Binders, electrode compounds, electrodes, and non-aqueous electrolyte batteries for non-aqueous electrolyte batteries

Abstract

The present invention provides a binder for non-aqueous electrolyte batteries, which contains a polymer comprising a segment A having a glass transition temperature below 25°C and a segment B having a melting point above 50°C.

Description

Technical Field

[0001] The present invention relates to a binder for non-aqueous electrolyte batteries, an electrode binder, an electrode, and a non-aqueous electrolyte battery. Prior Art

[0002] Patent Document 1 describes a slurry for an electrode binder of a lithium secondary battery, which contains an electrode active material (A), a binder (B), and fluororubber particles (C).

[0003] Patent Document 2 describes a binder containing a fluoropolymer, characterized in that the fluoropolymer contains a polymerization unit based on vinylidene fluoride and a polymerization unit based on a monomer having an amide group (-CO-NRR' (R and R' are the same or different and each represents a hydrogen atom or an alkyl group which may have a substituent)) or an amide bond (-CO-NR" - (R" represents a hydrogen atom, an alkyl group which may have a substituent, or a phenyl group which may have a substituent)), and the solution viscosity is 10 to 20,000 mPa·s.

[0004] Patent Document 3 describes a binder for a battery containing a fluorine-containing copolymer. The fluorine-containing copolymer contains a repeating unit (a) based on vinylidene fluoride and at least one repeating unit (b) selected from the group consisting of repeating unit (b1) and repeating unit (b2). The repeating unit (b1) is represented by the general formula (b1): -(CH2 - CFRf1)- (wherein, Rf1 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and when the carbon number is 2 or more, it may contain an oxygen atom between carbon-carbon atoms), and the repeating unit (b2) is represented by the general formula (b2): -(CHF - CHRf2)- (wherein, Rf2 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and when the carbon number is 2 or more, it may contain an oxygen atom between carbon-carbon atoms). In the fluorine-containing copolymer, the molar ratio of repeating unit (a) to repeating unit (b) ((a) / (b)) is 95 / 5 to 5 / 95. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. WO2011 / 002097 [Patent Document 2] Japanese Patent Application Laid-Open No. JP2013 - 219016 [Patent Document 3] International Publication No. WO2022 / 039260 Summary of the Invention

[0006] [Problems to be Solved by the Invention] An object of the present invention is to provide a binder for a non-aqueous electrolyte battery capable of forming an electrode material layer excellent in flexibility and toughness. [Technical Means for Solving the Problems]

[0007] According to the present invention, there can be provided a binder for a non-aqueous electrolyte battery, which contains a polymer including a segment A having a glass transition temperature of 25°C or lower and a segment B having a melting point of 50°C or higher. [Effects of the Invention]

[0008] According to the present invention, there can be provided a binder for a non-aqueous electrolyte battery capable of forming an electrode material layer excellent in flexibility and toughness. Embodiments

[0009] Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0010] A wound non-aqueous electrolyte battery is manufactured by sandwiching a separator between a positive electrode and a negative electrode and winding them. When winding, since a bending stress is applied to the electrode material layer of the electrode, the binder for forming the electrode material layer is required to have the following properties, that is, it can provide an electrode material layer excellent in flexibility and capable of withstanding the bending stress. Here, as a binder capable of forming an electrode material layer showing sufficient flexibility, a binder containing a fluorine-containing copolymer is proposed in Patent Document 3, which contains a repeating unit (a) having a specific structure and a repeating unit (b) having a specific structure in an extremely limited molar ratio.

[0011] Even when the electrode material layer formed using the binder described in Patent Document 3 is tightened and wound at the same time, it has sufficient flexibility such that it does not break. On the other hand, in a manufacturing method of a part of a wound battery, there is a case where a separator is sandwiched between a positive electrode and a negative electrode, a certain tension is applied to them, and winding is performed at the same time. When using this manufacturing method, the electrode material layer is not only given a bending stress but also a tension. The present inventors have found that if the electrode material layer used in this manufacturing method can be given not only flexibility but also toughness, a battery showing higher performance can be manufactured.

[0012] The binder for non-aqueous electrolyte batteries of the present invention has been developed in view of such a situation. By using the binder for non-aqueous electrolyte batteries of the present invention, an electrode material layer excellent in flexibility and toughness can be formed.

[0013] In the present invention, regarding the flexibility and toughness of the electrode material layer, for example, it can be confirmed by performing a three-point bending test on the electrode having the electrode material layer. The electrode material layer of the electrode having a smaller maximum test force measured by the three-point bending test is considered to be excellent in flexibility. Also, the electrode material layer of the electrode having a larger half-width measured by the three-point bending test is considered to be excellent in toughness. Regarding the half-width, it can be specified as follows: Using the result of the three-point bending test of the electrode, a curve is plotted with the stroke of the autograph as the horizontal axis and the stress as the vertical axis, and it is specified as the peak width at half of the peak of the stress.

[0014] That is, according to the present invention, there is provided a binder for non-aqueous electrolyte batteries (hereinafter, in some cases referred to as the first binder for non-aqueous electrolyte batteries), which contains a polymer, and the polymer includes a segment A having a glass transition temperature of 25°C or lower and a segment B having a melting point of 50°C or higher.

[0015] Also, according to the present invention, there is provided a binder for non-aqueous electrolyte batteries (hereinafter, in some cases referred to as the second binder for non-aqueous electrolyte batteries), which contains a polymer, the above polymer has a glass transition temperature and a melting point, contains 2,3,3,3-tetrafluoropropene units, and the extraction amount with tetrahydrofuran at 25°C is 5% by mass or less.

[0016] In the present invention, the non-aqueous electrolyte means a liquid non-aqueous electrolyte, which is distinguished from solid electrolytes such as polymer electrolytes and inorganic solid electrolytes.

[0017] First, the constitution of the first binder for non-aqueous electrolyte batteries will be described in detail.

[0018] 1. First binder for non-aqueous electrolyte batteries The first binder for non-aqueous electrolyte batteries contains a polymer including segment A and segment B. As long as the polymer includes segment A and segment B, it may also include other segments having a constitution different from segment A and segment B.

[0019] (Segment A of the polymer) Segment A has a glass transition temperature of 25°C or lower. The glass transition temperature of segment A is preferably 0°C or lower, more preferably -5°C or lower, and even more preferably -10°C or lower. The binder for the first non-aqueous electrolyte battery contains: a polymer including segment A having a glass transition temperature, and thus can form an electrode material layer with excellent flexibility.

[0020] The glass transition temperature can be determined by the following method: using a differential scanning calorimeter (DSC822e manufactured by Mettler-Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science), cooling 10 mg of the sample to -75°C and then heating it at a rate of 20°C per minute to obtain a DSC curve, and taking the temperature of the intersection of the extension line of the baseline before and after the second transition of the DSC curve and the tangent line at the inflection point of the DSC curve as the glass transition temperature.

[0021] Regarding the heat of fusion of segment A, in terms of further improving the flexibility of the electrode material layer, it is preferably less than 5 J / g, more preferably less than 3 J / g, and even more preferably less than 2 J / g.

[0022] Regarding the heat of fusion, a differential scanning calorimetry (DSC) device can be used to heat the sample from 30°C to 220°C at a rate of 10°C per minute, and it is calculated based on the magnitude of the melting peak (ΔH) of the obtained endothermic curve. When the polymer does not show a distinct melting peak, the polymer has no heat of fusion, that is, the heat of fusion of the polymer is 0 J / g.

[0023] Segment A can be a segment that does not show a distinct melting point.

[0024] Regarding segment A, in terms of improving the electrolyte resistance of the electrode material layer, it preferably contains fluorine-containing monomer units. As the fluorine-containing monomer that can constitute segment A, there is no particular limitation as long as it is a monomer containing a fluorine atom, and examples include: vinylidene fluoride [VdF], trifluoroethylene, tetrafluoroethylene [TFE], hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, vinyl fluoride, a monomer providing a repeating unit represented by the following general formula (b1), a monomer providing a repeating unit represented by the following general formula (b2), etc.

[0025] The content of the fluorine-containing monomer units in segment A is preferably 50 mol% or more, more preferably 90 mol% or more, still more preferably 99 mol% or more, and preferably 100 mol% or less, and may also be 100 mol%, relative to all the monomer units constituting segment A.

[0026] Segment A may further contain non-fluorine-containing monomer units. Examples of the non-fluorine-containing monomer include ethylene, propylene, alkyl vinyl ether, etc. The content of the non-fluorine-containing monomer units is preferably 0 to 50 mol%, more preferably 0 to 10 mol%, still more preferably 0 to 1 mol%, and may also be 0 mol%, relative to all the monomer units constituting segment A.

[0027] Segment A may further contain units based on monomers having reactive groups such as cyano group, carboxyl group, alkoxycarbonyl group, I, Br, -CH2OH, and carbon-carbon double bond. The content of the units based on the monomers having reactive groups is preferably 0 to 50 mol%, more preferably 0 to 10 mol%, still more preferably 0 to 1 mol%, and may also be 0 mol%, relative to all the monomer units constituting segment A.

[0028] In the present invention, the content of each monomer unit can be measured by the NMR method.

[0029] Segment A preferably contains at least VdF unit or TFE unit, and more preferably contains at least VdF unit as the fluorine-containing monomer unit. By making segment A contain VdF unit, the glass transition temperature of segment A can be easily adjusted within the desired range, and the flexibility of the electrode material layer can be further improved. Also, by making segment A contain VdF unit, the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide can be improved.

[0030] The content of the VdF units in segment A is preferably 99 to 15 mol%, more preferably 94 mol% or less, still more preferably 88 mol% or less, still more preferably 82 mol% or less, particularly preferably 80 mol% or less, and more preferably 22 mol% or more, still more preferably 50 mol% or more, still more preferably 60 mol% or more, particularly preferably 70 mol% or more, relative to all the monomer units constituting segment A.

[0031] Regarding segment A, in terms of further improving the flexibility of the electrode material layer and further improving the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide, it is more preferably to contain a VdF unit and at least one selected from the group consisting of repeating units represented by any of the following formulas. Formula: -CF 2-CF[-CF 3]- General formula (b1): -CH 2-CFRf 1- (In the formula, Rf 1 is a linear or branched fluoroalkyl or fluoroalkoxy group having 1 to 12 carbon atoms, and when the number of carbon atoms is 2 or more, it may contain an oxygen atom between carbon-carbon atoms); General formula (b2): -CHF-CHRf 2- (In the formula, Rf 2 is a linear or branched fluoroalkyl or fluoroalkoxy group having 1 to 12 carbon atoms, and when the number of carbon atoms is 2 or more, it may contain an oxygen atom between carbon-carbon atoms).

[0032] The content of at least one unit selected from the group consisting of repeating units represented by any of the above formulas in segment A is preferably 1 to 85 mol% relative to all monomer units constituting segment A, more preferably 6 mol% or more, still more preferably 12 mol% or more, still more preferably 18 mol% or more, particularly preferably 20 mol% or more, and more preferably 78 mol% or less, still more preferably 50 mol% or less, still more preferably 40 mol% or less, particularly preferably 30 mol% or less.

[0033] The repeating unit represented by the formula: -CF 2-CF[-CF 3]- is a repeating unit based on hexafluoropropylene. Therefore, in one embodiment, segment A contains a VdF unit and a hexafluoropropylene unit.

[0034] In the general formula (b1): -CH 2-CFRf 1-, Rf 1 is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms or a linear or branched fluoroalkoxy group having 1 to 12 carbon atoms. Both the fluoroalkyl group and the fluoroalkoxy group may contain an oxygen atom (-O-) between carbon-carbon atoms when the number of carbon atoms is 2 or more.

[0035] The fluoroalkyl group of Rf 1 may be a partially fluorinated alkyl group in which a part of the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms, or a perfluorinated alkyl group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. Also, regarding the fluoroalkyl group of Rf 1, its hydrogen atoms may be replaced by substituents other than fluorine atoms, but it is preferably free of substituents other than fluorine atoms.

[0036] The fluoroalkoxy group of Rf 1 may be a partially fluorinated alkoxy group in which some of the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms, or a perfluorinated alkoxy group in which all of the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. Also, regarding the fluoroalkoxy group of Rf 1, the hydrogen atoms thereof may be replaced by substituents other than fluorine atoms, but preferably do not contain substituents other than fluorine atoms.

[0037] The number of carbon atoms of Rf 1 is preferably 1 to 10, more preferably 1 to 6, still more preferably 1 to 4, and particularly preferably 1.

[0038] As Rf 1, a group represented by the following general formula is preferred: -(Rf 11) m-(O) p-(Rf 12-O) n-Rf 13 (In the formula, Rf 11 and Rf 12 are independently a linear or branched fluoroalkylene group having 1 to 4 carbon atoms, Rf 13 is a linear or branched fluoroalkyl group having 1 to 4 carbon atoms, p is 0 or 1, m is an integer of 0 to 4, and n is an integer of 0 to 4).

[0039] The fluoroalkylene groups of Rf 11 and Rf 12 may be a partially fluorinated alkylene group in which some of the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms, or a perfluorinated alkylene group in which all of the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. Also, regarding the fluoroalkylene groups of Rf 11 and Rf 12, the hydrogen atoms thereof may be replaced by substituents other than fluorine atoms, but preferably do not contain substituents other than fluorine atoms. When Rf 11 and Rf 12 appear respectively, they may be the same or different.

[0040] Examples of the perfluoroalkylene group for Rf 11 include: -CHF-, -CF 2-, -CH 2-CF 2-, -CHF-CF 2-, -CF 2-CF 2-, -CF(CF 3)-, -CH 2-CF 2-CF 2-, -CHF-CF 2-CF 2-, -CF 2-CF 2-CF 2-, -CF(CF 3)-CF 2-, -CF 2-CF(CF 3)-, -C(CF 3) 2-, -CH 2-CF 2-CF 2-CF 2-, -CHF-CF 2-CF 2-CF 2-, -CF 2-CF 2-CF 2-CF 2-, -CH(CF 3)-CF 2-CF 2-, -CF(CF 3)-CF 2-CF 2-, -C(CF 3) 2-CF 2-, etc. Among them, a perfluoroalkylene group having 1 or 2 carbon atoms is preferred, and -CF 2- is more preferred.

[0041] Examples of the perfluoroalkylene group for Rf 12 include: -CHF-, -CF 2-, -CH 2-CF 2-, -CHF-CF 2-, -CF 2-CF 2-, -CF(CF 3)-, -CH 2-CF 2-CF 2-, -CHF-CF 2-CF 2-, -CF 2-CF 2-CF 2-, -CF(CF 3)-CF 2-, -CF 2-CF(CF 3)-, -C(CF 3) 2-, -CH 2-CF 2-CF 2-CF 2-, -CHF-CF 2-CF 2-CF 2-, -CF 2-CF 2-CF 2-CF 2-, -CH(CF 3)-CF 2-CF 2-, -CF(CF 3)-CF 2-CF 2-, -C(CF 3) 2-CF 2-, etc. Among them, a perfluoroalkylene group having 1 to 3 carbon atoms is preferred, and -CF 2-, -CF 2CF 2-, -CF 2-CF 2-CF 2-, -CF(CF 3)-CF 2- or -CF 2-CF(CF 3)- is more preferred.

[0042] The fluoroalkyl group for Rf 13 can be a partially fluorinated alkyl group in which some of the hydrogen atoms bonded to the carbon atoms are replaced by fluorine atoms, or a perfluoroalkyl group in which all of the hydrogen atoms bonded to the carbon atoms are replaced by fluorine atoms. Further, regarding the fluoroalkyl group for Rf 13, the hydrogen atoms can also be replaced by substituents other than fluorine atoms, but it is preferably free of substituents other than fluorine atoms (e.g., reactive functional groups such as -CN, -I, -Br, etc.).

[0043] Examples of the fluoroalkyl group for Rf13 include: -CH2F, -CHF2, -CF3, -CH2-CH2F, -CH2-CHF2, -CH2-CF3, -CHF-CH2F, -CHF-CHF2, -CHF-CF3, -CF2-CH2F, -CF2-CHF2, -CF2-CF3, -CH2-CF2-CH2F, -CHF-CF2-CH2F, -CF2-CF2-CH2F, -CF(CF3)-CH2F, -CH2-CF2-CHF2, -CHF-CF2-CHF2, -CF2-CF2-CHF2, -CF(CF3)-CHF2, -CH2-CF2-CF3, -CHF-CF2-CF3, -CF2-CF2-CF3, -CF(CF3)-CF3, -CH2-CF2-CF2-CF3, -CHF-CF2-CF2-CF3, -CF2-CF2-CF2-CF3, -CH(CF3)-CF2-CF3, -CF(CF3)-CF2-CF3, -C(CF3)2-CF3, etc. Among them, preferred are: -CF3, -CHF-CF3, -CF2-CHF2, -CF2-CF3, -CF2-CF2-CF3, -CF(CF3)-CF3, -CF2-CF2-CF2-CF3, -CH(CF3)-CF2-CF3 or -CF(CF3)-CF2-CF3.

[0044] As p, 0 is preferred.

[0045] As m, an integer of 0 to 2 is preferred, more preferably 0 or 1, and even more preferably 0. Also, when p is 0, m is also preferably 0.

[0046] As n, an integer of 0 to 2 is preferred, more preferably 0 or 1, and even more preferably 0.

[0047] As the repeating unit represented by the general formula (b1), preferred are: -CH2-CF[-CF3]-, -CH2-CF[-CF2CF3]-, -CH2-CF[-CF2CF2CF3]-, -CH 2-CF[-CF 2CF 2CF 2CF 3]-, -CH 2-CF[-CF 2-O-CF(CF 3)-CF 2-O-CHF-CF 3]-, -CH 2-CF[-CF 2-O-CF(CF 3)-CF 2-O-CF 2-CF 3]-, -CH 2-CF[-CF 2-O-CF(CF 3)-CF 2-O-CF(CF 3)-CF 3]-, -CH 2-CF[-CF 2-O-CF(CF 3)-CF 2-O-CH(CF 3)-CF 2-CF 3]-, -CH 2-CF[-CF 2-O-CF(CF 3)-CF 2-O-CF(CF 3)-CF 2-CF 3]-, -CH 2-CF[-OCF 2OCF 3]-, -CH 2-CF[-OCF 2CF 2CF 2OCF 3]-, -CH 2-CF[-CF 2OCF 2OCF 3]-, -CH 2-CF[-CF 2OCF 2CF 2CF 2OCF 3]-or -CH2-CF[-O-CF2-CF3]-, Better: -CH2-CF[-CF3]- or -CH 2-CF[-CF 2-O-CF(CF 3)-CF 2-O-CHF-CF 3]-.

[0048] In the general formula (b2): -CHF-CHRf2-, Rf2 is a linear or branched fluorinated alkyl group having 1 to 12 carbon atoms, or a linear or branched fluorinated alkoxy group having 1 to 12 carbon atoms. When the fluorinated alkyl group and the fluorinated alkoxy group both have 2 or more carbon atoms, they may contain an oxygen atom (-O-) between carbon atoms.

[0049] The fluorinated alkyl group of Rf2 may be a partially fluorinated alkyl group in which a part of the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms, or may be a perfluorinated alkyl group in which all the hydrogen atoms bonded to the carbon atom are replaced by fluorine atoms. In addition, regarding the fluorinated alkyl group of Rf2, its hydrogen atom may be substituted by a substituent other than a fluorine atom, but preferably does not contain a substituent other than a fluorine atom.

[0050] The fluoroalkoxy group of Rf 2 may be a partially fluorinated alkoxy group in which a part of the hydrogen atoms bonded to the carbon atom is replaced by a fluorine atom, or a perfluorinated alkoxy group in which all of the hydrogen atoms bonded to the carbon atom are replaced by a fluorine atom. Further, regarding the fluoroalkoxy group of Rf 2, the hydrogen atoms thereof may be replaced by substituents other than fluorine atoms, but preferably do not contain substituents other than fluorine atoms.

[0051] The carbon number of Rf 2 is preferably 1 to 10, more preferably 1 to 6, still more preferably 1 to 4, and particularly preferably 1.

[0052] As Rf 2, a group represented by the following general formula is preferred: -(Rf 21) m-(O) p-(Rf 22-O) n-Rf 23 (In the formula, Rf 21 and Rf 22 are independently a linear or branched fluoroalkylene group having 1 to 4 carbon atoms, Rf 23 is a linear or branched fluoroalkyl group having 1 to 4 carbon atoms, p is 0 or 1, m is an integer of 0 to 4, and n is an integer of 0 to 4).

[0053] The fluoroalkylene groups of Rf 21 and Rf 22 may be partially fluorinated alkylene groups in which a part of the hydrogen atoms bonded to the carbon atom is replaced by a fluorine atom, or perfluorinated alkylene groups in which all of the hydrogen atoms bonded to the carbon atom are replaced by a fluorine atom. Further, regarding the fluoroalkylene groups of Rf 21 and Rf 22, the hydrogen atoms thereof may be replaced by substituents other than fluorine atoms, but preferably do not contain substituents other than fluorine atoms. When Rf 21 and Rf 22 appear respectively, they may be the same or different.

[0054] Examples of the fluoroalkylene group of Rf 21 include: -CHF-, -CF 2-, -CH 2-CF 2-, -CHF-CF 2-, -CF 2-CF 2-, -CF(CF 3)-, -CH 2-CF 2-CF 2-, -CHF-CF 2-CF 2-, -CF 2-CF 2-CF 2-, -CF(CF 3)-CF 2-, -CF 2-CF(CF 3)-, -C(CF 3) 2-, -CH 2-CF 2-CF 2-CF 2-, -CHF-CF 2-CF 2-CF 2-, -CF 2-CF 2-CF 2-CF 2-, -CH(CF 3)-CF 2-CF 2-, -CF(CF 3)-CF 2-CF 2-, -C(CF 3) 2-CF 2-, etc. Among them, a perfluorinated alkylene group having 1 or 2 carbon atoms is preferred, and -CF 2- is more preferred.

[0055] Examples of the fluoroalkylene group as Rf 22 include: -CHF-, -CF 2-, -CH 2-CF 2-, -CHF-CF 2-, -CF 2-CF 2-, -CF(CF 3)-, -CH 2-CF 2-CF 2-, -CHF-CF 2-CF 2-, -CF 2-CF 2-CF 2-, -CF(CF 3)-CF 2-, -CF 2-CF(CF 3)-, -C(CF 3) 2-, -CH 2-CF 2-CF 2-CF 2-, -CHF-CF 2-CF 2-CF 2-, -CF 2-CF 2-CF 2-CF 2-, -CH(CF 3)-CF 2-CF 2-, -CF(CF 3)-CF 2-CF 2-, -C(CF 3) 2-CF 2-, etc. Among them, a perfluoroalkylene group having 1 to 3 carbon atoms is preferred, and -CF 2-, -CF 2CF 2-, -CF 2-CF 2-CF 2-, -CF(CF 3)-CF 2- or -CF 2-CF(CF 3)- is more preferred.

[0056] The fluoroalkyl group as Rf 23 can be a partially fluorinated alkyl group in which a part of the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms, or a perfluoroalkyl group in which all the hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. Further, regarding the fluoroalkyl group of Rf 23, its hydrogen atoms can also be replaced by substituents other than fluorine atoms, but it is preferably free of substituents other than fluorine atoms (for example, reactive functional groups such as -CN, -I, -Br, etc.).

[0057] Examples of the fluoroalkyl group as Rf 23 include: -CH 2F, -CHF 2, -CF 3, -CH 2-CH 2F, -CH 2-CHF 2, -CH 2-CF 3, -CHF-CH 2F, -CHF-CHF 2, -CHF-CF 3, -CF 2-CH 2F, -CF 2-CHF 2, -CF 2-CF 3, -CH 2-CF 2-CH 2F, -CHF-CF 2-CH 2F, -CF 2-CF 2-CH 2F, -CF(CF 3)-CH 2F, -CH 2-CF 2-CHF 2, -CHF-CF 2-CHF 2, -CF 2-CF 2-CHF 2, -CF(CF 3)-CHF 2, -CH 2-CF 2-CF 3, -CHF-CF 2-CF 3, -CF 2-CF 2-CF 3, -CF(CF 3)-CF 3, -CH 2-CF 2-CF 2-CF 3, -CHF-CF 2-CF 2-CF 3, -CF 2-CF 2-CF 2-CF 3, -CH(CF 3)-CF 2-CF 3, -CF(CF 3)-CF 2-CF 3, -C(CF 3) 2-CF 3, etc. Among them, preferred are: -CF 3, -CHF-CF 3, -CF 2-CHF 2, -CF 2-CF 3, -CF 2-CF 2-CF 3, -CF(CF 3)-CF 3, -CF 2-CF 2-CF 2-CF 3, -CH(CF 3)-CF 2-CF 3 or -CF(CF 3)-CF 2-CF 3.

[0058] As p, 0 is preferred.

[0059] As m, an integer of 0 to 2 is preferred, more preferably 0 or 1, and still more preferably 0. Further, when p is 0, m is also preferably 0.

[0060] As n, an integer of 0 to 2 is preferred, more preferably 0 or 1, and still more preferably 0.

[0061] As the repeating unit represented by the general formula (b2), preferred are: -CHF-CH[-CF 3]-, -CHF-CH[-CF 2CF 3]-, -CHF-CH[-CF 2CF 2CF 3]- or -CHF-CH[-CF 2CF 2CF 2CF 3]-, More preferably -CHF-CH[-CF 3]-.

[0062] Among them, segment A preferably contains VdF units and 2,3,3,3-tetrafluoropropene units. By making segment A contain VdF units and 2,3,3,3-tetrafluoropropene units, the flexibility of the electrode material layer can be further improved, and an electrode binder with excellent viscosity stability can be obtained. Also, the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide can be improved.

[0063] The content of 2,3,3,3-tetrafluoropropene units in segment A is preferably 1 to 85 mol%, more preferably 6 mol% or more, still more preferably 12 mol% or more, still more preferably 18 mol% or more, particularly preferably 20 mol% or more, and more preferably 78 mol% or less, still more preferably 50 mol% or less, still more preferably 40 mol% or less, particularly preferably 30 mol% or less, relative to all monomer units constituting segment A.

[0064] In one embodiment, segment A can be formed by a 2,3,3,3-tetrafluoropropene / VdF copolymer or a 2,3,3,3-tetrafluoropropene / VdF / TFE copolymer.

[0065] In the 2,3,3,3-tetrafluoropropene / VdF copolymer, the composition (mol%) of 2,3,3,3-tetrafluoropropene units / VdF units is preferably (18~40) / (82~60), more preferably (20~30) / (80~70).

[0066] In the 2,3,3,3-tetrafluoropropene / VdF / TFE copolymer, the composition (mol%) of 2,3,3,3-tetrafluoropropene units / VdF units / TFE units is preferably (18~40) / (81~25) / (1~35), more preferably (20~40) / (75~30) / (5~30).

[0067] In one embodiment, segment A of the polymer contains 2,3,3,3-tetrafluoropropene units and VdF units. The content of monomer units other than 2,3,3,3-tetrafluoropropene units and VdF units is preferably 0 to 10 mol%, more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, still more preferably 0 to 0.1 mol%, and particularly preferably 0 mol% with respect to all monomer units constituting segment A. The content of 2,3,3,3-tetrafluoropropene units and the content of VdF units may be within the above ranges.

[0068] (Segment B of the polymer) Segment B has a melting point of 50°C or higher. The melting point of segment B is preferably 90°C or higher, more preferably 140°C or higher, and preferably 240°C or lower, more preferably 220°C or lower, still more preferably 200°C or lower. Since the binder for the first non-aqueous electrolyte battery contains a polymer including segment A having a glass transition temperature and segment B having a melting point, an electrode material layer excellent in flexibility and toughness can be formed.

[0069] Regarding the melting point, a differential scanning calorimetry (DSC) apparatus can be used. The sample is heated from 30°C to 220°C at a rate of 10°C / minute, and the temperature at the peak of the obtained endothermic curve is determined as the melting point.

[0070] Generally, the melting point of segment B is the same as the melting point of the first polymer. Therefore, by measuring the melting point of the first polymer, the melting point of segment B in the first polymer can be determined.

[0071] Regarding the heat of fusion of segment B, in terms of further improving the flexibility and toughness of the electrode material layer, it is preferably 5 J / g or more, more preferably 10 J / g or more, still more preferably 30 J / g or more, still more preferably 35 J / g or more, and preferably 90 J / g or less, more preferably 60 J / g or less, still more preferably 55 J / g or less.

[0072] Regarding the heat of fusion, a differential scanning calorimetry (DSC) apparatus can be used. The sample is heated from 30°C to 220°C at a rate of 10°C / minute, and it is calculated based on the magnitude of the melting peak (ΔH) of the obtained endothermic curve.

[0073] Regarding segment B, in terms of improving the oxidation resistance and electrolyte resistance of the electrode material layer, it is preferably composed of fluorine-containing monomer units. The fluorine-containing monomer that can form segment B is not particularly limited as long as it is a monomer containing a fluorine atom, and examples thereof include vinylidene fluoride [VdF], trifluoroethylene, tetrafluoroethylene [TFE], hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, vinyl fluoride, and the like.

[0074] The content of the fluorine-containing monomer units in segment B is preferably 50 mol% or more, more preferably 90 mol% or more, still more preferably 99 mol% or more, and preferably 100 mol% or less, based on all the monomer units constituting segment B.

[0075] Segment B may further contain non-fluorine-containing monomer units. Examples of the non-fluorine-containing monomer include ethylene, propylene, alkyl vinyl ether, and the like. The content of the non-fluorine-containing monomer units is preferably 0 to 50 mol%, more preferably 0 to 10 mol%, still more preferably 0 to 1 mol%, and may be 0 mol%, based on all the monomer units constituting segment B.

[0076] Segment B may further contain units based on monomers having a polar group, and the polar group may be a carbonyl-containing group, epoxy group, hydroxyl group, sulfonic acid group, sulfuric acid group, phosphoric acid group, amino group, amide group, alkoxy group, or the like.

[0077] Examples of the monomer having a polar group include (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, vinylacetic acid (3-butenoic acid), 3-pentenoic acid, 4-pentenoic acid, 3-hexenoic acid, and 4-heptenoic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, methylmaleic acid, and methylmaleic anhydride; alkylidene malonates such as dimethyl methylenemalonate; vinyl carboxyalkyl ethers such as vinyl carboxymethyl ether and vinyl carboxyethyl ether; (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl acrylate and 2-carboxyethyl methacrylate; dicarboxylic acid (meth)acryloyloxyalkyl esters such as acryloyloxyethyl succinate, methacryloyloxyethyl succinate, acryloyloxyethyl phthalate, acryloyloxypropyl succinate, and methacryloyloxyethyl phthalate; and monoesters of unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monomethyl methylmaleate, and monoethyl methylmaleate.

[0078] Segment B preferably contains at least VdF units as fluorine-containing monomer units. By including VdF units in segment B, the melting point of segment B can be easily adjusted within a desired range, the toughness of the electrode material layer can be further improved, and an electrode material layer with excellent electrolyte resistance can be formed. Also, by including VdF units in segment B, the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide can be improved.

[0079] Segment B may contain not only VdF units but also other monomer units other than VdF units. The other monomer can be either a fluorine-containing monomer or a non-fluorine-containing monomer, preferably a fluorine-containing monomer (excluding trifluoroethylene) or a non-fluorine-containing monomer.

[0080] Examples of the fluorine-containing monomer that can form segment B together with VdF include: TFE, hexafluoropropene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), trichlorofluoroethylene, hexafluoroisobutene, vinyl fluoride, etc.

[0081] Examples of the non-fluorine-containing monomer that can form segment B together with VdF include: ethylene, propylene, etc.

[0082] Segment B may contain not only VdF units but also further units based on a monomer having a polar group, and the polar group can be a carbonyl-containing group, epoxy group, hydroxyl group, sulfonic acid group, sulfuric acid group, phosphoric acid group, amino group, amide group, alkoxy group, etc. Monomers having a polar group are as exemplified.

[0083] As other monomers that can form segment B together with VdF, preferably at least one selected from the group consisting of TFE, hexafluoropropene, 2,3,3,3-tetrafluoropropene, and (meth)acrylic acid.

[0084] Regarding the content of VdF units in segment B, in terms of further improving the toughness and electrolyte resistance of the electrode material layer and further improving the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide, relative to all monomer units constituting segment B, it is preferably 97 mol% or more, more preferably more than 99 mol%, still more preferably 99.5 mol% or more, and can be 100 mol% or less.

[0085] Regarding the content of monomer units other than VdF units in segment B, in terms of further improving the toughness and electrolyte resistance of the electrode material layer and further enhancing the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide, it is preferably 3 mol% or less, more preferably less than 1 mol%, still more preferably 0.5 mol% or less, and may be 0 mol% or more, relative to all the monomer units constituting segment B.

[0086] In one embodiment, segment B can be formed by a VdF homopolymer containing only VdF units, or a copolymer containing VdF units and at least one other monomer unit selected from the group consisting of TFE units, hexafluoropropylene units, 2,3,3,3-tetrafluoropropylene units, and (meth)acrylic acid units.

[0087] In the copolymer containing VdF units and other monomer units, the composition (mol%) of VdF units / other monomer units is preferably (97.0 to 99.9) / (3.0 to 0.1).

[0088] As long as the polymer contained in the first non-aqueous electrolyte battery binder contains segment A and segment B, it may also contain other segment C that is different from segment A and segment B.

[0089] As the polymer contained in the first non-aqueous electrolyte battery binder, a block copolymer containing a chain structure represented by any of the following general formulas can be exemplified. General formula: A-B, General formula: A-B-A, General formula: B-A-B, General formula: A-B-C, General formula: B-A-C (In the formula, A represents segment A, B represents segment B, and C represents segment C).

[0090] As the polymer contained in the first non-aqueous electrolyte battery binder, in terms of being able to form an electrode material layer with more excellent flexibility and toughness and being easy to manufacture, it is preferably to contain a chain structure represented by general formula (1) or general formula (2). General formula (1): A-B-A, General formula (2): B-A-B (In the formula, A represents segment A, and B represents segment B).

[0091] As the polymer contained in the binder for the first non-aqueous electrolyte battery, from the viewpoint of the balance between excellent flexibility and excellent toughness, the mass ratio (A / B) of segment A to segment B is preferably from 40 / 60 to 95 / 5, more preferably 50 / 50 or more, still more preferably 60 / 40 or more, and still more preferably 90 / 10 or less.

[0092] The number average molecular weight (in terms of polystyrene) of the polymer contained in the binder for the first non-aqueous electrolyte battery is preferably from 20,000 to 1,500,000, more preferably 40,000 or more, still more preferably 70,000 or more, particularly preferably 140,000 or more, and still more preferably 1,400,000 or less, still more preferably 1,200,000 or less, and particularly preferably 1,100,000 or less. The above number average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0093] The weight average molecular weight (in terms of polystyrene) of the polymer contained in the binder for the first non-aqueous electrolyte battery is preferably from 50,000 to 3,000,000, more preferably 80,000 or more, still more preferably 100,000 or more, still more preferably 200,000 or more, particularly preferably 500,000 or more, and still more preferably 2,400,000 or less, still more preferably 2,200,000 or less, and particularly preferably 2,000,000 or less. The above weight average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0094] The polymer contained in the binder for the first non-aqueous electrolyte battery can be produced, for example, by the following production methods: (1) A method in which a monomer capable of forming segment B is polymerized in the presence of a bromine compound or an iodine compound as a chain transfer agent to prepare a polymer forming segment B, and a monomer capable of forming segment A is polymerized in the presence of the polymer forming segment B to prepare a polymer forming segment A; and (2) A method in which a monomer capable of forming segment A is polymerized in the presence of a bromine compound or an iodine compound as a chain transfer agent to prepare a polymer forming segment A, and a monomer capable of forming segment B is polymerized in the presence of the polymer forming segment A to prepare a polymer forming segment B.

[0095] In the case of using method (1), a polymer having segment A bonded to both ends of the polymer chain forming segment B, that is, a polymer containing a chain structure represented by the general formula (1): A-B-A, can be obtained.

[0096] Further, in the case of the method of use (2), a polymer having chain segments B respectively bonded to both ends of the polymer chain forming the chain segment A can be obtained, that is, a polymer having a chain structure represented by the general formula (2): B-A-B.

[0097] In the methods (1) and (2), a bromine compound or an iodine compound is used as a chain transfer agent. By using a bromine compound or an iodine compound, an iodine atom or a bromine atom is introduced into the end of the polymer chain forming one chain segment, thereby functioning as a bonding site for other chain segments.

[0098] As a polymerization method using a bromine compound or an iodine compound, for example, a method of performing pressurization in the presence of a bromine compound or an iodine compound in a substantially oxygen-free state and simultaneously performing emulsion polymerization in an aqueous medium (iodine transfer polymerization method) can be exemplified. Representative examples of the bromine compound or iodine compound used are, for example, compounds represented by the following general formula: R 8I xBr y (wherein x and y are integers from 0 to 2, and satisfy 1 ≦ x + y ≦ 2, and R 8 is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, and may contain an oxygen atom).

[0099] Examples of the iodine compound include: 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF 2Br 2, BrCF 2CF 2Br, CF 3CFBrCF 2Br, CFClBr 2, BrCF 2CFClBr, CFBrClCFClBr, BrCF 2CF 2CF 2Br, BrCF 2CFBrOCF 3, 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo substitution products of benzene, diiodomonobromo substitution products, and (2-iodoethyl) and (2-bromoethyl) substitution products, etc. These compounds can be used alone or in combination with each other.

[0100] Among them, in terms of polymerization reactivity, crosslinking reactivity, ease of acquisition, etc., it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane.

[0101] In the above manufacturing method, the polymerization of the monomer is preferably carried out using the emulsion polymerization method. In one embodiment, the polymerization of the monomer is carried out in the presence of a polymerization initiator, a surfactant, and a solvent.

[0102] Examples of the polymerization initiator include: oil-soluble radical polymerization initiators or water-soluble radical initiators.

[0103] Examples of the oil-soluble radical polymerization initiator include well-known oil-soluble peroxides. For example, the following representative peroxides can be cited: dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate and di-sec-butyl peroxydicarbonate, peroxy esters such as tert-butyl peroxyisobutyrate and tert-butyl peroxypivalate, dialkyl peroxides such as di-tert-butyl peroxide, etc., and bis(ω-hydro-dodecafluorooctanoyl) peroxide, bis(ω-hydro-tetradecafluorononanoyl) peroxide, bis(ω-hydro-hexadecafluorodecanoyl) peroxide, bis(perfluorobutanoyl) peroxide, bis(perfluoropentanoyl) peroxide, bis(perfluorohexanoyl) peroxide, bis(perfluoroheptanoyl) peroxide, bis(perfluorooctanoyl) peroxide, bis(perfluorononanoyl) peroxide, bis(ω-chloro-hexafluorobutanoyl) peroxide, bis(ω-chloro-decafluorooctanoyl) peroxide, bis(ω-chloro-tetradecafluorononanoyl) peroxide, ω-hydro-dodecafluorooctanoyl-ω-hydro-hexadecafluorodecanoyl-peroxide, ω-chloro-hexafluorobutanoyl-ω-chloro-decafluorooctanoyl-peroxide, ω-hydro-dodecafluorooctanoyl-perfluorobutanoyl-peroxide, bis(dichloropentafluorobutanoyl) peroxide, bis(trichlorooctafluorobutanoyl) peroxide, bis(tetrachloroundecafluorooctanoyl) peroxide, bis(pentachlorotetradecafluorodecanoyl) peroxide, bis(undecachlorotetrafluorodocosanyl) peroxide, etc., bis[perfluoro(or fluorochloro)alkanoyl] peroxides.

[0104] Examples of the water-soluble radical polymerization initiator include well-known water-soluble peroxides. For example, ammonium salts, potassium salts, sodium salts of persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, percarbonic acid, etc., tert-butyl permaleate, tert-butyl hydroperoxide, etc. A reducing agent such as sulfite may also be included, and its usage amount may be 0.1 to 20 times that of the peroxide.

[0105] The addition amount of the polymerization initiator is not particularly limited, and it is sufficient to add, at one time, successively, or continuously in the initial stage of polymerization, an amount such that the polymerization rate does not significantly decrease (for example, several ppm to the water concentration) or more. The upper limit is within the range where the heat of polymerization reaction can be dissipated from the device surface.

[0106] As the surfactant, nonionic surfactants, anionic surfactants, cationic surfactants, etc. can be used. The addition amount (relative to the solvent) is preferably 10 mass ppm to 20 mass%, more preferably 10 mass ppm to 10 mass%, still more preferably 10 to 5000 mass ppm, and particularly preferably 50 to 5000 mass ppm.

[0107] Also, a polymerizable emulsifier can be used as the surfactant. Regarding the polymerizable emulsifier, as long as it is a compound having at least one unsaturated bond and at least one hydrophilic group, it is not particularly limited. For example, CH2 = CFCF2OCF(CF3)CF2OCF(CF3)COONH4, CH2 = CFCF2CF(CF3)OCF2CF2COONH4, CF2 = CFOCF2CF(CF3)OCF(CF3)COONH4 can be cited. The addition amount (relative to the solvent) is preferably 10 to 5000 mass ppm, more preferably 50 to 5000 mass ppm.

[0108] As the solvent, a solvent having no chain transfer property is preferred. Examples of the solvent include water, a mixture of water and a water-soluble organic solvent, or a mixture of water and a water-insoluble organic solvent.

[0109] In the polymerization of the monomer, the polymerization temperature, polymerization pressure, and polymerization time vary depending on the type of the solvent or polymerization initiator, and can be -15 to 150 °C, atmospheric pressure to 6.5 MPa, and 1 to 24 hours. When an oil-soluble radical polymerization initiator is used as the polymerization initiator, the polymerization temperature is preferably 30 to 95 °C. When a water-soluble radical polymerization initiator is used as the polymerization initiator, the polymerization temperature is preferably 0 to 100 °C, more preferably 10 to 95 °C.

[0110] When the monomer is polymerized by the emulsion polymerization method, an aqueous dispersion containing the polymer can be obtained. In the above manufacturing method, by aggregating the polymer in the aqueous dispersion and performing water washing, dehydration, and drying, a powder of the polymer can be obtained. Aggregation can be carried out by adding an inorganic salt or inorganic acid such as aluminum sulfate to the dispersion; or imparting mechanical shear force to the dispersion; or freezing the dispersion.

[0111] Further, the polymer contained in the binder for the first non-aqueous electrolyte battery can be produced by using at least 2,3,3,3-tetrafluoropropene as a monomer according to the methods described in Japanese Patent Application Laid-Open No. 53-3495 and Japanese Patent Publication No. 61-49327.

[0112] 2. Binder for the second non-aqueous electrolyte battery The binder for the second non-aqueous electrolyte battery of the present invention contains a polymer having a glass transition temperature and a melting point, containing 2,3,3,3-tetrafluoropropene units, and having a tetrahydrofuran extraction amount at 25 °C of 5% by mass or less.

[0113] The glass transition temperature of the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 25 °C or lower, more preferably 0 °C or lower, still more preferably -5 °C or lower, and still more preferably -10 °C or lower. The lower limit is not limited and can be -40 °C or higher. Since the binder for the second non-aqueous electrolyte battery contains a polymer having a glass transition temperature, it can form an electrode material layer with excellent flexibility.

[0114] The glass transition temperature can be determined by the following method: Using a differential scanning calorimeter (DSC822e manufactured by Mettler-Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science), after cooling 10 mg of the sample to -75 °C, heating it at a rate of 20 °C / minute to obtain a DSC curve, and taking the temperature of the intersection of the extension line of the baseline before and after the second transition of the DSC curve and the tangent line at the inflection point of the DSC curve as the glass transition temperature.

[0115] The melting point of the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 50 °C or higher, more preferably 90 °C or higher, still more preferably 140 °C or higher, and preferably 240 °C or lower, more preferably 220 °C or lower, and still more preferably 200 °C or lower. Since the binder for the second non-aqueous electrolyte battery contains a polymer having not only a glass transition temperature but also a melting point, it can form an electrode material layer with excellent flexibility and toughness.

[0116] Regarding the melting point, a differential scanning calorimetry (DSC) device can be used to heat the sample from 30 °C to 220 °C at a rate of 10 °C / minute, and the temperature at the peak of the obtained endothermic curve is taken as the melting point.

[0117] The tetrahydrofuran extraction amount of the polymer contained in the binder for the second non-aqueous electrolyte battery is 5% by mass or less, preferably 4% by mass or less, and more preferably 3% by mass or less. Since the binder for the second non-aqueous electrolyte battery contains a polymer with a tetrahydrofuran extraction amount within the above numerical range, an electrode material layer excellent in flexibility and toughness can be formed. The lower limit of the tetrahydrofuran extraction amount is not particularly limited and may be 1% by mass or more or 2% by mass or more.

[0118] Regarding the tetrahydrofuran extraction amount, it can be measured by immersing the polymer in tetrahydrofuran at 25°C for 24 hours and partially drying the filtered solution.

[0119] The polymer contained in the binder for the second non-aqueous electrolyte battery contains 2,3,3,3-tetrafluoropropene units. Since the binder for the second non-aqueous electrolyte battery contains 2,3,3,3-tetrafluoropropene units, it can impart solvent solubility of the binder to solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide, can form an electrode material layer excellent in flexibility and toughness, and further can obtain an electrode paste excellent in viscosity stability and can form an electrode material layer excellent in electrolyte resistance.

[0120] The polymer contained in the binder for the second non-aqueous electrolyte battery preferably contains fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units). By introducing fluorine-containing monomer units into the polymer, the glass transition temperature and melting point of the polymer can be easily adjusted, an electrode material layer more excellent in flexibility and toughness can be formed, and further an electrode paste more excellent in viscosity stability can be obtained and an electrode material layer more excellent in electrolyte resistance can be formed.

[0121] The fluorine-containing monomer that can constitute the polymer contained in the binder for the second non-aqueous electrolyte battery is not particularly limited as long as it is a monomer other than 2,3,3,3-tetrafluoropropene and contains a fluorine atom, and examples thereof include vinylidene fluoride [VdF], trifluoroethylene, tetrafluoroethylene [TFE], hexafluoropropene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, vinyl fluoride, etc.

[0122] As a fluorine-containing monomer that can constitute a polymer contained in the binder for the second non-aqueous electrolyte battery, it is preferably at least one selected from the group consisting of VdF, TFE, hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), and trichloroethylene, more preferably at least one selected from the group consisting of VdF and TFE, and still more preferably VdF.

[0123] When the polymer contained in the binder for the second non-aqueous electrolyte battery contains VdF units as fluorine-containing monomer units, the solvent solubility of the binder in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide is further improved. And by using the binder for the second non-aqueous electrolyte battery, an electrode material layer with more excellent flexibility and toughness can be formed, and furthermore, an electrode paste with more excellent viscosity stability can be obtained, and an electrode material layer with more excellent electrolyte resistance can be formed.

[0124] The content of 2,3,3,3-tetrafluoropropylene units in the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 1 to 65 mol%, more preferably 5 mol% or more, still more preferably 9 mol% or more, still more preferably 12 mol% or more, particularly preferably 14 mol% or more, and more preferably 62 mol% or less, still more preferably 40 mol% or less, still more preferably 32 mol% or less, particularly preferably 24 mol% or less, relative to all monomer units constituting the polymer.

[0125] The content of fluorine-containing monomer units in the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 99 to 35 mol%, more preferably 95 mol% or less, still more preferably 91 mol% or less, still more preferably 88 mol% or less, particularly preferably 86 mol% or less, and more preferably 38 mol% or more, still more preferably 60 mol% or more, still more preferably 68 mol% or more, particularly preferably 76 mol% or more, relative to all monomer units constituting the polymer.

[0126] The content of VdF units in the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 99 to 35 mol%, more preferably 95 mol% or less, still more preferably 91 mol% or less, still more preferably 88 mol% or less, particularly preferably 86 mol% or less, and more preferably 38 mol% or more, still more preferably 60 mol% or more, still more preferably 68 mol% or more, particularly preferably 76 mol% or more, relative to all monomer units constituting the polymer.

[0127] The polymer contained in the binder for the second non-aqueous electrolyte battery may further contain monomer units that do not contain fluorine. Examples of the monomers that do not contain fluorine include ethylene, propylene, alkyl vinyl ether, etc. The content of the monomer units that do not contain fluorine is preferably 0 to 40 mol%, more preferably 0 to 8 mol%, still more preferably 0 to 1 mol%, and may also be 0 mol%, based on all the monomer units constituting the polymer.

[0128] The polymer contained in the binder for the second non-aqueous electrolyte battery may further contain units based on monomers having reactive groups. The above reactive groups may be a cyano group, a carboxyl group, an alkoxycarbonyl group, I, Br, -CH2OH, a carbon-carbon double bond, etc. The content of the units based on monomers having reactive groups is preferably 0 to 10 mol%, more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, and may also be 0 mol%, based on all the monomer units constituting the polymer.

[0129] The polymer contained in the binder for the second non-aqueous electrolyte battery may further contain units based on monomers having polar groups. The above polar groups may be a carbonyl group-containing group, an epoxy group, a hydroxyl group, a sulfonic acid group, a sulfuric acid group, a phosphoric acid group, an amino group, an amide group, an alkoxy group, etc.

[0130] Examples of the monomers having polar groups include (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, vinylacetic acid (3-butenoic acid), 3-pentenoic acid, 4-pentenoic acid, 3-hexenoic acid, 4-heptenoic acid, etc.; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, methylmaleic acid, methylmaleic anhydride, etc.; alkylidene malonates such as dimethyl methylenemalonate; vinyl carboxyalkyl ethers such as vinyl carboxymethyl ether and vinyl carboxyethyl ether; (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl acrylate and 2-carboxyethyl methacrylate; dicarboxylic acid (meth)acryloyloxyalkyl esters such as acryloyloxyethyl succinate, methacryloyloxyethyl succinate, acryloyloxyethyl phthalate, acryloyloxypropyl succinate, methacryloyloxyethyl phthalate, etc.; monoesters of unsaturated dicarboxylic acids such as monomethyl maleate, monoethyl maleate, monomethyl methylmaleate, monoethyl methylmaleate, etc.

[0131] The content of the units based on monomers having polar groups is preferably 0 to 10 mol%, more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, and may also be 0 mol%, based on all the monomer units constituting the polymer.

[0132] In one embodiment, the polymer contained in the binder for the second non-aqueous electrolyte battery contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (wherein, excluding 2,3,3,3-tetrafluoropropene units), and the content of monomer units other than 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units is preferably 0 to 10 mol%, more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, still more preferably 0 to 0.1 mol%, and particularly preferably 0 mol% with respect to all monomer units constituting the polymer. The content of 2,3,3,3-tetrafluoropropene units and the content of fluorine-containing monomer units can be within the above ranges.

[0133] In one embodiment, the polymer contained in the binder for the second non-aqueous electrolyte battery contains 2,3,3,3-tetrafluoropropene units and VdF units, and the content of monomer units other than 2,3,3,3-tetrafluoropropene units and VdF units is preferably 0 to 10 mol%, more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, still more preferably 0 to 0.1 mol%, and particularly preferably 0 mol% with respect to all monomer units constituting the polymer. The content of 2,3,3,3-tetrafluoropropene units and the content of VdF units can be within the above ranges.

[0134] The number average molecular weight (in terms of polystyrene) of the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 20,000 to 1,500,000, more preferably 40,000 or more, still more preferably 70,000 or more, particularly preferably 140,000 or more, and more preferably 1,400,000 or less, still more preferably 1,200,000 or less, and particularly preferably 1,100,000 or less. The above number average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0135] The weight average molecular weight (in terms of polystyrene) of the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 50,000 to 3,000,000, more preferably 80,000 or more, still more preferably 100,000 or more, still more preferably 200,000 or more, particularly preferably 500,000 or more, and more preferably 2,400,000 or less, still more preferably 2,200,000 or less, and particularly preferably 2,000,000 or less. The above weight average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0136] The heat of fusion of the polymer contained in the binder for the second non-aqueous electrolyte battery is preferably 1 J / g or more, more preferably 3 J / g or more, still more preferably 5 J / g or more, even more preferably 8 J / g or more, and preferably 40 J / g or less, more preferably 30 J / g or less, still more preferably 20 J / g or less.

[0137] In one embodiment, the polymer contained in the binder for the second non-aqueous electrolyte battery includes two or more segments. By configuring the polymer with two or more segments, it is possible to easily impart a glass transition temperature and a melting point to the polymer, and it is possible to easily adjust the glass transition temperature and the melting point of the polymer, and the flexibility and toughness of the electrode material layer can be further improved.

[0138] When the polymer contained in the binder for the second non-aqueous electrolyte battery includes two or more segments, the configuration of each segment can be the same as the configuration of each segment of the polymer contained in the binder for the first non-aqueous electrolyte battery. That is, the polymer contained in the binder for the second non-aqueous electrolyte battery can include segment A and segment B, similar to the polymer contained in the binder for the first non-aqueous electrolyte battery, and can adopt the same configuration as the polymer contained in the binder for the first non-aqueous electrolyte battery.

[0139] Regarding the polymer contained in the binder for the second non-aqueous electrolyte battery, for example, it can be manufactured by the above method which is the manufacturing method of the polymer contained in the binder for the first non-aqueous electrolyte battery.

[0140] The binder for the first non-aqueous electrolyte battery and the binder for the second non-aqueous electrolyte battery (hereinafter, in the case of being simply referred to as "binder for non-aqueous electrolyte battery") may contain other polymers in addition to the above polymer. Examples of other polymers include: fluoropolymers, polymethacrylates, polymethyl methacrylates, polyacrylonitriles, polyimides, polyamides, polyamideimides, polycarbonates, styrene rubbers, butadiene rubbers, styrene-butadiene rubbers, polyacrylic acids, etc.

[0141] The binder for non-aqueous electrolyte battery of the present invention can be suitably used as a material for forming batteries such as secondary batteries and capacitors.

[0142] The present invention also relates to the use of a binder for forming a non-aqueous electrolyte battery, the binder containing a polymer which includes a segment A having a glass transition temperature of 25°C or lower and a segment B having a melting point of 50°C or higher. The binder can be particularly suitably used for forming an electrode material layer of a non-aqueous electrolyte battery.

[0143] Furthermore, the present invention also relates to the use of a binder for forming a non-aqueous electrolyte battery, the binder containing a polymer which has a glass transition temperature and a melting point, contains 2,3,3,3-tetrafluoropropene units, and has a tetrahydrofuran extraction amount at 25°C of 5 mass% or less. The binder can be particularly suitably used for forming an electrode material layer of a non-aqueous electrolyte battery.

[0144] The battery can be a primary battery, a storage battery (secondary battery) or a storage element. The non-aqueous electrolyte battery includes all non-aqueous electrolyte batteries equipped with an electrolyte and a power generation element. Examples of non-aqueous electrolyte batteries include: lithium ion primary batteries, lithium ion secondary batteries, sodium ion secondary batteries, nickel metal hydride batteries, lithium ion capacitors, electric double layer capacitors, etc.

[0145] Regarding the binder for a non-aqueous electrolyte battery of the present invention, since it can form an electrode material layer excellent in flexibility and toughness, it is suitably used as a binder for electrodes of batteries such as secondary batteries and capacitors. Also, the binder for a non-aqueous electrolyte battery of the present invention can also be used as a binder for a separator coating of a secondary battery.

[0146] The binder for a non-aqueous electrolyte battery of the present invention can be a binder for a non-aqueous electrolyte secondary battery. In the present invention, the binder for a non-aqueous electrolyte secondary battery includes binders for the positive electrode, negative electrode, and separator of a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery is preferably a lithium ion secondary battery.

[0147] 3. Electrode binder The electrode binder for a non-aqueous electrolyte battery of the present invention contains the above-mentioned binder for a non-aqueous electrolyte battery, a powdered electrode material, and water or a non-aqueous solvent. The electrode binder of the present invention can be an electrode binder for a non-aqueous electrolyte secondary battery or an electrode binder for a lithium ion secondary battery. Since the electrode binder of the present invention contains the above-mentioned binder for a non-aqueous electrolyte battery, it can form an electrode material layer excellent in flexibility and toughness.

[0148] The electrode mixture can be a positive electrode mixture for manufacturing a positive electrode, or a negative electrode mixture for manufacturing a negative electrode. The electrode material layer formed from the electrode mixture of the present invention only needs to contain the above-mentioned binder for battery and powder electrode material, and can be a positive electrode material layer or a negative electrode material layer.

[0149] The powder electrode material is a powder electrode material for a battery, preferably including an electrode active material. The electrode active material is divided into a positive electrode active material and a negative electrode active material. In the case of a lithium ion secondary battery, as the positive electrode active material, as long as it can electrochemically occlude and release lithium ions, there is no particular limitation, but preferably a lithium composite oxide, more preferably a lithium transition metal composite oxide. As the above-mentioned positive electrode active material, it is also preferably a transition metal phosphate compound containing lithium. The above-mentioned positive electrode active material is also preferably a substance containing lithium and at least one transition metal such as a lithium transition metal composite oxide and a transition metal phosphate compound containing lithium.

[0150] As the transition metal of the lithium transition metal composite oxide, preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. As specific examples of the lithium transition metal composite oxide, examples include: lithium-cobalt composite oxides such as LiCoO2, lithium-nickel composite oxides such as LiNiO2, lithium-manganese composite oxides such as LiMnO2, LiMn2O4, Li2MnO3, etc., and those obtained by substituting a part of the transition metal atoms that are the main body of these lithium transition metal composite oxides with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, etc. As the above-mentioned substituted products, examples include: lithium-nickel-manganese composite oxides, lithium-nickel-cobalt-aluminum composite oxides, lithium-nickel-cobalt-manganese composite oxides, lithium-manganese-aluminum composite oxides, lithium-titanium composite oxides, etc. More specifically, examples include: LiNi0.5Mn0.5O2, LiNi0.85Co0.10Al0.05O2, LiNi0.33Co0.33Mn0.33O2, LiNi0.5Mn0.3Co0.2O2, LiNi0.6Mn0.2Co0.2O2, LiNi0.8Mn0.1Co0.1O2, LiNi0.9Mn0.05Co0.05O2, LiMn1.8Al0.2O4, LiMn1.5Ni0.5O4, Li4Ti5O12, LiNi0.82Co0.15Al0.03O2, etc.

[0151] As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable. Specific examples of the lithium-containing transition metal phosphate compound include, for example, iron phosphates such as LiFePO4, Li3Fe2(PO4)3, LiFeP2O7, cobalt phosphates such as LiCoPO4, and those in which a part of the transition metal atoms that are the main body of these lithium transition metal phosphate compounds are replaced with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc.

[0152] In particular, from the viewpoints of high voltage, high energy density, charge-discharge cycle characteristics, etc., LiCoO2, LiNiO2, LiMn2O4, LiNi0.82Co0.15Al0.03O2, LiNi0.33Mn0.33Co0.33O2, LiNi0.5Mn0.3Co0.2O2, LiNi0.6Mn0.2Co0.2O2, LiNi0.8Mn0.1Co0.1O2, LiNi0.9Mn0.05Co0.05O2, LiFePO4 are preferable.

[0153] Further, as the lithium transition metal composite oxide, a lithium-nickel-based composite oxide is preferable, and more preferably, it is represented by the general formula (7): General formula (7): LiyNi1 - xMxO2 (In the formula, x is a coefficient satisfying 0.01 ≦ x ≦ 0.5, y is a coefficient satisfying 0.9 ≦ y ≦ 1.2, and M represents a metal atom (excluding Li and Ni)) The lithium-nickel-based composite oxide represented by the above formula. Thus, the lithium transition metal composite oxide with a high nickel content contributes to increasing the capacitance of the secondary battery.

[0154] In the general formula (7), x is a coefficient satisfying 0.01 ≦ x ≦ 0.5. From the viewpoint of obtaining a secondary battery with a higher capacitance, it is preferably 0.05 ≦ x ≦ 0.4, and more preferably 0.10 ≦ x ≦ 0.3.

[0155] In the general formula (7), examples of the metal atom M include V, Ti, Cr, Mn, Fe, Co, Cu, Al, Zn, Mg, Ga, Zr, Si, etc. As the metal atom M, preferred are transition metals such as V, Ti, Cr, Mn, Fe, Co, Cu, etc., or combinations of the above transition metals with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mg, Ga, Zr, Si, etc.

[0156] As the lithium transition metal composite oxide with a relatively high nickel content, preferably at least one selected from the group consisting of LiNi 0.80Co 0.15Al 0.05O 2, LiNi 0.82Co 0.15Al 0.03O 2, LiNi 0.33Mn 0.33Co 0.33O 2, LiNi 0.5Mn 0.3Co 0.2O 2, LiNi 0.6Mn 0.2Co 0.2O 2, LiNi 0.8Mn 0.1Co 0.1O 2 and LiNi 0.90Mn 0.05Co 0.05O 2, more preferably at least one selected from the group consisting of LiNi 0.82Co 0.15Al 0.03O 2, LiNi 0.6Mn 0.2Co 0.2O 2, LiNi 0.8Mn 0.1Co 0.1O 2 and LiNi 0.9Mn 0.05Co 0.05O 2.

[0157] Also, those in which a substance having a composition different from that of the substance constituting the main cathode active material is attached to the surface of the cathode active material can also be used. Examples of the surface-attached substance include oxides such as alumina, silica, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, sulfates such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, magnesium carbonate, etc.

[0158] These surface-attached substances can be attached to the surface of the cathode active material, for example, by methods such as dissolving or suspending in a solvent and impregnating and adding to the cathode active material followed by drying; dissolving or suspending the surface-attached substance precursor in a solvent and impregnating and adding to the cathode active material, and then reacting it by heating, etc.; adding to the cathode active material precursor and firing simultaneously, etc.

[0159] As the amount of the surface-attached substance, relative to the positive electrode active material, by mass, the lower limit is preferably 0.1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more, and the upper limit is preferably 20% or less, more preferably 10% or less, still more preferably 5% or less. By the surface-attached substance, the oxidation reaction of the non-aqueous electrolyte on the surface of the positive electrode active material can be suppressed, and the battery life can be extended. However, when the attached amount is too small, the effect cannot be fully exhibited. When the attached amount is too large, since the entry and exit of lithium ions are hindered, there is a case where the resistance increases.

[0160] Regarding the particle shape of the positive electrode active material, the previously used block shape, polyhedron shape, spherical shape, ellipsoidal shape, plate shape, needle shape, column shape, etc. are used. Among them, those formed by aggregating primary particles to form secondary particles are preferred, and the shape of the secondary particles is spherical or ellipsoidal. Generally, with the charge and discharge of the electrochemical device, the active material in the electrode expands and contracts, and thus it is easy to damage the active material or cause deterioration such as cutting off the conductive path due to this stress. Therefore, compared with a single-particle active material having only primary particles, those formed by aggregating primary particles to form secondary particles are preferred because they can relieve the stress of expansion and contraction and prevent deterioration. Also, compared with particles having an equiaxed orientation such as a plate shape, spherical or ellipsoidal particles have less orientation during electrode forming, so the expansion and contraction of the electrode during charge and discharge are also less, and even when mixed with a conductive agent during electrode production, they are easy to mix uniformly, so they are preferred.

[0161] The tap density of the positive electrode active material is usually 1.3 g / cm 3 or more, preferably 1.5 g / cm 3 or more, still more preferably 1.6 g / cm 3 or more, and most preferably 1.7 g / cm 3 or more. If the tap density of the positive electrode active material is lower than the above lower limit, when forming the positive electrode material layer, the required amount of the dispersion medium increases, and the required amounts of the conductive agent or the binder increase, and the filling rate of the positive electrode active material into the positive electrode material layer is limited, resulting in a case where the battery capacity is limited. By using a metal composite oxide powder with a high tap density, a high-density positive electrode material layer can be formed. Generally, the larger the tap density, the better, and there is no particular upper limit. However, if it is too large, the diffusion rate of lithium ions using the non-aqueous electrolyte as a medium in the positive electrode material layer is limited, and it is easy to reduce the load characteristics. Therefore, it is usually 3.5 g / cm 3 or less, preferably 3.3 g / cm 3 or less.

[0162] Regarding the tapped density of the positive electrode active material, the sample is passed through a sieve with a mesh size of 300 μm and dropped into a 20 cm3 tapping cell. After filling the cell volume, using a powder density meter (for example, Tap Denser manufactured by SEISHIN Enterprise Co., Ltd.), tapping is performed with a stroke length of 10 mm for 1000 times, and the density calculated based on the volume and weight of the sample at this time is defined as the tapped density.

[0163] The median diameter d50 of the particles of the positive electrode active material (the secondary particle diameter in the case where primary particles aggregate to form secondary particles) is usually 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more, most preferably 3 μm or more, and usually 20 μm or less, preferably 18 μm or less, more preferably 16 μm or less, most preferably 15 μm or less. If it is lower than the above lower limit, there may be a case where a high bulk density product cannot be obtained. If it exceeds the upper limit, the diffusion of lithium in the particles takes time, so problems such as the following may occur: the battery performance is reduced, or stripes may occur when the active material, conductive agent, binder, etc. are made into a slurry with a solvent and coated in a film shape when manufacturing the battery positive electrode. Here, by mixing two or more positive electrode active materials having different median diameters d50, the filling property during the production of the positive electrode can be further improved.

[0164] Furthermore, the median diameter d50 in the present invention is measured by a known laser diffraction / scattering particle size distribution measuring device. When using LA-920 manufactured by HORIBA as the particle size distribution meter, a 0.1 mass% aqueous solution of sodium hexametaphosphate is used as the dispersion medium for measurement, and the measurement refractive index is set to 1.24 after ultrasonic dispersion for 5 minutes for measurement.

[0165] When secondary particles are formed by aggregation of primary particles, the average primary particle diameter of the positive electrode active material is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.08 μm or more, most preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less, more preferably 1 μm or less, most preferably 0.6 μm or less. If it exceeds the above upper limit, it is difficult to form spherical secondary particles, which will have an adverse effect on the powder filling property, or greatly reduce the specific surface area, so there is a high possibility that the battery performance such as the output characteristics will decrease. On the contrary, if it is lower than the above lower limit, the crystal growth is usually incomplete, so there are cases where problems such as poor reversibility of charge and discharge occur. Furthermore, the primary particle diameter is measured by observing with a scanning electron microscope (SEM). Specifically, the primary particle diameter is obtained by finding the longest value of the intercept of the left and right boundary lines of the primary particle and the horizontal line in a photograph at a magnification of 10,000 times for any 50 primary particles and taking the average value.

[0166] The BET specific surface area of the positive electrode active material is 0.1 m 2 / g or more, preferably 0.15 m 2 / g or more, more preferably 0.18 m 2 / g or more, and 4.0 m 2 / g or less, preferably 2.5 m 2 / g or less, more preferably 1.5 m 2 / g or less. If the BET specific surface area is less than this range, the battery performance is likely to decrease. If the BET specific surface area is greater than this range, it becomes difficult to increase the tap density, and there are cases where problems are likely to occur in the coatability when forming the positive electrode material layer.

[0167] Regarding the BET specific surface area, using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken), after pre-drying the sample at 150°C for 30 minutes under nitrogen flow, using a nitrogen-helium mixed gas precisely adjusted so that the value of the relative pressure of nitrogen to atmospheric pressure reaches 0.3, the measurement is carried out by the nitrogen adsorption BET single point method based on the gas flow method, and the measured value is defined as the BET specific surface area.

[0168] As a method for manufacturing a positive electrode active material, a general method for manufacturing an inorganic compound is used. In particular, in order to produce a spherical or ellipsoidal active material, various methods are considered. For example, the following methods can be cited: dissolving or pulverizing and dispersing a transition metal raw material substance such as a transition metal nitrate or sulfate, and a raw material substance of other elements as needed, in a solvent such as water, stirring and simultaneously adjusting the pH to produce a spherical precursor and recovering it, and if necessary, drying it and then adding a Li source such as LiOH, Li₂CO₃, or LiNO₃, and firing it at a high temperature to obtain the active material; dissolving or pulverizing and dispersing a transition metal raw material substance such as a transition metal nitrate, sulfate, hydroxide, or oxide, and a raw material substance of other elements as needed, in a solvent such as water, drying and molding it using a spray dryer or the like to produce a spherical or ellipsoidal precursor, adding a Li source such as LiOH, Li₂CO₃, or LiNO₃ thereto, and firing it at a high temperature to obtain the active material; and dissolving or pulverizing and dispersing a transition metal raw material substance such as a transition metal nitrate, sulfate, hydroxide, or oxide, a Li source such as LiOH, Li₂CO₃, or LiNO₃, and a raw material substance of other elements as needed, in a solvent such as water, drying and molding it using a spray dryer or the like to produce a spherical or ellipsoidal precursor, and firing it at a high temperature to obtain the active material.

[0169] Furthermore, in the present invention, one type of the positive electrode active material powder can be used alone, or two or more types having different compositions or different powder physical properties can be used in combination at any combination and ratio.

[0170] As the negative electrode active material, there is no particular limitation as long as it can electrochemically occlude and release lithium ions. Examples include: carbonaceous materials, metal oxides such as tin oxide or silicon oxide, metal composite oxides, lithium alloys such as lithium metal or lithium-aluminum alloy, metals such as Sn or Si that can form an alloy with lithium, etc. One type of these can be used alone, or two or more types can be used in combination at any combination and ratio.

[0171] As the metal composite oxide, there is no particular limitation as long as it can occlude and release lithium, but from the viewpoint of the charge-discharge characteristics at a high current density, it is preferably composed of titanium and / or lithium as a constituent.

[0172] As the carbonaceous material, Those selected from the following materials have a good balance between the initial irreversible capacitance and the charge-discharge characteristics at a high current density, so they are preferred, that is: (1) Natural graphite; (2) Artificial carbonaceous substances and artificial graphiteaceous substances; carbonaceous substances {for example, natural graphite, coal-based coke, petroleum-based coke, coal-based asphalt, petroleum-based asphalt, or those obtained by subjecting such asphalt to oxidation treatment, carbon materials obtained by subjecting needle coke, pitch coke, and their partially graphitized products, pyrolysis products of organic substances such as furnace black, acetylene black, and asphalt-based carbon fibers, carbonizable organic substances (for example, coal tar asphalt from soft asphalt to hard asphalt, or coal-based heavy oil such as dry distillation liquefied oil, straight-run heavy oil such as atmospheric residue and vacuum residue, cracked petroleum heavy oil such as ethylene tar by-produced during thermal cracking of crude oil and naphtha, and furthermore, aromatic hydrocarbons such as acenaphthene, decacyclene, anthracene, and phenanthrene, ph or N-ring compounds such as acridine, S-ring compounds such as thiophene and bithiophene, polyphenyls such as biphenyl and terphenyl, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, insolubilized products thereof, organic polymers such as nitrogen-containing polyacrylonitrile and polypyrrole, organic polymers such as sulfur-containing polythiophene and polystyrene, natural polymers such as polysaccharides represented by cellulose, lignin, mannan, polygalacturonic acid, polyglucosamine, and sucrose, thermoplastic resins such as polyphenylene sulfide and polyphenylene ether, thermosetting resins such as furfuryl alcohol resin, phenol-formaldehyde resin, and imide resin) and their carbides, or solutions obtained by dissolving carbonizable organic substances in low-molecular organic solvents such as benzene, toluene, xylene, quinoline, and n-hexane and their carbides} carbonaceous materials obtained by heat-treating once or more in the range of 400 to 3200 °C; (3) A carbonaceous material in which the negative electrode material layer is composed of at least two or more types of carbonaceous substances having different crystallinities and / or having an interface where carbonaceous substances having different crystallinities are joined; (4) A carbonaceous material in which the negative electrode material layer is composed of at least two or more types of carbonaceous substances having different orientations and / or having an interface where carbonaceous substances having different orientations are joined.

[0173] Regarding the content of the electrode active material (positive electrode active material or negative electrode active material), in order to increase the capacitance of the obtained electrode, it is preferably 40% by mass or more in the electrode binder.

[0174] The above powder electrode material may further contain a conductive agent. Examples of the conductive agent include: carbon blacks such as acetylene black and Ketjenblack, carbon materials such as graphite, carbon fibers, carbon nanotubes, carbon nanohorns, graphene, etc.

[0175] The ratio of the powder electrode material (active material and conductive agent) in the electrode binder to the above battery binder is usually about 80:20 to 99.5:0.5 by mass ratio, and is determined considering the retention of the powder component, the close contact with the current collector, and the conductivity of the electrode.

[0176] In the case of the blending ratio as described above, in the electrode material layer formed on the current collector, the above-mentioned battery binder cannot completely fill the gaps between the powder components. However, if water or a non-aqueous solvent that can dissolve or disperse the battery binder well is used as the solvent, in the dried electrode material layer, the battery binder is uniformly dispersed and forms a mesh-like structure, and can hold the powder components well, so this is preferred.

[0177] The electrode binder of the present invention contains water or a non-aqueous solvent. Examples of the non-aqueous solvent include nitrogen-containing organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and dimethylformamide; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as diethyl ether; and furthermore, common organic solvents with low boiling points such as their mixed solvents.

[0178] Regarding the electrode binder of the present invention, in terms of excellent stability and coatability of the electrode binder, it is preferably to contain a non-aqueous solvent, and preferably to contain at least one selected from the group consisting of N-methyl-2-pyrrolidone and N,N-dimethylacetamide, and more preferably to contain N-methyl-2-pyrrolidone.

[0179] The amount of water or non-aqueous solvent in the above-mentioned electrode binder is determined in consideration of the coatability on the current collector and the film-forming property after drying. Usually, the ratio of the battery binder to water or non-aqueous solvent is preferably 0.5:99.5 to 20:80 by mass ratio.

[0180] Regarding the above-mentioned electrode binder, in order to further improve the adhesion to the current collector, for example, it may further contain: acrylic resins such as polyacrylic acid, polymethacrylate, and polymethyl methacrylate; polyimide, polyamide, and polyamide-imide resins; styrene rubber, butadiene rubber, styrene-butadiene rubber, etc.

[0181] Regarding the above-mentioned electrode binder, in order to improve the dispersion stability of the electrode slurry, dispersants such as resin-based or cationic surfactants and non-ionic surfactants having surfactant effects can also be added.

[0182] As the content of the non-aqueous electrolyte battery binder in the electrode binder, relative to the mass of the electrode binder, it is preferably 0.1 to 20% by mass, more preferably 0.2 to 10% by mass, and still more preferably 0.5 to 3% by mass.

[0183] As a method for preparing an electrode mixture, examples include methods such as dispersing and mixing the above-mentioned powder electrode material in a solution or dispersion obtained by dissolving or dispersing a binder for a non-aqueous electrolyte battery in water or a non-aqueous solvent. Then, the obtained electrode mixture is uniformly coated on a current collector such as a metal foil or a metal mesh and dried, and if necessary, pressed to form a thin electrode material layer on the current collector, thereby producing a thin-film electrode.

[0184] In addition, it is also possible to first mix the powder of the binder for a non-aqueous electrolyte battery with the electrode material powder, and then add water or a non-aqueous solvent to prepare the electrode mixture. Also, it is possible to previously heat-melt the powder of the binder for a non-aqueous electrolyte battery and the electrode material and extrude them using an extruder to produce a thin-film electrode mixture, and then laminate it on a current collector coated with a conductive adhesive or a general organic solvent to produce an electrode sheet. Furthermore, it is also possible to coat a solution or dispersion of the powder of the binder for a non-aqueous electrolyte battery and the electrode material on a pre-preformed electrode material. Thus, the application method of the binder for a non-aqueous electrolyte battery is not particularly limited.

[0185] 4. Electrode The electrode of the present invention contains the above-mentioned binder for a non-aqueous electrolyte battery. The electrode of the present invention is preferably an electrode for a non-aqueous electrolyte battery. Since the electrode of the present invention contains the above-mentioned binder for a non-aqueous electrolyte battery, even if the powder electrode material is thickly coated for high density and wound and pressed, the electrode will not break, and there will be no peeling off of the powder electrode material and no peeling from the current collector.

[0186] The above-mentioned electrode preferably includes a current collector and an electrode material layer formed on the current collector and containing the above-mentioned powder electrode material and the above-mentioned binder for a non-aqueous electrolyte battery. The above-mentioned electrode can be a positive electrode or a negative electrode, and is preferably a positive electrode.

[0187] As the current collector (positive electrode current collector and negative electrode current collector), for example, metal foils or metal meshes such as iron, stainless steel, copper, aluminum, nickel, and titanium can be cited. Among them, as the positive electrode current collector, aluminum foil, etc. are preferred, and as the negative electrode current collector, copper foil, etc. are preferred.

[0188] The electrode of the present invention can be manufactured by the above-mentioned method, for example. Since the coating property of the above-mentioned electrode mixture is excellent, by using the electrode mixture to produce the electrode material layer of the electrode of the present invention, an electrode having a smooth and uniform thickness electrode material layer can be easily produced.

[0189] 5. Non-aqueous electrolyte battery The non-aqueous electrolyte battery of the present invention includes the above-mentioned electrode. The non-aqueous electrolyte battery of the present invention is preferably a non-aqueous electrolyte secondary battery. In one embodiment, the non-aqueous electrolyte battery of the present invention includes a positive electrode formed by holding a positive electrode mixture on a positive electrode current collector, a negative electrode formed by holding a negative electrode mixture on a negative electrode current collector, and an electrolyte solution. In the non-aqueous electrolyte secondary battery of the present invention, as long as at least one of the positive electrode and the negative electrode is the above-mentioned electrode, it is preferably that the positive electrode is the above-mentioned electrode. The secondary battery is preferably a lithium ion secondary battery.

[0190] The non-aqueous electrolyte secondary battery of the present invention preferably further includes a non-aqueous electrolyte solution. The above non-aqueous electrolyte solution is not particularly limited, and known hydrocarbon solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate can be used; one or more of fluorine-based solvents such as fluoroethylene carbonate, fluorinated ethers, and fluorinated carbonates. Any of the previously known electrolytes can also be used as the electrolyte, and LiClO4, LiAsF6, LiPF6, LiBF4, LiCl, LiBr, CH3SO3Li, CF3SO3Li, cesium carbonate, etc. can be used.

[0191] Also, a separator can be interposed between the positive electrode and the negative electrode. As the separator, those previously known can be used, and a separator obtained by applying the above-mentioned battery binder can also be used.

[0192] Preferably, the above-mentioned non-aqueous electrolyte battery binder is used for at least one of the positive electrode, the negative electrode, and the separator of the secondary battery (preferably a lithium ion secondary battery).

[0193] A secondary battery film composed of the above-mentioned non-aqueous electrolyte battery binder is also one of the preferred embodiments of the present invention.

[0194] A secondary battery laminate having a base material and a layer formed on the base material and composed of the above-mentioned non-aqueous electrolyte battery binder is also one of the preferred embodiments of the present invention. Examples of the above-mentioned base material include those exemplified as the above-mentioned current collector, or known base materials (such as porous membranes) used for the separator of the secondary battery.

[0195] Regarding the electrode of the present invention, since it has an electrode material layer with excellent flexibility and toughness, it can be suitably used as an electrode for a wound non-aqueous electrolyte secondary battery. Also, the non-aqueous electrolyte secondary battery of the present invention can be a wound non-aqueous electrolyte secondary battery.

[0196] The above describes the embodiments, but it should be understood that various changes in form or details can be made without departing from the gist and scope of the patent application.

[0197] <1>According to the first aspect of the present invention, A binder for a non-aqueous electrolyte battery is provided, which contains a polymer, and the polymer includes a segment A having a glass transition temperature of 25°C or lower and a segment B having a melting point of 50°C or higher. <2>According to the second aspect of the present invention, The binder for a non-aqueous electrolyte battery according to the first aspect is provided, wherein the segment A has a heat of fusion of less than 5 J / g, and the segment B has a heat of fusion of 5 J / g or more. <3>According to the third aspect of the present invention, The binder for a non-aqueous electrolyte battery according to the first or second aspect is provided, wherein the polymer contains a chain structure represented by the general formula (1) or the general formula (2). General formula (1): A-B-A, General formula (2): B-A-B (In the formula, A represents segment A, and B represents segment B). <4>According to the fourth aspect of the present invention, The binder for a non-aqueous electrolyte battery according to any one of the first to third aspects is provided, wherein the segment A of the polymer contains a fluorine-containing monomer unit. <5>According to the fifth aspect of the present invention, The binder for a non-aqueous electrolyte battery according to any one of the first to fourth aspects is provided, wherein the segment A of the polymer contains a vinylidene fluoride unit. <6>According to the sixth aspect of the present invention, The binder for a non-aqueous electrolyte battery according to any one of the first to fifth aspects is provided, wherein the segment A of the polymer contains a vinylidene fluoride unit and at least one selected from the group consisting of repeating units represented by any of the following formulas. Formula: -CF 2-CF[-CF 3]-, Formula: -CH 2-CFRf 1- (In the formula, Rf 1 is a linear or branched fluorinated alkyl or fluorinated alkoxy group having 1 to 12 carbon atoms, and when the number of carbon atoms is 2 or more, it may contain an oxygen atom between carbon-carbon atoms), Formula: -CHF-CHRf 2- (In the formula, Rf 2 is a linear or branched fluorinated alkyl group or fluorinated alkoxy group having 1 to 12 carbon atoms, and when the number of carbon atoms is 2 or more, it may contain an oxygen atom between carbon-carbon atoms). <7>According to the 7th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 1st to 6th aspects, wherein the segment A of the above polymer contains a vinylidene fluoride unit and a 2,3,3,3-tetrafluoropropene unit. <8>According to the 8th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 5th to 7th aspects, wherein the content of the vinylidene fluoride unit in the segment A of the above polymer is 99 to 15 mol% relative to all monomer units constituting the segment A. <9>According to the 9th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 1st to 8th aspects, wherein the segment B of the above polymer contains a fluorine-containing monomer unit. <10>According to the 10th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 1st to 9th aspects, wherein the segment B of the above polymer contains a vinylidene fluoride unit. <11>According to the 11th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to the 10th aspect, wherein the content of the vinylidene fluoride unit in the segment B of the above polymer is 97 mol% or more relative to all monomer units constituting the segment B. <12>According to the 12th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 1st to 11th aspects, wherein, the segment B of the above polymer contains only a vinylidene fluoride unit, or contains a vinylidene fluoride unit and at least one monomer unit selected from the group consisting of a tetrafluoroethylene unit, a hexafluoropropylene unit, a 2,3,3,3-tetrafluoropropene unit, and a (meth)acrylic acid unit. <13>According to the 13th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 1st to 12th aspects, wherein the mass ratio of the segment A to the segment B in the above polymer is 40 / 60 to 95 / 5. <14>According to the 14th aspect of the present invention, There is provided a binder for a non-aqueous electrolyte battery according to any one of the 1st to 13th aspects, wherein, The above polymer contains a chain structure represented by the general formula (1) or the general formula (2), General formula (1): A-B-A, General formula (2): B-A-B (In the formula, A represents segment A and B represents segment B), The segment A of the above polymer has a glass transition temperature of -10°C or lower, and contains vinylidene fluoride units and 2,3,3,3-tetrafluoropropene units. The content of 2,3,3,3-tetrafluoropropene units in segment A is 18 to 30 mol% relative to all monomer units constituting segment A, and the content of vinylidene fluoride units in segment A is 70 to 82 mol% relative to all monomer units constituting segment A. The segment B of the above polymer has a melting point of 140 to 200°C, and contains vinylidene fluoride units. The content of vinylidene fluoride units in segment B is 97 mol% or more relative to all monomer units constituting segment B. The mass ratio of segment A to segment B in the above polymer is 50 / 50 to 90 / 10, The weight average molecular weight of the above polymer is 200,000 to 2,000,000. <15>According to the 15th aspect of the present invention, there is provided a binder for non-aqueous electrolyte battery, which contains a polymer. The above polymer has a glass transition temperature and a melting point, contains 2,3,3,3-tetrafluoropropene units, and the extraction amount with tetrahydrofuran at 25°C is 5% by mass or less. <16>According to the 16th aspect of the present invention, there is provided the binder for non-aqueous electrolyte battery of the 15th aspect, wherein the above polymer further contains vinylidene fluoride units. <17>According to the 17th aspect of the present invention, there is provided the binder for non-aqueous electrolyte battery of the 15th or 16th aspect, wherein the above polymer contains two or more segments. <18>According to the 18th aspect of the present invention, there is provided the binder for non-aqueous electrolyte battery of any one of the 15th to 17th aspects, wherein, the glass transition temperature of the above polymer is -10°C or lower, the melting point of the above polymer is 140 to 200°C, The above-mentioned polymer contains vinylidene fluoride units and 2,3,3,3-tetrafluoropropene units. The content of 2,3,3,3-tetrafluoropropene units is 9 to 24 mol% relative to all monomer units constituting the above-mentioned polymer, and the content of vinylidene fluoride units is 76 to 91 mol% relative to all monomer units constituting the above-mentioned polymer. The extraction amount of tetrahydrofuran at 25 °C of the above-mentioned polymer is 2 to 4% by mass. The weight average molecular weight of the above-mentioned polymer is 200,000 to 2,000,000. <19>According to the 19th aspect of the present invention, There is provided an electrode binder for a non-aqueous electrolyte battery, which contains the binder for a non-aqueous electrolyte battery according to any one of the 1st to 18th aspects. <20>According to the 20th aspect of the present invention, There is provided the electrode binder for a non-aqueous electrolyte battery according to the 19th aspect, which further contains a powder electrode material and water or a non-aqueous solvent. <21>According to the 21st aspect of the present invention, There is provided an electrode for a non-aqueous electrolyte battery, which includes an electrode material layer formed of the electrode binder according to the 19th or 20th aspect. <22>According to the 22nd aspect of the present invention, There is provided a non-aqueous electrolyte battery, which includes the electrode according to the 21st aspect. [Examples]

[0198] Next, examples will be given to illustrate the embodiments of the present invention, but the present invention is not limited to these examples.

[0199] Each value in the examples was measured by the following methods.

[0200] <Polymer composition> The composition of the fluorine-containing copolymer and PVdF was measured by solution NMR method. Measuring device: VNMRS400 manufactured by Varian Resonance frequency: 376.04 (Sfrq) Pulse width: 30° (pw = 6.8)

[0201] <Content of monomer units containing polar groups in PVdF> The content of monomer units with polar groups (acrylic acid units, maleic acid, etc.) in PVdF is measured by acid-base titration of carboxyl groups. Specifically, about 0.5 g of PVdF is dissolved in acetone at a temperature of 70 to 80 °C. 5 ml of water is added dropwise under rapid stirring to avoid solidification of PVdF. Titration is carried out using an aqueous NaOH solution with a concentration of 0.1 N, and a neutral transformation occurs at about -270 mV until the acidity is completely neutralized. Based on the measurement results, the amount of substance of monomer units with polar groups contained in 1 g of PVdF is determined, and thus the content of monomer units with polar groups is calculated.

[0202] <Weight-average molecular weight> The weight-average molecular weight of PVdF is measured by gel permeation chromatography (GPC). It is calculated based on the data measured by using TSKgel AS-8010, CO-8020 manufactured by Tosoh Corporation, columns (3 GMHHR-H columns connected in series), and RID-10A manufactured by Shimadzu Corporation, with dimethylformamide (DMF) flowing as a solvent at a flow rate of 1.0 ml / min (reference: polystyrene). Furthermore, regarding the weight-average molecular weight of the fluorine-containing copolymer, based on the results measured by the GPC method, the molecular weight is calculated with reference to standard polystyrene. GPC device: TOSOH HLC-8320GPC Columns: 1 SuperAW-H, 3 SuperAWM-H Eluent: Dimethylformamide [DMF] Sample concentration: 0.05 mass% Measurement temperature: 40 °C

[0203] <Storage modulus (E')> The storage modulus is the value measured by dynamic viscoelasticity measurement at 30 °C or 60 °C. Using the dynamic viscoelasticity device DVA220 manufactured by Japan IT Measurement & Control Corporation, for a specimen with a length of 30 mm, a width of 5 mm, and a thickness of 50 to 100 μm, measurement is carried out under the conditions of a tensile mode, a clamping width of 20 mm, a measurement temperature range from -30 °C to 160 °C, a heating rate of 2 °C / min, and a frequency of 1 Hz.

[0204] The test piece used for measurement was produced by the following method: PVdF was dissolved in N-methyl-2-pyrrolidone (NMP) at a concentration of 10 to 20% by mass to obtain a solution, the obtained solution was poured onto a glass plate and dried at 100 °C for 12 hours, and then further dried at 100 °C under vacuum for 12 hours. The obtained film with a thickness of 50 to 100 μm was cut into a length of 30 mm and a width of 5 mm.

[0205] <Melting point> Using a differential scanning calorimetry (DSC) device, the temperature corresponding to the peak of the endothermic curve when the sample was heated from 30 °C to 220 °C at a rate of 10 °C / minute was obtained as the melting point.

[0206] <Glass transition temperature (Tg)> Using a differential scanning calorimeter (DSC822e manufactured by Mettler-Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science), 10 mg of the sample was heated at a rate of 20 °C / minute to obtain a DSC curve. The temperature at the intersection of the extension line of the baseline before and after the second transition of the DSC curve and the tangent line at the inflection point of the DSC curve was taken as the glass transition temperature.

[0207] <Heat of fusion> Using a differential scanning calorimeter (DSC822e manufactured by Mettler-Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science), the sample was heated from 30 °C to 220 °C at a rate of 10 °C / minute, and the heat of fusion was calculated based on the magnitude of the melting peak (ΔH) of the obtained endothermic curve.

[0208] <THF extraction amount> To 1 g of the polymer obtained in each example, 9 g of tetrahydrofuran (THF) was added and stirred at 25 °C using a stirrer. After 24 hours, the solid components were filtered out, the solution was dried, and the weight of the dried product was measured to calculate the extraction amount (the ratio (mass%) of the weight of the dried product to the weight of the polymer (1 g)).

[0209] <Viscosity change rate of the positive electrode binder> Using a Type B viscometer (DV2T manufactured by Brookfield), the viscosity of the positive electrode mixture was measured 10 minutes after the start of measurement at 25°C, with the main spindle LV-04 (64) and a rotational speed of 6 rpm. After preparing the positive electrode mixture, based on the viscosity of the positive electrode mixture measured immediately (η0) and the viscosity after 24 hours at a storage temperature of 50°C after preparing the mixture (η24), the viscosity change rate (X24) was calculated using the following formula. Xn = η24 / η0 × 100 [%]

[0210] <Peeling Strength between the Positive Electrode Material Layer and the Positive Electrode Current Collector of the Positive Electrode> A test piece of 1.2 cm × 7.0 cm was prepared by cutting a positive electrode with a positive electrode material layer on one side. After fixing the positive electrode material layer side of the test piece to a movable jig with double-sided tape, a tape was attached to the surface of the positive electrode current collector, and the stress (N / cm) was measured using a stereoplotter when the tape was stretched to 90 degrees at a speed of 100 mm / min. The load cell of the stereoplotter used was 1 N.

[0211] <Maximum Test Force> The bending strength (three-point bending test) was measured according to the method of ASTM D790. Test pieces were prepared by cutting a positive electrode with positive electrode material layers on both sides or a negative electrode with negative electrode material layers on both sides into a size of 15 mm × 20 mm. Using the three-point bending method, the test piece was placed between the first and second points at an interval of 10 mm, and the center of the test piece (the third point) was pressed in the thickness direction of the test piece at a fixed speed using a probe to perform a bending test (bending property test). For the third point, while it was moving in the thickness direction at a moving speed of 5 mm / min, the applied force was measured. The maximum bending strength (maximum bending force or maximum bending strength) is the maximum value of the force applied to the test piece according to the moving distance of the probe.

[0212] <Half Width> The bending strength (three-point bending test) was measured according to the method of ASTM D790. Test pieces were prepared by cutting a positive electrode having a positive electrode material layer on both sides or a negative electrode having a negative electrode material layer on both sides into a size of 15 mm × 20 mm. Using the three-point bending method, the test piece was placed between the first point and the second point at an interval of 10 mm, and the center (the third point) of the test piece was pressed in the thickness direction of the test piece at a fixed speed using a probe to conduct a bending test (bending property test). For the third point, while moving at a moving speed of 5 mm / min in the thickness direction, the applied force was measured. The maximum bending force or maximum bending strength is the maximum value of the force applied to the test piece according to the moving distance of the probe. Subsequently, the test force that is half of the maximum bending strength is calculated, and "the distance from the stroke at which the test force first reaches half of the maximum bending strength when the test force gradually increases after the start of the test to the stroke at which the test force reaches half of the maximum bending strength when the test force gradually decreases after reaching the maximum test force" is the half-width. That is, a curve can be plotted with the stroke of the stereoplotter as the horizontal axis and the stress as the vertical axis, and it is specified as the peak width when the stress is half of the peak.

[0213] In the examples and comparative examples, the following polymers were used.

[0214] PVdF A: VdF homopolymer Weight average molecular weight 900000 Storage modulus at 30°C 1740 MPa Storage modulus at 60°C 1140 MPa Melting point 171°C B: VdF homopolymer Weight average molecular weight 1800000 Storage modulus at 30°C 1820 MPa Storage modulus at 60°C 1180 MPa Melting point 171°C C: PVdF containing acrylic acid units Content of acrylic acid units 1.0 mol% Weight average molecular weight 1100000 Storage modulus at 30°C 1280 MPa Storage modulus at 60°C: 720 MPa Melting point: 161°C D: PVdF containing maleic acid units Content of maleic acid units: 0.5 mol% Weight-average molecular weight: 900000 Storage modulus at 30°C: 1260 MPa Storage modulus at 60°C: 760 MPa Melting point: 167°C E: PVdF containing CTFE units Content of CTFE units: 2.4 mol% Weight-average molecular weight: 800000 Storage modulus at 30°C: 1250 MPa Storage modulus at 60°C: 880 MPa Melting point: 168°C F: PVdF containing HFP units and acrylic acid units VdF / HFP = 97.5 / 2.5 (mol%) Content of acrylic acid units: 1.0 mol% Weight-average molecular weight: 1110000 Storage modulus at 30°C: 1080 MPa Storage modulus at 60°C: 750 MPa Melting point: 150°C

[0215] Production Example 1 Fluorine-containing copolymer a (Production of (B-A-B block polymer) (where A represents segment A and B represents segment B)) (Step 1) Into a 6 L stainless steel autoclave, 4000 ml of pure water, a 50% aqueous solution of 0.8001 g of CH₂=CFCF₂OCF(CF₃)CF₂OCF(CF₃)COONH₄, and a 50% aqueous solution of 24.021 g of C₅F₁₁COONH₄ were added, and nitrogen substitution was carried out. VdF was slightly pressurized, stirred at 400 rpm, and the temperature was simultaneously adjusted to 80 °C. VdF was pressured in until 1.64 MPa, and a mixed monomer solution with a molar ratio of VdF to 2,3,3,3-tetrafluoropropene (R1234yf) of 77.2 / 22.8 was further pressured in until 2.001 MPa. Polymerization was initiated by pressuring in a solution obtained by dissolving 0.16 g of ammonium persulfate in 4 ml of pure water using nitrogen pressure. When 24 g of the mixed monomer was reached, 1.009 g of 1,4-diiodoperfluorobutane was added. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa using the mixed monomer, and this operation was repeated. When 1020 g had been added, the gas in the autoclave was released until 0.05 MPa, and then heat treatment was carried out for 3 hours. 10 g was sampled from the dispersion in the autoclave and dried, and the composition of the obtained polymer was VdF / R1234yf = 77.6 / 22.4 in molar ratio, the glass transition temperature was -12.5 °C, and there was no heat of fusion.

[0216] (Step 2) After the heat treatment in Step 1, the autoclave was maintained at 80 °C, VdF was pressured in until 2.003 MPa, and polymerization was initiated by pressuring in a solution obtained by dissolving 0.08 g of ammonium persulfate in 4 ml of pure water using nitrogen pressure. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa using VdF, and this operation was repeated. When 180 g had been added, the gas in the autoclave was released and cooled, and 5270 g of the dispersion was recovered. The solid content of the dispersion was 23.83 mass%.

[0217] Aluminum sulfate was added to the dispersion, coagulation was carried out, and it was dried, whereby 1250 g of the polymer was obtained. The composition of the obtained block polymer was VdF / R1234yf = 82.0 / 18.0 in molar ratio, and the content ratio of segment B calculated from the composition was 17.2 mass%. The weight average molecular weight Mw was 1.266 million, the glass transition temperature was -12.9 °C, the melting point was 160.3 °C, and the heat of fusion was 8.2 mJ / mg. Also, the THF extraction amount was 3 mass%.

[0218] Production Example 2 Fluorine-containing copolymer b (Production of B-A-B block polymer (where A represents segment A and B represents segment B)) Except for changing the monomer addition amount of the mixed solution in Step 1 from 1020 g to 900 g and changing the VdF addition amount in Step 2 from 180 g to 300 g, a dispersion of 5236 g was recovered in the same order as in Production Example 1. The solid content of the dispersion was 24.10% by mass.

[0219] Aluminum sulfate was added to the dispersion, coagulation was carried out, and it was dried to obtain 1257 g of a polymer. The composition of the obtained block polymer was VdF / R1234yf = 84.2 / 15.8 in molar ratio, and the content ratio of segment B calculated from the composition was 28.1% by mass. The weight average molecular weight Mw was 1.206 million, the glass transition temperature was -11.0 °C, the melting point was 161.1 °C, and the heat of fusion was 11.0 mJ / mg. Also, the THF extraction amount was 3% by mass.

[0220] Production Example 3 Fluorine-containing copolymer c (Production of B-A-B block polymer (where A represents segment A and B represents segment B)) Except for changing the monomer addition amount of the mixed solution in Step 1 from 1020 g to 780 g and changing the VdF addition amount in Step 2 from 180 g to 420 g, a dispersion of 5252 g was recovered in the same order as in Production Example 1. The solid content of the dispersion was 23.74 wt%.

[0221] Aluminum sulfate was added to the dispersion, coagulation was carried out, and it was dried to obtain 1250 g of a polymer. The composition of the obtained block polymer was VdF / R1234yf = 85.9 / 14.1 in molar ratio, and the content ratio of segment B calculated from the composition was 36.0% by mass. The weight average molecular weight Mw was 1.29 million, the glass transition temperature was -11.2 °C, the melting point was 161.4 °C, and the heat of fusion was 17.1 mJ / mg. Also, the THF extraction amount was 3% by mass.

[0222] Production Example 4 Fluorine-containing copolymer d (Production of A-B-A block polymer (where A represents segment A and B represents segment B)) (Step 1) To a 6 L stainless steel autoclave, 4000 ml of pure water, a 50% aqueous solution of 0.8003 g of CH₂=CFCF₂OCF(CF₃)CF₂OCF(CF₃)COONH₄, and a 50% aqueous solution of 24.014 g of C₅F₁₁COONH₄ were added, and nitrogen substitution was carried out. VdF was slightly pressurized, stirred at 400 rpm, and the temperature was simultaneously adjusted to 80°C. VdF was pressured in until 2.00 MPa. Polymerization was initiated by introducing, through nitrogen pressure, a solution obtained by dissolving 0.16 g of ammonium persulfate in 4 ml of pure water. When 24 g of VdF was reached, 1.009 g of 1,4-diiodoperfluorobutane was added. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa with VdF, and this operation was repeated. When 300 g had been added, the gas in the autoclave was released until 0.05 MPa, and then heat treatment was carried out for 3 hours. 10 g was sampled from the dispersion in the autoclave and dried, and the resulting polymer showed no observed glass transition temperature, had a melting point of 161.1°C, and a heat of fusion of 44.8 mJ / mg.

[0223] (Step 2) After the heat treatment in Step 1, the autoclave was maintained at 80°C. After VdF was pressured in until 1.64 MPa, a mixed monomer solution with a molar ratio of VdF / R1234yf of 77.5 / 22.5 was pressured in until 2.001 MPa. Polymerization was initiated by introducing, through nitrogen pressure, a solution obtained by dissolving 0.08 g of ammonium persulfate in 4 ml of pure water. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa with the mixed monomer solution, and this operation was repeated. When 900 g had been added, the gas in the autoclave was released and cooled, and 5271 g of the dispersion was recovered. The solid content of the dispersion was 23.80 mass%.

[0224] Aluminum sulfate was added to the dispersion, coagulated, and dried, and 1248 g of the polymer was obtained. The composition of the obtained block polymer was VdF / R1234yf = 82.7 / 17.3 in molar ratio, and the content ratio of segment B calculated from the composition was 24.1 mass%. The weight average molecular weight Mw was 1.426 million, the glass transition temperature was -10.4°C, the melting point was 160.8°C, and the heat of fusion was 10.8 mJ / mg. Also, the THF extraction amount was 3 mass%.

[0225] Examples 1 - 11, Comparative Examples 1 - 5 (Preparation of Binder Solution) The fluoropolymer and PVdF were dissolved in N-methyl-2-pyrrolidone (NMP) according to the composition (mass ratio) in Table 1 such that the concentration of the binder (fluoropolymer and PVdF) in the NMP solution became 7% by mass, thereby preparing a composition (binder solution).

[0226] (Preparation of Cathode Mix) The cathode active material (NMC (LiNi 0.9Mn 0.05Co 0.05O 2)) and the conductive agent (Super P Li, manufactured by TIMCAL) were added to the composition obtained by the above operation, and thoroughly mixed using a stirrer to prepare a cathode mix. The mass ratio of the cathode active material, the conductive agent, and the binder in the cathode mix was 97 / 1.5 / 1.5. Also, the solid content concentration in the cathode mix was 74% by mass.

[0227] (Fabrication of Cathode with Cathode Material Layer on One Side) The obtained cathode mix was uniformly coated on one side of a cathode current collector (aluminum foil with a thickness of 20 μm) such that the coating amount became 24.5 mg / cm 2. After completely volatilizing the NMP, a rolling press was used to apply a pressure of 10 t twice for pressing, thereby fabricating a cathode having a cathode material layer and a cathode current collector.

[0228] (Fabrication of Cathode with Cathode Material Layers on Both Sides) The obtained cathode mix was uniformly coated on both sides of a cathode current collector (aluminum foil with a thickness of 20 μm) such that the coating amount became 32.0 mg / cm 2 per side. After completely volatilizing the NMP, a rolling press was used to apply a pressure of 7 t for pressing, thereby fabricating a cathode having a cathode material layer and a cathode current collector.

[0229] The evaluation results of the cathode mix and the electrode are shown in Table 1.

[0230] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Binder PVdF A 80 45 100 B 8 55 80 100 C 80 90 100 E 100 F 100 Fluorinated copolymer a 100 20 b 100 55 c 100 92 45 20 d 100 20 10 Viscosity change rate (%) after storage at 50°C for 24 hours 145 153 122 156 212 190 118 121 178 193 171 >300 >300 >300 255 >300 Peel strength (N / cm) 0.40 0.46 0.47 0.41 0.33 0.39 0.37 0.39 0.34 0.51 0.57 0.23 0.28 0.54 0.11 0.46 Maximum test force (N) 0.90 0.99 0.89 1.04 1.10 1.05 0.91 1.01 1.13 1.10 1.18 1.28 1.33 1.34 1.19 1.23 Half width (mm) 5.98 5.81 5.85 6.19 3.35 4.02 5.45 4.28 3.65 3.71 3.12 2.82 2.71 2.68 1.94 2.02

[0231] Example 12 19.2 mass% of graphite-coated silicon oxide powder (powder with silicon oxide surface coated with graphite) as the negative electrode active material, 76.8 mass% of graphite powder, and 4.0 mass% of fluoropolymer c (7% NMP solution) as the binder were mixed, and an appropriate amount of NMP was further added to prepare a negative electrode mixture slurry. Subsequently, the negative electrode mixture slurry was coated on both sides of a negative electrode current collector composed of a copper foil and dried. It was cut into a specific electrode size and rolled with a rolling press at a pressure of 10 t to fabricate a negative electrode having a negative electrode material layer formed on both sides of the negative electrode current collector. The evaluation results are shown in Table 2.

[0232] Example 13 A negative electrode was fabricated by the same operation as in Example 12, except that 48.0 mass% of graphite-coated silicon oxide powder and 48.0 mass% of graphite powder were used as the negative electrode active material, and 0.8 mass% of PVdF A and 3.2 mass% of fluoropolymer c were used as the binder. The evaluation results are shown in Table 2.

[0233] Comparative Example 6 A negative electrode was fabricated by the same operation as in Example 12, except that polyacrylic acid (manufactured by Aldrich, weight average molecular weight 450,000) was used as the binder. The evaluation results are shown in Table 2.

[0234] Comparative Example 7 A negative electrode was fabricated by the same operation as in Example 13, except that styrene-butadiene rubber (TRD2001 manufactured by JSR Corporation) was used as the binder. The evaluation results are shown in Table 2.

[0235] [Table 2] Example 12 Example 13 Comparative Example 6 Comparative Example 7 Binder PVdF A 0 20 0 0 Fluoropolymer c 100 80 0 0 Polyacrylic acid 0 0 100 0 Styrene-butadiene rubber 0 0 0 100 Graphite powder / graphite-coated silicon oxide powder (Mass ratio) 80 / 20 50 / 50 80 / 20 50 / 50 Maximum test force (N) 0.24 0.28 0.46 0.34 Half-width (mm) 4.1 3.5 1.4 2.5

[0236] Example 14 Except for using 19.2 mass% of silicon powder and 76.8 mass% of graphite powder as the negative electrode active material, a negative electrode was produced by the same operation as in Example 12. The evaluation results are shown in Table 3.

[0237] Example 15 Except for using 47.5 mass% of silicon powder and 47.5 mass% of graphite powder as the negative electrode active material, a negative electrode was produced by the same operation as in Example 13. The evaluation results are shown in Table 3.

[0238] Comparative Example 8 Except for using styrene-butadiene rubber (TRD2001 manufactured by JSR Corporation) as the binder, a negative electrode was produced by the same operation as in Example 14. The evaluation results are shown in Table 3.

[0239] Comparative Example 9 Except for using polyacrylic acid (manufactured by Aldrich, weight-average molecular weight 450,000) as the binder, the negative electrode was fabricated by the same operation as in Example 15. The evaluation results are shown in Table 3.

[0240] [Table 3] Example 14 Example 15 Comparative Example 8 Comparative Example 9 Binder PVdF A 0 20 0 0 Fluorine-containing copolymer c 100 80 0 0 Polyacrylic acid 0 0 0 100 Styrene-butadiene rubber 0 0 100 0 Graphite powder / silicon powder (Mass ratio) 80 / 20 50 / 50 80 / 20 50 / 50 Maximum test force (N) 0.32 0.36 0.41 0.55 Half-width (mm) 3.5 3.1 2.3 1.6

Claims

1. A binder for non-aqueous electrolyte batteries, comprising a polymer, the polymer comprising a segment A having a glass transition temperature below 25°C and a segment B having a melting point above 50°C, wherein segment A of the polymer comprises vinylidene fluoride units and at least one of the group consisting of repeating units selected from any of the following formulas: Formula: -CH2-CFRf 1- (wherein Rf 1 is a straight-chain or branched fluorinated alkyl or fluorinated alkoxy group having 1 to 12 carbon atoms, and when the number of carbon atoms is 2 or more, it may contain oxygen atoms between carbon atoms), Formula: -CHF-CHRf 2- (wherein Rf 2 is a straight-chain or branched fluorinated alkyl or fluorinated alkoxy group having 1 to 12 carbon atoms, and when the number of carbon atoms is 2 or more, it may contain oxygen atoms between carbon atoms), and segment B of the polymer comprises vinylidene fluoride units. The content of the vinylidene fluoride unit in segment A of the polymer is 15 to 94 mol% relative to all monomer units constituting segment A, and the content of the vinylidene fluoride unit in segment B of the polymer is 97 mol% or more relative to all monomer units constituting segment B.

2. The binder for non-aqueous electrolyte batteries as described in claim 1, wherein, Segment A has a heat of fusion of less than 5 J / g, while segment B has a heat of fusion of more than 5 J / g.

3. The binder for non-aqueous electrolyte batteries as requested in item 1 or 2, wherein, The polymers described above contain chain structures represented by general formula (1) or general formula (2), general formula (1): ABA, general formula (2): BAB (where A represents chain segment A and B represents chain segment B).

4. The binder for non-aqueous electrolyte batteries as claimed in claim 1 or 2, wherein, Segment A of the polymer contains vinylidene fluoride units and 2,3,3,3-tetrafluoropropylene units.

5. The binder for non-aqueous electrolyte batteries as claimed in claim 1 or 2, wherein, Segment B of the above polymer contains only vinylidene fluoride units, or contains vinylidene fluoride units and at least one monomer unit selected from the group consisting of tetrafluoroethylene units, hexafluoropropylene units, 2,3,3,3-tetrafluoropropylene units and (meth)acrylic acid units.

6. The binder for non-aqueous electrolyte batteries as claimed in claim 1 or 2, wherein, The mass ratio of segment A to segment B in the above polymer is 40 / 60 to 95 / 5.

7. The binder for non-aqueous electrolyte batteries as claimed in claim 1 or 2, wherein, The polymer described above contains a chain structure represented by general formula (1) or general formula (2), general formula (1): ABA, general formula (2): BAB (where A represents chain segment A and B represents chain segment B). Chain segment A of the polymer described above has a glass transition temperature below -10°C and contains vinylidene fluoride units and 2,3,3,3-tetrafluoropropylene units. The content of 2,3,3,3-tetrafluoropropylene units in chain segment A is 18-30 mol% relative to all monomer units constituting chain segment A, and the content of vinylidene fluoride units in chain segment A is 70-82 mol% relative to all monomer units constituting chain segment A. Chain segment B of the polymer described above has a melting point of 140-200°C and contains vinylidene fluoride units. The content of vinylidene fluoride units in chain segment B is 97 mol% or more relative to all monomer units constituting chain segment B. The mass ratio of segment A to segment B in the above polymer is 50 / 50 to 90 / 10, and the weight average molecular weight of the above polymer is 200,000 to 2,000,000.

8. A binder for a non-aqueous electrolyte battery, comprising a polymer having a glass transition temperature below -10°C, a melting point of 140–200°C, the polymer comprising vinylidene fluoride units and 2,3,3,3-tetrafluoropropylene units, wherein the content of 2,3,3,3-tetrafluoropropylene units is 9–24 mol% relative to all monomer units constituting the polymer, the content of vinylidene fluoride units is 76–91 mol% relative to all monomer units constituting the polymer, the tetrahydrofuran extractability of the polymer at 25°C is 2–4 wt%, and the weight average molecular weight of the polymer is 200,000–2,000,000.

9. The binder for non-aqueous electrolyte batteries as described in claim 8, wherein, The polymers mentioned above contain two or more chain segments.

10. An electrode binder for a non-aqueous electrolyte battery, comprising the binder for a non-aqueous electrolyte battery of claim 1 or 8.

11. The electrode mixture for non-aqueous electrolyte batteries as claimed in claim 10, further comprising powdered electrode material and water or non-aqueous solvent.

12. An electrode for a non-aqueous electrolyte battery, comprising an electrode material layer formed of the electrode compound of claim 10.

13. A non-aqueous electrolyte battery having the electrodes of claim 12.