JP2020119855A - Nonaqueous electrolyte battery - Google Patents

Abstract

To provide a nonaqueous electrolyte battery which is arranged to have a satisfactory charge/discharge efficiency even after being charged and discharged repeatedly.SOLUTION: A nonaqueous electrolyte battery comprises a positive electrode, a negative electrode and a nonaqueous electrolyte. In the nonaqueous electrolyte battery, the negative electrode has a negative electrode active material including particles of Si or Si oxide, and a binder containing polyacrylic acid. The nonaqueous electrolyte contains difluorophosphate. The binder preferably contains sodium polyacrylate, and 1.2 wt.%-aqueous solution of the binder is preferably pH3 to pH7.SELECTED DRAWING: None

Description

The present invention relates to a non-aqueous electrolyte battery, specifically, a negative electrode including a negative electrode active material having a specific material and a binder having a specific material, and a non-aqueous electrolytic solution using a non-aqueous electrolytic solution containing a specific compound. Regarding batteries.

Non-aqueous electrolyte solution using non-aqueous electrolyte solution such as lithium secondary battery in a wide range of applications from so-called consumer power sources such as mobile phones and laptop computers to in-vehicle power sources for automobiles and large-scale stationary power sources. Batteries are in practical use.
For example, in a lithium non-aqueous electrolyte battery, cyclic carbonates such as ethylene carbonate and propylene carbonate, chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, cyclic carbonates such as γ-butyrolactone and γ-valerolactone. A non-aqueous electrolyte solution containing a non-aqueous solvent of a chain carboxylic acid ester such as acid esters, methyl acetate, ethyl acetate, and methyl propionate, and a solute (electrolyte) such as LiPF ₆ and LiBF ₄ is used.

In such a non-aqueous electrolyte battery, the reactivity varies depending on the composition of the non-aqueous electrolyte solution, and therefore the characteristics greatly change depending on the non-aqueous electrolyte solution. Various studies on non-aqueous solvents and electrolytes in non-aqueous electrolytes in order to improve battery characteristics such as load characteristics, cycle characteristics, and storage characteristics of energy devices and to enhance battery safety during overcharge. Has been done.
For example, Patent Document 1 discloses a technique for suppressing the decomposition of a non-aqueous electrolyte solution and improving the capacity retention rate (capacity remaining rate) after storage by using an electrolyte solution containing lithium difluorophosphate. There is.

On the other hand, in the practical application of non-aqueous electrolyte batteries, non-aqueous electrolyte batteries with high charge/discharge efficiency even after repeated charge/discharge have been developed, especially in automobile applications where the market is expected to grow in the future, along with improvements in battery characteristics. Required.

JP, 11-67270, A

The present invention has been made in view of such background art, and an object thereof is to increase the charge/discharge efficiency after repeated charge/discharge of a non-aqueous electrolyte battery.

The present inventor, as a result of intensive studies to solve the above problems, a negative electrode containing a negative electrode active material having a specific material and a binder having a specific material, and a non-aqueous electrolyte containing a specific compound are combined. It was found that high charging/discharging efficiency can be realized, and the present invention has been achieved.
That is, the present invention provides the specific modes and the like shown in [1] to [4] below.
[1] A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, wherein the negative electrode is Si.
Alternatively, a non-aqueous electrolyte battery having a negative electrode active material containing Si oxide particles and a binder containing polyacrylic acid, and the non-aqueous electrolyte containing difluorophosphate.
[2] The non-aqueous electrolyte battery according to [1], wherein the 1.2 wt% aqueous solution of the binder has a pH of 3 to 7.
[3] The non-aqueous electrolyte battery according to [1] or [2], wherein the binder contains sodium polyacrylate.
[4] The negative electrode active material further contains graphite particles, and the content of the Si or Si oxide particles relative to the total of the Si or Si oxide particles and the graphite particles is 0.1 to 20 mass. %, the non-aqueous electrolyte battery according to any one of [1] to [3].

According to the present invention, it is possible to obtain a non-aqueous electrolyte battery having high charge/discharge efficiency.

Hereinafter, embodiments of the present invention will be described in detail. The following embodiment is an example (representative example) of the embodiment of the present invention, and the present invention is not limited thereto. Further, the present invention can be implemented by being arbitrarily modified within the scope of the invention.

<1. Non-aqueous electrolyte>
<1-1. Difluorophosphate>
The non-aqueous electrolyte solution of the present invention is characterized by containing a difluorophosphate salt.
The counter cation of the difluorophosphate is not particularly limited, but includes lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR ¹³ R ¹⁴ R ¹⁵ R ¹⁶ (in the formula, R ^{13 to} R ¹⁶ Each independently represent a hydrogen atom or an organic group having 1 to 12 carbon atoms), and the like, and the like.

The organic group having 1 to 12 carbon atoms represented by R ^{13 to} R ¹⁶ of ammonium is not particularly limited, but is, for example, an alkyl group optionally substituted with a halogen atom, a halogen atom or an alkyl group. And an optionally substituted cycloalkyl group, an aryl group which may be substituted with a halogen atom or an alkyl group, a nitrogen atom-containing heterocyclic group which may have a substituent, and the like. Among them, R ^{13 to} R ¹⁶ are preferably each independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

Specific examples of the difluorophosphate include lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate, and the like, with lithium difluorophosphate being preferred.
As the difluorophosphate, one kind may be used alone, or two kinds or more may be used in optional combination and ratio.

The amount of the difluorophosphate salt is not particularly limited and is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.001% by mass or more, preferably 0% by mass in 100% by mass of the non-aqueous electrolyte solution. 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass.
Below, most preferably it is 1 mass% or less.
Within this range, the coefficient of liquid absorption into the negative electrode can be increased, and swelling of the non-aqueous electrolyte battery due to charge/discharge can be suitably suppressed.

<1-2. Electrolyte>
The non-aqueous electrolytic solution of the present invention usually contains an electrolyte, like a general non-aqueous electrolytic solution.
<1-2-1. Lithium salt>
A lithium salt is usually used as the electrolyte in the non-aqueous electrolyte solution according to the present invention.
The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any one can be used, and specific examples include the following.

For _{example, LiBF 4, LiClO 4, LiAlF} 4, LiSbF 6, LiTaF 6, L
Inorganic lithium salts such as iWF ₇ ; Lifluorophosphate lithium salts such as LiPF ₆ ; LiWOF
Lithium tungstate salts such as ₅ ; HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂
Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂
CO ₂ Li, CF ₃ CF ₂ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li and other carboxylic acid lithium salts; CH ₃ SO ₃ Li and other sulfonic acid lithium salts; LiN(FC
_{O 2) 2, LiN (FCO} ) (FSO 2), LiN (FSO 2) 2, LiN (FSO 2)
_{(CF 3 SO 2), LiN} (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane di sulfonyl _{imide, LiN (CF 3 SO 2)} (C 4 F 9 SO 2) lithium imide salts such _{as; LiC (FSO 2) 3,} LiC (CF 3 SO 2) 3, LiC (C 2 F 5 S
Lithium methide salts such as O ₂ ) ₃ ; lithium difluoro oxalato borate, lithium bis (oxalato) borate, lithium tetrafluoro oxalato phosphate, lithium difluoro bis (oxalato) phosphate, lithium tris (oxalato) phosphate, etc. Rat salts; Others, LiPF ₄ (CF ₃ ) ₂ , LiPF _{4
(C 2 F 5) 2,} LiPF 4 (CF 3 SO 2) 2, LiPF 4 (C 2 F 5 SO 2) 2, L
_{iBF 3 CF 3, LiBF 3 C} 2 F 5, LiBF 3 C 3 F 7, LiBF 2 (CF 3) 2,
LiBF ₂ (C ₂ F ₅ ) ₂ , LiBF ₂ (CF ₃ SO ₂ ) ₂ , LiBF ₂ (C ₂ F ₅ SO
₂ ) Fluorine-containing organic lithium salts such as ₂ ; and the like.

Charge/Discharge Rate From the viewpoint of further enhancing the effect of improving charge/discharge characteristics and impedance characteristics, an inorganic lithium salt, a lithium fluorophosphate salt, a lithium sulfonate salt, a lithium imide salt, or a lithium oxalate salt is preferably selected. ..
Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiN(FSO ₂ )
₂ , LiN(FSO ₂ )(CF ₃ SO ₂ ), LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F
₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiC(FSO ₂ ) ₃ , LiC
(CF ₃ SO ₂ ) ₃ , LiC(C ₂ F ₅ SO ₂ ) ₃ , lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate or lithium difluorobis(oxalato)phosphate, lithium Tris (
Oxalato)phosphate is preferable because it has the effect of improving low-temperature output characteristics, high-rate charge/discharge characteristics, impedance characteristics, high-temperature storage characteristics, cycle characteristics, and the like.
PF ₆ is preferred. The above electrolyte salts may be used alone or in combination of two or more.

The total concentration of these electrolytes in the non-aqueous electrolytic solution is not particularly limited as long as the viscosity of the desired electrolytic solution is obtained, but is usually 8% by mass or more based on the total amount of the non-aqueous electrolytic solution, preferably Is 8
． It is 5% by mass or more, more preferably 9% by mass or more, and usually 18% by mass or less, preferably 17% by mass or less, more preferably 16% by mass or less. When the total concentration of the electrolyte is within the above range, the electric conductivity becomes appropriate for the battery operation, so that sufficient output characteristics tend to be obtained.

<1-3. Non-aqueous solvent>
The non-aqueous electrolytic solution of the present invention usually contains, as a main component, a non-aqueous solvent capable of dissolving the above-mentioned electrolyte, as in a general non-aqueous electrolytic solution. The non-aqueous solvent used here is not particularly limited, and a known organic solvent can be used. Examples of the organic solvent include saturated cyclic carbonates, chain carbonates, ether compounds, sulfone compounds, and the like.
It is not particularly limited to these. These may be used alone or in combination of two or more.

<1-3-1. Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms, and a saturated cyclic carbonate having 2 to 3 carbon atoms is preferably used from the viewpoint of improving battery characteristics resulting from improvement in dissociation degree of lithium ions. ..
Examples of the saturated cyclic carbonate include ethylene carbonate, propylene carbonate, butylene carbonate and the like. Among them, ethylene carbonate or propylene carbonate is preferable, and ethylene carbonate which is difficult to be oxidized/reduced is more preferable. As the saturated cyclic carbonate, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.

Further, the content of the saturated cyclic carbonate is not particularly limited as long as the viscosity of the desired electrolytic solution is obtained, but the lower limit of the content when using one kind alone is the total amount of the solvent of the non-aqueous electrolytic solution. On the other hand, it is usually 3% by volume or more, preferably 5% by volume or more. By setting this range,
Avoiding a decrease in electrical conductivity resulting from a decrease in the dielectric constant of the non-aqueous electrolyte solution, the large current discharge characteristics of the non-aqueous electrolyte battery, the stability to the negative electrode, and the cycle characteristics can be easily made into a good range, and usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. Within this range, the oxidation/reduction resistance of the non-aqueous electrolyte solution is improved, and the stability during storage at high temperature tends to be improved.
The volume% in the present invention means the volume at 25°C and 1 atm.

<1-3-2. Chain carbonate>
As the chain carbonate, one having 3 to 7 carbon atoms is usually used, and in order to adjust the viscosity of the electrolytic solution in an appropriate range, a chain carbonate having 3 to 5 carbon atoms is preferably used.
Specifically, as the chain carbonate, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate,
Examples thereof include n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate and t-butyl ethyl carbonate.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethylmethyl carbonate or methyl-n-propyl carbonate is preferable, and dimethyl carbonate, diethyl carbonate or ethylmethyl carbonate is particularly preferable. is there.
Further, chain carbonates having a fluorine atom (hereinafter, "fluorinated chain carbonate"
May be abbreviated. ) Can also be preferably used. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, and preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or different carbons. Examples of the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, fluorinated diethyl carbonate derivatives and the like.

As the fluorinated dimethyl carbonate derivative, fluoromethyl methyl carbonate,
Difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (
Examples thereof include fluoromethyl)carbonate, bis(difluoro)methyl carbonate, bis(trifluoromethyl)carbonate and the like. Examples of the fluorinated ethyl methyl carbonate derivative include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-tri Examples thereof include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate and ethyl trifluoromethyl carbonate.

Examples of the fluorinated diethyl carbonate derivative include ethyl-(2-fluoroethyl)carbonate, ethyl-(2,2-difluoroethyl)carbonate, bis(2-fluoroethyl)carbonate, 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',2'-difluoroethyl carbonate, bis(2,2,2-trifluoroethyl) carbonate, etc. are mentioned.

As the chain carbonate, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.
The content of the chain carbonate is not particularly limited as long as the viscosity of the desired electrolytic solution can be obtained, but is usually 15% by volume or more, preferably 20% by volume, based on the total amount of the solvent of the non-aqueous electrolytic solution. The above is more preferably 25% by volume or more, and is usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. By setting the content of the chain carbonate in the above range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and thus the output characteristics of the non-aqueous electrolyte battery are easily set to a good range. Become.

Furthermore, by combining ethylene carbonate with a specific chain carbonate in a specific content, the battery performance can be significantly improved.
For example, when dimethyl carbonate and ethyl methyl carbonate are selected as the specific chain carbonate, the content of ethylene carbonate is not particularly limited as long as the viscosity of the desired electrolytic solution is obtained, but the non-aqueous electrolytic solution It is usually 15% by volume or more, preferably 20% by volume or more, and usually 45% by volume or less, preferably 40% by volume or less with respect to the total amount of the solvent, and the content of dimethyl carbonate is the total amount of the solvent of the non-aqueous electrolyte solution. On the other hand, it is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, and the content of ethylmethyl carbonate is usually 20% by volume or more, preferably 3% by volume.
It is 0% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less. When the content is within the above range, high-temperature stability is excellent and gas generation tends to be suppressed.

<1-3-3. Ether compounds>
As the ether compound, a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms are preferable.
As the chain ether having 3 to 10 carbon atoms, diethyl ether, di(2-fluoroethyl)ether, di(2,2-difluoroethyl)ether, di(2,2,2-trifluoroethyl)ether, ethyl (2-Fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl)ether, (2-fluoroethyl)(1,1,2,2-tetrafluoroethyl)ether, (2,2,2-trifluoroethyl)(1,1,2,2-tetrafluoro Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-)
Trifluoro-n-propyl) ether, ethyl (2,2,3,3-tetrafluoro-n
-Propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl)
Ether, 2-fluoroethyl-n-propyl ether, (2-fluoroethyl) (3-
Fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3-tetrafluoro-n- Propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl-n-propyl ether, (2,2,2 2-trifluoroethyl)(3-fluoro-n-propyl)ether,
(2,2,2-trifluoroethyl)(3,3,3-trifluoro-n-propyl)ether, (2,2,2-trifluoroethyl)(2,2,3,3-tetrafluoro- n-propyl)ether, (2,2,2-trifluoroethyl)(2,2,3,3,3-pentafluoro-n-propyl)ether, 1,1,2,2-tetrafluoroethyl-n -Propyl ether, (1,1,2,2-tetrafluoroethyl) (3-fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro -N-propyl)ether, (1,1,2,2-tetrafluoroethyl)(2,2,3
3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-propyl ether , (N-propyl)(3-fluoro-n-propyl)ether, (n-propyl)(3,3,3-trifluoro-n-propyl)ether, (n-propyl)(2,2
,3,3-Tetrafluoro-n-propyl)ether, (n-propyl)(2,2,3,
3,3-pentafluoro-n-propyl) ether, di(3-fluoro-n-propyl)
Ether, (3-fluoro-n-propyl)(3,3,3-trifluoro-n-propyl)ether, (3-fluoro-n-propyl)(2,2,3,3-tetrafluoro-n-
Propyl)ether, (3-fluoro-n-propyl)(2,2,3,3,3-pentafluoro-n-propyl)ether, di(3,3,3-trifluoro-n-propyl)ether, (3,3,3-trifluoro-n-propyl)(2,2,3,3-tetrafluoro-n-propyl)ether, (3,3,3-trifluoro-n-propyl)(2,2 , 3
,3,3-Pentafluoro-n-propyl)ether, di(2,2,3,3-tetrafluoro-n-propyl)ether, (2,2,3,3-tetrafluoro-n-propyl)(
2,2,3,3,3-pentafluoro-n-propyl)ether, di(2,2,3,3,3)
3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy(2-fluoroethoxy)methane, methoxy(
2,2,2-trifluoroethoxy)methane methoxy(1,1,2,2-tetrafluoroethoxy)methane, diethoxymethane, ethoxy(2-fluoroethoxy)methane, ethoxy(2,2,2-trifluoro Ethoxy)methane, ethoxy(1,1,2,2-tetrafluoroethoxy)methane, di(2-fluoroethoxy)methane, (2-fluoroethoxy)(2,2,2-trifluoroethoxy)methane, (2 -Fluoroethoxy) (1,1
,2,2-Tetrafluoroethoxy)methane di(2,2,2-trifluoroethoxy)methane, (2,2,2-trifluoroethoxy)(1,1,2,2-tetrafluoroethoxy)methane, di (1,1,2,2-tetrafluoroethoxy)methane, dimethoxyethane, methoxyethoxyethane, methoxy(2-fluoroethoxy)ethane, methoxy(2,
2,2-trifluoroethoxy)ethane, methoxy(1,1,2,2-tetrafluoroethoxy)ethane, diethoxyethane, ethoxy(2-fluoroethoxy)ethane, ethoxy(2,2,2-trifluoroethoxy) ) Ethane, ethoxy(1,1,2,2-tetrafluoroethoxy)ethane, di(2-fluoroethoxy)ethane, (2-fluoroethoxy)(2,2,2-trifluoroethoxy)ethane, (2- Fluoroethoxy) (1,1,
2,2-tetrafluoroethoxy)ethane, di(2,2,2-trifluoroethoxy)ethane, (2,2,2-trifluoroethoxy)(1,1,2,2-tetrafluoroethoxy)ethane, Examples include di(1,1,2,2-tetrafluoroethoxy)ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

Among these, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, or diethylene glycol dimethyl ether has a high solvating ability for lithium ions and has an ionic dissociation property. It is preferable in terms of improvement. Particularly preferred is dimethoxymethane, diethoxymethane or ethoxymethoxymethane because it has a low viscosity and gives a high ionic conductivity.

As the cyclic ether having 3 to 6 carbon atoms, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
The content of the ether compound is not particularly limited as long as the viscosity of the desired electrolytic solution can be obtained, but is usually 1 volume% or more, preferably 2 volume% or more, more preferably 100 volume% of the non-aqueous solvent. Is 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, more preferably 20% by volume or less. When the content of the ether compound is within the above-mentioned preferred range, it is easy to secure the effect of improving the lithium ion dissociation degree of the ether and the effect of improving the ionic conductivity due to the viscosity decrease. Further, when the negative electrode active material is a carbonaceous material, the phenomenon that chain ethers are co-inserted with lithium ions can be suppressed, so that the input/output characteristics and charge/discharge rate characteristics can be set within appropriate ranges.

<1-3-4. Sulfone compounds>
The sulfone-based compound is not particularly limited even if it is a cyclic sulfone or a chain sulfone, but in the case of a cyclic sulfone, it usually has 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms, and in the case of a chain sulfone Usually, a compound having 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms is preferable. The number of sulfonyl groups in one molecule of the sulfone compound is not particularly limited, but is usually 1 or 2.

Examples of the cyclic sulfone include trimethylenesulfones, tetramethylenesulfones, and hexamethylenesulfones, which are monosulfone compounds; trimethylenedisulfones, tetramethylenedisulfones, and hexamethylenedisulfones, which are disulfone compounds. Of these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones or hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

As the sulfolanes, sulfolane and/or sulfolane derivatives (hereinafter, sometimes referred to as "sulfolanes" including sulfolane) are preferable. The sulfolane derivative is preferably a sulfolane derivative in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group.
Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3
-Fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2- Fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-
Fluoro-3-methylsulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethyl Sulfolane, 3-difluoromethylsulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3-(trifluoromethyl)sulfolane, 3-fluoro-3
-(Trifluoromethyl)sulfolane, 4-fluoro-3-(trifluoromethyl)sulfolane or 5-fluoro-3-(trifluoromethyl)sulfolane is preferable in terms of high ionic conductivity and high input/output.

As the chain sulfone, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n- Butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, Trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, perfluoroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di(tri Fluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n-propyl sulfone, trifluoromethyl-n-
Propyl sulfone, fluoromethyl isopropyl sulfone, difluoromethyl isopropyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl-n-propyl sulfone, trifluoroethyl isopropyl sulfone, pentafluoroethyl-n-
Propyl sulfone, pentafluoroethyl isopropyl sulfone, trifluoroethyl-
Examples thereof include n-butyl sulfone, trifluoroethyl-t-butyl sulfone, pentafluoroethyl-n-butyl sulfone and pentafluoroethyl-t-butyl sulfone.

Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone. , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone, trifluoromethyl-n-butyl sulfone or trifluoromethyl-t. -Butyl sulfone is preferable in that the high temperature storage stability of the electrolytic solution is improved.

The content of the sulfone-based compound is not particularly limited as long as the desired viscosity of the electrolytic solution can be obtained, but is usually 0.3% by volume or more, preferably 0. It is 5% by volume or more, more preferably 1% by volume or more, and is usually 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less. When the content of the sulfone compound is within the above range, an electrolytic solution having excellent high temperature storage stability tends to be obtained.

<1-4. Auxiliary>
The non-aqueous electrolyte solution of the present invention may contain the following auxiliaries as long as the effects of the present invention are exhibited.
<1-4-1. Cyclic carbonate compound having unsaturated bond>
Cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter, "unsaturated cyclic carbonate"
May be described as “), as long as it is a cyclic carbonate having a carbon-carbon double bond or a carbon-carbon triple bond, any unsaturated carbonate can be used. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.

The unsaturated cyclic carbonate, vinylene carbonate, aromatic ring or carbon carbonate-ethylene carbonate substituted with a substituent having a carbon-carbon double bond or a carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, Examples include catechol carbonates.
Examples of the vinylene carbonates include vinylene carbonate, methylvinylene carbonate, 4,5-dimethylvinylene carbonate, phenylvinylene carbonate and 4,5-
Diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, 4,5-divinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene Carbonate, 4-fluoro-5-phenylvinylene carbonate, 4-fluoro-5-vinylvinylene carbonate, 4-allyl-5-fluorovinylene carbonate and the like can be mentioned.

Specific examples of the ethylene carbonate substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond include vinyl ethylene carbonate, 4,5-divinylethylene carbonate and 4-methyl-5- Vinyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-diethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, 4-allyl -5-ethynyl ethylene carbonate, phenyl ethylene carbonate, 4,5-diphenyl ethylene carbonate, 4-phenyl-5-vinyl ethylene carbonate, 4-allyl-5-phenyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate , 4-methyl-5-allyl ethylene carbonate and the like.

Among them, preferred unsaturated cyclic carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl. Ethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5- Mention may be made of ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate or 4-methyl-5-allyl ethylene carbonate.

Further, vinylene carbonate, vinyl ethylene carbonate or ethynyl ethylene carbonate is particularly preferable because it forms a more stable interface protective film.
The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 80 or more and 250 or less. Within this range, the solubility of the unsaturated cyclic carbonate in the non-aqueous electrolyte solution can be easily ensured, and the effects of the present invention can be sufficiently exhibited. The molecular weight of the unsaturated cyclic carbonate is more preferably 85.
It is above, and more preferably 150 or less. The method for producing the unsaturated cyclic carbonate is not particularly limited, and a known method can be arbitrarily selected and produced.

As the unsaturated cyclic carbonate, one kind may be used alone, or two kinds or more may be used in optional combination and ratio.
The amount of the unsaturated cyclic carbonate is not particularly limited as long as the desired viscosity of the electrolytic solution can be obtained, but is generally 0.001% by mass or more, preferably 0% in 100% by mass of the non-aqueous electrolytic solution. 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.1% by mass.
5 mass% or more, particularly preferably 1 mass% or more, and usually 10 mass% or less, preferably 5
It is not more than 3% by mass, more preferably not more than 3% by mass, particularly preferably not more than 2% by mass. Within this range, the non-aqueous electrolyte battery is likely to exhibit a sufficient effect of improving cycle characteristics, and
It is easy to avoid a situation in which the high temperature storage characteristics are deteriorated, the amount of gas generated is increased, and the discharge capacity maintenance ratio is decreased.

<1-4-2. Halogenated cyclic carbonate>
As an example of the cyclic carbonate compound having a halogen atom, examples of acid anhydrides mainly substituted with a fluorine atom are given below, but some or all of these fluorine atoms are replaced with a chlorine atom, a bromine atom, or an iodine atom. The acid anhydride obtained in this manner is also included in the exemplified compounds.
Examples of the cyclic carbonate compound having a halogen atom include a fluorinated product of a cyclic carbonate having an alkylene group having 2 to 6 carbon atoms, and a derivative thereof, such as a fluorinated product of ethylene carbonate and a derivative thereof. Examples of the fluorinated derivative of ethylene carbonate include a fluorinated derivative of ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Among them, ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferable.

Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-
5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate, 4-(trifluoromethyl)-ethylene carbonate, 4 -(Fluoromethyl)-4-fluoroethylene carbonate, 4-(fluoromethyl)-5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,
5-difluoro-4,5-dimethylethylene carbonate, 4,4-difluoro-5,5
-Dimethyl ethylene carbonate etc. are mentioned.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,5-difluoroethylene carbonate and 4,5-difluoroethylene carbonate gives high ionic conductivity and preferably forms an interface protective film. Is more preferable.
As the cyclic carbonate compound having a fluorine atom, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.

Further, the amount of the halogenated cyclic carbonate to be blended with respect to the entire non-aqueous electrolyte solution of the present invention is not particularly limited as long as the desired viscosity of the electrolyte solution is obtained, but the non-aqueous electrolyte solution 100% by mass.
In general, 0.001 mass% or more, preferably 0.01 mass% or more, more preferably 0.1
Mass% or more, more preferably 0.5 mass% or more, particularly preferably 1 mass% or more, and usually 10 mass% or less, preferably 7 mass% or less, more preferably 5 mass% or less, further preferably It is 3 mass% or less. However, monofluoroethylene carbonate may be used as a solvent, and in that case, the content is not limited to the above.

<1-4-3. Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively prevent the battery from bursting or igniting when the non-aqueous electrolyte battery is overcharged.
Examples of the overcharge preventing agent include biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl. Aromatic compounds such as -3-phenylindane; Partial fluorinated compounds of the above aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoro Anisole, 2
, 6-difluoroanisole, 3,5-difluoroanisole and other fluorine-containing anisole compounds; aromatics such as 3-propylphenylacetate, 2-ethylphenylacetate, benzylphenylacetate, methylphenylacetate, benzylacetate and phenethylphenylacetate Acetates; aromatic carbonates such as diphenyl carbonate and methylphenyl carbonate. Among them, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenylether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindane , 3-propylphenylacetate, 2-ethylphenylacetate, benzylphenylacetate, methylphenylacetate, benzylacetate, phenethylphenylacetate, diphenylcarbonate or methylphenylcarbonate are preferred. Even if these are used alone, 2
You may use together 1 or more types. When two or more kinds are used in combination, especially cyclohexylbenzene and t
-A combination of butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, a partially hydrogenated form of terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, and other aromatic compounds containing no oxygen It is preferable to use at least one selected from the group together with at least one selected from oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran from the viewpoint of the balance between the overcharge prevention property and the high temperature storage property.

The content of the overcharge inhibitor is not particularly limited as long as the desired viscosity of the electrolytic solution can be obtained. The content of the overcharge inhibitor is usually 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and further preferably 0% based on the total amount of the non-aqueous electrolyte solution. It is 0.5% by mass or more, and usually 5% by mass or less, preferably 4.8% by mass or less, and more preferably 4.5% by mass or less. Within this range, the effect of the overcharge inhibitor can be sufficiently exhibited, and the characteristics of the battery such as high temperature storage characteristics are improved.

<1-4-4. Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other auxiliary agents include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate and methoxyethyl-methyl carbonate; methyl-2-propynyl oxalate, ethyl-2-propynyl oxalate, bis(2 -Propynyl) oxalate,
2-propynyl acetate, 2-propynyl formate, 2-propynyl methacrylate, di(2-propynyl)glutarate, methyl-2-propynyl carbonate, ethyl-
2-propynyl carbonate, bis(2-propynyl)carbonate, 2-butyne-1,
4-diyl-dimethanesulfonate, 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, 2-propynyl-methanesulfonate, 1-methyl-2
-Propynyl-methanesulfonate, 1,1-dimethyl-2-propynyl-methanesulfonate, 2-propynyl-ethanesulfonate, 2-propynyl-vinylsulfonate,
2-propynyl-2-(diethoxyphosphoryl)acetate, 1-methyl-2-propynyl-2-(diethoxyphosphoryl)acetate, 1,1-dimethyl-2-propynyl-2
Triple bond-containing compounds such as -(diethoxyphosphoryl)acetate; 2,4,8,10-tetraoxaspiro[5.5]undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro[ 5.5] Spiro compounds such as undecane; ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolene, ethylene sulfate, vinylene sulfate, diphenyl sulfone, N,N -Sulfur-containing compounds such as dimethylmethanesulfonamide, N,N-diethylmethanesulfonamide, trimethylsilyl methyl sulfate, trimethylsilyl ethyl sulfate, 2-propynyl-trimethylsilyl sulfate; 2-isocyanatoethyl acrylate, 2-
Isocyanatoethyl methacrylate, 2-isocyanatoethyl crotonate, 2-(2-
Isocyanatoethoxy)ethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, 2-(2-isocyanatoethoxy)ethyl crotonate, and other isocyanate compounds; 1-methyl-2-pyrrolidinone, 1-methyl-2- Nitrogen-containing compounds such as piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide; hydrocarbon compounds such as heptane, octane, nonane, decane and cycloheptane; fluorobenzene , Difluorobenzene, hexafluorobenzene,
Benzotrifluoride, orthofluorotoluene, metafluorotoluene, parafluorotoluene, 1,2-bis(trifluoromethyl)benzene, 1-trifluoromethyl-
2-difluoromethylbenzene, 1,3-bis(trifluoromethyl)benzene, 1-trifluoromethyl-3-difluoromethylbenzene, 1,4-bis(trifluoromethyl)benzene, 1-trifluoromethyl-4- Difluoromethylbenzene, 1,3,5-tris(trifluoromethyl)benzene, pentafluorophenyl methanesulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl acetate,
Fluorine-containing aromatic compounds such as pentafluorophenyl trifluoroacetate and methyl pentafluorophenyl carbonate; tris(trimethylsilyl)borate, tris(trimethoxysilyl)borate, tris(trimethylsilyl)phosphate, tris(trimethoxysilyl)phosphate ), dimethoxyaluminoxytrimethoxysilane, diethoxyaluminoxytriethoxysilane, dipropoxyaluminoxytriethoxysilane, dibutoxyaluminoxytrimethoxysilane, dibutoxyaluminoxytriethoxysilane, titanium tetrakis (trimethylsiloxide), titanium Silane compounds such as tetrakis (triethylsiloxide);
2-(Methanesulfonyloxy)propionate 2-propynyl, 2-(methanesulfonyloxy)propionate 2-methyl, 2-(methanesulfonyloxy)propionate 2-ethyl, methanesulfonyloxyacetate 2-propynyl, methanesulfonyloxy Ester compounds such as 2-methyl acetate and 2-ethyl methanesulfonyloxyacetate; lithium ethylmethyloxycarbonylphosphonate, lithium ethylethyloxycarbonylphosphonate, lithium ethyl-2-propynyloxycarbonylphosphonate, lithium ethyl-1
-Methyl-2-propynyloxycarbonylphosphonate, lithium ethyl-1,1-dimethyl-2-propynyloxycarbonylphosphonate, and other lithium salts; and the like. These may be used alone or in combination of two or more. By adding these auxiliary agents, it is possible to improve the capacity retention characteristics after high temperature storage and the cycle characteristics.

The content of the other auxiliary agent is not particularly limited as long as the desired viscosity of the electrolytic solution is obtained. The content of other auxiliaries is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the total amount of the non-aqueous electrolyte solution. It is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 1% by mass or less. Within this range, the effects of other auxiliaries are likely to be sufficiently exhibited, and the high temperature storage stability tends to be improved.

<2. Non-aqueous electrolyte battery>
The non-aqueous electrolyte battery of the present invention comprises a positive electrode having a current collector and a positive electrode active material layer provided on the current collector, and a current collector and a negative electrode active material layer provided on the current collector. It is provided with a negative electrode having and capable of occluding and releasing ions, and the above-mentioned non-aqueous electrolyte solution of the present invention.

<2-1. Battery configuration>
The non-aqueous electrolyte battery of the present invention, for the configuration other than the non-aqueous electrolyte of the present invention described above,
Usually, a positive electrode and a negative electrode are laminated via a porous membrane (separator) impregnated with the non-aqueous electrolyte solution of the present invention, and these are housed in a case (exterior body). Therefore, the shape of the non-aqueous electrolyte battery of the present invention is not particularly limited, and may be any of a cylindrical type, a square type, a laminate type, a coin type, a large size and the like.

<2-2. Non-aqueous electrolyte>
As the non-aqueous electrolytic solution, the above-mentioned non-aqueous electrolytic solution of the present invention is used. In addition, it is also possible to mix and use other non-aqueous electrolyte solution with the non-aqueous electrolyte solution of the present invention without departing from the scope of the present invention.

<2-3. Negative electrode>
The negative electrode has a negative electrode active material layer on the current collector, and the negative electrode active material layer contains the negative electrode active material. Hereinafter, the negative electrode active material will be described.
The negative electrode active material of the present invention contains Si or Si oxide particles.

<2-3-1. Material of Si or Si Oxide Particles>
The Si oxide according to the present invention is SiOx in the general formula. The value of x in the above general formula is not particularly limited, but normally 0≦x<2. The SiO _x is obtained by using silicon dioxide (SiO ₂ ) and metallic silicon (Si) as raw materials. SiO _x has a larger theoretical capacity than graphite, and amorphous Si or nano-sized Si crystals are more likely to allow alkali ions such as lithium ions to come in and out, 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, still more preferably 0.6 or more, Further, it is preferably 1.8 or less, more preferably 1.6 or less, and further preferably 1.4 or less.
Within this range, the capacity is high, and at the same time, the irreversible capacity due to the combination of Li and oxygen can be reduced.

<2-3-2. Negative Electrode Active Material Containing Si or Si Oxide Particles and Graphite Particles>
The negative electrode active material according to the present invention may contain graphite particles in addition to Si or Si oxide particles. The negative electrode active material may be a mixture in which particles of Si or Si oxide and graphite particles are mixed in the form of particles independent of each other, or particles of Si or Si oxide are the surface of the graphite particles and/or It may be a complex existing inside.

The complex of Si or Si oxide particles and graphite particles (also referred to as composite particles) is not particularly limited as long as it is a particle containing Si or Si oxide particles and graphite particles. Preferably, the particles of Si or Si oxide and the graphite particles are integrated by physical and/or chemical bonding. As a more preferable form, Si or Si oxide particles and graphite particles are in a state in which the respective solid components are dispersed and present in the particles to the extent that they are present at least both on the surface of the composite particles and inside the bulk. And graphite particles are present to integrate them by physical and/or chemical bonding. A more specific preferred form is a composite material comprising at least particles of Si or Si oxide and graphite particles, wherein the graphite particles, preferably natural graphite, have a curved structure and have a folded structure. The composite material (negative electrode active material) is characterized in that particles of Si or Si oxide are present in the gaps in the structure. The gap may be a void, or graphite particles or Si
Alternatively, a substance that buffers the expansion and contraction of Si oxide particles may be present in the gap.

The content ratio of Si or Si oxide particles to the total of Si or Si oxide particles and graphite particles is usually 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 1.0% by mass or more.
It is at least mass%, more preferably at least 2.0 mass%. Also, usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, even more preferably 25% by mass or less, still more preferably 20% by mass or less, particularly It is preferably 15% by mass or less, and most preferably 10% by mass or less. Within this range, it is possible to control the side reaction on the Si surface and to obtain a sufficient capacity in the non-aqueous electrolyte battery, which is preferable.

(Coverage)
The negative electrode active material of the present invention may be coated with a carbonaceous material or a graphite material. Among them, the coating with an amorphous carbonaceous material is preferable from the viewpoint of lithium ion acceptability. This coverage is usually 0.5% or more and 30% or less, preferably 1% or more and 25% or less, more preferably 2% or more and 20% or less. The upper limit of the coverage is from the viewpoint of reversible capacity when the battery is assembled, and the lower limit of the coverage is from the viewpoint that the carbonaceous material serving as the core is uniformly coated with the amorphous carbon and strong granulation is performed, From the viewpoint of the particle size of the particles obtained when pulverized after firing, it is preferably within the above range.

Incidentally, the coverage (content rate) of the carbide derived from the organic compound of the finally obtained negative electrode active material is
The amount of the negative electrode active material, the amount of the organic compound, and the residual coal rate measured by the micro method according to JIS K 2270 can be calculated by the following formula.
Formula: Coverage rate (%) of carbide derived from organic compound = (mass of organic compound x residual carbon rate x 100)
/{Mass of negative electrode active material + (mass of organic compound x rate of residual coal)}

(Internal porosity)
The internal porosity of the negative electrode active material is usually 1% or more, preferably 3% or more, more preferably 5% or more, still more preferably 7% or more. It is usually less than 50%, preferably 40% or less, more preferably 30% or less, still more preferably 20% or less. If this internal porosity is too small, the amount of liquid in the particles of the negative electrode active material in the non-aqueous electrolyte battery tends to decrease. on the other hand,
If the internal porosity is too large, the interparticle gap tends to be small when it is used as an electrode. The lower limit of the internal porosity is preferably in the above range from the viewpoint of charge/discharge characteristics, and the upper limit is preferably in the above range from the viewpoint of diffusion of the non-aqueous electrolyte solution. Further, as described above, this gap may be a gap, or a substance that buffers the expansion and contraction of graphite particles or particles of Si or Si oxide is present in the gap or filled with the gap. It may have been done.

<2-3-3. Binder>
The negative electrode of the non-aqueous electrolyte battery of the present invention has a binder containing polyacrylic acid.
The binder according to the present invention means a material added for the purpose of binding active materials to each other and holding the active material layer on the current collector when producing the negative electrode for a non-aqueous secondary battery. By containing polyacrylic acid in the binder, the acceptability of lithium ions can be improved.
Among polyacrylic acids, sodium polyacrylate is preferable.

Examples of the material that may be contained in addition to the polyacrylic acid of the binder include methylcellulose, carboxymethylcellulose, starch, thickening polysaccharides such as carrageenan, pullulan, guar gum, xanthan gum (xanthan gum), polyethylene oxide, polypropylene oxide and the like. Vinyl alcohols such as ethers, polyvinyl alcohol and polyvinyl butyral, polyacids such as polymethacrylic acid, metal salts of these polymers, fluorine-containing polymers such as polyvinylidene fluoride, alkane polymers such as polyethylene and polypropylene, and copolymers thereof. Examples thereof include polymers. These may be used alone or in any combination of two or more at any ratio.

The content ratio of the binder to the total of the binder and the negative electrode active material is usually 0.1% by mass or more,
It is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and further preferably 2.
It is 0 mass% or more. In addition, usually 30.0 mass% or less, preferably 25.0 mass% or less,
It is more preferably 20.0% by mass or less, further preferably 15.0% by mass or less, particularly preferably 10.0% by mass or less, and most preferably 5.0% by mass or less. Within this range, it is possible to bind the active materials to each other and hold the active material layer on the current collector, and it is preferable in that a sufficient capacity can be obtained in the non-aqueous electrolyte battery.

The pH of a 1.2 wt% binder aqueous solution is usually 3.0 or more, preferably 4
． It is 0 or more, more preferably 5.0 or more, and further preferably 6.0 or more. Further, it is usually 12.0 or less, preferably 11.0 or less, more preferably 10.0 or less, further preferably 9.0 or less, particularly preferably 8.0 or less, and most preferably 7.0 or less. Within this range, it is possible to bind the active materials to each other and hold the active material layer on the current collector, and it is preferable in that a sufficient capacity can be obtained in the non-aqueous electrolyte battery.

<2-3-4. Negative electrode manufacturing method>
For manufacturing the negative electrode of the present invention, any known method can be used unless the effects of the present invention are significantly limited. For example, to the above-mentioned negative electrode active material, the above-mentioned binder, solvent, and if necessary, a conductive material, a binder, etc. are added to form a slurry, which is applied to a current collector, dried, and then pressed to form a negative electrode active material. It can be manufactured by forming a material layer.

The slurry for forming the negative electrode active material layer is usually prepared by adding a binder, a binder and the like to the negative electrode material. The “negative electrode material” in the present 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, and thus obtained. 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 within the above range.

The thickness of the negative electrode active material layer per one surface immediately before the step of injecting the non-aqueous electrolyte solution of the battery is usually 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and usually 150 μm or less. , 120 μm or less is preferable, and 100 μm or less is more preferable.
This is because when the thickness of the negative electrode active material exceeds this range, the non-aqueous electrolyte solution hardly penetrates to the vicinity of the interface of the current collector, so that the high current density charge/discharge characteristics may deteriorate. Also, if it is less than this range, the volume ratio of the current collector to the negative electrode active material increases, and the capacity of the battery may decrease. Further, the negative electrode active material may be roll-formed into a sheet electrode, or may be compression-formed into a pellet electrode.

(1) Current Collector As the current collector for holding the negative electrode active material, any known current collector can be used. Examples of the current collector of the negative electrode include metal materials such as copper, nickel, stainless steel, and nickel-plated steel, and copper is particularly preferable from the viewpoint of workability and cost.
When the current collector is made of a metal material, examples of the shape of the current collector include a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, and a foam metal. Among them, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable, and both can be used as a current collector.

Further, when the thickness of the copper foil is thinner than 25 μm, a copper alloy having higher strength than pure copper (phosphor bronze, titanium copper, Corson alloy, Cu—Cr—Zr alloy, etc.) can be used.
Although the thickness of the current collector is arbitrary, it is usually 1 μm or more, preferably 3 μm or more, and 5 μm.
The above is more preferable, and it is usually 1 mm or less, preferably 100 μm or less, and 50 μm.
It is more preferably m or less. If the thickness of the metal coating is less than 1 μm, the strength may be reduced and the coating may be difficult. If it is thicker than 1 mm, the shape of the electrode such as winding may be deformed. The current collector may have a mesh shape.

(2) Thickness Ratio of Current Collector and Negative Electrode Active Material Layer The thickness ratio of the current collector and the negative electrode active material layer is not particularly limited. The value of (material layer thickness)/(thickness of current collector)” is usually 150 or less, preferably 20 or less, more preferably 10 or less, and usually 0.1 or more, 0.4 or more, preferably 1
The above is more preferable.
When the thickness ratio of the current collector and the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge/discharge. On the other hand, if it is less than the above range, the volume ratio of the current collector to the negative electrode active material increases, and the capacity of the battery may decrease.

(3) Electrode Density The electrode structure when the negative electrode active material is formed into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g·cm ⁻³ or more, and 1. 2 g·cm ⁻³ or more is more preferable, 1.3 g·cm ⁻³ or more is further preferable, and usually 2.2 g·cm ⁻³ or less is preferable, 2.1 g·cm ⁻³ or less is more preferable, and 2. 0 g·cm ⁻³ or less is more preferable, and 1.9 g·cm ⁻³ or less is particularly preferable. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, the initial irreversible capacity increases, and the non-aqueous system near the current collector/negative electrode active material interface. Higher current density charge/discharge characteristics may be deteriorated due to a decrease in electrolyte permeability. Further, if less than the above range, the conductivity between the negative electrode active materials is reduced,
The battery resistance may increase and the capacity per unit volume may decrease.

(4) Solvent The solvent for forming the slurry is not particularly limited as long as it can dissolve or disperse the negative electrode active material, the binder, and the 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, and examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N. ，
Examples thereof include N-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphamide, dimethylsulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene and hexane.
These solvents may be used alone or in any combination of two or more at any ratio.

(5) Conductive Material Examples of the conductive materials include metal materials such as copper and nickel; carbon materials such as graphite and carbon black. These may be used alone or in any combination of two or more at any ratio. In particular, it is preferable to use a carbon material as the conductive material because the carbon material also acts as an active material. The content of the conductive material in the negative electrode material is usually 3% by mass or more, particularly preferably 5% by mass or more, and usually 30% by mass or less, particularly 25% by mass or less.
This is because if the content of the conductive material is too small, the conductivity tends to be insufficient, and if 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 strength tend to decrease. .. When two or more conductive materials are used together, the total amount of the conductive materials may be set within the above range.

(6) Binder As the binder, any material can be used as long as it is a material that is safe for the solvent and the electrolytic solution used in manufacturing the electrode. For example, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene/butadiene rubber/isoprene rubber, butadiene rubber, ethylene-acrylic acid copolymer, ethylene/methacrylic acid copolymer and the like can be mentioned. These may be used alone or in any combination of two or more at any ratio. The content of the binder is usually 0.5 parts by mass or more, preferably 1 part by mass or more, and usually 10 parts by mass or less, particularly 8 parts by mass or less, relative 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, and when the content is too large, the content of the negative electrode active material and the like is relatively insufficient, so that the battery capacity and conductivity tend to be insufficient. This is because When two or more binders are used in combination, the total amount of binders may be set within the above range.

(7) Slurry The viscosity of the slurry is not particularly limited as long as it can be applied on the current collector. The amount of the solvent used and the like may be changed at the time of preparing the slurry so that the viscosity can be applied, and the slurry can be appropriately prepared.
The obtained negative electrode current collector is coated with the obtained slurry, dried, and then pressed to form a negative electrode active material layer. The coating method is not particularly limited, and a method known per se can be used. The drying method is not particularly limited, and known methods such as natural drying, heat drying, and vacuum drying can be used.

<2-4. Positive electrode>
The positive electrode used in the non-aqueous electrolyte battery of the present invention will be described below.
<2-4-1. Positive electrode active material>
The positive electrode active material used for the positive electrode will be described below.

(1) Composition As the positive electrode active material, conventionally known materials can be appropriately used. For example, a material capable of electrochemically absorbing and desorbing lithium ions is preferable, and contains lithium, at least Ni and Co, A transition metal oxide in which 50 mol% or more of the transition metals is Ni and Co is preferable.
This is because Ni and Co have a redox potential suitable for use as a positive electrode material of a secondary battery and are suitable for high capacity applications.

The transition metal component of the lithium transition metal oxide includes Ni and Co as essential elements, but other metals such as Mn, V, Ti, Cr, Fe, Cu, Al, Mg, Zr, and E.
r and the like are mentioned, and Mn, Ti, Fe, Al, Mg, Zr and the like are preferable. Specific examples of the lithium transition metal oxide include, for example, LiCoO ₂ , LiNi _0.85 Co _0.10 Al _{0.
． 05} O ₂ , LiNi _0.80 Co _0.15 Al _0.05 O ₂ , LiNi _0.33 Co _{0
． 33} Mn _0.33 O ₂ , Li _1.05 Ni _0.33 Mn _0.33 Co _0.33 O ₂ , L
iNi _0.5 Co _0.2 Mn _0.3 O ₂ , Li _1.05 Ni _0.50 Mn _0.29 Co _{0
． 21} O ₂ , LiNi _0.6 Co _0.2 Mn _0.2 O ₂ , LiNi _0.8 Co _0.1 Mn
_Examples include _0.1 O _{2 and the} like.

Above all, a transition metal oxide represented by the following composition formula (1) is preferable.
Li _a1 Ni _b1 Co _c1 M _d1 O ₂ (1)
(In the formula (1), 0.90≦a1≦1.10, 0.50≦b1≦0.98, 0.01≦c1
<0.50, 0.01≦d1<0.50, which satisfies b1+c1+d1=1.
M is at least 1 selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti and Er.
Represents a seed element. )
In composition formula (1), it is preferable to show a numerical value of 0.1≦d1<0.5.

Since the composition ratio of Ni and Co and the composition ratio of other metal species are as specified, transition metal is difficult to elute from the positive electrode, and even if it elutes, Ni and Co are not contained in the non-aqueous secondary battery. This is because the adverse effect of is small.
Among them, a transition metal oxide represented by the following composition formula (2) is more preferable.
Li _a2 Ni _b2 Co _c2 M _d2 O ₂ (2)
(In formula (2), 0.90≦a2≦1.10, 0.50≦b2≦0.89, 0.10≦c2
<0.50, 0.01≦d2<0.40, which satisfies b2+c2+d2=1.
M is at least 1 selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti and Er.
Represents a seed element. )
In composition formula (2), it is preferable to show a numerical value of 0.10≦d2<0.40.

Since Ni and Co are main components and the composition ratio of Ni is larger than that of Co,
This is because when used as a positive electrode of a non-aqueous electrolyte battery, it is stable and a high capacity can be taken out.
Among them, transition metal oxides represented by the following composition formula (3) are more preferable.
Li _a3 Ni _b3 Co _c3 M _d3 O ₂ (3)
(In formula (3), 0.90≦a3≦1.10, 0.50≦b3≦0.89, 0.1≦c3≦
The numerical values of 0.2 and 0.01≦d3≦0.3 are shown, and b3+c3+d3=1 is satisfied. M is M
Represents at least one element selected from the group consisting of n, Al, Mg, Zr, Fe, Ti and Er. )
In composition formula (3), it is preferable to show a numerical value of 0.10≦d3≦0.3.

This is because the above composition makes it possible to take out a particularly high capacity when used as a positive electrode for a non-aqueous secondary battery.
Further, two or more kinds of the above positive electrode active materials may be mixed and used. Similarly, at least one or more of the above positive electrode active materials may be mixed with another positive electrode active material for use. Examples of other positive electrode active materials include transition metal oxides, transition metal phosphoric acid compounds, transition metal silicic acid compounds, and transition metal boric acid compounds not listed above.

Among them, a lithium manganese composite oxide having a spinel structure and a lithium-containing transition metal phosphate compound having an olivine structure are preferable. Specifically, as a lithium manganese composite oxide having a spinel structure, LiMn ₂ O ₄ , LiMn _1.8 Al _0.2 O ₄ , Li
Mn _1.5 Ni _0.5 O ₄ and the like. This is because the structure is most stable, oxygen is less likely to be released even when the non-aqueous electrolyte battery is abnormal, and the safety is excellent.

Further, as the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn,
Fe, Co, Ni, Cu and the like are preferable, and specific examples thereof include LiFePO ₄ and Li.
₃ Fe ₂ (PO ₄ ) ₃ , iron phosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , manganese phosphates such as LiMnPO ₄ Part of Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, C
Examples thereof include those substituted with other metals such as u, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn and W.

Among them, a lithium iron phosphate compound is preferable, because iron is an abundant resource, is an extremely inexpensive metal, and is less harmful. That is, of the above specific examples, LiFePO ₄ can be mentioned as a more preferable specific example.

(2) Surface coating It is also possible to use a material having a composition different from that of the material constituting the main positive electrode active material (hereinafter referred to as "surface adhering material") on the surface of the positive electrode active material. .. Examples of surface-adhering substances are aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, oxides such as bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, Examples thereof include sulfates such as calcium sulfate and aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate, and carbon.

These surface-adhering substances are, for example, a method of dissolving or suspending them in a solvent, impregnating and adding to the positive electrode active material, and then drying, and dissolving or suspending the surface-adhering substance precursor in a solvent and impregnating and adding to the positive electrode active material. After that, it can be attached to the surface of the positive electrode active material by a method of reacting by heating or the like, a method of adding to the precursor of the positive electrode active material and simultaneously firing. When carbon is attached, a method of mechanically attaching carbonaceous material in the form of activated carbon or the like can be used.

The mass of the surface-adhering substance adhering to the surface of the positive electrode active material is relative to the mass of the positive electrode active material,
It is preferably 0.1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more. Further, it is preferably 20% or less, more preferably 10% or less, still more preferably 5% or less.
The surface-adhering substance can suppress the oxidation reaction of the non-aqueous electrolyte solution on the surface of the positive electrode active material, and can improve the battery life. Further, when the amount of adhesion is within the above range, the effect can be sufficiently exhibited, and the resistance does not easily increase without inhibiting the entry and exit of lithium ions.

(3) Shape The shape of the positive electrode active material particles is a lump, polyhedron, sphere, ellipsoid, or the like as conventionally used.
A plate shape, a needle shape, a column shape, or the like is used. Further, the primary particles may be aggregated to form secondary particles, and the shape of the secondary particles may be spherical or elliptical.

(4) Manufacturing Method of Positive Electrode Active Material The manufacturing method of the positive electrode active material is not particularly limited as long as it does not exceed the scope of the present invention.
There are several methods, and a general method is used as a method for producing an inorganic compound.
In particular, various methods can be considered for producing a spherical or elliptic spherical active material. For example, as an example, transition metal raw materials such as transition metal nitrates and sulfates, and raw 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 prepare and recover a spherical precursor, which is dried if necessary, and then LiOH, Li ₂ CO ₃ , Li
A method of adding an Li source such as NO ₃ and firing at a high temperature to obtain an active material can be mentioned.

In addition, as an example of another method, transition metal raw materials such as transition metal nitrates, sulfates, hydroxides, and oxides and, if necessary, raw materials of other elements are dissolved or pulverized and dispersed in a solvent such as water. do it,
It is dried and molded with a spray dryer etc. to give a spherical or ellipsoidal precursor, and L
Examples include a method of adding an Li source such as iOH, Li ₂ CO ₃ and LiNO ₃ and firing at a high temperature to obtain an active material.

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

<2-4-2. Positive electrode structure and fabrication method>
The constitution of the positive electrode used in the present invention and the method for producing the same will be described below.
(Method for producing positive electrode)
The positive electrode is manufactured by forming a positive electrode active material layer containing positive electrode active material particles and a binder on a current collector. The positive electrode using the positive electrode active material can be manufactured by any known method. For example, a positive electrode active material, a binder, and optionally a conductive material and a thickener are mixed in a dry form to form a sheet, which is then pressure-bonded to a positive electrode current collector, or these materials are used as a liquid medium. A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by dissolving or dispersing it in a slurry to form a slurry, which is applied to the positive electrode current collector and dried.

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, further preferably 80% by mass or more, and preferably 99.9% by mass or less. Yes, 99% by mass or less is more preferable. When the content of the positive electrode active material is within the above range, sufficient electric capacity can be secured. Furthermore, the strength of the positive electrode will be sufficient. The positive electrode active material powder in the present invention may be used alone, or two or more kinds having different compositions or different powder properties may be used in any combination and ratio. When using two or more kinds of active materials in combination, it is preferable to use the composite oxide containing lithium and manganese as a powder component. Cobalt or nickel is an expensive metal with a small amount of resources, and the large amount of active material used in large batteries such as automobiles that require high capacity is not preferable in terms of cost because it is not preferable in terms of cost. This is because it is desirable to use manganese as the main component as a transition metal.

(Conductive material)
Any known conductive material can be used as the conductive material. Specific examples thereof include metal materials such as copper and nickel; graphite such as natural graphite and artificial 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 be used together by 2 or more types by arbitrary combinations and ratios.
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, further preferably 1% by mass or more, and preferably 50% by mass or less. And is more preferably 30% by mass or less, further preferably 15% by mass or less. 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 producing the positive electrode active material layer is not particularly limited as long as it is a material stable to the non-aqueous electrolyte solution and the solvent used for producing the electrode.
In the case of the coating method, it is not particularly limited as long as it is a material that is dissolved or dispersed in a liquid medium used during electrode production, but specific examples include polyethylene, polypropylene, polyethylene terephthalate, polymethylmethacrylate, aromatic polyamide, and cellulose. , Polymer polymers such as nitrocellulose; SBR (styrene/butadiene rubber), NBR (acrylonitrile/butadiene rubber), fluororubber, isoprene rubber, butadiene rubber, ethylene/
Rubber-like polymer such as propylene rubber; styrene/butadiene/styrene block copolymer or hydrogenated product thereof, EPDM (ethylene/propylene/diene terpolymer), styrene/ethylene/butadiene/ethylene copolymer, styrene・Thermoplastic elastomeric polymers such as isoprene/styrene block copolymers or hydrogenated products thereof; syndiotactic
Soft resinous polymers such as 1,2-polybutadiene, polyvinyl acetate, ethylene/vinyl acetate copolymers, propylene/α-olefin copolymers; polyvinylidene fluoride (PVdF),
Fluorine-based polymers such as polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene/ethylene copolymers; polymer compositions having ion conductivity of alkali metal ions (particularly lithium ions), and the like. These substances may be used alone or in any combination of two or more at any ratio.

The content of the binder 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. Yes, 60% by mass or less is more preferable, 40% by mass or less is further preferable, and 10% by mass or less is particularly preferable. When the proportion 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 the battery performance such as cycle characteristics becomes good. Furthermore, it also leads to avoiding a decrease in battery capacity and conductivity.

(Liquid medium)
As the liquid medium used for preparing the slurry for forming the positive electrode active material layer, it is possible to dissolve or disperse the positive electrode active material, the conductive material, the binder, and the thickener used if necessary. There is no particular limitation on the type of solvent as long as it is a solvent, and either an aqueous solvent or an organic solvent may be used.

Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of organic media include aliphatic hydrocarbons such as hexane; benzene, toluene, xylene,
Aromatic hydrocarbons such as methylnaphthalene; Heterocyclic compounds such as quinoline and pyridine; Ketones such as acetone, methyl ethyl ketone and cyclohexanone; Esters such as methyl acetate and methyl acrylate; Diethylenetriamine, N,N-dimethylaminopropylamine And the like; ethers such as diethyl ether and tetrahydrofuran (THF); amides such as N-methylpyrrolidone (NMP), dimethylformamide, and dimethylacetamide;
Aprotic polar solvents such as hexamethylphosphamide, dimethylsulfoxide and the like can be mentioned. In addition, these may be used individually by 1 type and may be used together by 2 or more types in arbitrary combinations and ratios.

(Thickener)
When an aqueous medium is used as the liquid medium for forming the slurry, it is preferable to make it into a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). Thickeners are commonly used to adjust the viscosity of slurries.
The thickener is not limited as long as it does not significantly limit the effect of the present invention, specifically, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof. Etc. These may be used alone or in any combination of two or more at any ratio.

When using a thickener, the ratio of the thickener to the positive electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 0.6% by mass or more. Preferably
Further, it is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less. Within the above range, the coatability will be good, and further, the ratio of the active material in the positive electrode active material layer will be sufficient, so that the problem of decreasing the battery capacity and the resistance between the positive electrode active materials will increase. It's easier to avoid problems.

(Consolidation)
The positive electrode active material layer obtained by applying the slurry to the current collector and drying it is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1 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, the permeability of the non-aqueous electrolyte solution to the vicinity of the current collector/active material interface does not decrease, and the charge/discharge characteristics are particularly good at high current densities. Become. further,
It becomes difficult for the conductivity between the active materials to decrease, and it becomes difficult for the battery resistance to increase.

(Current collector)
The material for the positive electrode current collector is not particularly limited, and any known material can be used.
Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium and tantalum; carbonaceous materials such as carbon cloth and carbon paper. Of these, metal materials, particularly aluminum are preferable.
Examples of the shape of the current collector include a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, and a foam metal in the case of a metal material, and a carbon plate in the case of a carbonaceous material, Examples thereof include a carbon thin film and a carbon column. Of these, metal thin films are preferred.
The thin film may be appropriately formed in a 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 further preferably 1 mm or less, 100 μm or less, more 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 secured. In addition, the handleability is also good.

The ratio of the thickness of the current collector and the thickness of the positive electrode active material layer is not particularly limited, but (the thickness of the active material layer on one surface immediately before the nonaqueous electrolytic solution injection)/(the thickness of the current collector) is preferably It is 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 thickness of the positive electrode active material layer is within the above range, it becomes difficult for the current collector to generate heat due to Joule heat during high current density charge/discharge. Furthermore, it becomes difficult for the volume ratio of the current collector to the positive electrode active material to increase, and it is possible to prevent a decrease in battery capacity.

(Electrode area)
From the viewpoint of high output and stability at 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 area of the electrode area of the positive electrode with respect to the surface area of the outer casing of the non-aqueous electrolyte battery is preferably 20 times or more, more preferably 40 times or more, in terms of area ratio. The outer surface area of the outer case is the total area obtained by calculation from the length, width, and thickness dimensions of the case part filled with the power-generating elements excluding the protruding parts of the terminals in the case of the bottomed square shape. .. In the case of a bottomed cylindrical shape, it is a geometric surface area that 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 surfaces via the collector foil. , The sum of the areas calculated for each surface separately.

(Discharge capacity)
When the non-aqueous electrolyte solution of the present invention is used, the electric capacity of the battery element housed in one battery exterior of the non-aqueous electrolyte battery (electric capacity when the battery is discharged from a fully charged state to a discharged state)
However, if it is 1 ampere hour (Ah) or more, the effect of improving the low-temperature discharge characteristics becomes large, which is preferable. Therefore, the positive electrode plate has a discharge capacity of fully charged, preferably 3 Ah (ampere hour), more preferably 4 Ah or more, preferably 100 Ah or less, more preferably 70 Ah or less, and particularly preferably 50 Ah. Design as follows.

Within the above range, the voltage drop due to the electrode reaction resistance does not become too large when a large current is taken out, and the deterioration of power efficiency can be prevented. Furthermore, the temperature distribution due to the internal heat generation of the battery during pulse charging/discharging does not become too large, the durability of repeated charging/discharging is poor, and the heat dissipation efficiency is also poor against sudden heat generation during abnormal conditions such as overcharging and internal short circuits. It is possible to avoid such a phenomenon.

(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 from which the thickness of the current collector is subtracted is preferably 10 μm or more, more preferably 20 μm or more, and preferably 200 μm or less, and 100 μm with respect to one surface of the current collector.
It is more preferably m or less.

<2-5. Separator>
A separator is usually interposed between the positive electrode and the negative electrode to prevent a short circuit. In this case, the non-aqueous electrolytic solution of the present invention is usually used by impregnating this separator.
There is no particular limitation on the material and shape of the separator, and any known material can be used as long as the effects of the present invention are not significantly impaired. Among them, formed of a material stable to the non-aqueous electrolyte of the present invention, a resin, glass fiber, an inorganic material or the like is used, and a porous sheet or a non-woven fabric-like material excellent in liquid retention is used. Is preferred.

As the material of the resin and the glass fiber separator, for example, polyolefin such as polyethylene and polypropylene, polytetrafluoroethylene, polyether sulfone, and glass filter can be used. Of these, glass filters and polyolefins are preferable, and polyolefins are more preferable. These materials may be used alone or in any combination of two or more at any ratio.

The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating property and mechanical strength may decrease. If the thickness is more than the above range, not only the battery performance such as rate characteristics may deteriorate, but also the energy density of the entire non-aqueous electrolyte battery may decrease.

Furthermore, when using a porous material such as a porous sheet or a non-woven fabric as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, and 45%.
The above is more preferable, and usually 90% or less, preferably 85% or less, more preferably 75% or less. If the porosity is less than the above range, the film resistance tends to increase and the rate characteristics tend to deteriorate. On the other hand, if it is larger than the above range, the mechanical strength of the separator tends to decrease and the insulating property tends to decrease.

The average pore size of the separator is also arbitrary, but is usually 0.5 μm or less, and 0.2 μm
The following is preferable, and it is usually 0.05 μm or more. When the average pore size exceeds the above range, short circuit is likely to occur. On the other hand, if it is less than the above range, the film resistance may increase and the rate characteristics may deteriorate.
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 the form, a thin film-shaped one such as a non-woven fabric, a woven fabric or a microporous film is used. In the form of a thin film, one 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 can be used in which a composite porous layer containing the particles of the inorganic material is formed on the surface layer of the positive electrode and/or the negative electrode using a resin binder. For example, alumina particles having a 90% particle diameter of less than 1 μm may be used on both surfaces of the positive electrode to form a porous layer using a fluororesin as a binder.

<2-6. Battery design>
[Electrode group]
The electrode group has a laminated structure including the positive electrode plate and the negative electrode plate with the separator interposed therebetween,
Also, any of the above-mentioned positive electrode plate and negative electrode plate may be spirally wound with the separator interposed therebetween. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupancy rate) is usually 40% or more, preferably 50% or more, and usually 90% or less,
80% or less is preferable. The lower limit of the electrode group occupancy rate is preferably in the above range from the viewpoint of battery capacity. In addition, the upper limit of the electrode group occupancy is to secure a gap space from the viewpoint of various characteristics such as charge/discharge repetition performance as a battery and high temperature storage, and from the viewpoint of avoiding the operation of the gas release valve that releases the internal pressure to the outside. The above range is preferable. If the gap space is too small, the internal temperature rises due to the expansion of the members due to the high temperature of the battery and the increase of the vapor pressure of the liquid component of the electrolyte, and the repeated charge/discharge performance of the battery and high temperature storage. In some cases, various characteristics may be deteriorated, and further, the gas release valve that releases the internal pressure to the outside may be activated.

[Current collecting structure]
Although the current collecting structure is not particularly limited, in order to more effectively realize the improvement of the discharge characteristics by the non-aqueous electrolyte solution of the present invention, a structure in which the resistance of the wiring portion or the joint portion is reduced is used. preferable. When the internal resistance is reduced in this way, the effect of using the non-aqueous electrolyte solution of the present invention is particularly well exhibited.

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

[Protective element]
As a protective element, PTC (Posit) whose resistance increases when abnormal heat generation or excessive current flows
Examples include an IVE Temperature Coefficient, a temperature fuse, a thermistor, and a valve (current cutoff valve) that cuts off the current flowing through the circuit due to a sudden increase in internal pressure or internal temperature of the battery during abnormal heat generation. It is preferable to select the protection element under the condition that it does not operate in high current of normal use, and from the viewpoint of high output, it is more preferable to design so as not to cause abnormal heat generation or thermal runaway without the protection element.

[Exterior body]
The non-aqueous electrolyte battery of the present invention is usually constituted by housing the above-mentioned non-aqueous electrolyte, negative electrode, positive electrode, separator and the like in an outer casing (exterior case). There is no limitation on this outer package, and any known package can be used as long as the effects of the present invention are not significantly impaired.
The material of the outer case is not particularly limited as long as it is a stable substance with respect to the non-aqueous electrolyte solution used. Specifically, nickel-plated steel plates, metals such as stainless steel, aluminum or aluminum alloys, magnesium alloys, nickel and titanium, or laminated films (laminated films) of resin and aluminum foil are preferably used.

In the outer case using the above metals, laser welding, resistance welding, ultrasonic welding to weld the metals to each other to form a sealed and sealed structure, or a caulking structure using the above metals through a resin gasket. There are things to do. Examples of the outer case using the laminate film include those having a sealed structure by heat-sealing resin layers. In order to improve the sealing property, 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 via a collector terminal to form a hermetically sealed structure, a metal and a resin are joined, so a resin having a polar group or a modification having a polar group introduced as an intervening resin. Resin is preferably used.
The shape of the outer package is also arbitrary, and may be, for example, any of a cylinder type, a square type, a laminate type, a coin type, a large size, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Reference Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

<Measurement of pH of binder aqueous solution>
Using Tescom Electric Co., Ltd. Mixer TM855, 296.4 g of water was added to 3.6 g of the binder of Examples or Comparative Examples described later, and the mixture was stirred until the binder was dissolved.
A 2 wt% aqueous solution was obtained. The pH of the obtained 1.2 wt% aqueous solution of the binder was measured at 25° C. using a conductivity system MM-60R manufactured by Toa DKK, and an electrode GST-5741C.

<Measurement method for initial charge/discharge capacity, initial efficiency, second charge/discharge capacity, second efficiency>
Using a non-aqueous electrolyte solution battery (2032 coin type battery) produced by the method described below, the capacity during charge/discharge of the battery was measured by the following measurement method.
The lithium counter electrode was charged up to 5 mV with a current density of 0.05 C (a current value that takes 1 hour for charging or discharging is 1 C, the same applies below), and the current density was 0.1 V at a constant voltage of 5 mV.
The battery was charged to 005C and discharged to 1.5V with respect to the lithium counter electrode at a current density of 0.1C. The charge capacity (mAh/g) and discharge capacity (mAh/g) at this time were taken as the initial charge capacity (mAh/g) and the initial discharge capacity (mAh/g) of the tested negative electrode material, and (initial discharge capacity/initial charge The value of (capacity)×100 (%) was taken as the initial efficiency. In addition, the second charging and discharging is performed under the same conditions, and the second charging capacity (mAh/g), the second discharging capacity (mAh/g),
The second efficiency (%) was measured.

<Production of electrode sheet>
An electrode plate was prepared by using SiO particles having an average particle diameter of 5.2 μm (Osaka Titanium Technologies Co., Ltd.) as a negative electrode active material. Specifically, the binders of the respective examples or comparative examples described later are described below.
5 g and 4.5 g of carbon black were added to 30.1 g of water, and the mixture was stirred with Awatori Kentaro AR-250 manufactured by Shinky Co., Ltd. to obtain a carbon black dispersion, and then 9 g of negative electrode material and 41.
A slurry was obtained by adding 9 g and stirring again with Awatori Kentaro AR-250 manufactured by Shinky Co., Ltd.
This slurry was placed on a copper foil having a thickness of 10 μm, which is a current collector, and the negative electrode material was 1.00±0.05.
mg/cm ² was applied to a width of 10 cm by using a coater manufactured by Sunk Co., Ltd. to obtain an electrode sheet.

<Preparation of non-aqueous electrolyte battery (2032 coin type battery)>
A 2032 type coin cell member manufactured by Hosen Co., Ltd. was used for the outer body, and the electrode sheet produced by the above method was punched into a disc shape having a diameter of 14.0 mm, and a lithium metal foil was punched into a disc shape having a diameter of 15 mm to form a counter electrode. A separator (made of a porous polyethylene film) was placed between both electrodes, and the electrolytic solution was injected so as to fill the inside of the cell with the electrolytic solution, thereby producing 2032 coin type batteries.

(Example 1)
As a binder, polyacrylic acid (Mv-450,000) manufactured by Sigma-Aldrich and sodium polyacrylate (polymerization degree 22,000-70,000) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
Using the mixture () (weight ratio=3:7), the pH of the aqueous solution of the binder was measured and the electrode sheet was prepared. In addition, LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate (volume ratio=3:3:4) to 1 mol/L as an electrolytic solution, and 1 wt% of difluorophosphate was further added. 2032
A coin-type battery was prepared and the initial charge/discharge capacity, initial efficiency, second charge/discharge capacity and second efficiency were measured. The results are shown in Table 1.

(Comparative Example 1)
The pH was measured and the electrode sheet was prepared in the same manner as in Example 1 except that 1 wt% of difluorophosphate was not added. The initial charge/discharge capacity, the initial efficiency, the second charge/discharge capacity, and the second efficiency were measured. The results are shown in Table 1.
(Comparative example 2)
Carboxymethyl cellulose (MAC500LC) from Nippon Paper Industries Co., Ltd. as a binder
The pH was measured and the electrode sheet was prepared in the same manner as in Example 1 except that was used. The initial charge/discharge capacity, the initial efficiency, the second charge/discharge capacity, and the second efficiency were measured. The results are shown in Table 1.

It is clear that by combining the binder containing polyacrylic acid and the non-aqueous electrolyte solution containing difluorophosphoric acid, the efficiency after repeated charge and discharge is improved as compared with the case where either one is satisfied.

According to the non-aqueous electrolyte battery of the present invention, efficiency after repeated charge and discharge can be increased.
Moreover, the non-aqueous electrolyte battery of the present invention can be used for various known applications using the non-aqueous electrolyte battery. Specific examples include, for example, laptop computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile fax machines, mobile copy machines, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, mini disks. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Bike, Motorized Bicycle, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Power Tool, Strobe, Camera, Home Backup Power sources, business-use backup power sources, load leveling power sources, natural energy storage power sources, etc.

Claims (4)

A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte,
The negative electrode has a negative electrode active material containing particles of Si or Si oxide, and a binder containing polyacrylic acid,
A non-aqueous electrolyte battery in which the non-aqueous electrolyte contains difluorophosphate. The non-aqueous electrolyte battery according to claim 1, wherein the 1.2 wt% aqueous solution of the binder has a pH of 3 to 7. The non-aqueous electrolyte battery according to claim 1, wherein the binder contains sodium polyacrylate. The negative electrode active material further contains graphite particles, and the content of the Si or Si oxide particles is 0.1 to 20 mass% with respect to the total of the Si or Si oxide particles and the graphite particles. The non-aqueous electrolyte battery according to any one of claims 1 to 3.