JP2018063942A - Nonaqueous electrolyte and power storage device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy device which is allowed to have superior battery characteristics over a long-term usage period.SOLUTION: A nonaqueous electrolyte of the present invention is a nonaqueous electrolyte with an electrolyte dissolved in a nonaqueous solvent. The nonaqueous electrolyte comprises a cyclic carbonate, and a compound represented by the general formula (1) below. (In the formula (1), Rto Reach represent an organic group with 1-20C, which may be identical to each other or not, and may have a substituent group, provided that at least one of Rto Rhas a carbon-carbon unsaturated bond or a cyano group.)SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous electrolyte and an electricity storage device using the same.

Lithium secondary batteries, electric double-layer capacitors, and so on in a wide range of applications such as mobile phone power supplies for mobile phones and stationary large power supplies, from so-called consumer power supplies such as mobile phones and laptop computers
An electricity storage device using a non-aqueous electrolyte such as a lithium ion capacitor has been put into practical use.
However, the demand for higher performance of power storage devices in recent years is increasing.
For example, in lithium non-aqueous electrolyte secondary batteries, cyclic carbonates such as ethylene carbonate and propylene carbonate, chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, γ-butyrolactone, γ-valerolactone, etc. A non-aqueous electrolyte containing a non-aqueous solvent of a cyclic carboxylic acid ester, a chain carboxylic acid ester such as methyl acetate, ethyl acetate, or methyl propionate and a solute (electrolyte) such as LiPF ₆ or LiBF ₄ is used. It is done.

In such an electricity storage device using a non-aqueous electrolyte solution such as a non-aqueous electrolyte secondary battery, the reactivity varies depending on the composition of the non-aqueous electrolyte solution. Become. Various studies on non-aqueous solvents and electrolytes in non-aqueous electrolytes to improve battery characteristics such as load characteristics, cycle characteristics, and storage characteristics of power storage devices, and to improve battery safety during overcharge Has been made.

For example, Patent Document 1 discloses a technique for suppressing self-discharge during high-temperature storage by using an electrolyte containing tricarbimide in a non-aqueous electrolyte battery using lithium-containing cobalt dioxide as a positive electrode active material. Has been.
Patent Document 2 discloses a technique for obtaining a battery excellent in load characteristics even after high-temperature storage by suppressing reductive decomposition of a solvent by using a nonaqueous electrolytic solution containing an isocyanuric acid derivative.

Patent Document 3 discloses a battery represented by the flame retardancy of an electrolytic solution by using a non-aqueous electrolytic solution containing a phosphite ester and a compound having two or more polymerizable functional groups in the molecule at the same time. A technology that achieves both safety and battery cycle characteristics is disclosed.
Non-Patent Document 1 discloses that a number of molecules of ethylene carbonate are coordinated to lithium ions using a computational scientific method for supramolecules composed of ethylene carbonate, which is a kind of cyclic carbonate, and lithium ions. It is described that it was analyzed whether it was mechanically stable, and the result that Li ⁺ (EC) _{4 in} which four molecules of ethylene carbonate coordinate with one lithium ion was thermodynamically stable was derived.

JP-A-7-192757 JP 2000-348705 A JP 2010-282906 A

Journal of American Chemical Society, 2001, 123 (47), p11708.

However, in recent years, there has been an increasing demand for improving the characteristics of power storage devices, and there is a need to have various performances at a high level. Has not yet been achieved. In particular, there is a problem that it is difficult to simultaneously satisfy the characteristics such as reducing the resistance and shortening the charging time after use and improving the large current characteristics.

The present invention has been made in view of the above-described problems. That is, an object of the present invention is to provide an electricity storage device that is excellent in overall characteristics and has little deterioration.

As a result of intensive studies in order to solve the above problems, the present inventors have found that the above problems can be solved by including a specific compound described later in the non-aqueous electrolyte solution, and the present invention has been completed. It was.
That is, the gist of the present invention is as follows.
[1] A nonaqueous electrolytic solution in which an electrolyte is dissolved in a nonaqueous solvent, which contains a cyclic carbonate and a compound represented by the following general formula (1).

(In the formula ^(1), R 1 ~R ^3, which may be the being the same or different, is an organic group having 1 to 20 carbon atoms that may have a substituent. However, R ¹ at least one of to R ³ is a carbon - carbon unsaturated bond or a cyano group).

[2] The non-aqueous electrolyte solution according to [1], wherein the content of the cyclic carbonate is less than 4 times the content of the electrolyte.
[3] In the general formula (1), R ^{1 to} R ³ may be the same as or different from each other;
The nonaqueous electrolytic solution according to [1] or [2], which is an organic group having 1 to 10 carbon atoms which may have a substituent.

[4] The non-aqueous system according to any one of [1] to [3], wherein in the general formula (1), at least one of R ^{1 to} R ³ is an organic group having a carbon-carbon unsaturated bond. Electrolytic solution.
[5] In any one of [1] to [4], in the general formula (1), the organic group having a carbon-carbon unsaturated bond is a group selected from the group consisting of an allyl group and a methallyl group. The non-aqueous electrolyte described.

[6] The compound having the structure represented by the general formula (1) is added to the total amount of the non-aqueous electrolyte solution.
The nonaqueous electrolytic solution according to any one of [1] to [5], which is contained in an amount of 0.01% by mass or more and 10.0% by mass or less.
[7] The non-aqueous system according to any one of [1] to [6], further comprising at least one compound selected from the group consisting of difluorophosphate, fluorosulfate, and dicarboxylic acid complex salts. Electrolytic solution.

[8] The nonaqueous electrolytic solution according to any one of [1] to [7], wherein the electrolyte is LiPF ₆ .
[9] The nonaqueous electrolytic solution according to any one of [1] to [8], further containing vinylene carbonate.
[10] The nonaqueous electrolytic solution according to any one of [1] to [9], further containing a lithium fluorosulfate salt.

[11] An electricity storage device comprising a plurality of electrodes capable of inserting and extracting metal ions and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is any one of [1] to [10] An electricity storage device that is a non-aqueous electrolyte.
[12] The plurality of electrodes capable of occluding and releasing metal ions are a positive electrode capable of occluding and releasing metal ions and a negative electrode capable of occluding and releasing metal ions, the negative electrode being a carbonaceous material or silicon The electricity storage device according to [11], including a material including:

[13] The plurality of electrodes that can occlude and release metal ions are a positive electrode that can occlude and release metal ions and a negative electrode that can occlude and release metal ions, and the positive electrode has the following composition formula (
The electricity storage device according to [11] to [12], which contains the transition metal oxide represented by a).
Li _a2 Ni _b2 Co _c2 M _d2 O ₂ (a)
(In the above formula (a), a2, b2, c2 and d2 are 0.90 ≦ a2 ≦ 1.10, 0.50.
≦ b2 ≦ 0.98, 0.01 ≦ c2 <0.50, 0.01 ≦ d2 <0.50 are shown, and b2 + c2 + d2 = 1 is satisfied. M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er. )

According to the nonaqueous electrolytic solution of the present invention, it is possible to provide an electricity storage device that is excellent in overall characteristics and less deteriorated.

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is limited to these specific contents. However, various modifications can be made within the scope of the invention.

[1. Non-aqueous electrolyte]
The nonaqueous electrolytic solution of the present invention contains a compound represented by the above general formula (1). Since the non-aqueous electrolyte solution is obtained by dissolving an electrolyte in a non-aqueous solvent, the electrolyte, the non-aqueous solvent, and the compound represented by the general formula (1) will be described below in this order.

<1-1. Electrolyte>
The electrolyte used for the non-aqueous electrolyte solution of the present invention is not particularly limited, and can be arbitrarily adopted depending on the characteristics of the target electricity storage device.
Specific examples of the electrolyte include, for example, LiClO ₄ , LiAsF ₆ , LiPF ₆ , Li
Inorganic lithium salts such as BF ₄ and LiAlF ₄ ;
LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO
_{2) (C 2 F 5 SO} 2), LiN (CF 3 SO 2) (C 3 F 7 SO 2), lithium cyclic 1,2-ethane sulfonyl imide, lithium cyclic 1,3-propanediol disulfonylimide, lithium Cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, lithium cyclic 1,4-perfluorobutanedisulfonylimide, LiC (CF ₃ SO ₂ ) ₃ , LiPF ₄ ( CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiP
F 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 ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) ₂ , LiBF ₂ (CF ₃ SO ₂ ) ₂ , L
fluorine-containing organic lithium salt such as iBF ₂ (C ₂ F ₅ SO ₂ ) ₂ ;
Sodium or potassium salts such as KPF ₆ , NaPF ₆ , NaBF ₄ , CF ₃ SO ₃ Na;
Etc.

Of these, lithium salts are preferred, and among them, LiPF ₆ , LiBF ₄ , LiCF ₃
SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide are preferable, LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ ,
LiN (CF ₃ SO ₂ ) ₂ is more preferable, and LiPF ₆ is particularly preferable.
Moreover, it is preferable that the non-aqueous electrolyte solution of the present invention contains hexafluorophosphate as an electrolyte. Hexafluorophosphate is preferred because the hexafluorophosphate anion is electrochemically stable, and this can improve the charge / discharge efficiency of the electricity storage device obtained using the non-aqueous electrolyte of the present invention. it can. Moreover, the said salt can make the dissociation degree of a salt very high, and can make the ion density | concentration used as a charge carrier in electrolyte solution high.

The electrolyte demonstrated above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Of these, the combined use of two inorganic lithium salts and the combined use of an inorganic lithium salt and a fluorine-containing organic lithium salt are preferable because gas generation during continuous charging of an electricity storage device or deterioration after high-temperature storage is effectively suppressed.
In particular, the combined use of LiPF ₆ and LiBF ₄ and the inclusion of inorganic lithium salts such as LiPF ₆ and LiBF ₄ and LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) _2, etc. The combined use with a fluorine organic lithium salt is preferred.

When LiPF ₆ and LiBF ₄ are used in combination, the proportion of LiBF _{4 in} the entire electrolyte is
It is preferable that it is 0.001 mass% or more and 20 mass% or less. L is within this range.
Since the dissociation degree of iBF ₄ is low, it is possible to suppress the resistance of the non-aqueous electrolyte from increasing.
On the other hand, inorganic lithium salts such as LiPF ₆ and LiBF ₄ and LiCF ₃ SO ₃ , LiN (CF _{3
SO 2) 2, LiN (C} 2 F 5 SO 2) When used in combination with a fluorine-containing organic lithium salt of _2, etc., the proportion of the inorganic lithium salt in the whole electrolyte is 70 mass% or more, 99.9% or less It is preferable that Within this range, the ratio of the fluorine-containing organic lithium salt having a large molecular weight is generally too high compared to hexafluorophosphate, and the ratio of the non-aqueous solvent in the entire non-aqueous electrolyte solution is reduced. An increase in the resistance of the aqueous electrolyte can be suppressed.

The concentration of the electrolyte such as lithium salt in the composition of the final electricity storage device of the non-aqueous electrolyte solution of the present invention is arbitrary as long as the effect of the present invention is not significantly impaired, but preferably 0.5 mo.
1 / L or more and 3 mol / L or less. If the electrolyte concentration is above this lower limit, sufficient ionic conductivity of the non-aqueous electrolyte can be easily obtained, and if it is lower than the upper limit, it is avoided that the viscosity increases excessively. As described above, it is easy to ensure good ion conductivity and performance of the electricity storage device.
The concentration of the electrolyte such as lithium salt is more preferably 0.6 mol / L or more, further preferably 0.8 mol / L or more, more preferably 2 mol / L or less, and further preferably 1.5 mol / L or more.
It is the range below mol / L.

<1-2. Nonaqueous solvent>
The non-aqueous solvent contained in the non-aqueous electrolyte solution of the present invention contains a cyclic carbonate as an essential component.
The kind of the cyclic carbonate is not particularly limited. Among them, the alkylene group constituting the cyclic carbonate preferably has 2 to 6 carbon atoms, particularly preferably 2 to 4 carbon atoms. Specific examples of the cyclic carbonate include ethylene carbonate, propylene carbonate, butylene carbonate (2-ethylethylene carbonate, cis and trans 2,3-dimethylethylene carbonate), 4-fluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4 , 5-difluoroethylene carbonate, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, ethynyl ethylene carbonate,
Examples include propargyl ethylene carbonate.

Among these, ethylene carbonate, propylene carbonate, 4-fluoroethylene carbonate, vinylene carbonate and vinyl ethylene carbonate are preferable as the cyclic carbonate because the resistance of the non-aqueous electrolyte storage device can be reduced due to the high dielectric constant. Ethylene carbonate, propylene carbonate, 4-fluoroethylene carbonate and vinylene carbonate are more preferable, and ethylene carbonate, 4-fluoroethylene carbonate and vinylene carbonate are particularly preferable.

It is also preferable to use a plurality of cyclic carbonates simultaneously, simultaneous use of ethylene carbonate and propylene carbonate, simultaneous use of ethylene carbonate and 4-fluoroethylene carbonate, simultaneous use of ethylene carbonate and vinylene carbonate, ethylene carbonate and 4-fluoroethylene carbonate, Simultaneous use of vinylene carbonate, 4-
The simultaneous use of fluoroethylene carbonate and vinylene carbonate, and the simultaneous use of propylene carbonate, 4-fluoroethylene carbonate and vinylene carbonate are particularly preferred.

Usually, it is used as a mixed solvent with a solvent other than the cyclic carbonate, but the solvent other than the cyclic carbonate is not particularly limited as long as it does not adversely affect the battery characteristics when used as an electricity storage device, but is listed below. It is preferable that it is 1 or more types in a nonaqueous solvent.
Examples of non-aqueous solvents other than cyclic carbonates include chain carbonates, chain carboxylic acid esters and cyclic carboxylic acid esters, chain ethers and cyclic ethers, phosphorus-containing organic solvents, sulfur-containing organic solvents, boron-containing organic solvents, and the like. Can be mentioned.

The kind of the chain carbonate is not particularly limited, and examples thereof include dialkyl carbonate. Among these, the alkyl group constituting the dialkyl carbonate preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. Specifically, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, di-n-propyl carbonate, and the like are preferable dialkyl carbonates.

Among these, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate are more preferable in terms of industrial availability and various characteristics in the electricity storage device.
Also, chain carbonates having fluorine atoms (hereinafter referred to as “fluorinated chain carbonate”)
Can also be used preferably. Although the number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, it is usually 6 or less, preferably 4 or less, more preferably 3 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 chain carbonate include fluorinated dimethyl carbonate, fluorinated ethyl methyl carbonate, and fluorinated diethyl carbonate.

Examples of the fluorinated dimethyl carbonate include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, and bis (trifluoromethyl) carbonate.
Examples of the fluorinated ethyl methyl carbonate include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

Examples of the fluorinated diethyl carbonate include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, and ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2
-Difluoroethyl-2'-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2'-fluoroethyl carbonate, 2,2,2-trifluoroethyl-2 Examples include ', 2'-difluoroethyl carbonate and bis (2,2,2-trifluoroethyl) carbonate.

The fluorinated chain carbonate is not only a non-aqueous solvent but also the following <1-4. Also effective as an additive described in <Additives>. There is no clear boundary in the blending amount when the fluorinated chain carbonate is used as the solvent and additive, and in this specification, the blending amount described as the blending amount as the non-aqueous solvent and the blending amount of the additive is used as it is. You can follow.
The type of the chain carboxylic acid ester is not particularly limited. For example, methyl acetate, ethyl acetate, acetic acid-n-propyl, acetic acid-i-propyl, acetic acid-n-butyl, acetic acid-i-butyl,
T-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, i-butyl propionate, t-butyl propionate, butyric acid Examples include methyl and ethyl butyrate.

Among these, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and ethyl butyrate are preferable in terms of industrial availability and various characteristics in an electricity storage device.
Further, the cyclic carboxylic acid ester is not particularly limited, and examples thereof include γ-butyrolactone, γ-valerolactone, and δ-valerolactone.

Among these, γ-butyrolactone is preferable in terms of industrial availability and various characteristics in an electricity storage device.
The type of the chain ether is not particularly limited, and examples thereof include dimethoxymethane, dimethoxyethane, diethoxymethane, diethoxyethane, ethoxymethoxymethane, and ethoxymethoxyethane.

Among these, dimethoxyethane and diethoxyethane are preferable in terms of industrial availability and various characteristics in the electricity storage device.
The cyclic ether is not particularly limited, and examples thereof include tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran and the like.
The phosphorus-containing organic solvent is not particularly limited. For example, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tris phosphate (2,2,2-trifluoroethyl), trimethyl phosphite, triethyl phosphite, phosphorous acid. Triphenyl, trimethylphosphine oxide,
Examples thereof include triethylphosphine oxide and triphenylphosphine oxide.

The kind of the sulfur-containing organic solvent is not particularly limited, and examples thereof include ethylene sulfite, 1,3-propane sultone, 1,4-butane sultone, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolane, sulfolene, Dimethyl sulfone, ethyl methyl sulfone, diphenyl sulfone, methyl phenyl sulfone, dibutyl disulfide, dicyclohexyl disulfide, tetramethyl thiuram monosulfide, N, N-
Examples thereof include dimethylmethanesulfonamide and N, N-diethylmethanesulfonamide.

The boron-containing organic solvent is not particularly limited, and examples thereof include boroxines such as 2,4,6-trimethylboroxine and 2,4,6-triethylboroxine.
Among the non-aqueous solvents described above, a chain carbonate or a chain carboxylic acid ester and a cyclic carboxylic acid ester are preferable in terms of various characteristics in the electricity storage device, and among these, dimethyl carbonate, ethyl methyl carbonate, Diethyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, γ -Butyrolactone is more preferred, such as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate Preferred.

One preferred combination of non-aqueous solvents is a combination mainly composed of cyclic carbonates and chain carbonates. Among them, the total of the cyclic carbonates and the chain carbonates in the whole non-aqueous solvent is preferably 80% by volume or more, more preferably 85% by volume or more, and particularly preferably 90% by volume or more. The volume ratio of the carbonic acid to the chain carbonate (total volume of the cyclic carbonate: total volume of the chain carbonate) is preferably 0.
5: 9.5 to 7: 3, more preferably 1: 9 to 5: 5, still more preferably 1.5: 8.5
4: 6, particularly preferably a combination of 2: 8 to 3.5: 6.5. An electricity storage device manufactured using a combination of these nonaqueous solvents is preferable because the balance between cycle characteristics and high-temperature storage characteristics (particularly, remaining capacity and high-load discharge capacity after high-temperature storage) is improved.

Examples of preferred combinations of cyclic carbonates and chain carbonates include combinations of ethylene carbonate and chain carbonates, such as ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, Examples thereof include ethylene carbonate, dimethyl carbonate and diethyl carbonate, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

A combination in which propylene carbonate is further added to the combination of these ethylene carbonate and chain carbonate is also preferable. When propylene carbonate is contained, the volume ratio of ethylene carbonate to propylene carbonate is 99: 1 to 4 as described above.
The capacity ratio needs to be 0:60, and the volume ratio is preferably 95: 5 to 45:55, and more preferably 85:15 to 50:50. Furthermore, when the amount of propylene carbonate in the entire non-aqueous solvent is 0.1% by volume or more and 10% by volume or less, further excellent discharge is maintained while maintaining the characteristics of the combination of ethylene carbonate and chain carbonates. This is preferable because load characteristics can be obtained. The amount of propylene carbonate in the entire non-aqueous solvent is
More preferably, it is 1% by volume, particularly preferably 2% by volume or more, and more preferably 8% by volume.
It is not more than volume%, particularly preferably not more than 5 volume%.

Among these, those containing asymmetric chain carbonates as chain carbonates are more preferable, in particular, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate,
Those containing ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, or those containing propylene carbonate in addition to these, are preferable because the balance between the cycle characteristics and discharge load characteristics of the electricity storage device is good.
In particular, it is preferable that the asymmetric chain carbonate is ethyl methyl carbonate, and it is preferable that the alkyl group constituting the dialkyl carbonate has 1 to 2 carbon atoms.

Other examples of non-aqueous solvents preferable in the present invention are those containing chain carboxylic acid esters. In particular, those containing a chain carboxylic acid ester in the mixed solvent of cyclic carbonates and chain carbonates are preferable from the viewpoint of improving the discharge load characteristics of the electricity storage device. In this case, the chain carboxylic acid esters Particularly preferred are methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and ethyl butyrate. The volume of the chain carboxylic acid esters in the non-aqueous solvent is preferably 5% by volume or more, more preferably 8% by volume or more, particularly preferably 10% by volume or more, preferably 50% by volume or less, more preferably 35% by volume or less, particularly preferably 30% by volume or less, particularly preferably 25% by volume or less.
The capacity is less than%.

In the present invention, regarding the ratio of the content of the cyclic carbonate and the electrolyte, the content of the cyclic carbonate is preferably less than 4 times the content of the electrolyte. More preferably, the content of cyclic carbonate is 3 times or less the content of electrolyte, more preferably the content of cyclic carbonate is 2.8 or less of the content of electrolyte, More preferably, the content of the electrolyte is 2.7 times or less of the content of the electrolyte, and the content of the cyclic carbonate is particularly preferably 2.6 times or less of the content of the electrolyte. The amount of contained material is 2.5 of the amount of contained electrolyte.
Most preferably, it is less than 2 times. The reason is described below.

In general, in the case of a non-aqueous electrolyte solution using a cyclic carbonate solvent, the cyclic carbonate has a large dielectric constant, and thus is considered to coordinate with the highest priority to the cation from which the electrolyte is dissociated. Referring to Non-Patent Document 1, when the cyclic carbonate 4 molecules are stable to coordinate to the cations from which the electrolyte is dissociated, the amount of the cyclic carbonate contained is 4 times or more the amount of the electrolyte contained It can be presumed that 4 molecules of cyclic carbonate are coordinated to one cation from which the electrolyte is dissociated. In the present invention, in the present invention, since the content of the cyclic carbonate is less than 4 times the content of the electrolyte, the cyclic carbonate can coordinate to the cation generated by the dissociation of the electrolyte with 4 molecules. In other words, a coordination state of 3 molecules or less exists.

It is known that the solvent of the nonaqueous electrolytic solution reacts on the negative electrode to form a film. This is because, as described above, the solvent component is coordinated to the cation from which the electrolyte serving as the ion-conducting carrier is dissociated, so that the solvent molecules approach the negative electrode surface as the cation moves. Therefore, as described above, when the solvent molecule coordinated with the cation changes, the component of the coating on the negative electrode changes. If the amount of cyclic carbonate contained is less than 3 times the amount of electrolyte contained, the cyclic carbonate 3-coordinated cation is mainly used, and the excess solvent is prevented from approaching the negative electrode. And excessive film formation is suppressed. When the amount of the cyclic carbonate contained is 2.8 times or less of the amount of the electrolyte contained, the excessive formation of the film is suppressed, and the additive compound described later contributes to the film formation efficiently. Can do. When the amount of the cyclic carbonate-containing substance is 2.7 times or less of the amount of the electrolyte-containing substance, the anion of the electrolyte remains coordinated to the cation, which can contribute to film formation.

<1-3. Compound represented by general formula (1)>
The non-aqueous electrolyte solution of the present invention is a compound represented by the following general formula (1) (hereinafter referred to as “specific compound”).
As an essential component. In the non-aqueous electrolyte solution of the present invention, one of the specific compounds may be used, or two or more may be used in any combination and ratio.

(In the formula ^(1), R 1 ~R ^3, which may be the being the same or different, is an organic group having 1 to 20 carbon atoms that may have a substituent. However, R ¹ at least one of to R ³ is a carbon - carbon unsaturated bond or a cyano group).
In the present invention, by using a non-aqueous electrolyte solution containing a specific compound, preferably having a cyclic carbonate content of less than 4 times the content of electrolyte, it is possible to suppress deterioration of the characteristics of the electricity storage device to a small level. It becomes possible. Although this action and principle are not clear, the present inventors consider as follows. However, the present invention is not limited to the operations and principles described below.

Specific compounds contain multiple bonds of electrochemically reduced carbon-carbon unsaturated bonds or cyano groups in the molecular structure, which contributes to the negative electrode protection by reacting on the negative electrode to form a crosslinkable film. it is conceivable that.
Moreover, <1-2. As described in the section of “Nonaqueous Solvent>, it is known that a solvent component of a nonaqueous electrolyte solution reacts on the negative electrode to form a film in addition to a compound called an additive such as a specific compound. . This is because the solvent component is coordinated to the cation from which the electrolyte serving as the ion-conducting carrier is dissociated, so that the solvent molecules approach the negative electrode surface as the cation moves. Therefore, when the solvent molecule coordinated with the cation changes, the component of the coating on the negative electrode changes. Normally, in the case of a non-aqueous electrolyte solution using a cyclic carbonate solvent, the cyclic carbonate has a large dielectric constant, so it coordinates with the highest priority to the cations from which the electrolyte is dissociated, It has become.

In the non-aqueous electrolyte solution of the present invention, the substance amount ratio between the electrolyte and the cyclic carbonate is controlled, and at the same time, the specific compound is used as a raw material for the coating, so that the components of the coating on the negative electrode are optimally controlled. It is estimated that the characteristics are obtained. The specific compound has a large number of polarization structures, and is characterized in that it does not easily become a resistance component by interacting with a cation in which an electrolyte such as lithium ion is dissociated.

In the general formula (1), R ^{1 to} R ³ may be the same as or different from each other, and may be an organic group having 1 to 20 carbon atoms that may have a substituent. However, at least one of R ^{1 to} R ³ has a carbon-carbon unsaturated bond or a cyano group. Preferably, in formula (1):
R ^{1 to} R ³ may be the same as or different from each other, and may be an organic group having 1 to 10 carbon atoms that may have a substituent. More preferably, in formula (1), at least one of R ^{1 to} R ³
One is an organic group having a carbon-carbon unsaturated bond.

Here, the organic group represents a functional group composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom and a halogen atom.
Specific examples of the organic group that may have a substituent include an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, a cyano group, an acrylic group, a methacryl group, a vinylsulfonyl group, a vinylsulfo group, and the like. Is mentioned.

Examples of the substituent herein include a halogen atom and an alkylene group. Moreover, an unsaturated bond etc. may be contained in a part of alkylene group. Of the halogen atoms, a fluorine atom is preferred.
Specific examples of the alkyl group which may have a substituent include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group and a tert-butyl group. Examples thereof include a linear or branched alkyl group or a cyclic alkyl group such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

Specific examples of the alkenyl group that may have a substituent include a vinyl group, an allyl group, a methallyl group, and a 1-propenyl group. Specific examples of the alkynyl group which may have a substituent include ethynyl group, propargyl group, 1-propynyl group and the like. Specific examples of the aryl group which may have a substituent include a phenyl group, a tolyl group, a benzyl group,
A phenethyl group etc. are mentioned.

Among these, an alkyl group, an alkenyl group, an alkynyl group, an acrylic group, a methacryl group, an aryl group, a cyano group, a vinylsulfonyl group, and a vinylsulfo group that may have a substituent are preferable.
More preferably, an alkyl group, an alkenyl group, an alkynyl group, an acrylic group, a methacryl group, or a cyano group, which may have a substituent, may be mentioned.

Particularly preferably, an alkyl group, an alkenyl group, an acrylic group, which may have a substituent,
A methacryl group and a cyano group are mentioned.
Most preferably, the alkyl group, allyl group, and methallyl group which may have a substituent are mentioned. In particular, an allyl group or a methallyl group which is an organic group having an unsubstituted carbon-carbon unsaturated bond is preferable. An allyl group is preferable from the viewpoint of film forming ability.

Although the compound used for this invention is a compound which has a structure shown by General formula (1), the compound of the following structures is mentioned as the specific example.

  Preferably, the compound of the following structures is mentioned.

  More preferably, the compound of the following structures is mentioned.

  Particularly preferred are compounds having the following structures.

  Most preferably, the compound of the following structure is mentioned.

Of these most preferred compounds, compounds having the following structure are preferred from the viewpoint of film-forming ability.

With respect to the specific compound, there is no particular limitation on the production method, and any known method can be selected and produced.
The ratio of the specific compounds in the non-aqueous electrolyte is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, preferably 10% by mass or less, more preferably 4.5% by mass in total. Hereinafter, it is more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1.8% by mass or less, and most preferably 1.6% by mass or less. If the concentration of the specific compound is excessive, there are too many reduction products, so that the surface of the negative electrode is excessively covered and the electrode reaction is inhibited. Moreover, the cost of a non-aqueous electrolyte solution will also increase. If it is said density | concentration, since the effect | action in an electrode interface will advance more suitably, it will become possible to optimize a battery characteristic.

<1-4. Additives>
The nonaqueous electrolytic solution of the present invention may contain various additives as long as the effects of the present invention are not significantly impaired. A conventionally well-known thing can be arbitrarily used for an additive. An additive may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Examples of the additive include an overcharge inhibitor and an auxiliary agent for improving capacity retention characteristics and cycle characteristics of the electricity storage device after high temperature storage. Among these, as an auxiliary agent for suppressing capacity maintenance characteristics and resistance increase after high temperature storage, difluorophosphate, fluorosulfate,
And at least one compound selected from the group consisting of a dicarboxylic acid complex salt (hereinafter sometimes abbreviated as “specific additive”). Hereinafter, the specific additive and other additives will be described separately.

<1-4-1. Specific additive>
The specific additive is a compound that reacts on the positive electrode, and is considered to form a surface structure suitable for the electrode reaction.
The molecular weight of the specific additive is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired, but those having a molecular weight of 50 or more and 250 or less are preferable. Within this range, the solubility of the specific additive in the non-aqueous electrolyte solution is good, and the effect of addition can be sufficiently exhibited.

Moreover, there is no restriction | limiting in particular also in the manufacturing method of a specific additive, It is possible to select and manufacture a well-known method arbitrarily. A commercially available product may also be used.
In addition, the specific additive may be included alone in the nonaqueous electrolytic solution of the present invention, or two or more specific additives may be combined in any combination and ratio.

<1-4-1-1. Difluorophosphate>
Among the specific additives, the difluorophosphate is not particularly limited as long as it is a salt having a difluorophosphate anion as a constituent element, and any difluorophosphate can be used.
Examples of the difluorophosphate include lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate, ammonium difluorophosphate, and the like.

Among these, lithium difluorophosphate is preferable, can contribute to the formation of a stable film-like structure, and is more preferably used.
The content of the difluorophosphate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired. However, the content of the difluorophosphate is preferably 0.001% by mass or more, 2
. 0% by mass or less.

When the content of difluorophosphate is at least the lower limit, a sufficient effect of improving cycle characteristics can be provided to the non-aqueous electrolyte secondary battery. Moreover, the increase in the manufacturing cost of a non-aqueous electrolyte secondary battery can be avoided as it is below this upper limit. The content of difluorophosphate is more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and more preferably 1.5% by mass or less. More preferably 1.2
It is at most 1.1 mass%, particularly preferably at most 1.1 mass%.

<1-4-1-2. Fluorosulfate>
Among the specific additives, the fluorosulfate is not particularly limited as long as it is a salt having a fluorosulfuric acid anion as a constituent element, and any fluorosulfate can be used.
Examples of fluorosulfates include lithium fluorosulfate, sodium fluorosulfate,
Examples include potassium fluorosulfate and ammonium fluorosulfate.

Among these, lithium fluorosulfate is preferable, can contribute to the formation of a stable film-like structure, and is more preferably used.
The content of the fluorosulfate is not particularly limited, and may be arbitrary as long as the effects of the present invention are not significantly impaired.
It is below mass%.

When the content of the fluorosulfate is equal to or higher than this lower limit, a sufficient effect of improving cycle characteristics can be provided to the non-aqueous electrolyte secondary battery. Further, if it is below this upper limit, it is possible to avoid an increase in the manufacturing cost of the non-aqueous electrolyte secondary battery, and corrosion of aluminum frequently used for the positive electrode current collector and metal can often used for the exterior body. Performance degradation due to can be avoided. The content of fluorosulfate is more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and more preferably 3.0% by mass or less. More preferably, it is 2.5 mass% or less, Most preferably, it is 2.0 mass% or less.

<1-4-1-3. Dicarboxylic acid complex salt>
Among the specific additives, the dicarboxylic acid complex salt is not particularly limited, and any dicarboxylic acid complex salt can be used.
Examples of dicarboxylic acid complex salts include dicarboxylic acid complex salts whose complex central element is boron,
Examples thereof include dicarboxylic acid complex salts whose complex central element is phosphorus.

Specific examples of the dicarboxylic acid complex salt whose complex central element is boron include lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium bis (malonate) borate, lithium difluoro (malonato) borate, lithium bis (methylmalonate) Examples thereof include borate, lithium difluoro (methylmalonate) borate, lithium bis (dimethylmalonate) borate, and lithium difluoro (dimethylmalonate) borate.

Specific examples of the dicarboxylic acid complex salt in which the complex element is phosphorus include lithium tris (oxalato) phosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluoro (oxalato) phosphate, lithium tris (malonato) phosphate, lithium difluorobis (Malonate) phosphate, lithium tetrafluoro (malonate) phosphate, lithium tris (methylmalonate) phosphate, lithium difluorobis (methylmalonate) phosphate, lithium tetrafluoro (methylmalonate)
Phosphate, lithium tris (dimethylmalonate) phosphate, lithium difluorobis (dimethylmalonate) phosphate, lithium tetrafluoro (dimethylmalonate)
A phosphate etc. are mentioned.

Among them, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium tris (oxalato) phosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluoro (oxalato) phosphate, readily available and stable film-like structure From the point which can contribute to formation of this, it uses more suitably.

The content of the dicarboxylic acid complex salt is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. However, the content of the dicarboxylic acid complex salt is preferably 0.001% by mass or more with respect to the nonaqueous electrolytic solution of the present invention.
. 5% by mass or less.
When the content of the dicarboxylic acid complex salt is equal to or higher than this lower limit, a sufficient effect of improving cycle characteristics can be provided to the non-aqueous electrolyte secondary battery. Moreover, when it is below this upper limit, the increase in the manufacturing cost of a non-aqueous electrolyte secondary battery can be avoided, and the volume expansion of the non-aqueous electrolyte secondary battery due to gas generation can be avoided. The content of the dicarboxylic acid complex salt is more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, and particularly preferably 0.2% by mass.
More preferably, it is 2.0 mass% or less, More preferably, it is 1.5 mass% or less, Most preferably, it is 1.2 mass% or less.

<1-4-1-4. Preferred specific additive>
The specific additive preferably contains at least one compound selected from a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a difluorophosphate, and a fluorosulfate, One or more specific additives from a cyclic carbonate having a fluorine atom or a cyclic carbonate having a carbon-carbon unsaturated bond, and one or more specific compounds from a difluorophosphate or a fluorosulfate may be contained simultaneously. More preferably, among them, it is particularly preferable to simultaneously contain one or more specific compounds from a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a difluorophosphate, and a fluorosulfate.

<1-4-2. Other additives>
Examples of additives other than the specific additive include an overcharge inhibitor, an auxiliary agent for improving capacity retention characteristics and cycle characteristics after high-temperature storage, and the like.

<1-4-2-1. Overcharge prevention agent>
Specific examples of the overcharge inhibitor include toluene derivatives such as toluene, xylene, 2-fluorotoluene, 3-fluorotoluene, 4-fluorotoluene;
Biphenyl derivatives unsubstituted or substituted with alkyl groups, such as biphenyl, 2-methylbiphenyl, 3-methylbiphenyl, 4-methylbiphenyl;
terphenyl derivatives unsubstituted or substituted with alkyl groups such as o-terphenyl, m-terphenyl, p-terphenyl;
Partial hydrides of terphenyl derivatives unsubstituted or substituted with alkyl groups;
Cycloalkylbenzene derivatives such as cyclopentylbenzene and cyclohexylbenzene;
Alkylbenzene derivatives having a tertiary carbon directly bonded to a benzene ring such as cumene, 1,3-diisopropylbenzene, 1,4-diisopropylbenzene;
alkylbenzene derivatives having a quaternary carbon directly bonded to a benzene ring, such as t-butylbenzene, t-amylbenzene, t-hexylbenzene, 1,1,3-trimethyl-3-phenylindane;
Aromatic compounds having an oxygen atom such as diphenyl ether and dibenzofuran;
Aromatic compounds such as

Furthermore, specific examples of other overcharge inhibitors include partially fluorinated products of the aromatic compounds such as fluorobenzene, benzotrifluoride, 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; Fluorine-containing anisole compounds such as 4-difluoroanisole, 2,5-difluoroanisole and 1,6-difluoroanisole;

In addition, these overcharge inhibitors may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. Moreover, when using together by arbitrary combinations, you may use together by the compound of the same classification illustrated above, and you may use together by a compound of a different classification | category.
When the overcharge inhibitor is blended, the amount of the overcharge inhibitor is arbitrary as long as the effects of the present invention are not significantly impaired, but the total amount of non-aqueous electrolyte is preferably 0.1%. 0
It is the range of 01 mass% or more and 10 mass% or less.

By including an overcharge inhibitor in the non-aqueous electrolyte of the present invention within a range that does not significantly impair the effects of the present invention, an overcharge protection circuit such as an incorrect usage or an abnormality of the charging device should operate normally. This is preferable because the safety of the electricity storage device can be improved so that there is no problem even if the battery is overcharged.

<1-4-2-2. Auxiliary>
On the other hand, specific examples of the auxiliary for improving capacity maintenance characteristics and cycle characteristics after high-temperature storage include the following.
Carbonate compounds other than those corresponding to carbonates having an unsaturated bond such as erythritan carbonate and spiro-bis-dimethylene carbonate;
Cyclic sulfites such as ethylene sulfite;
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-
1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-propene-
Sultone compounds such as 1,3-sultone;
Ethylene sulfate, 1,3,2-dioxathiolane 2,2-dioxide, 4-ethyl-1,3,2-dioxathiolane 2,2-dioxide, 4-propyl-1,3,2-dioxathiolane 2,2-dioxide, etc. Cyclic sulfates of
Chain sulfonate esters such as methyl methanesulfonate and busulfan;
Sulfolane, sulfolene, 1,3-dithietane-1,1,3,3-tetraoxide, 2,
Cyclic sulfones such as 4-diethyl-1,3-dithietane-1,1,3,3-tetraoxide;
Chain sulfones such as dimethyl sulfone, diphenyl sulfone, and methylphenyl sulfone;
Sulfides such as dibutyl disulfide, dicyclohexyl disulfide, tetramethylthiuram monosulfide;
Sulfur-containing compounds such as sulfonamides such as N, N-dimethylmethanesulfonamide and 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;
Hydrocarbon compounds such as heptane, octane, cycloheptane;
2- (diethoxyphosphoryl) acetic acid propargyl, 2- (diethoxyphosphoryl) acetic acid 2
-Butynyl, propargyl 2- (methanesulfonyloxy) propionate, propargyl methanesulfonyloxyacetate, lithium ethyl-propargyloxycarbonylphosphonate, lithium ethyl-2-butynyloxycarbonylphosphonate, lithium propargyl sulfate, 2-butynyllithium sulfate, Propargyl trimethylsilyl sulfate, 2-butyne-1,4-diyl dimesylate, 2-butyne-1,4-diyl diethanesulfonate, 2-butyne-1,4-diyl diformate, 2-butyne-1,4-diyl diacetate 2-butyne-1,4-diyl dipropionate, 4-hexadiyne-1,6
-Diyl dimethanesulfonate, propargyl methanesulfonate, methanesulfonic acid 2
-Butynyl, propargyl ethanesulfonate, propargyl vinylsulfonate, propargyl methyl carbonate, propargyl ethyl carbonate, dipropargyl carbonate, propargyl formate, propargyl acetate, propargyl methacrylate, methyl propargyl oxalate, ethyl propargyl oxalate, dipropargyl oxalate Triple bond compounds such as;
Fluorine-containing aromatic compounds such as fluorobenzene, difluorobenzene, and benzotrifluoride;
Pentafluorophenyl methanesulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl acetate, pentafluorophenyl trifluoroacetate,
Pentafluorophenyl compounds such as methyl pentafluorophenyl carbonate;
Sulfuric acid half esters such as lithium methylsulfate, lithium ethylsulfate, sodium methylsulfate and sodium ethylsulfate.

In addition, these adjuvants may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
Moreover, when the non-aqueous electrolyte of the present invention contains these auxiliaries, the content thereof is arbitrary as long as the effects of the present invention are not significantly impaired, but with respect to the entire non-aqueous electrolyte (100% by mass). ,
Preferably it is 0.001 mass% or more and 10 mass% or less.

<1-5. Method for producing non-aqueous electrolyte>
The non-aqueous electrolyte solution of the present invention can be prepared by dissolving the electrolyte, the specific ether, and the above-mentioned “specific additive” and “other additive”, if necessary, in the above-described non-aqueous solvent. it can.
When preparing the non-aqueous electrolyte, each raw material of the non-aqueous electrolyte, that is, an electrolyte such as a lithium salt, a specific ether, a non-aqueous solvent, a specific additive, and other additives may be dehydrated in advance. preferable. The degree of dehydration is usually 50 ppm or less, preferably 30 ppm or less.

By removing water in the non-aqueous electrolyte, water electrolysis, water and lithium metal reaction,
Hydrolysis of the lithium salt is difficult to occur. The dehydration means is not particularly limited. For example, when the object to be dehydrated is a liquid such as a non-aqueous solvent, a desiccant such as molecular sieve may be used. In addition, when the object to be dehydrated is a solid such as an electrolyte, it may be dried by heating at a temperature lower than the temperature at which decomposition occurs.

[2. Power storage device using non-aqueous electrolyte]
An electricity storage device using the non-aqueous electrolyte of the present invention comprises a plurality of electrodes capable of occluding or releasing metal ions and the non-aqueous electrolyte of the present invention described above. Specific examples of power storage devices include primary batteries, secondary batteries, and metal ion capacitors including lithium ion capacitors. Among these, a primary battery or a secondary battery is preferable,
Secondary batteries are particularly preferred. In addition, it is also preferable that the non-aqueous electrolyte solution used for these electrical storage devices is what is called a gel electrolyte quasi-solidified with a polymer, a filler, or the like. Hereinafter, the power storage device will be described.

<2-1. Non-aqueous electrolyte secondary battery>
<2-1-1. Battery configuration>
The non-aqueous electrolyte secondary battery of the present invention is the same as the conventionally known non-aqueous electrolyte secondary battery except for the non-aqueous electrolyte, and is usually impregnated with the non-aqueous electrolyte of the present invention. The positive electrode and the negative electrode are laminated via a porous film (separator), and these are housed in a case (exterior body). Therefore, the shape of the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

<2-1-2. Non-aqueous electrolyte>
As the non-aqueous electrolyte, the above-described non-aqueous electrolyte of the present invention is used. In addition, in the range which does not deviate from the meaning of this invention, it is also possible to mix and use other nonaqueous electrolyte solution with respect to the nonaqueous electrolyte solution of this invention.

<2-1-3. Negative electrode>
The negative electrode active material used for the negative electrode is not particularly limited as long as it can electrochemically occlude and release metal ions. Specific examples thereof include carbonaceous materials, metal compound materials, lithium-containing metal composite oxide materials, and the like. One of these may be used alone, or two or more may be used in any combination.

Of these, carbonaceous materials and metal compound-based materials are preferable. Among the metal compound-based materials, a material containing silicon is preferable. Therefore, as the negative electrode active material, a carbonaceous material and a material containing silicon are particularly preferable. From the viewpoint of capacity and suppression of deterioration, it is most preferable to use a mixture of a carbonaceous material and a metal compound material.

<2-1-3-1. Carbonaceous material>
Although it does not specifically limit as a carbonaceous material used as a negative electrode active material, The following (a)-
What is selected from (d) is preferable because it provides a secondary battery having a good balance between initial irreversible capacity and high current density charge / discharge characteristics.

(A) Natural graphite (A) Carbonaceous material obtained by heat-treating artificial carbonaceous material and artificial graphite material at least once in the range of 400 ° C. to 3200 ° C. (C) There are at least two types of negative electrode active material layers It consists of carbonaceous materials with different crystallinity,
And / or a carbonaceous material having an interface with which the different crystalline carbonaceous materials are in contact (d) the negative electrode active material layer is composed of carbonaceous materials having at least two different orientations;
And / or a carbonaceous material having an interface where carbonaceous materials having different orientations contact each other (a) to (d) may be used alone or in any combination of two or more. And may be used in combination in a ratio.

Specific examples of the artificial carbonaceous material or artificial graphite material in (i) above include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, and those obtained by oxidizing these pitches;
Needle coke, pitch coke and carbon materials partially graphitized from these;
Thermal decomposition products of organic substances such as furnace black, acetylene black and pitch-based carbon fiber;
Carbonizable organics and their carbides; and
Examples thereof include a solution-like carbide obtained by dissolving a carbonizable organic substance in a low-molecular organic solvent such as benzene, toluene, xylene, quinoline, and n-hexane.
In addition, the carbonaceous materials (a) to (d) above are conventionally known, and their production methods are well known to those skilled in the art, and these commercial products can also be purchased.

<2-1-3-2. Structure, physical properties, preparation method of negative electrode using metal compound material and metal compound material>
As the metal compound material used as the negative electrode active material, if lithium can be occluded / released, a simple metal or alloy that forms a lithium alloy, or oxides, carbides thereof,
Any compound such as nitride, silicide, sulfide and phosphide is not particularly limited. Examples of such metal compounds include Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni,
Examples thereof include compounds containing metals such as Pb, Sb, Si, Sn, Sr, and Zn. Among these, a single metal or an alloy that forms a lithium alloy is preferable.
It is more preferable that there is a material containing a group metal / metalloid element (that is, excluding carbon), and further, silicon (Si), tin (Sn), or lead (Pb) (hereinafter, these three elements are specified. It is preferably a single metal or an alloy containing these atoms, or a compound of these metals (specific metal elements), a simple metal of silicon, an alloy and a compound, and a simple substance of tin. Metals, alloys and compounds are particularly preferred. These may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

Examples of the negative electrode active material having at least one kind of atom selected from the specific metal element include a single metal element of any one specific metal element, an alloy composed of two or more specific metal elements, one type, or two
An alloy comprising one or more specific metal elements and one or more other metal elements, and
Examples thereof include compounds containing one or more specific metal elements, or composite compounds of the compounds such as oxides, carbides, nitrides, silicides, sulfides and phosphides. By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

Moreover, the compound which these complex compounds combined with several elements, such as a metal simple substance, an alloy, or a nonmetallic element, can also be mentioned as an example. More specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. In addition, for example, in the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element can also be used. .

Among these negative electrode active materials, since the capacity per unit mass is large when a battery is formed, any one metal element of a specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element In particular, silicon and / or tin metal, alloy, oxide, carbide, nitride and the like are preferable from the viewpoint of capacity per unit mass and environmental load.

In addition, although the capacity per unit mass is inferior to that of using a single metal or an alloy, the following compounds containing silicon and / or tin are also preferred because of excellent cycle characteristics.
The elemental ratio of silicon and / or tin to oxygen is usually 0.5 or more, preferably 0
. 7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably 1.3
Hereinafter, more preferably 1.1 or less “oxide of silicon and / or tin”.
-Element ratio of silicon and / or tin to nitrogen is usually 0.5 or more, preferably 0
. 7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably 1.3
Hereinafter, “silicon nitride and / or tin nitride” of 1.1 or less is more preferable.
-Element ratio of silicon and / or tin to carbon is usually 0.5 or more, preferably 0
. 7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably 1.3
Hereinafter, “carbide of silicon and / or tin” of 1.1 or less is more preferable.

In addition, any one of the above-described negative electrode active materials may be used alone, or two or more thereof may be used in any combination and ratio.
The negative electrode in the non-aqueous electrolyte battery of the present invention can be manufactured using any known method. Specifically, as a manufacturing method of the negative electrode, for example, a method in which a negative electrode active material added with a binder or a conductive material is roll-formed as it is to form a sheet electrode, or a compression-molded pellet electrode and The above negative electrode is usually applied to a negative electrode current collector (hereinafter also referred to as “negative electrode current collector”) by a method such as a coating method, a vapor deposition method, a sputtering method, or a plating method. A method of forming a thin film layer (negative electrode active material layer) containing an active material is used. in this case,
By adding a binder, a thickener, a conductive material, a solvent, etc. to the negative electrode active material described above to form a slurry, which is applied to the negative electrode current collector, dried and then pressed to increase the density, A negative electrode active material layer is formed on the electric body.

Examples of the material of the negative electrode current collector include steel, copper alloy, nickel, nickel alloy, and stainless steel. Of these, copper foil is preferred from the viewpoint of easy processing into a thin film and cost.
The thickness of the negative electrode current collector is usually 1 μm or more, preferably 5 μm or more.
It is 0 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.

In addition, in order to improve the binding effect with the negative electrode active material layer formed on the surface, the surface of these negative electrode current collectors is preferably subjected to a roughening treatment in advance. Surface roughening methods include blasting, rolling with a rough roll, abrasive cloth paper with abrasive particles fixed, grindstone, emery buff,
Examples thereof include a mechanical polishing method, an electrolytic polishing method, a chemical polishing method, and the like that polish the surface of the current collector with a wire brush provided with a steel wire or the like.

The slurry for forming the negative electrode active material layer is usually prepared by adding a binder, a thickener and the like to the negative electrode material. In addition, the “negative electrode material” in this specification refers to a material in which a negative electrode active material and a conductive material are combined.
The content of the negative electrode active material in the negative electrode material is usually 70% by mass or more, particularly preferably 75% by mass or more, and usually 97% by mass or less, particularly preferably 95% by mass or less. When the content of the negative electrode active material is too small, the capacity of the secondary battery using the obtained negative electrode tends to be insufficient, and when the content is too large, the content of the binder or the like is relatively insufficient. This is because the strength of the negative electrode tends to be insufficient. When two or more negative electrode active materials are used in combination, the total amount of the negative electrode active materials may be set to satisfy the above range.

Examples of the conductive material used for the negative electrode include metal materials such as copper and nickel; carbon materials such as graphite and carbon black. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. In particular, it is preferable to use a carbon material as the conductive material because the carbon material acts as an active material. The content of the conductive material in the negative electrode material is usually 3
% By mass or more, preferably 5% by mass or more, and usually 30% by mass or less, particularly 25% by mass.
The following is preferred. When the content of the conductive material is too small, the conductivity tends to be insufficient. When the content is too large, the content of the negative electrode active material or the like is relatively insufficient, which tends to decrease the battery capacity and strength. . Note that when two or more conductive materials are used in combination, the total amount of the conductive materials may satisfy the above range.

As the binder used for the negative electrode, any material can be used as long as it is a material safe with respect to the solvent and the electrolytic solution used at the time of producing the electrode. Examples thereof include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene / butadiene rubber / isoprene rubber, butadiene rubber, ethylene-acrylic acid copolymer, and ethylene / methacrylic acid copolymer. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The content of the binder is usually 0.5 parts by mass or more, particularly preferably 1 part by mass or more, and usually 10 parts by mass or less, particularly preferably 8 parts by mass or less, with respect to 100 parts by mass of the negative electrode material. When the content of the binder is too small, the strength of the obtained negative electrode tends to be insufficient. When the content is too large, the content of the negative electrode active material and the like is relatively insufficient, and thus the battery capacity and conductivity tend to be insufficient. It is because it becomes. When using two or more binders together,
What is necessary is just to make it the total amount of a binder satisfy | fill the said range.

As the thickener used for the negative electrode, carboxymethylcellulose, methylcellulose,
Examples thereof include hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein. One of these may be used alone, or 2
You may use a seed or more together by arbitrary combinations and ratios. The thickener may be used as necessary, but when used, the content of the thickener in the negative electrode active material layer is usually 0.5% by mass.
It is preferably used in the range of 5% by mass or less.

The slurry for forming the negative electrode active material layer is prepared by mixing the negative electrode active material with a conductive material, a binder, or a thickener as necessary, and using an aqueous solvent or an organic solvent as a dispersion medium. . As the aqueous solvent, water is usually used, but a solvent other than water such as alcohols such as ethanol or cyclic amides such as N-methylpyrrolidone is used in combination at a ratio of about 30% by mass or less with respect to water. You can also As the organic solvent, usually, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and aromatic carbonization such as anisole, toluene and xylene Examples thereof include alcohols such as hydrogens, butanol and cyclohexanol, among which cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide are preferable. . Any one of these may be used alone, or two or more may be used in any combination and ratio.

The viscosity of the slurry is not particularly limited as long as it is a viscosity that can be applied onto the current collector. What is necessary is just to prepare suitably by changing the usage-amount of a solvent etc. at the time of preparation of a slurry so that it may become the viscosity which can be apply | coated.
The obtained slurry is applied onto the above-described negative electrode current collector, dried, and then pressed to form a negative electrode active material layer. The method of application is not particularly limited, and a method known per se can be used. The drying method is not particularly limited, and a known method such as natural drying, heat drying, or reduced pressure drying can be used.

The electrode structure when the negative electrode active material is made into an electrode by the above method is not particularly limited, but the density of the active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ^-3
Or more, more preferably 1.3 g · cm ⁻³ or more, and usually 2.2 g · cm ^3.
cm ⁻³ or less is preferable, 2.1 g · cm ⁻³ or less is more preferable, and 2.0 g · cm ^−3.
The following is more preferable, and 1.9 g · cm ⁻³ or less is particularly preferable.

When the density of the active material existing on the current collector exceeds the above range, the active material particles are destroyed, the initial irreversible capacity increases, and the non-aqueous electrolyte solution near the current collector / active material interface There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability. On the other hand, below the above range, the conductivity between the active materials may be reduced, the battery resistance may be increased, and the capacity per unit volume may be reduced.

<2-1-3-3. Composition, physical properties, and preparation method of negative electrode using carbonaceous material and metal compound-based material>
As the negative electrode active material, a metal compound material and the carbonaceous material may be contained. Here, the negative active material containing a metal compound-based material and a carbonaceous material is a simple metal or alloy that forms a lithium alloy, or a compound such as an oxide, carbide, nitride, silicide, or sulfide thereof. Any of them may be a mixture in which carbonaceous materials are mixed in the form of particles independent from each other, or a single metal or alloy forming a lithium alloy, or oxides, carbides, nitrides, silicides, sulfides thereof. A complex in which a compound such as is present on the surface or inside of a carbonaceous material may be used. In the present specification, the composite is not particularly limited as long as it includes a metal compound-based material and a carbonaceous material, but preferably the metal compound-based material and the carbonaceous material are physically and / or chemically. It is united by dynamic coupling. As a more preferable form, the metal compound-based material and the carbonaceous material are in a state where each solid component is dispersed to such an extent that they are present at least on the surface of the composite and in the bulk. It is a form in which a carbonaceous material is present for integration by mechanical and / or chemical bonding.

In such a form, the surface of the particle is observed with a scanning electron microscope, the particle is embedded in a resin to produce a thin section of the resin, and the particle cross section is cut out, or the coating film made of particles is formed with a cross section polisher. After the particle cross section is cut out, it can be observed by an observation method such as a particle cross section observation with a scanning electron microscope.
The content ratio of the metal compound material to the total of the negative electrode active material containing the metal compound material and the carbonaceous material is not particularly limited, but is usually 0.1% by mass or more, preferably 1% by mass or more, and more preferably. Is 1.5% by mass or more, more preferably 2% by mass or more, particularly preferably 3% by mass or more, and usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, 30% by weight or less, particularly preferably 25% by weight
Hereinafter, it is most preferably 15% by mass or less. This range is preferable in that a sufficient capacity can be obtained.

About the carbonaceous material used for the negative electrode active material containing a metal compound type material and a carbonaceous material, it is preferable to satisfy the requirements described in <2-3-2>. Moreover, it is desirable that the metal compound material satisfy the following.
As the single metal or alloy forming the lithium alloy, any conventionally known one can be used, but in terms of capacity and cycle life, the single metal forming the lithium alloy is:
For example, Fe, Co, Sb, Bi, Pb, Ni, Ag, Si, Sn, Al, Zr, Cr,
A metal selected from the group consisting of V, Mn, Nb, Mo, Cu, Zn, Ge, In, Ti and the like or a compound thereof is preferable. Further, as an alloy forming a lithium alloy, Si, Sn, A
A metal selected from the group consisting of s, Sb, Al, Zn and W or a compound thereof is preferable.

A single metal or alloy that forms a lithium alloy, or a compound such as an oxide, carbide, nitride, silicide, sulfide, etc. is a metal oxide, metal carbide, metal nitride, metal silicide,
Examples thereof include metal sulfides. Moreover, you may use the alloy which consists of 2 or more types of metals. Among these, Si or Si compound is preferable in terms of increasing capacity. In this specification, Si or Si
The compounds are generically called Si compounds. Specific examples of the Si compound include SiO _x , SiN _x , SiC _x , and SiZ _x O _y (Z is C or N), preferably SiOx. . The value of x in the above general formula is not particularly limited,
Usually, 0 ≦ x <2. The SiO _x is composed of silicon dioxide (SiO ₂ ) and metal silicon (S
and i) as raw materials. SiO _x has a larger theoretical capacity than graphite, and amorphous Si or nano-sized Si crystals are easy for alkali ions such as lithium ions to enter and exit, so that a high capacity can be obtained.

The value of x in SiO _x is not particularly limited, but usually x is 0 ≦ x <2, preferably 0.2 or more, more preferably 0.4 or more, and further preferably 0.6 or more, Moreover, it is preferably 1.8 or less, more preferably 1.6 or less, and still more preferably 1.4 or less.
If it is this range, it becomes high capacity | capacitance and it becomes possible to reduce the irreversible capacity | capacitance by the coupling | bonding of Li and oxygen.

In order to confirm that the metal compound material is a metal material that can be alloyed with lithium, identification of the metal particle phase by X-ray diffraction, observation of the particle structure by an electron microscope, elemental analysis, fluorescence Elemental analysis by X-rays can be mentioned.
The volume-based average particle diameter (median diameter d50) of the metal compound-based material is not particularly limited, but is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, from the viewpoint of cycle life. Preferably it is 0.3 μm or more, and usually 10 μm
m or less, preferably 9 μm or less, more preferably 8 μm or less. Average particle diameter (d50
) Is within the above range, the volume expansion associated with charge / discharge is reduced, while maintaining the charge / discharge capacity,
Good cycle characteristics can be obtained.

The average particle diameter (d50) is determined by a laser diffraction / scattering particle size distribution measuring method or the like.
The specific surface area of the metal compound material used for the negative electrode active material containing the metal compound material and the carbonaceous material is not particularly limited by the BET method, but is usually 0.5 m ² / g or more, preferably 1 m ² / g or more. Moreover, it is 60 m < ² > / g or less normally, Preferably it is 40 m < ² > / g. Li
When the specific surface area of the metal particles that can be alloyed with the BET method is within the above range, the charge / discharge efficiency and discharge capacity of the battery are high, lithium can be taken in and out at high speed charge / discharge, and the rate characteristics are excellent.

The amount of oxygen contained in the metal compound material used in the negative electrode active material containing the metal compound material and the carbonaceous material is not particularly limited, but is usually 0.01% by mass or more, preferably 0.05% by mass.
In addition, it is usually 8% by mass or less, preferably 5% by mass or less. The oxygen distribution state in the particle may exist near the surface, may exist inside the particle, or may exist uniformly within the particle, but is preferably present near the surface. It is preferable for the oxygen content of the metal compound-based material to be in the above-mentioned range because the volume expansion associated with charge / discharge is suppressed due to strong bonding between Si and O and the cycle characteristics are excellent.
Moreover, about the negative electrode preparation of the metal compound type material used for the negative electrode active material containing a metal compound type material and a carbonaceous material, the thing as described in said <2-3-1> carbonaceous material can be used.

<2-1-3-4. Lithium-containing metal composite oxide material>
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, but lithium-containing composite metal oxide materials containing titanium are preferable, and lithium and titanium composite oxidation (Hereinafter "lithium titanium composite oxide")
May be abbreviated. Is particularly preferred. 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 lithium ion non-aqueous electrolyte secondary battery because the output resistance of the secondary battery is greatly reduced.

In addition, lithium and titanium of the lithium titanium composite oxide are other metal elements such as Na.
Also preferable are those substituted with at least one element selected from the group consisting of K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn and Nb.
As a lithium titanium composite oxide preferable as the negative electrode active material, a lithium titanium composite oxide represented by the following general formula (5) can be given.
_{Li x Ti y M z O 4} (5)
(In the general formula (5), M is Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu.
Represents at least one element selected from the group consisting of Zn, and Nb. In addition, the general formula (5
), It is 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, and 0 ≦ z ≦ 1.6, the structure at the time of doping and dedoping of lithium ions is stable This is preferable. )

<2-1-3-5. Structure, physical properties and preparation method of negative electrode>
For the negative electrode containing the active material, the electrode forming method, and the current collector, a known technical configuration can be adopted, and any one or a plurality of items (i) to (vi) shown below can be adopted. It is desirable to satisfy

(I) Negative electrode production Any known method can be used for the production of the negative electrode as long as the effects of the present invention are not significantly limited. For example, a negative electrode active material is added with a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to form a slurry-like negative electrode forming material, which is applied to a current collector, dried and then pressed. Thus, a negative electrode active material layer can be formed.

(Ii) 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 is 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 these, 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.

(Iii) Ratio of thickness of current collector and negative electrode active material layer The ratio of thickness of current collector and negative electrode active material layer is not particularly limited, but “(one side just before the non-aqueous electrolyte injection step) Negative electrode active material layer thickness) / (current collector thickness) "is preferably 150 or less, more preferably 20 or less, particularly preferably 10 or less, and more preferably 0.1 or more,
0.4 or more is more preferable, and 1 or more is particularly preferable.
If 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 of the secondary battery. Also, below the above range,
The volume ratio of the current collector to the negative electrode active material may increase, and the capacity of the secondary battery may decrease.

(Iv) Electrode density The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, and the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more. .2g · ^{cm -3} or more preferably, 1.3 g · ^{cm -3} or more, and also preferably 4g · ^{cm -3} or less, more preferably 3 g · ^{cm -3} or less, 2.5 g · cm ^{- 3} or less is more preferable and 1.7 or less.
Particularly preferred is g · cm ⁻³ or less. If the density of the negative electrode active material present on the current collector is within the above range, the negative electrode active material particles are less likely to be destroyed, an increase in the initial irreversible capacity of the secondary battery,
It becomes easy to prevent deterioration of high current density charge / discharge characteristics due to a decrease in permeability of the non-aqueous electrolyte near the current collector / negative electrode active material interface. Further, the conductivity between the negative electrode active materials can be secured, and the capacity per unit volume can be earned without increasing the battery resistance.

(V) Binder, solvent, etc. The slurry for forming the negative electrode active material layer is usually prepared by adding a mixture of a binder (binder), a thickener, etc. to a solvent to the negative electrode active material. The
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.

Specific examples thereof include polyethylene, polypropylene, polyethylene terephthalate,
Resin polymers such as polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose;
SBR (styrene butadiene rubber), isoprene rubber, butadiene rubber, fluoro rubber,
Rubbery polymers such as NBR (acrylonitrile butadiene rubber) and 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;
Polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride,
Fluoropolymers such as polytetrafluoroethylene / ethylene copolymer;
Examples thereof include polymer compositions 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 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-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, etc. Can be mentioned.

In particular, when an aqueous solvent is used, it is preferable to add a dispersant or the like in addition to the thickener and slurry it 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.
The ratio of the binder to 100 parts by mass of the negative electrode active material is preferably 0.1 parts by mass or more,
0.5 parts by mass or more is more preferable, 0.6 parts by mass or more is more preferable, 20 parts by mass or less is preferable, 15 parts by mass or less is more preferable, 10 parts by mass or less is further preferable, and 8 parts by mass or less is preferable. Particularly preferred. When the ratio of the binder to the negative electrode active material is within the above range, the ratio of the binder that does not contribute to the battery capacity does not increase, so that the battery capacity is hardly lowered. Furthermore, the strength of the negative electrode is hardly lowered.

In particular, when the slurry as the negative electrode forming material contains a rubbery polymer typified by SBR as a main component, the ratio of the binder to 100 parts by mass of the negative electrode active material is preferably 0.1 parts by mass or more. More preferably 5 parts by mass or more, more preferably 0.6 parts by mass or more, more preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less.

When the slurry contains a fluorine-based polymer typified by polyvinylidene fluoride as a main component, the ratio of the binder to 100 parts by mass of the negative electrode active material is preferably 1 part by mass or more and more preferably 2 parts by mass or more. Preferably, 3 parts by mass or more is more preferable, 15 parts by mass or less is preferable, 10 parts by mass or less is more preferable, and 8 parts by mass or less is still more preferable.
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. Even if these are used alone,
Two or more kinds may be used in any combination and ratio.

When using a thickener, the ratio of the thickener to 100 parts by mass of the negative electrode active material is usually 0.1 parts by mass or more, preferably 0.5 parts by mass or more, and more preferably 0.6 parts by mass or more. Moreover, the said ratio is 5 mass parts or less normally, 3 mass parts or less are preferable, and 2 mass parts or less are more preferable. When the ratio of the thickener to the negative electrode active material is within the above range, the coating property of the slurry becomes good. Furthermore, the ratio of the negative electrode active material in the negative electrode active material layer is also moderate, and the problem of a decrease in battery capacity and a problem of an increase in resistance between the negative electrode active materials are less likely to occur.

(Vi) Area of Negative Electrode Plate The area of the negative electrode plate is not particularly limited, but it is preferably designed to be slightly larger than the opposing positive electrode plate so that the positive electrode plate does not protrude from the negative electrode plate. In addition, from the viewpoint of suppressing deterioration due to cycle life and high temperature storage when charging and discharging of the secondary battery are repeated,
It is preferable to make the area as close as possible to the positive electrode as much as possible because the characteristics are improved by increasing the proportion of electrodes that work more uniformly and effectively. In particular, when the secondary battery is used with a large current, the design of the area of the negative electrode plate is important.

<2-1-4. Positive electrode>
The positive electrode used for the non-aqueous electrolyte secondary battery of the present invention will be described below.
<2-1-4-1. Cathode active material>
The positive electrode active material used for the positive electrode will be described below.
(1) Composition The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release metal ions. For example, a material that can electrochemically occlude and release lithium ions is preferable.
Substances containing lithium and at least one transition metal are preferred. Specific examples include lithium transition metal composite oxides, lithium-containing transition metal phosphate compounds, lithium-containing transition metal silicate compounds, and lithium-containing transition metal borate compounds.

As the transition metal of the lithium transition metal composite oxide, V, Ti, Cr, Mn, Fe, C
o, Ni, Cu and the like are preferable, and specific examples of the composite oxide include lithium-cobalt composite oxides such as LiCoO ₂ , lithium-nickel composite oxides such as LiNiO ₂ , and LiMn.
Li, manganese composite oxides such as O ₂ , LiMn ₂ O ₄ , Li ₂ MnO _4, etc., and some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Al, Ti, V, Cr, M
n, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn
, W and the like substituted with other metals.

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 , LiMn ₂ O ₄ , LiMn _1.8 Al _0.2 O ₄ , Li _1.1 Mn _1.9 Al _0.1
Examples thereof include O ₄ and LiMn _1.5 Ni _0.5 O ₄ .
Among these, composite oxides containing lithium, nickel, and cobalt are more preferable. This is because a composite oxide containing cobalt and nickel can have a large capacity when used at the same potential.

On the other hand, cobalt is an expensive metal with a small amount of resources, and since the amount of active material used is large in large batteries that require high capacity such as for automobiles, it is not preferable in terms of cost, so it is cheaper. It is also desirable to use manganese as the transition metal as the main component. That is, lithium-nickel-cobalt-manganese composite oxide is particularly preferable. Among these, from the viewpoint of highly satisfying the balance between cost and capacity, lithium-nickel-cobalt-manganese composite oxides in which the amount of cobalt used is reduced and the amount of nickel used is increased are most preferable.

As an example of a preferable positive electrode, lithium, nickel, cobalt, represented by the following composition formula (a)
Manganese composite oxide is mentioned.
Li _a2 Ni _b2 Co _c2 M _d2 O ₂ (a)
(In the above formula (a), a2, b2, c2 and d2 are 0.9 ≦ a2 ≦ 1.10, 0.50 ≦
b2 ≦ 0.98, 0.01 ≦ c2 <0.50, 0.01 ≦ d2 <0.50
b2 + c2 + d2 = 1 is satisfied. M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er. )
Specific examples of the lithium / nickel / cobalt / manganese composite oxide represented by the composition formula (a) include LiNi _0.5 Co _0.2 Mn _0.3 O ₂ and LiNi _0.6 Co _0.2 Mn.
Examples include _0.2 O ₂ and LiNi _0.8 Co _0.1 Mn _0.1 O ₂ .

In view of stability as a compound and procurement cost due to ease of production, a lithium manganese composite oxide having a spinel structure is also preferable. That is, among the above specific examples, LiMn ₂ O ₄ , LiMn _1.8 Al _0.2 O ₄ , Li _1.1 Mn _1.9 Al _0.1 O ₄
, LiMn _1.5 Ni _0.5 O _{4 and the} like can also be mentioned as preferred specific examples.
As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, F
e, Co, Ni, Cu and the like are preferable, and specific examples of the phosphoric acid compound include, for example, LiF.
Iron phosphates such as ePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ , LiFeP ₂ O ₇ , LiCoPO ₄
Cobalt phosphates such as LiMnPO ₄ , manganese phosphates such as LiMnPO 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,
Examples include those substituted with other metals such as Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W.

Examples of the transition metal of the lithium-containing transition metal silicate compound include V, Ti, Cr, Mn,
Fe, Co, Ni, Cu and the like are preferable. Specific examples of the silicate compound include, for example, L
Iron, silicic acid such as i ₂ FeSiO _4, cobalt silicate such as Li ₂ CoSiO ₄ , and some of transition metal atoms that are main components of these lithium transition metal silicate compounds are Al, Ti, V, Cr
, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo,
Examples include those substituted with other metals such as Sn and W.

Examples of the transition metal of the lithium-containing transition metal borate compound include V, Ti, Cr, Mn,
Fe, Co, Ni, Cu and the like are preferable, and specific examples of the boric acid compound include, for example, L
Iron borates such as iFeBO _3, cobalt borates such as LiCoBO ₃ , and some of transition metal atoms that are the main components of these lithium transition metal boric acid compounds are Al, Ti, V, Cr, Mn,
Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W
And the like substituted with other metals.

(2) Method for producing positive electrode active material The method for producing the positive electrode active material is not particularly limited as long as it does not exceed the gist of the present invention.
There are several methods, and a general method is used as a method for producing the inorganic compound.
In particular, various methods are conceivable for producing a spherical or elliptical active material. For example, transition metal source materials such as transition metal nitrates and sulfates, and source materials of other elements as necessary. Is dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring to produce and recover a spherical precursor, which is dried as necessary, and then LiOH, Li ₂ CO ₃ , Li
Examples thereof include a method of obtaining an active material by adding a Li source such as NO ₃ and baking at a high temperature.

In addition, as an example of another method, transition metal raw materials such as transition metal nitrates, sulfates, hydroxides, oxides and the like, and if necessary, raw materials of other elements are dissolved or pulverized and dispersed in a solvent such as water. do it,
This is dried and molded with a spray dryer or the like to form a spherical or elliptical precursor,
Examples include a method of obtaining an active material by adding a Li source such as iOH, Li ₂ CO ₃ , or LiNO ₃ and baking at a high temperature.

Examples of other methods include transition metal source materials such as transition metal nitrates, sulfates, hydroxides, oxides, Li sources such as LiOH, Li ₂ CO ₃ , LiNO ₃ , and other elements as necessary. The raw material is dissolved or pulverized and dispersed in a solvent such as water, and is then dried by a spray dryer or the like to form a spherical or elliptical precursor, which is fired at a high temperature to obtain an active material. Can be mentioned.

<2-1-4-2. Positive electrode structure and fabrication method>
Below, the structure of the positive electrode used for this invention and its preparation method are demonstrated.
(Production method of positive electrode)
The positive electrode is produced by forming a positive electrode active material layer containing positive electrode active material particles and a binder on a current collector. The production of the positive electrode using the positive electrode active material can be produced by any known method. For example, 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 are pressure-bonded to the positive electrode current collector, or these materials are dissolved in a liquid medium Alternatively, a positive electrode can be obtained by forming a positive electrode active material layer on the current collector by dispersing and applying it as a slurry to a positive electrode current collector and drying it.

The content of the positive electrode active material in the positive electrode active material layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and preferably 99.9% by mass or less. Yes, 99 mass% or less is more preferable. When the content of the positive electrode active material is within the above range, a sufficient electric capacity can be secured. Furthermore, the strength of the positive electrode is sufficient. In addition, the positive electrode active material powder in this invention may be used individually by 1 type, and may use together 2 or more types of a different composition or different powder physical properties by arbitrary combinations and ratios. When two or more active materials are used in combination, the composite oxide containing lithium and manganese is preferably used as a powder component. As described above, cobalt or nickel is an expensive metal with a small amount of resources, and is not preferable in terms of cost because the amount of active material used is large in large batteries that require high capacity such as for automobiles. Therefore, it is desirable to use manganese as a main component as a cheaper transition metal.

(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 carbonaceous 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 content of the conductive material in the positive electrode active material layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 1% by mass or more, and preferably 50% by mass or less. 30 mass% or less is more preferable, and 15 mass% or less is still more preferable. When the content is within the above range, sufficient conductivity can be secured. Furthermore, it is easy to prevent a decrease in battery capacity.

(binder)
The binder used for manufacturing the positive electrode active material layer 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 when manufacturing the electrode.
In the case of producing a positive electrode by a coating method, the binder is not particularly limited as long as it is a material that can be dissolved or dispersed in a liquid medium used at the time of electrode production. Specific examples thereof include polyethylene, polypropylene, polyethylene terephthalate, and polymethyl. Resin polymers such as methacrylate, aromatic polyamide, cellulose, nitrocellulose;
SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber),
Rubbery polymers such as fluoro rubber, isoprene rubber, butadiene rubber, ethylene / propylene rubber;
Styrene / butadiene / styrene block copolymer or its hydrogenated product, 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;
Examples thereof include polymer compositions 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 binder content in the positive electrode active material layer is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and preferably 80% by mass or less. 60 mass% or less is more preferable, 40 mass% or less is still more preferable, and 10 mass% or less is especially preferable. When the ratio of the binder is within the above range, the positive electrode active material can be sufficiently retained, and the mechanical strength of the positive electrode can be secured, so that battery performance such as cycle characteristics is improved. Furthermore, it also leads to avoiding a decrease in battery capacity and conductivity.

(Liquid medium)
The liquid medium used for the preparation of the slurry for forming the positive electrode active material layer includes a positive electrode active material, a conductive material, a binder, and a solvent capable of dissolving or dispersing a thickener used as necessary. If it exists, there is no restriction | limiting in particular in the kind, You may use either an aqueous solvent or an organic solvent.

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, methylnaphthalene;
Heterocyclic compounds such as quinoline and pyridine;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone;
Esters such as methyl acetate and methyl acrylate;
Amines such as diethylenetriamine and N, N-dimethylaminopropylamine;
Ethers such as diethyl ether and tetrahydrofuran (THF);
Amides such as N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide;
Examples include aprotic polar solvents such as hexamethylphosphalamide and dimethyl sulfoxide. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

(Thickener)
When an aqueous medium is used as the liquid medium for forming the slurry, it is preferable to form 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 limited as long as the effect of the present invention is not significantly limited. Specifically, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof Etc. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

When using a thickener, the ratio of the thickener to the total mass of the positive electrode active material and the thickener is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, 0.6% by mass
The above is more preferable, and preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 2% by mass or less. Within the above range, the coating property of the slurry becomes good, and further, the ratio of the active material in the positive electrode active material layer becomes sufficient. It becomes easy to avoid the problem that the resistance increases.

(Consolidation)
In order to increase the packing density of the positive electrode active material, the positive electrode active material layer obtained by applying the slurry to the current collector and drying is preferably consolidated by a hand press, a roller press or the like. The density of the positive electrode active material layer is preferably 1 g · cm ⁻³ or more, more preferably 1.5 g · cm ⁻³ or more, particularly preferably 2 g · cm ⁻³ or more, and preferably 4 g · cm ⁻³ or less. 3.5 g · cm ⁻³ or less is more preferable, and 3 g · cm ⁻³ or less is particularly preferable.
When the density of the positive electrode active material layer is within the above range, charging / discharging at a high current density of the secondary battery, in particular, does not decrease the permeability of the non-aqueous electrolyte solution to the vicinity of the current collector / active material interface. Good characteristics. Furthermore, the electrical conductivity between the active materials is difficult to decrease, and the battery resistance is difficult to increase.

(Current collector)
There is no restriction | limiting in particular as a material of a positive electrode electrical power collector, A well-known thing can be used arbitrarily.
Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbonaceous 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, foam metal, etc. A carbon 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.
The thickness of the current collector is arbitrary, but is preferably 1 μm or more, more preferably 3 μm or more, further preferably 5 μm or more, and preferably 1 mm or less, more preferably 100 μm or less, and further preferably 50 μm or less. preferable. When the thickness of the current collector is within the above range, sufficient strength required for the current collector can be ensured. Furthermore, the handleability is also improved.

The thickness ratio between the current collector and the positive electrode active material layer is not particularly limited, but (active material layer thickness on one side immediately before non-aqueous electrolyte injection) / (current collector thickness) is preferably 150 or less, more preferably 20 or less, particularly preferably 10 or less, preferably 0.1 or more, more preferably 0.4 or more, and particularly preferably 1 or more.
When the ratio of the thickness of the current collector to the positive electrode active material layer is within the above range, the current collector is unlikely to generate heat due to Joule heat during high current density charge / discharge of the secondary battery. Furthermore, it becomes difficult for the volume ratio of the current collector to the positive electrode active material to increase, and a decrease in battery capacity can be prevented.

(Electrode area)
From the viewpoint of increasing the stability at high output and high temperature, the area of the positive electrode active material layer is preferably larger than the outer surface area of the battery outer case. Specifically, the total electrode area of the positive electrode with respect to the surface area of the exterior of the non-aqueous electrolyte secondary battery is preferably 20 times or more, 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.

(Discharge capacity)
When the non-aqueous electrolyte of the present invention is used, the electric capacity of the battery element housed in one battery exterior of the non-aqueous electrolyte secondary battery (electric capacity when the battery is discharged from a fully charged state to a discharged state) ) Is 1 ampere hour (Ah) or more, since the effect of improving the low temperature discharge characteristics is increased. Therefore, the positive electrode plate has a fully charged discharge capacity, preferably 3 Ah (ampere hour), more preferably 4 Ah or more, and preferably 20 Ah or less,
More preferably, it is designed to be 10 Ah or less.

Within the above range, the voltage drop due to the electrode reaction resistance does not become excessive when a large current is taken out, and the deterioration of the power efficiency can be prevented. Furthermore, the temperature distribution due to the internal heat generation of the battery during pulse charge / discharge does not become too large, the durability of repeated charge / discharge is inferior, and the heat dissipation efficiency is poor against sudden heat generation during abnormalities such as overcharge and internal short circuit. The phenomenon of becoming can be avoided.

(Thickness of positive plate)
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity, high output, and high rate characteristics,
The thickness of the positive electrode active material layer minus the thickness of the current collector is preferably 10 μm or more, more preferably 20 μm or more, more preferably 200 μm or less, and 100 μm with respect to one surface of the current collector.
m or less is more preferable.

<2-1-5. Separator>
In the non-aqueous electrolyte secondary battery of the present invention, a separator is usually 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.
There is no restriction | limiting in particular about the material and shape of a separator, As long as the effect of this invention is not impaired remarkably, a well-known thing can be employ | adopted arbitrarily. Among them, a resin, glass fiber, inorganic material, etc. formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention is used, and a porous sheet or a nonwoven fabric-like material having excellent liquid retention properties is used. Is preferred.

As materials for the resin and glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, aramid resins, polytetrafluoroethylene, polyethersulfone, glass filters and the like can be used. Of these, glass filters and polyolefins are preferred, and polyolefins are more preferred. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The thickness of the separator is arbitrary, but is preferably 1 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, and preferably 50 μm or less,
More preferably, it is not more than μm, and more preferably not more than 30 μm. When the thickness of the separator is within the above range, the insulation and mechanical strength are good. Furthermore, the battery performance such as rate characteristics can be prevented from being lowered, and the energy density of the non-aqueous electrolyte secondary battery as a whole can be prevented from being 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 preferably 20% or more, more preferably 35% or more, and further 45% or more. Preferably, it is 90% or less, more preferably 85% or less, and further preferably 75% or less. When the porosity is within the above range, the membrane resistance does not increase excessively, and deterioration of the rate characteristics of the secondary battery can be suppressed. Furthermore, the mechanical strength of the separator becomes appropriate, and the deterioration of the insulation can be suppressed.

The average pore diameter of the separator is also arbitrary, but is preferably 0.5 μm or less.
It is more preferably 2 μm or less, and preferably 0.05 μm or more. When the average pore diameter is within the above range, short circuit is difficult to occur. Furthermore, the membrane resistance does not increase too much, and the deterioration of the rate characteristics of the secondary battery can be prevented.
On the other hand, as the inorganic material, 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. Things are used.

As a form of the separator, a thin film shape such as a nonwoven fabric, a woven fabric, or a microporous film is used. A thin-film separator having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm is 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 on both surfaces of the positive electrode using alumina particles having a 90% particle size of less than 1 μm and using a fluororesin as a binder.

<2-1-6. Battery design>
(Electrode group)
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed via the separator.
Any of those having a structure in which the positive electrode plate and the negative electrode plate described above are spirally wound through the separator described above may be used. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is preferably 40% or more, more preferably 50% or more, and preferably 9%.
5% or less, more preferably 90% or less. When the electrode group occupancy is within the above range, the battery capacity is hardly reduced. In addition, since a moderate gap space can be secured, the internal pressure rises as the member expands or the vapor pressure of the liquid component of the non-aqueous electrolyte increases due to the high temperature of the battery. Various characteristics such as charge / discharge repeatability and high-temperature storage characteristics can be reduced, and further, it is possible to avoid a case where the gas release valve that releases the internal pressure to the outside operates.

(Current collection structure)
The current collecting structure is not particularly limited, but in order to more effectively realize the improvement of the discharge characteristics by the non-aqueous electrolyte solution of the present invention, it is necessary to make the structure to reduce the resistance of the wiring part and the joint part. 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 laminated structure described above, 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 reduce the resistance by providing a plurality of terminals in the electrode. 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.

(Protective element)
As a protective element, PTC (Posit) increases in resistance when abnormal heat generation or excessive current flows
Examples thereof include a thermistor, a thermal fuse, and a valve (current cutoff valve) that cuts off a current flowing in the circuit due to a sudden rise in battery internal pressure or internal temperature when abnormal heat is generated. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable to design a battery that does not cause abnormal heat generation or thermal runaway without a protective element.

(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 (exterior case). There is no restriction | limiting in this exterior body, A well-known thing can be arbitrarily employ | adopted unless the effect of this invention is impaired remarkably.
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 or an aluminum alloy, a magnesium alloy, nickel, titanium, or a metal, 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 the outer case using the above metals, the metal is welded to each other by laser welding, resistance welding, ultrasonic welding, or a sealed sealing structure, or a caulking structure using the above metals via a resin gasket To do. 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 a resin layer is heat-sealed through a current collecting terminal to form a sealed structure, a metal and a resin are joined, so that a resin having a polar group or a modified group having a polar group introduced as an intervening resin is used. Resins are preferably used.
The shape of the outer case 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.

<2-2. Non-aqueous electrolyte primary battery>
A material capable of occluding metal ions is used for the positive electrode, and a material capable of releasing metal ions is used for the negative electrode. As the positive electrode material, transition metal oxides such as graphite fluoride and manganese dioxide are preferable. The negative electrode material is preferably a simple metal such as zinc or lithium. As the non-aqueous electrolyte, the above-described non-aqueous electrolyte of the present invention is used.

<2-3. Metal Ion Capacitor>
A material capable of forming an electric double layer is used for the positive electrode, and a material capable of inserting and extracting metal ions is used for the negative electrode. Activated carbon is preferred as the positive electrode material. Moreover, as a negative electrode material, a carbonaceous material is preferable. As the non-aqueous electrolyte, the above-described non-aqueous electrolyte of the present invention is used.

<2-4. Electric Double Layer Capacitor>
A material capable of forming an electric double layer is used for the electrode. Activated carbon is preferable as the electrode material.
As the non-aqueous electrolyte, the above-described non-aqueous electrolyte of the present invention is used.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples, unless the summary is exceeded.
In addition, the compound a used as a structural component of a non-aqueous electrolyte solution in an Example and a comparative example is shown below.

<< Example 1-1, Comparative Example 1-1 >>
[Preparation of non-aqueous electrolyte secondary battery]
<Preparation of non-aqueous electrolyte solution>
[Example 1-1]
Under a dry argon atmosphere, LiPF ₆ sufficiently dried to a mixture of ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate (volume ratio 2: 4: 4) was added to 1.1.
It is dissolved at a concentration of 5 mol / L (as a concentration in the non-aqueous electrolyte solution), 1% by mass of vinylene carbonate (as the concentration in the non-aqueous electrolyte solution), and 1% by mass of difluorophosphate (non-aqueous electrolyte solution). Compound A was dissolved in an amount of 0.25% by mass (as the concentration in the non-aqueous electrolyte solution) to prepare a non-aqueous electrolyte solution. Using this non-aqueous electrolyte, a non-aqueous electrolyte secondary battery was prepared by the following method, and the following evaluation was performed.

[Comparative Example 1-1]
A non-aqueous electrolyte secondary battery was prepared in the same manner as in Example 1-1 except that Compound A was not dissolved, and the following evaluation was performed.
<Preparation of positive electrode>
Lithium nickel manganese cobalt composite oxide (LiNi _0.6 M
n _0.2 Co _0.2 O ₂ ) 90 parts by mass, 7 parts by mass of carbon black as a conductive material, 3 parts by mass of polyvinylidene fluoride (PVdF) as a binder, and N-methyl-2- After mixing and slurrying in pyrrolidone, this was uniformly coated on both sides of an aluminum foil having a thickness of 15 μm and dried, and then roll-pressed to obtain a positive electrode.

<Production of negative electrode>
Aqueous dispersion of sodium carboxymethylcellulose as a thickener (concentration of sodium carboxymethylcellulose 1 mass%) 10 in 98 parts by mass of graphite powder
0 part by mass and 2 parts by mass of an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber 50% by mass) as a binder were added and mixed with a disperser to form a slurry. The obtained slurry was uniformly applied to a 10 μm thick copper foil, dried, and roll-pressed to obtain a negative electrode.

<Manufacture of non-aqueous electrolyte secondary battery>
The positive electrode, the negative electrode, and the polyolefin separator were laminated in the order of the negative electrode, the separator, the positive electrode, the separator, and the negative electrode. The battery element thus obtained was wrapped with an aluminum laminate film, and after injecting the non-aqueous electrolytes of the above-described Examples and Comparative Examples, vacuum sealing was performed to produce a sheet-like non-aqueous electrolyte secondary battery.

[Evaluation of non-aqueous electrolyte secondary battery]
-Initial charging / discharging The secondary battery produced by said method is 0.05C (The electric current value which discharges the rated capacity by the discharge capacity of 1 hour rate in 1 hour is set to 1C in a 25 degreeC thermostat. ) 3.75
Constant current-constant voltage charging up to V (constant voltage charging was carried out until the current was reduced to 0.02C.
The same applies below. ) And discharged to 2.8 V at 0.2C. Subsequently, the battery was charged at a constant current-constant voltage to 4.3 V at 0.2 C, and then discharged to 2.8 V at 0.2 C. Subsequently, 4. at 0.2C.
After charging at a constant current-constant voltage to 3V, the battery was discharged to 2.8V at 0.2C. In this way, the non-aqueous electrolyte secondary battery was stabilized.

-Initial volume measurement The volume at 25 degrees C of the stabilized non-aqueous electrolyte secondary battery was measured by the Archimedes method using ethanol. This volume value was taken as the initial volume.
60 ° C. storage test A fully charged non-aqueous electrolyte secondary battery charged at a constant current-constant voltage up to 4.3 V at 0.2 C in a constant temperature bath at 25 ° C. was stored in a constant temperature bath at 60 ° C. for 28 days. .

-Volume measurement after storage test After returning the non-aqueous electrolyte secondary battery after the storage test to 25 ° C, it was measured by Archimedes method using ethanol. This volume value was taken as the volume after the storage test.
In Table 1 below,
The swelling during storage calculated by (volume after storage test) − (initial volume) is shown normalized by the value of Comparative Example 1-1.

As is apparent from Table 1, the use of the electrolytic solution of the present invention shows a remarkable effect that can reduce swelling during storage.

According to the non-aqueous electrolyte solution of the present invention, it is possible to provide an electricity storage device with little characteristic deterioration, and thus the electrolyte solution can be suitably used in all fields such as electronic equipment in which the electricity storage device is used.
The use of the non-aqueous electrolyte of the present invention and the electricity storage device using the same is not particularly limited, and can be used for various known uses. Specific examples of applications include laptop computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, mobile audio players, small video cameras, LCD TVs, handy cleaners, transceivers, electronic notebooks, calculators, and memories. Card, portable tape recorder, radio, backup power supply, automobile, motorcycle, motorbike, bicycle, lighting equipment, toy, game machine,
A watch, a power tool, a strobe, a camera, a lithium ion capacitor, and the like can be given.

Claims (13)

A non-aqueous electrolyte in which an electrolyte is dissolved in a non-aqueous solvent,
A non-aqueous electrolyte containing a cyclic carbonate and a compound represented by the following general formula (1).

(In the formula ^(1), R 1 ~R ^3, which may be the being the same or different, is an organic group having 1 to 20 carbon atoms that may have a substituent. However, R ¹ at least one of to R ³ is a carbon - carbon unsaturated bond or a cyano group). 2. The non-aqueous electrolyte solution according to claim 1, wherein the content of the cyclic carbonate is less than four times the content of the electrolyte. 2. In the general formula (1), R ^{1 to} R ³ may be the same as or different from each other, and are an organic group having 1 to 10 carbon atoms that may have a substituent. Or the non-aqueous electrolyte solution of 2. 4. The non-aqueous electrolyte solution according to claim 1, wherein in the general formula (1), at least one of R ^{1 to} R ³ is an organic group having a carbon-carbon unsaturated bond. 5. The non-aqueous system according to any one of claims 1 to 4, wherein, in the general formula (1), the organic group having a carbon-carbon unsaturated bond is a group selected from the group consisting of an allyl group and a methallyl group. Electrolytic solution. The compound having the structure represented by the general formula (1) is added to the nonaqueous electrolyte solution in an amount of 0.
The nonaqueous electrolytic solution according to any one of claims 1 to 5, which is contained in an amount of from 01% by mass to 10.0% by mass. Furthermore, the non-aqueous electrolyte solution as described in any one of Claim 1 thru | or 6 containing the at least 1 sort (s) of compound chosen from the group which consists of a difluorophosphate, a fluorosulfate, and a dicarboxylic acid complex salt. Wherein the electrolyte is LiPF _6, a nonaqueous electrolyte solution according to any one of claims 1 to 7. Furthermore, the non-aqueous electrolyte solution as described in any one of Claims 1 thru | or 8 containing vinylene carbonate. Furthermore, the non-aqueous electrolyte solution as described in any one of Claims 1 thru | or 9 containing a fluoro fluoro lithium salt. A power storage device comprising a plurality of electrodes capable of inserting and extracting metal ions and a non-aqueous electrolyte solution,
The non-aqueous electrolyte solution is the non-aqueous electrolyte solution according to any one of claims 1 to 10.
Power storage device. The plurality of electrodes capable of occluding and releasing metal ions are a positive electrode capable of occluding and releasing metal ions and a negative electrode capable of occluding and releasing metal ions, and the negative electrode is a carbonaceous material or a material containing silicon. The electricity storage device according to claim 11, comprising: The plurality of electrodes capable of occluding and releasing metal ions are a positive electrode capable of occluding and releasing metal ions and a negative electrode capable of occluding and releasing metal ions, and the positive electrode is represented by the following composition formula (a): The electric storage device according to claim 11, comprising a transition metal oxide.
Li _a2 Ni _b2 Co _c2 M _d2 O ₂ (a)
(In the above formula (a), a2, b2, c2 and d2 are 0.90 ≦ a2 ≦ 1.10, 0.50.
≦ b2 ≦ 0.98, 0.01 ≦ c2 <0.50, 0.01 ≦ d2 <0.50 are shown, and b2 + c2 + d2 = 1 is satisfied. M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er. )