfide
- a methyl methacrylate-based adhesive was applied in a dot shape on the self-extinguishing layer to form an adhesive layer to obtain a self-extinguishing film.
- SBR styrene butadiene rubber
- CMC carboxymethyl cellulose
- a positive electrode slurry was prepared. Next, using an aluminum foil (porous foil) having a thickness of 15 ⁇ m as the positive electrode current collector, the positive electrode slurry is coated on the positive electrode current collector so that the mass of the activated carbon after drying is 4 mg / cm 2, and dried. To prepare a positive electrode.
- the positive electrode and the negative electrode prepared as described above are punched out to form a rectangle having a size of 60 mm ⁇ 40 mm, and the slurry coating film in the region of 20 mm ⁇ 40 mm on one end side of the long side is peeled off, leaving the slurry coating film of 40 mm ⁇ 40 mm. I dropped it and attached the electrode terminal.
- a lithium ion battery element was manufactured by facing the coating film portions of the positive electrode and the negative electrode with a cellulose separator having a thickness of 20 ⁇ m interposed between the positive electrode and the negative electrode.
- the entire lithium-ion battery element except for one end to which the electrode terminal of the lithium-ion battery element was attached and the other end facing the one end was wrapped with a self-extinguishing film, and the positive electrode, the separator, and the negative electrode were fixed.
- a mixed solvent of 35% by volume of ethylene carbonate (EC), 35% by volume of dimethyl carbonate (DMC) and 30% by volume of ethylmethyl carbonate (EMC) was used, and 1 mol / L of LiPF 6 was added to the mixed solvent to make it non-aqueous.
- An electrolytic solution was prepared.
- Both sides of an aluminum foil having a thickness of 40 ⁇ m are subjected to chemical conversion treatment, and a stretched nylon film having a thickness of 25 ⁇ m is bonded to one of the chemical conversion treated surfaces by a dry laminating method using a two-component curable polyurethane adhesive.
- a polypropylene film (molecular weight: 5 million) having a thickness of 50 ⁇ m was further bonded onto the nylon film in the same manner to obtain a film for the battery exterior.
- a lithium ion battery element wrapped in a self-extinguishing film and a metallic lithium foil for lithium predoping are housed in a battery exterior body in which three sides of the battery exterior body film are heat-welded, and the non-aqueous electrolyte solution is applied. After injection, the opening of the battery exterior was heat-bonded and sealed at 150 ° C. to prepare a lithium-ion battery.
- Example 1 A lithium ion battery was produced in the same manner as in Example 1 except that the lithium ion battery element was not wrapped with a self-extinguishing film.
- the dispersibility of the extinguishing agent particles in the self-extinguishing layer was confirmed as follows.
- the self-extinguishing film was observed in a plan view, and the number of agglomerates of fire extinguishing agent particles having a diameter of 0.5 mm or more was confirmed.
- the number of self-extinguishing films was calculated by converting them into the number of self-extinguishing films per 10 cm square area.
- the dispersibility of the fire extinguishing agent particles in the self-extinguishing layer was evaluated according to the following evaluation criteria. The results are shown in the "Fire extinguishing agent dispersibility" column of Table 1. In the following evaluation criteria, the rank with the best dispersibility of the fire extinguishing agent particles in the self-extinguishing layer is A.
- A The number of agglomerates of fire extinguishing agent particles having a diameter of 0.5 mm or more was 0 when converted to the number per square region having a side of 10 cm.
- B The number of agglomerates of fire extinguishing agent particles having a diameter of 0.5 mm or more was 1 to 10 when converted into the number of agglomerates per square region having a side of 10 cm.
- C The number of agglomerates of fire extinguishing agent particles having a diameter of 0.5 mm or more was more than 10 when converted into the number of agglomerates per square region having a side of 10 cm.
- the lithium-ion battery of Example 1 in which the lithium-ion battery element is wrapped with a self-extinguishing film has a more suppressed temperature rise inside the lithium-ion battery than the lithium-ion battery of Comparative Example 1. It was confirmed that ignition could be prevented.
- a lithium ion battery was produced in the same manner as in Example 1 except that the heat-meltable binder particles 1 were changed to the heat-meltable binder particles shown in Table 1 below, and a forced internal short-circuit test was performed.
- Table 1 shows the dispersibility of the fire extinguishing agent particles in the self-extinguishing layer and the maximum temperature reached inside the lithium ion battery by the forced internal short circuit test.
- the average number particle size of the heat-meltable binder particles is 1.0 ⁇ m or less, and the average number particle size of the fire extinguishing agent particles and the heat-meltable binder particles is about the same (0.8 to 4 times). ), Since the difference between the temperature in the cell and the melting point is small, it was confirmed that the fire extinguishing agent particles were released at an early stage to exhibit the fire extinguishing action.
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Abstract
Description
近年、リチウムイオン電池に代表される電池の安全性、即ち、上記電池の発火抑制及び消火に関して、種々の検討がなされている。
例えば、特許文献1には、電池の非正常的な作動状態によって電池の内部が高温になっても、電池の発火を防止するか、または発火時において消火が行われるようにする、安全性が向上した二次電池用パウチとして、正極、負極及び正極と負極との間に介されたセパレータを含む電極組立体を含み、上記電極組立体が内部パウチに収納され、電極リードが内部パウチから引き出されており、上記内部パウチが外部パウチに収納され、電極リードが外部パウチから引き出されており、上記内部パウチと外部パウチとの間の空間に、***材が含まれている、パウチ型二次電池が開示されている。
また、特許文献2には、蓄電装置全体の小型化及び軽量化を確保しながら、リチウムの発火による火災を初期消火で抑制することができる電気化学デバイスとして、負極、セパレータ及び正極を積層してなる電極積層体と、所定温度に達すると燃焼してエアロゾルを発生させる消火薬剤と、リチウムイオン含有電解質及び有機溶媒を含む電解液であって、上記電極積層体及び上記消火薬剤を浸漬する電解液と、上記電極積層体、上記消火薬剤及び上記電解液を収納する外装体と、を含む電気化学デバイスが開示されている。
特許文献2:特許第6431147号公報
本開示の課題は、リチウムイオン電池素子の燃焼を早期に抑制できるリチウムイオン電池用自己消火性フィルム及びその製造方法、並びに、上記リチウムイオン電池用自己消火性フィルムを備えるリチウムイオン電池を提供することである。
<1> 熱溶融性結着材と消火剤粒子とを含有する自己消火層を備える、リチウムイオン電池用自己消火性フィルム。
<2> 前記自己消火層が、前記熱溶融性結着材からなる粒子である熱溶融性結着材粒子を含有する、<1>に記載のリチウムイオン電池用自己消火性フィルム。
<3> 前記熱溶融性結着材粒子の個数平均粒径が、0.1μm~6.0μmである、<2>に記載のリチウムイオン電池用自己消火性フィルム。
<4> 前記熱溶融性結着材粒子の個数平均粒径が、0.2μm~2.5μmである、<2>又は<3>に記載のリチウムイオン電池用自己消火性フィルム。
<5> 前記熱溶融性結着材粒子は、下記式(1)で求められる平均円形度が0.80以上である、<2>~<4>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
平均円形度=(粒子投影面積と同じ面積の円の周囲長/粒子投影像の周囲長) … 式(1)
<6> 前記熱溶融性結着材が樹脂であり、
前記樹脂は、JIS K7210-1995に準拠し、温度190℃、荷重21.18Nの条件で測定されたメルトフローレートが20g/10分~55g/10分である、
<1>~<5>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
<7> 前記熱溶融性結着材が、ポリオレフィンを含有する、<1>~<6>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
<8> 前記消火剤粒子の個数平均粒径が、0.1μm~5.0μmである、<1>~<7>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
<9> 更に、粘着材層を備える、<1>~<8>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
<10> 更に、
前記自己消火層の一方の面側に配置された粘着材層と、
前記自己消火層の他方の面側に配置された耐燃性層と、
を備える、
<1>~<8>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
<11> 平面視した場合に、前記消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数が、一辺10cmの正方形領域あたりの個数に換算して10個以下である、<1>~<10>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルム。
前記熱溶融性結着材と前記消火剤粒子とを含有する水性分散液Aを準備する工程と、
基材上に前記水性分散液Aを塗布して塗膜を形成する工程と、
前記塗膜を前記熱溶融性結着材の融点未満の温度で加熱乾燥する工程と、
を含むリチウムイオン電池用自己消火性フィルムの製造方法。
<13> 前記水性分散液Aを準備する工程が、前記熱溶融性結着材からなる粒子である熱溶融性結着材粒子の水分散液と、前記消火剤粒子の水分散液と、を混合する工程を含み、
前記熱溶融性結着材粒子の水分散液のpHが、8.0~11.0である、
<12>に記載のリチウムイオン電池用自己消火性フィルムの製造方法。
<14> 正極と、負極と、前記正極及び前記負極の間に介在するセパレータと、
を含むリチウムイオン電池素子と、
<1>~<11>のいずれか1つに記載のリチウムイオン電池用自己消火性フィルムと、
を備えるリチウムイオン電池。
<15> 前記リチウムイオン電池素子の少なくとも一部分と、
前記リチウムイオン電池用自己消火性フィルムの少なくとも一部分と、
が接着されている、<14>に記載のリチウムイオン電池。
本開示において、組成物中の各成分の量は、組成物中に各成分に該当する物質が複数存在する場合は、特に断らない限り、組成物中に存在する当該複数の物質の合計量を意味する。
本開示のリチウムイオン電池用自己消火性フィルム(以下、「自己消火性フィルム」ともいう。)は、熱溶融性結着材と消火剤粒子とを含有する自己消火層を備える。
本開示の自己消火性フィルムは、リチウムイオン電池素子とともに用いられる。この際、リチウムイオン電池素子に異常発熱が生じた際に、リチウムイオン電池素子の燃焼を早期に抑制できる。
リチウムイオン電池の燃焼を未然に防止できること、及び、
リチウムイオン電池素子の燃焼が実際に生じた場合であっても早期に消火できること
の両方が包含される。
図1に示されるように、自己消火性フィルム1は、自己消火層2と、自己消火層2の一方の面側に配置された粘着材層5と、自己消火層2の他方の面側に配置された耐燃性層6と、を備える。粘着材層及び耐燃性層については後述する。
自己消火性フィルム1は、例えば、リチウムイオン電池素子の少なくとも一部を被覆する態様(例えば、リチウムイオン電池素子の少なくとも一部を包む態様)で用いられる。
従って、電池外装体の破損前にリチウムイオン電池素子の燃焼を抑制することできる。
この実施形態は、自己消火層に含有される熱溶融性結着材が、熱溶融性結着材粒子である態様の実施形態であるため、後述する理由により、リチウムイオン電池素子の燃焼を早期に抑制できる効果がより効果的に発揮される。
本開示の自己消火性フィルムは、自己消火層を備える。
本開示の自己消火性フィルムは、自己消火層を1層のみ備えてもよいし、2層以上備えてもよい。
自己消火層は、熱溶融性結着材を少なくとも1種含有する。
自己消火層が熱溶融性結着材粒子を含有する場合には、リチウムイオン電池素子の燃焼を早期に抑制できる効果がより効果的に奏される。
この理由は、自己消火層が熱溶融性結着材粒子を含有する場合には、隣り合う熱溶融性結着材粒子同士の接着面積が小さいことにより、リチウムイオン電池素子の異常発熱時、隣り合う熱溶融性結着材粒子同士の接着が解けやすく、これにより、自己消火層から消火剤粒子がより放出されやすいためと考えられる。
熱溶融性結着材粒子の個数平均粒径が0.1μm以上である場合には、熱溶融性結着材粒子同士の接着点が多過ぎずに自己消火層が崩壊性を有するため、消火剤粒子をより放出し易い。熱溶融性結着材粒子の個数平均粒径は、より好ましくは0.2μm以上である。
熱溶融性結着材粒子の個数平均粒径が6.0μm以下である場合には、充分な熱溶融性結着材粒子同士の接着点を有し、これにより自己消火層が割れにくく、自己消火層の可撓性がより向上するという利点がある。このため、例えば、リチウムイオン電池素子をその形状に沿ってより被覆しやすい。
熱溶融性結着材粒子の個数平均粒径が0.2μm~2.5μmである場合には、リチウムイオン電池素子の燃焼を早期に抑制できる効果がより効果的に奏される。
この理由は、熱溶融性結着材粒子の個数平均粒径が2.5μm以下である場合には、熱溶融性結着材粒子がより移動しやすいため、熱溶融性結着材粒子によって消火剤粒子の放出が妨げられる現象が抑制され、消火剤粒子がより放出され易いためと考えられる。
かかる効果は、後述する消火剤粒子の分散性(凝集抑制性)を確認することによっても確認できる。
熱溶融性結着材粒子の個数基準の粒度分布がブロードである場合に比べ、個数基準の粒度分布の最大ピークの半値幅が、0.6μm以下である場合は、大きな熱溶融性結着材粒子同士の間隙に小さな熱溶融性結着材粒子が入り込むことが抑制されるため、熱溶融性結着材粒子が疎に充填され、熱溶融性結着材粒子同士の接着点が少なくなって、自己消火層の崩壊性の低下を抑えることができる、と考えられる。
平均円形度=(粒子投影面積と同じ面積の円の周囲長/粒子投影像の周囲長) … 式(1)
かかる観点から、自己消火層を形成するための原料として、熱溶融性結着材粒子の水分散液を用いる場合、熱溶融性結着材粒子の水分散液のpHは、8.0~11.0であることが好ましい。
熱溶融性結着材粒子の水分散液のpHが上記範囲内であることで、電池反応へ影響をより軽減できる。
熱溶融性結着材を構成する樹脂は、JIS K7210-1995に準拠し、温度190℃、荷重21.18Nの条件で測定されたメルトフローレート(以下、「MFR」ともいう)が20g/10分~55g/10分であることが好ましい。
熱溶融性結着材を構成する樹脂のMFRが20g/10分以上である場合には、溶融した熱溶融性結着材の流動性により優れるので、異常発熱により自己消火層の崩壊がより促進され、自己消火層から消火剤粒子がより放出されやすくなり、その結果、リチウムイオン電池素子の燃焼を早期に抑制できる効果がより効果的に奏される。
MFRは、より具体的には、JIS K7210-1995におけるA法(質量測定法)により、固定式ダイ(内径2.095mm、長さ8mm)を用い、温度190℃、荷重21.18Nの条件にて測定する。
熱溶融性結着材を構成する樹脂の融点が上記範囲である場合には、自己消火層から消火剤粒子がより放出されやすくなり、その結果、リチウムイオン電池素子の燃焼を早期に抑制できる効果がより効果的に奏される。
ポリオレフィンとしては、例えば、ポリエチレン、ポリプロピレン、エチレン/プロピレン共重合体、エチレン/1-ブテン共重合体、プロピレン/1-ヘキセン共重合体などが挙げられる。
ポリオレフィンは、末端にカルボキシ基(例えばマレイン酸構造)を有することが好ましい。
自己消火層は、消火剤粒子を少なくとも1種含有する。
消火剤粒子の個数平均粒径は、熱溶融性結着材粒子の粒径にもよるが、0.1μm~5.0μmであることが好ましく、0.2μm~2.5μmであることがより好ましい。
消火剤としては、例えば、
リン酸グアニジン、
ポリリン酸メラミン、
Phosphoric trichloride,reaction products with 4,4’-isopropylidenediphenol and phenol、
リン酸エステル有機リン酸化合物、
Phosphoric trichloride,polymer with 1,3-benzenediol,phenyl ester、
三酸化アンチモン、
エチレンビスペンタブロモベンゼン、
2,3-ジブロモプロピルエーテル、
トリアリルイソシアネート6臭化物、
ビス[3,5‐ジブロモ-4-(2,3-ジブロモプロポキシ)フェニル]スルホン、
エチレンビスペンタブロモベンゼン/三酸化アンチモン、
パーフロロブタンスルホン酸カリウム塩類、
炭化ケイ素、
球状アルミナ、
特殊炭素繊維、
ホウ酸化チタン、
等を挙げることができる。
ここで、消火剤粒子が自己消火層中に分散されているとは、自己消火層中における消火剤粒子の凝集が抑制されていることを意味する。
好ましい態様として自己消火性フィルムを平面視した場合に、消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数が、一辺10cmの正方形領域あたりの個数に換算して10個以下(より好ましくは1個以下、更に好ましくは0個)である態様が挙げられる。
本開示の自己消火性フィルムは、更に、粘着材層を少なくとも1層備えることが好ましい。
これにより、自己消火性フィルムとリチウムイオン電池素子とを固定しやすくなり、その結果、リチウムイオン電池素子の位置ずれや巻きずれがより効果的に抑制される。
この一例では、粘着材層5を、図2に示すリチウムイオン電池素子50の周囲に接着させ、リチウムイオン電池素子50の少なくとも一部を自己消火性フィルム1で直接被覆することで、リチウムイオン電池素子50がしっかりと固定され、リチウムイオン電池素子50の位置ずれや巻きずれの防止がより効果的に実現される。
粘着材の非塗布部を形成することで、消火剤粒子が非形成部を通ってリチウムイオン電池素子に移動し易くなる傾向がある。
本開示の自己消火性フィルムは、リチウムイオン電池の延焼をより抑制する観点から、更に、耐燃性層を少なくとも1層備えることが好ましい。
耐燃性層6を有することで、リチウムイオン電池素子が発火しても自己消火性フィルム外への延焼をより効果的に抑制することができる。
耐燃性層を構成するこれらの樹脂は、耐燃性層としての機能をもつフィルムを形成してもよい。耐燃性層を構成するこれらの樹脂は、消火剤粒子を含んでいてもよい。また、耐燃性層は、PP(ポリプロピレン)難燃剤(ハロゲン系,リン酸系)を導入したフィルムを用いて形成されていてもよい。
自己消火層の一方の面側に粘着材層を備え、他方の面側に耐燃性層を備えることによって、リチウムイオン電池がしっかり固定され、リチウムイオン電池素子の位置ずれや巻きずれを防止するとともに、リチウムイオン電池の延焼の抑制が、より効果的に実現されるためである。
本開示のリチウムイオン電池用自己消火性フィルムの製造方法の一例は、
熱溶融性結着材と消火剤粒子とを含有する水性分散液Aを準備する工程と、
基材上に水性分散液Aを塗布して塗膜を形成する工程と、
塗膜を熱溶融性結着材の融点未満の温度で加熱乾燥する工程と、
を含む。
上記一例に係る製法では、基材と、基材上に設けられた自己消火層と、を備える態様の自己消火性フィルムが製造される。
また、上記一例において、基材から自己消火層を剥離した場合には、自己消火層(自立膜)のみからなる自己消火性フィルムを製造することもできる。
また、上記一例において、基材から自己消火層を剥離した後、基材と自己消火層とを接着剤等で貼り合わせて、基材と、基材上に設けられた自己消火層と、を備える態様の自己消火性フィルムを製造してもよい。
これにより、塗膜を熱溶融性結着材の融点(mp)以上で加熱した場合に比べて、形成された自己消火層において、熱溶融性結着材の形状(例えば、熱溶融性結着材粒子の形状)を維持しやすい。このため、消火剤粒子の放出性に優れた自己消火層を形成できる。
水性分散液Aを準備する工程は、熱溶融性結着材と消火剤粒子とを含有する水性分散液A(以下、「自己消火層塗工液」ともいう)を準備する工程である。
水性分散液Aを準備する工程は、
熱溶融性結着材からなる粒子(即ち、熱溶融性結着材粒子)の水分散液と、
消火剤粒子の水分散液と、
を混合する工程を含むことが好ましい。
これにより、消火剤粒子の分散性をより向上させることができる。
この場合には、熱溶融性結着材粒子の表面のカルボキシ基の量が低減されるので、リチウムイオン電池素子に対する自己消火性フィルムの影響をより軽減できる。
その他の工程としては、前述した粘着材層を形成する工程等が挙げられる。
本開示のリチウムイオン電池は、
正極と、負極と、正極及び負極の間に介在するセパレータと、を含むリチウムイオン電池素子と、
前述した本開示の自己消火性フィルムと、
を備える。
図2に示すように、リチウムイオン電池100は、自己消火性フィルム1で周囲を包まれたリチウムイオン電池素子50を電池外装体10に収容して形成されている。リチウムイオン電池素子50は、正極20と負極30とセパレータ40を積層又は巻回させて形成されており、電池外装体10の縁部から正極端子21と負極端子31が引き出された状態で封止されることにより、収容部10aに収容されている。
図3に示すように、この一実施形態では、リチウムイオン電池素子50に、その周囲を包む自己消火性フィルム1が接着されているため、リチウムイオン電池素子50の位置ずれが防止される。
正極活物質としては、例えば、コバルト酸リチウム、ニッケル酸リチウム、マンガン酸リチウム、スピネル型リチウム複合酸化物、チタン酸リチウム等のリチウム含有複合酸化物を挙げることができる。
例えば、グラファイト、ハードカーボン等の炭素材料、Si及びSi合金等を挙げることができる。
上記セパレータとしては、非水電解液に対して安定であり、保液性に優れた材料を用いることが好ましく、例えば、ポリエチレン、ポリプロピレン等を含むポリオレフィン多孔質膜;ポリオレフィン繊維(ポリエチレン繊維、ポリプロピレン繊維等)、ガラス繊維、セルロース繊維、ポリイミド繊維等を含む不織布;などを用いることができる。
<自己消火性フィルムの作製>
自己消火層中の含有率が15質量%になるようにカルボキシメチルセルロースを1質量%~5質量%含む水溶液に、消火剤粒子(Phosphoric trichloride,polymer with 1,3-benzenediol,phenyl ester、個数平均粒径0.8μm)を自己消火層中の含有率が45質量%になるように加え、プラネタリーミキサーを用いて均一に分散させ、スチレンブタジエンゴム(個数平均粒径:1.2μm、日本ゼオン社製:2001)を自己消火層中の含有率が10質量%になるように加えて消火剤粒子水分散液を作製した。
作製された消火剤粒子水分散液に、熱溶融性結着材粒子1の水分散液(個数平均粒径:1.0μm、平均円形度:0.91、pH:9、融点110℃、MFR:25g/10min;三井化学社製:ケミパールW401)を自己消火層中の熱溶融性結着材粒子1の含有率が30質量%になるように加えて均一分散させて、自己消火層塗工液(前述した水性分散液Aに対応)を作製した。
負極活物質としてのグラファイト95質量部、バインダーとしてのスチレンブタジエンゴム(SBR)1質量部、増粘材としてのカルボキシメチルセルロース(CMC)1質量部、溶媒としての水100質量部を混合し、負極用スラリーを調製した。
次に、負極集電体として厚み10μmの銅箔(多孔箔)を用い、乾燥後のグラファイトの質量が4mg/cm2となるように負極用スラリーを負極集電体に塗工し、乾燥させて負極を作製した。
次に、正極集電体として厚み15μmのアルミニウム箔(多孔箔)を用い、正極用スラリーを乾燥後の活性炭の質量が4mg/cm2となるように正極集電体に塗工し、乾燥させて正極を作製した。
リチウムイオン電池素子を自己消火性フィルムで包まない以外は、実施例1と同様にしてリチウムイオン電池を作製した。
各実施例における自己消火性フィルムについて、以下のようにして、自己消火層中における消火剤粒子の分散性の確認を行った。
自己消火性フィルムを平面視にて観察し、消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数を確認した。個数は、自己消火性フィルムのうち、一辺10cmの正方形領域あたりの個数に換算して求めた。
得られた結果に基づき、下記評価基準により、自己消火層中における消火剤粒子の分散性を評価した。
結果を表1の「消火剤分散性」欄に示す。
下記評価基準において、自己消火層中における消火剤粒子の分散性に最も優れるランクは、Aである。
A: 消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数が、一辺10cmの正方形領域あたりの個数に換算した場合に、0個であった。
B: 消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数が、一辺10cmの正方形領域あたりの個数に換算した場合に、1個~10個であった。
C: 消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数が、一辺10cmの正方形領域あたりの個数に換算した場合に、10個超であった。
作製したリチウムイオン電池に対し、先端を四角錘に加工した外径が5mmの釘を使用して強制内部短絡試験(釘刺し試験)を行い、リチウムイオン電池表面および内部(釘の先端から5mmの位置)の温度と電圧を測定した。
評価結果を図4及び図5に示す。
「電池表中心(タブ)」はリチウムイオン電池表面の温度、「釘内部(5mm)」は、リチウムイオン電池内部の温度を示す。
自己消火層中の消火剤粒子の分散性と強制内部短絡試験によるリチウムイオン電池内部の最高到達温度とを合わせて表1に示す。
また、熱溶融性結着材粒子の個数平均粒径が0.2μm~2.5μmであると、リチウムイオン電池内部の温度が、電解液の分解温度(およそ180℃)よりも低くなっていることがわかる。これは消火剤粒子の放出性が高く、早期に消火作用を発現したためであると考えられる。
特に、熱溶融性結着材粒子の個数平均粒径が1.0μm以下であり、消火剤粒子と熱溶融性結着材粒子との個数平均粒径が同程度(0.8倍~4倍)であると、セル中温度と融点との差が小さくなっていることから、早期に消火剤粒子が放出されて消火作用を発現していることが確認された。
本明細書に記載された全ての文献、特許出願、及び技術規格は、個々の文献、特許出願、及び技術規格が参照により取り込まれることが具体的かつ個々に記された場合と同程度に、本明細書中に参照により取り込まれる。
Claims (15)
- 熱溶融性結着材と消火剤粒子とを含有する自己消火層を備える、リチウムイオン電池用自己消火性フィルム。
- 前記自己消火層が、前記熱溶融性結着材からなる粒子である熱溶融性結着材粒子を含有する、請求項1に記載のリチウムイオン電池用自己消火性フィルム。
- 前記熱溶融性結着材粒子の個数平均粒径が、0.1μm~6.0μmである、請求項2に記載のリチウムイオン電池用自己消火性フィルム。
- 前記熱溶融性結着材粒子の個数平均粒径が、0.2μm~2.5μmである、請求項2又は請求項3に記載のリチウムイオン電池用自己消火性フィルム。
- 前記熱溶融性結着材粒子は、下記式(1)で求められる平均円形度が0.80以上である、請求項2~請求項4のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。
平均円形度=(粒子投影面積と同じ面積の円の周囲長/粒子投影像の周囲長) … 式(1) - 前記熱溶融性結着材が樹脂であり、
前記樹脂は、JIS K7210-1995に準拠し、温度190℃、荷重21.18Nの条件で測定されたメルトフローレートが20g/10分~55g/10分である、
請求項1~請求項5のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。 - 前記熱溶融性結着材が、ポリオレフィンを含有する、請求項1~請求項6のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。
- 前記消火剤粒子の個数平均粒径が、0.1μm~5.0μmである、請求項1~請求項7のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。
- 更に、粘着材層を備える、請求項1~請求項8のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。
- 更に、
前記自己消火層の一方の面側に配置された粘着材層と、
前記自己消火層の他方の面側に配置された耐燃性層と、
を備える、
請求項1~請求項8のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。 - 平面視した場合に、前記消火剤粒子の凝集物であって直径が0.5mm以上である凝集物の個数が、一辺10cmの正方形領域あたりの個数に換算して10個以下である、請求項1~請求項10のいずれか1項に記載のリチウムイオン電池用自己消火性フィルム。
- 請求項1~請求項11のいずれか1項に記載のリチウムイオン電池用自己消火性フィルムを製造する方法であって、
前記熱溶融性結着材と前記消火剤粒子とを含有する水性分散液Aを準備する工程と、
基材上に前記水性分散液Aを塗布して塗膜を形成する工程と、
前記塗膜を前記熱溶融性結着材の融点未満の温度で加熱乾燥する工程と、
を含むリチウムイオン電池用自己消火性フィルムの製造方法。 - 前記水性分散液Aを準備する工程が、前記熱溶融性結着材からなる粒子である熱溶融性結着材粒子の水分散液と、前記消火剤粒子の水分散液と、を混合する工程を含み、
前記熱溶融性結着材粒子の水分散液のpHが、8.0~11.0である、
請求項12に記載のリチウムイオン電池用自己消火性フィルムの製造方法。 - 正極と、負極と、前記正極及び前記負極の間に介在するセパレータと、
を含むリチウムイオン電池素子と、
請求項1~請求項11のいずれか1項に記載のリチウムイオン電池用自己消火性フィルムと、
を備えるリチウムイオン電池。 - 前記リチウムイオン電池素子の少なくとも一部分と、
前記リチウムイオン電池用自己消火性フィルムの少なくとも一部分と、
が接着されている、請求項14に記載のリチウムイオン電池。
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