JP2014017250A - Nonaqueous electrolyte secondary battery and method for using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery in which gas generation during preserved at high temperature is suppressed.SOLUTION: A nonaqueous electrolyte secondary battery comprises: a nonaqueous electrolyte which contains a lithium salt and a nonaqueous solvent dissolving the lithium salt; and a negative electrode and a positive electrode which are capable of absorbing and desorbing lithium ions. The negative electrode includes a negative electrode active material absorbing and desorbing lithium ions at a noble potential higher than 1.0 V (vs.Li/Li), the nonaqueous solvent includes 30 vol.% or less of ethylene carbonate relative to the nonaqueous solvent, and the nonaqueous electrolyte further includes a compound having an isocyanate group.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery including a non-aqueous electrolyte, and further relates to a method of using the non-aqueous electrolyte secondary battery.

  Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are practically used as a wide range of power sources ranging from power sources for so-called portable electronic devices such as mobile phones and laptop computers to in-vehicle power sources for driving automobiles and large power sources for stationary applications. It is becoming. However, with the recent high performance of electronic devices and the application to in-vehicle power supplies for driving and large power supplies for stationary applications, the demand for applied secondary batteries is increasing, and the high performance of the battery characteristics of secondary batteries is increasing. For example, it is required to achieve high levels of improvement in capacity, high temperature storage characteristics, cycle characteristics, and the like.

As a negative electrode used for a non-aqueous electrolyte secondary battery, graphite or the like is widely used. However, in recent years, lithium has a higher potential (about 1.55 V (vs. Li / Li ⁺ )) than graphite. Lithium-titanium composite oxides that absorb and release are attracting attention. Lithium-titanium composite oxide, in principle, does not precipitate lithium during charging, and does not expand or contract the crystal lattice that accompanies charging / discharging, so it has excellent high-rate cycle characteristics and excellent safety. (Patent Document 1).

  On the other hand, the non-aqueous electrolyte used for the non-aqueous electrolyte secondary battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

  However, a non-aqueous electrolyte secondary battery using a lithium titanium composite oxide generates more gas than a non-aqueous electrolyte secondary battery using graphite or the like during long-term high-temperature storage. This gas generation is thought to be mainly due to the reaction between the non-aqueous electrolyte and the negative electrode, but various proposals have been made to suppress the gas generation (Patent Documents 2 and 3). For example, Patent Document 3 discusses the reduction of swelling by adding an acid anhydride to a nonaqueous electrolytic solution.

  Patent Document 4 describes that the use of an organic compound having an isocyanato group can greatly suppress the generation of these gases.

Japanese Laid-Open Patent Publication No. 2005-142047 Japanese Unexamined Patent Publication No. 2008-91327 Japanese Unexamined Patent Publication No. 2012-4121 Japanese Unexamined Patent Publication No. 2009-54319

However, as described above, various efforts have been made to improve the suppression of gas generation. However, it is not yet sufficient to achieve sufficient battery characteristics, and further improvements are required.
The present invention suppresses gas generation during high-temperature storage and has favorable battery characteristics in a non-aqueous electrolyte secondary battery including a negative electrode active material that absorbs and releases lithium at a noble potential more than graphite. An object is to provide a non-aqueous electrolyte secondary battery.

As a result of intensive studies to solve the above-mentioned problems, the inventors have made a non-aqueous electrolyte containing a negative electrode active material that occludes and releases lithium ions at a potential nobler than 1.0 V (vs. Li ^/ Li ⁺ ). In secondary batteries, it was found that a non-aqueous electrolyte secondary battery with improved gas generation can be realized by including a specific compound in the non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery. The present invention has been completed.

That is, the gist of the present invention is as follows.
(1) A non-aqueous electrolyte solution including a lithium salt and a non-aqueous solvent that dissolves the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte secondary battery including a positive electrode,
The negative electrode includes a negative electrode active material that occludes and releases lithium ions at a potential nobler than 1.0 V (vs. Li ^/ Li ⁺ );
The non-aqueous electrolyte secondary battery, wherein the non-aqueous solvent contains 30% by volume or less of ethylene carbonate with respect to the non-aqueous solvent, and the non-aqueous electrolyte further contains a compound having an isocyanate group.
(2) The non-aqueous electrolyte secondary battery according to (1), wherein the compound having an isocyanate group is a compound represented by the following general formula (1).

(Wherein, A represents a hydrogen atom, a halogen atom, a vinyl group, an isocyanate group, or a _C 1 ~
C represents a _{2 0} aliphatic hydrocarbon group (which may have a hetero atom) or a C ₆ -C _{2 0} aromatic hydrocarbon group (which may have a hetero atom). B is CO 2, S 2 O
₂ or C ₁ -C ₂₀ aliphatic hydrocarbon group (may have a hetero atom)
Or a C ₆ -C ₂₀ aromatic hydrocarbon group (which may have a hetero atom). )
(3) The non-aqueous electrolyte secondary battery according to (2) above, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the above general formula (2), X represents a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with fluorine)
(4) The content of the isocyanate group-containing compound is 0.01% by mass or more and 10% by mass or less with respect to the entire non-aqueous electrolyte solution, and any one of the above (1) to (3) The non-aqueous electrolyte secondary battery according to item.
(5) The non-aqueous electrolyte secondary battery according to any one of (1) to (4), wherein the negative electrode active material is a lithium titanium composite oxide.

According to the present invention, in a non-aqueous electrolyte secondary battery using a negative electrode active material that occludes and releases lithium ions at a potential nobler than 1.0 V (vs. Li ^/ Li ⁺ ), the non-aqueous solvent contains ethylene carbonate. A non-aqueous electrolyte secondary battery with improved gas generation can be provided by containing 30% by volume or less with respect to the non-aqueous solvent and the non-aqueous electrolyte further contains a compound having an isocyanate group.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.
Here, “weight%”, “weight ppm”, and “part by weight” are synonymous with “mass%”, “mass ppm”, and “part by weight”, respectively. In addition, when “ppm” is simply described, it indicates “weight ppm”.

  The non-aqueous electrolyte secondary battery of the present invention is suitable for use as, for example, a lithium secondary battery. The non-aqueous electrolyte secondary battery of the present invention can take a known structure, and typically includes a negative electrode and a positive electrode that can occlude and release ions (for example, lithium ions), a non-aqueous electrolyte, and a separator. Is provided.

[I. Non-aqueous electrolyte]
The non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery of the present invention relates to a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent for dissolving the lithium salt, and the non-aqueous solvent contains ethylene carbonate. The non-aqueous solvent contains 30% by volume or less, and the non-aqueous electrolyte further contains a compound having an isocyanate group.

[1. Ethylene carbonate]
The production method of ethylene carbonate used in the present invention is not particularly limited, and any known method can be selected and produced.
The ethylene carbonate of the present invention is usually 10% by volume or more, preferably 15% by volume or more, more preferably 20% by volume or more, and 30% by volume or less, preferably 28% by volume or less, in 100% by volume of the nonaqueous solvent. More preferably, it is used in the range of 25% by volume or less. If it is this range, the gas generation | occurrence | production suppression effect will be easy to be acquired and durability improvement effects, such as cycling characteristics and a storage characteristic, will be easy to be acquired.
Although details are not yet detailed and not limited, it is considered that gas generation is mainly caused by reductive decomposition of the electrolytic solution on the negative electrode surface. Among them, ethylene carbonate is easily subjected to reductive decomposition and is a main factor of gas generation. When the content of ethylene carbonate is in the above range, decomposition of ethylene carbonate is suppressed, and gas generation during high-temperature storage is reduced.

[2. Compound having an isocyanate group]
The compound having an isocyanate group used in the present invention is not particularly limited as long as it is a compound having an isocyanate group in the molecule represented by the general formula (1), preferably the general formula (2). .

(In the above general formula (2), A represents a hydrogen atom, a halogen atom, a vinyl group, an isocyanate group, or a C ₁ to C ₂₀ aliphatic hydrocarbon group (which may have a hetero atom) or C.
₆ -C represents a _{2 0} aromatic hydrocarbon group (which may have a hetero atom). B is
CO 2, S ₂ O ₂ , C ₁ to C ₂₀ aliphatic hydrocarbon group (which may have a hetero atom), or C _{6 to} C ₂₀ aromatic hydrocarbon group (having a hetero atom) May be). )

(In the above general formula (2), X represents a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with fluorine)
Specific examples of the compound represented by the general formula (1) include, for example, methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, isopropyl isocyanate, n-butyl isocyanate, t-butyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, and cyclohexyl isocyanate. Monoisocyanates such as phenyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, vinyl isocyanate, allyl isocyanate;
Etc.

  In the said General formula (2), X is a C1-C16 hydrocarbon group which may be substituted by the fluorine. The carbon number of X is preferably 2 or more, more preferably 3 or more, particularly preferably 4 or more, and is preferably 14 or less, more preferably 12 or less, particularly preferably 10 or less, and most preferably 8 or less. The type of X is not particularly limited as long as it is a hydrocarbon group. Any of an aliphatic chain alkylene group, an aliphatic cyclic alkylene group and an aromatic ring-containing hydrocarbon group may be used, but an aliphatic chain alkylene group or an aliphatic cyclic alkylene group is preferred.

Specific examples of the compound represented by the general formula (2) include, for example,
Linear polymethylene diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate; 1 -Methylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, 3-methylhexamethylene diisocyanate, 1,1-dimethylhexamethylene diisocyanate, 1,2-dimethylhexamethylene diisocyanate, 1,3-dimethylhexamethylene diisocyanate, 1,4 -Dimethylhexamethylene diisocyanate Branched alkylene diisocyanates such as 1,5-dimethylhexamethylene diisocyanate, 1,6-dimethylhexamethylene diisocyanate, 12,3-trimethylhexamethylene diisocyanate; 1,4-diisocyanato-2-butene, 1,5 -Diisocyanato-2-pentene, 1,5-diisocyanato-3-pentene, 1,6-diisocyanato-2-hexene, 1,6-diisocyanato-3-hexene, 1,8-diisocyanato-2-octene, 1,8 Diisocyanatoalkenes such as diisocyanato-3-octene and 1,8-diisocyanato-4-octene; 1,3-diisocyanato-2-fluoropropane, 1,3-diisocyanato-2,2-difluoropropane, 1 , 4-Diisocyanato-2-fluorobutane 1,4-diisocyanato-2,2-difluorobutane, 1,4-diisocyanato-2,3-difluorobutane, 1,6-diisocyanato-2-fluorohexane, 1,6-diisocyanato-3-fluorohexane, 1, 6-diisocyanato-2,2-difluorohexane, 1,6-diisocyanato-2,3-difluorohexane, 1,6-diisocyanato-2,4-difluorohexane, 1,6-diisocyanato-2,5-difluorohexane, 1,6-diisocyanato-3,3-difluorohexane, 1,6-diisocyanato-3,4-difluorohexane,
1,8-diisocyanato-2-fluorooctane, 1,8-diisocyanato-3-fluorooctane, 1,8-diisocyanato-4-fluorooctane, 1,8-diisocyanato-2,2-difluorooctane, 1,8- Diisocyanato-2,3-difluorooctane, 1,8-diisocyanato-2,4-difluorooctane, 1,8-diisocyanato-2,5-difluorooctane, 1,8-diisocyanato-2,6-difluorooctane, 1, Fluorine-substituted diisocyanatoalkanes such as 8-diisocyanato-2,7-difluorooctane; 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanato Rhohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane Cycloalkane ring-containing diisocyanates such as -2,4'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate; 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate 1,4-phenylene diisocyanate, tolylene-2,3-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,5-diisocyanate, tolylene-2,6-diisocyanate Tolylene-3,4-diisocyanate, tolylene-3,5-diisocyanate, 1,2-bis (isocyanatomethyl) benzene, 1,3-bis (isocyanatomethyl) benzene, 1,4-bis (isocyanatomethyl) Benzene, 2,4-diisocyanatobiphenyl, 2,6-diisocyanatobiphenyl, 2,2'-diisocyanatobiphenyl, 3,3'-diisocyanatobiphenyl, 4,4'-diisocyanato-2-methyl Biphenyl, 4,4'-diisocyanato-3-methylbiphenyl, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, 4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanato-2-methyldiphenylmethane 4,4'-diisocyanato-3-methyldiphenylmethane, 4,4'-diisocyanate Nato-3,3'-dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, 1,8-diisocyanatonaphthalene, 2,3-diisocyanatonaphthalene, 1,5-bis (isocyanatomethyl) naphthalene, 1, , 8-bis (isocyanatomethyl) naphthalene, aromatic ring-containing diisocyanates such as 2,3-bis (isocyanatomethyl) naphthalene;
Etc.

Among these,
Linear polymethylene diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate; 1 -Methylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, 3-methylhexamethylene diisocyanate, 1,1-dimethylhexamethylene diisocyanate, 1,2-dimethylhexamethylene diisocyanate, 1,3-dimethylhexamethylene diisocyanate, 1,4 -Dimethylhexamethylene diisocyanate Branched alkylene diisocyanates such as 1,5-dimethylhexamethylene diisocyanate, 1,6-dimethylhexamethylene diisocyanate, 12,3-trimethylhexamethylene diisocyanate; 1,2-diisocyanatocyclopentane, 1,3- Diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (Isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane-3,3 - diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, cycloalkane ring containing diisocyanates and the like;
Is preferred.

Moreover,
Linear polymethylene diisocyanates selected from tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate; 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane 4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylme Down-3,3'-diisocyanate, cycloalkane ring containing diisocyanates selected from dicyclohexylmethane-4,4'-diisocyanate;
Is particularly preferred.

The production method of the compound having an isocyanate group is not particularly limited, and can be produced by arbitrarily selecting a known method.
Moreover, the isocyanate group in this invention mentioned above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
In the non-aqueous electrolyte of the present invention, the content of the compound containing an isocyanate group is usually 0.01% by mass or more, preferably 0.1% by mass or more, based on the total mass of the non-aqueous electrolyte. Preferably it is 0.5 mass% or more, More preferably, it is 1 mass% or more, and it is 10 mass% or less normally, Preferably it is 8 mass% or less, More preferably, it is 5 mass% or less. When the content is within the above range, durability such as cycle and storage, and suppression of gas generation amount are realized, the effect of the present invention can be sufficiently exerted, and resistance is prevented from increasing. It is easy to avoid a decrease in output.

A non-aqueous electrolyte secondary battery using a lithium-titanium composite oxide generates more gas than a non-aqueous electrolyte secondary battery using graphite or the like during long-term high-temperature storage. As for the cause of gas generation, the details are not yet clear, but it is assumed as follows.
Metal oxides such as lithium-titanium composite oxides contain a lot of chemically adsorbed water or surface OH groups, and these chemically adsorbed water or surface OH groups react with the non-aqueous electrolyte solution to generate decomposition gas.

  Here, when the compound which has an isocyanate group is added, since the compound which has an isocyanate group reacts with OH group of the metal oxide surface, it is guessed that said decomposition gas generation | occurrence | production is suppressed. On the other hand, chemically adsorbed water reacts with LiPF6 to generate hydrogen fluoride, which causes gas generation. The compound having an isocyanate group also reacts with water liberated in the electrolytic solution, and has an effect of suppressing generation of hydrogen fluoride and suppressing gas generation.

  Furthermore, in the present invention, it is important that the ethylene carbonate content is 30% by mass or less. By setting the content of ethylene carbonate to 30% by mass or less, decomposition of ethylene carbonate, which is a cause of gas generation, is suppressed, and gas generation during high-temperature storage is reduced.

[3. solvent]
As the non-aqueous solvent, in addition to the above-mentioned diethyl carbonate, saturated cyclic carbonates other than ethylene carbonate, cyclic sulfone compounds, cyclic carbonates having fluorine atoms,
Symmetrical chain carbonates, asymmetrical chain carbonates, cyclic or chain carboxylic acid esters, ether compounds, and the like can be used. Moreover, it is preferable to contain at least one among a saturated cyclic carbonate and a cyclic sulfone compound.

[Saturated cyclic carbonates other than ethylene carbonate]
Examples of saturated cyclic carbonates other than ethylene carbonate include those having an alkylene group having 3 to 4 carbon atoms.
Specific examples of the saturated cyclic carbonate having 3 to 4 carbon atoms include propylene carbonate and butylene carbonate, and propylene carbonate is preferable.

Saturated cyclic carbonates other than ethylene carbonate may be used alone or in combination of two or more in any combination and ratio.
The content when using a saturated cyclic carbonate other than ethylene carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. However, the lower limit of the content when used alone is non- It is 5 volume% or more in 100 volume% of aqueous solvents, More preferably, it is 10 volume% or more. By setting this range, the decrease in electrical conductivity resulting from the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the large current discharge characteristics, negative electrode stability, and cycle characteristics of the non-aqueous electrolyte secondary battery are good. It becomes easy to be in a range. Moreover, an upper limit is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in ionic conductivity is suppressed, and as a result, the load characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

  Moreover, one of the preferable combinations when using 2 or more types of saturated cyclic carbonates other than ethylene carbonate in arbitrary combinations is a combination of butylene carbonate and propylene carbonate. In this case, the volume ratio of butylene carbonate to propylene carbonate is preferably 1:99 to 60:40, particularly preferably 5:95 to 50:50.

[3.2 Cyclic sulfone compound]
The cyclic sulfone compound is not particularly limited as long as the cyclic moiety is constituted by a methylene group and a sulfonyl group (—S (═O) ₂ —), and any cyclic sulfone compound can be used. The cyclic sulfone compound may optionally have a substituent. Among them, the cyclic moiety is preferably composed of 3 or more methylene groups and 1 or more sulfonyl groups, optionally having a substituent, and having a molecular weight of 500 or less.

The methylene group at the cyclic site in the cyclic sulfone compound is preferably 3-6, and the sulfonyl group is preferably 1-2.
Examples of the substituent include a halogen atom, an alkyl group, and an alkyl group substituted with a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom is mentioned, Preferably it is a fluorine atom or a chlorine atom, and a fluorine atom is especially preferable. As an alkyl group, a C1-C4 alkyl group is mentioned, 1-2 are preferable. Examples of the alkyl group substituted with a halogen atom include an alkyl group having 1 to 4 carbon atoms substituted with a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and an alkyl group having 1 to 2 carbon atoms. Is preferred. The number of substituents may be one or plural, and preferably 1 to 3 from the viewpoint of the effect of the present invention.

Examples of cyclic sulfone compounds include trimethylene sulfones, tetramethylene sulfones, hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, hexamethylene disulfones that are disulfone compounds, Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

  As the cyclic sulfone compound, sulfolane and / or sulfolane derivatives (hereinafter sometimes abbreviated as “sulfolanes” including sulfolane) are preferable in that the effects of the present invention can be easily obtained. As the sulfolane derivative, a sulfolane derivative in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with a halogen atom is particularly preferable. Moreover, as a sulfolane derivative, what has an alkyl group can also be used, and the hydrogen atom couple | bonded with the carbon atom which comprises an alkyl group may be substituted by the halogen atom.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom or a chlorine atom is preferable, and a fluorine atom is particularly preferable. When this is a substituent on a carbon atom constituting a sulfolane ring, it is a substituent of an alkyl group bonded to the sulfolane ring. Applies to both.

  Examples of the sulfolane derivative containing an alkyl group as a substituent of the sulfolane ring include 2-methylsulfolane, 3-methylsulfolane, 2,2-dimethylsulfolane, 3,3-dimethylsulfolane, 2,3-dimethylsulfolane, 2,4 -Dimethylsulfolane, 2,5-dimethylsulfolane, 2,2,3-trimethylsulfolane, 2,2,4-trimethylsulfolane, 2,2,5-trimethylsulfolane, 2,3,3-trimethylsulfolane, 3,3 , 4-Trimethylsulfolane, 3,3,5-trimethylsulfolane, 2,3,4-trimethylsulfolane, 2,3,5-trimethylsulfolane, 2,2,3,3-tetramethylsulfolane, 2,2,3 , 4-tetramethylsulfolane, 2,2,3,5-tetramethylsulfolane, 2,2,4,4-the Lamethyl sulfolane, 2,2,4,5-tetramethyl sulfolane, 2,2,5,5-tetramethyl sulfolane, 2,3,3,4-tetramethyl sulfolane, 2,3,3,5-tetramethyl Sulfolane, 2,3,4,4-tetramethylsulfolane, 2,3,4,5-tetramethylsulfolane, 3,3,4,4-tetramethylsulfolane, 2,2,3,4,4-pentamethyl Sulfolane, 2,2,3,3,5-pentamethylsulfolane, 2,2,3,4,4-pentamethylsulfolane, 2,2,3,4,5-pentamethylsulfolane, 2,3,3 4,4-pentamethylsulfolane, 2,3,3,4,5-pentamethylsulfolane, 2,2,3,3,4,4-hexamethylsulfolane, 2,2,3,3,4,5- Hexamethylsulfolane, 2, , 3,3,5,5-hexamethylsulfolane, 2,2,3,4,5,5-hexamethylsulfolane, 2,2,3,3,4,4,5-heptamethylsulfolane, 2,2 , 3,3,4,5,5-heptamethylsulfolane, octamethylsulfolane and the like.

Examples of the sulfolane derivative containing a fluorine atom as a substituent of the sulfolane ring include 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2, 5-difluorosulfolane, 3,4-difluorosulfolane, 2,2,3-trifluorosulfolane, 2,3,3-trifluorosulfolane, 2,2,4-trifluorosulfolane, 2,2,5-trifluoro Sulfolane, 2,3,4-trifluorosulfolane, 2,3,5-trifluorosulfolane, 2,4,4-trifluorosulfolane, 2,2,3,3-tetrafluorosulfolane, 2,2,3, 4-tetrafluorosulfolane, 2,2,4,4-tetrafluorosulfolane, 2,2,5,5- Trifluorosulfolane, 2,3,3,4-tetrafluorosulfolane, 2,3,3,5-tetrafluorosulfolane, 2,3,4,4-tetrafluorosulfolane, 2,3,4,5-tetrafluoro Sulfolane, 2,2,3,3,4-pentafluorosulfolane, 2,2,3,3,5-pentafluorosulfolane, 2,2
, 3,4,4-pentafluorosulfolane, 2,2,3,4,5-pentafluorosulfolane, 2,3,3,4,4-pentafluorosulfolane, 2,3,3,4,5-penta Fluorosulfolane, 2,2,3,3,4,4-hexafluorosulfolane, 2,2,3,3,4,5-hexafluorosulfolane, 2,2,3,3,5,5-hexafluorosulfolane 2,2,3,4,5,5-hexafluorosulfolane, 2,2,3,3,4,4,5-heptafluorosulfolane, 2,2,3,3,4,5,5-hepta Examples thereof include fluorosulfolane and octafluorosulfolane.

  As a sulfolane derivative having an alkyl group and a fluorine atom as a substituent of the sulfolane ring, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro 2-methylsulfolane, 4-fluoro-3-methylsulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoro-2,4- Dimethylsulfolane, 4-fluoro-2,4-dimethylsulfolane, 5-fluoro-2,4-dimethylsulfolane, 2,2-difluoro-3-methylsulfolane, 2,3-difluoro-3-methylsulfolane, 2,4 -Difluoro-3-methylsulfolane, 2,5-difluoro-3-methylsulfolane 3,4-difluoro-3-methylsulfolane, 3,5-difluoro-3-methylsulfolane, 4,4-difluoro-3-methylsulfolane, 4,5-difluoro-3-methylsulfolane, 5,5-difluoro- 3-methylsulfolane, 2,2,3-trifluoro-3-methylsulfolane, 2,2,4-trifluoro-3-methylsulfolane, 2,2,5-trifluoro-3-methylsulfolane, 2,3 , 4-trifluoro-3-methylsulfolane, 2,3,5-trifluoro-3-methylsulfolane, 2,4,4-trifluoro-3-methylsulfolane, 2,4,5-trifluoro-3- Methyl sulfolane, 2,5,5-trifluoro-3-methyl sulfolane, 3,4,4-trifluoro-3-methyl sulfolane, 3,4,5-trifluoro -3-methyl sulfolane, 4,4,5-trifluoro-3-methyl sulfolane, 4,5,5-trifluoro-3-methyl sulfolane, 2,2,3,4-tetrafluoro-3-methyl sulfolane, 2,2,3,5-tetrafluoro-3-methylsulfolane, 2,2,4,4-tetrafluoro-3-methylsulfolane, 2,2,4,5-tetrafluoro-3-methylsulfolane, 2, 2,5,5-tetrafluoro-3-methylsulfolane, 2,3,4,4-tetrafluoro-3-methylsulfolane, 2,3,4,5-tetrafluoro-3-methylsulfolane, 2,3, 5,5-tetrafluoro-3-methylsulfolane, 3,4,4,5-tetrafluoro-3-methylsulfolane, 3,4,5,5-tetrafluoro-3-methylsulfolane, 4,4 , 5,5-tetrafluoro-3-methylsulfolane, 2,2,3,4,4-pentafluoro-3-methylsulfolane, 2,2,3,4,5-pentafluoro-3-methylsulfolane, 2, , 2,3,5,5-pentafluoro-3-methylsulfolane, 2,3,4,4,5-pentafluoro-3-methylsulfolane, 2,3,4,5,5-pentafluoro-3- Methylsulfolane, 2,2,3,4,4,5-hexafluoro-3-methylsulfolane, 2,2,3,4,5,5-hexafluoro-3-methylsulfolane, 2,3,4,4 , 5,5-hexafluoro-3-methylsulfolane, heptafluoro-3-methylsulfolane, and the like.

As a sulfolane derivative having a monofluoroalkyl group and a fluorine atom as a substituent of the sulfolane ring, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-fluoro-3- (fluoromethyl) sulfolane, 3-fluoro- 3- (fluoromethyl) sulfolane, 4-fluoro-3- (fluoromethyl) sulfolane, 5-fluoro-3- (fluoromethyl) sulfolane, 2,2-difluoro-3- (fluoromethyl) sulfolane, 2,3- Difluoro-3- (fluoromethyl) sulfolane, 2,4-difluoro-3- (fluoromethyl) sulfolane, 2,5-difluoro-3- (fluoromethyl) sulfolane, 3,4-difluoro-3- (fluoromethyl) Sulfolane, 3,5-difluoro-3- (fluoromethyl) sulfur Lan, 4,4-difluoro-3- (fluoromethyl) sulfolane, 4,5-difluoro-3- (fluoromethyl) sulfolane, 5,5-difluoro-3- (fluoromethyl) sulfolane, 2,2,3- Trifluoro-3- (fluoromethyl) sulfolane, 2,2,4-trifluoro-3- (fluoromethyl) sulfolane, 2,2,5-trifluoro-3- (fluoromethyl) sulfolane, 2,3,4 -Trifluoro-3- (fluoromethyl) sulfolane, 2,3,5-trifluoro-3- (fluoromethyl) sulfolane, 2,4,4-trifluoro-3- (fluoromethyl) sulfolane, 2,4, 5-trifluoro-3- (fluoromethyl) sulfolane, 2,5,5-trifluoro-3- (fluoromethyl) sulfolane, 3,4,4-tri Fluoro-3- (fluoromethyl) sulfolane, 3,4,5-trifluoro-3- (fluoromethyl) sulfolane, 4,4,5-trifluoro-3- (fluoromethyl) sulfolane, 4,5,5- Trifluoro-3- (fluoromethyl) sulfolane, 2,2,3,4-tetrafluoro-3- (fluoromethyl) sulfolane, 2,2,3,5-tetrafluoro-3- (fluoromethyl) sulfolane, 2 , 2,4,4-Tetrafluoro-3- (fluoromethyl) sulfolane, 2,2,4,5-tetrafluoro-3- (fluoromethyl) sulfolane, 2,2,5,5-tetrafluoro-3- (Fluoromethyl) sulfolane, 2,3,4,4-tetrafluoro-3- (fluoromethyl) sulfolane, 2,3,4,5-tetrafluoro-3- (fluorome Til) sulfolane, 2,3,5,5-tetrafluoro-3- (fluoromethyl) sulfolane, 3,4,4,5-tetrafluoro-3- (fluoromethyl) sulfolane, 3,4,5,5- Tetrafluoro-3- (fluoromethyl) sulfolane, 4,4,5,5-tetrafluoro-3- (fluoromethyl) sulfolane, 2,2,3,4,4-pentafluoro-3- (fluoromethyl) sulfolane 2,2,3,4,5-pentafluoro-3- (fluoromethyl) sulfolane, 2,2,3,5,5-pentafluoro-3- (fluoromethyl) sulfolane, 2,3,4,4 , 5-pentafluoro-3- (fluoromethyl) sulfolane, 2,3,4,5,5-pentafluoro-3- (fluoromethyl) sulfolane, 2,2,3,4,4,5-hexafur Rho-3- (fluoromethyl) sulfolane, 2,2,3,4,5,5-hexafluoro-3- (fluoromethyl) sulfolane, 2,3,4,4,5,5-hexafluoro-3- (Fluoromethyl) sulfolane, heptafluoro-3- (fluoromethyl) sulfolane and the like can be mentioned.

Examples of the sulfolane derivative having a difluoroalkyl substituent and a fluorine atom as a sulfolane ring substituent include 2-difluoromethylsulfolane, 3-difluoromethylsulfolane, 2-fluoro-3- (difluoromethyl) sulfolane, 3-fluoro- 3- (difluoromethyl) sulfolane, 4-fluoro-3- (difluoromethyl) sulfolane, 5-fluoro-3- (difluoromethyl) sulfolane, 2,2-difluoro-3- (difluoromethyl) sulfolane, 2,3- Difluoro-3- (difluoromethyl) sulfolane, 2,4-difluoro-3- (difluoromethyl) sulfolane, 2,5-difluoro-3- (difluoromethyl) sulfolane, 3,4-difluoro-3- (difluoromethyl) Sulfolane, 3,5-difluoro-3 (Difluoromethyl) sulfolane, 4,4-difluoro-3- (difluoromethyl) sulfolane, 4,5-difluoro-3- (difluoromethyl) sulfolane, 5,5-difluoro-3- (difluoromethyl) sulfolane, 2, 2,3-trifluoro-3- (difluoromethyl) sulfolane, 2,2,4-trifluoro-3- (difluoromethyl) sulfolane, 2,2,5-trifluoro-3- (difluoromethyl) sulfolane, 2, , 3,4-trifluoro-3- (difluoromethyl) sulfolane, 2,3,5-trifluoro-3- (difluoromethyl) sulfolane, 2,4,4-trifluoro-3- (difluoromethyl) sulfolane, 2,4,5-trifluoro-3- (difluoromethyl) sulfolane, 2,5,5-trifluoro-3- Difluoromethyl) sulfolane, 3,4,4-trifluoro-3- (difluoromethyl) sulfolane, 3,4,5-trifluoro-3- (difluoromethyl) sulfolane, 4,4,5-trifluoro-3- (Difluoromethyl) sulfolane, 4,5,5-trifluoro-3- (difluoromethyl) sulfolane, 2,2,3,4-tetrafluoro-3- (difluoromethyl) sulfolane, 2,2,3,5- Tetrafluoro-3- (difluoromethyl) sulfolane, 2,2,4,4-tetrafluoro-3- (difluoromethyl) sulfolane, 2,2,4,5-tetrafluoro-3- (difluoromethyl) sulfolane, 2, , 2,5,5-tetrafluoro-3- (difluoromethyl) sulfolane, 2,3,4,4-tetrafluoro-3- (difluoro Methyl) sulfolane, 2,3,4,5-tetrafluoro-3- (difluoromethyl) sulfolane, 2,3,5,5-tetrafluoro-3- (difluoromethyl) sulfolane, 3,4,4,5- Tetrafluoro-3- (difluoromethyl) sulfolane, 3,4,5,5-tetrafluoro-3- (difluoromethyl) sulfolane, 4,4,5,5-tetrafluoro-3- (difluoromethyl) sulfolane, 2, , 2,3,4,4-pentafluoro-3- (difluoromethyl) sulfolane, 2,2,3,4,5-pentafluoro-3- (difluoromethyl) sulfolane, 2,2,3,5,5 -Pentafluoro-3- (difluoromethyl) sulfolane, 2,3,4,4,5-pentafluoro-3- (difluoromethyl) sulfolane, 2,3,4,5,5 Pentafluoro-3- (difluoromethyl) sulfolane, 2,2,3,4,4,5-hexafluoro-3- (difluoromethyl) sulfolane, 2,2,3,4,5,5-hexafluoro-3 -(Difluoromethyl) sulfolane, 2,3,4,4,5,5-hexafluoro-3- (difluoromethyl) sulfolane, heptafluoro-3- (difluoromethyl) sulfolane and the like.

As a sulfolane ring substituent, a sulfolane derivative having a trifluoroalkyl substituent and a fluorine atom includes 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane, 5-fluoro-3- (trifluoromethyl) sulfolane, 2,2-difluoro-3- (trifluoro) Methyl) sulfolane, 2,3-difluoro-3- (trifluoromethyl) sulfolane, 2,4-difluoro-3- (trifluoromethyl) sulfolane, 2,5-difluoro-3- (trifluoromethyl) sulfolane, 3, , 4-Difluoro-3- (trifluoromethyl) sulfolane 3,5-difluoro-3- (trifluoromethyl) sulfolane, 4,4-difluoro-3- (trifluoromethyl) sulfolane, 4,5-difluoro-3- (trifluoromethyl) sulfolane, 5,5-difluoro -3- (trifluoromethyl) sulfolane, 2,2,3-trifluoro-3- (trifluoromethyl) sulfolane, 2,2,4-trifluoro-3- (trifluoromethyl) sulfolane, 2,2, 5-trifluoro-3- (trifluoromethyl) sulfolane, 2,3,4-trifluoro-3- (trifluoromethyl) sulfolane, 2,3,5-trifluoro-3- (trifluoromethyl) sulfolane, 2,4,4-trifluoro-3- (trifluoromethyl) sulfolane, 2,4,5-trifluoro-3- (trifluoromethyl) ) Sulfolane, 2,5,5-trifluoro-3- (trifluoromethyl) sulfolane, 3,4,4-trifluoro-3- (trifluoromethyl) sulfolane, 3,4,5-trifluoro-3- (Trifluoromethyl) sulfolane, 4,4,5-trifluoro-3- (trifluoromethyl) sulfolane, 4,5,5-trifluoro-3- (trifluoromethyl) sulfolane, 2,2,3,4 -Tetrafluoro-3- (trifluoromethyl) sulfolane, 2,2,3,5-tetrafluoro-3- (trifluoromethyl) sulfolane, 2,2,4,4-tetrafluoro-3- (trifluoromethyl) ) Sulfolane, 2,2,4,5-tetrafluoro-3- (trifluoromethyl) sulfolane, 2,2,5,5-tetrafluoro-3- (trifluorome Til) sulfolane, 2,3,4,4-tetrafluoro-3- (trifluoromethyl) sulfolane, 2,3,4,5-tetrafluoro-3- (trifluoromethyl) sulfolane, 2,3,5, 5-tetrafluoro-3- (trifluoromethyl) sulfolane, 3,4,4,5-tetrafluoro-3- (trifluoromethyl) sulfolane, 3,4,5,5-tetrafluoro-3- (trifluoro) Methyl) sulfolane, 4,4,5,5-tetrafluoro-3- (trifluoromethyl) sulfolane, 2,2,3,4,4-pentafluoro-3-
(Trifluoromethyl) sulfolane, 2,2,3,4,5-pentafluoro-3- (trifluoromethyl) sulfolane, 2,2,3,5,5-pentafluoro-3- (trifluoromethyl) sulfolane 2,3,4,4,5-pentafluoro-3- (trifluoromethyl) sulfolane, 2,3,4,5,5-pentafluoro-3- (trifluoromethyl) sulfolane, 2,2,3 , 4,4,5-hexafluoro-3- (trifluoromethyl) sulfolane, 2,2,3,4,5,5-hexafluoro-3- (trifluoromethyl) sulfolane, 2,3,4,4 , 5,5-hexafluoro-3- (trifluoromethyl) sulfolane, heptafluoro-3- (trifluoromethyl) sulfolane, and the like.

  Among the sulfolanes mentioned above, sulfolane, 2-methylsulfolane, 3-methylsulfolane, 2,2-dimethylsulfolane, 3,3-dimethylsulfolane, 2,3-dimethylsulfolane, 2,4-dimethylsulfolane, 2, 5-dimethylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2-fluoro-3-methylsulfolane, 3-fluoro-3-methylsulfolane, 4-fluoro-3-methylsulfolane, 5-fluoro-3-methylsulfolane 2-fluoro-2-methyl sulfolane, 3-fluoro-2-methyl sulfolane, 4-fluoro-2-methyl sulfolane, 5-fluoro-2-methyl sulfolane, 2-fluoro-2,4-dimethyl sulfolane, 3- Fluoro-2,4-dimethylsulfolane, 4-fluoro-2, -Dimethyl sulfolane, 5-fluoro-2,4-dimethyl sulfolane, 2-fluoromethyl sulfolane, 3-fluoromethyl sulfolane, 2-difluoromethyl sulfolane, 3-difluoromethyl sulfolane, 2-trifluoromethyl sulfolane, 3-trifluoro Methyl sulfolane is more preferred.

  Particularly preferred are sulfolane, 2-methyl sulfolane, 3-methyl sulfolane, 2-fluoro sulfolane, 3-fluoro sulfolane, 2-fluoro-3-methyl sulfolane, 3-fluoro-3-methyl sulfolane, 4-fluoro-3- In methyl sulfolane, 5-fluoro-3-methyl sulfolane, 2-fluoromethyl sulfolane, 3-fluoromethyl sulfolane, 2-difluoromethyl sulfolane, 3-difluoromethyl sulfolane, 2-trifluoromethyl sulfolane, 3-trifluoromethyl sulfolane is there.

The number of substituents on the sulfolane ring is preferably 3 or less from the viewpoint of viscosity and electrical conductivity by using a substituted cyclic sulfone compound. Further, when a fluorinated cyclic sulfone compound is used, the number of fluorine atoms is 8 or less from the viewpoint of chemical stability when used as a non-aqueous electrolyte secondary battery and solubility in other solvents. It is preferable.
One kind of the cyclic sulfone compound may be contained alone in the nonaqueous electrolytic solution of the present invention, or two or more kinds thereof may be used in combination in any combination and ratio.

Moreover, there is no restriction | limiting in particular also in a manufacturing method, It is possible to manufacture by selecting a well-known method arbitrarily.
The content of the cyclic sulfone compound is preferably 0.01% by volume or more and 90% by volume or less in 100% by volume of the non-aqueous solvent. Within this range, it is easy to obtain an effect of suppressing gas generation, an effect of improving durability such as cycle characteristics and storage characteristics, etc., and the viscosity of the non-aqueous electrolyte is set to an appropriate range, and the electric conductivity is reduced. Since the decrease can be avoided, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases when charging / discharging the non-aqueous electrolyte secondary battery at a high current density.

  The sulfone compound is also preferably used in combination with a cyclic carbonate. In this case, the volume ratio of the cyclic carbonate to the sulfone compound is preferably 1:99 to 60:40, and particularly preferably 5:95 to 50:50. When the sulfone compound is contained within this range, the decomposition of the cyclic carbonate is suppressed and the decomposition gas is reduced.

[3.3 Cyclic carbonate having a fluorine atom]
The cyclic carbonate having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated cyclic carbonate”) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.

  Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate substituted with ethylene carbonate or an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms).

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ionic conductivity. It is preferable because it may provide a property and may suitably form an interface protective film.
A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. Moreover, you may mix and use said saturated cyclic carbonate and cyclic sulfone type compound by arbitrary combinations and a ratio.

  The content when using the fluorinated cyclic carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. However, in 100% by volume of the non-aqueous solvent, preferably 0.01% by volume or more, More preferably, it is 0.1 volume% or more, More preferably, it is 0.2 volume% or more, Preferably it is 95 volume% or less, More preferably, it is 90 volume% or less. Within this range, the non-aqueous electrolyte secondary battery tends to exhibit a sufficient cycle characteristic improvement effect, and avoids a decrease in discharge capacity maintenance rate due to a decrease in high-temperature storage characteristics or an increase in the amount of gas generated. Cheap.

  In addition, the cyclic carbonate which has a fluorine atom expresses an effective function not only as a solvent but as an auxiliary agent described below. There is no clear boundary in the content when used as a cyclic carbonate solvent / auxiliary having a fluorine atom, and the content described in the previous paragraph can be followed as it is.

[3.4 Symmetrical chain carbonate]
Examples of the symmetric chain carbonate used in the present invention include those having 3 to 7 carbon atoms and symmetric chain carbonates having a fluorine atom.
In the present invention, the symmetric chain carbonate is a chain carbonate in which two substituents bonded to the carbonate group are the same. Examples of the symmetric chain carbonate having 3 to 7 carbon atoms include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, di-i-propyl carbonate and the like. Among these, dimethyl carbonate and diethyl carbonate are preferable, and diethyl carbonate is more preferable.

  Further, the number of fluorine atoms contained in the symmetric chain carbonates having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated symmetric chain carbonate”) is not particularly limited as long as it is 2 or more, but usually 6 Or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated symmetrical chain carbonate include a fluorinated dimethyl carbonate derivative and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include difluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoromethyl) carbonate, and bis (trifluoromethyl) carbonate.
Examples of the fluorinated diethyl carbonate derivative include bis (2-fluoroethyl) carbonate, bis (2,2-difluoroethyl) carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

One kind of the symmetric chain carbonate may be contained alone in the nonaqueous electrolytic solution of the present invention, or two or more kinds may be used in combination in any combination and ratio.
Moreover, there is no restriction | limiting in particular also in a manufacturing method, It is possible to manufacture by selecting a well-known method arbitrarily.
The content of the symmetric chain carbonate is 100% by volume in the non-aqueous solvent, and its lower limit is usually 5% by volume or more, preferably 10% by volume or more, more preferably 30% by volume or more, and the upper limit is usually 80%. The volume% or less, preferably 70 volume% or less. If it is this range, the gas generation | occurrence | production suppression effect will be easy to be acquired and durability improvement effects, such as cycling characteristics and a storage characteristic, will be easy to be acquired. In addition, since the viscosity of the non-aqueous electrolyte solution can be set within an appropriate range and a decrease in electrical conductivity can be avoided, the charge / discharge capacity is maintained when charging and discharging the non-aqueous electrolyte secondary battery at a high current density. It is easy to avoid situations where the rate drops.
It is also preferable to use two or more kinds of specific symmetric chain carbonates together with an asymmetric carbonate described later.

[3.5 Asymmetric chain carbonate]
As an asymmetric chain carbonate, a C3-C7 thing is preferable.
Specifically, examples of the asymmetric chain carbonate having 3 to 7 carbon atoms include n-propyl-i-propyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, i-butyl methyl carbonate, t -Butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, i-butyl ethyl carbonate, t-butyl ethyl carbonate, etc. are mentioned.

Among these, n-propyl-i-propyl carbonate, ethyl methyl carbonate, and methyl-n-propyl carbonate are preferable, and ethyl methyl carbonate is particularly preferable.
Further, asymmetric chain carbonates having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated asymmetric chain carbonate”) can also be suitably used. The number of fluorine atoms in the fluorinated asymmetric chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated asymmetric chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated asymmetric chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, and the like.
Fluorinated ethyl methyl carbonate derivatives include (2-fluoroethyl) methyl carbonate, ethyl fluoromethyl carbonate, (2,2-difluoroethyl) methyl carbonate, (2-fluoroethyl) fluoromethyl carbonate, ethyl difluoromethyl carbonate, ( 2,2,2-trifluoroethyl) methyl carbonate, (2,2-difluoroethyl) fluoromethyl carbonate, (2-fluoroethyl) difluoromethyl carbonate, ethyl trifluoromethyl carbonate and the like.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, ethyl- (2,2,2-trifluoroethyl) carbonate, 2,2-difluoro. Examples include ethyl-2′-fluoroethyl carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2,2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, and the like.

As the asymmetric chain carbonate, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.
The content of the asymmetric chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily set to a favorable range. Become. The asymmetric chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the non-aqueous solvent. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte and to make the large current discharge characteristics of the non-aqueous electrolyte secondary battery in a favorable range. .

  It may be preferable to use two or more kinds of specific asymmetric chain carbonates and specific symmetrical carbonates in combination. For example, when ethyl methyl carbonate is used in combination with a specific asymmetric linear carbonate and diethyl carbonate is used in combination with a specific symmetrical linear carbonate, the content of the cyclic carbonate and / or the cyclic sulfone compound is 10% by volume or more and 30 volumes. % Or less, a content of diethyl carbonate of 10% by volume or more and 70% by volume or less, and a content of ethyl methyl carbonate of 10% by volume or more and 80% by volume or less are particularly preferable. By selecting such a content, the viscosity of the non-aqueous electrolyte solution can be reduced while reducing the low-temperature deposition temperature of the electrolyte to improve the ionic conductivity, and a high output can be obtained even at a low temperature.

[3.6 Cyclic or linear carboxylic acid ester]
Examples of the cyclic carboxylic acid ester include those having 3 to 12 total carbon atoms in the structural formula.
Specific examples include γ-butyrolactone, γ-valerolactone, γ-caprolactone, ε-caprolactone, and the like. Among these, when the non-aqueous electrolyte secondary battery is a lithium ion secondary battery, γ-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improved degree of lithium ion dissociation.

The content of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this manner, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Further, the content of the cyclic carboxylic acid ester is preferably 50% by volume or less, more preferably 40% by volume or less, in 100% by volume of the non-aqueous solvent. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula.
Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid-n- Examples include propyl and isopropyl isobutyrate.

Among them, methyl acetate, ethyl acetate, acetate-n-propyl, acetate-n-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoint of improvement of ionic conductivity.
The content of the chain carboxylic acid ester is usually 10% by volume or more, more preferably 15% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. The content of the chain carboxylic acid ester is preferably 80% by volume or less, more preferably 70% by volume or less, in 100% by volume of the non-aqueous solvent. By setting the upper limit in this manner, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

[3.7 Ether compound]
As the ether compound, a chain ether having 3 to 10 carbon atoms, in which part of hydrogen may be substituted with fluorine, or a cyclic ether having 3 to 6 carbon atoms is preferable.
Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, bis (2-fluoroethyl) ether, bis (2,2-difluoroethyl) ether, bis (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,2-trifluoro Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-pro ) Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n -Propyl ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) ( 2,2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-tri Fluoroethyl-n-propyl ether, (3-fluoro-n-propyl) (2,2,2-trifluoroethyl) ether, (2,2,2-trifluoroethyl) (3,3,3- (Lifluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2,2-trifluoroethyl) ether, (2,2,3,3,3-pentafluoro -N-propyl) (2,2,2-trifluoroethyl) ether, n-propyl (1,1,2,2-tetrafluoroethyl) ether, (3-fluoro-n-propyl) (1,1, 2,2-tetrafluoroethyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoro) Ethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3,3-pentafluoro-n-propyl) (1,1,2,2-tetrafluoroethyl) ) Ether, di-n- Propyl ether, (3-fluoro-n-propyl) (n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2, 3,3-tetrafluoro-n-propyl) ether, (2,2,3,3,3-pentafluoro-n-propyl) (n-propyl) ether, bis (3-fluoro-n-propyl) ether, (3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) Ether, (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, bis (3,3,3-trifluoro-n-propyl) ether, (2 , 2, , 3-Tetrafluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (2,2,3,3,3-pentafluoro-n-propyl) (3,3,3 -Trifluoro-n-propyl) ether, bis (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2, 3,3,3-pentafluoro-n-propyl) ether, bis (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, ethoxymethoxymethane, ( 2-fluoroethoxy) methoxymethane, methoxy (2,2,2-trifluoroethoxy) methane, methoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, Toxi (2-fluoroethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, bis (2-fluoroethoxy) methane, (2 -Fluoroethoxy) (2,2,2-trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, bis (2,2,2-trifluoroethoxy) Methane, (1,1,2,2-tetrafluoroethoxy) (2,2,2-trifluoroethoxy) methane, bis (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, ethoxymethoxyethane , (2-fluoroethoxy) methoxyethane, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1, 2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ) Ethane, bis (2-fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) Ethane, bis (2,2,2-trifluoroethoxy) ethane, (1,1,2,2-tetrafluoroethoxy) (2,2,2-trifluoroethoxy) ethane, bis (1,1,2, 2-tetrafluoroethoxy) ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethyl Glycol dimethyl ether.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.

The content of the ether compound is usually 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less, in 100% by volume of the non-aqueous solvent. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less. If it is this range, it will be easy to ensure the improvement effect of the ionic conductivity derived from the improvement of the lithium ion dissociation degree of a chain ether, and a viscosity fall.

[4. Electrolytes]
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.
Inorganic lithium salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiNbF ₆ , LiTaF ₆ , LiWF ₇ ;
Lithium fluorophosphates such as LiPO ₃ F and LiPO ₂ F ₂ ;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃ SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ Sulfonic acid lithium salts such as CF ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium imide salts such as lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) ;
Lithium metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C _{2 F 5, LiBF 3 C 3} F 7, LiBF 2 (CF 3) 2, LiBF 2 (C 2 F 5) 2, LiBF 2 (CF 3 SO 2) 2, LiBF 2 (C 2 F 5 SO 2) 2 Fluorine-containing organic lithium salts such as;

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiPO ₂ F ₂ , FSO ₃ Li, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN ( CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, lithium Tris (oxalato) phosphate, L _{BF 3 CF 3, LiBF 3 C} 2 F 5, LiPF 3 (CF 3) 3, LiPF 3 (C 2 F 5) 3 or the like is output characteristics and high-rate discharge characteristics, high-temperature storage characteristics, the effect of improving the cycle characteristics and the like It is particularly preferable because of

These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using 2 or more types together is LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li, Li
The combination of PF ₆ and LiPO ₂ F ₂ has the effect of improving load characteristics and cycle characteristics. Among these, the combined use of LiPF ₆ and LiBF ₄ is preferable from the viewpoint of obtaining a gas generation suppressing effect.

When LiPF ₆ and LiBF ₄ are used in combination, the concentration of LiBF ₄ with respect to 100% by mass of the entire non-aqueous electrolyte solution is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The upper limit is usually 10% by mass or less, preferably 5% by mass or less, usually 0.001% by mass or more, preferably 0.01% by mass or more, with respect to the electrolytic solution. Within this range, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature characteristics are improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. may be reduced.

Here, the preparation of the electrolyte solution in the case of incorporating the LiPO ₂ F ₂ in the electrolyte solution, Ya separately active material method and later be added to the electrolytic solution containing LiPF ₆ and LiPO ₂ F ₂ synthesized by a known method A method of generating LiPO ₂ F ₂ in the system when water is allowed to coexist in a battery component such as an electrode plate and assembling a battery using an electrolyte containing LiPF ₆ is used. You may use the method of.

The method for measuring the content of LiPO ₂ F ₂ in the non-aqueous electrolyte solution and the non-aqueous electrolyte secondary battery is not particularly limited, and any known method can be used. Specific examples include ion chromatography and F nuclear magnetic resonance spectroscopy.
Another preferred example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has the effect of suppressing deterioration due to high-temperature storage. As the organic lithium salt, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) _3, preferably a _{LiPF 3 (C 2 F 5)} 3 , etc. In this case, the ratio of the organic lithium salt to 100% by mass of the entire non-aqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and preferably 30% by mass or less. Especially preferably, it is 20 mass% or less.

  The concentration of these lithium salts in the non-aqueous electrolyte solution is not particularly limited as long as the effects of the present invention are not impaired. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and further preferably 0.5 mol / L or more. Preferably it is 3 mol / L or less, More preferably, it is 2.5 mol / L or less, More preferably, it is 2.0 mol / L or less. If it is this range, effects, such as a low temperature characteristic, cycling characteristics, and a high temperature characteristic, will improve. On the other hand, if the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity. May decrease.

[5. Auxiliary]
In the non-aqueous electrolyte secondary battery of the present invention, an auxiliary agent may be appropriately used according to the purpose other than the acid anhydride. As the auxiliary agent, the cyclic carbonate having an unsaturated bond shown below, the unsaturated cyclic carbonate having a fluorine atom, the compound having a carbon-carbon triple bond, the cyclic sulfonic acid ester, the compound having a cyano group, an acid anhydride, An overcharge inhibitor, other auxiliaries and the like can be mentioned.

[5.1 Cyclic carbonate having an unsaturated bond]
In the non-aqueous electrolyte of the present invention, a cyclic carbonate having an unsaturated bond (hereinafter referred to as “unsaturated cyclic”) is formed in order to form a film on the negative electrode surface of the non-aqueous electrolyte secondary battery and to extend the life of the battery. May be abbreviated as “carbonate”).
The unsaturated cyclic carbonate is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon double bond or a cyclic carbonate having a carbon-carbon triple bond described later. Any unsaturated carbonate can be used. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.

Examples of the unsaturated cyclic carbonate include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond, phenyl carbonates, vinyl carbonates, allyl carbonates, catechol carbonates, and the like. It is done.
As vinylene carbonates, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4 , 5-diallyl vinylene carbonate and the like.

  Specific examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon double bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene Examples thereof include carbonate and 4-methyl-5-allylethylene carbonate.

  Among them, preferred unsaturated cyclic carbonates for use in combination include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5- Diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate, 4-methyl-5-allyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate is more preferably used because it forms a stable interface protective film.

  The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. The molecular weight of the unsaturated cyclic carbonate is more preferably 80 or more, and more preferably 150 or less. The production method of the unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method.

An unsaturated cyclic carbonate may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios.
Further, the content of the unsaturated cyclic carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of the unsaturated cyclic carbonate is 100% by mass of the non-aqueous electrolyte solution, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. Moreover, Preferably it is 5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exhibited. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

[5.2 Unsaturated cyclic carbonate having fluorine atom]
As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes abbreviated as “fluorinated unsaturated cyclic carbonate”). The number of fluorine atoms contained in the fluorinated unsaturated cyclic carbonate is not particularly limited as long as it is 1 or more. Among them, the number of fluorine atoms is usually 6 or less, preferably 4 or less, and one or two is most preferable.

Examples of the fluorinated unsaturated cyclic carbonate include fluorinated vinylene carbonate derivatives, fluorinated ethylene carbonate derivatives substituted with an aromatic ring or a substituent having a carbon-carbon double bond.
Fluorinated vinylene carbonate derivatives include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5- And vinyl vinylene carbonate.

  Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon double bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5. -Vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate 4,5-diflu B-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4- Examples thereof include phenylethylene carbonate.

  Among them, particularly preferred fluorinated unsaturated cyclic carbonates to be used in combination include 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-vinylvinylene carbonate, 4-allyl-5-fluoro. Vinylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4 -Vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinyl Tylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate provide stable interface protective coatings Since it forms, it is used more suitably.

The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the fluorinated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the fluorinated unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method. The molecular weight is more preferably 100 or more, and more preferably 200 or less.

A fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
Further, the content of the fluorinated unsaturated cyclic carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of the fluorinated unsaturated cyclic carbonate is usually in 100% by mass of the nonaqueous electrolytic solution, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. Moreover, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exhibited. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

[5.3 Compound having carbon-carbon triple bond]
In the non-aqueous electrolyte solution of the present invention, a compound having a carbon-carbon triple bond can be contained in order to form a film on the surface of the negative electrode of the non-aqueous electrolyte secondary battery and to extend the life of the battery. The compound having a carbon-carbon triple bond is not particularly limited as long as it is a compound having a carbon-carbon triple bond, but a chain compound having a carbon-carbon triple bond and a ring having a carbon-carbon triple bond. Classified as a compound.
As the chain compound having a carbon-carbon triple bond, one or more alkyne derivatives represented by the following general formula (1) and / or formula (2) are preferably used.

(In the formula _{(1) ~ (2),} R 1 ~R 9 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, 3 to 6 carbon atoms a cycloalkyl group or having 6 to 12 carbon atoms R ₂ and R ₃ , R ₅ and R ₆ , R ₇ and R ₈ may be bonded to each other to form a cycloalkyl group having 3 to 6 carbon atoms, where x and y are each an aryl group. Each independently represents an integer of 1 or 2. Y ₁ and Y ₂ are each represented by the formula (3), and Y ₁ and Y ₂ may be the same or different, and Z ₁ is a hydrogen atom. And an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms.)

Among the compounds represented by the general formula (1), 2-propynylmethyl carbonate, 1-methyl-2-propynylmethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-propynylethyl carbonate, 1-methyl 2-propynyl ethyl carbonate, 1,1-dimethyl-2-propynyl ethyl carbonate, 2-butynyl methyl carbonate, 1-methyl-2-butynyl methyl carbonate, 1,1-dimethyl-2-butynyl methyl carbonate -2-propynyl formate, 1-methyl-2-propynyl formate, 1,1-dimethyl-2-propynyl formate, 2-butynyl formate, 1-methyl-2-butynyl formate, formic acid-1,1 -Dimethyl-2-butynyl acetate-2-propynyl acetate, 1-methyl-2-propynyl acetate 1,1-dimethyl-2-propynyl acetate, 2-butynyl acetate, 1-methyl-2-butynyl acetate, 1,1-dimethyl-2-butynyl acetate, 2-propynylmethyl oxalate, 1-methyl 2-propynylmethyl oxalate, 1,1-dimethyl-2-propynylmethyl oxalate, 2-butynylmethyl oxalate, 1-methyl-2-butynylmethyl oxalate, 1,1-dimethyl-2-buty Nylmethyl oxalate, 2-propynyl ethyl oxalate, 1-methyl-2-propynyl ethyl oxalate, 1,1-dimethyl-2-propynyl ethyl oxalate, 2-butynyl ethyl oxalate, 1-methyl-2- Butynylethyl oxalate, 1,1-dimethyl-2-butynylethyl oxalate, methanesulfonic acid -Propynyl, methanesulfonic acid-1-methyl-2-propynyl, methanesulfonic acid-1,1-dimethyl-2-propynyl, methanesulfonic acid-2-butynyl, methanesulfonic acid-1-methyl-2-butynyl, methane Sulfonic acid-1,1-dimethyl-2-butynyl, trifluoromethanesulfonic acid-2-propynyl, trifluoromethanesulfonic acid-1-methyl-2-propynyl, trifluoromethanesulfonic acid-1,1-dimethyl-2-propynyl, Trifluoromethanesulfonic acid-2-butynyl, trifluoromethanesulfonic acid-1-methyl-2-butynyl, trifluoromethanesulfonic acid-1,1-dimethyl-2-butynyl, trifluoroethanesulfonic acid-2-propynyl, trifluoroethane Sulfonic acid-1-methyl-2-propi Nyl, trifluoroethanesulfonic acid-1,1-dimethyl-2-propynyl, trifluoroethanesulfonic acid-2-butynyl, trifluoroethanesulfonic acid-1-methyl-2-butynyl, trifluoroethanesulfonic acid-1, 1-dimethyl-2-butynyl, benzenesulfonic acid-2-propynyl, benzenesulfonic acid-1-methyl-2-propynyl, benzenesulfonic acid-1,1-dimethyl-2-propynyl, benzenesulfonic acid-2-butynyl, Benzenesulfonic acid-1-methyl-2-butynyl, benzenesulfonic acid-1,1-dimethyl-2-butynyl, p-toluenesulfonic acid-2-propynyl, p-toluenesulfonic acid-1-methyl-2-propynyl, p-Toluenesulfonic acid-1,1-dimethyl-2-propynyl, p-toluene 2-butynyl phonate, p-toluenesulfonic acid-1-methyl-2-butynyl, p-toluenesulfonic acid-1,1-dimethyl-2-butynyl, methylsulfuric acid-2-propynyl, methylsulfuric acid-1-methyl 2-propynyl, methyl sulfate-1,1-dimethyl-2-propynyl, methyl sulfate-2-butynyl, methyl sulfate-1-methyl-2-butynyl, methyl sulfate-1,1-dimethyl-2-propynyl, ethyl 2-propynyl sulfate, ethyl sulfate-1-methyl-2-propynyl, ethyl sulfate-1,1-dimethyl-2-propynyl, ethyl sulfate-2-butynyl, ethyl sulfate-1-methyl-2-butynyl, ethyl sulfate It is preferable to contain at least one selected from -1,1-dimethyl-2-butynyl. In particular, 2-propynylmethyl carbonate, 1-methyl-2-propynylmethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-propynylethyl carbonate, 2-butynylmethyl carbonate, formic acid-2-propynyl, formic acid -1-methyl-2-propynyl, formic acid-1,1-dimethyl-2-propynyl, formate-2-butynyl acetate, 2-propynyl acetate, 1-methyl-2-propynyl acetate, 1,1-dimethyl acetate -2-propynyl, 2-butynyl acetate, 2-propynyl methyl oxalate, 1-methyl-2-propynyl methyl oxalate, 1,1-dimethyl-2-propynyl methyl oxalate, 2-butynyl methyl oxalate, Methanesulfonic acid-2-propynyl, methanesulfonic acid-1-methyl-2 Propynyl, methanesulfonic acid-1,1-dimethyl-2-propynyl, methanesulfonic acid-2-butynyl, methanesulfonic acid-1-methyl-2-butynyl, methylsulfuric acid-2-propynyl, methylsulfuric acid-1-methyl- It is more preferable to contain one or more selected from 2-propynyl, methyl sulfate-1,1-dimethyl-2-propynyl, and methyl sulfate-2-butynyl.

  Among the compounds represented by the general formula (2), di (2-propynyl) carbonate, di (2-butynyl) carbonate, di (1-methyl-2-propynyl) carbonate, di (1-methyl-2-butynyl) ) Carbonate, di (1,1-dimethyl-2-propynyl) carbonate, di (1,1-dimethyl-2-butynyl) carbonate, di (2-propynyl) oxalate, di (2-butynyl) oxalate, di (1 -Methyl-2-propynyl) oxalate, di (1-methyl-2-butynyl) oxalate, di (1,1-dimethyl-2-propynyl) oxalate, di (1,1-dimethyl-2-butynyl) oxalate, di (2-propynyl) sulfite, di (2-butynyl) sulfite, di (1-methyl-2-propynyl) sulfite, (1-methyl-2-butynyl) sulfite, di (1,1-dimethyl-2-propynyl) sulfite, di (1,1-dimethyl-2-butynyl) sulfite, di (2-propynyl) sulfuric acid, Di (2-butynyl) sulfuric acid, di (1-methyl-2-propynyl) sulfuric acid, di (1-methyl-2-butynyl) sulfuric acid, di (1,1-dimethyl-2-propynyl) sulfuric acid, di (1, It is preferable to contain one or more selected from (1-dimethyl-2-butynyl) sulfuric acid. In particular, from di (2-propynyl) carbonate, di (2-butynyl) carbonate, di (2-propynyl) oxalate, di (2-butynyl) oxalate, di (2-propynyl) sulfuric acid, di (2-butynyl) sulfuric acid It is more preferable to contain one or more selected.

  Among the alkyne derivatives, the most preferred compounds are 2-propynylmethyl carbonate, 2-propynylethyl carbonate, 2-butynylmethyl carbonate, formate-2-propynyl, formate-2-butynyl, acetate-2-propynyl, acetate- 2-butynyl, 2-propynylmethyl oxalate, 2-butynylmethyl oxalate, methanesulfonic acid-2-propynyl, methanesulfonic acid-2-butynyl, methanesulfonic acid-1-methyl-2-butynyl, methylsulfuric acid 2-propynyl, methyl sulfate-2-butynyl, di (2-propynyl) carbonate, di (2-butynyl) carbonate, di (2-propynyl) oxalate, di (2-butynyl) oxalate, di (2-propynyl) sulfuric acid , At least selected from di (2-butynyl) sulfuric acid It is a species or more compounds.

The compounds represented by the general formula (1) or (2) may be used alone or in combination of two or more in any combination and ratio. Further, the content of the compound represented by the general formula (1) or (2) is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired.
The content of the compound represented by the general formula (1) or (2) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0% in 100% by mass of the nonaqueous electrolytic solution. 0.1% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

  Moreover, when the compound which has a carbon-carbon triple bond is a cyclic compound, it is preferable that it is a compound represented by following General formula (4).

(In Formula (4), X ¹ and X ³ are CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , or P—R ¹ . X ² represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . In the formula, R and R ¹ are each independently a hydrogen atom, a halogen atom, or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and a plurality of R and / or R ¹ are present. When present, they may be the same as or different from each other, R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and a plurality of R ² are present. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ⁴ is an optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and a plurality of R ⁴ may be the same or different from each other, and l and m are each independently Represents an integer of 0 or more.)
In General Formula (4), X ¹ and X ³ are not particularly limited as long as they are within the range described in General Formula (4), but each independently represents CR ¹ ₂ , O, S, or N—R ^1. More preferred. X ² is not particularly limited as long as it is within the range described in the general formula (4), but C═O, S═O, S (═O) ₂ , P (═O) —R ^2, or P (═O ) -OR ³ is more preferred. R and R ¹ are not particularly limited as long as they are within the range described in the general formula (4), but preferably each independently a hydrogen atom, a fluorine atom, or a saturated aliphatic hydrocarbon which may have a substituent. Group, an unsaturated aliphatic hydrocarbon group which may have a substituent, or an aromatic hydrocarbon group which may have a substituent.

R ² and R ⁴ are not particularly limited as long as they are within the range described in the general formula (4), but preferably each independently represents a saturated aliphatic hydrocarbon group or a substituent that may have a substituent. Examples thereof include an unsaturated aliphatic hydrocarbon which may have, or an aromatic hydrocarbon / aromatic heterocycle which may have a substituent.
R ³ is not particularly limited as long as it is within the range described in the general formula (4), but preferably Li, a saturated aliphatic hydrocarbon which may have a substituent, or an unsaturated which may have a substituent Examples thereof include an aliphatic hydrocarbon or an aromatic hydrocarbon / aromatic heterocycle which may have a substituent.

Substituents of saturated aliphatic hydrocarbons which may have substituents, unsaturated aliphatic hydrocarbons which may have substituents, aromatic hydrocarbons and aromatic heterocycles which may have substituents Is not particularly limited, but preferably has a saturated aliphatic hydrocarbon group, which may have a substituent such as a halogen atom, carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, phosphorous acid, etc. And an unsaturated aliphatic hydrocarbon group which may be substituted, an ester of an aromatic hydrocarbon group which may have a substituent, and the like, more preferably a halogen atom, and most preferably a fluorine atom.

  Preferable saturated aliphatic hydrocarbons include, specifically, methyl group, ethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl group, 1,1-difluoroethyl. Group, 1,2-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl group, 2,2,2-trifluoroethyl group A phenyl group, a cyclopentyl group, and a cyclohexyl group are preferred.

Specific preferred unsaturated aliphatic hydrocarbons include ethenyl, 1-fluoroethenyl, 2-fluoroethenyl, 1-methylethenyl, 2-propenyl, and 2-fluoro-2-propenyl. 3-fluoro-2-propenyl group, ethynyl group, 2-fluoroethynyl group, 2-propynyl group, and 3-fluoro-2propynyl group are preferable.
Preferred aromatic hydrocarbons include phenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluorophenyl group, 3,5-difluorophenyl group, 2, 4 , 6-trifluorophenyl group is preferred.

Preferred aromatic heterocycles are 2-furanyl group, 3-furanyl group, 2-thiophenyl group, 3-thiophenyl group, 1-methyl-2-pyrrolyl group, and 1-methyl-3-pyrrolyl group.
Among these, a methyl group, an ethyl group, a fluoromethyl group, a trifluoromethyl group, a 2-fluoroethyl group, a 2,2,2-trifluoroethyl group, an ethenyl group, an ethynyl group, and a phenyl group are preferable.

More preferably, a methyl group, an ethyl group, and an ethynyl group are preferable.
Moreover, it is preferable that R is a hydrogen atom, a fluorine atom, or an ethynyl group from the both sides of the reactivity and stability of the compound of the general formula (4). In the case of other substituents, the reactivity is lowered and the expected properties may be lowered. Moreover, when it is a halogen atom other than a fluorine atom, the reactivity is too high and there is a possibility that the side reaction increases.

The number of fluorine atoms or ethynyl groups in R is preferably within 2 in total. If the number is too large, the compatibility with the electrolytic solution may be deteriorated, and the reactivity may be too high to increase the side reaction.
l and m are not particularly limited as long as they are in the range described in the general formula (4), but are preferably independently 0 or 1, more preferably 1 = m = 1 or m = 1, l = 0.

Of these, m = 1 and l = 0 are more preferable. When both l and m are 0, stability deteriorates due to ring distortion, and the reactivity may become too high, resulting in an increase in side reactions. Further, if m = 2 or more, or even if m = 1, if 1 = 1 or more, the chain may be more stable than the ring, and the desired characteristics may not be exhibited. There is.
Further, in the formula (4), ^{X 1} and ^{X 3} are, ^CR _{1 2} or O are more preferred. In cases other than these, the reactivity may be too high and side reactions may increase.

The molecular weight of the compound represented by the general formula (4) is preferably 50 or more. Moreover, Preferably it is 500 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily.
The molecular weight is more preferably 100 or more, and more preferably 200 or less. If it is this range, it will be easy to ensure further the solubility of General formula (4) with respect to a non-aqueous electrolyte solution, and the effect of this invention will be fully further easily expressed.

More preferably, a plurality of Rs are all hydrogen atoms. In this case, the side reaction is most likely to be suppressed while maintaining the expected characteristics. X ² is C═O or S═O, and at least one of X ¹ and X ³ is O, or X ² is S (═O) ₂ , P (═O) —R. ² or P (═O) —OR ³ , X ¹ and X ³ are both O or CH ₂ , or ^one of X ¹ and X ³ is O and the other is CH ₂ Is preferred. When X ² is C═O or S═O, if both X ¹ and X ³ are CH ₂ , the reactivity may be too high and side reactions may increase.
Specific examples of the compound represented by the general formula (4) are shown below.

  Of the compounds represented by the general formula (4), the compound represented by the general formula (5) is preferable from the viewpoint of ease of industrial production.

In the above formula (5), ^{X 2} is has the same meaning as ^{X 2} in the formula (4), except for ^CR _{1 2.} That, C = O, S = O , S (= O) 2, P (= O) -R 2, or P (= O) -O
R ³ is represented. R ² and R ³ are also synonymous with the formula (4). Specific examples of these compounds having preferable conditions are shown below.

  The said compound which has a carbon-carbon triple bond may be used individually by 1 type, or may have 2 or more types together by arbitrary combinations and ratios. The content of the compound having a carbon-carbon triple bond is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of the compound having a carbon-carbon triple bond is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more, in 100% by mass of the non-aqueous electrolyte solution. Moreover, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

[5.4 Cyclic sulfonate ester]
In the nonaqueous electrolytic solution of the present invention, it is also preferable to use a cyclic sulfonate ester. The molecular weight of the cyclic sulfonic acid ester compound is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 100 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the cyclic sulfonic acid ester compound with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the cyclic sulfonate compound is not particularly limited, and can be produced by arbitrarily selecting a known method.

In the non-aqueous electrolyte solution of the present invention, examples of the cyclic sulfonate compound that can be used include:
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-methyl-1,3-propane sultone 2-methyl-1,3-propane sultone, 3-methyl-1,3-propane sultone, 1,4-butane sultone, 1-fluoro-1,4-butane sultone, 2-fluoro-1,4-butane sultone, 3, -Fluoro-1,4-butane sultone, 4-fluoro-1,4-butane sultone, 1-methyl-1,4-butane sultone, 2-methyl-1,4-butane sultone, 3-methyl-1,4-butane sultone, 4 -Methyl-1,4-butane sultone, 1,5-pentane sultone, 1-fluoro-1,5-pentane sultone, 2-fluoro-1,5 Pentane sultone, 3-fluoro-1,5-pentane sultone, 4-fluoro-1,5-pentane sultone, 5-fluoro-1,5-pentane sultone, 1-methyl-1,5-pentane sultone, 2-methyl Monosulfonic acid ester compounds such as -1,5-pentanthruton, 3-methyl-1,5-pentanthruton, 4-methyl-1,5-pentanthruton, 5-methyl-1,5-pentanthruton;
And disulfonic acid ester compounds such as methylene methane disulfonate, ethylene methane disulfonate, and ethylene ethane disulfonate.

  Among these, 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1,4-butane sultone, Methylene methane disulfonate and ethylene methane disulfonate are preferable from the viewpoint of improving storage characteristics. 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro -1,3-propane sultone is more preferred.

  It is also preferable to use a cyclic sulfonic acid ester having a carbon-carbon double bond. Examples of the cyclic sulfonic acid ester having a carbon-carbon double bond include 1-propene-1,3-sultone, 2-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2 -Fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1-methyl-1-propene-1,3-sultone, 2-methyl-1-propene-1 , 3-sultone, 3-methyl-1-propene-1,3-sultone, 1-butene-1,4-sultone, 2-butene-1,4-sultone, 3-butene-1,4-sultone, 1 -Fluoro-1-butene-1,4-sultone, 2-fluoro-1-butene-1,4-sultone, 3-fluoro-1-butene-1,4-sultone, 4-fluoro-1-butene-1 , 4-sultone, 1-methyl -1-butene-1,4-sultone, 2-methyl-1-butene-1,4-sultone, 3-methyl-1-butene-1,4-sultone, 4-methyl-1-butene-1,4 -Sultone etc. can be mentioned.

Of these, 1-propene-1,3-sultone, 1-butene-1,4-sultone, 2-butene-1,4-sultone, and 3-butene-1,4-sultone are more preferable.
A cyclic sulfonic acid ester compound may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
There is no restriction | limiting in content of the cyclic sulfonate ester compound with respect to the whole nonaqueous electrolyte solution of this invention, Although it is arbitrary unless the effect of this invention is impaired remarkably, Usually, it is 0.8 with respect to the nonaqueous electrolyte solution of this invention. 001% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Let When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, and gas generation suppression are further improved.

[5.5 Compound having cyano group]
In the nonaqueous electrolytic solution of the present invention, it is also preferable to use a compound having a cyano group. Here, the compound having a cyano group is not particularly limited as long as it is a compound having a cyano group in the molecule, but a compound represented by the general formula (6) is more preferable.

(In the general formula (6), T represents an organic group composed of one or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom and a halogen atom. , X ⁴ is an n-valent organic group having 1 to 10 carbon atoms which may have a substituent, wherein n is an integer of 1 or more, and when n is 2 or more, a plurality of Ts are the same as each other Or different.)
The molecular weight of the compound having a cyano group is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more, more preferably 80 or more, still more preferably 100 or more, and 200 or less. If it is this range, it will be easy to ensure the solubility of the compound which has a cyano group with respect to nonaqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the compound having a cyano group is not particularly limited, and can be produced by arbitrarily selecting a known method.

Specific examples of the compound represented by the general formula (6) include, for example,
Acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, 2,2-dimethylbutyronitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile , Acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitryl, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile, 2,3 Difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3,3′-oxydipropionitrile, 3,3 ′ -Compounds having one cyano group such as thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, pentafluoropropionitrile;

Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimonitrile, suberonitrile, azeronitrile, sebaconitrile, undecandinitrile, dodecandinitrile, methylmalononitrile, ethylmalononitrile, i-propylmalononitrile, t-butylmalononitrile, methylsk Sinonitrile, 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, trimethylsuccinonitrile, tetramethylsuccinonitrile, 3,3 ′-(ethylenedioxy) dipropionitrile, 3,3 ′ -A compound having two cyano groups such as (ethylenedithio) dipropionitrile;
Compounds having three cyano groups such as 1,2,3-tris (2-cyanoethoxy) propane and tris (2-cyanoethyl) amine;

Cyanate compounds such as methyl cyanate, ethyl cyanate, propyl cyanate, butyl cyanate, pentyl cyanate, hexyl cyanate, heptyl cyanate;
Methyl thiocyanate, ethyl thiocyanate, propyl thiocyanate, butyl thiocyanate, pentyl thiocyanate, hexyl thiocyanate, heptyl thiocyanate, methanesulfonyl cyanide, ethanesulfonyl cyanide, propanesulfonyl cyanide, butanesulfonyl cyanide, pentanesulfonyl cyanide, hexanesulfonyl cyanide , Heptanesulfonylcyanide, methylsulfurocyanidate, ethylsulfurocyanidate, propylsulfurocyanidate, butylsulfurocyanidate, pentylsulfurocyanidate, hexylsulfurocyanidate, heptylsulfur Sulfur-containing compounds such as frocyanidates;

  Cyanodimethylphosphine, cyanodimethylphosphine oxide, methyl cyanomethylphosphinate, methyl cyanomethylphosphinate, dimethylphosphinic acid cyanide, dimethylphosphinic acid cyanide, dimethyl phosphophosphonate, dimethyl cyanophosphonite, cyanomethyl methylphosphonate, methylphosphonite And phosphorus-containing compounds such as cyanomethyl acid, cyanodimethyl phosphate, and cyanodimethyl phosphite.

Of these, acetonitrile, propionitrile, butyronitrile, i-butyronitrile, valeronitrile, i-valeronitrile, lauronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, Pimeronitrile, suberonitrile, azeronitrile, sebaconitrile, undecandinitrile, and dodecanedinitrile are preferable from the viewpoint of improving the storage characteristics. A compound having two cyano groups such as nitrile is more preferable.

The compound which has a cyano group may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
There is no restriction | limiting in content of the compound which has a cyano group with respect to the whole nonaqueous electrolyte solution of this invention, Although it is arbitrary unless the effect of this invention is impaired remarkably, Usually, it is 0.8 with respect to the nonaqueous electrolyte solution of this invention. 001% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Let When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, and gas generation are further improved.

[5.6 Acid anhydride]
In the non-aqueous electrolyte solution of the present invention, it is also preferable to use an acid anhydride. Examples of the acid anhydride include carboxylic acid anhydrides, sulfonic acid anhydrides, and anhydrides of carboxylic acid and sulfonic acid, and preferably carboxylic acid anhydrides and sulfonic acid anhydrides.
Specific examples of carboxylic acid anhydrides include acetic anhydride, propionic anhydride, butyric anhydride, crotonic anhydride, trifluoroacetic anhydride, pentafluoropropionic anhydride, succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, Glutaconic anhydride, itaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydro Phthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phenylsuccinic anhydride, 2-phenylglutaric anhydride, phthalic anhydride, pyromellitic anhydride, fluorosuccinic anhydride, tetrafluorosuccinic acid An acid anhydride etc. can be mentioned. Among these, succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, itaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, fluorosuccinic anhydride, tetrafluorosuccinic anhydride are charged and discharged. This is preferable from the viewpoint of the balance between the improvement in efficiency and the effect of suppressing gas generation.

  Specific examples of the sulfonic acid anhydride include methanesulfonic acid anhydride, ethanesulfonic acid anhydride, propanesulfonic acid anhydride, butanesulfonic acid anhydride, pentanesulfonic acid anhydride, hexanesulfonic acid anhydride, vinylsulfonic acid anhydride. , Benzenesulfonic anhydride, trifluoromethanesulfonic anhydride, 2,2,2-trifluoroethanesulfonic anhydride, pentafluoroethanesulfonic anhydride, 1,2-ethanedisulfonic anhydride, 3-propane Disulfonic anhydride, 4-butanedisulfonic anhydride, 2-benzenedisulfonic anhydride, tetrafluoro-1,2-ethanedisulfonic anhydride, hexafluoro-1,3-propanedisulfonic anhydride, octafluoro- 1,4-butanedisulfonic anhydride, 3-fluoro-1,2-benzene Examples include sulfonic acid anhydride, 4-fluoro-1,2-benzenedisulfonic acid anhydride, 3,4,5,6-tetrafluoro-1,2-benzenedisulfonic acid anhydride, and ethionic acid cycloanhydride. it can. Among these, methanesulfonic anhydride, ethanesulfonic anhydride, propanesulfonic anhydride, butanesulfonic anhydride, vinylsulfonic anhydride, benzenesulfonic anhydride, trifluoromethanesulfonic anhydride, 2,2 , 2-trifluoroethanesulfonic anhydride, pentafluoroethanesulfonic anhydride, 1,2-ethanedisulfonic anhydride, 3-propanedisulfonic anhydride, 1,2-benzenedisulfonic anhydride From the viewpoint of the balance between the improvement of the gas and the effect of suppressing gas generation.

Specific examples of carboxylic acid and sulfonic acid anhydrides include acetic acid methanesulfonic acid anhydride,
Acetic acid ethanesulfonic acid anhydride, acetic acid propanesulfonic acid anhydride, propionic acid methanesulfonic acid anhydride, propionic acid ethanesulfonic acid anhydride, propionic acid propanesulfonic acid anhydride, trifluoroacetic acid methanesulfonic acid anhydride, trifluoroacetic acid Ethanesulfonic acid anhydride, trifluoroacetic acid propanesulfonic acid anhydride, acetic acid trifluoromethanesulfonic acid anhydride, acetic acid 2,2,2-trifluoroethanesulfonic acid anhydride, acetic acid pentafluoroethanesulfonic acid anhydride, trifluoroacetic acid Trifluoromethanesulfonic anhydride, trifluoroacetic acid 2,2,2-trifluoroethanesulfonic anhydride, trifluoroacetic acid pentafluoroethanesulfonic anhydride, 3-sulfopropionic anhydride, 2-methyl-3-sulfo Propionic anhydride, -Dimethyl-3-sulfopropionic anhydride, 2-ethyl-3-sulfopropionic anhydride, 2,2-diethyl-3-sulfopropionic anhydride, 2-fluoro-3-sulfopropionic anhydride, 2 , 2-Difluoro-3-sulfopropionic anhydride, 2,2,3,3-tetrafluoro-3-sulfopropionic anhydride, 2-sulfobenzoic anhydride, 3-fluoro-2-sulfobenzoic anhydride 4-fluoro-2-sulfobenzoic anhydride, 5-fluoro-2-sulfobenzoic anhydride, 6-fluoro-2-sulfobenzoic anhydride, 3,6-difluoro-2-sulfobenzoic anhydride 3,4,5,6-tetrafluoro-2-sulfobenzoic anhydride, 3-trifluoromethyl-2-sulfobenzoic anhydride, 4-trifluoromethyl-2-sulfoan Kosan anhydride, 5-trifluoromethyl-2-sulfobenzoic acid anhydride, mention may be made of 6-trifluoromethyl-2-sulfobenzoic anhydride and the like.

  Among these, acetic acid methanesulfonic acid anhydride, acetic acid ethanesulfonic acid anhydride, acetic acid propanesulfonic acid anhydride, propionic acid methanesulfonic acid anhydride, propionic acid ethanesulfonic acid anhydride, propionic acid propanesulfonic acid anhydride, Fluoroacetic acid methanesulfonic acid anhydride, trifluoroacetic acid ethanesulfonic acid anhydride, trifluoroacetic acid propanesulfonic acid anhydride, acetic acid trifluoromethanesulfonic acid anhydride, acetic acid 2,2,2-trifluoroethanesulfonic acid anhydride, acetic acid Pentafluoroethanesulfonic acid anhydride, trifluoroacetic acid trifluoromethanesulfonic acid anhydride, trifluoroacetic acid 2,2,2-trifluoroethanesulfonic acid anhydride, trifluoroacetic acid pentafluoroethanesulfonic acid anhydride, 2-sulfobenzoic acid Acid anhydride, 3 Fluoro-2-sulfobenzoic anhydride, 4-fluoro-2-sulfobenzoic anhydride, 5-fluoro-2-sulfobenzoic anhydride, 6-fluoro-2-sulfobenzoic anhydride have high temperature storage characteristics. It is preferable from the point of balance between improvement and gas generation suppression effect.

An acid anhydride may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
In addition, the content of the acid anhydride in the electrolytic solution used in the present invention is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass with respect to the whole non-aqueous solvent. % Or more, usually 10% by mass or less, preferably 3% by mass or less, more preferably 1.5% by mass or less, still more preferably 1% by mass or less, particularly preferably less than 1% by mass, and particularly preferably 0. It is 9 mass% or less, Most preferably, it is 0.8 mass% or less. When the addition amount is within the above range, the gas generation suppressing effect is sufficient, and the gas generation derived from the acid anhydride is suppressed, so that the effects of the present invention can be sufficiently exhibited.

[5.7 Overcharge inhibitor]
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively suppress battery explosion / ignition when the non-aqueous electrolyte secondary battery is in an overcharged state or the like. .
As an overcharge prevention agent,
Aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran;
Partially fluorinated products of the above aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene;
And fluorine-containing anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, and 3,5-difluoroanisole;

Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable. These may be used alone or in combination of two or more.
When two or more types are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated product, cyclohexylbenzene, t-butylbenzene And at least one selected from oxygen-free aromatic compounds such as t-amylbenzene and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran are used in combination with overcharge prevention characteristics and high temperature. It is preferable from the point of balance of storage characteristics.

  The content of the overcharge inhibitor is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is preferably 0.1% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. If it is this range, it will be easy to fully express the effect of an overcharge inhibiting agent, and it will be easy to avoid the situation where the characteristics of batteries, such as a high temperature storage characteristic, fall. The overcharge inhibitor is more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and more preferably 3% by mass or less, still more preferably. Is 2% by mass or less.

[5.8 Other auxiliary agents]
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention.
As other auxiliaries,
Carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate;
Spiro compounds such as 2,4,8,10-tetraoxaspiro [5.5] undecane and 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane;
Ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, Sulfur-containing compounds such as N, N-diethylmethanesulfonamide;
Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide;

Hydrocarbon compounds such as heptane, octane, nonane, decane, cycloheptane;
Fluorine-containing aromatic compounds such as fluorobenzene, difluorobenzene, hexafluorobenzene and benzotrifluoride;
Methyldimethylphosphinate, ethyldimethylphosphinate, ethyldiethylphosphinate, trimethylphosphonoformate, triethylphosphonoformate, trimethylphosphonoacetate, triethylphosphonoacetate, trimethyl-3-phosphonopropionate, triethyl-3 -Phosphorus-containing compounds such as phosphonopropionate;

These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.
Among these, ethylene sulfite, methyl fluorosulfonate, methyl methanesulfonate, methyl ethanesulfonate, ethyl methanesulfonate, busulfan, 1,4-butanediol bis (2,2,2-trifluoroethanesulfonate), etc. This sulfur-containing compound is particularly preferable because it has a large effect of improving capacity retention characteristics and cycle characteristics after high-temperature storage.

  The content of other auxiliaries is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. Within this range, the effects of other auxiliaries can be sufficiently exhibited, and it is easy to avoid a situation in which battery characteristics such as high-load discharge characteristics deteriorate. The content of other auxiliaries is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 3% by mass or less, and further preferably 1% by mass or less. .

  The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte secondary battery according to the present invention. Specifically, the components of the non-aqueous electrolyte such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte is prepared from the substantially isolated one by the method described below. In the case of a non-aqueous electrolyte solution in a non-aqueous electrolyte secondary battery obtained by pouring into a separately assembled battery, the components of the non-aqueous electrolyte solution of the present invention are individually placed in the battery, When the same composition as the non-aqueous electrolyte of the present invention is obtained by mixing in the battery, further, the compound constituting the non-aqueous electrolyte of the present invention is generated in the non-aqueous electrolyte secondary battery, The case where the same composition as the non-aqueous electrolyte solution of the present invention is obtained is also included.

[II. Negative electrode]
The negative electrode active material used for the negative electrode is described below. The negative electrode active material is not particularly limited as long as it can occlude and release lithium ions at a potential nobler than 1.0 V (vs. Li / Li ⁺ ). Specific examples include lithium-containing metal composite oxide materials. These may be used individually by 1 type, and may be used together combining 2 or more types arbitrarily. In the present specification, when the reference of the potential is not clearly shown, the equilibrium potential of Li / Li ⁺ is used as a reference.

[1. Negative electrode active material]
Examples of the negative electrode active material capable of inserting and extracting lithium ions at a potential nobler than 1.0 V include lithium-containing metal composite oxide materials.
The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium. For example, tungsten oxide, molybdenum oxide, iron sulfide, titanium sulfide, lithium titanate, etc. Can be used. In view of high current density charge / discharge characteristics, a material containing titanium and lithium is preferable, more preferably a lithium-containing composite metal oxide material containing titanium, and still more preferably a composite oxide of lithium and titanium (hereinafter referred to as “lithium”). It may be abbreviated as “titanium composite oxide”. That is, it is particularly preferable to use a lithium titanium composite oxide having a spinel structure in a negative electrode active material for a non-aqueous electrolyte secondary battery because the output resistance is greatly reduced.

  Further, lithium or titanium of the lithium titanium composite oxide is selected from the group consisting of other metal elements such as Na, Mg, K, Al, Si, Cr, Fe, Co, Cu, Zn, Ga, Zr, and Nb. Those substituted with at least one element selected from the above are also preferred. Among these, those substituted with at least one element selected from the group consisting of Mg, Al, Si, Cu, Zn, Zr and Nb may be more preferable.

The metal oxide is a lithium titanium composite oxide represented by the general formula (A). In the general formula (A), 0.7 ≦ α ≦ 1.5, 1.5 ≦ β ≦ 2.3, It is preferable that 0 ≦ γ ≦ 1.6 because the structure upon doping and dedoping of lithium ions is stable.
Li _α Ti _β M _γ O ₄ (A)
(In the general formula (A), M represents at least one element selected from the group consisting of Na, Mg, K, Al, Si, Cr, Fe, Co, Cu, Zn, Ga, Zr and Nb. )
Among the compositions represented by the general formula (A),
(A) 1.2 ≦ α ≦ 1.4, 1.5 ≦ β ≦ 1.7, γ = 0
(B) 0.9 ≦ α ≦ 1.1, 1.9 ≦ β ≦ 2.1, γ = 0
(C) 0.7 ≦ α ≦ 0.9, 2.1 ≦ β ≦ 2.3, γ = 0
This structure is particularly preferable because of a good balance of battery performance.

Particularly preferred representative compositions of the above compounds are Li _4/3 Ti _5/3 O ₄ in (a), Li ₁ Ti ₂ O ₄ in (b), and Li _4/5 Ti _11/5 O in (c). ₄ . As for the structure of Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is preferable.

[2. Structure and manufacturing method of negative electrode]
Any known method can be used for producing the electrode as long as the effects of the present invention are not significantly impaired. For example, a binder (binder), a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. are added to the negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can be formed.

[2.1 Current collector]
As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper and aluminum are particularly preferable from the viewpoint of ease of processing and cost.

In addition, the shape of the current collector may be, for example, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, or the like when the current collector is a metal material. Among them, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable, and both can be used as a current collector.
The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. This is because if the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely if it is too thin, handling may be difficult.

[2.2 Thickness ratio between current collector and negative electrode active material layer]
The ratio of the thickness of the current collector to the negative electrode active material layer is not particularly limited, but the value of “(the thickness of the negative electrode active material layer on one side immediately before the nonaqueous electrolyte injection) / (thickness of the current collector)” However, 150 or less is preferable, 20 or less is more preferable, 10 or less is particularly preferable, 0.1 or more is preferable, 0.4 or more is more preferable, and 1 or more is particularly preferable. When the ratio of the thickness of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge / discharge. On the other hand, below the above range, the volume ratio of the current collector to the negative electrode active material increases, and the battery capacity may decrease.

[2.3 Binder]
The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolyte solution and the solvent used in manufacturing the electrode.
As a specific example,
Resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, polyimide, cellulose, nitrocellulose;
Rubber polymers such as SBR (styrene / butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile / butadiene rubber), ethylene / propylene rubber;
Styrene / butadiene / styrene block copolymer or hydrogenated product thereof;
Thermoplastic elastomeric polymers such as EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / styrene copolymer, styrene / isoprene / styrene block copolymer or hydrogenated product thereof;
Soft resinous polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer;
Fluoropolymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer;
And a polymer composition having ion conductivity of alkali metal ions (particularly lithium ions). These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, 15% by mass. The following is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is particularly preferable. When the ratio of the binder with respect to a negative electrode active material exceeds the said range, the binder ratio from which the amount of binders does not contribute to battery capacity may increase, and the fall of battery capacity may be caused. On the other hand, below the above range, the strength of the negative electrode may be reduced.

  In particular, when a rubbery polymer typified by SBR is contained as a main component, the ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0 .6% by mass or more is more preferable, and is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. When the main component contains a fluorine-based polymer typified by polyvinylidene fluoride, the ratio to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. It is preferably 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

[2.4 Slurry-forming solvent]
The solvent for forming the slurry is not particularly limited as long as it is a solvent capable of dissolving or dispersing the negative electrode active material, the binder, and the thickener and conductive material used as necessary. Alternatively, either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N- Examples include dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, and the like.

  In particular, when an aqueous solvent is used, it is preferable to add a dispersant and the like together with a thickener and make a slurry using a latex such as SBR. In addition, these solvents may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio.

[2.5 Thickener]
A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  Further, when using a thickener, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Moreover, it is 5 mass% or less normally, 3 mass% or less is preferable, and 2 mass% or less is more preferable. When the ratio of the thickener to the negative electrode active material is less than the above range, applicability may be significantly reduced. When the above range is exceeded, the proportion of the negative electrode active material in the negative electrode active material layer may decrease, and the battery capacity may decrease or the resistance between the negative electrode active materials may increase.

[2.6 Electrode density]
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases or non-aqueous system near the current collector / negative electrode active material interface. There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability of the electrolytic solution. On the other hand, if the amount is less than the above range, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume may decrease.

[2.7 Thickness of negative electrode plate]
The thickness of the negative electrode plate is designed according to the positive electrode plate to be used, and is not particularly limited. However, the thickness of the composite layer obtained by subtracting the thickness of the metal foil of the core is usually 15 μm or more, preferably 20 μm or more. More preferably, it is 30 μm or more, and usually 300 μm or less, preferably 280 μm or less, more preferably 250 μm or less.

[2.8 Surface coating of negative electrode plate]
Moreover, you may use that the substance of the composition different from a negative electrode plate adhered to the surface of the said negative electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

[III. Positive electrode]
[1. Cathode active material]
The positive electrode active material used for the positive electrode is described below.
[1.1 Composition]
The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable as the transition metal of the lithium transition metal composite oxide. Specific examples include lithium-cobalt composite oxides such as LiCoO ₂ and LiNiO ₂ . Lithium / nickel composite oxide, LiMnO ₂ , LiMn ₂ O ₄ , Li ₂ MnO _{4 and} other lithium / manganese composite oxides, and part of transition metal atoms that are the main components of these lithium transition metal composite oxides are Na , K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W, etc. Substituted ones are listed. As specific examples of the substituted ones, for example, LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.45 Co _0.10 Al _0.45 O ₂ , LiMn _1.8 Al _0.2 O ₄ , LiMn _1.5 Ni _0.5 O _{4 and the} like.

As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu and the like are preferable, and specific examples include, for example, LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ). ₃ , iron phosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are Al, Ti, V, Cr, Mn , Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si and the like substituted with other elements.

  In addition, it is preferable to include lithium phosphate in the positive electrode active material because continuous charge characteristics are improved. Although there is no restriction | limiting in the use of lithium phosphate, It is preferable to mix and use the said positive electrode active material and lithium phosphate. The lower limit of the amount of lithium phosphate used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.5% by mass with respect to the total of the positive electrode active material and lithium phosphate. %, And the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 5% by mass or less.

[1.2 Surface coating]
Further, a material in which a material having a composition different from that of the positive electrode active material is attached to the surface of the positive electrode active material may be used. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

  These surface adhering substances are, for example, dissolved or suspended in a solvent and impregnated and added to the positive electrode active material, and then dried. The surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material. Then, it can be made to adhere to the surface of this positive electrode active material by the method of making it react by heating etc., the method of adding to a positive electrode active material precursor, and baking simultaneously. In addition, when making carbon adhere, the method of making carbonaceous adhere mechanically later in the form of activated carbon etc. can also be used, for example.

The amount of the surface adhering substance is, in terms of mass with respect to the positive electrode active material, preferably 0.1 ppm or more, more preferably 1 ppm or more, further preferably 10 ppm or more, and the upper limit, preferably 20% or less, more preferably, as the lower limit. Is used at 10% or less, more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material, and can improve the battery life. Moreover, when too much, resistance may increase in order to inhibit the entrance / exit of lithium ion.
In the present invention, a “positive electrode active material” includes a material having a composition different from that of the positive electrode active material.

[1.3 Shape]
Examples of the shape of the particles of the positive electrode active material include a lump shape, a polyhedron shape, a sphere shape, an oval sphere shape, a plate shape, a needle shape, and a column shape as conventionally used. Moreover, primary particles may aggregate to form secondary particles.

[1.4 Tap density]
The tap density of the positive electrode active material is preferably 0.5 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, and further preferably 1.0 g / cm ³ or more. If the tap density of the positive electrode active material is lower than the lower limit, the amount of the required dispersion medium increases when the positive electrode active material layer is formed, and the required amount of the conductive material and the binder increases, so The filling rate of the active material is restricted, and the battery capacity may be restricted.

By using a complex oxide powder having a high tap density, a high-density positive electrode active material layer can be formed. In general, the tap density is preferably as large as possible, and there is no particular upper limit, but if it is too large, diffusion of lithium ions using the electrolytic solution in the positive electrode active material layer as a medium is rate-limiting, and load characteristics may be easily reduced. The upper limit is preferably 4.0 g / cm ³ or less, more preferably 3.7 g / cm ³ or less, and still more preferably 3.5 g / cm ³ or less.
In the present invention, the tap density is defined as the powder packing density (tap density) g / mL when 5 to 10 g of the positive electrode active material powder is put in a 10 ml glass measuring cylinder and tapped 200 times with a stroke of about 20 mm. Ask.

[1.5 median diameter d ₅₀ ]
The median diameter d ₅₀ of the positive electrode active material particles (secondary particle diameter when primary particles are aggregated to form secondary particles) is preferably 0.3 μm or more, more preferably 0.5 μm or more, and further The upper limit is preferably 30 μm or less, more preferably 27 μm or less, still more preferably 25 μm or less, and most preferably 22 μm or less. If the lower limit is not reached, a high tap density product may not be obtained. If the upper limit is exceeded, it takes time to diffuse lithium in the particles. When a substance, a conductive material, a binder, or the like is slurried with a solvent and applied in a thin film, problems such as streaking may occur. Here, different median size d ₅₀ by mixing 2 or more kinds of positive electrode active material with, it is possible to further improve the filling property at the time of the positive electrode creation.
In the present invention, the median diameter d ₅₀ is measured by a known laser diffraction / scattering particle size distribution measuring apparatus. When LA-920 manufactured by HORIBA is used as a particle size distribution meter, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as a dispersion medium for measurement, and a measurement refractive index of 1.24 is set after ultrasonic dispersion for 5 minutes. Measured.

[1.6 Average primary particle size]
When primary particles are aggregated to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.8 μm. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less, and most preferably 2 μm or less. If the above upper limit is exceeded, it is difficult to form spherical secondary particles, which adversely affects the powder filling property, or the specific surface area is greatly reduced, so that there is a high possibility that battery performance such as output characteristics will deteriorate. is there. On the other hand, when the value falls below the lower limit, there is a case where problems such as inferior reversibility of charge / discharge are usually caused because crystals are not developed.
In the present invention, the average primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000 times, the longest value of the intercept by the left and right boundary lines of the primary particles with respect to the horizontal straight line is obtained for any 50 primary particles and obtained by taking the average. It is done.

[1.7 BET specific surface area]
The BET specific surface area of the positive electrode active material is preferably 0.1 m ² / g or more, more preferably 0.2 m ² / g or more, still more preferably 0.3 m ² / g or more, and the upper limit is 50 m ² / g or less. , Preferably 40 m ² / g or less, more preferably 30 m ² / g or less. If the BET specific surface area is smaller than this range, the battery performance tends to be lowered. If the BET specific surface area is larger, the tap density is difficult to increase, and a problem may occur in applicability when forming the positive electrode active material layer.
In the present invention, the BET specific surface area is determined by using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken), preliminarily drying the sample for 30 minutes at 150 ° C. under a nitrogen flow, and then atmospheric pressure. This is defined as a value measured by a nitrogen adsorption BET one-point method using a gas flow method, using a nitrogen-helium mixed gas accurately adjusted so that the value of the relative pressure of nitrogen to 0.3 is 0.3.

[1.8 Method for producing positive electrode active material]
As a manufacturing method of the positive electrode active material, a general method is used as a manufacturing method of the inorganic compound. In particular, various methods are conceivable for producing a spherical or elliptical active material. For example, a transition metal raw material is dissolved or ground and dispersed in a solvent such as water, and the pH is adjusted while stirring. And a spherical precursor is prepared and recovered, dried as necessary, and then added with a Li source such as LiOH, Li ₂ CO ₃ , LiNO _{3 and the} like, and then fired at a high temperature to obtain an active material. .

For the production of the positive electrode, the positive electrode active material may be used alone, or one or more of different compositions may be used in any combination or ratio. A preferred combination in this case is a combination of LiCoO ₂ and LiMn ₂ O ₄ such as LiNi _0.33 Co _0.33 Mn _0.33 O ₂ or a part of Mn substituted with another transition metal or the like. Or a combination with LiCoO ₂ or a part of this Co substituted with another transition metal or the like.

[2. Structure and manufacturing method of positive electrode]
The structure of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. Manufacture of the positive electrode using a positive electrode active material can be performed by a conventional method. That is, a positive electrode active material and a binder, and if necessary, a conductive material and a thickener mixed in a dry form into a sheet form are pressure-bonded to the positive electrode current collector, or these materials are liquid media A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by applying it to a positive electrode current collector and drying it as a slurry by dissolving or dispersing in a slurry.

  The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. Moreover, an upper limit becomes like this. Preferably it is 99 mass% or less, More preferably, it is 98 mass% or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electric capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1.5 g / cm ³ or more as a lower limit, more preferably 2 g / cm ³ , still more preferably 2.2 g / cm ³ or more, and the upper limit is preferably 5 g / cm 3. ^{It is 3} or less, more preferably 4.5 g / cm ³ or less, and further preferably 4 g / cm ³ or less. If it exceeds this range, the permeability of the electrolyte solution to the vicinity of the current collector / active material interface decreases, and the charge / discharge characteristics particularly at a high current density decrease, and a high output may not be obtained. On the other hand, if the value is below the above range, the conductivity between the active materials is lowered, the battery resistance is increased, and a high output may not be obtained.

[2.1 Conductive material]
A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The conductive material is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more in the positive electrode active material layer, and the upper limit is usually 50% by mass or less, preferably It is used so as to contain 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

[2.2 Binder]
The binder (binder) used for manufacturing the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material can be used as long as it is dissolved or dispersed in a liquid medium used during electrode manufacturing. As a specific example,
Resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose;
Rubbery polymers such as SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber;
Styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / ethylene copolymer, styrene / isoprene / styrene block copolymer or Thermoplastic elastomeric polymers such as hydrogenated products;
Soft resinous polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer;
Fluoropolymers such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer;
And a polymer composition having ion conductivity of alkali metal ions (particularly lithium ions). In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, and the upper limit is usually 80% by mass or less, preferably Is 60% by mass or less, more preferably 40% by mass or less, and most preferably 10% by mass or less. When the ratio of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. On the other hand, if it is too high, battery capacity and conductivity may be reduced.

[2.3 Slurry-forming solvent]
As the solvent for forming the slurry, the positive electrode active material, the conductive material, the binder, and a solvent capable of dissolving or dispersing the thickener used as necessary may be used. There is no restriction, and either an aqueous solvent or an organic solvent may be used. Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of the organic medium include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone. Esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N, N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide and tetrahydrofuran (THF); N-methylpyrrolidone (NMP) Amides such as dimethylformamide and dimethylacetamide; and aprotic polar solvents such as hexamethylphosphalamide and dimethylsulfoxide.

  In particular, when an aqueous medium is used, it is preferable to make a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  When a thickener is further added, the ratio of the thickener to the active material is 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more. The upper limit is 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. Below this range, applicability may be significantly reduced. When the above range is exceeded, the proportion of the active material in the positive electrode active material layer may decrease, and the battery capacity may decrease or the resistance between the positive electrode active materials may increase.

[2.4 Current collector]
The material of the positive electrode current collector is not particularly limited, and a known material can be arbitrarily used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbon materials such as carbon cloth and carbon paper. Of these, metal materials, particularly aluminum, are preferred.

  Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, and foam metal in the case of a metal material. A thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape. Although the thickness of the thin film is arbitrary, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. If the thin film is thinner than this range, the strength required for the current collector may be insufficient. Conversely, if the thin film is thicker than this range, the handleability may be impaired.

Moreover, it is also preferable from the viewpoint of reducing the electronic contact resistance between the current collector and the positive electrode active material layer that a conductive additive is applied to the surface of the current collector. Examples of the conductive assistant include noble metals such as carbon, gold, platinum, and silver.
The ratio of the thickness of the current collector to the positive electrode active material layer is not particularly limited, but the value of (thickness of the positive electrode active material layer on one side immediately before electrolyte injection) / (thickness of the current collector) is 20 The lower limit is preferably 15 or less, most preferably 10 or less, and the lower limit is preferably 0.5 or more, more preferably 0.8 or more, and most preferably 1 or more. Above this range, the current collector may generate heat due to Joule heat during high current density charge / discharge. Below this range, the volume ratio of the current collector to the positive electrode active material increases and the battery capacity may decrease.

[2.5 Electrode area]
When using the non-aqueous electrolyte of the present invention, it is preferable that the area of the positive electrode active material layer is larger than the outer surface area of the battery outer case from the viewpoint of increasing the stability at high output and high temperature. Specifically, the sum of the electrode areas of the positive electrode with respect to the surface area of the exterior of the secondary battery is preferably 15 times or more, and more preferably 40 times or more.

  The outer surface area of the outer case is the total area obtained by calculation from the vertical, horizontal, and thickness dimensions of the case part filled with the power generation element excluding the protruding part of the terminal in the case of a bottomed square shape. . In the case of a bottomed cylindrical shape, the geometric surface area approximates the case portion filled with the power generation element excluding the protruding portion of the terminal as a cylinder. The total electrode area of the positive electrode is the geometric surface area of the positive electrode mixture layer facing the mixture layer containing the negative electrode active material, and in the structure in which the positive electrode mixture layer is formed on both sides via the current collector foil. , The sum of the areas where each surface is calculated separately.

[2.6 Thickness of positive electrode plate]
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the composite layer obtained by subtracting the metal foil thickness of the core material is preferably as a lower limit with respect to one side of the current collector. Is 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

[2.7 Surface coating of positive electrode plate]
Moreover, you may use that the substance of the composition different from a positive electrode plate adhered to the surface of the said positive electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

[IV. Separator]
In the non-aqueous electrolyte secondary battery of the present invention, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, in the present invention, a polyolefin resin, a resin in which an inorganic substance is dispersed, other resins, glass fibers, etc., which are formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention may be used as a constituent component. I can do it. As the shape, it is preferable to use a porous sheet excellent in liquid retention or a non-woven fabric.

[1. Separator type]
The separator used in the present invention may have a polyolefin resin as a part of the constituent components. Specific examples of the polyolefin resin include a polyethylene resin, a polypropylene resin, and 1-polymethylpentene.
Examples of polyethylene resins include low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ethylene-based copolymers, that is, ethylene and propylene, Α-olefins having 3 to 10 carbon atoms such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene; vinyl esters such as vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate, Copolymer or multi-component copolymer with one or more comonomers selected from unsaturated carboxylic acid esters such as methyl methacrylate and ethyl methacrylate; or unsaturated compounds such as conjugated dienes and non-conjugated dienes; Examples thereof include a polymer or a mixed composition thereof. The ethylene unit content of the ethylene polymer is usually more than 50% by mass.

Among these polyethylene resins, at least one polyethylene resin selected from low density polyethylene, linear low density polyethylene, and high density polyethylene is preferable, and high density polyethylene is most preferable.
Moreover, there is no restriction | limiting in particular in the polymerization catalyst of a polyethylene-type resin, Any things, such as a Ziegler type catalyst, a Phillips type catalyst, and a Kaminsky type catalyst, may be sufficient. As a polymerization method of the polyethylene resin, there are a one-stage polymerization, a two-stage polymerization, or a multistage polymerization more than that, and any method of the polyethylene resin can be used.

  The melt flow rate (MFR) of the polyethylene resin is not particularly limited, but usually the MFR is preferably 0.03 to 15 g / 10 min, and preferably 0.3 to 10 g / 10 min. preferable. If the MFR is in the above range, the back pressure of the extruder does not become too high during the molding process and the productivity is excellent. In addition, MFR in this invention refers to the measured value on condition of temperature 190 degreeC and load 2.16kg based on JISK7210 (1999).

The production method of the polyethylene resin is not particularly limited, and is a known polymerization method using a known olefin polymerization catalyst, for example, a multisite catalyst represented by a Ziegler-Natta type catalyst or a metallocene catalyst. A polymerization method using a single site catalyst may be mentioned.
Next, an example of a polypropylene resin will be described. As the polypropylene resin in the present invention, homopolypropylene (propylene homopolymer), or propylene and ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-nonene. Examples thereof include random copolymers or block copolymers with α-olefins such as decene. Among these, when used for a battery separator, homopolypropylene is more preferably used from the viewpoint of mechanical strength.

  The polypropylene resin preferably has an isotactic pentad fraction exhibiting stereoregularity of 80 to 99%, more preferably 83 to 98%, and still more preferably 85 to 97%. use. If the isotactic pentad fraction is too low, the mechanical strength of the battery separator may decrease. On the other hand, the upper limit of the isotactic pentad fraction is defined by the upper limit that can be obtained industrially at present, but this is not the case when a more regular resin is developed in the industrial level in the future. is not.

  The isotactic pentad fraction is a three-dimensional structure in which five methyl groups that are side chains are located in the same direction with respect to the main chain of carbon-carbon bonds composed of arbitrary five consecutive propylene units. Or the ratio is meant. Signal assignment of the methyl group region is as follows. Zambellietatal. (Macromol. 8, 687 (1975)).

  Moreover, it is preferable that Mw / Mn which is a parameter which shows molecular weight distribution of a polypropylene resin is 1.5-10.0. More preferably, 2.0 to 8.0, and still more preferably 2.0 to 6.0 is used. This means that the smaller the Mw / Mn, the narrower the molecular weight distribution. However, if the Mw / Mn is less than 1.5, the extrudability may be reduced and it may be difficult to produce industrially. is there. On the other hand, when Mw / Mn exceeds 10.0, the low molecular weight component increases, and the mechanical strength of the obtained battery separator tends to decrease. Mw / Mn is obtained by GPC (gel permeation chromatography) method.

Further, the melt flow rate (MFR) of the polypropylene resin is not particularly limited, but usually the MFR is preferably 0.1 to 15 g / 10 minutes, and preferably 0.5 to 10 g / 10 minutes. It is more preferable. When the MFR is less than 0.1 g / 10 minutes, the melt viscosity of the resin during the molding process is high, and the productivity is lowered. On the other hand, when it exceeds 15 g / 10 minutes, practical problems such as insufficient strength of the obtained battery separator tend to occur. MFR is measured under the conditions of a temperature of 230 ° C. and a load of 2.16 kg in accordance with JIS K7210 (1999).

  The separator used in the present invention may be a resin separator in which an inorganic substance is dispersed. The inorganic substance is not particularly limited as long as it does not inhibit the battery reaction. For example, titanium oxide, silicon oxide, barium oxide, aluminum oxide, magnesium oxide, potassium oxide, silicon oxide, potassium titanate, magnesium potassium titanate, Examples thereof include barium titanate, tin oxide, zinc oxide, tantalum, kaolinite, montmorillonite, mica, calcium carbonate, zirconia, and lithium titanate phosphate. The metal constituting these compounds is at least one selected from the group consisting of other metal elements such as Na, Mg, K, Al, Si, Cr, Fe, Co, Cu, Zn, Ga, Zr and Nb. It may be substituted with an element. These inorganic substances may be used alone or in combination of two or more. Also. As long as it does not inhibit the battery reaction, it is possible to subject the inorganic material to a surface treatment or the like by a known method.

There is no restriction | limiting in particular as a shape of an inorganic substance, A spherical shape, plate shape, on a fiber, other amorphous shapes, or a mixture thereof may be sufficient.
As resin used for dispersion,
Resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose;
Rubbery polymers such as SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber;
Styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / ethylene copolymer, styrene / isoprene / styrene block copolymer or Thermoplastic elastomeric polymers such as hydrogenated products;
Soft resinous polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer;
Fluoropolymers such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer;
And a polymer composition having ion conductivity of alkali metal ions (particularly lithium ions). In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  As materials for other resins and glass fiber separators, for example, aromatic polyamide, polytetrafluoroethylene, polyethersulfone, glass filter, and the like can be used in combination with the polyolefin resin. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

[2. Separator shape]
The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

Furthermore, when a porous material such as a porous sheet or nonwoven fabric is used as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, and 45%
The above is more preferable, and it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used.
In addition to the above-mentioned independent thin film shape, a separator formed by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, a porous layer may be formed by using alumina particles having a 90% particle size (average particle size d90) of less than 1 μm on both surfaces of the positive electrode and using a fluororesin as a binder.

[V. Battery design]
[1. Electrode group]
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed through the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape through the separator. Either is acceptable. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as “electrode group occupation ratio”) is usually 40% or more, preferably 50% or more, and usually 90% or less, 80% The following is preferred.

  When the electrode group occupancy is below the above range, the battery capacity decreases. In addition, if the above range is exceeded, there are few void spaces, the expansion of the member due to the high temperature of the battery and the increase of the internal pressure due to the increase of the vapor pressure of the liquid component of the electrolyte. In some cases, various characteristics are deteriorated, and further, a gas release valve for releasing the internal pressure to the outside is operated.

[2. Current collection structure]
The current collecting structure is not particularly limited, but in order to more effectively realize the high current density charge / discharge characteristics by the non-aqueous electrolyte solution of the present invention, a structure that reduces the resistance of the wiring part and the joint part is used. It is preferable. Thus, when internal resistance is reduced, the effect of using the non-aqueous electrolyte solution of this invention is exhibited especially favorable.

  In the case where the electrode group has the above laminated structure, a structure formed by bundling the metal core portions of the electrode layers and welding them to the terminals is preferably used. When the area of one electrode increases, the internal resistance increases. Therefore, it is also preferable to provide a plurality of terminals in the electrode to reduce the resistance. When the electrode group has the winding structure described above, the internal resistance can be lowered by providing a plurality of lead structures for the positive electrode and the negative electrode, respectively, and bundling the terminals.

[3. Exterior case]
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum, an aluminum alloy, a metal such as a magnesium alloy, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

In an exterior case using metals, the metal is welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed sealed structure, or a caulking structure using the above metals via a resin gasket. Things. Examples of the outer case using the laminate film include a case where a resin-sealed structure is formed by heat-sealing resin layers.
In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when the resin layer is heat-sealed through a current collecting terminal to form a sealed structure, since the metal and the resin are joined, a modification having a polar group or a polar group introduced as the intervening resin Resins are preferably used.

[4. Protective element]
Protection elements such as PTC (Positive Temperature Coefficient), thermal fuse, thermistor, which increases resistance when abnormal heat is generated or excessive current flows, shuts off current flowing through the circuit due to sudden increase in battery internal pressure or internal temperature during abnormal heat generation A valve (current cutoff valve) or the like can be used. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable that the protective element is designed so as not to cause abnormal heat generation or thermal runaway even without the protective element.

[5. Exterior body]
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.
The shape of the exterior body is also arbitrary, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
In addition, each evaluation method of the lithium secondary battery obtained by the following Example and the comparative example is shown below.

[Run-in operation]
The obtained lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state where the lithium secondary battery was sandwiched between glass plates in order to enhance the adhesion between the electrodes. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 2C represents a current value that is twice that, and 0.2C represents a current value that is 1/5 of the current value.

[Preservation test]
The lithium secondary battery after the running-in operation was charged to 2.7 V and stored at 60 ° C. for 1 week. The volume was measured before and after storage using the Archimedes method, and the value of (volume after storage-volume before storage) was calculated as the amount of gas generated.
After measuring the amount of gas generated, it was discharged to 1.5 V at a constant current of 0.2 C at 25 ° C.

Next, after charging to 2.7 V at a constant current of 0.2 C at 25 ° C., charging was performed until the current value reached 0.05 C at a constant voltage of 2.7 V, and 1 at a constant current of 0.2 C. The battery was discharged to 5 V, the 0.2 C discharge capacity after the high temperature storage test was measured, and the recovery capacity was obtained.
[Discharge 10C rate test]
The lithium secondary battery after the running-in operation was charged to 2.7 V and discharged at 10 C, and the value obtained at that time was defined as 10 C discharge capacity (mAh). The manufactured lithium secondary battery was standardized so that the discharge capacity at 0.2 C was about 34 mAh.

<Test Example A>
(Example A-1)
[Manufacture of negative electrode]
A lithium titanium composite oxide was used as the negative electrode active material, and a negative electrode composed of lithium titanium composite oxide: conductive auxiliary agent: binder 91: 4: 5 (mass ratio) was produced by the method described in the above specification. The potential at which the lithium titanium composite oxide used occludes and releases lithium ions is 1.2 to 2.0V. The negative electrodes used in Examples A-1 to A-4 and Comparative Examples A-1 to A-3 were all the same.

[Production of positive electrode]
92% by mass of lithium cobalt nickel manganese oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride ( PVdF) 3% by mass was mixed with a disperser in an N-methylpyrrolidone solvent to form a slurry. This was uniformly applied to both sides of the aluminum foil, dried, and then pressed to obtain a positive electrode. The positive electrodes used in Examples A-1 to A-7 and Comparative Examples A-1 to A-4 were all the same.

[Production of non-aqueous electrolyte]
In a dry argon atmosphere, LiPF ₆ dried in a solvent, which is a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio 3: 7), was dissolved to a ratio of 1 mol / L, and non-aqueous electrolysis was performed. Hexamethylene diisocyanate (HMDI) was mixed as an additive so that the content in the liquid was 5% by mass to obtain an electrolytic solution.

[Manufacture of non-aqueous electrolyte secondary batteries]
A battery element was fabricated by laminating a negative electrode, a separator, and a positive electrode. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum were coated with a resin layer while projecting positive and negative terminals, and the electrolyte prepared above was poured into the bag and vacuum sealed. Then, a sheet-like battery was produced. As the evaluation of gas generation amount and discharge characteristics of the obtained non-aqueous electrolyte secondary battery, the above-described storage test and discharge 10C rate test were performed, respectively. The evaluation results are shown in Table 1.

(Example A-2)
In the electrolytic solution of Example A-1, a non-aqueous electrolytic solution was prepared in the same manner as in Example A-1, except that 0.5% by mass of lithium difluorophosphate (MP1) was added in addition to 5% by mass of HMDI. Then, a sheet-like battery was produced. The amount of gas generation and discharge characteristics of the obtained non-aqueous electrolyte secondary battery were evaluated. The evaluation results are shown in Table 1.

(Example A-3)
In the electrolyte solution of Example A-1, a non-aqueous electrolyte solution was prepared in the same manner as in Example A-1, except that 5% by mass of HMDI and 0.5% by mass of FSO ₃ Li were added. A battery was produced. The amount of gas generation and discharge characteristics of the obtained non-aqueous electrolyte secondary battery were evaluated. The evaluation results are shown in Table 1.

(Example A-4)
A non-aqueous electrolyte solution was prepared in the same manner as in Example A-1, except that the content of HMDI was 15% by mass in the electrolyte solution of Example A-1, and a sheet-like battery was produced. The amount of gas generation and discharge characteristics of the obtained non-aqueous electrolyte secondary battery were evaluated. The evaluation results are shown in Table 1.
(Comparative Example A-1)
A non-aqueous electrolyte was prepared in the same manner as in Example A-1, except that no additive was mixed in the electrolyte of Example A-1, and a sheet-like battery was produced. The amount of gas generation and discharge characteristics of the obtained non-aqueous electrolyte secondary battery were evaluated. The evaluation results are shown in Table 1.

(Comparative Example A-2)
In the electrolyte solution of Example A-1, Example A was used except that a mixture of EC and DEC (volume ratio 4: 6) was used instead of the mixture of EC and DEC (volume ratio 3: 7). A non-aqueous electrolyte solution was prepared in the same manner as -1, and a sheet-like battery was produced. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 1.

(Comparative Example A-3)
In the electrolyte solution of Example A-1, Example A was used except that the mixture of EC and DEC (volume ratio 5: 5) was used instead of the mixture of EC and DEC (volume ratio 3: 7). A non-aqueous electrolyte solution was prepared in the same manner as -1, and a sheet-like battery was produced. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 1.

<Test Example B>
(Comparative Example B-1)
In Example A-1, the negative electrode active material was replaced with lithium titanium composite oxide, 98 parts by mass of graphite powder and 2 parts by mass of PVdF were mixed, and water was added to form a slurry.
A negative electrode was produced in the same manner as in Example A-1, except that a negative electrode prepared by applying and drying on one side of a current collector made of copper was used, and a sheet-like battery was produced together with the positive electrode and a non-aqueous electrolyte. . Evaluation of gas generation amount and discharge characteristics of the obtained non-aqueous electrolyte secondary battery was not possible because the resistance was remarkably increased due to the inclusion of HMDI and charging was insufficient.
The graphite powder used as the negative electrode active material occludes and releases lithium ions at 0.005 to 0.5 V.

<Test Example C>
(Example C-1)
[Manufacture of negative electrode]
A lithium titanium composite oxide was used as the negative electrode active material, and a negative electrode composed of lithium titanium composite oxide: conductive auxiliary agent: binder 91: 4: 5 (mass ratio) was produced by the method described in the above specification. The potential at which the lithium titanium composite oxide used occludes and releases lithium ions is 1.2 to 2.0V. The negative electrodes used in Examples C-1 to C-4 and Comparative Examples C-1 to C-3 were all the same.

[Production of positive electrode]
85% by mass of lithium nickel cobalt-containing oxide (Li (Ni _0.8 Co _0.15 Al _0.05 ) O ₂ ) as a positive electrode active material, 7% by mass of acetylene black as a conductive material, and polyfluoride as a binder. 8% by mass of vinylidene chloride (PVdF) was mixed with a disperser in an N-methylpyrrolidone solvent to form a slurry. This was uniformly applied to both sides of the aluminum foil, dried, and then pressed to obtain a positive electrode. The negative electrodes used in Examples C-1 to C-4 and Comparative Examples C-1 to C-3 were all the same.

[Production of non-aqueous electrolyte]
In a dry argon atmosphere, LiPF ₆ dried in a solvent, which is a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio 3: 7), was dissolved to a ratio of 1 mol / L, and non-aqueous electrolysis was performed. HMDI was mixed as an additive so that the content in the liquid was 0.3% by mass to obtain an electrolytic solution.

[Manufacture of non-aqueous electrolyte secondary batteries]
A battery element was fabricated by laminating a negative electrode, a separator, and a positive electrode. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum were coated with a resin layer while projecting positive and negative terminals, and the electrolyte prepared above was poured into the bag and vacuum sealed. Then, a sheet-like battery was produced. The storage test mentioned above was done as evaluation of the gas generation amount of the obtained non-aqueous electrolyte secondary battery. The evaluation results are shown in Table 2.

(Example C-2)
A non-aqueous electrolyte solution was prepared in the same manner as in Example C-1, except that the content of HMDI was 0.6% by mass in the electrolyte solution of Example C-1, and a sheet-like battery was produced. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 2.
(Example C-3)
A non-aqueous electrolyte solution was prepared in the same manner as in Example C-1, except that the content of HMDI was changed to 5% by mass in the electrolyte solution of Example C-1, and a sheet-like battery was produced. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 2.

(Example C-4)
In the electrolyte solution of Example C-3, the additive was replaced with HMDI, except that 5% by mass of 1,3-bis (isocyanatomethyl) cyclohexane (BIMCH) was used. A water-based electrolyte was prepared to produce a sheet battery. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 2.

(Comparative Example C-1)
In the electrolytic solution of Example C-1, a non-aqueous electrolytic solution was prepared in the same manner as in Example C-1, except that no additive was mixed. A sheet-like battery was produced. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 2.

(Comparative Example C-2)
In the electrolytic solution of Example C-1, a non-aqueous electrolytic solution was prepared in the same manner as in Example C-1, except that 0.5% by mass of vinylene carbonate (VC) was added instead of HMDI. A sheet battery was produced. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 2.

(Comparative Example C-3)
In the electrolyte solution of Example C-1, the non-aqueous electrolyte solution was the same as Example C-1, except that 0.5% by mass of 1,3-propane sultone (PS) was added instead of HMDI. Was prepared to produce a sheet-like battery. The gas generation amount of the obtained non-aqueous electrolyte secondary battery was evaluated. The evaluation results are shown in Table 2.

  As described above, the non-aqueous electrolyte secondary battery using the non-aqueous electrolyte of the present invention can suppress gas generation during high-temperature storage and improve battery characteristics. The non-aqueous electrolyte secondary battery using the non-aqueous electrolyte of the present invention has a high capacity retention rate and excellent input / output performance even after endurance tests such as a high-temperature storage test and a cycle test. It is considered that the output characteristics are also excellent.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on June 15, 2012 (Japanese Patent Application No. 2012-136081), the contents of which are incorporated herein by reference.

  The non-aqueous electrolyte secondary battery of the present invention can be used for various known applications. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, Load Examples include leveling power sources and natural energy storage power sources.

Claims (5)

A non-aqueous electrolyte solution comprising a lithium salt and a non-aqueous solvent for dissolving the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte secondary battery comprising a positive electrode,
The negative electrode includes a negative electrode active material that occludes and releases lithium ions at a potential nobler than 1.0 V (vs. Li ^/ Li ⁺ );
The non-aqueous electrolyte secondary battery, wherein the non-aqueous solvent contains 30% by volume or less of ethylene carbonate with respect to the non-aqueous solvent, and the non-aqueous electrolyte further contains a compound having an isocyanate group. The non-aqueous electrolyte secondary battery according to claim 1, wherein the compound having an isocyanate group is a compound represented by the following general formula (1).

(Wherein, A represents a hydrogen atom, a halogen atom, a vinyl group, an isocyanate group, or a _C 1 ~
C represents a _{2 0} aliphatic hydrocarbon group (which may have a hetero atom) or a C ₆ -C _{2 0} aromatic hydrocarbon group (which may have a hetero atom). B is CO 2, S 2 O
₂ or a C ₁ to C ₂₀ aliphatic hydrocarbon group (which may have a hetero atom), or a C _{6 to} C ₂₀ aromatic hydrocarbon group (which may have a hetero atom) Represents good). ) The non-aqueous electrolyte secondary battery according to claim 2, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the above general formula (2), X represents a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with fluorine)   4. The non-aqueous system according to claim 1, wherein the content of the compound having an isocyanate group is 0.01% by mass or more and 10% by mass or less with respect to the entire non-aqueous electrolyte solution. Electrolyte secondary battery.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode active material is a lithium titanium composite oxide.