JP7342028B2 - Non-aqueous electrolyte and non-aqueous electrolyte battery - Google Patents

Description

The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery, and more particularly to a non-aqueous electrolyte containing a specific compound and a non-aqueous electrolyte battery using this non-aqueous electrolyte.

BACKGROUND ART In recent years, non-aqueous electrolyte batteries such as lithium secondary batteries have been put into practical use as in-vehicle power sources for driving electric vehicles and the like.
As a means of improving the battery characteristics of non-aqueous electrolyte batteries, many studies have been made in the fields of active materials for positive and negative electrodes and additives for non-aqueous electrolytes.
For example, Patent Document 1 discloses a study in which self-discharge during storage is suppressed and storage characteristics are improved by incorporating an isocyanuric acid derivative into a non-aqueous electrolytic solution.

Japanese Patent Application Publication No. 7-192757

In recent years, the capacity of lithium secondary batteries used as on-vehicle power supplies for electric vehicles has been increasing at an accelerated pace, and the number of voids other than those for constituent members in a battery case is decreasing. Therefore, the battery swells due to the gas generated during high-temperature storage. Furthermore, since the amount of electrolyte in the battery is also reduced, the amount of repair component is reduced when, for example, a film deposited on the electrode is eluted due to high temperature storage. Therefore, when the coating is eluted, there are two problems: the thickness of the coating increases due to continuous decomposition reactions of the electrolytic solution, and the resistance of the battery increases. Therefore, it is important to suppress not only the generation of gas during high-temperature storage but also the increase in resistance of the battery.

However, according to studies by the present inventors, when an electrolytic solution containing an isocyanuric acid compound having a polymerizable functional group in the molecule disclosed in Patent Document 1 is used, gas generation during high-temperature storage is suppressed; It has been found that non-aqueous electrolyte batteries have a problem of increased battery resistance.

As a result of various studies to achieve the above object, the present inventors discovered that the above problem could be solved by incorporating a specific compound into the electrolytic solution, and thus completed the present invention. . The present invention provides the following aspects.
[1] A non-aqueous electrolyte containing a compound represented by the following general formula (A).

(In formula (A), R ¹ to R ⁴ each independently represent a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and X may have a substituent. (Indicates an alkylene group having 1 to 12 carbon atoms.)
[2] The non-aqueous system according to [1], wherein in the general formula (A), at least one of R ¹ to R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms and having a carbon-carbon unsaturated bond. Electrolyte.
[3] The non-aqueous electrolyte according to [2], wherein the hydrocarbon group having 1 to 12 carbon atoms and having a carbon-carbon unsaturated bond is an allyl group or a methallyl group.
[4] The content of the compound represented by the general formula (A) is 0.001% by mass or more and 10% by mass or less based on the total amount of the non-aqueous electrolyte, [1] to [3] The non-aqueous electrolyte according to any one of the above.
[5] The nonaqueous electrolyte is a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a compound having a cyano group, a diisocyanate compound, a cyclic sulfonic acid ester, a fluorinated salt, and an oxalate salt. The non-aqueous electrolyte according to any one of [1] to [4], which contains at least one compound selected from Group W consisting of:
[6] A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte according to any one of [1] to [5]. A non-aqueous electrolyte battery.
[7] The non-aqueous electrolyte battery according to [6], wherein the negative electrode includes a negative electrode active material, and the negative electrode active material contains carbon.
[8] The nonaqueous electrolyte battery according to [6], wherein the negative electrode includes a negative electrode active material, and the negative electrode active material contains silicon (Si) or tin (Sn).
[9] The negative electrode includes a negative electrode active material, and the negative electrode active material is a mixture and/or composite of graphite particles and particles containing silicon (Si) or tin (Sn). Non-aqueous electrolyte battery.
[10] The nonaqueous system according to any one of [6] to [9], wherein the positive electrode contains a positive electrode active material, and the positive electrode active material contains a metal oxide represented by the following composition formula (1). electrolyte battery.

Li _a1 Ni _b1 Co _c1 M _d1 O ₂ ...(1)
(In the above formula (1), a1, b1, c1 and d1 are 0.90≦a1≦1.10, 0.50≦b1≦0.98, 0.01≦c1<0.50, 0.01 Indicates a numerical value of ≦d1<0.50, and satisfies b1+c1+d1=1.M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er.)

The present invention also provides a non-aqueous electrolyte that can suppress not only gas generation during high-temperature storage but also an increase in internal resistance (hereinafter simply referred to as battery resistance) of a non-aqueous electrolyte battery. An electrolyte battery can be provided.

Embodiments of the present invention will be described in detail below. The following embodiments are examples (representative examples) of the embodiments of the present invention, and the present invention is not limited thereto. Moreover, the present invention can be implemented with arbitrary changes within the scope without departing from the gist thereof.
<1. Non-aqueous electrolyte>
<1-1. Compound represented by general formula (A)>
A non-aqueous electrolytic solution according to one embodiment of the present invention contains a compound represented by the following general formula (A).

In formula (A), R ¹ to R ⁴ each independently represent a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and X is a carbon atom which may have a substituent. Indicates an alkylene group having numbers 1 to 12.
Here, the substituents include a cyano group, an isocyanato group, an acyl group (-(C=O)-Ra), an acyloxy group (-O(C=O)-Ra), an alkoxycarbonyl group (-(C= O)O-Ra), sulfonyl group (-SO ₂ -Ra), sulfonyloxy group (-O(SO ₂ )-Ra), alkoxysulfonyl group (-(SO ₂ )-O-Ra), alkoxycarbonyloxy group (-O-(C=O)-O-Ra), ether group (-O-Ra), acrylic group, methacryl group, halogen (preferably fluorine), trifluoromethyl group, and the like. Note that Ra represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. Specific examples of Ra include those described below.

Among these substituents, preferred are a cyano group, an isocyanato group, an acyloxy group (-O(C=O)-Ra), an alkoxycarbonyl group (-(C=O)O-Ra), and a sulfonyl group (-SO ₂ -Ra), a sulfonyloxy group (-O(SO ₂ )-Ra), an alkoxysulfonyl group (-(SO ₂ )-O-Ra), an acrylic group, or a methacryl group.

Specific examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, and an aryl group which may have an alkylene group interposed therebetween. Among these, an alkyl group, an alkenyl group, or an alkynyl group is preferred, an alkenyl group or an alkynyl group is more preferred, and an alkenyl group is particularly preferred.

Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, i-butyl group, t-butyl group, n-pentyl group, Examples include t-amyl group, hexyl group, heptyl group, octyl group, nonyl group, and decyl group. Among these, preferred are ethyl group, n-propyl group, n-butyl group, n-pentyl group, or hexyl group, and more preferred are ethyl group, n-propyl group, or n-butyl group.

Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and an adamantyl group, with a cyclohexyl group or an adamantyl group being preferred.
Specific examples of the alkenyl group include vinyl group, allyl group, methallyl group, 2-butenyl group, 3-methyl-2-butenyl group, 3-butenyl group, and 4-pentenyl group. Among these, vinyl group, allyl group, methallyl group or 2-butenyl group are preferred, vinyl group, allyl group or methallyl group is more preferred, allyl group or methallyl group is particularly preferred, and most preferred is vinyl group, allyl group or methallyl group. Preferably it is an allyl group. This is because when the hydrocarbon group is such an alkenyl group, steric hindrance is appropriate and the increase in electrode resistance caused by the reaction of the compound of general formula (A) on the electrode can be adjusted to a suitable degree. be.

Specific examples of the alkynyl group include ethynyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, 4-pentynyl group, 5-hexynyl group, and the like. Among these, preferred are ethynyl group, 2-propynyl group, 2-butynyl group, or 3-butynyl group, more preferred are 2-propynyl group or 3-butynyl group, and particularly preferred are 2-propynyl group. It is. This is because when the hydrocarbon group is such an alkynyl group, steric hindrance is appropriate and the increase in electrode resistance due to the reaction of the compound of general formula (A) on the electrode can be adjusted to a suitable level. .

Specific examples of the aryl group which may be interposed through the alkylene group include phenyl group, tolyl group, benzyl group, phenethyl group, and the like.

The R ¹ to R ⁴ are preferably an alkyl group, an allyl group, or a methallyl group which may have a substituent, and an allyl group is particularly preferable from the viewpoint of film-forming ability.
Further, at least one of R ¹ to R ⁴ is preferably a hydrocarbon group having 1 to 12 carbon atoms and having a carbon-carbon unsaturated bond. The hydrocarbon group having a carbon-carbon unsaturated bond may have a carbon-carbon unsaturated bond in a substituent, preferably includes a group having a carbon-carbon unsaturated bond at the terminal, and more preferably allyl. , a methallyl group, and a butenyl group, and more preferably an allyl group or a methallyl group.

Further, R ¹ to R ⁴ may be the same or different, but preferably R ¹ and R ² are the same group or R ³ and R ⁴ are the same group, and more preferably R ¹ and R ² are the same group, and R ³ and R ⁴ are the same group, particularly preferably all of R ¹ to R ⁴ are the same group. When R ¹ and R ² are the same group and/or R ³ and R ⁴ are the same group, the compound represented by the general formula (A) reacts uniformly on the negative electrode, forming an insulating film. It is preferable because it can be formed suitably.
The number of carbon atoms in X is preferably 2 to 8, more preferably 2 to 6. Examples of the substituent that X may have include the same substituents as the substituents that a hydrocarbon group may have, and preferred substituents are also the same groups, but the above-mentioned X has no substituent. It is preferable not to have it.

Specific examples of the compound represented by the general formula (A) used in this embodiment include compounds having the following structures.

Among the compounds represented by the general formula (A), compounds having the following structures are preferably mentioned.

More preferable examples of the compound represented by the general formula (A) include compounds having the following structures.

Particularly preferred examples of the compound represented by the general formula (A) include compounds having the following structures.

The compound represented by the general formula (A) is most preferably a compound having the following structure.

The compounds represented by the general formula (A) used in this embodiment may be used alone or in combination of two or more in any combination and ratio.
The content of the compound represented by general formula (A) in the entire nonaqueous electrolyte of this embodiment is usually 0.001% by mass or more, preferably 0.01% by mass or more in 100% by mass of the nonaqueous electrolyte. , more preferably 0.05% by mass or more, and usually 10% by mass or less, preferably 2.00% by mass or less, more preferably 1.50% by mass or less, still more preferably 1.00% by mass or less, Particularly preferably 0.75% by mass or less, most preferably 0.60% by mass or less. If the content of the compound represented by general formula (A) is within this range, not only can gas generation during high-temperature storage be suppressed, but also an increase in battery resistance can be suppressed. A method for measuring the content of the compound represented by the general formula (A) in the non-aqueous electrolyte includes, for example, ¹ H-NMR.

Although the mechanism by which the use of a non-aqueous electrolyte containing the compound represented by general formula (A) not only suppresses gas generation during high-temperature storage but also suppresses increases in battery resistance is not clear, it is explained below. I guess.
The lithium salt, which is a component of the non-aqueous electrolyte, and the carbonate compound, which is a solvent, electrochemically react with the negative electrode during initial charging, and a decomposition reaction progresses. Since the compound represented by the general formula (A) has a site within its structure that reacts with these reductive decomposition products, a composite consisting of the compound represented by the general formula (A) and the decomposition products of the electrolyte components is placed on the negative electrode. Forms a protective film. Since this coating has high insulation properties at high temperatures, it suppresses side reactions at the negative electrode during high-temperature storage and suppresses gas generation. In addition, in conventionally used isocyanuric acid compounds that have a polymerizable functional group in the molecule, such as that described in Patent Document 1, the reaction does not proceed sufficiently during the first charge, and reactive sites within the structure remain. If so, it is thought that the reaction between the reductive decomposition product of the electrolyte and the remaining reaction sites proceeds excessively during high-temperature storage, resulting in an increase in battery resistance. On the other hand, the compound represented by the general formula (A) has an alkylene chain between units that are reactive with the reductive decomposition product, so even if the reaction does not proceed sufficiently during the initial charging, the reaction within the structure may occur. Even if some portions remain, it is presumed that the film-forming reaction progressed uniformly during the high-temperature storage test, successfully suppressing local increases in resistance. It is presumed that this made it possible not only to suppress gas generation during high-temperature storage, but also to suppress an increase in battery resistance.

The method for producing the compound represented by the general formula (A) is not particularly limited, and it can be produced by a known method, such as the method disclosed in JP-A No. 2015-151413.
Note that there are no particular restrictions on the method of incorporating the compound represented by general formula (A) into the non-aqueous electrolyte of this embodiment. In addition to the method of directly adding the above compound to the electrolyte, there is a method of generating the above compound in the battery or in the electrolyte.
In this embodiment, the content of the compound represented by general formula (A) refers to the content at the time of manufacturing the non-aqueous electrolyte, the time of injecting the non-aqueous electrolyte into the battery, or the time of shipping the battery. means the content of

<1-2. Additive>
The non-aqueous electrolyte of the present embodiment may contain various additives as long as the effects of the present invention are not significantly impaired. Any conventionally known additives can be used as the additive. One type of additive may be used alone, or two or more types may be used in combination in any combination and ratio.
As additives, among others, cyclic carbonates having a carbon-carbon unsaturated bond, cyclic carbonates having a fluorine atom, compounds having a cyano group, diisocyanate compounds, cyclic sulfonic acid esters, fluorinated salts and oxalate salts are used. At least one compound selected from group W is preferred.

<1-2-1. Cyclic carbonate with carbon-carbon unsaturated bond>
The cyclic carbonate having a carbon-carbon unsaturated bond in Group W (hereinafter sometimes referred to as "unsaturated cyclic carbonate") is a cyclic carbonate having a carbon-carbon double bond or a carbon-carbon triple bond. If so, any unsaturated cyclic carbonate can be used without any particular limitation. Note that cyclic carbonates having aromatic rings are also included in unsaturated cyclic carbonates.

Examples of unsaturated cyclic carbonates include vinylene carbonates; ethylene carbonates substituted with a substituent having an aromatic ring, a carbon-carbon double bond, or a carbon-carbon triple bond; cyclic carbonates having a phenyl group; having a vinyl group Examples include cyclic carbonates; cyclic carbonates having an allyl group; cyclic carbonates having a catechol group; and the like. Preferred are vinylene carbonates; ethylene carbonates having a vinyl group; ethylene carbonates having an allyl group; and ethylene carbonates having a phenyl group.

As vinylene carbonates,
Vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-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, etc. .

Specific examples of ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds or carbon-carbon triple bonds include:
Vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-diethynyl ethylene carbonate, 4-methyl-5 -Ethynylethylene carbonate, 4-vinyl-5-ethynylethylene carbonate, 4-allyl-5-ethynylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl -5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate and the like.

Among these, preferable unsaturated cyclic carbonates are:
Vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-divinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate , 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5 -diethynylethylene carbonate, 4-methyl-5-ethynylethylene carbonate, and 4-vinyl-5-ethynylethylene carbonate.

Furthermore, vinylene carbonate, vinyl ethylene carbonate, and ethynyl ethylene carbonate are particularly preferred since they form a more stable interfacial protective film.
The molecular weight of the unsaturated cyclic carbonate is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the present invention. The molecular weight is preferably 80 or more, more preferably 85 or more, and preferably 250 or less, more preferably 150 or less. Within this range, the solubility of the unsaturated cyclic carbonate in the non-aqueous electrolyte can be easily ensured, and the effects of the present invention can be fully exhibited. The method for producing the unsaturated cyclic carbonate is not particularly limited, and any known method can be selected to produce the unsaturated cyclic carbonate. Alternatively, commercially available products may be obtained and used.

One type of unsaturated cyclic carbonate may be used alone, or two or more types may be used in combination in any combination and ratio. Further, the content of the unsaturated cyclic carbonate in the entire non-aqueous electrolyte of the present embodiment is preferably 0.01% by mass or more, more preferably 0.1% by mass or more based on 100% by mass of the non-aqueous electrolyte. , and is 5.0% by mass or less, preferably 4.0% by mass or less, more preferably 3.0% by mass or less, particularly preferably 2.0% by mass or less. If the content of unsaturated cyclic carbonate is within this range, it is easy to avoid a situation where battery resistance increases during high temperature storage. When two or more types of unsaturated cyclic carbonates are used in combination, the total amount of the unsaturated cyclic carbonates may satisfy the above range.

<1-2-2. Cyclic carbonate with fluorine atom>
Examples of the cyclic carbonate having a fluorine atom in Group W include fluorinated cyclic carbonates having an alkylene group having 2 to 6 carbon atoms and derivatives thereof, such as fluorinated ethylene carbonate and derivatives thereof. . Examples of fluorinated ethylene carbonate derivatives include fluorinated ethylene carbonate substituted with an alkyl group (eg, an alkyl group having 1 to 4 carbon atoms). Among these, ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferred.

in particular,
Monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methyl Ethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate, 4-(trifluoromethyl)-ethylene carbonate, 4-(fluoromethyl)-ethylene carbonate methyl)-4-fluoroethylene carbonate, 4-(fluoromethyl)-5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene carbonate, 4, Examples include 4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate imparts high ionic conductivity to the nonaqueous electrolyte and also provides suitable interface protection. It is more preferred in terms of forming a film.

The cyclic carbonate compounds having a fluorine atom may be used alone or in combination of two or more in any combination and ratio. Embodiment There is no limit to the content of the cyclic carbonate having a fluorine atom in the entire non-aqueous electrolyte, and it is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 0.001 mass% in 100 mass% of the non-aqueous electrolyte. % or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 1% by mass or more, and usually 50.0% by mass. The content is preferably 30.0% by mass or less, more preferably 20.0% by mass or less, even more preferably 10.0% by mass or less. When using two or more types of cyclic carbonate compounds having a fluorine atom, the total amount of the cyclic carbonate compounds having a fluorine atom may satisfy the above range.

<1-2-3. Compounds having a cyano group>
The compound having a cyano group in Group W is not particularly limited in type as long as it has a cyano group in the molecule, but a compound represented by the following general formula (11) is more preferable. The method for producing a compound having a cyano group is not particularly limited, and any known method can be selected for production.

In general formula (11), T represents an organic group composed of atoms selected from the group consisting of carbon atom, nitrogen atom, oxygen atom, sulfur atom, and phosphorus atom, and U even if it has a substituent. It is a good V-valent organic group having 1 to 10 carbon atoms. V is an integer of 1 or more, and when V is 2 or more, T may be the same or different.
The molecular weight of the compound having a cyano group is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the present invention. The molecular weight of the compound having a cyano group is usually 40 or more, preferably 45 or more, more preferably 50 or more, and usually 200 or less, preferably 180 or less, more preferably 170 or less. If the molecular weight of the compound having a cyano group is within this range, the solubility of the compound having a cyano group in the nonaqueous electrolyte can be easily ensured, and the effects of the present invention can be easily exhibited.

Specific examples of the compound represented by the general formula (11) include acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile. , hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitrile, 2-pentenenitrile, 2-methyl-2 -Pentenenitrile, 3-methyl-2-pentenenitrile, 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile , 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3,3'-oxydipropionitrile , 3,3'-thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, a compound having one cyano group such as pentafluoropropionitrile;

Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelanitrile, sebaconitrile, undecanedinitrile, dodecanedinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononitrile, methylsuccinonitrile , 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, trimethylsuccinonitrile, tetramethylsuccinonitrile, 3,3'-(ethylenedioxy)dipropionitrile, 3,3'-( Compounds having two cyano groups such as ethylenedithio)dipropionitrile;
Compounds having three cyano groups such as 1,2,3-tris(2-cyanoethoxy)propane and tris(2-cyanoethyl)amine;

Cyanate compounds such as methyl cyanate, ethyl cyanate, propyl cyanate, butyl cyanate, pentyl cyanate, hexyl cyanate, heptyl cyanate;
Methyl thiocyanate, ethyl thiocyanate, propyl thiocyanate, butyl thiocyanate, pentyl thiocyanate, hexyl thiocyanate, heptyl thiocyanate, methanesulfonyl cyanide, ethanesulfonyl cyanide, propanesulfonyl cyanide, butanesulfonyl cyanide, pentanesulfonyl cyanide, hexane sulfonyl cyanide , heptanesulfonyl cyanide, methylsulfurocyanidate, ethylsulfurocyanidate, propylsulfurocyanidate, butylsulfurocyanidate, pentylsulfurocyanidate, hexylsulfurocyanidate, heptylsulfurocyanidate Sulfur-containing compounds such as furocyanidate;

Cyanodimethylphosphine, cyanodimethylphosphine oxide, methyl cyanomethylphosphine, methyl cyanomethylphosphinate, dimethylphosphinic acid cyanide, dimethylphosphinic acid cyanide, dimethyl cyanophosphonate, dimethyl cyanophosphonite, cyanomethyl methylphosphonate, methylphosphonite Phosphorus-containing compounds such as cyanomethyl acid, cyanodimethyl phosphate and cyanodimethyl phosphite;
etc.

Among these, acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, Pimeronitrile, suberonitrile, azelanitrile, sebaconitrile, undecane dinitrile, and dodecane dinitrile are preferred from the viewpoint of improving storage properties, and malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azelanitrile, sebaconitrile, undecane dinitrile, and dodecane dinitrile are preferred. More preferred are compounds having two cyano groups such as nitrile.

The compounds having a cyano group may be used alone or in combination of two or more in any ratio. There is no limit to the content of the compound having a cyano group in the entire non-aqueous electrolytic solution of this embodiment, and it is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 0.001% in the non-aqueous electrolytic solution. Mass % or more, preferably 0.01 mass % or more, more preferably 0.1 mass % or more, even more preferably 0.3 mass % or more, and usually 10 mass % or less, preferably 5 mass % or less, more preferably is contained at a concentration of 3% by mass or less. When the above range is satisfied, effects such as low-temperature output characteristics, charge/discharge rate characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

<1-2-4. Diisocyanate compound>
As the diisocyanate compound in the above group W, a compound having a nitrogen atom only in the isocyanato group or two isocyanato groups in the molecule and represented by the following general formula (12) is preferable.

In the above general formula (12), Y is an organic group containing a cyclic structure and having 2 or more and 15 or less carbon atoms. The carbon number of Y is usually 2 or more, preferably 3 or more, more preferably 4 or more, and usually 15 or less, preferably 14 or less, more preferably 12 or less, still more preferably 10 or less, particularly preferably 8 It is as follows.
In the above general formula (12), Y is particularly preferably an organic group having 4 to 15 carbon atoms and having one or more cycloalkylene groups having 4 to 6 carbon atoms or one or more aromatic hydrocarbon groups. At this time, the hydrogen atom on the cycloalkylene group may be substituted with a methyl group or an ethyl group. Since the diisocyanate compound having a cyclic structure is a sterically bulky molecule, side reactions on the positive electrode are less likely to occur, and as a result, cycle characteristics and high temperature storage characteristics are improved.

The bonding site of the group bonding to the cycloalkylene group or aromatic hydrocarbon group is not particularly limited, and may be any of the meta, para, or ortho positions. This is preferable because it is advantageous for lithium ion conductivity and makes it easier to reduce resistance. In addition, it is preferable that the cycloalkylene group is a cyclopentylene group or a cyclohexylene group from the viewpoint that the diisocyanate compound itself is less likely to cause side reactions, and a cyclohexylene group is preferable because it reduces resistance due to the influence of molecular mobility. It is more preferable because it is easy to reduce the amount.

Further, it is preferable that an alkylene group having 1 to 3 carbon atoms is present between the cycloalkylene group or aromatic hydrocarbon group and the isocyanato group. Having an alkylene group increases steric bulk, making side reactions less likely to occur on the positive electrode. Furthermore, if the alkylene group has 1 to 3 carbon atoms, the ratio of isocyanato groups to the total molecular weight does not change significantly, making it easier to achieve the effects of the present invention.

The molecular weight of the diisocyanate compound represented by the above general formula (12) is not particularly limited, and may be arbitrary as long as it does not significantly impair the effects of the present invention. The molecular weight is usually 80 or more, preferably 115 or more, more preferably 170 or more, and usually 300 or less, preferably 230 or less. If the molecular weight of the diisocyanate compound is within this range, the solubility of the diisocyanate compound in the non-aqueous electrolyte can be easily ensured, and the effects of the present invention can be easily exhibited.

Specific examples of diisocyanate compounds include 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1, 4-diisocyanatocyclohexane, 1,2-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-2,2' - cycloalkane ring-containing diisocyanates such as diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate;

1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene-2,3-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,5-diisocyanate, tolylene-2,6 -diisocyanate, tolylene-3,4-diisocyanate, tolylene-3,5-diisocyanate, 1,2-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)benzene, 1,4-bis(isocyanatomethyl)benzene (natomethyl)benzene, 2,4-diisocyanatobiphenyl, 2,6-diisocyanatobiphenyl, 2,2'-diisocyanatobiphenyl, 3,3'-diisocyanatobiphenyl, 4,4'-diisocyanato- 2-methylbiphenyl, 4,4'-diisocyanato-3-methylbiphenyl, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, 4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanato-2 -Methyldiphenylmethane, 4,4'-diisocyanato-3-methyldiphenylmethane, 4,4'-diisocyanato-3,3'-dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, 1,8-diisocyanatonaphthalene, 2 , 3-diisocyanatonaphthalene, 1,5-bis(isocyanatomethyl)naphthalene, 1,8-bis(isocyanatomethyl)naphthalene, 2,3-bis(isocyanatomethyl)naphthalene, and other aromatic ring-containing diisocyanates. ; etc.

Among these, 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane , 1,2-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate , 1,4-phenylene diisocyanate, 1,2-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)benzene, 1,4-bis(isocyanatomethyl)benzene, 2,4-diisocyanate Natobiphenyl and 2,6-diisocyanatobiphenyl are preferred because they form a denser composite film on the negative electrode, resulting in improved battery durability.

Among these, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, Methyl)benzene, 1,3-bis(isocyanatomethyl)benzene, and 1,4-bis(isocyanatomethyl)benzene form a film on the negative electrode that is advantageous for lithium ion conductivity due to the symmetry of their molecules. As a result, battery characteristics such as low-temperature output characteristics and cycle characteristics are further improved, which is more preferable.

Moreover, the above-mentioned diisocyanate compounds may be used alone or in combination of two or more in any combination and ratio.
In the non-aqueous electrolytic solution of the present embodiment, the content of the diisocyanate compound is not particularly limited and may be arbitrary as long as it does not significantly impair the effects of the present invention. Usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and usually 5% by mass or less, preferably 4% by mass. The content is more preferably 3% by mass or less, further preferably 2% by mass or less. When the content of the diisocyanate compound is within the above range, battery characteristics such as low-temperature output and cycle characteristics tend to be further improved.
Note that the method for producing the diisocyanate compound is not particularly limited, and any known method can be selected to produce the diisocyanate compound. Alternatively, commercially available products may be used.

<1-2-5. Cyclic sulfonic acid ester>
The type of the cyclic sulfonic acid ester in Group W is not particularly limited.
Specific examples of cyclic sulfonic acid esters include, for example,
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-methyl-1,3-propane sultone , 2-methyl-1,3-propane sultone, 3-methyl-1,3-propane sultone, 1-propene-1,3-sultone, 2-propene-1,3-sultone, 1-fluoro-1-propene -1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1-fluoro-2-propene-1,3-sultone, 2 -Fluoro-2-propene-1,3-sultone, 3-fluoro-2-propene-1,3-sultone, 1-methyl-1-propene-1,3-sultone, 2-methyl-1-propene-1 ,3-sultone, 3-methyl-1-propene-1,3-sultone, 1-methyl-2-propene-1,3-sultone, 2-methyl-2-propene-1,3-sultone, 3-methyl -2-propene-1,3-sultone, 1,4-butanesultone, 1-fluoro-1,4-butanesultone, 2-fluoro-1,4-butanesultone, 3-fluoro-1,4-butanesultone, 4-fluoro -1,4-butanesultone, 1-methyl-1,4-butanesultone, 2-methyl-1,4-butanesultone, 3-methyl-1,4-butanesultone, 4-methyl-1,4-butanesultone, 1-butene -1,4-sultone, 2-butene-1,4-sultone, 3-butene-1,4-sultone, 1-fluoro-1-butene-1,4-sultone, 2-fluoro-1-butene-1 , 4-sultone, 3-fluoro-1-butene-1,4-sultone, 4-fluoro-1-butene-1,4-sultone, 1-fluoro-2-butene-1,4-sultone, 2-fluoro -2-butene-1,4-sultone, 3-fluoro-2-butene-1,4-sultone, 4-fluoro-2-butene-1,4-sultone, 1-fluoro-3-butene-1,4 -sultone, 2-fluoro-3-butene-1,4-sultone, 3-fluoro-3-butene-1,4-sultone, 4-fluoro-3-butene-1,4-sultone, 1-methyl-1 -Butene-1,4-sultone, 2-methyl-1-butene-1,4-sultone, 3-methyl-1-butene-1,4-sultone, 4-methyl-1-butene-1,4-sultone , 1-methyl-2-butene-1,4-sultone, 2-methyl-2-butene-1,4-sultone, 3-methyl-2-butene-1,4-sultone, 4-methyl-2-butene -1,4-sultone, 1-methyl-3-butene-1,4-sultone, 2-methyl-3-butene-1,4-sultone, 3-methyl-3-butene-1,4-sultone, 4 -Methyl-3-butene-1,4-sultone, 1,5-pentane sultone, 1-fluoro-1,5-pentane sultone, 2-fluoro-1,5-pentane sultone, 3-fluoro-1,5- Pentane sultone, 4-fluoro-1,5-pentane sultone, 5-fluoro-1,5-pentane sultone, 1-methyl-1,5-pentane sultone, 2-methyl-1,5-pentane sultone, 3-methyl -1,5-pentane sultone, 4-methyl-1,5-pentane sultone, 5-methyl-1,5-pentane sultone, 1-pentene-1,5-sultone, 2-pentene-1,5-sultone, 3-pentene-1,5-sultone, 4-pentene-1,5-sultone, 1-fluoro-1-pentene-1,5-sultone, 2-fluoro-1-pentene-1,5-sultone, 3- Fluoro-1-pentene-1,5-sultone, 4-fluoro-1-pentene-1,5-sultone, 5-fluoro-1-pentene-1,5-sultone, 1-fluoro-2-pentene-1, 5-sultone, 2-fluoro-2-pentene-1,5-sultone, 3-fluoro-2-pentene-1,5-sultone, 4-fluoro-2-pentene-1,5-sultone, 5-fluoro- 2-Pentene-1,5-sultone, 1-fluoro-3-pentene-1,5-sultone, 2-fluoro-3-pentene-1,5-sultone, 3-fluoro-3-pentene-1,5- Sulton, 4-fluoro-3-pentene-1,5-sultone, 5-fluoro-3-pentene-1,5-sultone, 1-fluoro-4-pentene-1,5-sultone, 2-fluoro-4- Pentene-1,5-sultone, 3-fluoro-4-pentene-1,5-sultone, 4-fluoro-4-pentene-1,5-sultone, 5-fluoro-4-pentene-1,5-sultone, 1-Methyl-1-pentene-1,5-sultone, 2-methyl-1-pentene-1,5-sultone, 3-methyl-1-pentene-1,5-sultone, 4-methyl-1-pentene- 1,5-sultone, 5-methyl-1-pentene-1,5-sultone, 1-methyl-2-pentene-1,5-sultone, 2-methyl-2-pentene-1,5-sultone, 3- Methyl-2-pentene-1,5-sultone, 4-methyl-2-pentene-1,5-sultone, 5-methyl-2-pentene-1,5-sultone, 1-methyl-3-pentene-1, 5-sultone, 2-methyl-3-pentene-1,5-sultone, 3-methyl-3-pentene-1,5-sultone, 4-methyl-3-pentene-1,5-sultone, 5-methyl- 3-pentene-1,5-sultone, 1-methyl-4-pentene-1,5-sultone, 2-methyl-4-pentene-1,5-sultone, 3-methyl-4-pentene-1,5- sultone compounds such as sultone, 4-methyl-4-pentene-1,5-sultone, and 5-methyl-4-pentene-1,5-sultone;

Sulfate compounds such as methylene sulfate, ethylene sulfate, propylene sulfate;
Disulfonate compounds such as methylenemethanedisulfonate and ethylenemethanedisulfonate;
1,2,3-oxathiazolidine-2,2-dioxide, 3-methyl-1,2,3-oxathiazolidine-2,2-dioxide, 3H-1,2,3-oxathiazole-2,2-dioxide , 5H-1,2,3-oxathiazole-2,2-dioxide, 1,2,4-oxathiazolidine-2,2-dioxide, 4-methyl-1,2,4-oxathiazolidine-2,2- Dioxide, 3H-1,2,4-oxathiazole-2,2-dioxide, 5H-1,2,4-oxathiazole-2,2-dioxide, 1,2,5-oxathiazolidine-2,2-dioxide , 5-methyl-1,2,5-oxathiazolidine-2,2-dioxide, 3H-1,2,5-oxathiazole-2,2-dioxide, 5H-1,2,5-oxathiazole-2, 2-dioxide, 1,2,3-oxathiazinane-2,2-dioxide, 3-methyl-1,2,3-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,3-oxathiazine- 2,2-dioxide, 1,2,4-oxathiazinane-2,2-dioxide, 4-methyl-1,2,4-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,4- Oxathiazine-2,2-dioxide, 3,6-dihydro-1,2,4-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,4-oxathiazine-2,2-dioxide, 1, 2,5-oxathiazinane-2,2-dioxide, 5-methyl-1,2,5-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,5-oxathiazine-2,2-dioxide, 3,6-dihydro-1,2,5-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,5-oxathiazine-2,2-dioxide, 1,2,6-oxathiazinane-2, 2-dioxide, 6-methyl-1,2,6-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide, 3,4-dihydro-1, Nitrogen-containing compounds such as 2,6-oxathiazine-2,2-dioxide and 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide;

1,2,3-oxathiaphosphorane-2,2-dioxide, 3-methyl-1,2,3-oxathiaphosphorane-2,2-dioxide, 3-methyl-1,2,3-oxathia Phosphorane-2,2,3-trioxide, 3-methoxy-1,2,3-oxathiaphosphorane-2,2,3-trioxide, 1,2,4-oxathiaphosphorane-2,2-dioxide , 4-methyl-1,2,4-oxathiaphosphorane-2,2-dioxide, 4-methyl-1,2,4-oxathiaphosphorane-2,2,4-trioxide, 4-methoxy-1 , 2,4-oxathiaphosphorane-2,2,4-trioxide, 1,2,5-oxathiaphosphorane-2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphorane- 2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphorane-2,2,5-trioxide, 5-methoxy-1,2,5-oxathiaphosphorane-2,2,5- trioxide, 1,2,3-oxathiaphosphinane-2,2-dioxide, 3-methyl-1,2,3-oxathiaphosphinane-2,2-dioxide, 3-methyl-1,2,3- Oxathiaphosphinane-2,2,3-trioxide, 3-methoxy-1,2,3-oxathiaphosphinane-2,2,3-trioxide, 1,2,4-oxathiaphosphinane-2,2 -dioxide, 4-methyl-1,2,4-oxathiaphosphinane-2,2-dioxide, 4-methyl-1,2,4-oxathiaphosphinane-2,2,3-trioxide, 4-methyl -1,5,2,4-dioxathiophosphinane-2,4-dioxide, 4-methoxy-1,5,2,4-dioxathiophosphinane-2,4-dioxide, 3-methoxy-1 , 2,4-oxathiaphosphinane-2,2,3-trioxide, 1,2,5-oxathiaphosphinane-2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphinane- 2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphinane-2,2,3-trioxide, 5-methoxy-1,2,5-oxathiaphosphinane-2,2,3- trioxide, 1,2,6-oxathiaphosphinane-2,2-dioxide, 6-methyl-1,2,6-oxathiaphosphinane-2,2-dioxide, 6-methyl-1,2,6- Phosphorus-containing compounds such as oxathiaphosphinane-2,2,3-trioxide and 6-methoxy-1,2,6-oxathiaphosphinane-2,2,3-trioxide;
can be mentioned.

Among these, 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-propene-1, 3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1,4- Butane sultone, methylene methane disulfonate, and ethylene methane disulfonate are preferred from the viewpoint of improving the storage properties of the non-aqueous electrolyte.
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-propene-1,3-sultone, More preferred is methylenemethane disulfonate.

One type of cyclic sulfonic acid ester may be used alone, or two or more types may be used together in any combination and ratio. The content of the cyclic sulfonic acid ester in the entire non-aqueous electrolyte of the present embodiment is not particularly limited and may be arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 0.001% in 100% by mass of the non-aqueous electrolyte. At least 10% by mass, preferably at least 0.01% by mass, more preferably at least 0.1% by mass, and usually at most 10% by mass, preferably at most 5% by mass, more preferably at most 3% by mass, particularly preferably at most 3% by mass. is 2% by mass or less, most preferably 1% by mass or less. When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics of the nonaqueous electrolyte battery are further improved.

<1-2-6. Fluorinated salt>
The fluorinated salt in Group W is not particularly limited, but since it has a highly eliminable fluorine atom in its structure, for example, the compound represented by general formula (A) may undergo a reduction reaction. A difluorophosphate, a fluorosulfonate, or a salt having a bisfluorosulfonylimide structure is preferred because it can react favorably with the generated anion (nucleophilic species) and form a composite film. Difluorophosphates or fluorosulfonates are more preferred because they have a particularly high ability to eliminate fluorine atoms and their reactions with nucleophiles proceed favorably. These various salts will be explained below.

<<Difluorophosphate>>
Counter cations of difluorophosphate are not particularly limited, but include 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 represents a hydrogen atom or an organic group having 1 to 12 carbon atoms.

The organic group having 1 to 12 carbon atoms represented by R ¹³ to R ¹⁶ of the above ammonium is not particularly limited, but for example, an alkyl group that may be substituted with a halogen atom, a halogen atom, or an alkyl group substituted with a halogen atom. Examples include a cycloalkyl group which may be optionally substituted, an aryl group which may be substituted with a halogen atom or an alkyl group, and a nitrogen atom-containing heterocyclic group which may have a substituent. Among these, it is preferable that R ¹³ to R ¹⁶ are 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.
One type of difluorophosphate may be used alone, or two or more types may be used in combination in any combination and ratio.

The content of difluorophosphate in the entire nonaqueous electrolyte of the present embodiment is not particularly limited, but is usually 0.001% by mass or more, preferably 0.01% by mass or more, based on 100% by mass of the nonaqueous electrolyte. The content is 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, even more preferably 2% by mass or less, and most preferably 1% by mass or less. When two or more types of difluorophosphates are used in combination, the total amount of difluorophosphates may satisfy the above range.
If the content of difluorophosphate is within this range, swelling of the non-aqueous electrolyte battery due to charging and discharging can be suitably suppressed.

<<Fluorosulfonate>>
As for the counter cation of the fluorosulfonate, the same explanation as in the case of the difluorophosphate described above applies.
Specific examples of the fluorosulfonate include lithium fluorosulfonate, sodium fluorosulfonate, potassium fluorosulfonate, rubidium fluorosulfonate, cesium fluorosulfonate, and the like, with lithium fluorosulfonate being preferred.

The fluorosulfonate salts may be used alone or in combination of two or more in any combination and ratio. Further, the content of the fluorosulfonate in the entire non-aqueous electrolyte of the present embodiment is not particularly limited, but is usually 0.001% by mass or more, preferably 0.01% by mass or more in 100% by mass of the non-aqueous electrolyte. , 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, still more preferably 2% by mass or less, and most preferably 1% by mass or less. be. When two or more types of fluorosulfonates are used in combination, the total amount of the fluorosulfonates may satisfy the above range.
If the content of the fluorosulfonate is within this range, swelling of the non-aqueous electrolyte battery due to charging and discharging can be suitably suppressed.

<<Salt having bisfluorosulfonylimide structure>>
As for the counter cation of the salt having a bisfluorosulfonylimide structure, the same explanation as in the case of the difluorophosphate described above applies.
Examples of the salt having a bisfluorosulfonylimide structure include lithium bisfluorosulfonylimide, sodium bisfluorosulfonylimide, potassium bisfluorosulfonylimide, and the like, with lithium bisfluorosulfonylimide being preferred.

The content of the salt having a bisfluorosulfonylimide structure in the entire nonaqueous electrolyte of the present embodiment is usually 0.001% by mass or more, preferably 0.01% by mass or more, based on 100% by mass of the nonaqueous electrolyte. The content is preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, and more preferably 3% by mass or less. When using two or more types of salts having a bisfluorosulfonylimide structure, the total amount of the salts having a bisfluorosulfonylimide structure may satisfy the above range.
If the content of the salt having a bisfluorosulfonylimide structure is within this range, swelling of the non-aqueous electrolyte battery due to charging and discharging can be suitably suppressed.

<1-2-7. Oxalate salt>
As for the counter cation of the oxalate salt, the same explanation as in the case of the difluorophosphate salt applies.
Specific examples of the oxalate salts in Group W include lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, lithium tris(oxalato)phosphate, and the like. are mentioned,
Lithium bis(oxalato)borate and lithium difluorobis(oxalato)phosphate are preferred.

One type of oxalate salt may be used alone, or two or more types may be used in combination in any combination and ratio. Further, the content of the oxalate salt in the entire nonaqueous electrolyte of the present embodiment is usually 0.001% by mass or more, preferably 0.01% by mass or more, and more preferably 0.01% by mass or more, based on 100% by mass of the nonaqueous electrolyte. The content is 1% by weight or more, and usually less than 8% by weight, preferably 5% by weight or less, more preferably 3% by weight or less, even more preferably 2% by weight or less, and most preferably 1.5% by weight or less. When using two or more oxalate salts in combination, the total amount of the oxalate salts may satisfy the above range.
If the content of oxalate salt is within this range, the non-aqueous electrolyte battery will easily exhibit sufficient cycle characteristic improvement effects, and the high-temperature storage characteristics will decrease, the amount of gas generated will increase, and the discharge capacity retention rate will decrease. This makes it easy to avoid situations where the

<1-3. Electrolyte>
The non-aqueous electrolytic solution of this embodiment usually contains an electrolyte as a component, like a general non-aqueous electrolytic solution. There are no particular limitations on the electrolyte used in the non-aqueous electrolyte of this embodiment, and any known electrolyte can be used. Specific examples of electrolytes will be described in detail below.

<Lithium salt>
As the electrolyte in the non-aqueous electrolyte of this embodiment, a lithium salt is usually used. As the lithium salt, there is no particular restriction as long as it is known to be used for this purpose, and any salt can be used, and specific examples include the following.

For example, inorganic lithium salts such as LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiTaF ₆ , LiWF ₇ ;
Lithium fluorophosphate salts such as LiPF ₆ ;
Lithium tungstate salts such as LiWOF ₅ ;
_{HCO2Li , CH3CO2Li , CH2FCO2Li , CHF2CO2Li , CF3CO2Li , CF3CH2CO2Li , CF3CF2CO2Li , CF3CF2CF2 _ _ _} Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
Sulfonic acid lithium salts such as CH ₃ SO ₃ Li;
LiN( _FCO2 ) ₂ , LiN(FCO)( _FSO2 ), LiN( _FSO2 ) ₂ , LiN( _FSO2 ) _{( CF3SO2 )} , LiN( _{CF3SO2 ) 2} , LiN( _C2F5 Lithium imides such as SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiN(CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) salts;
Lithium methide salts such as LiC( _{FSO2 ) 3} , LiC( _CF3SO2 ) ₃ , LiC _{( C2F5SO2 ) 3} ;
Lithium oxalate salts such as lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, lithium tris(oxalato)phosphate;
Others include _LiPF4 ( _CF3 ) ₂ , _{LiPF4 ( C2F5} ) ₂ , _{LiPF4 ( CF3SO2 ) 2} , _{LiPF4 ( C2F5SO2 ) 2} , _LiBF3CF3 , _{LiBF3C 2F5 , LiBF3C3F7} , _LiBF2 ( _{CF3 ) 2} , _LiBF2 ( _C2F5 ) _{2 , LiBF2} ( _{CF3SO2 ) 2 , LiBF2 ( C2F5SO2 ) 2} Fluorine-containing organolithium salts such as;
etc.

In addition to the effects of suppressing gas generation and suppressing battery resistance during high-temperature storage obtained in this embodiment, inorganic lithium salts, lithium fluorophosphate salts, and sulfonic acid Preferred are those selected from lithium salts, lithium imide salts, and lithium oxalate salts.
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, lithium difluorobis(oxalato)phosphate, lithium tris(oxalato)phosphate, etc. have low-temperature output characteristics and high rates. It is particularly preferred since it has the effect of improving charge/discharge characteristics, impedance characteristics, high temperature storage characteristics, cycle characteristics, and the like. Moreover, the above-mentioned electrolyte salts may be used alone or in combination of two or more kinds.

The total concentration of these electrolytes in the nonaqueous electrolyte is not particularly limited, but is usually 8% by mass or more, preferably 8.5% by mass or more, and more preferably 9% by mass based on the total amount of the nonaqueous electrolyte. % or more. Moreover, the upper limit is usually 18% by mass or less, preferably 17% by mass or less, and more preferably 16% by mass or less. When the total concentration of the electrolyte is within the above range, the electrical conductivity becomes appropriate for battery operation, and therefore sufficient output characteristics tend to be obtained.
In the non-aqueous electrolytic solution of the present embodiment, the mass ratio of the content of the compound represented by the general formula (A) to the content of lithium ions is not particularly limited as long as it does not significantly impair the effects of the present invention. It is preferably .0001 or more, more preferably 0.001 or more, and particularly preferably 0.01 or more. Further, the upper limit value is preferably 0.5 or less, more preferably 0.2 or less, and particularly preferably 0.1 or less. When the mass ratio of the above-mentioned compounds is within the above-mentioned preferable range, an insulating film is uniformly formed on the electrode surface by the compound represented by the general formula (A), which improves the resistance of the battery and during high-temperature storage. This is preferable in that the gas generation amount is well balanced.

<1-4. Non-aqueous solvent>
The non-aqueous electrolytic solution of this embodiment, like a general non-aqueous electrolytic solution, usually contains as its main component a non-aqueous solvent that dissolves the above-mentioned electrolyte. There are no particular limitations on the nonaqueous solvent used here, and any known organic solvent can be used. Examples of the organic solvent include saturated cyclic carbonates, chain carbonates, ether compounds, sulfone compounds, etc., but are not particularly limited thereto. These can be used alone or in combination of two or more.

<1-4-1. Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms, and saturated cyclic carbonates having 2 to 3 carbon atoms are preferably used from the viewpoint of improving battery characteristics due to improved degree of lithium ion dissociation. .
Examples of the saturated cyclic carbonate include ethylene carbonate, propylene carbonate, butylene carbonate, and the like. Among these, ethylene carbonate and propylene carbonate are preferred, and ethylene carbonate, which is less likely to be oxidized and reduced, is more preferred. One type of saturated cyclic carbonate 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 it does not significantly impair the effects of the present invention, but when one type is used alone, the lower limit of the content is based on the total amount of solvent in the non-aqueous electrolyte. The amount is usually 3% by volume or more, preferably 5% by volume or more. The total content of saturated cyclic carbonates is also not particularly limited, but is usually 3% by volume or more, preferably 5% by volume or more, based on the total amount of the solvent in the nonaqueous electrolyte. By setting this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the nonaqueous electrolyte can be avoided, and the large current discharge characteristics, stability with respect to the negative electrode, and cycle characteristics of the nonaqueous electrolyte battery can be maintained within a good range. It becomes easier to Further, the total content of saturated cyclic carbonates is 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 tends to improve, and the stability during high-temperature storage tends to improve.
Incidentally, the volume % in this specification means the volume at 25° C. and 1 atmosphere.

<1-4-2. 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 to an appropriate range, a chain carbonate having 3 to 5 carbon atoms is preferably used.
Specifically, the chain carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, Examples include isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butylethyl carbonate, isobutylethyl carbonate, t-butylethyl carbonate, and the like.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethylmethyl carbonate, and methyl-n-propyl carbonate are preferred, and dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate are particularly preferred. be.
Furthermore, chain carbonates having a fluorine atom (hereinafter sometimes abbreviated as "fluorinated chain carbonates") can also be suitably used. The number of fluorine atoms that the fluorinated chain carbonate has is not particularly limited as long as it is 1 or more, but it is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has multiple 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 ethylmethyl carbonate derivatives, and fluorinated diethyl carbonate derivatives.

Examples of fluorinated dimethyl carbonate derivatives include fluoromethylmethyl carbonate, difluoromethylmethyl carbonate, trifluoromethylmethyl carbonate, bis(fluoromethyl) carbonate, bis(difluoro)methyl carbonate, bis(trifluoromethyl) carbonate, and the like.
Examples of fluorinated ethylmethyl carbonate derivatives include 2-fluoroethylmethyl carbonate, ethylfluoromethyl carbonate, 2,2-difluoroethylmethyl carbonate, 2-fluoroethylfluoromethyl carbonate, ethyldifluoromethyl carbonate, and 2,2,2-trifluoromethyl carbonate. Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, ethyl trifluoromethyl carbonate, and the like.

Examples of fluorinated diethyl carbonate derivatives include ethyl-(2-fluoroethyl) carbonate, ethyl-(2,2-difluoroethyl) carbonate, bis(2-fluoroethyl) carbonate, and ethyl-(2,2,2-trifluoroethyl) carbonate. ethyl) carbonate, 2,2-difluoroethyl-2'-fluoroethyl carbonate, bis(2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2'-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2',2'-difluoroethyl carbonate and bis(2,2,2-trifluoroethyl) carbonate.

One type of chain carbonate may be used alone, or two or more types may be used in combination in any combination and ratio.
The content of chain carbonate is not particularly limited, but is usually 15% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, based on the total amount of the solvent in the nonaqueous electrolyte. Moreover, it is usually 90 volume% or less, preferably 85 volume% or less, and more preferably 80 volume% or less. By setting the content of chain carbonate within the above range, it is possible to maintain the viscosity of the non-aqueous electrolyte in an appropriate range, suppress a decrease in ionic conductivity, and, in turn, make it easier to maintain the output characteristics of the non-aqueous electrolyte battery within a favorable range. Become. When using two or more types of chain carbonates in combination, the total amount of chain carbonates may satisfy the above range.

Furthermore, by combining ethylene carbonate in a specific content with a specific linear carbonate, battery performance can be significantly improved.
For example, when dimethyl carbonate and ethyl methyl carbonate are selected as specific chain carbonates, the content of ethylene carbonate is not particularly limited and can be set arbitrarily as long as it does not significantly impair the effects of the present invention. The content of dimethyl carbonate is usually 15% by volume or more, preferably 20% by volume, and usually 45% by volume or less, preferably 40% by volume or less, based on the total amount of the solvent, and the content of dimethyl carbonate is based on the total amount of the solvent in the non-aqueous electrolyte. The content of ethyl methyl carbonate is usually 20 volume% or more, preferably 30 volume% or more, and usually 50 volume% or less, preferably 45 volume% or less, and the content of ethyl methyl carbonate is usually 20 volume% or more, preferably 30 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.

<1-4-3. Ether compounds>
As the ether compound, chain ethers having 3 to 10 carbon atoms and cyclic ethers having 3 to 6 carbon atoms are preferred.
Examples of chain ethers 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 ether. (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)ether, (3-fluoro-n-propyl)(2,2,3,3-tetrafluoro-n-propyl)ether, 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-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, ethoxymethoxymethane, 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-trifluoroethoxy)methane, ethoxy(1,1,2,2-tetrafluoroethoxy)methane, di(2-fluoroethoxy)methane, (2-fluoroethoxy)(2,2,2-trifluoro ethoxy)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-fluoroethoxy)ethane, ,2,2-trifluoroethoxy)ethane, methoxy(1,1,2,2-tetrafluoroethoxy)ethane, diethoxyethane, ethoxy(2-fluoroethoxy)ethane, ethoxy(2,2,2-trifluoroethoxy)ethane ethoxy)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, 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 include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane, etc., 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 a high ability to solvate lithium ions and have a high ionic dissociation property. This is preferable in that it improves performance. Particularly preferred are dimethoxymethane, diethoxymethane, and ethoxymethoxymethane because they have low viscosity and provide high ionic conductivity.

The ether compounds may be used alone or in combination of two or more in any desired ratio.
The content of the ether compound is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually at least 1% by volume, preferably at least 2% by volume, more preferably at least 2% by volume based on 100% by volume of the nonaqueous 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 two or more types of ether compounds are used in combination, the total amount of the ether compounds may satisfy the above range. If the content of the ether compound is within the above-mentioned preferred range, it is easy to ensure the effect of improving the ionic conductivity resulting from the improvement in the degree of lithium ion dissociation and the decrease in the viscosity of the chain ether. Furthermore, when the negative electrode active material is a carbonaceous material, the phenomenon in which chain ether is co-inserted with lithium ions can be suppressed, so that input/output characteristics and charge/discharge rate characteristics can be kept within appropriate ranges.

<1-4-4. Sulfone compounds>
The sulfone compound is not particularly limited, even if it is a cyclic sulfone or a chain sulfone, but in the case of a cyclic sulfone, the number of carbon atoms is usually 3 to 6, preferably 3 to 5, and in the case of a chain sulfone. , compounds having usually 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms are preferred. Further, 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 monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones; disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. Among them, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

As the sulfolanes, sulfolanes and/or sulfolane derivatives (hereinafter, sulfolanes may also be abbreviated as "sulfolanes") are preferred. As the sulfolane derivative, one in which one or more of the hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring is substituted with a fluorine atom or an alkyl group is preferable.
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-methyl Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methylsulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3-(trifluoromethyl)sulfolane, 3-fluoro-3-(trifluoromethyl)sulfolane, 4-fluoro-3-( Trifluoromethyl)sulfolane, 5-fluoro-3-(trifluoromethyl)sulfolane, and the like are preferred because they have high ionic conductivity and high input/output.

In addition, as chain sulfones, dimethylsulfone, ethylmethylsulfone, diethylsulfone, n-propylmethylsulfone, n-propylethylsulfone, di-n-propylsulfone, isopropylmethylsulfone, isopropylethylsulfone, diisopropylsulfone, n- Butylmethylsulfone, n-butylethylsulfone, t-butylmethylsulfone, t-butylethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, monofluoroethylmethylsulfone, difluoroethylmethylsulfone, Trifluoroethylmethylsulfone, pentafluoroethylmethylsulfone, ethyl monofluoromethylsulfone, ethyldifluoromethylsulfone, ethyltrifluoromethylsulfone, perfluoroethylmethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, di(trifluoroethylsulfone) fluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propylsulfone, difluoromethyl-n-propylsulfone, trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone , trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, pentafluoroethylisopropylsulfone, trifluoroethyl-n-butylsulfone, trifluoroethyl-t-butylsulfone, Examples include fluoromethyl-n-butylsulfone, trifluoromethyl-t-butylsulfone, pentafluoroethyl-n-butylsulfone, and pentafluoroethyl-t-butylsulfone.

Among them, dimethylsulfone, ethylmethylsulfone, diethylsulfone, n-propylmethylsulfone, isopropylmethylsulfone, n-butylmethylsulfone, t-butylmethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone. , 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 Ethylsulfone, trifluoromethyl-n-propylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-butylsulfone, trifluoroethyl-t-butylsulfone, trifluoromethyl-n-butylsulfone, trifluoromethyl-t - Butyl sulfone and the like are preferable because they improve the high-temperature storage stability of the electrolyte.

One type of sulfone compound may be used alone, or two or more types may be used in combination in any combination and ratio.
The content of the sulfone compound is not particularly limited and may be arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.3% by volume or more, preferably 0.3% by volume or more, based on the total amount of the solvent in the non-aqueous electrolyte. The content is 5% by volume or more, more preferably 1% by volume or more, and usually 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less. When two or more sulfone compounds are used in combination, the total amount of the sulfone compounds may satisfy the above range. If the content of the sulfone compound is within the above range, an electrolytic solution with excellent high-temperature storage stability tends to be obtained.

<1-5. Auxiliary agent>
The non-aqueous electrolytic solution of this embodiment may contain the following auxiliary agents within a range that achieves the effects of the present invention.
Carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, 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- Triple bond-containing compounds such as 2-(diethoxyphosphoryl) acetate, 1-methyl-2-propynyl-2-(diethoxyphosphoryl) acetate, 1,1-dimethyl-2-propynyl-2-(diethoxyphosphoryl) acetate ;

Spiro compounds such as 2,4,8,10-tetraoxaspiro[5.5]undecane and 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane;
Ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolene, ethylene sulfate, vinylene sulfate, diphenylsulfone, N,N-dimethylmethanesulfonamide, N,N- Sulfur-containing compounds such as diethylmethanesulfonamide, trimethylsilyl methylsulfate, trimethylsilyl ethylsulfate, 2-propynyl-trimethylsilylsulfate;
2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl crotonate, 2-(2-isocyanatoethoxy)ethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, 2-(2 - Isocyanate compounds such as isocyanatoethoxy)ethyl crotonate;
Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide;

Hydrocarbon compounds such as heptane, octane, nonane, decane, cycloheptane;
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, Fluorine-containing aromatic compounds such as 3,5-tris(trifluoromethyl)benzene, pentafluorophenyl methanesulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl acetate, pentafluorophenyl trifluoroacetate, methylpentafluorophenyl carbonate;

Tris borate (trimethylsilyl), tris borate (trimethoxysilyl), tris phosphate (trimethylsilyl), tris phosphate (trimethoxysilyl), dimethoxyaluminoxytrimethoxysilane, diethoxyaluminoxytriethoxysilane, dipropoxyalumino Oxytriethoxysilane, dibutoxyaluminoxytrimethoxysilane, dibutoxyaluminoxytriethoxysilane, titanium tetrakis (trimethyl siloxide), titanium tetrakis (triethyl siloxide),
Silane compounds such as;

2-Propynyl 2-(methanesulfonyloxy)propionate, 2-methyl 2-(methanesulfonyloxy)propionate, 2-ethyl 2-(methanesulfonyloxy)propionate, 2-propynyl methanesulfonyloxyacetate, methanesulfonyloxy Ester compounds such as 2-methyl acetate and 2-ethyl methanesulfonyloxyacetate;
Lithium ethylmethyloxycarbonylphosphonate, lithium ethyl ethyloxycarbonylphosphonate, lithium ethyl-2-propynyloxycarbonylphosphonate, lithium ethyl-1-methyl-2-propynyloxycarbonylphosphonate, lithium ethyl-1,1-dimethyl-2-propynyl Lithium salts such as oxycarbonylphosphonate;
etc. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity retention characteristics and cycle characteristics after high-temperature storage can be improved.

The content of other auxiliary agents is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the present invention. 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, and It is usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less. If the content of the auxiliary agent is within this range, the effects of the other auxiliary agents can be sufficiently expressed, and the high temperature storage stability tends to be improved. When two or more types of other auxiliaries are used in combination, the total amount of the other auxiliaries may satisfy the above range.

<2. Non-aqueous electrolyte battery>
A non-aqueous electrolyte battery according to an embodiment of the present invention includes a positive electrode having a current collector and a positive electrode active material layer provided on the current collector; The device includes a negative electrode having a negative electrode active material layer and capable of occluding and releasing metal ions, and the above-described non-aqueous electrolyte according to an embodiment of the present invention.

<2-1. Battery configuration>
The non-aqueous electrolyte battery of this embodiment is the same as a conventionally known non-aqueous electrolyte battery except for the non-aqueous electrolyte according to the embodiment of the present invention described above. Usually, a positive electrode and a negative electrode are laminated with a porous membrane (separator) impregnated with the above-mentioned non-aqueous electrolytic solution interposed therebetween, and these are housed in a case (exterior body). Therefore, the shape of the non-aqueous electrolyte battery of the present embodiment is not particularly limited, and may be any one of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

<2-2. Non-aqueous electrolyte>
As the non-aqueous electrolyte, the above-described non-aqueous electrolyte according to one embodiment of the present invention is used. Note that it is also possible to mix and use other non-aqueous electrolytes with the non-aqueous electrolyte according to one embodiment of the present invention without departing from the spirit of the present embodiment.

<2-3. Negative electrode＞
The negative electrode active material used in the negative electrode will be described below. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release metal ions. Specific examples include carbonaceous materials having carbon as a constituent element, alloy materials, and the like. These may be used alone or in any combination of two or more.

<2-3-1. Negative electrode active material>
As described above, examples of the negative electrode active material include carbonaceous materials, alloy materials, and the like.
Examples of the carbonaceous material include (1) natural graphite, (2) artificial graphite, (3) amorphous carbon, (4) carbon-coated graphite, (5) graphite-coated graphite, (6) resin-coated graphite, etc. It will be done.

(1) Examples of natural graphite include scaly graphite, flaky graphite, soil graphite, and/or graphite particles obtained by subjecting these graphites as raw materials to processes such as spheroidization and densification. Among these, from the viewpoint of particle filling properties and charge/discharge rate characteristics, spherical or ellipsoidal graphite that has been subjected to spheroidization treatment is particularly preferred.
As the device used for the spheroidization process, for example, a device that repeatedly applies mechanical effects such as compression, friction, and shear force, mainly impact force but also particle interaction, to the particles can be used.

Specifically, the casing has a rotor with many blades installed inside it, and as the rotor rotates at high speed, it applies impact compression, friction, and shear forces to the raw material of natural graphite (1) introduced inside. It is preferable to use an apparatus that applies a mechanical action such as the above to perform a spheronization process. Moreover, an apparatus having a mechanism for repeatedly applying mechanical action by circulating the raw material is preferable.

For example, when performing spheronizing treatment using the above-mentioned apparatus, the circumferential speed of the rotating rotor is preferably set to 30 to 100 m/sec, more preferably 40 to 100 m/sec, and 50 to 100 m/sec. More preferably, it is set to seconds. Although the spheroidization process can be carried out by simply passing the raw material through, it is preferable to circulate or retain the material in the apparatus for 30 seconds or more, and it is preferable to perform the process by circulating or retaining the raw material in the apparatus for 1 minute or more. is more preferable.

(2) Artificial graphite includes coal tar pitch, coal-based heavy oil, atmospheric residual oil, petroleum-based heavy oil, aromatic hydrocarbons, nitrogen-containing cyclic compounds, sulfur-containing cyclic compounds, polyphenylene, polyvinyl chloride, Organic compounds such as polyvinyl alcohol, polyacrylonitrile, polyvinyl butyral, natural polymers, polyphenylene sulfide, polyphenylene oxide, furfuryl alcohol resin, phenol-formaldehyde resin, imide resin, etc. are heated at a temperature usually above 2500°C and usually below 3200°C. Examples include those manufactured by graphitizing at high temperature and pulverizing and/or classifying as necessary.

At this time, a silicon-containing compound, a boron-containing compound, or the like can also be used as a graphitization catalyst. Another example is artificial graphite obtained by graphitizing mesocarbon microbeads separated during the heat treatment process of pitch. Furthermore, artificial graphite in the form of granulated particles consisting of primary particles may also be mentioned. For example, a graphitizable carbonaceous material powder such as mesocarbon microbeads or coke, a graphitizable binder such as tar or pitch, and a graphitization catalyst are mixed, graphitized, and crushed as necessary. Examples include graphite particles obtained by aggregating or bonding a plurality of flat particles such that their orientation planes are non-parallel.

(3) Amorphous carbon is amorphous carbon that has been heat-treated at least once in a temperature range that does not cause graphitization (range 400 to 2200°C) using a graphitizable carbon precursor such as tar or pitch as a raw material. Examples include particles and amorphous carbon particles heat-treated using a non-graphitizable carbon precursor such as a resin as a raw material.

(4) Examples of carbon-coated graphite include those obtained as follows. Natural graphite and/or artificial graphite and a carbon precursor, which is an organic compound such as tar, pitch, or resin, are mixed and heat-treated at least once in the range of 400 to 2300°C. The obtained natural graphite and/or artificial graphite is used as nuclear graphite, and this is coated with amorphous carbon to obtain a carbon graphite composite. This carbon-graphite composite is listed as carbon-coated graphite (4).

Further, the composite form may be a form in which the entire or part of the surface of nuclear graphite is coated with amorphous carbon, or a form in which a plurality of primary particles are combined with carbon originating from the carbon precursor as a binder. It's okay. Alternatively, natural graphite and/or artificial graphite can be reacted with hydrocarbon gas such as benzene, toluene, methane, propane, aromatic volatiles, etc. at high temperature to deposit carbon on the graphite surface (CVD). The carbon graphite composite can be obtained.

(5) Examples of graphite-coated graphite include those obtained as follows. Natural graphite and/or artificial graphite and a carbon precursor of an easily graphitizable organic compound such as tar, pitch, or resin are mixed and heat-treated at least once in the range of about 2400 to 3200°C. The obtained natural graphite and/or artificial graphite is used as core graphite, and the entire or part of the surface of the core graphite is coated with a graphitized substance to obtain graphite-coated graphite (5).

(6) Resin-coated graphite is, for example, natural graphite and/or artificial graphite obtained by mixing natural graphite and/or artificial graphite with resin, etc., and drying at a temperature of less than 400°C as core graphite, and resin etc. It can be obtained by coating the nuclear graphite with
Furthermore, the carbonaceous materials (1) to (6) described above may be used alone or in combination of two or more in any combination and ratio.

Organic compounds such as tar, pitch, and resin used in the carbonaceous materials (2) to (5) above include coal-based heavy oil, DC-based heavy oil, cracked petroleum heavy oil, and aromatic hydrocarbons. , N-ring compounds, S-ring compounds, polyphenylene, organic synthetic polymers, natural polymers, thermoplastic resins, and thermosetting resins. Further, the raw material organic compound may be used after being dissolved in a low-molecular organic solvent in order to adjust the viscosity during mixing.

Furthermore, as the natural graphite and/or artificial graphite that is a raw material for nuclear graphite, natural graphite subjected to spheroidization treatment is preferable.
Next, the above-mentioned alloy-based materials used as negative electrode active materials may be lithium alone, single metals and alloys forming lithium alloys, or their oxides, carbides, nitrides, silicones, etc., as long as they can absorb and release lithium. It may be any compound such as a compound, a sulfide or a phosphide, and is not particularly limited. The elemental metals and alloys forming the lithium alloy are preferably materials containing metals and metalloid elements of groups 13 and 14 (i.e. excluding carbon),
More preferred are elemental metals of aluminum, silicon and tin, and alloys or compounds containing these atoms,
More preferably, silicon or tin is used as a constituent element, such as elemental metals of silicon and tin, and alloys or compounds containing these atoms.
One type of these may be used alone, or two or more types may be used in combination in any combination and ratio.

<Metal particles that can be alloyed with Li>
When using single metals and alloys forming lithium alloys, or compounds such as their oxides, carbides, nitrides, silicides, sulfides, or phosphides as negative electrode active materials, the metals that can be alloyed with Li are: It is in particle form. Methods for confirming that metal particles are metal particles that can be alloyed with Li include identification of the metal particle phase using X-ray diffraction, observation and elemental analysis of particle structure using an electron microscope, and elemental analysis using fluorescent X-rays. Examples include analysis.

Any conventionally known metal particles that can be alloyed with Li can be used, but from the viewpoint of the capacity and cycle life of the non-aqueous electrolyte battery, the metal particles include, for example, Fe, Co, and Sb. , Bi, Pb, Ni, Ag, Si, Sn, Al, Zr, Cr, P, S, V, Mn, As, Nb, Mo, Cu, Zn, Ge, In, Ti, and W. Preferably, it is a metal or a compound thereof. Moreover, an alloy consisting of two or more types of metals may be used, and the metal particles may be alloy particles formed of two or more types of metal elements. Among these, metals selected from the group consisting of Si, Sn, As, Sb, Al, Zn and W or metal compounds thereof are preferred.

Examples of the metal compound include metal oxides, metal nitrides, metal carbides, and the like. Furthermore, an alloy consisting of two or more metals may be used.
Among metal particles that can be alloyed with Li, Si or a Si metal compound is preferred. The Si metal compound is preferably a Si metal oxide. Si or a Si metal compound is preferable from the viewpoint of increasing the capacity of the battery. In this specification, Si or Si metal compounds are collectively referred to as Si compounds. Specific examples of the Si compound include SiO _x , SiN _x , SiC _x , SiZ _x O _y (Z=C, N), and the like. The Si compound is preferably a Si metal oxide, and the Si metal oxide is represented by the general formula SiO _x . This general formula SiO _x is obtained using Si dioxide (SiO ₂ ) and metal Si (Si) as raw materials, and the value of x is usually 0≦x<2. SiO _x has a larger theoretical capacity than graphite, and amorphous Si or nano-sized Si crystals allow alkali ions such as lithium ions to enter and exit easily, making it possible to obtain a high capacity.

The Si metal oxide is specifically expressed as SiO _x , where x is 0≦x<2, more preferably 0.2 or more and 1.8 or less, and even more preferably 0. It is 4 or more and 1.6 or less, particularly preferably 0.6 or more and 1.4 or less. If _x of SiO x is within this range, the battery will have a high capacity and at the same time it will be possible to reduce the irreversible capacity due to the bond between Li and oxygen.

・Amount of oxygen contained in metal particles that can be alloyed with Li The amount of oxygen contained in metal particles that can be alloyed with Li is not particularly limited, but is usually 0.01 to 8% by mass, and 0.05 to 5% by mass. % is preferable. The oxygen distribution within the particles may be present near the surface, within the particles, or uniformly within the particles, but oxygen is preferably present near the surface. When the amount of oxygen contained in the metal particles that can be alloyed with Li is within the above range, the strong bond between the metal particles and O suppresses volumetric expansion accompanying secondary charging and discharging of the non-aqueous electrolyte, resulting in excellent cycle characteristics. preferable.

<Negative electrode active material containing metal particles and graphite particles that can be alloyed with Li>
The negative electrode active material may contain metal particles and graphite particles that can be alloyed with Li. The negative electrode active material may be a mixture in which metal particles that can be alloyed with Li and graphite particles are mixed in the state of independent particles, or metal particles that can be alloyed with Li are mixed on the surface of graphite particles. /or it may be a complex existing internally.

The above-mentioned composite of metal particles and graphite particles that can be alloyed with Li (also referred to as composite particles) is not particularly limited as long as it contains metal particles and graphite particles that can be alloyed with Li. However, particles in which metal particles and graphite particles that can be alloyed with Li are integrated through physical and/or chemical bonding are preferable. A more preferable form is a state in which the metal particles and graphite particles that can be alloyed with Li are dispersed within the particles to the extent that the metal particles and graphite particles are present at least both on the surface of the composite particle and inside the bulk. It is in such a form that graphite particles are present to unite them through physical and/or chemical bonding. A more specific preferred form is a composite material composed of at least metal particles that can be alloyed with Li and graphite particles, wherein the graphite particles, preferably natural graphite, have a curved surface and a folded structure. The composite material (negative electrode active material) is characterized in that metal particles capable of alloying with Li are present in the gaps within the structure. Further, the gap may be a void, or a substance such as amorphous carbon, graphite material, resin, etc. that buffers the expansion and contraction of metal particles that can be alloyed with Li is present in the gap. It's okay.

・Content ratio of metal particles that can be alloyed with Li The content ratio of metal particles that can be alloyed with Li based on the total of metal particles that can be alloyed with Li and graphite particles is usually 0.1% by mass or more, preferably 0. The content is .5% by mass or more, more preferably 1.0% by mass or more, even more preferably 2.0% by mass or more. Also, usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, especially Preferably it is 15% by mass or less, most preferably 10% by mass or less. This range is preferable because side reactions on the Si surface can be controlled and sufficient capacity can be obtained in a non-aqueous electrolyte battery.

(Coverage rate)
The negative electrode active material of this embodiment may be coated with a carbonaceous material or a graphite material. Among these, coating with an amorphous carbonaceous material is preferable from the viewpoint of acceptance of lithium ions. This coverage is usually 0.5% or more and 30% or less, preferably 1% or more and 25% or less, and more preferably 2% or more and 20% or less. The upper limit of the coverage rate is determined from the viewpoint of reversible capacity when the battery is assembled, and the lower limit of the coverage rate is determined from the viewpoint that the core carbonaceous material is uniformly coated with amorphous carbon and formed into strong granules. From the viewpoint of the particle size of the particles obtained when pulverized after firing, the above range is preferable.

The coverage (content) of carbides derived from organic compounds in the finally obtained negative electrode active material is determined by the amount of negative electrode active material, the amount of organic compounds, and the residual amount measured by the micro method in accordance with JIS K 2270. It can be calculated using the following formula depending on the charcoal ratio.
Formula: Coverage rate (%) of carbide derived from organic compound = (mass of organic compound × residual carbon rate × 100) / {mass of negative electrode active material + (mass of organic compound × residual carbon rate)}

(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. Further, it is usually less than 50%, preferably 40% or less, more preferably 30% or less, even more preferably 20% or less. If this internal porosity is too small, the amount of liquid within the particles of the negative electrode active material tends to decrease in a non-aqueous electrolyte battery. On the other hand, if the internal porosity is too large, the interparticle gaps tend to decrease when used as an electrode. It is preferable that the lower limit of the internal porosity is in the above range from the viewpoint of charge/discharge characteristics, and the upper limit is in the above range from the viewpoint of diffusion of the non-aqueous electrolyte. Further, as described above, this gap may be a void, or a material such as amorphous carbon, graphite material, resin, etc. that buffers the expansion and contraction of metal particles that can be alloyed with Li may be used in the gap. They may exist or gaps may be filled with these.

<2-3-2. Configuration and manufacturing method of negative electrode>
For producing the negative electrode, any known method can be used as long as the effects of the present invention are not significantly impaired. For example, it is formed by adding a binder, a solvent, and if necessary, a thickener, a conductive material, a filler, etc. to the negative electrode active material to form a slurry, applying this to a current collector, drying it, and then pressing it. can do.

Further, the alloy material negative electrode can be manufactured using any known method. Specifically, negative electrode manufacturing methods include, for example, adding a binder, a conductive material, etc. to the negative electrode active material described above and then roll-molding it as it is to make a sheet electrode, or compression molding it to make a pellet electrode. Although methods such as coating, vapor deposition, sputtering, plating, etc. on a negative electrode current collector (hereinafter sometimes referred to as "negative electrode current collector"), the above-mentioned negative electrode A method of forming a thin film layer (negative electrode active material layer) containing an active material is used. In this case, a binder, a thickener, a conductive material, a solvent, etc. are added to the above-mentioned negative electrode active material to form a slurry, and this is applied to the negative electrode current collector, dried, and then pressed to increase the density. , forming a negative electrode active material layer on the negative electrode current collector;

Examples of the material of the negative electrode current collector include steel, copper, copper alloy, nickel, nickel alloy, stainless steel, and the like. Among these, copper foil is preferred in terms of ease of processing into a thin film and cost.
The thickness of the negative electrode current collector is usually 1 μm or more, preferably 5 μm or more, and usually 100 μm or less, preferably 50 μm or less. If the negative electrode current collector is too thick, the capacity of the nonaqueous electrolyte battery as a whole may decrease too much, while if it is too thin, it may become difficult to handle.

Note that in order to improve the binding effect with the negative electrode active material layer formed on the surface, the surfaces of these negative electrode current collectors are preferably roughened in advance. Surface roughening methods include blasting, rolling with a rough roll, coated abrasive paper to which abrasive particles are fixed, a grindstone, an emery buff, a machine that polishes the current collector surface with a wire brush equipped with a steel wire, etc. Examples include mechanical polishing method, electrolytic polishing method, chemical polishing method, etc.

Furthermore, in order to reduce the mass of the negative electrode current collector and improve the energy density per mass of the battery, a perforated negative electrode current collector such as expanded metal or punched metal can also be used. The mass of this type of negative electrode current collector can be freely changed by changing its aperture ratio. Further, when negative electrode active material layers are formed on both sides of this type of negative electrode current collector, peeling of the negative electrode active material layer becomes more difficult to occur due to the rivet effect through the holes. However, if the aperture ratio becomes too high, the contact area between the negative electrode active material layer and the negative electrode current collector becomes small, so that the adhesive strength may decrease on the contrary.

A slurry for forming a negative electrode active material layer is usually prepared by adding a binder, a thickener, etc. to the negative electrode material. Note that the "negative electrode material" in this specification refers to a material that is a combination of a negative electrode active material and a conductive material.
The content of the negative electrode active material in the negative electrode material is usually 70% by mass or more, preferably 75% by mass or more, and usually 97% by mass or less, preferably 95% by mass or less. If 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 if it is too large, the content of the conductive material is relatively insufficient, resulting in a lack of electricity as a negative electrode. It tends to be difficult to ensure conductivity. Note that when two or more negative electrode active materials are used together, the total amount of the negative electrode active materials may satisfy the above range.

Examples of the conductive material used for the negative electrode include metal materials such as copper and nickel; carbon materials such as graphite and carbon black. One type of these may be used alone, or two or more types may be used in combination in any combination and 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, preferably 5% by mass or more, and usually 30% by mass or less, preferably 25% by mass or less. 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 etc. tends to be relatively insufficient, resulting in a tendency for the battery capacity and strength to decrease. In addition, when two or more electrically conductive materials are used together, the total amount of the electrically conductive materials may satisfy the above range.

As the binder used in the negative electrode, any material can be used as long as it is safe for the solvent and electrolyte used during electrode manufacture. Examples include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene/butadiene rubber/isoprene rubber, butadiene rubber, ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer, and the like. One type of these may be used alone, or two or more types may be used in combination in any combination and 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, preferably 8 parts by mass or less, based on 100 parts by mass of the negative electrode material. . If the binder content is too low, the resulting negative electrode tends to lack strength, and if it is too high, the battery capacity and conductivity tend to be insufficient due to a relative lack of negative electrode active material, etc. becomes. In addition, when using two or more binders together, the total amount of the binders may satisfy the above range.

Examples of the thickener used in the negative electrode include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein. One type of these may be used alone, or two or more types may be used in combination in any combination and ratio. A thickener may be used as necessary, but when used, the content of the thickener in the negative electrode active material layer should generally be in the range of 0.5% by mass or more and 5% by mass or less. is preferred.

The slurry for forming the negative electrode active material layer is prepared by mixing the above negative electrode active material with a conductive material, a binder, and a thickener as necessary, and using an aqueous solvent or an organic solvent as a dispersion medium. Ru. Water is usually used as the aqueous solvent, but alcohols such as ethanol and organic solvents such as cyclic amides such as N-methylpyrrolidone may be used in combination in an amount of 30% by mass or less based on water. You can also do it. In addition, organic solvents include cyclic amides such as N-methylpyrrolidone, linear amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and aromatic hydrocarbons such as anisole, toluene, and xylene. Among them, cyclic amides such as N-methylpyrrolidone, linear amides such as N,N-dimethylformamide, N,N-dimethylacetamide, etc. are preferred. In addition, any one type of these may be used alone, or two or more types may be used in combination in any combination and ratio.
The obtained slurry is applied onto the above-mentioned negative electrode current collector, dried, and then pressed to form a negative electrode active material layer and obtain a negative electrode. The coating method is not particularly limited, and any known method can be used. The drying method is not particularly limited either, and known methods such as natural drying, heat drying, reduced pressure drying, etc. can be used.

(electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g·cm ^-3 or more, and 1.2 g·cm ^-3 or more. is more preferably 1.3 g·cm ^-3 or more, particularly preferably 2.2 g·cm ^-3 or less, more preferably 2.1 g·cm ^-3 or less, and 2.0 g·cm ^-3 or less. More preferably, it is 1.9 g·cm ⁻³ or less. If the density of the negative electrode active material present on the current collector exceeds the above range, the negative electrode active material particles will be destroyed, resulting in an increase in the initial irreversible capacity of the non-aqueous electrolyte battery, or a decrease in the current collector/negative electrode active material. This may lead to deterioration of high current density charge/discharge characteristics due to decreased permeability of the non-aqueous electrolyte near the interface. Moreover, when it is less than the above range, the conductivity between negative electrode active materials may decrease, battery resistance may increase, and capacity per unit volume may decrease.

<2-4. Positive electrode>
The positive electrode used in the non-aqueous electrolyte battery of this embodiment will be described below.
<2-4-1. Cathode active material>
The positive electrode active material used in the positive electrode will be explained below.

(1) Composition The positive electrode active material is lithium cobalt oxide or a transition metal oxide containing at least Ni and Co, in which 50 mol% or more of the transition metals are Ni and Co. There is no particular restriction as long as it can intercalate and deintercalate lithium ions, but for example, it is preferable to use a material that can electrochemically intercalate and deintercalate lithium ions, containing lithium and at least Ni and Co, and containing 50 mol of transition metals. Transition metal oxides in which Ni and Co account for at least % are preferred. 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 metal components of the lithium transition metal oxide include Ni and Co as essential transition metal elements, and other metal elements such as Mn, V, Ti, Cr, Fe, Cu, Al, Mg, Zr, Er, etc. Mn, Ti, Fe, Al, Mg, Zr, etc. are preferred. Specific examples of lithium transition metal oxides 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 , LiNi _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 _0.1 O ₂ and the like.

Among these, a transition metal oxide represented by the following compositional formula (1) is preferable.
Li _a1 Ni _b1 Co _c1 M _d1 O ₂ ...(1)
(In formula (1), the numerical values are 0.90≦a1≦1.10, 0.50≦b1≦0.98, 0.01≦c1<0.50, 0.01≦d1<0.50. , b1+c1+d1=1.M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er.)
In the compositional formula (1), it is preferable that 0.1≦d1<0.5.

By keeping the composition ratios of Ni and Co and the composition ratios of other metals as specified, transition metals are difficult to elute from the positive electrode, and even if they do, Ni and Co will remain in the non-aqueous secondary battery. This is because the negative effects of
Among these, a transition metal oxide represented by the following compositional formula (2) is more preferable.
Li _a2 Ni _b2 Co _c2 M _d2 O ₂ ...(2)
(In formula (2), the numerical values are 0.90≦a2≦1.10, 0.50≦b2≦0.89, 0.10≦c2<0.50, 0.01≦d2<0.40. , b2+c2+d2=1.M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er.)
In compositional formula (2), it is preferable that the numerical value is 0.10≦d2<0.40.

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

This is because the above composition makes it possible to obtain particularly high capacity when used as a positive electrode for a non-aqueous secondary battery.
Furthermore, two or more of the above positive electrode active materials may be used in combination. Similarly, at least one of the above positive electrode active materials and other positive electrode active materials may be mixed and used. Examples of other positive electrode active materials include transition metal oxides, transition metal phosphate compounds, transition metal silicate compounds, and transition metal borate compounds not listed above.

Among these, lithium-manganese composite oxides having a spinel-type structure and lithium-containing transition metal phosphoric acid compounds having an olivine-type structure are preferred. Specifically, examples of the lithium manganese composite oxide having a spinel structure include LiMn ₂ O ₄ , LiMn _1.8 Al _0.2 O ₄ , LiMn _1.5 Ni _0.5 O ₄ and the like. This is because it has the most stable structure and is less likely to release oxygen even in the event of an abnormality in a non-aqueous electrolyte battery, offering excellent safety.

The transition metal of the lithium-containing transition metal phosphate compound is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. Specific examples include LiFePO ₄ , 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 , and some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are replaced with Al, Ti, Examples include those substituted with other metals such as V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W.

Among these, lithium iron phosphate compounds are preferred because iron is an extremely inexpensive metal with abundant resources and is less harmful. That is, among the above specific examples, LiFePO ₄ can be cited as a more preferable specific example.

(2) Surface coating It is also possible to use a cathode active material with a substance (hereinafter referred to as a "surface-attached substance" as appropriate) attached to the surface of the cathode active material having a composition different from that of the substance constituting the main cathode active material. . Examples of surface-attached substances include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, Examples 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 can be prepared, for example, by dissolving or suspending them in a solvent, impregnating them into the positive electrode active material, and then drying them, or by dissolving or suspending a surface-adhering substance precursor in a solvent and impregnating them into the positive electrode active material. It can be attached to the surface of the positive electrode active material by a method of reacting it by heating or the like after heating, or by a method of adding it to the positive electrode active material precursor and baking it at the same time. In addition, when attaching carbon, it is also possible to use a method of mechanically attaching carbonaceous matter in the form of activated carbon or the like afterwards.

The mass of the surface-attached substance adhering to the surface of the positive electrode active material is preferably 0.1 ppm or more, more preferably 1 ppm or more, and even more preferably 10 ppm or more, based on the mass of the positive electrode active material. Moreover, it is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less.
The surface-attached substance can suppress the oxidation reaction of the non-aqueous electrolyte on the surface of the positive electrode active material, and can improve battery life. Further, when the amount of adhesion is within the above range, the effect can be fully exhibited, and the resistance will not increase easily without inhibiting the ingress and egress of lithium ions.

(3) Shape The shape of the positive electrode active material particles may be a lump, a polyhedron, a sphere, an ellipsoid, a plate, a needle, a column, etc., which are conventionally used. Further, primary particles may aggregate to form secondary particles, and the shape of the secondary particles may be spherical or ellipsoidal.

(4) Method for manufacturing the positive electrode active material The method for manufacturing the positive electrode active material is not particularly limited as long as it does not go beyond the gist of this embodiment, but there are several methods that are commonly used as methods for manufacturing inorganic compounds. methods are used.
In particular, various methods can be considered to produce a spherical or ellipsoidal active material. For example, one method is to use a transition metal raw material such as a transition metal nitrate or sulfate, 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 collect a spherical precursor. After drying this as necessary, LiOH, Li ₂ CO ₃ , LiNO A method of obtaining an active material by adding a Li source such as _{No. 3} and firing at a high temperature can be mentioned.

In addition, as an example of another method, transition metal raw materials such as transition metal nitrates, sulfates, hydroxides, oxides, etc., and raw materials of other elements as necessary, are dissolved or pulverized and dispersed in a solvent such as water. A method of obtaining an active material by drying and molding it with a spray dryer or the like to obtain a spherical or ellipsoidal precursor, adding a Li source such as LiOH, Li ₂ CO ₃ , or LiNO ₃ to this and firing at a high temperature. can be mentioned.

As an example of yet another method, a transition metal raw material such as a transition metal nitrate, sulfate, hydroxide, or oxide, a Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ , and other elements as necessary The active material is obtained by dissolving or pulverizing and dispersing the raw material in a solvent such as water, drying and molding it with a spray dryer etc. to obtain a spherical or ellipsoidal precursor, and firing this at a high temperature to obtain the active material. Can be mentioned.

<2-4-2. Positive electrode structure and manufacturing method>
Below, the structure of the positive electrode used in this embodiment and its manufacturing method will be explained.
(Production method of positive electrode)
The positive electrode is produced by forming a positive electrode active material layer containing positive electrode active material particles and a binder on a current collector. A positive electrode using a positive electrode active material can be manufactured by any known method. For example, a positive electrode active material, a binder, and if necessary a conductive material, a thickener, etc. are mixed together in a dry process and formed into a sheet, which is then pressed onto a positive electrode current collector, or these materials are mixed in a liquid medium. A positive electrode can be obtained by dissolving or dispersing the slurry, applying it to a positive electrode current collector, and drying it to form a positive electrode active material layer on the current collector.

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, even more preferably 80% by mass or more, and preferably 99.9% by mass or less. Yes, and more preferably 99% by mass or less. When the content of the positive electrode active material is within the above range, sufficient electric capacity can be ensured. Furthermore, the strength of the positive electrode is also sufficient. Note that the positive electrode active material powder in this embodiment may be used alone, or two or more types having different compositions or different powder physical properties may be used in any combination and ratio. When using two or more types 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 few resources, and large batteries that require high capacity, such as those used in automobiles, require a large amount of active material, which is undesirable from a cost standpoint, so they are less expensive. This is because it is desirable to use manganese as a main component as a transition metal.

(conductive material)
As the conductive material, any known conductive material can be used. Specific examples 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 use 2 or more types together in 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, even more preferably 1% by mass or more, and preferably 50% by mass or less. The content is more preferably 30% by mass or less, and even more preferably 15% by mass or less. When the content is within the above range, sufficient electrical conductivity can be ensured. 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 that is stable to the non-aqueous electrolyte and the solvent used during electrode production.
In the case of the coating method, there are no particular limitations as long as the material is dissolved or dispersed in the liquid medium used during electrode production, but specific examples include polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, and cellulose. , resin-based polymers such as nitrocellulose; rubber-like polymers such as SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber; styrene-butadiene rubber; Styrene block copolymer or its hydrogenated product, EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-ethylene copolymer, styrene-isoprene-styrene block copolymer or its hydrogenated product Thermoplastic elastomeric polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene/vinyl acetate copolymers, propylene/α-olefin copolymers, etc.; polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene/ethylene copolymer, and other fluorine-based polymers; polymer compositions with ionic conductivity for alkali metal ions (particularly lithium ions), etc. can be mentioned. Note that these substances may be used alone or in combination of two or more in any desired 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, even more preferably 3% by mass or more, and preferably 80% by mass or less. The content is more preferably 60% by mass or less, even more preferably 40% by mass or less, and particularly preferably 10% by mass or less. When the ratio of the binder is within the above range, the positive electrode active material can be sufficiently retained and the mechanical strength of the positive electrode can be ensured, resulting in good battery performance such as cycle characteristics. Furthermore, it also helps avoid deterioration in battery capacity and conductivity.

(liquid medium)
The liquid medium used to prepare the slurry for forming the positive electrode active material layer is capable of dissolving or dispersing the positive electrode active material, the conductive material, the binder, and the thickener used as necessary. There is no particular restriction 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; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone. esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N,N-dimethylaminopropylamine; ethers such as diethyl ether and tetrahydrofuran (THF); N-methylpyrrolidone (NMP) and dimethylformamide , amides such as dimethylacetamide; aprotic polar solvents such as hexamethylphosphalamide and dimethylsulfoxide; and the like. In addition, these may be used individually by 1 type, or may use 2 or more types together in arbitrary combinations and ratios.

(thickener)
When an aqueous medium is used as a liquid medium for forming a slurry, it is preferable to use a thickener and a latex such as styrene-butadiene rubber (SBR) to form a slurry. 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, but specific examples include 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 combination of two or more in any combination and 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 even more preferably 0.6% by mass or more. Preferably, the content is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less. If it is within the above range, the coating properties will be good, and the ratio of the active material in the positive electrode active material layer will be sufficient, which will reduce the problem of battery capacity reduction and increase the resistance between the positive electrode active materials. It becomes easier to avoid problems.

(consolidation)
The positive electrode active material layer obtained by coating and drying the slurry on a current collector is preferably compacted by hand pressing, roller pressing, etc. 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, It is more preferably 3.5 g·cm ^-3 or less, particularly preferably 3 g·cm ^-3 or less.
When the density of the positive electrode active material layer is within the above range, the permeability of the non-aqueous electrolyte to the vicinity of the current collector/active material interface will not decrease, and the charging and discharging characteristics will be particularly good at high current densities. Become. Furthermore, the conductivity between active materials is less likely to decrease, and battery resistance is less likely to increase.

(current collector)
There are no particular limitations on the material of the positive electrode current collector, 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. Among these, metal materials, particularly aluminum, are preferred.

In the case of metal materials, 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 carbonaceous materials, examples include carbon plate, Examples include carbon thin films and carbon cylinders. Among these, metal thin films are preferred. Note that the thin film may be formed into a mesh shape as appropriate.
The thickness of the current collector is arbitrary, but is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and preferably 1 mm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. preferable. When the thickness of the current collector is within the above range, the strength required for the current collector can be sufficiently ensured. Furthermore, handling properties are also improved.

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

(electrode area)
From the viewpoint of increasing stability at high output and high temperature, it is preferable that the area of the positive electrode active material layer be larger than the outer surface area of the battery outer case. Specifically, the total area of the positive electrode relative to the surface area of the exterior of the non-aqueous electrolyte battery is preferably 20 times or more, more preferably 40 times or more, in terms of area ratio. In the case of a square shape with a bottom, the outer surface area of the outer case refers to the total area calculated from the length, width, and thickness of the case filled with the power generation element, excluding the protruding parts of the terminals. . In the case of a cylindrical shape with a bottom, the geometric surface area is approximated by assuming that the case portion filled with the power generation element excluding the protruding portion of the terminal is a cylinder. The total electrode area of the positive electrode is the geometric surface area of the positive electrode composite material layer facing the composite material layer containing the negative electrode active material. , refers to the sum of the areas calculated for each surface separately.

(discharge capacity)
When using the non-aqueous electrolyte according to an embodiment of the present invention, the electrical capacity of the battery element housed in one battery exterior of the non-aqueous electrolyte battery (when the battery is discharged from a fully charged state to a discharged state) It is preferable that the electric capacity (electric capacity) is 1 ampere hour (Ah) or more because the effect of improving low temperature discharge characteristics becomes large. Therefore, the discharge capacity of the positive electrode plate is preferably 3Ah (ampere hour) when fully charged, more preferably 4Ah or more, and preferably 100Ah or less, more preferably 70Ah or less, and particularly preferably 50Ah. Design as follows.

Within the above range, voltage drop due to electrode reaction resistance does not become too large when drawing a large current, and deterioration of power efficiency can be prevented. Furthermore, the temperature distribution due to heat generated inside the battery during pulse charging and discharging does not become too large, resulting in poor durability for repeated charging and discharging, and heat dissipation efficiency is poor in response to sudden heat generation during abnormalities such as overcharging and internal short circuits. It is possible to avoid this phenomenon.

(Thickness of positive electrode 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 after subtracting the thickness of the current collector should be The thickness is preferably 10 μm or more, more preferably 20 μm or more, and preferably 200 μm or less, and more preferably 100 μm or less.

<2-5. Separator>
A separator is usually interposed between the positive electrode and the negative electrode to prevent short circuits. In this case, the separator is usually impregnated with the non-aqueous electrolyte.
There are no particular restrictions on the material or shape of the separator, and any known material can be used as long as it does not significantly impair the effects of the present invention. Among them, resins, glass fibers, inorganic materials, etc. made of materials that are stable against the above-mentioned non-aqueous electrolytes are used, and porous sheets or non-woven fabrics with excellent liquid retention properties are used. preferable.

As materials for the resin and glass fiber separators, for example, polyolefins such as polyethylene and polypropylene, polytetrafluoroethylene, polyethersulfone, glass filters, etc. can be used. Among them, glass filters and polyolefins are preferred, and polyolefins are more preferred. One type of these materials may be used alone, or two or more types may be used in combination 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 insulation properties and mechanical strength may decrease. Moreover, if the thickness is too thick than the above range, not only battery performance such as rate characteristics may deteriorate, but also the energy density of the non-aqueous electrolyte battery as a whole may decrease.

Furthermore, when using a porous material such as a porous sheet or nonwoven fabric as a separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, if it is too large than the above range, the mechanical strength of the separator tends to decrease and the insulation properties tend to decrease.

Further, the average pore diameter of the separator is also arbitrary, but it is usually 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. When the average pore diameter exceeds the above range, short circuits tend to occur. Moreover, if it falls below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. things are used.

As for the form, those in the form of a thin film such as nonwoven fabric, woven fabric, and microporous film are used. In the case 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 independent thin film shape described above, a separator can be used in which a composite porous layer containing the inorganic particles is formed on the surface layer of the positive electrode and/or negative electrode using a resin binder. For example, a porous layer may be formed on both sides of the positive electrode using alumina particles having a 90% particle size of less than 1 μm and a fluororesin as a binder.

<2-6. Battery design>
[Electrode group]
The electrode group has a laminated structure in which the above-mentioned positive electrode plate and negative electrode plate are interposed with the above-mentioned separator in between, and an electrode group in which the above-mentioned positive electrode plate and negative electrode plate are spirally wound with the above-mentioned separator interposed in between. Either is fine. The ratio of the volume of the electrode group to the internal battery volume (hereinafter referred to as electrode group occupancy) is usually 40% or more, preferably 50% or more, and usually 90% or less, and 80% or less. preferable. The lower limit of the electrode group occupancy is preferably within the above range from the viewpoint of battery capacity. In addition, the upper limit of the electrode group occupancy rate is set in order to secure the gap space, from the viewpoint of various characteristics such as the repeated charging and discharging performance of the battery and high temperature storage, and from the viewpoint of avoiding activation of the gas release valve that releases internal pressure to the outside. It is preferable to set it as the said range. If the gap space is too small, the battery's high temperature will cause the components to expand and the vapor pressure of the liquid electrolyte to increase, increasing the internal pressure, which will affect the battery's charge/discharge cycle performance and high-temperature storage. This may reduce properties or even activate a gas release valve that releases internal pressure to the outside.

[Current collection structure]
Although the current collecting structure is not particularly limited, in order to more effectively suppress gas generation during high-temperature storage and suppress an increase in internal resistance of the battery using the non-aqueous electrolyte according to an embodiment of the present invention, It is preferable to adopt a structure that reduces the resistance of wiring portions and bonding portions. When the internal resistance is reduced in this way, the effects of using the above-mentioned non-aqueous electrolyte are particularly well exhibited.

When the electrode group has the above-mentioned laminated structure, a structure in which the metal core portions of each electrode layer are bundled and welded to a terminal is preferably used. When the area of one electrode becomes large, the internal resistance becomes large, so it is also suitable to provide a plurality of terminals within the electrode to reduce the resistance. When the electrode group has the above-mentioned wound structure, the internal resistance can be lowered by providing a plurality of lead structures on each of the positive and negative electrodes and bundling them into a terminal.

[Protective element]
As protective elements, PTC (Positive Temperature Coefficient), which increases resistance when abnormal heat generation or excessive current flows, thermal fuse, thermistor, interrupts current flowing through the circuit due to sudden rise in battery internal pressure or internal temperature when abnormal heat generation occurs. valves (current cutoff valves), etc. It is preferable that the protection element is selected so that it does not operate under normal use of high current, and from the viewpoint of high output, it is more preferable to use a design that does not lead to abnormal heat generation or thermal runaway even without the protection element.

[Exterior body]
The non-aqueous electrolyte battery of this embodiment is usually configured by housing the above-mentioned non-aqueous electrolyte, a negative electrode, a positive electrode, a separator, etc. in an exterior body (exterior case). There is no limit to this exterior body, and any known exterior body can be used as long as it does not significantly impair the effects of the present invention.
The material of the outer case is not particularly limited as long as it is stable to the non-aqueous electrolyte used. Specifically, metals such as nickel-plated steel sheets, stainless steel, aluminum or aluminum alloys, magnesium alloys, nickel, and titanium, or laminated films of resin and aluminum foil are preferably used.

For exterior cases using the above metals, the metals are welded together using laser welding, resistance welding, or ultrasonic welding to create a hermetically sealed structure, or the metals are caulked using a resin gasket. There are things that do. Examples of exterior cases using the above-mentioned laminate film include those in which resin layers are heat-sealed to each other to form a hermetically sealed structure. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when creating a sealed structure by heat-sealing a resin layer via a current collector terminal, the metal and resin are joined, so the intervening resin may be a resin with a polar group or a modified resin with a polar group introduced. Resin is preferably used.
Further, the shape of the exterior body is also arbitrary, and may be, for example, cylindrical, square, laminated, coin-shaped, large-sized, or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples; however, the present invention is not limited to these Examples unless the gist thereof is exceeded.
Compounds 1 to 3 used in the Examples and Comparative Examples are shown below. Compound 1 corresponds to the compound represented by general formula (A) in the specification of the present invention.

<Examples 1-1 to 1-2, Comparative Examples 1-1 to 1-3>
[Preparation of positive electrode]
90 parts by mass of lithium-nickel-cobalt-manganese composite oxide (Li _1.0 Ni _0.5 Co _0.2 Mn _0.3 O ₂ ) as a positive electrode active material, 7 parts by mass of acetylene black as a conductive material, and a 3 parts by mass of polyvinylidene fluoride (PVdF) as an adhesive was mixed in an N-methylpyrrolidone solvent using a disperser to form a slurry. This was applied uniformly to both sides of an aluminum foil having a thickness of 15 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
98 parts by mass of natural graphite, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose 1% by mass) and an aqueous dispersion of styrene-butadiene rubber (styrene-butadiene rubber) as thickeners and binders. 1 part by mass (concentration 50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to one side of a copper foil having a thickness of 10 μm, dried, and then pressed to form a negative electrode.

[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, sufficiently dried LiPF was added as an electrolyte to a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) (volume ratio EC:DEC:EMC=3:6:1). ₆ was dissolved at 1.15 mol/L (14% by mass as the concentration in the non-aqueous electrolyte), and 1.15% by mass of monofluoroethylene carbonate (FEC) and 1.1% by mass of methylenemethane disulfonate (MMDS) were dissolved. 0% by mass (as a concentration in the non-aqueous electrolytic solution) was added (hereinafter, this will be referred to as reference electrolytic solution 1). A non-aqueous electrolyte solution was prepared by adding Compounds 1 to 3 as additives to the reference electrolyte solution 1 in the contents shown in Table 1 below. In addition, "content (mass %)" in the table is the content when the entire non-aqueous electrolyte is 100 mass %.

[Manufacture of non-aqueous electrolyte battery]
A battery element was produced by laminating the above positive electrode, negative electrode, and polyethylene separator in the order of negative electrode, separator, and positive electrode. After inserting this battery element into a bag made of a laminate film made of aluminum (40 μm thick) coated with resin layers on both sides so that the positive and negative terminals protrude, the non-aqueous electrolyte prepared above is poured into the bag. A laminated non-aqueous electrolyte battery was fabricated by injecting the solution into the battery and vacuum-sealing it.

<Evaluation of non-aqueous electrolyte batteries>
[Initial conditioning]
The non-aqueous electrolyte battery prepared by the above method was heated in a constant temperature bath at 25°C with a current equivalent to 0.1C (1C refers to the current value that takes 1 hour to charge or discharge. The same applies hereinafter). After constant current charging to 3.2V at 0.2C, constant current-constant voltage charging (hereinafter referred to as CC-CV charging) was performed to 4.2V at 0.2C. Thereafter, aging was carried out by holding at 45° C. for 120 hours. Thereafter, the battery was discharged to 2.5V at 0.2C to stabilize the non-aqueous electrolyte battery. Further, after performing CC-CV charging at 0.2C to 4.2V, initial conditioning was performed by discharging to 2.5V at 0.2C (the discharge capacity at this time is defined as the initial discharge capacity).

After initial conditioning, the battery was charged by CC-CV at 0.2C to half the initial discharge capacity. This was discharged at 1.0 C, 2.0 C, and 3.0 C at 25° C., and the voltage at 5 seconds was measured. The average value of the slopes of the current-voltage straight lines obtained at 1.0C, 2.0C, and 3.0C was taken as the initial internal resistance.

<Evaluation of non-aqueous electrolyte batteries>
[High temperature storage test]
After initial conditioning, the laminated non-aqueous electrolyte battery was again CC-CV charged at 0.2C to 4.2V, and then stored at high temperature at 60°C for 168 hours. After the non-aqueous electrolyte battery was sufficiently cooled, it was immersed in an ethanol bath and its volume was measured, and the amount of gas generated was determined from the change in volume before and after the storage test, and this was taken as the amount of high-temperature storage gas.

In addition, the cell after the storage test was discharged to 2.5V at 0.2C, CC-CV charged to half the initial discharge capacity at 0.2C, and the internal resistance of the battery was determined in the same manner as above. This was taken as the internal resistance after the storage test. The "internal resistance increase rate" was calculated from the following formula (4).
Internal resistance increase rate = [(internal resistance after storage test)/(initial internal resistance)] x 100% (4)
Table 1 below shows the ratio of the high temperature storage gas amount and the internal resistance increase rate when the high temperature storage gas amount and internal resistance increase rate of Comparative Example 1-1 are each set to 100.

All of Examples 1-1 to 1-2 containing Compound 1, which corresponds to the compound represented by general formula (A), were able to significantly reduce the amount of high-temperature storage gas compared to Comparative Example 1-1. At the same time, the rate of increase in internal resistance was also reduced.
On the other hand, in Comparative Examples 1-2 to 1-3 containing Compound 2, although the amount of high-temperature storage gas was reduced compared to Comparative Example 1-1, the improvement range was not as great as in Example 1-1. However, the internal resistance actually increased.

This application is based on a Japanese patent application (Japanese Patent Application No. 2018-232347) filed on December 12, 2018, the contents of which are incorporated herein by reference.

By using the non-aqueous electrolyte according to the present invention, the amount of gas generated during high-temperature storage of a non-aqueous electrolyte battery can be suppressed, and battery resistance can be reduced. Therefore, the nonaqueous electrolyte according to the present invention can be suitably used as a nonaqueous electrolyte for laminated batteries.
Further, the non-aqueous electrolyte according to the present invention and the non-aqueous electrolyte battery using the same can be used in various known applications using non-aqueous electrolyte batteries. Specific examples include notebook computers, pen input computers, mobile computers, e-book players, mobile phones, mobile fax machines, mobile copiers, mobile printers, headphone stereos, video movies, LCD televisions, handy cleaners, portable CDs, and mini discs. , transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, motorcycles, motorized bicycles, bicycles, lighting equipment, toys, game equipment, watches, power tools, strobes, cameras, home backups Examples include power sources, backup power sources for business offices, power sources for load leveling, natural energy storage power sources, and lithium ion capacitors.

Claims (10)

A non-aqueous electrolytic solution containing a compound represented by the following general formula (A).

(In formula (A), R ¹ to R ⁴ each independently represent a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and X may have a substituent. (Indicates an alkylene group having 1 to 12 carbon atoms.) The non-aqueous electrolytic solution according to claim 1, wherein at least one of R ¹ to R ⁴ in the general formula (A) is a hydrocarbon group having 1 to 12 carbon atoms and having a carbon-carbon unsaturated bond. The non-aqueous electrolyte according to claim 2, wherein the hydrocarbon group having 1 to 12 carbon atoms and having a carbon-carbon unsaturated bond is an allyl group or a methallyl group. According to any one of claims 1 to 3, the content of the compound represented by the general formula (A) is 0.001% by mass or more and 10% by mass or less based on the total amount of the nonaqueous electrolyte. Non-aqueous electrolyte as described. The nonaqueous electrolyte is a group consisting of a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a compound having a cyano group, a diisocyanate compound, a cyclic sulfonic acid ester, a fluorinated salt, and an oxalate salt. The non-aqueous electrolytic solution according to any one of claims 1 to 4, containing at least one compound selected from W. A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, the non-aqueous electrolyte being the non-aqueous electrolyte according to any one of claims 1 to 5. electrolyte battery. The non-aqueous electrolyte battery according to claim 6, wherein the negative electrode includes a negative electrode active material, and the negative electrode active material contains carbon. The non-aqueous electrolyte battery according to claim 6, wherein the negative electrode includes a negative electrode active material, and the negative electrode active material contains silicon (Si) or tin (Sn). The nonaqueous electrolyte according to claim 6, wherein the negative electrode includes a negative electrode active material, and the negative electrode active material is a mixture and/or composite of graphite particles and particles containing silicon (Si) or tin (Sn). liquid battery. The nonaqueous electrolyte battery according to any one of claims 6 to 9, wherein the positive electrode contains a positive electrode active material, and the positive electrode active material contains a metal oxide represented by the following compositional formula (1).
Li _a1 Ni _b1 Co _c1 M _d1 O ₂ ...(1)
(In the above formula (1), a1, b1, c1 and d1 are 0.90≦a1≦1.10, 0.50≦b1≦0.98, 0.01≦c1<0.50, 0.01 Indicates a numerical value of ≦d1<0.50, and satisfies b1+c1+d1=1.M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er.)