JP7377491B2 - Treatment method for positive electrode of non-aqueous electrolyte secondary battery - Google Patents
Treatment method for positive electrode of non-aqueous electrolyte secondary battery Download PDFInfo
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- 239000011255 nonaqueous electrolyte Substances 0.000 title claims description 47
- 238000000034 method Methods 0.000 title claims description 30
- 238000010438 heat treatment Methods 0.000 claims description 65
- 239000000843 powder Substances 0.000 claims description 63
- 239000007789 gas Substances 0.000 claims description 34
- 239000011888 foil Substances 0.000 claims description 25
- 238000000227 grinding Methods 0.000 claims description 22
- 238000006722 reduction reaction Methods 0.000 claims description 20
- 239000011149 active material Substances 0.000 claims description 13
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 239000007769 metal material Substances 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 9
- 238000001465 metallisation Methods 0.000 claims description 8
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- 239000002699 waste material Substances 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 24
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 22
- 239000007774 positive electrode material Substances 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- 239000011572 manganese Substances 0.000 description 13
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- 238000002844 melting Methods 0.000 description 8
- 230000008018 melting Effects 0.000 description 8
- 239000003638 chemical reducing agent Substances 0.000 description 7
- -1 lithium nickel cobalt aluminum Chemical compound 0.000 description 7
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 6
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- 229910052799 carbon Inorganic materials 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
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- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 229910002090 carbon oxide Inorganic materials 0.000 description 4
- 239000004020 conductor Substances 0.000 description 4
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- 230000003647 oxidation Effects 0.000 description 4
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- 229910013100 LiNix Inorganic materials 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000003125 aqueous solvent Substances 0.000 description 3
- 239000003575 carbonaceous material Substances 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 3
- 150000002222 fluorine compounds Chemical class 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
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- 229910052748 manganese Inorganic materials 0.000 description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 3
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
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- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 2
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910010093 LiAlO Inorganic materials 0.000 description 2
- 229910013716 LiNi Inorganic materials 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical compound [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 description 2
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 2
- SOXUFMZTHZXOGC-UHFFFAOYSA-N [Li].[Mn].[Co].[Ni] Chemical compound [Li].[Mn].[Co].[Ni] SOXUFMZTHZXOGC-UHFFFAOYSA-N 0.000 description 2
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- 235000012255 calcium oxide Nutrition 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 239000002482 conductive additive Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
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- 229910001414 potassium ion Inorganic materials 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
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- 239000000126 substance Substances 0.000 description 2
- AJKNNUJQFALRIK-UHFFFAOYSA-N 1,2,3-trifluorobenzene Chemical compound FC1=CC=CC(F)=C1F AJKNNUJQFALRIK-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminium flouride Chemical compound F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 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
- 229910010092 LiAlO2 Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- ZYXUQEDFWHDILZ-UHFFFAOYSA-N [Ni].[Mn].[Li] Chemical compound [Ni].[Mn].[Li] ZYXUQEDFWHDILZ-UHFFFAOYSA-N 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
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- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000000160 carbon, hydrogen and nitrogen elemental analysis Methods 0.000 description 1
- CKFRRHLHAJZIIN-UHFFFAOYSA-N cobalt lithium Chemical compound [Li].[Co] CKFRRHLHAJZIIN-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 150000003949 imides Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- YQNQTEBHHUSESQ-UHFFFAOYSA-N lithium aluminate Chemical compound [Li+].[O-][Al]=O YQNQTEBHHUSESQ-UHFFFAOYSA-N 0.000 description 1
- 229910003473 lithium bis(trifluoromethanesulfonyl)imide Inorganic materials 0.000 description 1
- RSNHXDVSISOZOB-UHFFFAOYSA-N lithium nickel Chemical compound [Li].[Ni] RSNHXDVSISOZOB-UHFFFAOYSA-N 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 description 1
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 description 1
- XVUMPDDKXKGPMS-UHFFFAOYSA-N lithium;trifluoromethylsulfonylazanide Chemical compound [Li+].[NH-]S(=O)(=O)C(F)(F)F XVUMPDDKXKGPMS-UHFFFAOYSA-N 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
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- 229910052751 metal Inorganic materials 0.000 description 1
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- 239000004745 nonwoven fabric Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
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- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- BAZAXWOYCMUHIX-UHFFFAOYSA-M sodium perchlorate Chemical compound [Na+].[O-]Cl(=O)(=O)=O BAZAXWOYCMUHIX-UHFFFAOYSA-M 0.000 description 1
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- 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
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/84—Recycling of batteries or fuel cells
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Description
本発明は、非水電解液二次電池の処理方法に関する。 The present invention relates to a method for treating a non-aqueous electrolyte secondary battery.
リチウムイオン二次電池等の非水電解液二次電池は、ハイブリッド自動車や電気自動車に搭載される電源として用いられている。近年、自動車用の使用済み非水電解液二次電池は、発生量の急激な増大が見込まれている。非水電解液二次電池の電極、特に正極にはニッケル（Ｎｉ）やコバルト（Ｃｏ）等の有価物が含まれている。資源の有効利用のために、非水電解液二次電池から、Ｎｉ、Ｃｏ等の有価物を回収する方法が提案されている。 Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries are used as power sources installed in hybrid vehicles and electric vehicles. In recent years, the amount of used non-aqueous electrolyte secondary batteries for automobiles is expected to increase rapidly. The electrode of a non-aqueous electrolyte secondary battery, particularly the positive electrode, contains valuable materials such as nickel (Ni) and cobalt (Co). In order to effectively utilize resources, methods have been proposed for recovering valuable materials such as Ni and Co from non-aqueous electrolyte secondary batteries.
例えば、特許文献１には、リチウムイオン二次電池から正極を回収し、回収された正極を還元反応に供することにより、Ｎｉおよび／またはＣｏを含有する金属材料を得る方法が開示されている。 For example, Patent Document 1 discloses a method for obtaining a metal material containing Ni and/or Co by collecting a positive electrode from a lithium ion secondary battery and subjecting the collected positive electrode to a reduction reaction.
特許文献１に記載された処理方法では、アルミニウム（Ａｌ）を含む集電箔を還元剤として活用することにより、還元剤を別途追加することなく、還元反応を行っている。ただし、セルから取り出したままの正極は箔状であり、バインダーや導電助剤等が混練されているため反応性が低い。そのため、還元反応を促進させるには、高周波誘導溶解炉等の高温が得られる装置での外部からの加熱や、大量の助燃剤等による反応熱の補助が必要とされており、リサイクルコストが高くなるという課題がある。 In the treatment method described in Patent Document 1, by utilizing a current collector foil containing aluminum (Al) as a reducing agent, a reduction reaction is performed without separately adding a reducing agent. However, the positive electrode taken out from the cell is in the form of a foil and has low reactivity because it is kneaded with a binder, conductive additive, etc. Therefore, in order to promote the reduction reaction, it is necessary to use external heating in a high-temperature device such as a high-frequency induction melting furnace, or to supplement the reaction heat with a large amount of combustion improver, which leads to high recycling costs. There is an issue of becoming.
そこで本発明は、低コストで正極の還元反応を促進させることができる非水電解液二次電池の処理方法を提供することを目的とする。 Therefore, an object of the present invention is to provide a method for treating a non-aqueous electrolyte secondary battery that can promote the reduction reaction of the positive electrode at low cost.
本発明に係る非水電解液二次電池の処理方法は、Ａｌを含む箔と、Ｎｉおよび／またはＣｏを含む金属複合酸化物としての活物質とを有する正極を備える非水電解液二次電池の処理方法であって、前記非水電解液二次電池から前記正極を取り出す取出工程と、前記正極を紛体化して正極紛体を得る紛体化工程と、前記正極紛体を還元反応に供することにより前記Ｎｉおよび／またはＣｏを含有する金属材料を得る金属化工程とを有する。 A method for treating a non-aqueous electrolyte secondary battery according to the present invention provides a non-aqueous electrolyte secondary battery comprising a positive electrode having a foil containing Al and an active material as a metal composite oxide containing Ni and/or Co. The processing method includes a step of taking out the positive electrode from the non-aqueous electrolyte secondary battery, a powdering step of powdering the positive electrode to obtain a positive electrode powder, and subjecting the positive electrode powder to a reduction reaction. and a metallization step to obtain a metal material containing Ni and/or Co.
本発明によれば、正極を紛体化して正極紛体を得る工程と正極紛体を還元反応に供する工程とにしたがって処理するので、低コストで正極の還元反応を促進させることができる。 According to the present invention, the positive electrode is processed through the steps of pulverizing the positive electrode to obtain the positive electrode powder and subjecting the positive electrode powder to a reduction reaction, so that the reduction reaction of the positive electrode can be promoted at low cost.
１．実施形態
以下、図面を参照して本発明の実施形態について詳細に説明する。
1. Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
図１は、本実施形態に係る非水電解液二次電池の処理方法に使用される非水電解液二次電池１０の斜視図である。非水電解液二次電池１０は、電気自動車やハイブリッド自動車等の自動車の電源として利用された使用済みのリチウムイオン二次電池である。以下の説明では非水電解液二次電池１０がリチウムイオン二次電池である場合を例に説明するが、非水電解液二次電池１０としては、リチウムイオン二次電池に限定されず、マグネシウムイオン二次電池、ナトリウムイオン二次電池、カリウムイオン二次電池、カルシウムイオン二次電池等でも良い。なお、非水電解液二次電池１０は、製造後に不良が確認されたリチウムイオン二次電池等の未使用のものでも良い。また、紛体化工程に用いる正極としては正極の製造工程で生じる工程屑等でも良い。
FIG. 1 is a perspective view of a non-aqueous electrolyte
非水電解液二次電池１０は、セル容器１２に、電極体（図示せず）と非水電解液（図示せず）とを備える。セル容器１２は、例えばアルミニウム合金製である。セル容器１２は、容器本体１４および蓋体１６を含む。容器本体１４と蓋体１６とは、レーザー溶接されている。容器本体１４は、有底角筒状に形成されており、内部に電極体と非水電解液とを収容する。蓋体１６は、容器本体１４の開口に設けられ、容器本体１４を密閉する。蓋体１６には、安全弁１８、正極端子２０、および負極端子２２が設けられている。安全弁１８は、非水電解液二次電池１０の内部の圧力を低下させるためのものである。正極端子２０は、正極リード（図示せず）を介して、後述する正極と接続している。負極端子２２は、負極リード（図示せず）を介して、後述する負極と接続している。
The non-aqueous electrolyte
電極体は、セパレータ（図示せず）を介して捲回された正極（図示せず）と負極（図示せず）とを含む。電極体は、上記のような捲回型である場合に限られず、正極、負極、およびセパレータを積層した積層型でも良い。 The electrode body includes a positive electrode (not shown) and a negative electrode (not shown) wound together with a separator (not shown) in between. The electrode body is not limited to the wound type as described above, but may be a laminated type in which a positive electrode, a negative electrode, and a separator are laminated.
正極は、正極集電体および正極活物質層を有する。正極集電体は、本実施形態ではアルミニウム（Ａｌ）を含む箔（以下、Ａｌ箔とも称する）である。正極における正極集電体の質量比は、５～２５質量％である。正極活物質層は、正極活物質、バインダー、および導電材を含む。正極活物質層における導電材、バインダーの質量比は、それぞれ正極の０～３０質量％、０～２０質量％である。 The positive electrode has a positive electrode current collector and a positive electrode active material layer. In this embodiment, the positive electrode current collector is a foil containing aluminum (Al) (hereinafter also referred to as Al foil). The mass ratio of the positive electrode current collector in the positive electrode is 5 to 25% by mass. The positive electrode active material layer includes a positive electrode active material, a binder, and a conductive material. The mass ratio of the conductive material and the binder in the positive electrode active material layer is 0 to 30% by mass and 0 to 20% by mass of the positive electrode, respectively.
正極活物質としては、ニッケル（Ｎｉ）および／またはコバルト（Ｃｏ）を含有する任意の金属複合酸化物を用いることができる。例えば、正極活物質は、リチウムニッケル複合酸化物、リチウムコバルト複合酸化物、リチウムニッケルコバルト複合酸化物、リチウムニッケルマンガン複合酸化物、リチウムニッケルコバルトアルミニウム複合酸化物、リチウムニッケルコバルトマンガン複合酸化物等から選択することができる。本実施形態においては、正極活物質は、リチウムニッケルコバルトマンガン複合酸化物である。なお、正極活物質は、マグネシウムイオン二次電池の場合は任意のマグネシウム複合酸化物を用いることができ、ナトリウムイオン二次電池の場合は任意のナトリウム複合酸化物を用いることができ、カリウムイオン二次電池の場合は任意のカリウム複合酸化物を用いることができ、カルシウムイオン二次電池の場合は任意のカルシウム複合酸化物を用いることができる。 Any metal composite oxide containing nickel (Ni) and/or cobalt (Co) can be used as the positive electrode active material. For example, the positive electrode active material is made of lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, lithium nickel manganese composite oxide, lithium nickel cobalt aluminum composite oxide, lithium nickel cobalt manganese composite oxide, etc. You can choose. In this embodiment, the positive electrode active material is a lithium nickel cobalt manganese composite oxide. As the positive electrode active material, any magnesium composite oxide can be used in the case of a magnesium ion secondary battery, any sodium composite oxide can be used in the case of a sodium ion secondary battery, and potassium ion secondary battery can be used as the positive electrode active material. In the case of a secondary battery, any potassium composite oxide can be used, and in the case of a calcium ion secondary battery, any calcium composite oxide can be used.
バインダーは、ポリフッ化ビニリデン（ＰＶＤＦ）等のフッ素化合物を含むフッ素系バインダーである。導電材は、黒鉛、カーボンブラック等の炭素材料である。 The binder is a fluorine-based binder containing a fluorine compound such as polyvinylidene fluoride (PVDF). The conductive material is a carbon material such as graphite or carbon black.
負極は、負極集電体および負極活物質層を有する。本実施形態においては、負極集電体は銅（Ｃｕ）箔であり、負極活物質は黒鉛である。セパレータとしては、一般的には、ポリエチレン（ＰＥ）、ポリプロピレン（ＰＰ）等の樹脂製の多孔質膜または不織布が用いられる。 The negative electrode has a negative electrode current collector and a negative electrode active material layer. In this embodiment, the negative electrode current collector is copper (Cu) foil, and the negative electrode active material is graphite. As the separator, a porous membrane or nonwoven fabric made of resin such as polyethylene (PE) or polypropylene (PP) is generally used.
非水電解液は、非水溶媒と、この非水溶媒に溶解可能なリチウム塩（電解質）とを含む。非水溶媒としては、カーボネート類、例えば、プロピレンカーボネート（ＰＣ）、エチレンカーボネート（ＥＣ）、ブチレンカーボネート（ＢＣ）、ジメチルカーボネート（ＤＭＣ）、エチルメチルカーボネート（ＥＭＣ）、ジエチルカーボネート（ＤＥＣ）等が用いられる。これらの非水溶媒は、１種類単独又は２種類以上を組み合わせて使用することができる。 The nonaqueous electrolyte includes a nonaqueous solvent and a lithium salt (electrolyte) that can be dissolved in the nonaqueous solvent. As the non-aqueous solvent, carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), etc. are used. It will be done. These non-aqueous solvents can be used singly or in combination of two or more.
電解質としては、フッ素化合物を含むもの、例えば、ＬｉＰＦ６（ヘキサフルオロリン酸リチウム）、ＬｉＢＦ４（テトラフルオロホウ酸リチウム）、ＬｉＴＦＳＡ（リチウムトリフルオロメタンスルホニルアミド）、ＬｉＴＦＳＩ（リチウムビス（トリフルオロメタン）スルホンイミド）等が用いられる。これらの電解質は、１種類単独又は２種類以上を組み合わせて使用することができる。 Examples of electrolytes include those containing fluorine compounds, such as LiPF 6 (lithium hexafluorophosphate), LiBF 4 (lithium tetrafluoroborate), LiTFSA (lithium trifluoromethanesulfonylamide), and LiTFSI (lithium bis(trifluoromethane) sulfone). imide) etc. are used. These electrolytes can be used singly or in combination of two or more.
図２に示すように、非水電解液二次電池１０の処理方法は、取出工程Ｓ１０と紛体化工程Ｓ１１と金属化工程Ｓ１２とを有する。各工程について、それぞれ詳細に説明する。
As shown in FIG. 2, the method for processing the non-aqueous electrolyte
［取出工程］
取出工程Ｓ１０は、非水電解液二次電池１０から正極を取り出す。本実施形態では、セル容器１２を開封して取り出した捲回型の電極体を巻き戻すことにより、帯状の正極を得る。なお、取出工程Ｓ１０では、非水電解液二次電池１０を放電させる放電工程、放電させた非水電解液二次電池１０のセル容器１２内を洗浄液で洗浄するセル内洗浄工程等を行っても良い。
[Removal process]
In the extraction step S10, the positive electrode is extracted from the non-aqueous electrolyte
［紛体化工程］
紛体化工程Ｓ１１は、正極を紛体化して正極紛体を得る。「紛体化」とは、紛体化工程Ｓ１１を経た加熱後の正極を目開きが１ｍｍの篩を用いて篩分けしたときに、上記加熱後かつ篩分け前の正極の質量に対する篩下の紛状物の質量が８０％以上であることをいう。篩下の紛状物が正極紛体である。
[Powderization process]
In the powdering step S11, the positive electrode is powdered to obtain positive electrode powder. "Powderization" means that when the positive electrode after heating through the powderization step S11 is sieved using a sieve with an opening of 1 mm, the powder under the sieve is based on the mass of the positive electrode after heating and before sieving. It means that the mass of is 80% or more. The powder under the sieve is the positive electrode powder.
紛体化工程Ｓ１１は、正極の加熱処理を行う。加熱処理で用いる加熱装置は、例えば、正極が配置される炉と、炉内の温度を検出する温度センサと、炉内を加熱する際の昇温速度を制御する制御部とを有する。 In the powdering step S11, the positive electrode is heated. A heating device used in the heat treatment includes, for example, a furnace in which a positive electrode is placed, a temperature sensor that detects the temperature inside the furnace, and a control unit that controls a temperature increase rate when heating the inside of the furnace.
加熱処理を行う手順を説明する。まず、帯状の正極を耐熱性の容器に配置する。炉を作動させ、炉内を所定の昇温速度で昇温させる。炉内の温度が所定の温度（以下、投入温度と称する）となったときに、正極が配置された容器を炉内に設置する。その後、炉内を、予め設定された温度（以下、加熱温度と称する）まで昇温させ、この加熱温度に維持する。炉内を加熱温度に維持する時間を「温度維持時間」という。なお、正極が配置された容器を炉内に設置してから炉を作動させ、炉内を所定の昇温速度で昇温させても良い。 The procedure for performing heat treatment will be explained. First, a strip-shaped positive electrode is placed in a heat-resistant container. The furnace is operated and the temperature inside the furnace is raised at a predetermined heating rate. When the temperature in the furnace reaches a predetermined temperature (hereinafter referred to as charging temperature), the container in which the positive electrode is placed is placed in the furnace. Thereafter, the temperature inside the furnace is raised to a preset temperature (hereinafter referred to as heating temperature) and maintained at this heating temperature. The time for maintaining the inside of the furnace at the heating temperature is called the "temperature maintenance time." Note that the container in which the positive electrode is placed may be placed in a furnace, and then the furnace may be operated to raise the temperature in the furnace at a predetermined temperature increase rate.
加熱処理後の正極を粉砕して篩分けを行うことにより正極紛体が得られる。正極集電体としてのＡｌ箔は、加熱処理により脆化する。脆化した箔は、炉内に設置されているときは帯状を保っているが、例えば、指で軽く触れるだけで崩れて紛末化し、箔の紛末となる。正極活物質層は、加熱処理によりバインダーが熱分解され、活物質粒子同士の結着および活物質と箔との結着が弱い状態とされる。この状態の正極活物質層が、箔の紛末化に伴い、箔から剥がれて紛末化し、活物質の紛末となる。このため、正極紛体には、箔の紛末と活物質の紛末とが含まれる。 After the heat treatment, the positive electrode is crushed and sieved to obtain positive electrode powder. Al foil as a positive electrode current collector becomes brittle due to heat treatment. The embrittled foil maintains its band shape when placed in the furnace, but if it is lightly touched with a finger, for example, it will crumble and turn into powder, resulting in powdered foil. In the positive electrode active material layer, the binder is thermally decomposed by heat treatment, and the binding between the active material particles and the binding between the active material and the foil is weakened. As the foil is pulverized, the positive electrode active material layer in this state is peeled off from the foil and pulverized to become active material powder. Therefore, the positive electrode powder includes foil powder and active material powder.
なお、紛体化工程Ｓ１１に供される正極は、上記のような帯状のものでも良いし、所定の形状に切断したものでも良い。ただし、正極をシュレッダー等で細かく切断したものを用いると加熱処理中にテルミット反応が起きてしまう場合もあるので、ある程度長尺のものが好ましい。 Note that the positive electrode to be subjected to the powdering step S11 may be a strip-shaped one as described above, or may be one cut into a predetermined shape. However, if the positive electrode is cut into pieces using a shredder or the like, a thermite reaction may occur during the heat treatment, so it is preferable to use a cathode with a certain length.
加熱処理は、大気雰囲気、または、大気雰囲気よりも酸素分圧が低い発生ガス雰囲気で行う。 The heat treatment is performed in an atmospheric atmosphere or a generated gas atmosphere in which the partial pressure of oxygen is lower than that in the atmospheric atmosphere.
大気雰囲気で正極の加熱処理を行う場合について説明する。耐熱性の容器としては燃焼ボート（図示なし）が用いられる。燃焼ボートは、例えばアルミナ（Ａｌ２Ｏ３）により形成されている。なお、耐熱性の容器として、燃焼ボートの代わりに、ルツボや匣鉢等を用いても良い。 A case where the positive electrode is heat-treated in an atmospheric atmosphere will be described. A combustion boat (not shown) is used as a heat-resistant container. The combustion boat is made of, for example, alumina (Al 2 O 3 ). Note that as a heat-resistant container, a crucible, a sagger, or the like may be used instead of the combustion boat.
大気雰囲気で６６０℃以上の加熱温度で正極の加熱処理を行うと、正極集電体の一部のＡｌが大気中の酸素により酸化され、Ａｌ２Ｏ３が生成される。Ａｌ箔は、その一部が酸化されることで脆化する。脆化したＡｌ箔が紛末化することで、酸化したＡｌの紛末と、酸化せずに残ったＡｌ（未反応のＡｌともいう）の紛末とが得られる。アルミニウムの融点である６６０℃以上の加熱温度で正極の加熱処理が行われることにより、Ａｌ箔が融解するとともに、融解したアルミニウムの表面が酸化され、Ａｌ箔の脆化と紛末化とが促進されると考えられる。Ａｌ箔の紛末化により活物質の紛末が得られる。このため、正極紛体には、酸化したＡｌの紛末と、未反応のＡｌの紛末と、活物質の紛末とが含まれる。 When the positive electrode is heat-treated at a heating temperature of 660° C. or higher in the air, a portion of Al in the positive electrode current collector is oxidized by oxygen in the atmosphere, and Al 2 O 3 is generated. Al foil becomes brittle when a part of it is oxidized. By turning the embrittled Al foil into powder, powder of oxidized Al and powder of Al remaining without oxidation (also referred to as unreacted Al) are obtained. By heating the positive electrode at a heating temperature of 660°C or higher, which is the melting point of aluminum, the Al foil melts and the surface of the molten aluminum is oxidized, promoting embrittlement and agglomeration of the Al foil. It is thought that it will be done. A powder of active material is obtained by powdering the Al foil. Therefore, the positive electrode powder includes oxidized Al powder, unreacted Al powder, and active material powder.
紛体化工程Ｓ１１は、大気雰囲気で正極の加熱処理を行う場合、上記のように加熱温度を６６０℃以上とする。加熱温度が低すぎると、正極の紛体化が不十分となる。加熱温度は６８０℃以上であることがより好ましく、７５０℃以上であることが特に好ましい。 In the powdering step S11, when the positive electrode is heat-treated in the air, the heating temperature is set to 660° C. or higher as described above. If the heating temperature is too low, the positive electrode will not be sufficiently pulverized. The heating temperature is more preferably 680°C or higher, particularly preferably 750°C or higher.
大気雰囲気で正極の加熱処理を行う場合の加熱温度は８００℃以下であることが好ましい。加熱温度が高すぎると、正極集電体のＡｌが還元剤となってテルミット反応が起きる場合があり、危険である。 When the positive electrode is heat-treated in the air, the heating temperature is preferably 800° C. or lower. If the heating temperature is too high, Al in the positive electrode current collector may act as a reducing agent and a thermite reaction may occur, which is dangerous.
発生ガス雰囲気で正極の加熱処理を行う場合について説明する。耐熱性の容器としては箱状の蓋付き容器が用いられる。蓋付き容器は、例えばステンレス鋼により形成されている。容器の内部に正極を配置し、容器を蓋で閉じた状態で加熱処理を行う。正極を加熱すると、非水電解液に含まれるカーボネート類の非水溶媒の熱分解およびその後の酸化、バインダーの熱分解およびその後の酸化により、Ｈ２Ｏ、ＣＯ２やＣＯ等の水素や炭素の酸化物のガスが発生する。正極にグラファイト等の炭素材料が導電助剤として含まれている場合には、炭素材料の酸化により炭素の酸化物のガスが発生することもある。また、非水電解液の電解質とバインダーとの少なくともいずれかに含まれるフッ素化合物の熱分解により、フッ化水素（ＨＦ）やトリフルオロベンゼン等のフッ化物のガスが発生する。蓋で閉じられた容器内で正極が加熱されると、上記のような水素や炭素の酸化物のガスやフッ化物のガスの発生により容器内の酸素分圧が低下する。この結果、容器内の酸素分圧は大気の酸素分圧よりも低くなる。このように、水素や炭素の酸化物のガスやフッ化物のガスの発生により酸素分圧が低下した容器内の状態を「発生ガス雰囲気」と称する。水素や炭素の酸化物のガスやフッ化物のガスを「発生ガス」と称する。「発生ガス雰囲気で加熱処理を行う」とは、少なくとも温度維持時間中に容器内が発生ガス雰囲気とされ、この発生ガス雰囲気で加熱処理を行うことをいうものとする。 A case where the positive electrode is heat-treated in a generated gas atmosphere will be described. A box-shaped container with a lid is used as the heat-resistant container. The container with a lid is made of stainless steel, for example. A positive electrode is placed inside the container, and heat treatment is performed with the container closed with a lid. When the positive electrode is heated, hydrogen and carbon such as H 2 O, CO 2 and CO are decomposed due to the thermal decomposition and subsequent oxidation of the non-aqueous solvent of carbonates contained in the non-aqueous electrolyte, and the thermal decomposition and subsequent oxidation of the binder. Oxide gas is generated. When the positive electrode contains a carbon material such as graphite as a conductive additive, carbon oxide gas may be generated due to oxidation of the carbon material. In addition, fluoride gas such as hydrogen fluoride (HF) and trifluorobenzene is generated by thermal decomposition of a fluorine compound contained in at least one of the electrolyte and the binder of the non-aqueous electrolyte. When the positive electrode is heated in a container closed with a lid, the oxygen partial pressure in the container decreases due to the generation of hydrogen, carbon oxide gas, or fluoride gas as described above. As a result, the partial pressure of oxygen within the container is lower than the partial pressure of oxygen in the atmosphere. The state inside the container in which the oxygen partial pressure is reduced due to the generation of hydrogen, carbon oxide gas, or fluoride gas is referred to as a "generated gas atmosphere." Hydrogen and carbon oxide gases and fluoride gases are referred to as "generated gases.""Performing heat treatment in a generated gas atmosphere" means that the inside of the container is made into a generated gas atmosphere at least during the temperature maintenance time, and the heat treatment is performed in this generated gas atmosphere.
発生ガス雰囲気で５８０℃以上の加熱温度で正極の加熱処理を行う場合、酸素分圧が低いので、正極活物質が正極集電体の一部のＡｌにより部分的に還元され、酸化アルミニウムと酸化リチウムとの複合酸化物が生成される反応が起こると考えられる。この反応を「予備還元」という。なお、大気雰囲気で正極の加熱処理を行った場合は、Ａｌが活物質の酸素と反応するよりも先に大気中の酸素と反応するため、予備還元は起こりにくい。 When heat-treating the positive electrode at a heating temperature of 580°C or higher in an atmosphere of generated gas, the oxygen partial pressure is low, so the positive electrode active material is partially reduced by some Al in the positive electrode current collector, and the aluminum oxide and oxidized It is thought that a reaction occurs that produces a composite oxide with lithium. This reaction is called "prereduction." Note that when the positive electrode is heat-treated in an atmospheric atmosphere, preliminary reduction is unlikely to occur because Al reacts with oxygen in the atmosphere before reacting with oxygen in the active material.
正極活物質としてＬｉＮｉｘＣｏｙＭｎｚＯ2を用いた場合を例に挙げて、予備還元について説明する。この場合には、正極活物質の一部で以下のような還元反応が生じる。反応の結果、Ｎｉ、ＣｏおよびＭｎを含有する合金（ＮｉｘＣｏｙＭｎｚ）が得られる。
Ａｌ＋ＬｉＮｉｘＣｏｙＭｎｚＯ2 → ＬｉＡｌＯ2＋ＮｉｘＣｏｙＭｎｚ
Preliminary reduction will be explained by taking as an example a case where LiNix Co y Mn z O 2 is used as the positive electrode active material. In this case, the following reduction reaction occurs in a part of the positive electrode active material. As a result of the reaction, an alloy containing Ni, Co and Mn ( Nix Co y Mn z ) is obtained.
Al+LiNi x Co y Mn z O 2 → LiAlO 2 +Ni x Co y Mn z
予備還元によりアルミン酸リチウム（ＬｉＡｌＯ２）が生成され、Ａｌ箔の一部が酸化されて脆化する。また、発生ガスに含まれるＨＦは、Ａｌと反応した場合にはフッ化アルミニウム（ＡｌＦ３）を生成し、Ａｌ箔をフッ化させて脆化させる。このように、予備還元の他に、発生ガスに含まれる成分もＡｌ箔の脆化に影響しているものと考えられる。 Lithium aluminate (LiAlO 2 ) is generated by the preliminary reduction, and a portion of the Al foil is oxidized and becomes brittle. Furthermore, when HF contained in the generated gas reacts with Al, it produces aluminum fluoride (AlF 3 ), which fluoridates the Al foil and makes it brittle. In this way, in addition to the preliminary reduction, it is thought that the components contained in the generated gas also influence the embrittlement of the Al foil.
発生ガス雰囲気で正極を加熱処理することで得られる正極紛体には、酸化したＡｌの紛末と、未反応のＡｌの紛末と、活物質の紛末とが含まれる他、Ｎｉ、ＣｏおよびＭｎを含有する合金、Ｎｉ、Ｃｏ、およびＭｎの酸化物、ＬｉＡｌＯ２等も含まれる。 The positive electrode powder obtained by heat-treating the positive electrode in a generated gas atmosphere contains oxidized Al powder, unreacted Al powder, and active material powder, as well as Ni, Co, and Also included are alloys containing Mn, oxides of Ni, Co, and Mn, LiAlO2 , and the like.
紛体化工程Ｓ１１は、発生ガス雰囲気で正極の加熱処理を行う場合、上記のように加熱温度を５８０℃以上とする。加熱温度が低すぎると、正極の紛体化が不十分となる。加熱温度は６００℃以上であることがより好ましく、６２０℃以上であることが特に好ましい。 In the powdering step S11, when the positive electrode is heated in the generated gas atmosphere, the heating temperature is set to 580° C. or higher as described above. If the heating temperature is too low, the positive electrode will not be sufficiently pulverized. The heating temperature is more preferably 600°C or higher, particularly preferably 620°C or higher.
発生ガス雰囲気で正極の加熱処理を行う場合の加熱温度は８００℃以下であることが好ましい。加熱温度が高すぎると、正極集電体のＡｌが還元剤となってテルミット反応が起きる場合があり、危険である。 When the positive electrode is heat-treated in a generated gas atmosphere, the heating temperature is preferably 800° C. or lower. If the heating temperature is too high, Al in the positive electrode current collector may act as a reducing agent and a thermite reaction may occur, which is dangerous.
［金属化工程］
金属化工程Ｓ１２は、正極紛体を還元反応に供することによりＮｉおよび／またはＣｏを含有する金属材料を得る。本実施形態では、正極紛体を、還元反応としてのテルミット反応に供する。正極活物質として、ＬｉＮｉｘＣｏｙＭｎｚＯ2を用いた場合を例に挙げて説明する。この場合には、正極紛体に含まれる未反応のＡｌ紛末が還元剤となり、以下のような反応が生じる。反応の結果、Ｎｉおよび／またはＣｏを含有する金属材料として、Ｎｉ、ＣｏおよびＭｎを含有する合金（ＮｉｘＣｏｙＭｎｚ）が得られる。
ＬｉＮｉｘＣｏｙＭｎｚＯ2＋Ａｌ → 1/2Ｌｉ2Ｏ＋ＮｉｘＣｏｙＭｎｚ＋1/2Ａｌ2Ｏ3
[Metalization process]
In the metallization step S12, a metal material containing Ni and/or Co is obtained by subjecting the positive electrode powder to a reduction reaction. In this embodiment, the positive electrode powder is subjected to a thermite reaction as a reduction reaction. An example will be described in which LiNix Co y Mn z O 2 is used as the positive electrode active material. In this case, unreacted Al powder contained in the positive electrode powder becomes a reducing agent, and the following reaction occurs. As a result of the reaction, an alloy containing Ni, Co and Mn (Nix Co y Mn z ) is obtained as a metal material containing Ni and /or Co.
LiNix Co y Mn z O 2 +Al → 1/2Li 2 O+Ni x Co y Mn z +1/2Al 2 O 3
テルミット反応は、大きな発熱を伴う反応であるため、着火により反応が持続する温度に到達した後は自己発熱（反応熱）により反応が進む。このため、正極紛体を容器に入れて着火するだけでテルミット反応が進み、Ｎｉおよび／またはＣｏを含有する金属材料を得ることができる。なお、正極紛体に対し、アルミナを溶融スラグ状態にするためのフラックスや、正極紛体の燃焼を促進するための助燃剤を添加しても良い。高周波誘導溶解炉等の高温が得られる装置を用いて正極紛体を加熱しても良い。例えば、正極紛体１００ｇに対して、フラックスとしての生石灰（ＣａＯ）を０～３０ｇ添加し、助燃剤としての過塩素酸ナトリウム（ＮａＣｌＯ４）を０～３５ｇ添加する。正極紛体とフラックスまたは助燃剤とを加熱装置で溶解して合金化した後、冷却することで、Ｎｉおよび／またはＣｏを含有する金属材料を得ることもできる。 The thermite reaction is a reaction that generates a large amount of heat, so after ignition reaches a temperature at which the reaction continues, the reaction proceeds due to self-heating (reaction heat). Therefore, simply by placing the positive electrode powder in a container and igniting it, the thermite reaction proceeds and a metal material containing Ni and/or Co can be obtained. Incidentally, a flux for turning alumina into a molten slag state and a combustion improver for promoting combustion of the positive electrode powder may be added to the positive electrode powder. The positive electrode powder may be heated using a device capable of obtaining high temperature, such as a high frequency induction melting furnace. For example, 0 to 30 g of quicklime (CaO) as a flux and 0 to 35 g of sodium perchlorate (NaClO 4 ) as a combustion improver are added to 100 g of positive electrode powder. A metal material containing Ni and/or Co can also be obtained by melting and alloying the positive electrode powder and flux or combustion improver with a heating device, and then cooling the mixture.
正極紛体を還元反応としてのテルミット反応に供する場合について説明したが、テルミット反応以外の還元反応により正極紛体からＮｉおよび／またはＣｏを含有する金属材料を得ることができる。例えば、正極紛体と還元剤とを混合し、溶解炉にて溶解して合金化した後、冷却することで、Ｎｉおよび／またはＣｏを含有する金属材料が得られる。 Although the case where the positive electrode powder is subjected to the thermite reaction as a reduction reaction has been described, a metal material containing Ni and/or Co can be obtained from the positive electrode powder by a reduction reaction other than the thermite reaction. For example, a metal material containing Ni and/or Co can be obtained by mixing positive electrode powder and a reducing agent, melting the mixture in a melting furnace to form an alloy, and then cooling the mixture.
２．作用および効果
本実施形態に係る非水電解液二次電池の処理方法は、正極を紛末化して正極紛体を得る紛体化工程Ｓ１１と、正極紛体を還元反応に供する金属化工程Ｓ１２とを有する。正極紛体は、当該正極紛体中の未反応のＡｌ紛末が還元剤となり、また、紛末状であるため反応速度が高速であり、反応熱が急激に発生し、熱が外部に逃げるより先に、反応に必要な温度に到達し、反応が持続する。そのため、大量の助燃剤の使用や高周波誘導溶解炉等の高温が得られる装置を使用することなく、Ａｌの反応熱のみで還元反応が起きる。したがって、本実施形態では、低コストで正極の還元反応を促進させることができる。
2. Actions and Effects The method for treating a non-aqueous electrolyte secondary battery according to the present embodiment includes a powdering step S11 in which a positive electrode is powdered to obtain a positive electrode powder, and a metallization step S12 in which the positive electrode powder is subjected to a reduction reaction. . In the positive electrode powder, the unreacted Al powder in the positive electrode powder acts as a reducing agent, and since it is in powder form, the reaction rate is high, and the reaction heat is rapidly generated, which occurs before the heat escapes to the outside. The temperature required for the reaction is reached and the reaction is sustained. Therefore, the reduction reaction occurs only with the reaction heat of Al without using a large amount of combustion improver or using a device capable of obtaining high temperatures such as a high frequency induction melting furnace. Therefore, in this embodiment, the reduction reaction of the positive electrode can be promoted at low cost.
正極を紛末化することにより嵩密度が向上するので、運搬や保管等のために取り扱う量を増大させることができる。正極紛体は帯状の正極よりも取り扱いが容易である。箔と活物質とを分離する工程が不要となるので、正極をリサイクルする際の歩留まりが向上するとともにコストが低減される。 By pulverizing the positive electrode, the bulk density is improved, so the amount handled for transportation, storage, etc. can be increased. The positive electrode powder is easier to handle than the strip-shaped positive electrode. Since the step of separating the foil and the active material is not necessary, the yield when recycling the positive electrode is improved and the cost is reduced.
紛体化工程Ｓ１１において発生ガス雰囲気で正極の加熱処理を行う場合は、Ａｌの融点である６６０℃よりも低い加熱温度で正極を紛体化できるので、当該加熱処理中のテルミット反応の発生が抑制され、安全性が向上する。また、紛体化工程Ｓ１１で正極集電体の一部のＡｌにより活物質が予備還元されるので、Ａｌ箔を無駄なく活用できていると言える。 When the positive electrode is heat-treated in the generated gas atmosphere in the powdering step S11, the positive electrode can be powdered at a heating temperature lower than 660° C., which is the melting point of Al, so the occurrence of thermite reaction during the heat treatment is suppressed. , safety is improved. Moreover, since the active material is preliminarily reduced by some Al of the positive electrode current collector in the powdering step S11, it can be said that the Al foil can be utilized without wasting it.
紛体化工程Ｓ１１において大気雰囲気で正極の加熱処理を行う場合は、正極紛体中の不要な物質（例えば炭素）を低減することができる。加熱処理前後の正極についてＣＨＮ同時分析を行った結果、加熱処理後に得られる正極紛体は、加熱処理前の正極と比べて、炭素の含有量（質量％）が顕著に減少していた。実際に、加熱処理前の正極の炭素の含有量は５．７質量％であったのに対し、正極紛体の炭素の含有量は０．４質量％であった。正極紛体中の不要な物質が低減することにより、金属化工程Ｓ１２で得られる金属材料の品質の向上が見込める。また、ＣＯ２やＣＯ等のガスが急発生して溶湯が弾け飛ぶ等の危険の抑制が見込める。 When the positive electrode is heat-treated in the air atmosphere in the powdering step S11, unnecessary substances (for example, carbon) in the positive electrode powder can be reduced. Simultaneous CHN analysis of the positive electrode before and after the heat treatment revealed that the carbon content (mass%) of the positive electrode powder obtained after the heat treatment was significantly reduced compared to the positive electrode before the heat treatment. In fact, the carbon content of the positive electrode before heat treatment was 5.7% by mass, while the carbon content of the positive electrode powder was 0.4% by mass. By reducing unnecessary substances in the positive electrode powder, it is expected that the quality of the metal material obtained in the metallization step S12 will be improved. In addition, it is expected that dangers such as the sudden generation of gases such as CO 2 and CO and the explosion of molten metal can be suppressed.
３．実施例
以下に、紛体化工程Ｓ１１により正極が紛末化したか否かを確認するために行った確認実験について説明する。
3. Example Below, a confirmation experiment conducted to confirm whether or not the positive electrode was pulverized in the pulverization step S11 will be described.
［実施例１］～［実施例６］
捲回型の電極体と非水電解液とがセル容器１２に収容された使用済みの非水電解液二次電池を用意した。用意した非水電解液二次電池に含まれる正極と非水電解液の構成は以下の通りである。
[Example 1] to [Example 6]
A used nonaqueous electrolyte secondary battery in which a wound electrode body and a nonaqueous electrolyte were housed in a
正極 Ａｌ箔 厚さ１５μｍ，２０質量％
活物質（ＬｉＮｉ1/6Ｃｏ2/3Ｍｎ1/6Ｏ2） ７２～７３質量％
バインダー（ＰＶＤＦ） ３～４質量％
導電材 ４質量％
非水電解液 非水溶媒（ＤＭＣ：ＥＭＣ：ＰＣ） 質量比２８：２７：２８
電解質（ＬｉＰＦ6） １Ｍ
Positive electrode Al foil thickness 15μm, 20% by mass
Active material (LiNi 1/6 Co 2/3 Mn 1/6 O 2 ) 72-73% by mass
Binder (PVDF) 3-4% by mass
Conductive material 4% by mass
Nonaqueous electrolyte Nonaqueous solvent (DMC:EMC:PC) Mass ratio 28:27:28
Electrolyte (LiPF 6 ) 1M
確認実験では、まず、用意した非水電解液二次電池を放電させ、セル容器１２を開封して取り出した捲回型の電極体を巻き戻すことにより、帯状の正極を得た（取出工程Ｓ１０）。そして、得られた帯状の正極を紛体化工程Ｓ１１に供することにより、確認実験を行った。確認実験の条件と評価結果は表１に示す。
In the confirmation experiment, first, the prepared nonaqueous electrolyte secondary battery was discharged, and the wound electrode body taken out by opening the
帯状の正極を緩く巻いた状態でアルミナ製の角型ルツボに配置し、この角型ルツボを加熱装置の炉内に設置し、正極の加熱処理を行った。すなわち大気雰囲気で正極の加熱処理を行った。大気雰囲気で加熱処理された正極を実施例１～４とした。実施例１～４の正極は、加熱温度を６６０～８００℃の範囲で変更して得られたものである。図３は、大気雰囲気で加熱処理された実施例３の正極の写真である。 The band-shaped positive electrode was placed in a loosely wound state in an alumina square crucible, and the square crucible was placed in a furnace of a heating device to heat the positive electrode. That is, the positive electrode was heat-treated in an air atmosphere. Examples 1 to 4 were positive electrodes that were heat-treated in an air atmosphere. The positive electrodes of Examples 1 to 4 were obtained by changing the heating temperature in the range of 660 to 800°C. FIG. 3 is a photograph of the positive electrode of Example 3 that was heat-treated in an air atmosphere.
帯状の正極を緩く巻いた状態でステンレス製の蓋付き容器内に配置し、容器を蓋で閉じて加熱装置の炉内に設置し、正極の加熱処理を行った。すなわち発生ガス雰囲気で正極の加熱処理を行った。加熱装置は大気雰囲気で加熱処理を行うときに使用するものと同じものである。発生ガス雰囲気で加熱処理された正極を実施例５～６とした。実施例５の正極は加熱温度を５８０℃として得られたものであり、実施例６の正極は加熱温度を６００℃として得られたものである。図４は、発生ガス雰囲気で加熱処理された実施例６の正極の写真である。 The band-shaped positive electrode was placed in a loosely wound state in a stainless steel container with a lid, and the container was closed with a lid and placed in a furnace of a heating device to heat the positive electrode. That is, the positive electrode was heated in an atmosphere of generated gas. The heating device is the same as that used when performing heat treatment in the air. Examples 5 and 6 were positive electrodes that were heat-treated in a generated gas atmosphere. The positive electrode of Example 5 was obtained at a heating temperature of 580°C, and the positive electrode of Example 6 was obtained at a heating temperature of 600°C. FIG. 4 is a photograph of the positive electrode of Example 6 which was heat-treated in a generated gas atmosphere.
実施例１～６の正極について、目開きが１ｍｍの篩を用いて篩分けを行い、篩上および篩下を目視で観察し、正極の紛体化の有無を評価した。「◎」および「〇」は合格であり、「×」は不合格である。 The positive electrodes of Examples 1 to 6 were sieved using a sieve with an opening of 1 mm, and the top and bottom of the sieve were visually observed to evaluate whether or not the positive electrode had become powder. "◎" and "〇" indicate a pass, and "x" indicates a fail.
「◎」：正極の大部分が紛体化した。
「〇」：正極の一部が紛体化した。
「×」：正極が篩上に残留し、ほとんど紛体化しなかった。
"◎": Most of the positive electrode was turned into powder.
“〇”: Part of the positive electrode has turned into powder.
"x": The positive electrode remained on the sieve and was hardly powdered.
［比較例１］～［比較例３］
加熱温度を変えたこと以外は実施例１～４と同じ条件として加熱処理を行った正極を比較例１とした。加熱温度を変えたこと以外は実施例５，６と同じ条件として加熱処理を行った正極を比較例２，３とした。比較例１の正極は、大気雰囲気で加熱温度を６５０℃として得られたものである。比較例２の正極は、発生ガス雰囲気で加熱温度を５００℃として得られたものである。比較例３の正極は、発生ガス雰囲気で加熱温度を５５０℃として得られたものである。比較例１～３について、正極の紛体化の有無を実施例１～６と同じ方法および基準で評価した。図５は、大気雰囲気で加熱処理された比較例１の正極の写真である。
[Comparative Example 1] to [Comparative Example 3]
Comparative Example 1 was a positive electrode that was heat-treated under the same conditions as Examples 1 to 4 except that the heating temperature was changed. Comparative Examples 2 and 3 were positive electrodes that were heat-treated under the same conditions as Examples 5 and 6 except that the heating temperature was changed. The positive electrode of Comparative Example 1 was obtained at a heating temperature of 650° C. in an air atmosphere. The positive electrode of Comparative Example 2 was obtained at a heating temperature of 500° C. in a generated gas atmosphere. The positive electrode of Comparative Example 3 was obtained at a heating temperature of 550° C. in a generated gas atmosphere. For Comparative Examples 1 to 3, the presence or absence of powderization of the positive electrode was evaluated using the same method and criteria as in Examples 1 to 6. FIG. 5 is a photograph of the positive electrode of Comparative Example 1 that was heat-treated in an atmospheric atmosphere.
表１より、大気雰囲気で加熱処理を行った正極である実施例１～４と比較例１とを比べると、比較例１は、正極が紛体化しなかったのに対し、実施例１～４は、正極が紛体化することがわかる。以上から、大気雰囲気で正極の加熱処理を行う場合は加熱温度を６６０℃以上とすることにより正極が紛体化することが確認できた。実施例１～４を比較すると、加熱温度が６６０℃である実施例１よりも、加熱温度が６８０℃以上である実施例２～４の方が、紛体化が良好であることがわかる。 From Table 1, when comparing Examples 1 to 4, which are positive electrodes heat-treated in an atmospheric atmosphere, and Comparative Example 1, it is found that in Comparative Example 1, the positive electrode did not turn into powder, whereas in Examples 1 to 4, the positive electrode did not turn into powder. , it can be seen that the positive electrode becomes powder. From the above, it was confirmed that when the positive electrode is heat-treated in the air, the positive electrode is turned into powder by setting the heating temperature to 660° C. or higher. Comparing Examples 1 to 4, it can be seen that Examples 2 to 4, in which the heating temperature was 680°C or higher, were better in powdering than Example 1, in which the heating temperature was 660°C.
発生ガス雰囲気で加熱処理を行った正極である実施例５，６と比較例２，３とを比べると、比較例２，３は、正極が紛体化しなかったのに対し、実施例５，６は、正極が紛体化することがわかる。以上から、発生ガス雰囲気で正極の加熱処理を行う場合は加熱温度を５８０℃以上とすることにより正極が紛体化することが確認できた。実施例５，６を比較すると、加熱温度が５８０℃である実施例５よりも、加熱温度が６００℃である実施例６の方が、紛体化が良好であることがわかる。 Comparing Examples 5 and 6, which were positive electrodes that were heat-treated in a generated gas atmosphere, and Comparative Examples 2 and 3, it was found that in Comparative Examples 2 and 3, the positive electrodes did not turn into powder, whereas in Examples 5 and 6, the positive electrodes did not turn into powder. It can be seen that the positive electrode becomes powder. From the above, it was confirmed that when the positive electrode is heat-treated in a generated gas atmosphere, the positive electrode is turned into powder by setting the heating temperature to 580° C. or higher. Comparing Examples 5 and 6, it can be seen that Example 6, in which the heating temperature was 600°C, was better in powdering than Example 5, in which the heating temperature was 580°C.
本発明は上記実施形態に限定されるものではなく、本発明の趣旨の範囲内で適宜変更することが可能である。 The present invention is not limited to the embodiments described above, and can be modified as appropriate within the scope of the spirit of the present invention.
１０ 非水電解液二次電池
Ｓ１０ 取出工程
Ｓ１１ 紛体化工程
Ｓ１２ 金属化工程
10 Nonaqueous electrolyte secondary battery S10 Removal process S11 Powderization process S12 Metalization process
Claims (5)
前記正極の加熱処理を行い、前記正極を紛体化して正極紛体を得る紛体化工程と、
前記正極紛体を還元反応に供することにより前記Ｎｉおよび／またはＣｏを含有する金属材料を得る金属化工程と
を有する非水電解液二次電池の正極の処理方法。 A method for treating a positive electrode of a non-aqueous electrolyte secondary battery comprising a positive electrode having a foil containing Al and an active material as a metal composite oxide containing Ni and/or Co, the method comprising:
A powdering step of heating the positive electrode and powdering the positive electrode to obtain a positive electrode powder;
A method for treating a positive electrode of a non-aqueous electrolyte secondary battery, comprising: a metallization step of subjecting the positive electrode powder to a reduction reaction to obtain the metal material containing Ni and/or Co.
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