JP2011044255A - Nonaqueous electrolyte, and nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte which can prepare a battery having excellent safety and excellent durability and excellent charge and discharge characteristics of high capacity and high current density, and to provide the nonaqueous electrolyte battery produced by using the nonaqueous electrolyte. <P>SOLUTION: In the nonaqueous electrolyte for the nonaqueous electrolyte battery including an electrolyte and a nonaqueous solvent for dissolving the electrolyte, the nonaqueous electrolyte includes cyclic carbonate and a cyclic sulfone compound containing fluorine, the cyclic carbonate containing fluorine is 8-40 vol.% to the whole nonaqueous solvent, the total amount of a volume of the cyclic carbonate and a volume of the cyclic sulfone compound containing fluorine is 20-60 vol.% to the whole nonaqueous solvent. The nonaqueous electrolyte battery is produced by using the nonaqueous electrolyte. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  Non-aqueous electrolyte batteries such as lithium secondary batteries are being put to practical use in a wide range of applications from so-called consumer power sources such as mobile phones and notebook computers to in-vehicle power sources for automobiles and the like. However, the demand for higher performance of non-aqueous electrolyte batteries in recent years is increasing, and battery characteristics such as high capacity, high output, high temperature storage characteristics, cycle characteristics, and high safety are achieved at a high level. It is demanded.

  The electrolyte used for a non-aqueous electrolyte battery is usually composed mainly of an electrolyte and a non-aqueous solvent. As main components of the non-aqueous solvent, cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as gamma butyrolactone and gamma valerolactone are used. ing.

  In order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, etc. of these non-aqueous electrolyte batteries, and to improve battery safety during heating and short-circuiting, various studies on non-aqueous solvents and electrolytes Has been made. For example, among non-aqueous solvents, sulfolane has a higher boiling point than ethylene carbonate or propylene carbonate of 278 ° C. in addition to a relatively large dielectric constant and high electrochemical oxidation stability. It can be expected to contribute to the improvement of battery safety. However, the melting point of sulfolane is as high as 28 ° C., and the battery using sulfolane as a main solvent has a problem that the low temperature characteristics are deteriorated. It is also known that sulfolane has poor compatibility with the graphite negative electrode, and when used as a main solvent, the capacity during charge / discharge is smaller than the theoretical capacity.

  For example, Patent Document 1 discloses that in a non-aqueous electrolyte solution for a non-aqueous electrolyte secondary battery, the use of a mixed solvent of sulfolane and ethyl methyl carbonate prevents the electrolyte solution from solidifying at a low temperature. Yes. However, in the non-aqueous electrolyte secondary battery using this electrolyte, the reversibility of the electrode reaction in the initial charge / discharge is not sufficient, and thus the charge / discharge capacity and the charge / discharge efficiency cannot be satisfied.

  Patent Document 2 discloses that in a non-aqueous electrolyte solution for a non-aqueous electrolyte secondary battery, sulfolane and gamma butyrolactone are used as main solvents and vinyl ethylene carbonate and vinylene carbonate are added to the surface of the graphite negative electrode. It is disclosed that a high-quality coating with high lithium ion permeability is formed, and the initial charge / discharge efficiency is improved. However, in the non-aqueous electrolyte secondary battery using this electrolyte, the resistance due to the insertion / desorption reaction of lithium ions is increased in order to form a graphite negative electrode film with both vinylene carbonate and vinyl ethylene carbonate, There was a problem that output characteristics deteriorated.

  Under these circumstances, demands for higher performance of batteries in recent years are increasing, and to achieve high capacity, high output, high temperature storage characteristics, cycle characteristics, high safety, etc. at a higher level. Is required.

JP 2000-012078 A JP 2004-296389 A

  An object of the present invention is to provide a non-aqueous electrolyte that can achieve both high battery performance and high safety when a non-aqueous electrolyte containing a cyclic sulfone compound is used. The object is to provide an aqueous electrolyte battery.

  As a result of intensive studies to solve the above problems, the present inventors have used a cyclic carbonate containing fluorine together with a cyclic sulfone compound in a specific amount as a solvent for a non-aqueous electrolyte solution. The present inventors have found that high battery performance and high safety can be compatible while suppressing a decrease in charge / discharge characteristics with density, and the present invention has been completed.

  That is, the gist of the present invention is a non-aqueous electrolyte solution for a non-aqueous electrolyte battery containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, wherein the non-aqueous electrolyte solution includes a fluorine-containing cyclic carbonate and a cyclic sulfone compound. The volume of the cyclic carbonate containing fluorine is 8 to 40% by volume with respect to the whole non-aqueous solvent, and the total of the volume of the cyclic carbonate containing fluorine and the volume of the cyclic sulfone compound is The nonaqueous electrolyte solution is 20 to 60% by volume.

  The gist of the present invention is a non-aqueous electrolyte battery including 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 the non-aqueous electrolyte solution described above. It exists in the non-aqueous electrolyte battery characterized by this.

  In the non-aqueous electrolyte solution of the present invention, the volume ratio of the cyclic carbonate containing fluorine is 8 to 40% by volume with respect to the whole non-aqueous solvent, and the volume of the cyclic carbonate containing fluorine and the volume of the cyclic sulfone compound. Is a range of 20 to 60% by volume. If the total ratio of the volume of the cyclic carbonate containing fluorine and the volume of the cyclic sulfone compound is smaller than the above concentration range, ionic association is likely to occur because ion association is likely to occur, resulting in a decrease in output, On the other hand, when the concentration range is larger than the above range, the viscosity of the non-aqueous electrolyte increases, the ion mobility decreases, and the ionic conductivity decreases, so the output decreases. Thus, by selecting the concentration range, a high output derived from high ionic conductivity can be given, and in addition, safety derived from the cyclic sulfone compound can be maintained.

  In addition, both the cyclic carbonate containing fluorine and the cyclic sulfone compound are characterized by high electrochemical oxidation stability. Therefore, the battery should be operated at a higher temperature and higher voltage than conventional non-aqueous electrolytes. As a result, durability and output are improved.

  That is, according to the present invention, in addition to charge / discharge characteristics at a high capacity, a high voltage, and a high current density, a non-aqueous electrolyte battery that is remarkably superior in durability and safety compared to a general-purpose electrolyte is provided. In addition to increasing the size and performance of the non-aqueous electrolyte battery, higher safety can be achieved.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.

[1. Non-aqueous electrolyte]
The non-aqueous electrolyte solution of the present invention contains an electrolyte and a non-aqueous solvent that dissolves the electrolyte, as in the case of a conventional non-aqueous electrolyte solution, and usually contains these as the main components.

<1-1. Electrolyte>
As the electrolyte in 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,
Inorganic lithium salts such as LiPF ₆ and LiBF ₄ ;
LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethane disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , 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 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 ) fluorinated organic lithium salt such as ₂ ;
Examples thereof include lithium bis (oxalate) borate.

Of these, LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ or LiN (C ₂ F ₅ SO ₂ ) ₂ are preferable from the viewpoint of improving battery performance, and LiPF ₆ or LiBF ₄ is particularly preferable. preferable. These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using two or more types together is a combination of LiPF ₆ and LiBF ₄ , which has an effect of improving cycle characteristics. In this case, the proportion of LiBF _{4 in} the total of both is preferably 0.01% by mass or more, particularly preferably 0.1% by mass or more, preferably 20% by mass or less, particularly preferably 5% by mass. It is as follows. If the ratio of LiBF ₄ is 0.01% by mass or more, a desired effect is easily obtained, and if it is 20% by mass or less, good battery characteristics are easily maintained even after high-temperature storage.

Another example is the combined use of an inorganic lithium salt and a fluorine-containing organic lithium salt. In this case, the proportion of the inorganic lithium salt in the total of both is preferably 70% by mass or more, more preferably 99% by mass. % Or less. Examples of the fluorine-containing organic lithium salt include LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane. It is preferably any one of disulfonylimides. The combined use of both has the effect of suppressing deterioration due to high temperature storage.

  The concentration of the electrolyte in the nonaqueous electrolytic solution is not particularly limited, but is usually 0.5 mol / L or more, preferably 0.6 mol / L or more, more preferably 0.7 mol / L or more, and usually 3 mol / L. L or less, preferably 2 mol / L or less, more preferably 1.8 mol / L or less, particularly preferably 1.5 mol / L or less. If the concentration of the electrolyte is 0.5 mol / L or more, sufficient electric conductivity of the electrolytic solution is easily obtained, and if it is 3 mol / L or less, it is easy to avoid a decrease in electrical conductivity due to an increase in viscosity. Easy to maintain good battery performance.

<1-2. Cyclic sulfone compound>
The “cyclic sulfone compound” is not particularly limited as long as the cyclic part is a cyclic compound composed of a methylene group and a sulfonyl group (—S (═O) ₂ —), and any cyclic sulfone compound can be used. . The cyclic sulfone compound may optionally have a substituent. Among them, the cyclic moiety is preferably composed of 3 or more methylene groups and 1 or more sulfonyl groups, optionally having a substituent, and having a molecular weight of 500 or less.

  The methylene group at the cyclic site in the cyclic sulfone compound is preferably 3-6, and the sulfonyl group is preferably 1-2.

  Examples of the substituent include a halogen atom, an alkyl group, and an alkyl group substituted with a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom is mentioned, Preferably it is a fluorine atom or a chlorine atom, and a fluorine atom is especially preferable. As an alkyl group, a C1-C4 alkyl group is mentioned, 1-2 are preferable. Examples of the alkyl group substituted with a halogen atom include an alkyl group having 1 to 4 carbon atoms substituted with a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and preferably 1 to 2 carbon atoms. The number of substituents may be one or plural, and preferably 1 to 3 from the viewpoint of the effect of the present invention.

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

  As the cyclic sulfone compound, sulfolane and / or sulfolane derivatives (hereinafter sometimes abbreviated as “sulfolanes” including sulfolane) are preferable in that the effects of the present invention can be easily obtained. As the sulfolane derivative, a sulfolane derivative in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with a halogen atom is particularly preferable. Moreover, as a sulfolane derivative, what has an alkyl group can also be used, and the hydrogen atom couple | bonded with the carbon atom which comprises an alkyl group may be substituted by the halogen atom.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom or a chlorine atom is preferable, and a fluorine atom is particularly preferable. When this is a substituent on a carbon atom constituting a sulfolane ring, it is a substituent of an alkyl group bonded to the sulfolane ring. Applies to both.

As a sulfolane derivative containing an alkyl group as a substituent of the sulfolane ring,
2-methylsulfolane,
3-methylsulfolane,
2,2-dimethylsulfolane,
3,3-dimethylsulfolane,
2,3-dimethylsulfolane,
2,4-dimethylsulfolane,
2,5-dimethylsulfolane,
2,2,3-trimethylsulfolane,
2,2,4-trimethylsulfolane,
2,2,5-trimethylsulfolane,
2,3,3-trimethylsulfolane,
3,3,4-trimethylsulfolane,
3,3,5-trimethylsulfolane,
2,3,4-trimethylsulfolane,
2,3,5-trimethylsulfolane,
2,2,3,3-tetramethylsulfolane,
2,2,3,4-tetramethylsulfolane,
2,2,3,5-tetramethylsulfolane,
2,2,4,4-tetramethylsulfolane,
2,2,4,5-tetramethylsulfolane,
2,2,5,5-tetramethylsulfolane,
2,3,3,4-tetramethylsulfolane,
2,3,3,5-tetramethylsulfolane,
2,3,4,4-tetramethylsulfolane,
2,3,4,5-tetramethylsulfolane,
3,3,4,4-tetramethylsulfolane,
2,2,3,3,4-pentamethylsulfolane,
2,2,3,3,5-pentamethylsulfolane,
2,2,3,4,4-pentamethylsulfolane,
2,2,3,4,5-pentamethylsulfolane,
2,3,3,4,4-pentamethylsulfolane,
2,3,3,4,5-pentamethylsulfolane,
2,2,3,3,4,4-hexamethylsulfolane,
2,2,3,3,4,5-hexamethylsulfolane,
2,2,3,3,5,5-hexamethylsulfolane,
2,2,3,4,5,5-hexamethylsulfolane,
2,2,3,3,4,4,5-heptamethylsulfolane,
2,2,3,3,4,5,5-heptamethylsulfolane,
And octamethylsulfolane.

As a sulfolane ring substituent, a sulfolane derivative containing a fluorine atom,
2-fluorosulfolane,
3-fluorosulfolane,
2,2-difluorosulfolane,
2,3-difluorosulfolane,
2,4-difluorosulfolane,
2,5-difluorosulfolane,
3,4-difluorosulfolane,
2,2,3-trifluorosulfolane,
2,3,3-trifluorosulfolane,
2,2,4-trifluorosulfolane,
2,2,5-trifluorosulfolane,
2,3,4-trifluorosulfolane,
2,3,5-trifluorosulfolane,
2,4,4-trifluorosulfolane,
2,2,3,3-tetrafluorosulfolane,
2,2,3,4-tetrafluorosulfolane,
2,2,4,4-tetrafluorosulfolane,
2,2,5,5-tetrafluorosulfolane,
2,3,3,4-tetrafluorosulfolane,
2,3,3,5-tetrafluorosulfolane,
2,3,4,4-tetrafluorosulfolane,
2,3,4,5-tetrafluorosulfolane,
2,2,3,3,4-pentafluorosulfolane,
2,2,3,3,5-pentafluorosulfolane,
2,2,3,4,4-pentafluorosulfolane,
2,2,3,4,5-pentafluorosulfolane,
2,3,3,4,4-pentafluorosulfolane,
2,3,3,4,5-pentafluorosulfolane,
2,2,3,3,4,4-hexafluorosulfolane,
2,2,3,3,4,5-hexafluorosulfolane,
2,2,3,3,5,5-hexafluorosulfolane,
2,2,3,4,5,5-hexafluorosulfolane,
2,2,3,3,4,4,5-heptafluorosulfolane,
2,2,3,3,4,5,5-heptafluorosulfolane,
And octafluorosulfolane.

As a sulfolane derivative having an alkyl group and a fluorine atom as a substituent of the sulfolane ring,
2-fluoro-3-methylsulfolane,
2-fluoro-2-methylsulfolane,
3-fluoro-3-methylsulfolane,
3-fluoro-2-methylsulfolane,
4-fluoro-3-methylsulfolane,
4-fluoro-2-methylsulfolane,
5-fluoro-3-methylsulfolane,
5-fluoro-2-methylsulfolane,
2-fluoro-2,4-dimethylsulfolane,
4-fluoro-2,4-dimethylsulfolane,
5-fluoro-2,4-dimethylsulfolane,
2,2-difluoro-3-methylsulfolane,
2,3-difluoro-3-methylsulfolane,
2,4-difluoro-3-methylsulfolane,
2,5-difluoro-3-methylsulfolane,
3,4-difluoro-3-methylsulfolane,
3,5-difluoro-3-methylsulfolane,
4,4-difluoro-3-methylsulfolane,
4,5-difluoro-3-methylsulfolane,
5,5-difluoro-3-methylsulfolane,
2,2,3-trifluoro-3-methylsulfolane,
2,2,4-trifluoro-3-methylsulfolane,
2,2,5-trifluoro-3-methylsulfolane,
2,3,4-trifluoro-3-methylsulfolane,
2,3,5-trifluoro-3-methylsulfolane,
2,4,4-trifluoro-3-methylsulfolane,
2,4,5-trifluoro-3-methylsulfolane,
2,5,5-trifluoro-3-methylsulfolane,
3,4,4-trifluoro-3-methylsulfolane,
3,4,5-trifluoro-3-methylsulfolane,
4,4,5-trifluoro-3-methylsulfolane,
4,5,5-trifluoro-3-methylsulfolane,
2,2,3,4-tetrafluoro-3methylsulfolane,
2,2,3,5-tetrafluoro-3-methylsulfolane,
2,2,4,4-tetrafluoro-3-methylsulfolane,
2,2,4,5-tetrafluoro-3-methylsulfolane,
2,2,5,5-tetrafluoro-3-methylsulfolane,
2,3,4,4-tetrafluoro-3-methylsulfolane,
2,3,4,5-tetrafluoro-3-methylsulfolane,
2,3,5,5-tetrafluoro-3-methylsulfolane,
3,4,4,5-tetrafluoro-3-methylsulfolane,
3,4,5,5-tetrafluoro-3-methylsulfolane,
4,4,5,5-tetrafluoro-3-methylsulfolane,
2,2,3,4,4-pentafluoro-3-methylsulfolane,
2,2,3,4,5-pentafluoro-3-methylsulfolane,
2,2,3,5,5-pentafluoro-3-methylsulfolane,
2,3,4,4,5-pentafluoro-3-methylsulfolane,
2,3,4,5,5-pentafluoro-3-methylsulfolane,
2,2,3,4,4,5-hexafluoro-3-methylsulfolane,
2,2,3,4,5,5-hexafluoro-3-methylsulfolane,
2,3,4,4,5,5-hexafluoro-3-methylsulfolane,
Heptafluoro-3-methylsulfolane, and the like.

As a sulfolane derivative having a monofluoroalkyl group and a fluorine atom as a substituent of the sulfolane ring,
2-fluoromethylsulfolane 3-fluoromethylsulfolane 2-fluoro-3- (fluoromethyl) sulfolane,
3-fluoro-3- (fluoromethyl) sulfolane,
4-fluoro-3- (fluoromethyl) sulfolane,
5-fluoro-3- (fluoromethyl) sulfolane,
2,2-difluoro-3- (fluoromethyl) sulfolane,
2,3-difluoro-3- (fluoromethyl) sulfolane,
2,4-difluoro-3- (fluoromethyl) sulfolane,
2,5-difluoro-3- (fluoromethyl) sulfolane,
3,4-difluoro-3- (fluoromethyl) sulfolane,
3,5-difluoro-3- (fluoromethyl) sulfolane,
4,4-difluoro-3- (fluoromethyl) sulfolane,
4,5-difluoro-3- (fluoromethyl) sulfolane,
5,5-difluoro-3- (fluoromethyl) sulfolane,
2,2,3-trifluoro-3- (fluoromethyl) sulfolane,
2,2,4-trifluoro-3- (fluoromethyl) sulfolane,
2,2,5-trifluoro-3- (fluoromethyl) sulfolane,
2,3,4-trifluoro-3- (fluoromethyl) sulfolane,
2,3,5-trifluoro-3- (fluoromethyl) sulfolane,
2,4,4-trifluoro-3- (fluoromethyl) sulfolane,
2,4,5-trifluoro-3- (fluoromethyl) sulfolane,
2,5,5-trifluoro-3- (fluoromethyl) sulfolane,
3,4,4-trifluoro-3- (fluoromethyl) sulfolane,
3,4,5-trifluoro-3- (fluoromethyl) sulfolane,
4,4,5-trifluoro-3- (fluoromethyl) sulfolane,
4,5,5-trifluoro-3- (fluoromethyl) sulfolane,
2,2,3,4-tetrafluoro-3- (fluoromethyl) sulfolane,
2,2,3,5-tetrafluoro-3- (fluoromethyl) sulfolane,
2,2,4,4-tetrafluoro-3- (fluoromethyl) sulfolane,
2,2,4,5-tetrafluoro-3- (fluoromethyl) sulfolane,
2,2,5,5-tetrafluoro-3- (fluoromethyl) sulfolane,
2,3,4,4-tetrafluoro-3- (fluoromethyl) sulfolane,
2,3,4,5-tetrafluoro-3- (fluoromethyl) sulfolane,
2,3,5,5-tetrafluoro-3- (fluoromethyl) sulfolane,
3,4,4,5-tetrafluoro-3- (fluoromethyl) sulfolane,
3,4,5,5-tetrafluoro-3- (fluoromethyl) sulfolane,
4,4,5,5-tetrafluoro-3- (fluoromethyl) sulfolane,
2,2,3,4,4-pentafluoro-3- (fluoromethyl) sulfolane,
2,2,3,4,5-pentafluoro-3- (fluoromethyl) sulfolane,
2,2,3,5,5-pentafluoro-3- (fluoromethyl) sulfolane,
2,3,4,4,5-pentafluoro-3- (fluoromethyl) sulfolane,
2,3,4,5,5-pentafluoro-3- (fluoromethyl) sulfolane,
2,2,3,4,4,5-hexafluoro-3- (fluoromethyl) sulfolane,
2,2,3,4,5,5-hexafluoro-3- (fluoromethyl) sulfolane,
2,3,4,4,5,5-hexafluoro-3- (fluoromethyl) sulfolane,
And heptafluoro-3- (fluoromethyl) sulfolane.

As a sulfolane derivative having a difluoroalkyl substituent and a fluorine atom as a substituent of the sulfolane ring,
2-difluoromethylsulfolane 3-difluoromethylsulfolane 2-fluoro-3- (difluoromethyl) sulfolane,
3-fluoro-3- (difluoromethyl) sulfolane,
4-fluoro-3- (difluoromethyl) sulfolane,
5-fluoro-3- (difluoromethyl) sulfolane,
2,2-difluoro-3- (difluoromethyl) sulfolane,
2,3-difluoro-3- (difluoromethyl) sulfolane,
2,4-difluoro-3- (difluoromethyl) sulfolane,
2,5-difluoro-3- (difluoromethyl) sulfolane,
3,4-difluoro-3- (difluoromethyl) sulfolane,
3,5-difluoro-3- (difluoromethyl) sulfolane,
4,4-difluoro-3- (difluoromethyl) sulfolane,
4,5-difluoro-3- (difluoromethyl) sulfolane,
5,5-difluoro-3- (difluoromethyl) sulfolane,
2,2,3-trifluoro-3- (difluoromethyl) sulfolane,
2,2,4-trifluoro-3- (difluoromethyl) sulfolane,
2,2,5-trifluoro-3- (difluoromethyl) sulfolane,
2,3,4-trifluoro-3- (difluoromethyl) sulfolane,
2,3,5-trifluoro-3- (difluoromethyl) sulfolane,
2,4,4-trifluoro-3- (difluoromethyl) sulfolane,
2,4,5-trifluoro-3- (difluoromethyl) sulfolane,
2,5,5-trifluoro-3- (difluoromethyl) sulfolane,
3,4,4-trifluoro-3- (difluoromethyl) sulfolane,
3,4,5-trifluoro-3- (difluoromethyl) sulfolane,
4,4,5-trifluoro-3- (difluoromethyl) sulfolane,
4,5,5-trifluoro-3- (difluoromethyl) sulfolane,
2,2,3,4-tetrafluoro-3- (difluoromethyl) sulfolane,
2,2,3,5-tetrafluoro-3- (difluoromethyl) sulfolane,
2,2,4,4-tetrafluoro-3- (difluoromethyl) sulfolane,
2,2,4,5-tetrafluoro-3- (difluoromethyl) sulfolane,
2,2,5,5-tetrafluoro-3- (difluoromethyl) sulfolane,
2,3,4,4-tetrafluoro-3- (difluoromethyl) sulfolane,
2,3,4,5-tetrafluoro-3- (difluoromethyl) sulfolane,
2,3,5,5-tetrafluoro-3- (difluoromethyl) sulfolane,
3,4,4,5-tetrafluoro-3- (difluoromethyl) sulfolane,
3,4,5,5-tetrafluoro-3- (difluoromethyl) sulfolane,
4,4,5,5-tetrafluoro-3- (difluoromethyl) sulfolane,
2,2,3,4,4-pentafluoro-3- (difluoromethyl) sulfolane,
2,2,3,4,5-pentafluoro-3- (difluoromethyl) sulfolane,
2,2,3,5,5-pentafluoro-3- (difluoromethyl) sulfolane,
2,3,4,4,5-pentafluoro-3- (difluoromethyl) sulfolane,
2,3,4,5,5-pentafluoro-3- (difluoromethyl) sulfolane,
2,2,3,4,4,5-hexafluoro-3- (difluoromethyl) sulfolane,
2,2,3,4,5,5-hexafluoro-3- (difluoromethyl) sulfolane,
2,3,4,4,5,5-hexafluoro-3- (difluoromethyl) sulfolane,
And heptafluoro-3- (difluoromethyl) sulfolane.

As a sulfolane ring substituent, a sulfolane derivative having a trifluoroalkyl substituent and a fluorine atom,
2-trifluoromethyl sulfolane 3-trifluoromethyl sulfolane 2-fluoro-3- (trifluoromethyl) sulfolane,
3-fluoro-3- (trifluoromethyl) sulfolane,
4-fluoro-3- (trifluoromethyl) sulfolane,
5-fluoro-3- (trifluoromethyl) sulfolane,
2,2-difluoro-3- (trifluoromethyl) sulfolane,
2,3-difluoro-3- (trifluoromethyl) sulfolane,
2,4-difluoro-3- (trifluoromethyl) sulfolane,
2,5-difluoro-3- (trifluoromethyl) sulfolane,
3,4-difluoro-3- (trifluoromethyl) sulfolane,
3,5-difluoro-3- (trifluoromethyl) sulfolane,
4,4-difluoro-3- (trifluoromethyl) sulfolane,
4,5-difluoro-3- (trifluoromethyl) sulfolane,
5,5-difluoro-3- (trifluoromethyl) sulfolane,
2,2,3-trifluoro-3- (trifluoromethyl) sulfolane,
2,2,4-trifluoro-3- (trifluoromethyl) sulfolane,
2,2,5-trifluoro-3- (trifluoromethyl) sulfolane,
2,3,4-trifluoro-3- (trifluoromethyl) sulfolane,
2,3,5-trifluoro-3- (trifluoromethyl) sulfolane,
2,4,4-trifluoro-3- (trifluoromethyl) sulfolane,
2,4,5-trifluoro-3- (trifluoromethyl) sulfolane,
2,5,5-trifluoro-3- (trifluoromethyl) sulfolane,
3,4,4-trifluoro-3- (trifluoromethyl) sulfolane,
3,4,5-trifluoro-3- (trifluoromethyl) sulfolane,
4,4,5-trifluoro-3- (trifluoromethyl) sulfolane,
4,5,5-trifluoro-3- (trifluoromethyl) sulfolane,
2,2,3,4-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,2,3,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,2,4,4-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,2,4,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,2,5,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,3,4,4-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,3,4,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,3,5,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
3,4,4,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
3,4,5,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
4,4,5,5-tetrafluoro-3- (trifluoromethyl) sulfolane,
2,2,3,4,4-pentafluoro-3- (trifluoromethyl) sulfolane,
2,2,3,4,5-pentafluoro-3- (trifluoromethyl) sulfolane,
2,2,3,5,5-pentafluoro-3- (trifluoromethyl) sulfolane,
2,3,4,4,5-pentafluoro-3- (trifluoromethyl) sulfolane,
2,3,4,5,5-pentafluoro-3- (trifluoromethyl) sulfolane,
2,2,3,4,4,5-hexafluoro-3- (trifluoromethyl) sulfolane,
2,2,3,4,5,5-hexafluoro-3- (trifluoromethyl) sulfolane,
2,3,4,4,5,5-hexafluoro-3- (trifluoromethyl) sulfolane,
And heptafluoro-3- (trifluoromethyl) sulfolane.

Among the sulfolanes mentioned above,
Sulfolane,
2-methylsulfolane,
3-methylsulfolane,
2,2-dimethylsulfolane,
3,3-dimethylsulfolane,
2,3-dimethylsulfolane,
2,4-dimethylsulfolane,
2,5-dimethylsulfolane,
2-fluorosulfolane,
3-fluorosulfolane,
2-fluoro-3-methylsulfolane,
3-fluoro-3-methylsulfolane,
4-fluoro-3-methylsulfolane,
5-fluoro-3-methylsulfolane,
2-fluoro-2-methylsulfolane,
3-fluoro-2-methylsulfolane,
4-fluoro-2-methylsulfolane,
5-fluoro-2-methylsulfolane,
2-fluoro-2,4-dimethylsulfolane,
3-fluoro-2,4-dimethylsulfolane,
4-fluoro-2,4-dimethylsulfolane,
5-fluoro-2,4-dimethylsulfolane,
2-fluoromethylsulfolane,
3-fluoromethylsulfolane,
2-difluoromethylsulfolane,
3-difluoromethylsulfolane,
2-trifluoromethylsulfolane,
3-Trifluoromethylsulfolane is more preferred.

Particularly preferably,
Sulfolane,
2-methylsulfolane,
3-methylsulfolane,
2-fluorosulfolane,
3-fluorosulfolane,
2-fluoro-3-methylsulfolane,
3-fluoro-3-methylsulfolane,
4-fluoro-3-methylsulfolane,
5-fluoro-3-methylsulfolane,
2-fluoromethylsulfolane,
3-fluoromethylsulfolane,
2-difluoromethylsulfolane,
3-difluoromethylsulfolane,
2-trifluoromethylsulfolane,
3-trifluoromethylsulfolane.

  In addition, when an excessively alkyl-substituted cyclic sulfone compound is used, the viscosity is increased, and it is easy to cause a decrease in electrical conductivity. When an excessively fluorinated cyclic sulfone compound is used, a non-aqueous electrolyte battery is obtained. The alkyl group is preferably 3 or less and the fluorine atom is 8 or less because it tends to cause a decrease in chemical stability and solubility in other solvents when used. preferable.

  One kind of the cyclic sulfone compound may be contained alone in the nonaqueous electrolytic solution of the present invention, or two or more kinds thereof may be used in combination in any combination and ratio. Moreover, there is no restriction | limiting in particular also in a manufacturing method, It is possible to manufacture by selecting a well-known method arbitrarily.

  In the non-aqueous electrolyte solution of the present invention, the cyclic sulfone compound can be 5% by volume or more, preferably 10% by volume or more, more preferably 20% by volume with respect to the entire non-aqueous solvent (100% by volume). In addition, it can be 50% by volume or less, preferably 40% by volume or less, more preferably 35% by volume or less. Below the lower limit of this range, when the non-aqueous electrolyte solution of the present invention is used in a non-aqueous electrolyte battery, the non-aqueous electrolyte battery may not easily exhibit a sufficient safety improvement effect. Exceeding the upper limit of this range tends to cause a decrease in electrical conductivity due to an increase in the viscosity of the non-aqueous electrolyte, especially when charging / discharging a non-aqueous electrolyte battery at a high current density. In addition, the charge / discharge capacity retention rate may be reduced.

<1-3. Cyclic carbonate containing fluorine>
The cyclic carbonate containing fluorine (hereinafter sometimes abbreviated as “fluorinated cyclic carbonate”) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.

  The number of fluorine atoms contained in the fluorinated cyclic carbonate is not particularly limited as long as it is 1 or more, but is preferably 10 or less, more preferably 8 or less.

  Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is 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 these fluorinated cyclic carbonates, selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate At least one compound is more preferable in that it provides high ionic conductivity and suitably forms an interface protective film.

  As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes abbreviated as “fluorinated unsaturated cyclic carbonate”). There is no restriction | limiting in particular as a fluorinated unsaturated cyclic carbonate. Of these, those having 1 or 2 fluorine atoms are preferred.

  Examples of the fluorinated unsaturated cyclic carbonate include vinylene carbonate derivatives, ethylene carbonate derivatives substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond, and the like.

  Examples of the vinylene carbonate derivative include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4,5-difluoroethylene carbonate, and the like.

  Examples of the ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4,4-difluoro-4. -Vinylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4-fluoro-4-phenyl Examples include ethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4-phenylethylene carbonate, and the like.

  The molecular weight of the fluorinated cyclic carbonate is not particularly limited, and preferably 50 or more, more preferably 80 or more, and preferably 250 or less, more preferably 150 or less. When the molecular weight is 250 or less, the solubility of the fluorinated cyclic carbonate in the nonaqueous electrolytic solution is good, and the effects of the present invention are easily exhibited. Moreover, there is no restriction | limiting in particular also in the manufacturing method of a fluorinated cyclic carbonate, It is possible to select and manufacture a well-known method arbitrarily.

  Any one of the fluorinated cyclic carbonates may be contained alone in the nonaqueous electrolytic solution of the present invention, or two or more of them may be contained in any combination and ratio. A fluorinated cyclic carbonate is 8-40 volume% with respect to the whole nonaqueous solvent (100 volume%) in the nonaqueous electrolyte solution of this invention. Below the lower limit of this range, when the non-aqueous electrolyte of the present invention is used in a non-aqueous electrolyte battery, the non-aqueous electrolyte battery exhibits a sufficient ion conductivity improvement effect and cycle characteristic improvement effect. If the ratio of the fluorinated cyclic carbonate is too large, when the non-aqueous electrolyte of the present invention is used in a non-aqueous electrolyte battery, the high-temperature storage characteristics of the non-aqueous electrolyte battery deteriorate. In particular, there are cases where the amount of gas generation increases and the discharge capacity retention rate decreases. The fluorinated cyclic carbonate is preferably 10% by volume or more, preferably 35% by volume or less, more preferably 30% by volume or less with respect to the entire nonaqueous solvent (100% by volume).

<1-4. "Chain carbonate">
The non-aqueous electrolyte of the present invention can further contain a chain carbonate.

  The chain carbonate is preferably one having 3 to 7 carbon atoms, and examples thereof include dialkyl carbonates having 3 to 7 carbon atoms. Here, the two alkyl groups may be the same or different.

  Examples of the chain carbonate having 3 to 7 carbon atoms include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, and n-butyl methyl. Examples include carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate, and the like.

  Among these, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl-n-propyl carbonate are preferable.

  Among these, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable.

  Further, a chain carbonate 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 preferably 6 or less, more preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be the same as or different from each other.

  Examples of the fluorinated chain carbonate include a fluorinated product of a chain carbonate having 3 to 7 carbon atoms, such as a dimethyl carbonate derivative, an ethylmethyl carbonate derivative, and a diethyl carbonate derivative.

  Examples of the dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoro) methyl carbonate, and the like.

  Examples of the ethyl methyl carbonate derivative include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trifluoroethyl. Examples include methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Diethyl carbonate 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, 2,2,2- Examples thereof include trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

  Any one of the chain carbonates may be contained alone in the non-aqueous electrolyte solution of the present invention, or two or more thereof may be used in combination in any combination and ratio.

  In the present invention, the chain carbonate is preferably 30% by volume or more, more preferably 40% by volume or more, and still more preferably 50% by volume or more with respect to the entire non-aqueous solvent (100% by volume) in the non-aqueous electrolyte solution. It is. Below this lower limit, there is a tendency to cause a decrease in electrical conductivity resulting from an increase in the viscosity of the non-aqueous electrolyte, and in particular, the large current discharge characteristics of the non-aqueous electrolyte battery may be reduced. The chain carbonate is preferably 80% by volume or less, more preferably 75% by volume or less, and still more preferably 70% by volume or less. Above this range, there is a tendency to cause a decrease in electrical conductivity due to a decrease in the dielectric constant of the nonaqueous electrolyte of the present invention, and in particular, the large current discharge characteristics of a nonaqueous electrolyte battery may be reduced. is there.

<1-5. Cyclic carbonate and / or cyclic carboxylic acid ester compound>
The non-aqueous electrolyte solution of the present invention can contain a cyclic carbonate and / or a cyclic carboxylic acid ester. Cyclic carbonates and / or cyclic carboxylic acid esters are preferred in that the electrical conductivity is improved. The cyclic carbonate does not include a cyclic carbonate containing fluorine.

  Examples of the cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms.

  Examples of the chain carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, butylene carbonate and the like. Among these, ethylene carbonate and propylene carbonate are preferable from the viewpoint of improving battery characteristics, and ethylene carbonate is particularly preferable.

  Examples of the cyclic carboxylic acid ester include lactone compounds having 3 to 12 carbon atoms, and examples thereof include gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone, and the like. Among them, gamma butyrolactone, gamma valerolactone and the like are preferable, and gamma tyrolactone is particularly preferable from the viewpoint of improving battery characteristics.

  In the present invention, the cyclic carbonate and / or the cyclic carboxylic acid ester is preferably 5% by volume or more, more preferably 10% by volume or more with respect to the entire non-aqueous solvent (100% by volume) in the non-aqueous electrolyte solution. . Below this lower limit, there is little increase in electrical conductivity with respect to the non-aqueous electrolyte solution of the present invention, and in particular, it may not contribute to the improvement of the large current discharge characteristics of the non-aqueous electrolyte battery. The cyclic carbonate and / or cyclic carboxylic acid ester is preferably 40% by volume or less, more preferably 35% by volume or less. Above this range, there is a tendency to cause a decrease in electrical conductivity resulting from an increase in the viscosity of the non-aqueous electrolyte, and in particular, the large current discharge characteristics of the non-aqueous electrolyte battery may be reduced.

  The cyclic carbonate and / or the cyclic carboxylic acid ester may be contained alone in the non-aqueous electrolyte solution of the present invention, or two or more kinds may be used in combination in any combination and ratio. Also good.

<1-6. Preferred combinations of non-aqueous solvents>
One preferred combination of non-aqueous solvents is a combination containing sulfolanes, a fluorinated cyclic carbonate, and a chain carbonate. Among them, the total of sulfolanes, fluorinated cyclic carbonates and chain carbonates is preferably 40% by volume or more, more preferably 50% by volume or more, and still more preferably 60% with respect to the entire nonaqueous solvent (100% by volume). When a combination of non-aqueous solvents that is at least volume%, preferably at most 95 volume%, more preferably at most 90 volume% is used, the large current discharge characteristics and safety of a battery produced using this combination are improved. This is preferable because the balance is improved.

  Another preferred combination is a combination containing sulfolanes, a fluorinated cyclic carbonate and a cyclic carbonate. Among them, the total of sulfolane, fluorinated cyclic carbonate and cyclic carbonate is preferably more than 20% by volume, more preferably 25% by volume or more, and further preferably 30% by volume with respect to the entire nonaqueous solvent (100% by volume). In addition, when a combination of nonaqueous solvents that is preferably 60% by volume or less, more preferably 50% by volume or less, and even more preferably 45% by volume or less is used, cycle characteristics of a battery manufactured using the same And a large current discharge characteristic are preferable.

  Other preferred combinations include combinations containing sulfolanes, fluorinated cyclic carbonates and cyclic carboxylic acid esters. Among them, the total of sulfolanes, fluorinated cyclic carbonate, and cyclic carboxylic acid ester is preferably more than 20% by volume, more preferably 25% by volume or more, and still more preferably based on the whole non-aqueous solvent (100% by volume). 30% by volume or more, and preferably 60% by volume or less, more preferably 50% by volume or less, and even more preferably 45% by volume or less of a non-aqueous solvent combination. This is preferable because the balance between high current discharge characteristics and safety is improved.

  Other preferred combinations include combinations containing sulfolanes, fluorinated cyclic carbonates, chain carbonates, cyclic carbonates and / or cyclic carboxylic acid esters. Among them, the total of sulfolanes, fluorinated cyclic carbonate, chain carbonate, cyclic carbonate and / or cyclic carboxylic acid ester is preferably 60% by volume or more, more preferably, based on the entire nonaqueous solvent (100% by volume). Is a balance of high current charge / discharge characteristics, safety, high voltage resistance and cycle characteristics of a battery produced using a combination of non-aqueous solvents of 70 volume% or more, more preferably 80 volume% or more. Is preferable.

  In this specification, the volume of the non-aqueous solvent is a measured value at 25 ° C., but the measured value at the melting point is used for a solid at 25 ° C. such as ethylene carbonate.

<1-7. Other compounds>
The nonaqueous electrolytic solution of the present invention can contain “other compounds” as long as the effects of the present invention are not impaired. Examples of such “other compounds” include various compounds such as conventionally known film forming agents, overcharge inhibitors, and auxiliary agents.

<1-7-1. Film forming agent>
By containing a film-forming agent, a high-quality film with high lithium ion permeability can be formed, and the initial charge and discharge efficiency can be improved. As a typical example, a carbonate having an unsaturated bond (hereinafter referred to as the following) May be abbreviated as “unsaturated carbonate”).

  The unsaturated carbonate is not particularly limited as long as it is a carbonate having a carbon-carbon unsaturated bond such as a carbon-carbon double bond or a carbon-carbon triple bond, and any unsaturated carbonate can be used. In addition, the carbonate which has an aromatic ring shall also be contained in the carbonate which has an unsaturated bond.

  Examples of the unsaturated carbonate include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond, phenyl carbonates, vinyl carbonates, allyl carbonates, and the like.

  Examples of vinylene carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate and the like.

  Examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, phenyl ethylene carbonate, 4,5-diphenyl ethylene carbonate, and the like. .

  Examples of phenyl carbonates include diphenyl carbonate, ethyl phenyl carbonate, methyl phenyl carbonate, and t-butyl phenyl carbonate.

  Examples of vinyl carbonates include divinyl carbonate and methyl vinyl carbonate.

  Examples of allyl carbonates include diallyl carbonate and allyl methyl carbonate.

  Among these unsaturated carbonates, vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond are preferable, and in particular, vinylene carbonate, 4,5-diphenyl vinylene carbonate, 4, Since 5-dimethyl vinylene carbonate and vinyl ethylene carbonate form a stable interface protective film, they are more preferably used.

  The unsaturated carbonate is not particularly limited in molecular weight, and is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 50 or more, preferably 80 or more, and usually 250 or less, preferably 150 or less. If the molecular weight is too large, the solubility of the unsaturated carbonate in the non-aqueous electrolyte is lowered, and the effects of the present invention may not be sufficiently exhibited. Moreover, there is no restriction | limiting in particular also in the manufacturing method of unsaturated carbonate, It is possible to select and manufacture a well-known method arbitrarily.

  The unsaturated carbonate may be contained alone in the non-aqueous electrolyte solution of the present invention, or may be contained in combination of two or more in any combination and ratio. Moreover, there is no restriction | limiting in the compounding quantity of the unsaturated carbonate with respect to the whole non-aqueous 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 non-aqueous electrolyte solution of this invention. 01% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and usually 8% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. . Below the lower limit of this range, when the non-aqueous electrolyte of the present invention is used in a non-aqueous electrolyte battery, the non-aqueous electrolyte battery may not be able to exhibit a sufficient cycle characteristic improving effect. If the ratio of unsaturated carbonate is too large, when the non-aqueous electrolyte of the present invention is used in a non-aqueous electrolyte battery, the high-temperature storage characteristics of the non-aqueous electrolyte battery tend to be reduced. The amount generated may increase and the discharge capacity retention rate may decrease.

<1-7-2. Monofluorophosphate and Difluorophosphate>
Other film forming agents include monofluorophosphate and difluorophosphate. There is no particular restriction on the counter cation monofluorophosphate and difluorophosphate, Li, Na, K, Mg , Ca, Fe, other metal elements such as ^{Cu, NR 1 R 2 R 3 R} 4 ( formula Among them, R ^{1 to} R ⁴ each independently represents a hydrogen atom or an ammonium or quaternary ammonium represented by an organic group having 1 to 12 carbon atoms. Here, as the organic group having 1 to 12 carbon atoms of R ^{1 to} R ⁴ , an alkyl group which may be substituted with a halogen atom, a cycloalkyl group which may be substituted with a halogen atom, or a halogen atom An aryl group, a nitrogen atom-containing heterocyclic group, and the like, which may be used. R ^{1 to} R ⁴ are each preferably a hydrogen atom, an alkyl group, a cycloalkyl group, a nitrogen atom-containing heterocyclic group, or the like.

Among these counter cations, lithium, sodium, potassium, magnesium, calcium or NR ¹ R ² R ³ R ⁴ is preferable, and lithium is particularly preferable from the viewpoint of battery characteristics when used in a lithium secondary battery.

  Among monofluorophosphates and difluorophosphates, difluorophosphate is preferable in terms of the effect of improving low-temperature discharge characteristics as well as battery cycle characteristics and high-temperature storage characteristics, and particularly lithium difluorophosphate. Particularly preferred. These compounds synthesized in a non-aqueous solvent may be used as they are, or those synthesized separately and substantially isolated are added in a non-aqueous solvent or a non-aqueous electrolyte. May be.

  There is no limit to the amount of “monofluorophosphate and / or difluorophosphate” added to the entire non-aqueous electrolyte of the present invention, and any amount can be used as long as the effects of the present invention are not significantly impaired. It is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 8% by mass or less, preferably 5% by mass or less, based on the electrolytic solution. More preferably, it is 3 mass% or less. When the amount is too large, the battery characteristics may be deteriorated by precipitation at a low temperature. On the other hand, when the amount is too small, the effect of improving the low-temperature characteristics, cycle characteristics, high-temperature storage characteristics, etc. may be significantly reduced.

<1-7-3. Overcharge prevention agent>
By containing an overcharge preventing agent, rupture / ignition of the battery can be suppressed during overcharge or the like.

  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, partially hydrogenated terphenyl, 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 types are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated product, cyclohexylbenzene, t-butylbenzene In combination with 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 and dibenzofuran, overcharge prevention characteristics and high temperature storage It is preferable from the viewpoint of balance of characteristics.

  The ratio of the overcharge inhibitor in the non-aqueous electrolyte is usually 0.1% by mass or more, preferably 0.2% by mass or more, particularly preferably 0.3% by mass or more, based on the whole non-aqueous electrolyte. Most preferably, it is 0.5 mass% or more, and is usually 5 mass% or less, preferably 3 mass% or less, and particularly preferably 2 mass% or less. When the concentration is lower than this lower limit, the effect of the overcharge inhibitor hardly appears. On the other hand, if the concentration is too high, battery characteristics such as high-temperature storage characteristics tend to deteriorate.

<1-8. Auxiliary>
As auxiliary agents, carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride Carboxylic anhydrides such as diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5] undecane Spiro compounds such as 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, 1,3-propane sultone, 1,4-butane sultone, methyl methanesulfonate , Ethyl methanesulfonate, busulfan, sulfole , Sulfur-containing compounds such as dimethylsulfone, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl- Nitrogen-containing compounds such as 2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide; hydrocarbon compounds such as heptane, octane, nonane, decane and cycloheptane, fluorobenzene, difluorobenzene, And fluorine-containing aromatic compounds such as hexafluorobenzene and benzotrifluoride. These may be used alone or in combination of two or more.

  The ratio of the auxiliary agent in the non-aqueous electrolyte is usually 0.01% by mass or more, preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, based on the whole non-aqueous electrolyte. Moreover, it is 5 mass% or less normally, Preferably it is 3 mass% or less, Most preferably, it is 1 mass% or less. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved. When the concentration is lower than this lower limit, the effect of the auxiliary agent hardly appears. Conversely, if the concentration is too high, battery characteristics such as high-load discharge characteristics tend to deteriorate.

<1-9. Preparation of non-aqueous electrolyte solution>
The nonaqueous electrolytic solution according to the present invention dissolves an electrolyte, a cyclic sulfone compound, a fluorinated cyclic carbonate, and optionally a chain carbonate, a cyclic carbonate, a cyclic carboxylic acid ester, and, if necessary, other compounds. Can be prepared. In preparing the non-aqueous electrolyte solution, each raw material is preferably dehydrated in advance in order to reduce the water content when the electrolyte solution is used. Usually, it is good to dehydrate to 50 ppm or less, preferably 30 ppm or less, particularly preferably 10 ppm or less. Moreover, you may implement dehydration, a deoxidation process, etc. after electrolyte solution preparation.

  The non-aqueous electrolyte solution of the present invention is suitable for use as an electrolyte solution for secondary batteries, for example, lithium secondary batteries, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the electrolytic solution of the present invention will be described.

[2. Non-aqueous electrolyte battery]
The non-aqueous electrolyte battery of the present invention includes a negative electrode and a positive electrode capable of occluding and releasing ions (for example, lithium ions), and the non-aqueous electrolyte of the present invention.

<2-1. Battery configuration>
The battery configuration of the non-aqueous electrolyte battery of the present invention is the same as that conventionally known. Usually, the positive electrode, the negative electrode, and the negative electrode are interposed through a porous film (separator) impregnated with the non-aqueous electrolyte of the present invention. Are stacked and these are housed in a case (exterior body). Therefore, the shape of the nonaqueous electrolyte battery of the present invention is not particularly limited, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

<2-2. Non-aqueous electrolyte>
As the non-aqueous electrolyte, the above-described non-aqueous electrolyte of the present invention is used. It should be noted that other non-aqueous electrolytes can be mixed with the non-aqueous electrolyte of the present invention without departing from the spirit of the present invention.

<2-3. 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 thereof include carbonaceous materials, alloy-based materials, lithium-containing metal composite oxide materials, and the like.

<2-3-1. Carbonaceous material>
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 of 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.

  The carbonizable organic substance includes coal tar pitch from soft pitch to hard pitch, heavy coal oil such as dry distillation liquefied oil, normal pressure residual oil, DC heavy oil of reduced pressure residual oil, crude oil Decomposed petroleum heavy oil such as ethylene tar by-produced during thermal decomposition of naphtha, aromatic hydrocarbons such as acenaphthylene, decacyclene, anthracene, phenanthrene, nitrogen atom-containing heterocyclic compounds such as phenazine, acridine, thiophene, bithiophene Sulfur atom-containing heterocyclic compounds such as, polyphenylene such as biphenyl and terphenyl, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, insolubilized products of these, organic polymers such as nitrogen-containing polyacrylonitrile and polypyrrole , Organic polymers such as sulfur-containing polythiophene and polystyrene, cellulose Heat of natural polymers such as lignin, mannan, polygalacturonic acid, chitosan, polysaccharides such as sucrose, thermoplastic resins such as polyphenylene sulfide and polyphenylene oxide, furfuryl alcohol resin, phenol-formaldehyde resin, imide resin Examples thereof include curable resins.

<2-3-2. Configuration, physical properties, preparation method of carbonaceous negative electrode>
About the property about a carbonaceous material, the negative electrode containing a carbonaceous material, an electrode-izing method, a collector, and a nonaqueous electrolyte battery, any one or a plurality of items (1) to (21) shown below It is desirable to satisfy

(1) X-ray parameters The d-value (interlayer distance) of the lattice plane (002 plane) obtained by X-ray diffraction by the Gakushin method of carbonaceous materials is preferably 0.335 nm or more. It is 360 nm or less, preferably 0.350 nm or less, and more preferably 0.345 nm or less. 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.

(2) Ash content The ash content in the carbonaceous material is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less, based on the total mass of the carbonaceous material. It is preferably 1 ppm or more.

  If the mass ratio of ash exceeds the above range, deterioration of battery performance due to reaction with the non-aqueous electrolyte during charge / discharge may not be negligible. On the other hand, if it falls below the above range, the production requires a lot of time, energy and equipment for preventing contamination, which may increase the cost.

(3) Volume-based average particle diameter 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. It is more preferably 5 μm or more, particularly preferably 7 μm or more, and usually 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 25 μm or less.

  If the volume-based average particle size is below the above range, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, when the above range is exceeded, when an electrode is produced by coating, an uneven coating surface tends to be formed, which may be undesirable in the battery production process.

  The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20) sorbitan monolaurate, which is a surfactant, and laser diffraction / scattering particle size distribution. This is carried out using a meter (LA-700 manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material of the present invention.

(4) Raman R value, Raman half value width The Raman R value of the carbonaceous material is a value measured by using an argon ion laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, 0 .1 or more is more preferable, and is usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, and particularly preferably 0.5 or less.

  When the Raman R value is below the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge / discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.

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

  If the Raman half width is less than the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge and discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.

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, calculates the intensity _{I A} of the peak PA around 1580 cm ^-1, and measuring the intensity _{I B} of a peak PB around 1360 cm ^-1, the intensity ratio R of the _{(R =} I B / _{I A)} To do. The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material of the present invention. Further, the half width of the peak P _A in the vicinity of 1580 cm ^-1 of the resulting Raman spectrum was measured, which is defined as the Raman half-value width of the carbonaceous material of the present invention.

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

(5) BET specific surface area The BET specific surface area of a carbonaceous material is the value of the specific surface area measured using the BET method, and is usually 0.1 m ² · g ⁻¹ or more, and 0.7 m ² · g ^−1. The above is preferable, 1.0 m ² · g ⁻¹ or more is more preferable, 1.5 m ² · g ⁻¹ or more is particularly preferable, and usually 100 m ² · g ⁻¹ or less, and 25 m ² · g ⁻¹ or less. Is preferably 15 m ² · g ⁻¹ or less, more preferably 10 m ² · g ⁻¹ or less.

  When the value of the BET specific surface area is less than this range, the acceptability of lithium is likely to deteriorate during charging when used as a negative electrode material, lithium is likely to precipitate on the electrode surface, and stability may be reduced. On the other hand, if it exceeds this range, when used as a negative electrode material, the reactivity with the non-aqueous electrolyte increases, gas generation tends to increase, and a preferable battery may be difficult to obtain.

  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 adjusted so that the value of the relative pressure becomes 0.3, the nitrogen adsorption BET one-point method by the gas flow method is used. The specific surface area determined by the measurement is defined as the BET specific surface area of the carbonaceous material of the present invention.

(6) Pore size distribution The pore size distribution of the carbonaceous material is calculated by measuring the mercury intrusion amount. When using a mercury porosimetry (mercury intrusion method) to measure voids in particles of carbonaceous material, irregularities due to steps on the surface of the particles, and pores due to contact surfaces between the particles, the diameter is 0.01 μm or more and 1 μm or less measurement of those corresponding to the pores, typically 0.01 cm ³ · ^{g -1} or more, preferably 0.05 cm ³ · ^{g -1} or more, more preferably 0.1 cm ³ · ^{g -1} or more, and usually It is desirable to have a pore size distribution of 0.6 cm ³ · g ⁻¹ or less, preferably 0.4 cm ³ · g ⁻¹ or less, more preferably 0.3 cm ³ · g ⁻¹ or less.

  If the pore size distribution exceeds the above range, a large amount of binder may be required when forming an electrode plate. On the other hand, if it falls below the above range, the high current density charge / discharge characteristics may be deteriorated, and the effect of relaxing the expansion and contraction of the electrode during charge / discharge may not be obtained.

Further, the total pore volume, which is obtained by mercury porosimetry (mercury intrusion method) and corresponds to pores having a diameter of 0.01 μm or more and 100 μm or less, is usually 0.1 cm ³ · g ⁻¹ or more, and 25 cm ³ · ^{g -1} or more, more preferably 0.4 cm ³ · ^{g -1} or higher, and is generally 10 cm ³ · ^{g -1} or less, preferably ^{5 cm} 3 · ^{g -1} or less, ^{2 cm} 3 · g ^-1 or less is more preferable.

  If the total pore volume exceeds the above range, a large amount of binder may be required when forming an electrode plate. On the other hand, if the amount is below the above range, the effect of dispersing the thickener or the binder may not be obtained when forming the electrode plate.

  The average pore diameter is usually 0.05 μm or more, preferably 0.1 μm or more, more preferably 0.5 μm or more, and usually 50 μm or less, preferably 20 μm or less, more preferably 10 μm or less.

  If the average pore diameter exceeds the above range, a large amount of binder may be required. Moreover, when it is less than the above range, the high current density charge / discharge characteristics may deteriorate.

  The mercury intrusion is measured using a mercury porosimeter (Autopore 9520: manufactured by Micromeritex Corporation) as an apparatus for mercury porosimetry. As a pretreatment, about 0.2 g of a sample is sealed in a powder cell and deaerated for 10 minutes at room temperature under vacuum (50 μmHg or less). Subsequently, the pressure is reduced to 4 psia (about 28 kPa), mercury is introduced, the pressure is increased stepwise from 4 psia (about 28 kPa) to 40000 psia (about 280 MPa), and then the pressure is reduced to 25 psia (about 170 kPa). The number of steps at the time of pressure increase is 80 points or more, and the mercury intrusion amount is measured after an equilibration time of 10 seconds in each step.

The pore size distribution is calculated from the mercury intrusion curve thus obtained using the Washburn equation. Note that the surface tension (γ) of mercury is 485 dyne · cm ⁻¹ ( ¹ dyne = 10 μN), and the contact angle (ψ) is 140 °. As the average pore diameter, the pore diameter when the cumulative pore volume is 50% is used.

(7) Circularity When the circularity is measured as a spherical degree 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. High current density charge / discharge characteristics improve as the degree of circularity increases. Therefore, when the circularity is less than the above range, the filling property of the negative electrode active material is lowered, the resistance between particles is increased, and the high current density charge / discharge characteristics may be lowered for a short time.

  The circularity is measured using a flow type particle image analyzer (FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample was dispersed in a 0.2% by mass aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate as a surfactant, and irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. The detection range is specified as 0.6 to 400 μm, and the particle size is measured in the range of 3 to 40 μm. The circularity determined by the measurement is defined as the circularity of the carbonaceous material of the present invention.

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

True density of (8) True Density carbonaceous material is usually 1.4 g · ^{cm -3} or higher, preferably 1.6 g · ^{cm -3} or more, more preferably 1.8 g · ^{cm -3} or more, 2. 0 g · ^{cm -3} or more are particularly preferred, also, usually less than 2.26 g · ^{cm -3.} When the true density is below the above range, the crystallinity of carbon is too low, and the initial irreversible capacity may increase. The upper limit of the above range is the theoretical upper limit of the true density of graphite.

  The true density of the carbonaceous material is measured by a liquid phase substitution method (pycnometer method) using butanol. The value obtained by the measurement is defined as the true density of the carbonaceous material of the present invention.

(9) 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 is particularly preferable, 2 g · cm ⁻³ or less is preferable, 1.8 g · cm ⁻³ or less is more preferable, and 1.6 g · cm ⁻³ or less is particularly preferable. When the tap density is below the above range, the packing density is difficult to increase when used as a negative electrode, and a high-capacity battery may not be obtained. On the other hand, when the above range is exceeded, there are too few voids between particles in the electrode, it is difficult to ensure conductivity between the particles, and it may be difficult to obtain preferable battery characteristics.

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

(10) 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 below the above range, the high-density charge / discharge characteristics may deteriorate. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

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

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

(11) 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. If the aspect ratio exceeds the above range, streaking or a uniform coated surface cannot be obtained when forming an electrode plate, and the high current density charge / discharge characteristics may deteriorate. 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. The aspect ratio (A / B) obtained by the measurement is defined as the aspect ratio of the carbonaceous material of the present invention.

(12) Secondary material mixing The secondary material mixing is to contain two or more carbonaceous materials having different properties in the negative electrode and / or the negative electrode active material. The properties referred to here are selected from the group consisting of X-ray diffraction parameters, median diameter, aspect ratio, BET specific surface area, orientation ratio, Raman R value, tap density, true density, pore distribution, circularity, and ash content. Shows more than one characteristic.

  Particularly preferred examples of mixing these materials are that the volume-based particle size distribution is not symmetrical when the median diameter is the center, that two or more carbonaceous materials having different Raman R values are contained, and X The line parameters are different.

  As an example of the effect of the auxiliary material mixing, it is possible to include as a conductive material a carbonaceous material such as natural graphite, graphite such as artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke. Thus, the electric resistance can be reduced.

  When mixing a conductive material as a secondary material mixture, one type may be mixed alone, or two or more types may be mixed in any combination and ratio. The mixing ratio of the conductive material to the carbonaceous material is usually preferably 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and usually 45% by mass or less. 40% by mass is preferred. If the mixing ratio is less than the above range, it may be difficult to obtain the effect of improving conductivity. On the other hand, exceeding the above range may increase the initial irreversible capacity.

(13) Electrode production Any known method can be used for the production of 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 a negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can do.

  The thickness of the negative electrode active material layer per side in the stage immediately before the non-aqueous electrolyte injection process of the battery is usually 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and usually 150 μm or less. 120 μm or less is preferable, and 100 μm or less is more preferable. If the thickness of the negative electrode active material exceeds this range, the non-aqueous electrolyte solution hardly penetrates to the vicinity of the current collector interface, and thus the high current density charge / discharge characteristics may be deteriorated. On the other hand, below this range, the volume ratio of the current collector to the negative electrode active material increases, and the battery capacity may decrease. The negative electrode active material may be formed into a sheet electrode by roll molding, or may be formed into a pellet electrode by compression molding.

(14) Current collector As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as 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.

  In addition, when the thickness of the copper foil is less than 25 μm, a copper alloy (phosphor bronze, titanium copper, Corson alloy, Cu—Cr—Zr alloy, etc.) having higher strength than pure copper can be used. A current collector made of a copper foil produced by a rolling method is suitable for use in a small cylindrical battery because the copper crystals are arranged in the rolling direction so that the negative electrode is hard to crack even if it is rounded sharply or rounded at an acute angle. be able to.

  Electrolytic copper foil, for example, immerses a metal drum in a non-aqueous electrolyte solution in which copper ions are dissolved, and causes the copper to precipitate on the surface of the drum by flowing current while rotating it. Is obtained. Copper may be deposited on the surface of the rolled copper foil by an electrolytic method. One side or both sides of the copper foil may be subjected to a roughening treatment or a surface treatment (for example, a chromate treatment having a thickness of about several nm to 1 μm, a base treatment such as Ti).

  The following physical properties are desired for the current collector substrate.

(14-1) Average surface roughness (Ra)
The average surface roughness (Ra) of the negative electrode active material thin film forming surface of the current collector substrate defined by the method described in JIS B0601-1994 is not particularly limited, but is usually 0.05 μm or more and 0.1 μm or more. Preferably, it is 0.15 μm or more, usually 1.5 μm or less, preferably 1.3 μm or less, more preferably 1.0 μm or less.

  When the average surface roughness (Ra) of the current collector substrate is within the above range, good charge / discharge cycle characteristics can be expected. Further, the area of the interface with the negative electrode active material thin film is increased, and the adhesion with the negative electrode active material thin film is improved. The upper limit value of the average surface roughness (Ra) is not particularly limited, but those having an average surface roughness (Ra) exceeding 1.5 μm are generally available as foils having a practical thickness as a battery. Since it is difficult, those of 1.5 μm or less are usually used.

(14-2) Tensile strength The tensile strength is obtained by dividing the maximum tensile force required until the test piece breaks by the cross-sectional area of the test piece. The tensile strength in the present invention is measured by the same apparatus and method as described in JISZ2241 (metal material tensile test method).

The tensile strength of the current collector substrate is not particularly limited, is usually 100 N · ^{mm -2} or more, preferably 250 N · ^{mm -2} or more, more preferably 400 N · ^{mm -2} or more, 500 N · ^{mm -2} or more Particularly preferred. The tensile strength is preferably as high as possible, but is usually 1000 N · mm ⁻² or less from the viewpoint of industrial availability. If the current collector substrate has a high tensile strength, cracking of the current collector substrate due to expansion / contraction of the negative electrode active material thin film accompanying charging / discharging can be suppressed, and good cycle characteristics can be obtained.

(14-3) 0.2% proof stress 0.2% proof stress is the magnitude of a load required to give a plastic (permanent) strain of 0.2%. It means that 0.2% deformation even when loaded. The 0.2% yield strength is measured with the same equipment and method as the tensile strength.

0.2% proof stress of the current collector substrate is not particularly limited, normally 30 N · ^{mm -2} or more, preferably 150 N · ^{mm -2} or more, particularly preferably 300N · ^{mm -2} or more. The 0.2% resistance value is preferably as high as possible, but 900 N · mm ⁻² or less is usually desirable from the viewpoint of industrial availability. If the current collector substrate has a high 0.2% proof stress, plastic deformation of the current collector substrate due to expansion / contraction of the negative electrode active material thin film accompanying charging / discharging can be suppressed, and good cycle characteristics can be obtained. Can do.

(14-4) Thickness of the metal thin film Although the thickness of the metal thin film is arbitrary, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less. 30 μm or less is more preferable. If the thickness of the metal film is less than 1 μm, the strength may be reduced, making application difficult. Moreover, when it becomes thicker than 100 micrometers, the shape of electrodes, such as winding, may be changed. The metal thin film may be mesh.

(15) Ratio of thickness of current collector and negative electrode active material layer The ratio of the thickness of current collector and negative electrode active material layer is not particularly limited, but “((1) negative electrode active material on one side immediately before non-aqueous electrolyte injection) The value of “layer thickness) / (current collector thickness)” is preferably 150 or less, more preferably 20 or less, particularly preferably 10 or less, preferably 0.1 or more, and more preferably 0.4 or more. One or more is preferable and particularly preferable. When the ratio of the thickness of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge / discharge. On the other hand, below the above range, the volume ratio of the current collector to the negative electrode active material increases, and the battery capacity may decrease.

(16) Electrode density The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · ^{cm -3} or more, and particularly preferably 1.3 g · ^{cm -3} or more, and preferably 2 g · ^{cm -3} or less, more preferably 1.9 g · ^{cm -3} or less, 1.8 g · cm ^{- 3} or less is more preferable, and 1.7 g · cm ⁻³ or less is particularly preferable. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases or non-aqueous system near the current collector / negative electrode active material interface. There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability of the electrolytic solution. On the other hand, if the amount is less than the above range, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume may decrease.

(17) 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 and the solvent used during electrode production.

  Specific examples include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, 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 copolymers or hydrogenated products thereof; EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / Thermoplastic elastomeric polymer such as butadiene / styrene copolymer, styrene / isoprene / styrene block copolymer or hydrogenated product thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene Soft resinous polymers such as vinyl acetate copolymer and propylene / α-olefin copolymer; Fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene / ethylene copolymer Polymers: Polymer compositions having ionic conductivity of alkali metal ions (particularly lithium ions), and the like. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  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, dimethylacetamide, 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.

  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 with respect to a negative electrode active material exceeds the said range, the binder ratio from which the amount of binders does not contribute to battery capacity may increase, and the fall of battery capacity may be caused. On the other hand, below the above range, the strength of the negative electrode may be reduced.

  In particular, when the main component contains a rubbery polymer typified by SBR, 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.

  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 less than the above range, applicability may be significantly reduced. Moreover, when it exceeds the said range, the ratio of the negative electrode active material which occupies for a negative electrode active material layer will fall, and the problem that the capacity | capacitance of a battery falls and the resistance between negative electrode active materials may increase.

(18) Electrode orientation ratio The electrode orientation ratio is usually 0.001 or more, preferably 0.005 or more, more preferably 0.01 or more, and usually 0.67 or less. When the electrode plate orientation ratio is below the above range, the high-density charge / discharge characteristics may be deteriorated. The upper limit of the above range is the theoretical upper limit of the electrode plate orientation ratio of the carbonaceous material.

  The electrode plate orientation ratio is measured by measuring the orientation ratio of the negative electrode active material of the electrode by X-ray diffraction for the negative electrode after being pressed to the target density. Although a specific method is not particularly limited, as a standard method, peak separation is performed by fitting peaks of carbon (110) diffraction and (004) diffraction by X-ray diffraction using asymmetric Pearson VII as a profile function. The integrated intensities of the peaks of (110) diffraction and (004) diffraction are calculated. From the obtained integrated intensity, a ratio represented by (110) diffraction integrated intensity / (004) diffraction integrated intensity is calculated. The electrode negative electrode active material orientation ratio calculated by the measurement is defined as the electrode plate orientation ratio of the carbonaceous material of the present invention.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
-Target: Cu (Kα ray) graphite monochromator-Slit: Divergence slit = 1 degree, Receiving slit = 0.1 mm, Scattering slit = 1 degree-Measurement range and step angle / measurement time:
(110) plane: 76.5 degrees ≦ 2θ ≦ 78.5 degrees 0.01 degrees / 3 seconds (004) plane: 53.5 degrees ≦ 2θ ≦ 56.0 degrees 0.01 degrees / 3 seconds Sample preparation: Fix the electrode to the glass plate with double-sided tape with a thickness of 0.1 mm

(19) Impedance The resistance of the negative electrode when charged from the discharged state to 60% of the nominal capacity is preferably 100Ω or less, more preferably 50Ω or less, particularly preferably 20Ω or less, and / or the double layer capacity is 1 × 10 ^{−. 6} F or more is preferable, 1 × 10 ⁻⁵ F or more is more preferable, and 1 × 10 ⁻⁴ F is particularly preferable. When the negative electrode in the above range is used, the output characteristics are good and preferable.

  The negative electrode resistance and double layer capacity are measured by charging the non-aqueous electrolyte battery to be measured at a current value at which the nominal capacity can be charged in 5 hours, and then maintaining the state without charge / discharge for 20 minutes, and then nominally. A capacitor whose capacity is 80% or more of the nominal capacity when discharged at a current value that can be discharged in one hour is used.

  About the non-aqueous electrolyte battery in the above discharge state, the nominal capacity is charged to 60% of the nominal capacity at a current value that can be charged in 5 hours, and the non-aqueous electrolyte battery is immediately transferred into a glove box under an argon gas atmosphere. . Here, the non-aqueous electrolyte battery is quickly disassembled and taken out in a state where the negative electrode is not discharged or short-circuited, and if it is a double-sided coated electrode, the negative electrode active material on one side is peeled off without damaging the negative electrode active material on the other side, Two negative electrodes are punched into 12.5 mmφ, and are opposed to each other so that the negative electrode active material surface does not shift through a separator. 60μL of non-aqueous electrolyte used in the battery was dropped between the separator and both negative electrodes, and kept in close contact with the outside air, and the current collector of both negative electrodes was made conductive and the AC impedance method was carried out. To do.

The measurement is performed at a temperature of 25 ° C., and a complex impedance measurement is performed in a frequency band of 10 ⁻² to 10 ⁵ Hz. The surface resistance (R) is obtained by approximating the arc of the negative resistance component of the obtained Nyquist plot with a semicircle. The double layer capacity (Cdl) is determined.

(20) Area of negative electrode plate The area of the negative electrode plate is not particularly limited, but is preferably designed to be slightly larger than the opposing positive electrode plate so that the positive electrode plate does not protrude from the negative electrode plate. From the viewpoint of suppressing the life of a cycle in which charge and discharge are repeated and deterioration due to high temperature storage, it is preferable that the area be as close to the positive electrode as possible, since the ratio of electrodes that work more uniformly and effectively is increased and the characteristics are improved. In particular, when the electrode is used at a large current, the design of the electrode area is important.

(21) Thickness of negative electrode plate The thickness of the negative electrode plate is designed according to the positive electrode plate used, and is not particularly limited, but the thickness of the composite layer obtained by subtracting the metal foil thickness of the core is It is usually 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and usually 150 μm or less, preferably 120 μm or less, more preferably 100 μm or less.

<2-3-3. Alloy materials>
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 (these are referred to below). , And may be abbreviated as “specific metal element”), and alloys or compounds containing these atoms. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

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

  Moreover, the compound which these complex compounds combined with several elements, such as a metal simple substance, an alloy, or a nonmetallic element, can also be mentioned. 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.

In addition, although the capacity per unit mass is inferior to that of using a single metal or an alloy, the following compounds containing silicon and / or tin are also preferred because of excellent cycle characteristics.
(I) The element ratio of silicon and / or tin and oxygen is usually 0.5 or more, preferably 0.7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably An oxide of silicon and / or tin of 1.3 or less, more preferably 1.1 or less.
(Ii) The element ratio of silicon and / or tin and nitrogen is usually 0.5 or more, preferably 0.7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably Silicon and / or tin nitride of 1.3 or less, more preferably 1.1 or less.
(Iii) The element ratio of silicon and / or tin to carbon is usually 0.5 or more, preferably 0.7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably Silicon and / or tin carbide of 1.3 or less, more preferably 1.1 or less.

<2-3-4. Composition, physical properties and preparation method of negative electrode using alloy material>
The negative electrode using the alloy material in the non-aqueous electrolyte battery of the present invention can be manufactured using any known method. Specifically, as a manufacturing method of the negative electrode, for example, a method in which a negative electrode active material added with a binder or a conductive material is roll-formed as it is to form a sheet electrode, or a compression-molded pellet electrode and In general, the above-mentioned method is applied to a negative electrode current collector (hereinafter sometimes abbreviated as “negative electrode current collector”) by a method such as a coating method, a vapor deposition method, a sputtering method, or a plating method. A method of forming a thin film layer (negative electrode active material layer) containing a negative electrode active material is used. In this case, by adding a binder, a thickener, a conductive material, a solvent, etc. to the above-mentioned negative electrode active material to form a slurry, applying this to the negative electrode current collector, drying, and pressing to increase the density A negative electrode active material layer is formed on the negative electrode current collector.

  Examples of the material of the negative electrode current collector include steel, copper alloy, nickel, nickel alloy, and stainless steel. Of these, copper foil is preferred from the viewpoint of easy processing into a thin film and cost.

  The thickness of the negative electrode current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. This is because if the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely if it is too thin, handling may be difficult.

  In addition, in order to improve the binding effect with the negative electrode active material layer formed on the surface, the surface of these negative electrode current collectors is preferably subjected to a roughening treatment in advance. Surface roughening methods include blasting, rolling with a rough surface roll, polishing cloth with a fixed abrasive particle, grinding wheel, emery buff, machine that polishes the current collector surface with a wire brush equipped with steel wire, etc. Examples thereof include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method.

  Further, in order to reduce the mass of the negative electrode current collector and improve the energy density per mass of the battery, a perforated negative electrode current collector such as an expanded metal or a punching metal can be used. This type of negative electrode current collector can be freely changed in mass by changing its aperture ratio. Further, when a negative electrode active material layer is formed on both sides of this type of negative electrode current collector, the negative electrode active material layer is further less likely to peel due to the rivet effect through this hole. However, when the aperture ratio becomes too high, the contact area between the negative electrode active material layer and the negative electrode current collector becomes small, and thus the adhesive strength may be lowered.

  The slurry for forming the negative electrode active material layer is usually prepared by adding a binder, a thickener and the like to the negative electrode material. In addition, the “negative electrode material” in this specification refers to a material in which a negative electrode active material and a conductive material are combined.

  Content of the negative electrode active material in a negative electrode material is 70 mass% or more normally, Preferably it is 75 mass% or more, and is 97 mass% or less normally, Preferably it is 95 mass% or less. When the content of the negative electrode active material is too small, the capacity of the secondary battery using the obtained negative electrode tends to be insufficient, and when the content is too large, the content of the binder or the like is relatively insufficient. This is because the strength of the negative electrode tends to be insufficient. In addition, when using 2 or more types of negative electrode active materials together, what is necessary is just to make it the total amount of a negative electrode active material satisfy | fill the said range.

  Examples of the conductive material used for the negative electrode include metal materials such as copper and nickel; carbon materials such as graphite and carbon black. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. In particular, it is preferable to use a carbon material as the conductive material because the carbon material acts as an active material. The content of the conductive material in the negative electrode material is usually 3% by mass or more, preferably 5% by mass or more, and usually 30% by mass or less, preferably 25% by mass or less. When the content of the conductive material is too small, the conductivity tends to be insufficient. When the content is too large, the content of the negative electrode active material or the like is relatively insufficient, which tends to decrease the battery capacity and strength. . In addition, when using 2 or more types of electrically conductive materials together, what is necessary is just to make it the total amount of an electrically conductive material satisfy | fill the said range.

  As the binder used for the negative electrode, any material can be used as long as it is a material safe with respect to the solvent and the electrolytic solution used at the time of producing the electrode. Examples thereof include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene / butadiene rubber / isoprene rubber, butadiene rubber, ethylene-acrylic acid copolymer, and ethylene / methacrylic acid copolymer. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The content of the binder is usually 0.5 parts by mass or more, preferably 1 part by mass or more, and usually 10 parts by mass or less, preferably 8 parts by mass or less with respect to 100 parts by mass of the negative electrode material. When the content of the binder is too small, the strength of the obtained negative electrode tends to be insufficient. When the content is too large, the content of the negative electrode active material and the like is relatively insufficient, and thus the battery capacity and conductivity tend to be insufficient. It is because it becomes. In addition, when using 2 or more types of binders together, what is necessary is just to make it the total amount of a binder satisfy | fill the said range.

  Examples of the thickener used for the negative electrode include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The thickener may be used as necessary, but when used, the content of the thickener in the negative electrode active material layer is usually preferably in the range of 0.5% by mass or more and 5% by mass.

  The slurry for forming the negative electrode active material layer is prepared by mixing the negative electrode active material with a conductive material, a binder, or a thickener as necessary, and using an aqueous solvent or an organic solvent as a dispersion medium. . As the aqueous solvent, water is usually used, but a solvent other than water such as alcohols such as ethanol or cyclic amides such as N-methylpyrrolidone is used in combination at a ratio of about 30% by mass or less with respect to water. You can also. As the organic solvent, usually, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and aromatic carbonization such as anisole, toluene and xylene Examples thereof include alcohols such as hydrogens, butanol and cyclohexanol, among which cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide are preferable. . In addition, any one of these may be used alone, or two or more may be used in any combination and ratio.

  The viscosity of the slurry is not particularly limited as long as it is a viscosity that can be applied onto the current collector. What is necessary is just to prepare suitably by changing the usage-amount of a solvent etc. at the time of preparation of a slurry so that it may become the viscosity which can be apply | coated.

  The obtained slurry is applied onto the above-described negative electrode current collector, dried, and then pressed to form a negative electrode active material layer. The method of application is not particularly limited, and a method known per se can be used. The drying method is not particularly limited, and a known method such as natural drying, heat drying, or reduced pressure drying can be used.

The electrode structure when the negative electrode active material is made into an electrode by the above method is not particularly limited, but the density of the active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ^{−. 3} or more, and particularly preferably 1.3 g · ^{cm -3} or more, and preferably 2 g · ^{cm -3} or less, more preferably 1.9 g · ^{cm -3} or less, 1.8 g · ^{cm -3} or less Further preferred is 1.7 g · cm ⁻³ or less.

  When the density of the active material existing on the current collector exceeds the above range, the active material particles are destroyed, the initial irreversible capacity increases, and the non-aqueous electrolyte solution near the current collector / active material interface There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability. On the other hand, below the above range, the conductivity between the active materials may be reduced, the battery resistance may be increased, and the capacity per unit volume may be reduced.

<2-3-5. Lithium-containing metal composite oxide material>
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, 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 (1). In the general formula (1), 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 (1)
[In the general formula (1), 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 (1),
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
This structure is particularly preferable because of a good balance of battery performance.

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

  The configuration and preparation method of the negative electrode using the lithium-containing metal composite oxide material as the negative electrode active material are not particularly limited, and known methods can be applied.

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

<2-4-1. Cathode active material>
The positive electrode active material used for the positive electrode will be described below.

(1) Composition The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable as the transition metal of the lithium transition metal composite oxide. Specific examples include lithium-cobalt composite oxides such as LiCoO ₂ and LiNiO ₂ . Lithium / nickel composite oxides, LiMnO ₂ , LiMn ₂ O ₄ , Li ₂ MnO _{4 and} other lithium / manganese composite oxides, Al, Ti , V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, and those substituted with other metals such as Si.

As specific examples of the substituted ones, for example, LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , 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 metals.

(2) Surface coating A material having a composition different from that of the main constituent of the positive electrode active material (hereinafter sometimes abbreviated as “surface adhering substance”) attached to the surface of the positive electrode active material. It can also be used. Examples of 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, Examples thereof include sulfates such as calcium sulfate and aluminum sulfate, and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

  These surface adhering substances are, for example, a method in which they are dissolved or suspended in a solvent and impregnated and added to the positive electrode active material and then dried, or a surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material. Then, 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.

  The mass of the surface adhering material adhering to the surface of the positive electrode active material is usually 0.1 ppm or more, preferably 1 ppm or more, more preferably 10 ppm or more, and usually 20% with respect to the mass of the positive electrode active material. Or less, preferably 10% or less, more preferably 5% or less.

  The surface adhering substance can suppress the oxidation reaction of the non-aqueous electrolyte on the surface of the positive electrode active material, and can improve the battery life. However, when the adhesion amount is less than the above range, the effect is not sufficiently exhibited. When the adhesion amount is more than the above range, the resistance may increase in order to inhibit the entry / exit of lithium ions, so the above range is preferable.

(3) Shape As the shape of the positive electrode active material particles, a lump shape, a polyhedron shape, a sphere shape, an oval sphere shape, a plate shape, a needle shape, a column shape, etc., which are conventionally used, are used. It is preferable to form secondary particles, and the shape of the secondary particles is spherical or elliptical.

  In general, an electrochemical element expands and contracts as the active material in the electrode expands and contracts as it is charged and discharged. Therefore, the active material is easily damaged due to the stress or the conductive path is broken. Therefore, the primary particles are aggregated to form secondary particles rather than a single particle active material having only primary particles, so that the stress of expansion and contraction is relieved and deterioration is prevented.

  In addition, spherical or oval spherical particles are less oriented at the time of forming the electrode than the plate-like equiaxially oriented particles, so there is less expansion and contraction of the electrode during charge and discharge, and when creating the electrode Also in the mixing with the conductive material, it is preferable because it is easily mixed uniformly.

(4) Tap density The tap density of the positive electrode active material is usually 1.3 g · cm ⁻³ or more, preferably 1.5 g · cm ⁻³ or more, more preferably 1.6 g · cm ⁻³ or more. 7 g · cm ⁻³ or more is particularly preferable, usually 2.5 g · cm ⁻³ or less, and preferably 2.4 g · cm ⁻³ or less.

  By using a metal composite oxide powder having a high tap density, a high-density positive electrode active material layer can be formed. Therefore, when the tap density of the positive electrode active material is lower than the above range, the amount of the dispersion medium necessary for forming the positive electrode active material layer increases, and the necessary amount of the conductive material and the binder increases, The filling rate of the positive electrode active material is limited, and the battery capacity may be limited. In general, the tap density is preferably as large as possible, but there is no particular upper limit. However, if the tap density is less than the above range, diffusion of lithium ions in the positive electrode active material layer using the non-aqueous electrolyte solution as a medium becomes rate-determining, and load characteristics are likely to deteriorate. There is a case.

The tap density is measured by passing a sieve having a mesh size of 300 μm, dropping the sample onto a 20 cm ³ tapping cell to fill the cell volume, and then using a powder density measuring instrument (eg, tap denser manufactured by Seishin Enterprise Co., Ltd.). Then, tapping with a stroke length of 10 mm is performed 1000 times, and the density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the positive electrode active material of the present invention.

(5) Median diameter d50
The median diameter d50 (secondary particle diameter when primary particles are aggregated to form secondary particles) of the positive electrode active material particles should also be measured using a laser diffraction / scattering particle size distribution analyzer. Can do.

  The median diameter d50 is usually 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more, particularly preferably 3 μm or more, and usually 20 μm or less, preferably 18 μm or less, more preferably 16 μm or less. 15 μm or less is particularly preferable.

  If the median diameter d50 is below the above range, a high bulk density product may not be obtained. If the median diameter d50 is above the above range, it takes time to diffuse lithium in the particles. That is, when an active material, a conductive material, a binder, or the like is slurried with a solvent and applied in a thin film shape, streaks may occur. In addition, the filling property at the time of positive electrode preparation can be further improved by mixing two or more positive electrode active materials having different median diameters d50 in an arbitrary ratio.

  The median diameter d50 is measured by using a 0.1% by mass sodium hexametaphosphate aqueous solution as a dispersion medium, and using LA-920 manufactured by HORIBA, Ltd. as a particle size distribution meter, the refractive index is adjusted to 1.24 after ultrasonic dispersion for 5 minutes. Set and measure.

(6) Average primary particle diameter When primary particles aggregate to form secondary particles, the average primary particle diameter of the positive electrode active material is usually 0.01 μm or more, preferably 0.05 μm or more, and It is more preferably not less than 08 μm, particularly preferably not less than 0.1 μm, usually not more than 3 μm, preferably not more than 2 μm, more preferably not more than 1 μm, particularly preferably not more than 0.6 μm.

  If the above range is exceeded, it may be difficult to form spherical secondary particles, which may adversely affect the powder filling property, or the specific surface area will be greatly reduced, which may increase the possibility that the battery performance such as output characteristics will deteriorate. Because there is. Further, if the value is below the above range, the performance of the secondary battery may be deteriorated, for example, the reversibility of charge / discharge is inferior because the crystal is not developed.

  The average 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.

(7) BET specific surface area As for the BET specific surface area of the positive electrode active material, the value of the specific surface area measured using the BET method is usually 0.2 m ² · g ⁻¹ or more and 0.3 m ² · g ⁻¹ or more. 0.4 m ² · g ⁻¹ or more is more preferable, usually 4.0 m ² · g ⁻¹ or less, preferably 2.5 m ² · g ⁻¹ or less, and 1.5 m ² · g ^{−. 1} or less is more preferable.

  When the value of the BET specific surface area is below the above range, the battery performance tends to be lowered. Moreover, when it exceeds the said range, a tap density becomes difficult to raise and the applicability | paintability at the time of positive electrode active material formation may fall.

  The BET specific surface area is measured using a surface area meter (a fully automatic surface area measuring device manufactured by Okura Riken). The sample was preliminarily dried at 150 ° C. for 30 minutes under a nitrogen flow, and then a nitrogen helium mixed gas that was accurately adjusted so that the relative pressure of nitrogen with respect to atmospheric pressure was 0.3 was used. It is measured by the nitrogen adsorption BET one-point method by the flow method. The specific surface area determined by the measurement is defined as the BET specific surface area of the anode active material of the present invention.

(8) Method for Producing Positive Electrode Active Material The method for producing the positive electrode active material is not particularly limited as long as it does not exceed the gist of the present invention. The method is used.

In particular, various methods are conceivable for producing a spherical or elliptical active material. For example, transition metal source materials such as transition metal nitrates and sulfates, and other element source materials as required. Is dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring to produce and recover a spherical precursor, which is dried as necessary, and then LiOH, Li ₂ CO ₃ , LiNO There is a method in which an active material is obtained by adding a Li source such as ₃ and baking at a high temperature.

In addition, as an example of another method, transition metal raw materials such as transition metal nitrates, sulfates, hydroxides, oxides and the like, and if necessary, raw materials of other elements are dissolved or pulverized and dispersed in a solvent such as water. Then, it is dry-molded with a spray dryer or the like to obtain a spherical or oval spherical precursor, and a Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ is added to the precursor and calcined at a high temperature to obtain an active material Is mentioned.

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

<2-4-2. Electrode structure and fabrication method>
Below, the structure of the positive electrode of the non-aqueous electrolyte battery of this invention and its preparation method are demonstrated.

(1) Method for Producing Positive Electrode The positive electrode is produced by forming a positive electrode active material layer containing positive electrode active material particles and a binder on a current collector. The production of the positive electrode using the positive electrode active material can be produced by any known method. That is, a positive electrode active material and a binder, and if necessary, a conductive material and a thickener mixed in a dry form are pressure-bonded to a 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 usually 10% by mass or more, preferably 30% by mass or more, particularly preferably 50% by mass or more, and usually 99.9% by mass or less, preferably 99%. It is below mass%. This is because if the content of the positive electrode active material in the positive electrode active material layer is less than the above range, the electric capacity may be insufficient. Moreover, it is because the intensity | strength of a positive electrode may be insufficient when it exceeds the said range. In addition, the positive electrode active material powder of this invention may be used individually by 1 type, and may use together 2 or more types of a different composition or different powder physical properties by arbitrary combinations and ratios.

(2) Conductive material As the conductive material, a known conductive material can be arbitrarily used. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbonaceous materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together 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, and usually 50% by mass or less, preferably 30% by mass in the positive electrode active material layer. % Or less, more preferably 15% by mass or less.

  If the content is lower than the above range, the conductivity may be insufficient. Moreover, when it exceeds the said range, battery capacity may fall.

(3) Binder The binder used for the production of the positive electrode active material layer 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 during electrode production.

  In the case of the coating method, any material can be used as long as it is dissolved or dispersed in the liquid medium used during electrode production. Specific examples include polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitro Resin polymers such as cellulose; rubbery polymers such as SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene propylene rubber; styrene butadiene styrene block Copolymer or its hydrogenated product, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / ethylene copolymer, styrene / isoprene / styrene block copolymer or its hydrogenated product, etc. Thermoplastic Stoma-like polymers; soft resin-like polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride (PVdF), Examples include fluorine-based polymers such as polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene / ethylene copolymers; polymer compositions having ion conductivity of alkali metal ions (particularly lithium ions). 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 3% by mass or more, and usually 80% by mass or less, and 60% by mass. % Or less is preferable, 40% by mass or less is more preferable, and 10% by mass or less is particularly preferable.

  When the ratio of the binder is below the above range, the positive electrode active material cannot be sufficiently retained, the positive electrode has insufficient mechanical strength, and battery performance such as cycle characteristics may be deteriorated. Moreover, when it exceeds the said range, it may lead to a battery capacity or electroconductivity fall.

(4) Liquid medium The liquid medium for forming the slurry may be a solvent capable of dissolving or dispersing the positive electrode active material, the conductive material, the binder, and the thickener used as necessary. For example, the type is not particularly limited, and either an aqueous solvent or an organic solvent may be used.

  Examples of the aqueous medium include water and a mixed medium of alcohol and water. 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 and tetrahydrofuran (THF); N-methylpyrrolidone (NMP), dimethylformamide and dimethyl Examples include amides such as acetamide; aprotic polar solvents such as hexamethylphosphalamide and dimethyl sulfoxide. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

(5) Thickener When using an aqueous medium as a liquid medium for forming a slurry, 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 as long as the effects of the present invention are not significantly impaired. Specifically, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and these Examples include salts. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  Furthermore, when using a thickener, the ratio of the thickener to the 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, Preferably it is 3 mass% or less, More preferably, it is 2 mass% or less. If it falls below the above range, applicability may be remarkably reduced, and if it exceeds the above range, the ratio of the active material in the positive electrode active material layer is lowered, the battery capacity is reduced, and the resistance between the positive electrode active materials. May increase.

(6) Consolidation 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 g · cm ⁻³ or more, more preferably 1.5 g · cm ⁻³ or more, particularly preferably 2 g · cm ⁻³ or more, and preferably 4 g · cm ⁻³ or less. 3.5 g · cm ⁻³ or less is more preferable, and 3 g · cm ⁻³ or less is particularly preferable.

  If the density of the positive electrode active material layer exceeds the above range, the permeability of the non-aqueous electrolyte solution to the vicinity of the current collector / active material interface may decrease, and the charge / discharge characteristics at a high current density may decrease. Moreover, when less than the said range, the electroconductivity between active materials may fall and battery resistance may increase.

(7) Current collector The material of the positive electrode current collector is not particularly limited, and any known material can be used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbonaceous 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, foam metal, etc. A carbon 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.

  The thickness of the metal thin film is arbitrary, but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less.

  If the thin film is thinner than the above range, the strength required for the current collector may be insufficient. Moreover, when a thin film is thicker than the said range, a handleability may be impaired.

  The ratio of the thickness of the current collector to the positive electrode active material layer is not particularly limited, but the (active material layer thickness on one side immediately before non-aqueous electrolyte injection) / (current collector thickness) is usually 150 or less. Yes, preferably 20 or less, particularly preferably 10 or less, usually 0.1 or more, preferably 0.4 or more, and particularly preferably 1 or more. When the ratio of the thickness of the current collector to the positive electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge / discharge. On the other hand, below the above range, the volume ratio of the current collector to the positive electrode active material may increase, and the battery capacity may decrease.

(8) Electrode area From the viewpoint of increasing the high current density and stability at high temperatures, the area of the positive electrode active material layer is preferably larger than the outer surface area of the battery outer case. Specifically, the total electrode area of the positive electrode with respect to the surface area of the exterior of the secondary battery is preferably 20 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.

(9) Thickness of the positive electrode plate Although the thickness of the positive electrode plate is not particularly limited, from the viewpoint of high capacity, high output, and high rate characteristics, the thickness of the composite layer obtained by subtracting the metal foil thickness of the core material is: 10 μm or more is preferable, 20 μm or more is more preferable, 200 μm or less is preferable, and 100 μm or less is more preferable with respect to one side of the current collector.

<2-5. Separator>
Usually, 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.

  There is no restriction | limiting in particular about the material and shape of a separator, As long as the effect of this invention is not impaired remarkably, a well-known thing can be employ | adopted arbitrarily. 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 the glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, 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.

  Although the thickness of the separator is arbitrary, it is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only battery performance such as rate characteristics may be lowered, but also the energy density of the entire non-aqueous electrolyte battery may be lowered.

  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. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

  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. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.

  On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. 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-mentioned 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.

<2-6. 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 below the above range, the battery capacity becomes small. Also, if the above range is exceeded, the void space is small, the battery expands, and the member expands or the vapor pressure of the electrolyte liquid component increases and the internal pressure rises. In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

[Current collection structure]
The current collecting structure is not particularly limited, but in order to more effectively realize the high current density charge / discharge characteristics by the non-aqueous electrolyte solution of the present invention, a structure that reduces the resistance of the wiring part and the joint part is used. It is preferable. Thus, when internal resistance is reduced, the effect of using the non-aqueous electrolyte solution of this invention is exhibited especially favorable.

  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.

  By optimizing the above structure, the internal resistance can be made as small as possible. In a battery used at a large current, the impedance measured by the 10 kHz AC method (hereinafter sometimes abbreviated as “DC resistance component”) is preferably 10 milliohms (mΩ) or less, and the DC resistance component is 5 mΩ or less. More preferably. When the DC resistance component is 0.1 mΩ or less, the output characteristics are improved, but the ratio of the current collecting structure used increases and the battery capacity may decrease.

[Exterior case]
The material of the outer case is not particularly limited as long as it is a stable substance with respect to the nonaqueous 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 the outer case using the above metals, the metal is welded to each other by laser welding, resistance welding, ultrasonic welding, or a sealed sealing structure, or the above metal is used to crimp the structure using a resin gasket. To do. 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.

[Protective element]
PTC (Positive Temperature Coefficient), thermal fuse, thermistor whose resistance increases when abnormal heat generation or excessive current flows, current flowing in the circuit due to sudden rise in battery internal pressure or internal temperature during abnormal heat generation For example, a valve (current cutoff valve) that shuts off the current 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.

[Exterior body]
The non-aqueous electrolyte battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.

  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.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

Each evaluation method of the battery obtained by the following Example and the comparative example is shown below.
[Evaluation of initial discharge capacity]
A lithium secondary battery is charged to 4.1 V at a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to enhance adhesion between electrodes, and then a constant current of 0.2 C Was discharged to 3V. This is done for 3 cycles to stabilize the battery. In the 4th cycle, after charging to 4.1V with a constant current of 0.5C, charging is performed until the current value reaches 0.05C with a constant voltage of 4.1V. The initial discharge capacity was determined by discharging to 3 V at a constant current of 0.2C. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 2C represents a current value that is twice that, and 0.2C represents a current value that is 1/5 of the current value.

[Evaluation of -30 ° C output]
The battery whose initial capacity evaluation was completed was charged at 25 ° C. with a constant current of 0.2 C so as to be half the initial discharge capacity. This was discharged at −30 ° C. for 10 seconds at 0.2 C, 0.4 C, 0.8 C, 1 C, and 2 C, respectively, and the voltage at the 10 second was measured. The area of a triangle surrounded by the current-voltage straight line and the lower limit voltage (3 V) was defined as output (W).

[Evaluation of 25 ° C output]
The battery whose initial capacity evaluation was completed was charged at 25 ° C. with a constant current of 0.2 C so as to be half the initial discharge capacity. This was discharged at 25 ° C. for 10 seconds at 1 C, 2 C, 4 C, 7 C, 10 C and 15 C, respectively, and the voltage at the 10 second was measured. The area of a triangle surrounded by the current-voltage straight line and the lower limit voltage (3 V) was defined as output (W).

[Evaluation of thermal stability]
After the initial capacity evaluation was completed, the battery was charged at 25 ° C. with a constant current of 0.2 C to 4.1 V, and then charged with a constant voltage of 4.1 V until the current value reached 0.05 C. The calorific value of this rechargeable battery from room temperature to 300 ° C. was measured with a Calve calorimeter.

[Evaluation of cycle characteristics]
The battery for which the initial capacity evaluation was completed was charged to 4.3 V at a constant current of 2 C and discharged to 3.0 V at a constant current of 2 C at 60 ° C. Charging / discharging was repeated as one cycle, 500 cycles were performed, and the discharge capacity maintenance rate (%) at the 500th cycle with respect to the discharge capacity at the first cycle was determined.

Example 1
[Production of negative electrode]
Artificial graphite powder KS-44 (manufactured by Timcal, trade name) 98 parts by mass, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration 1% by mass of carboxymethylcellulose sodium) as a thickener and binder, and 2 parts by mass of an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber 50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to one side of a copper foil having a thickness of 10 μm, dried, and rolled to a thickness of 75 μm with a press, and the active material layer size was 30 mm wide, 40 mm long, 5 mm wide, It cut out into the shape which has an uncoated part of 9 mm in thickness, and was set as the negative electrode.

[Production of positive electrode]
90% by mass of LiNi _0.33 Mn _0.33 Co _0.33 O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride (PVdF) as a binder Were slurried by mixing in N-methylpyrrolidone solvent. The obtained slurry was applied to one side of an aluminum foil having a thickness of 15 μm, dried, and rolled to a thickness of 80 μm with a press, and the active material layer had a width of 30 mm, a length of 40 mm, and a width of 5 mm. It cut out into the shape which has a 9-mm uncoated part, and was set as the positive electrode.

[Manufacture of electrolyte]
99.5 parts by mass of a mixture of monofluoroethylene carbonate (MFEC), sulfolane (SLF), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) (volume ratio 10: 20: 30: 40) under a dry argon atmosphere, 0.5 parts by mass of lithium difluorophosphate (LiPO ₂ F ₂ ) was mixed, and then sufficiently dried LiPF ₆ was dissolved at a rate of 1.0 mol / L to obtain an electrolytic solution.

[Manufacture of lithium secondary batteries]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, and the positive electrode to prepare 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 then the electrolyte was poured into the bag to create a vacuum. Sealing was performed, and a sheet-like battery was produced and evaluated. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 2
In the electrolyte solution of Example 1, except that the volume ratio of the mixture of monofluoroethylene carbonate (MFEC), sulfolane (SLF), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) was 10: 30: 30: 30 In the same manner as in Example 1, a sheet-like lithium secondary battery was produced and evaluated. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 3
In the electrolyte solution of Example 1, the volume ratio of the mixture of monofluoroethylene carbonate (MFEC), sulfolane (SLF), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) was set to 20: 20: 30: 30 In the same manner as in Example 1, a sheet-like lithium secondary battery was produced and evaluated. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 4
A sheet-like lithium secondary battery was produced and evaluated in the same manner as in Example 1 except that in the electrolyte solution of Example 1, sulfolane (SLF) was changed to 3-methylsulfolane (3MSLF). The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 5
In the electrolytic solution of Example 1, a mixture (volume ratio 10: 20: 20: 50) of monofluoroethylene carbonate (MFEC), sulfolane (SLF), gamma butyrolactone (GBL), and ethyl methyl carbonate (EMC) was used. In the same manner as in Example 1, a sheet-like lithium secondary battery was produced and evaluated. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 6
In the electrolytic solution of Example 1, a mixture (volume ratio 10: 20: 10: 60) of monofluoroethylene carbonate (MFEC), sulfolane (SLF), ethylene carbonate (EC) and ethyl methyl carbonate (EMC) was used. In the same manner as in Example 1, a sheet-like lithium secondary battery was produced and evaluated. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 7
In the electrolytic solution of Example 1, a mixture of monofluoroethylene carbonate (MFEC), sulfolane (SLF), gamma butyrolactone (GBL), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) (volume ratio 10:20:20: 30:20) A sheet-like lithium secondary battery was produced and evaluated in the same manner as in Example 1 except that the ratio was 30:20). The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 8
In the electrolyte solution of Example 1, a mixture of monofluoroethylene carbonate (MFEC), sulfolane (SLF), ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) (volume ratio 10:20:10: 30:30) A sheet-like lithium secondary battery was prepared and evaluated in the same manner as in Example 1 except that the evaluation was performed. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Comparative Example 1
Use an electrolyte prepared by dissolving LiPF ₆ in a mixture of sulfolane (SLF) and ethyl methyl carbonate (EMC) (volume ratio 30:70) to a ratio of 1.0 mol / L. A sheet-like lithium secondary battery was prepared and evaluated in the same manner as in Example 1 except that. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Comparative Example 2
94 parts by mass (volume ratio 30:70) of a mixture of sulfolane (SLF) and gamma butyrolactone (GBL) and 2 parts by mass of vinylene carbonate (VC), vinyl ethylene carbonate (VEC) and trioctyl phosphate (TOP), respectively. Then, a sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that an electrolyte prepared by dissolving LiPF ₆ sufficiently dried to a ratio of 1.0 mol / L was used. Evaluation was performed. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Comparative Example 3
94 parts by mass (volume ratio 30:70) of a mixture of sulfolane (SLF) and gamma butyrolactone (GBL) and 2 parts by mass of vinylene carbonate (VC), vinyl ethylene carbonate (VEC) and trioctyl phosphate (TOP), respectively. Then, a sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that an electrolyte prepared by dissolving LiBF ₄ sufficiently dried to a ratio of 1.0 mol / L was used. Evaluation was performed. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Comparative Example 4
A mixture of monofluoroethylene carbonate (MFEC), sulfolane (SLF) and ethyl methyl carbonate (EMC) (volume ratio 2:28:70) was mixed, and then fully dried LiPF ₆ was added at a rate of 1.0 mol / L. A sheet-like lithium secondary battery was prepared and evaluated in the same manner as in Example 1 except that the electrolytic solution prepared by dissolution was used. The components of the electrolytic solution are shown in Table 1. The evaluation results are shown in Tables 2 and 3.

Example 9
A sheet-like lithium secondary battery was prepared using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 1, and thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 10
A sheet-like lithium secondary battery was prepared using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 2, and thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 11
A sheet-like lithium secondary battery was prepared using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 3, and the thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 12
A sheet-like lithium secondary battery was produced using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 4, and thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 13
A sheet-like lithium secondary battery was produced using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 5, and thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 14
A sheet-like lithium secondary battery was prepared using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 6, and the thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 15
A sheet-like lithium secondary battery was prepared using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 7, and the thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 16
A sheet-like lithium secondary battery was produced using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 8, and the thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Comparative Example 5
Manufactured by mixing a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (volume ratio 3: 7) and then dissolving LiPF ₆ sufficiently dried to a ratio of 1.0 mol / L. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that the electrolytic solution was used, and thermal stability was evaluated by thermal analysis. The evaluation results are shown in Table 4.

Example 17
A sheet-like lithium secondary battery was produced using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 1, and the cycle characteristics were evaluated. The evaluation results are shown in Table 5.

Example 18
A sheet-like lithium secondary battery was prepared using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 2, and the cycle characteristics were evaluated. The evaluation results are shown in Table 5.

Example 19
A sheet-like lithium secondary battery was produced using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Example 8, and the cycle characteristics were evaluated. The evaluation results are shown in Table 5.

Comparative Example 6
A sheet-like lithium secondary battery was produced using the positive electrode, the negative electrode, and the electrolytic solution obtained in the same manner as in Comparative Example 5, and the cycle characteristics were evaluated. The evaluation results are shown in Table 5.

  As is clear from Tables 1 to 3, the battery using the nonaqueous electrolytic solution according to the present invention is excellent in output characteristics at normal temperature and low temperature, as is clear from Examples 1 to 8. On the other hand, in the battery (Comparative Examples 1-4) using what is not the non-aqueous electrolyte which concerns on this invention, output characteristics are inferior. Further, as is clear from the results of Examples 9 to 16, it can be seen that the safety of the battery is high because the heat generation rate of the battery is lower than that of Comparative Example 5 configured by the prior art. Further, as is clear from the results of Examples 18 to 20, it can be seen that the capacity deterioration in the high-temperature cycle at a high voltage is smaller than that of Comparative Example 6 configured by the prior art and excellent in durability.

  Since the nonaqueous electrolyte battery using the nonaqueous electrolyte of the present invention maintains a high capacity and is excellent in safety and the like, it can be used for various known applications. Specific examples include, for example, 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. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Car, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, etc. Can be mentioned.

Claims (6)

A non-aqueous electrolyte solution for a non-aqueous electrolyte battery containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte,
The non-aqueous electrolyte contains a cyclic carbonate containing fluorine and a cyclic sulfone compound,
The volume of the cyclic carbonate containing fluorine is 8 to 40% by volume, and the total of the volume of the cyclic carbonate containing fluorine and the volume of the cyclic sulfone compound is 20 to 60% by volume with respect to the entire non-aqueous solvent. A non-aqueous electrolyte characterized by the above.   The non-aqueous electrolyte solution according to claim 1, wherein the cyclic sulfone compound is sulfolane and / or a sulfolane derivative.   The non-aqueous electrolyte solution according to claim 1 or 2, wherein the cyclic carbonate containing fluorine is monofluoroethylene carbonate and / or difluoroethylene carbonate.   The non-aqueous electrolyte solution according to any one of claims 1 to 3, wherein the non-aqueous electrolyte solution contains at least one chain carbonate in an amount of 30 to 80% by volume with respect to the entire non-aqueous solvent.   The non-aqueous electrolyte solution according to any one of claims 1 to 4, wherein the non-aqueous electrolyte solution contains a cyclic carbonate and / or a cyclic carboxylic acid ester in an amount of 5 to 40% by volume based on the whole non-aqueous solvent. .   A non-aqueous electrolyte battery comprising 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 1 to 5. A non-aqueous electrolyte battery characterized by the above.