JP2013157305A - Nonaqueous electrolyte and nonaqueous electrolyte battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery which suppresses characteristic deterioration and gas generation during high-temperature storage of the nonaqueous electrolyte battery and has excellent charge/discharge characteristics under a high current density.SOLUTION: A nonaqueous electrolyte is used which contains (A) a compound having at least two isocyanate groups in the molecule and (B) a compound represented by formula (1).

Description

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

  With the rapid progress of portable electronic devices such as mobile phones and notebook personal computers, there is an increasing demand for higher capacities for batteries used for the main power source and backup power source, such as nickel cadmium batteries and nickel Non-aqueous electrolyte batteries such as lithium ion secondary batteries having higher energy density than hydrogen batteries have attracted attention.

As an electrolytic solution of the lithium ion secondary battery, an electrolyte such as LiPF ₆ , LiBF ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiCF ₃ (CF ₂ ) ₃ SO ₃ is used as a high dielectric constant such as ethylene carbonate or propylene carbonate. A typical example is a non-aqueous electrolyte solution dissolved in a mixed solvent of a solvent and a low-viscosity solvent such as dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate.

In addition, as a negative electrode active material of a lithium ion secondary battery, a carbonaceous material capable of occluding and releasing lithium ions is mainly used, and natural graphite, artificial graphite, amorphous carbon, etc. are listed as representative examples. It is done. Furthermore, metal or alloy negative electrodes using silicon, tin or the like for increasing the capacity are also known. As the positive electrode active material, a transition metal composite oxide capable of mainly inserting and extracting lithium ions is used, and representative examples of the transition metal include cobalt, nickel, manganese, iron and the like.
Such a lithium ion secondary battery uses a highly active positive electrode and negative electrode, and it is known that the charge / discharge capacity decreases due to a side reaction between the electrode and the electrolyte, improving battery characteristics. Therefore, various studies have been made on non-aqueous solvents and electrolytes.

Patent Documents 1 and 2 propose that by adding a compound having an isocyanate group to a non-aqueous electrolyte, the decomposition reaction of the solvent on the negative electrode is suppressed, and the cycle characteristics of the battery are improved.
In Patent Document 3, by using a non-aqueous electrolyte solution containing an alkyne derivative, the alkyne derivative is decomposed on the surface of the carbon negative electrode to form a passive film. Further, the decomposition product is oxidatively decomposed on the positive electrode, thereby suppressing the oxidative decomposition of the electrolytic solution. It has been proposed to improve the charge / discharge cycle life.

Japanese Unexamined Patent Publication No. 2005-259541 Japanese Unexamined Patent Publication No. 2006-164759 Japanese Unexamined Patent Publication No. 2000-195545

However, the demand for higher performance of batteries in recent years is increasing, and it is required to achieve various battery characteristics such as high capacity, high temperature storage characteristics, and cycle characteristics at a high level.
As a method for increasing the capacity, for example, a method of increasing the density by pressurizing the active material layer of the electrode and reducing the volume occupied by the active material other than the active material inside the battery as much as possible, or expanding the usage range of the positive electrode to a high potential The method to use is being studied. However, if the active material layer of the electrode is pressurized and densified, it becomes difficult to use the active material uniformly, and some lithium precipitates due to a non-uniform reaction or deterioration of the active material is promoted. The problem that sufficient characteristics cannot be obtained is likely to occur. Further, when the use range of the positive electrode is expanded to be used up to a high potential, the activity of the positive electrode is further increased, and the problem that the deterioration is accelerated by the reaction between the positive electrode and the electrolytic solution is likely to occur. In particular, when stored under high temperature conditions in a charged state, it is known that the battery capacity decreases due to a side reaction between the electrode and the electrolyte solution. In order to improve storage characteristics, various nonaqueous solvents and electrolytes are used. Consideration has been made.
Further, the increase in capacity reduces the gap in the battery, and there is a problem that the internal pressure of the battery increases remarkably even when a small amount of gas is generated by the decomposition of the electrolyte.

Although suppression of the deterioration of the battery characteristics is required, when the isocyanate compound described in Patent Documents 1 to 2 is contained in the nonaqueous electrolytic solution, the side reaction of the additive simultaneously proceeds on the positive electrode. Further, even if the non-aqueous electrolyte contains the additive described in Patent Document 3, the reaction of the electrolyte at the negative electrode cannot be completely suppressed, and the high-temperature storage characteristics are not yet satisfactory. It was.
Therefore, the present invention has been made in view of the above problems, and in a non-aqueous electrolyte battery, a non-aqueous electrolyte that suppresses property deterioration and gas generation during high-temperature storage, and the non-aqueous electrolyte It is an object to provide a used battery.

  As a result of various studies to achieve the above-mentioned object, the present inventors have found that a compound having at least two isocyanate groups in the molecule and a compound represented by the formula (1) (hereinafter, suitably at least in the molecule) It has been found that the above-mentioned problems can be solved by incorporating a compound having a single triple bond in a non-aqueous electrolyte solution, and the present invention described later has been completed.

（式（１）中、Ｒ^１、Ｒ^２は各々独立に、水素原子、ハロゲン原子、または置換基を有してもよい有機基であり、それぞれ同一であっても異なっていてもよい。）
（ｂ）前記一般式（１）で示される化合物を非水系電解液中に０．０１質量％以上５質量％以下含有することを特徴とする（ａ）に記載の非水系電解液。
（ｃ）前記一般式（１）中、Ｒ^１若しくはＲ^２のいずれか、または両方がＳ＝Ｏ基を１つ以上含む有機基であることを特徴とする（ａ）または（ｂ）に記載の非水系電解液。
（ｄ）前記分子内に少なくとも２つのイソシアネート基を有する化合物が、ヘキサメチレンジイソシアネート、１，３−ビス（イソシアナトメチル）シクロヘキサン、ジシクロヘキシルメタン−４,４’−ジイソシアネート、ビシクロ［２．２．１］ヘプタン−２，５−ジイルビス（メチルイソシアネート）、ビシクロ［２．２．１］ヘプタン−２，６−ジイルビス（メチルイソシアネート）、ジイソシアン酸イソホロン、２，２，４−トリメチルヘキサメチレンジイソシアナート、２，４，４−トリメチルヘキサメチレンジイソシアナート及びそれらにより誘導されるポリイソシアネート化合物よりなる群から選ばれる少なくとも１種の化合物を含むことを特徴とする（ａ）乃至（ｃ）のいずれか１つに記載の非水系電解液。
（ｅ）フッ素原子を有する環状カーボネート、炭素−炭素不飽和結合を有する環状カーボネート、モノフルオロリン酸塩、及びジフルオロリン酸塩よりなる群から選ばれる少なくとも１種の化合物を更に含有することを特徴とする（ａ）乃至（ｄ）のいずれか１つに記載の非水系電解液。
（ｆ）フッ素原子を有する環状カーボネートが、モノフルオロエチレンカーボネート、４，４−ジフルオロエチレンカーボネート、及び４，５−ジフルオロエチレンカーボネートよりなる群から選ばれる少なくとも１種の化合物を含み、炭素−炭素不飽和結合を有する環状カーボネートが、ビニレンカーボネート、ビニルエチレンカーボネート、及びエチニルエチレンカーボネートよりなる群から選ばれる少なくとも１種の化合物を含むことを特徴とする請求項（ｅ）に記載の非水系電解液。
（ｇ）リチウムイオンを吸蔵・放出可能な負極及び正極、並びに非水系電解液を含む非水系電解液二次電池であって、該非水系電解液が（ａ）乃至（ｆ）のいずれか１つに記載の非水系電解液であることを特徴とする非水系電解液二次電池。 The gist of the present invention is as follows.
(A) A non-aqueous electrolyte solution for a non-aqueous electrolyte battery comprising a positive electrode and a negative electrode capable of inserting and extracting metal ions, the non-aqueous electrolyte solution together with an electrolyte and a non-aqueous solvent,
(A) A non-aqueous electrolyte containing a compound having at least two isocyanate groups in the molecule and (B) a compound represented by the following formula (1).

(In formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, or an organic group that may have a substituent, and may be the same or different.)
(B) The non-aqueous electrolyte solution according to (a), wherein the non-aqueous electrolyte solution contains the compound represented by the general formula (1) in an amount of 0.01% by mass to 5% by mass.
(C) In the general formula (1), either R ¹ or R ² or both are organic groups containing one or more S═O groups, as described in (a) or (b) Non-aqueous electrolyte.
(D) The compound having at least two isocyanate groups in the molecule is hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-4,4′-diisocyanate, bicyclo [2.2.1 ] Heptane-2,5-diylbis (methyl isocyanate), bicyclo [2.2.1] heptane-2,6-diylbis (methyl isocyanate), isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, Any one of (a) to (c), comprising at least one compound selected from the group consisting of 2,4,4-trimethylhexamethylene diisocyanate and a polyisocyanate compound derived therefrom. Non-aqueous electrolyte described in 1.
(E) It further contains at least one compound selected from the group consisting of a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a monofluorophosphate, and a difluorophosphate. The non-aqueous electrolyte solution according to any one of (a) to (d).
(F) the cyclic carbonate having a fluorine atom contains at least one compound selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate, The non-aqueous electrolyte solution according to claim (e), wherein the cyclic carbonate having a saturated bond contains at least one compound selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, and ethynyl ethylene carbonate.
(G) A non-aqueous electrolyte secondary battery including a negative electrode and a positive electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is any one of (a) to (f) A non-aqueous electrolyte secondary battery, which is the non-aqueous electrolyte solution described in 1.

ADVANTAGE OF THE INVENTION According to this invention, the non-aqueous electrolyte battery which suppressed the characteristic deterioration at the time of high temperature preservation | save of a non-aqueous electrolyte battery and gas generation, and has the outstanding charging / discharging characteristic under a high current density can be provided. .
The non-aqueous electrolyte secondary battery produced using the non-aqueous electrolyte of the present invention and the non-aqueous electrolyte secondary battery of the present invention are capable of capacity degradation and gas generation during high temperature storage, under high current density. Although the action and principle that can improve the charge / discharge characteristics are not clear, it is considered as follows. However, the present invention is not limited to the operations and principles described below.
Usually, in the proposals represented by Patent Documents 1 and 2, the battery characteristics are improved by the reaction of the diisocyanate compound on the negative electrode. However, since the diisocyanate compound causes a side reaction on the positive electrode, the battery capacity decreases. Such a decrease proceeds in the same manner even in a compound having two or more isocyanate groups. Similarly, in the proposal typified by Patent Document 3, the additive acts even at the positive electrode, but the battery characteristics are deteriorated due to the adverse effect of the side reaction at the negative electrode. Therefore, use of these additives alone has not been satisfactory as battery characteristics. Furthermore, attempts have been made to improve the long-term stability of the battery by using a compound containing an isocyanate group in the molecule. However, depending on the type of isocyanate compound, the type of additive combined therewith, or the blending amount thereof may be sufficient. The battery performance was not satisfactory and the battery performance was not satisfactory.

  The present inventors pay attention to this point, and by using the non-aqueous electrolyte solution and the non-aqueous electrolyte battery according to the present invention, side reactions of these compounds are specifically suppressed, and battery characteristics are dramatically improved. I found out.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
In addition, “wt%”, “wt ppm”, “part by weight”, “mass%”, “mass ppm”, and “mass part” are synonymous with each other. In addition, when simply described as “ppm”, it means “ppm by weight”.

1. Non-aqueous electrolyte 1-1. The compound which has at least 2 isocyanate group in a molecule | numerator This invention is characterized by containing the compound which has at least 2 isocyanate group in a molecule | numerator in nonaqueous electrolyte solution.
The compound having at least two isocyanate groups in the molecule used in the present invention is not particularly limited as long as it is a compound having at least two isocyanate groups in the molecule. And an alkylene structure, a cycloalkylene structure, an aromatic hydrocarbon structure, an ether structure (—O—), or a compound having a halogenated structure thereof. In addition, a carbonyl group (—C (═O) —), a structure in which a carbonyl group and an alkylene group are linked, a sulfonyl group (—S (═O) —), a structure in which a sulfonyl group and an alkylene group are linked, and the like Also mentioned.

Specific examples of the compound having at least two isocyanate groups in the molecule include the following compounds.
Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-diisocyanate Natopropane, 1,4-diisocyanato-2-butene, 1,4-diisocyanato-2-fluorobutane, 1,4-diisocyanato-2,3-difluorobutane, 1,5-diisocyanato-2-pentene, 1,5 -Diisocyanato-2-methylpentane, 1,6-diisocyanato-2-hexene, 1,6-diisocyanato-3-hexene, 1,6 Diisocyanato-3-fluorohexane, 1,6-diisocyanato-3,4-difluorohexane, toluene diisocyanate, xylene diisocyanate, tolylene diisocyanate, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanato) Methyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, dicyclohexylmethane-1,1 ′ Diisocyanate, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane-3,3′-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, bicyclo [2.2.1] heptane-2, 5-diylbis (methylisocyanate), bicyclo [2.2.1] heptane-2,6-diylbis (methylisocyanate), isophorone diisocyanate, carbonyl diisocyanate, 1,4-diisocyanatobutane-1,4-dione, 1,5-diisocyanatopentane-1,5-dione, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate.

  Among these, monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-4,4′-diisocyanate, bicyclo [2.2.1] heptane-2,5-diylbis (methylisocyanate), bicyclo [2.2.1] heptane- 2,6-diylbis (methylisocyanate), isophorone diisocyanate, 2,2,4-trimethylhexamethyle Diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate are preferred from the viewpoint of improving storage characteristics.

The isocyanate compound used in the present invention may be a trimer compound derived from a compound having at least two isocyanate groups in the molecule, or an aliphatic polyisocyanate obtained by adding a polyhydric alcohol thereto. Examples include biurets, isocyanurates, adducts, and bifunctional type modified polyisocyanates represented by the basic structures of the following general formulas (1-1) to (1-4) (the following general formula (1-1) ) To (1-4), R and R ′ are each independently an arbitrary hydrocarbon group).

  The compound having at least two isocyanate groups in the molecule used in the present invention also includes so-called blocked isocyanate which is blocked with a blocking agent to enhance storage stability. Examples of the blocking agent include alcohols, phenols, organic amines, oximes, and lactams. Specific examples include n-butanol, phenol, tributylamine, diethylethanolamine, methyl ethyl ketoxime, and ε-caprolactam. Etc.

  In order to promote a reaction based on a compound having at least two isocyanate groups in the molecule and obtain a higher effect, a metal catalyst such as dibutyltin dilaurate or the like, 1,8-diazabicyclo [5.4.0] undecene- It is also preferable to use an amine catalyst such as 7 in combination.

As the compound having at least two isocyanate groups in the molecule, one type may be used alone, or two or more types may be used in any combination and ratio. There is no limitation on the compounding amount of the compound having at least two isocyanate groups in the molecule with respect to the whole non-aqueous electrolyte of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired. On the other hand, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass. It is contained at a concentration of not more than%. When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved.

式（１）中、Ｒ^１、Ｒ^２は各々独立に、水素原子、ハロゲン原子、または置換基を有してもよい有機基であり、それぞれ同一であっても異なっていてもよい。 1-2. The compound represented by the formula (1) The present invention is also characterized by containing a compound represented by the following formula (1) in a nonaqueous electrolytic solution.

In formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, or an organic group that may have a substituent, and may be the same or different.

Here, the organic group represents a functional group composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms and halogen atoms. Specific examples include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, alkoxy groups, cyano groups, isocyanato groups, ether groups, carbonate groups, carbonyl groups, sulfonyl groups, phosphoryl groups, and the like.
Specific examples of the substituent include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, alkoxy groups, cyano groups, isocyanato groups, ether groups, carbonate groups, carbonyl groups, carboxyl groups which may be substituted with halogen atoms. Group, sulfonyl group, phosphoryl group and the like.

In the formula (1), it is preferable that either one or both of R ^{1 and} R ² is an organic group containing one or more S═O groups. By having an S═O group, it becomes easy to act on the positive electrode, and a side reaction on the positive electrode caused by a decomposition product of a compound having at least one triple bond in the molecule is suppressed.
The molecular weight of the compound represented by the formula (1) is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 100 or more, more preferably 130 or more, still more preferably 145 or more, and is 500 or less, preferably 300 or less, and more preferably 270 or less. If it is this range, it will be easy to ensure the solubility of the compound shown by Formula (1) with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed.

Specific examples of the compound represented by the formula (1) include the following compounds.
1-pentyne, 2-pentyne, 1-hexyne, 2-hexyne, 3-hexyne, 1-heptin, 2-heptin, 3-heptin, 1-octyne, 2-octyne, 3-octyne, 4-octyne, 1- Nonin, 2-nonine, 3-nonine, 4-nonine, 1-dodecin, 2-dodecin, 3-dodecin, 4-dodecin, 5-dodecin, phenylacetylene, 1-phenyl-1-propyne, 1-phenyl-2 -Propyne, 1-phenyl-1-butyne, 4-phenyl-1-butyne, 4-phenyl-1-butyne, 1-phenyl-1-pentyne, 5-phenyl-1-pentyne, 1-phenyl-1-hexyne , Hydrocarbon compounds such as 6-phenyl-1-hexyne, diphenylacetylene, 4-ethynyltoluene, dicyclohexylacetylene; 2-propynylmethylcar 2-propynylethyl carbonate, 2-propynylpropyl carbonate, 2-propynylbutyl carbonate, 2-propynylphenyl carbonate, 2-propynylcyclohexyl carbonate, di-2-propynyl carbonate, 1-methyl-2-propynylmethyl carbonate, 1 1-dimethyl-2-propynylmethyl carbonate, 2-butynylmethyl carbonate, 3-butynylmethyl carbonate, 2-pentynylmethyl carbonate, 3-pentynylmethyl carbonate, 4-pentynylmethyl carbonate, etc. 2-butyne-1,4-diol dimethyl dicarbonate, 2-butyne-1,4-diol diethyl dicarbonate, 2-butyne-1,4-diol dipropyl dicarbonate , 2-butyne-1,4-diol dibutyl carbonate, 2-butyne-1,4-diol diphenyl carbonate, dicarbonate such as 2-butyne-1,4-diol and dicyclohexyl carbonate;

  2-propynyl acetate, 2-propynyl propionate, 2-propynyl butyrate, 2-propynyl benzoate, -2-propynyl cyclohexylcarboxylate, acetic acid-1, 1-dimethyl-2-propynyl, propionic acid-1 1-dimethyl-2-propynyl, butyric acid-1, 1-dimethyl-2-propynyl, benzoic acid-1, 1-dimethyl-2-propynyl, cyclohexylcarboxylic acid-1, 1-dimethyl-2-propynyl, acetic acid 2-butynyl, acetic acid-3-butynyl, acetic acid-2-pentynyl, acetic acid-3-pentynyl, acetic acid-4-pentynyl, 2-propanoic acid methyl, 2-propanoic acid ethyl, 2-propionic acid propyl, 2-propionic acid Vinyl, 2-propionic acid-2-propenyl, 2-propionic acid-2-butenyl, 2-propionic acid-3-butenyl, 2- Methyl butyrate, ethyl 2-butyrate, 2-propyl butyrate, vinyl 2-butyrate, 2-butynoic acid-2-propenyl, 2-butynoic acid-2-butenyl, 2-butynoic acid-3-butenyl, 3 Methyl butyrate, ethyl 3-butyrate, propyl 3-butyrate, vinyl 3-butyrate, 3-butynoic acid-2-propenyl, 3-butynoic acid-2-butenyl, 3-butynoic acid-3-butenyl, 2-pentynoic acid methyl, 2-pentynoic acid ethyl, 2-pentynoic acid propyl, 2-pentynoic acid vinyl, 2-pentynoic acid-2-propenyl, 2-pentynoic acid-2-butenyl, 2-pentynoic acid-3-butenyl Methyl 3-pentynoate, ethyl 3-pentynoate, propyl 3-pentynoate, vinyl 3-pentynoate, 3-pentynoic acid-2-propenyl, 3-pentynoic acid-2-butenyl, -Pentynoic acid-3-butenyl, 4-pentynoic acid methyl, 4-pentynoic acid ethyl, 4-pentynoic acid propyl, 4-pentynoic acid vinyl, 4-pentynoic acid-2-propenyl, 4-pentynoic acid-2-butenyl, 4-pentynoic acid-3-butenyl, 2- (methanesulfonyloxy) propionic acid-2-propynyl, 2- (methanesulfonyloxy) propionic acid-3-butynyl, methanesulfonyloxyacetic acid-2-propynyl, methanesulfonyloxyacetic acid Monobutyric acid esters such as -3-butynyl; 2-butyne-1,4-diol diacetate, 2-butyne-1,4-diol dipropionate, 2-butyne-1,4-diol dibutyrate, 2-butyne- 1,4-diol dibenzoate, 2-butyne-1,4-diol dicyclohexane Dicarboxylic acid esters such as Rubokishireto;

  Methyl-2-propynyl oxalate, ethyl-2-propynyl oxalate, propyl-2-propynyl oxalate, 2-propynyl oxalate (vinyl), allyl-2-propynyl oxalate, di-2-propynyl oxalate, 2-butynyl oxalate methyl, 2-butynyl oxalate (ethyl), 2-butynyl oxalate (propyl), -2-butynyl oxalate (vinyl), allyl-2-butynyl oxalate, di-oxalate 2-butynyl, oxalate-3-butynyl (methyl), oxalate-3-butynyl (ethyl), oxalate-3-butynyl (propyl), oxalate-3-butynyl (vinyl), allyl oxalate-3- Oxalic acid diesters such as butynyl and di-3-butynyl oxalate; methyl-2-propynylsulfone, ethyl-2-propynylsulfone, Lopyl-2-propynylsulfone, 2-propynylvinylsulfone, 2-propenyl-2-propynylsulfone, di-2-propynylsulfone, 3-butenyl-2-propynylsulfone, 3-butenyl-2-propynylsulfone, 1,1 -Sulfone compounds such as dimethyl-2-propynyl vinyl sulfone and 1,1-dimethyl-2-propynyl-2-propenyl sulfone;

Methanesulfonic acid-2-propynyl, ethanesulfonic acid-2-propynyl, propanesulfonic acid-2-propynyl, p-toluenesulfonic acid-2-propynyl, cyclohexylsulfonic acid-2-propynyl, vinylsulfonic acid-2-propynyl, 2-propynylsulfonic acid-2-propynyl, 2-propynylsulfonic acid methyl, 2-propynylsulfonic acid ethyl, 2-propynylsulfonic acid butyl, 2-propynylsulfonic acid-2-propenyl, 2-propynylsulfonic acid-2-propynyl Methanesulfonic acid-1, 1-dimethyl-2-propynyl, ethanesulfonic acid-1, 1-dimethyl-2-propynyl, propanesulfonic acid-1, 1-dimethyl-2-propynyl, p-toluenesulfonic acid-1 1-dimethyl-2-propynyl, cyclohe Silsulfonic acid-1, 1-dimethyl-2-propynyl, vinylsulfonic acid-1, 1-dimethyl-2-propynyl, 2-propenylsulfonic acid-1, 1-dimethyl-2-propynyl, methanesulfonic acid-2-pentynyl Methanesulfonic acid-3-pentynyl, methanesulfonic acid-4-pentynyl, vinylsulfonic acid-2-butynyl, vinylsulfonic acid-3-butynyl, vinylsulfonic acid-2-pentynyl, vinylsulfonic acid-3-pentynyl, vinyl Sulfonic acid-4-pentynyl, 2-propenylsulfonic acid-2-butynyl, 2-propenylsulfonic acid-3-butynyl, 2-propenylsulfonic acid-2-pentynyl, 2-propenylsulfonic acid-3-pentynyl, 2-propenyl Sulfonic acid-4-pentynyl, 2-propynylsulfonic acid-2 Butynyl, 2-propynylsulfonic acid-3-butynyl, 2-propynylsulfonic acid-2-pentynyl, 2-propynylsulfonic acid-3-pentynyl, 2-propynylsulfonic acid-4-pentynyl, 2-oxoethanesulfonic acid-2 -Propynyl, 3-oxopropanesulfonic acid-2-propynyl, 4-oxobutanesulfonic acid-2-propynyl, 5-oxopentanesulfonic acid-2-propynyl, 6-oxohexanesulfonic acid-2-propynyl, 7-oxo Heptanesulfonic acid-2-propynyl, 3-oxopropoxymethanesulfonic acid-2-propynyl, 2-oxopropanesulfonic acid-2-propynyl, 3-oxobutanesulfonic acid-2-propynyl, 4-oxopentanesulfonic acid-2 -Propynyl, 5-oxohexanesulfonic acid 2-propynyl, 2-propynyl 6-oxoheptanesulfonate, 2-propynyl 7-oxooctanesulfonate, 2-propynyl 2-oxobutanesulfonate, 2-propynyl 3-oxopentanesulfonate, 4 -Oxohexanesulfonic acid-2-propynyl, 5-oxoheptanesulfonic acid-2-propynyl, 6-oxooctanesulfonic acid-2-propynyl, 7-oxononanesulfonic acid-2-propynyl, 2- (3-oxobutoxy ) -2-propynyl ethanesulfonate, 2-propynyl methanesulfonylmethanesulfonate, 2-propynyl 2- (methanesulfonyl) ethanesulfonate, 2-propynyl 3- (methanesulfonyl) propanesulfonate, 4- ( Methanesulfonyl) butanesulfonic acid-2-propynyl 5- (Methanesulfonyl) pentanesulfonic acid-2-propynyl, 6- (methanesulfonyl) hexanesulfonic acid-2-propynyl, ethanesulfonylmethanesulfonic acid-2-propynyl, 2- (ethanesulfonyl) ethanesulfonic acid-2- Propinyl, 3- (ethanesulfonyl) propanesulfonic acid-2-propynyl, 4- (ethanesulfonyl) butanesulfonic acid-2-propynyl, 5- (ethanesulfonyl) pentanesulfonic acid-2-propynyl, 6- (ethanesulfonyl) Hexanesulfonic acid-2-propynyl, trifluoromethanesulfonylmethanesulfonic acid-2-propynyl, 2- (trifluoromethanesulfonyl) ethanesulfonic acid-2-propynyl, 3- (trifluoromethanesulfonyl) propanesulfonic acid-2-propynyl 4- (trifluoromethanesulfonyl) butanesulfonic acid-2-propynyl, 5- (trifluoromethanesulfonyl) pentanesulfonic acid-2-propynyl, 6- (trifluoromethanesulfonyl) hexanesulfonic acid-2-propynyl, 2- ( 2- (Methanesulfonyl) ethoxy) ethanesulfonic acid-2-propynyl, benzenesulfonylmethanesulfonic acid-2-propynyl, 2- (benzenesulfonyl) ethanesulfonic acid-2-propynyl, 3- (benzenesulfonyl) propanesulfonic acid- 2-propynyl, 4- (benzenesulfonyl) butanesulfonic acid-2-propynyl, 5- (benzenesulfonyl) pentanesulfonic acid-2-propynyl, 6- (benzenesulfonyl) hexanesulfonic acid-2-propynyl, 4-methylbenze 2-propynyl sulfonylmethanesulfonate-2-propynyl 2- (4-methylbenzenesulfonyl) ethanesulfonate-2-propynyl 3- (4-methylbenzenesulfonyl) propanesulfonate, 4- (4-methyl) Benzenesulfonyl) butanesulfonic acid-2-propynyl, 5- (4-methylbenzenesulfonyl) pentanesulfonic acid-2-propynyl, 6- (4-methylbenzenesulfonyl) hexanesulfonic acid-2-propynyl, 4-fluorobenzenesulfonyl 2-propynyl methanesulfonate, 2-propynyl 2- (4-fluorobenzenesulfonyl) ethanesulfonate, 2-propynyl 3- (4-fluorobenzenesulfonyl) propanesulfonate, 4- (4-fluorobenzenesulfonyl) ) Butanesulfonic acid 2-propynyl, 5- (4-fluorobenzenesulfonyl) pentanesulfonic acid-2-propynyl, 6- (4-fluorobenzenesulfonyl) hexanesulfonic acid-2-propynyl, 2- (2-benzenesulfonylethoxy) ethanesulfonic acid 2-propynyl, methoxysulfonylmethanesulfonic acid-2-propynyl, 2- (methoxysulfonyl) ethanesulfonic acid-2-propynyl, 3- (methoxysulfonyl) propanesulfonic acid-2-propynyl, 4- (methoxysulfonyl) butane 2-propynyl sulfonate, 2-propynyl 5- (methoxysulfonyl) pentanesulfonate, 2-propynyl 6- (methoxysulfonyl) hexanesulfonate, 2-propynyl ethoxysulfonylmethanesulfonate, 2- (ethoxysulfone) Nyl) ethanesulfonic acid-2-propynyl, 3- (ethoxysulfonyl) propanesulfonic acid-2-propynyl, 4- (ethoxysulfonyl) butanesulfonic acid-2-propynyl, 5- (ethoxysulfonyl) pentanesulfonic acid-2- Propynyl, 6- (ethoxysulfonyl) hexanesulfonic acid-2-propynyl, 2- (2- (methoxysulfonyl) ethoxy) ethanesulfonic acid-2-propynyl, 2-propenyloxysulfonylmethanesulfonic acid-2-propynyl, 2- (2-propenyloxysulfonyl) ethanesulfonic acid-2-propynyl, 3- (2-propenyloxysulfonyl) propanesulfonic acid-2-propynyl, 4- (2-propenyloxysulfonyl) butanesulfonic acid-2′-propynyl, 5- (2-propenyl) Xylsulfonyl) pentanesulfonic acid-2-propynyl, 6- (2-propenyloxysulfonyl) hexanesulfonic acid-2-propynyl, 2- (2- (2-propenyloxysulfonyl) ethoxy) ethanesulfonic acid-2-propynyl, 2-propynyl dimethoxyphosphoryl methanesulfonate, 2-propynyl 2- (dimethoxyphosphoryl) ethanesulfonate, 2-propynyl 3- (dimethoxyphosphorylpropane) sulfonate, 4- (dimethoxyphosphoryl) butanesulfonate-2- Propinyl, 5- (dimethoxyphosphoryl) pentanesulfonic acid-2-propynyl, 6- (dimethoxyphosphoryl) hexanesulfonic acid-2-propynyl, diethoxyphosphorylmethanesulfonic acid-2-propynyl, 2- (diethoxyphosphoryl) Ethanesulfonic acid-2-propynyl, 3- (diethoxyphosphoryl) propanesulfonic acid-2-propynyl, 4- (diethoxyphosphoryl) butanesulfonic acid-2-propynyl, 5- (diethoxyphosphoryl) pentanesulfonic acid-2 -Propynyl, 6- (diethoxyphosphoryl) hexanesulfonic acid-2-propynyl, 2- (2- (dimethoxyphosphoryl) ethoxy) ethanesulfonic acid-2-propynyl, methoxy (methyl) phosphorylmethanesulfonic acid-2-propynyl, 2-propynyl 2- (methoxy (methyl) phosphoryl) ethanesulfonic acid-2-propynyl 3- (methoxy (methyl) phosphoryl) propanesulfonic acid-2-propynyl 4- (methoxy (methyl) phosphoryl) butanesulfonic acid , 5- (methoxy (methyl) phospho (Folyl) pentanesulfonic acid-2-propynyl, 6- (methoxy (methyl) phosphoryl) hexanesulfonic acid-2-propynyl, 2- (2- (methoxy (methyl) phosphoryl) ethoxy) ethanesulfonic acid-2-propynyl, ethoxy (Methyl) phosphorylmethanesulfonic acid-2-propynyl, 2- (ethoxy (methyl) phosphoryl) ethanesulfonic acid-2-propynyl, 3- (ethoxy (methyl) phosphoryl) propanesulfonic acid-2-propynyl, ethyl (methoxy) Phosphorylmethanesulfonic acid-2-propynyl, 2- (ethyl (methoxy) phosphoryl) ethanesulfonic acid-2-propynyl, 3- (ethyl (methoxy) phosphoryl) propanesulfonic acid-2-propynyl, dimethylphosphorylmethanesulfonic acid-2 -Propynyl, 2 (Dimethylphosphoryl) ethanesulfonic acid-2-propynyl, 3- (dimethylphosphoryl) propanesulfonic acid-2-propynyl, 4- (dimethylphosphoryl) butanesulfonic acid-2-propynyl, 5- (dimethylphosphoryl) pentanesulfonic acid- 2-propynyl, 6- (dimethylphosphoryl) hexanesulfonic acid-2-propynyl,
2- (2- (dimethylphosphoryl) ethoxy) ethanesulfonic acid-2-propynyl, methoxymethanesulfonic acid-2-propynyl, 2-methoxyethanesulfonic acid-2-propynyl, 3-methoxypropanesulfonic acid-2-propynyl, 2-Methoxybutanesulfonic acid-2-propynyl, 5-methoxypentanesulfonic acid-2-propynyl, 6-methoxyhexanesulfonic acid-2-propynyl, ethoxymethanesulfonic acid-2-propynyl, 2-ethoxyethanesulfonic acid-2 -Propynyl, 3-ethoxypropanesulfonic acid-2-propynyl, 4-ethoxybutanesulfonic acid-2-propynyl, 5-ethoxypentanesulfonic acid-2-propynyl, 6-ethoxyhexanesulfonic acid-2-propynyl, 2- ( 2-methoxyethoxy) ethane 2-propynyl sulfonic acid, 2-propynyl formyloxymethanesulfonate, 2-propynyl 2- (formyloxy) ethanesulfonate, 2-propynyl 3- (formyloxy) propanesulfonate, 4- (formyloxy) ) -2-propynyl butanesulfonic acid, 2-propynyl 5- (formyloxy) pentanesulfonic acid, 2-propynyl 6- (formyloxy) hexanesulfonic acid, 2- (2- (formyloxy) ethoxy) ethanesulfone Acid-2-propynyl, acetyloxymethanesulfonic acid-2-propynyl, 2- (acetyloxy) ethanesulfonic acid-2-propynyl, 3- (acetyloxy) propanesulfonic acid-2-propynyl, 4- (acetyloxy) 2-propynyl butanesulfonate, 5- (acetyl Xyl) pentanesulfonic acid-2-propynyl, 6- (acetyloxy) hexanesulfonic acid-2-propynyl, propionyloxymethanesulfonic acid-2-propynyl, 2- (propionyloxy) ethanesulfonic acid-2-propynyl, 3- (Propionyloxy) propanesulfonic acid-2-propynyl, 4- (propionyloxy) butanesulfonic acid-2-propynyl, 5- (propionyloxy) pentanesulfonic acid-2-propynyl, 6- (propionyloxy) hexanesulfonic acid- 2-propynyl, 2- (2- (acetyloxy) ethoxy) ethanesulfonic acid-2-propynyl, methanesulfonyloxymethanesulfonic acid-2-propynyl, 2- (methanesulfonyloxy) ethanesulfonic acid-2-propynyl, 3 -(Methanesulfur 2- (propynyl) 4- (methanesulfonyloxy) butanesulfonic acid, 2-propynyl, 5- (methanesulfonyloxy) pentanesulfonic acid, 6- (methanesulfonyloxy) hexanesulfonic acid 2-propynyl, ethanesulfonyloxymethanesulfonic acid-2-propynyl, 2- (ethanesulfonyloxy) ethanesulfonic acid-2-propynyl, 3- (ethanesulfonyloxy) propanesulfonic acid-2-propynyl, 4- (ethane Sulfonyloxy) butanesulfonic acid-2-propynyl, 5- (ethanesulfonyloxy) pentanesulfonic acid-2-propynyl, 5- (ethanesulfonyloxy) hexanesulfonic acid-2-propynyl, trifluoromethanesulfonyloxymeta 2-propynyl sulfonate, 2- (trifluoromethanesulfonyloxy) ethanesulfonic acid-2-propynyl, 3- (trifluoromethanesulfonyloxy) propanesulfonic acid-2-propynyl, 4- (trifluoromethanesulfonyloxy) butanesulfonic acid 2-propynyl, 5- (trifluoromethanesulfonyloxy) pentanesulfonic acid-2-propynyl, 6- (trifluoromethanesulfonyloxy) hexanesulfonic acid-2-propynyl, 2- (2- (methanesulfonyloxy) ethoxy) ethane 2-propynyl sulfonate, 2-propynyl dimethoxyphosphoryloxymethanesulfonate, 2-propynyl ethanesulfonate, 2- (dimethoxyphosphoryloxy) propane 2-propynyl sulfonic acid, 2- (dimethoxyphosphoryloxy) butanesulfonic acid-2-propynyl, 5- (dimethoxyphosphoryloxy) pentanesulfonic acid-2-propynyl, 6- (dimethoxyphosphoryloxy) hexanesulfonic acid-2- Propynyl, diethoxyphosphoryloxymethanesulfonic acid-2-propynyl, 2- (diethoxyphosphoryloxy) ethanesulfonic acid-2-propynyl, 3- (diethoxyphosphoryloxy) propanesulfonic acid-2-propynyl, 4- (di- Ethoxyphosphoryloxy) butanesulfonic acid-2-propynyl, 5- (diethoxyphosphoryloxy) pentanesulfonic acid-2-propynyl, 6- (diethoxyphosphoryloxy) hexanesulfonic acid-2-propynyl, 2- (2- ( Dimethoxyphos Folyloxy) ethoxy) ethanesulfonic acid-2-propynyl, methoxy (methyl) phosphoryloxymethanesulfonic acid-2-propynyl, 2- (methoxy (methyl) phosphoryloxy) ethanesulfonic acid-2-propynyl, 3- (methoxy (methyl) ) Phosphoryloxy) propanesulfonic acid-2-propynyl, 4- (methoxy (methyl) phosphoryloxy) butanesulfonic acid-2-propynyl, 5- (methoxy (methyl) phosphoryloxy) pentanesulfonic acid-2-propynyl, 6- (Methoxy (methyl) phosphoryloxy) hexanesulfonic acid-2-propynyl, 2- (2- (methoxy (methyl) phosphoryloxy) ethoxy) ethanesulfonic acid-2-propynyl, ethoxy (methyl) phosphoryloxymethanesulfonic acid-2 -Propi 2- (ethoxy (methyl) phosphoryloxy) ethanesulfonic acid-2-propynyl, 3- (ethoxy (methyl) phosphoryloxy) propanesulfonic acid-2-propynyl, ethyl (methoxy) phosphoryloxymethanesulfonic acid-2- Propynyl, 2- (ethyl (methoxy) phosphoryloxy) ethanesulfonic acid-2-propynyl, 3- (ethyl (methoxy) phosphoryloxy) propanesulfonic acid-2-propynyl, dimethylphosphoryloxymethanesulfonic acid-2-propynyl, 2 -(Dimethylphosphoryloxy) ethanesulfonic acid-2-propynyl, 3- (dimethylphosphoryloxy) propanesulfonic acid-2-propynyl, 4- (dimethylphosphoryloxy) butanesulfonic acid-2-propynyl, 5- (dimethylphosphoryloxy) (I) monosulfonic acid esters such as 2-propynyl pentanesulfonic acid, 2-propynyl 6- (dimethylphosphoryloxy) hexanesulfonic acid, 2- (2- (dimethylphosphoryloxy) ethoxy) ethanesulfonic acid-2-propynyl ;

  2-butyne-1,4-diol dimethanesulfonate, 2-butyne-1,4-diol dipropanesulfonate, 2-butyne-1,4-diol di-p-toluenesulfonate, 2-butyne-1,4- Diol dicyclohexanesulfonate, 2-butyne-1,4-diol divinylsulfonate, 2-butyne-1,4-diol diallylsulfonate, 2-butyne-1,4-diol dipropynylsulfonate, methane-1,1-disulfonic acid Di (2-propynyl), ethane-1,2-disulfonic acid di (2-propynyl), propane-1,3-disulfonic acid di (2-propynyl), butane-1,4-disulfonic acid di (2-propynyl) ), Pentane-1,5-disulfonic acid di (2-propynyl), hexane-1,6-disulfonic acid di ( -Propynyl), disulfonic acid esters such as 2,2'-oxydiethanesulfonic acid di (2-propynyl); methyl-2-propynyl sulfate, ethyl-2-propynyl sulfate, propyl-2-propynyl sulfate, vinyl-2 -Propynyl sulfate, 2-propenyl 2-propynyl sulfate, di-2-propynyl sulfate, 2-propenyl-1,1-dimethyl-2-propynyl sulfate, 3-butenyl-2-propynyl sulfate and 3-butenyl-1,1 -Sulfate esters such as dimethyl-2-propynylsulfuric acid; methyl (2-propynyl) (vinyl) phosphine oxide, divinyl (2-propynyl) phosphine oxide, di (2-propynyl) (vinyl) phosphine oxide, di (2-propenyl) ) 2 (-propynyl) phosphine oxide, di (2-propynyl) (2-propene) Le) phosphine oxide, di (3-butenyl) (2-propynyl) phosphine oxide, and di (2-propynyl) (3-butenyl) phosphine oxide, such as phosphine oxides;

Methyl (2-propenyl) phosphinic acid-2-propynyl, 2-butenyl (methyl) phosphinic acid-2-propynyl, di (2-propenyl) phosphinic acid-2-propynyl, di (3-butenyl) phosphinic acid-2- Propinyl, methyl (2-propenyl) phosphinic acid-1,1-dimethyl-2-propynyl, 2-butenyl (methyl) phosphinic acid-1,1-dimethyl-2-propynyl, di (2-propenyl) phosphinic acid-1 , 1-dimethyl-2-propynyl, and di (3-butenyl) phosphinic acid-1,1-dimethyl-2-propynyl, methyl (2-propynyl) phosphinic acid-2-propenyl, methyl (2-propynyl) phosphinic acid -3-butenyl, di (2-propynyl) phosphinic acid-2-propenyl, di (2-propynyl) phosphine Phosphonic acid esters such as 3-butenyl acid, 2-propynyl (2-propenyl) phosphinic acid-2-propenyl, and 2-propynyl (2-propenyl) phosphinic acid-3-butenyl; methyl 2-propenylphosphonate 2-propynyl, 2-butenylphosphonic acid methyl-2-propynyl, 2-propenylphosphonic acid-2-propynyl (-2-propenyl), 3-butenylphosphonic acid-3-butenyl (-2-propynyl), 2-propenylphosphonic acid -1,1-dimethyl-2-propynyl (methyl), 2-butenylphosphonic acid-1,1-dimethyl-2-propynyl (methyl), 2-propenylphosphonic acid-1,1-dimethyl-2-propynyl (-2) -Propenyl), and 3-butenylphosphonic acid-3-butenyl (-1,1-dimethyl-) -Propynyl), methylphosphonic acid-2-propynyl (-2-propenyl), methylphosphonic acid-3-butenyl (-2-propynyl), methylphosphonic acid-1,1-dimethyl-2-propynyl (-2-propenyl), methylphosphone Acid-3-butenyl (-1,1-dimethyl-2-propynyl), ethylphosphonic acid-2-propynyl (-2-propenyl), ethylphosphonic acid-3-butenyl (-2-propynyl), ethylphosphonic acid- Phosphonic acid esters such as 1,1-dimethyl-2-propynyl (-2-propenyl) and ethylphosphonic acid-3-butenyl (-1,1-dimethyl-2-propynyl); methyl phosphate (-2-propenyl) ) (-2-propynyl), ethyl phosphate (-2-propenyl) (-2-propynyl), 2-butenyl phosphate (Methyl) (-2-propynyl), 2-butenyl (ethyl) phosphate (-2-propynyl) phosphate, 1,1-dimethyl-2-propynyl (methyl) phosphate (-2-propenyl) phosphate, phosphoric acid -1,1-dimethyl-2-propynyl (ethyl) (-2-propenyl), 2-butenyl phosphate (-1,1-dimethyl-2-propynyl) (methyl), and 2-butenyl phosphate ( (Ethyl) (-1,1-dimethyl-2-propynyl) and the like.

Among these, a compound having an alkynyloxy group is preferable because it reacts with a compound having at least two isocyanate groups in the molecule to form a negative electrode film more stably.
Furthermore, 2-propynylmethyl carbonate, di-2-propynyl carbonate, 2-butyne-1,4-diol dimethyl dicarbonate, 2-propynyl acetate, 2- (methanesulfonyloxy) propionate-2-propynyl, 2- Butyne-1,4-diol diacetate, methyl-2-propynyl oxalate, di-2-propynyl oxalate, -2-propynyl methanesulfonate, 2-propynyl vinylsulfonate, 2-propenylsulfonate-2- More preferable are compounds such as propynyl, 2-butyne-1,4-diol dimethanesulfonate, 2-butyne-1,4-diol divinylsulfonate, 2-butyne-1,4-diol diallylsulfonate, and methanesulfone. Acid-2-propynyl, vinylsulfonic acid-2-pro Alkenyl, 2-propenyl sulfonic acid-2-propynyl, 2- (methanesulfonyloxy) compounds such as propionic acid-2-propynyl is particularly preferred from the viewpoint of storage property improvement.

  The compound represented by the formula (1) may be included singly or in combination of two or more in the nonaqueous electrolytic solution of the present invention. The content of the compound represented by the formula (1) in the nonaqueous electrolytic solution (in the case of two or more types) is 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0. .1% by mass or more, and usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less. If this concentration is too low, the chemical and physical stability of the film may be insufficient. If the concentration is too high, the insulating properties of the film may increase, and the discharge capacity may decrease due to increased resistance. When the content of the compound represented by the formula (1) is in the above range, a synergistic effect with the compound having at least two isocyanate groups in the molecule can be easily obtained, and the reductive decomposition reaction of the nonaqueous solvent that occurs at the time of charging can be further improved. Therefore, the battery life can be improved such as high-temperature storage characteristics and cycle characteristics, the charge / discharge efficiency of the battery can be improved, and the low-temperature characteristics can be improved.

  The mass ratio of the compound having at least two isocyanate groups in the molecule to be contained in the non-aqueous electrolyte solution of the present invention and the compound represented by formula (1) is such that the content of the compound represented by formula (1) is 50:50. As mentioned above, Preferably it is 40:60 or more, More preferably, it is 35:65 or more, 1:99 or less, Preferably it is 10:90 or less, More preferably, it is 20:80. If it is this range, a battery characteristic, especially a storage characteristic can be improved significantly. Although this principle is not clear, it is considered that the side reaction of the additive on the electrode can be minimized by mixing at this ratio.

1-3. A cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a monofluorophosphate, and a difluorophosphate. Those containing at least one compound selected from the group consisting of cyclic carbonates having an unsaturated bond, monofluorophosphates and difluorophosphates are preferred. It is because the side reaction caused by each additive can be efficiently suppressed by using these together.
Furthermore, the cyclic carbonate having a fluorine atom and the cyclic carbonate having a carbon-carbon unsaturated bond form a stable protective film on the surface of the compound represented by the formula (1) and the negative electrode, This is more preferable because the reaction can be suppressed and high-temperature storage characteristics and cycle characteristics can be improved.

1-3-1. The cyclic carbonate having a fluorine atom The cyclic carbonate having a fluorine atom (hereinafter sometimes referred to as “fluorinated cyclic carbonate”) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.

  Examples of the fluorinated cyclic carbonate include a fluorinated product of a cyclic carbonate having an alkylene group having 2 to 6 carbon atoms and a derivative thereof, a fluorinated ethylene carbonate substituted with a substituent having an aromatic ring or a carbon-carbon double bond, and Examples thereof include fluorinated ethylene carbonate and derivatives thereof, and fluorinated vinylene carbonate and derivatives thereof. Examples of the derivatives of fluorinated ethylene carbonate include fluorinated ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Of these, ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferred. Examples of the fluorinated vinylene carbonate derivative include fluorinated vinylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Of these, vinylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferable.

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- (fluoro Methyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene -Bonate, 4,4-difluoro-5,5-dimethylethylene carbonate, 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene Carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-fluoro-4-vinyl ethylene carbonate, 4-fluoro-4-allyl ethylene carbonate, 4-fluoro-5-vinyl ethylene carbonate, 4-fluoro-5-allyl ethylene Carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene Carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5 -Diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4-phenylethylene carbonate, etc. Can be mentioned.

Among them, a saturated cyclic carbonate is preferable from the stability of the compound, and at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate and 4,5-difluoroethylene carbonate gives high ionic conductivity. And it is more preferable at the point which forms an interface protective film suitably.
A fluorinated cyclic carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The content of the fluorinated cyclic carbonate is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and preferably 1% by mass or more with respect to the non-aqueous electrolyte solution. It is 10 mass% or less, More preferably, it is 5 mass% or less, More preferably, it is 3 mass% or less. The blending amount when fluorinated cyclic carbonate is used as the non-aqueous solvent is preferably 100% by volume in the non-aqueous solvent, preferably 1% by volume or more, more preferably 5% by volume or more, and further preferably 10% by volume or more. Moreover, it is preferably 50% by volume or less, more preferably 35% by volume or less, and further preferably 25% by volume or less.
If it is within the above range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristic improvement effect, and avoids a decrease in discharge capacity maintenance rate due to a decrease in high-temperature storage characteristics or an increase in gas generation amount. It's easy to do.

  In the nonaqueous electrolytic solution of the present invention, the compound having at least two isocyanate groups in the molecule and the cyclic carbonate having a fluorine atom form a composite film on the negative electrode. From the viewpoint of satisfactorily forming such a film, the blending mass ratio of the compound having at least two isocyanate groups in the molecule and the fluorinated cyclic carbonate is preferably 0.4: 100 to 100: 100. : 100 to 50: 100 is more preferable, and 1.4: 100 to 35: 100 is still more preferable. When it mix | blends in this range, the side reaction in the positive / negative electrode of each additive can be suppressed efficiently, and a battery characteristic improves.

1-3-2. Cyclic carbonate having carbon-carbon unsaturated bond Cyclic carbonate having carbon-carbon unsaturated bond (hereinafter sometimes referred to as “unsaturated cyclic carbonate”) includes a carbon-carbon double bond or a carbon-carbon triple bond. Any cyclic carbonate having a bond is not particularly limited, and any unsaturated carbonate can be used. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.

  Examples of unsaturated cyclic carbonates include vinylene carbonates, aromatic carbonates, ethylene carbonates substituted with a substituent having a carbon-carbon double bond or carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, Catechol carbonates etc. are mentioned.

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-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate and the like. .

Specific examples of ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond include:
Vinylethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene 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 Examples include -5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, and the like.

Among them, particularly as an unsaturated cyclic carbonate preferable for use in combination with a compound having at least two isocyanate groups in the molecule,
Vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5 -Diethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate. Vinylene carbonate, vinyl ethylene carbonate, and ethynyl ethylene carbonate are particularly preferable because they form a more stable interface protective film.

The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 80 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. The molecular weight of the unsaturated cyclic carbonate is more preferably 85 or more, and more preferably 150 or less.
The production method of the unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method.

  An unsaturated cyclic carbonate may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the compounding quantity of unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The blending amount of the unsaturated cyclic carbonate is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more, in 100% by mass of the non-aqueous electrolyte solution. Moreover, Preferably it is 5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity maintenance ratio decreases. Easy to avoid.

1-3-3. Monofluorophosphate or difluorophosphate The counter cation of monofluorophosphate and difluorophosphate is not particularly limited, but lithium, sodium, potassium, magnesium, calcium, and NR ¹¹ R ¹² R Examples include ammonium represented by ¹³ R ¹⁴ (wherein R ^{11 to} R ¹⁴ each independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms).

Although there is no limitation in particular as a C1-C12 organic group represented by R < ¹¹ > -R < ¹⁴ > of the said ammonium, For example, it is substituted by the alkyl group, the halogen atom, or the alkyl group which may be substituted by the halogen atom. Examples thereof include an cycloalkyl group which may be 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, as R ^{11 to} R ¹⁴ , a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group is preferable.

Specific examples of monofluorophosphate and difluorophosphate include
Lithium monofluorophosphate, sodium monofluorophosphate, potassium monofluorophosphate, lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate and the like, lithium monofluorophosphate and lithium difluorophosphate are preferred, More preferred is lithium difluorophosphate.

Monofluorophosphate and difluorophosphate may be used singly or in combination of two or more in any combination and ratio. Moreover, the compounding quantity of a monofluoro phosphate and a difluoro phosphate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.
The blending amount of monofluorophosphate and difluorophosphate is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.1% in 100% by mass of the non-aqueous electrolyte. It is at least 5% by mass, preferably at most 5% by mass, more preferably at most 4% by mass, even more preferably at most 3% by mass.
Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity maintenance ratio decreases. Easy to avoid.

  The method of adding monofluorophosphate and difluorophosphate to the electrolytic solution is not particularly limited, but it is a method of adding monofluorophosphate and difluorophosphate synthesized by a known method directly to the electrolytic solution. Another method is to generate monofluorophosphate and difluorophosphate in the battery or in the electrolyte. Monofluorophosphate and difluorophosphate can be generated by adding compounds other than monofluorophosphate and difluorophosphate and oxidizing or hydrolyzing battery components such as electrolytes. The method of letting it be mentioned. Furthermore, a method of generating a battery by applying an electrical load such as charge / discharge is also mentioned.

  The content of monofluorophosphate and difluorophosphate in the nonaqueous electrolyte solution or nonaqueous electrolyte battery can be quantified by ion chromatography, F nuclear magnetic resonance spectroscopy, or the like.

  The weight ratio of the compound having at least two isocyanate groups in the molecule and the monofluorophosphate and difluorophosphate is usually 1: 500 to 300: 1, preferably 1:80 to 40: 1, more preferably 1. : 30 to 1.5: 1.

1-4. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.

For example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiTaF ₆ , LiWF _{7 and} other inorganic lithium salts; LiWOF _{5 and} other lithium tungstates; HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Lithium carboxylate such as Li; FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃ SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF Sulfonic acid lithium salts such as ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ Li; LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium imide salts such as lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) Lithium methide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ; lithium oxalatoborate such as lithium difluorooxalatoborate and lithium bis (oxalato) borate Salts: lithium tetrafluorooxalatophosphate, lithium difluorobis (oxala) G) Lithium oxalatophosphate salts such as phosphate and lithium tris (oxalato) phosphate; other, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) ₂ , And fluorine-containing organolithium salts such as LiBF ₂ (CF ₃ SO ₂ ) ₂ and LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ .

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , FSO ₃ Li, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF _{3 SO 2) 3, LiC (C} 2 F 5 SO 2) 3, lithium Bisuo Kisara oxalatoborate, lithium difluoro oxalatoborate, lithium tetrafluoro-oxa Lato phosphate, lithium difluoro bis oxa Lato _phosphate, LiBF ₃ CF _3, LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) _{3 and the} like are particularly preferable because they have an effect of improving output characteristics, high-rate charge / discharge characteristics, high-temperature storage characteristics, cycle characteristics, and the like.

These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using two or more types in combination is a combination of LiPF ₆ and LiBF ₄ or LiPF ₆ and FSO ₃ Li, which has an effect of improving load characteristics and cycle characteristics.
In this case, the concentration of LiBF ₄ or FSO ₃ Li with respect to 100% by mass of the entire non-aqueous electrolyte solution is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. For the non-aqueous electrolyte solution of the present invention, Usually, it is 0.01 mass% or more, Preferably it is 0.1 mass% or more, and is 30 mass% or less normally, Preferably it is 20 mass% or less.

Another example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has the effect of suppressing deterioration due to high-temperature storage. As an organic lithium salt, CF ₃ SO ₃
Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethane Disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, Lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ Etc. are preferred. In this case, the concentration of the organic lithium salt with respect to 100% by mass of the entire non-aqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and preferably 30% by mass or less. Especially preferably, it is 20 mass% or less.

The concentration of these lithium salts in the non-aqueous electrolyte solution is not particularly limited as long as the effects of the present invention are not impaired. The total molar concentration of lithium in the aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, still more preferably 0.5 mol / L or more, and preferably 3 mol / L. Hereinafter, it is more preferably 2.5 mol / L or less, and further preferably 2.0 mol / L or less.
If the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity, resulting in decreased battery performance. There is a case.

1-5. Nonaqueous solvent There is no restriction | limiting in particular about the nonaqueous solvent in this invention, It is possible to use a well-known organic solvent. Examples thereof include cyclic carbonates having no fluorine atom, chain carbonates, cyclic and chain carboxylic acid esters, ether compounds, sulfone compounds, and the like.

<Cyclic carbonate not having fluorine atoms>
Examples of the cyclic carbonate having no fluorine atom include cyclic carbonates having an alkylene group having 2 to 4 carbon atoms.
Specific examples of the cyclic carbonate having an alkylene group having 2 to 4 carbon atoms and having no fluorine atom include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

  The cyclic carbonate which does not have a fluorine atom may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  The blending amount of the cyclic carbonate not having a fluorine atom is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. However, the blending amount when one kind is used alone is 100 volumes of a non-aqueous solvent. %, Usually 5% by volume or more, more preferably 10% by volume or more. By setting this range, the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the high current discharge characteristics, stability against the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery are in a good range. And it will be easier. Moreover, it is 95 volume% or less normally, Preferably it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the load characteristics of the non-aqueous electrolyte battery are easily set in a favorable range.

<Chain carbonate>
As the chain carbonate, a chain carbonate having 3 to 7 carbon atoms is preferable.
More preferred is 7 dialkyl carbonate.
Specific examples of the chain carbonate 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, isobutyl methyl. Examples include carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate, and the like.

  Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable. is there.

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

  Fluorinated dimethyl carbonate and derivatives thereof include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like. It is done.

  Fluorinated ethyl methyl carbonate and derivatives thereof include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2 -Trifluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, ethyl trifluoromethyl carbonate, etc. are mentioned.

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

  A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set in an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte battery are easily set in a favorable range. Also,
The chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the nonaqueous solvent. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity resulting from a decrease in dielectric constant of the nonaqueous electrolyte solution, and to make the large current discharge characteristics of the nonaqueous electrolyte solution battery in a favorable range.

<Cyclic carboxylic acid ester>
The cyclic carboxylic acid ester is preferably one having 3 to 12 carbon atoms.
Specific examples include gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone, and the like. Among these, gamma butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

A cyclic carboxylic acid ester may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. If it is this range, it will become easy to improve the electrical conductivity of a non-aqueous electrolyte solution, and to improve the large current discharge characteristic of a non-aqueous electrolyte battery. Moreover, the compounding quantity of cyclic carboxylic acid ester becomes like this. Preferably it is 50 volume% or less, More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

<Chain carboxylic acid ester>
The chain carboxylic acid ester is preferably one having 3 to 7 carbon atoms. In particular,
Methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, propion Acid-n-butyl, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, butyric acid n-propyl, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid n-propyl, isopropyl isobutyrate Etc.

  Among them, methyl acetate, ethyl acetate, acetate-n-propyl acetate-n-butyl acetate, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoint of improvement of ionic conductivity.

A chain carboxylic acid ester may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The compounding amount of the chain carboxylic acid ester is usually 10% by volume or more, more preferably 15% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte battery are easily improved. Moreover, the compounding quantity of chain | strand-shaped carboxylic acid ester is 60 volume% or less preferably in 100 volume% of nonaqueous solvents, More preferably, it is 50 volume% or less. By setting the upper limit in this way, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte battery are easily set in a favorable range.

<Ether compound>
As the ether compound, a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms in which part of hydrogen may be substituted with fluorine is preferable.

As the chain ether having 3 to 10 carbon atoms,
Diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2, 2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2-trifluoroethyl) ether, (2-fluoroethyl) ) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, ethyl-n-propyl ether, ethyl (3-Fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) ether, ethyl (2,2,3,3-teto Fluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propylether, (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-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 (Ro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3,3-tetrafluoro-n-propyl) Ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, (3-fluoro-n-propyl) (3 , 3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) ether ) (2, 2, 3, 3- Trifluoro-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, methoxyethoxymethane, methoxy (2-fluoroethoxy) methane, methoxy (2,2,2-tri Fluoroethoxy) methanemethoxy (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-trifluoroethoxy) Methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2,2-trifluoroethoxy) (1,1 , 2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ethane, methoxy (2,2,2 -Trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy Ci (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2-fluoroethoxy) ethane, (2 -Fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2,2,2-trifluoroethoxy) Ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) ethane, ethylene glycol di-n- Examples include propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

  Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.

  Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.

An ether type compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The compounding amount of the ether compound is usually in 100% by volume of the non-aqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less.
If it is this range, it is easy to ensure the improvement effect of the lithium ion dissociation degree of chain ether, and the improvement of the ionic conductivity derived from a viscosity fall, and when a negative electrode active material is a carbonaceous material, a chain ether with lithium ion It is easy to avoid a situation where the capacity is reduced due to co-insertion.

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

As cyclic sulfone having 3 to 6 carbon atoms,
Examples include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds.
Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

  As the sulfolanes, sulfolane and / or sulfolane derivatives (hereinafter sometimes referred to as “sulfolanes” including sulfolane) are preferable. As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are 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 Methyl sulfolane, 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 preferable in terms of high ionic conductivity and high input / output characteristics.

In addition, as the chain sulfone having 2 to 6 carbon atoms,
Dimethylsulfone, ethylmethylsulfone, diethylsulfone, n-propylmethylsulfone, n-propylethylsulfone, di-n-propylsulfone, isopropylmethylsulfone, isopropylethylsulfone, diisopropylsulfone, n-butylmethylsulfone, n-butylethyl Sulfone, t-butylmethylsulfone, t-butylethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, monofluoroethylmethylsulfone, difluoroethylmethylsulfone, trifluoroethylmethylsulfone, pentafluoro Ethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, perf Oroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di (trifluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n-propyl sulfone, trifluoromethyl- n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, pentafluoroethylisopropylsulfone , Trifluoroethyl-n-butylsulfone, trifluoroethyl-t-butylsulfone, pentafluoroethyl- - butyl sulfone, pentafluoroethyl -t- butyl sulfone, and the like.

  Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is high ion conductivity, preferable because the input-output characteristic is high.

A sulfone compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The compounding amount of the sulfone compound is usually 0.3% by volume or more, more preferably 1% by volume or more, still more preferably 5% by volume or more in 100% by volume of the non-aqueous solvent, and preferably 40%. Volume% or less, More preferably, it is 35 volume% or less, More preferably, it is 30 volume% or less.
Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.

<Composition of non-aqueous solvent when cyclic carbonate having fluorine atom is not used or used as auxiliary agent>
In the present invention, when the cyclic carbonate having a fluorine atom is not used or used as an auxiliary agent, the above-exemplified nonaqueous solvent alone may be used as the nonaqueous solvent other than the cyclic carbonate having a fluorine atom. In addition, two or more kinds may be used in any combination and ratio.

For example, one preferred combination of non-aqueous solvents is a combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate.
Among them, the total of cyclic carbonate and chain carbonate having no fluorine atom in the non-aqueous solvent is preferably 70% by volume or more, more preferably 80% by volume or more, and still more preferably 90% by volume or more, The ratio of the cyclic carbonate having no fluorine atom to the total of the cyclic carbonate and the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more. Preferably it is 50 volume% or less, More preferably, it is 35 volume% or less, More preferably, it is 30 volume% or less, Most preferably, it is 25 volume% or less.
When a combination of these non-aqueous solvents is used, the balance between the cycle characteristics and high-temperature storage characteristics (particularly, the remaining capacity and high-load discharge capacity after high-temperature storage) of a battery produced using the non-aqueous solvent may be improved.

For example, as a specific example of a preferable combination of a cyclic carbonate having no fluorine atom and a chain carbonate,
Ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate and diethyl carbonate and ethyl methyl carbonate, ethylene carbonate And dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

Among the combinations of cyclic carbonates and chain carbonates not having a fluorine atom, those containing asymmetric chain alkyl carbonates as chain carbonates are more preferable, in particular, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, Those containing ethylene carbonate, symmetric chain carbonates and asymmetric chain carbonates such as ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate have cycle characteristics and large current discharge characteristics. This is preferable because of a good balance.
Among them, the asymmetric chain carbonate is preferably ethyl methyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

A combination in which propylene carbonate is further added to the combination of these ethylene carbonates and chain carbonates is also a preferable combination.
In the case of containing propylene carbonate, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 40:60, particularly preferably 95: 5 to 50:50. Further, the proportion of propylene carbonate in the whole non-aqueous solvent is preferably 0.1% by volume or more, more preferably 1% by volume or more, further preferably 2% by volume or more, and preferably 20% by volume or less, more preferably Is 8% by volume or less, more preferably 5% by volume or less.
It is preferable to contain propylene carbonate in this concentration range because the low temperature characteristics may be further improved while maintaining the combination characteristics of ethylene carbonate and chain carbonate.

When dimethyl carbonate is contained in the non-aqueous solvent, the proportion of dimethyl carbonate in the total non-aqueous solvent is preferably 10% by volume or more, more preferably 20% by volume or more, and even more preferably 25% by volume or more. Preferably it is 30% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less, further preferably 75% by volume or less, and particularly preferably 70% by volume or less. The load characteristics of the battery may be improved.
Above all, it contains dimethyl carbonate and ethyl methyl carbonate, and by increasing the content ratio of dimethyl carbonate over the content ratio of ethyl methyl carbonate, the electrical conductivity of the electrolyte can be maintained, but the battery characteristics after high-temperature storage are improved. This is preferable.

The volume ratio of dimethyl carbonate to ethyl methyl carbonate in all non-aqueous solvents (dimethyl carbonate / ethyl methyl carbonate) is 1.1 or more in terms of improving the electric conductivity of the electrolyte and improving the battery characteristics after storage. Is preferable, 1.5 or more is more preferable, and 2.5 or more is more preferable. The volume ratio (dimethyl carbonate / ethyl methyl carbonate) is preferably 40 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 8 or less, from the viewpoint of improving battery characteristics at low temperatures.
In the combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate, a cyclic carboxylic acid ester, a chain carboxylic acid ester, a cyclic ether, a chain ether, a sulfur-containing organic solvent, You may mix other solvents, such as a phosphorus organic solvent and an aromatic fluorine-containing solvent.
In this specification, the volume of the non-aqueous solvent is a measured value at 25 ° C., but the measured value at the melting point is used for a solid at 25 ° C. such as ethylene carbonate.

<Composition of non-aqueous solvent when cyclic carbonate having fluorine atom is used as non-aqueous solvent>
In the present invention, when a cyclic carbonate having a fluorine atom is used as a non-aqueous solvent, as the non-aqueous solvent other than the cyclic carbonate having a fluorine atom, one of the non-aqueous solvents exemplified above is used as a cyclic carbonate having a fluorine atom. They may be used in combination, or two or more may be used in combination with a cyclic carbonate having a fluorine atom.

For example, one preferred combination of non-aqueous solvents is a combination mainly composed of a cyclic carbonate having a fluorine atom and a chain carbonate. Among them, the total of the cyclic carbonate having a fluorine atom and the chain carbonate in the non-aqueous solvent is preferably 60% by volume or more, more preferably 80% by volume or more, and further preferably 90% by volume or more, and the fluorine atom. The ratio of the cyclic carbonate having a fluorine atom to the total of the cyclic carbonate having a chain and the chain carbonate is 3% by volume or more, preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more. Further, it is preferably 60% by volume or less, more preferably 50% by volume or less, still more preferably 40% by volume or less, and particularly preferably 35% by volume or less.
When a combination of these non-aqueous solvents is used, the balance between the cycle characteristics and high-temperature storage characteristics (particularly, the remaining capacity and high-load discharge capacity after high-temperature storage) of a battery produced using the non-aqueous solvent may be improved.

For example, as a specific example of a preferable combination of a cyclic carbonate having a fluorine atom and a chain carbonate,
Monofluoroethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and diethyl carbonate, monofluoroethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, monofluoro Examples thereof include ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

  Among the combinations of cyclic carbonates having a fluorine atom and chain carbonates, those containing symmetric chain alkyl carbonates as chain carbonates are more preferable, and in particular, monofluoroethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, Cycle characteristics include monofluoroethylene carbonate, symmetric chain carbonates and asymmetric chain carbonates such as fluoroethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate. And a large current discharge characteristic are preferable. Among these, the symmetric chain carbonate is preferably dimethyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

A combination in which a cyclic carbonate not having a fluorine atom is further added to the combination of the cyclic carbonate having a fluorine atom and the chain carbonate is also a preferable combination. Among them, the total of the cyclic carbonate having a fluorine atom and the cyclic carbonate having no fluorine atom in the non-aqueous solvent is preferably 10% by volume or more, more preferably 15% by volume or more, and further preferably 20% by volume or more. The ratio of the cyclic carbonate having a fluorine atom to the total of the cyclic carbonate having a fluorine atom and the cyclic carbonate having no fluorine atom is 5% by volume or more, preferably 10% by volume or more, more preferably 15% by volume. % Or more, more preferably 25% by volume or more, preferably 95% by volume or less, more preferably 85% by volume or less, still more preferably 75% by volume or less, and particularly preferably 60% by volume or less.
When a cyclic carbonate having no fluorine atom is contained in this concentration range, the electrical conductivity of the electrolytic solution can be maintained while forming a stable protective film on the negative electrode.

As a specific example of a preferable combination of a cyclic carbonate having a fluorine atom and a cyclic carbonate having no fluorine atom and a chain carbonate,
Monofluoroethylene carbonate and ethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and ethylene carbonate and diethyl carbonate, monofluoroethylene carbonate and ethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoro Ethylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, diethyl carbonate, and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate Monofluoroethylene carbonate and propylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and propylene carbonate and diethyl carbonate, monofluoroethylene carbonate and propylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate, dimethyl carbonate and diethyl carbonate, Monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate Tylmethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, monofluoroethylene Carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate and propylene carbonate Examples include diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

Among the combinations of a cyclic carbonate having a fluorine atom and a cyclic carbonate having no fluorine atom and a chain carbonate, those containing a symmetric chain alkyl carbonate as the chain carbonate are more preferred,
Monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoro Ethylene carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate Nate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, and dimethyl carbonate It is preferable to use monofluoroethylene carbonate, symmetric chain carbonates, and asymmetric chain carbonates such as sodium carbonate, diethyl carbonate, and ethyl methyl carbonate because the balance between cycle characteristics and large current discharge characteristics is good. Among them, the symmetric chain carbonate is preferably dimethyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

  When dimethyl carbonate is contained in the non-aqueous solvent, the proportion of dimethyl carbonate in the total non-aqueous solvent is preferably 10% by volume or more, more preferably 20% by volume or more, and even more preferably 25% by volume or more. Preferably, the content is 30% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less, still more preferably 75% by volume or less, and particularly preferably 70% by volume or less. The load characteristics may be improved.

  Above all, it contains dimethyl carbonate and ethyl methyl carbonate, and by increasing the content ratio of dimethyl carbonate over the content ratio of ethyl methyl carbonate, the electric conductivity of the electrolyte can be maintained, but the battery characteristics after high temperature storage are improved. Therefore, it is preferable.

The volume ratio of dimethyl carbonate to ethyl methyl carbonate in all non-aqueous solvents (dimethyl carbonate / ethyl methyl carbonate) is 1.1 or more in terms of improving the electric conductivity of the electrolyte and improving the battery characteristics after storage. Is preferable, 1.5 or more is more preferable, and 2.5 or more is more preferable.
The volume ratio (dimethyl carbonate / ethyl methyl carbonate) is preferably 40 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 8 or less, from the viewpoint of improving battery characteristics at low temperatures.

  In the combination mainly composed of the cyclic carbonate having a fluorine atom and the chain carbonate, in addition to the cyclic carbonate having no fluorine atom, a cyclic carboxylic acid ester, a chain carboxylic acid ester, a cyclic ether, Other solvents such as chain ethers, sulfur-containing organic solvents, phosphorus-containing organic solvents, and fluorine-containing aromatic solvents may be mixed.

1-6. Auxiliary Agent In the non-aqueous electrolyte battery of the present invention, an auxiliary agent may be appropriately used according to the purpose other than the compounds described in 1-1 to 1-5. Examples of the auxiliary agent include monoisocyanates, cyclic sulfonate esters, nitrile compounds, compounds represented by formulas (2) to (6), overcharge inhibitors, and other auxiliary agents.

<Monoisocyanate>
The monoisocyanate compound is not particularly limited as long as it is a compound having one isocyanate group in the molecule.
Specific examples of the monoisocyanate compound include, for example,
Examples include methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, tertiary butyl isocyanate, pentyl isocyanate hexyl isocyanate, cyclohexyl isocyanate, vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, propynyl isocyanate, phenyl isocyanate, and fluorophenyl isocyanate. .

  Of these, methyl isocyanate, ethyl isocyanate, allyl isocyanate, and propynyl isocyanate are preferred from the viewpoint of improving battery characteristics.

Furthermore, a monoisocyanate compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no limit to the amount of the monoisocyanate compound added to the whole non-aqueous electrolyte solution of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired, but usually 0.001 mass relative to the non-aqueous electrolyte solution of the present invention. %, Preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less.
When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved.

<Cyclic sulfonate ester>
The cyclic sulfonic acid ester is not particularly limited as long as it is a sulfonic acid ester having a cyclic structure.
Specific examples of the cyclic sulfonate ester 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-butane sultone, 1-fluoro-1,4-butane sultone, 2-fluoro-1,4-butane sultone, 3-fluoro-1,4-butane sultone, 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-pentanthruton 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-pe Tan sultone, 5-methyl-1,5-pentanthrutone, 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-pente -1,5-sultone, 2-fluoro-3-pentene-1,5-sultone, 3-fluoro-3-pentene-1,5-sultone, 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, 4-methyl-4-pentene-1,5-sultone, 5-methyl-4-pentene- Sultone compounds such as 1,5-sultone

  Sulfate compounds such as methylene sulfate, ethylene sulfate, propylene sulfate; disulfonate compounds such as methylene methane disulfonate and ethylene methane disulfonate; 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-oxathiazol-2,2-dioxide, 5H-1,2,4-oxathiazole-2,2-dioxide, 1,2,5-oxathiazolidine- , 2-dioxide, 5-methyl-1,2,5-oxathiazolidine-2,2-dioxide, 3H-1,2,5-oxathiazole-2,2-dioxide, 5H-1,2,5-oxa Thiazole-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, Nitrogen-containing compounds such as 4-dihydro-1,2,6-oxathiazine-2,2-dioxide, 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide;

  1,2,3-oxathiaphoslane-2,2-dioxide, 3-methyl-1,2,3-oxathiaphoslane-2,2-dioxide, 3-methyl-1,2,3-oxathi Aphoslane-2,2,3-trioxide, 3-methoxy-1,2,3-oxathiaphoslane-2,2,3-trioxide, 1,2,4-oxathiaphoslane-2,2-dioxide 4-methyl-1,2,4-oxathiaphoslane-2,2-dioxide, 4-methyl-1,2,4-oxathiaphoslane-2,2,4-trioxide, 4-methoxy-1 , 2,4-Oxathiaphoslane-2,2,4-trioxide, 1,2,5-oxathiaphoslane-2,2-dioxide, 5-methyl-1,2,5-oxathiaphoslane- 2,2-dioxide, 5-methyl-1,2,5-oxathia Suranium-2,2,5-trioxide, 5-methoxy-1,2,5-oxathiaphoslane-2,2,5-trioxide, 1,2,3-oxathiaphosphinan-2,2-dioxide, 3-methyl-1,2,3-oxathiaphosphinan-2,2-dioxide, 3-methyl-1,2,3-oxathiaphosphinan-2,2,3-trioxide, 3-methoxy-1, 2,3-oxathiaphosphinan-2,2,3-trioxide, 1,2,4-oxathiaphosphinan-2,2-dioxide, 4-methyl-1,2,4-oxathiaphosphinan-2 , 2-dioxide, 4-methyl-1,2,4-oxathiaphosphinan-2,2,3-trioxide, 4-methyl-1,5,2,4-dioxathiaphosphinan-2,4- Dioxide, 4-methoxy 1,5,2,4-dioxathiaphosphinan-2,4-dioxide, 3-methoxy-1,2,4-oxathiaphosphinan-2,2,3-trioxide, 1,2,5-oxa Thiaphosphinan-2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphinan-2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphinan-2,2, 3-trioxide, 5-methoxy-1,2,5-oxathiaphosphinan-2,2,3-trioxide, 1,2,6-oxathiaphosphinan-2,2-dioxide, 6-methyl-1, 2,6-oxathiaphosphinan-2,2-dioxide, 6-methyl-1,2,6-oxathiaphosphinan-2,2,3-trioxide, 6-methoxy-1,2,6-oxathia Phosphinan-2,2 And phosphorus-containing compounds such as 3-trioxide;

Of 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, methylenemethane Disulfonate and ethylenemethane disulfonate are preferable from the viewpoint of improving storage characteristics, and 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1 , 3-propane sultone and 1-propene-1,3-sultone are more preferable.

  A cyclic sulfonic acid ester may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. There is no limitation on the amount of the cyclic sulfonate ester added to the entire non-aqueous electrolyte of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired. It is contained at a concentration of not less than mass%, preferably not less than 0.1 mass%, more preferably not less than 0.3 mass%, and usually not more than 10 mass%, preferably not more than 5 mass%, more preferably not more than 3 mass%. . When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved.

<Nitrile compound>
The type of nitrile compound is not particularly limited as long as it is a compound having a nitrile group in the molecule.
Specific examples of nitrile compounds include, for example,
Acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile , Crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitryl, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile, 2-hexenenitrile, Fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile, 2,3-diph Oropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3,3′-oxydipropionitrile, 3,3 ′ A compound having one nitrile group such as thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, pentafluoropropionitrile;

Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononitrile, methylsuccinonitrile 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, 2,3,3-trimethylsuccinonitrile, 2,2,3,3-tetramethylsuccinonitrile, 2,3-diethyl- 2,
3-dimethylsuccinonitrile, 2,2-diethyl-3,3-dimethylsuccinonitrile, bicyclohexyl-1,1-dicarbonitrile, bicyclohexyl-2,2-dicarbonitrile, bicyclohexyl-3,3 -Dicarbonitrile, 2,5-dimethyl-2,5-hexanedicarbonitrile, 2,3-diisobutyl-2,3-dimethylsuccinonitrile, 2,2-diisobutyl-3,3-dimethylsuccinonitrile, 2-methylglutaronitrile, 2,3-dimethylglutaronitrile, 2,4-dimethylglutaronitrile, 2,2,3,3-tetramethylglutaronitrile, 2,2,4,4-tetramethylglu Talonitrile, 2,2,3,4-tetramethylglutaronitrile, 2,3,3,4-tetramethylglutaronitrile, maleoni Ril, fumaronitrile, 1,4-dicyanopentane, 2,6-dicyanoheptane, 2,7-dicyanooctane, 2,8-dicyanononane, 1,6-dicyanodecane, 1,2-didiananobenzene, 1,3- Compounds having two nitrile groups such as dicyanobenzene, 1,4-dicyanobenzene, 3,3 ′-(ethylenedioxy) dipropionitrile, 3,3 ′-(ethylenedithio) dipropionitrile;

Compounds having three cyano groups such as cyclohexanetricarbonitrile, triscyanoethylamine, triscyanoethoxypropane, tricyanoethylene, pentanetricarbonitrile, propanetricarbonitrile, heptanetricarbonitrile;
Etc.

  Of these, lauronitrile, crotononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, and fumaronitrile are preferable from the viewpoint of improving storage characteristics. Further, dinitrile compounds such as succinonitrile, glutaronitrile, adiponitrile, pimonitrile, suberonitrile, azeronitrile, sebacononitrile, undecanedinitrile, dodecanedilonitrile, and fumaronitrile are particularly preferable.

  A nitrile compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. There is no limitation on the amount of the nitrile compound added to the whole non-aqueous electrolyte of the present invention, and it is optional as long as the effect of the present invention is not significantly impaired. Above, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved.

式（２）中、Ｍ^１は周期表における１族、２族及びアルミニウム（Ａｌ）から選択される元素であり、Ｍ^２は遷移金属、周期表の１３族、１４族、及び１５族から選択される元素であり、Ｒはハロゲン、炭素数１〜１１のアルキル基、及び炭素数１〜１１のハロゲン置換アルキル基から選択される基であり、ａ及びｂは正の整数であり、ｃは０または正の整数であり、ｄは１〜３の整数である。）
式（２）で示される化合物はオキサラト錯体をアニオンとする塩である。式中、Ｍ^１はリチウム二次電池に用いたときの電池特性の点から、リチウム、ナトリウム、カリウム、マグネシウム、カルシウムが好ましく、リチウムが特に好ましい。また、Ｍ^２はリチウム二次電池に用いる場合の電気化学的安定性の点で、ホウ素及びリンが特に好ましい。Ｒとして具体的には、フッ素、塩素、メチル基、トリフルオロメチル基、エチル基、ペンタフルオロエチル基、プロピル基、イソプロピル基、ブチル基、ｓｅｃ−ブチル基、ｔ−ブチ
ル基、等が例示できる。この中では特にフッ素、トリフルオロメチル基が好ましい。 <Compound represented by Formula (2)>

In Formula (2), M ¹ is an element selected from Group 1, Group 2 and Aluminum (Al) in the Periodic Table, and M ² is selected from Transition Metal, Group 13, Group 14, and Group 15 of the Periodic Table R is a group selected from halogen, an alkyl group having 1 to 11 carbon atoms, and a halogen-substituted alkyl group having 1 to 11 carbon atoms, a and b are positive integers, and c is It is 0 or a positive integer, d is an integer of 1-3. )
The compound represented by the formula (2) is a salt having an oxalato complex as an anion. In the formula, M ¹ is preferably lithium, sodium, potassium, magnesium or calcium, particularly preferably lithium, from the viewpoint of battery characteristics when used in a lithium secondary battery. M ² is particularly preferably boron or phosphorus from the viewpoint of electrochemical stability when used in a lithium secondary battery. Specific examples of R include fluorine, chlorine, methyl group, trifluoromethyl group, ethyl group, pentafluoroethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, and t-butyl group. . Of these, fluorine and trifluoromethyl groups are particularly preferred.

  The content of the compound represented by the formula (2) in the nonaqueous electrolytic solution is 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and usually 1. It is 5% by mass or less, preferably 1.3% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less. If this concentration is too low, the chemical and physical stability of the film may be insufficient. If the concentration is too high, the insulating properties of the film may increase, and the discharge capacity may decrease due to increased resistance. When the content of the compound represented by the formula (2) is within the above range, a synergistic effect with the compound having at least two isocyanate groups in the molecule can be easily obtained, and the reductive decomposition reaction of the nonaqueous solvent that occurs at the time of charging can be further improved. Therefore, the battery life can be improved such as high-temperature storage characteristics and cycle characteristics, the charge / discharge efficiency of the battery can be improved, and the low-temperature characteristics can be improved.

  The method of incorporating the compound represented by the formula (2) into the electrolytic solution is not particularly limited, but in addition to the method of directly adding the compound represented by the formula (2) synthesized by a known technique to the electrolytic solution, the battery A method of generating the compound represented by the formula (2) in the inside or in the electrolytic solution is mentioned. Examples of the method for generating the compound represented by the formula (2) include a method in which a compound other than the compound represented by the formula (2) is added to generate a battery component such as an electrolytic solution by oxidation or hydrolysis. It is done. Furthermore, a method of generating a battery by applying an electrical load such as charge / discharge is also mentioned.

  The content of the compound represented by the formula (2) in the non-aqueous electrolyte solution or the non-aqueous electrolyte battery can be quantified by ion chromatography, F nuclear magnetic resonance spectroscopy, or the like.

  The mass ratio of the compound having at least two isocyanate groups in the molecule and the compound represented by the formula (2) is usually 1: 500 to 300: 1, preferably 1:80 to 40: 1, more preferably 1:30. In the range of ~ 1.5: 1.

<Compounds represented by formulas (3) to (5)>
The compounds represented by the formulas (3) to (5) may be included singly or in combination of two or more in the nonaqueous electrolytic solution of the present invention. The content of the compounds represented by the formulas (3) to (5) in the non-aqueous electrolyte solution (in the case of two or more types) is 0.01% by mass or more, preferably 0.05% by mass or more, More preferably, it is 0.1 mass% or more, Usually, 5 mass% or less, Preferably it is 4 mass% or less, More preferably, it is the range of 3 mass% or less. If this concentration is too low, the chemical and physical stability of the film may be insufficient. If the concentration is too high, the insulating properties of the film may increase, and the discharge capacity may decrease due to increased resistance. When the content of the compounds represented by the formulas (3) to (5) is in the above range, a synergistic effect with the compound having at least two isocyanate groups in the molecule is easily obtained, and the reduction of the nonaqueous solvent that occurs during charging The decomposition reaction can be suppressed to a lower level, and the battery life such as high-temperature storage characteristics and cycle characteristics can be improved, the charge / discharge efficiency of the battery can be improved, and the low-temperature characteristics can be improved.

  The method of blending the compounds represented by the formulas (3) to (5) in the electrolytic solution is not particularly limited, but the compounds represented by the formulas (3) to (5) synthesized by a known method are directly used as the electrolytic solution. In addition to the method of adding, there is a method of generating the compounds represented by the formulas (3) to (5) in the battery or in the electrolytic solution. As a method for generating the compounds represented by the formulas (3) to (5), a compound other than the compounds represented by the formulas (3) to (5) is added to oxidize or hydrolyze battery components such as an electrolytic solution. And the like. Furthermore, a method of generating a battery by applying an electrical load such as charge / discharge is also mentioned.

式（３）中のｌおよびｍは、０〜４の整数であり、同じ値でもよいし、異なっていてもよい。通常、こうした塩のアニオンのサイズが大きすぎると、イオン移動度が低下したり、皮膜抵抗が増大したりすることがある。 [Compound represented by Formula (3)]

L and m in the formula (3) are integers of 0 to 4, and may be the same value or different. Usually, when the size of the anion of such a salt is too large, the ion mobility may decrease or the film resistance may increase.

式（４）で表される化合物も同等の効果があって、やはり上述の式（３）で示される化合物の説明と同じ理由により、ｎの値は０〜４の整数である。 [Compound represented by Formula (4)]

The compound represented by the formula (4) has the same effect, and the value of n is an integer of 0 to 4 for the same reason as described for the compound represented by the formula (3).

式（５）中、Ｍ^３は金属原子、リン原子、ホウ素原子、またはＰ＝Ｏを表す。Ｒ^１は炭素数１〜１１のアルキルオキシ基、シリルオキシ基、または炭素数１〜１１のアルキルシリルオキシ基を表す。ｅはＭ^３に結合するＲ¹の個数を表す。ｅが２以上の場合、Ｒ^３は同一でも異なってもよい。Ｒ^４〜Ｒ^６はそれぞれ独立に炭素数１〜１１のアルキル基、炭素数１〜１１のアルケニル基、炭素数１〜１１のアルキルオキシ基、または炭素数６〜１１のアリール基を表す。 [Compound represented by Formula (5)]

In formula (5), M ³ represents a metal atom, a phosphorus atom, a boron atom, or P═O. R ¹ represents an alkyloxy group having 1 to 11 carbon atoms, a silyloxy group, or an alkylsilyloxy group having 1 to 11 carbon atoms. e represents the number of R ¹ bonded to M ³ . When e is 2 or more, R ³ may be the same or different. R ^{4 to} R ⁶ each independently represents an alkyl group having 1 to 11 carbon atoms, an alkenyl group having 1 to 11 carbon atoms, an alkyloxy group having 1 to 11 carbon atoms, or an aryl group having 6 to 11 carbon atoms.

  Specific examples of the compound represented by the formula (5) include the compounds shown below. Magnesium bis (trimethylsiloxide), tris borate (trimethylsilyl), tris borate (trimethoxysilyl), tris borate (triethylsilyl), tris borate (triethoxysilyl), tris borate (dimethylvinylsilyl) ), Tris (diethylvinylsilyl) borate, aluminum tris (trimethylsiloxide), dimethoxyaluminoxytrimethylsilane, dimethoxyaluminoxytrimethoxysilane, diethoxyaluminoxytrimethoxysilane, diethoxyaluminoxytriethoxysilane, dipropyloxy Aluminoxytrimethylsilane, dibutoxyaluminoxytrimethylsilane, dibutoxyaluminoxytrimethoxysilane, dibutoxyaluminoxytriethylsilane, dibutoxyaluminoxyt Ethoxysilane, dipropoxyaluminoxytriethoxysilane, dibutoxyaluminoxytripropylsilane, dibutoxyaluminoxytrimethoxysilane, dibutoxyaluminoxytriethoxysilane, dibutoxyaluminoxytripropyoxysilane, dibutoxyaluminoxytriphenoxy Sisilane, tris phosphate (trimethylsilyl), tris phosphate (triethylsilyl), tris phosphate (tripropylsilyl), tris phosphate (triphenylsilyl), tris phosphate (trimethoxysilyl), tris phosphate (tri Ethoxysilyl), tris phosphate (triphenoxysilyl), tris phosphate (dimethylvinylsilyl), tris phosphate (diethylvinylsilyl), scandium tris (trimethylsiloxide), titanium tetrakis Methylsiloxide), titanium tetrakis (triethylsiloxide), titanium tetrakis (trimethoxysiloxide), titaniumoxybis (trimethylsiloxide), vanadiumoxytris (trimethylsiloxide), zinc bis (trimethylsiloxide), germanium tetrakis (Trimethylsiloxide), tin tetrakis (trimethylsiloxide), yttrium tris (trimethylsiloxide), zirconium tetrakis (trimethylsiloxide), niobium pentakis (trimethylsiloxide) and the like.

<Compound represented by formula (6)>

等が挙げられ、中でも更に沸点などの観点から好ましくは、

等が挙げられる。 In formula (6), X ^{1 to} X ⁶ each independently represent a halogen atom, an alkyl group, an aryl group, an alkoxy group or an aryloxy group, and may be the same or different.
As the compound represented by the formula (6), specifically,

Among them, preferably from the viewpoint of boiling point,

Etc.

が挙げられる。 Furthermore, from the viewpoint that there are few side reactions in the battery and it is difficult to inhibit the battery reaction,

Is mentioned.

The compound represented by Formula (6) may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
There is no limitation on the amount of the compound represented by the formula (6) with respect to the whole non-aqueous electrolyte of the present invention, and it is optional as long as the effect of the present invention is not significantly impaired. 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, most preferably 1.0% by mass or more, and preferably 5% by mass or less, more Preferably it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted.

<Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively prevent the battery from bursting or igniting when the non-aqueous electrolyte battery is overcharged.

As an overcharge prevention agent,
Aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenylether, dibenzofuran; 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p -Partially fluorinated products of the above aromatic compounds such as cyclohexylfluorobenzene; fluorine-containing anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole, etc. Can be mentioned. Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable.

  These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, Using at least one selected from aromatic compounds not containing oxygen, such as t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether, dibenzofuran, and the like is an overcharge prevention property and a high temperature storage property. From the standpoint of balance.

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

<Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. As other auxiliaries,
Carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, diglycolic anhydride Carboxylic acid anhydrides such as cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9- Spiro compounds such as divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, diphenylsulfone, N , N-dimethylmethane Lufonamide, N, N-diethylmethanesulfonamide, methyl vinylsulfonate, ethyl vinylsulfonate, allyl vinylsulfonate, methyl allylsulfonate, ethyl allylsulfonate, allylsulfonate, 1,2-bis (vinylsulfonate Sulfur-containing compounds such as loxy) ethane; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, N-methylsuccinimide, etc. Nitrogen compounds of: trimethyl phosphite, triethyl phosphite, triphenyl phosphite, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dimethyl methylphosphonate, diethyl ethylphosphonate, dimethyl vinylphosphonate, vinylphosphone Diethyl acid, diethylfo Phosphorus compounds such as ethyl phonacetate, methyl dimethylphosphinate, ethyl diethylphosphinate, trimethylphosphine oxide, triethylphosphine oxide; hydrocarbon compounds such as heptane, octane, nonane, decane, cycloheptane; fluorobenzene, difluorobenzene, hexa Fluorine-containing aromatic compounds such as fluorobenzene and benzotrifluoride; These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

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

As mentioned above, what exists in the inside of the non-aqueous electrolyte battery as described in this invention is also contained in the above-mentioned non-aqueous electrolyte.
Specifically, the components of the non-aqueous electrolyte solution such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte solution is prepared from what is substantially isolated by the method described below. In the case of a nonaqueous electrolyte solution in a nonaqueous electrolyte battery obtained by pouring into a separately assembled battery, the components of the nonaqueous electrolyte solution of the present invention are individually placed in the battery, In order to obtain the same composition as the non-aqueous electrolyte solution of the present invention by mixing in a non-aqueous electrolyte battery, the compound constituting the non-aqueous electrolyte solution of the present invention is further generated in the non-aqueous electrolyte battery. The case where the same composition as the aqueous electrolyte is obtained is also included.

2. Battery Configuration The non-aqueous electrolyte battery of the present invention is suitable for use as an electrolyte for a secondary battery, for example, a lithium secondary battery, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention will be described.
The non-aqueous electrolyte battery of the present invention can adopt a known structure. Typically, the negative electrode and the positive electrode capable of occluding and releasing ions (for example, lithium ions), and the non-aqueous electrolysis of the present invention described above. Liquid.

2-1. Negative electrode The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. Specific examples include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like. These may be used individually by 1 type, and may be used together combining 2 or more types arbitrarily. The fourth aspect of the present invention is characterized in that the negative electrode contains a carbonaceous material.

<Negative electrode active material>
Among the carbonaceous materials, as the carbonaceous material used as the negative electrode active material,
(1) natural graphite,
(2) a carbonaceous material obtained by heat-treating an artificial carbonaceous material and an artificial graphite material at least once in the range of 400 to 3200 ° C;
(3) a carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different crystallinities and / or has an interface in contact with the different crystalline carbonaceous materials,
(4) A carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different orientations and / or has an interface in contact with the carbonaceous materials having different orientations,
Is preferably a good balance between initial irreversible capacity and high current density charge / discharge characteristics. Moreover, the carbonaceous materials (1) to (4) may be used alone or in combination of two or more in any combination and ratio.

  Examples of the artificial carbonaceous material and artificial graphite material of (2) above include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, those obtained by oxidizing these pitches, needle coke, pitch coke and Carbon materials that are partially graphitized, furnace black, acetylene black, organic pyrolysis products such as pitch-based carbon fibers, carbonizable organic materials and their carbides, or carbonizable organic materials are benzene, toluene, xylene, quinoline And a solution dissolved in a low-molecular organic solvent such as n-hexane, and carbides thereof.

As an alloy material used as the negative electrode active material, as long as lithium can be occluded / released, lithium alone, simple metals and alloys forming lithium alloys, or oxides, carbides, nitrides, silicides, sulfides thereof Any of compounds such as phosphides and phosphides may be used and is not particularly limited.
The single metal and alloy forming the lithium alloy are preferably materials containing group 13 and group 14 metal / metalloid elements (that is, excluding carbon), more preferably aluminum, silicon and tin (hereinafter referred to as “ Single metal) and alloys or compounds containing these atoms.
These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

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

  Examples of the composite compound include compounds that are complexly bonded to several elements such as a simple metal, an alloy, or a nonmetallic element. Specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. In the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element can also be used. .

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

  The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium, but a material containing titanium and lithium is preferable from the viewpoint of high current density charge / discharge characteristics, A lithium-containing composite metal oxide material containing titanium is more preferable, and a composite oxide of lithium and titanium (hereinafter sometimes referred to as “lithium titanium composite oxide”) is more preferable. That is, it is particularly preferable to use a lithium titanium composite oxide having a spinel structure in a negative electrode active material for a non-aqueous electrolyte battery because the output resistance is greatly reduced.

In addition, lithium or titanium of the lithium titanium composite oxide is at least selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. Also preferred are metal oxides substituted with one element.
The metal oxide is a lithium titanium composite oxide represented by the formula (A), and in the formula (A), 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, 0 ≦ It is preferable that z ≦ 1.6 because the structure upon doping and dedoping of lithium ions is stable.

Li _x Ti _y M _z O ₄ (A)
(In the formula, M represents at least one element selected from the group consisting of Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb.)

Among the compositions represented by the above formula (A),
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
This structure is particularly preferable because of a good balance of battery performance.

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

<Physical properties of carbonaceous materials>
When using a carbonaceous material as a negative electrode active material, it is desirable to have the following physical properties.

(X-ray parameters)
The d value (interlayer distance) of the lattice plane (002) determined by X-ray diffraction by the Gakushin method of carbonaceous materials is preferably 0.335 nm or more, and is usually 0.360 nm or less. 350 nm or less is preferable and 0.345 nm or less is more preferable. Further, the crystallite size (Lc) of the carbonaceous material obtained by X-ray diffraction by the Gakushin method is preferably 1.0 nm or more, and more preferably 1.5 nm or more.

(Volume-based average particle size)
The volume-based average particle diameter of the carbonaceous material is a volume-based average particle diameter (median diameter) obtained by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and 7 μm. The above is particularly preferable, and is usually 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 25 μm or less.

If the volume-based average particle size is below the above range, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, when the above range is exceeded, when an electrode is produced by coating, an uneven coating surface tends to be formed, which may be undesirable in the battery production process.
The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20) sorbitan monolaurate, which is a surfactant, and laser diffraction / scattering particle size distribution. This is carried out using a meter (LA-700 manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material.

(Raman R value, Raman half width)
The Raman R value of the carbonaceous material is a value measured using an argon ion laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, and particularly preferably 0.5 or less.

Further, the Raman half-width in the vicinity of 1580 cm ^{−1 of the} carbonaceous material is not particularly limited, but is usually 10 cm ⁻¹ or more, preferably 15 cm ⁻¹ or more, and usually 100 cm ⁻¹ or less, and 80 cm ⁻¹ or less. Preferably, 60 cm ⁻¹ or less is more preferable, and 40 cm ⁻¹ or less is particularly preferable.

  The Raman R value and the Raman half width are indices indicating the crystallinity of the surface of the carbonaceous material, but the carbonaceous material has an appropriate crystallinity from the viewpoint of chemical stability, and Li enters through charge and discharge. It is preferable that the crystallinity is such that the sites between the layers are not lost, that is, the charge acceptability is not lowered. In the case where the density of the negative electrode is increased by press after applying to the current collector, it is preferable to take account of this because crystals tend to be oriented in a direction parallel to the electrode plate. When the Raman R value or the Raman half width is in the above range, a suitable film can be formed on the negative electrode surface to improve the storage characteristics, cycle characteristics, and load characteristics, and the efficiency associated with the reaction with the nonaqueous electrolyte solution Reduction and gas generation can be suppressed.

The measurement of the Raman spectrum, using a Raman spectrometer (manufactured by JASCO Corporation Raman spectrometer), the sample is naturally dropped into the measurement cell and filled, and while irradiating the sample surface in the cell with argon ion laser light, This is done by rotating the cell in a plane perpendicular to the laser beam. The resulting Raman spectrum, the intensity Ia of the peak PA around 1580 cm ^-1, and measuring the intensity Ib of the peak PB around 1360 cm ^-1, and calculates the intensity ratio R (R = Ib / Ia) . The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material in the present invention. Further, the half width of the peak P _A in the vicinity of 1580 cm ^-1 of the resulting Raman spectrum was measured, which is defined as the Raman half-value width of the carbonaceous material in the present invention.

The Raman spectroscopic analysis measurement conditions are as follows.
Argon ion laser wavelength: 514.5nm
・ Laser power on the sample: 15-25mW
・ Resolution: 10-20cm ^-1
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
・ Raman R value, Raman half width analysis: Background processing ・ Smoothing processing: Simple average, 5 points of convolution

(BET specific surface area)
BET specific surface area of the carbonaceous material is a value of the measured specific surface area using the BET method is usually 0.1 m ² · ^{g -1} or more, 0.7 m ² · ^{g -1} or more, 1. 0 m ² · ^{g -1} or more, and particularly preferably 1.5 m ² · ^{g -1} or more, generally not more than 100 m ² · ^{g -1,} preferably ^{25 m} 2 · ^{g -1} or less, 15 m ² · g ^-1 more preferably less, ^{10 m} 2 · ^{g -1} or less are especially preferred.
When the value of the BET specific surface area is in the above range, lithium deposition on the electrode surface can be suppressed and gas generation due to reaction with the non-aqueous electrolyte can be suppressed.

  The specific surface area was measured by the BET method using a surface area meter (a fully automated surface area measuring device manufactured by Riken Okura), preliminarily dried at 350 ° C. for 15 minutes in a nitrogen gas stream, and then nitrogen with respect to atmospheric pressure. A nitrogen adsorption BET one-point method using a gas flow method is performed using a nitrogen-helium mixed gas that is accurately adjusted so that the relative pressure value of the gas becomes 0.3. The specific surface area determined by the measurement is defined as the BET specific surface area of the carbonaceous material in the present invention.

(Roundness)
When the circularity is measured as the degree of the sphere of the carbonaceous material, it is preferably within the following range. The circularity is defined as “circularity = (peripheral length of an equivalent circle having the same area as the particle projection shape) / (actual perimeter of the particle projection shape)”, and is theoretical when the circularity is 1. Become a true sphere.
The circularity of the particles having a particle size of 3 to 40 μm in the range of the carbonaceous material is desirably closer to 1, and is preferably 0.1 or more, more preferably 0.5 or more, and more preferably 0.8 or more, 0.85 or more is more preferable, and 0.9 or more is particularly preferable.

As for the high current density charge / discharge characteristics, the greater the circularity, the more the filling property is improved and the resistance between particles can be suppressed. Therefore, the high current density charge / discharge characteristics are improved. Therefore, it is preferable that the circularity is as high as the above range.
The circularity is measured using a flow type particle image analyzer (FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample was dispersed in a 0.2% by mass aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate as a surfactant, and irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. The detection range is specified as 0.6 to 400 μm, and the particle size is measured in the range of 3 to 40 μm. The circularity obtained by the measurement is defined as the circularity of the carbonaceous material in the present invention.

  The method for improving the circularity is not particularly limited, but a sphere-shaped sphere is preferable because the shape of the interparticle void when the electrode body is formed is preferable. Examples of spheroidizing treatment include a method of mechanically approaching a sphere by applying a shearing force and a compressive force, a mechanical / physical processing method of granulating a plurality of fine particles by the binder or the adhesive force of the particles themselves, etc. Is mentioned.

(Tap density)
The tap density of the carbonaceous material is usually 0.1 g · cm ⁻³ or more, preferably 0.5 g · cm ⁻³ or more, more preferably 0.7 g · cm ⁻³ or more, and 1 g · cm ⁻³ or more. Particularly preferable, 2 g · cm ⁻³ or less is preferable, 1.8 g · cm ⁻³ or less is more preferable, and 1.6 g · cm ⁻³ or less is particularly preferable. When the tap density is in the above range, battery capacity can be ensured and increase in resistance between particles can be suppressed.

The tap density is measured by passing through a sieve having an opening of 300 μm, dropping the sample onto a 20 cm ³ tapping cell and filling the sample to the upper end surface of the cell, and then measuring a powder density measuring device (for example, manufactured by Seishin Enterprise Co., Ltd.). Using a tap denser, tapping with a stroke length of 10 mm is performed 1000 times, and the tap density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the carbonaceous material in the present invention.

(Orientation ratio)
The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more, more preferably 0.015 or more, and usually 0.67 or less. When the orientation ratio is in the above range, excellent high-density charge / discharge characteristics can be ensured. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. Set the molding obtained by filling 0.47 g of the sample into a molding machine with a diameter of 17 mm and compressing it with 58.8 MN · m ^{-2 so} that it is flush with the surface of the sample holder for measurement. X-ray diffraction is measured. From the (110) diffraction and (004) diffraction peak intensities of the obtained carbon, a ratio represented by (110) diffraction peak intensity / (004) diffraction peak intensity is calculated. The orientation ratio calculated by the measurement is defined as the orientation ratio of the carbonaceous material in the present invention.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree / measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds

(Aspect ratio (powder))
The aspect ratio of the carbonaceous material is usually 1 or more and usually 10 or less, preferably 8 or less, and more preferably 5 or less. Within the above range, streaking during electrode plate formation is suppressed and more uniform coating is possible, so that excellent high current density charge / discharge characteristics can be ensured. The lower limit of the above range is the theoretical lower limit value of the aspect ratio of the carbonaceous material.

  The aspect ratio is measured by magnifying and observing particles of the carbonaceous material with a scanning electron microscope (SEM). Carbonaceous material particles when three-dimensional observation is performed by selecting arbitrary 50 graphite particles fixed to the end face of a metal having a thickness of 50 μm or less and rotating and tilting the stage on which the sample is fixed. The longest diameter A and the shortest diameter B orthogonal thereto are measured, and the average value of A / B is obtained. The aspect ratio (A / B) obtained by the measurement is defined as the aspect ratio of the carbonaceous material in the present invention.

<Configuration and production method of negative electrode>
Any known method can be used for producing the negative electrode 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 a negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can do.
In the case of using an alloy-based material, a method of forming a thin film layer (negative electrode active material layer) containing the above-described negative electrode active material by a method such as vapor deposition, sputtering, or plating is also used.

(Current collector)
As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the negative electrode current collector include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is particularly preferable from the viewpoint of ease of processing and cost.
In addition, the shape of the current collector may be, for example, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, or the like when the current collector is a metal material. Among them, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable, and both can be used as a current collector.

  The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and usually 100 μm or less, preferably 50 μm or less, from the viewpoint of securing battery capacity and handling properties.

(Thickness ratio between current collector and negative electrode active material layer)
The ratio of the thickness of the current collector to the negative electrode active material layer is not particularly limited, but the value of “(the thickness of the negative electrode active material layer on one side immediately before non-aqueous electrolyte injection) / (current collector thickness)” However, 150 or less is preferable, 20 or less is more preferable, 10 or less is particularly preferable, 0.1 or more is preferable, 0.4 or more is more preferable, and 1 or more is particularly preferable. When the ratio of the thickness of the current collector to the negative electrode active material layer is in the above range, the battery capacity can be maintained and heat generation of the current collector during high current density charge / discharge can be suppressed.

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

  The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, 15% by mass. The following is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is particularly preferable. When the ratio of the binder to the negative electrode active material is within the above range, the battery capacity and the strength of the negative electrode can be sufficiently secured.

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

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

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

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

  When the thickener is used, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Usually, it is 5 mass% or less, 3 mass% or less is preferable, and 2 mass% or less is more preferable. When the ratio of the thickener to the negative electrode active material is in the above range, it is possible to suppress a decrease in battery capacity and an increase in resistance, and it is possible to ensure good coatability.

(Electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. When the density of the negative electrode active material existing on the current collector is in the above range, the negative electrode active material particles are prevented from being destroyed, and an increase in initial irreversible capacity or to the vicinity of the current collector / negative electrode active material interface. The deterioration of the high current density charge / discharge characteristics due to the decrease in the permeability of the nonaqueous electrolyte solution can be suppressed, and the decrease in battery capacity and the increase in resistance can be suppressed.

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

(Surface coating of negative electrode plate)
You may use what attached the substance of the composition different from this to the surface of the said negative electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

2-2. Positive electrode <positive electrode active material>
The positive electrode active material used for the positive electrode is described below.
(composition)
The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

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

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

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

(Surface coating)
A material in which a material having a composition different from this (hereinafter referred to as “surface adhering material”) is attached to the surface of the positive electrode active material may be used. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

  For example, these surface adhering substances are dissolved or suspended in a solvent, impregnated and added to the positive electrode active material, and dried. After the surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material, It can be made to adhere to the surface of the positive electrode active material by a method of reacting by heating or the like, a method of adding to the positive electrode active material precursor and firing simultaneously. In addition, when attaching carbon, the method of attaching carbonaceous material mechanically later, for example in the form of activated carbon etc. can also be used.

  The amount of the surface adhering substance is preferably 0.1 ppm or more, more preferably 1 ppm or more, further preferably 10 ppm or more, and preferably 20% or less, more preferably 10% by mass with respect to the positive electrode active material. Hereinafter, it is more preferably used at 5% or less. By the surface adhesion substance, an effect of suppressing the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material can be obtained, and the battery life can be improved, but if the adhesion amount is too small, the effect is not sufficiently expressed, On the other hand, when the adhesion amount is too large, the interfacial resistance may increase in order to inhibit the entry and exit of lithium ions.

  In the present invention, the “positive electrode active material” includes a material having a composition different from the surface attached to the surface of the positive electrode active material.

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

(Tap density)
The tap density of the positive electrode active material is preferably 0.5 g / cm ³ or more, more preferably 0.8 g / cm ³ or more, and further preferably 1.0 g / cm ³ or more. When the tap density of the positive electrode active material is within the above range, it is possible to suppress the amount of dispersion medium and the necessary amount of conductive material and binder required when forming the positive electrode active material layer. As a result, the filling rate of the positive electrode active material In addition, battery capacity can be secured.
By using a complex oxide powder having a high tap density, a high-density positive electrode active material layer can be formed. In general, the tap density is preferably as high as possible, and there is no particular upper limit. However, the tap density is preferably 4.0 g / cm ³ or less, more preferably 3.7 g / cm ³ or less, and even more preferably 3.5 g / cm ³ or less. When it is within the above range, it is possible to suppress a decrease in load characteristics.

  In the present invention, the tap density is determined as the powder packing density (tap density) g / cc when 5 to 10 g of the positive electrode active material powder is put in a 10 ml glass graduated cylinder and tapped 200 times with a stroke of about 20 mm. The tap density calculated by the measurement is defined as the tap density of the positive electrode active material in the present invention.

(Median diameter d50)
The median diameter d50 of the positive electrode active material particles (secondary particle diameter when primary particles are aggregated to form secondary particles) is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably. It is 0.8 μm or more, most preferably 1.0 μm or more, preferably 30 μm or less, more preferably 27 μm or less, further preferably 25 μm or less, and most preferably 22 μm or less. Within the above range, a high tap density product can be obtained and the battery performance can be prevented from lowering. At the same time, the positive electrode of the battery is produced, that is, when the active material and the conductive material or binder are slurried with a solvent and applied in a thin film form. Problems such as streaking can be prevented. Here, by mixing two or more kinds of the positive electrode active materials having different median diameters d50, it is possible to further improve the filling property when forming the positive electrode.

  In the present invention, the median diameter d50 is measured by a known laser diffraction / scattering particle size distribution measuring apparatus. When LA-920 manufactured by HORIBA is used as a particle size distribution meter, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as a dispersion medium for measurement, and a measurement refractive index of 1.24 is set after ultrasonic dispersion for 5 minutes. Measured.

(Average primary particle size)
When primary particles are aggregated to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.8 μm. It is 2 μm or more, preferably 5 μm or less, more preferably 4 μm or less, further preferably 3 μm or less, and most preferably 2 μm or less. When it is in the above range, powder filling property and specific surface area can be ensured, deterioration of battery performance can be suppressed, and reversibility of charge / discharge can be ensured by obtaining appropriate crystallinity. .

  In the present invention, the primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000 times, the longest value of the intercept by the left and right boundary lines of the primary particles with respect to the horizontal straight line is obtained for any 50 primary particles and obtained by taking the average value. It is done.

(BET specific surface area)
The BET specific surface area of the positive electrode active material is preferably 0.1 m ² / g or more, more preferably 0.2 m ² / g or more, still more preferably 0.3 m ² / g or more, and 50 m ² / g or less. , Preferably 40 m ² / g or less, more preferably 30 m ² / g or less. When the BET specific surface area is in the above range, the battery performance can be secured and the applicability of the positive electrode active material can be kept good.

  In the present invention, the BET specific surface area is measured with a surface area meter (for example, a fully automatic surface area measuring device manufactured by Ritsu Okura), and after preliminary drying at 150 ° C. for 30 minutes in a nitrogen gas stream with respect to the sample, It is defined as a value measured by a nitrogen adsorption BET one-point method using a gas flow method, using a nitrogen-helium mixed gas adjusted accurately so that the value of the relative pressure of nitrogen is 0.3. The specific surface area determined by the measurement is defined as the BET specific surface area of the positive electrode active material in the present invention.

(Method for producing positive electrode active material)
As a manufacturing method of the positive electrode active material, a general method is used as a manufacturing method of the inorganic compound. In particular, various methods are conceivable for preparing a spherical or elliptical active material. For example, a transition metal source material is dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring. And a spherical precursor is prepared and recovered, and dried as necessary. Then, a Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ is added, and the active material is obtained by baking at a high temperature. .

For the production of the positive electrode, the positive electrode active material may be used alone, or one or more of different compositions may be used in any combination or ratio. Preferred combinations in this case include LiCoO ₂ and LiMn ₂ O ₄ or a part of this Mn substituted with another transition metal (for example, LiNi _0.33 Co _0.33 Mn _0.33 O ₂ ) Or a combination with LiCoO ₂ or a part of this Co substituted with another transition metal or the like.

<Configuration and manufacturing method of positive electrode>
The structure of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. Manufacture of the positive electrode using a positive electrode active material can be performed by a conventional method. That is, a positive electrode active material, a binder, and, if necessary, a conductive material and a thickener mixed in a dry form into a sheet form are pressure-bonded to the positive electrode current collector, or these materials are liquid media As a slurry by dissolving or dispersing in a positive electrode current collector, this is applied to a positive electrode current collector and dried to form a positive electrode active material layer on the current collector, thereby obtaining a positive electrode.

  The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. Moreover, Preferably it is 99 mass% or less, More preferably, it is 98 mass% or less. Within the above range, the electric capacity of the positive electrode active material in the positive electrode active material layer can be secured, and the strength of the positive electrode can be maintained.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1.5 g / cm ³ or more, more preferably 2 g / cm ³ , still more preferably 2.2 g / cm ³ or more, and preferably 5 g / cm ³ or less. Preferably it is 4.5 g / cm < ³ > or less, More preferably, it is the range of 4 g / cm < ³ > or less. Within the above range, good charge / discharge characteristics can be obtained, and an increase in electrical resistance can be suppressed.

(Conductive material)
A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios. The conductive material is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and usually 50% by mass or less, preferably 30% by mass in the positive electrode active material layer. % Or less, more preferably 15% by mass or less. Sufficient electrical conductivity and battery capacity can be ensured within the above range.

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

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

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

  In particular, when an aqueous solvent is used, it is preferable to make a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios. When a thickener is further added, the ratio of the thickener to the active material is 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more. It is 5 mass% or less, Preferably it is 3 mass% or less, More preferably, it is the range of 2 mass% or less. When it is in the above range, good coatability can be obtained, and a decrease in battery capacity and an increase in resistance can be suppressed.

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

  Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, and foam metal in the case of a metal material. A thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape. Although the thickness of the thin film is arbitrary, from the viewpoint of strength and handleability as a current collector, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, more Preferably it is 50 micrometers or less.

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

(Electrode area)
When using the non-aqueous electrolyte of the present invention, it is preferable that the area of the positive electrode active material layer is larger than the outer surface area of the battery outer case from the viewpoint of increasing the stability at high output and high temperature. Specifically, the sum of the electrode areas of the positive electrode with respect to the surface area of the exterior of the secondary battery is preferably 15 times or more, and more preferably 40 times or more.
The outer surface area of the outer case is the total area obtained by calculation from the vertical, horizontal, and thickness dimensions of the case part filled with the power generation element excluding the protruding part of the terminal in the case of a bottomed square shape. . In the case of a bottomed cylindrical shape, the geometric surface area approximates the case portion filled with the power generation element excluding the protruding portion of the terminal as a cylinder.
The total electrode area of the positive electrode is the geometric surface area of the positive electrode mixture layer facing the mixture layer containing the negative electrode active material, and in the structure in which the positive electrode mixture layer is formed on both sides via the current collector foil. , The sum of the areas where each surface is calculated separately.

(Thickness of positive plate)
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the composite layer obtained by subtracting the thickness of the metal foil of the core is preferably 10 μm with respect to one side of the current collector. As mentioned above, More preferably, it is 20 micrometers or more, Preferably it is 500 micrometers or less, More preferably, it is 450 micrometers or less.

2-3. Separator Normally, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, a resin, glass fiber, inorganic material, etc. formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention is used, and a porous sheet or a nonwoven fabric-like material having excellent liquid retention is used. Is preferred.

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

  The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. Within the above range, it is possible to ensure insulation and mechanical strength, as well as battery performance such as rate characteristics and energy density.

  When a porous material such as a porous sheet or nonwoven fabric is used as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Usually, it is 90% or less, preferably 85% or less, and more preferably 75% or less. When the porosity is in the above range, insulation and mechanical strength can be ensured, and at the same time, film resistance can be suppressed and good rate characteristics can be obtained.

  The average pore diameter of the separator is also arbitrary, but is usually 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. If the average pore diameter exceeds the above range, a short circuit tends to occur. When the average pore diameter is in the above range, the film resistance can be suppressed and good rate characteristics can be obtained while preventing a short circuit. On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

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

2-4. Battery design <electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed through the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape through the separator. Either is acceptable. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is usually 40% or more, preferably 50% or more, and usually 90% or less, preferably 80% or less. .
When the electrode group occupancy is in the above range, the battery capacity can be secured and the deterioration of characteristics such as charge / discharge repetition performance and high temperature storage accompanying the increase in internal pressure can be suppressed, and further the operation of the gas release valve can be prevented. Can do.

<Current collection structure>
The current collecting structure is not particularly limited, but is preferably a structure that reduces the resistance of the wiring portion and the joint portion.

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

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

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

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

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

<Example 1-1, Comparative Examples 1-1 to 1-3>
[Example 1-1]
[Preparation of non-aqueous electrolyte]
Content in non-aqueous electrolyte solution in a mixture (volume ratio 30:70) of ethylene carbonate (hereinafter sometimes referred to as EC) and dimethyl carbonate (hereinafter sometimes referred to as DMC) in a dry argon atmosphere As vinylene carbonate (hereinafter sometimes referred to as VC) 2% by mass, hexamethylene diisocyanate (hereinafter sometimes referred to as HMI) 0.3% by mass and vinylsulfonic acid-2-propynyl (hereinafter referred to as PVS) The electrolyte solution was prepared by mixing 0.3% by mass of LiPF ₆ and then dissolving LiPF ₆ sufficiently dried at a rate of 1.0 mol / liter.
[Production of positive electrode]
97% by mass of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and 1.5% by mass of polyvinylidene fluoride (PVdF) as a binder, N-methylpyrrolidone In a solvent, the mixture was slurried by mixing with a disperser. This was uniformly applied to both sides of a 21 μm thick aluminum foil, dried, and then pressed to obtain a positive electrode.

[Production of negative electrode]
100 parts by weight of graphite powder as the negative electrode active material, 1 part by weight of aqueous dispersion of sodium carboxymethyl cellulose (concentration of 1% by weight of sodium carboxymethyl cellulose) as the thickener and binder, respectively, and aqueous dispersion of styrene-butadiene rubber 1 part by mass (concentration of styrene-butadiene rubber 50% by mass) was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a 12 μm thick copper foil, dried, and then pressed to obtain a negative electrode.

[Preparation of non-aqueous electrolyte battery]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, the positive electrode, the separator, and the negative electrode to produce a battery element. After inserting this battery element into a bag made of a laminate film in which both surfaces of aluminum (thickness 40 μm) are coated with a resin layer while projecting positive and negative terminals, a non-aqueous electrolyte solution is injected into the bag, Vacuum sealing was performed to produce a sheet-like non-aqueous electrolyte battery. Furthermore, in order to improve the adhesion between the electrodes, the sheet-like battery was sandwiched between glass plates and pressurized.

[Initial capacity evaluation]
The non-aqueous electrolyte battery was charged at a constant current of up to 4.1 V at a current corresponding to 0.2 C at 25 ° C., then discharged to 3 V at a constant current of 0.2 C, and further at a current corresponding to 0.2 C. After constant current-constant voltage charge to 4.33 V (hereinafter referred to as “CCCV charge” as appropriate) (0.05 C cut), the battery was stabilized by discharging to 3 V at 0.2 C. Subsequently, after CCCV charge (0.05C cut) to 4.33V at 0.2C, it discharged again to 3V at 0.2C, and the initial capacity was obtained. Here, 1C represents a current value for discharging the reference capacity of the battery in one hour, and for example, 0.2C represents a current value of 1/5 thereof.

[High temperature storage characteristics evaluation]
After the initial capacity evaluation, the non-aqueous electrolyte battery was again CCCV charged (0.05 C cut) to 4.33 V, and then stored at 85 ° C. for 24 hours. After the battery was sufficiently cooled, it was immersed in an ethanol bath to measure its mass, and the amount of stored gas generated from the change in mass before and after storage was determined. This was defined as a storage gas amount (generated gas amount). Next, discharge at 25 ° C. to 3 V at 0.2 C, measure the remaining capacity after the high temperature storage characteristics test, determine the ratio of the remaining capacity to the initial discharge capacity, this is the remaining capacity (%) after high temperature storage did.
Using the produced non-aqueous electrolyte battery, high-temperature storage characteristics were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 1-1]
A non-aqueous electrolyte battery was produced in the same manner as in Example 1-1, except that an electrolyte solution containing no HMI or PVS was used in the electrolyte solution of Example 1-1, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. Carried out. The evaluation results are shown in Table 1.

[Comparative Example 1-2]
A non-aqueous electrolyte battery was produced in the same manner as in Example 1-1, except that an electrolyte not containing PVS was used in the electrolyte of Example 1-1, and an initial capacity evaluation and a high-temperature storage characteristic evaluation were performed. . The evaluation results are shown in Table 1.

[Comparative Example 1-3]
A non-aqueous electrolyte battery was produced in the same manner as in Example 1-1, except that an electrolyte containing no HMI was used in the electrolyte of Example 1-1, and an initial capacity evaluation and a high-temperature storage characteristic evaluation were performed. . The evaluation results are shown in Table 1.

From Table 1, when the nonaqueous electrolytic solution of Example 1-1 according to the present invention is used, the compound represented by the general formula (1) and the compound having at least two isocyanate groups in the molecule are not added. It can be seen that compared to (Comparative Example 1-1), the generation amount of the storage gas is low and the residual / recovery capacity after high-temperature storage is excellent. Further, when a compound having at least two isocyanate groups in the molecule or a compound represented by the general formula (1) is added alone (Comparative Examples 1-2 to 1-3), the amount of stored gas generated・ Although there is an effect of improving the remaining capacity, it is found that the battery is insufficient.

<Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-4>
[Example 2-1]
In Example 1-1, a mixture of EC, monofluoroethylene carbonate (hereinafter sometimes referred to as MFEC) and DMC (volume ratio 15:15:70) in a non-aqueous electrolyte solution under a dry argon atmosphere. As a content, VC 1% by mass, HMI 0.3% by mass and methanesulfonic acid-2-propynyl (hereinafter sometimes referred to as PMS) 0.3% by mass were mixed, and then fully dried LiPF ₆ was added 1 A non-aqueous electrolyte battery was prepared in the same manner as in Example 1-1 except that the electrolyte was prepared by dissolving at a rate of 0.0 mol / liter, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. . The evaluation results are shown in Table 2.

[Example 2-2]
A non-aqueous electrolyte battery was produced in the same manner as in Example 2-1, except that PVS was used instead of PMS in the electrolyte solution of Example 2-1, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. The evaluation results are shown in Table 2.

[Comparative Example 2-1]
A non-aqueous electrolyte battery was prepared in the same manner as in Example 2-1, except that an electrolyte solution containing no HMI or PMS was used in the electrolyte solution of Example 2-1, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. Carried out. The evaluation results are shown in Table 2.

[Comparative Example 2-2]
A non-aqueous electrolyte battery was produced in the same manner as in Example 2-1, except that an electrolyte containing no PMS was used in the electrolyte of Example 2-1, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. . The evaluation results are shown in Table 2.

[Comparative Example 2-3]
A non-aqueous electrolyte battery was produced in the same manner as in Example 2-1, except that an electrolyte containing no HMI was used in the electrolyte of Example 2-1, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. . The evaluation results are shown in Table 2.

[Comparative Example 2-4]
A non-aqueous electrolyte battery was produced in the same manner as in Example 2-2 except that an electrolyte solution containing no HMI was used in the electrolyte solution of Example 2-2, and initial capacity evaluation and high-temperature storage characteristic evaluation were performed. . The evaluation results are shown in Table 2.

  From Table 2, when the non-aqueous electrolyte solution of Examples 2-1 to 2-2 according to the present invention is used, the compound represented by the general formula (1) and the compound having at least two isocyanate groups in the molecule are added. It can be seen that the amount of generated storage gas is low and the residual / recovery capacity after high-temperature storage is excellent as compared with the case where it is not performed (Comparative Example 2-1). Further, when a compound having at least two isocyanate groups in the molecule or a compound represented by the general formula (1) is added alone (Comparative Examples 2-2 to 2-4), the amount of stored gas generated・ Although there is an effect of improving the remaining capacity, it is found that the battery is insufficient.

<Example 3-1 and Comparative Examples 3-1 to 3-3>
[Example 3-1]
In the electrolytic solution of Example 2-1, 0.5 mass% of 2- (methanesulfonyloxy) propionic acid-2-propynyl (hereinafter sometimes referred to as PMP) was used instead of 0.3 mass% of PMS. A nonaqueous electrolyte battery was produced in the same manner as in Example 2-1.

[Comparative Example 3-1]
A non-aqueous electrolyte battery was produced in the same manner as in Example 3-1, except that the electrolyte solution of Example 3-1 did not contain HMI and PMP [Comparative Example 3-2]
A non-aqueous electrolyte battery was produced in the same manner as in Example 3-1, except that an electrolytic solution containing no PMP was used in the electrolytic solution of Example 3-1.
[Comparative Example 2-3]
A non-aqueous electrolyte battery was produced in the same manner as in Example 3-1, except that an electrolyte containing no HMI was used in the electrolyte of Example 3-1.

[Initial rate evaluation]
The non-aqueous electrolyte battery was charged at a constant current up to 4.1 V at a current corresponding to 0.2 C at 60 ° C. After that, at 25 ° C., it was discharged to 3V with a constant current of 0.2C, and further CCCV charged to 0.053V (0.05C cut) with a current corresponding to 0.2C, and then discharged to 3V at 0.2C. To stabilize the battery. Subsequently, after CCCV charge (0.05C cut) to 4.33V at 0.2C, it discharged again to 3V at 0.2C, and the initial capacity was obtained.
Again, after CCCV charge (0.05C cut) to 4.33V at 0.2C, it was discharged again to 3V at 0.5C to determine the initial 0.5C capacity. Then, an initial rate (%) was obtained from a calculation formula of (initial 0.5 C capacity) / (initial capacity) × 100.

[Rate evaluation after high temperature storage]
The non-aqueous electrolyte battery after the initial capacity evaluation was performed again with CCCV charge (0.05 C cut) to 4.33 V, and then stored at 85 ° C. for a predetermined time. After the battery was sufficiently cooled, it was immersed in an ethanol bath to measure its mass, and the amount of stored gas generated from the change in mass before and after storage was determined. This was defined as a storage gas amount (generated gas amount). Next, discharge at 25 ° C to 3V at 0.2C, then charge CCCV to 0.053V at 0.2C (0.05C cut), and then discharge again to 3V at 0.2C. Asked.
Again, after CCCV charge (0.05 C cut) to 4.33 V at 0.2 C, it was discharged again to 3 V at 0.5 C, and 0.5 C capacity was determined after storage. Then, the post-storage rate (%) was obtained from the formula of (0.5 C capacity after storage) ÷ (capacity after storage) × 100.
Using the non-aqueous electrolyte battery produced above, an initial rate evaluation and a rate evaluation after high-temperature storage were performed. The evaluation results are shown in Table 3.

From Table 3, when the nonaqueous electrolytic solution of Example 3-1 according to the present invention is used, the compound represented by the general formula (1) and the compound having at least two isocyanate groups in the molecule are not added. Compared to (Comparative Example 3-1), the initial rate characteristics and post-storage rate characteristics are improved, and the amount of stored gas generated is also low. From this, when the non-aqueous electrolyte solution of Example 3-1 is used, a secondary battery having comprehensively excellent battery characteristics can be provided.
Moreover, when the compound which has at least 2 isocyanate group in a molecule | numerator, or the compound represented by General formula (1) is added independently (Comparative Examples 3-2 to 3-3), the storage gas suppression effect is Although it can be seen, the rate characteristics after initial or after storage are deteriorated, so that it is found that the battery is insufficient.

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

Claims (7)

A non-aqueous electrolyte solution for a non-aqueous electrolyte battery comprising a positive electrode and a negative electrode capable of inserting and extracting metal ions, the non-aqueous electrolyte solution together with an electrolyte and a non-aqueous solvent,
(A) A non-aqueous electrolyte containing a compound having at least two isocyanate groups in the molecule and (B) a compound represented by the following formula (1).

(In formula (1), R ¹ and R ² are each independently a hydrogen atom, a halogen atom, or an organic group that may have a substituent, and may be the same or different.)   The non-aqueous electrolyte solution according to claim 1, wherein the non-aqueous electrolyte solution contains the compound represented by the general formula (1) in an amount of 0.01% by mass to 5% by mass. 3. The non-aqueous electrolyte according to claim 1, wherein in the general formula (1), either R ¹ or R ² or both are organic groups containing one or more S═O groups. .   The compound having at least two isocyanate groups in the molecule is hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-4,4′-diisocyanate, bicyclo [2.2.1] heptane- 2,5-diylbis (methylisocyanate), bicyclo [2.2.1] heptane-2,6-diylbis (methylisocyanate), isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4 4. The non-reactive material according to claim 1, comprising at least one compound selected from the group consisting of 1,4-trimethylhexamethylene diisocyanate and a polyisocyanate compound derived therefrom. Aqueous electrolyte.   It further contains at least one compound selected from the group consisting of a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a monofluorophosphate, and a difluorophosphate. Item 5. The nonaqueous electrolytic solution according to any one of Items 1 to 4.   The cyclic carbonate having a fluorine atom contains at least one compound selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate, and has a carbon-carbon unsaturated bond. The nonaqueous electrolytic solution according to claim 5, wherein the cyclic carbonate has at least one compound selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, and ethynyl ethylene carbonate.   A non-aqueous electrolyte secondary battery comprising a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte according to any one of claims 1 to 6. A non-aqueous electrolyte secondary battery, characterized by being an electrolyte.