JP2013051198A - Nonaqueous electrolyte and nonaqueous electrolyte battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte which improves cycle characteristics and suppresses deterioration in high-temperature storage characteristics, and a nonaqueous electrolyte battery using the nonaqueous electrolyte.SOLUTION: The nonaqueous electrolyte comprising at least a lithium salt and a nonaqueous organic solvent is characterized by containing at least a diisocyanate compound (A) represented by general formula (1) and a cyclic carbonate (B) having a fluorine atom. (In the formula (1), A is an organic group with 4-15 carbon atoms which has one cycloalkylene group with 4-6 carbon atoms.)

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 electrolyte for a 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 , or a high dielectric constant such as ethylene carbonate or propylene carbonate is used. 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 Document 1 discloses 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.
Patent Document 2 discloses that by adding a compound having an isocyanate group and an unsaturated cyclic carbonate to a non-aqueous electrolyte, a film is formed stepwise on the negative electrode, and the cycle characteristics of the battery are improved. It is disclosed.
Patent Document 3 discloses a non-aqueous solution in which the positive electrode contains a positive electrode active material coated with phosphate, and the electrolytic solution contains an electrolytic solution containing a non-aqueous solvent, an electrolyte salt, and an isocyanate compound. It has been reported that by using an electrolyte secondary battery, the effect of suppressing swelling during high-temperature storage can be obtained.
Patent Document 4 discloses that the battery characteristics during high-temperature cycle are improved by using a nonaqueous electrolyte battery containing 50 to 1000 ppm of water in the positive electrode and the electrolyte containing an isocyanate compound and an aromatic compound. Has been reported.

JP 2005-259641 A JP 2006-164759 A JP 2011-014379 A JP 2011-028860 A

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 expanding the use range of the positive electrode to a high potential, or pressurizing and densifying the active material layer of the electrode to reduce the volume occupied by the active material other than the active material inside the battery as much as possible. A method is being considered. However, when the use range of the positive electrode is expanded to be used at 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 tends 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 non-aqueous solvents and electrolytes are used. Consideration has been made. In addition, when the electrode active material layer is pressurized and densified, it becomes difficult to use the active material uniformly, and some lithium is precipitated due to non-uniform reaction, or deterioration of the active material is promoted. As a result, a problem that sufficient characteristics cannot be obtained easily occurs.

Therefore, although it is calculated | required to suppress the deterioration of the said battery characteristic, when the additive described in patent document 1 is contained in a nonaqueous electrolyte, the side reaction of an additive will also advance simultaneously on a positive electrode and a negative electrode. As a result, there has been a problem that initial capacity and high-temperature storage characteristics deteriorate.
Even if the additive described in Patent Document 2 is contained in the non-aqueous electrolyte, the side reaction cannot be completely suppressed, and the cycle characteristics have not yet been satisfactory.
In addition, when the non-aqueous electrolytes described in Patent Documents 3 and 4 are used, a decrease in discharge capacity retention rate is observed when used under a high potential.

  Accordingly, 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 improvement in cycle characteristics and deterioration of high-temperature storage characteristics, and the non-aqueous electrolyte are used. It is an object of the present invention to provide a battery.

（式（１）中、Ａは炭素数４〜６のシクロアルキレン基を１つ有する炭素数４〜１５の有機基である。）
（ｂ）前記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種の化合物であ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）で表されるジイソシアネート化合物が、非水系電解液中に０．００１〜１０質量％含有されてい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）前記フッ素原子を有する環状カーボネート化合物が、非水系電解液中に０．１質量％以上含有されていることを特徴とする（ａ）乃至（ｃ）のいずれか１つに記載の非水系電解液。
（ｅ）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電池であって、該非水系電解液が請求項（ａ）乃至（ｄ）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電池。 As a result of various studies to achieve the above object, the present inventors have found that the above problems can be solved by including a specific compound in the electrolytic solution, and have completed the present invention. .
That is, the gist of the present invention is as follows.
(A) a non-aqueous electrolyte solution comprising at least a lithium salt and a non-aqueous organic solvent, wherein the non-aqueous electrolyte solution is at least (A) a diisocyanate compound represented by the following general formula (1), and (B) A non-aqueous electrolyte containing a cyclic carbonate having a fluorine atom.

(In Formula (1), A is a C4-C15 organic group which has one C4-C6 cycloalkylene group.)
(B) The cyclic carbonate having a fluorine atom is 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 (a).
(C) The nonisocyanate according to (a) or (b), wherein the diisocyanate compound represented by the general formula (1) is contained in a non-aqueous electrolyte solution in an amount of 0.001 to 10% by mass. Aqueous electrolyte.
(D) The non-aqueous electrolyte according to any one of (a) to (c), wherein the non-aqueous electrolyte contains the cyclic carbonate compound having a fluorine atom in an amount of 0.1% by mass or more. Aqueous electrolyte.
(E) A non-aqueous electrolyte battery including a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is any one of claims (a) to (d) A non-aqueous electrolyte battery, characterized in that it is a non-aqueous electrolyte solution described in 1.

According to the present invention, there is provided a non-aqueous electrolyte battery that has excellent charge / discharge characteristics under a high current density while suppressing capacity deterioration during storage at high temperatures and capacity deterioration during cycling of the non-aqueous electrolyte battery. be able to.
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 suppressing capacity deterioration during storage at high temperature and capacity deterioration during cycling, and Although the action and principle that can improve the excellent charge / discharge characteristics under high current density are not clear, it is considered as follows. However, the present invention is not limited to the operations and principles described below.
Conventionally, it has been known that when a compound having an isocyanate group described in Patent Documents 1 and 2 is used, a film derived from a compound having an isocyanate group is formed on the negative electrode. However, at the same time, deterioration due to electrochemical side reactions on the positive and negative electrodes progressed, and battery characteristics such as cycle characteristics, high-temperature storage characteristics, and charge / discharge characteristics under a high current density were not yet satisfactory. Moreover, although the cyclic carbonate which has a fluorine atom is reduced on a negative electrode, an organic anion compound is produced, but its stability is low. As a result, the battery characteristics deteriorate due to elution during high temperature storage or cycling, which is insufficient.
The present inventors pay attention to this point, and contain a diisocyanate compound represented by the general formula (1) (hereinafter sometimes abbreviated as a cyclic diisocyanate compound) and a cyclic carbonate having a fluorine atom in the nonaqueous electrolytic solution. Thus, it was found that capacity degradation during storage at high temperature and capacity degradation during cycling were suppressed, and charge / discharge characteristics under high current density were improved. An anionic compound and a cyclic diisocyanate compound produced by reduction of a cyclic carbonate having a fluorine atom interact to form a high-quality composite film. Furthermore, since the cyclic diisocyanate compound has a three-dimensionally large ring structure, the electrochemical side reaction at the positive and negative electrodes is difficult to proceed. As a result, the cycle characteristic and the high temperature storage characteristic improvement effect are remarkably exhibited.
That is, according to the present invention, a non-aqueous electrolyte battery excellent in cycle characteristics and high-temperature storage characteristics can be provided.

  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.

1. Non-aqueous electrolyte 1-1. The diisocyanate compound represented by the general formula (1) and the cyclic carbonate having a fluorine atom The nonaqueous electrolytic solution of the present invention contains at least a diisocyanate compound represented by the following general formula (1) and a cyclic carbonate having a fluorine atom. It is characterized by that.
<Diisocyanate compound represented by general formula (1)>

In the general formula (1), A is an organic group having 4 to 15 carbon atoms having one cycloalkylene group having 4 to 6 carbon atoms. The hydrogen atom on the cycloalkylene group may be substituted with a methyl group or an ethyl group. The diisocyanate group having a ring structure forms a composite film on the cyclic carbonate having a fluorine atom, which will be described later, and the negative electrode. In addition, since it has a cycloalkylene group having 4 to 6 carbon atoms and is a sterically bulky molecule, electrochemical side reactions are unlikely to occur on the positive and negative electrodes, resulting in cycle characteristics, high temperature storage characteristics and high current density. Under charge / discharge characteristics are improved.
Here, the organic group means a functional group composed of an atom selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom and a halogen atom, preferably a carbon atom composed of a carbon atom and a hydrogen atom. It is a hydrogen group.
The bonding site of the group bonded to the cycloalkylene group is not particularly limited and may be any of a meta position, a para position, and an ortho position, but is preferably a meta position. The cycloalkylene group is preferably a cyclopentylene group or a cyclohexylene group, and more preferably a cyclohexylene group.

  Moreover, it is preferable to have a C1-C3 alkylene group between a cycloalkylene group and an isocyanate group. By having an alkylene group, it becomes sterically bulky, so that side reactions on the positive electrode are less likely to occur. Furthermore, if the alkylene group has 1 to 3 carbon atoms, the ratio of the isocyanate group to the total molecular weight does not change greatly, and thus the effect of the present invention is remarkably easily exhibited.

  The molecular weight of the diisocyanate compound represented by the general 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 80 or more, more preferably 115 or more, still more preferably 170 or more, and 300 or less, more preferably 230 or less. If it is this range, it will be easy to ensure the solubility of the diisocyanate compound with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the diisocyanate compound is not particularly limited, and can be produced by arbitrarily selecting a known method. Moreover, you may use a commercial item.

Specific examples of the diisocyanate compound represented by the general formula (1) include the following compounds.

  These diisocyanate compounds having a cycloalkane structure form a composite film on the cyclic carbonate having a fluorine atom and the negative electrode. Furthermore, since it has a ring structure and is sterically bulky, it is a molecule, so that electrochemical side reactions on the positive and negative electrodes are unlikely to occur. As a result, cycle characteristics and high-temperature storage characteristics are improved, which is preferable.

これらのジイソシアネート化合物は、その分子の対称性からイソシアネート基の反応性が等しく、より重合度の高い安定な複合的な被膜が形成され、その結果、電池特性がさらに向上するため、より好ましい。 The diisocyanate compound represented by the general formula (1) is more preferably a compound shown below.

These diisocyanate compounds are more preferable because the reactivity of the isocyanate group is equal due to the symmetry of the molecule, and a stable composite film having a higher degree of polymerization is formed. As a result, the battery characteristics are further improved.

The diisocyanate compound used for this invention may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. There is no limitation on the amount of the diisocyanate compound based on 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. The content is 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 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 carbonate having a fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter sometimes abbreviated 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 derivatives thereof, and examples thereof include a fluorinated product of ethylene 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.

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate gives high ion conductivity and suitably forms an interface protective film. And more preferable.
A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

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. In addition, when fluorinated cyclic carbonate is used as the non-aqueous organic solvent, the blending amount is preferably 1% by volume or more, more preferably 5% by volume or more, and further preferably 10% by volume or more in 100% by volume of the non-aqueous solvent. In addition, it is preferably 40% by volume or less, more preferably 30% by volume or less, and still more 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 diisocyanate compound represented by the general formula (1) 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 diisocyanate compound represented by the general formula (1) and the fluorinated cyclic carbonate is preferably 0.4: 100 to 100: 100, The ratio is more preferably 1: 100 to 50: 100, and further preferably 1.4: 100 to 30: 100. 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.

1-2. Electrolyte <Lithium salt>
As the electrolyte used in the non-aqueous electrolyte solution of the present invention, 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, inorganic lithium salts LiTaF _6, LiWF ₇ and the like;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ 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 ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ Sulfonic acid lithium salts such as 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 metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, 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 , LiBF ₂ (CF ₃ SO ₂ ) ₂ , LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ Fluorine-containing organic lithium salts such as;
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 bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalate phosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C _{2 F 5, LiPF 3 (CF} 3) 3, LiPF 3 (C 2 F 5) 3 or the like is output characteristics and Haile DOO charge and discharge characteristics, high-temperature storage characteristics, particularly preferred from the viewpoint that an effect of improving the cycle characteristics and the like.

These lithium salts may be used alone or in combination of two or more. A preferred example in the case of using two or more types in combination is a combination of LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li, etc., and 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 as long as the amount of the present invention is not significantly impaired. On the other hand, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, while its upper limit is usually 30% by mass or less, preferably 20% by 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. Examples of the organic lithium salt include 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 bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalate phosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ or the like is preferable. In this case, the ratio of the organic lithium salt to 100% by mass of the whole non-aqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, preferably 30% by mass or less, particularly 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, but the electric conductivity of the electrolyte solution is in a good range, and good battery performance is ensured. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and further preferably 0.5 mol / L or more. Preferably it is 3 mol / L or less, More preferably, it is 2.5 mol / L or less, More preferably, it is 2.0 mol / L or less. If it is this range, since there is not too little lithium which is a charged particle and a viscosity can be made into an appropriate range, it will become easy to ensure favorable electrical conductivity.

1-3. Non-aqueous organic solvent There is no restriction | limiting in particular about the non-aqueous organic 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 have 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 lower limit of the blending amount when one kind is used alone is non-aqueous organic. In 100 volume% of solvent, it is 5 volume% or more, More preferably, it is 10 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, an upper limit is 95 volume% or less, More 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, and a dialkyl carbonate having 3 to 7 carbon atoms is more preferable.
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 abbreviated 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 organic 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. Further, the chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the non-aqueous organic 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 compounding 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 organic 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.
Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid-n- Examples include propyl and isopropyl isobutyrate.

  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 organic 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. The amount of the chain carboxylic acid ester is preferably 60% by volume or less, more preferably 50% by volume or less, in 100% by volume of the non-aqueous organic solvent. 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 portion of the chain ethers hydrogen 3-10 carbon atoms which may be substituted by fluorine, and cyclic ethers having 3 to 6 carbon atoms are preferred.

Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl Ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2, 2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl -N-propyl ether, (2,2,2-trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trifluoro Olo-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2 , 2,3,3,3-pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3 -Fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) ) (2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) Ether, di-n-propyl Ether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3 , 3-tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, ( 3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether , (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3 3,3-triflu (Ro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3,3-penta Fluoro-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-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fur Roethoxy) 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-tetrafluoroeth) Xyl) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2 -Fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2, 2,2-trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) Ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. And the like.

  Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane 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 5% by volume or more, more preferably 10% by volume or more, more preferably 15% by volume or more, and preferably 70% by volume or less in 100% by volume of the non-aqueous organic solvent. 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 compounds>
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.

  Examples of the cyclic sulfone having 3 to 6 carbon atoms include trimethylene sulfones, tetramethylene sulfones, hexamethylene sulfones as monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, hexamethylene disulfones as disulfone compounds, and the like. Is mentioned. 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.

  The sulfolane is preferably sulfolane and / or a sulfolane derivative (hereinafter sometimes abbreviated as “sulfolane” including sulfolane). 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.

  Examples of the chain sulfone having 2 to 6 carbon atoms include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone. , Diisopropylsulfone, n-butylmethylsulfone, n-butylethylsulfone, t-butylmethylsulfone, t-butylethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, monofluoroethylmethylsulfone , Difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone Ethyl trifluoromethyl sulfone, perfluoroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di (trifluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n- Propylsulfone, trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propyl Sulfone, pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl- - butyl sulfone, pentafluoroethyl -n- 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 preferred because a higher high output ionic conductivity.

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, further preferably 5% by volume or more in 100% by volume of the non-aqueous organic solvent, and preferably It is 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.

<When using a cyclic carbonate having a fluorine atom as a non-aqueous organic solvent>
In the present invention, when a cyclic carbonate having a fluorine atom is used as a non-aqueous organic solvent, one of the non-aqueous organic solvents exemplified above as a non-aqueous organic solvent other than the cyclic carbonate having a fluorine atom is cyclic having a fluorine atom. It may be used in combination with carbonate, or two or more may be used in combination with cyclic carbonate having a fluorine atom.
For example, a preferred combination of non-aqueous organic solvents includes 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 organic solvent is preferably 60% by volume or more, more preferably 80% by volume or more, further preferably 90% by volume or more, and fluorine. The ratio of the cyclic carbonate having a fluorine atom to the total of the cyclic carbonate having an atom 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. Yes, 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. Use of a combination of these non-aqueous organic solvents may improve the balance between cycle characteristics and high-temperature storage characteristics (particularly, remaining capacity and high-load discharge capacity after high-temperature storage) of a battery produced using the non-aqueous organic solvent. .

  For example, specific examples of preferred combinations of a cyclic carbonate having a fluorine atom and a chain carbonate include monofluoroethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and diethyl carbonate, monofluoroethylene carbonate and ethyl methyl carbonate, and monofluoroethylene carbonate. And dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, and the like.

  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 organic solvent is preferably 10% by volume or more, more preferably 15% by volume or more, and further preferably 20% by volume. 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%. The volume is not less than volume%, more preferably not less than 25 volume%, preferably not more than 95 volume%, more preferably not more than 85 volume%, still more preferably not more than 75 volume%, particularly preferably not more than 60 volume%. When a cyclic carbonate having no fluorine atom is contained in this concentration range, the electrical conductivity of the electrolytic solution can be secured while forming a stable protective film on the negative electrode.

  For example, specific examples of preferable combinations of a cyclic carbonate having a fluorine atom and a cyclic carbonate having no fluorine atom and a chain carbonate include monofluoroethylene carbonate, ethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and ethylene carbonate, Diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene Carbonate and diethyl carbonate and ethyl Cyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate and dimethyl carbonate, monofluoroethylene carbonate, propylene carbonate and diethyl carbonate, monofluoroethylene carbonate and propylene carbonate And ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate and diethyl carbonate Bonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate and dimethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate and diethyl Carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate and propylene carbonate -Bonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate It is done.

  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 preferable, in particular, monofluoroethylene Carbonate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, Ethylene carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene -Bonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate monofluoroethylene Monofluoroethylene carbonates such as carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and symmetrical chain cars Those containing sulfonates and asymmetric linear carbonate is preferred because a good balance between cycle characteristics and large-current discharge characteristics. 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 organic solvent, the proportion of dimethyl carbonate in the total non-aqueous organic solvent is preferably 10% by volume or more, more preferably 20% by volume or more, and further preferably 25% by volume. % Or more, particularly preferably 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. If contained, 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 battery characteristics after high-temperature storage are improved while ensuring the electrical conductivity of the electrolyte. This is preferable.

  The volume ratio of dimethyl carbonate to ethyl methyl carbonate (dimethyl carbonate / ethyl methyl carbonate) in all non-aqueous organic solvents is 1.1 in terms of improving the electric conductivity of the electrolytic solution and improving the battery characteristics after storage. The above is preferable, 1.5 or more is more preferable, and 2.5 or more is still 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 aromatic fluorine-containing solvents may be mixed.

<When using a cyclic carbonate having a fluorine atom as an auxiliary agent>
In the present invention, when a cyclic carbonate having a fluorine atom is used as an auxiliary agent, the above-exemplified nonaqueous organic solvent may be used alone as the nonaqueous organic solvent other than the cyclic carbonate having a fluorine atom. You may use a seed or more together by arbitrary combinations and ratios.
For example, a preferred combination of non-aqueous organic solvents includes a combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate. Among them, the total of the cyclic carbonate having no fluorine atom and the chain carbonate in the non-aqueous organic solvent is preferably 70% by volume or more, more preferably 80% by volume or more, and further 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 Is 50% by volume or less, more preferably 35% by volume or less, still more preferably 30% by volume or less, and particularly preferably 25% by volume or less. Use of a combination of these non-aqueous organic solvents may improve the balance between cycle characteristics and high-temperature storage characteristics (particularly, remaining capacity and high-load discharge capacity after high-temperature storage) of a battery produced using the non-aqueous organic solvent. .

For example, specific examples of preferable combinations of cyclic carbonate and chain carbonate having no fluorine atom include ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate and diethyl. Examples thereof include carbonate, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

  Among the combinations of cyclic carbonates and chain carbonates having no 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 organic solvent is preferably 0.1% by volume or more, more preferably 1% by volume or more, still more preferably 2% by volume or more, and preferably 20% by volume or less, more Preferably it is 8 volume% or less, More preferably, it is 5 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 organic solvent, the proportion of dimethyl carbonate in the total non-aqueous organic solvent is preferably 10% by volume or more, more preferably 20% by volume or more, and further preferably 25% by volume. % Or more, particularly preferably 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. If contained, 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 battery characteristics after high-temperature storage are improved while ensuring the electrical conductivity of the electrolyte. This is preferable.

The volume ratio of dimethyl carbonate to ethyl methyl carbonate (dimethyl carbonate / ethyl methyl carbonate) in all non-aqueous organic solvents is 1.1 in terms of improving the electric conductivity of the electrolytic solution and improving the battery characteristics after storage. The above is preferable, 1.5 or more is more preferable, and 2.5 or more is still 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 the present specification, the volume of the non-aqueous organic 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.

1-4. Auxiliary Agent In the non-aqueous electrolyte battery of the present invention, an auxiliary agent may be appropriately used depending on the purpose in addition to the diisocyanate compound represented by the general formula (1) and the cyclic carbonate having a fluorine atom. As auxiliary agents, the following cyclic carbonates having a carbon-carbon unsaturated bond, monofluorophosphates and difluorophosphates, compounds having a nitrile group, isocyanate compounds other than the general formula (1), overcharge prevention Agents, other auxiliaries, and the like.

<Cyclic carbonate having a carbon-carbon unsaturated bond>
As the cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter sometimes abbreviated as “unsaturated cyclic carbonate”), any cyclic carbonate having a carbon-carbon double bond or a carbon-carbon triple bond may be used. There is no limitation, 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 Examples include vinylene carbonate.

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

  Among these, particularly preferred unsaturated cyclic carbonates for use in combination with the diisocyanate compound represented by the general formula (1) and the cyclic carbonate having a fluorine atom include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl. Vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, allyl ethylene carbonate, 4 , 5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4, - diethynylfluorene ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate include 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 have 2 or more types by arbitrary combinations and ratios. 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.

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

Although it does not specifically limit 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, and potassium difluorophosphate. And lithium monofluorophosphate and lithium difluorophosphate are preferable, and lithium difluorophosphate is more preferable.

  Monofluorophosphate and difluorophosphate may be used alone 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.

<Compound having nitrile group>
The compound having a nitrile group is not particularly limited as long as it is a compound having a nitrile group in the molecule.
Specific examples of the compound having a nitrile group include, for example, acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclohexane. Pentanecarbonitrile, 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-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3 , 3′-oxydipropionitrile, 3,3′-thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, nitrile groups such as pentafluoropropionitrile A compound having one of the following:
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-dicarbonitrile, 2,5-dimethyl-2,5-hexanedicarbonitrile, 2,3-diisobutyl-2,3-dimethylsuccinonitrile, 2,2-diisobutyl-3,3-dimethylsuccino Nitrile, 2-methylglutaronitrile, 2,3-dimethylglutaronitrile, 2,4-dimethylglutaronitrile, 2,2,3,3-tetramethylglutaronitrile, 2,2,4,4-tetra Methylglutaronitrile, 2,2,3,4-tetramethylglutaronitrile, 2,3,3,4-tetramethylglutaronitrile, maleonitrile, fumaronitrile, 1,4-dicyanopentane, 2,6-dicyanoheptane 2,7-dicyanooctane, 2,8-dicyanononane, 1,6-dicyanodecane, 1,2-didiananobenzene, 1,3-disi Nobenzen, 1,4-dicyanobenzene, 3,3 '- (ethylenedioxy) dipropionate nitrile, 3,3' - (ethylene dithio) compound a nitrile group such as dipropionate nitrile having two;
Compounds having three nitrile groups such as 1,2,3-tris (2-cyanoethoxy) propane and tris (2-cyanoethyl) amine; methyl cyanate, ethyl cyanate, propyl cyanate, butyl cyanate, pentyl cyanate, hexyl cyanate, Cyanate compounds such as heptyl cyanate;
Methyl thiocyanate, ethyl thiocyanate, propyl thiocyanate, butyl thiocyanate, pentyl thiocyanate, hexyl thiocyanate, heptyl thiocyanate, methanesulfonyl cyanide, ethanesulfonyl cyanide, propanesulfonyl cyanide, butanesulfonyl cyanide, pentanesulfonyl cyanide, hexanesulfonyl cyanide , Heptanesulfonyl cyanide, methylsulfurocyanidate, ethylsulfurocyanidate, propylsulfurocyanidate, butylsulfurocyanidate, pentylsulfurocyanidate, hexylsulfurocyanidate, heptylsulfur Sulfur-containing compounds such as frocyanidates;
Cyanodimethylphosphine, cyanodimethylphosphine oxide, methyl cyanomethylphosphinate, methyl cyanomethylphosphinate, dimethylphosphinic acid cyanide, dimethylphosphinic acid cyanide, dimethyl phosphophosphonate, dimethyl cyanophosphonite, cyanomethyl methylphosphonate, methylphosphonite And phosphorus-containing compounds such as cyanomethyl acid, cyanodimethyl phosphate, and cyanodimethyl phosphite.

  Among these, lauronitrile, crotononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, and fumaronitrile are more 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 compound having a nitrile group may be used alone or in combination of two or more in any combination and ratio. The compounding amount of the compound having a nitrile group with respect to the whole non-aqueous electrolyte solution of the present invention is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. 001% by mass or more, 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. Let 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.

<Isocyanate compounds other than general formula (1)>
Specific examples of isocyanate compounds other than the general formula (1) include, for example, methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, tertiary butyl isocyanate, pentyl isocyanate hexyl isocyanate, cyclohexyl isocyanate, vinyl isocyanate, and allyl isocyanate. , Compounds having one isocyanate group such as ethynyl isocyanate, propynyl isocyanate, phenyl isocyanate, fluorophenyl isocyanate;
Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 1,3-diisocyanatopropane, 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-fluorohe Sun, 1,6-diisocyanato-3,4-difluorohexane, toluene diisocyanate, xylene diisocyanate, tolylene diisocyanate, dicyclohexylmethane-1,1'-diisocyanate, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-3, 3′-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, carbonyl diisocyanate, 1,4-diisocyanatobutane-1,4-dione, 1,5-diisocyanatopentane-1,5-dione, 2, And compounds having two isocyanate groups such as 2,4-trimethylhexamethylene diisocyanate and 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, dicyclohexylmethane Diisocyanate compounds such as -4,4'-diisocyanate, isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate are preferable from the viewpoint of improving storage characteristics.
The isocyanate compound other than the general formula (1) used in the present invention is a trimer compound derived from a compound having at least two isocyanate groups in the molecule, or an aliphatic polyisocyanate to which a polyhydric alcohol is added. There may be. Examples thereof include biuret, isocyanurate, adduct, and bifunctional type modified polyisocyanate represented by the basic structures of the following general formulas (3-1) to (3-4) (the following general formula (3-1) ) To (3-4), R and R ′ are each independently an arbitrary hydrocarbon group).

The compounds having an isocyanate group other than the general formula (1) used in the present invention include so-called blocked isocyanates which are 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.

  For the purpose of accelerating the reaction based on the compound having an isocyanate group other than the general formula (1) and obtaining 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.

  The compound which has an isocyanate group may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. There is no restriction | limiting in the compounding quantity of the compound which has an isocyanate group with respect to the whole nonaqueous electrolyte solution of this invention, Although it is arbitrary unless the effect of this invention is impaired remarkably, Usually, it is 0.8 with respect to the nonaqueous electrolyte solution of this invention. 001% by mass or more, 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. Let 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.

<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 inhibitor, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; 2-fluorobiphenyl, Partially fluorinated products of the above aromatic compounds such as o-cyclohexylfluorobenzene and p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like And a fluorine-containing anisole compound. 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 battery characteristics, 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. Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, anhydrous Carboxylic anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5 ] Spiro compounds such as undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, 1,3-propane sultone, 1-fluoro-1,3- Propane sultone, 2-fluoro-1,3-propane sultone, 3-ph Oro-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-butanesultone, 1-butene-1,4-sultone, 3-butene-1,4-sultone, methyl fluorosulfonate, ethyl fluorosulfonate, methanesulfonic acid Sulfur-containing compounds such as methyl, ethyl methanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2 -Piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-me Nitrogen-containing compounds such as Rusukushin'imido; heptane, octane, nonane, decane, hydrocarbon compounds cycloheptane, etc., fluorobenzene, difluorobenzene, hexafluorobenzene, fluorinated aromatic compounds such as benzotrifluoride, and the like. 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. .

  The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte battery according to the present invention. Specifically, the components of the non-aqueous electrolyte such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte is prepared from the substantially isolated one 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 used for the negative electrode is described below. 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.

<Negative electrode active material>
Examples of the negative electrode active material include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like.
As a carbonaceous material used as a 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 products or 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 “ Simple metals) and alloys or compounds containing these atoms (sometimes abbreviated as “specific metal elements”). 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.

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

  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 and / or tin metal simple substance, 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 abbreviated as “lithium titanium composite oxide”). 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. Those substituted with one element are also preferred.
The metal oxide is a lithium titanium composite oxide represented by the general formula (A). In the general formula (A), 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, It is preferable that 0 ≦ 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 general formula (A), 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 general 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), 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 plane) 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.).

(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, it is more preferably 60 cm ⁻¹ or less, particularly preferably 40 cm ⁻¹ or less.

  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 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 a 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) .

Moreover, said Raman 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 or less is more preferable, and 10 m ² · g ⁻¹ or less is particularly preferable.

  When the value of the BET specific surface area is in the above range, precipitation of lithium on the electrode surface can be suppressed, while 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 Okura Riken), preliminarily drying the sample at 350 ° C. for 15 minutes under nitrogen flow, Using a nitrogen helium mixed gas accurately prepared so that the value of the relative pressure is 0.3, the nitrogen adsorption BET one-point method by the gas flow method is used.

(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 the high current density charge / discharge characteristics are larger, the filling property is improved and the resistance between the particles can be suppressed as the circularity is larger, so that 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 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 preferred, and is preferably 2 g · cm ^-3 or less, more preferably 1.8 g · cm ^-3 or less, 1.6 g · cm ^-3 or less are particularly preferred. 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 a sieve having a mesh 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 instrument (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.

(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 molded body 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 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 the carbonaceous material particles with a scanning electron microscope. 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.

<Configuration and production method of negative electrode>
Any known method can be used for producing the 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 the 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 the nonaqueous electrolyte injection) / (thickness of the current collector)” 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 further 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, battery capacity can be secured and heat generation of the current collector during high current density charge / discharge can be suppressed.

(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 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, NBR (Acrylonitrile / butadiene rubber), rubbery polymers such as ethylene / propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof; EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene・ Thermoplastic elastomeric polymers such as butadiene / styrene copolymer, styrene / isoprene / styrene block copolymer 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. Fluoropolymers; polymer compositions having ionic conductivity of alkali metal ions (especially 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 more preferably 3% by mass or more. It is preferably 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 an organic solvent may be used.

  Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N- 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.

  Further, when using a thickener, 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, Moreover, it is 5 mass% or less normally, 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 converted 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. While the deterioration of the high current density charge / discharge characteristics due to the reduced permeability of the non-aqueous electrolyte solution can be suppressed, 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)
Moreover, you may use what adhered 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.

The transition metal of the lithium transition metal composite oxide is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu or the like, and specific examples include lithium / cobalt composite oxide such as LiCoO ₂ or LiNiO ₂ . Lithium / nickel composite oxides, 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, etc. And the like. Specific examples of the substituted ones include, 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.

  In addition, 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 lower limit of the amount of lithium phosphate used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.5% by mass with respect to the total of the positive electrode active material and lithium phosphate. %, And the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 5% by mass or less.

(Surface coating)
Moreover, you may use what the substance of the composition different from this adhered to the surface of the said positive electrode active material. 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 making carbon adhere, the method of making carbonaceous adhere mechanically later in the form of activated carbon etc. can also be used, for example.

  The amount of the surface adhering substance is by mass with respect to the positive electrode active material, preferably 0.1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more, and the upper limit, preferably 20% or less, more preferably, as the lower limit. Is used at 10% or less, more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material and can improve the battery life. However, when the amount of the adhering quantity is too small, the effect is not sufficiently manifested. If it is too high, the 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 in 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 positive electrode active material filling rate and 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 large 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 further 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 defined 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 measuring cylinder and tapped 200 times with a stroke of about 20 mm. Ask.

(Median diameter d50)
The median diameter d50 of the positive electrode active material particles (secondary particle diameter when primary particles aggregate to form secondary particles) is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably. Is 0.8 μm or more, most preferably 1.0 μm or more, and the upper limit is preferably 30 μm or less, more preferably 27 μm or less, still more 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 battery performance degradation can be suppressed. On the other hand, when producing a positive electrode for a battery, that is, when an active material, a conductive material, a binder, etc. 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, the filling property at the time of producing the positive electrode can be further improved.

  In the present invention, the median diameter d50 is measured by a known laser diffraction / scattering particle size distribution measuring device. 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. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more 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 and deterioration of battery performance can be suppressed, while reversibility of charge and 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 the upper limit is 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 determined by using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken), preliminarily drying the sample at 150 ° C. for 30 minutes under nitrogen flow, and then atmospheric pressure. It is defined by a value measured by a nitrogen adsorption BET one-point method using a gas flow method using a nitrogen-helium mixed gas accurately prepared so that the value of the relative pressure of nitrogen to 0.3 is 0.3.

(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 producing a spherical or elliptical active material. For example, a transition metal raw material is dissolved or ground and dispersed in a solvent such as water, and the pH is adjusted while stirring. And a spherical precursor is prepared and recovered, dried as necessary, and then a Li source such as LiOH, Li ₂ CO ₃ , LiNO _{3 and the} like is added and fired at a high temperature to obtain an active material. .

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. A preferable combination in this case is a combination of LiCoO ₂ and LiMn ₂ O ₄ such as LiNi _0.33 Co _0.33 Mn _0.33 O ₂ or a part of this Mn substituted with another transition metal or the like, or LiCoO ₂ or The combination with what substituted a part of Co with other transition metals etc. is mentioned.

<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 A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by applying it to a positive electrode current collector and drying it as a slurry by dissolving or dispersing in a slurry.

  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, an upper limit becomes like this. 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 as a lower limit, more preferably 2 g / cm ³ , further preferably 2.2 g / cm ³ or more, and preferably 5 g / cm ³ as an upper limit. ^{It is 3} or less, more preferably 4.5 g / cm ³ or less, and further preferably 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 a ratio. 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 in the positive electrode active material layer, and the upper limit is usually 50% by mass or less, preferably It is used so as to contain 30% by mass 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-like 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 soprene / 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 a polymer composition having ion conductivity. 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 the upper limit is usually 80% by mass or less, preferably Is 60% by mass or less, more preferably 40% by mass or less, and most preferably 10% by 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 an organic solvent may be used. Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of the organic medium 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 medium 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. The upper limit is 5% by mass or less, preferably 3% by mass or less, more preferably 2% by 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 the upper limit is usually 1 mm or less, preferably 100 μm or less. More preferably, it is 50 μm 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 The lower limit is preferably 15 or less, most preferably 10 or less, and the lower limit is 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 metal foil thickness of the core material is preferably as a lower limit with respect to one side of the current collector. Is 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

(Positive electrode surface coating)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said positive 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, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

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 properties 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, insulation and mechanical strength can be secured, while battery performance such as rate characteristics and energy density can be secured.

  Furthermore, when using a porous material such as a porous sheet or nonwoven fabric 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, Further, it is usually 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 secured, while film resistance can be suppressed and good rate characteristics can be obtained.

  Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. 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 the form, a thin film shape such as a non-woven 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 increases, the internal resistance increases. Therefore, it is also preferable to provide a plurality of terminals in the electrode to reduce the resistance. 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 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>
As a protective element, PTC (Positive Temperature Coefficient) whose resistance increases when abnormal heat generation or excessive current flows, temperature fuse, thermistor, shuts off the current flowing through the circuit due to sudden increase in battery internal pressure or internal temperature at 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.

<Example 1-1 and Comparative Examples 1-1 to 1-7 (Battery Evaluation)>
[Initial capacity evaluation]
A non-aqueous electrolyte battery produced by the method described later was charged at a constant current of up to 4.1 V with a current corresponding to 0.2 C at 25 ° C. in a state of being pressed between glass plates (hereinafter referred to as “CC”). The battery may be abbreviated as “charge”), discharged to 3 V at a constant current of 0.2 C (hereinafter sometimes abbreviated as “CC discharge”), and further regulated to 4.33 V at a current equivalent to 0.2 C. After current-constant voltage charging (hereinafter sometimes abbreviated as “CCCV charging”) (0.05 C cut), CC was discharged to 3 V at 0.2 C to stabilize the battery. Next, after CCCV charge (0.05 C cut) to 4.33 V at 0.2 C, CC discharge to 3 V at 0.5 C was performed to determine the initial capacity.
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.

[Cycle characteristic evaluation]
After the initial capacity evaluation, the non-aqueous electrolyte battery was charged with CCCV to 4.53 V at 0.5 C to 4.33 V, and then CC discharged to 3.0 V at 0.5 C as one cycle. Cycled. The discharge capacity retention ratio was calculated from the formula of (discharge capacity at the 70th cycle) ÷ (discharge capacity at the first cycle) × 100.

[High temperature storage characteristics evaluation]
After the initial capacity evaluation, the non-aqueous electrolyte battery was again charged with CCCV (0.05C cut) to 4.33V at 0.2C, and then stored at 85 ° C for 24 hours at a high temperature. It was. After the battery was sufficiently cooled, CC discharge was performed at 25 ° C. to 3 V at 0.2 C. After that, CCCV charge (0.05C cut) to 4.33V at 0.2C, CC discharge to 3V at 0.5C, 0.5C discharge capacity after high temperature storage characteristics test was measured, and this was stored at high temperature The later 0.5C recovery capacity was used. Again, CCCV charge (0.05 C cut) was performed up to 4.33 V, CC discharge was performed up to 3 V at 1 C, the 1 C discharge capacity after the high temperature storage characteristic test was measured, and this was defined as the 1 C recovery capacity after high temperature storage.

[Production of positive electrode]
94% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 3% by mass of acetylene black as a conductive material, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder, an N-methylpyrrolidone solvent The slurry was mixed 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 mass of natural graphite powder as a negative electrode active material, an aqueous dispersion of carboxymethylcellulose sodium (concentration of 1% by mass of carboxymethylcellulose sodium) and an aqueous dispersion of styrenebutadiene rubber (styrenebutadiene) as a thickener and a binder, respectively. A rubber concentration of 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. In addition, it produced so that it might become a mass ratio of natural graphite: carboxymethylcellulose sodium: styrene-butadiene rubber = 100: 1: 1 in the negative electrode after drying.

[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. This battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and a nonaqueous electrolyte solution described later was injected into the bag. Then, vacuum sealing was performed to produce a sheet-like non-aqueous electrolyte battery.

[Preparation of non-aqueous electrolyte]
In a dry argon atmosphere, the dried LiPF ₆ was dissolved in a mixture of monofluoroethylene carbonate (MFEC) and dimethyl carbonate (DMC) (volume ratio 30:70) to a ratio of 1 mol / L, and the basic electrolyte was dissolved. Prepared. The basic electrolyte solution was mixed with the compounds described in Table 1 to obtain electrolyte solutions used in Example 1-1 and Comparative Examples 1-1 to 1-3, respectively.
In a dry argon atmosphere, a basic electrolyte solution is prepared by dissolving LiPF ₆ dried in a mixture of ethylene carbonate (EC), DMC and vinylene carbonate (VC) (volume ratio 30: 70: 2) to a ratio of 1 mol / L. Was prepared. A compound was mixed with this basic electrolyte at a ratio shown in Table 1 (a ratio with respect to 100 parts by mass of the basic electrolyte) to obtain electrolytes used in Comparative Examples 1-4 to 1-7, respectively.

  Using this non-aqueous electrolyte battery, initial capacity evaluation, cycle characteristic evaluation, and high-temperature storage characteristic evaluation were performed. The evaluation results are shown in Table 1.

From Table 1, when the non-aqueous electrolyte solution of Example 1-1 according to the present invention is used, the diisocyanate compound represented by the general formula (1) is not added together with the cyclic carbonate having a fluorine atom (Comparative Example 1). It can be seen that the discharge capacity retention ratio and the recovery capacity after storage are excellent as compared to -1). In addition, when a diisocyanate compound not included in the general formula (1) is added (Comparative Examples 1-2 to 1-3), the discharge capacity retention ratio and the recovery capacity after storage cannot be improved at the same time. It turns out that it is insufficient.
Moreover, in the electrolyte solution which does not contain the cyclic carbonate which has a fluorine atom, when the diisocyanate compound represented by General formula (1) is added (Comparative Example 1-5), when not added (Comparative Example 1-4) ), The discharge capacity retention rate is reduced.
From this, by using a cyclic carbonate having a fluorine atom as a solvent and containing the diisocyanate compound represented by the general formula (1) in the nonaqueous electrolytic solution, a good composite film is formed on the negative electrode, In addition, the electrochemical side reaction on the positive and negative electrodes is specifically suppressed to suppress the capacity deterioration during storage at high temperature and the capacity deterioration during cycling, and has excellent charge / discharge characteristics under high current density. It can be seen that an aqueous electrolyte battery can be provided.

<Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-6 (Battery evaluation)>
[Rate characteristics evaluation]
A non-aqueous electrolyte battery (coin type) produced by the method described later was CC charged for 6 hours at 25 ° C. with a current corresponding to 0.05 C, and then CC discharged to 3.0 V at 0.2 C. Then, CC-CV charge (0.05C cut) was carried out to 4.1V with the electric current equivalent to 0.2C, and CC discharge was carried out to 3V with the constant current of 0.2C. Furthermore, after CC-CV charge (0.05C cut) to 4.33V with a current equivalent to 0.2C, CC discharge to 3V at 0.2C was repeated three times, and the discharge capacity for the third time was 0.2C. The capacity. Further, after CCCV charge (0.05C cut) to 4.33V at 0.2C, CC discharge to 3V at 0.5C to obtain 0.5C discharge capacity, the ratio of 0.5C discharge capacity to 0.2C capacity This was determined as the rate characteristic (%).

[Production of positive electrode]
94% by mass of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 3% by mass of acetylene black as a conductive material, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder, in an N-methylpyrrolidone solvent, The slurry was mixed with a disperser. This was uniformly applied to one side of an aluminum foil having a thickness of 21 μm, dried, and then pressed. Thereafter, it was punched into a disk shape having a diameter of 12.5 mm to obtain a positive electrode for a non-aqueous electrolyte battery (coin type).

[Production of negative electrode]
100 parts by mass of natural graphite powder as a negative electrode active material, an aqueous dispersion of carboxymethylcellulose sodium (concentration of 1% by mass of carboxymethylcellulose sodium) and an aqueous dispersion of styrenebutadiene rubber (styrenebutadiene) as a thickener and a binder, respectively. A rubber concentration of 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. Thereafter, it was punched into a disk shape having a diameter of 12.5 mm to obtain a negative electrode for a non-aqueous electrolyte battery (coin type). In addition, it produced so that it might become a mass ratio of natural graphite: carboxymethylcellulose sodium: styrene-butadiene rubber = 100: 1: 1 in the negative electrode after drying.

[Production of non-aqueous electrolyte battery (coin type)]
Using the above positive electrode and negative electrode and the non-aqueous electrolyte prepared in each Example and Comparative Example, a coin-type cell was produced by the following procedure. That is, the positive electrode was housed in a stainless steel can that also serves as the positive electrode conductor, and the negative electrode was placed thereon via a polyethylene separator impregnated with an electrolyte solution described later. The can body and a sealing plate serving also as a negative electrode conductor were caulked and sealed through an insulating gasket to produce a non-aqueous electrolyte battery (coin type).

[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, dried LiPF ₆ was dissolved in a mixture of EC and DMC (volume ratio 30:70) at a ratio of 1 mol / L to prepare a basic electrolyte. A compound is mixed with this basic electrolyte at a ratio shown in Table 2 (a ratio with respect to 100 parts by mass of the basic electrolyte) and used in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-6, respectively. An electrolyte was used.

  Rate characteristics were evaluated using this non-aqueous electrolyte battery (coin type). The evaluation results are shown in Table 2.

From Table 2, when the non-aqueous electrolyte solution of Examples 2-1 to 2-4 according to the present invention is used, the cyclic carbonate having a fluorine atom and the diisocyanate compound represented by the general formula (1) are not added. It can be seen that the rate characteristics are superior to (Comparative Example 2-1).
Moreover, when only the diisocyanate compound represented by General formula (1) is added (Comparative Example 2-2), it is inadequate because a rate characteristic falls.
Moreover, when only the cyclic carbonate which has a fluorine atom is added (Comparative Examples 2-3 to 2-6), although the improvement of a rate characteristic is seen, it is inferior to the result of Examples 2-1 to 2-4.
From this, by using the diisocyanate compound represented by the general formula (1) together with the cyclic carbonate having a fluorine atom as an additive in a non-aqueous electrolyte, a good composite film is formed on the negative electrode, and on the positive and negative electrodes. It can be seen that a non-aqueous electrolyte battery having an excellent charge / discharge characteristic under a high current density can be provided.

<Example 3-1 and Comparative Examples 3-1 to 3-2 (Battery Evaluation)>
[Initial capacity / rate characteristics evaluation]
A non-aqueous electrolyte battery produced by the method described below was CC charged for 4 hours at a current corresponding to 0.05 C in a thermostatic bath at 25 ° C., and then CC-CV charged (0.2. 05C cut). Then, CC discharge was carried out to 2.75V at 0.2C. Subsequently, CC-CV (0.05 C cut) was performed at 0.2 C to 4.0 V, and then CC discharge was performed at 0.2 C to 2.75 V, thereby stabilizing the non-aqueous electrolyte secondary battery. Then, after performing CC-CV charge (0.05C cut) to 4.2V at 0.2C, CC discharge was carried out to 2.75V at 0.2C, and this was made into the initial capacity. Furthermore, after CCCV charge (0.05 C cut) to 4.2 V at 0.2 C, CC discharge to 2.75 V at 0.5 C to obtain 0.5 C discharge capacity, 0.5 C discharge capacity relative to 0.2 C capacity Was the initial rate characteristic (%).

[Cycle characteristic evaluation]
The cell after the initial capacity evaluation was CCCV charged to 4.2 V at 0.2 C in a 45 ° C. thermostatic chamber, and then CC discharged to 2.75 V at a constant current of 0.2 C to obtain the discharge capacity of the first cycle. . Then, after CCCV charging to 4.2V at 0.5C, CC discharging to 2.75V with a constant current of 0.5C was performed as 200 cycles. Then, after CCCV charge to 4.2V at 0.2C, CC discharge to 2.75V was performed at 0.2C, and the discharge capacity at the 200th cycle was obtained. The discharge capacity retention ratio was calculated from the formula of (discharge capacity at 200th cycle) ÷ (discharge capacity at the first cycle) × 100.

[Post-cycle rate characteristics evaluation]
After the cycle characteristics evaluation, the cell was subjected to CC-CV charge (0.05C cut) to 0.2V at 0.2C in a 25 ° C constant temperature bath, and then CC discharged to 2.75V at 0.2C. The 0.2 C discharge capacity was then determined. Furthermore, after CCCV charge (0.05C cut) to 4.2V at 0.2C, CC discharge to 2.75V at 0.5C to obtain 0.5C discharge capacity after cycle, and cycle for 0.2C capacity after cycle The ratio of the post 0.5C discharge capacity was defined as the post cycle characteristic (%).

[Production of positive electrode]
94% by mass of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 3% by mass of acetylene black as a conductive material, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder, in an N-methylpyrrolidone solvent, The slurry was mixed with a disperser. This was uniformly applied to one side of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
A negative electrode active material, silicon powder, graphite powder, and a binder are mixed, and N-methylpyrrolidone is added to the binder to form a slurry. did.

[Preparation of non-aqueous electrolyte battery]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the positive electrode, the separator, the negative electrode, the separator, and the positive electrode to produce a battery element. This battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and a nonaqueous electrolyte solution described later was injected into the bag. Then, vacuum sealing was performed to produce a sheet-like non-aqueous electrolyte battery.

[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, 0.25% by mass of maleic anhydride is mixed with a mixture of MFEC and ethyl methyl carbonate (EMC) (volume ratio 20:80) as a content in the non-aqueous electrolyte, and then thoroughly dried. The basic electrolyte solution was prepared by dissolving LiPF ₆ so as to have a ratio of 1.0 mol / liter. A compound was mixed with the basic electrolyte at a ratio shown in Table 3 (a ratio with respect to 100 parts by mass of the basic electrolyte) to obtain electrolytes used in Example 3-1 and Comparative Examples 3-1 to 3-2, respectively. .

  Using this nonaqueous electrolyte battery, initial capacity / rate characteristic evaluation, cycle characteristic evaluation, and post-cycle rate characteristic evaluation were performed. The evaluation results are shown in Table 3.

From Table 3, when the non-aqueous electrolyte solution of Example 3-1 according to the present invention is used, the diisocyanate compound represented by the general formula (1) is not added together with the cyclic carbonate having a fluorine atom (Comparative Example 3). As compared with -1), it can be seen that the discharge capacity retention ratio and the initial / cycle rate characteristics are excellent. In addition, when a diisocyanate compound not included in the general formula (1) is added (Comparative Example 3-2), the discharge capacity retention ratio and the initial / cycle rate characteristics cannot be improved at the same time. It turns out that it is enough.
From this, by using a cyclic carbonate having a fluorine atom as a solvent and containing the diisocyanate compound represented by the general formula (1) in the nonaqueous electrolytic solution, a good composite film is formed on the negative electrode, In addition, the electrochemical side reaction on the positive and negative electrodes is specifically suppressed, capacity deterioration during storage at high temperature and capacity deterioration during cycling are suppressed, and non-aqueous system combines excellent charge / discharge characteristics under high current density An electrolyte battery can be provided.

According to the non-aqueous electrolyte of the present invention, non-aqueous electrolysis that has excellent charge / discharge characteristics under high current density while suppressing capacity deterioration during storage at high temperature and capacity deterioration during cycling of the non-aqueous electrolyte battery. A liquid battery can be provided. 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 (5)

A non-aqueous electrolyte comprising at least a lithium salt and a non-aqueous organic solvent, wherein the non-aqueous electrolyte comprises at least (A) a diisocyanate compound represented by the following general formula (1), and (B) a fluorine atom. A non-aqueous electrolyte containing a cyclic carbonate having

(In Formula (1), A is a C4-C15 organic group which has one C4-C6 cycloalkylene group.)   The cyclic carbonate having a fluorine atom is 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 1.   The non-aqueous electrolyte solution according to claim 1 or 2, wherein the diisocyanate compound represented by the general formula (1) is contained in an amount of 0.001 to 10% by mass in the non-aqueous electrolyte solution.   The non-aqueous electrolyte solution according to any one of claims 1 to 3, wherein the cyclic carbonate compound having a fluorine atom is contained in an amount of 0.1% by mass or more in the non-aqueous electrolyte solution.   5. A non-aqueous electrolyte battery comprising a negative electrode and a positive electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is a non-aqueous electrolyte solution according to claim 1. A non-aqueous electrolyte battery characterized by the above.