JP3497812B2 - Non-aqueous electrolyte secondary battery using non-aqueous electrolyte - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery using a non-aqueous electrolyte containing a silicon compound having an unsaturated bond, and more specifically to using a silicon compound in the electrolyte. Since the rate of change in electric capacity and internal resistance during repeated charging and discharging is small, and the increase in internal resistance at low temperatures is small, a non-aqueous electrolyte solution that can maintain a high electric capacity and has excellent low-temperature characteristics is used. The non-aqueous electrolyte secondary battery described above.

[0002]

2. Description of the Related Art With the spread of portable electronic devices such as portable personal computers and handy video cameras in recent years, non-aqueous electrolyte secondary batteries having high voltage and high energy density are used as power sources. It has become widely used. Further, due to environmental issues, battery vehicles and hybrid vehicles that use electric power as part of power are being put to practical use.

However, the non-aqueous electrolyte secondary battery shows a decrease in electric capacity and an increase in internal resistance at low temperatures or by repeating charging and discharging, and lacks reliability as a stable power supply source.

Various additives have been proposed to improve the stability and electrical characteristics of non-aqueous electrolyte secondary batteries. For example,
JP-A-10-326611 proposes to use tetramethyl silicate as an organic solvent in an organic solvent-based electrolyte. However, although this additive improves the cycle characteristics, it has a drawback that the capacity decreases. Further, JP-A-10-55822 proposes an electrolyte solution having flame retardancy by using a silane compound such as octyltriethoxysilane as a flame retardant organic solvent. However, although this additive improves flame retardancy,
The electrical properties were not fully satisfactory. Further, Japanese Patent Laid-Open No. 11-16602 discloses that Si
An electrolytic solution to which an organosilicon compound having a -N bond is added has been proposed. However, although this additive can prevent the generation of halogen acid due to the mixing of water and prevent the deterioration of the battery to some extent, the electrical characteristics by repeating the cycle were not sufficiently satisfactory.

Therefore, an object of the present invention is that the rate of change of the electric capacity and the internal resistance at the time of repeated charging and discharging is small and the increase of the internal resistance at a low temperature is small, so that the cycle characteristic and the low temperature characteristic of maintaining a high electric capacity are obtained. excellent non-aqueous electrolyte solution
And to provide a nonaqueous electrolyte secondary battery using the.

[0006]

Means for Solving the Problems As a result of various studies in view of the present situation, the present inventors have added a silicon compound having an unsaturated bond containing at least one unsaturated bond to an electrolytic solution. Thus, it was found that a non-aqueous electrolyte secondary battery having excellent cycle characteristics and low temperature characteristics can be obtained.

The present invention has been made on the basis of the above findings, in which the electrolyte salt is a cyclic carbonate compound and a chain carbon nanotube.
In over DOO compound of at least one or more content to have <br/> organic solvent dissolved electrolyte non-aqueous electrolyte secondary battery <br/> with each by the following general formula (1) in the electrolyte there is provided a non-aqueous electrolyte secondary battery you characterized by containing a silicon compound having an unsaturated bond represented 0.05-3 vol%.

[0008]

[Chemical 3]

[0009]

DETAILED DESCRIPTION OF THE INVENTION will be described in detail nonaqueous electrolyte secondary battery using the nonaqueous electrolytic solution of the present invention are described below.

In the general formula (1), the alkyl group and the alkoxy group represented by R _{1 to} R ₆ are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, Heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl,
1 to 12 carbon atoms such as decyl, undecyl and dodecyl
And the alkoxy groups derived from these groups. Examples of the alkenyl group and alkenyloxy group include alkenyl groups having 2 to 8 carbon atoms such as vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-octenyl and the like. And an alkenyloxy group derived from the group Examples of the alkynyl group and alkynyloxy group include alkynyl groups having 2 to 8 carbon atoms such as ethynyl, 2-propynyl, and 1,1-dimethyl-2-propynyl, and alkynyloxy groups derived from these groups. Examples of the aryl group and the aryloxy group include aryl groups having 6 to 12 carbon atoms such as phenyl, tolyl, xylyl and tert-butylphenyl, and aryloxy groups derived from these groups.

In the general formula (1), the alkylene group and alkylenedioxy group represented by X are methylene, ethylene, trimethylene, 2,2-dimethyltrimethylene, tetramethylene, pentamethylene,
Examples thereof include alkylene groups having 1 to 8 carbon atoms such as hexamethylene and alkylenedioxy groups derived from these groups. Examples of the alkenylene group and the alkenylenedioxy group include vinylene, propenylene, isopropenylene, butenylene, pentenylene, and other alkenylene groups having 2 to 8 carbon atoms, and alkenylenedioxy groups derived from these groups. Examples of the alkynylene group and the alkynylenedioxy group include an alkynylene group having 2 to 8 carbon atoms such as ethynylene, propynylene, butynylene, pentynylene, and 1,1,4,4-tetramethylbutenylene or an alkynylenedioxy group. Can be mentioned. Examples of the arylene group and the arylenedioxy group include arylene groups having 6 to 12 carbon atoms such as phenylene, methylphenylene, dimethylphenylene and tert-butylphenylene, and arylenedioxy groups derived from these groups.

As the silicon compound having an unsaturated bond represented by the above general formula (1), more specifically, the following compound No. 1 to No. 26 and the like. However, the silicon compound used in the present invention is not limited to the following examples.

[0013]

Embedded image Compound No. 1

[0014]

Embedded image Compound No. Two

[0015]

Embedded image Compound No. Three

[0016]

Embedded image Compound No. Four

[0017]

Embedded image Compound No. 5

[0018]

Embedded image Compound No. 6

[0019]

Embedded image Compound No. 7

[0020]

Embedded image Compound No. 8

[0021]

Embedded image Compound No. 9

[0022]

Embedded image Compound No. 10

[0023]

Embedded image Compound No. 11

[0024]

Embedded image Compound No. 12

[0025]

Embedded image Compound No. Thirteen

[0026]

Embedded image Compound No. 14

[0027]

Embedded image Compound No. 15

[0028]

Embedded image Compound No. 16

[0029]

Embedded image Compound No. 17

[0030]

Embedded image Compound No. 18

[0031]

Embedded image Compound No. 19

[0032]

Embedded image Compound No. 20

[0033]

Embedded image Compound No. 21

[0034]

Embedded image Compound No. 22

[0035]

Embedded image Compound No. 23

[0036]

Embedded image Compound No. 24

[0037]

Embedded image Compound No. 25

[0038]

Embedded image Compound No. 26

The above-mentioned silicon compound having an unsaturated bond is a known compound, and the synthetic method thereof is not particularly limited, but for example, by a dehydrogenation coupling reaction of a hydrogen-containing silicon compound and a hydroxyl-containing silicon compound. The above compound No. 1 is obtained.

The above-mentioned silicon compound is a compound which is easily self-polymerized, and it is possible to form a stable film by the polymerization reaction at the electrode interface at the beginning of the cycle and to suppress the increase of the interface resistance due to the cycle. Conceivable.
In order to realize this effect, 100 volume of electrolyte solution
% With respect to, is contained the silicon compound in the amount of 0.05 to 3% by volume, and more preferably 0.1 to 3% by volume.
If the content is less than 0.05% by volume, the effect is hardly recognized, and if the content exceeds 3 % by volume, the effect is not exhibited any more, which is not only wasteful but also adversely affects the characteristics of the electrolytic solution. Since it may affect, it is not preferable.

The silicon compound according to the present invention is a cyclic compound.
Carbonate compound and chain carbonate compound respectively
It is used as a non-aqueous electrolyte secondary battery by including it in an organic solvent containing at least one kind . As a non-aqueous solvent
And cyclic carbonate compounds and chain carbonate compounds
Not only excellent cycle characteristics by using the combination of, but also the viscosity of the electrolytic solution, the electric capacity of the obtained battery,
It is possible to provide a non-aqueous electrolytic solution having a well-balanced output and the like.

Examples of the non-aqueous solvent used in the non-aqueous electrolyte secondary battery of the present invention are listed below. However, the non-aqueous solvent used in the present invention is not limited to the following examples.

Since the cyclic carbonate compound, the cyclic ester compound, the sulfone or sulfoxide compound, and the amide compound have a high relative dielectric constant, they play a role of increasing the dielectric constant of the electrolytic solution. Specifically, as the cyclic carbonate compound, Examples thereof include ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate, butylene carbonate, etc., examples of the cyclic ester compound include γ-butyrolactone, γ-valerolactone, etc., and examples of the sulfone or sulfoxide compound include:
Examples thereof include sulfolane, sulfolene, tetramethylsulfolane, diphenyl sulfone, dimethyl sulfone, and dimethyl sulfoxide, and examples of the amide compound include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and the like.

Chain carbonate compounds, chain or cyclic ether compounds, chain ester compounds and the like can reduce the viscosity of the electrolytic solution. Therefore, the mobility of electrolyte ions can be increased, and the battery characteristics such as output density can be improved. Moreover, since the viscosity is low, the performance of the electrolytic solution at low temperatures can be improved.
Specifically, the chain carbonate compound includes dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), ethyl-n-butyl carbonate, methyl-t-butyl carbonate, di-i-propyl. Carbonate, t-butyl-
Examples of the chain or cyclic ether compound include i-propyl carbonate, and dimethoxyethane (DM
E), ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolane, dioxane and the like.

Further, as the above chain ester compound,
The carboxylic acid ester compound represented by the following general formula (2) may be mentioned, and examples of the alkyl group having 1 to 4 carbon atoms in the following general formula (2) include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, Tertiary butyl can be mentioned, and specifically, methyl formate, ethyl formate, methyl acetate,
Ethyl acetate, propyl acetate, butyl acetate, butyl acetate, methyl propionate, ethyl propionate and the like can be mentioned. These carboxylic acid ester compounds have a low freezing point, and by further adding them to a cyclic or chain carbonate compound, the battery characteristics can be improved even at low temperatures. The addition amount of the carboxylic acid ester compound is preferably 1 to 50% by volume in 100 volumes of the non-aqueous solvent. In addition, acetonitrile, propionitrile, nitromethane and their derivatives can also be used.

[0046]

[Chemical 30]

Further, the alkylenebiscarbonate compound classified into the chain carbonate compound represented by the following general formula (3) can reduce the volatility of the electrolytic solution,
Further, since the storage characteristics at high temperature are excellent, the battery characteristics at high temperature can be improved.

[0048]

[Chemical 31]

In the above general formula (3), R ₉ and R ₁₁
Examples of the alkyl group represented by include methyl, ethyl, propyl, butyl, and the like, and examples of the alkylene group represented by R ₁₀ include ethylene, propylene, dimethylpropylene, and the like. Specific examples of the alkylenebiscarbonate compound include 1,2-bis (methoxycarbonyloxy) ethane, 1,2-bis (ethoxycarbonyloxy) ethane, and 1,2-bis (ethoxycarbonyloxy) propane. Can be mentioned.

The glycol diether compound represented by the following general formula (4), which is classified as a chain ether compound, has a terminal-like group substituted with a fluorine atom, so that it acts like a surfactant at the electrode interface. It is possible to enhance the affinity of the non-aqueous electrolyte with the electrode, to reduce the initial internal resistance of the battery and the mobility of lithium ions.

[0051]

[Chemical 32]

In the above general formula (4), R ₁₂ and R ₁₄
Examples of the alkyl group represented by include methyl, trifluoromethyl, ethyl, trifluoroethyl, propyl, pentafluoropropyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl and the like, and R ₁₃
Examples of the alkylene group represented by include ethylene, propylene, difluoropropylene, butylene and the like.
Specific examples of the glycol diether compound include ethylene glycol bis (trifluoroethyl) ether, i-propylene glycol (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether, diethylene glycol bis (trifluoroethyl). ) Ether and the like can be mentioned.

Further, in order to impart flame retardancy to the non-aqueous electrolytic solution of the present invention, a halogen-based, phosphorus-based or other flame retardant can be appropriately added as a flame retardant.

As the phosphorus-based flame retardant, it is preferable to add one or more phosphoric acid ester compounds represented by the following general formula (5), (6) or (7).

[0055]

[Chemical 33]

Examples of the alkyl group represented by R ₁₅ , R ₁₆ , R ₁₇ and R ₁₉ in the above general formulas (5) and (6) include methyl, ethyl, propyl, butyl, pentyl and hexyl. Examples of the fluorine-substituted alkyl group include 2-fluoroethyl, 2,2,2-
Trifluoroethyl etc. are mentioned.

Examples of the alkylene group represented by R ₁₈ in the above general formula (6) include ethylene, propylene, trimethylene and 2,2-dimethyltrimethylene, and examples of the alkenylene group include vinylene and butenylene. Examples of the alkynylene group include ethynylene, propynylene, 2-butynylene, 1,1,4,4-
Tetramethyl-2-butynylene, 1,4-dimethyl-
1,4-diethyl-2-butynylene, 1,4-dimethyl-1,4-diisobutyl-2-butynylene and the like can be mentioned.

3 which gives a trivalent alcohol residue having 3 to 18 carbon atoms represented by R ₂₀ in the above general formula (7)
Examples of the polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, 1,2,4
-Trihydroxybutane and the like.

More specifically, as the phosphoric acid ester compounds represented by the above general formulas (5) to (7), the following compound Nos. 27-35 are mentioned. However, the phosphoric acid ester compound used in the present invention is not limited to the following compounds.

[0060]

Embedded image Compound No. 27

[0061]

Embedded image Compound No. 28

[0062]

Embedded image Compound No. 29

[0063]

Embedded image Compound No. Thirty

[0064]

Embedded image Compound No. 31

[0065]

Embedded image Compound No. 32

[0066]

Embedded image Compound No. 33

[0067]

Embedded image Compound No. 34

[0068]

Embedded image Compound No. 35

The amount of the phosphoric acid ester compound represented by the above general formulas (5) to (7) is preferably 5 to 100% by mass, and preferably 10 to 50% by mass with respect to the organic solvent constituting the electrolytic solution. Particularly preferred. If it is less than 5% by mass, a sufficient flame retarding effect cannot be obtained.

The method for synthesizing the phosphoric acid ester compounds represented by the above general formulas (5) to (7) is not particularly limited, but can be easily prepared, for example, by reacting phosphorus oxychloride with the corresponding alcohol. Can be synthesized.

As the electrolyte salt used in the present invention, a conventionally known electrolyte salt can be used.
₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , L
iN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ ,
LiSbF ₆ , LiSiF ₅ , LiAlF ₄ , LiSC
N, LiClO ₄ , LiCl, LiF, LiBr, Li
I, LiAlF ₄ , LiAlCl ₄ , NaClO ₄ , N
aBF ₄ , NaI, and the like, among them, LiPF ₆ ,
Inorganic salts such as LiBF ₄ , LiClO ₄ , and LiAsF ₆ ,
In addition, CF ₃ SO ₃ Li, N (CF ₃ SO ₂ ) ₂ L
i, a combination of one or more salts selected from the group consisting of organic salts such as C (CF ₃ SO ₂ ) ₃ Li and the like is preferable because of excellent electrical characteristics.

The electrolyte salt has a concentration of 0.
1 to 3.0 mol / liter, particularly 0.5 to 2.0 mol / liter
It is preferable to dissolve in the non-aqueous solvent (organic solvent) so that the volume becomes liter. If the concentration of the electrolytic solution is less than 0.1 mol / liter, a sufficient current density may not be obtained, and if it is more than 3.0 mol / liter, the stability of the electrolytic solution may be impaired.

[0073]

Electrode material for non-aqueous electrolyte secondary battery of the present invention
There is a positive electrode and a negative electrode, and the positive electrode is a positive electrode active material.
A current collector made of a slurry of quality, binder and conductive material
A sheet-shaped product which is applied and dried is used. Positive
TiS as the active material ₂, TiS₃, MoS₃, F
eS₂, Li_(1-x)MnO₂, Li_(1-x)Mn₂O _Four,
Li_(1-x)CoO₂, Li_(1-x)NiO₂, LiV₂O
₃, V₂O_FiveEtc. An example of the positive electrode active material
X in the figure indicates a number of 0 to 1. Of these positive electrode active materials
Among them, a composite oxide of lithium and a transition metal is preferable, and L
iCoO₂, LiNiO₂, LiMn₂O_Four, LiMn
O₂, LiV₂O₃Etc. are preferred. Negative electrode and positive electrode active material
Examples of the binding agent of polyvinylidene fluoride,
Litetrafluoroethylene, EPDM, SBR, NB
R, fluororubber, and the like, but are not limited thereto.
Yes.

As the negative electrode, usually, a negative electrode active material and a binder which are slurried in a solvent are applied to a current collector and dried to form a sheet. Examples of the negative electrode active material include inorganic compounds such as lithium, lithium alloys and tin compounds, carbonaceous materials and conductive polymers. In particular, a carbonaceous material that can store and release lithium ions with high safety is preferable. This carbonaceous material is not particularly limited, but graphite and petroleum-based coke, coal-based coke, petroleum-based pitch carbide, coal-based pitch carbide, phenol resin, crystalline cellulose and other resin carbides, etc. Examples thereof include carbon materials, furnace black, acetylene black, pitch-based carbon fibers, PAN-based carbon fibers and the like.

As the conductive material of the positive electrode, fine particles of graphite, carbon black such as acetylene black, fine particles of amorphous carbon such as needle coke, etc. are used, but not limited thereto. As a solvent for forming a slurry, an organic solvent that dissolves a binder is usually used. For example, N-
Methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone,
Methyl acetate, methyl acrylate, diethyltriamine,
Examples thereof include NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran,
It is not limited to this. In some cases, the active material is slurried with latex such as SBR by adding a dispersant and a thickener to water.

The current collector of the negative electrode is usually copper, nickel,
Stainless steel, nickel-plated steel or the like is used, and usually aluminum, stainless steel, nickel-plated steel or the like is used for the positive electrode current collector.

In the non-aqueous electrolyte secondary battery of the present invention, a separator is used between the positive electrode and the negative electrode, but a commonly used polymeric microporous film can be used without particular limitation. For example, polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyether sulfone, polycarbonate,
Polyamides, polyimides, polyethers such as polyethylene oxide and polypropylene oxide, various celluloses such as carboxymethyl cellulose and hydroxypropyl cellulose, polymer compounds mainly containing poly (meth) acrylic acid and various esters thereof, and the like Examples thereof include derivatives, films made of copolymers and mixtures thereof, and the like. Further, such a film may be used alone, or a multi-layer film obtained by stacking these films may be used. Further, various additives may be used in these films, and the kind and content thereof are not particularly limited.
Among these microporous films, polyethylene, polypropylene, polyvinylidene fluoride and polysulfone are preferably used for the non-aqueous electrolyte secondary battery of the present invention.

These separator films are made finely porous so that the electrolytic solution can soak into the separator films and allow ions to easily pass therethrough. As the method of making the microporosity, a “phase separation method” in which a solution of a polymer compound and a solvent is microphase-separated to form a film, and the solvent is extracted and removed to make it porous, and a molten polymer compound is highly drafted. The film is extruded into a film and then heat-treated to arrange the crystals in one direction, and further, a "stretching method" for forming a gap between the crystals to form a porous structure, and the like, which is appropriately selected depending on the polymer film used. It In particular, the phase separation method is preferably used for polyethylene and polyvinylidene fluoride preferably used in the present invention.

For the purpose of further improving safety, the electrode material, the electrolytic solution and the separator used in the non-aqueous electrolytic solution secondary battery of the present invention contain a phenolic antioxidant, a phosphorus antioxidant and a thioether antioxidant. An inhibitor and a hindered amine light stabilizer may be added.

Examples of the above-mentioned phenolic antioxidant include 1,6-hexamethylene bis [(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionic acid amide], 4,4'-thiobis ( 6-tert-butyl-m-
Cresol), 4,4'-butylidene bis (6-tert-butyl-m-cresol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,3. 5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate,
1,3,5-Tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-Tris (3,5-di-tert-butyl-4-hydroxybenzyl)
-2,4,6-trimethylbenzene, tetrakis [3-
(Methyl 3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, thiodiethylene glycol bis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylenebis [(3,5-Di-tert-butyl-4-hydroxyphenyl)
Propionate], bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, bis [2-tert-butyl-4-methyl-6- (2-hydroxy-3-) Tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris [(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate,
3,9-Bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5 , 5] undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], and the like, and 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode material, More preferably, 0.05 to 5 parts by weight is used.

Examples of the phosphorus-based antioxidant include
Trisnonylphenyl phosphite, tris [2-tert-butyl-4- (3-tert-butyl-4-hydroxy-5-
Methylphenylthio) -5-methylphenyl] phosphite, tridecylphosphite, octyldiphenylphosphite, di (decyl) monophenylphosphite,
Di (tridecyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl- 4-Methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tri-tert-butylphenyl) pentaerythritol diphosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite, tetra (tridecyl) ) Isopropylidene diphenol diphosphite, tetra (tridecyl)-
4,4'-n-butylidene bis (2-tert-butyl-5-
Methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butanetriphosphite, tetrakis (2,4-di-tert-butylphenyl) biphenyl Range Phosphonite, 9,10-Dihydro-9-
Oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis (4,6-tert-butylphenyl) -2-ethylhexylphosphite, 2,2 '
-Methylenebis (4,6-tert-butylphenyl) -octadecylphosphite, 2,2'-ethylidenebis (4,6-di-tert-butylphenyl) fluorophosphite, tris (2-[(2,4,8 , 10-Tetrakis tert-butyldibenzo [d, f] [1,3,2] dioxaphosphepin-6-yl) oxy] ethyl) amine, 2-
Ethyl-2-butyl propylene glycol and 2,4,6
-Tri-tert-butylphenol phosphite and the like.

As the above thioether type antioxidant,
Examples thereof include dialkyl thiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate and distearyl thiodipropionate, and pentaerythritol tetra (β-alkylmercaptopropionate).

Examples of the hindered amine light stabilizer include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, and 2 , 2,6,6-tetramethyl-4-piperidyl benzoate, bis (2,2
2,6,6-Tetramethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-)
Piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, bis ( 2,2,6,6-tetramethyl-4-piperidyl) .di (tridecyl) -1,2,
3,4-butanetetracarboxylate, bis (1,
2,2,6,6-Pentamethyl-4-piperidyl) -di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,4,4-pentamethyl-4-piperidyl ) -2-Butyl-2- (3,5-di-tert-butyl-4-hydroxybenzyl) malonate, 1-
(2-Hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis (2,2,6,6-tetramethyl-4)
-Piperidylamino) hexane / 2,4-dichloro-6
-Morpholino-s-triazine polycondensate, 1,6-bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-tertiaryoctylamino-s-triazine Polycondensate, 1,5,8,12-tetrakis [2,4-bis (N-butyl-N- (2,2,
6,6-Tetramethyl-4-piperidyl) amino) -s
-Triazin-6-yl] -1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis [2,4
-Bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8-12-tetraazadodecane, 1,6,11-Tris [2,4-bis (N-butyl-N- (2,2,6,6-tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane, 1,6,11-Tris [2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-
Examples thereof include hindered amine compounds such as piperidyl) amino) -s-triazin-6-yl] aminoundecane.

The non-aqueous electrolyte secondary battery of the present invention having the above structure is not particularly limited in its shape and can be used as a battery of various shapes such as a coin type, a cylindrical type and a square type. FIG. 1 shows an example of a coin-type battery of the non-aqueous electrolyte secondary battery of the present invention, and FIGS. 2 and 3 show an example of a cylindrical battery of the non-aqueous electrolyte secondary battery of the present invention.

In the coin type non-aqueous electrolyte secondary battery 10 shown in FIG. 1, 1 is a positive electrode capable of releasing lithium ions,
Reference numeral 1a is a positive electrode current collector, 2 is a negative electrode made of a carbon chamber material capable of storing and releasing lithium ions released from the positive electrode 1, 2
a is a negative electrode current collector, 3 is the non-aqueous electrolytic solution of the present invention, 4 is a positive electrode case made of stainless steel, 5 is a negative electrode case made of stainless steel,
6 is a polypropylene gasket, and 7 is a polyethylene separator.

In the cylindrical non-aqueous electrolyte secondary battery 10 'shown in FIGS. 2 and 3, 11 is a negative electrode, 12 is a negative electrode assembly, 13 is a positive electrode, 14 is a positive electrode current collector, and 15 is a main battery. The nonaqueous electrolytic solution of the invention, 16 is a separator, 17 is a positive electrode terminal, 1
8 is a negative electrode terminal, 19 is a negative electrode plate, 20 is a negative electrode lead, 21
Is a positive electrode plate, 22 is a positive electrode lead, 23 is a case, 24 is an insulating plate, 25 is a gasket, 26 is a safety valve, and 27 is a PTC.
It is an element.

Although the mechanism of action of the present invention is not clear, it is considered that in the initial cycle, the silicon compound used in the present invention undergoes a polymerization reaction at the electrode interface to form a film. Therefore, it is considered that the film is more stable than the case where no silicon compound is added, so that the side reaction between the electrode and the electrolytic solution accompanying the cycle can be suppressed, and the increase in the internal resistance due to the cycle can be suppressed. . Further, since the resistance of this coating is small at low temperatures, it is considered that a high discharge capacity can be maintained.

[0089]

EXAMPLES The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples.

[Fabrication of Positive Electrode] LiNi as a positive electrode active material
85 parts by weight of O _{2 and} acetylene black 10 as a conductive agent
Parts by weight, polyvinylidene fluoride as a binder (PVD
F) 5 parts by weight were mixed to obtain a positive electrode material. This positive electrode material was dispersed in N-methyl-2-pyrrolidone (NMP) to form a slurry. This slurry is applied to both sides of a positive electrode current collector made of aluminum, dried and press-molded,
The positive electrode plate was used. Then, this positive electrode plate was cut into a predetermined size, and the electrode mixture in the portion to be the lead tab weld for current extraction was scraped off to prepare a sheet-shaped positive electrode.

[Preparation of Negative Electrode] 92.5 parts by weight of carbon material powder was mixed with 7.5 parts by weight of PVDF to prepare a negative electrode material. This negative electrode material was dispersed in NMP to form a slurry. Similar to the positive electrode, this slurry was applied to both surfaces of a copper negative electrode current collector, dried, and press-molded to obtain a negative electrode plate.
Then, this negative electrode plate was cut into a predetermined size, and the sheet-shaped negative electrode was produced by scraping off the electrode mixture in the portion to be the lead tab welded portion for current extraction.

[Preparation of Non-Aqueous Electrolyte Solution] That is, a non-aqueous electrolyte solution was prepared as described in Examples 1-1 to 1-31 and Comparative Examples 1-1 to 1-3 below. An organic solvent was mixed at the volume% shown below, LiPF ₆ was dissolved at a concentration of 1 mol / liter, and a test compound (described in Table 1) was added at the compounding amount (volume%) described in Table 1. The non-aqueous electrolyte was used.

[Production of Battery] The sheet-shaped positive electrode and the sheet-shaped negative electrode obtained as described above were wound with a microporous polyethylene film having a thickness of 25 μm interposed therebetween to obtain a wound electrode body. Formed. The obtained wound electrode body was inserted into the case and held in the case. At this time, the current collecting leads having one ends welded to the lead tab welded portions of the sheet-shaped positive electrode and the sheet-shaped negative electrode were joined to the positive electrode terminal or the negative electrode terminal of the case. Then, the non-aqueous electrolyte was injected into the case holding the spirally wound electrode body, and the case was sealed and sealed. With the above procedure, φ18
mm, a cylindrical nonaqueous electrolyte secondary battery (cylindrical lithium secondary battery) having an axial length of 65 mm was produced.

Various characteristics of the cylindrical lithium secondary battery were measured by the following measuring methods. The results are shown in Table 1 below.

<Initial discharge capacity> First, charging current 0.25
Constant-current constant-voltage charging was performed at 4.1 mA / cm ² to 4.1 V, and constant-current discharging was performed at 3.03 mA / cm ² to 3.0 V. Next, a constant current constant voltage charge was performed at a charging current of 1.1 mA / cm ² to 4.1 V, and a constant current discharge was performed at a discharge current of 1.1 mA / cm ² to 3.0 V four times, and then a charging current of 1.
Constant-current constant-voltage charge at 1 mA / cm ² up to 4.1 V, the discharge current 0.33 mA / cm ² up to 3.0V constant current discharge, the discharge capacity at this time was a battery initial capacity. The measurement was performed in an atmosphere of 20 ° C.

<High temperature cycle characteristic test> The above cylindrical type
Place the UM secondary battery in a thermostatic chamber with an ambient temperature of 60 ° C,
Charging current 2.2mA / cm²Constant current charging up to 4.1V
Discharge current 2.2 mA / cm ²Constant current discharge up to 3V
Was repeated 500 times. afterwards,
Return the ambient temperature to 20 ℃ and charge current 1.1mA / c
m²Constant current constant voltage charge up to 4.1V, discharge current 0.3
3 mA / cm²Constant current discharge to 3.0V at
The discharge capacity retention rate is the ratio of the discharge capacity of the battery to the initial capacity of the battery.
It was

<Measurement of increase rate of internal resistance> First, the internal resistance of the battery is measured at 20 ° C. or −30.
AC impedance measuring device with constant current and constant voltage charging up to 3.75V at a charging current of 1.1mA / cm ² at ℃
( Manufactured by Toyo Corporation): Frequency Response Analyzer sol
artron 1260, potentio / galvanostat solartron 1287), frequency 100
Scanning was performed from kHz to 0.02 Hz, and a Cole-Cole plot showing the imaginary part on the vertical axis and the real part on the horizontal axis was created. Then, in this Cole-Cole plot, the circular arc portion was fitted with a circle, and the larger value of the two points intersecting the real number portion of this circle was taken as the resistance value, which was taken as the internal resistance of the battery. The rate of increase in internal resistance was defined by the following equation after measuring the internal resistance before and after the cycle test. (Internal resistance increase rate) = (resistance value after cycle test) /
(Resistance value before cycle test) × 100

<Low Temperature Characteristic Evaluation Test> The discharge capacity ratio and internal resistance ratio at −30 ° C. to 20 ° C. were measured. Discharge capacity ratio = (Discharge capacity at −30 ° C.) / (Discharge capacity at 20 ° C.) × 100 Internal resistance ratio = (Internal resistance at −30 ° C.) / (Internal resistance at 20 ° C.)

[Examples 1-1 to 1-31 and Comparative Example 1-
1-1-3] LiPF ₆ was dissolved in a mixed solvent consisting of 30% by volume of ethylene carbonate and 70% by volume of diethyl carbonate at a concentration of 1 mol / liter, and the test compound (Table 1
Reference) was added to make an electrolytic solution. In Comparative Example 1 -1 without addition of test compound, Comparative Examples 1-2 and Comparative Examples 1-3
Is a comparative compound No. shown below as a test compound. 36 and 3
7 were used respectively. As a result, when the battery initial capacity in Comparative Example 1-1 was set to 100, the battery initial capacities of the other Examples and Comparative Examples also showed values equal to or higher than the same value.

[0100]

[Table 1]

[0101]

Embedded image Comparative compound No. 36

[0102]

Embedded image Comparative compound No. 37

[Examples 2-1 to 2-10 and Comparative Example 2-
1-2-2] 1 mol / LiPF _{6 in a} mixed solvent composed of 30% by volume of ethylene carbonate, 60% by volume of diethyl carbonate and 10% by volume of triethyl phosphate.
It was dissolved at a concentration of 1 liter, and 0.5% by volume of a test compound (see Table 2) was further added to obtain a non-aqueous electrolyte.

Then, the discharge capacity retention rate (%) after 500 cycles and the internal resistance increase rate (%) after 500 cycles were respectively measured by the same measuring method as the high temperature cycle characteristic test and the measurement of the internal resistance increase rate. It was measured. A flame retardancy test was also conducted by the method shown below. The results are shown in Table 2 below.

<Flame Retardancy Test> The width of the non-aqueous electrolyte solution described in Examples 2-1 to 2-10 and Comparative examples 2-1 to 2-2 was 15
mm, a length of 320 mm and a thickness of 0.04 mm of separator manila paper were immersed, and then the separator manila paper was suspended vertically for 3 minutes to remove excess non-aqueous electrolyte. The Manila paper for a separator impregnated with this non-aqueous electrolyte was pierced into a supporting needle of a sample stage having a supporting needle at 25 mm intervals and fixed horizontally. This sample table is 25
Put in a metal box of 0mm x 250mm x 500mm,
One end of the Manila paper for separator was ignited with a lighter, and the burned length of the Manila paper for separator (combustion length) was measured.
When the combustion length was less than 10 mm, it was evaluated as having self-extinguishing property, and when the combustion length was 10 mm or more, it was evaluated as having no self-extinguishing property and evaluated as x.

[0106]

[Table 2]

Examples 3-1 to 3-5 LiPF ₆ was dissolved in a mixed solvent having the composition shown in Table 3 below at a concentration of 1 mol / liter, and the test compound No. 1
(See Table 3) was added to 1.0% by volume to obtain a non-aqueous electrolyte.
Then, the discharge capacity ratio (%) was measured by the same measuring method as in the low temperature characteristic evaluation test. The results are shown in Table 3 below.

[0108]

[Table 3]

As is clear from the evaluation results of Tables 1 and 2, the non-aqueous electrolyte secondary battery using the non-aqueous electrolyte solution to which the silicon compound of the present invention is added has a discharge capacity according to a cycle.
The decrease in quantity is small. On the other hand, in the non-aqueous electrolyte secondary batteries using the non-aqueous electrolytes of Comparative Examples 1-1 and 2-1 to which the silicon compound was not added, it was confirmed that the discharge capacity after cycling was greatly reduced. did it.

It was also confirmed that the discharge capacity can be improved and the internal resistance can be reduced when the silicon compound according to the present invention is added even at a low temperature.

Furthermore, in Table 3 above, by adding an ester compound having a low freezing point as a solvent for the low temperature electrolytic solution, the test of Example 1-4 described above (electrolytic solution containing no ester compound having a low freezing point) was performed. It was confirmed that the discharge capacity at low temperature was improved in comparison.

[0112]

By using the non-aqueous electrolyte solution containing the silicon compound of the present invention, a non-aqueous electrolyte secondary battery having excellent cycle characteristics and low temperature characteristics can be provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing an example of the structure of a coin-type battery of a non-aqueous electrolyte secondary battery of the present invention.

FIG. 2 is a schematic diagram showing a basic configuration of a cylindrical battery of the non-aqueous electrolyte secondary battery of the present invention.

FIG. 3 is a perspective view showing, as a cross section, an internal structure of a cylindrical battery of the non-aqueous electrolyte secondary battery of the present invention.

[Explanation of symbols]

1 positive electrode 1a Positive electrode current collector 2 Negative electrode 2a Negative electrode current collector 3 Electrolyte 4 Positive case 5 Negative electrode case 6 gasket 7 separator 10 Coin type non-aqueous electrolyte secondary battery 10 'Cylindrical non-aqueous electrolyte secondary battery 11 Negative electrode 12 Negative electrode assembly 13 Positive electrode 14 Positive electrode assembly 15 Electrolyte 16 separator 17 Positive terminal 18 Negative electrode terminal 19 Negative electrode plate 20 Negative electrode lead 21 Positive plate 22 Positive electrode lead 23 cases 24 insulating plate 25 gasket 26 Safety valve 27 PTC element

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuki Takeuchi 7-35 Higashiohisa, Arakawa-ku, Tokyo Within Asahi Denka Kogyo Co., Ltd. In DENSO (72) Inventor Naomi Awano, 1-1, Showa-cho, Kariya city, Aichi Inside DENSO CORPORATION (56) References JP-A-9-306544 (JP, A) JP-A-6-89741 (JP, A) JP-A-8-195221 (JP, A) JP-A-9-171825 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 10/40

Claims (10)

(57) [Claims] 1. An electrolyte salt and a chain of a cyclic carbonate compound
Containing at least one kind of carbonate compound
Non-aqueous electrolysis using an electrolytic solution dissolved in an organic solvent which has
In a liquid secondary battery , 0.05 to 3 silicon compounds having an unsaturated bond represented by the following general formula (1) are contained in an electrolytic solution.
% Non-aqueous electrolyte secondary battery . [Chemical 1] Wherein in the general formula (1), the non-aqueous electrolyte according to claim 1, wherein n contains a silicon compound is 1 two
Next battery . 3. In the above general formula (1), R _{1 to} R ₆
The non-aqueous electrolyte secondary battery according to claim 1, further comprising a silicon compound in which at least one of them is a vinyl group. 4. The non-aqueous electrolyte secondary battery according to claim 1, further comprising a silicon compound represented by the general formula (1), wherein X is an oxygen atom. 5. In the general formula (1), n is 1.
R ₁ and R ₄ are vinyl groups, and X is an oxygen atom.
A silicon compound according to any one of claims 1 to 4 is included.
Non-aqueous electrolyte secondary battery listed . 6. The non-aqueous electrolyte secondary battery according to claim 1, further comprising a silicon compound in the general formula (1), wherein X is an ethynylene group. 7. The organic solvent is, La lactone compound, non-water according to any one of claims 1 to 6 including the ethers, one or more selected from the group of non-aqueous solvent consisting of sulfolane and dioxolanes Electrolyte secondary battery . 8. Any of the following general formula (2) according to claim 7, further compounding the carboxylic acid ester compound represented by
Non-aqueous electrolyte secondary battery of crab according. [Chemical 2] 9. The electrolyte salt is lithium ion and PF.
^{_{6 -, BF 4 -, ClO}} 4 - and AsF ₆ ^- and the inorganic salt and lithium ion composed of an anion selected from among ^{_{SO 3 CF 3 -, N (}} CF 3 SO 2) 2 -, C
The (CF ₃ SO ₂ ) ₃ ^— and a combination with at least one salt selected from the group of organic salts composed of these derivatives, or a combination with two or more salts. Non-aqueous electrolyte secondary battery. 10. A non-aqueous electrolyte according to any one of claims 1-9 containing 0.1-2.0% by volume silicon compound having an unsaturated bond represented by the general formula (1) Double Next power
Pond .