JP2013161725A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery having excellent charge/discharge characteristics in repeated charging and discharging.SOLUTION: The battery comprises: an electrode for a battery, which contains a vinyl chloride polymer having an average particle diameter of 0.05-1.0 μm and/or a vinyl chloride copolymer having an average particle diameter of 0.05-1.0 μm, an active material, and a collector; and an electrolyte.

Description

  The present invention relates to a battery using a battery electrode containing a vinyl chloride polymer and / or a vinyl chloride copolymer, an active material, and a current collector.

  In recent years, batteries have been used for various purposes. In recent years, the spread of secondary batteries has become remarkable among the batteries. As an application in which the secondary battery is used, there is a hybrid type automobile, which has been remarkably spread. Furthermore, it is predicted that plug-in hybrid systems or electric vehicles will be widely used in the future. Electric bicycles have also begun to spread. Furthermore, the spread of mobile terminals such as mobile phones, notebook computers, and PDAs has become remarkable. The spread of power tools such as electric tools is also remarkable. In addition, smart grids, especially power control systems for home use, have begun to spread. Secondary batteries are used for these power sources, and recently, lithium ion secondary batteries are frequently used.

  A battery is basically composed of an electrolyte, an electrode in which a positive electrode and a negative electrode active material, and a current collector are bound, and a separator.

  In the applications listed above, batteries, particularly secondary batteries, are required to be reduced in size, weight, thickness, and performance. In order to improve the performance of the battery, it is important to improve the performance of each member used in the battery, but it is considered that the performance improvement of the electrode is also an important characteristic. Regarding the electrode, in addition to the influence of the active material or the current collector, the influence of the active material or the polymer material serving as a binder for binding the active material and the current collector is also important. Usually, this binder consists of a composition which uses a polymer for water or an organic solvent as a medium, and applies the slurry which mixed the said composition with the active material etc. to an electrical power collector, Then, an electrode is manufactured by drying. Here, as binders contained in the aqueous slurry, styrene / butadiene rubbers (SBR) using styrene, butadiene, acrylonitrile and the like as raw materials are widely known. In the solvent system, fluorine resins such as polyvinylidene fluoride (PVDF) are widely known. Electrodes and batteries formed using these binders are known (for example, Patent Documents 1 and 2).

  However, a lithium ion secondary battery using an electrode formed by using a slurry containing a water-based SBR or a solvent-based fluororesin as a binder has a problem that the battery performance deteriorates during repeated charge and discharge. . In the case of repeated charge and discharge, it is known that the volume of the active material repeats expansion and contraction. In the slurry containing the binder used so far, the active materials and the active material and the current collector Is not sufficient, and peeling between the active materials and between the active material and the current collector is observed. Thereby, it is thought that the performance fall of a battery arises in the case of charging / discharging repeatedly.

  In addition, in a lithium ion secondary battery using an electrode formed by using a slurry containing polyvinylidene fluoride as a binder, polyvinylidene fluoride reacts with water present in the electrode solution, the positive electrode active material or the negative electrode active material. In some cases, hydrogen fluoride gas is generated, which causes serious deterioration in battery performance.

  In order to solve these problems, a lithium ion secondary battery using an electrode formed by using a slurry containing a vinyl chloride polymer as a binder is disclosed (for example, Patent Document 3).

  However, as in the case of using polyvinylidene fluoride as a binder, a slurry is prepared by dissolving a vinyl chloride polymer in a solvent like N-methylpyrrolidone and mixing with an active material or the like.

  The solvent used here is due to environmental hygiene problems, and when such a solvent-based binder is used, the electrode coating equipment must have an explosion-proof structure, and further an exhaust gas treatment equipment is required. . For this reason, in recent years, the use tends to be avoided.

  Under such circumstances, the battery is composed of an electrode formed using a slurry that is a water-based binder and has sufficient binding properties between active materials and between the active material and a current collector, and is repeatedly charged and discharged. In particular, a battery having excellent charge / discharge cycle characteristics has been desired.

JP-A-5-226004 Japanese Patent Laid-Open No. 7-296816 JP 2000-348729 A

  The present invention has been made in view of the above problems, and its object is to provide a battery that uses a battery electrode manufactured using a water-based binder and that does not deteriorate battery performance during repeated charge and discharge. There is to do.

  As a result of intensive studies to solve the above problems, the present inventors have surprisingly found that a battery composed of an electrode formed from a slurry containing a latex containing a specific polymer is repeatedly charged and discharged. At the same time, the inventors have newly found that the battery performance does not deteriorate, and have completed the present invention. That is, the present invention relates to a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm, an active material, and a current collector. A battery comprising a battery electrode containing a body and an electrolyte.

  Hereinafter, the present invention will be described in detail.

  The battery of the present invention comprises a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm, an active material, and a current collector. It is the battery comprised from the electrode for batteries containing a body, and electrolyte solution.

  The type of the battery of the present invention is not particularly limited, and both a primary battery and a secondary battery are possible, preferably a secondary battery, and more preferably a lithium ion secondary battery.

  The battery electrode constituting the battery of the present invention includes a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm. , Containing an active material and a current collector.

  Here, a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm is obtained by polymerizing a vinyl chloride monomer. A vinyl chloride copolymer having an average particle size of 0.05 to 1.0 μm is obtained by polymerizing a vinyl chloride monomer and another monomer (monomer) copolymerizable therewith. It is done.

  When the average particle size of the vinyl chloride polymer and / or vinyl chloride copolymer is less than 0.05 μm, the resulting latex has a high viscosity. When the average particle size exceeds 1.0 μm, not only the binding properties between the active materials and the active material and the current collector are lowered, but also when the average particle size is increased, the particles are likely to settle in the latex. Latex storage stability deteriorates. In order to maintain the storage stability of the obtained latex and to increase the binding properties between the active materials or between the active material and the current collector, the average particle size is preferably 0.05 to 0.5 μm, 0.2 μm is more preferable.

  A vinyl chloride copolymer having an average particle size of 0.05 to 1.0 μm is used to increase the binding property between active materials and between the active material and a current collector plate, and fatty acid vinyl and / or (meth) acrylic. It preferably contains a structural unit represented by the following general formula (1) and / or general formula (2) derived from an acid ester.

（式中、Ｒ_１は炭素数１〜１７のアルキル基を表す。）

(In the formula, R ₁ represents an alkyl group having 1 to 17 carbon atoms.)

（式中、Ｒ_２は炭素数１〜１８のアルキル基を表し、Ｒ_３は水素又はメチル基を表す。）
ここで、脂肪酸ビニルとしては、例えば、酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、カプロン酸ビニル、カプリル酸ビニル、カプリン酸ビニル、ラウリン酸ビニル、パルミチン酸ビニル、ステアリン酸ビニル等の炭素数２〜１８の脂肪酸のビニルエステル等を挙げることができ、好ましくは酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、カプロン酸ビニル、カプリル酸ビニル、カプリン酸ビニル、ラウリン酸ビニル等の炭素数２〜１２の脂肪酸のビニルエステルであり、より好ましくは酢酸ビニルである。

(In the formula, R ₂ represents an alkyl group having 1 to 18 carbon atoms, and R ₃ represents hydrogen or a methyl group.)
Here, examples of the fatty acid vinyl include 2 to 18 carbon atoms such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl palmitate, and vinyl stearate. Vinyl esters of fatty acids, preferably vinyl acetates of 2 to 12 carbon atoms such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, etc. An ester, more preferably vinyl acetate.

  Examples of (meth) acrylic acid esters include methyl acrylate, propyl acrylate, butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, and n-acrylate. -C1-C18 acrylic acid ester, such as decyl, n-dodecyl acrylate, stearyl acrylate, methyl methacrylate, propyl methacrylate, butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, methacrylic acid Examples thereof include methacrylic acid esters having 1 to 18 carbon atoms such as n-heptyl, n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate and stearyl methacrylate, preferably methyl acrylate, acrylic Propyl acid, butyl acrylate C1-C12 acrylic ester such as n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, n-decyl acrylate, n-dodecyl acrylate, methyl methacrylate , Propyl methacrylate, butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate, etc. 12 methacrylic acid esters, and more preferred are C1-C4 acrylic acid esters such as methyl acrylate, propyl acrylate, and butyl acrylate.

  Monomers that can be copolymerized with vinyl chloride monomers include, for example, the above-mentioned fatty acid vinyls and (meth) acrylic acid esters, olefins such as ethylene, propylene, and butene; methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether, lauryl vinyl ether Alkyl vinyl ethers such as: vinylidene halides such as vinylden chloride; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride and acid anhydrides thereof; styrene , Α-methylstyrene, aromatic vinyl compounds such as divinylbenzene; unsaturated nitriles such as acrylonitrile; crosslinkable monomers such as diallyl phthalate and triallyl isocyanurate, and the like. These can be used alone or in combination of two or more. . The monomer charge composition of these copolymerizable monomers in the vinyl chloride copolymer is not particularly limited, but in order to obtain higher binding properties between the active materials and the active material and the current collector, Further, in order to obtain resistance to electrolytic solution swelling, the content is preferably more than 0% by weight and 50% by weight or less, more preferably more than 0% by weight and 30% by weight or less.

  Moreover, those ratios are particularly limited when a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm are included. is not.

  The vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or the vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm in the battery electrode constituting the battery of the present invention. The amount is not particularly limited, but in order to maintain sufficient binding between the active materials or between the active material and the current collector, to facilitate the flow of electricity, and to improve battery characteristics, the weight of the active material is 100 weight. The vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or the vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm is preferably 0.1 -20 parts by weight, more preferably 0.5-10 parts by weight.

  The active material and the current collector contained in the battery electrode constituting the battery of the present invention are as described later.

  The battery electrode constituting the battery of the present invention includes a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm. It is obtained by applying and drying a slurry for a battery electrode containing latex and an active material on a current collector.

  A vinyl chloride copolymer having an average particle size of 0.05 to 1.0 μm is used to increase the binding property between active materials and between the active material and a current collector plate, and fatty acid vinyl and / or (meth) acrylic. It preferably contains a structural unit represented by the following general formula (1) and / or general formula (2) derived from an acid ester.

（式中、Ｒ_１は炭素数１〜１７のアルキル基を表す。）

(In the formula, R ₁ represents an alkyl group having 1 to 17 carbon atoms.)

（式中、Ｒ_２は炭素数１〜１８のアルキル基を表し、Ｒ_３は水素又はメチル基を表す。）
平均粒子径が０．０５〜１．０μｍである塩化ビニル重合体及び／又は平均粒子径が０．０５〜１．０μｍである塩化ビニル共重合体を含むラテックスは、一般的に、１）塩化ビニル単量体単独、又は塩化ビニル単量体とこれと共重合可能な他のモノマー（単量体）の混合物を水性媒体中で、乳化・分散剤、必要に応じて高級アルコール、連鎖移動剤、粒子径制御剤を用い、さらに水溶性開始剤を用いて乳化重合や播種乳化重合する、２）塩化ビニル単量体単独、又は塩化ビニル単量体とこれと共重合可能な他のモノマー（単量体）の混合物を水性媒体中で、乳化・分散剤、必要に応じて高級アルコール、連鎖移動剤を用い、さらに油溶性開始剤を添加して均質化した後に微細懸濁重合や播種微細懸濁重合する、３）塩化ビニル単量体単独、又は塩化ビニル単量体とこれと共重合可能な他のモノマー（単量体）の混合物を水性媒体中で、水溶性高分子、必要に応じて連鎖移動剤、さらに油溶性開始剤を用いて懸濁重合する等により得られる。これらのうち、重合操作の簡便さ等から乳化重合が好ましい。

(In the formula, R ₂ represents an alkyl group having 1 to 18 carbon atoms, and R ₃ represents hydrogen or a methyl group.)
Latex containing a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm is generally 1) chloride. A vinyl monomer alone or a mixture of a vinyl chloride monomer and another monomer (monomer) copolymerizable therewith in an aqueous medium, emulsifying / dispersing agent, if necessary higher alcohol, chain transfer agent , Emulsion polymerization or seeding emulsion polymerization using a particle size control agent, and further using a water-soluble initiator, 2) vinyl chloride monomer alone, or other monomers copolymerizable with vinyl chloride monomer ( Monomer) mixture in aqueous medium, emulsifying / dispersing agent, using higher alcohol and chain transfer agent if necessary, and adding oil-soluble initiator and homogenizing, then fine suspension polymerization and seeding fine Suspension polymerization 3) Vinyl chloride monomer alone or Is a mixture of vinyl chloride monomer and other monomer copolymerizable with water-soluble polymer, water-soluble polymer, chain transfer agent if necessary, and oil-soluble initiator. It can be obtained by suspension polymerization. Of these, emulsion polymerization is preferred from the standpoint of ease of polymerization.

  The emulsifying / dispersing agent used for the polymerization is not particularly limited, and for example, an anionic surfactant, a nonionic surfactant, a water-soluble polymer and the like are used. Here, examples of the anionic surfactant include alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; alkyl sulfate esters such as sodium lauryl sulfate and sodium tetradecyl sulfate; sodium dioctyl sulfosuccinate and sodium dihexyl sulfosuccinate. Sulfosuccinate; Fatty acid salt such as sodium laurate and semi-cured tallow fatty acid potassium; Disproportionated rosin acid salt such as disproportionated sodium rosinate; Polyoxyethylene lauryl ether sulfate sodium salt, Polyoxyethylene nonyl phenyl ether sulfate sodium Examples thereof include ethoxysulfate salts such as salts; alkane sulfonates; alkyl ether phosphate sodium salts. Examples of nonionic surfactants include polyoxyethylene fatty alcohol ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether; polyoxyethylene octylphenyl ether and polyoxyethylene dodecylphenyl ether. Ethylene alkyl allyl ethers; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan tristearate; polyoxysorbitol fatty acid esters such as polyoxyethylene sorbitol tetraoleate; stearic acid monoglyceride Glycerol fatty acid esters such as oleic acid monodiglyceride; sorbitan monoparimidate, sorbitan trioleate, etc. Sorbitan fatty acid esters and the like. Examples of the water-soluble polymer include alkali metal salts such as polyvinyl alcohol, polyacrylic acid, and polyacrylic acid; and celluloses such as carboxymethyl cellulose and methyl cellulose. The addition timing of the emulsifying / dispersing agent is not particularly limited, and a predetermined amount can be added in advance before the polymerization reaction, but it is preferable to add appropriately according to the growth of the vinyl chloride resin particles. Further, the amount of the emulsifying / dispersing agent is not particularly limited. However, in order to maintain mechanical stability during polymerization and further increase the binding property, 0.5 to 5 parts by weight is preferred.

  Examples of water-soluble initiators used for emulsion polymerization and seeding emulsion polymerization include water-soluble peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide, and potassium perphosphate; Redox initiator combined with a reducing agent such as sodium hydrogen hydride, ammonium sulfite, potassium metabisulfite, ascorbic acid, ferric ion sodium ethylenediaminetetraacetate complex, ferrous pyrophosphate; 2,2-azobis (2- And water-soluble azo compounds such as methylpropionamidine) dihydrochloride. Moreover, there is no restriction | limiting in particular as the addition time of the said water-soluble initiator, It can add previously before superposition | polymerization reaction or can add continuously during superposition | polymerization reaction in order to control reaction rate. There is no restriction | limiting in particular in the addition amount at the time of adding continuously, What is necessary is just to add in the range which does not exceed the slow heating capability of a superposition | polymerization can.

  The higher alcohol used as necessary is not particularly limited, and usually an aliphatic higher alcohol having 8 to 18 carbon atoms or the like is used, and even if used alone, an aliphatic higher alcohol having a different carbon number is used. Alcohol may be mixed and used.

  Moreover, as a chain transfer agent used as needed, what is necessary is just to be able to adjust the polymerization degree of the vinyl chloride polymer and / or vinyl chloride copolymer obtained, for example, trichlorethylene, carbon tetrachloride, etc. Halogen hydrocarbons; mercaptans such as 2-mercaptoethanol, octyl 3-mercaptopropionate and dodecyl mercaptan; aldehydes such as n-butyraldehyde; acetone and the like.

  Furthermore, as a particle diameter control agent used as needed, alkali metal sulfates, such as sodium sulfate and potassium sulfate, are mentioned, for example. In addition, the amount of the particle size control agent added can efficiently control the particle size of the vinyl chloride polymer and / or vinyl chloride copolymer, and the polymerization reaction becomes stable. It is preferable to set it as 100-5000 ppm with respect to a weight, and it is more preferable to set it as 100-3000 ppm. The addition timing of the particle size control agent is not particularly limited, and may be added in advance before the polymerization reaction or may be continuously added during the polymerization reaction in order to control the particle size to a higher degree. .

  Examples of oil-soluble initiators used in fine suspension polymerization and seeding fine suspension polymerization and suspension polymerization include diacyl peroxides such as dilauroyl peroxide and di-3,5,5-trimethylhexanoyl peroxide. Peroxydicarbonates such as diisopropyl peroxydicarbonate and di-2-ethylhexyl peroxydicarbonate; peroxyesters such as t-butyl peroxypivalate and t-butyl peroxyneodecanoate Organic peroxide initiator, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4 And azo initiators such as -dimethylvaleronitrile).

  Although it does not specifically limit as temperature which can superpose | polymerize, in order to superpose | polymerize more and to set it as suitable polymerization time, the range of 10-80 degreeC is preferable, and the range of 30-70 degreeC is further more preferable.

  The completion time of the polymerization reaction is not particularly limited. However, in order to ensure sufficient binding between the active materials and between the active material and the current collector, the polymerization rate of the monomer is polymerized to 60 to 100%. It is preferable to advance the polymerization, and it is more preferable to advance the polymerization to 80 to 100%.

  When unreacted monomer remains in the obtained latex, the monomer may be removed by a monomer strip or the like in order to improve environmental safety.

  The solid content of the latex containing the vinyl chloride polymer and / or the vinyl chloride copolymer is not particularly limited, but the viscosity of the latex is prevented from being increased, and the slurry can be easily mixed to produce a slurry. 70% by weight or less is preferable in order to improve the workability when applying the coating.

  The battery electrode slurry used in the production of the battery electrode constituting the battery of the present invention has a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or an average particle diameter of 0.05 to 1.0. It is prepared by mixing a latex containing a vinyl chloride copolymer having a thickness of 1.0 μm and an active material.

Here, any generally known active material can be used. For example, carbon-based materials such as amorphous carbon, graphite, carbon fluoride, carbon fiber, resin-fired carbon, and graphite whiskers; polymer compounds such as polyacene; conductive organic compounds; silicon that can be alloyed with lithium; tin, etc. The metal etc. are mentioned. Examples of the positive electrode active material include metal oxides such as manganese dioxide, molybdenum trioxide, divanadium pentoxide, and iron oxides; complex oxides including lithium such as LiCoO ₂ , LiMnO ₂ , and LiNiO ₂ ; LiFePO _{4 and the} like A composite metal oxide containing lithium, a transition metal sulfide such as FeS _2, a transition metal oxide such as Cu ₂ V ₂ O _3, a metal fluoride such as NiF _{2, and} a polymer compound such as polyacetylene. These active materials can be used alone or in combination of two or more. In addition, these active materials are generally defined in polarity by the respective potentials of the active material used for one electrode and the active material used for the other electrode, and the active material with the higher potential becomes the positive electrode, The lower active material becomes the negative electrode.

  The battery electrode slurry may contain generally known surfactants, dispersants, water-soluble polymers and the like in order to adjust the viscosity and application workability of the slurry. Moreover, it is preferable that the slurry for battery electrodes of this invention contains an electroconductivity imparting agent, in order to make electroconductivity higher. As the conductivity-imparting agent, for example, conductive carbon such as acetylene black, ketjen black, carbon black, and graphite can be used.

  As a method for producing the battery electrode slurry, a generally known method is used. Specifically, it is manufactured by mixing latex and an active material. The mixing is not particularly limited as long as it is a commonly used mixing apparatus. For example, a ball mill, a homogenizer, an ultrasonic disperser, a planetary mixer, a kneader, or the like can be used.

  A latex containing a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm contained in the battery electrode slurry. The amount of addition is not particularly limited, but the active material 100 is used in order to maintain sufficient binding between the active materials or between the active material and the current collector, to facilitate the flow of electricity, and to improve the battery characteristics. A vinyl chloride polymer having an average particle size of 0.05 to 1.0 μm and / or an average particle size of 0.05 to 1.0 μm as a solid content of the latex with respect to parts by weight. Is preferably added in an amount of 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight.

  The current collector is not limited as long as it is generally used. For example, metal materials such as iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, and platinum are used. Aluminum is preferable for the positive electrode, and copper is preferable for the negative electrode. The shape of the current collector is not particularly limited as long as sufficient battery performance is exhibited. The thickness of the current collector is not particularly limited, but is 1 to 300 μm in order to show good battery characteristics without breaking the current collector due to impact, vibration, or the like. Is preferred.

  If the method for apply | coating the slurry for battery electrodes on a collector for manufacturing the electrode for batteries which comprises the battery of this invention is a general method, there will be no restriction | limiting. For example, methods such as roll coater, gravure, air knife, comma bar, and dipping are used. The coating amount of the battery electrode slurry on the current collector is not particularly limited as long as sufficient battery characteristics are exhibited, but the coating film thickness after drying is 1 to 100 μm. What is necessary is just to apply.

  As a drying method, a method such as standing drying, air drying, hot air drying, infrared drying, or the like is used. The drying temperature and time are not particularly limited, but it is preferable that water is sufficiently volatilized in order to maintain battery characteristics.

  In the present battery, the battery electrode constituting the battery can be configured as a positive electrode or a negative electrode, and the other electrode can be configured as another substance. Examples of the other electrodes include generally known electrodes, for example, electrodes using metals such as metallic lithium and lead. Moreover, this battery can also comprise the battery electrode which comprises this battery as a positive electrode and a negative electrode.

Examples of the electrolytic solution constituting the battery of the present invention include an electrolyte dissolved in a solvent. The electrolyte is not limited as long as it is generally used. For example, LiClO ₄ , LiBF ₆ , LiPF ₆ , LiAsF ₆ , LiSO ₃ CF ₃ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN ( And lithium salts such as SO ₂ CF ₃ ) ₂ . The solvent is not limited as long as it is generally used. For example, carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, and diethyl carbonate; lactones such as γ-butyrolactone; sulfolanes, Nitriles such as acetonitrile; ionic liquids and the like. These can be used alone or in combination of two or more.

  Moreover, a polymer solid electrolyte, a polymer gel electrolyte, etc. can also be used as electrolyte solution.

  The battery of the present invention may be composed of a separator or the like in addition to the battery electrode and the electrolytic solution described above. Here, the separator is not limited as long as it is generally used, and examples thereof include polyolefin nonwoven fabrics such as polyethylene and polypropylene; polyamide nonwoven fabrics; glass fibers and the like.

  The lithium ion secondary battery includes, for example, the above-described battery electrode and electrolyte, and is manufactured by a known method using a separator or the like as necessary. For example, it is a method in which a positive electrode and a negative electrode are overlapped via a separator, wound or folded, put into a battery container, and injected with an electrolytic solution for sealing. As the shape of the battery, a coin type, a button type, a sheet type, a cylindrical type and the like are known.

  The present invention makes it possible to obtain a battery having excellent repetitive charge / discharge characteristics, which has been difficult with conventional batteries, and can be applied to an extremely wide range of industries.

It is a figure which shows the structure of the battery of this invention.

  Next, the present invention will be described in more detail based on the following examples. However, these are examples for helping understanding of the present invention, and the technical scope of the present invention is not limited only to the following examples.

  The following raw materials were used in the examples of the present invention.

<Raw material>
(1) Styrene-Butadiene Rubber (SBR)-Raw Slurry Raw Material TRD2001 made by JSR Corporation
(2) Polyvinylidene fluoride (PVDF) -raw material for solvent-based slurry KF polymer T # 1100 manufactured by Kureha Corporation
(3) Graphite-active material Spherical graphite powder CGB-10 manufactured by Nippon Graphite Industries Co., Ltd.
(4) Lithium cobaltate (LiCoO ₂ ) -active material Cell seed C-5H manufactured by Nippon Chemical Industry Co., Ltd.
(5) Acetylene black-conductivity imparting material Denka black (6) Sodium carboxymethyl cellulose (CMC) manufactured by Denki Kagaku Kogyo Co., Ltd.
Serogen 7A manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
(7) N-methylpyrrolidone (NMP)
Wako Pure Chemical Industries, Ltd. (8) Copper foil-graphite electrode current collector Nippon Test Panel Co., Ltd. C1220P (100 mm x 100 mm x 0.05 mm thickness)
(9) Aluminum foil-current collector for lithium cobaltate electrode 1N30 (width 250 mm x thickness 0.02 mm) manufactured by Nippon Foil Co., Ltd.
The physical properties of the latex were measured by the following method.

<Latex solid content concentration>
1 g of the obtained latex was precisely weighed and then dried for 1 hour in a hot air dryer at 115 ° C. ± 2 ° C. After taking out from the dryer, it cooled in the desiccator for 30 minutes, and solid content concentration was computed from following Formula.

Solid content concentration (%) = 100 × weight after drying (g) / weight of collected latex (g)
<Average particle diameter of vinyl chloride polymer and / or vinyl chloride copolymer>
The average particle size was measured in HRA mode and UPA mode using a Microtrac particle size distribution measuring device (manufactured by Nikkiso Co., Ltd.).

<Measurement of content of vinyl fatty acid in vinyl chloride copolymer>
The content of the structural unit derived from the fatty acid vinyl and / or the (meth) acrylic acid ester in the vinyl chloride copolymer was determined by subjecting the latex to vacuum drying at 40 ° C. for 48 hours, and a Fourier transform infrared spectrophotometer (IRAffinity− 1, manufactured by Shimadzu Corporation), the absorbance ratio between 1430 cm ^−1, which is a characteristic absorption wavelength of a structural unit derived from vinyl chloride and fatty acid vinyl and / or (meth) acrylic ester, and 1730 cm ⁻¹ The fatty acid vinyl and / or (meth) acrylic acid ester content was determined.

<Synthesis of Latex A to E>
Synthesis example 1
In a 2.5 L autoclave, 666 g of deionized water, 600 g (100 parts by weight) of vinyl chloride monomer, 5.4 g (0.027 parts by weight) of 3% by weight aqueous potassium persulfate solution, and 5% by weight of dodecylbenzenesulfone An aqueous sodium acid solution (59.4 g, 0.495 parts by weight) was charged, and the mixture was heated to 66 ° C. while stirring to start emulsion polymerization. From 1 hour after the start of the polymerization reaction to the end of the polymerization reaction, 163.0 g (1.358 parts by weight) of a 5% by weight aqueous sodium dodecylbenzenesulfonate solution and 59.4 g (0.495%) of a 5% by weight aqueous potassium laurate solution. (Part by weight) was continuously added at a constant injection amount. When the polymerization reaction pressure dropped by 0.364 MPa from the saturated vapor pressure of the vinyl chloride monomer at 66 ° C., the polymerization reaction was stopped and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex A. .

  The resulting vinyl chloride polymer latex A had a solid content concentration of 33.5% and an average particle size of 0.08 μm.

Synthesis example 2
In a 2.5 L autoclave, 666 g of deionized water, 600 g (100 parts by weight) of vinyl chloride monomer, 5.4 g (0.027 parts by weight) of 3% by weight aqueous potassium persulfate solution, 5% by weight of dodecylbenzenesulfonic acid Emulsion polymerization was started by charging 59.4 g (0.495 parts by weight) of an aqueous sodium solution and 6.0 g (0.05 parts by weight) of a 5% by weight-sodium sulfate aqueous solution and raising the temperature to 66 ° C. while stirring the mixture. did. From 1 hour after the start of the polymerization reaction to the end of the polymerization reaction, 163.0 g (1.358 parts by weight) of a 5% by weight aqueous sodium dodecylbenzenesulfonate solution and 59.4 g (0.495%) of a 5% by weight aqueous potassium laurate solution. (Part by weight) was continuously added at a constant injection amount. The polymerization reaction was stopped when the polymerization reaction pressure dropped from the saturated vapor pressure of the vinyl chloride monomer at 66 ° C. by 0.364 MPa, and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex B. .

  The resulting vinyl chloride polymer latex B had a solid content concentration of 34.0% and an average particle size of 0.53 μm.

Synthesis example 3
In a 2.5 L autoclave, 666 g of deionized water, 552 g (92.0 parts by weight) of vinyl chloride monomer, 48.0 g (8.0 parts by weight) of vinyl acetate, 5.4 g of a 3% by weight aqueous potassium persulfate solution ( 0.027 parts by weight), and 53.4% (0.695 parts by weight) of a 5% by weight aqueous sodium dodecylbenzenesulfonate solution were charged, and the mixture was heated to 66 ° C. while stirring to initiate emulsion polymerization. From the start of the polymerization reaction to the end of the polymerization reaction, 138.6 g (1.155 parts by weight) of a 5% by weight sodium dodecylbenzenesulfonate aqueous solution and 24.0 g (0.20 parts by weight) of a 5% by weight potassium laurate aqueous solution ) Was continuously added at a constant injection amount. The polymerization reaction was stopped when the polymerization reaction pressure dropped 0.364 MPa from the saturated vapor pressure of the vinyl chloride monomer at 66 ° C., and the unreacted vinyl chloride monomer and unreacted vinyl acetate were recovered, and further 5% by weight 35.4 g (0.295 parts by weight) of an aqueous potassium laurate solution was added and mixed to obtain a vinyl chloride-vinyl acetate copolymer latex C (vinyl chloride copolymer latex).

  The obtained vinyl chloride-vinyl acetate copolymer latex C had a solid content concentration of 36.3% and an average particle size of 0.08 μm. The vinyl acetate content in the vinyl chloride-vinyl acetate copolymer was 6.0% by weight.

Synthesis example 4
666 g of deionized water, 540 g (90.0 parts by weight) of vinyl chloride monomer, 5.4 g (0.027 parts by weight) of a 3% by weight aqueous potassium persulfate solution, and 5% by weight of dodecyl in a 2.5 L autoclave. An aqueous sodium benzenesulfonate solution (59.4 g, 0.495 parts by weight) was charged, and the mixture was heated to 66 ° C. while stirring to start emulsion polymerization. 60 g (10.0 parts by weight) of butyl acrylate was added at a rate of 20 g / hr. Was added continuously over a period of 6 hours. Also, from 1 hour after the start of the polymerization reaction to the end of the polymerization reaction, 163.0 g (1.358 parts by weight) of a 5% by weight aqueous sodium dodecylbenzenesulfonate solution and 59.4 g (0% by weight) of a 5% by weight aqueous potassium laurate solution. .495 parts by weight) was continuously added at a constant injection amount. The polymerization reaction was stopped when the polymerization reaction pressure dropped 0.364 MPa from the saturated vapor pressure of the vinyl chloride monomer at 66 ° C., and the unreacted vinyl chloride monomer and the unreacted butyl acrylate were recovered. A butyl acrylate copolymer latex D (vinyl chloride copolymer latex) was obtained.

  The obtained vinyl chloride-butyl acrylate copolymer latex D had a solid content concentration of 35.5% and an average particle size of 0.09 μm. The butyl acrylate content in the vinyl chloride-butyl acrylate copolymer was 8.8% by weight.

Synthesis example 5
In a 2.5 L autoclave, 1100 g of deionized water, 400 g (100 parts by weight) of vinyl chloride monomer, 64 g (1.6 parts by weight) of 10% by weight aqueous sodium dodecylbenzenesulfonate, 0.64 g of dilauroyl peroxide ( 0.16 parts by weight) and 12 g (3.0 parts by weight) of lauryl alcohol were charged, and the mixture was circulated for 75 minutes by a homogenizer to perform a homogenization treatment. Thereafter, the internal temperature was raised to 66 ° C. to initiate the polymerization reaction. When the polymerization reaction pressure dropped 0.364 MPa from the saturated vapor pressure of the vinyl chloride monomer at 66 ° C., the polymerization reaction was stopped, and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex E. .

  The obtained vinyl chloride polymer latex E had a solid content concentration of 25.5% and an average particle size of 1.15 μm.

Examples 1-7
<Preparation of slurry for battery electrode>
As shown in Table 1, a predetermined amount of latex AD obtained in Synthesis Examples 1 to 4, graphite as an active material, 2% by weight carboxymethylcellulose (CMC), and water were put into a 300 ml polypropylene disposable cup. T. K. Using a homodisper (manufactured by PRIMIX), kneading was performed for 5 minutes while increasing the number of rotations from 350 rpm to 1200 rpm to prepare a battery electrode slurry.

＜電池用電極１〜７の作製＞
バーコーター（ＲＤＳ７５、Ｗｅｂｓｔｅｒ社製）を用い、作製した電池電極用スラリーを、集電板である銅箔上に一定の厚み（１００μｍ）になるように塗布し、１３５℃で１５分熱風乾燥した。

<Preparation of battery electrodes 1-7>
Using a bar coater (RDS75, manufactured by Webster), the prepared battery electrode slurry was applied on a copper foil as a current collector so as to have a constant thickness (100 μm), and dried with hot air at 135 ° C. for 15 minutes. .

  Next, using an electrode punching machine (manufactured by Hosen Co., Ltd.), it was punched into a circle having a diameter of 20.1 mm, and then press molded at a pressure of 3 MPa for 60 seconds. Furthermore, the battery electrodes 1-7 were produced by vacuum-drying at 150 degreeC for 2 hours.

<Evaluation of binding properties>
The peeled state of the active material layer during the press molding described above was visually evaluated and used as a binding index.

  The visual criteria for the peeled state of the active material layer were as follows.

(1) No peeling (excellent binding);
(2) Slight missing on the active material layer surface (good binding);
(3) The active material layer peels off and the underlying current collector plate is slightly exposed;
(4) The active material layer peels off and the underlying current collector plate is completely exposed; ×
The obtained results are shown in Table 1. In any of the obtained battery electrodes, the active material layer was not peeled off and showed excellent binding properties.

<Production of batteries 1 to 7>
The battery shown in FIG. 1 was produced. The battery was produced under an argon gas atmosphere. The battery electrodes 1 to 7 obtained above were used as one electrode (positive electrode, 8).

  As another pole (negative electrode, 5), a metal lithium foil (0.2 mm thickness, manufactured by Honjo Metal Co., Ltd.) cut into a circle having a diameter of 20.1 mm was collected on a current collecting mesh (4, circle with a diameter of 20 mm—made by SUS316). Prepared by rolling with pliers.

  Then, it installed in the container (9) in order of the positive electrode (8), the separator (7), the glass filter (6), the negative electrode (5), and the current collection mesh (4). The positive electrode was stacked so that the active material was in contact with the separator, and the negative electrode was stacked so that lithium was in contact with the glass filter. In addition, an electrolytic solution obtained by dissolving lithium hexafluorophosphate at a concentration of 1 mol / l in a 1: 2 (volume ratio) mixed solvent of ethylene carbonate and dimethyl carbonate was added to the container (9). To the current collecting mesh (4) were put in a state of being immersed. Then, the Teflon (trademark) (trademark registration) seal | sticker (3) was screwed, and the batteries 1-7 were assembled by screwing the lid | cover (2) from it.

<Battery characteristics: Charging / discharging cycle characteristics>
Using the obtained battery, the discharge capacity at the first cycle (unit = mAh / g: per active material (hereinafter referred to as “low current”)) was measured at a constant current method of 0.3 C in a 23 ° C. atmosphere at 0.01 V to 1.5 V. ), And the discharge capacity at the 50th cycle (unit = mAh / g) is measured, and the ratio of the discharge capacity at the 50th cycle to the discharge capacity at the 1st cycle is calculated as a percentage to maintain the capacity. Rate. The larger this value, the smaller the capacity loss due to repeated charge and discharge, and the better the result. In addition, the capacity | capacitance maintenance factor used the average of the measured value of three samples.

  The results are also shown in Table 1. The obtained battery showed an excellent repetitive charge / discharge cycle characteristic by showing a good capacity retention rate.

Comparative Example 1
As shown in Table 2, slurry for battery electrode, battery electrode, and battery were obtained according to the method described in Examples 1 to 7 except that latex A to D was changed to latex E.

得られた電池用電極の結着性を評価したところ、活物質層の部分的な剥離がみられ、結着性は劣っていた。

When the binding property of the obtained battery electrode was evaluated, partial peeling of the active material layer was observed, and the binding property was inferior.

  Furthermore, a charge / discharge cycle test of the obtained battery was performed. The results are also shown in Table 2. The obtained battery had a low capacity retention rate and poor charge / discharge cycle characteristics.

Comparative Example 2
As shown in Table 2, a battery electrode slurry, a battery electrode, and a battery were obtained according to the methods described in Examples 1 to 7 except that the latexes A to D were changed to SBR.

  When the binding property of the obtained battery electrode was evaluated, the active material layer was not peeled off and showed excellent binding property.

  Furthermore, a charge / discharge cycle test of the obtained battery was performed. The results are also shown in Table 2. The obtained battery had a low capacity retention rate and poor charge / discharge cycle characteristics.

Comparative Example 3
As shown in Table 2, the batteries according to the methods described in Examples 1 to 7 except that the latexes A to D were changed to 6.4% by weight-PVDF / NMP solution, CMC was not added, and water was changed to NMP. An electrode slurry, a battery electrode, and a battery were obtained.

  When the binding property of the obtained battery electrode was evaluated, partial peeling of the active material layer was observed, and the binding property was inferior.

  Furthermore, a charge / discharge cycle test of the obtained battery was performed. The results are also shown in Table 2. The obtained battery had a low capacity retention rate and poor charge / discharge cycle characteristics.

Examples 8-14
<Preparation of slurry for battery electrode>
As shown in Table 3, a predetermined amount of latex A to D obtained in Synthesis Examples 1 to 4, lithium cobaltate (LiCoO ₂ ), acetylene black, 2% by weight of carboxymethylcellulose (CMC), and water as active materials. Into a 300 ml polypropylene disposable cup. K. Using a homodisper (manufactured by PRIMIX), kneading was performed for 5 minutes while increasing the number of rotations from 350 rpm to 1200 rpm to prepare a battery electrode slurry.

＜電池用電極８〜１４の作製＞
作製した電池電極用スラリーを、集電板であるアルミ箔上に一定の厚み（１００μｍ）になるように塗布した以外は実施例１〜７に記載の方法に従って電池用電極８〜１４を作製した。

<Preparation of Battery Electrodes 8-14>
Battery electrodes 8 to 14 were produced according to the method described in Examples 1 to 7, except that the produced battery electrode slurry was applied on an aluminum foil as a current collector so as to have a constant thickness (100 μm). .

  The binding property of the obtained battery electrode was evaluated. The obtained results are shown in Table 3. In any of the obtained battery electrodes, the active material layer was not peeled off and showed excellent binding properties.

<Production of batteries 8 to 14>
Batteries were produced according to the methods described in Examples 1 to 7, except that the battery electrodes 1 to 7 in Examples 1 to 7 were changed to the battery electrodes 8 to 14 obtained above.

<Battery characteristics: Charging / discharging cycle characteristics>
Using the obtained battery, the discharge capacity at the first cycle (unit = mAh / g: per active material (hereinafter referred to as “the current”)) was determined by a constant current method of 0.3 C in a 23 ° C. atmosphere at 3.0 V to 4.1 V. The same is true for the electric capacity)) and the discharge capacity (unit = mAh / g) at the 50th cycle, and the ratio of the discharge capacity at the 50th cycle to the discharge capacity at the 1st cycle is calculated as a percentage. It was.

  The results are also shown in Table 3. The obtained battery showed an excellent repetitive charge / discharge cycle characteristic by showing a good capacity retention rate.

Comparative Example 4
As shown in Table 4, slurry for battery electrode, battery electrode, and battery were obtained according to the method described in Examples 8 to 14 except that latex A to D was changed to latex E.

得られた電池用電極の結着性を評価したところ、活物質層の部分的な剥離がみられ、結着性は劣っていた。

When the binding property of the obtained battery electrode was evaluated, partial peeling of the active material layer was observed, and the binding property was inferior.

  Furthermore, a charge / discharge cycle test of the obtained battery was performed. The results are also shown in Table 4. The obtained battery had a low capacity retention rate and poor charge / discharge cycle characteristics.

Comparative Example 5
As shown in Table 4, slurry for battery electrodes, battery electrodes, and batteries were obtained according to the methods described in Examples 8 to 14 except that latexes A to D were changed to SBR.

  When the binding property of the obtained battery electrode was evaluated, the active material layer was not peeled off and showed excellent binding property.

  Furthermore, a charge / discharge cycle test of the obtained battery was performed. The results are also shown in Table 4. The obtained battery had a low capacity retention rate and poor charge / discharge cycle characteristics.

Comparative Example 6
As shown in Table 4, the batteries according to the methods described in Examples 8 to 14 except that the latexes A to D were changed to 6.4% by weight-PVDF / NMP solution, CMC was not added, and water was changed to NMP. An electrode slurry, a battery electrode, and a battery were obtained.

  When the binding property of the obtained battery electrode was evaluated, partial peeling of the active material layer was observed, and the binding property was inferior.

  Furthermore, a charge / discharge cycle test of the obtained battery was performed. The results are also shown in Table 4. The obtained battery exhibited good capacity maintenance ratios, and thus showed good repeated charge / discharge cycle characteristics.

  According to the present invention, a battery having excellent charge / discharge characteristics during repeated charge / discharge can be obtained.

1: Negative electrode lead 2: Lid (conductive)
3: Teflon (registered trademark) (registered trademark) seal 4: Mesh for current collection 5: Negative electrode (metal lithium foil)
6: Glass filter 7: Separator 8: Positive electrode 9: Container (conductive)
10: Positive lead wire

Claims (5)

For a battery containing a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm, an active material, and a current collector A battery comprising an electrode and an electrolytic solution. A battery electrode comprising a latex and an active material containing a vinyl chloride polymer having an average particle diameter of 0.05 to 1.0 μm and / or a vinyl chloride copolymer having an average particle diameter of 0.05 to 1.0 μm. The battery according to claim 1, which is a battery electrode obtained by applying and drying the battery electrode slurry contained on the current collector. The vinyl chloride copolymer includes a structural unit represented by the following general formula (1) and / or general formula (2) derived from a fatty acid vinyl and / or a (meth) acrylic acid ester. Alternatively, the battery according to claim 2.

(In the formula, R ₁ represents an alkyl group having 1 to 17 carbon atoms.)

(In the formula, R ₂ represents an alkyl group having 1 to 18 carbon atoms, and R ₃ represents hydrogen or a methyl group.) The battery according to claim 1, wherein the battery is a secondary battery. The battery according to claim 4, wherein the secondary battery is a lithium ion secondary battery.

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