JP6593196B2 - Storage method of composition for non-aqueous secondary battery - Google Patents

Description

  The present invention relates to a method for storing a composition for a non-aqueous secondary battery.

  Non-aqueous secondary batteries such as lithium ion secondary batteries (hereinafter sometimes simply referred to as “secondary batteries”) have the characteristics of being small and lightweight, having high energy density, and capable of repeated charge and discharge. Yes, it is used for a wide range of purposes. Therefore, in recent years, various improvements have been studied for the purpose of further improving the performance of the nonaqueous secondary battery.

  Here, as the battery member provided in the secondary battery, in general, an electrode such as a positive electrode and a negative electrode, and a separator that separates the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode are included. In some cases, an adhesive layer is provided between the separator and the electrode to favorably adhere the separator and the electrode. The electrode generally includes a current collector and an electrode mixture layer formed on the current collector. And in order to adhere | attach each component and each battery member favorably for these contact bonding layers and electrode compound-material layers, the binder composition containing a binder component is normally used. Specifically, the adhesive layer is formed, for example, by applying a slurry composition for an adhesive layer in which non-conductive particles, a binder composition, and the like are dispersed in a dispersion medium, and drying the composition. . The electrode mixture layer is formed, for example, by applying an electrode slurry composition obtained by dispersing an electrode active material, a binder composition or the like in a dispersion medium on a current collector and drying it. Hereinafter, these binder compositions and various slurry compositions may be simply referred to as “battery compositions”.

  On the other hand, in the secondary battery manufacturing process, the various battery compositions as described above are usually stored for a period from the preparation of the battery composition to the use of the battery member manufacturing process. is required. Therefore, in order for the secondary battery to exhibit good battery performance, it is required that the desired characteristics of the battery composition are not deteriorated even after storage of the battery composition. Further, from the viewpoint of the safety of the manufacturing process, when storing the battery composition, it is also required to store it safely for a long period without deforming the container.

  Therefore, in recent years, attempts have been made to improve the storage method of the battery composition used for forming the adhesive layer and the electrode mixture layer in order to achieve further performance improvement of the secondary battery.

  For example, in Patent Documents 1 and 2, an electrode binder composition containing a polymer containing a structural unit derived from acrylonitrile, acrylic acid, butadiene, styrene, and the like and water is placed in a container at a predetermined volume ratio. A storage method has been proposed. Specifically, in Patent Documents 1 and 2, the volume ratio of the void portion excluding the volume occupied by the binder composition for an electrode is suppressed to a low value of 10% or less with respect to the inner volume of the polyethylene and polypropylene container. . The techniques described in Patent Documents 1 and 2 realize a storage method in which aggregates are not visually confirmed even in the binder composition after 6 months of storage, and no foreign matter is generated. It has also been confirmed that the appearance of the container used for storage has not changed. Furthermore, it has been confirmed that no significant voltage drop occurs in the open circuit voltage of the secondary battery.

  Patent Document 3 proposes a storage method in which an aqueous binder composition for lithium secondary batteries having a concentration of aggregates or the like having a predetermined concentration or less is filled in a container at a predetermined volume ratio. Specifically, in Patent Document 3, the concentration of coarse particles and / or aggregates is 500 ppm or less, a polymer containing an acrylate monomer, an acrylonitrile monomer, a methacrylic acid monomer, and the like, and water A polyethylene aqueous container is filled with a binder aqueous dispersion containing the composition so that the porosity in the container is 10% or less. And in the preservation | save method of patent document 3, it suppresses that the aggregate content in a binder composition raises in the binder composition 6 months after a preservation | save. Further, it has been confirmed that the adhesion between the porous film formed using the stored aqueous binder dispersion and the separator and the output characteristics of the secondary battery produced using the aqueous binder dispersion are good.

JP 2012-209258 A JP 2012-248546 A International Publication No. 2015/029835

  However, in the conventional techniques such as Patent Documents 1 to 3, there is room for further study on desirable characteristics of the battery member and / or the secondary battery manufactured using the stored binder composition. Here, as a desirable characteristic of the battery member, for example, in the manufacturing process of the secondary battery, the battery members are high in process so that the stacked battery members do not cause misalignment and the like to cause a decrease in productivity. For example, it has adhesiveness. Examples of desirable secondary battery characteristics include good life characteristics that can be used repeatedly, represented by high cycle characteristics.

  Moreover, when storing the battery composition in the manufacturing process of the secondary battery as described above, it has been continuously demanded that the container being stored can be safely stored without swelling.

  Therefore, the present invention can safely store a battery member and a battery composition used for manufacturing a secondary battery for a long period of time without being deformed, etc. It is an object of the present invention to provide a method for storing a battery composition capable of maintaining good process adhesion between members and cycle characteristics of a secondary battery.

  The present inventor has intensively studied for the purpose of solving the above problems. Then, the present inventor, when storing the battery composition, the battery composition contains a polymer and an organic solvent having a predetermined boiling point, to the viscosity of the battery composition and the storage container for the battery composition. Focusing on the control so that the filling volume is within a predetermined range. And even if it was a case where the said composition for batteries was stored for a fixed period, it confirmed that a storage container could be stored with high safety | security without a deformation | transformation etc. of a storage container. Further, when the adhesive layer is formed using the battery composition after storage, the electrode and the separator through the adhesive layer exhibit good process adhesion during the manufacturing process of the secondary battery, and The present inventors have found that a secondary battery including the adhesive layer exhibits good cycle characteristics at high temperatures, and completed the present invention.

That is, this invention aims to solve the above-mentioned problem advantageously, and the storage method of the composition for a non-aqueous secondary battery of the present invention comprises the composition for a non-aqueous secondary battery in a container. A method for storing a composition for a non-aqueous secondary battery to be stored, wherein the composition for a non-aqueous secondary battery contains a polymer and an organic solvent, and the boiling point of the organic solvent is 30 ° C or higher and 150 ° C or lower, The composition for a non-aqueous secondary battery has a viscosity at a shear rate of 1 s ⁻¹ of 100 mPa · s to 1000 mPa · s, and from the internal volume of the container to the internal volume of the container, the non-aqueous secondary battery The volume ratio (void ratio) of the void portion excluding the volume occupied by the composition for use in the container is 5 volume% or more and 50 volume% or less. Thus, the battery composition to be stored contains a polymer and an organic solvent having a predetermined boiling point, is in a predetermined viscosity range, and the porosity in the storage container filled with the battery composition is in a predetermined range. By controlling the inside, the battery composition can be safely stored without the storage container expanding and rupturing. Further, the adhesive layer formed using the battery composition after storage favorably adheres the electrode and the separator, and suppresses positional deviation of the battery member during the manufacturing process of the secondary battery. Furthermore, a secondary battery comprising an adhesive layer formed using the battery composition after storage exhibits good cycle characteristics even at high temperatures.
In the present invention, “viscosity at a shear rate of 1 s ⁻¹ ” refers to the viscosity at a temperature of 23 ° C. measured using a B-type viscometer.
In the present invention, the “porosity” can be measured according to the method of this example using a ruler (compliant with JIS).

Here, in the method for storing a composition for a non-aqueous secondary battery according to the present invention, it is preferable that the oxygen concentration in the void is 1.0% by mass or less. When storing the battery composition, if the oxygen concentration in the void is equal to or less than the above-mentioned concentration, the battery composition during storage can be prevented from reacting and agglomerating, thereby forming the battery composition after storage. This is because the process adhesiveness of the electrode and separator through the adhesive layer is further enhanced.
In the present invention, the “oxygen concentration” can be measured according to the method of this embodiment using an oxygen concentration meter (product name “OX-102” manufactured by Yokogawa Electric Corporation).

Moreover, in the storage method of the composition for non-aqueous secondary batteries of this invention, it is preferable that the water | moisture-content density | concentration of the said space | gap part is 100 mass ppm or less. If the water content in the voids during storage of the battery composition is less than the above concentration, aggregation of the battery composition during storage can be suppressed, thereby forming the battery composition after storage. This is because the process adhesiveness of the electrode and the separator through the adhesive layer is further enhanced.
In the present invention, the “water concentration” can be measured according to the method of this example using a Karl Fischer moisture meter (product name “CA-200” manufactured by Mitsubishi Chemical Corporation).

  Moreover, in the storage method of the composition for non-aqueous secondary batteries of this invention, it is preferable that the inner wall of the said container is resin. If the inner wall of the container used for storage is a resin, the process adhesion between the battery members is further increased through the adhesive layer formed using the battery composition after storage, and the secondary provided with the adhesive layer This is because the high-temperature cycle characteristics of the battery are further enhanced.

In the method for storing a composition for a non-aqueous secondary battery according to the present invention, the absolute value | SP _diff | = | SP _p − of the difference between the solubility parameter SP _p of the polymer and the solubility parameter SP _s of the organic solvent. SP _s | is preferably 1.5 or more and 6.0 or less. If the difference in the solubility parameter between the polymer and the organic solvent in the battery composition is within the above range, the adhesive layer formed using the battery composition after storage has the electrodes and separators for reasons described later. This is because the adhesiveness can be further increased and the process adhesion between the battery members during the battery manufacturing process can be further enhanced. Moreover, it is because a secondary battery provided with the said contact bonding layer can make high temperature cycling characteristics exhibit more favorable.
In the present invention, the “solubility parameter (hereinafter also simply referred to as“ SP ”or“ SP value ”) refers to a solubility parameter, which is a value that can serve as an index for evaluating affinity between substances. That is, if the SP values of two substances are close to each other, it means that the substances have a high affinity for each other. Specifically, when one of two substances having substantially the same SP value is a polymer and the other is a solvent, it means that the solubility of the polymer in the solvent is high.
In the present invention, the “SP value” of each of the polymer and the organic solvent is calculated by the method described later using the Fedors calculation method.

  According to the present invention, even when the battery composition used for manufacturing the battery member and the secondary battery is stored for a long period of time, the container can be safely stored without being deformed, and the battery. It is possible to provide a method for storing a battery composition that can maintain good process adhesion between members and cycle characteristics of a secondary battery.

FIG. 1 is a schematic view of a stirring device used in an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail.

(Storage method for non-aqueous secondary battery composition)
The method for storing the composition for a non-aqueous secondary battery of the present invention includes, for example, formation of a battery member such as an adhesive layer and an electrode mixture layer, or a part of the battery member, provided in a non-aqueous secondary battery such as a lithium ion secondary battery This is a method for storing and preserving the battery composition used for the battery for a certain period in the battery manufacturing process.
In the method for storing a non-aqueous secondary battery composition of the present invention, the battery composition contains a predetermined organic solvent, has a predetermined viscosity, and stores the battery composition with a predetermined porosity. Therefore, even when the battery composition is stored for a long period of time, the storage container is excellent in storage safety without causing expansion or rupture. In addition, since the battery composition after storing the battery composition for a long period of time is used in the battery manufacturing process, the process has excellent process adhesion between battery members, and the resulting secondary battery has a high temperature. The cycle characteristics are excellent, that is, the lifetime of the obtained secondary battery is long.

<Battery composition>
The battery composition used in the storage method of the present invention contains a polymer and an organic solvent having a predetermined boiling point, and may optionally contain other components. Further, the battery composition stored according to the storage method of the present invention has a viscosity at a shear rate of 1 s ⁻¹ controlled within a predetermined range. The battery composition is usually in a state where the polymer is well dispersed (good dispersion) in the organic solvent.
Here, the battery composition is not particularly limited, for example, a binder composition that plays a role as a binder; the binder composition includes, for example, a non-conductive material including inorganic particles and / or organic particles. Examples include a slurry composition for an adhesive layer to which particles are added; a slurry composition for electrodes in which an electrode active material is added to a binder composition; and the like.

<< Polymer >>
The polymer is not particularly limited as long as it is a polymer that can adjust the viscosity of the battery composition within a predetermined range described later. For example, any polymer such as a conjugated diene polymer, an acrylic polymer, or an unsaturated carboxylic acid polymer can be used as the polymer.

  Here, the conjugated diene polymer is a polymer containing a conjugated diene monomer unit. A specific example of the conjugated diene polymer is not particularly limited, and is a copolymer containing an aromatic vinyl monomer unit such as a styrene-butadiene copolymer (SBR) and an aliphatic conjugated diene monomer unit. Butadiene rubber (BR); copolymer containing conjugated diene monomer unit and nitrile group-containing monomer unit such as acrylonitrile-butadiene copolymer (acrylic rubber, NBR); and conjugated diene monomer Examples thereof include a hydrogenated polymer obtained by hydrogenating a copolymer containing units and nitrile group-containing monomer units.

The acrylic polymer is a polymer containing a (meth) acrylic acid ester monomer unit. Here, as the (meth) acrylic acid ester monomer capable of forming a (meth) acrylic acid ester monomer unit, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, 2 -Alkyl esters of (meth) acrylic acid such as ethylhexyl acrylate can be used.
In the present invention, “(meth) acryl” means acryl and / or methacryl.

  The unsaturated carboxylic acid polymer is a polymer containing an unsaturated carboxylic acid monomer unit. Here, as the unsaturated carboxylic acid capable of forming the unsaturated carboxylic acid monomer unit, acrylic acid, methacrylic acid, itaconic acid and the like can be used.

  Among the above-described polymers, the polymer contained in the battery composition includes a conjugated diene monomer unit and a viewpoint of being easily adjusted to a desired viscosity and excellent in heat resistance, chemical resistance, weather resistance, and the like. A hydrogenated polymer obtained by hydrogenating a copolymer containing a nitrile group-containing monomer unit is preferred, and a hydrogenated polymer obtained by hydrogenating a copolymer containing an acrylonitrile unit and a butadiene unit (H-NBR) is more preferred. preferable.

[Method for preparing polymer]
The polymerization mode of the polymer is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method may be used. As the polymerization reaction, addition polymerization such as ionic polymerization, radical polymerization, and living radical polymerization can be used.
Here, when the polymer is a hydride of a copolymer containing an acrylonitrile unit and a butadiene unit, for example, a monomer composition containing acrylonitrile and butadiene may be arbitrarily added as a chain transfer agent. In the presence of, a polymerization initiator is used for polymerization to obtain a copolymer, and then the obtained copolymer is hydrogenated (hydrogenated). The method for hydrogenating the polymer is not particularly limited, and a general method using a catalyst (see, for example, International Publication No. 2012/165120, International Publication No. 2013/080989 and JP2013-8485A). Can be used.
And generally used emulsifiers, polymerization initiators, chain transfer agents and the like that can be used for the polymerization can be used, and the amount used can also be generally used.

  For example, the emulsifier may be any of an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. Specific examples of the anionic surfactant include sodium dodecyl sulfate such as sodium lauryl sulfate, ammonium dodecyl sulfate such as ammonium lauryl sulfate, sodium octyl sulfate, sodium decyl sulfate, sodium tetradecyl sulfate, sodium hexadecyl sulfate, and sodium octadecyl sulfate. Ester salts; sodium dodecyl diphenyl ether disulfonate, sodium succinate dialkyl ester, sodium dodecyl benzene sulfonate such as sodium lauryl benzene sulfonate, alkyl benzene sulfonate such as sodium hexadecyl benzene sulfonate; dodecyl sulfonic acid such as sodium lauryl sulfonate Sodium, sodium tetradecyl sulfonate Aliphatic sulfonates such as arm; and the like, may be a so-called reactive emulsifier having an unsaturated bond. Of these, sodium alkylbenzene sulfonate is preferably used. One of these may be used alone, or two or more of these may be used in combination at any ratio.

  Examples of the polymerization initiator include sodium persulfate, ammonium persulfate, and potassium persulfate. Among these, it is preferable to use ammonium persulfate. One of these may be used alone, or two or more of these may be used in combination at any ratio.

  The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-stearyl mercaptan; Xanthogen compounds such as xanthogen disulfide and diisopropylxanthogen disulfide; thiuram compounds such as terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetramethylthiuram monosulfide; 2,6-di-t-butyl-4-methylphenol Phenolic compounds such as styrenated phenols; allyl compounds such as allyl alcohol; halogenated hydrocarbon compounds such as dichloromethane, dibromomethane, carbon tetrabromide ; Thioglycolic acid, thiomalate, 2-ethylhexyl thioglycolate, diphenylethylene, etc. α- methylstyrene dimer. Among these, from the viewpoint of suppressing side reactions, alkyl mercaptans are preferable, and t-dodecyl mercaptan is more preferable. These may be used alone or in combination of two or more.

<< Organic solvent >>
[boiling point]
The boiling point of the organic solvent contained in the battery composition needs to be 30 ° C. or higher and 150 ° C. or lower. The boiling point of the organic solvent is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, preferably 120 ° C. or lower, and more preferably 100 ° C. or lower. If an organic solvent having a boiling point of 30 ° C. or higher is used, a film of the battery composition is formed on the inner wall of the container because the organic solvent volatilizes extremely easily during storage of the battery composition. I can prevent it. As a result, for example, even when the adhesive layer is formed using the battery composition stored for a long time, the process adhesiveness between the battery members via the adhesive layer can be improved. Further, when an organic solvent having a boiling point of 150 ° C. or lower is used, for example, when the adhesive layer is formed by applying and drying the battery composition containing the organic solvent, the applied battery composition is appropriate. Since it can be easily dried by volatilizing easily, the formed adhesive layer exhibits good process adhesion. Further, as the battery members are well bonded, the manufactured secondary battery exhibits good cycle characteristics.

Here, when the applied battery composition easily volatilizes and exhibits good drying properties, for example, the reason why the process adhesiveness between the battery members through the formed adhesive layer is good is clear. However, it is guessed that it is as follows.
That is, when the applied battery composition is dried, the polymer component easily moves in the adhesive layer with the volatility of the organic solvent contained in the battery composition. As a result, a large amount of polymer can be deposited on the surface of the adhesive layer in the formed adhesive layer. That is, the process adhesiveness between battery members through the said adhesive layer can be improved because many polymers which bear a binding function exist on the surface of the adhesive layer which contacts a battery member.

[type]
The type of organic solvent is not particularly limited as long as the boiling point is within the above range. Examples of the organic solvent include diethyl ether, methylene chloride, acetone, chloroform, methanol, tetrahydrofuran, hexane, ethyl acetate, ethanol, methyl ethyl ketone, benzene, 2-propanol, acetonitrile, 1-propanol, formic acid, toluene, 1-butanol, Examples include acetic acid, xylene, diethyl carbonate, ethyl methyl carbonate, ethylene propionate, and propyl propionate. Among these, acetone, toluene, or xylene is preferably used, and acetone is more preferably used, from the viewpoint of having a boiling point suitable for storage and allowing the polymer to be favorably dispersed. These may be used alone or in combination of two or more at any ratio, but when two or more organic solvents are used in combination, the boiling point of any one organic solvent is What is necessary is just to be in the said predetermined range.

<< Other ingredients >>
The battery composition may further contain other components in addition to the polymer and the organic solvent described above. Other components that can be further contained in the battery composition are not particularly limited. For example, components such as a surface tension adjuster, a viscosity adjuster, a reinforcing material, an electrolytic solution additive, a dispersant such as cyanoethylated pullulan, etc. Is mentioned. These are not particularly limited as long as they do not affect the battery reaction, and known ones such as those described in International Publication No. 2012/115096 can be used. In addition, these components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

<< Method for Preparing Binder Composition >>
When the battery composition is a binder composition, the binder composition can be prepared, for example, by mixing the above-described polymer and organic solvent by a known method.
The mixing can be performed while adjusting the concentration of the mixture, for example, so that the binder composition has a predetermined viscosity described later.

<< Slurry composition for adhesive layer >>
When the battery composition is a slurry composition for an adhesive layer, the slurry composition for the adhesive layer usually contains, for example, non-conductive particles with respect to the above-described polymer, organic solvent, and any other components. It is prepared by further mixing. The mixing method in particular of these components is not restrict | limited, It can mix by a known method. For example, a method of batch-mixing a polymer, an organic solvent, any other component, and non-conductive particles; preparing a dispersion solvent in which the non-conductive particles and the organic solvent are dispersed in advance; The method of mixing separately; etc. are mentioned. In the mixing, the dispersion may be performed uniformly and efficiently using a known dispersing device and classifying device. Moreover, when preparing the slurry composition for adhesion layers using the dispersion liquid of a polymer, you may utilize the liquid part which the dispersion liquid contains as a dispersion medium of the slurry composition for adhesion layers as it is.
The mixing can be performed while adjusting the concentration of the mixture, for example, so that the adhesive layer slurry composition has a predetermined viscosity described later.

[Non-conductive particles]
Non-conductive particles are not particularly limited, and may include known non-conductive particles used for adhesive layers for secondary batteries. Specifically, for example, inorganic fine particles can be used as the non-conductive particles. As the non-conductive particles, both the inorganic fine particles and organic fine particles other than the polymer used in the battery composition can be used, but usually only the inorganic fine particles are used. Especially, as a material of nonelectroconductive particle, the material which exists stably in the use environment of a non-aqueous secondary battery and is electrochemically stable is preferable. From this point of view, preferable examples of the non-conductive particle material include aluminum oxide (alumina), hydrated aluminum oxide (boehmite), silicon oxide, magnesium oxide (magnesia), calcium oxide, titanium oxide (titania). Oxide particles such as BaTiO ₃ , ZrO, alumina-silica composite oxide; nitride particles such as aluminum nitride and boron nitride; covalently bonded crystal particles such as silicon and diamond; barium sulfate, calcium fluoride, barium fluoride Insoluble ion crystal particles such as; clay fine particles such as talc and montmorillonite; In addition, these particles may be subjected to element substitution, surface treatment, solid solution, and the like as necessary.
In addition, the nonelectroconductive particle mentioned above may be used individually by 1 type, and may be used in combination of 2 or more types.

<< Slurry composition for electrode >>
When the battery composition is an electrode slurry composition, the electrode slurry composition is usually further mixed with an electrode active material, for example, with respect to the polymer, the organic solvent, and any other components described above. It is prepared by. The mixing method in particular of these components is not restrict | limited, It can mix by a known method. Known mixing methods include, for example, a ball mill, a sand mill, a bead mill, a pigment disperser, a crushed grinder, an ultrasonic disperser, a homogenizer, a planetary mixer, a fill mix, etc. By mixing the slurry, a slurry composition can be prepared. Moreover, when preparing the slurry composition for electrodes using the dispersion liquid of a polymer, you may utilize the liquid part which the dispersion liquid contains as a dispersion medium of the slurry composition for electrodes as it is. The mixing can be performed, for example, while adjusting the concentration of the mixture so that the electrode slurry composition has a predetermined viscosity described later.

Further, when preparing an electrode slurry composition separately from the battery composition, the same mixing method can be used. For example, an electrode active material and a polymer functioning as a binder are mixed in an arbitrary solvent. It can be prepared by dissolving or dispersing in. Here, the polymer functioning as a binder is not particularly limited, and the polymers listed as the polymer contained in the battery composition may be used, and a fluorine-containing polymer represented by polyvinylidene fluoride. Other polymers such as may be used. In addition, the solvent is not particularly limited, the solvents listed as the organic solvent contained in the battery composition may be used, other organic solvents represented by N-methylpyrrolidone may be used, Water may be used.
Hereinafter, although the case where a non-aqueous secondary battery is a lithium ion secondary battery is demonstrated as an example, this invention is not limited to this.

[Electrode active material]
The electrode active material is a material that transfers electrons at the electrode of the secondary battery. And as an electrode active material for lithium ion secondary batteries, the substance which can occlude and discharge | release lithium is used normally.
[[Positive electrode active material]]
The positive electrode active material is not particularly limited, and lithium-containing cobalt oxide (LiCoO ₂ ), lithium manganate (LiMn ₂ O ₄ ), lithium-containing nickel oxide (LiNiO ₂ ), lithium of Co—Ni—Mn containing composite oxide (Li (Co Mn Ni) O 2), Ni-Mn-Al lithium-containing composite oxide, Ni-Co-Al lithium-containing composite oxide, olivine-type lithium iron phosphate (LiFePO _4), Lithium-rich lithium manganese phosphate (LiMnPO ₄ ), Li ₂ MnO ₃ —LiNiO ₂ solid solution, Li _{1 + x} Mn _2−x O ₄ (0 <X <2) Examples include known positive electrode active materials such as Ni _0.17 Li _0.2 Co _0.07 Mn _0.56 ] O ₂ and LiNi _0.5 Mn _1.5 O ₄ .
In addition, the compounding quantity and particle diameter of a positive electrode active material are not specifically limited, It can be made to be the same as that of the positive electrode active material used conventionally.

[[Negative electrode active material]]
In addition, specific examples of the negative electrode active material include, but are not limited to, a carbon-based negative electrode active material, a metal-based negative electrode active material, and a negative electrode active material obtained by combining these materials.

Examples of the carbon-based active material include graphitizable carbon and non-graphitizable carbon having a structure close to an amorphous structure typified by glassy carbon.
Here, as the graphitizable carbon, for example, a carbon material using tar pitch obtained from petroleum or coal as a raw material can be mentioned. Specific examples include coke, mesocarbon microbeads (MCMB), mesophase pitch carbon fibers, pyrolytic vapor grown carbon fibers, and the like.
In addition, examples of the non-graphitizable carbon include a phenol resin fired body, polyacrylonitrile-based carbon fiber, pseudo-isotropic carbon, furfuryl alcohol resin fired body (PFA), and hard carbon.

Furthermore, examples of the graphite material include natural graphite and artificial graphite.
Here, as the artificial graphite, for example, artificial graphite obtained by heat-treating carbon containing graphitizable carbon mainly at 2800 ° C. or higher, graphitized MCMB heat-treated at 2000 ° C. or higher, and mesophase pitch-based carbon fiber at 2000 ° C. Examples thereof include graphitized mesophase pitch-based carbon fibers that have been heat-treated.

  Further, the metal-based negative electrode active material is an active material containing a metal, and usually includes an element capable of inserting lithium in the structure, and the theoretical electric capacity per unit mass when lithium is inserted is 500 mAh / The active material which is more than g. Examples of the metal active material include lithium metal and a single metal capable of forming a lithium alloy (for example, Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, Si, Sn). , Sr, Zn, Ti, etc.) and alloys thereof, and oxides, sulfides, nitrides, silicides, carbides, phosphides, and the like thereof. Among these, as the metal-based negative electrode active material, an active material containing silicon (silicon-based negative electrode active material) is preferable. This is because the capacity of the lithium ion secondary battery can be increased by using the silicon-based negative electrode active material.

Examples of silicon-based negative electrode active materials include silicon (Si), alloys containing silicon, SiO, SiO _x , and a composite of a Si-containing material obtained by coating or combining a Si-containing material with conductive carbon and conductive carbon. Etc. In addition, these silicon type negative electrode active materials may be used individually by 1 type, and may be used in combination of 2 types.
Among these, as the negative electrode active material, a carbon-based active material is preferable, a graphite material is more preferable, and artificial graphite is more preferable.

<< Viscosity of battery composition >>
Here, the viscosity of the battery composition needs to be 100 mPa · s or more and 1000 mPa · s or less at a shear rate of 1 s ⁻¹ . The viscosity of the battery composition is preferably 120 mPa · s or higher, more preferably 150 mPa · s or higher, and preferably 900 mPa · s or lower, and 800 mPa · s at a shear rate of 1 s ⁻¹ . -More preferably, it is s or less. If the viscosity at a shear rate of 1 s ⁻¹ of the battery composition is 100 mPa · s or more, for example, the battery composition itself or various slurry compositions prepared using the battery composition are applied and dried. Thus, when the adhesive layer or the electrode mixture layer is formed, the coating property of the battery composition or the slurry composition to the substrate is improved. As a result, the process adhesiveness between the battery members through the formed adhesive layer or electrode mixture layer is improved. Moreover, if the viscosity of the battery composition at a shear rate of 1 s ⁻¹ is 1000 mPa · s or less, the battery composition has a moderately low viscosity when storing the battery composition, and the battery inner wall is used for the battery. Formation of a film of the composition can be prevented. As a result, the generation of foreign matter or the like from the battery composition stored for a long period of time is suppressed. For example, even when the adhesive layer is formed using the battery composition, the battery member via the adhesive layer is used. The process adhesion can be improved.

<< Solubility parameter (SP value) >>
In the battery composition, the absolute value | SP _diff | = | SP _p −SP _s | of the difference between the solubility parameter SP _p of the polymer and the solubility parameter SP _s of the organic solvent is 1.5 or more. Preferably, it is 2.0 or more, more preferably 2.5 or more, preferably 6.0 or less, more preferably 5.0 or less, and 4.5 or less. More preferably it is. If the absolute value | SP _diff | of the SP value difference is 1.5 or more, it is possible to suppress excessive dissolution of the polymer in the organic solvent, and process adhesion between battery members such as a separator and an electrode. It is because it can improve more. Further, if the absolute value | SP _diff | of the SP value difference is 6.0 or less, it is possible to secure good solubility of the polymer in the organic solvent and further improve the process adhesion between the battery members. Because it can. As a result, a battery composition having | SP _diff | within the above range can be stored more safely over a long period of time while suppressing expansion of the container, and the battery composition after storage. This is because high cycle characteristics can be exhibited by a secondary battery manufactured using a product.
In general, it is preferable that SP _p > SP _s holds between the solubility parameter SP _p of the polymer and the solubility parameter SP _s of the organic solvent.

Here, the solubility parameter can be calculated by, for example, a method of estimating from a molecular structure or a method of estimating from a physical property value. Examples of the method of estimating from the molecular structure include a Small calculation method, a Rheineck and Lin calculation method, a Krevelen and Hoftizer calculation method, a Fedors calculation method, a Hansen calculation method, and a Hoy calculation method. Examples of the method of estimating from the physical property value include a method of obtaining from latent heat of vaporization, a method of Hildebrand Rule, a method of surface tension, a method of obtaining from a solubility value, and a method of obtaining from a refractive index. Furthermore, the SP value of a substance whose composition or compound name is difficult to specify can be calculated by, for example, a cloud point titration method. Among them, it is preferable to use the Fedors calculation method.
Here, in the Fedors calculation method, the SP value is calculated based on the Hildebrand theory using the cohesive energy and the molar volume. Specifically, when the cohesive energy of each unit contained in the polymer is E _coh and the molar volume of each unit is V, the SP value can be calculated according to the following formula (1).
SP = [ΣE _coh / ΣV] ^1/2 (1)

For example, as an example, the case where the polymer is a hydride (H-NBR) of a copolymer containing an acrylonitrile unit and a butadiene unit will be described more specifically.
Acrylonitrile has one secondary carbon (—CH ₂ —) unit, one tertiary carbon (—CH <) unit, and one nitrile group (—CN) unit. The cohesive energy E _coh and the molar volume V of each of these units are as follows according to the values proposed by Fedors.
_{· -CH 2 -: E coh =} 4940J / mol, V = 16.1cm 3 / mol
-CH <: E _coh = 3430 J / mol, V = -1.0 cm ³ / mol
-CN: E _coh = 25530 J / mol, V = 24.0 cm ³ / mol
Therefore, these values are calculated based on the equation (1), the SP value SP _AN acrylonitrile,
SP _AN = [(4940 + 3430 + 25530) / (16.1-1.0 + 24.0)] ^1/2 = 29.4 (J / cm ³ ) ^1/2 ≒ 29.4 MPa ^1/2
It becomes.
On the other hand, straight-chain alkylene having 4 carbon atoms in which butadiene is hydrogenated has 4 secondary carbon (—CH ₂ —) units. Accordingly, the SP value SP _alk is the same as described above.
SP _alk = [(4940 × 4) / (16.1 × 4)] ^1/2 = 17.5 (J / cm ³ ) ^1/2 ≒ 17.5 MPa ^1/2
It becomes.
A polymer comprising an acrylonitrile unit derived from an acrylonitrile monomer and a linear alkylene structural unit having 4 carbon atoms, wherein the proportion of the acrylonitrile unit in the polymer is a ₁ % by mass and the linear chain having 4 carbon atoms. The SP value SP _p of a polymer having an alkylene structural unit ratio of a ₂ % by mass can be calculated according to the following formula (2).
SP _p (MPa ^1/2 ) = (SP _AN × a ₁ + SP _alk × a ₂ ) / (a ₁ + a ₂ ) (2)
In addition, the ratio of the unit or structural unit derived from each monomer contained in the polymer is calculated based on the number of charged parts (mixing ratio) at the time of preparing the polymer when a polymer is newly prepared. be able to. Or about a polymer, it can also calculate based on the ratio of each monomer unit in a polymer, or a structural unit measured, for example using gas chromatography.

Further, the above formula (2) is not limited to the polymer composed of the specific monomer unit or structural unit, but also for a polymer having other monomer units or structural units as shown in the following formula (3). Can be generalized to:
^{_{SP p (MPa 1/2) = (}} SP 1 × a 1 + SP 2 × a 2 + ··· + SP n × a n) / (a 1 + a 2 + ··· + a n) ··· (3)
Here, SP ₁ is the SP value of the first monomer unit or structural unit in the polymer, and a ₁ is the ratio (mass%) in the polymer. SP ₂ to SP _n, for even a ₂ ~a _n, respectively, a SP value of the monomer units or structural units of the second to n in the polymer, their proportion in the polymer (wt%) It is.

The solubility parameter SP _s of the organic solvent can be calculated in the same manner as the solubility parameter of the polymer. In the present application, the Fedors calculation method is used to calculate the solubility parameter.

<Container>
The above-described battery composition is stored in a container. The kind of the container used for the storage is not particularly limited, and for example, a drum can, a funnel can, a pail can, a plastic tank, a pouch-type container, or the like can be used.
Further, the material of the container is not particularly limited, and examples thereof include metals such as resin and stainless steel. Especially, it is preferable that the inner wall of a container is resin, it is more preferable that an inner wall of a container is polyethylene or a polypropylene, and it is still more preferable that it is polyethylene. For example, when a pouch-type container is used, the sheet material of the liquid contact portion, that is, the sheet material inside the pouch-type container is preferably a resin, more preferably polyethylene or polypropylene. More preferably. In this way, if the inner wall of the container is a resin, impurities such as metals from the inner wall of the container can be prevented from eluting into the battery composition during storage of the battery composition. This is because, even when stored for a long period of time, the cycle characteristics of a secondary battery manufactured using the stored battery composition can be further improved.
Furthermore, the internal volume of the container used for storage is not particularly limited, but is preferably 10L or more and 200L or less from the viewpoint of ease of filling and storage. When using a polytank and a pouch-type container Is more preferably 10L or more and 25L or less, and more preferably 100L or more and 200L or less when a drum can is used.

<< Surface roughness of inner wall of container >>
Here, the surface roughness of the inner wall of the container used for storage of the battery composition is preferably arithmetic mean roughness Ra of 10 μm or less, more preferably 5 μm or less, and further preferably 3 μm or less. preferable. If the surface roughness Ra of the inner wall of the container is 10 μm or less, the contact area between the battery composition and the inner wall of the battery during storage of the battery composition can be reduced, and the battery composition is placed on the inner wall of the container. It is because it can suppress that the film of this is formed. As a result, for example, even when the adhesive layer is formed using the battery composition stored for a long time, the process adhesiveness between the battery members via the adhesive layer can be improved.
In the present invention, the “surface roughness of the inner wall of the container” can be measured using, for example, a surface shape measuring machine described later.

<Porosity>
Here, when storing the battery composition, the volume ratio (void ratio) of the void portion excluding the volume occupied by the battery composition in the container from the inner volume of the container with respect to the inner volume of the container is 5% by volume or more. It is necessary to be 50% by volume or less. The porosity is preferably 6% by volume or more, more preferably 7% by volume or more, preferably 45% by volume or less, and more preferably 40% by volume or less. If the battery composition is filled and stored with a porosity of 5% by volume or more, the volume of the battery composition and / or the internal pressure of the container is slightly reduced during storage due to temperature changes that may occur in a normal environment. Even if it is increased or decreased, since the container can be prevented from bursting or changing its shape, the battery composition can be safely stored for a long period of time. In addition, if the porosity is 50% by volume or less, the contact area between the battery composition and the inner wall of the container can be kept small, so that the battery composition film is formed on the inner wall of the container during storage of the battery composition. Can be suppressed. As a result, for example, even when the adhesive layer is formed using the battery composition stored for a long time, the process adhesiveness between the battery members via the adhesive layer can be improved.

<Oxygen concentration>
In storage of the battery composition, the oxygen concentration in the void is preferably 1.0% by mass or less, more preferably 0.9% by mass or less, and 0.8% by mass or less. More preferably, it can be 0 mass%. If the oxygen concentration in the void portion is 1.0% by mass or less, the battery composition can be prevented from oxidizing and agglomerating during storage of the battery composition. This is because even when the adhesive layer is formed using the battery composition stored in the above manner, the process adhesiveness between the battery members via the adhesive layer can be further improved.

<Moisture concentration>
Further, when storing the battery composition, the water content of the voids is preferably 100 ppm by mass or less, more preferably 80 ppm by mass or less, still more preferably 60 ppm by mass or less, It can be 0 mass ppm. If the moisture concentration in the voids is 100 mass ppm or less, the battery composition can be prevented from aggregating during storage of the battery composition. For example, the battery composition stored for a long period of time This is because even when the adhesive layer is formed by using the adhesive, the process adhesiveness between the battery members via the adhesive layer can be further improved.

<Storage temperature and storage period>
When storing the battery composition, it is preferable to keep the storage temperature in a sealed container filled with the battery composition in an environment of 5 ° C. or higher and 40 ° C. or lower. The storage period is preferably 1 month or more and 24 months or less. This is because if the storage temperature and storage period are within the above ranges, the battery composition can be stored more safely without deforming the shape of the container used for storage. Moreover, even when, for example, an adhesive layer is formed using the battery composition after storage, it is possible to further suppress deterioration of process adhesion between battery members via the adhesive layer, and This is because deterioration of the cycle characteristics of the secondary battery provided with the adhesive layer can be further suppressed.

<How to fill the container>
The method for filling the battery composition into the container is not particularly limited as long as the porosity described above is satisfied. In addition, from the viewpoint of maintaining the oxygen concentration, moisture concentration, storage temperature, and the like within the above-described preferable ranges, it is preferable to fill the container with the battery composition while blocking outside air.

(Non-aqueous secondary battery)
The battery composition stored for a certain period of time according to the method for storing the non-aqueous secondary battery composition of the present invention is not particularly limited, and includes a binder composition, an adhesive layer slurry composition, an electrode slurry composition, and the like. Is used for manufacturing battery members and manufacturing secondary batteries.
The battery composition stored for a certain period of time according to the method for storing a non-aqueous secondary battery composition of the present invention has the above-mentioned predetermined composition and properties and is stored with the above-mentioned predetermined porosity. Therefore, the secondary battery manufactured using the battery composition exhibits good cycle characteristics, particularly high-temperature cycle characteristics.

Here, the secondary battery generally includes an electrode (positive electrode, negative electrode), a separator, and an electrolyte solution that is responsible for ion migration between the electrodes in the battery, and, for example, provides good adhesion between the electrode and the separator. An adhesive layer may be further provided.
In addition, battery members such as a positive electrode, a negative electrode, and a separator included in the secondary battery are usually arranged such that the positive electrode is in contact with one side of the separator and the negative electrode is in contact with the other side of the separator. More specifically, the positive electrode mixture layer side is disposed on one side of the separator, and the negative electrode mixture layer side is disposed on the other side of the separator so as to contact the separator. Moreover, when a secondary battery is further provided with an adhesive layer, the adhesive layer can be formed on both surfaces of the separator, for example, without any particular limitation. That is, the positive electrode mixture layer side can be disposed so as to contact the adhesive layer formed on one side of the separator and the negative electrode mixture layer side can be in contact with the adhesive layer formed on the other side of the separator.

<Separator>
The separator is not particularly limited. For example, a microporous film using a polyolefin resin (polyethylene, polypropylene, polybutene, polyvinyl chloride), a polyamide such as polyethylene terephthalate, polycycloolefin, polyether sulfone, or nylon. , Microporous membranes using resins such as polyimide, polyimideamide, polyaramid, polycycloolefin, polytetrafluoroethylene, woven or non-woven fabrics using polyolefin fibers, aggregates of particles made of insulating materials, etc. It is done. Among these, the thickness of the entire separator can be reduced, thereby increasing the ratio of the electrode mixture layer in the non-aqueous secondary battery and increasing the capacity per volume, A microporous film using a polyolefin resin (polyethylene, polypropylene, polybutene, polyvinyl chloride) is preferred. Among these, a microporous film made of polypropylene resin is more preferable.

<Adhesive layer>
An adhesive layer is a battery member provided in order to adhere | attach an electrode and a separator favorably, for example. The adhesive layer is not particularly limited, and may be formed, for example, on the positive electrode mixture layer included in the positive electrode, on the negative electrode mixture layer included in the negative electrode, and / or on the separator. You may form in. Especially, it is preferable to form an adhesive layer on a separator from a viewpoint which exhibits work ease and high process adhesiveness, and it is more preferable to form on both surfaces of a separator.
Hereinafter, although the case where an adhesive layer is formed on a separator is demonstrated as an example, this invention is not limited to this.

<< Adhesive Layer Formation Method >>
The adhesive layer includes, for example, a step of applying the above-described adhesive layer slurry composition on the separator (application step) and a step of drying the adhesive layer slurry composition applied on the separator (drying step). Formed through.

[Coating process]
It does not specifically limit as a method of apply | coating the said slurry composition for contact bonding layers on a separator, A well-known method can be used. Specifically, as a coating method, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method, or the like can be used. At this time, the slurry composition for the adhesive layer may be applied only to one side of the separator or may be applied to both sides, but it is preferably applied to both sides. The thickness of the slurry film on the separator after coating and before drying can be appropriately set according to the thickness of the adhesive layer obtained by drying.

[Drying process]
The method for drying the slurry composition for the adhesive layer applied on the separator is not particularly limited, and a known method can be used. For example, a drying method using hot air, hot air, low-humidity air, vacuum drying method, infrared ray, A drying method by irradiation with an electron beam or the like can be mentioned. Thus, by drying the slurry composition for an adhesive layer on the separator, an adhesive layer can be formed on the separator, and a separator with an adhesive layer including the separator and the adhesive layer can be obtained.

<Electrode>
The electrode is a battery member that enables charging and discharging of the secondary battery by occluding and releasing metal ions responsible for battery reaction such as lithium ions. And as an electrode, the positive electrode by which the positive electrode compound material layer was normally formed on the electrical power collector, and the negative electrode by which the negative electrode composite material layer was formed on the electrical power collector are mentioned.

<< Current collector >>
As the current collector, an electrically conductive and electrochemically durable material is used. Specifically, as the current collector, for example, a current collector made of a metal material such as iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, or platinum can be used. In addition, the said material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Among these, a thin film made of aluminum is preferable as the current collector used for manufacturing the positive electrode, and a thin film made of copper is preferable as the current collector used for manufacturing the negative electrode.

<< Method for Forming Electrode Compound Layer >>
The electrode mixture layer is not particularly limited, and for example, the electrode slurry composition (positive electrode slurry composition, negative electrode slurry composition) described above is applied in the same manner as the adhesive layer forming method described above. It can form on a collector through a process and a drying process.
Note that after the drying step, the electrode mixture layer may be subjected to pressure treatment using a die press or a roll press. The adhesion between the electrode mixture layer and the current collector can be improved by the pressure treatment. Moreover, when an electrode compound-material layer contains a curable polymer, it is preferable to harden the said polymer after formation of an electrode compound-material layer.

<Electrolyte>
As the electrolytic solution, an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is usually used. For example, when the non-aqueous secondary battery is a lithium ion secondary battery, a lithium salt is used as the supporting electrolyte. Examples of the lithium salt include LiPF ₆ , LiAsF ₆ , LiBF ₄ , LiSbF ₆ , LiAlCl ₄ , LiClO ₄ , CF ₃ SO ₃ Li, C ₄ F ₉ SO ₃ Li, CF ₃ COOLi, (CF ₃ CO) ₂ NLi , (CF ₃ SO ₂ ) ₂ NLi, (C ₂ F ₅ SO ₂ ) NLi, and the like. Of these, LiPF ₆ , LiClO ₄ , and CF ₃ SO ₃ Li are preferable, and LiPF ₆ is particularly preferable because it is easily dissolved in a solvent and exhibits a high degree of dissociation. In addition, electrolyte may be used individually by 1 type and may be used combining two or more types by arbitrary ratios. Usually, the lithium ion conductivity tends to increase as the supporting electrolyte having a higher degree of dissociation is used, and therefore the lithium ion conductivity can be adjusted depending on the type of the supporting electrolyte.

The organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte. For example, dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC) ), Carbonates such as butylene carbonate (BC) and ethyl methyl carbonate (EMC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; including sulfolane and dimethyl sulfoxide Sulfur compounds; etc. are preferably used. Moreover, you may use the liquid mixture of these solvents. Among them, it is preferable to use carbonates because they have a high dielectric constant and a wide stable potential region, and it is more preferable to use a mixture of ethylene carbonate and ethyl methyl carbonate.
Further, known additives such as vinylene carbonate (VC), fluoroethylene carbonate (FEC), and ethyl methyl sulfone may be added to the electrolytic solution.
In addition, although the organic solvent used for electrolyte solution differs normally from the organic solvent contained in the composition for batteries stored according to the storage method of this invention, the same organic solvent may be sufficient.

<Assembly method>
The secondary battery can be manufactured using a known assembly method without any particular limitation. Specifically, in the secondary battery, for example, as described above, an electrode and a separator are wound into a battery shape as needed via an adhesive layer, folded into a battery container, and the battery container is electrolyzed. It can be manufactured by injecting and sealing the liquid. Here, in order to prevent an increase in internal pressure of the secondary battery, overcharge / discharge, etc., an overcurrent prevention element such as a fuse or PTC element, an expanded metal, a lead plate, etc. may be provided as necessary. Good. The shape of the secondary battery may be any of a coin type, a button type, a sheet type, a cylindrical type, a square type, a flat type, and the like.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the following description, “%” and “part” representing amounts are based on mass unless otherwise specified.
Moreover, although the following example demonstrates the case where a battery composition is a binder composition used for formation of a contact bonding layer as an example, this invention is not limited to this.
And the viscosity of the battery composition, the surface roughness of the inner wall of the storage container, the porosity in the storage of the battery composition, the oxygen concentration in the void, the moisture concentration in the void, the process adhesion between the battery members, the secondary battery The high-temperature cycle characteristics and container safety during storage were calculated, measured and evaluated by the following methods.

<Viscosity of battery composition>
The viscosity (mPa · s) of the battery composition was measured as a viscosity at a shear rate of 1 s ⁻¹ using a B-type viscometer (product name “TVB-25” manufactured by Toki Sangyo). Specifically, under the environment of a temperature of 23 ° C., the measurement of the viscosity of the battery composition is started while applying a shearing force at a rotation speed of 60 rpm of a B-type viscometer to the battery composition. The value after 2 seconds was adopted and evaluated. The results are shown in Table 1.

<Surface roughness of container inner wall>
The surface roughness of the inner wall of the container used for storage of the battery composition was calculated as the arithmetic average roughness Ra (μm) using a non-contact surface shape measuring instrument (product name “New View 5000” manufactured by Zygo). It was measured. Measurement conditions were as follows: objective lens: 10 times, measurement region: 1.82 mm × 1.36 mm. The results are shown in Table 1.

<Porosity in storage of battery composition>
The porosity (volume%) in the container when the battery composition is stored is expressed by the following formula (4):
Porosity (volume%) = volume of void / inner volume of container × 100
= (Inner volume of container-volume occupied by battery composition in container) / Inner volume of container × 100 (4)
Can be expressed as Here, since the volume ratio of the container and the gap in the above formula (4) can be obtained from the height ratio of the container and the gap in this embodiment, each ruler (which conforms to JIS) is used. The porosity was calculated by measuring the height. Here, regarding the measurement of the height, specifically, a ruler was inserted from the opening of the container filled with the battery composition, the ruler was inserted to the bottom of the container, and then the ruler was extracted from the container. And the height which the battery composition occupies in the container from the container bottom part was measured by measuring the part which the battery composition adhered to the ruler extracted from the container. And the following formula (5):
Porosity (volume%) = (container height−height occupied by the battery composition in the container from the container bottom) / container height × 100 (5)
The porosity was calculated according to The results are shown in Table 1.

<Oxygen concentration in the void>
The oxygen concentration (mass%) in the space | gap part of a storage container was performed in the environment blocked | interrupted with external air which performed the filling operation | work to the container of the composition for batteries. Specifically, an oxygen concentration meter (product name “OX-102” manufactured by Yokogawa Electric Corporation) was used to measure the oxygen concentration in the void of the container immediately before filling with the battery composition. Here, the oxygen concentration in the environment shut off from the outside air was kept constant before and after the battery composition filling operation. Further, the oxygen concentration in the voids was kept constant even after hermetically storing for a certain period. Table 1 shows the results measured immediately before filling the battery composition.

<Moisture concentration in the void>
The water concentration (mass ppm) in the void of the storage container was measured in an environment where the battery composition was filled into the container and was blocked from the outside air. Specifically, a vial bottle (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was placed in the void portion of the container immediately before filling with the battery composition, and the gas in the void portion was collected. And the water | moisture-content density | concentration of the extract | collected space | gap part was measured using the Karl Fischer moisture meter (the Mitsubishi Chemical make, model number "CA-200"). Here, the moisture concentration in the environment shut off from the outside air was kept constant throughout the battery composition filling operation. In addition, the moisture concentration in the gap was kept constant even after being sealed and stored for a certain period. Table 1 shows the results measured immediately before filling the battery composition.

<Process adhesion between battery members>
Process adhesion between battery members was evaluated by calculating peel strength.
Specifically, the prepared laminate including the positive electrode and the separator and the laminate including the negative electrode and the separator were each cut into a width of 10 mm to obtain a test piece. Next, the obtained test piece was pressed under conditions of a temperature of 120 ° C. and a pressure of 0.35 MPa for 8 seconds to obtain an integrated product in which the electrode and the separator were integrated. Then, the cellophane tape was affixed on the surface of the electrode compound-material layer with the surface of the electrode compound-material layer side of an electrode (positive electrode or negative electrode) facing down. At this time, a cellophane tape defined in JIS Z1522 was used. The cellophane tape was fixed on a horizontal test bench. Thereafter, the stress was measured when one end of the separator was pulled vertically upward at a pulling speed of 50 mm / min and peeled off. This measurement was performed three times for each of the laminate including the positive electrode and the separator and the laminate including the negative electrode and the separator for a total of 6 times, and the average value of the stress was obtained, and the average value was defined as the peel strength (N / m). .
And it evaluated as the process adhesiveness between battery members by the following references | standards using the calculated peel strength. Higher peel strength means higher process adhesion between battery members. The results are shown in Table 1.
Evaluation A: Peel strength is 2.0 N / m or more Evaluation B: Peel strength is 1.0 N / m or more and less than 2.0 N / m Evaluation C: Peel strength is 0.6 N / m or more and less than 1.0 N / m Evaluation D : Peel strength is less than 0.6 N / m

<High-temperature cycle characteristics of secondary batteries>
The manufactured 800 mAh wound cell lithium ion secondary battery was allowed to stand for 24 hours in an environment at a temperature of 25 ° C. Thereafter, in an environment at a temperature of 25 ° C., an initial charge / discharge operation was performed in which the battery was charged to a voltage of 4.35 V at a rate of 0.1 C and discharged to a voltage of 2.75 V at a rate of 0.1 C. Then, the initial capacity C0 of the lithium ion secondary battery after the initial charge / discharge was measured.
Next, charging and discharging were repeated 1000 cycles under the same conditions as described above in an environment at a temperature of 60 ° C. And the capacity | capacitance C1 of the lithium ion secondary battery after 1000 cycles was measured.
Then, from the measured C0 and C1, the capacity retention ratio ΔC is expressed by the following formula (6):
ΔC = C1 / C0 × 100 (%) (6)
Calculated according to The higher the capacity retention ratio ΔC, the better the high-temperature cycle characteristics of the lithium ion secondary battery, and the longer the battery life. The results are shown in Table 1.
Evaluation A: Capacity maintenance rate is 84% or more Evaluation B: Capacity maintenance rate is 80% or more and less than 84% Evaluation C: Capacity maintenance rate is 75% or more and less than 80% Evaluation D: Capacity maintenance rate is less than 75%

<Container safety during storage>
A stirring device 2 used in a container safety test during storage is shown in FIG. First, the storage container 8 filled with the battery composition was fixed to the holding unit 18 and set in the stirring device 2. Next, the upper surface 6 of the storage container 8 is rotated 15 times toward the back side in FIG. 1 (in other words, the counterclockwise direction with respect to the rotation shaft 16 when viewed from the motor 14 side), and The stirring operation for rotating the bottom surface 4 15 times toward the back side in FIG. 1 (in other words, the clockwise direction when viewed from the motor 14 side) is defined as one pass, and the stirring operation is performed for 32 passes. went. In addition, the angle θ formed by the axis 10 shown in FIG. 1 and the horizontal axis 12 was set to 70 °, and the same stirring operation as described above was performed for 32 passes. Then, the container 8 for storage was left still, and the direction orthogonal to the axis 10 in the container 8 for storage, ie, the length of the container in the width direction, was measured. And the following formula (7):
Vessel expansion degree (%) = (length in the width direction of the container after stirring−length in the width direction of the container before stirring) ÷ length in the width direction of the container before stirring × 100 (7)
According to the above, the degree of container expansion (%) was calculated. And the container safety | security at the time of storage was evaluated from the calculated container expansion | swelling degree according to the following references | standards. It shows that container safety | security is so high that the value of a container expansion degree is small. The results are shown in Table 1.
Evaluation A: Container expansion is 5% or less Evaluation B: Container expansion is more than 5% and 10% or less Evaluation C: Container expansion is more than 10% and 20% or less Evaluation D: Container expansion is more than 20%

Example 1
<Preparation of battery composition>
<< Preparation of polymer >>
In an autoclave equipped with a stirrer, 240 parts of ion exchange water, 2.5 parts of sodium alkylbenzene sulfonate as an emulsifier, 36.2 parts of acrylonitrile as a polymerizable monomer, 0.45 t-dodecyl mercaptan as a chain transfer agent Parts in this order, and the inside was purged with nitrogen. Then, 63.8 parts of 1,3-butadiene as a polymerizable monomer was injected, 0.25 part of ammonium persulfate as a polymerization initiator was added, The polymerization reaction was carried out at a reaction temperature of 40 ° C. A copolymer of acrylonitrile and 1,3-butadiene was obtained. The polymerization conversion rate was 85%.
Ion exchange water was added to the obtained copolymer to obtain a solution in which the total solid content concentration was adjusted to 12% by mass. 400 mL of the obtained solution (total solid content 48 g) was put into an autoclave with a stirrer having a volume of 1 L, and nitrogen gas was allowed to flow for 10 minutes to remove dissolved oxygen in the solution. Then, palladium acetate as a hydrogenation reaction catalyst 75 mg was dissolved in 180 mL of ion exchange water to which 4 times mole of nitric acid had been added with respect to palladium (Pd) and added. After replacing the system twice with hydrogen gas, the contents of the autoclave are heated to 50 ° C. under pressure with hydrogen gas up to 3 MPa, and a hydrogenation reaction (first stage hydrogenation reaction) is performed for 6 hours. It was.
Next, the autoclave was returned to atmospheric pressure, and further 25 mg of palladium acetate as a hydrogenation reaction catalyst was dissolved in 60 mL of ion-exchanged water added with 4-fold mol of nitric acid with respect to Pd and added. After the inside of the system was replaced twice with hydrogen gas, the autoclave contents were heated to 50 ° C. with hydrogen gas pressure up to 3 MPa, and the hydrogenation reaction (second stage hydrogenation reaction) was performed for 6 hours. It was.
Thereafter, the contents were returned to room temperature, the inside of the system was changed to a nitrogen atmosphere, and then concentrated using an evaporator until the solid content concentration became 40% to obtain an aqueous dispersion of the copolymer.
In addition, an aqueous dispersion of the copolymer was dropped into methanol to coagulate the copolymer, and then the coagulated product of the copolymer was vacuum dried in an environment at a temperature of 60 ° C. for 12 hours to obtain a copolymer. It was.
<< Preparation of binder composition >>
A binder composition as a battery composition is prepared by mixing the copolymer obtained above with acetone as an organic solvent so that the solid content concentration of the copolymer in acetone is 10% by mass. Was prepared.
And the viscosity in shear rate 1s- ¹ of the battery composition (binder composition) prepared by the above-mentioned method was measured. The results are shown in Table 1.

<Storage of battery composition>
The binder composition obtained above was filled into a resin container (product name “22AT-2”, manufactured by Sekisui Molding Co., Ltd.) made of polyethylene for both the outer wall and the inner wall so that the porosity was 10% by volume. Prior to the filling, a polyethylene resin container is filled with nitrogen gas having a predetermined oxygen concentration and moisture concentration in advance, the oxygen concentration in the container is 0.7 mass%, and the moisture concentration is 3 mass ppm. It was adjusted to.
Here, the surface roughness Ra of the inner wall of the resin container used for storage was measured by the method described above. Moreover, the porosity in storage of the battery composition, the oxygen concentration in the storage container, and the moisture concentration in the storage container were also measured by the above-described methods. The results are shown in Table 1.
And the said container was sealed and the binder composition was stored for 9 months in the environment of temperature 25 degreeC. It was confirmed that the oxygen concentration and water concentration adjusted as described above were unchanged before and after storage.

<Preparation of slurry composition for adhesive layer>
100 parts of α-alumina particles (primary particle size: 0.85 μm) produced by the Bayer method as non-conductive particles and 0.5 parts of cyanoethylated pullulan (substitution rate 80%) as a dispersant are mixed to obtain a solid content. Acetone was added so that the concentration was 25% by mass. And the slurry composition before dispersion | distribution was obtained by further mixing the said mixture.
Next, using the media-less disperser (product name “In-line pulverizer MKO” manufactured by IKA), the slurry composition before dispersion obtained above was subjected to a peripheral speed of 10 m / second and a flow rate of 200 L / hour. 1 pass was distributed under the conditions of Thereafter, using a classifier (manufactured by Accor, product name “Slurry Screener”), only coarse particles were removed while classification to obtain a slurry composition after dispersion.
Subsequently, the blended amount of the binder composition becomes 20 parts by mass corresponding to the solid content per 100 parts by mass of the non-conductive particles of the slurry composition after dispersion and the binder composition after being stored for 9 months as described above. The mixture was obtained by mixing in a stirring vessel. As the stirring and mixing method, the same stirring and mixing method as that used in the container safety test during storage described above was used. And the slurry composition for contact bonding layers of 20% of solid content concentration was obtained by diluting the said mixture with acetone.

<Preparation of separator with adhesive layer>
The adhesive layer applied by applying the slurry composition for an adhesive layer obtained above on the surface of a separator (made of polypropylene, product name “Celgard 2500”) and heating for 3 minutes in an environment at a temperature of 50 ° C. The slurry composition for use was dried. The same operation was performed on the other surface of the separator to obtain a separator with an adhesive layer provided with adhesive layers on both sides with a thickness of 3 μm on one side.

<Preparation of positive electrode>
<< Preparation of slurry composition for positive electrode >>
100 parts LiCoO ₂ (volume average particle diameter: 12 μm) as the positive electrode active material, ₂ parts acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., product name “HS-100”) as the conductive material, and polyvinylidene fluoride (PVDF, The product name “# 7208” manufactured by Kureha Co., Ltd.) was mixed with 2 parts corresponding to the solid content and N-methylpyrrolidone (NMP) as a solvent to make the total solid content concentration 70%. These were mixed by a planetary mixer to prepare a positive electrode slurry composition.
<< Formation of Positive Electrode Mixture Layer >>
The positive electrode slurry composition was applied on an aluminum foil (thickness: 20 μm) as a current collector with a comma coater so that the film thickness after drying was about 150 μm and dried. This drying was performed by conveying the aluminum foil coated with the slurry composition through an oven in an environment at a speed of 0.5 m / min and a temperature of 60 ° C. for 2 minutes. Thereafter, heat treatment was performed for 2 minutes in an environment at a temperature of 120 ° C. to obtain a positive electrode original fabric before pressing. And the positive electrode raw material before press which was obtained was rolled by the roll press, and the positive electrode after the press whose thickness of a positive electrode compound-material layer is 80 micrometers was obtained (single-sided positive electrode).

<Production of negative electrode>
<< Preparation of binder composition for negative electrode >>
In a 5 MPa pressure vessel equipped with a stirrer, 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid and 63.5 parts of styrene as a polymerizable monomer, 0.4 part of sodium dodecylbenzenesulfonate as an emulsifier, ion exchange After adding 150 parts of water and 0.5 part of potassium persulfate as a polymerization initiator and stirring sufficiently, the mixture was heated to 50 ° C. to initiate polymerization. When the polymerization conversion rate reached 96%, the reaction was stopped by cooling to obtain a mixture containing a particulate binder composition (styrene-butadiene copolymer) as a negative electrode binder composition. After adjusting the pH to 8 by adding 5% aqueous sodium hydroxide solution to the mixture containing the particulate binder composition, unreacted monomers were removed from the mixture containing the particulate binder composition by heating under reduced pressure. Then, the aqueous dispersion containing the binder composition for negative electrodes was obtained by cooling to 30 degrees C or less.

<< Preparation of slurry composition for negative electrode >>
100 parts of artificial graphite (average particle size: 15.6 μm), 1 part of a 2% aqueous solution of carboxymethylcellulose sodium salt (manufactured by Nippon Paper Industries Co., Ltd., product name “MAC350HC”) as a viscosity modifier, with ion exchange water After adjusting to a solid content of 68%, the mixture was mixed for 60 minutes in an environment at a temperature of 25 ° C. Furthermore, after adjusting to 62% of solid content concentration with ion-exchange water, it mixed for 15 minutes in the environment of temperature 25 degreeC further. In the above mixed liquid, 1.5 parts of the particulate binder composition obtained above in solid content equivalent amount and ion-exchanged water are added, adjusted so that the final solid content concentration is 52%, and further mixed for 10 minutes. Thus, a slurry mixture was obtained. And the slurry composition for negative electrodes with sufficient fluidity | liquidity was prepared by carrying out the defoaming process of the obtained slurry mixture under reduced pressure.
<< Formation of Negative Electrode Composite Layer >>
The slurry composition for negative electrode obtained above is applied on a copper foil (thickness: 20 μm), which is a current collector, with a comma coater so that the film thickness after drying is about 150 μm and dried. It was. This drying was performed by transporting the copper foil coated with the slurry composition in an oven in an environment at a speed of 0.5 m / min and a temperature of 60 ° C. over 2 minutes. Thereafter, heat treatment was performed for 2 minutes in an environment at a temperature of 120 ° C. to obtain a negative electrode raw material before pressing. And the negative electrode raw material before the obtained press was rolled with the roll press, and the negative electrode after the press whose thickness of a negative electrode compound-material layer is 80 micrometers was obtained (single-sided negative electrode).

<Manufacture of lithium ion secondary batteries>
The pressed positive electrode obtained above was cut into 49 cm × 5 cm. Moreover, the separator with an adhesive layer cut out to 120 cm × 5.5 cm was arranged on the positive electrode mixture layer of the positive electrode after the cut out. Furthermore, the negative electrode after pressing obtained above was cut into 50 cm × 5.2 cm, and the negative electrode after pressing was cut out with the adhesive layer so that the negative electrode mixture layer and the adhesive layer surface of the separator with the adhesive layer faced each other. By disposing on the separator with an adhesive, a laminate composed of a positive electrode / a separator with an adhesive layer / a negative electrode was obtained. The obtained laminate was wound with a winding machine to obtain a wound body. At this time, an adhesive layer surface is disposed on the outermost periphery of the obtained wound body. Further, the wound body was pressed into a flat body under the conditions of a temperature of 120 ° C., a pressure of 0.35 MPa, and 8 seconds. Next, the flat body is wrapped with an aluminum packaging material exterior as a battery exterior, and an electrolytic solution (solvent: ethylene carbonate (EC) / diethyl carbonate (DEC) / vinylene carbonate (VC)) is contained in the aluminum packaging material exterior. = 68.5 / 30 / 1.5 volume ratio, electrolyte: LiPF _{6 at a} concentration of 1 M was injected so that no air remained. Then, the opening of the aluminum packaging material sheath into which the electrolyte solution has been injected is hermetically closed with a heat seal at a temperature of 150 ° C., and the aluminum packaging material sheath and the flat body wrapped in the packaging material sheath are heated at a temperature of 100 ° C. The lithium ion secondary battery of the 800 mAh wound type cell was manufactured by pressing on condition of pressure 1.0MPa and 2 minutes.

(Example 2)
The adhesive layer polymer, the binder composition, and the adhesive layer were prepared in the same manner as in Example 1 except that the solid content concentration of the copolymer was adjusted to 13% by mass when preparing the binder composition. Slurry composition, separator with adhesive layer, positive electrode, negative electrode, and lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
The adhesive layer polymer, the binder composition, and the adhesive layer were prepared in the same manner as in Example 1 except that the solid content concentration of the copolymer was adjusted to 8% by mass when preparing the binder composition. Slurry composition, separator with adhesive layer, positive electrode, negative electrode, and lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

Example 4
In the same manner as in Example 1 except that the solid content concentration of the copolymer was adjusted to 13.5% by mass during the preparation of the binder composition, the adhesive layer polymer, the binder composition, A slurry composition for an adhesive layer, a separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
In the preparation of the binder composition, the same method as in Example 1 except that toluene was used as the organic solvent, the adhesive layer polymer, the binder composition, the adhesive layer slurry composition, the separator with the adhesive layer, A positive electrode, a negative electrode, and a lithium ion secondary battery were manufactured.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
In the preparation of the binder composition, the same method as in Example 1 except that xylene was used as the organic solvent, the adhesive layer polymer, the binder composition, the adhesive layer slurry composition, the separator with the adhesive layer, A positive electrode, a negative electrode, and a lithium ion secondary battery were manufactured.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
The adhesive layer polymer, the binder composition, and the adhesive layer slurry composition were the same as in Example 1 except that the porosity was 6% by volume when the battery composition was stored. A separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 8)
A polymer for the adhesive layer, a binder composition, and a slurry composition for the adhesive layer in the same manner as in Example 1 except that the porosity was 43% by volume during storage of the battery composition. A separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

Example 9
In the same manner as in Example 1 except that the oxygen concentration in the container was adjusted to 0.9 mass% by using nitrogen having an oxygen concentration of 0.9 mass% during storage of the battery composition, A polymer for the adhesive layer, a binder composition, a slurry composition for the adhesive layer, a separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 10)
In the same manner as in Example 1 except that the oxygen concentration in the container was adjusted to 1.0 mass% by using nitrogen having an oxygen concentration of 1.0 mass% during storage of the battery composition, A polymer for the adhesive layer, a binder composition, a slurry composition for the adhesive layer, a separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 11)
In the same manner as in Example 1 except that the moisture concentration in the container was adjusted to 90 mass ppm by using nitrogen having a moisture concentration of 90 mass ppm during storage of the battery composition, A coalescence, a binder composition, a slurry composition for an adhesive layer, a separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

Example 12
In the same manner as in Example 1 except that the moisture concentration in the container was adjusted to 70 ppm by using nitrogen having a moisture concentration of 70 ppm by weight when storing the battery composition, A coalescence, a binder composition, a slurry composition for an adhesive layer, a separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
The adhesive layer polymer, the binder composition, and the adhesive layer slurry composition were prepared in the same manner as in Example 1 except that N-methylpyrrolidone (NMP) was used as the organic solvent when preparing the binder composition. A separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
A polymer for the adhesive layer, a binder composition, and a slurry composition for the adhesive layer in the same manner as in Example 1 except that the porosity was 1% by volume when the battery composition was stored. A separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
A polymer for the adhesive layer, a binder composition, and a slurry composition for the adhesive layer in the same manner as in Example 1 except that the porosity was 55% by volume during storage of the battery composition. A separator with an adhesive layer, a positive electrode, a negative electrode, and a lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
The adhesive layer polymer, the binder composition, and the adhesive layer were prepared in the same manner as in Example 1 except that the solid content concentration of the copolymer was adjusted to 7% by mass when preparing the binder composition. Slurry composition, separator with adhesive layer, positive electrode, negative electrode, and lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 5)
The adhesive layer polymer, the binder composition, and the adhesive layer were prepared in the same manner as in Example 1 except that the solid content concentration of the copolymer was adjusted to 14% by mass when preparing the binder composition. Slurry composition, separator with adhesive layer, positive electrode, negative electrode, and lithium ion secondary battery were produced.
Measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

From Table 1, Comparative Example 1 using an organic solvent having a boiling point exceeding 150 ° C., Comparative Example 4 using a battery composition having a viscosity at a shear rate of 1 s ⁻¹ of less than 100 mPa · s / over 1000 mPa · s. 5 and an organic solvent having a boiling point of 30 ° C. or more and 150 ° C. or less, and the viscosity is 100 mPa · s or more and 1000 mPa · s or less, with respect to Comparative Example 3 in which the porosity during storage was over 50% by volume In Examples 1 to 12 in which the battery composition was filled and stored so that the porosity was 5% by volume or more and 50% by volume or less, high process adhesion, high cycle characteristics, and high container stability during storage were combined. did.
Moreover, in Comparative Example 2 in which the porosity during storage was less than 5% by volume, the container stability during storage was higher than in Examples 1-12 in which the porosity was 5% by volume or more and 50% by volume or less. Sexually deteriorated.

  According to the present invention, even when the battery composition used for manufacturing the battery member and the secondary battery is stored for a long period of time, the container can be safely stored without being deformed, and the battery. It is possible to provide a method for storing a battery composition that can maintain good process adhesion between members and cycle characteristics of a secondary battery.

2 Stirring device 4 Bottom surface 6 Top surface 8 Container 10 for storage Axis 12 Horizontal shaft 14 Motor 16 Rotating shaft 18 Holding part

Claims (5)

A method for storing a composition for a non-aqueous secondary battery, wherein the composition for a non-aqueous secondary battery is stored in a container,
The composition for a non-aqueous secondary battery includes a polymer and an organic solvent,
The boiling point of the organic solvent is 30 ° C. or more and 150 ° C. or less,
The non-aqueous secondary battery composition has a viscosity at a shear rate of 1 s ⁻¹ of 100 mPa · s to 1000 mPa · s, and
The volume ratio (void ratio) of the void portion excluding the volume occupied by the composition for a non-aqueous secondary battery in the container from the inner volume of the container with respect to the inner volume of the container is 5 volume% or more and 50 volume% or less. Is,
The storage method of the composition for non-aqueous secondary batteries. The oxygen concentration in the void is 1.0 mass% or less,
The storage method of the composition for non-aqueous secondary batteries of Claim 1. The water content in the void is 100 mass ppm or less,
The storage method of the composition for non-aqueous secondary batteries of Claim 1 or 2. The inner wall of the container is a resin;
The storage method of the composition for non-aqueous secondary batteries of any one of Claims 1-3. The absolute value | SP _diff | = | SP _p −SP _s | of the difference between the solubility parameter SP _p of the polymer and the solubility parameter SP _s of the organic solvent is 1.5 or more and 6.0 or less.
The storage method of the composition for non-aqueous secondary batteries of any one of Claims 1-4.

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