JP7012550B2 - Non-aqueous electrolyte and non-aqueous electrolyte batteries - Google Patents

Description

The present invention relates to a non-aqueous electrolyte solution and a non-aqueous electrolyte battery using the same.

Non-aqueous electrolyte batteries such as lithium secondary batteries are being put to practical use 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 driving such as automobiles. However, in recent years, the demand for higher performance of non-aqueous electrolyte batteries has been increasing, and in particular, various battery characteristics such as high capacity, low temperature use characteristics, high temperature storage characteristics, cycle characteristics, and safety during overcharging have been increasing. Is requested to be improved.

In addition, in order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, etc. of such non-aqueous electrolyte batteries, and to improve battery safety during overcharging, various non-aqueous solvents, electrolytes, and additives are used. Studies have been made to protect the battery by increasing the internal resistance at a battery voltage above the maximum operating voltage of the battery, or by generating gas and pressure at a battery voltage above the maximum operating voltage of the battery. An overcharge inhibitor is used for the purpose of reliably operating the internal electric cutting device provided for charge protection. As the overcharge inhibitor, aromatic hydrocarbon compounds, aromatic ester compounds, phosphorus compounds and the like are known. Among these, in Patent Document 1, as an example of a phosphorus-based compound, when an aromatic phosphoric acid ester in which all phenyl groups are substituted with an alkyl group having 4 or more carbon atoms is used as an overcharge inhibitor, the high temperature storage property is excellent. Is described.

Japanese Unexamined Patent Publication No. 2014-135296

According to the study of the present inventor, the non-aqueous electrolytic solution secondary battery using the electrolytic solution described in Patent Document 1 improves the child temperature storage characteristics as described above, but is safe during overcharging. I was not satisfied with the improvement. In view of this problem, it is an object of the present invention to provide a non-aqueous electrolyte battery excellent in safety at the time of overcharging and continuous charging characteristics, and a non-aqueous electrolytic solution to give the battery.

As a result of various studies to achieve the above object, the present inventors have found that the above problems can be solved by containing a phosphorus-based compound having a specific structure in the electrolytic solution, and the present invention has been developed. It came to be completed. That is, the gist of the present invention is as shown below.

［式（１）中、Ｒ^１～Ｒ^１０はそれぞれ独立して、水素、ハロゲン又は炭素数１以上１０
以下のハロゲンで置換されていてもよい炭化水素基である。Ｘはハロゲン、ＰＯ（ＯＲ^１
１）_２、ＳＯ_２ＯＲ^１２又はＣＮであり、Ｒ^１１およびＲ^１２は置換基を有していてもよ
い炭素数１～１０の飽和又は置換基を有していてもよい不飽和脂肪族炭化水素基又は置換
基を有していてもよい炭素数６～１０の芳香族炭化水素基である。Ｙはヘテロ原子を含ん
でいてもよい炭素数１～１０の飽和炭化水素基、ヘテロ原子を含んでいてもよい炭素数２
～１０の不飽和脂肪族炭化水素基又は置換基を有していてもよい炭素数６～１０の芳香族
炭化水素基である。］ [1] A non-aqueous electrolyte solution containing a non-aqueous solvent and a compound represented by the following formula (1).

[In the formula (1), R ¹ to R ¹⁰ are independently hydrogen, halogen, or have 1 or more carbon atoms and 10 or more.
It is a hydrocarbon group that may be substituted with the following halogens. X is halogen, PO (OR ¹ )
¹ ) ₂ , SO ₂ OR ¹² or CN, where R ¹¹ and R ¹² may have substituents, saturated or unsaturated aliphatic hydrocarbons having 1 to 10 carbon atoms. It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a hydrogen group or a substituent. Y is a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and 2 which may contain a heteroatom.
It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have an unsaturated aliphatic hydrocarbon group of 10 to 10 or a substituent. ]

[2] The non-aqueous electrolyte solution according to [1], wherein the non-aqueous solvent contains 0.001 to 20% by mass of the compound represented by the formula (1).

[3] The non-aqueous solvent contains at least one of LiPF ₆ and LiBF ₄ , [
The non-aqueous electrolyte solution according to 1] or [2].

[4] At least one of LiPF ₆ and LiBF ₄ is added to 0.5 to 0.5 in the non-aqueous solvent.
The non-aqueous electrolyte solution according to [3], which is contained at a concentration of 3.0 mol / L.

[5] A non-aqueous electrolyte battery containing a positive electrode and a negative electrode, and the non-aqueous electrolyte solution according to any one of [1] to [4].

According to the present invention, there is provided a non-aqueous electrolyte solution capable of improving safety at the time of overcharging without significantly impairing the battery characteristics, and a non-aqueous electrolyte battery using the same.

Hereinafter, the present invention will be described in detail. The following description is an example (representative example) of the present invention, and the present invention is not limited thereto. Further, the present invention can be arbitrarily modified and implemented without departing from the gist thereof.

[Non-aqueous electrolyte solution]
The non-aqueous electrolyte solution of the present invention contains a non-aqueous solvent and a compound represented by the following formula (1). In the following, the compound represented by the formula (1) may be referred to as "compound (1)".

[In the formula (1), R ¹ to R ¹⁰ are independently hydrogen, halogen, or have 1 or more carbon atoms and 10 or more.
It is a hydrocarbon group that may be substituted with the following halogens. X is halogen, PO (OR ¹ )
¹ ) ₂ , SO ₂ OR ¹² or CN, where R ¹¹ and R ¹² may have substituents, saturated or unsaturated aliphatic hydrocarbons having 1 to 10 carbon atoms. It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a hydrogen group or a substituent. Y has a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and Y has an unsaturated aliphatic hydrocarbon group or a substituent having 2 to 10 carbon atoms which may contain a heteroatom. It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may be present. ]

The non-aqueous electrolyte solution of the present invention has the effect that the safety during overcharging can be improved without significantly impairing the battery characteristics. The reason why the present invention exerts such an effect is not clear, but it is presumed to be due to the following reasons. That is, the compound represented by the formula (1) forms a fluorene skeleton having a lower oxidation potential by reacting under a constant potential, and this continuously reacts to form a polymerization product, thereby forming an internal resistance. It is presumed that it is possible to increase the safety during overcharging.

<1. Compound (1)>
The non-aqueous electrolyte solution of the present invention contains the compound represented by the above formula (1). In the formula (1), R ¹ to R ¹⁰ are each independently a hydrocarbon group which may be substituted with hydrogen, a halogen, or a halogen having 1 or more and 10 or less carbon atoms. Here, when at least one of R ¹ to R ¹⁰ is a hydrocarbon group, examples of the halogen that may be substituted include fluorine, iodine, and bromine, and among these, fluorine is preferable. As R ¹ to R ¹⁰ ,
Hydrogen is preferred.

In the formula (1), X is halogen, PO (OR ¹¹ ) ₂ , SO ₂ OR ¹² or CN.
Is. As X, PO (OR ¹¹ ) ₂ is particularly preferable. Here, R ¹¹ and R ¹²
Has a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and an unsaturated aliphatic hydrocarbon group or a substituent having 2 to 10 carbon atoms which may have a substituent. It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may be used. Among these, an aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferable, and a saturated aliphatic hydrocarbon group having 1 to 4 carbon atoms is particularly preferable. The substituents that may be present in R ¹¹ and R ¹² include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an i-propyl group, an s-butyl group, and an i-butyl group. , T-butyl group, cyclohexyl group, vinyl group, allyl group, propargyl group, trifluoromethyl group, pentafluoroethyl group, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2 -T-butylphenyl group, 3-t-butylphenyl group, 4-t-butylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2-trifluoromethylphenyl group, 3 -Trifluoromethylphenyl group, 4-trifluoromethylphenyl group, cyano group and the like can be mentioned.

In the formula (1), Y is a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, an unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms which may contain a heteroatom, or It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a substituent. Here, examples of the hetero atom that may be contained in Y include fluorine, oxygen, nitrogen, sulfur and the like, and examples of the substituent here include a fluoro group, a carbonyl group, an acyl group, a sulfonyl group and a sulfonyl group. Examples thereof include an oxy group and a cyano group. Specifically, Y is a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an i-propyl group, an s-butyl group, an i-butyl group, t.
-Butyl group, cyclohexyl group, vinyl group, allyl group, propargyl group, trifluoromethyl group, pentafluoroethyl group, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2-t -Butylphenyl group, 3-t-butylphenyl group, 4-t-butylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-
Fluorophenyl group, 2-trifluoromethylphenyl group, 3-trifluoromethylphenyl group, 4-trifluoromethylphenyl group, cyano group and the like can be mentioned, and methyl group, ethyl group, n-propyl group and n are preferable. -Butyl group, i-propyl group, s-butyl group, i-
A butyl group, a t-butyl group, a cyclohexyl group, a trifluoromethyl group, a pentafluoroethyl group, a phenyl group and the like are used, and a phenyl group is particularly preferable.

In particular, in the above formula (1), it is preferable that X is PO (OR ¹¹ ) ₂ and Y is a phenyl group. More specifically, among the compounds represented by the above formula (1), dimethyl triphenylmethanephosphonate, diethyl triphenylphosphonate and the like are preferable.

The content of the compound represented by the formula (1) in the non-aqueous electrolyte solution is not particularly limited as long as the effect of the present invention is not significantly impaired. Specifically, the lower limit of the content of this compound is preferably 0.001% by mass or more, more preferably 0.05% by mass or more, based on 100% by mass of the non-aqueous solvent. , 0.1% by mass or more is more preferable. The upper limit is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less with respect to 100% by mass of the non-aqueous solvent. When the concentration of this compound is within the above-mentioned preferable range, the effect of enhancing the safety at the time of overcharging is more likely to be exhibited without impairing the performance of other batteries.

Specific examples of the compound represented by the formula (1) include a group of compounds represented by the formulas (1-1) to (1-5). Among these, the compound group represented by the formulas (1-1) to (1-4) is preferable, and the compound group represented by the formulas (1-1) to (1-3) is more preferable. A group of compounds represented by the formula (1-1) or the formula (1-2) is more preferable.
A group of compounds represented by the formula (1-1) is particularly preferable.

<2. Non-aqueous solvent>
Like a general non-aqueous electrolyte solution, the non-aqueous electrolyte solution of the present invention usually contains, as a main component thereof, a non-aqueous solvent that dissolves an electrolyte to be post-operated. The non-aqueous solvent used here is not particularly limited, and known organic solvents can be used. The organic solvent is preferably a saturated cyclic carbonate, a chain carbonate, a chain carboxylic acid ester, a cyclic carboxylic acid ester, and the like.
At least one selected from ether compounds other than compound (1) and sulfone compounds.
One is mentioned, but the present invention is not particularly limited to these. These can be used individually by 1 type or in combination of 2 or more types.

<2-1. Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms. Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, butylene carbonate and the like. Of these, ethylene carbonate and propylene carbonate are preferable from the viewpoint of improving battery characteristics due to the improvement in the degree of lithium ion dissociation. As the saturated cyclic carbonate, one type may be used alone, or two or more types may be used in combination in any combination and ratio.

The content of the saturated cyclic carbonate is not particularly limited and is arbitrary as long as the effect of the present invention is not significantly impaired. It is 3% by volume or more, preferably 5% by volume or more. By setting this range, it is easy to avoid the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte solution, and to make the large current discharge characteristics of the power storage device, the stability with respect to the negative electrode, and the cycle characteristics within a good range. .. The upper limit is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting this range, the viscosity of the non-aqueous electrolyte solution can be set to an appropriate range, the decrease in ionic conductivity can be suppressed, the input / output characteristics of the power storage device can be further improved, and the durability such as cycle characteristics and storage characteristics can be improved. It is preferable because it can be further improved.

<2-2. Chain carbonate>
The chain carbonate is preferably one having 3 to 7 carbon atoms. Specifically, the number of carbon atoms is 3 to
Examples of the chain carbonate of 7 include dimethyl carbonate, diethyl carbonate, and di-n.
-Propyl carbonate, diisopropyl carbonate, n-propylisopropylcarbonate, ethylmethylcarbonate, methyl-n-propylcarbonate, n-butylmethylcarbonate, isobutylmethylcarbonate, t-butylmethylcarbonate,
Examples thereof include ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate and the like. Among these, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethylmethyl carbonate,
Methyl-n-propyl carbonate is preferable, and dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate are particularly preferable.

In addition, chain carbonates having a fluorine atom (hereinafter, "fluorinated chain carbonate").
May be abbreviated as. ) 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, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethylmethyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

As the chain carbonate, one type may be used alone, or two or more types may be used in combination in any combination and ratio.

The content of the chain carbonate is not particularly limited, but is usually 15 in 100% by volume of the non-aqueous solvent.
By volume or more, preferably 20% by volume or more, more preferably 25% by volume or more.
Further, it is usually 90% by volume or less, preferably 85% by volume or less, and 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 in an appropriate range, the decrease in ionic conductivity is suppressed, and the input / output characteristics and charge / discharge rate characteristics of the power storage device are good. It becomes easier to make a range. In addition, the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte solution is avoided, and the input / output characteristics and charge / discharge rate characteristics of the power storage device can be easily set in a good range.

<2-3. Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having a total carbon number of 3 to 7 in the structural formula. Specifically, methyl acetate, ethyl acetate, -n-propyl acetate, isopropyl acetate, -n-butyl acetate, isobutyl acetate, -t-butyl acetate, methyl propionate, ethyl propionate, -n-propyl propionate, Isopropyl propionate, propionic acid-n
-Butyl, isobutyl propionate, -t-butyl propionate, methyl butyrate, ethyl butyrate, -n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, -n-propyl isobutyrate, isopropyl isobutyrate, etc. Be done. Among these, methyl acetate, ethyl acetate, -n-propyl acetate, -n-butyl acetate, methyl propionate, ethyl propionate, -n-propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate and the like have viscosities. It is preferable from the viewpoint of improving the ionic conductivity due to the decrease and suppressing the battery swelling during the durability test such as cycle and storage.

<2-4. Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having a total carbon atom number of 3 to 12 in the structural formula. Specific examples thereof include gamma-butyrolactone, gamma valerolactone, gamma caprolactone, and epsilon caprolactone. Among these, gamma-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from the improvement of the degree of lithium ion dissociation.

<2-5. Ethereous compounds other than compound (1)>
As the ether-based compound other than the compound (1), a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms other than the compound (1) are preferable.

Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, and 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-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-tetrafluoro-n-propyl)
2,2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3,3)
3-Pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy (2-fluoroethoxy) methane, methoxy (
2,2,2-Trifluoroethoxy) Methanemethoxy (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) methanedi (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)
2,2-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 thereof include di (1,1,2,2-tetrafluoroethoxy) ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether and the like.

Examples of the cyclic ether having 3 to 6 carbon atoms other than the compound (1) include tetrahydrofuran and 2-.
Methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-
Examples thereof include methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1,4-dioxane and the like, and fluorinated compounds thereof. Among these, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvation ability to lithium ions and are lithium ion dissociative. It is preferable in terms of improving. Particularly preferred are dimethoxymethane, diethoxymethane, and ethoxymethoxymethane because they have low viscosity and give high ionic conductivity.

<2-6. Sulfone compounds other than compound (1)>
As the sulfone-based compound other than the compound (1), a cyclic sulfone having 3 to 6 carbon atoms other than the compound (1) and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.

Cyclic sulfones other than the compound (1) include trimethylene sulfones, tetramethylene sulfones, hexamethylene sulfones, which are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, hexamethylene disulfones, etc., which are disulfone compounds. Can be mentioned. Among these, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable, from the viewpoint of dielectric constant and viscosity.

As the sulfolanes, sulfolanes and / or sulfolane derivatives (hereinafter, sulfolanes may be abbreviated as "sulfolanes") are preferable. As the sulfolane derivative, one in which one or more of the hydrogen atoms bonded on the carbon atom constituting the sulfolane ring is substituted with a fluorine atom or an alkyl group is preferable.

Among these, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorolane Sulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3 -Methyl sulfolane, 4-fluoro-2-methyl sulfolane, 5-
Fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane,
3-Difluoromethyl sulfolane, 2-trifluoromethyl sulfolane, 3-trifluoromethyl sulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro- 3- (Trifluoromethyl) sulfolane, 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in that they have high ionic conductivity and high input / output.

Examples of the chain sulfone include 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, and n-. Butylmethyl sulfone, n-butylethyl sulfone, t-butylmethyl sulfone, t-butylethyl sulfone, monofluoromethylmethyl sulfone, difluoromethylmethyl sulfone, trifluoromethylmethyl sulfone, monofluoroethylmethyl sulfone, difluoroethylmethyl sulfone, Trifluoroethyl Methyl Sulfone, Pentafluoroethyl Methyl Sulfone, Ethyl Monofluoro Methyl Sulfone, Ethyl Difluoro Methyl Sulfone, Ethyl Trifluoro Methyl Sulfone, Perfluoro Ethyl Methyl Sulfone, Ethyl Trifluoro Ethyl Sulfone, Ethyl Pentafluoro Ethyl 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, pentafluoroethyl-t-butyl sulfone and the like.

Among these, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-
Propylmethyl sulfone, isopropylmethyl sulfone, n-butylmethyl sulfone, t
-Butylmethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, monofluoroethylmethylsulfone, difluoroethylmethylsulfone, trifluoroethylmethylsulfone, pentafluoroethylmethylsulfone, ethylmonofluoromethylsulfone , Ethyldifluoromethylsulfone, Ethyltrifluoromethylsulfone, Ethyltrifluoroethylsulfone, Ethylpentafluoroethylsulfone, Trifluoromethyl-n-propylsulfone, Trifluoromethylisopropylsulfone, Trifluoroethyl-n-butylsulfone, Trifluoro Ethyl-t-butyl sulfone, trifluoromethyl-n-butyl sulfone, trifluoromethyl-t-butyl sulfone and the like are preferable in that they have high ionic conductivity and high input / output.

<3. Electrolyte>
The non-aqueous electrolyte solution of the present invention usually contains an electrolyte. In particular, when the non-aqueous electrolyte solution of the present invention is a lithium ion secondary battery, it usually contains a lithium salt. The following lithium salt (A) is used to increase the ionic conductivity of the non-aqueous electrolyte solution, and a lithium salt other than the lithium salt (A) is used to further enhance the desired performance of the non-aqueous electrolyte solution of the present invention. (B) can also be used. When the non-aqueous electrolyte solution of the present invention is used for a sodium ion secondary battery,
For each of the lithium salts exemplified below, it is preferable to use a sodium salt in which lithium ions are replaced with sodium ions.

Examples of the lithium salt (A) that can be used in the non-aqueous electrolyte solution of the present invention include Li.
Examples thereof include ClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , and LiTaF ₆ . Among these, it is preferable to include at least one of LiBF ₄ and LiPF ₆ . Further, the lithium salt (A) may be used alone or in combination of two or more.

When the non-aqueous electrolyte solution of the present invention contains the lithium salt (A), the content thereof is relative to the non-aqueous solvent.
It is preferably 0.5 mol / L or more, more preferably 0.6 mol / L or more, and
It is more preferably 0.7 mol / L or more, while it is preferably 3 mol / L or less, more preferably 2 mol / L or less, and further preferably 1.8 mol / L or less. When the content of the lithium salt (A) is within the above range, the ionic conductivity can be appropriately increased.

Further, as the lithium salt (B) that can be used in the non-aqueous electrolyte solution of the present invention, LiC is used.
F ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ )
₂ N, Li (CF ₃ ) SO ₂ ) ₃ C, LiBF ₃ (C ₂ F ₅ ), LiB (C ₂ O ₄ ) ₂ ,
Examples thereof include LiB (C ₆ F ₅ ) ₄ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPO ₂ F ₂ , LiFSO ₃ . These may be used alone or in combination of two or more.

When the non-aqueous electrolyte solution of the present invention contains a lithium salt (B), the content thereof is relative to that of the non-aqueous solvent.
It is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, while
It is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, and particularly preferably 5% by mass or less. When the content of the lithium salt (B) is within the above range, the ionic conductivity can be appropriately increased.

The method for measuring the content of the lithium salt mentioned above is not particularly limited, and a known method can be arbitrarily used. Examples of such a method include ion chromatography, F magnetic resonance spectroscopy and the like.

<4. Other additives>
In addition to the various compounds listed above, the non-aqueous electrolyte solution of the present invention has malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azelanitrile, sebaconitrile, undecandinitrile, and dodecane as storage property improving agents. Compounds having a cyano group such as dinitrile; as a negative electrode protective agent, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,
3-Phenylene diisocyanate, 1,4-Phenylene diisocyanate, 1,2-bis (isocyanatomethyl) benzene, 1,3-bis (isocyanatomethyl) benzene, 1,
Diisosyanato compounds such as 4-bis (isocyanatomethyl) benzene; as durability improvers, acrylic acid anhydride, 2-methylacrylic acid anhydride, 3-methylacrylic acid anhydride, benzoic acid anhydride, 2-methylbenzoic acid anhydride Acid Anhydride, 4-Methylbenzoic Acid Anhydride, 4-tert-
Auxiliary of carboxylic acid anhydride compounds such as butyl benzoic acid anhydride, 4-fluorobenzoic acid anhydride, 2,3,4,5,6-pentafluorobenzoic acid anhydride, methoxygic acid anhydride, ethoxyformic acid anhydride and the like. Agent; As an overcharge inhibitor, cyclohexylbenzene, t-butylbenzene,
Various additives such as t-amylbenzene, biphenyl, alkyl biphenyl, terphenyl, partially hydrogenated terphenyl, diphenyl ether and dibenzofuran can be blended within a range that does not significantly impair the effects of the present invention. These compounds may be used in combination as appropriate.

[Non-aqueous electrolyte battery]
The non-aqueous electrolytic solution, the positive electrode and the negative electrode of the present invention can be used as a non-aqueous electrolytic solution (hereinafter, may be referred to as “the non-aqueous electrolytic solution battery of the present invention”). Examples of the non-aqueous electrolyte battery include a lithium ion secondary battery, a sodium ion secondary battery, and the like, but a lithium ion secondary battery is preferable. A lithium ion secondary battery usually has a non-aqueous electrolyte solution of the present invention, a current collector, and a positive electrode having a positive electrode active material layer provided on the current collector and capable of storing and releasing lithium ions. It has a negative electrode active material layer provided on the electric body and the current collector, and includes a negative electrode capable of storing and releasing lithium ions.

<1. Positive electrode>
The positive electrode used in the non-aqueous electrolyte battery of the present invention usually contains a composite oxide, a polyanionic compound, a fluoride and the like. The positive electrode usually has a positive electrode active material layer on the current collector, and the positive electrode active material layer contains a positive electrode active material. Hereinafter, the positive electrode active material will be described.

Examples of the composite oxide include those represented by the following formula (2).
Li _x M _1-y N _y O ₂ (2)

In the formula (2), 0 <x <1.2 and 0 <y <1.

M in the formula (2) is a transition metal, preferably Mn, Fe, Co, and Ni.
As M in the formula (2), only one kind may be contained in the composite oxide, or a plurality of different kinds may be contained.

N in the formula (2) is V, Fe, Cu, Nb, Mo, Ta, W, Zn, Ti, Zr, A.
At least one selected from l, B, Mg, Li, Na and K. Among these, at least one selected from V, Fe, Cu, Nb, Mo, Ta and W from the viewpoint of output improvement.
Of these, at least one selected from Nb, Mo, Ta and W is more preferable. On the other hand, from the viewpoint of the capacity retention rate after the durability test, Zn, Ti, Zr, Al, B,
At least one selected from Mg, Li, Na and K is preferred, among which Zr,
At least one selected from Al, Mg and Li is more preferable.

Preferred composite oxides include, for example, Na _2/3 Fe _1/2 Mn _1/2 O ₂ ;
Na _2/3 Ni _1/2 Mn _1/2 O ₂ , Na _2/3 Ni _1/3 Mn _2/3 O ₂ , Na _{4 /
5} Ni _1/3 Mn _2/3 O ₂ , NaCoO ₂ , NaCrO ₂ , NaNi _1/3 Co _1/3
Examples thereof include Mn _1/3 O ₂ and NaNi _1/3 Fe _1/3 Mn _1/3 O ₂ .

Examples of the polyanionic compound include those represented by the following formula (3).
Na _{x` M'y` (} QO ₄ ) z (3)

In the formula (3), 1 <x` <2, 1 <y` <3, 1 <z <3.

M'in the formula (3) is a transition metal, preferably Mn, Fe, Co, and Ni. M'in the formula (3) may contain only one kind of the polyanion compound, or may contain a plurality of different kinds.

Q in the formula (3) is P, As, Sb, Bi, S, Se, Te, Po, Si, Ge, S.
At least one selected from n and Pb. Among these, at least one selected from P, S, and Si is preferable from the viewpoint of compound stability, and among these, P and S are preferable.
At least one selected from is more preferred.

Preferred polyanionic compounds include, for example, LiFePO ₄ , Li ₂ Fe ₃
(PO ₄ ) ₃ , Li ₂ Fe ₂ (SO ₄ ) ₃ , Li ₂ Fe ₂ (SiO ₄ ) ₃ , LiMnPO
₄ , LiMnFe ₂ (PO ₄ ) ₃ , Li ₂ Mn ₂ (SO ₄ ) ₃ , Li ₂ Mn ₂ (SiO ₄ )
) ₃ and so on.

The fluoride is, for example, LiM''F ₃ , Li ₂ M''PO ₄ F (where M'' is
It is a transition metal, preferably Mn, Fe, Co, Ni, and may contain only one type or may contain a plurality of different types). For example, LiFeF ₃ , Li ₂ FePO ₄
Examples include F, LiFMnF ₃ , Li ₂ MnPO ₄ F, LiFNiF ₃ , Li ₂ NiPO ₄ F and the like.

Among the above-mentioned positive electrodes, those containing a composite oxide, a polyaniline compound and a fluoride are preferable, but other positive electrode active materials may be contained as long as the effects of the present invention are not impaired. The other positive electrode active material is not particularly limited as long as it does not correspond to any of the composite oxide, the polyanionic compound and the fluoride and can occlude and release s-block metal ions electrochemically. However, for example, a substance containing an alkali metal and at least one transition metal is preferable. Specific examples include a lithium transition metal composite oxide, a lithium-containing transition metal phosphoric acid compound, and a lithium-containing transition metal silicic acid compound. For example, Na ₂ FeP ₂ O ₇ and Na ₄ Fe ₃ (PO ₄ ) ₂ (P ₂ O ₇ ) and the like can be mentioned. The above-mentioned other positive electrode active materials may be used alone or in combination of two or more.

<2. Negative electrode>
The negative electrode usually has a negative electrode active material layer on the current collector, and the negative electrode active material layer contains a negative electrode active material. Hereinafter, the negative electrode active material will be described.

As the negative electrode active material, any material that can electrochemically occlude and release s-block metal ions such as lithium ion, lithium ion, potassium ion, and magnesium ion.
There are no particular restrictions. Specific examples thereof include carbonaceous materials, metal alloy materials, s-block metal-containing metal composite oxide materials, and the like. One of these may be used alone, or two or more thereof may be arbitrarily combined and used in combination.

Examples of the carbonaceous material used as the negative electrode active material include natural graphite, non-graphitized carbon, artificial carbonaceous material, etc., but there is no particular limitation, and usually, a pore structure is available in which lithium ions can be inserted and removed. do it. Specifically, the porous single-phase material described in WO2014 / 188722 (Patent Document 1) is preferable from the viewpoint of high capacity.

<3. 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 electrolyte solution of the present invention is usually used by impregnating this separator.

The material and shape of the separator are not particularly limited, and any known separator can be used as long as the effect of the present invention is not significantly impaired. Among these, resins, glass fibers, inorganic substances, etc., which are made of a material stable to the non-aqueous electrolyte solution of the present invention, are used, and porous sheets or non-woven fabrics having excellent liquid retention properties are used. It is preferable to use it.

As the material of the resin and the glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, polytetrafluoroethylene, polyether sulfone, glass filter and the like can be used. Among these, glass filters and polyolefins are preferable, and polyolefins are more preferable. One of these materials may be used alone, or two or more of these materials may be used in any combination and 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, and more preferably 30 μm or less. If the separator is too thin than the above range, the insulating property and the mechanical strength may be deteriorated. Further, if it is too thick than the above range, not only the battery performance such as rate characteristics may deteriorate, but also the energy density of the entire power storage device may decrease.

Further, when a porous material such as a porous sheet or a non-woven fabric is used as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, preferably 45%.
The above is more preferable, and usually 90% or less, 85% or less is preferable, and 75% or less is more preferable. If the porosity is too smaller 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 is lowered and the insulating property tends to be lowered.

The average pore diameter of the separator is also arbitrary, but is usually 0.5 μm or less, 0.2 μm.
The following is preferable, and it is usually 0.05 μm or more. If the average hole diameter exceeds the above range, a short circuit is likely to occur. Further, if it is below 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, and have a particle shape or a fiber shape. Things are used.

As the form, a thin film such as a non-woven fabric, a woven cloth, or a microporous film is used. As the thin film shape, a thin film 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 independent thin film shape, a separator obtained by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, alumina particles having a 90% particle size of less than 1 μm may be formed on both sides of the positive electrode by using a fluororesin as a binder to form a porous layer.

<4. Conductive material>
The positive electrode and the negative electrode described above may contain a conductive material in order to improve conductivity. As the conductive material, a known conductive material can be arbitrarily used. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; carbonaceous materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

The conductive material is usually 0.01 part by mass or more, preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and usually 50 parts by mass or less with respect to 100 parts by mass of the positive electrode material or the negative electrode material.
It is preferably used so as to contain 30 parts by mass or less, more preferably 15 parts by mass or less.
If the content is lower than the above range, the conductivity may be insufficient. If it exceeds the above range, the battery capacity may decrease.

<5. Binder>
The positive electrode and the negative electrode described above may contain a binder in order to improve the binding property. The binder is
The material is not particularly limited as long as it is a material that is stable to a non-aqueous electrolyte solution and a solvent used in manufacturing the electrode.

In the case of the coating method, any material may be used as long as it is a material that is dissolved or dispersed in the liquid medium used for manufacturing the electrode. Specific examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polymethylmethacrylate, aromatic polyamide, cellulose, and nitro. Resin-based polymers such as cellulose; rubber-like polymers such as SBR (styrene / butadiene rubber), NBR (acrylonitrile / butadiene rubber), fluororubber, isoprene rubber, butadiene rubber, ethylene / propylene rubber; styrene / butadiene / styrene block Copolymer or hydrogen additive thereof, EPDM (ethylene / propylene / diene ternary copolymer), styrene / ethylene /
Thermoplastic elastomeric polymers such as butadiene / ethylene copolymers, styrene / isoprene / styrene block copolymers or their hydrogenated additives; syndiotactic-1,2-polybutadiene, polyvinylidene acetate, ethylene / vinyl acetate copolymers. Soft resinous polymers such as coalesced products, propylene / α-olefin copolymers; polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers, etc. Nucleus; Examples thereof include polymer compositions having ionic conductivity of alkali metal ions (particularly lithium ions). In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

The ratio of the binder is usually 0.1 part by mass or more, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and usually 50 parts by mass with respect to 100 parts by mass of the positive electrode material or the negative electrode material. It is less than or equal to, preferably 30 parts by mass or less, more preferably 10 parts by mass or less, and further preferably 8 parts by mass or less. When the ratio of the binder is within the above range, the binding property of the electrode can be sufficiently maintained, the mechanical strength of the electrode is maintained, and it is preferable from the viewpoint of cycle characteristics, battery capacity and conductivity.

<6. Liquid medium>
The liquid medium for forming the slurry is particularly selected as long as it is a solvent capable of dissolving or dispersing an active material, a conductive material, a binder, and a thickener used as needed. There is no limitation, 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, etc.
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 Amines such as; ethers such as diethyl ether and tetrahydrofuran (THF); amides such as N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide;
Examples thereof include aprotic polar solvents such as hexamethylphosphalamide and dimethylsulfoxide. In addition, these may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

<7. Thickener>
When an aqueous medium is used as the liquid medium for forming the slurry, it is preferable to use a thickener and a latex such as styrene-butadiene rubber (SBR) to form the slurry. Thickeners are typically used to adjust the viscosity of the slurry.

The thickener is not limited as long as the effect of the present invention is not significantly limited, but specifically, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof. And so on. These may be used alone or in combination of two or more in any combination and ratio.

Further, when a thickener is used, it is usually 0.1 part by mass or more, preferably 0.5 part by mass or more, more preferably 0.6 part by mass or more, based on 100 parts by mass of the positive electrode material or the negative electrode material. Further, it is usually 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 2 parts by mass or less. If it is below the above range, the coatability may be significantly reduced, and if it exceeds the above range, the coatability may be significantly reduced.
The ratio of the active material to the active material layer may decrease, which may cause a problem of decreasing the capacity of the battery or an increase in resistance between the active materials.

<8. Current collector>
The material of the 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, tantalum, and copper; and carbonaceous materials such as carbon cloth and carbon paper. Among these, a metal material, particularly aluminum, is preferable.

Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, foamed metal, etc. in the case of metal material, and carbon plate in the case of carbonaceous material. Examples include a carbon thin film and a carbon column. Of these, a metal thin film is preferable.
The thin film may be formed in a mesh shape as appropriate.

The thickness of the current collector is arbitrary, but is usually 1 μm or more, preferably 3 μm or more, and 5 μm or more.
The above is more preferable, and it is usually 1 mm or less, preferably 100 μm or less, and 50 μm or less.
More preferably m or less. When the thin film is within the above range, the strength required as a current collector is maintained.
It is also preferable from the viewpoint of handleability.

<9. Battery design>
[Electrode group]
The electrode group has a laminated structure in which the above-mentioned positive electrode plate and the above-mentioned negative electrode plate are interposed via the above-mentioned separator.
And any of the above-mentioned positive electrode plate and negative electrode plate having a structure in which the above-mentioned positive electrode plate and the negative electrode plate are spirally wound via the above-mentioned separator. 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. When the electrode group occupancy rate is lower than the above range, the battery capacity becomes small.
Further, if it exceeds the above range, the void space is small, and the internal pressure rises due to the expansion of the member due to the high temperature of the battery and the increase of the vapor pressure of the liquid component of the electrolyte, and the charge / discharge repetition performance as a battery. In some cases, various characteristics such as high temperature storage may be deteriorated, and further, a gas release valve that releases internal pressure to the outside may operate.

[Current collector structure]
The current collecting structure is not particularly limited, but in order to more effectively improve the discharge characteristics by the non-aqueous electrolyte solution of the present invention, it is necessary to use a structure that reduces the resistance of the wiring portion and the joint portion. 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-mentioned laminated structure, a structure formed by bundling the metal core portions of each electrode layer and welding them to the terminals is preferably used. When the area of one electrode becomes large, the internal resistance becomes large. Therefore, it is also preferably used to reduce the resistance by providing a plurality of terminals in the electrode. In the case where the electrode group has the above-mentioned winding structure, the internal resistance can be reduced by providing a plurality of lead structures on the positive electrode and the negative electrode and bundling them in the terminals.

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

In the outer case using the metals, the metals are welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed and sealed structure, or the metal is caulked using the metals via a resin gasket. There is something to do. Examples of the outer case using the laminated film include those having a hermetically sealed structure by heat-sealing resin layers to each other.
In order to improve the sealing property, a resin different from the resin used for the laminated film may be interposed between the resin layers. In particular, when the resin layer is heat-sealed via the current collecting terminal to form a closed structure, the metal and the resin are bonded to each other. Resin is preferably used.

[Protective element]
As the above-mentioned protection element, PTC (Po) whose resistance increases when abnormal heat generation or excessive current flows.
Examples include a system Temperature Coefficient), a thermal fuse, a thermistor, and a valve (current cutoff valve) that shuts off the current flowing through the circuit due to a sudden rise in battery internal pressure or internal temperature during abnormal heat generation. It is preferable to select the protective element under conditions that do not operate under normal use with a high current, and from the viewpoint of high output, it is more preferable to design the protective element so as not to cause abnormal heat generation or thermal runaway even without the protective element.

[Exterior body]
The power storage device of the present invention is usually configured by accommodating the above-mentioned non-aqueous electrolyte solution, negative electrode, positive electrode, separator and the like inside the exterior. There are no restrictions on this exterior body, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired.

Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.

Further, the shape of the exterior body is also arbitrary, and may be any of, for example, a cylindrical type, a square shape, a laminated type, a coin type, and a large size.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The structure of the compound represented by the formula (1) used in this example is shown below.

In addition, the structure of other compounds used is shown below.

<Example 1 and Comparative Examples 1 and 2>
[Example 1]
[Preparation of non-aqueous electrolyte solution]
Ethylene carbonate (EC), ethyl methyl carbonate (in a dry argon atmosphere)
Mixed solvent consisting of EMC) and diethyl carbonate (DEC) (mixed volume ratio EC: EM)
LiPF ₆ , which is an electrolyte, was dissolved in C: DEC = 3: 4: 3) at a ratio of 1.2 mol / L. Then, 2.0% by mass of vinylene carbonate (VC) was added to the obtained mixed solution.
In addition, 2.0% by mass of monofluoroethylene carbonate (MFEC) was blended to prepare a basic electrolytic solution. Further, 4.8% by mass of compound (1-1) was added to the basic electrolytic solution to prepare a non-aqueous electrolytic solution of Example 1-1.

[Preparation of positive electrode]
Lithium cobalt oxide (LiCoO ₂ ) 97% by mass as the positive electrode active material, acetylene black 1.5% by mass as the conductive material, and polyvinylidene fluoride (PVdF) as the binder 1.
5% by mass was mixed with a disperser in an N-methylpyrrolidone solvent to form a slurry. This was uniformly applied to both sides of an aluminum foil having a thickness of 15 μm, dried, and then pressed to obtain a positive electrode.

[Manufacturing of negative electrode]
Aqueous dispersion of natural graphite powder as a negative electrode active material, sodium carboxymethyl cellulose as a thickener (concentration of sodium carboxymethyl cellulose 1% by mass), and aqueous dispersion of styrene butadiene rubber as a binder (concentration of styrene butadiene rubber 50% by mass). ) Was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 10 μm, dried, and then pressed to obtain a negative electrode. In the negative electrode after drying, the mass ratio was such that natural graphite: sodium carboxymethyl cellulose: styrene butadiene rubber = 98: 1: 1.

[Manufacturing of lithium secondary battery]
The above positive electrode, negative electrode, and polypropylene separator can be used as the negative electrode, separator, positive electrode, and the like.
A battery element was manufactured by stacking a separator and a negative electrode in this order. This battery element is inserted into a bag made of a laminated film in which both sides of aluminum (thickness 40 μm) are coated with a resin layer while projecting positive and negative terminals, and then a non-aqueous electrolyte solution is injected into the bag. Vacuum sealing was performed to produce a sheet-shaped lithium secondary battery.

[Initial battery characteristic evaluation]
With the lithium secondary battery sandwiched between glass plates and pressurized, the lithium secondary battery is charged at a constant current of 0.05 C for 6 hours at 25 ° C., and then discharged at a constant current of 0.2 C to 3.0 V. The charge / discharge efficiency at this time was defined as the initial charge / discharge efficiency. Further, after constant current-constant voltage charging (also referred to as "CC-CV charging") (0.05C cut) up to 4.1V with a current corresponding to 0.2C, 4
It was left at 5 ° C. for 72 hours. Then, it was discharged to 3.0V with a constant current of 0.2C. Then, after CC-CV charging (0.05C cut) to 4.4V at 0.2C, 0.2.
It was discharged again to 3.0V at C to stabilize the initial battery characteristics. Here, 1C represents a current value for discharging the reference capacity of the battery in 1 hour, and 0.2C represents, for example, a current value of 1/5 of that.

[Evaluation of overcharge characteristics]
A battery for which the capacity and output evaluation test has been completed is charged to 4.1 V at a constant current of 0.3 C at 25 ° C., and then charged to a current value of 0.05 C at a constant voltage of 4.1 V, and then ethanol is used. After immersing in a bath and measuring the volume, a 0.5 C current was applied at 45 ° C. and the current was cut when the SOC 180 was reached, and the open circuit voltage (OCV) of the battery after the overcharge test was measured.
Next, the volume was measured by immersing in an ethanol bath, and the amount of gas generated from the volume change before and after overcharging was determined.

The lower the OCV of the battery after the overcharge test, the lower the overcharge depth and the higher the safety at the time of overcharge. Further, the larger the amount of gas generated after overcharging, the earlier the safety valve can be operated in a battery that detects this when the internal pressure rises abnormally due to an abnormality such as overcharging and activates the safety valve, which is preferable. .. In addition, the larger the difference between the amount of gas generated after overcharging and the amount of gas generated during continuous charging, etc., is to prevent the safety valve from malfunctioning during high-temperature storage, etc., while ensuring that the safety valve operates during overcharging. It is preferable because it can be used.

[Continuous charge durability test]
The lithium secondary battery after the initial evaluation of battery characteristics is CC-CV charged (0.05C cut) at 0.2C to 4.4V at 25 ° C., then immersed in an ethanol bath, and the initial buoyancy at that time is used. The battery volume was calculated. Then, at 60 ° C., constant voltage charging of 4.4 V was performed for 14 days, and the charging current capacity at this time was defined as the continuous charging capacity. Further, a sufficiently cooled battery was immersed in an ethanol bath to measure the volume, and the change from the initial battery volume was taken as the amount of continuous charging gas. Further, at 25 ° C., a constant current was discharged to 3.0 V at 0.2 C. After that, 25 ° C
After CC-CV charging (0.05C cut) to 4.4V with a constant current of 0.2C in
It was discharged again to 3.0V at 0.2C, and this was used as the recovery 0.2C capacity. Further, after CC-CV charging (0.05C cut) to 4.4V at 0.2C, the discharge was made to 3.0V at 0.5C, and this was used as the recovery 0.5C capacity. Then, the ratio of the recovery 0.5C capacity to the recovery 0.2C capacity was obtained, and this was used as the rate characteristic (%) after continuous charging.

[Comparative Example 1]
A lithium secondary battery was produced in the same manner as in Example 1-1 except that the electrolytic solution containing no compound (1-1) was used in the electrolytic solution of Example 1-1, and the above evaluation was carried out.

[Comparative Example 2]
A lithium secondary battery was produced in the same manner as in Example except that 2.0% by mass of compound (2-1) was used instead of compound (1-1) in the electrolytic solution of Example 1, and the above evaluation was performed. Carried out.
The compound (1-1) added in Example 1 and the compound (2-1) added in Comparative Example 2 have the same amount of substance.

As is clear from Table 1, compared with the battery of Comparative Example 1 to which the additive for overcharging was not added,
The battery of Comparative Example 2 has a large amount of gas generated during overcharging and a low OCV after overcharging, so that it is excellent in safety during overcharging, but the capacity is significantly reduced by continuous charging. In the battery using the non-aqueous electrolyte solution of the present invention of Example 1, the amount of gas generated after overcharging is comparable to that of Comparative Example 2, while the OCV after overcharging is low, so that safety during overcharging Can be said to be high. Further, when Example 1 is compared with Comparative Examples 2 and 3, it can be seen that the initial charge / discharge efficiency is comparable and the capacity decrease after continuous charging is suppressed. Therefore, the battery using the non-aqueous electrolyte solution according to the present invention does not significantly impair the battery characteristics by blending the compound represented by the above formula (1), and the safety at the time of overcharging is further improved. You can see that you can.

Claims (5)

A non-aqueous electrolyte solution containing a non-aqueous solvent and a compound represented by the following formula (1).

[In the formula (1), R ¹ to R ¹⁰ are independently hydrogen, halogen, or have 1 or more carbon atoms and 10 or more.
It is a hydrocarbon group that may be substituted with the following halogens. X is halogen, PO (OR ¹ )
¹ ) ₂ , SO ₂ OR ¹² or CN, where R ¹¹ and R ¹² may have substituents, saturated or unsaturated aliphatic hydrocarbons having 1 to 10 carbon atoms. It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have a hydrogen group or a substituent. Y is a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and 2 which may contain a heteroatom.
It is an aromatic hydrocarbon group having 6 to 10 carbon atoms which may have an unsaturated aliphatic hydrocarbon group of 10 to 10 or a substituent. ] The non-aqueous electrolyte solution according to claim 1, wherein the non-aqueous solvent contains 0.001 to 20% by mass of the compound represented by the formula (1). 1 of claim 1, wherein the non-aqueous solvent contains at least one of LiPF ₆ and LiBF ₄ .
Or the non-aqueous electrolyte solution according to 2. At least one of LiPF ₆ and LiBF ₄ is 0.5 to 3.0 in the non-aqueous solvent.
The non-aqueous electrolyte solution according to claim 3, which comprises a concentration of mol / L. A non-aqueous electrolyte battery containing a positive electrode and a negative electrode, and the non-aqueous electrolyte solution according to any one of claims 1 to 4.