WO2006025602A1

WO2006025602A1 - Process for producing positive electrode material composition for lithium secondary battery

Info

Publication number: WO2006025602A1
Application number: PCT/JP2005/016469
Authority: WO
Inventors: Alan Vallee; Paul-Andre Lavoie; Fumihide Tamura; Izuho Okada; Kazuo Takei; Masamitsu Sasaki; Taketo Toba
Original assignee: Nippon Shokubai Co., Ltd.
Priority date: 2004-09-03
Filing date: 2005-09-01
Publication date: 2006-03-09
Also published as: JPWO2006025602A1

Abstract

A process for producing a positive electrode material composition for lithium secondary battery, in which a positive electrode material composition containing a polymer, an electrode active material, a conduction aid and an electrolyte salt compound and being capable of easily forming a positive electrode portion of lithium secondary battery exhibiting excellent battery performance can be obtained securely at high productivity. There is provided a process for producing a positive electrode material composition for lithium secondary battery, the positive electrode material composition comprising a polymer, an electrolyte salt compound, an electrode active material and a conduction aid as essential components, characterized in that mixing of the electrolyte salt compound, electrode active material and conduction aid with the polymer is carried out in two separate steps consisting of the step (I) of first mixing only the electrolyte salt compound in dissolved form in the polymer and the step (II) of in the mixture resulting from the mixing of the electrolyte salt compound in the polymer, simultaneously or sequentially mixing the electrode active material and the conduction aid.

Description

Method of manufacturing positive electrode material composition for lithium secondary battery

The present invention relates to a method for producing a positive electrode material composition used for producing a positive electrode portion of a lithium secondary battery. Background art

The positive electrode portion of the lithium secondary battery includes a polymer constituting the matrix structure, an electrode active material (metal oxide) for storing Li.sup. +, A conductive aid for assisting the movement of bright electrons, and an electrolyte. A lithium salt (electrolyte salt compound), which is a source of L i + to be dissociated, is an essential component.

book

In general, the positive electrode portion of a lithium secondary battery is obtained through the process of preparing a material composition containing such components. Specifically, (i) the components are melt-kneaded, and (2) See, for example, Patent Documents 1 and 2. (ii) These components are mixed in the presence of a solvent, made into a slurry, cast into a mold of a predetermined shape, It is obtained by performing a method of volatilizing (see, for example, Patent Documents 3 and 4).

[Patent Document 1] International Publication No. 0 3 7 5 3 7 5 Pamphlet

[Patent Document 2] International Publication No. 0 3 Z 9 2 0 1 7 Pamphlet

[Patent Document 3] Special Table 2 0 0 2-5 3 5 2 3 5

[Patent Document 4] US Patent No. 5 7 5 5 8 5 5 Disclosure of the Invention Problems to be Solved by the Invention

By the way, in order to exhibit excellent battery performance, it is important that the above-mentioned respective components be sufficiently uniformly mixed, but generally, lithium salts to be electrolyte salt compounds are other essential components. It was difficult to mix uniformly with the components. Therefore, in the conventional method, for example, the essential components other than the electrolyte salt compound are mixed in advance, and the lithium salt is melt-kneaded in the mixture when the mixture is extruded. However, in order to mix lithium salt uniformly, it is necessary to carry out melt-kneading under severe conditions such as high heat quantity or high shear force, which causes an excessive shear, so polymer degradation and deterioration ( Specifically, there is a problem that the reduction of the weight average molecular weight becomes remarkable, and as a result, the battery performance is reduced. Also, in the conventional method, a polar solvent which is relatively easy to dissolve lithium salt or a mixed solvent containing a large amount of polar solvent (specifically, a mixed solvent with a nonpolar solvent in which 85% by weight or more is a polar solvent) An attempt has been made to achieve uniformity by mixing it with other essential components in a state in which the lithium salt is dissolved), but when a large amount of polar solvent is mixed in the positive electrode material, the battery performance is significantly reduced. There is a problem, if you try to remove polar solvent strictly after mixing to avoid this problem, time and cost will be significantly Productivity was to be lost.

Therefore, the problem to be solved by the present invention is to easily form a positive electrode portion of a lithium secondary battery that exhibits excellent battery performance, which contains a polymer, an electrode active material, a conductive auxiliary agent and an electrolytic salt compound. It is an object of the present invention to provide a method for producing a positive electrode material composition for lithium secondary battery, which can reliably obtain a positive electrode material composition which can be produced with good productivity. Means to solve the problem

The present inventors diligently studied to solve the above-mentioned problems. As a result, when mixing the polymer, the electrode active material, the conductive aid and the electrolyte salt compound, the electrolyte salt compound to the polymer, the electrode active material and the conductive aid are first mixed with the polymer only with the electrolyte salt compound. By separately performing the step of mixing in a dissolved state (I) and the step of mixing the electrode active material and the conductive auxiliary agent into a mixture of the polymer and the electrolyte salt compound, a large amount of polar solvent is not used. It was also found that the lithium salt can be dissolved and then uniform mixing with other essential components can be easily achieved under relatively mild conditions. And, according to such a method, the present invention was completed after confirming that the above problems could be solved at once.

That is, a method of producing a positive electrode material composition for a lithium secondary battery according to the present invention comprises the steps of: obtaining a positive electrode material composition comprising a polymer, an electrolyte salt compound, an electrode active material and a conductive additive as essential components; The mixing of the electrolyte salt compound, the electrode active material and the conductive auxiliary agent with respect to the polymer is performed by first mixing only the electrolyte salt compound in a solution with the polymer (I) and mixing the electrolyte salt compound into the polymer It is characterized in that it is divided into the step (II) of mixing the active material and the conductive additive simultaneously or before or after. Effect of the invention

According to the present invention, the positive electrode portion of a lithium secondary battery exhibiting excellent battery performance can be easily produced. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the method for producing the positive electrode material composition for a lithium secondary battery according to the present invention (hereinafter, sometimes referred to as “the production method of the present invention”) will be described in detail. There is no restriction, and modifications can be made as appropriate without departing from the spirit of the present invention other than the following examples.

In the production method of the present invention, as described above, in obtaining a positive electrode material composition comprising a polymer, an electrolyte salt compound, an electrode active material and a conductive aid as essential components, the electrolyte salt compound for the polymer, The step (I) of mixing only the electrolyte chloride in solution with the mixture of the electrode active material and the conductive aid first in solution and the electrode active material and the conductive aid in the mixture after mixing the electrolyte salt compound with the polymer It is important to carry out separately in the step (II) of mixing simultaneously or back and forth.

Hereinafter, first, the step (I) and the step (II) which are essential steps in the production method of the present invention will be described in detail, and then various steps which can be adopted in the production method of the present invention will also be described. [Step (I) and Step (II)]

In step (I), first, only the electrolyte salt compound is dissolved and mixed in the polymer. In detail, mixing in a solution state means that the electrolyte salt compound is dissolved in the polymer medium to make the electrolyte salt compound and the polymer in a uniform mixture. Here, the polymer medium specifically means a polymer solution or a polymer itself which has been heated and melted, and in the case of using the polymer solution as a medium, step (I) indicates the presence of a solvent. In the case where the molten polymer itself is used as the medium, step (I) is carried out in the absence of a solvent.

The polymer solution is a solution in which a polymer is dissolved in a solvent, and as the polymer solution, for example, a reaction solution after polymerization reaction obtained when a polymer is synthesized by a solution polymerization method, or A solution obtained by isolating a polymer synthesized by precipitation polymerization or the like and dissolving it in a solvent capable of dissolving it is preferably used. Among them, since the solution polymerization method is excellent in productivity and is also excellent in safety because it is easy to remove heat of reaction, it is more preferable to use the reaction solution obtained by the method as a polymer solution.

The solvent which can be used for the above polymer solution (for example, when the reaction solution obtained by the solution polymerization method is used as a polymer solution, the solvent which can be used for the polymerization reaction) reacts with the polymerization catalyst to cause a side reaction It is preferable to use a solvent which does not have active hydrogen which may adversely affect battery performance, a functional group having a carbon atom which can be polarized and negative, etc. Specifically, for example, benzene, toluene, xylene and ethylbenzene Aromatic hydrocarbon solvents such as: heptane, octane

Aliphatic hydrocarbon solvents such as n-hexane, n-pentane and 2, 2, 4-trimethylpentane; alicyclic hydrocarbon solvents such as cyclohexane, cyclopentane and methylcyclohexane; Ether solvents such as dibutyl ether and methyl butyl ether; Solvents of ethylenediaryldialkyl ethers such as dimethoxetane; Cyclic ether solvents such as THF (tetrahydrofuran) and dioxan; Active solvents such as hydroxyl group such as hydroxyl group Among them, toluene and xylene are more preferable, and those containing no water are particularly preferable.

The content ratio of the polymer in the polymer solution is not limited, but is preferably 20% by weight or more, more preferably 25% by weight or more, still more preferably 30% by weight or more. If the content of the polymer is less than 20% by weight, the amount of polymer in the step (I) decreases, and in order to sufficiently mix the electrolyte salt compound in the step (I), the temperature or the temperature at that time It may be necessary to make conditions of time equal strictly or it may become difficult to dissolve the electrolyte salt compound even if the conditions are strict. Furthermore, for example, when the reaction solution obtained by the solution polymerization method or the like is used as a polymer solution, the productivity of the polymer and the productivity of the target positive electrode material composition may be extremely reduced.

The content of the solvent in the polymer solution is preferably, but not limited to, 80% by weight or less, more preferably 75% by weight. /. The content is more preferably 70% by weight or less. When the content of the solvent exceeds 80% by weight, the amount of the solvent contained in the mixture obtained in step (I) increases, and in order to sufficiently mix the electrolyte salt compound in step (I), In such a case, it may be necessary to make conditions such as temperature and time stricter, or it may be difficult to dissolve the electrolytic salt compound even if the conditions are strict. Furthermore, for example, When the reaction solution obtained by the solution polymerization method or the like is used as a polymer solution, the productivity of the polymer, and hence the productivity of the intended positive electrode material composition may be extremely reduced.

The polymer solution may contain other components in addition to the polymer and the solvent, and examples thereof include an initiator, an antioxidant, a solubilizer and the like generally used in the polymerization reaction. Examples of the above reaction initiator include alkaline catalysts such as sodium hydroxide, potassium hydroxide, potassium alcoholate, sodium alcoholate, potassium carbonate and sodium carbonate, and metals such as, for example, potassium metal and sodium metal, for example, water Aluminum oxide / calcined magnesium (Japanese Patent Application Laid-Open No. Hei 8-2 689 1 9 etc.), Metal-ion-added magnesium oxide (Japanese Patent Publication No. Hei 6-150 8, Japanese Patent Application Laid-Open No. Hei 7-2 2 7 5 Catalysts such as A 1-M g-based composite oxide catalysts such as JP-A No. 40 and the like, and calcined hyd- ide-talcite (JP-A Nos. 2-7, 8 6- 3 3 4 7 8 2), iridium oxide, barium hydroxide (JP-A 5-54 1 5 8 7 etc.), layered compounds (Japanese Patent Publication 6- 5 0 5 5 9 8 6), Stronchi Oxides, strontium hydroxides (JP-B 6 3 3 0 5 5 etc.), calcium compounds (JP-A 2 3 4 3 6 6 etc), cesium compounds (JP-A 7- 7 7 Preferred examples thereof include complex metal cyanide complexes (Japanese Patent Application Laid-Open No. 5-33961 etc.), acid catalysts such as Lewis acids and Friedel-Crafts catalysts, and the like. These initiators and other components may be contained alone or in combination of two or more in the polymer solution, and are not limited.

Although the viscosity of the polymer solution is not limited, it is preferable that the viscosity is 1, 000 to 60, 00 centi- ces at 95 ° C, and more preferably 10, 0 0 at 95 ° C. It is 0 to 4 5 0 0 0 0, preferably 15 0 0 to 0 3 5 0 0 0 0 0 centi- voise at 95 ° C. When the above viscosity is less than 1,000 centipoise at 95 ° C., for example, when the reaction solution obtained by the solution polymerization method is used as a polymer solution, the productivity of the polymer and thus the target positive electrode If the productivity of the material composition may be extremely reduced, and the temperature exceeds 600 centioise at 95 ° C., for example, the reaction solution obtained by the solution polymerization method is used as the polymer solution In the process (I), when mixing the electrolyte salt compound with the polymer solution or the polymer itself in the molten state, the mixing may be difficult. The procedure such as heating and the like is not particularly limited. For example, in the case of using a polymer solution as a medium, the polymer is dissolved in a solvent, and the electrolyte chloride is added and dissolved therein. May be, allowed to dissolve by the addition of pre electrolyte salt compound in a solvent, it may be dissolved by adding the polymer therein. When the polymer itself which has been heated and melted is used as a medium, the polymer may be heated and brought into a molten state, and the electrolyte salt compound may be added and dissolved therein, or it may be previously solidified. After the electrolyte salt compound is mixed with the polymer of the body, it may be heated to simultaneously melt the polymer and dissolve the electrolyte salt compound.

In the step (I), when mixing the electrolyte salt compound with the polymer solution or the polymer itself in the molten state, the polymer solution is heated and melted in order to dissolve and mix more uniformly when using the polymer solution as a medium. In the case where the polymer itself is used as a medium, it is preferable to appropriately heat and mix in order to maintain the molten state and to uniformly mix and mix. The temperature during heating is If the lima solution is used as the medium, the boiling point of the solvent may be taken into consideration, and if the polymer itself in the molten state is used as the medium, the melting temperature of the polymer may be taken into consideration.

For example, 3 0 to: I 10 should be good.

The mixing method in the step (I) is not particularly limited, and a mixing method using a conventionally known mixing apparatus or an apparatus capable of mixing is preferable. As a mixing apparatus etc. which can be used, what is necessary is just an apparatus capable of mixing and stirring the contents charged in the container, and an apparatus capable of carrying out mixing and stirring of contents under desired conditions by mounting a stirring blade is preferable. For example, a stirrer with an anchor blade, a stirrer with a helical ribbon blade, a stirrer with a double helical ribbon blade, a stirrer with a helical screw blade with a draft tube, a super blend blade (inner blade: Max-blended wing, Max-blended wing (for example, Super Blend, manufactured by Sumitomo Heavy Industries, Ltd.), Max-blended wing (Sumitomo Heavy Industries, Ltd.) Stirring device equipped with a full zone wing (Shinko Pantech Co., Ltd.), stirring machine equipped with a super mix wing (Satake Chemical Machinery Co., Ltd.), 1 ^ _ mixer (Shonken Chemical Co., Ltd.) Stirrer equipped with a company), Stirrer equipped with a Sanmera wing (Mitsubishi Heavy Industries), Log bone (Shinko Pantech Co., Ltd.) Made of VCR (Mitsubishi Heavy Industries, Ltd.), torsion grid blades (manufactured by Hitachi, Ltd.), turbine blades, paddle blades, fadler blades, bull margin blades, propeller blades, etc. Among them, a paddle-shaped concentric biaxial stirring device equipped with a super blend blade, a stirring device equipped with a helicanolone blade, a stirring device equipped with a double helix ribbon blade, and a Max Blend blade More preferably, the stirring device equipped with the gimbal is mounted. In addition to horizontal-type stirring devices, horizontal stirring-mixing devices equipped with a screw pattern for kneading, for example, KRC kneader (manufactured by Kurimoto Co., Ltd.), twin-screw extruder (for example, Product name: SUPERTEX a II, manufactured by Japan Steel Works Co., Ltd .; Product name: BT-30-S 2, manufactured by Plastic Science Research Institute, and the like. In particular, when mixing is carried out in the absence of a solvent (when the polymer itself used as a medium is used as the medium), it is preferable to use an extruder.

In the step (I I), the electrode active material and the conductive auxiliary agent are mixed with the mixture obtained by mixing the electrolyte salt compound with the polymer. This step (II) may be performed after the above-mentioned step (I), and may be performed after the above-mentioned step (I), or may be performed after the above-mentioned step (I) A step (for example, a cooling / solidifying step described later, a granulation step, a drying and / or a humidity control step, etc.) may be performed and then performed. In other words, the mixture after the electrolyte salt compound is mixed with the above-mentioned polymer may be in a liquid state or in a solidified state, and if it is a liquid, it contains a solvent. It may or may not be contained. However, when the mixture is in a solidified form, in order to uniformly mix the electrode active material and the conductive auxiliary, in the step (II), the polymer in the mixture can be maintained in a molten state. It is preferable to use a solvent as described later.

When mixing the electrode active material and the conductive auxiliary agent into the mixture after mixing the polymer with the electrolyte salt compound in the step (II), the electrode active material and the conductive auxiliary agent should be mixed simultaneously or before or after the mixing. The mixing procedure is not particularly limited. For example, The electrode active material and the conductive additive may be simultaneously added to the mixture and mixed, or the electrode active material and the conductive additive may be separately added to the mixture and mixed, or The electrode active material and the conductive additive may be mixed and then added to and mixed with the mixture.

In the step (I I), a solvent can be used when mixing the electrode active material and the conductive aid. As a solvent which can be used by mixing of process (II), although limitation is not carried out, For example, What was mentioned above as a solvent which can be used for a polymer solution, etc. are mentioned. When a solvent is used in the mixing of step (II), for example, the force of adding the solvent to the electrode active material and / or the conductive aid, the solvent separately from the electrode active material and the conductive aid It may be added. When a solvent is used in step (II), the amount thereof used is not limited, but the amount of solvent contained in the mixture obtained in step (II) (here, the amount of solvent is, for example, the polymer solution in step (I) When used as a medium, the total amount including the solvent in the polymer solution

It is preferable that 30) to 80% by weight, more preferably 35 to 75% by weight, and still more preferably 40 to 70% by weight. If the amount of solvent contained in the mixture obtained in step (II) is less than 30% by weight, the viscosity becomes high and mixing and stirring become difficult, and it is also difficult to send or transfer the liquid to the mixing apparatus itself. In addition, excessive shear may occur during mixing, which may promote polymer degradation and molecular weight reduction. On the other hand, if it exceeds 80% by weight, the amount of solvent contained in the mixture obtained after step (II) increases, and even if each component can be sufficiently uniformly mixed in step (II), There is a risk of impairing productivity, for example, it takes a long time to devolatize the solvent in the subsequent steps such as step (III).

In the production method of the present invention, it is possible to uniformly disperse and mix the essential components, the polymer, the electrolyte salt compound, the electrode active material and the conductive auxiliary agent, to obtain excellent battery performance (for example, cycle characteristics (charge and discharge characteristics). And the like) is desirable in that it can obtain a positive electrode material composition that exhibits. In addition, when the polymer, the electrolyte salt compound, the electrode active material, and the conductive auxiliary agent are not uniformly dispersed and mixed, there is a problem that an extruder may cause clogging when forming a film of the obtained positive electrode material composition. It will also lead you. The mixing of the step (I) mentioned above is to mix the electrolyte salt compound in a dissolved state with respect to the polymer, and although the mixture obtained by the mixing of the step (I) is uniform, the step (II) The mixture obtained by mixing is usually in the form of a slurry. Therefore, in the production method of the present invention, when the electrode active material and the conductive auxiliary agent are mixed in the step (II), a uniform dispersed slurry state is obtained, in other words, the electrode active material and the conductive support agent. It is preferable to use a slurry that contains as little as possible of agent aggregates. Specifically, the amount of aggregates in the mixture obtained in step (II) is preferably 5% by weight or less, more preferably 3% by weight or less, and still more preferably 1% by weight or less. Good. In the present invention, a method of evaluating whether or not a uniform dispersion state · Criteria and a method of measuring the content of aggregates will be described in the examples described later.

In the step (II), in order to obtain a slurry in a uniformly dispersed state, for example, by appropriately setting the use conditions (for example, the type of the stirring blade, the rotation speed, etc.) of the mixing device used for mixing, etc. In the step (II), in particular, the electrode active material and the conductive aid are previously added to the solvent and uniformly dispersed (in other words, the aggregate is contained as much as possible). It can be easily achieved by putting it in the form of a slurry and mixing it with the mixture obtained in step (I). Here, it is important that the slurry-like premix prepared by adding the electrode active material and the conductive aid in advance to the solvent be in a uniform dispersed state (in other words, a state in which the aggregates are not contained as much as possible). For this purpose, (i) adjusting the concentration of the electrode active material and the conductive aid in the above-mentioned mixture, (ii) using the polymer solution as a medium in the step (I), Improving the compatibility between the electrode active material and the conductive aid and the solvent by mixing the polymer solution or a part of the mixture obtained in step (I) with the electrode active material and the conductive aid in advance; Or it is effective to use (i) and (ii) together. In (i), the concentrations of the electrode active material and the conductive aid in the pre-mixture are

It is preferably 25 to 55% by weight, more preferably 30 to 50% by weight, and still more preferably 35 to 45% by weight. In (ii), the amount of the polymer solution previously mixed with the electrode active material and the conductive aid or the amount of the mixture obtained in step (I) is the polymer solution in the polymer solution or the mixture obtained in step (I) The solid content is 0.1 to 10% by weight, preferably 0.5 to 7% by weight, with respect to the pre-blend. / _0, more preferably it is preferable to make a 2-7% by weight.

The mixing method in the step (II) is not particularly limited, and a mixing method using a conventionally known mixing apparatus or a compatible apparatus is preferable. As a mixing apparatus and the like that can be used, any apparatus can be used as long as it can mix and stir the contents charged in the container, and an apparatus that can be equipped with a stirring blade and can mix and stir the contents arbitrarily under desired conditions is preferable. For example, a stirrer equipped with an anchor blade, a mixer equipped with a helical ribbon blade, a stirrer equipped with a double helical ribbon blade, a mixer equipped with a helical screw blade with a draft channel, a super blend blade (inner blade: Matsux Blended wing, Outer wing: Spiral-type concentric twin-screw stirring device (for example, product name: Sue 'per blend, made by Sumitomo Heavy Industries, Ltd.), Max-blended wing (Sumitomo Heavy Industries) Stirring device equipped with a full zone wing (Shinko Pantech Co., Ltd.), Stirring device equipped with a super mix wing (Satake Chemical Machinery Co., Ltd.), Hi _ FS Kicer (Shonken Chemical Co., Ltd.) Stirrer equipped with a company), Stirrer equipped with a Sanmera wing (Mitsubishi Heavy Industries), Log bone (Shinko Pantec Stirring device with VCR (Mitsubishi Heavy Industries, Ltd.), twisting grid blade (Hitachi, Ltd.), turbine blade, paddle blade, paddle roller blade, bull margin blade, propeller blade, etc. Among them, a paddle-shaped concentric biaxial stirring device equipped with a super-blend blade, a stirring device equipped with a helical ribbon blade, a stirring device equipped with a double helix ribbon blade, and a Max blend blade are particularly preferred. The mounted stirring apparatus and the stirring apparatus mounted with log bone are more preferable. In addition to horizontal-type stirring devices, horizontal stirring-mixing devices equipped with a screw pattern for mixing, such as KRC kneader (manufactured by Kurimoto R & D Co., Ltd.), twin-screw extruder (for example, Product name: SUPERTEX α II, manufactured by Japan Steel Works, Ltd .; Product name: BT-30_S2, manufactured by Plastic Engineering Research Institute, and the like. In particular, the step (II) is carried out in the absence of a solvent (using the polymer itself brought into a molten state in the step (I) as a medium and carrying out the step (II) following the step (I) or In the case where the polymer solution is used as a medium, and the step (II) is carried out without using the solvent after the step (III) to be described later on after the step (I), etc.

It is preferable to use an extruder at the time of performing the mixing in the above. The polymer used as an essential component in the present invention is not particularly limited, but is preferably a polyether polymer of ion conductivity. Examples of the ionically conductive polyether polymer include ethylene oxide copolymers (nonionic alkylene oxide water soluble copolymers) and the like. The polymers may be used alone or in combination of two or more.

The ethylene oxide-based copolymer is not limited as long as it is a polymer having mainly an ethylene oxide monomer-derived constituent component in its molecular structure and having an ether bond in the main chain. For example, as a raw material monomer, ethylene oxide and the following structural formula (1):

(Wherein, Ra is any one of an alkyl group having 1 to 16 carbon atoms, a cycloalkyl group, a aryl group, an aryl group, a (meth) aryloyl group and an alkenyl group) others - CH ₂ -0-Re-Ra group (Re is - 0) (p has the structure of p- integer) from 0 to 10 - (C¾- CH ₂₎ a substituted Okishiran compound represented by) Polymers obtained by polymerizing comonomers containing are preferred. It is preferable that this polymerization be ring-opening polymerization of the oxsilane group of each raw material monomer.

The group in the above structural formula (1) is a substituent in the above-mentioned substituted oxylan compound. Examples of the substituted oxysilane compound represented by the above structural formula (1) include propylene oxide, butylene oxide, 1, 2-epoxypentane, 1, Examples thereof include 2-epoxyhexane, 1,2-epoxyoctane, cyclohexenoxide and styrene oxide, or methyl glycidyl ether, hydroxyethyl glycidyl ether, ethylene glycol methyl glycidyl ether, etc. In the case of a crosslinkable substituent, that is, in the case where the substituent has an aryl group, an alkenyl group, an acryloyl group or a methacryloyl group, etc., epoxybutene, 3, 4 _ epoxy 1 pentene, 1, 2 _ epoxy one 5, 9-cyclo dodecadi 1, 3, 4-epoxy-1-vinylcyclohexene, 1, 2-epoxy-5-cyclo-Otaten, glycidyl acrylohydrate グリシジ, glycidyl methacrylate, glycidyl sorbate and glycidyl -4-hexanoate, or vinylaldehyde Sidyl ether, aryl glycidyl ether, 4-vinylcyclohexyl glycidyl ether, α-terpenyl dalysyl ether, cyclohexenyl methyl daricidyl ether, 4-vinyl benzyl glycidyl ether, 4-aryl benzyl glycidyl ether, etc. Can also be mentioned. The substituted oxylan compounds used as the raw material monomers may be used alone or in combination of two or more.

As the above-mentioned substituted oxylan compound, it is essential to use a substituted oxylan compound having the above-mentioned cross-linking substituent (substituent R 1 is a cross-linking substituent), and it is possible to cross-link the ethylene oxide copolymer Preferred for use in The weight average molecular weight (Mw) of the ethylene oxide copolymer is not limited, but is preferably 20,000 to 500,000, more preferably 30,000 to 300,000, still more preferably 40,000. It is 000-200,000. If the weight-average molecular weight is less than 20,000, the positive electrode material after molding may be tacked. If the weight-average molecular weight exceeds 500,000, the positive electrode material is difficult to be molded, and the processability and handling are low. There is a risk of

The molecular weight distribution (MwZMn) of the ethylene oxide copolymer is not limited, but is preferably 3 or less, more preferably 2 or less. If the molecular weight distribution is more than 3, tackiness may occur in the molded positive electrode material, handling may be deteriorated, and the content of low molecular weight substances may be increased to lower the battery performance.

The proportion of the polymer used is not limited, but is preferably 15 to 60% by weight, and more preferably 20 to 60% by weight, based on the total amount (total amount of all the raw materials used in mixing step (I)). It is 55 wt%, more preferably 25 to 50 wt%. If the amount of the polymer is too small, the productivity of the positive electrode material composition is extremely reduced, and in order to sufficiently mix the electrolyte salt compound in the step (I), the conditions such as temperature and time are strict. It is possible that it may be difficult to dissolve the electrolyte salt compound even if the conditions are strict, but if the amount of the polymer is too large, the electrolyte active material or the electrolyte salt compound may There is a risk that the uniform dispersion may decrease, and the viscosity may increase, which may make it difficult to mix and stir.

The electrolyte salt compound used as an essential component in the present invention may be a lithium salt generally used for the positive electrode of a lithium secondary battery, and is not limited, for example, fluorine ion, chlorine ion, bromine ion, Iodine ion, heptafluoropropyl sulfonic acid ion, bis (trifluoromethanesulfonyl) imide ion, bis (hepta fluoropropyone / les norejo: ^ イミ imide ion, trifno reo loth norephonide ion, tetraf / Leo-borate borate ion, nitrate ion, As F _6- , PF ₆ , stearyl sulfonate ion, octyl sulfonate ion, dodecyl benzene sulfonate ion, naphthalene sulfonate ion, dodecyl naphthalene sulfonate ion and 7, 7, 8 , 8-Tetrasiano p-quinodi Methane ion And at least one anion selected from the group consisting, salts consisting of a lithium ion (L i +) as the cation are preferably mentioned, among _{others, L i BF 4, L i} PF 6, L i CF _{_{_{3 S0 3, L i C 4}}} F 9 S0 3, L i N (CF 3 S0 2) 2 and _{_{L i N (C 2 F 6}} S0 2) 2 are more preferred. electrolyte salt compound is used alone You may use two or more kinds together.

Although the use ratio of the electrolyte salt compound is not limited, for example, the molar ratio of the oxygen atom in the polymer (for example, the oxygen atom in the polyether skeleton) to the lithium atom in the electrolyte salt compound (lithium salt) OZL i) Power:! It is preferable to set to -36, more preferably 3 to 33, and still more preferably 6 to 30. If the amount of the electrolyte salt compound is too small, the ion conductivity may be lowered. On the other hand, if the amount of the electrolyte salt compound is too large, the effect of improving the ion conductivity can not be recognized even if it is added more. In general, the electrode active material used as an essential component in the present invention is a host that has an activity of accepting lithium ions as a guest in order to insert and desorb lithium ions. It means a compound, and an electromotive force, a reaction amount (energy 'density), reversibility required in a lithium secondary battery, and reversibility. It is an essential component to obtain ion conductivity. Compounds that receive lithium ion as a guest include titanium sulfide (T i S ₃ , T i S ₂ ), vanadium oxide (V ₂ 0 ₅ ), manganese oxide (Mn 0 ₂ ), niobium selenide ((Nb S e ₃ ), various complex oxides containing lithium as a metal element (L i C 0 0 ₂ , L i N i 0 ₂ , L i Mn ₂ 0 ₄ , L i F e 0 ₂ etc.), etc. may be mentioned. The electrode active material that can be used in the mixing step in the step is not particularly limited as long as it is generally used for the positive electrode of a lithium secondary battery, but, for example, lithium vanadium composite oxide, lithium cobalt composite oxide, lithium Manganese complex oxides, lithium nickel complex oxides, vanadium oxide, etc. may be mentioned, but among them, lithium vanadium complex oxides, that is, Li _x V _y O _z (where x, y and z are respectively Each other alone , And 0 <x y 2, y = (mx + 2 z) Zn and z = (mx + ny) / 2 (where m is the valence of Li, n is the valence of V and is 4 or more) It is a real number of) It is a real number that satisfies) Force) Introduction of lithium ion · Desorption is performed more efficiently, and large capacity

(High energy density) is particularly preferred. The electrode active material may be used alone or in combination of two or more. The electrode active material used is generally in the form of solid powder, and

(I I) It will be in the state of being dispersed in the mixture obtained later.

The use ratio of the electrode active material is not limited, but is preferably, for example, 0.1 to 50 times by weight, more preferably 0.3 to 20 times, still more preferably, based on the weight of the polymer. Should be between 0.5 and 10 times. If the amount of the electrode active material is too small, the function as the positive electrode may not be sufficiently exhibited. On the other hand, if the amount of the electrode active material is too large, molding of the positive electrode material may be difficult.

The conductive assistant used as an essential component in the present invention may be any one as long as it is usually used for a positive electrode of a lithium secondary battery, and is not limited. For example, acetylene black, ketjen black, Graphite etc. It can be mentioned. The conductive aid may be used alone or in combination of two or more. The conductive aid to be used is generally in the form of a solid powder and is in the state of being dispersed in the mixture obtained after step (II).

The proportion of the conductive aid is not limited, but is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight, with respect to 100 parts by weight of the electrode active material. It is good to be. If the amount of the conductive additive is too small, the conductivity of the positive electrode may be insufficient. If the amount of the conductive additive is too large, the forming of the positive electrode material may be difficult.

In the production method of the present invention, it is preferable to carry out both or one of the step (I) and the step (II) in the presence of a solvent. This makes it possible to perform uniform mixing easily. Specifically, when the step (I) is carried out in the presence of a solvent, for example, the case of using a polymer solution as a medium can be mentioned. When step (II) is carried out in the presence of a solvent, for example, (i) when using the solvent in step (II) as described above, (ii) using the polymer solution as a medium in step (I) and In the case where the step (II) is carried out following the step (I) (in other words, the step (III) described later before the step (II) is not performed), (iii) the polymer solution is used as a medium in the step (I) Use and force to carry out step (III) to be described later prior to step (II) In the step (III), the solvent may not be completely volatilized. When both or one of the step (I) and the step (II) is carried out in the presence of a solvent, the mixture obtained after the step carried out in the presence of a solvent does not lose fluidity. It is preferable to also include a step (III) of volatilizing the solvent (this step (III) may also be referred to as a "volatilization step"). Hereinafter, the degassing step will be described in detail.

[Process (ι ι ι〕)]

In the step (III), the solvent is evaporated from the mixture containing the solvent obtained in the step carried out in the presence of a solvent, for example, under the conditions of heating and the like to volatilize the solvent to obtain a fluidizable state. Degassing should be stopped when it is maintained. The mixture obtained after volatilization may generally be one containing no solvent or one adjusted to a desired solvent concentration, and is not limited, but the latter is preferred.

As a method of devolatilization, an apparatus used for devolatilization and various conditions, a method which can be taken during normal devolatilization, an apparatus which can be used, conditions to be set, etc. may be adopted, but there is no particular limitation. For example, as described below.

As a method of devolatilization, usually, there are two steps of pre-volatilization and main devolatilization, and as a procedure of devolatilization, it is preferable to carry out the pre-volatilization after the pre-volatilization but this is not limited Alternatively, it may be carried out as a one-step process without distinction between pre-volatilization and full-volatilization. The division into two stages is preferable because the efficiency of devolatilization (cost reduction, shortening of processing time, quality of polymer, etc.) becomes possible. Specifically, (a) It is possible to perform annealing and degassing after the solvent content contained in the mixture before degassing has been rapidly reduced to such an amount that the solvent can be efficiently removed. The equipment size can be made smaller than in the case of single stage treatment by pressure degassing and subsequent vacuum (depressurization) degassing. (C) At the time of devolatilization, viscosity may rapidly rise in a certain concentration range Although the drive system can be made smaller than in the case of processing in a single stage, etc., it is theoretically preferable due to reasons such as, but depending on the type of mixture to be subjected to the degassing treatment (especially the type of polymer) Even the two-step process The same effect may be obtained, and it may be selected appropriately according to the object to be treated. The device (degassing device) to be used for degassing is not limited. Among them are stirring vessel evaporators, downstream liquid column evaporators, thin film evaporators, surface renewal type polymerizers, kneaders, roll mixers, intensive mixers (so-called Banbury-one mixers), extruders, etc. Preferably, it is carried out using at least one device. In addition, the usage conditions can be set appropriately depending on the device used.

Stirred tank evaporators are excellent in that they can cope with a wide range of viscosity and a wide range of residual solvent concentration. For example, a stirring tank equipped with a helical ribbon blade, a stirred tank equipped with a double helical ribbon blade, a super blend blade冀: Max blend wing, Outer wing: Helical deformation baffle) Vertical twin screw mixing tank (for example, Product name: Super blend, made by Sumitomo Heavy Industries, Ltd.), VCR reverse conical ribbon wing reactor (Mitsubishi Heavy Industries Ltd. make) etc. are mentioned preferably. These can be used for both batch processing and continuous processing, but are more preferably used for batch processing. In addition, because of the characteristics of the device, it takes a lot of time to discharge after treatment, so it is preferable to correspond to the process of accurately processing a small amount rather than the process of processing a large amount of polymer and the like. Also, if you use these, The heat transfer is performed by heat transfer surface renewal.

Among the various stirring vessel evaporators described above, in particular, with regard to a bowl-shaped concentric twin-screw stirring vessel, the following (i)

Excellent features such as (vi) can be mentioned. (I) The treatment viscosity range is wide, and it is possible to exhibit excellent mixing performance in the viscosity range of 1 to 10 0 0 0 0, (ii) following the rapid viscosity change in the tank Because the mixing function of the inner and outer wings changes naturally, it is possible to maintain a good flow state because it responds. (I ii) uniform the liquid flow velocity on the inner wall of the tank and the inner center of the tank Can maintain high temperature uniformity and reduce the degradation of polymer quality, (iv) the slippage and retention of low viscosity liquid on high viscosity fluid are eliminated, reflux reflux liquid and after polymerization Can improve the dispersibility of various additives, etc., (V) can prevent adhesion and deposition on the tank wall and baffle part during high concentration slurry processing, and show good slurry dispersibility, (Vi) Stable wall velocity by rotating the outer wing close to the tank wall As a result, the adhesion of the inner wall and the cleaning time in the tank can be reduced.

As a downstream liquid column evaporator, a multi-tubular heat exchanger type (for example, product name: Sulza-I mixer, manufactured by Sumitomo Heavy Industries, Ltd .; product name: static mixer, manufactured by Noritake), plate heat exchange Container type (for example, product name: Hiviscous Evaporator, manufactured by Mitsui Shipbuilding Co., Ltd.) is preferably mentioned. They can be used for both batch and continuous processes, and both processes can be performed successfully. Furthermore, due to the characteristics of the device, devolatization by these causes sensible heat to be applied, and then converts the sensible heat into latent heat under reduced pressure to evaporate, so the amount that can be volatilized is sensible heat heating (transfer as latent heat It depends on the amount of heat that can be Therefore, a process with a throughput corresponding to the amount of sensible heat is preferable. However, in the multi-tubular heat exchanger type, since the heat transfer can be promoted by a stick mixer, a process with a wide range of throughputs is possible. It is also possible to Moreover, in the case of a multi-tubular heat exchanger type, the evaporation process is carried out by interface area expansion, and the corresponding maximum processing viscosity is preferably 5 0 0 0 0, and in the case of a plate heat exchanger type The evaporation process is performed by heat transfer area expansion, and the corresponding maximum processing viscosity is preferably 10 0 0 0 0 boise.

The thin film evaporator is excellent in that a centrifugal force is exerted by a blade and a uniform liquid film can be formed. For example, a horizontal thin film evaporator (for example, product name: Eva reactor, manufactured by Kansai Chemical Machinery Co., Ltd.), fixed Blade type vertical thin film evaporator (for example, product name: EXEVA, manufactured by Shinko Pantec Co., Ltd.), movable blade type vertical thin film evaporator (for example, product name: Wipelen, manufactured by Shinko Pantech Co., Ltd.) Preferred are a tank type (mirror type) thin film evaporator (for example, product name: recovery, manufactured by Kansai Chemical Machinery Co., Ltd.). With regard to batch processing, it is possible to use horizontal type or tank type ones, though it is not common, and wedge type ones are not possible regardless of fixed blade type or movable blade type. Also, all continuous processing is possible. Due to the characteristics of the equipment, all of these degassing is performed by heating with sensible heat and then converting the sensible heat to latent heat under reduced pressure to evaporate, so the amount that can be devolatilized is transferred as the sensible heat heating amount It depends on the amount of heat to be obtained. Therefore, it is preferable to use a process with a throughput corresponding to the amount of sensible heat. And all this, the evaporation process is done by the transfer surface renewal.

Horizontal type thin film evaporators are more difficult to cope with high viscosity on the discharge side than vertical type, so a blade with excellent discharge effect is used to be able to cope with high viscosity. Is preferably 500 boise. The vertical thin film evaporator is a low viscosity liquid because it descends by its own weight. It is preferred that the higher maximum viscosity of the movable blade type is 1,200 Boise, although the higher viscosity liquid is more suitable. In addition, in the fixed blade type, the fixed blade is made to have a downward effect so as to correspond to a high viscosity, and the corresponding maximum processing viscosity is preferably 10 0 0 0 Boise. The tank type thin film evaporator can suppress the short path of the low viscosity liquid by using a mirror, and the corresponding maximum processing viscosity is preferably 1,200 boise.

The surface renewal type polymerizer (horizontal type thin film polymerizer) is excellent in that it shows high degassing performance by the renewal of the gas and liquid surface. For example, a uniaxial surface type surface renewal type polymerizer, a biaxial type surface renewal type polymerizer (For example, Product name: Bipolac, manufactured by Sumitomo Heavy Industries, Ltd. '; Product name: Hitachi glasses wing polymerizer, manufactured by Hitachi Ltd .; Product name: Hitachi grid wing polymerizer, manufactured by Hitachi Ltd. Product name: SC processor, manufactured by Kurimoto Co., Ltd., and the like. These are not possible for batch processing, and all for continuous processing. Due to the characteristics of the equipment, the throughput of devolatilization is all dependent on the transfer rate of the substance in the equipment, and the evaporation process is carried out by gas-liquid surface renewal.

Kneader (For example, Product name: K R C kneader, manufactured by Kurimoto Koji Co., Ltd.), roll mixer

An intensive mixer (so-called Banbury-one mixer), like an extruder, is suitable for mixing high-viscosity melts and the like, and has a degassing ability as an additional function. These can be processed both batchwise and continuously. For these, it is preferred that the corresponding maximum processing viscosity is 10 0 0 0 Boise.

The single-shaft type exhibits high degassing performance because it can ensure efficient surface area, and the corresponding maximum processing viscosity is preferably 10 0 0 0 boise. The biaxial type is excellent in self-creeping property and liquid retention control due to no dead space in the container and high biston flow property, and the corresponding maximum processing viscosity is 10 0 0 0 0 It is preferable to have one.

The extruder is suitable for mixing such as melt viscosity, and has an addition function of heating, melting, kneading and degassing ability. For example, a single-screw extruder, a twin-screw extruder (for example, product name) : SUPERTEX a II, manufactured by Japan Steel Works, Ltd .; Product name: BT-30-S 2, Plastics Research Institute, SCR self-cleaning reactor (Mitsubishi Heavy Industries Ltd.), etc. are preferably mentioned. . These can not be processed batchwise, and can be processed continuously. Due to the characteristics of the apparatus, as described above, these are suitable for the process of degassing the object with very high viscosity, and the evaporation process is performed by kneading and evaporation. In the extruder, both of the single-screw type and the twin-screw type, the corresponding maximum processing viscosity is preferably 100, 00 Boise.

As described above, the preferred method of devolatilization can be exemplified by the method of volatilization after pre-volatilization, but among the above-mentioned various devolatilization apparatuses, those which can be preferably used for pre-volatilization are limited. Although it does not work, it has a stirring tank equipped with a helical ribbon blade, a mixing tank equipped with a double-helical ribbon blade, a vertical concentric biaxial mixing tank equipped with a super blend blade, a mixing tank equipped with a Max Blend blade, and a log bone blade. It includes a stirring vessel, a plate heat exchanger type downstream liquid column evaporator, and a fixed blade type vertical thin film evaporator. In addition, what can be used for this devolatilization may be, but is not limited to, a twin-screw surface renewal type polymerizer, a kneader, a twin-screw extruder and the like. In the case of carrying out the degassing in the step (III), the various degassing apparatuses listed above may be directly connected to the so-called upstream apparatus used in the step carried out immediately before the step (III) to carry out the degassing. The process

It is also possible to carry out the devolatilization by various devolatilizers after liquid transfer or transfer from the pre-stage apparatus used in the step performed immediately before (I I I). For the former, for example, various liquid transfer pumps (eg gear pump (trade name: gear pump, manufactured by Shimadzu Corp.), mono pump) (eg product name: mono pump, hijishin equipment And the like)). As for the latter, for example, there is a form in which a liquid transfer line is connected between the pre-stage device and the degassing device, and an intermediate tank tank equipped with a jacket and a stirrer between the pre-stage device and the degassing device The form etc. which provided the cushion tank are mentioned.

In the step (III), the concentration of the residual solvent in the mixture after volatilization is preferably 0.01 to 30% by weight, more preferably 0.5 to 20% by weight, and further preferably Or 0.1 to 10% by weight. When the residual solvent concentration is less than 0.01% by weight,

Since it is necessary to make the conditions for volatilization stricter, it may lead to thermal degradation of the mixture (especially polymer) obtained after volatilization, which may in turn reduce the battery performance of the battery produced by the intended positive electrode material composition. If the amount is more than 30% by weight, the target positive electrode material composition may be tacked to cause blocking or the like, or the battery performance may be deteriorated.

In the step (II I), it is preferable to adjust the water content of the mixture after volatilization simultaneously with volatilizing the solvent. Water is contained, for example, in the monomers and solvents used in the polymerization reaction. Specifically, it is preferable to adjust the water content to 5,00 0 p p m or less, more preferably 5 0 0 p p m or less, and still more preferably 2 0 0 p p m or less. When the water content exceeds the above range, the lithium salt may react with the water content when used in a lithium secondary battery, and the ion conductivity may not be sufficiently exhibited.

The means for adjusting the water content is not limited. For example, it is preferable to increase the devolatilization temperature and to increase the degree of pressure reduction during the devolatization treatment (note that the degree of pressure reduction is not limited). To increase the pressure means to lower the pressure, and to reduce the degree of pressure reduction means to increase the pressure.) When adjusting the water content by raising the volatilization temperature, the temperature is not limited, but if it is too low, it is not efficient because it is necessary to increase the degree of pressure reduction excessively, and it is too high Since heat deterioration of the mixture (especially polymer) obtained after volatilization may occur, these should be taken into consideration and appropriately set. In addition, when adjusting the water content by increasing the degree of pressure reduction for volatilization, the degree of pressure reduction is not limited, but if it is too large, it is considered difficult in consideration of the sealing performance of the degassing apparatus. If it is too small, it may not be possible to control the water content to 200 ppm or less unless the temperature of volatilization is increased considerably. Therefore, set appropriately taking these into consideration.

When the degassing step is carried out under heating conditions, the temperature is preferably 40 to 200 ° C, more preferably 55 to 175 ° C, still more preferably 70 ~ At 150. By degassing in this temperature range, after degassing, a mixture of the desired residual solvent concentration and the water content can be obtained. If the temperature is less than 40 ° C., the remaining solvent may increase. If the temperature exceeds 200 ° C., the mixture (particularly the polymer) obtained after devolatilization may be thermally degraded. There is. Here, the above-mentioned temperature means the temperature of the mixture when a stirred tank evaporator is used, and other devolatilizers (for example, a surface renewal type polymerizer, a kneader, and the like) When an extruder or the like is used, it is the temperature of the jacket of the degassing device and the heater portion.

Degassing is preferably carried out under a pressure of 1,000 to 100,000 Pa, more preferably 2,500 to 70,000 Pa, still more preferably 5, 000 to 40, OOO Pa . By degassing in this pressure range, after degassing, a mixture of the desired residual solvent concentration and the water content can be obtained. If the pressure is less than 1, OOOP a, the solvent may flash and foaming may occur, and if it exceeds 100, OOO Pa, the mixture (in particular, the polymer) obtained after devolatilization may be decomposed. In some cases, the temperature must be increased. Here, the pressure is the pressure in the tank of the degassing apparatus. In step (III), the viscosity of the mixture obtained after the degassing is such that the viscosity at 100 is 1,000 to 5,000 boise. It is preferable that the temperature is 100 ° C., preferably 5,000 to 4,000,000 Boise, and still more preferably 100, 10,000 to 30,000 Boise. When the viscosity is less than 1,000 at 100 ° C., the amount of the remaining solvent increases, and foaming and tack may occur when the target positive electrode material composition is formed. If it exceeds 000 000, degassing with the degassing apparatus may be difficult.

In the production method of the present invention, the step of cooling and solidifying the mixture to be the positive electrode material composition (this step is referred to as “cooling and solidifying step”), and the step of granulating the mixture (this step is It is preferable to also include at least one of the following steps: drying and / or conditioning the mixture (referred to as “drying and conditioning step”). Specifically, when one or both of the step (I) and the step (II) are performed in the presence of a solvent, at least one of the cooling and solidification step, the granulation step, and the drying / humidifying step is It may be performed at any time, but preferably after step (III). On the other hand, when both the step (I) and the step (II) are carried out in the absence of a solvent, at least one of the cooling and solidification step, the granulation step, the drying and humidity control step is the step I) and after step (II). The cooling / solidifying step, the granulation step, and the drying Z humidity control step may be performed in any order, but are preferably performed in the order described. Hereinafter, the cooling and solidification process, the granulation process, the drying z humidity control process, and the processes associated with these processes will be described in detail.

[Cooling and solidification process]

The cooling and solidification step is for cooling and solidifying (hardening) the mixture to be the positive electrode material composition. Since the mixture to be subjected to the cooling and solidifying step is, for example, a mixture obtained after the step (III), degassing is generally performed under heating, the steps (I) and steps (B) performed in the absence of a solvent II) If the mixture obtained later is heated so as to maintain the molten state of the polymer, it is in a warm state and in a state of low shape retention ability, for example, the polymer in the mixture is melted and It can be considered that it is in a state of being dry, or a state in which such a mixture is merely shaped (a state in which the shape has been imparted but has not been solidified). Specifically, the mixture to be subjected to the cooling / solidifying step is preferably in the state of 40 to 200 ° C., more preferably in the state of 55 to 175, still more preferably 70 to 150 ° C. It is in the state of C.

The method of cooling and solidification in the cooling and solidification step is not limited, but, for example, the mixture Preferred is a method of cooling and solidifying by contacting with a metal plate, a method of cooling and solidifying by directly applying cold air to the mixture, or a method of using these in combination.

When the cooling and solidification process is performed by contacting with a metal plate, the metal plate which can be used is not limited, but, for example, a drum cooler (for example, TUBAKO KEICHI 's product, product name: COMPACT CONTI COOLER; Product name: Drum cooler DC; made by Modern Chemical Engineering Co., Ltd .; product name: Laminator) Single belt cooler (For example, product made by Sandvik, product name: Steel belt crusher; Nippon Steel Co., Ltd.) Conveyer Co., Ltd. product name: Steel belt single cooler) Double steel belt cooler (For example, Sandvik Co., Ltd. Product name: Double steel belt cooler) Rolled double roll (For example, Kansai Roll Co., Ltd.) Product name: 8 x 20 box type roll machine), etc. It is preferable to cool the metal plate / metal surface to a desired temperature, for example, by spraying a coolant from the back side of the metal plate / metal surface. be able to.

The cooling temperature of the metal plate is not limited, and is preferably a temperature at which the polymer in the mixture to be solidified by cooling can be brought to a crystallization temperature and / or a temperature below the melting point, for example, The temperature is preferably 25 to 40 ° C, more preferably one 20 to 30 ° C, and still more preferably one 15 to 25 ° C. The lower the cooling temperature, the better. Furthermore, the temperature of the mixture to be solidified by cooling is preferably 50 ° C. or less, more preferably 45 ° C. or less, still more preferably 40 ° C. or less before cooling and solidifying. The mixture may be positively cooled by application or the like, or may be cooled by leaving, and the cooling means is not limited.), For example, the mixture can be easily peeled off from the metal plate after cooling and solidification. The cooled solidified product can be obtained in a stable yield.

When the cooling and solidification step is performed by direct application of cold air, the temperature and wind speed of the cold air are not limited, and the polymer in the mixture to be solidified by cooling is brought to a crystallization temperature and a temperature below melting point or melting point. It is preferable that the temperature and the wind speed can be used. For example, in the case of a sheet (plate) -like mixture (for example, a shape such as 2 mm × 2 5 O mm × 2 5 mm), it is preferable to apply a cold wind of about 9 ° C. at a wind speed of about 1 mZ seconds. If the mixture is in the form of blocks (lumps, cylinders) (for example, a shape with a diameter of 25 mm x 100 mm), the cold wind at about 5 to 10 ° C. is applied at a wind speed of 1 to 15 seconds. It should be applied by the degree.

The mixture to be subjected to the cooling and solidification process is discharged onto a metal plate, a metal surface or the like, and then conveyed while being cooled and solidified. Among the above cooling devices, a double steel belt cooler 1, a single belt cooler, a drum cooler and a rolling double roll (for example, Kansai Roll Co., Ltd. product name: 8 X 20 BOX type roll machine) were used. In the case of selecting the type of cooling belt, temperature of refrigerant, choice of refrigerant type, and width of T-die and width of double steel, etc., it is possible to easily obtain the conditions of any production volume.

In the production method of the present invention, in performing the cooling and solidification step, the force to form the mixture to be subjected to cooling and solidification in advance before cooling and solidification, or the molding step at the same time as cooling and solidification (forming step) You may have.

As a specific example of the above-mentioned forming step, for example, (i) The mixture is formed into a sheet, a string (strand), a plate, a particle, a rod, a block (block) etc. in advance by an extruder or the like. You A step of cooling with cold air, (ii) a step of pouring the mixture into a container for forming a mold in advance, and a step of forming the mixture, and (iii) a mixture as it is on a metal plate for cooling and solidification. A process of forming into a desired shape (eg, granular form, sheet form, etc.) simultaneously with making contact and making contact, and the like can be mentioned. As an example of the step (iii), the mixture is charged into a cylindrical drum having a plurality of holes (desired hole diameter) opened on its side, and this drum is rotated with its central axis (circular axis) horizontal, The process of forming into particles while cooling and solidifying can be mentioned by dripping from the holes onto a metal plate for cooling and solidifying.

Among the specific examples of the above-mentioned forming step, in order to obtain a molded product of the mixture with high productivity, in the step (i), it was taken out as a rod directly through the cylindrical mold by the discharge force of the extruder etc. After that, cutting at relatively high temperature into a block (in the form of a block) or rolling two rolls at relatively high temperature (for example, Kansai Roll Co., Ltd. product name: 8 X 20) It is preferable to introduce the sheet into a box type roll machine) and make it into a sheet form.

Further, among the specific examples of the above-mentioned forming step, in order to obtain sufficient cooling, it may be extruded and formed into a sheet shape, a plate shape, a rod shape, a block shape or the like in the step (i). Is preferred. As a method of extruding, for example, an extruder, a polymer pump, a gear pump, etc. are attached to the outlet or outlet of the devolatilizer, and by further connecting an extruder, the mixture is extracted from the devolatilizer while the extruder is removed. Or the like may be adopted.

The extruder is not limited. For example, a single-screw extruder, a twin-screw extruder (for example, product name: SUPERTEX a II, manufactured by Japan Steel Works, Ltd .; product name: BT — 30 — S 2. Plastics Science Research Institute), SCR self-tallying type reactor (Mitsubishi Heavy Industries, Ltd.), KRC Nidor (Kurimoto Co., Ltd.), etc. are preferably mentioned. In order to extrude in the form of a sheet or plate of a fixed thickness, insert a T-die into the extruder and extrude it, or after it is taken out as a rod directly through a cylindrical mold by the exhaust force of the extruder itself, It is preferable to carry out a method such as loading into a rolling double roll (for example, Kansai Roll Co., Ltd. product name: 8 X 20 BOX type roll machine) in a relatively high temperature state. In addition, in order to extrude into granular form, it is preferable to install a drop former (product name: Roth foam, manufactured by Sandvik Co., Ltd.) in an extruder and extruding, etc. In order to discharge, it is preferable to carry out a method such as cutting in a relatively high temperature after taking it out as a rod directly through a cylindrical mold by the discharge force of the extruder itself.

In the case of extrusion with a constant thickness, the thickness is generally in the range of 0.5 to 4 in consideration of the cooling efficiency in the subsequent cooling / solidifying step and the size when finally obtained by granulation. It is preferable to use a cold air to cool the extruded and formed mixture so as not to break the formed shape, which is preferably 1 mm, more preferably 1 to 3 mm, and still more preferably 1.5 to 2.5 mm. It is preferable to cool using such as.

In the production method of the present invention, the step (kneading step) of adding various stabilizers and the like to the mixture and kneading is performed before the cooling / solidifying step (or in the case of performing the above forming step beforehand). May be included. ,

Examples of the stabilizer include, but are not limited to, heat stabilizers, light stabilizers, ultraviolet light absorbers, antioxidants (antioxidants), preservatives, light resistance improvers, plasticizers (diocyl phthalate, Small molecule Amount of polyether compound etc.), filler (such as strong carbon), surfactant (such as ethylene oxide non-ionic surfactant), lubricant (such as calcium stearate), etc. i) Stabilizers added prior to the degassing step as required in the production method of the present invention, which have been reduced and removed while degassing, (ii) in the production method of the present invention Stabilizers, which were scheduled to be added after the degassing step as necessary, are preferred.

In the kneading step, various additives may be added / kneaded as necessary, in addition to the above-mentioned stabilizers. For example, organic or inorganic fine particles, low molecular weight compounds (having a boiling point of 300 ° C. or less) Low molecular weight compounds (solvents) are preferred. Among them, organic or inorganic fine particles can exhibit functions such as blocking prevention depending on the use purpose and use form of the positive electrode material composition. As the organic fine particles, for example, fine particles of polystyrene, polyethylene and polypropylene are preferable, and as the inorganic fine particles, for example, fine particles of silica, alumina and zirconia or their composite oxides are preferable.

The kneading apparatus which can be used in the kneading step is not limited, but, for example, those exemplified as the mixing apparatus which can be used in the step (I) for the mixing and the step (I I) are preferable. When the kneading step is performed after the volatilization step, it is preferable that the kneader be connected from the volatilization device via a polymer pump, a gear pump or the like.

In the case of performing the above-mentioned forming step after the kneading step, a polymer pump, a gear pump, etc. may be attached to the outlet or outlet of the kneading device, and it may be further connected to an extruder or the like.

Granulation step

The granulation step is to granulate (eg, pelletize) the mixture (preferably, the mixture obtained after the cooling and solidification step).

The apparatus that can be used in the granulation step is not limited, but, for example, a sheet pelletizer (for example, Holly Co., Ltd., product name: sheet pelletizer SG (E)-220), a classifier (for example, Holly Corporation) Product name: U-480 type), Strand cutter (manufactured by Isuzu Chemical Engineering Co., Ltd., Product name: SFC-1 0 0), and the like. Among them, a sheet pelletizer is preferred in that the particle size of the obtained granular material is easy to be uniform. The sheet pelletizer is not limited, but, for example, when cutting a material having a low pour point or cutting an adhesive material, the cutter portion, in particular, the slitter roll portion is cooled with a refrigerant. Those having a function capable of cooling the resin with cold air in those parts are preferable. The temperature of this cooling is not limited, and it is preferable that the mixture to be granulated (in particular, the polymer ^) be a crystallization temperature and / or a temperature that can be a temperature below the melting point, for example, _ 2 5 It is preferable that the temperature is -40 ° C, more preferably one 20 to 30 ° C, and still more preferably one 15 to 25 ° C.

In the production method of the present invention, after the granulation step or before the granulation step (that is, between the cooling and solidification step and the granulation step, and before the cooling and solidification step), various mixtures such as a stabilizer and the like can be used. It may include a step of adding an additive (eg, dust etc.). Examples of the additive include, but are not limited to, heat stabilizers, light stabilizers, ultraviolet light absorbers, antioxidants, preservatives, light resistance improvers, plasticizers, various fillers, surfactants, lubricants, solid substances, etc. An anti-caking agent, a flowability improver, etc. may be mentioned, but among them, an anti-caking agent, a flowability improvement agent (for example, a product manufactured by Nippon Aerosil Co., Name: aerosil R 9 72 2, aerosil R 9 7 4) are preferred. As a method of adding various additives, a table feeder or the like may be used to supply and dust the particulate mixture of the mixture on the vibrator, or may be provided to supply the mixture prior to the granulation step and the like. The method is mentioned.

In the production method of the present invention, a step of selecting particles having a desired particle diameter from the mixture after granulation, removing large particles generated in the granulation step and the drying step ) May be provided. In this sorting step, classification may be carried out using a generally known sieve, but in consideration of productivity, for example, the particles are flowed on a sieve of a metal inclined surface having irregularities while being vibrated. Sorting, vibrating the metal plate with holes in the horizontal direction for sorting, or the sieve itself is a trumpet-like and horizontal type, and the inclined surface of the sieve is rotated so that the particles rotate. And the like are preferable. Examples of devices that can be used in the sorting step include various known devices that allow sorting of particles, such as a vibrating screen (manufactured by Seishin Enterprise Co., Ltd., product name: Rotex 1302 PSSSSL type). It can be mentioned. It is preferable that the sorting of the particles be performed by direct derivation to the sieve as described above. Before the sorting step, for example, any additive added to the mixture which is not sufficiently attached to the composition is subjected to vibration (horizontal direction or vertical direction), scraper, brush, etc. It may be equipped with a process of removing it by an external force, such as bringing it into contact and peeling it off or flying it with wind power. The sorting step may be performed after the drying step described later.

[Drying process, humidity control process]

The drying step is to dry the mixture (preferably, the mixture obtained after the granulation step). The drying step is a step of actively reducing the water content in the mixture, and differs from the moisture absorption preventing treatment described later in this point. In addition, this drying step is particularly effective, for example, when an atmosphere using water (water for metal plate cooling) is directly present during the manufacturing step of the present invention (in particular, in the above-mentioned cooling / solidifying step). It is a process. If the mixture is treated under such an atmosphere of water, the water content will increase significantly more than usual.

The drying method in the drying step is not limited. For example, (i) a mixture is injected into the mouth of a mixture, and then compressed air is blown from the top and bottom to circulate and dry; (ii) the mixture is a conical dryer It is preferable to use a method of ventilating compressed air after drying, or (iii) a method of charging the mixture into a ventilated rotary dryer (eg, a rotary kiln etc.) and ventilating compressed air for drying. The drying method may be performed alone or in combination of two or more.

In the drying step, the water content of the mixture can be reduced to a desired range by appropriately selecting and setting the various drying methods described above, the drying temperature, the drying time, etc. Specifically, the desired range to be described later It is preferable to reduce to (specifically, 300 ppm or less). Even if the water content of the mixture already satisfies the desired range (specifically, 300 ppm or less) described later, the drying process can be performed even if it is not. Although the amount of water to be reduced in the drying step is not limited, it is preferable not to be too large in consideration of the cost and productivity of the drying process. Specifically, the reduction of the water content by the drying treatment is preferably 27 ppm or less, more preferably 7 ppm or less, and still more preferably 4,700 It is less than ppm. If the drying process exceeds this decrease range, the economy and productivity are inferior, and the polymer in the mixture is degraded, and finally the battery Performance may be adversely affected.

In the production method of the present invention, the above-mentioned drying step is not limited to the one performed on the mixture after the granulation step. For example, the above drying step is performed on the one after the cooling and solidification step. It can be performed between various processes or during various processes, and may be performed once or plural times in the whole manufacturing process.

The water content of the positive electrode material composition obtained by the production method of the present invention is preferably 300 ppm or less, more preferably 250 ppm or less, and still more preferably 200 ppm or less. . The water content referred to here may be achieved for the finally obtained positive electrode material composition, and needs to be achieved in the mixture in part or all of the production process in the production method of the present invention. Not that. If the water content exceeds 300 ppm, the water content and the lithium salt react and the lithium ion is consumed as a hydroxide, so that the ion conductivity decreases. For example, the battery performance of the lithium secondary battery There is a risk that

However, as described later, when the positive electrode material composition obtained by the production method of the present invention is introduced into an extruder or the like, melted and extruded, and used as a film-like positive electrode material, the positive electrode used in the extruder It is preferable that the water content of the material composition is relatively high because the film can be stably extruded by the plasticizing effect of the water. In such a case, a humidity control process is provided after the granulation process to adjust the humidity of the positive electrode material composition, and then, for example, a vent that can be drawn by pressure reduction is provided at the tip of an extruder etc. Water may be removed immediately before the outlet, etc., and water may be removed immediately before film formation with an extruder or the like to make the water content in the above-mentioned range (300 ppm or less). In addition, even when humidity control is performed in the humidity control process, the water content of the positive electrode material composition after humidity control is less than 30,000 ppm, in consideration of the amount of water that can be removed immediately before film formation. It is preferable to

The method of controlling humidity in the humidity control step is not limited. For example, after a predetermined amount of water (preferably ion-exchanged water) is sprayed to the positive electrode material composition through a spray or spray nozzle etc. The positive electrode material composition and the sprayed water may be adapted to each other by stirring or rotating using the above apparatus.

In the production method of the present invention, a step of preventing moisture absorption of the mixture (hygroscopicity preventing step) may be provided. In this step, the mixture is subjected to a treatment capable of reducing the amount of water taken from the production atmosphere, but it is not always necessary to completely suppress the increase in the amount of water contained in the treatment process. The increase in water content should be suppressed as compared to the case where such treatment is not performed. Hereinafter, the moisture absorption preventing step will be described in detail.

Moisture absorption prevention process

The moisture absorption preventing step can be performed instead of the drying step because the same effect as the drying step can be obtained in terms of controlling and managing the water content of the mixture. May be performed. The moisture absorption preventing step can be performed between various steps in the manufacturing method of the present invention or during various steps, and may be performed once or plural times in the whole manufacturing process, and is not limited.

Examples of the treatment in the moisture absorption preventing step include so-called film-type dehumidifying treatment, freezing-type dehumidifying treatment, and adsorbent-type dehumidifying treatment. Specifically, the membrane-type dehumidifying process covers a desired region in a region including various devices / equipment used in the manufacturing method of the present invention, equipment, and a movement path of the mixture with a highly airtight material. Dry air obtained by absorbing moisture in compressed air (saturated air with a relative humidity of 100%) into the hollow fiber membrane is sent by a compressor to create a dry atmosphere. This treatment can be performed, for example, using a hollow fiber membrane separation type compressed air dryer (manufactured by Toshiba Plant Construction Co., Ltd., product name: MA CDASS). The compressed air is preferably at a dew point of 10 ° C. or less, more preferably at a dew point of 20 ° C. or less, still more preferably at a dew point of 30 ° C. or less. If the compressed air exceeds the dew point −10, the water content of the mixture increases, which may cause a decrease in battery performance and the like. In addition to the dry air described above, an inert gas such as nitrogen can also be used.

Specifically, the freezing and dehumidifying treatment is a treatment that cools compressed air with a refrigerator, condenses and discharges moisture in the compressed air to obtain dry air, and creates a dry atmosphere.

The adsorbent-type dehumidifying treatment is, specifically, a treatment in which moisture is adsorbed by an adsorbent such as activated alumina to obtain dry air, thereby creating a dry atmosphere.

In the moisture absorption preventing step, the increase range of the moisture content of the mixture during the moisture absorption preventing treatment is preferably 250 ppm or less, more preferably 200 ppm or less, and still more preferably 15 It is less than 0 ppm. If the above increase exceeds 250 ppm, the water content of the mixture increases, which may cause a decrease in battery performance and the like. Further, when the moisture content of the mixture is within the desired range described later at the time of performing the moisture absorption preventing process, it is preferable to maintain the range after the process.

The positive electrode material composition (ie, the mixture finally obtained) obtained by the production method of the present invention may be introduced into an extruder or the like, melted and extruded, and used as a film-like positive electrode material. At that time, the equipment to be supplied to the extruder may be appropriately selected and adopted according to the shape of the positive electrode material composition for the introduction into the extruder. For example, when the shape of the composition is in the form of particles, it can be quantitatively supplied from the belt type feeder 1 to the first supply port on the motor 1 side of the extruder, in particular when it is in the form of pellets. It can be supplied quantitatively from a single screw or single screw type screw-up feeder. When the composition is in the form of a block (in the form of a block), a hopper disk charger type one, a kneader one, etc. Melta one (manufactured by Moriyama Co., Ltd.) using a uniaxial or biaxial system or a combination of both systems. Product name: 2 TR-50 or 2 TR-75) can be melted and supplied quantitatively to the first supply port on the motor side of the extruder. Further, the positive electrode material composition may be a mixture obtained after step (II) (in this case, the polymer itself in the molten state is used as a medium in step (I)) or the solvent obtained after step (III) It is also possible to quantitatively feed the first feed port of the extruder in the molten state and without shape, as in the case of a mixture which contains no or almost nothing.

In the production method of the present invention, it is preferable to perform at least one of the various production steps described above in an inert gas atmosphere. By performing the reaction under an inert gas atmosphere, decomposition of the polymer in the mixture can be suppressed, and an effect of suppressing moisture absorption can be obtained. Preferably, the inert gas atmosphere is a gas atmosphere containing at least 99% by volume of an inert gas. Examples of the inert gas include nitrogen, argon and helium. The gas containing the above-mentioned inert gas can be used to reduce the water content of the positive electrode material composition. It is preferable to use a low water content to keep it low (eg, 300 ppm or less, preferably 250 ppm or less, more preferably 200 ppm or less).

The method of performing the desired step under an inert gas atmosphere is not limited, but, for example, in the membrane-type dehumidifying treatment in the moisture absorption preventing step described above, a gas containing the above-mentioned inert gas is used instead of dry air. The method used is preferably applicable.

In the production method of the present invention, the weight average molecular weight of the polymer used in the step (I) (here, the polymer before mixing) is Mw. When the weight average molecular weight of the polymer in the mixture after the final step is Mw, it is preferable that the weight average molecular weight reduction rate (D _Mw ) determined by the following formula (1) is 10% or less. According to the production method of the present invention as described above, the reduction rate of the weight average molecular weight of the polymer can be easily set within the above range.

D _Mw (%) = [(Mw. 1 Mw) / Mw ₀ ] XI 00 (1)

The D _Mw is more preferably 7% or less, and still more preferably 5% or less. When the D _Mw exceeds 10%, there is a possibility that the battery performance may be lowered, and there is also a possibility that the positive electrode material composition can not exhibit stable battery performance. The above-mentioned final step means the final step among all the steps carried out after step (I) and step (II) for mixing.

As described above, the positive electrode material composition obtained by the production method of the present invention is suitable as a material composition that can be used for the positive electrode portion of a lithium secondary battery. Example

EXAMPLES The present invention will be more specifically described below by Examples and Comparative Examples, but the present invention is not limited thereto. In the following, for convenience, “parts by weight” may be described simply as “parts” and “liters” may be simply described as “L”. Also, "wt%" may be described as "wt%". The measurement method and evaluation method in Examples and Comparative Examples will be described below.

Measurement of weight average molecular weight (Mw) and degree of polydispersity (molecular weight distribution) (Mw / Mn)>

It measured by the GPC apparatus (The Tosoh company make, product name: I LC-8120GPC) which prepared the calibration curve using the standard molecular weight sample of polyethylene oxide.

The polymer in the polymer solution was dissolved by adding acetonitrile to the polymer solution so that the concentration of the polymer in the polymer solution was 1 wt%, and centrifuged at 2000 ppm for 3 minutes. The supernatant was added with a predetermined solvent (eluent (acetonitrile water Z anhydrous sodium acetate)) to dilute, and then measured.

As for the polymer in the positive electrode material composition (or mixture), an acetonitrile is added to the composition (or mixture) to make a 1 wt% solution of the composition (or mixture), and the solution is a Tatchich mixer. Stir well with a shaker to disperse the electrode active material and dissolve the polymer. Thereafter, the mixture was filtered through a filter (non-aqueous, opening: 45 / zm) to remove insolubles, and the filtrate was diluted with the above-mentioned eluent and then measured.

10 wt% of dehydrated acetonitrile (Molecular sieve (manufactured by UNION SHOWA, product name: type 4A, 1, 6) is added to the positive electrode material composition (or mixture), and the water content becomes 25 ppm or less (As dewatered) to add 5 to 3 of the composition (or mixture) The solution is adjusted to a 0 wt% solution, and the solution is stirred with a strong stirrer to sufficiently disperse the electrode active material and dissolve the polymer. After that, the mixture is centrifuged to precipitate the main insoluble matter, and the supernatant is sampled with a syringe for about 2 to 3 mL, and Karl Fischer moisture measuring instrument (Coulometric titration method, manufactured by Hiranuma Sangyo Co., Ltd., Product name: AQ-7) The water content (p pm) in the solution was measured (Measurement A) using. Separately, with regard to dehydrated acetonitrile used as a solvent, the water content (p pm) was measured (measurement B) using the same measuring instrument. From the water content according to measurement A, the water content according to measurement B was subtracted to obtain the water content (ppm) in the composition (or mixture).

A polymer solution or a composition (or mixture) solution in which acetonitrile is added and dissolved for a positive electrode material composition (or mixture) is weighed in a predetermined amount, and placed in a dryer, 110 ° C., 0.09 ~ 0. 1 OMP a for 20 minutes under vacuum heating. The weight after heating under reduced pressure was weighed, and the solid content (wt%) of the polymer solution or the composition (or mixture) solution was determined as the weight of the non-volatile component.

Ascetonitrile was added to the positive electrode material composition (or mixture) to make a 10 wt% solution of the composition (or mixture). This solution was filtered under reduced pressure with a membrane filter, and after that, acetonitrile was poured onto the filter to wash the filtrate and filtered under reduced pressure (in this case, the total concentration of polymer and electrolyte salt compound in the filtrate was about 1 Wash with an amount of wt% acetonitrile. The composition (or mixture) is obtained from the intensity of Li measured by I CP -AES (Inductively coupled plasma emission spectrometry, manufactured by Seiko Instruments Inc., product name: SPS 4000) using the obtained filtrate as a sample The concentration of the electrolyte salt compound in the solution is calculated, and the content ratio of the electrolyte salt compound in the composition (or mixture) in consideration of the concentration of the composition (or mixture) in the solution (wt% I asked for).

It measured by either method of following (A) or (B).

(A) To a positive electrode material composition (or a mixture), add acetonitrile to make a 7 to 1 wt% solution of the composition (or a mixture), stir the solution with a stirrer, and then centrifuge it. The separation treatment is carried out to precipitate insolubles, and only the supernatant is vacuum filtered using a membrane filter. Separately, for precipitated insoluble matter, add acetonitrile again, stir with a stirrer, and filter under reduced pressure with a membrane filter in the same manner.

The residue obtained by the above two vacuum filtrations (the residue remaining on the filter) is dried at 110 ° C. under a vacuum heating of 0.0.09-0. 1 OMP a for 1 hour, and the total weight after drying The weight of the electrode active material containing the conductive aid was measured. From the weight and the weight of the positive electrode material composition (or mixture) used in the measurement, the content ratio (wt%) of the electrode active material containing the conductive auxiliary in the composition (or mixture) is determined. The

About the filtrate obtained by the said 2 times vacuum filtration, the sum total of the polymer and electrolyte chloride in the positive electrode material composition used for measurement as solid content by applying the measurement method of solid content mentioned above By determining the content ratio (wt%) and subtracting the content ratio (wt%) of the electrolyte salt compound determined by the above-mentioned method from the total content ratio, the content of the polymer alone can be reduced. The combination (W t%) was determined.

(B) A positive electrode material composition (or mixture) is formed into a sheet having a thickness of 2 mm, and a circular sample having a diameter of 3 cm cut out from the sheet is measured by a fluorescent X-ray analyzer (PW-240 4 manufactured by PHILIPS, INC. Measure the strength of vanadium in the electrode active material. Then, the content ratio (wt%) of the electrode active material is calculated in advance from a calibration curve prepared for a sample of which the content of the electrode active material is known. Evaluation of dispersion after mixing

The slurry-like mixture in the stirring apparatus after the mixing step is sampled, and the degree to which the particulate matter can be visually confirmed in the sample is shown in Table 1 below as one element of evaluation of the dispersion state after mixing. Evaluated by criteria.

Separately, from the slurry-like mixture in the stirring device, several places (2 to 3 locations from the jacket side and the central part (near the stirring rod) in the stirring device etc.) are sampled, and electrolyte for each sample by the above-mentioned method The content ratio of the salt compound and the content ratio of the electrode active material containing the conductive aid were measured. Regarding the fluctuation of each measured value among each sample, paying attention to the maximum difference of each measured value among each sample, it is evaluated according to the criteria shown in Table 1 below as one factor of evaluation of the dispersion state after mixing. did.

【table 1】

Into a glass container, 50 parts of crotch form is previously charged, and into this, a mixture of slurry is refined and charged in an amount corresponding to 3 to 4 parts in solid content (this weight is X (g), The amount of solid content contained in the slurry-like mixture of X (g) is represented by X (g)), and then 80 parts of chloroform was further added. Then attach a cooling pipe to the glass container, heat at 55 ° C for 2 hours to dissolve the slurry-like mixture, cool, and let the contents of the glass container be made of metal mesh (made of SUS 316, wire diameter The sample was poured on top of 0. 06, 150 m / s, opening 0. 109 mm), and the glass container was washed and the residue on the metal mesh was washed with a small amount of flask. The residue on the metal mesh was dried at room temperature overnight under reduced pressure to remove volatile components, and then the weight of the obtained residue was refined (this weight is referred to as y (g)). And the value calculated | required by (yZX) X I 00 was made into aggregate content rate (%).

[Example 1]

<< Preparation of Polymer Solution >>

Max Blend Wing (Sumitomo Heavy Industries, Ltd.) and 1 L reactor equipped with an addition port The solvent (toluene) was charged with 170 parts and stirred at 70 ° C. for 3 hours to wash the inside of the reactor, and then the solvent was removed and dried by heating, and then the inside of the reactor was flushed with nitrogen. A 3-substitution operation (0.5MP a) was performed and nitrogen substitution was performed. In this reactor, 1 part of toluene (water content: not more than 20 ppm) 94 dewatered with molecular sieve and t-butoxide potassium as a reaction initiator (20 wt% tetrahydrofuran solution) 1. 7 9 We put in department and sequentially. After the introduction, the maxblend blade is rotated at 90 rpm and the reactor is purged with nitrogen while stirring, and pressurized with nitrogen until the pressure in the reactor becomes 0.3MPa, and warm water is added to the jacket The temperature rose.

After confirming that the internal temperature of the reactor had reached 90 ° C., the ethylene oxide feed was started at a feed rate of 220.2 parts and was fed quantitatively for 40 minutes. Twenty minutes after the start of ethylene oxide supply, the supply of butylene oxide denatured by molecular sieve (water content: 400 ppm or less) was started at a supply rate of 48.9 parts Zh for 20 minutes quantitatively. Supplied. Forty minutes after the start of ethylene oxide supply, the solution was supplied quantitatively for 1 hour each at a supply rate of 14.46 parts Zh for ethylene oxide and 36. 6 parts for butylene oxide. One hour and 40 minutes after the supply start of ethylene oxide, 100 parts / h for ethylene oxide and 24.48 parts for butylene oxide, respectively, supply is continued for an additional one hour and 20 minutes, respectively. did. Three hours after the start of ethylene oxide supply, it was quantitatively supplied for another two hours at a supply rate of 73.2 parts of ethylene oxide. Five hours after the start of the supply of ethylene oxide, ethylene oxide was supplied quantitatively at a supply rate of 58.8 parts Zh for 2.5 hours (supply amount of ethylene oxide: total 7 3 parts of ethylene oxide, Supply of butylene oxide: Total 8 1. 4). The reaction was carried out at 100 ° C ± 5 ° C while monitoring and controlling internal temperature rise and internal pressure rise due to heat of polymerization during supply.

After the end of the feeding, it was aged by further holding at 100 ° C. ± 5 ° C. for 2 hours.

By the above operation, a polymer solution (10) having a weight-average molecular weight Mw of 12.4 000 and a solid content of 45.8 w t% was obtained.

<< Mixing process >>

(Mixture of polymer solution and Li salt)

The water content in the unit under nitrogen flow, with the vertical mixing agitator equipped with Max Blend wings (product name: Max Prand Wing, manufactured by Sumitomo Heavy Industries, Ltd.), preheated at 150 ° C and flowing nitrogen except, substituted by nitrogen (1 to 5 k gZcm pressurized with 0. 5 k gZcm ² up ² Kai圧) performed 4 times, it was raised jacket temperature to 70 ° C.

The polymer solution (10) 3 3. 30 parts which had been preheated and kept at about 80 ° C. was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ).

Further, 3.28 parts of L i salt previously purged with nitrogen were fed from the hopper to the stirring device with the vent opened. Thereafter, the hopper and the like are washed with 6,000 parts of toluene, and after washing, the stirrer is operated (Max blend wing: 90 rpm) and the internal temperature is 70.2. C (jacket temperature: 71 ° C.) and stirred for 2 hours.

(Mixed with electrode active material containing conductive aid)

In a vertical twin screw system (product name: Super Blend, manufactured by Sumitomo Heavy Industries, Ltd.) equipped with a super blend wing (inner wing: max blend wing, outer wing: spiral deformation baffle) While flowing a small amount of nitrogen, add antioxidant (O.I.I.P., product name: Yoshinox BB) 0. 076 parts into the observation window, charge 30 parts of toluene, and further, add carbon as a conductive aid From the hopper, 31. 68 parts of an electrode active material containing 1 to 8 wt% of black (US AVE STOR LLC, product name: lithiated vanadium oxide carbon blend) was charged. Thereafter, the hopper and the like were washed with 10.0 parts of toluene, and the inlet was closed. After the washing, the stirrer was operated (inner blade: 75 rpm, outer blade: 29 rpm), and mixed for 30 minutes with stirring to obtain a slurry. After completion of the stirring, the degassing operation of pressurizing the inside of the stirring apparatus to 1.6 kgzcm ² with nitrogen and reducing the pressure to 10 O mmHg was repeated several times to remove excess water and dissolved oxygen in the system.

From 42.58 parts of the mixture of the polymer solution and Li salt described above, from the vertical concentric stirring device equipped with the Max Blend wing, to the vertical twin screw agitation type with the Spearper Blend wing mounted A nitrogen pressure of 1.0 _kg / cm ² and a pipe temperature of about 100 were introduced through a pipe connected to both stirrers. After that, operate the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), adjust the internal temperature to 50.5 ° C (jacket temperature: 58.0 ° C) under normal pressure, and mix for 2 hours with stirring And I got a gallery.

Thus, a slurry-like mixture (11) was obtained.

The mixture (11) had a solid content of 42.8 wt%, a polymer weight average molecular weight Mw of 123,000, and a content ratio of the electrode active material containing a conductive additive of 64. 6 wt% The evaluation of the dispersion state after mixing was “◎”.

Vacuum degassing process

(Pre-volatilization)

In the above-mentioned stirring apparatus containing a mixture (11) (a vertical concentric biaxial stirring apparatus equipped with a super blend blade), an antioxidant (manufactured by AP Corporation, product name: Yoshinocks BB) 0. 057 After the parts were put in from the observation window, the observation window was closed, connected to a pressure reduction line equipped with a vacuum pump, and cold water at 10 ° C. was passed through the condenser. After that, while operating the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), the vacuum pump is also operated and the inside of the stirring device is gradually reduced to 70 Torr, and the internal temperature is 50 ° C (jacket Temperature: Approximately 81 ° C), then control is performed so that the internal temperature is 47 to 50 ° C (jacket temperature: 79 to 81), and the degree of pressure reduction is in the range of 62 to 70 Torr, and stay in the holder tank. Operation was carried out while checking the volume or weight of toluene discharged (target solid content: 70 wt%). After the operation, the inside of the stirrer was depressurized with nitrogen to a slight pressure of 1.0 kg / cm ² . Thus, a mixture (12) was obtained.

The mixture (12) had a solid content of 71. O t t%, a polymer weight average molecular weight Mw of 122,000, and a content ratio of the electrode active material containing a conductive additive of 66.6 wt%

(This degassing)

The main body, supply line and outlet line of KRC kneader (manufactured by Kurimoto Soken Co., Ltd.) are replaced with nitrogen, and the temperature is raised to 70 ° C. while circulating the heat medium of the jacket, and After steaming and warming the traces, the KRC KNIDAI's screen was operated at 38 rpm. After that, operate the above-mentioned stirring device containing the mixture (12) (inner blade: stop, outer blade: 10 rpm), open the flush valve connected to the bottom of the stirring device, and After the mixture (12) is supplied to the KRC kneader and it is confirmed that the mixture (12) is discharged from the outlet of the KRC aider, the vacuum pump is operated to reduce the pressure in the KRC damper. The pressure was reduced to 25 OT orr. After confirming that the distillation of toluene was sufficiently stabilized, the degree of pressure reduction was further increased, and the degree of pressure was 12 OTo rr, and the internal temperature was 68.9 ° C. (jacket temperature : 7 0. 0 ° C), from a single tube (diameter: 48 mm) at the outlet of the KRC kneader, a mixture of rods (cylindrical, diameter: 48 mm, length: 300 mm) under nitrogen stream (13) ) Got.

The mixture (13) had a solid content of 95.6 wt%, a polymer weight average molecular weight Mw of 120,000, and a content ratio of the electrode active material containing a conductive auxiliary was 65.6 wt% Met

<< Cooling and Solidification Process >>

The mixture (13) obtained after the volatilization was put in an aluminum laminate bag, sufficiently purged with nitrogen, sealed with a heat seal, and placed in a freezer at ― 10 to -5 ° C to cool overnight.

Granulation process

While cooling the mixture (13) after cooling to below 15 ° C with a spot cooler, it is supplied to a powder mill (manufactured by Holley, product name: U-480 type) at a supply rate of 0.55 kg / min. It was crushed.

The ground product of the obtained mixture (1 3), passing through a mesh with an opening of 1. 00 to 3. 34 mm occupies 80% or more of the whole on a number basis, and the water content is 2065 ppm. The solid content was 96.0 wt%, and the weight average molecular weight of the polymer Mw was 12.6 thousand.

<< Drying process >>

The inside of the conical dryer (Nikko Industry Co., Ltd. product name: vacuum tumble dryer) used as a dryer is sufficiently replaced with nitrogen or compressed air (dry air) in advance, and the jacket The heat medium was heated to 20 ° C. and the inside of the dryer was heated to 19 ° C.

Into this dryer, 38.0 kg of the powder of the mixture (1 3) was put from the inlet of the dryer, and tightly closed with a bolt.

Next, the valve was checked for opening and closing, and the inside of the dryer was depressurized with a vacuum pump. After confirming that the degree of pressure reduction was 6 Torr or less (798 Pa) or less and that there were no leaks, nitrogen was circulated in the dryer at 5 LZ min. In this state (that is, in a state where the internal temperature is 20, the nitrogen flow S LZmin and the degree of reduced pressure 6 Torr or less (798 P a) or less), the powder is held for 12 hours or longer to dry the powder.

The pulverized product (the positive electrode material composition of the present invention) of the mixture (13) obtained by the drying treatment as described above has a water content of 170 ppm and a solid content of 100 wt%. Weight average molecular weight Mw is 12.6 000, polymer molecular weight distribution (MwZMn) is 1.40, the content ratio of Li salt is 6. 8 wt%, and electrode active material containing a conductive aid The content rate of the substance was 65.6 wt%.

[Example 2]

<< Preparation of polymer solution >>

In the same manner as in Example 1, a polymer solution (10) was obtained in which the weight average molecular weight Mw of the polymer is 120,000 and the solid content is 45.8 wt%. << Mixing process >>

(Mixture of polymer solution and Li salt)

Remove the moisture in the unit under nitrogen flow beforehand by heating at 150 in a box-shaped concentric stirring device (product name: Max Blend wing, manufactured by Sumitomo Heavy Industries, Ltd.) equipped with Max Blend wings. , purged with nitrogen (1 to 5 k gZcm pressurized with 0. 5 k gZcm ² up ² Kai圧) performed 4 times, was raised jacket temperature to 70 ° C.

33. 30 parts of the polymer solution (10), which had been preheated to about 8 and heated, was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ).

Further, 3.28 parts of L i salt previously purged with nitrogen were fed from the hopper to the stirring device with the vent opened. After that, the hopper etc. are washed with toluene 6.00 parts, and after washing, the agitator is operated (Max blend wing: 90 rpm) and the internal temperature is 70.2 ° C. (jacket temperature: 71 ° C.) The mixture was stirred and mixed for 2 hours.

(Mixed with electrode active material containing conductive aid)

A small amount of nitrogen is contained in a vertical twin screw system (product name: Super Blend, manufactured by Sumitomo Heavy Industries, Ltd.) equipped with a super blend wing (inner wing: max blend wing, outer wing: spiral deformation puffle). While flowing, add 0. 076 parts of an antioxidant (manufactured by AP corporation, product name: Yoshinox BB) from the viewing window, then charge 30 parts of toluene, and further add carbon black as a conductive aid. From the hopper, 31. 68 parts of an electrode active material (US AVE STOR L LC, product name: lithium vanadium oxide Z carbon blend) containing ̃8 wt% was charged. Thereafter, the hopper and the like were washed with 10.0 parts of toluene, and the inlet was closed. After the washing, the stirrer was operated (inner blade: 75 rpm, outer blade: 29 rpm), and mixed for 30 minutes with stirring to obtain a slurry. Except After stirring, stirring in the apparatus 1. several times de揮操operation to vacuum up to 6 k § / ^/ Ji ² pressed 1 0 OmmHg by nitrogen, excess moisture Oyo. Beauty dissolved oxygen in the system The

42. 58 parts of the mixture of 'polymer solution and Li salt described above, from a paddle type concentric stirring device equipped with the Max Blend wing, to a boat type concentric biaxial stirring device loaded with the Superprendo blade, From a pipe connected to both stirrers, a nitrogen pressure of 1.0 kgzcm ² and a pipe temperature of about 100 ° C. were introduced. After that, operate the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), adjust the internal temperature to 50. 5 (jacket temperature: 50. 8 ° C) under normal pressure, stir and mix for 2 hours, I got a gallery.

Thus, a slurry-like mixture (21) was obtained.

The mixture (21) has a solid content of 52.1%, a polymer weight average molecular weight Mw of 123,000, and a content ratio of the electrode active material containing a conductive additive of 64. 6%, The evaluation of the dispersion state later was “◎”, and the aggregate content rate after mixing was 12.9%.

<< Degassing process >>

Turn on heater 1 of a 30 mm φ twin-screw extruder (made by Plastic Engineering Laboratory, product name: BT-30-S 2) and set the temperature to 100 ° C for the 1st, 2nd and 3rd vents. Heat the vent, fifth vent, head die to 90 ° C.

The inside of the stirring device containing the slurry-like mixture (21) in the above mixing step is pressurized with nitrogen to 0.05MPa, and a gear pump installed between the stirring device and the first vent of the twin screw extruder. After filling the mixture (21) until just before the first vent, rotate the 2nd shaft at low speed, start supplying the mixture (21), and increase the rotation speed of the 2nd shaft to 100 r pm It was confirmed that the mixture (21) came out from the twin die. After that, start the vacuum pump and decompress the second vent to 349 Torr and the third vent to 69 Torr, and discharge it from the biaxial die with a rod volume of 6 kgzh (cylindrical, diameter: 25 mm A mixture of (23) was obtained.

The mixture (23) has a solid content of 98.6 wt%, a polymer weight average molecular weight Mw of 12,000, and a content ratio of the electrode active material containing a conductive additive is 64.6 wt% The

<< Cooling and Solidification Process >>

.The mixture (23) obtained after this volatilization is kept at about 90, and a rolled double roll (Kansai Roll Co., Ltd., product name: 8 X 20 BOX type roll, temperature of front roll: 1 1 3 ° C, temperature of back roll: 1 1. 4 and guide width: 55 mm, rotation speed: 0.5 rpm), thickness 2.0 mm, width 76.5 mm, length about 10 m I made a sheet.

The sheeted mixture (23) was placed in an aluminum laminate bag, thoroughly purged with nitrogen, sealed with a heat seal, and allowed to cool at room temperature overnight. , << Granulation process >>

The obtained sheet is cooled to 15 ° C or less with a spot cooler, and the temperature is supplied to a sheet cutter (manufactured by Horai Co., Ltd., product name: SGE-220) at a temperature of 9 ° C. The mixture was charged at k gZ min, and was cut at a vertical blade rotational speed of 59. 2 Hz and a horizontal blade rotational speed of 100. OHz to obtain a square pellet-like mixture.

The resulting angular pellet-like mixture had a thickness of 1.8 mm and a width of 4. O mm, and a length of 70% or more of the whole on the number basis satisfied a range of 3.7 ± 0.5 mm. The average weight of one tablet was 41. Omg, the water content was 2050 ppm, the solid content was 99.0 wt%, and the weight average molecular weight Mw of the polymer was 121,000.

<< Drying process >>

The inside of the conical dryer (Nikko Industry Co., Ltd. product name: vacuum-type tumble dryer) used as a dryer is sufficiently placed in advance with nitrogen or compressed air (dry air), and the jacket is heated further. The medium was heated to 20 ° C. and the inside of the dryer was heated to 19 ° C.

Into this dryer, 38.0 kg of the mixture in the form of a square pellet was placed from the inlet of the dryer, and tightly tightened with a bolt.

Next, the valve was checked for opening and closing, and the inside of the dryer was depressurized with a vacuum pump. After confirming that the degree of pressure reduction was 6 Torr or less (798 Pa) or less and that there were no leaks, nitrogen was circulated in the dryer at 5 LZ min. In this state (that is, the state with an internal temperature of 20 ° C., a nitrogen flow S LZmin and a pressure reduction degree of 6 Torr or less (798 P a) or less), the angular pellet was dried for 12 hours or longer. .

The rectangular pellet-like mixture (positive electrode material composition of the present invention) obtained by the drying treatment as described above has a water content of 150 ppm and a solid content of 100 wt%, and the weight average of the polymer The molecular weight Mw is 120,000, the molecular weight distribution (MwZMn) of the polymer I is 1.45, the content ratio of Li salt is 6. 8 wt%, and the electrode active material containing a conductive aid Containing percentage The match was 65.6 wt%.

[Example 3]

<< Preparation of polymer solution >>

In the same manner as in Example 1, a polymer solution (10) was obtained in which the weight average molecular weight Mw of the polymer is 124,000 and the solid content is 45.8 wt%.

<< Mixing process >>

(Mixture of polymer solution and Li salt)

In the same manner as in Example 1, mixing of the polymer solution and the Li salt, and mixing with the electrode active material containing the conductive aid, the solid content is 42.8 wt%, and the weight average molecular weight of the polymer Thus, a slurry-like mixture (31) was obtained, in which the Mw was 123,000 and the content ratio of the electrode active material containing the conductive additive was 64.6%.

<< Degassing process >>

(Pre-volatilization)

Mixture (31) was added to the above-mentioned stirring apparatus (a vertical twin screw stirring apparatus equipped with a super blend blade), an antioxidant (manufactured by AP Corporation, product name: Yoshinocks BB) 0. 057 After the parts were put in from the observation window, the observation window was closed, connected to a pressure reduction line equipped with a vacuum pump, and cold water at 10 ° C. was passed through the condenser. After that, while operating the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), the vacuum pump is also operated and the pressure in the stirring device is gradually reduced to 70 Torr, and the internal temperature is 50 ° C ( After the jacket temperature is about 81 ° C, the internal temperature is 47 to 50 ° C (jacket temperature: 79 to 81 ° C), and the degree of pressure reduction is controlled to be in the range of 62 to 70 Torr. Operation was performed while checking the volume or weight of toluene distilled inside (target solid content: 70 wt%). After the operation, the inside of the stirring apparatus was depressurized with nitrogen to a slight pressure of 1.0 kg · cm ² . Thus, a mixture (32) was obtained.

The mixture (32) had a solid content of 71. O t t%, a polymer weight-average molecular weight Mw of 122,000, and a content ratio of the electrode active material containing a conductive additive of 66.6 w t%

(This degassing)

The main body, supply line and outlet line of KRC kneader (manufactured by Kurimoto Soken Co., Ltd.) are replaced with nitrogen, and the temperature is raised to 70 ° C. while circulating the heat medium of the jacket, and After steam was flowed into the trace and warmed up, the KRC Kneader screw was operated at 38 rpm. After that, operate the above-mentioned stirring device containing the mixture (32) (inner blade: stop, outer blade: l Or pm), open the flush valve connected to the bottom of the stirring device, operate the Kier pump, The mixture (32) is supplied to the KRC kneader, and after confirming that the mixture (32) comes out from the outlet of the KRC kneader, the vacuum pump is operated to start reducing the pressure in the KRC kneader, and 25 OT orr The pressure was reduced until the distillation of toluene was confirmed to be sufficiently stable, and then the degree of pressure was increased to a pressure of 120 Torr and an internal temperature of 68.9 ° C. (jacket temperature: 70 ° C.). A mixture (33) of rod-like bodies (cylindrical, diameter: 48 mm, length: 300 mm) was obtained from a single tube (diameter: 50 mm) at the outlet of the KRC kneader under nitrogen stream.

The mixture (33) has a solid content of 95.6 wt%, a weight average molecular weight Mw of polymer composition of 126,000, and a content ratio of the electrode active material containing a conductive additive of 65.6 wt%. Ah It was

Granulation process

Apply a S-US wire directly along a single tube at the outlet of KRC kneader, and let the mixture (3 3) of rod-shaped bodies discharged at 80 to 90 ° C from the single tube have a length 2-3 It was cut into 0 cm pieces to obtain a block-like (bulk) mixture.

The obtained block-like mixture had a water content of 2 0 70 ppm, a solid content of 96.0 wt%, and a weight average molecular weight M w of the polymer ^! Of 1 2 6 0 0 0 .

<< Drying process >>

The inside of the conical dryer (Nikko Industry Co., Ltd. product name: vacuum tumble dryer) used as a dryer is sufficiently replaced with nitrogen or compressed air (dry air) in advance, and the jacket is heated further. The medium was heated to 20 ° C. and the inside of the dryer was heated to 19 ° C.

The obtained block mixture (38.0 kg) was put into the dryer from the inlet of the dryer and fully tightened with a bolt and sealed.

Next, the valve was checked for opening and closing, and the inside of the dryer was depressurized with a vacuum pump. After confirming that the degree of pressure reduction was 6 Torr or less (79 8 Pa) or less and that there were no leaks, nitrogen was circulated in the dryer at 5 Lzmin. In this state (that is, the state where the internal temperature is 20 ° C., the flow of nitrogen 5 LZ min and the degree of reduced pressure 6 Torr or less (79 8 P a) or less), the mixture is held for 12 hours or longer. It was allowed to dry.

The block-like mixture (the positive electrode material composition of the present invention) obtained by the drying treatment as described above has a water content of 170 ppm and a solid content of 100 wt%. The weight-average molecular weight Mw is 1,2600, the molecular weight distribution (MwZMn) of the polymer is 1.40, and the content ratio of Li salt is 6. 9 wt%, and the conductive auxiliary agent is used. The content ratio of the electrode active material contained was 64.6 wt%.

[Example 4]

<< Preparation of polymer solution >>

In the same manner as in Example 1, a polymer solution (10) was obtained in which the weight average molecular weight Mw of the polymer was 1,240, and the solid content was 45.8 wt%.

<< Mixing process >>

(Mixture of polymer solution and Li salt)

A 0. 0 7 L bowl-shaped concentric stirring device (product name: manufactured by Sumitomo Heavy Industries, Ltd.) equipped with Maxplend wings was preheated under heating at 150 ° C, under a nitrogen stream, except the water in the apparatus, purged with nitrogen (1. and a pressure of up to 5 kg / cm ² to 0. 5 k gZcm ² Kai圧) performed four times, the Jiyakketto temperature to 7 0 ° C The temperature rose.

One part of the polymer solution (10) 25 4. 4 which had been heated and kept at about 80 ° C. in advance was charged into a stirrer by nitrogen pressure (0.5 kg / cm ² ).

Further, 2.48 parts of Li salt, which had been previously purged with nitrogen, was fed from the hopper to the stirring device with the vent opened. Thereafter, the stirrer was operated (Max blend wing: 20 rpm), and the internal temperature was changed to 71 ° C. (jacket temperature: 72 ° C.), and the mixture was stirred for 5 hours.

(Mixed with electrode active material containing conductive aid) 32. 84 parts of toluene and the aforementioned while flowing a small amount of nitrogen to a 0. 07 L vertical concentric stirring device (product name: Max Blend wings manufactured by Sumitomo Heavy Industries, Ltd.) equipped with Max Blend wings 2. 40 parts of the solution (mixture of polymer solution and L i salt) obtained in (mixture of polymer solution and L i salt) was charged, and the stirrer was operated (125 rpm). Next, divide the 20.53 parts of the electrode active material (made by US AVE STOR LLC, product name: vanadium oxide oxide / carbon blend) containing 1 to 8 wt% of carbon black as a conductive additive into five parts. Charged from the hopper for a minute. Thereafter, the internal temperature was adjusted to 35 (jacket temperature: 36 ° C.), and stirring was carried out for 2 hours to obtain a slurry. After completion of the stirring, the degassing operation of pressurizing the inside of the stirring apparatus to 1.6 kg cm ² with nitrogen and reducing the pressure to 10 O mmHg was repeated several times to remove excess water and dissolved oxygen in the system.

From the vertical concentric stirring device in which 21.68 parts of the mixture of the polymer solution and the Li salt described above were used for mixing the polymer solution and the Li salt, the 0. 07 L crucible equipped with the Max Blend wing was used. Nitrogen pressure 1. O kgzcm ² piping The temperature was about 100 ° C. through a pipe connected to the two concentric stirrers. Thereafter, the stirrer was operated (125 rpm), the internal temperature was set to 50 ° C. (jacket temperature: 52 ° C.) under normal pressure, and the mixture was stirred for 5 hours to obtain a slurry.

Thus, a slurry-like mixture (41) was obtained.

The mixture (41) has a solid content of 44.6 wt%, a polymer weight average molecular weight Mw of 120,000, and a content ratio of the electrode active material containing a conductive additive of 63.5 wt%, The content ratio of Li salt was 6.7 wt%, the evaluation of the dispersion state after mixing was “◎”, and the aggregate content ratio after mixing was 1.0%.

<< Degassing process >>

The jacket heat medium of 44 mm 媒 twin screw extruder (made by Japan Steel Works, product name: TEX44) is circulated, the heater is turned on, and the rear vent, the first vent to the fourth vent, the barrel, the head and the die are Heat to 110 ° C.

The inside of the stirring device containing the slurry-like mixture (41) in the above mixing step was pressurized to 0.05MPa with nitrogen, and a gear pump installed between the stirring device and the rear vent of the twin screw extruder After filling the mixture (41) until just before, rotate the 2 axes at a low speed and start supplying the mixture (41). Increase the rotation speed of 2 axes to 80 rpm and mix from the 2 die We confirmed that (41) came out. After that, start the vacuum pump, depressurize the retentate to 420 Torr, the 1st vent to 120 Torr, and the 2nd to 4th vents to 200 Torr, and then discharge from the biaxial die 15 A mixture (43) of rod-shaped bodies (circular column, diameter: 2.8 mm) was obtained at 3 kgzh.

The mixture (43) has a solid content of 98.8 wt%, a polymer weight average molecular weight Mw of 122,000, and a content ratio of an electrode active material containing a conductive additive of 63.5 wt%, The content ratio of Li salt was 6. 7 wt%.

<< Cooling and Solidification Process >>

The columnar mixture (43) obtained after volatilization is about 160 ° C. due to shear heat generated by biaxial rotation immediately after being extruded from a twin-screw die, but it is rolled at the same temperature. Two roll

(Kansai Roll Co., Ltd., Product name: 8 x 20 BOX type roll, temperature of front roll: 10 ° C, temperature of back roll: 10 ° C, guide width: 55 mm, rotation speed: 1.0 rpm) Thickness 2 A sheet of 0 mm in width and 10 O mm wide.

The sheeted mixture (43) was fed to a 2 m long duct for 0.25 mZ, and a cold air at a temperature of 9 ° C was applied at a wind speed of 1 mZ second to cool the sheet to a temperature below 30 ° C. .

Granulation process

While cooling the obtained sheet to a temperature of 15 ° C. or less with a spot cooler at a temperature of 9, the sheet is supplied to a sheet cutter (manufactured by Horai Co., Ltd., product name: SGE-220 type) 0. The mixture was charged at 7 kg / min, and was cut at a vertical blade rotational speed of 59. 2 Hz and a horizontal blade rotational speed of 100. OH z to obtain a square pellet-like mixture.

The obtained square pellet-like mixture is passed through a vibrating sieving machine (manufactured by Seishin Planning Co., Ltd., product name: ROTEX 1 302) to remove large foreign matter such as strings, etc., while eliminating shingles crickets. Supply hydrophobic silica fine particles (Aerosil R 9 72, manufactured by Nippon Aerosil) from a U-type vibration filter, and shake it into a square pellet-like mixture by approx.

The obtained square pellet-like mixture is 1.8 mm in thickness and 4. O mm in width, and the length is 70% or more of the whole based on the number basis and satisfies the range of 3.7 ± 0.5 mm, The average weight of one tablet was 41. Omg, the water content was 2050 ppm, the solid content was 99.0 wt%, and the weight average molecular weight Mw of the polymer was 121,000.

<< Drying / humidity control process >>

The inside of the Nauta mixer (made by Shinko Environmental Solutions, product name: SV mixer) to be used as a humidity controller is fully replaced with nitrogen or compressed air (dry air) in advance, and the heat medium of the jacket is further 24 ° 50 kg of the mixture in the form of square pellets was put into this humidity controller heated to 25 ° C. by heating to 25 ° C. from the inlet of the humidity controller, and then fully tightened with a bolt. I closed tightly.

Next, while stirring the Nauta mixer, water (about 75 g) equivalent to water of 1 500 ppm was sprayed from the spray nozzle, and after spraying, it was stirred and mixed for about 10 minutes. Thereafter, the mixture was allowed to stand for 4 hours so that the water content could reach equilibrium, and the above rectangular pellet-like mixture was dried and conditioned.

The square pellet-like mixture (the positive electrode material composition of the present invention) obtained by the drying and humidity control treatment as described above has a water content of 1 880 ppm and a solid content of 100 wt%. The weight average molecular weight Mw of the polymer is 120, 000, the molecular weight distribution (MwZMn) of the polymer is 1. 38, the content ratio of Li salt is 6. 8 wt%, and the conductive auxiliary agent is included. The content ratio of the electrode active material was 64. 6 wt%.

[Example 5]

<< Preparation of polymer solution >>

In the same manner as in Example 1, a polymer solution (10) was obtained in which the weight average molecular weight Mw of the polymer is 120,000 and the solid content is 45.8 wt%.

<< Mixing process >>

(Mixture of polymer solution and Li salt)

A 0. 07 L bowl-shaped concentric stirring device equipped with a Max Blend wing (Product name: Max Blend wing, manufactured by Sumitomo Heavy Industries, Ltd.) was previously heated under 150 ° C. under nitrogen flow. In the device Water was removed and replaced with nitrogen (1 to 5 k gZcm 0. S k and a pressure of up to ^{² gZcm 2} Kai圧) performed 4 times, and the temperature was raised to Jiyakketto temperature at 7 0.

One part of the polymer solution (10) 25 4. 4 which had been heated and kept at about 80 ° C. in advance was charged into a stirring apparatus by nitrogen pressure (0.5 kg z cm ² ). .

(Mixed with electrode active material containing conductive aid)

A small amount of nitrogen was allowed to flow through a 0.70 L type concentric stirring apparatus equipped with a log bone wing (product name: Log bone) manufactured by Shinko Environmental Solutions Co., Ltd. Toluene 2 4.0 2 parts and a polymer solution (10 1. 7. 7 parts were charged and the stirrer was operated (52 rpm). Then, an electrode active material containing 1 to 8 wt% of carbon black as a conductivity assistant (US AVE S TOR LLC, product name: Lithovanadium oxide carbon blend) 2 7. 4 9 parts in 5 times Divided and charged from the hopper over 10 minutes. Thereafter, the internal temperature was changed to 25 ° C. (jacket temperature: 24 ° C.), and stirring was performed for 2 hours to obtain a slurry. After completion of the stirring, nitrogen was used to pressurize the inside of the stirring apparatus to 1.6 kgzcm ² and decompress the pressure to 10 0 mm H g several times to repeat excess evaporation and remove excess water and dissolved oxygen in the system.

From the vertical concentric stirring device in which the above-mentioned mixture of polymer solution and Li salt 31 1.17 parts was used for mixing the polymer solution and Li salt, the logbone wing was mounted. 0.70 L Nitrogen pressure of 1.0 kg / cm ² and a pipe temperature of about 100 ° C. were introduced into a vertical concentric stirrer from a pipe connected to both stirrers. Thereafter, the stirrer was operated (30 rpm), the internal temperature was adjusted to 50 ° C. (jacket temperature: 52) under normal pressure, and stirring was carried out for 3 hours to obtain a slurry.

Thus, a slurry-like mixture (5 1) was obtained.

The mixture (51) has a solid content of 5 3. 1 wt%, a polymer weight average molecular weight Mw of 120, 00 0, and a content ratio of the cathode active material containing a conductive additive is 6 4 The content of L i salt is 6.2 wt%, and the evaluation of dispersion state after mixing is “◎”, and the content of aggregates after mixing is 1.2%. there were.

<< Degassing process >>

Turn on the heater of a 30 mm φ twin-screw extruder (manufactured by Plastic Engineering Laboratory, product name: BT-30-S 2) and set the temperature to 100 ° C for the first, second and third vents. Heat the 4th vent, 5th vent, the head and the die to 90 ° C.

The inside of the stirrer containing the slurry-like mixture (5 1) in the above mixing step was changed to

The pressure is increased to 0. 5MPa, and the gear pump installed between the stirring device and the first vent of the twin screw extruder fills the mixture (51) just before the first vent, and then the twin screw is operated at low speed. Then, the mixture (51) was supplied, the rotational speed of the two shafts was increased to 100 rpm, and it was confirmed that the mixture (51) came out of the twin shaft. After that, start the vacuum pump and reduce the pressure of the second vent to 3 4 9 Torr, and the third vent to 6 9 Torr, and discharge the rod from the biaxial die at 6 kg Zh (cylindrical, A mixture (5 3) of diameter: 25 mm) was obtained.

The compound (5 3) has a solid content of 98.5 wt%, and the weight average molecular weight Mw of the polymer is

1 2 1 00 0, and the content ratio of the electrode active material containing the conductive additive is 6 3 6 wt%, The content ratio of L i salt was 6.6 wt%.

Granulation process

A hot cutter capable of rotating a piano wire (wire diameter 0.3 mm, length 5 m) in about 1.7 mm Z seconds is installed at the end of the single tube at the outlet of the twin screw extruder, and discharge from the single tube The mixture (53) of the rod-like body (25 mm in diameter) at 90 to 120: was cut into pieces of about 25 cm in length to obtain a block-like (bulk) mixture.

The obtained block mixture had a water content of 250 ppm, a solid content of 98.6 wt%, and a polymer weight average molecular weight Mw of 121,000.

<< Cooling and Solidification Process >>

The obtained block-like mixture (53) is dropped on a wire mesh belt, vibrated, and sent at 0.5 mz min. Cold air with a temperature of 5 to 10 ° C. at a wind speed of 1 to 1.5 mz seconds And cooled until the block temperature was below 30 ° C.

<< Drying / humidity control process>

The inside of the metal hopper used for humidity control is fully replaced with compressed air with a dew point of 1 to 5 (dry air), and 50 kg of the block-like mixture is put in from the inlet and tightened with a bolt. It was sealed. Next, compressed air (dry air) having a dew point of 15 ° C. to 0 ° C. was flowed from the lower portion of the hopper for 4 hours to make the water content equilibrate, and the above block mixture was dried and moisture-conditioned.

The square pellet-like mixture (the positive electrode material composition of the present invention) obtained by the drying and moisture conditioning treatment as described above has a water content of 1620 ppm and a solid content of 100 wt%. Weight average molecular weight Mw is 120, 000, polymer molecular weight distribution (Mw / Mn) is 1. 38, content ratio of Li salt is 6. 8 wt%, electrode active containing conductive auxiliary agent The substance content ratio was 64. 4 wt%.

[Example 6]

<< Preparation of polymer solution >>

<< Mixing process >>

(Mixture of polymer solution and Li salt)

A 0. 07 L bowl-shaped concentric stirring device (product name: manufactured by Sumitomo Heavy Industries, Ltd.) equipped with a Maxplindo wing was previously heated under 150 ° C under nitrogen flow. The water content in the apparatus was removed at this point, nitrogen substitution (pressurization to 1.5 kg zcm ² and pressure release to 0.5 kg zcm ² ) was performed four times, and the jacket temperature was raised to 70 ° C.

27. 76 parts of the polymer solution (10) which had been preheated and kept at about 80 was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ).

Further, 3.33 parts of L i salt previously purged with nitrogen were fed from the hopper into the stirring device with the vent opened. Thereafter, the stirrer was operated (Max Blend wing: 20 rpm), the internal temperature was set to 70 ° C. (jacket temperature: 71 ° C.), and stirring was carried out for 6 hours.

(Mixed with electrode active material containing conductive aid)

0. 07 L bowl-shaped concentric stirring device equipped with Max Blend wings (Product name: Max Bure 32. 80 parts of toluene and 4.38 parts of the polymer solution (10) were charged into a wing of Sumitomo Heavy Industries, Ltd., while flowing a small amount of nitrogen, and the stirrer was operated (125 rpm). The internal temperature was 35 ° C. (jacket temperature: 36 ° C.), and the mixture was stirred for 1 hour. Then, an electrode active material containing 1 to 8 wt% of carbon black as a conductive additive (US AVE S TOR LLC, product name: vanadium oxide oxide <carbon blend) 20. 53 parts in five divided portions Charged from the hopper over 11 minutes. Thereafter, the mixture was stirred and mixed at an internal temperature of 35 (jacket temperature: 36) for 2 hours to obtain a slurry. Thereafter, the inside of the stirring apparatus was pressurized to 1.6 kg / cm ² with nitrogen and depressurized to 10 O mmHg several times to repeat excess evaporation and remove excess water and dissolved oxygen in the system.

From the vertical concentric stirring device in which 19.74 parts of the mixture of the polymer solution and the Li salt described above were used for mixing the polymer solution and the Li salt, a 0. 07 L crucible equipped with the Max Blend wing was used. Nitrogen pressure was 1.0 kg / _C m ² and piping temperature was about 100 ° C from a pipe connected to a concentric stirring device. Thereafter, the stirrer was operated (125 rpm), the internal temperature was adjusted to 49 ° C. (jacket temperature: 50 ° C.) under normal pressure, and stirring was carried out for 5 hours to obtain a slurry mixture (61).

The slurry-like mixture (61) (the positive electrode material composition of the present invention) obtained as described above has a solid content of 44.6 wt%, a polymer weight average molecular weight Mw of 120,000, The content ratio of the electrode active material containing the auxiliary agent is 63.5 wt%, the content ratio of Li salt is 6.7 wt%, and the evaluation of the dispersion state after mixing is “◎”. The aggregate content of C was 0.2%.

A positive electrode of a lithium secondary battery was produced using the positive electrode material composition obtained in each of the above examples, and the battery performance was evaluated. As a result, lithium based on the positive electrode material composition obtained in any of the examples was used. The lithium battery also exhibited good performance. Industrial applicability

The production method of the present invention is suitable as a method for preparing a material composition that can be used for the positive electrode of a lithium secondary battery.

Claims

The scope of the claims

1. In a method of obtaining a positive electrode material composition comprising a polymer, an electrolyte salt compound, an electrode active material and a conductive aid as an essential component, mixing of the electrolyte salt compound, the electrode active material and the conductive aid with the polymer is The step (I) of mixing only the electrolyte salt compound into a solution in a dissolved state first, and the step of mixing the electrode active material and the conductive aid simultaneously or before or after the mixture after mixing the electrolyte salt compound into the polymer (II A method of producing a positive electrode material composition for a lithium secondary battery, characterized in that the method is carried out separately.

2. The method for producing a positive electrode material composition for a lithium secondary battery according to claim 1, wherein both or one of the step (I) and the step (II) is performed in the presence of a solvent.

3. The lithium secondary according to claim 2, further comprising the step of volatilizing the solvent in the mixture to the extent that the obtained mixture does not lose fluidity after the step performed in the presence of a solvent. The manufacturing method of the positive electrode material composition for batteries.

4. At least one of the steps of cooling and solidifying the mixture to be the positive electrode material composition, granulating the mixture, and drying or conditioning the mixture. 3. The manufacturing method of the positive electrode material composition for lithium secondary batteries as described in 3.

5. A step of cooling both the step (I) and the step (II) in the absence of a solvent, and cooling and solidifying the mixture to be the positive electrode material composition after the step (I) and the step (II) The positive electrode material composition for a lithium secondary battery according to claim 1, further comprising the steps of: granulating the mixture; and at least one of the steps of drying and Z or conditioning the mixture. Production method

6. The method for producing a positive electrode material composition for a lithium secondary battery according to any one of claims 1 to 5, wherein at least one step is performed under an inert gas atmosphere.

7. The weight average molecular weight of the polymer is Mw. When the weight average molecular weight of the polymer in the mixture after the final step is Mw, the weight average molecular weight reduction rate (D _Mw ) determined by the following formula (1) is 10% or less. A method for producing a positive electrode material composition for a lithium secondary battery according to any one of the above 6.

D _Mw (%) = [(Mw _0- Mw) / Mw ₀ ] XI 00 (1)

.

8. The electrode active material is L i _x V _y O _z (where x, y and z are each independent of each other, and 0 x く 2, y = (mx + 2 z) / n and z = (mx + ny) / 2 (where, m is a valence number of Li and n is a valence number of V and is a real number of 4 or more)). 7. A method of producing a positive electrode material composition for a lithium secondary battery according to any one of 7 to 7. -

9. The method for producing a positive electrode material composition for a lithium secondary battery according to any one of claims 1 to 8, wherein the polymer is an ionically conductive polyether polymer.