WO2006025604A1

WO2006025604A1 - Process for producing positive electrode material composition for lithium secondary battery

Info

Publication number: WO2006025604A1
Application number: PCT/JP2005/016471
Authority: WO
Inventors: Alan Vallee; Paul-Andre Lavoie; Fumihide Tamura; Izuho Okada; Kazuo Takei; Masamitsu Sasaki; Taketo Toba
Original assignee: Avestor Limited Partnership
Priority date: 2004-09-03
Filing date: 2005-09-01
Publication date: 2006-03-09

Abstract

A process for producing a positive electrode material composition for lithium secondary battery, in which in the mixing of a polymer, an electrode active material and a conduction aid, uniform mixing can be conducted while satisfactorily suppressing any decomposition and deterioration of the polymer, and in which high productivity in time and cost can be achieved with satisfactory attention paid to environment. There is provided a process comprising the steps of mixing a polymer solution, an electrode active material and a conduction aid together to thereby obtain a slurry mixture and evaporating the solvent of the polymer solution from the slurry mixture to such an extent that the mixture retains fluidity.

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. The main component is lithium salt (electrolyte salt), which is a source of L i ⁺ to be dissociated.

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 Z 7 5 3 7 5 Breadlet

[Patent Document 2] International Publication No. 0 3/9 2 0 1 7 Panfleet

[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

However, in order to exhibit excellent battery performance, it is necessary that the polymer, the electrode active material, and the conductive material are sufficiently uniformly mixed among the components, and in the method of the above (i) Since it is necessary to apply a high shear force during melt-kneading, which causes excessive shear, degradation of the polymer (specifically, reduction in weight average molecular weight) becomes significant. was there. Specifically, among the components constituting the positive electrode portion of the lithium secondary battery, as for the electrolyte salt, generally, it is common to mix and blend a polymer, an electrode active material and a conductive material upon extrusion molding. Therefore, it is important to first obtain a uniform mixture of polymer, electrode active material and conductive material, but in the method of (i), the polymer and electrode active material / conductive material At the stage of mixing with the polymer, the degradation of the polymer occurs.

In addition, in the method (ii) above, it is necessary to use a large amount of solvent that can be cast into a predetermined shape, after which the solvent must be sufficiently volatilized. ), And it is not possible to recover and reuse the volatilized solvent, and the productivity is inferior in terms of time and cost. so There was also a problem.

Therefore, the problem to be solved by the present invention is that, when mixing the polymer, the electrode active material and the conductive auxiliary agent, the polymer can be uniformly mixed while sufficiently suppressing the degradation and deterioration of the polymer. · It is an object of the present invention to provide a method for producing a positive electrode material composition for a lithium secondary battery, which is excellent in productivity in terms of cost and capable of sufficiently giving consideration to the environment. Means to solve the problem

The present inventors diligently studied to solve the above-mentioned problems. As a result, when the polymer, the electrode active material and the conductive auxiliary agent are mixed as a component of the positive electrode portion of a lithium secondary battery, a polymer in solution (for example, a polymer solution obtained by solution polymerization) is used as the polymer. Thus, each component is sufficiently uniformly mixed, and a step of obtaining a slurry-like mixture, and volatilizing a solvent in a polymer solution subjected to the mixing from the slurry-like mixture, for example, heating is carried out. It has been found that the above-mentioned problems can be solved at once by providing the step of mixing the solvent so that the mixture loses fluidity, and volatilizing the solvent to a certain extent. The present invention has been completed.

Therefore, a method of producing a positive electrode material composition for a lithium secondary battery according to the present invention comprises: mixing a polymer solution, an electrode active material, and a conductive auxiliary agent to obtain a slurry-like mixture; Volatilizing the solvent in the polymer solution from the slurry-like mixture to such an extent that it does not lose its polarity. Effect of the invention

According to the present invention, when mixing a polymer, an electrode active material, and a conductive auxiliary agent, uniform mixing can be performed while sufficiently suppressing degradation and deterioration of the polymer, and in addition, in terms of time and cost. It is possible to provide a method for producing a positive electrode material composition for a lithium secondary battery, which is excellent in productivity and capable of sufficiently giving consideration to the environment. 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.

The production method of the present invention comprises, as described above, the step of mixing the polymer solution, the electrode active material and the conductive auxiliary agent to obtain a slurry-like mixture (mixing step), and the above-mentioned mixture does not lose its fluidity. Volatilizing the solvent in the polymer solution from the mixture in the form of a slurry (devolatilization step) is important.

Hereinafter, first, the mixing step and the degassing step, 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 and the production method of the present invention The positive electrode material composition to be produced will be described.

[Mixing process]

A polymer solution generally refers to a solution in which a polymer is dissolved in a solvent, but With regard to the polymer solution that can be used in the mixing step in the present invention, the above-mentioned dissolved state may be obtained before the start of mixing with other components, or even after the start of mixing (during mixing). Well, not limited. Therefore, in carrying out the mixing step (at the start of mixing), a polymer may be dissolved in the solvent from the beginning, or a polymer in which the polymer is previously dissolved may be used. One and a solvent capable of dissolving the polymer may be used independently or in combination, and these may be used in combination without limitation. Specifically, as a polymer solution which can be used in the mixing step, for example, a reaction solution after polymerization reaction obtained when a polymer is synthesized by a solution polymerization method or the like, or a polymer synthesized by precipitation polymerization or the like. A solution obtained by isolating one and dissolving it in a solvent capable of dissolving it, and the like are preferably mentioned. Among them, the solution polymerization method is excellent in productivity and easy to remove the heat of reaction, and thus is excellent in safety. Therefore, the reaction solution obtained by the method is more preferable.

The polymer is preferably an ionic conductive polyether polymer, and examples thereof include an ethylene oxide copolymer (nonionic alkylene oxide water soluble copolymer) 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 mainly containing a constituent component derived from an ethylene oxide monomer in its molecular structure and having an ether bond in the main chain. 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) ataryloyl group and an alkenyl group) others - CH ₂ -0- Re- Ra group (Re has, - (CH ₂ - C¾_0) is (p has the structure of p- integer) from 0 to 10) and a substituted Okishiran compound represented by) Polymers obtained by polymerizing comonomers are preferred. It is preferable that this polymerization be ring-opening polymerization of each raw material monomer oxysilane group.

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, 2-epoxyhexane, 1,2-epoxyoctane, cyclohexenoxide and styrene oxide, or methyl glycidyl ether, ethyl dalysidyl ether and ethylene daryl methyl dalysyl ether, etc., and further, substituents In the case where is a crosslinkable substituent, that is, when the substituent has an aryl group, an alkenyl group, an acryloyl group, a methacryl group, etc., epoxybutene, 3, 4-epoxy — 1 — pentene, 1 , 2-Epoxy 1 5, 9-Cyclo dodecadi Emissions, 3, 4-epoxy one 1-hexene into single Byurushikuro, 1, 2-epoxy one 5- Shikurookuten, glycidyl acrylate, methacrylic acid Cyclohexenyl ether base two glycidyl ether, the consequent opening - Darishijiru, hexanoate sorbic acid glycidyl Contact Yopi glycidyl one 4 to _, or bi Nirudarishiji / milled by wet one ether, § Li glycidyl ether, - Byurushiku port to Kishirugurishi Jinoreeteru, _a Mention may also be made of methyl daricidyl ether, 4-vinylbenzyl glycidyl ether and 4-arylbenzyl glycidyl ether. 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 crosslinkable substituent (where the substituent is a crosslinking substituent), by using an ethylene oxide copolymer as a cross-linked body. Is preferred.

The weight average molecular weight (Mw) of the ethylene oxide copolymer is not limited, but is preferably 2 0, 0 0 5 to 5 0 0, 0 0 0, more preferably 3 0, 0 0 0 ~ 3 0 0, 0 0 0, more preferably 4 0, 0 0 0 to 2 0 0, 0 0 0. If the weight average molecular weight is less than 20 000, there is a risk that tack will occur in the positive electrode material after molding, and if it exceeds 500 000, molding of the positive electrode material becomes difficult, and processing There is a risk of deterioration 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. When the molecular weight distribution is more than 3, tackiness may occur in the molded positive electrode material, resulting in poor handling, and the battery performance may be degraded due to the inclusion of low molecular weight substances.

The solvent which can be used as the solvent is preferably a nonpolar solvent in that it does not adversely affect the battery performance. For example, aromatic hydrocarbon solvents such as benzene, toluene, xylene and ethylbenzene; heptane, octane, n- Aliphatic hydrocarbon solvents such as xanthan, n-pentane, 2, 2, 4-trimethylpentan; alicyclic hydrocarbon solvents such as cyclohexane, cyclopentane, methylcyclohexane and the like; jetyl ether, dibutyl ether Ether solvents such as methyl pentyl ether; Solvents of ethylene diallyl dialkyl ethers such as dimethoxetane; Cyclic ether solvents such as THF (tetrahydrofuran) and dioxane; Organic solvents containing no active hydrogen such as hydroxyl group such as Among them, toluene and xylene are preferred. Particularly preferred is one containing no water at all.

The content of the polymer in the polymer solution is preferably, but not limited to, 20 to 70% by weight, more preferably 25 to 65% by weight, and still more preferably 30 to 60% by weight. %. If the polymer content is less than 20% by weight, the productivity of the polymer and thus the productivity of the positive electrode material composition may be extremely reduced. If it is more than 70% by weight, the polymer solution The viscosity may increase and mixing may be difficult.

The content of the solvent in the polymer solution is not limited, but is preferably 30 to 80% by weight, more preferably 35 to 75% by weight, and still more preferably 40 to 70% by weight. It is%. If the solvent content is less than 30% by weight, the viscosity of the polymer solution will be high, which may make mixing and stirring difficult, and it may also be difficult to feed and transfer the mixing apparatus itself. Excessive sure may occur during mixing, which may promote polymer deterioration and molecular weight reduction. If it exceeds 80% by weight, the productivity of the polymer and hence the productivity of the positive electrode material composition may be extremely reduced, and the amount of the solvent contained in the mixture after the mixing step is increased. The productivity may be impaired when the solvent is volatilized in the subsequent degassing step. In the present invention, all the solvents used in the mixing step (that is, all the solvents contained in the slurry mixture obtained in the mixing step) are handled as the solvent in the polymer solution. Therefore, for example, when a reaction solution obtained by solution polymerization method is used as a polymer solution, a solvent used for the polymerization is usually a solvent in the polymer solution, but in the mixing step, the reaction solution is further separated from the reaction solution. When a solvent is added, the added solvent is also treated as a solvent in the polymer solution, and the amount of the solvent in the polymer solution as mentioned above is different from the solvent in the reaction solution (the solvent used for polymerization) separately. It becomes the total amount with the added solvent.

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-mentioned reaction initiator include alkaline catalysts such as sodium hydroxide, potassium hydroxide, potassium carbonate, sodium alcoholate, potassium carbonate and sodium carbonate, and metals such as, for example, potassium metal and sodium metal, for example, water oxidation Aluminum · Magnesium fired product (Japanese Patent Application Laid-Open No. 8 2 8 9 1 9 etc.), Metal-ion-added magnesium oxide (Japanese Patent Publication No. 6 1 5 0 3 8, Japanese Patent Application Laid-Open No. 7 2 2 5 5 4 No. 0 etc.) and calcined hydrotalcites (Japanese Patent Application Laid-Open No. Hei 2 7 8 4 1 etc.) A 1 -M g complex oxide catalysts such as or catalysts obtained by surface modification of them 3 3 4 7 8 2), barium oxide, barium hydroxide (JP-A 5 4-75 18 7 etc.), layered compounds (Japanese Patent Application Laid-Open No. 6-5 0 5 9 8) 6), Strontium Oxides, strontium hydroxides (JP-B 6 3 250 5 etc.), calcium compounds (JP-A 2 34 6 3 6 etc), cesium compounds (JP-A 7- 7 0 5 Preferred are metal 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, 1 0, 00 at 95 ° C. It is 0 to 4 5, 0 0 centimoise, more preferably 1 5 0 0 0 to 3 5 0 0 0 centi Boiling at 95 ° C. When the viscosity is less than 1000 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 cathode material composition If the reaction solution obtained by the solution polymerization method is used as a polymer solution, for example, it may cause an extreme decrease in product productivity, and if it exceeds 600 centipoise at 95.degree. The viscosity may be too high even during the polymerization reaction, which may make it difficult to stir and the like.

The use ratio of the polymer solution in the mixing step is not limited, but is preferably 15 to 60 weight ° / ₀ with respect to the total amount (total amount of all the raw materials used in the mixing step), for example. It is preferably 20 to 55% by weight, more preferably 25 to 50% by weight. If the amount of the polymer solution is too small, the productivity of the positive electrode material composition may be extremely reduced. On the other hand, if the amount of the polymer solution is too large, it may be uniform with the electrode active material or the conductive aid, although it depends on the concentration. There is a possibility that the viscosity may be lowered after the addition of the electrode active material, etc., and mixing and stirring may become difficult. In addition, the amount of the solvent contained in the mixture after the mixing step increases. When the solvent is volatilized in the subsequent degassing process, the productivity may be impaired. An electrode active material generally refers to a host compound having an activity of accepting lithium ion as a guest in order to insert and desorb lithium ions, and an electromotive force required in a lithium secondary battery Reaction amount (energy density) It is an essential component to obtain 'reversible' ion conductivity. As compounds that accept lithium ions as guests, 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 composite oxides containing lithium as the metal element (a L i Co0 _2, L i N I_〇 _{_{_{2, L iMn 2 0 4,}}} L i F E_〇 ₂ etc.) and the like. the present mixing process in the invention The electrode active material which can be used is not particularly limited as long as it is usually used for the positive electrode of a lithium secondary battery, but, for example, lithium vanadium composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide things, lithium nickel composite oxides, but vanadium oxide and the like, among them, a lithium vanadium composite oxide, _{_{_{ie, L i x V y O z}}} ( however, x, y and z are each independently And, 0 <x ≤2, y = (mx + 2 z) / n Oyopi _{¾ = (mx + ny) /} 2 ( provided that, m is the valence of L i, n is the valence of V It is a real number satisfying 4.) Force Lithium ion introduction / desorption is performed more efficiently, and it is particularly preferable in that it has a large capacity (high energy density) Electrode active material The active material is generally in the form of a solid powder and is dispersed in a slurry-like mixture obtained after the mixing step. It becomes a state.

The proportion of the electrode active material used in the mixing step is not limited, but is preferably, for example, 0.1 to 50 times the weight of the polymer in the polymer solution, and more preferably 0.3. It is preferably 20 to 20 times, more preferably 0.5 to 10 times. When 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, when the amount of the electrode active material is too large, the forming of the positive electrode material may be difficult.

The conductive aid may be any one as long as it is usually used for a positive electrode of a lithium secondary battery, and is not limited, and examples thereof include acetylene black, ketjen black, Graphite and the like. The conductive aid may be used alone or in combination of two or more. The conductive aid is generally in the form of a solid powder and is in the state of being dispersed in the slurry-like mixture obtained after the mixing step.

Although the use ratio of the conductive auxiliary in the mixing step is not limited, for example, it 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. If the amount of the conductive additive is too small, the conductivity of the positive electrode may be insufficient. On the other hand, if the amount of the conductive additive is too large, the forming of the positive electrode material may be difficult. In the mixing step, when mixing the polymer solution, the electrode active material, the conductive auxiliary agent, and various additives as needed, the order of mixing the respective components is not limited. For example, the electrode active material and the conductive auxiliary agent may be added separately or in a mixture before being added to the polymer solution in which the polymer is dissolved in the solvent. The electrode active material and the conductive aid may be separately or separately mixed (two of the polymer, the electrode active material and the conductive aid may be mixed, or three may be mixed). May be added. In addition, a solvent can be added to the electrode active material or the conductive auxiliary in advance. In the mixing step, various additives such as, for example, anti-aging agents, light stabilizers, lubricants, antistatic agents, reinforcing agents and fillers may be appropriately mixed, as required, within the range that does not impair the effects of the present invention. be able to.

In the mixing step, a polymer solution, an electrode active material, a conductive auxiliary agent, and various additives as necessary are mixed to obtain a slurry-like mixture, but the method of mixing is not limited. A mixing method using a conventionally known mixing apparatus or mixing-capable apparatus 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 the contents under desired conditions is preferred. 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 spur blend blade (inner blade: Max-blend wing, Outer wing: Spiral-type concentric twin-screw stirring device (for example, product name: Super-blend, manufactured by Sumitomo Heavy Industries, Ltd.), Max-blend wing (Sumitomo Heavy Industries, Ltd. Co., Ltd.), a full zone wing (Shinko Pantech Co., Ltd.), a super mix wing (Satake Chemical Machinery Co., Ltd.), a H-IF mixer (Shonken Chemical Co., Ltd.) Stirrer equipped with a), Stirrer equipped with a Sunmera wing (Mitsubishi Heavy Industries), Log bone (Shinko Panthe Manufactured by Hitachi, Ltd., a stirrer mounted with VCR (Mitsubishi Heavy Industries, Ltd.), torsion grid blades (manufactured by Hitachi, Ltd.), turbine blades, paddle blades, Faudle blades, Bull margin blades, propeller blades, etc. Stirring devices mounted thereon are preferably mentioned. Among them, a bowl-shaped concentric biaxial stirring device mounted with a super blend blade, a stirring device mounted with a helical ribbon blade, a stirring device mounted with a double helical ribbon blade, and a Max blend blade More preferred is a stirrer equipped with a container and a stirrer equipped with a log bone. In addition, horizontal stirring mixers equipped with screw patterns for kneading, for example, KRC kneader (manufactured by Kurimoto Coffee Co., Ltd.), twin-screw extruder (for example, products Name: SUPERTEX a II, manufactured by Japan Steel Works Co., Ltd .; Product name: BT — 30 — S 2, manufactured by the Institute of Plastics Engineering, and the like.

In the mixing step, it is preferable to mix the polymer solution, the electrode active material, and the conductive auxiliary agent so that they can be made into a slurry-like mixture in a uniformly dispersed state. By making each component into a slurry-like mixture in a uniform dispersion state, it is possible to obtain a positive electrode material composition that exhibits excellent battery performance (for example, cycle characteristics (charge-discharge characteristics, etc.)). Achieving a slurry-like mixture in a uniform dispersion state can also be achieved, for example, by appropriately setting the operating conditions of the mixing apparatus used for mixing (for example, the type of impeller, rotational speed, etc.). You can In addition, the polymer is dissolved in a solvent in advance to form a polymer solution, and a part of the polymer solution is first mixed with the electrode active material and the conductive aid, whereby the compatibility between the electrode active material and the conductive aid and the solvent is obtained. It is also effective to use the technique of adding and mixing the remaining polymer solution after the improvement, to obtain a slurry-like mixture in a uniformly dispersed state. When adopting such a method, the amount of polymer solution to be first mixed with the electrode active material and the conductive auxiliary agent is 0.5 to 2 with respect to the total amount of solvent used in the mixing step for the amount of polymer solid content in the polymer solution. It is preferable that the content be 0% by weight, more preferably 1 to 10% by weight, and still more preferably 2 to 7% by weight. In the present invention, a method of evaluating whether or not the toner is in a uniformly dispersed state will be described in the examples to be described later. [Volatilization process]

In the volatilization step, the solvent is volatilized from the slurry mixture after the mixing step under, for example, conditions of heating and the like so that the mixture is obtained in the flowable state. The mixture obtained after the degassing step 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 degassing, an apparatus used for degassing, and various conditions, a method which can be adopted for normal degassing, a usable apparatus, conditions to be set, and the like may be adopted. Details are shown 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 suitable, but depending on the type of mixture to be degassed (especially the type of polymer), etc. Even if there is a two-step process The same effect may be obtained in some cases, so it may be selected appropriately according to the processing object. The apparatus used for degassing (degassing apparatus) includes, but is not limited to, a stirred tank evaporator, a downstream liquid column evaporator, a thin film evaporator, a surface renewal type polymerizer, a kneader, a roll mixer, An intensive mixer (so-called Banbury-one mixer), an extruder, etc. are preferably mentioned, and it is preferable to carry out using at least one of these apparatuses. 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 Wing: 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 circle: Pyramid Ripon wing Type reactor (manufactured by Mitsubishi Heavy Industries, Ltd.) and the like are preferably mentioned. 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. In addition, when these are used, the evaporation process is carried out by updating the heat transfer surface.

Among the various stirring vessel evaporators described above, particularly, in the case of a bowl-shaped concentric biaxial stirring vessel, the following excellent features such as (i) to (vi) can be mentioned. (I) A wide range of treated viscosity range, and excellent mixing performance can be exhibited 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 condition, (iii) uniform the liquid flow velocity in the inner wall of the tank and in the inner part of the tank Can maintain high temperature uniformity and reduce the degradation of polymer quality

(Iv) Slip and retention of low viscosity liquid on high viscosity fluid is eliminated, and dispersibility of reflux reflux liquid and various additives after polymerization can be improved, (V) High concentration slurry processing It can eliminate adhesion and deposition on the tank wall and baffles at the time, and exhibits good slurry dispersibility. (Vi) Stable wall flow velocity due to the outer wing rotating close to the tank wall, Adhesion of the inner wall and cleaning time in the tank · The number of times can be reduced.

As the downstream liquid column evaporator, a multi-tubular heat exchanger type (for example, product name: Sulthe-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 throughput can be performed. Can also respond. In the case of a multi-tubular heat exchanger type, the evaporation process is performed by expanding the interfacial area ^^, the corresponding maximum processing viscosity is preferably 5 0, 0 0 0 Boise, and in the case of a plate heat exchanger type It is preferable that the evaporation process is performed by heat transfer area expansion, and the corresponding maximum processing viscosity is 10.000 Boise.

The thin film evaporator is excellent in that a centrifugal force is exerted by the plate 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.) And 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, horizontal and tank types are not common, but wedge type is 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. It is preferable that the high-viscosity liquid is more suitable than the low-viscosity liquid because the vertical thin-film evaporator descends by its own weight, and the corresponding maximum processing viscosity of the movable blade type is 1,200 Boise. Further, 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 1 0 0 0 0 0. 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 1000 boise.

Surface renewal type polymerizer (horizontal type thin film polymerizer) shows high degassing performance by renewal of gas and liquid surface (For example, Product name: Vivolac, manufactured by Sumitomo Heavy Industries, Ltd .; Product name: Hitachi Eyeglass Wing Polymerizer) Product name: Hitachi lattice 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 and liquid surface renewal.

Kneaders (for example, Product Name: KRC KNEIDA., Manufactured by Kurimoto Soto Co., Ltd.), roll mixer, and intensive mixer (so-called Banbury-one mixer) are suitable for mixing high-viscosity melts, etc. It 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 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 cleaning 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 1 0 0 0 0 Boise. Is preferred.

An extruder is suitable for mixing of a high viscosity melt and the like, and has an addition function of heating, melting, kneading, and devolatilizing ability. For example, a single-screw extruder, a twin-screw extruder (for example, product name) : S

UPERTEX a II, manufactured by Japan Steel Works, Ltd .; Product name: BT-30-S 2, Plastics Engineering Research Laboratories), 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 a very viscous product, and the evaporation process is carried out by kneading and evaporation etc. In the extruder, a single screw type is used. The corresponding maximum processing viscosity is preferably 100, 00 Boise for both of the two and the biaxial type.

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. Further, although a thing which can be preferably used for the present volatilization is not limited, a twin-screw surface renewal type polymerizer, a kneader, a twin-screw extruder and the like can be mentioned.

When the degassing step is carried out, degassing may be carried out by directly connecting the various degassing devices listed above to the so-called pre-stage apparatus provided in the mixing process, or liquid transfer or transfer from the above-mentioned pre-stage apparatus provided in the mixing process. After that, it is possible to carry out the degassing with various degassing devices. For the former, for example, the pre-stage unit and the degassing unit are combined with various liquid feed pumps (eg gear pump (trade name: gear pump, manufactured by Shimadzu Corporation), mono pump (eg product name: mono pump, equipped with logistics) Co., Ltd.))) And the form etc. which are directly connected. For the latter, for example, a form in which a liquid transfer line is connected between the pre-stage device and the degassing device, or an intermediate tank equipped with a jacket and a stirrer between the pre-stage device and the degassing device An example is the one provided with a tank (cushion tank).

In the volatilization step, the concentration of the residual solvent in the mixture after volatilization is preferably 0.01 to 30% by weight, more preferably 0.05 to 20% by weight, and still more preferably 0.1 to 1%. It is 10% by weight. The above residual solvent concentration is 0.01 weight. /. If it is less than 30% by weight, the degassing conditions need to be strict, which may lead to thermal degradation of the positive electrode material composition (particularly polymer) and the battery performance may be deteriorated. The material composition may be tacked to cause blocking or the like, or the battery performance may be degraded. In the volatilization step, it is preferable to adjust the water content of the mixture (especially the polymer) after the volatilization together with the degassing of the solvent. Water is contained, for example, in the solvent or monomer used during the polymerization reaction, or in the solvent added separately. Specifically, the water content is preferably adjusted to 5,000 ppm or less, more preferably 500 ppm or less, and still more preferably 200 ppm or less. If the water content exceeds the above range, the lithium salt may react with the water contained in the 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 / or to increase the degree of reduced pressure at the time of the devolatization treatment. To do is to lower the pressure, and to reduce the degree of decompression 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 there is a risk of thermal degradation of the mixture (especially polymer) after volatilization, consider these and set as appropriate. 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 the temperature is too small, it may not be possible to control the water content to 200 ppm or less unless the degassing temperature is raised significantly. Set these values appropriately in consideration of these.

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 to 150 ° C. By degassing in this temperature range, after degassing, a mixture of the above-mentioned desired residual solvent concentration and water content can be obtained. If the temperature is less than 40, the remaining solvent may increase. If the temperature exceeds 300 ° C., the mixture after evaporation (especially the polymer) may be thermally deteriorated or thermally decomposed. Here, the above-mentioned temperature means the temperature of the positive electrode material ^ ′ ′ composition when a stirred tank evaporator is used, and other devolatilizers (eg, surface renewal type polymerizer, kneader, extruder, etc.) When used, it is assumed that the temperature of the jacket or heater portion of the degassing apparatus is preferably carried out under a pressure of 1,000 to 100 ° P a, more preferably 2, The pressure is preferably 500 to 70,000 Pa, more preferably 5 to 40,000 Pa. By carrying out the volatilization in this pressure range, after the volatilization, it is possible to obtain the desired residual solvent concentration and water content as described above. It is possible to obtain a mixture where the pressure is less than 1,0 O OP a In this case, the solvent may flash and forming may occur, and if it exceeds 100 ° a, the temperature must be applied to the extent that the mixture after evaporation (especially the polymer) decomposes The case arises. Here, the pressure is the pressure in the tank of the degassing apparatus. In the volatilization step, the viscosity of the mixture after volatilization is preferably such that it becomes 1,00 0 to 5, 0 0 0, 0 0 0 with 100, more preferably 1 0 It is 5, 0 0 0-4, 0 0 0, 0 0 0 bid at 0 ° C, more preferably 1 0, 0 0 0 3, 0 0 0, 0 0 0 bid at 100 ° C. In the case where the viscosity is less than 1000 in 100, the amount of the remaining solvent is large, and there is a risk that foaming may occur when the positive electrode material composition is formed, If the temperature exceeds 5,00 0 0 0 0 0 0 ° C., degassing in the degassing apparatus may be difficult.

The manufacturing method of the present invention is a manufacturing method essentially including the mixing step and the degassing step, and the mixture obtained in the degassing step can be used as it is as a positive electrode material composition.

In the production method of the present invention, it is preferable to further include other steps. Specifically, the step of cooling and solidifying the mixture to be the positive electrode material composition (cooling and solidifying step), the step of granulating the mixture (granulating step), and the step of drying and / or controlling the humidity of the mixture (drying and drying It is preferable to include at least one of a process and Z or a humidity control process). The cooling / solidifying step, the granulation step, the drying / humidifying step may be performed in any order, but it is preferable to carry out in the order described. The steps of cooling and solidifying, granulating, drying and moisture control, and the steps associated with these steps will be described in detail below.

[Cooling and solidification process]

The cooling and solidification step is for cooling and solidifying (hardening) the mixture to be the positive electrode material composition. If the mixture to be subjected to the cooling and solidifying step is, for example, a mixture obtained after the degassing step, devolatilization is generally carried out under heating, so it is in a warm state and has a low shape retention ability. It is considered that the polymer in the mixture is in a molten state, or the state in which such a mixture is merely shaped (a state in which the shape is given but not solidified), etc. Be Specifically, the mixture to be subjected to the cooling and solidifying step is preferably in the state of 40 ° to 200 ° C., more preferably in the state of 55 ° to 175 ° C., More preferably, it is in the state of 70 to 150 ° C.

The method for cooling and solidifying in the cooling and solidifying step is not limited. For example, a method of cooling and solidifying the mixture by bringing the mixture into contact with a metal plate, a method of cooling and solidifying the mixture directly by applying cold air, or The method of using in combination is preferable.

When the cooling and solidifying step is performed by contacting with a metal plate, the metal plate which can be used is not limited, but, for example, drum cooler 1 (for example, Tsubako Keiichi I made, product name: COMPACT CONTI COOLER Product name: Drum cooler DC; Modern Machinery Co., Ltd. product name: Laminator) Single belt cooler (For example, Sandvik product name: Product name: Steel belt cooler; Nippon Steel Conveyor ( 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) in the cooling device, such as mixture with Metal plate, metal surface capable of touch are preferred. This metal plate · metal surface is the desired temperature It is preferable that the cooling be performed by, for example, blowing a refrigerant from the back side of the metal plate or metal surface.

The cooling temperature of the metal plate is not particularly 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 a temperature lower than the melting point, for example, It is preferable that it is one 25 to 40 T :, 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 solidification. The mixture may be positively cooled by spraying or the like, or may be cooled by leaving, and the cooling means is not limited.), For example, the above mixture can be easily peeled off from the metal plate after cooling and solidification. It is possible to obtain a cooled solidified product with a stable yield.

When the cooling and solidification step is carried out 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 / or a temperature below the melting point. It is preferable that the temperature or the wind speed can be For example, in the case of a sheet (plate) -like mixture (for example, a shape such as 2 mm x 2 5 O mm x 2 5 mm), a cold wind of about 9 ° C may be applied at a wind speed of about 1 mZ seconds, In the case of a block (lump, cylindrical) mixture (for example, a shape having a diameter of 25 mm x 10 O mm), the cold air at a temperature of about 5 to 10 ° C is used at a wind speed of 1 to 1: 1.5 mZ 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, double steel belt cooler 1, single belt cooler, drum cooler 1 and rolling double roll (for example, Kansai Roll Co., Ltd. product name: 8 X 20 BOX type roll machine) are used In the case where it is used, arbitrary production volume conditions can be easily obtained by selection of the cooling belt, the temperature of the refrigerant, the selection of the type of refrigerant, and the width of the T die and the width of the double steel.

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. Holding, cooling with cold air, (ii) casting the mixture in advance into a container or the like for molding, and (iii) metal for cooling and solidifying the mixture as it is And contacting with the plate, and forming into a desired shape (eg, granular, sheet-like, etc.) and the like. As an example of the process of (iii), the mixture is charged into a cylindrical drum having a plurality of holes (desired hole diameter) opened on the side, and this drum is rotated with its central axis (circular axis) horizontal and the holes The process of forming into particles while cooling and solidifying can be mentioned by dropping it 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 block) or rolling two rolls at relatively high temperature (for example, Kansai Roll Co., Ltd. product name: 8 X 20) BOX type It is preferable that the sheet is fed into a roll machine to make a sheet.

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-cleaning type reactor (Mitsubishi Heavy Industries, Ltd.), KRC Reader (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, Low molecular weight polyether compounds, etc.), fillers (carbon etc.), surfactants (ethylene oxide non-ionic surfactants etc.), lubricants (calcium stearate etc.), etc. can be mentioned. 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. Examples of organic fine particles include polystyrene, polyethylene and polypropylene. Fine particles are preferable. As the inorganic fine particles, for example, fine particles such as silica, alumina and zirconia or composite oxides thereof are preferable.

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

In the case of carrying out 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 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 temperature of the mixture to be granulated (in particular, the polymer) be a temperature that can be a crystallization temperature and / or a temperature below the melting point, for example, The temperature is preferably 0 ° 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 fluidity improver, etc. may be mentioned, but among them, an anti-caking agent and a fluidity improver (for example, Nippon Aerosil Co., Ltd., product name: Aerosil R 9 72, Aerosil R 9 4) is preferable. 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 law 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 (sorting 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. As an apparatus which can be used in the sorting process, for example, a vibrating sieve (manufactured by Seishin Enterprise Co., Ltd., product name: Rotex 1 3 0 2 There are various known devices that can sort particles, such as PSSSSL type). It is preferable that the sorting of the particles be performed by direct derivation to the sieve as described above. Before this sorting step, for example, any additive added to the mixture which is not sufficiently attached to the mixture is given vibration (horizontal direction or vertical direction), scraper, brush, etc. It may have a removal step by external force such as contact peeling off or flying with wind power. The sorting step may be performed after the drying step described later.

[Drying process Z 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 it is in the state in which the water content of the mixture already satisfies the desired range described below (specifically, 300 p p m or less), the drying process can be performed. 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 drying is preferably 2 7 00 ppm or less, more preferably 7 0 00 ppm or less, still more preferably 4 7 0 0 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 may be degraded, which may adversely affect battery performance and the like.

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 positive electrode material composition obtained by the production method of the present invention preferably has a water content of 300 ppm or less, more preferably 250 ppm or less, still more preferably 20 O 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. When the water content exceeds 300 ppm, the water content and the lithium salt react with each other during preparation of the positive electrode material, and lithium ion is produced. Since the lithium is consumed as a hydroxide, there is a possibility that the battery performance of the lithium secondary battery may be degraded, for example, the ion conductivity may be degraded.

However, 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 material composition to be supplied to the extruder. It is preferable that the water content in the film is higher to some extent because the plastic effect of water can stably push out the film. In such a case, a humidity control step is provided after the granulation step to control the mixture (positive electrode material composition), and then, for example, a vent for reducing pressure is provided at the tip of an extruder or the like. The water content may be removed just before filming with the extruder etc. by removing the water right before the outlet of the extruder etc., and the water content in the above 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 3, OOO ppm or less, in consideration of the amount of water that can be removed immediately before film formation. It is preferable to

The method of controlling the humidity in the conditioning step is not limited, but, for example, after spraying a predetermined amount of water (preferably ion exchanged water) into the mixture through a mister or spray nozzle etc., for example, the device etc. The mixture and the sprayed water may be made to be compatible by stirring and rotating using.

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 using, for example, a hollow fiber membrane separation type compressed air dryer (manufactured by Toshiba Plant Construction Co., Ltd., product name: MA C D A S S). The compressed air preferably has a dew point of 30 ° C. or less, more preferably a dew point of 40 ° C. or less, and still more preferably a dew point of 50 ° C. or less. If the above compressed air exceeds a dew point of 30 ° C., the moisture 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, with refrigeration dehumidification processing, the compressed air is cooled by a refrigerator, and the moisture in the compressed air is It is a treatment that produces a dry atmosphere by obtaining condensed air by drainage.

Specifically, the adsorbent-type dehumidifying treatment is a treatment in which moisture is adsorbed by an adsorbent such as activated alumina to obtain dry air to create 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.

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. In order to keep the water content of the positive electrode material composition at a low level (for example, 300 ppm or less, preferably 250 ppm or less, more preferably 200 ppm or less), the gas containing the above inert gas Preferably, the gas has a low water content.

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.

The manufacturing method of the present invention is characterized in that the weight average molecular weight of the polymer (here, the polymer before mixing) in the polymer solution used in the mixing step is Mw. When the weight average molecular weight of the polymer in the mixture after the final step (positive electrode material composition) is Mw, the weight average molecular weight reduction rate (D _Mw ) determined by the following formula (1) is 10% or less Is preferred. 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 0 0 (1)

The above D _Mw is more preferably 7% or less, still more preferably 5% or less. If the above-mentioned D _{M w} 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 process means the final process among all the processes performed after the mixing process and the degassing process.

[Positive material composition]

The positive electrode material composition (i.e., the mixture finally obtained) obtained by the production method of the present invention is a material composition that can be used for producing the positive electrode portion of a lithium secondary battery, and is mainly composed of the positive electrode portion. Among the components, the composition is a composition in which a polymer, an electrode active material and a conductive aid are uniformly mixed. Therefore, when the positive electrode portion of a lithium secondary battery is produced using the positive electrode material composition obtained by the production method of the present invention, an electrolytic salt serving as a source of Li + in addition to the composition. (Lithium salt) is contained and used. In addition, the "electrolyte salt" mentioned here may be generally called "supporting electrolyte".

The electrolyte salt is a lithium salt generally used for the positive electrode of a lithium secondary battery. For example, but is not limited to, for example, fluoride ion, chloride ion, bromide ion, iodide ion, heptafluoropropylsulfonate ion, bis (trifluoromethanesulfonyl) ide ion, bis (heptafluoro ion (Propylsulfonyl) imide ion, trifluorosulfonimide ion, tetrafluoroboronate ion, nitrate ion, As F ₆ —, PF ₆ ^_ , stearyl sulfonate ion, octyl sulfonate ion, dodecylbenzene sulfonate ion, naphthalene At least one anion selected from the group consisting of sulfonate ion, dodecyl naphthalene sulfonate ion and 7,7,8,8-tetracyano-p-quinodimethane ion, and lithium ion as cation The salt etc. which consist of L i +) are mentioned preferably, Among them, L i BF ₄ , L i PF ₆ , L i CF ₃ S 0 ₃ , L i C ₄ F ₉ S 0 ₃ , L i N (CF ₃ S 0 ₂ ) ₂ and L i N (C ₂ F ₆ S 0) ₂ ) ₂ is more preferable. The electrolyte salt may be used alone or in combination of two or more.

The mixing ratio of the electrolyte salt is not limited. For example, in the positive electrode material composition obtained by the production method of the present invention, oxygen atoms in the polymer contained in the polymer solution used (for example, in the polyether skeleton) The molar ratio of oxygen atom) to lithium atom in the electrolyte salt (lithium salt) (OZL i) is preferably 1 to 36, more preferably 3 to 33, still more preferably 6 to 6 It is thirty. If the amount of the electrolyte salt is too small, the ion conductivity may be lowered. On the other hand, if the amount of the electrolyte salt is too large, the effect of improving the ion conductivity can not be recognized even if it is added further, and the economy is inferior. May be

The method for incorporating a lithium salt (electrolyte salt) into the positive electrode material composition obtained by the production method of the present invention is not limited, but for example, when used as a film-like positive electrode material, the present invention A method may be adopted in which the positive electrode material composition obtained by the production method of the present invention is introduced into an extruder or the like together with a lithium salt (electrolyte salt) to melt and mix. At this time, the equipment to be fed to the extruder may be appropriately selected and adopted according to the shape of the positive electrode material composition. 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 side of the extruder. Can be quantitatively supplied from a twin screw type screw feeder. In addition, when the shape of the composition is a block (block shape), melters such as hopper discharger type kneaders or kneaders that use uniaxial or biaxial systems or both systems together (( It can be melted by Moriyama Co., Ltd., Product Name: 2TR-50 or 2TR-75), and can be quantitatively supplied to the first supply port on the motor side of the extruder. It is also possible to quantitatively feed the first feed port of the extruder in a molten state and in an unshaped state, such as a mixture containing no or hardly any solvent obtained after the volatilization step.

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% J." Measurement methods and evaluation methods in Examples and Comparative Examples will be described below.

G PC device which made calibration curve using polyethylene oxide standard molecular weight sample Product name: II LC-8120GPC).

Acetate nitrile is added to the polymer solution so that the polymer concentration in the polymer solution becomes 1 wt% and dissolved, and then centrifuged at 2000 rpm for 3 minutes. A predetermined solvent (eluent (acetonitrile / water, anhydrous sodium acetate)) was added to the obtained supernatant to dilute, and then measured.

As for the polymer component in the positive electrode material composition (or mixture), asacetonitrile is added to the composition (or mixture) to make a 1% solution of the composition (or mixture), and the solution is The electrode active material is dispersed by sufficiently stirring with a Tatsumi mixer and shaker to dissolve the polymer component. Thereafter, the mixture was filtered through a filter (non-aqueous, aperture: 45 / zm) to remove insolubles, and the filtrate was diluted by adding 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 Dewatered) to give a 5 to 30 wt% solution of the composition (or mixture), and the solution is stirred with a strong stirrer to sufficiently disperse the electrode active material, Dissolve the polymer component. After that, centrifuge it to settle the main insoluble matter and precipitate the supernatant liquid with syringe for about 2-3mL, and use Karl Fischer moisture measuring instrument (Coulometric titration method, manufactured by Hiranuma Sangyo Co., Ltd., Product name: AQ-7). The amount of water contained in the solution (p pm) was measured (measurement A). Separately, with regard to dehydrated acetonitrile used as a solvent, the water content (p pm) was also measured (measurement B) using the same measuring instrument. The water content by measurement B was subtracted from the water content by measurement A, and the water content (ppm) in the composition (or mixture) was determined.

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) was determined as the weight of the non-volatile component.

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 (residue left on the filter) obtained by the above two vacuum filtrations is dried at 110 ° C. under a vacuum heating of 0.009 to 0.1 OMP a for 1 hour, and the total after drying The weight was measured as the weight of the electrode active material containing the conductive aid. 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 With regard to the filtrate obtained by the above two vacuum filtrations, the content of the polymer component in the positive electrode material composition (or mixture) used for the measurement as the solid content by applying the solid content measurement method described above The percentage (wt%) 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 (Phip-2 manufactured by Philips, Inc. Measure the strength of vanadium in the electrode active material in the form of 404). 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, sampling is performed at several places (2 to 3 places from the jacket side and the central part (near the stirring rod) in the stirring device etc.) The content ratio of the electrode active material containing the auxiliary agent was measured. The fluctuation of each measured value between each sample is evaluated according to the criteria shown in Table 1 below as a factor of evaluation of the dispersion state after mixing, paying attention to the maximum difference between each measured value among each sample. did.

【table 1】

[Example 1]

<< Preparation of polymer solution >>

In a 1 L reactor equipped with Max Blend Wing (Sumitomo Heavy Industries, Ltd.) and an addition port, charge 170 parts of solvent (toluene) and stir at 70 ° C. for 3 hours. After the inside of the reactor was washed, the solvent was removed and the residue was heated and dried, and then the inside of the reactor was purged with nitrogen three times (0.5 MP a) to replace with nitrogen. In this reactor, toluene (water content: 20 ppm or less) 9 4 parts of which dehydration processing was carried out with molecular sieve and 1 part of potassium potassium as a reaction initiator (2 O wt% tetrahydrofuran solution) 1. 7 9 copies were sequentially introduced. After the introduction, the Maxblend blade is rotated at 90 rpm and stirring is performed, while nitrogen substitution in the reactor is performed, nitrogen pressure is applied until the pressure in the reactor reaches 0.3 MP a, and the jacket is heated Flowed to raise the temperature.

After confirming that the internal temperature of the reactor had reached 90 ° C., ethylene oxide was fed at a feed rate of 220.2 parts and fed quantitatively for 40 minutes. Supply start of ethylene oxide After 20 minutes, the supply of butanedioxide denatured by molecular sieve (containing water content: 400 ppm or less) was started at a supply rate of 48.9 parts / h and quantitatively supplied for 20 minutes. Forty minutes after the start of ethylene oxide supply, the solution was supplied quantitatively for 1 hour each at a supply rate of 146.4 parts Zh for ethylene oxide and 32.6 parts for butylene oxide. One hour and 40 minutes after supply start of ethylene oxide, the supply rate of ethylene oxide was 109. 8 parts / h and that of butylene oxide was 24. 48 parts, respectively. 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 ethylene oxide supply, 50.8 parts of ethylene oxide were fed quantitatively at a feed rate of Zh for a further 2.5 hours (supply amount of ethylene oxide: total 733 parts, supply of butylene oxide Amount: 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 supply, aging was carried out by maintaining the temperature at 100 ° C. and 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 wt% was obtained.

<< Mixing process >>

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 baffle). While flowing, add 0.50 parts of an antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) from the observation window, then charge 30 parts of toluene, and further add carbon black as a conductive aid. The electrode active material (US AVE STOR L LC, product name: lithiated vanadium oxide / carbon blend (same as the following)) containing ~ 8wt% is added from the hopper from 23.76 parts did . Thereafter, the hopper and the like were washed with 5.0 parts of toluene, and the inlet was closed. After the washing, the stirring apparatus was operated (inner blade: 75 rpm, outer blade: 29 rpm) under normal temperature and normal pressure, and mixed by stirring for 30 minutes to obtain a slurry. After completion of stirring, 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. .

Twenty-five parts of the polymer solution (10) 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 ). After that, operate the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), adjust the internal temperature to 50.0 ° C (jacket temperature: 5 1. 9 V) under normal pressure, stir and mix for 1 hour, A slurry was obtained. After that, I reduced the number of revolutions of the wings (inner wing: 50 rpm, outer wing: 24 rpm) and kept this condition for a whole day and night with the jacket heating stopped. The temperature of the jacket after one day and night was 29.1 and the internal temperature was 38.6 ° C. Thus, a slurry-like mixture (11) was obtained.

The mixture (11) had a solid content of 42. 82 wt%, a weight average molecular weight of the polymer component Mw of 13,000, and the content ratio of the electrode active material containing the conductive additive was 69.5 wt %, And the evaluation of the dispersion state after mixing was “◎”.

<< Degassing process >>

(Pre-volatilization) In the above stirring device containing the mixture (11), 0.50 57 parts of antioxidant (manufactured by Apico Corporation, product name: Yoshinox BB) was inserted through a viewing window, the viewing window was closed, and a vacuum was applied. It was connected to a pressure reduction line equipped with a pump and the condenser was flushed with cold water at 10 ° C. After that, while operating the stirring device (inner blade: 75 rp _m , outer blade: 29 rpm), the vacuum pump is also operated to gradually reduce the inside of the stirring device to 100 T rr, and the internal temperature is once After making the temperature (jacket temperature: about 80 ° C), control the internal temperature to be in the range of 48 to 60 ° C (jacket temperature: 75 to 79) and the degree of pressure reduction to be in the range of 59 to 7 OTo rr. Operation was carried out while checking the volume or weight of toluene distilled out into the holder tank (target solid content: 65 wt%). After the operation, the solution pressure within stirrer with nitrogen, and a fine pressurized state of 1. 0 k gZcni ^2. Thus, the mixture (12) was obtained.

The mixture (12) had a solid content of 67.4 wt%, a weight average molecular weight M w of the polymer component of 129,000, and a content ratio of the electrode active material containing a conductive additive of 69.9 wt%. It was hot.

(This degassing)

The main body, supply line and outlet line of KRC kneader (made by Kurimoto Soken Co., Ltd.) are replaced with nitrogen, and heated while heating the jacket to 90 ° C while circulating the heat medium of the jacket. 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: l Or pm), open the flush valve connected to the bottom of the stirring device, and operate the Kier pump, After supplying the mixture (12) to the KRC kneader ^ and confirming that the mixture (12) comes out from the outlet of the KRC kneader, the vacuum pump is operated to start reducing the pressure in the KRC kneader and 27 OTo The pressure was reduced to rr, and after confirming that the distillation of toluene was sufficiently stabilized, the degree of pressure was further increased, and the degree of pressure was 215 Torr, and the internal temperature was 87.8 ° C. (jacket temperature: 89.9 ° C.) In a stream of nitrogen, a mixture (13) of rod-like bodies (cylindrical, diameter: 48 mm, length: 300 mm) was obtained from a single tube (diameter: 48 mm) at the outlet of the KRC kneader.

The mixture (13) has a solid content of 95.0 wt%, a weight average molecular weight M w of the polymer component of 129,000, and a content ratio of the electrode active material containing a conductive auxiliary of 69.6 wt%. It was hot.

<< 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 110 ° C. to cool overnight.

Granulation process

The cooled mixture (13) was supplied to a pulverizer (manufactured by Horai, product name: U-480) at a supply rate of 0.58 kgzmin at room temperature and pulverized.

The ground product of the mixture (13) obtained is that, when it passes 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 95.9 wt%, and the weight average molecular weight of the polymer component was Mw of 15,000.

<< Drying process >>

The inside of the conical dryer (Nikko Industry Co., Ltd. product name: vacuum-type tumble dryer) used as a dryer is fully filled with nitrogen or compressed air (dry air) in advance. In addition, the heat medium of the jacket was further heated to 30 ° C., and the inside of the dryer was heated to 28 ° C.

Into this dryer, 43.7 kg of the pulverized product of the mixture (13) 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 below 11 1 Torr (1463 Pa) and that there were no leaks, nitrogen was circulated in the dryer at 5 LZ min. In this state (that is, the state of an internal temperature of 30 ° C., a flow of nitrogen of 5 min and a pressure reduction degree of 1 l To r r (1463 P a) or less), the above ground product was dried by holding for 17 hours or more.

The pulverized product of the mixture (13) obtained by the drying treatment (the positive electrode material composition of the present invention) has a water content of 126 ppm and a solid content of 100 wt%, The weight-average molecular weight Mw of the polymer component was 123,000, the molecular weight distribution (MwZMn) of the polymer component was 1.52, and the content ratio of the electrode active material containing a conductive additive was 69.4 wt%. .

[Example 2]

<< Preparation of polymer solution >>

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

<< Mixing process >>

A small amount of nitrogen is contained in a bowl-shaped concentric twin-screw agitator (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, add 0.50 parts of antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) from the viewing window, and then charge 30 parts of toluene, and further, add a carbon black as a conductive additive. 23. 76 parts of an electrode active material containing 1 to 8 wt% (US AVE STOR L LC, product name: lithium vanadium oxide carbon blend) was charged from the hopper. Thereafter, the hopper and the like were washed with toluene 5.00 part, and the inlet was closed. After the washing, the stirring apparatus was operated (inner blade: 75 rpm, outer blade: 29 rpm) under normal temperature and pressure, and mixed for 30 minutes with stirring to obtain a slurry. After completion of the stirring, the inside of the stirring apparatus was pressurized to 1.6 kgzcm ² with nitrogen and the degassing operation of reducing the pressure to 100 mmH g was repeated several times to remove excess water and dissolved oxygen in the system.

Twenty-five parts of the polymer solution (10), which was previously heated and kept at about 80 ° C., was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ). After that, operate the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), adjust the internal temperature to 49. 1 ° C (jacket temperature: 5 1.6 ° C) under normal pressure, and mix for 1 hour with stirring And I got a slurry. After that, the number of revolutions of both wings was reduced (inner wing: 50 rpm, outer wing: 24 rpm) and this condition was maintained for a whole day and night while heating of the jacket was stopped. The temperature of the jacket after one day and night was 35.9 ° C, and the internal temperature was 36.2 ° C. Thus, a slurry-like mixture (21) was obtained.

The mixture (21) has a solid content of 44.5 wt%, a weight average molecular weight M w of the polymer component of 1 25,000, and a content ratio of the electrode active material containing a conductive additive of 69.5 wt %, And the evaluation of the dispersed state after mixing was “」 ”. -

<< Degassing process >> (Pre-volatilization)

Into the above stirring apparatus containing the mixture (21), 0.50 57 parts of antioxidant (manufactured by Apico Corporation, product name: Yoshinox BB) was inserted through a viewing window, the viewing window was closed, and a vacuum was applied. It was connected to a pressure reduction line equipped with a pump and the condenser was flushed with cold water at 10 ° C. After that, while operating the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), the vacuum pump is also operated to gradually reduce the inside of the stirring device to 10 OTo rr, and the internal temperature is 53 ° C (jacket temperature: approx. 80 ° C), then the internal temperature is 47 to 49 (jacket temperature: 75 to 79 T :), and the pressure reduction is controlled to fall within the range of 60 to 69 Torr. Operation was carried out while checking the volume or weight of toluene distilled to (target solid content: 65 wt%). After the operation, the inside of the stirring apparatus was depressurized by nitrogen to a slight pressure of 1.0 kgzcm ² . Thus, the mixture (22) was obtained.

The mixture (22) has a solid content of 67.4 wt%, a weight average molecular weight of one polymer component M w is 120,000, and a content ratio of an electrode active material containing a conductive auxiliary is 69.9 wt% It was.

(This degassing)

The main body, supply line and outlet line of KRC Nidar (made by Kurimoto Co., Ltd.) are replaced with nitrogen, heated to 90 ° C. while circulating the heat medium of the jacket, and the outlet of KRC kneader After the steam was sent to the steam trace of the piping and warmed up, the KRC 21-hour screen was operated at 38 rpm. After that, operate the above-mentioned stirring device containing the mixture (22) (inner blade: stop, outer blade: l Or pm), open the flush valve connected to the bottom of the stirring device, and operate the Kier pump, The mixture (22) was supplied to the KRC kneader ^ ·, and it was confirmed that the mixture (22) came out from the outlet of the KRC kneader. Thereafter, the vacuum pump is operated to start reducing the pressure in the KRC kneader, and the pressure is reduced to 270 Torr. After confirming that the distillation of toluene is sufficiently stabilized, the degree of pressure reduction is further increased, and the degree of pressure reduction is 267 Tor. rr, The melt mixture (22) coming out from the outlet of the KRC kneader at an internal temperature of 88. 8 ° C (jacket temperature: 90. 1 ° C) through a gear pump, Strand die (diameter A mixture (23) of strings (strings, diameter: 3.3 mm, length: 10 to 50 m) was obtained from a 2 mm × 2 hole) under a nitrogen stream.

The mixture (23) has a solid content of 85. 1 wt%, a weight average molecular weight of the polymer component M w is 12.5 000, and the content ratio of the electrode active material containing the conductive additive is 69.6 wt% It was. ,

<< Cooling and Solidification Process >>

First, the mixture (23) obtained after this volatilization is placed on a belt conveyor (manufactured by Sanei Seisakusho Co., Ltd., product name: SINCEICONBA SJY-15-200N), room temperature (22. C), nitrogen gas After flowing down, the surface of the mixture of strings (23) is dried, and then placed on a single belt cooler (manufactured by Nippon Steel Conveyor Co., Ltd., product name: steel belt single cooler) and cooled with cooling water. Contact the metal surface of the ° C under nitrogen atmosphere and cool the inside of the mixture of strands (23).

The mixture of strings (23) thus obtained is put together, put into an aluminum laminate bag, and thoroughly dried overnight under a nitrogen atmosphere.

Granulation process> The mixture (23) after cooling is supplied to a strand cutter (made by Izu Chemical Co., Ltd., product name: S FC-100) at a supply rate of about 1 Om / min at room temperature, and cut, and then rounded. A pellet-like (cylindrical) mixture was obtained.

The resulting round pellet-like mixture had a diameter of 3.3 mm, and the thickness (height) was such that 70% or more of the whole on the number basis satisfied the range of 3.65 ± 0.5 mm, 1 The average weight of the particles was 49.7 mg, the water content was 2060 ppm, the solid content was 96.0 wt%, and the weight average molecular weight of one polymer component was 123,000.

<< 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 30.degree. C. and the inside of the dryer was heated to 28.degree.

Into this dryer, 43.7 kg of the round pellet-like mixture 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 less than 1 1 Torr (1463 Pa) and that there was no leak, nitrogen was circulated in the dryer at 5 LZ min. In this state (that is, the state where the internal temperature is 30 ° C., the flow of nitrogen 5 L_min and the degree of reduced pressure 1 1 Torr or less (1463 P a) or less), the above round pellet-like mixture is dried The

The mixture in the form of a round pellet (the positive electrode material composition of the present invention) obtained by the drying treatment as described above has a water content of 84 ppm and a solid content of 100 wt%. The weight average molecular weight Mw was 12.2 000, the molecular weight distribution (MwZMn) of the polymer component was 1.51, and the content ratio of the electrode active material containing the conductive additive was 71.0 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 one polymer component is 120,000 and the solid content is 45.8 wt%.

<< Mixing process >>

A small amount of nitrogen is contained in a bowl-shaped concentric twin-screw agitator (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 pouring, Add 0. 095 parts of an antioxidant (product name: Yoshinox BB, manufactured by AP Corporation) through the viewing window, then charge 1. 6 parts of toluene 2 and further add power as a conductive aid An electrode active material containing 1 to 8 wt% of carbon black (US AV E STOR L LC, product name: lithium vanadium oxide carbon blend) 39.6 parts were charged from the hopper. Thereafter, the hopper and the like were washed with toluene (9.0 parts), and the inlet was closed. After the washing, the stirring device was operated (inner blade: 75 rpm, outer blade: 29 rpm) under normal temperature and normal pressure, and mixed for 30 minutes with stirring to obtain a slurry. After completion of 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 is repeated several times to remove excess water and dissolved oxygen in the system. The

The polymer solution (10) 4 1. 63 parts previously warmed to approximately 80 ° C. 0.5 kg / cm ² ) was charged to the agitator. After that, operate the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), adjust the internal temperature to 49.2 ° C (jacket temperature: 48.4 ° C) under normal pressure, and stir for 2 hours Mix to obtain a slurry. After that, the number of turns of the wings remained unchanged, and heating of the jacket was stopped, and this state was maintained overnight. The temperature of the jacket after one day and night was 17.8 ° C, and the internal temperature was 45.1 ° C. Thus, a slurry-like mixture (31) was obtained.

The mixture (31) has a solids content of 52.7 wt%, a weight average molecular weight Mw of the polymer component of 124,000, and a content ratio of the electrode active material containing a conductive additive of 68.6 wt%. The evaluation of the dispersed state after mixing was “◎”.

<< Degassing process >>

(Pre-volatilization)

Into the above stirring device containing mixture (31), 0.50 57 parts of antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) was inserted through a viewing window, the viewing window was closed, and a vacuum pump was used. The condenser was flushed with cold water at 10 ° C. 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 10 OTo rr, and the internal temperature is 53 After setting the temperature to 70 ° C (jacket temperature: approx. 80 ° C), the internal temperature is controlled to 60.7 ° C (jacket temperature: 60.9 ° C), and the degree of pressure reduction to be in the range of 59-70 Torr. Operation was carried out while checking the volume or weight of the toluene distilled into the holder tank (target solid content: 65 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 (32) was obtained.

The mixture (32) has a solid content of 66.5 wt%, a weight average molecular weight M w of the polymer component of 123,000, and a content ratio of the electrode active material containing a conductive additive of 69.3 wt% It was hot.

(This degassing)

The main body, supply line and outlet line of KRC kneader (made by Kurimoto Soto Co., Ltd.) are replaced with nitrogen, and heated while heating medium at 90 ° C while circulating the heat medium of the jacket. After steaming and warming the steam trace of the KRC, the KRC Knida Ichi's screen 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 27 OTo rr After reducing the pressure to a low pressure and confirming that the distillation of toluene is sufficiently stable, increase the degree of pressure further, the degree of pressure is 150 Torr, and the internal temperature is 87.6 ° C (jacket temperature: 89. 9 ° C) A mixture (33) of rod-like bodies (cylindrical, diameter: 48 mm, length: 300 mm) was obtained from a single tube (diameter: 48 mm) at the outlet of the KRC kneader under nitrogen stream (KRC kneader Discharge rate from the outlet single pipe: 5. 60-6. 12k g / h).

The mixture (33) has a solid content of 98.4 wt%, a weight average molecular weight of the polymer component M w of 123,000, and a content ratio of the electrode active material containing a conductive additive of 69.6 wt%. It was%. << Cooling and Solidification Process >>

The mixture (33) obtained after this volatilization is heated to about 90 ° C., and then rolled double roll (Kansai Roll Co., Ltd., product name: 8 X 20 BOX type slot machine, front roll Temperature: 20. 2 ° C, After roll temperature: 21.3 C, guide width: 55 mm, rotation speed: 2. 4 rpm), thickness 2.1 mm, width 83 mm, length 2920 mm sheet I made it. The temperature of this sheet was 45.degree.

The sheeted mixture (33) was placed in an aluminum laminate bag, sufficiently purged with nitrogen, sealed with a heat seal, and allowed to cool at room temperature overnight.

Granulation process>

The obtained sheet is fed at a feed rate of 1.6 mZh to a sheet cutter (product name: SGE-220 type, manufactured by Horai Co., Ltd.) at a temperature of 20 ° C. or less, and the number of rotation of the vertical blade 1 6. 4 Hz Cutting was performed at a horizontal blade rotational speed of 20.3 Hz to obtain a square pellet-like mixture.

The resulting angular pellet-like mixture is 2.0 mm thick and 4.1 mm wide, and the length is 90% of the whole based on the number basis and satisfies the range of 4.1 ± 0.5 mm. The average weight of one tablet was 55 mg, the water content was 1 900 ppm, the solid content was 99.0 wt%, and the weight average molecular weight Mw of the polymer component was 124,000.

<< Drying process >>

Into this dryer, 43.7 kg of square pellet-like mixture was put from the inlet of the dryer, and it was sufficiently 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 less than 1 1 Torr (1463 Pa) and that there was no leak, nitrogen was circulated in the dryer at 5 LZ min. In this state (that is, the state where the internal temperature is 30 ° C., the flow of nitrogen 5 LZ min and the degree of pressure reduction 1 1 Torr or less (1463 Pa) or less), the mixture is held for 12 hours or more. I did.

The rectangular pellet-like mixture (the positive electrode material composition of the present invention) obtained by the drying treatment as described above has a water content of 110 ppm and a solid content of 100 wt%. The weight average molecular weight Mw of the polymer component is 123,000, the molecular weight distribution (Mw / Mn) of the polymer component is 1.54, and the content ratio of the electrode active material containing the conductive additive is 69.3 wt%. there were.

[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 component is 120,000 and the solid content is 45.8 wt%.

<< Mixing process >>

Antioxidant (AIP Corporation manufactured by AIP Corp., Product name: Yoshinox) while flowing a small amount of nitrogen to a stirring device equipped with a helical ribbon blade (Shin Steel Environmental Solution, product name: Double helical ribbon blade) BB) After inserting 0. 095 part into the viewing window, 21. Charge 6 parts, and further add 1 to 8 wt% of carbon black as conductive aid (US AVE STOR LLC's product name: product: Vitanic oxide lithium oxide blend) 39.6 Parts were loaded from the hopper. Thereafter, the hopper and the like were washed with 9.0 parts of toluene, and the inlet was closed. After the washing, the stirrer was operated (29 rpm) under normal temperature and pressure, and mixed for 30 minutes with stirring to obtain a slurry. After completion of stirring, the inside of the stirring apparatus was pressurized to 1.6 kgzcm ² with nitrogen and depressurization to 10 O mmHg was repeated several times to remove excess water and dissolved oxygen in the system.

41. 63 parts of the polymer solution (10) which had been preheated and kept at about 80 ° C. was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ). Then, the stirrer was operated (29 rpm), the internal temperature was 49.7 ° C. (jacket temperature: 50.3 ° C.) under normal pressure, and the mixture was stirred for 2 hours to obtain a slurry. After that, the speed of both wings remained as it was, and with the heating of the jacket stopped, this condition was maintained for a whole day and night. The temperature of the jacket after one day and night was 33.0 ° C, and the internal temperature was 34.2 ° C. Thus, a slurry-like mixture (41) was obtained.

The mixture (41) has a solid content of 53. O t t%, a weight average molecular weight M w of the polymer component of 124,000, and the content ratio of the electrode active material containing the conductive auxiliary is 68.3 wt%. The evaluation of the dispersed state after mixing was “◎”.

<< Degassing process >>

(Pre-volatilization)

Into the above stirring device containing mixture (41), 0.50 57 parts of antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) was inserted through a viewing window, the viewing window was closed, and a vacuum pump The condenser was flushed with cold water at 10 ° C. After that, while operating the stirring device (29 rpm), the vacuum pump is also operated to gradually reduce the inside of the stirring device to 1 O O O rr, and the internal temperature is 53 ° C (jacket temperature: about 80) After the internal temperature is adjusted to 64. 7 ° C (jacket temperature: 59.3 ° C), the degree of pressure reduction is controlled to fall within the range of 60 to 70 Torr, and it is distilled out into the holder tank. Operation was carried out while confirming the volume or weight of toluene (target solid content: 65 wt%). After the operation, the inside of the stirring device was Kai圧by nitrogen and the slight pressure state of 1. 0 k gZcm ^2. Thus, a mixture (42) was obtained.

The mixture (42) has a solid content of 68.7 wt%, a weight average molecular weight of the polymer component M w of 124,000, and the content ratio of the electrode active material containing the conductive additive is 68.3 wt%. It was hot.

(This degassing)

The main body, supply line and outlet line of KRC kneader (made by Kurimoto Soken Co., Ltd.) are replaced with nitrogen, and heated while heating the jacket to 90 ° C while circulating the heat medium of the jacket. After the steam was poured into the trace and warmed up, the screw of the KRC kneader was operated at 38 rpm. After that, the above mixing device containing the mixture (42) is operated (inner wing: stop, outer wing

Open the flush valve connected to the bottom of the stirrer, activate the pump and supply the mixture (42) to the KRC duplexer, from the outlet of the KRC kneader

After confirming that (42) comes out, operate the vacuum pump and start reducing the pressure in the KRC kneader to reduce the pressure to 270 Torr, and after confirming that the distillation of toluene is sufficiently stabilized, Increase the degree of pressure reduction, the pressure degree is 15 OTo rr, the internal temperature is 97. I (jacket temperature: 1 A mixture of rod-like bodies (cylindrical, diameter: 48 mm, length: 300 mm) from a single tube (diameter: 48 mm) at the outlet of the KRC kneader at 00. 0 ° C) (43) (Discharge rate from a single tube at the outlet of KRC: about 6.0 kg Zh).

The mixture (43) has a solid content of 96. lwt%, a weight average molecular weight Mw of the polymer component is 120,000, and the content ratio of the electrode active material containing the conductive additive is 68.3 wt%. It was hot.

Solidification and cooling process

The mixture (43) obtained after this volatilization is heated to about 90 ° C., and then the rolling double roll (Kansai Roll Co., Ltd., product name: 8 X 20 BOX type roll machine, temperature of front roll) : 20. 2 ° C, temperature of roll: 21.3 ° C, guide width: 55 mm, rotation speed: 2. 4 rpm), thickness 2.1 mm, width 83 mm, length 2920 mm sheet I made it. The temperature of this sheet was 45 3⁄4.

The sheeted mixture (43) 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 introduced into a sheet cutter (manufactured by Horai Co., Ltd., product name: 30 £-220 type) at a supply speed of 1.6 mZh at a temperature of 20 ° C. or less, and the number of rotation of the vertical blade 1 6. The mixture was cut at 4 Hz with a 20.3 Hz blade speed to obtain a square pellet-like mixture.

The resulting angular pellet-like mixture is 2.0 mm thick and 4.1 mm wide, and the length is 90% of the whole based on the number basis and satisfies the range of 4.1 ± 0.5 mm. The average weight of one tablet was 51.5 mg, the water content was 1 950 ppm, the solid content was 98.0 wt%, and the weight average molecular weight Mw of the polymer component was 123,000 .

<< Drying process >>

The inside of the conical dryer (Nikko Industry Co., Ltd. product name: vacuum-type tumble dryer) used as a dryer is fully replaced with nitrogen or compressed air (dry air) in advance, and the jacket is heated further. The medium was heated to 30.degree. C. and the inside of the dryer was heated to 28.degree.

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 less than 1 1 Torr (1463 Pa) and that there was no leak, nitrogen was circulated in the dryer at 5 LZ min. In this state (that is, the state where the internal temperature is 30 ° C., the flow of nitrogen 5 LZ min and the pressure reduction degree 1 1 Torr or less (1463 Pa) or less), the mixture is held for 12 hours or longer to dry the above angular pellet-like mixture I did.

The rectangular pellet-like mixture (the 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%. The weight average molecular weight Mw was 12.2 000, the molecular weight distribution (MwZMn) of the polymer component was 1.45, and the content ratio of the electrode active material containing the conductive additive was 68.4 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 component is 124,000 and the solid content is 45.8 wt%.

<< Mixing process >>

30.0 parts of toluene and about 80 ° C in advance while flowing a small amount of nitrogen to a vertical mixing agitator equipped with Max Blend wings (Product name: Max Blend wings, manufactured by Sumitomo Heavy Industries, Ltd.) 2. 5 parts of the polymer solution (10) warmed and kept warm was charged, the inlet was closed, and the stirrer was operated (100 rpm) under normal temperature and pressure, and mixed for 30 minutes with stirring. After that, the stirring is stopped, nitrogen is flowed, and 0.50 parts of an antioxidant (product name: Yoshinox BB) manufactured by AP corporation, is inserted from the observation window, and carbon black as a conductive aid is further added. To! 23. 76 parts of an electrode active material (manufactured by US AVE STOR LLC, product name: lithium vanadium oxide carbon blend) containing ~ 8 wt% was charged from a hopper. Thereafter, the hopper and the like were washed with 5.0 parts of toluene, and the inlet was closed. After the washing, the stirring device was operated (100 rpm) under normal temperature and normal pressure, and mixed for 30 minutes with stirring to obtain a slurry. After completion of stirring, the pressure inside the stirring apparatus was increased to 1.6 kg / cm ² with nitrogen and the degassing operation of reducing the pressure to 100 mm Hg was repeated several times to remove excess water and dissolved oxygen in the system. 22. 50 parts of the polymer solution (10) kept warm at 80 ° C. was charged into a stirrer by nitrogen pressure (0.5 kg z cm ² ). Then, the stirrer was operated (100 rpm), the internal temperature was adjusted to 48.6 ° C. (jacket temperature: 50.0 ° C.) under normal pressure, and the mixture was stirred for 2 hours to obtain a slurry. After that, the speed of both wings remained unchanged, and the heating of the jacket was stopped, and this state was maintained for a whole day and night. The temperature of the jacket after one day was 32 ° C, and the internal temperature was 30.1 ° C. Thus, a slurry-like mixture (51) was obtained. The mixture (51) had a solid content of 42. 1 wt%, a weight average molecular weight M of the polymer component of 124,000, and a content ratio of the electrode active material containing a conductive additive was 68.5 wt%. The evaluation of the dispersion state after mixing was “◎”.

Degassing process

Mixture (51) was added to the above stirring device, and after 0.55 parts of antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) was inserted through a viewing window, the viewing window was closed and a vacuum pump was used. The condenser was flushed with cold water at 10 ° C. After that, while operating the stirring device (100 rpm), the vacuum pump is also operated and the inside of the stirring device is gradually depressurized to 10 O rr, and the internal temperature is 53 ° C (jacket temperature: about 80 ° C After that, the internal temperature is controlled to 50 ° C (jacket temperature: 80 ° C), and the degree of vacuum falls within the range of 60 to 7 OTo rr, and the volume or weight of toluene distilled into the holder tank Operation (target solid content: 65 wt%) while confirming the 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 (52) was obtained.

The obtained mixture (52) (the positive electrode material composition of the present invention) has a solid content of 63.9 wt%, a weight average molecular weight Mw of the polymer component is 124,000, and an electrode containing a conductive auxiliary The content of active material was 68.5 wt%.

[Example 6]

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 component is 120,000 and the solid content is 45.8 wt%.

<< Mixing process >>

In the same manner as in Example 4, the solid content is 53.0 wt%, the weight average molecular weight of the polymer component is 1,200, and the content ratio of the electrode active material containing a conductive auxiliary is 68.3. A slurry-like mixture (61) which is wt% was obtained.

Vacuum 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 1st, 2nd and 3rd vents, 4th Heat the vent, fifth vent, head and die to 90 °.

The inside of the stirring device containing the slurry-like mixture (61) in the above mixing step was pressurized to 0.05MPa with nitrogen, and a gear pump was installed between the stirring device and the first vent of the twin screw extruder. After filling the mixture (6 1) until just before the first vent, rotate the 2nd shaft at low speed, start supplying the mixture (6 1), and increase the rotation speed of 2nd shaft to 100 rpm. It was confirmed that the mixture (61) came out of the biaxial die. After that, start the vacuum pump, decompress the second vent to 449 Torr, and reduce the third vent to 105 Torr, and discharge 6 kg / h from a biaxial die into a rod (cylindrical, diameter: 25 mm) mixture (63) was obtained.

The mixture (63) has a solid content of 98.8 to 99.1 wt%, a weight average molecular weight of the polymer component has a molecular weight Mw of 120,000, and the content ratio of the electrode active material containing a conductive auxiliary is 68. It was 5 wt%. '

<< Cooling and Solidification Process >>

The mixture (63) obtained after this volatilization is heated to about 90 ° C., and then the rolling double roll (Kansai Roll Co., Ltd. product name: Product name: 8 X 20 BOX type roll machine, temperature of front roll) : 20. 2 ° C, temperature of rear roll: 21.3 ° C, guide width: 55 mm, rotation speed: 2.4 rpm), thickness 2. lmm, width 83 mm, length 292 ° mm sheet I made it. The temperature of this sheet was 45.degree.

The sheeted mixture (63) 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 introduced into a sheet cutter (manufactured by Horai Co., Ltd., product name: SGE-220 type) at a supply speed of 1.6 kgzh at a temperature of 20 ° C. or less, and the number of rotation of the vertical blade is 1 6 The mixture was cut at 4 Hz and a horizontal blade speed of 20.3 Hz to obtain a square pellet-like mixture.

The resulting mixture in the form of a square pellet is 2.0 mm thick and 4.1 mm wide, and the length is 90% of the whole based on the number basis, and it satisfies the range of 4.1 ± 0.5 mm, 1 The particles had an average weight of 51.5 mg, a water content of 2050 ppm, a solid content of 99.0 wt%, and a weight average molecular weight of one polymer component, and a Mw of 125,000.

<< Drying process >>

The inside of the conical dryer I (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 further The heat medium is heated to 30 ° C and the inside of the dryer is heated to 28 ° C. I've done it.

Into this dryer, 43.7 kg of square pellet-like mixture was put from the inlet of the dryer, and tightly closed with a port.

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 below 11 Torr (1463 Pa) and that there was no leak, nitrogen was circulated in the dryer at 5 Lzmin. In this state (that is, a state where the internal temperature is 30 ° C., the flow of nitrogen 5 L min and the degree of reduced pressure 11 Torr or less (1463 P a) or less), the mixture is held for 12 hours or more .

The rectangular pellet-like mixture (the positive electrode material composition of the present invention) obtained by the drying treatment as described above has a water content of 150 ppm, a solid content of 100 wt%, and the weight of the polymer component The average molecular weight Mw was 122,000, the molecular weight distribution (MwZMn) of the polymer component was 1.45, and the content ratio of the electrode active material containing a conductive additive was 68.4 wt%.

[Example 7]

<< 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 component is 124,000, and the solid content is 45.8 wt%.

<< Mixing process >>

Nitrogen is added to a vertical twin screw system (product name: Super One 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, add 0. 095 parts of an antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) from the viewing window, and then charge 21.6 parts of toluene. Furthermore, carbon black as a conductive aid 39.6 parts of an electrode active material containing 1 to 8 wt% (US AV ESTOR LLC, product name: lithiated vanadium oxide carbon blend) was charged from the hopper. Thereafter, the hopper and the like were washed with toluene (9.0 parts), and the inlet was closed. After the washing, with the inner wing stopped at normal temperature and pressure, only the outer wing was operated (29 rm), and stirring was carried out for 30 minutes 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.

41. 63 parts of the polymer solution (10) which had been preheated and kept at about 80 was charged into a stirrer by nitrogen pressure (0.5 kg / cm ² ). After that, with the inner wing stopped, operate only the outer wing (29 rpm), set the internal temperature to 50.8 ° C (jacket temperature: 51.8 ° C) under normal pressure, and stir and mix for 2 hours, A slurry was obtained. After that, the speed of both wings remained unchanged, and heating of jacket was stopped, and this state was maintained overnight. The temperature of the jacket after one day and night was 33.0 ° C, and the internal temperature was 40.9 ° C. Thus, a slurry-like mixture (71) was obtained.

The obtained mixture (71) (the positive electrode material composition of the present invention) has a solid content of 52.7 wt%, a weight average molecular weight Mw of the polymer component is 120,000, and an electrode containing a conductive auxiliary The content of the active material was 69.4 wt%, and the evaluation of the dispersed state after mixing was “◎”.

[Example 8]

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

<< Mixing process >>

In the same manner as in Example 4, the solid content is 53. Ow t%, the weight average molecular weight Mw of the polymer component is 120,000, and the content ratio of the electrode active material containing a conductive additive is 68.3. A slurry-like mixture (81) which is wt% was obtained.

Vacuum degassing process

(Pre-volatilization)

In the same manner as in Example 4, the prevolatilization was carried out, and the solid content was 68.7 wt%, the weight average molecular weight Mw of the polymer component was 12.4 000, and the electrode active material containing a conductive aid The mixture (82) was obtained with a content ratio of 68.3 wt%.

(This degassing)

The volatilization is carried out in the same manner as in Example 4. The solid content is 96. 1 wt%, the weight-average molecular weight of the polymer component is Mw is 120,000, and the content ratio of the electrode active material containing a conductive aid The mixture (83) was obtained at 68. 3 wt% (discharge rate from the single tube at the outlet of the KRC kneader: approx. 6 kg / h).

<< Cooling and Solidification Process >>

The mixture (83) obtained after this volatilization is heated to about 90 ° C., and then a rolling double roll (Kansai Shalet Co., Ltd. product name: Product name: 8 X 20 BOX type roll machine, front roll Temperature: 20. 2 ° C, After roll temperature: 21.3 ° C, Guide width: 55 mm, Rotation speed: 2. 4 rpm), Thickness 2.1 mm, Width 83 mm, Length 2920 mm sheet I made it. The temperature of this sheet was 45.degree.

Next, cold air (air, temperature: 9, wind speed: lmZs) was applied to the sheet in a duct to cool the sheet to a temperature of 20 ° C.

Granulation process.

Supply the cooled sheet to a sheet cutter (Horai Co., Ltd. product name: SGE-220 type) at a temperature of 20 ° C or less, and feed it at 1. Sk-gZh, and the vertical blade rotation speed 1 6 The mixture was cut at 4 Hz and a horizontal blade speed of 20.3 Hz to obtain a square pellet-like mixture.

The obtained angular pellet-like mixture had a thickness of 2.0 mm and a width of 4.1 mm, and the length was 90% of the whole based on the number basis, and the range of 4.1 ± 0.5 mm was satisfied. The average weight of one tablet was 51.5 mg, the water content was 1 950 ppm, the solid content was 98.0 wt%, and the weight average molecular weight Mw of the polymer component was 123,000.

<< Drying process >>

Into this dryer, 43.7 kg of square pellet-like mixture was introduced from the inlet of the dryer, and the mixture was sufficiently rolled and sealed with a bolt.

Next, the valve was checked for opening and closing, and the inside of the dryer was depressurized with a vacuum pump. Decompression degree is 1 1 After confirming that there was no leakage after stabilizing at Torr (1 63 Pa), nitrogen was circulated at 5 Lzmin through the dryer. In this state (that is, the state where the internal temperature is 30 ° C., the flow of nitrogen 5 L / min, and the pressure reduction degree is 1 1 Torr or less (1463 Pa) or less), the mixture is held for 12 hours or more. I did.

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, a solid content of 100 wt%, and the weight of the trimer component. The average molecular weight Mw was 122, 000, the molecular weight distribution (Mw / Mn) of the polymer component was 1.45, and the content ratio of the electrode active material containing the conductive auxiliary was 68.4 wt%.

[Example 9]

<< Preparation of polymer solution >>

<< Mixing process >>

In the same manner as in Example 4, the solid content is 53.0 wt%, the weight average molecular weight of the polymer component is 1 ^ ¥¥, and the content ratio of the electrode active material containing a conductive auxiliary is A slurry-like mixture (91) of 68. 3 wt% was obtained.

<< Degassing process >>

Turn on the heater 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, 4th Heat the bent, 5th vent, head and die (strand die, <i) 2mm x 4 holes to 90 °.

The inside of the stirring device containing the slurry-like mixture (91) 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 (91) just before the first vent, rotate the two shafts at low speed, start supplying the mixture (91), and increase the rotation speed of the two shafts to 100 rpm. It was confirmed that the mixture (91) came out of the biaxial die. After that, the vacuum pump was started, the second vent was reduced to 449 Torr, and the third vent was reduced to 105 Torr, and a string of 6 kg gh was discharged from the biaxial die (string,,, A mixture (93) of diameter: 3 mm) was obtained. The mixture (93) has a solid content of 99.1 \ ^ 1%, a weight average molecular weight Mw of the polymer component is 120,000, and the content ratio of the electrode active material containing the conductive additive is 68.5. It was wt%.

Granulation process

A die hot cutter type side cutter of the twin-screw extruder is installed, and the mixture (93) of rod-like bodies at 90-1 10 discharged from the die of the twin-screw extruder is cut immediately after the discharge. A cold air (air, 9 ° C.) was applied to the mixture (93) after the cutting with a spot cooler to sufficiently cool the surface thereof to obtain a mixture of round pellets (columnar).

The resulting round pellet-like mixture has a diameter of 3.3 mm, and the thickness (height) is such that 70% or more of the whole satisfies the range of 3.5 ± 0.5 mm on a number basis. The average weight of one tablet was 49.7 mg, the water content was 2060 ppm, the solid content was 99.0 wt%, and the weight average molecular weight Mw of the polymer component was 123,000. << Drying process >>

The inside of the conical dryer I (Nikko Industry Co., Ltd. product name: Vacuum Mutable 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 30 ° C., and the inside of the dryer was heated to 28 ° C.

Into this dryer, 20 kg of the mixture in the form of a round pellet was put 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 below 11 Torr (1463 Pa) and that there was no leak, nitrogen was circulated in the dryer at 5 Lzmin. In this state (that is, the state where the internal temperature is 30 ° C., the flow of nitrogen 5 m in and the degree of reduced pressure 11 Torr or less (1463 P a) or less), the above mixture of round pellets is dried for 17 hours or more.

The pellet-like mixture (the positive electrode material composition of the present invention) obtained by the drying treatment as described above has a water content of 150 ppm, a solid content of 100 wt%, and a weight average of polymer components The molecular weight Mw was 122,000, the molecular weight distribution (MwZMn) of the polymer component was 1.45, and the content of the electrode active material containing a conductive additive was 68.4 wt%.

[Example 10]

<< 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 component is 124,000 and the solid content is 45.8 wt%.

<< Mixing process >>

Antioxidant (A.P.I.CO.I.POR., Manufactured by A.P.I., Inc.), while flowing a small amount of nitrogen to a vertical mixing agitator equipped with Max Blend wings (Product name: Max Blend Wing, manufactured by Sumitomo Heavy Industries, Ltd.) Name: Yoshinox BB) After 0. 095 parts are inserted through the viewing window, 21. 6 parts of Toruen are charged, and further, an electrode active material containing 1 to 8 wt% of carbon black as a conductive aid (US AVE STOR Made by LLC, Product name: 36.0 parts of lithium vanadium oxide / carbon blend was charged from the hopper. Thereafter, the hopper and the like were washed with 9.0 parts of toluene, and the inlet was closed. After the washing, operate the stirring device under normal temperature and pressure (7

The mixture was stirred and mixed for 60 minutes to obtain a slurry. After completion of the stirring, the volatilization 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.

The polymer solution (10) 41. 63 parts preheated to approximately 80 ° C.

0.5 kg / cm ² ) was charged to the agitator. Then, the stirrer was operated (75 rpm), the internal temperature was adjusted to 49.0 ° C. (jacket temperature: 50.8 ° C.) under normal pressure, and the mixture was stirred for 4 hours to obtain a slurry. After that, the speed of both wings remained as it was, and with the heating of the jacket stopped, this condition was maintained for a whole day and night. The temperature of the jacket after one day and night was 21.8 ° C, and the internal temperature was 37.1 ° C. Thus, a slurry-like mixture (101) was obtained.

The obtained mixture (101) (the positive electrode material composition of the present invention) had a solid content of 48.2 wt%, a weight average molecular weight of the polymer component was 124,000, and an electrode active containing a conductive auxiliary agent. The content ratio of the substance was 68.6 wt%, and the evaluation of the dispersed state after mixing was “△”. [Example 11] '

<< Preparation of Polymer Solution >> In the same manner as in Example 1, a polymer solution (10) having a weight-average molecular weight Mw of 124,000 and a solid content of 45.8 wt% was obtained.

Mix mixing process

A small amount of nitrogen is contained in a bowl-shaped concentric twin-screw agitator (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 pouring, Add 0. 095 parts of an antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) from the viewing window, and then charge 21.6 parts of toluene, and further add carbon black as a conductive aid 39.6 parts of an electrode active material containing 1 to 8 wt% (US AV ESTOR LC, product name: lithium vanadium oxide Z carbon blend) was charged from the hopper. After that, the hopper and the like were washed with 9.0 parts of toluene, and the inlet was closed. After the washing, the stirring device was operated (inner blade: 75 rpm, outer blade: 29 rpm) under normal temperature and normal pressure, and mixed by stirring for 60 minutes to obtain a slurry. After completion of the stirring, the volatilization 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.

41. 63 parts of the polymer solution (10) which had been preheated and kept at about 80 ° C. was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ). After that, operate the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), adjust the internal temperature to 49.2 ° C (jacket temperature: 48.4 ° C) under normal pressure, and stir for 2 hours Mix to obtain a slurry. After that, the rotation speed of both wings remained as it was, and this condition was maintained for a whole day and night while the heating of the jacket was stopped. The temperature of the jacket after one day and night was 17.8 ° C, and the internal temperature was 45.1 ° C. Thus, a slurry-like mixture (111) was obtained.

The mixture (111) had a solids content of 52.7 wt%, a weight average molecular weight of one polymer component, a Mw of 14,000, and a content ratio of the electrode active material containing a conductive additive of 68.6 wt% At that time.

Degassing process

(Pre-volatilization)

In the above stirring device containing the mixture (111), 0.95 parts of antioxidant (manufactured by AP Corporation, product name: Yoshinox BB) was inserted through a viewing window, and then the viewing window was closed and a vacuum was applied. It was connected to a pressure reduction line equipped with a pump and the condenser was flushed with cold water at 10 ° C. After that, while operating the stirring device (inner blade: 75 rpm, outer blade: 29 rpm), the vacuum pump is also operated, the inside of the stirring device is gradually reduced to 10 OTorr, and the internal temperature is temporarily raised to 53 ° C ( After the jacket temperature is about 80 ° C, the internal temperature is controlled to 60.7 ° C (jacket temperature: 60.9 ° C), and the degree of decompression is controlled to fall within the range of 59 to 70 Torr. Operation was carried out while checking the volume or weight of toluene distilled inside (target solid content: 65 wt%). After the operation, the inside of the stirring apparatus was depressurized with nitrogen to a slight pressure of 1.0 kgzcm ² . Thus, a mixture (112) was obtained.

Mixture (112) has a solid content of 66.5 wt%, a weight average molecular weight of polymer component Mw of 123,000, and a content ratio of an electrode active material containing a conductive additive of 69.3 wt% there were

))

The main body, supply line and outlet line of KRC Kneader (made by Kurimoto Soto Co., Ltd.) are replaced with nitrogen, and heated to 90 ° C while circulating the heat medium of the jacket, and the steam trace of the outlet piping of KRC Aider. And heated the KRC KNIA 1's screen to run at 38 rpm. After that, operate the above-mentioned stirring device containing the mixture (112) (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 (112) was supplied to the KRC kneader, and it was confirmed that the mixture (112) came out from the outlet of the KRC eider. After the confirmation, a strand die (* 2 mm × 2 holes) was installed at the outlet of the KRC kneader via a gear pump. Thereafter, the vacuum pump is operated to start reducing the pressure in the KRC kneader, and the pressure is reduced to 270 Torr. After confirming that the distillation of toluene is sufficiently stable, the degree of reduced pressure is further increased and the degree of reduced pressure is 250. To rr, mixture at an internal temperature of 200 ° C (jacket temperature: 202 ° C) and a stream of nitrogen from the above strand die (string-like, diameter: 2 mm, length: approx. 2 m) (113) I got

The obtained mixture (113) (the positive electrode material composition of the present invention) has a solid content of 100.0 wt%, a polymer component weight average molecular weight Mw of 98,000, and an electrode active containing a conductive aid The content ratio of the substance was 69.3 wt%.

[Example 12]

<< Preparation of Polymer Solution >>

<< Mixing process >>

Antioxidant (Api-I Corporation, product name: Yoshinox BB), while flowing a small amount of nitrogen, into a stirring device equipped with a helical ribbon blade (product made by Shinko Environmental Solutions Co., Ltd., product name: Double helical ribbon blade) 0. 095 parts are inserted from the viewing window, and then 21.6 parts of toluene are added, and further, an electrode active material containing 1 to 8 wt% of carbon black as a conductive agent (made by US AVESTOR LLC, product name: Lithio (3) 6 parts of vanadium oxide oxide / force-one blend) was charged from the hopper. Thereafter, the hopper and the like were washed with 9.0 parts of toluene, and the inlet was closed. After the washing, the stirring device was operated (29 rpm) under normal temperature and normal pressure, and mixed by stirring for 60 minutes to obtain a slurry. After completion of the stirring, the volatilization 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.

41. 63 parts of the polymer solution (10) which had been preheated and kept at about 80 ° C. was charged into a stirring apparatus by nitrogen pressure (0.5 kg / cm ² ). After that, the stirrer was operated (29 IT pm), the internal temperature was adjusted to 49.7 ° C (jacket temperature: 50.3 ° C) under normal pressure, and the mixture was stirred for 2 hours to obtain a slurry. After that, the speed of both wings remained as it was, and with the heating of the jacket stopped, this condition was maintained for a whole day and night. The temperature of the jacket after one day and night was 33.0 and the internal temperature was 34.2 ° C. Thus, a slurry-like mixture (121) was obtained.

Mixture (121) has a solids content of 53.0 wt. /. The weight average molecular weight of the polymer component Mw is 124,000, and the content ratio of the electrode active material containing the conductive additive is 68.3 wt%. The evaluation of the dispersion state after mixing was “◎”.

<< Degassing process >>

Turn on the heater of a 30 mm φ twin-screw extruder (made by Plastic Engineering Laboratory, product name: BT- 30- S 2) and set 100 ° C for the 1st, 2nd and 3rd vents. Heat the heat sink, fifth vent, head and die to 200 ° C.

The inside of the stirring apparatus containing the slurry-like mixture (121) in the above mixing step is pressurized to 0.05 MPa with nitrogen, and a gear bond is provided between the stirring apparatus and the first vent of the twin screw extruder. After filling the mixture (1 2 1) until just before the first vent, rotate the 2nd shaft at low speed to start supplying the mixture (1 2 1), and the rotation speed of 2nd shaft up to 100 r pm It raised and confirmed that a mixture (1 2 1) came out of a biaxial die. After that, start the vacuum pump, decompress the second vent to 349 Torr and the third vent to 69 Torr, and discharge 6 kg g from the die of the biaxial rod (cylindrical, diameter : 25 mm) of the mixture (123) was obtained.

The obtained mixture (123) (the positive electrode material composition of the present invention) has a solid content of 100 wt%, a weight average molecular weight Mw of the polymer component is 68,000, and an electrode containing a conductive aid The content of active material was 68.3 wt%.

[Example 1 3]

<< Preparation of polymer solution >>

In the same manner as in Example 12, the solid content is 53.0 wt%, the weight average molecular weight of the polymer component is Mw is 120,000, and the content ratio of the electrode active material containing a conductive additive is 68. A slurry-like mixture (131) which is 3 wt% was obtained.

<< Degassing process >>

Turn on the heater 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, 4th Heat the vent, fifth vent, head and die to 90 ° C.

The inside of the stirring device containing the slurry-like mixture (1 3 1) in the mixing step is pressured with nitrogen to 0.05 MP a, and installed between the stirring device and the first vent of the twin-screw extruder. The gear pump fills the mixture (1 3 1) until just before the first vent, and then the 2nd shaft is rotated at low speed to start the supply of the mixture (1 3 1), and the rotation speed of the 2nd shaft is The temperature was raised to 100 rpm, and it was confirmed that the mixture (1 3 1) came out of the biaxial die. After that, start the vacuum pump, decompress the second vent to .449 Torr and the third vent to 105 Torr, and discharge 6 kg gh from the biaxial die into a rod (cylindrical, diameter: A mixture (133) of 48 mm in length: 300 mm) was obtained.

The obtained mixture (133) (the positive electrode material composition of the present invention) has a solid content of 98.8 to 99. lwt%, a weight average molecular weight of one polymer component, a Mw of 120,000, The content of the electrode active material containing the auxiliary agent was 68.5 wt%.

<< Cooling and Solidification Process >> The mixture (133) obtained after this volatilization is heated to about 90 ° C., and then a two roll roller (manufactured by Kansai Roll Co., Ltd., Product name: 8 × 20 BOX type roll machine, front) Roll temperature: 30. I ;, Post roll temperature: 31.3 C, Guide width: 55 mm, Rotation speed: 2. 4 rpm), the mixture was in the form of a roll, but the mixture was in the roll It adhered and could not be made into a sheet.

[Example 14]

<< Preparation of polymer solution >>

<< Mixing process >>

In the same manner as in Example 12, the solid content is 53.0 wt%, the weight average molecular weight of the polymer component is Mw is 120,000, and the content ratio of the electrode active material containing a conductive additive is 68. A slurry-like mixture (141) of 3 wt% was obtained.

<< Degassing process >>

In the same manner as in Example 12, the solid content is 99. 1 wt%, the weight average molecular weight of the polymer component is Mw is 120,000, and the content ratio of the electrode active material containing the conductive additive is 68. A mixture (143) of rod-like bodies (cylindrical, diameter: 25 mm) of 5 wt% was obtained.

<< Cooling and Solidification Process >>

The mixture (143) obtained after this volatilization is heated to about 90 ° C., and then the rolling double roll (manufactured by Kansai Roll Co., Ltd., Product name: 8 X 20 BOX type roll machine, front roll Temperature: 20.2, temperature of rear roll: 21. 3 ° C, guide width: 55 mm, rotation speed: 2.4 r pm), thickness 2.1 mm, width 83 mm, length 2920 mm sheet I made it. The temperature of this sheet was 45.degree. This sheet is put in an aluminum laminate bag, sufficiently purged with nitrogen, sealed with a heat seal, allowed to stand at room temperature for one day or more, and cooled to obtain a sheet-like mixture (143) (Positive material composition of the present invention) I got

Granulation Process

The obtained sheet is introduced into a sheet cutter (manufactured by Horai Co., Ltd., product name: SGE-220 type) at a supply speed of 1.6 mZh at a temperature of 30 ° C., and the number of rotation of the vertical blade 16. Although it was tried to cut at 4 Hz and 20.3 Hz of the horizontal blade rotation speed, the sheet adhered to the cutter part intensely, and it was not possible to cut it into a square pellet continuously. 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. A process of mixing a polymer solution, an electrode active material and a conductive auxiliary agent to obtain a slurry-like mixture, and volatilizing a solvent in the polymer solution from the slurry-like mixture to such an extent that the mixture does not lose fluidity. And manufacturing the positive electrode material composition for a lithium secondary battery

2. The method for producing a positive electrode material composition for a lithium secondary battery according to claim 1, wherein the solvent is a nonpolar solvent.

3. The positive electrode material composition for a lithium secondary battery according to claim 1, wherein the polymer solution, the electrode active material, and the conductive auxiliary agent are mixed into a homogeneously dispersed slurry-like mixture by the mixing. Production method.

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 and / or conditioning the mixture. The manufacturing method of the positive electrode material composition for lithium secondary batteries as described in any one of the above.

5. The method for producing a positive electrode material composition for a lithium secondary battery according to any one of claims 1 to 4, wherein at least one step of ^^ is performed in an inert gas atmosphere.

6. When the weight average molecular weight of the polymer in the polymer solution is Mw _D, and the weight average molecular weight of the polymer in the mixture after the final step is Mw, the weight average molecular weight decrease determined by the following formula (1) The method for producing a positive electrode material composition for a lithium secondary battery according to any one of claims 1 to 5, wherein the ratio (D _Mw ) is 10% or less.

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

7. The electrode active material is L i _x V _y O _z (where x, y and z are independent of one another, respectively), and 0 × x≤2, y = (mx + 2 z) Zn and z = A real number satisfying (mx + ny) / 2 (where, m is a valence of Li and n is a valence of V and is a real number of 4 or more). The manufacturing method of the positive electrode material composition for lithium secondary batteries in any one of to 6.

8. The method for producing a positive electrode material composition for a lithium secondary battery according to any one of claims 1 to 7, wherein the polymer in the polymer solution is an ionically conductive polyether polymer.